CA2090372A1 - Apparatus for accurately laying conduit within a trench and method of using the same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An apparatus and method for laying conduit within a trench, using a separable boxlike structure with end walls, side walls, a fill bin compartment internal of the boxlike structure for receiving fill material and dispensing fill material onto the bottom of the trench, and a conduit laying compartment through which conduit is fed for positioning on the bottom of the trench. The boxlike structure has a rigidly mounted tow bar which facilitates application of vertical, longitudinal and lateral forces on the boxlike structure to thereby enable an operator of the apparatus to maneuver it on-grade and in alignment along the bottom of the trench. The boxlike structure is maintained on-grade and in alignment with the assistance of a laser transmitter/receiver assembly and several grade-maintenance features, including a shearing blade which automatically adjusts its vertical position in response to the laser. A reflecting mirror is provided on the boxlike structure for intercepting and reflecting a laser beam used for alignment downwardly into the apparatus toward the conduit being laid. A weighted pendulum maintains the mirror oriented to insure reflection of the beam in a vertical direction independently of the movements of the boxlike structure. In this way, an indicator or sensor in the immediate vicinity of the conduit can provide very accurate alignment information independently of the degree of tilt or excessive lateral shifts of the boxlike structure. When an obstacle is encountered, the boxlike structure may be separated into an upper portion and lower portion so that the upper portion can be unconnected and removed from the lower portion. The laying of conduit within the trench can continue using only the lower portion until it is clear of the obstacle and the upper portion can be repositioned on the lower portion. The apparatus may also have a dewatering system, a conduit setting system, and a system for dispensing fill material around the conduit and onto the bottom of the trench.

Description

~AT~Q~ YIN5:; CO~ 3 ;7 2 W~ ~
~3 1992 ~

T"ne present invenlion relates to an apparatus used for laying conduit in a tr~nch, and more particu1ar1y to a trench boot spparatus and festures ot the trench boot used in and methods used for laying conduit in alignment and on-erade on she bonom of a trench.
BAC}CGROUND QF THE~ INVENTION
Various types of apparatus have been used to 1ay subterranean conduit. Over the years a number of trenching devices have been developed to meet ~he needs of underground contractors. When doing subterranean work, various types of ground conditions and obstacles are encountered. The ground to be worked may be stable or unstable, it may contain numerous rocks or other obstacles such as utility lines and other underground conduits, or it may have a high water table. Each different type of ground condition requires that the underground contractor pay particular attention to the safety of the workmen and that procedures designed to achieve the greatest efficiency are followed.
Where the ground is stable and maintains its form when a deep trench is excavated therein, excavstion and conduit laying can be done quickly and efficiently without significant dan6er of the trench walls collapsing. Frequently, in stable ground conditions a conduit 1aying apparatus such as a trencher with a trench bont is used to cut the trench and lay a uniform layer of fill material in the bo~tom of the trench upon which the conduit is positioned and aligned. Also, since the trench boots have walls to shore up the walls of the trench, the use of a trench boot provides an added safety precaution which protects the workmen within the trench from collapse of the trench walls.

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In unstable ground conditions, the use of conduit laying ayparatus S'4C h as trench boots or trench boxes becomes more cntical. Unstable ground is more prone to collapse into the trench. l his creates significant problems to underground contractors. Li~e and limb of the workmen ~vithin the trench can be endsn~ered by collapsing trench walls. Further, it is not infrequent that progress in laying conduit is slow and tedious, because delays are caused by collapsing walls and other problems caused by the unstable ground.
When a trencb boot or trench box is not used in unstable ground conditions, the walls of the trench must be sloped back at an angle of repose such that the walls are not likely to collapse into the trench. This means that the excavator must remove considerably more earth from the trench, causing time delays and added expense. For example, if the instability of the ground required that the trench walls be sloped back 45 degrees, for a trench two (2) feet wide and ten (10) feet deep, the excavator must remove 120 cubic feet of earth for each foot of length of the trench. This is an additional 100 cubic feet in excess of the 20 cubic feet for the needed trench. In this instance, excavator time is increased five-told, and since the use of heavy equipment is quite expensive, the cost of the trenching project is also increased proportionally.
In rocky ground or earth containin~ obstacles such as utility lines, the underground contractor encounters differen~ and challenging problems. Certain kinds of excavating implements cannot be efficiently used or used without damage ei~her to the implement or the utility line. This severely lim;ts the efficiency of the under~round contractt)r in laying conduit within a trench. In snme instances, the use of certain types of excnvators and trench bnxes becomes cost prohihitive due to the time delays involved in working around ohstacles ~Q? ~2 within the trench.
Unique types of problems are presented where the conduit to be laid is in an area where there is a high water table making the ground unstable and difficuit to trench. Often, as rapidly as the trench is excavated, it begins to fill with ground water which makes it extremely d;fficult to lay a fill material bedding or the conduit in the bot20rn of the trench.
In some instances, continuous pumping of the ground water from the trench is futilc.
As can be easily seen, the laying of subterranean conduit presents many and varied problems for the underground contractor. Consequently, over the years, there have been a number of implements and apparatus which have been developcd to assist the underground contractor in laying conduit within a trench. There have been trench boxes and trench boots utilized with many different types of excavatir.g implements and in a variety of contexts.
For example, there were ditching and tilc laying machines which were developed as early as the 1880's in which a plow Gpened a ditch into which the tile was to be laid. A
hopper or chute was attached behind the plow through which tiles were fed and delivered to the bottom of the ditch and a fill material was carried down the chute to cover the positioned tile. However, the plow/hopper apparatus had si~nificant limitations. The ditch created was not very deep because as the plow was placed deeper beneath the ~round surface it became more difficult to pull the plow through the earth. Further, many a plow has been broken through the èarth. Further, many a plow has been broken upon s~rikin6 a rock hidden below the surface. More importantly, it was extremely difficult to lay t.le in a straight 5ine because plows have a tendency to mnve and deflect alon~ a path of le;ls~

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resistance. Because of the limitations of laying t;le using plows to dig the ditch, other types of trenching apparatus were developed.
Later, as trenchers with trenching booms were developed it became easier to dig trenches by moving a minimum amount of earth. Thc trenching boom of a trencher is lowered into a trench to the desired depth and a digging bucket mechanism adapted for di~ing an elongated, earthen trench is used to cut the trench in which the conduit is to be laid. The efficiency of the underground contractor was improved tremendously by thc advent of trenchers, particularly where the trench was to be excavated under stable ground conditions. The trencher could remove on1y the ear:h necessary to open the appropriate size of trench.
However, under unstable ground conditions, the walls of the trench frequently would slough into ~he trench behind the trencher boom before conduit could be laid. To minimi~e this problem trench boots were déveloped. The trench boots were typically boxlike apparatus attached behind the trencher boom. The development of trenchers with trench boot mobile housings which followed behind the digging bucket mechanism o~ the trencher boom within the trench became an integral part of efficiently laying conduit within a trench.
Illustrative examples of the type of trench boots developed to be used in conjunction with trenchers are Vnited States Patent No. 3,605,419, issued to M. E. Wells, September 20, 1971, cntitled "Method and Apparatus for Laying Pipe," and Uni~ed States Patent No. 4,028,902, issued to Courson et al., June 14, 1977, entitled "Apparatus for Laying Elongated Flexible Tuhin~." However, most trench boo~s used with trenchers are designed to 1ay only flexible pipe.

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Despite the usual ef~lciency of trench boots used with trenchers, there are certain types of ground conditions and obstacles encountered which make the use of a trencher unfeasible. For example, it is not advisable to use a trencher to excava2e a trench in areas where there are numerous utility lines. Each time a utility line is encountered, the trenching boom with the Irench boot attached thereso must be removed from the trench and the earth surrounding the utility line must be cleared away, either manually or using some other Iype of excavating implement such as a backhoe. Thus, additional heavy equipment must be continuously on call to relieve the trencher when a utility obstacle is encountered. This significantly increased the cost of the project and decreases the efficiency of the underground contractor.
More importantly, it is not unusual in such instances that the operator of the trencher will seve. utility lines within the trënch. This interjects tremendous delays and can be extremely dangerous. The utility lines must be repaired before the conduit-laying project can continue. The utility company must be notified and the subterranean work ceases until a utility company crew can repair the problem. Further, if the utility line severed is a gas Iine, there is a ser;ous chance of an explosion and the work area as well as the surroundin~
area may have to be evacuated until the problem is remedied.
Independent of those types of problems, sincç the trench boot must be removed from the trench, the pipe must be laid manually at the bottom of the trench without the safety of the trench boot walls. Consequently, in the vicinity of the utility line it is not uncommon that the walls of the trench must be sloped back at an an~le of repose sufficient to assure that the walls of the trench will not collapse on the workers as they are manually layin~ tlle 2 ~ r,,l r! ~

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conduit. This can involve moving tremendous amounts of earth causing additional delays.
Once the conduit is laid beneath the utility obstacle the trencher with the trench boot attached can be lowered into the trench and excavation can recommence. However, if another obstacle is encountered, the same tedious and time consuming process must be undei laken. rl~r inesc and other sienificant reasons, use of a trencher with a trench hoot attached thereto frequently is not the most cos; effective way to ]ay conduit.
Trench boxes have been designed to assist in laying conduit in areas where it is not advisable to use a trencher. Trench boxes usually comprise spaced walls supported by transverse rods which hold the walls in a spaced relationship. When a deep trench is required, the trench boxes are merely stacked one on top of the other until the desired height is reached. The walls of the trench box provide the abutment against which the walls of the trench would fall in the event of a collapse. In this manner, workers within the trench box are protected from trench wall collapse.
Under stable ground conditions, it is not unusual that the excavating machine ~e.~
a backhoe) can excavate a trench in advance of the trench box. The trench carved out of the earth is necessarily wider than the trench box and once the conduit is laid on the bottom of :he trench within the trench box, the trench box may be advanced for continuing the conduit-laying procedure.
Under unstable ground conditions, the use of a trench box becomes much more complex. Excavation of the trench in advance of the trench box is not feasible because the wa11s of the trench tend to collapse before the trench box can be advanced. As a result, conditions may require that a different method be used. One common method that has 2B~ '2 been used involves placing thc trench box on the surface of the ground whe.e the trench is to be excavated. Earth is excavated from within the trench box and the trench box is tapped down into place gradually as the earth within the trench box is removed. This procedure is continued until the trench box is located at the desiJed depth. The conduit can then be laid within the trench box on the bottom of the trench. lo advance the trench box, the underground contractor cannot remove the trench box from the trench because the unstable walls of the trench may collapse about the freshly laid conduit before the connecting conduit can be laid. Therefore, to lay additional conduit the trench box is pulled forward and its forward end tilted at an angle because it rests on unexcavated earth. The, more earth is excavated from within the trench box. The forward end of the trench box is tapped do vn Intil it reaches the desired depth and levels off with Ihe rear of the trench box. Additional conduit can be laid once the trench box reaches the desired depth. This procedure is performed repeatedly until the desired distance of conduit is achieved.
If a utility line is encountered the trench box usually must be removed from the trench and the area around the utility must be cleared so that conduit can be laid manually in the vicinity of the utility obstacle.
Further, with most trench box apparatus there is no facility for automatically laying a fill material bedding on-grade upon which the conduit can be laid. Usually, the fill material must be leveled manually before the conduit can be positioned. Consequently, although in some instances it may be more cost effective to use a trench box to lay conduit under certain ground conditions, it is still an extremely time consuming, difficult and expensive procedure.

2 ~ 3 7 2 Additional problems are created when ground water rapidly fills the trench. With most trench bo%es, there is no facility to handlc such seepage and pumps are Frequently used to extract as much of the ground water as possible. Where the water table is extremely high, tlle use of a trench box may not be as effective because the ground water moves the soil in too rapidly to allow the laying of the conduit.
One device wh;ch has been developed to extract ground water from a trench is illustrated ;n United States Patent No~ 4,462,715, issued to Ashbaugh, July 31, 1984, entitled "System for the One-Step Dewatering of a Trench and the Construction of a Pipelinc Bed."
The device u~ed is a stone-filled box which is pushed along the trench in increments as the trench is excavated ahead of the box. Simul!aneously, the box dispenses stone out the rear end of the box to form a bed wh;ch shores up the side of the trench and upon which conduit can be laid. A pump is provided inside` the stone-filled box to extract water which has seeped into the box. With this device, however, the conduit is laid on the bed oE stone discharged from the stone-filled box. Consequerilly, if the trench is qnite deep or iE the water table is qu;te high the sides of the trench may collapse or water may seep into the trench and the bedding layer before conduit can be laid.
Despite the development of various types of devices, trench boots used in conjunction with trenchers, trench boxes, trench hoppers or chutes following plows and other types of devwes, there are some problems that heretofore have remained unsolved. For example, it is extremely difficult to accurately maintain grade and alignment of conduit being laid in a deep trench. In :he past, grade and alignment have been matters of estimation and approximalion by the underground contractor or the worker operating the trenching devices.

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.4s more sophisticated technolo~ becan:e available, it becarne po sible to position and use lasers in the bottom of 8 trench to assist in alignrr.ent and maintaining grade. However, in-trench laser ~ystems cannot always be used to accurately align a conduit or maintain it on-grade, particularly where se~ere conditions exist because water and/or sand r,love into the conauit and deflect or obstr~ct the laser beam.
In ~lnited States Patent ~;os. 4,714,3~1 and 4,7~ 6, issued to G. Br~nt Ha~ch, December 22, 1~,'87 and May 3, 1988, respectively, both entitl~d "Mach.ne For Laying Conduit ~nd Methods For Use Thereof'' a laser transmitter/receiver assemhly is used to maintam conduit being laid on-grade and in alignment. The laser assembly includes a laser transmit~er disposed to transmit an unobstructed sweep signal in a horizontal plane and an alignment beam on a direct line parallel to the alignment desired for the conduit being laid.
A laser receiver, which includes photo cells for sensing the sweep signal, can deScrmine whether the bottom of the trench is maintained on grade. The signal fro;n ~he laser receiver is used to actuate a hydraulic valve which, iD tarn, can control a levsler gate which can modify the grade by increasing or decreasing the amount of fill material deposited below the conduit. Alignment is controlled by a target mounted on the top of or above th~. apparatus maintained in the direct line of the alignment beam. When the alignment beam strikes the target it provides a visual display that enables the operator to adjust the alignment according to the degree of displacement of Ihe alignment beam from the center of the target. A
problem with the afore ~entioned approach is that the alignment of the conduit is made on the basis of an observatior. :-i a target mounted on the top of the conduit laying apparalus, which may be some 20 or mo: ::e~ ~bove the conduit being laid. It is possible with this 2 t~ 2 =_ approach to introduce signifieant errors due to both tilting of the boxlike structure from the vertica! as well as lateral shifts to one side or the other from a predetermined line along which the conduit is to be laid, which may ~e due to slight error in the formation of a trench. For example, if the apparatus ;nclines to one side or the other an angle ~ from the vertical the conduit can be offset from the desired aligned path at the conduit level a distance ~ = 12Htan~

where ~ is the error offset introduced at the level of the conduit, in inches, H is the hei~ht of the target above the conduit, in feet, and e is the angle of inclination from the vertical.
For small angles, this can be simplified to ~ ~ 0.21H
where ~ is the error per degree of inclination. Therefore, it will be clear and for a 20 foot structure the conduit can be offset by 4.2 inches for each de6ree of incline. Althou~h the Hatch machine has a tilt indicator small angles of tilt are difficult to observe, and a five de6ree tilt of a 20 foot st.ucture could easily provid over a 20 inch displacement error to either side of the aligned position or a total deviation between e~tremes of over 40 inches.
Clearly, this is an unacceptable margin of error. Lateral shifts of the box can also produce errors in the placement of the conduit unless such shifts are detected anl compensated hy adjustin6 the positions of the conduit settin6 tracks.
Also, the normal procedure for conduit layin6, as outlined in Ihe "Cnlerpill.lr Equipment Performance Guide Book" is for an excavalor IO dig a porfit)n of Ihe trench and - `, 2 ~ 7 ;

then to sit idle while the conduit is set. Once the conduit is set, the excavator commences digging on the next portion of the trench. With thij procedure, the excavator is actually dig~ing only aboul half the time.
The handling of the conduit itself has also presented problems. Where the conduit is heavy cement sewage pipe, it is difficult for one worker to lower the pipe into the trench, or to position the pipe, par-dcularly when the trench is rather deep. When the pipe is flexible pipe it is critical that the pipe be delivered to the bottom of the trench in a manner which will not kink or damage the pipe. Since different types of pipe or conduit present different types of problems, heretofore there has not been a trench contractor to simul~aneously lay two types of conduit, namely flexible and ri~id conduits.
Thus, although there have been a number of developments in trench boots and boxes which assist in the laying of conduit within a trench, iî would be an improvement to provide an apparatus in which laying subterranean conduit under a variety of ground conditions would be efficient and economically justifiab;e. It would be an improvement to provide a structure which could be separated quickly and easily to avoid obstacles such as utility lines within a trench while still permitting conduit to be laid with the assistance of that structure in the vicinity of and beneath the utility line. It would be a further hnprovement to provide an r,perations-efficient apparatus which can be operated to si~nificantly reduce the amount of earth that must be excavated from and back filled into a trench, and which requ,res a mlnimum of large excavating equipment, and permits such excav;llin~ equipment to he en~a~ed in the trench-di~ging function almost continuously. It would he anolher improvement to provide an apparatus which would h;~ve dewatering cap;lhility to assist in Il 2 ~ c~

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the laying of conduit in areas vith high water tables. It would bc still another improvement to provide a conduit lowering system which would automatic~lly deliver and align conduit within the trench. It would be a further improvement to provide an improved grade and alignment system, heretofore not p~ovided with trench boxes~ which would increase the operator's ability to accuractely maintain the apparatus on-grade and in alignment. It would be another improvement to provide an apparatus which would p~rmit more than one type of conduit to be laid in alignment and on-grade simultaneously. It would he still another improvement to provide an apparatus which dispenses the exzct amount of fill material desired into the trench at the proper time and place, thereby eliminating waste of labor, material and equipment time.
OBJECrS AND BRIEF SUMMARY OF THE INVEI~'TION
In view of the foregoing needs and probtems experienced hy underground contractors and workmen in laying conduit within a trench which make trench boots and trench boxes desirable, it is a primary object of the present invention to provide an improved trench boot apparatus in which an improved grade and alignment system is provided to assure that the conduit is laid in ali~nment and on-grade with a much higher degree of accuracy than heretofore available.
It is another ohject of the present invention to provide an apparatus as in the lasl ohject for the laying of conduit within a trench that can be separated quickly and e.lsily to avoid u~ility lines in a trench while still providin~ apparatus to assist in the laying of conduit in the trench.
A further ohject Of the present invention is to provide an app.lr.ltus of tne type under ~ 2aQ,~q~

discussion for laying conduit within 3 trench in which a dewatering system is provided for extractin~ ground wa~er which seeps into thc apparatus.
Yet another object of the present invention is to provide an apparatus as aforementioned for laying conduit within a trench in which a mechanism is provided to assist in the lowering of conduit into she trench for positioning in alignment and on-grade.
Still another object of the present invention is to provide an apparatus as in the previous objects for laying conduit within a trench which enables the underground contractor to simultaneously lay different types of conduit.
A further object of the present invention is to provide a sturdy apparatus as suBgested by the previous objects for the laying of conduit within a trench and for shoring up the walls of the trench thereby providing safety to the workers within the trench and preventing damage to the conduit caused by collapsing trench walls.
Another object of the present invention is to provide an apparatus of the type under consideration which can be separated into easily stackable components thereby facilitatin~
easy transport of the apparatus from one job site to another.
The foregoing objects are accomplished by the apparatus of the present invention which is used for laying conduit within a trench and which comprises a boxlike structure having side walls and end walls. The boxlike structure has internal compartmçnts and is separable into an upper portion and a lower portion. In one embodiment the compartments comprise at least a fill bin compartment for receiving fill material and dispensing the fill ma~erial on the bottom of the trench, and a conduit laying compartn1ent partially open a its lop and boltom through which conduit is lowered and positioned.

- 2~j$-~3~2 One embodiment of the apparatus of the present inveDtion is advanced through tbe trench by use of a tow bar rigidly mounted to the forward cnd wall of ~he boxdike structure.
In another embodiment a wire ropc loop is also similarly mounted. The tow bar is spaced from the foJward end wall by mounting brackets thereby enabling the bucket of a backhoe or other excavator to grasp the tow bar and maneuver the boxlike structure by applying pulling, upward or downward force upon Ihe tow bar and/or forward wall of the boxlike structure. Si nilar!~, the wire rope loop allows somewhat the same movement control. This configuration for the tow bar allows the excavator to quickly attach itself to and maintain positive control of the boxlike structure, and to release quickly so as to recommence excavation. In this manner, the boxlike structure of one embodiment can be lifted or lowered while advancing the boxlike structure to make adjustments necessary to maintain it on-grsde.
An assembly by which the upper portion of the boxlike structure is secured in nesting engagement to the lower portion of the boxlike structure is provided so that the upper portion rests perfectly aligned and tlush with the lower portion. The assembly comprises a series of transverse rods extending below the lower edge of the upper portion of the boxlike structure. The transverse rods are connected to the upl,er portion by U-shaped brackets which nest in, and register with, U-shaped cups mounted within the lower portion of the boxlike structure. Latches are provided to secure the lower portion to the upper portion.
- In one preferred embodiment of the present invention, the boxlike structure has an angled nose which extends forward inclinin~ downwardly to a cutting edge and is located on the lowel portion of the boxlike structure. This an~led nose assists in shearing ~he bottom 3 ~

of the trench on~grade, and pro~rides an incline upon which thc tow bar can be conveniently mounted for easy access by an excavating implement. l~e freshly sheared bottom of the trench is ready to receive fill material at whatever uniform thickness is desired. Thus, there is no need to overexcavate the trench to assure a proper bed of fill material.
In another preferred embodiment of the present invention, the boxlike structure has a nose section which extends forward but does not incline to a cutting edge. ~ather, a shearing blzde is adjustably mounted to the nose section such that the shearing blade may be adjusted upward or downward. Thus, as the boxlike structure is pulled forward, the shearing blade may be adjusted upward or downward such that the freshly sheared bottom of the trench is maintained on-grade. furthermore, the upward or downward adjustment of the shearing blade may be automatically accomplished by a hydraulic actuated level system controlled by a laser level detectlon system, to be discussed hereinafter.
With another preferred embodiment of the present invention, the boxlike structure has an enclosed compartment with a floor which extends from the nose to the point at which fill material is discharged from the fill bin compartment into the trench. This enclosed compartment provides a water collection area to assist a dewatering system in removing ground water which seeps into the boxlike structure. Vent openings in the enclosed compartment permit ground water to flow into the enclosed compartment where a pump Qr suction screen can be used to extract the ground water which accumulates within the enclosed compartment. also, the enclosed compartment may comprise a feed tunnel whereby tlexible conduit can be fed into the feed tunnel for discharge into the layer of fill material near the floor of the enclosed compartment. Thus, nexihle conduit can be fed 2 ~ ' 2 . . _.

through the enclosed compartment to disposition at the bottom of the trench within an envelope of fill material while other conduit is being simultaneously laid on top of the fill material bed.
Several additional features can be provided for the apparatus of the present invention which assist in the laying of conduit in aligDment and on-grade. The apparatus may further comprise a leveler gate whicb strikes off the fill material at a predetermined trench depth.
It is preferred that this leveler gate be automatically operated to adjust its position to compensate for movement off-grade. Movement off-grade is detected by use of a laser transmitter disposed outside the trench which provides a beam received by a laser rereiver mounted on the apparatus of the present invention. The laser receiver determines if the apparatus is off-grade, and if so, it actuates a mechanism which causes the leveler gate to raise or lower accordingly.
ln all preferred embodiments, an important feature of the invention is Ihat the laser transmitted also ,.rovides an aiignment beam which strikes a target mounted on the apparatus. Ali)!nment means is provided which comprises a laser transmitter disposed to provide a substantially horizontal alignment laser beam arranged in a vertical plane extending through the path along which the conduit is to be laid. Reflecting means is provided on said boxlike structure for intercepting and reflecting said alignment laser beam within said vertical plane in a substantially vertical direction toward the conduit being laid.
Indicating means is provided withirl said plane proximate to the conduit for intercepting said alignment laser beam and providing an indication of alignment or misalignment of said alignment laser beam from said path as a function of the deviation of said reflec~ed 2~QQ~ ~2 alignment laser beam from a prcdetermined refcrcncc poin~ on said indicating means. In all preferred embodimem~s, a weighted pendulum means is provided on which a mirror is mounted for maintaining the orientat;on of said mirror independently of the degree of tils of said boxlike structure thereby assuring that said reflected ali~nment beam remains vertical regardless of the degree of tilt. The operator of the apparatus watches the ~arget for a visual display of w~rether the apparatus is in alignment and on-p,rade. To make adjustrnents, the operator causes the bucket of the excavating implement to apply upward, downward or lateral force at the tow bar to compensate for any misalignment or to correct for the distance off-grade.
In the embodiment incorporating an automatically adjusted shearing blade the laser transmitter and receiver system provides a control signal proportional to the distance that the boxlike structure is off-grade. The control signal is translated into movement of the adjustable shearing blade, either up or down, in order to keep the structure on-grade. The translation of the control signal is accomplis'ned by a hydraulic ram and lever arrangement.
Another feature that can be provided is a fill material notcher which provides a notch in the surface of the fill material bed being laid on the bottom of a trench to accommodate the bell end of a conduit having a bell. A notching gate is provided which carves into the fill material to create a notch. It is preferred that the notching gate be mounted on the leveler gate and that it be automatically operated to place the notch in the proper position.
To accomplish this a roller arm is provided which travels the top surface contour of a previously laid conduit section. When the roller arm encounters the bell of the previously laid conduit a signal actuates the notching gate to extend it helow the leveler gate ~herehy 2 ~ ~ ~ ?~ 2 carving a notch in the fill material. The notch in the fi!l material is thus positioned to accommodatc the bell of the next conduit to be positioned at the bottom of the trench.
A further feature of the present invention that can be incorporated into one of the preferred embodiments to accommodate conduit or pipe having a bell is a two level conduit support rail system. In thc two level pipe support rail system two individual lengths of pipe or conduit are supported from off the floor of the boxlike structure. The first length of pipe is supponed by pipe support rails at a lower level than ~he level at which the second length of pipe is supported. This difference in level 8110ws the bell of the first length of pipe to properly align with the second length of pipe as both are laid in the bottom of the trench.
Still another feature of the present invention incorporated into one of ~he preferred embodiments is a conduit lowering assembly which lowers the conduit into the boxlike structure in a manner such that i~ is aligned and readied for setting with previously laid conduit. The lowering assembly comprises a grasping mechanism which grasps a conduit section to be lowered into the apparatus. The grasping mechanism comprises a guide tube within which a sliding member is disposed. A clamp which grasps the barrel portion of the conduit is connected to the guide tube. The sliding member has a hook end which supports the bell portion of the conduit. Once the grasping mechanism is lowered into the boxlike structure, it can be advanced rearward into setting engagement with the previously laid conduit either manually or by a push arm which engages and pushes the bell portion of the conduit. As the conduit is being pushed forward the sliding member slides within the guide tuhe, the clamp is released, and the hook is released ~rom its supporting engagement such that the grasping mechanism can be removed from the conduit without disturbing she 2 ~ 7 2 ~ ?

positioning of the conduit.
The grasping mechanism is lowered into the boxlike structure of the apparatus by a lowering mechanism comprising venical rails in which a support structure moves vertically upward and downward. The support structure has support arms upon which the grasping mechanism is placed. By placing the grasping mechanism in notches provided in the support arms, the conduit is centered and aligned with the previously laid conduit.
The apparatus of the present invention provides the underground contractor with tremendous versatility. The apparatus can be used in stable or unstable earth and can significantly reduce the time it takes to lay conduit in rocky ground, ground with a high water table, or ground containing utility lines. Under stable ground conditions, the apparatus provides shoring walls to protect workers from collapse of the trench walls and a self-dispensing system for the rapid delive~y of a fill material to the bottom of the trench. Under unstable ground conditions, the operator of the apparatus need only clear away sumcient eanh to enable ths operator to pull the apparatus forward. The angled nose cutting edge or the adjustable shearing edge assist in shearing the trench to its proper depth. With regard to ground conditions having a high water tab!e, the walls of the boxlike structure prevent ground water from seeping laterally into the conduit laying area. Further, the floor provides a barrier to the ground water which enables the operator to lay a uniform layer of fill material on the bottom of the trench before there is an opportunity for waler seepage.
Also, much of the water that may eventually seep into the boxlike structure passes through .. ~
ven~ openings into the enclosed companment from where it can be collected and pumped from the bottom of the trench.

~ r r ~ 2 For conduit being laid in areas having utility lines, thc apparatus of the present invention is particularly useful. The excavator clear~ the earth from around thc utility line.
A fill material shut-off gate is closed to prevent spillage of fill material from the upper portion of the boxlike structure. Then the latches securing the upper portion of the boxlike structure to the lower portion sre released so that ~he upper portion may be lifted from the lower portion and removed from the trench. The lower portion then can be pulled beneath the utility line. This lower portion provides shoring walls and a work area to facilitate the laying of conduit on the bottom of the trench beneath the utility line. After the utility line has been cleared, the upper portion of the boxlike structure may be repositioned squarely on top of the lower portion and secured thereto for further installation of conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete unders!anding of this invention, reference should now be made to the embodiments illustrated in greate,r detail in the accompanying drawings and described below. In the drawings:
Figure I is a perspective view of the apparatus of the present invention wherein a portion of the trench wall is cut away to show the apparatus, a hackhoe bucket engaging the tow bar portion of the apparatus, a front end loader back filling the trench, and the disposition of a portion of the grade and alignment maintenance system;
Figure 2 is a perspective view of the apparatus with a portion of the side wall cut away so that the various features internal of the apparatus can be shown in their relative disposition to each other;
Figure 3 is sn elevational, lon~i~udina] secfion view of the apparatus showing the 2 ~ r~

relative disposition of various features within the onc embodiment of the preser.t invention;
Figure 4 is a perspective view of the apparatus vith the upper portion thereof being lifted clear of the lower portion and showing the mechanism by which the upper portion aligns and nests squ~re]y in the lower portion Figure S is an enlarged cut-away view along line 5~5 of Figure 4 showing an engagemen~ member in register with a receiving member and a lalch used to secure ~he upper portion to the lower portion of the apparatus;
~ igure 6 is an enlarged perspective cut-away view along line 6-6 of figure 4 showin~
the fill material shut-off gate of one present embodiment;
Figure 7 is an enlarged cut away view of a tilt indicator mounted on the forward end ~;
wall of the apparatus of the present invention;
Figure 8 is an enlarged perspective cut-away view showing vent openings on an interior transverse wall near the bottprn of the apparatus and also showing the discharge end of the flexible conduit feed assembly with a flexible conduit being dischar~ed therethrough;
Figure 9 is an enlarged perspective cut-away view of the apparatus viewed from the rear in which a side wa11 is partially cut away to show the conduit lowering assembly lowering a section of conduit for alignment and setting;
Figure 10 is an enlarged perspective view of the grasping mechanism used in the conduit lowzring assembly showing a conduit in grasping engagement;
Figure 11 is an enlarged perspective view of the grasping mechanism used in the conduit-lowering assembly showing the clamp of the grasping means being released;
Figure 12 is a perspective view of an alternative embodiment of the present invention with tt ~idc ~nd end w~ll partialb cut away lo illustrate the irlternrll component~ :hercof;
Flgurc 13 ig a perspectlve view of ~nother presently prcferrcd embodJment of thc prcsent invention w,herein a portion of the trench wall i3 CUt away to show thc apparatus;
Figure 14 is 8 perspective view of the emoodiment shown in Pigure 13 w~'th thc side wall cut sway so that the vsrious festures internal of thc apparatus can b~ shown;
Figure IS is a top view showl'ng ;n greater detail thc condu;t support system of the embod;ment shown in F;~ure 13;
Figure 16 ;s a perspective v;ew showing thc mechanism used to adjust the level of the condu;t support system shown in F;gure IS;
F;gure 17 ;s a perspect;ve v;ew show;ng another portion of the p;pe support systern shown ;n Figure 15;
Figure 18 ;s a perspect;ve view showing in dctail the p;pe setting mechanism of the embod;ment ;llustrated ;n F;gure 16;
Figure 19 ;s a top plan v;c~v of a schemat;c of a travcrse assembly for slidsbly support;ng a narrow reflect;n6 m;rror for intercepting a laser beam and red;recting it downwardly ;nto the boxlike structure where the condu;t ;s being laid, and illustrating a pendulum arrangement for ma;ntaining thc m;rror aligned w;th the laser beam to compensate for tilt and lateral sh;fts of the boxl;ke structure;
,FJ'gure 20 is a side elevational v;cw of the pendu1um mechanism shown in Figure 19, illustrating the details of a brake'adjustment or damper for damping thc oscillations or . . .
swin~s of thc pendulum: .

Figure 21 is a diagrammatic side elevational view of the boxlik. structure in 2 ~ a 3 2 . .

aceordance wilh Ihe present invenlion, showing a pendulum and reflecfing mirror ~sed to insure alignmenl of Ihe conduit along a desired palh or direction;
Figure 22 is similar ~o Figure 21 bul showing an allernate form of reflecling mirror and support slructure used withoul the traverse assembly of ~igure 19;
Figure 23 is a diagrammalic rear elevalional view of the arrangement shown in F igure 22;
Figure 24 is a side elevational view which illuslrates diagrammalic 'y some delails of he pendulurn structure used in Figures 22 and 23; and Figure 25 is a diagrammalic rear elevational view of Ihe ar an~ement shown in Figures 22-24, illustrating the manner in which Ihe reflecling mirror is always mainlained horizonlally independenlly of Ihe till of Ihe boxlike slructure thereby insuring Ihal reflecled beams are always reflected vertical~y dowm lrdly toward the conduit.

DETAILED DE$CRIPTION OF THE PREFERRED EMBODIMEI~ITS

Referring now specifically to Ihe drawings, wherein like numerals indicate like parls ~hroughout, the apparalus for laying conduit within a trench in generally desi6naled 10 and eomr,rises a hoxlike slruclure 12 having forward and rear end walls 14 and 16 and side walls 18. The boxlike slruclure 12 is configured lo separate inlo an upper porlion 20 and a lower portion 22. Of course, il should he underslood thal Ihe hoxlike structure 12 may separ.l~e into more Ihan two ponions, such as illuslrated in Figure 12 wherein an intermeditlte portil)n 24 is illuslraled ~ ~ ~ r ~ !~

As shown particularly in Figures 2 and 3, thc boxlike structure 12 further comprises internal tr~nsverse walls which define compartments within the box]ike structure I2. The boxlike structure 12 has a fill bin compartment 34 internal of the boxlike structure 12 for receiving fill material 36 and dispensing the fill material 36 on the bottom of a trench and a canduit laying compartment 38 which is the area in which conduit ;s fed for aligm~lent and positioning at the bot;~m of a trench. In one of the preferred embodiments of the present invention, as illustrated in Figure 2, the fill bin compartment 34 is defined by an interior fill material side wall 26 and an interior fill material bin wall 28. The inlerior fill material bin wall has a hopper portion 30 and a chute portion 32. In another preferred embodiment Or the present invention illustrated at Figure 12, the boxlike structure 12 has only one in;erior transverse wall, the interior fill material slide wall ~6 and the rear end wall 16 serves as the hopper portion and chute portion for a fill material bin wall.
The boxlike structure 12 further comprises a tow bar 40 mounted on the forward end wall 14. The tow bar 40 is disposed in brackets 4' which are ri~idly mount~d on the for vard end wall 14 of the lower portion 22 of the boxlike structure 12. The tow bar 40 is spaced from the forward end wall ~4 sufficiently to receive the teeth of a bucket 44 of an excavating implement 46 suhstantially as shown in Fi~ure I When the bucket 44 of an excavating implement 4fi ~e ~Q. a backhoe) ~rasps the tow bar 40 in the manner illustrated in Fi~ure 1, the opcrator of ihe excavatin~ implement 46 can apply downward force a~ainst the end wall 14 while simultuneously pullin~ ()n the tow b"r 4() to adv;3nce the hoxlike slruclure ]2 wilhin Ihe Irench, Iherthy lowerin~ the hoxlike structure ~2 wilhin ,1 Irench 4X. LiflinL~ lorce muy he applied to lift Ihe l-oxlike s~ruc~ure 12 wi~hin ~he Irench 4X hy curlin~ Ihe huckcl 44 in 2 ~, n i~J; ~ '^,!

about the tow bar 40 and pulling up on the tow bar 40 while pulling force is applied agains~
the tow bar 40 to advance the boxlike structure 12 wjthin the trench 48. It has been found that the tow bar configuration illustrated and described herein enables the operatnr of the excavating implement 46 to maneuver the apparatus for laymg conduit 10 within the trench 48 wilh remarkable on-grade precision because he can apply vertical longitudinal and lateral forces as needed to maintain grade. Thus the task of maintaining the boxlike structure 12 positioned so that conduit can be laid on-grade and in alignment is appreciably assisted by the tow bar configuration.
The boxlike structure 12 further comprises features for securing the upper portion 20 to the lower portion 22 in an aligned and flush engagement. The features also permit the releasable attachment of the upper portion 20 to the lo. wer portion 2. These features include engagement members 50 receiving members 52 and latches 54 which will be described with more particularity hereinbelow.
Turning now particularly to Figure 1 the apparatus for laying conduit within a trench 48 is illustrated within the trench 48. An excavatinfg implement 46 such as a backhoe clears the earth away from the forward end of the boxlike structure 12. The e~cavating implement can then grasp the tow bar 40 and pull the boxlikc structure 12 forward within the trench 48.` When fill material 36 is disposed within the fill bin compartment 34 as ~he boxlike structure 12 is advanced forward a layer of fill material 36 is deposited on the floor of the trench 48. Conduit (now shown) is lowered into the conduit laying compartmen~ 3X for positif ning on the laycr of fill m~terial 36 in alignmf nt and on-gr;~de. T he lowf ring and -o~itif~ning of the condui~ ~ithin the trench can he done manuillly or with the assist.lnce of - ` 2 ~ 3 ) ~
, . . ~=_C. . .

conduit-setting system, while thc excavating implement con~inues to excavate the trench 48 forward of the boxlike structure 12. Obviously, if a v.orker is posi~ioned within the conduit laying compartment 38, the side walls 18 of the boxlike structure 12 protect the worker against the collapse of thc trench walls.
As tl1e boxlike structure 12 is advanced within the trench 48, it is preferred that a small loader 56 fill the fill bin compartment 34 with fill material 36 as needed. Thus, the excavating implernent 46 is free to excavate trench 4~ and advance the boxlike structure 12.
There is no particular need to provide additional heavy equipment. The same small loader 56 can promptly back fill the trench 4~, as shown in Figure 1.
It has been determined that with most ground conditions, the apparatus lû of the present invention enables the underground contractor to move less than half the material tha~ is normally requircd during trenching operations. Thus, there is correspondin~ly less than half the material to be back filled into the trench 48 once the conduit has been set, Because material movement has been minimized, the trenching operation advances more rapidly. Also, since the excavating implement 46 does not lay idle while conduit is bein~ set w.thin the trench 48, but it is used to excavate the trench 48 in advance of the boxlike structure 12, the excavatin~ impiernent 46 is being used continuously and much more effi~iently. These efficiencies significantly increase the amount of conduit that can be laid in a trench 48 per day. On any project for layin~ subterranean conduit, this can mean drastic savin~s in equipment rental costs and labor costs.
In order to insure that ~he conduit is laid in ali~nment and on-~rade, a preferre~
emhodiment of the present invenlion also comprises a grade mainteniance assemhly. Th~

~rade maintenance assembly compris~s a laser transmitter 5~ which transmits signa]s to a laser rece;ver 60 which dctermines the depth of thc trench 48 a~ the point wherc conduit is being laid. In one preferred embodiment, ~he laser transmitter 58 transmits at least two types of signals, a sweeping signal 62 which is received by the laser receiver 60 and an alignment si~nal or beam 64 which strikes a target 66 mounted on the boxlike structure 12 and reflects the beam downwardly, as su~gested in Figures 1-3 and 12-14. The manner in which the ~rade and alignment maintenance assembly operates is described with more particularity below.
In Figure 2 a preferred embodiment of the present invention is shown in which the relative disposition of the internal cornponents are illustrated. In this preferred emhodiment, the boxlike struc~ure 12 has an angled nose portion 68 and a floor 70. The angled nose portion 68 inclines downwardly to a cutting edge at the hottom of the boxlike structure 12.
The angled nose portion 6~ and noor 70 assist in shearing on-grade the bottom oî the trench 48 to maintain the boxlike structure 12 on-grade. Since the bucket 44 of the excavating irnplement 46 is used to apply force on the forward end wall 14, it is preferred that gussets 72 be provided so that the structural integrity of the angled nose portion 68 is maintained.
A preferred embodiment, as illustrated in Figure 2, further comprises a flexible cffnduit feed assembly 74 having ab inlet 76, a feed tunnel 78 and a plate ~n with a dis. harge sleeve 82. The feed tunnel 78 may he separated at junction 84 (as shown in Fig. 3) lo accommodate she separa~ion of the hoxlike structure ]2. The lower portion of the feed tunnel 78 has a flared end 86 which receives the upper portion of the tunnel 78 so tha~ when flexible conduit is fed through the feed tunnel 78 it will not snag or hang up within the feed tunnel 78.
Also illustrated in the preferred embodiment shown in Figure 2 is a fill material shut-off gate 88 which is operated by a ram 90. As shown at Figure 6, the fill material shut-off gate 88 rests on channel braces 154 and beneath angle braces 89. The ram 90 operates to move the fill material shut-off gate 88 in a longitudinal reciprocating motion between open and closed positions. When the fill material shut-off gate is open, it permits fill material 36 stored within the fill bin compartment 34 to slide down the interior fill material slide wall 26 to the bottom of the trench 48. When the upper portion 20 of the boxlike structure 12 is separated from the lower portion 22, it becomes necessary to close off the upper portion of the fill bin compartment 34 so that fill material 36 is not spilled into the working area.
To accomplish this, the ram 90 pushes the fill material shut-off gate 88 forward to its closed position.
The forward end wall 14, the floor 70, the side walls 18 and the interior fill material slide wasll 26 define an enclosed compartment 92 for the preferred embodiment illustrated in Figure 2. The enclosed compartment 92 houses a dewatering system for the apparatus for laying conduit 10. The dewatering system comprises a plurality of vent openings 94 and a water collection and discharge assembly 96 which collects ground water which accumulates through seepage within the enclosed compartment 92 and removes it from the boxlike structure 12 for discharge remote from the trench 48.
In one preferred embodiment the fill material 36 is struck off as it is dispensed from the fill bin compartment 34. Striking off of fill material 36 is accomplished by a leveler gate 98. The leveler gate 98 is operated in its vertical movement by a ram 100 and a laser 2.~Q,1~2 ,.

rcceiver mast 102 vhich communicates with thc laser receiver 60. In thc preferred embodiment illustrated, the laser receiver mast 102 comprises a push rod 104 which enga~es a shoulder 106 connected to the upper mast rod 108. The upper mast rod 108 is held in position adjacent to the side wall 18 by guide mounts 110 and a nub 112 prevents the upper mast rod 108 from falling through the guide mounts 110 when the upper portion 20 of the boxlike structure 12 is detached and lifted from engagement with the lower portion 22.
Attached to the leveler gate 98 can be a notching gate 114 which is used to carve a notch 194 in the layer of fill material 36 to accommodate the bell of a conduit. The notching gate 114 is acluated by an assembly comprising a roller arm 116 connected to a sensing ram 118 which communicates to a responsive ram 120 which is mounted between the notching gate 114 and leveler gate 98. The roller arm 116 is designed to travel the contour of the upper surface of a conduit 125 (as shown in Figure 3) so that any changes in the contour are communicated to the sensing ram 118 which conveys that change in contour via tube 122 to the responsive ram 120. The responsive ram 120, then in response to the signal from the sensing ram 118 actuates the vert;cal movement, either up or down, of the notching gate 114. As shown in Figure 2, the leveler gate 98 and notching gate 114 are disposed within guide channels 124 which permit the vertical sliding movement of the leveler gate 98 and notching gate 114.

.. .
In order to lower the condl~it 12~ into the boxlike structure 12 of the preferred embodiment illustrated in Figure 2, a conduit lowering assembly 12fi is provided. The conduit lowering assembly 126 comprises a grasping mechanism 128 and a conveyance mechanism 130. The grasping mechanism ~28 is used to grasp and hold securely a conduit 2~f' 12 125 for safe lowering into the trench 48. The 3rasping mechanism 128 comprises a guidc tube 132, a sliding member 134 and an eycle~ 136 use~ to suspend the grasping mechanism 128 during raising and lowering of the conduil 125 onto support arms 142 of the conveyance mechanism 130. The conveyance mechanism 130 comprisej a pair of rails 138 secured to ~he inside of one of the side walls lR of the boxlike structure ]2 and a lowering member 14() comprising support arms 142, a support plate 144, and rollers 14~ which permit movement of the lowering member 140 vertically within the conduit laying compartment 3X.
A primary feature of the preferred embodiment of the apparatus 10 of the presen~
invention, is its separability into an upper portion 20 and a lower portion 22. This separability introduces tremendous versatility to the apparatus 10. The separation of the boxlike structure 12 facilitates transport of the apparatus 10 because the upper portion 7() and lower portion 22 can be laid on their sides and stacked one on top of the other on a flat hed trailer that can be easily towed by a pick-up truck. This enables transport without any problems due to the limited heights of highway with overpasses or underpasses and ulso facilitates the storage of the apparatus 10 because it can be placed on a trailer and transported to a stora~e facility.
The assembly and disassembly of the apparatus 10 can be accomplished rapidly and wlthnut any complexity. When assembling the apparatus 10, the upper portion is always assured of properly square ali~nment hecause the en~a~ement memhers 5() are confi~ured to re~ister with the receiving memhers 5~ h)r nesting en~aBement. As illustrated in Fi~ure 4, the upper portion 20 of the hoxlike structure 1~ can be lihed from or lowered onto the lower portion 22 using cables l~s connected to the bucket ~4 of the excavatin~ implement ~ t, t~ . 2 46. Cables 148 are drapcd over a hook 150 on the bucket M and secured to the upper portion 22 at lifting ears 152. When suspended as shown in Figure 4, a worker can easily maneuver the suspended upper portion 20 laterally or longitudinally so that the engagement members S0 align ;n register with the receiving members 52.
As best shown in Figure 5, the upper and lower portions 20 and 22 have channel braces 154 attached at the edges of the upper snd lower portions 20 and 22. Mounted on the channel brace 154 for the upper portion 20 are the engagement members 50 which comprise a trans-~erse rod 156 mounted between brackets with a U-shaped portion 158 which extend below the lower edge of the upper portion 20 of the hoxlike structure 12.
Mounted on the channel brace 154 of the lower portion 22 of the boxlike structure 12 are the receiving members 52 which comprise a U-shaped cup ]6n. When the upper portion 20 is properly aligned, the U-shaped cup 16Q. When the upper portion 20 is properly aligned, the U-shaped portion of the brackets 158 nest in the U-shaped cups 160 as shown in Figure 2. Latches 54 can then be secured to prevent the upper portion 20 from movement with respect to the lower portion 22. The latches 54, as best shown in Figure 5, are preferably a lever and catch assembly having a lever 162, a catch 164 and an adjustable connector 166 which engages the catch 164 in securing engagement. Although the preferred embodiment is a lever and catch assembly, it should be understood thia~ other types of lo~cking or securing means may be used.
When lifting the upper portion 20 from the lower portion 22, the latch 54 is disengaged, cables 148 are draped over the hook 150 attached to the excavating implement bucket 44 and secured to lifting ears 152. If there is some material 36 in the fill bin ~,I',J'`S~ ' 2 compartment 34, thc fill materisl shut~off gate 88 is closed so that no fill matcrial 36 will spill from the compartmenl 34. Then, the bucl~et 44 lif s the cables 148 attached to the upper ponion 20, thereby lifting the upper portion 20 from the lower portion 22.
This feature is particularly useful during the conduit laying operation when an obstacle such as a utility line is encountered. In such instances, the boxlike structure ]2 is pulled near the utility line and the upper ponion 2Q of the boxlike structure 12 is removed and lifted out of the trcnch 48, thereby permitting clearance of the lower portion 22 beneath the utility line. The laying of conduit 125 can recommence using only the lower portion 22 of the boxlike structure 12. Of course, some of the features are not availahle when using only the lower portion 22. However, the use of the lower portion 22 significantly aids the Iaying of conduit 125 beneath the utility line. A considerable amount of time savings is afforded by using this procedure because with the lower portion 2' remaining in the trench 4~, the amount of eanh required to be removed in slopins back the trench walls is significantly reduced and use of the lower portion 22 still enables the operator to lay a uniform layer of fill material 36 on the bottom of the trench 48.
Once the lower portion 22 of the boxlike structure 12 clears the utility line, the upper ponion 20 can be lowered back into the trench 4~, aligned, sguarely seated, and secured in nesting engagement with the lower portion 22 so that normal conduit laying can commence.
It should be understood that where the boxlike structure 12 is equipped with multiple separations (see, for example, Figure 12), thc boxlike structure 12 can be separated at any of these separations to avoid an obs:acle.
During use of the apparatus 10 of the present invention, ground water may seep inlo n)~2 the trench 48 from thc water tablc. Ground water seepagc problems are psrticularly prevalent when ~t trench boot, such as the apparatus 10 of ~he present invention is parked within the trench 48 for any substantial period of time, such as overnight. If a sufficient amount of ground water seeps into the area of the conduit laying com?artment 34, it can cause significant problems with the condui~ laying operation.
With one preferred embodiment, ground water seeping into the boxlike structure 12 is permired to pASS through the interior fil1 material side wall 26 at vent openings 91 as shown in Figure 8. Ground water passing through such vent openings 94 accumulates within the enclosed compartment 92. The ground water accumulating in the enclosed compar~lner:t 92 can be collected and withdrawn from the boxlike structure 12 by using the water collection and discharge assembly 96. As shown in Figures 2 and 3, the water collection and discharge assembly 96 comprises a pump l68 with a suction screen I70 which collects the ground water and discharges it through an exhaust tube I72 which exits a: the rea: of the boxlike structure I2 to facilitate discharge of the ground watcr remote from the trench ~8.
It is preferred that the exhaust tube I72 has a separable coupling I74 whereby the exhaust tube 172 can be separated when the upper ponion 20 of the boxlike structure t2 is lifted from the lower portion 22. It is also preferred that the exhaust tube 172 be enclosed in or integral with a channel support member I7fi which runs along a side wall I8 of the box~ike structure I2 to the point of exit through the rear wall I6 This channel support ..
member I76 provides added stabilizing support to the side ~all I8 A coupling I78 is provided near the rear wall I6 so that a hose or tube can be connected to the exhaust tube l72 which will direct the ground water being discharged to a p oint remote from the trench 2 3 ~, . i 7 2 , 48. Although the water collection and dischar~e assembly ~6 is described herein and shown in Figures 2 and 3 comprises a pump 168 disposed within the enclosed compartrrlent 92, it should be understood that other water collection and slischar~e assemhlies may bc used. For example, the pump 168 may be disposed at a point outside the trench 48 and cnnnected to the enclosed compartment 92 ~ia a suction tube and a suction scJeen ]70.
When laying conduit in an area exhibiting a particularly high water tahle, in which water seepa~e becu.nes a significant'problem, the water collection and discharge assemhly 96 may be operated continually during use of the apparatus 1() so as to extract as much ground water as possible. lt should be understood that a dewaterin~ system similar to thin shown in Figures 2 and 3 could be adapted for use with other emhodiments of the invention.
When possible, and as needed, it would be a tremendous time and cost savin~s to I;.y fiexible conduit and rigiù condujt simultaneously. When done, a sinL~le trench 48 would he excavated. Earth within the trench would be removed and back filled but once, and subsequent location of the conduits, if necessary for repair or replacement, could be easily accomplished. ~ preferred embodiment of the apparatus 10 of the present invention has a flexible conduit feed assembly 74 which provides a feed tunnel 78 through which tlexible conduit 180 can be directed. As the boxlike~structure 12 of the present invention is advanced wh.,in the trench 48, nexible conduit 180 can be continuously fed throu~h the inlet i6 into the feed tunnel 78. The flexible conduit 180 exits the feed tunnel 78 at the dischar~e sleeve 82. In this manner, when fill material 36 is being deposited in ia liayer on the hottom of the trench 48, the flexihle condu,l 180 is enveloped in the liayer ol' I'ill materi.ll 3(~. The d;schar~e sleeve 82 is centra;ly disposed sufficiently aho-e the tloor 7(~ of the ho~like ~ s j!

struc~ure 12 such tha~ fill material 36 is deposited beneath any fladblc conduit 180 being fed into the fill matcrial 36 cmclope 85 shown in Figurc 8. As flexible conduit 180 i~ laid w~thin the envelope of fill m~tcrisl 36, rigid conduit 12S can be simullancously laid on the surfaa of thc fill material 36 laycr.
If a projcct doss not require the simulsancous laying of flexiblc conduit 180 and rigid conduit 125, the plate 80 having the discharge sleeve 82 may be rcmoved and replaced with a flat platc 80. In this manner, fill mater;al ~'; is ~ree to slidc over the flat plate 80 to the botton, of thc trcnch 48.
In the various preferred emhodiments of the present invention, a number of features may be provided which assist the operaSor of the apparatus 10 in maintaining the apparatus 10 in alignment and on-grade. As mentioned above, certainly the angled nosc portion 68 in conjunction with the floor 70 assist in shearing the bottom of the trench 48 and holding Ihe boxlike structure 12 on-grade. Also, as will be described in detail hereinafter, the automatic adjustment of shearing edge so as to shear thc bottnm of the trench on-grade is a great help to the operator. These features also make is necessary to over-excavate the trench 48. Another feature is the tilt indicator 182 which provides a visual indication whether the boxlike structure 12 is heing maintained on the vertical. The tilt indicator 182 comprises a pendulum pointer 184 mounted on the forwa~d end wall 14 of the boxlike structure 12 on 8 pivot pin 186 which permits the pendulum pointed 184 to freely rotate about the pin 186. Markings 188 are provided to assist the operator in determining visually whether the boxlike btructure 12 is being maintained in a vertically upright position.
Another feature which assists in maintainin~ the apparatus lO on-grade a~d in r~ ~

: ., ., .. .. _. _ . _.. _ ~ ~ .. . .

alignment is the laser transminer/receiver assembly briefly mentioned above. That assembly in one embodimer~t comprises the laser ~ransmitter 58, the laser receiver 60, the target 66, the leveler gate 98 and the laser receiver masl 102. With the laser transmitter/receiver assembly, the depth of the trench 48 may be maintained a: a uniform depth by maneuvering the apparatus 10 within the trench by applying lifting or downward forces as needed on the tow bar 40.
In one preferred embodiment, the laser transmitter 58 is disposed in a position where it will remain und sturbed by the excavation and cGnduit laying activity. The disposition of the laser transmitter 58 can be either external of, or within, the trench 48 depending on the dept~l of the trench 48 and the height of the boxlike structure 12. It is important, however, that the signals from the laser transmitter S8 be unobstructed. The laser transmitter S8 provides a swcep signal 62 on a horizontal plane and an alignment beam 64 on a direct line parallei to the alignment desired for the conduit 125 being laid. The laser receiver 60 receives the sweep sienal 62 and can determine via its sensing capability whether the bottom of .he trench 48 is being maintained on-grade, above-grade or below-grade. The laser receiver 60 has photo cells which sense the sweep si~nal 62 and in turn actuate a hydraulic valve (not shown) which is in communication with and actuates ram 100 such that when the sweep signal 62 received indicates that the boxlike structure 12 is below-grade, the ram 100 lifts the leveler gate 98 to compensate for the amount that the boxlike structure 12 is below-~rade. If the boxlike structure I2 is abovc-grade, the laser receiver 60 communicates with ram I00 such that ram 100 extends !eveler gate 98 to compensate for the amount the boxlike structure 12 is off-~rade. As the leveler gate 9B is raised or lowered by ram ID0, the push 2r'.

rod IQ4 attached to leveler ~ate 98 is raised or lowered accordingly. The push rod 1Q4 abuts shoulder 106 which is attached to the upper mast rod lOfS. Movement of push rod IQ4 is transmitted thrDugh shoulder 106 to the upper mast road 108 such that it slides up and down wi~hin guide mounts 110. Thus, the laser receiver 60 attached to the uppermost end of the upper mast rod 108 is raised or lowered the same amount as the leveler gate 98. In (his manner, the laser receiver 6Q is adjusted upward and downward corresponding to the upward and downward movement of the leveler 6ate 98 whereby a uniform trench depth is maintained despite slight variations caused when moving the boxlike structure 12 within the trench 48.
Not only does operation of the grade maintenance features provide accurale on-grade laying of conduit, they also reduce tremendously the amount of fill material 36 that is wasted. Where no angled nose 68 is used to shear off the bottom of a trench 48 nor laser transmitterlreceiver assemblies used to maintàin uniform trench depth, the trenches 48 are frequently over-excavated to assure thal there is a minimum amount of fill matcrial 36 base beneath the conduit 125, It is not unusual for the fill material 36 layer to be a couple of feet thick in some places to assure that a minimum half foot layer of fill material 36 is placed beneath the conduit 125. Such wasting of fill material 36, is time consuming and expensive.
Maintenance of the boxlike structurc 12 in alignment while pullin~ it through the rrench 48 is assisted by a mirror 6Q2, to be more fully described in connection with figures 19-25. The laser trans nitter 58 provides an alignment beam 64 whish ss set parallel to .he alignment desired for the conduit. As the alignment beam 64 strikes the mirror 6Q2, a visual display of the beam nn a target or sensor 654 (Figure 3) inside the boxlike structure ~2 2 ~ r? ~ 2 ~ ... . ~

proximate tD the conduit 125 en~ he operator to adjust for alignment and grade according to the degree of displacement of the conduit laying ~racks, as will be described bclow, Another feature which facilitates maintainiDg the conduit 125 in alignmenl along the surface of the fill malerial 36 is the notching assembly which carves a notch 194 in the surfac~ of the fill material 36 to accommodatc the bell for a conduit 125 As mentioned above, the notching assembb comprises a notching gate 114, a roller arm 116, and a sensing ram 118 connected to a responsive ram 120 by a tube 122 (See Figure 2). In practice, the roller arm 116, having a roller 190 and a delay extension 192, engages the upper surface contour of a prev~ously laid conduit 125, as shown in Figure 3. As the roller 190 engages the bell of the conduit, the roller arm 116 forces sensing ram 118 to contract, and that contraction signals the responsive ram 120 to actuate the extension of notching gate 114.
When exlended as shown, the notching gate carves a notch 194 in the surface of the fill material 36. As the roller 190 travels over the bell, delay extension 192 continues to engage the bell such that an oversized notch 194 is carved in the fill material 36 so as to accommodate the longitudinal movement of a conduit 125 when the conduit 125 is being aligned and set with the next previously set conduit 125. By providing notches as shown in Figure 3, each conduit is maintained as close to level and on-grade as possible.
The conduit lowering assembly 126 of the present invention not only assisted in lowering of conduit 125 into the conduit laying compartment 38 but also assists in maintaining the conduit 12S in alignment as it is positioneJ and set for its final disposition on the surface of the fill material 36 layer. The conduit-lowering assembly 126 comprises 2 ~ 7 ~

a grasping mechanism 128 and a conveyance mechanism 130. The grasping mechanism 128 comprises 8 guide tube 132 within which a sliding member 134 is pro~rided. The grasping mechanism further comprises at leas: o.. clamp ~96 disposed to clamp onto the basrel p~rtion of a conduit 12S. The clamp 196 is attached to the guide tube 132, and it is preferred that clamp 196 have interchangeable jaws 198 to accommodate various sizes of conduit 125. The jaws 198 can be changed by disengaging bolts 200 and replacing one s;ze of jaws 198 with another size and resecuring bolts 200 (see Figures 10 and 11). It is preferred that Ihe clamp 196 be releasable and spring loaded such that as the jaws 198 of the clamp are closed about a conduit 12S a spring holds the clamp jaws 198 snugly against the conduit 125.
To release the jaws 198 from grasping engagement of a conduit 125, means for triggering the release is required; To accomplish this graspinglreleasing function, the spring-loadel~ clamp utilizes an off-center clamping mechanism wherein the jaws 198 of the clamp 196 are held in a grasping position by a spring (not shown) when a clamp roller 202 is disposed in its lowermost position. To achieve this position, a handle 204 is provided whereby a user can manually lock the clamp jaws 198 into grasping enga8ement by swinging the handle 204 to its substantially horizontal locking posilion. To release the clamp 196 the chmp roller 202 is engaged and lifted or the handle 204 can be manually lifted to release the grasping engagement of jaws 198 on thP conduit 125.
The sliding memher has disposed at one end a hooking finger 206 which engages and supports the bell end of the conduil 125. The sliding member 134 has at its other end æ
centering guide 208 comprising curved arms 210 with rolling cylinders 212 which engage the 2~r~

bell portion of the previously laid conduit 125, a bell stop 214 and trigger 216.
ll~c sliding membcr 134 is free to move lon~itudinal~ w~thin guid~ tube 132 until a conduit 125 is grasped ~vithin the grasping mechanism 128. Figure 10 illustrates a conduit 125 just before engagement with a previously laid conduit 125. In figure 10, the hooking fingcr 206 is shown supporting the bell portion of the conduit 125 and the clamp 195 grasping the barrel portion of the conduit 125. As the conduit 125 is advanced towards its setting engagement with a previously laid conduit 125, the sliding member 134 s]ides within guide tuhe 132 such that the trigger 216 engages the clamp roller 202 in lifting engagement as shown in Figure 11. The trigger 216 engages the guide tube 132 thereby preventing any further sliding movement of sliding member 134 within the guide tube 132. When this happens, further advancement of the conduit 125 will release the hooking finger 206 from its s.upporting engagement of the bell portion of the conduit 125. In this manner, the grasping mechanism 128 is completely released from the conduit 125 as that conduit 125 is set and sealed within the next previously laid conduit 12S. To assure a tight and leakproof seal, a gasket 218 is disposed at the connection end of the conduit 125.
Once released, the grasping mechanism 1~8 may be secured in grasping engagement to another conduit 125 in the same manner as previously described.
When the grasping mechanism l28 secures a conduit 125 in grasping engagement, the conduit 125 may be lowered manually into the conduit-laying compartment 138, or as is preferred, a conveyance mechanism 130 may be used to assist in lowering and aligning the conduit 125. The conveyance mechanism 130 comprises a pair of rails 138 and a lowering member 40, which comprises support arms 142, a support plate 144, and rollers 146. The 7 ~

__ lowering member 140 moves vertically as guided by the rails 138. To lower a conduit 125 into the conduit laying compartment 38, the grasping mechanism 128 is positioned to be suspended via a suspension bar 220 which is mounted on the guide tube 132. The suspension bar 220 en~ages center.ng notches 22 in the support arms 142 such that the conduit 125 is suspende~ centrally within the boxlike structure 12 and in alignment with th;
desired alignment fo~ the laying of conduit. The lowering member 140 may be gradually lowered in;o the conduit laying compartment 38 ~ia any cor.ventional manner such as manually lowering the member on a rope or cable, or by use of counterweights, or by a powered chain and sp:oclcet drive, or by using 8 hydraulic ram which would raise or lower the lowe.ing mesnber 140 ;n response to hydraulic signals controlled mamlally.
Thus, to lo.ver a conduit 125 into the conduit layinE compartment 38, the grasping mechanism 128 is secured to a conduit 125 in the manner shown in Figure 10 The grasping mechanism 128 is then suspended on the support arms 142 of the lowering member 140 as shown in Fi&,~re 2. The lowering member 140 is then guided downward by rails 138 to where the conduit 125 .eaches the surface of the fill material 36 or the bottom of the trench 48, as shown in Figure 9. The grasping mechanism 128 is th_n released from the conduit as the conduit 125 is advanced into setting engagement with the next previously laid conduit 125 as shown in Figures 9 and 11. Once released, the grasping mechanism 128 can be lifted from the conduit laying compartment 38 for engagement with another conduit 125 so that the procedure can be repeated.
To advance the conduit 125 into setting engagement with the next previously laid conduit 125, a conduit setter assembly is provided. Such conduit setler assembly comprises Q~ r~ ?~

a push arm 224 with a guide support 226 and a ram 225. The conduit setter assembly operates on a conduit 125 which has been lowered into the conduit laying compartment 38 but has not been set ;n~o the next previously laid conduit. The push s~rm 224 en~ages the bell portion of the conduit 125. As ram 228 contracts, the push anr. 224 slides within the guide support 226 which i5 mounted on a side wall 18 so that the push arm 224 applies u horizoutal pushing force in the direction as shown by the arrow in Fi~ure 9. When a grasping mechanism 128 is used to assist in grasping and lowerin~ ~he conduit 125 into the conduit laying compartment 38, the push urm 224 advances the conduit 125 such that the tri~er 216 engages the clamp roller 202 and relesses the clump 196 and the hooking finBer 20~.
Additional features which ure provided for the hoxlike structure 12 include stiffeners such as the buse stiffeners 230 and the side stiffeners 232 which provide support and rigidity to the side walls 18 of the boxlike structure l2. Also, to facilitate access to the conduit laying compartment 38, a set of step rungs 234 are provided whereby a worker may descen(l into the conduit layin~ compartment 38.
Another preferred emhodiment of the present invention is illustrated in Figure 12.
This embodiment is particularly adapted for layin~ suhstan;ially ri~id plustic pipe within a layer of fill material 36. With this preferred emhodiment, the plastic conduit 23fi is lowered into the conduit layin~ compartment 3~ which is disposed forward of the fill hin compartment 34. The plastic conduit 236 is positioned for its disposition within a layer of till material 36 hy a rockin~ arm assemhly 238. The rocking arm assemhly 238 comprises a pivot pin 240 disposed in pivotin~ enga~ement with a pivot har 242 huvin~ a plurulity Or -` 2~Ir~; ,2 pivot holes 244. By positioning the pivot pin within any one of the pivot ho; ~ 244, the depth of fill matcrial 36 to be disposed beneath the plastic conduit 236 can be adjusted. By way of illustration, if the pivot pin 240 is raised, this would cause more fill material 36 to flow beneath 1he plastic conduit 236 for support. On the other hand, if the pivot pin is lowered, less fill material 36 would support the plastic conduit 236.
The rocking arm assembly 238 fulther comprises a rocking arm 246 which pivots on the pivot pin 240. The rocking srm 246 has a Irough ponion 248 which assists in holding the plastic conduit 236 in alignment. At the distal end of the rocking arm 246 is a roller box 250 having rollers 252 and a housing 254. Attached to the housing 254 can be a thimble 25fi through which the plastic conduit 236 is discharged into the fill bin compartment 34 where the plastic conduit 236 is enveloped in a iayer bf fill material 36.
The plastic conduit 236 is lowered into the boxlike structure 12 substantially as shown in Figure 12 an-~ is directed to its resting position on the rocking arm 246 by a slide 258.
As the plastic conduit 236 drops into position, the bell of the plastic conduit 236 engages touch plate 260 which released the ram plate 262 which is operated by a ram 264 to advance the plastic condu t 236 into setting engagement with the next previously laid conduit 236.
As the boxlike structure 12 of this preferred embodiment is advanced within the trench 48 in a manner similar to that described herein with regard to other preferred embodiments, the plas~ic conduit 236 advances along the rocking arm 246 until another . . ~
section of plastic conduit 236 can be introduced into the line.
To assure that the plastic conduit 236 is laid in alignment and Dn-grade, a grade maintenance assemblv similar to that described above can be used. In the preferred embodimen~ illustrated in Figure 12, a lascr receiver 60 is provided and is disposed such that the laser receiver mast 102 is encased in a fm 266. Althou~h a fin 2OE6 is shown as a preferred embodiment it should be understood shat other configurations for the laser receiver mast and the protection thereof can be used. The laser receiver 60 is in communication witb adjustment ram 268 which raises or lowers the roiler box 250 in response to the signal received by the laser receiver 60. As the roller box 250 is raised or lowered to compensate for deviations from grade, the laser receiver mast 102 is also raised or lowered accordingly.
Fill material 36 can be placed in the fill bin compartment 34 for disposition at the bottom of the trench. A manually adjustable leveler 268 is provided on the rearmost end of the boxlike structure 12 to strike off the fill material 36. Also, a pair of baffles 270 which angle inwardly from the side walls l8 are provided in order to windrow fill materials 36 for support beneath the flexible conduit 236.
Although several of the features with regard to other preferred embodiments are not shown with respect to Figure 12, it should be understood that many of the features are adaptable for usc with the embodiment illustrated in Figure 12. For example, f;ll material shut-off gates 88 can be provided at each of the separation levels in order to shut off fill material 36 from spillage when the boxlike structure is separated. Also, a dewatering system similar to that described above can be incorporated into the boxlike structure illustrated in Figùre 12.
another presently preferred embodiment is shown in Figures 13-18. In the embodirnent shown in Figures 13-18 many of the structures shown are similar nr identical to the structures shown in Figures t-12. Therefore, the operation of the embodiments shown in Figure 13-18 will be similar, or identical, to ~hose cmbodiments illust~ated in Figures 1-12.
Similarly to Ihe earlier described embodimenls, the apparatus for laying conduit within a trench gcnerally comprises a boxlike structure designated 300 in Figure 13 having a forward wall 334, rear 306, and side walls 3~3. The bo~ilike structure 30~ is configured so as to separate in~o an upper portion 302 and a lower portion 304. The seam where upper portion 302 and lower portion 304 separate is designated 310. It should be understood that the boxl;ke structure 300 may be constructed so as to separate into more then two portiI~ns, such as is illustrated in Figure 12 wherein the boxlike structure is separable into three portions.
In a fa!;hion similar to that shown in Figure 2, the cross-sectional perspective iew of Figure 14 shows that the boxlike structure is provided with an internal transverse wall 390 which separates the boxlike structure 300 into two separate compartmer.ts. Boxlike structure 300 has a fill bin compartment, generàlly desi~nated 312 in Figure 13, and a conduit laying compartment, generally designated 322 in Figure 13. The fill bin compartment 312 is for receiving fill material (shown at 3()8 in Figure 13) which is dispensed on the bottom of the trench and around the conduit 125 which is laid in the trench. A screen 314 covers fill bin 312 upper opening. The fill material must pass through screen 314 as it is poured into fill bin 312. The conduit laying compartment 322 provides a passageway for conduit 125, such as heavy cement, clay, or P.V.C. sewage pipe as shown in Figure 'q, to be passed through the boxlike structure 300 to the bottom of the t;ench. The conduit laying compa.tment 322 also contains the equipment necessary to properly align, set, and push the conduit out the 2~ ~`, r~4 !~ ?~
trailing end of ~he boxlikc structurc. As c~n be sccn in Figure 1~ thc fil3 bin comp~rtmcnt is dc.~ned by an interior transverse wall 390 and a porlion of Ihe rear wall 306. A chutc gcnerally designated 3fi8 in Figurc 14 is providcd bctwccn ~hc nll bin comp~rtment And the reAr exit 366 of îhe boxlike structurc 300.
The boxlike structure 300 further comprises a tow bar 346 and a tow loop 352 mounted on lhc forw8rd nose sec~ion 34n of ~hc boxlike struc~ure 300 as is shown bes~ in Figu* l3. The tow bar 346 is disposcd in hrackets 348 which are rigidly mounted on the forwsrd nose section 340 of ~he bnxlike structure 300. Thc tow bar 348 is used in the same manner as hereinbefore dsscribed The tow loop 3S2 is also provided to allow quick and easy grasping of ~hc tow loop 352 in order to draw the boxlike slructure through the trench which has been excava~ed. Tow loop 352 is preferahly a wire rope loop pivotally attached ~o eyelet s~uds 350 and also having a reinforcing sec~ion 334.
When the bucket of an excavating implemen~ (e.e. a backhoe) grasps the ~ow bar in ~he manner illus~ra~ed in Fi&ure I ~he opera~or can provide upward downward or side-to-side forces on ~he forward end wall while pulling ~he boxlikc structure throu~h the trench.
However due ~o the automatic shearing blade adjustment mechanism provided in the embodiment shown in Figures l3-14 it is not necessary that the implcment operator concern himself with careful manipulstion of the boxlike structure to keep in on-grade. Thus on many occasions ~he tow loop 352 may be used ~o draw ~he boxlike s~ruc~ure through the trench. Still the tow bar 346 may be used for making adjustments to the 8rade of the boxlike structure 300 and the implement opera~or has a choice of u~ilizing the tow loop 352 or ~he tow bar 346 for drawing the boxlike struc~ure 300 ~hrough ~he ~rench according ~o .. ~

2 ~ 2 he needs of the pnrticular circumstance3. The operation of the automatle shearing blade adjwtment mechanism will be explained in detail later.
The shearing blade 3S8, which includes ~ shearing edge 360, automaticRlly sdjusts up or down, as needed, as the boxlike structure 300 is drs~n through the trench. Thus, the bottom of the treneh 48 is au~omatically kept on-grade and the operator ~f the excavating implement may be less conc rned with appbing venical forces in order to keep Ihe boxlike s~ructure on-grade as is required with the previously described embodiments.
The structure indicated generally at 318 in Figures 13 and 14 comprises a motor which drives an electric generator and a hydraulic pump. The electric generaSor provides the electric power necessary to operate the laser leveling system used to control the aulomatic shearing blade adjustment mechanism and also provides electric power for the lights 392 in the conduit laying compartment 322 and various other functions requiring elec~ic power. The hydraulic pump provides hydraulic fluid under pressure required for the ~arious hydraulic rams tha~ are used in connection with the embodiment which wi11 be e~plained later.
The boxlike structure 300 further comprises features for securing the upper portion 302 tn the lower portion 304 in an aligned and flush engagement. This feature also permits the releasable attachment of the upper portion 302 to the lower portion 304. These features include engagement members ~00, receiving members 398, and latches 402 which operate in a similar manner to that previously described.
The embodiments shown in Figures 13-18 are uscd in a similar fashion to those embodiments shown in F~ures 1-12. As is shown best in Fi6ure l in connection with a 2 ~i ~,,?

previously described embodiment, thc cxcavating implement, such as a backhoe, digs a trench 48 in front of ~he boxlike structurc 300. Fi~ure 13 shows the boxlikc structure 300 in such a trencb 4~. The boxlike structure 300 is drawn forward through the trench 4~.
conduit 125 is passed through the conduit laying compartment 322 to the bottom of ~he trench 48. The conduit 125, if composed of individual lengths, are secured to~ether in the bottom of the boxlike structure 300 before bein~ pushed out the rear 336 of the boxlike struc~ure 300 onto the bottom of the trench 48. As the conduit 125 is fed out the rear end 366 of the hoxlike structure 300, ~he fill material 308 (not shown in Fi~ure 14) is dischar~ed from the fill material chute 368 and envelops the conduit nn all sides with fill material 30 as shown in Figure 13. Thus, the conduit has been laid in the hottom of the trench and 1S
ready for the trench to be back filled immediately, as is indicated in Figure 1.
As is the case with the em`oodiment shown in Figures 1-12, the embod;ment shown in Figures 13-14 allows the trenching and conduit laying operation to be performed continuously. The excavating implement continuously digs a trench 48 in fron~ of the b(~xlike structure 300. The boxlike structure 300 is then drawn forward by the backhoe into the newly dug trench. a front loader, for example, may also be used to supply the fill material hin 312 with gravel or some other fill ma~erial, and for back fillin~ the trench behind the boxliké structure 300 with the material which the hackhoe has removed. also, the backhoe may be used to lower the conduit 125 into the conduit laying chamber 322 and for removing the upper portion 302 of the boxlike structure 300 from the lower portion 304, if required.
As will be appreciated, similar to the embodiments previously described, the emhodirnent shown in Figures 13-14 provides that an underground contractor may lay 2~ 'J~

conduit in Icss ~han half the time required using previ. .lsly available structures and methods.
Furthermore, since excavating implements, k~, backhoes, are no~ sitting idle this expensive equipment is being used much more emciently. Thus, on any projec; fur laying subterranean conduit, these advantages can produce drastic savings in equipment rental costs and labor costS
The alltomatic on-~rade adjustment mechanism included in Ihe embodiment shc,wn in Figures 13-14 is particularly useful in increasin~ the cfficiency of a conduit laying operation. since the operator of the excavating implement is not required to give us strict a~tention to maintainin~ the boxlike structure 300 on-,~rade, the conduit laying operation may proceed at an even faster pace than when using the previously described embodiments.
Figure 15, which is a detailed cross-sectional view of the forward nose portion 340 of the boxlike structure 300, will be used to in explaining the functioning of the automatic on-grade adjustment system. As is the case in the embodiment shown in Figure 1, a laser transmitter (not shown in Figures 13-18) is provided above ground. The level of the beam transmitted hy the laser transmitted is set so as to be precisely the appropriate distance above the grade on which the bottom of the trench is to be sheared. In Figure 14, which is a cross-sectional view of the boxlike structure of the present embodiment, tne laser receiver 326 is shown mounted upon a vertically sliding mast 328. The mast is held against the internal side of wall 303 of the boxlike structure by guides 408 which allow the mast to move in a vertical direction, but not horizontally. The laser receiver 326 intercepts the laser beam and, in connection with the receiver control circuitry 320, determines if the laser receiver is above, below, or at the proper height. The internal mecllanism contained in the r ~ 2 ~ . ..--forward nose portion 340 which responds to thc rcceiver control circuilry 302 is shown in more detail in the cross-scction view of Figure 15.
In Figure 15, the mechanical and hydraulic structurc which is responsible for carrying out the sutomatic shearing blade adjustment can be seen. In Figure 15, some of the structures are shown when shearing edge 360A is in a lower most position. A shearing edge 360 is provided on shearing blade 358. The shearing edgs 360 of the shearing blade 358 is provided with a point for efficiently shearing off the earth at the proper level. The shearing blade 358 may be constructed of a single piece of rnaterial or, as shown in Figure 15, may be braced with a bracing member 362. The shearing blade is attached to the mounting plate 356 which is in turn attached to the backing plate 468 by bolts 478 and nuts. The nose sèction forward wall 364 is provided with a hole 476 through which the mounting plate 356 attaches to the backing plate 468. Thus, as the backing plate 468 is raised and lowered, mounting pa~e 356 is also raised and lowered which causes the shearing ed6e 360 to be raised and lowered also. Two positions of the components are shown in Figure 15 oy the solid image and the outline image. The boxlike structure bottom 344 along the nose portion is angled upward so as to not interfere with the operation of the shearing edge 358.
The backing plate 468 is connected to a pivoting arm 473. The pivoting arm 472 is pivoted about its approximate mid-point by a two point pivoting member 471. Position of the pivoting point may be altered from that shown in Figure 15 to provide additional ..
leverage or increased movement of shearing blade 358 as is needed. The structure of the pivotjng arm 472 and the two point pivoting member 471 can also be seen in the perspective view of Figure 14. As seen best in Figure 15, the two point pivoting member 471 is pivotally / f~ 3 ~ 2 , attached to the pivoting arm 472 by a bolt 473 and 81so pivotally attached to a mounting member 477 by bolt 475. A second end of the pivoting arm 472 is connected to the rod 466 of a hydraulic cylinder 462. As the rod 466 of the hydraulic cylinder 462 is extended or retracted, pivoting arm 472 is caused to move which in turn causes backing plate 468 and mounting plate 356 to move either up or down.
Since mounting plate 356 and backing plate 468 "sandwich" the front ~ all 364 of the nose section, mounting plate 356 is restricted from moving in other than a vertical direction.
In the embodiment shown in Figures 13-15 no particular friction reducing device is used between mounting plate 356, backing plate 468, and the front wall 364 of the nose se.:tion.
However, such a friction reducing material could be used with the presen~ invention. In the present embodiment it has been determined that constructing mounting plate 356, backing plate 468, and nose section front wall 364 of a material having sufficient strength so as to withstand the pressure created by the earth moving against the shearing blade 358, provides hat the friction between these sections is of little concern to the proper operation of the ~mbodiment. Still further, redJcing the friction between these structures is dimcult because ~f the infusion of dirt experienced during operation.
The two point pivoting member 471 is necessary, as opposed to a one point pivot, iince mounting plate 356 and backing plate 468 are allowed to travel only in a vertical plane.
rhe struCture shown in the cross-sectionai view of Figure 15 provides the essential functions ~f the ori-grade adjustment mechanism with a minimum of complicated equipment. The tlYdraulic cylinder 462 is pivotally mounted to the angled upper wall 342 of the nose portion ~y brackets 458 and 464 and bolt 460. ~s can be seen best in the perspe~f-;c view of Figure 2~ ~ D? ~ ~

14, pivot;ng arm 472 is a tubular-sbaped member b~ing formed in a U-shape, the distal ends ~f ~hc legs of the "U" hei:lg pivotally atta;,hed to the brackets 470 attached to backing plate ~68. The U-shape of the pivoting arm 472 can be seen best in the top view of Figure 16.
Also apparent from Figure 16 is that pivoting members 471 are connected to apprnximately the mid pcin.ts of each of the "legs" of the pivoting arm 472 by bolts 473. Thus, as the end of pivoting srm 472 which is connected to the hydraulic ram 462 is moved up and down, it sravels in a slight arc due to the fact shat backing plate 468 is allowed to move only in the vertical plane.
Whether hydraulic ram 462 extends of retracts is determined by whether the laser receiver 326, and its associated circuitry, determines that the shearing ed~e 360, and thus the bottom of the trench, is above, below, or on-grade. Thus, if the laser receiver 326 determines that the position of the shearing edge 360, and thus the bottom of the trench, was above-grade in the position shown in the sold image of Figure IS, the shearing blade 3djustment mechanism would cause a solenoid valve to open (not shown) which would cause ~ydraulic ram 462 to retract cylinder rod 466. This would cause pivoting arm 472 to move ~nd force backing plate 468 and mounting plate 3S6, and thus also the shearing blade 358, iownward in the position shown by the dotted image 358A of Figure 15.
The height at which the laser receiver 326 is held is determined by the position of the ~acking-plate 468. As can be seen best in Figure lS, a laser mast support rod 452 is ~onnected to backing plate 468. A reinforcing strut 454 is attached between backing plate md mast support rod 452 so as to provide diagonal support. Mast support rod 452 extends t an angle through the nose portion of the boxlike structure until it comes to a position ~t~ ~zr;~7~
. .J ~ .J

rectly below thc laser rcceiver mast 328. Both the top cnd of the mast support rod 452 nd the bottom end of thc laser receiver mast 328 are provided with horizontal nat end embers, 451 and 4S3, respectively. Mast support rod 452 is positioned such that as backin~
~late is moved vertically a particular distance, the laser receiver mast 468 is also moved the ;ame distance. Mast support rod 452 and laser mast 328 are not secure~ ether St) that when the upper portion of the boxlike structure is separated from the lower portion, no connections need be dismantled.
In operation, as the laser receiver determines that the shearin~ ed~e 3fi~) is above grade, the pivotine arm hydraulic ram 4fi2 is ahove ~rade, the pivotin~ arm hydraulic ram 462 is caused to retract which forces the shearin~ ed~e 3fiO downward while at the same time lascr receiver mast 328, and thus the laser receiver 326, is also moved downward the same distance. When the shearin6 ed~e 360, and thus the laser receiver 32fi, has been moved back on-~rade, the on-~rade condition will he sensed hy the laser receiver 326 and the action of hydraulic cylinder 462 will be discontinued. In this fashion, it is not necessary that the boxlike structure be moved up or down hy the implement operator to maintain the conduit on-~rade but the mechanism of the embodiment illustrated in Figure 13-15 maintains the bottom of trench 48 on-~rade.
The emhodiment shown in Fi~ure 14 is provided,with a pump 4]2 to remove water which-collects in the conduit layin~ compartment 322 portion of the hoxlike structure. The pump 41~ takes up water from the bottom of the boxlike structure and forces it intn a pipe 384 provided on both the lower and upper portion of the boxlike structure. The pipes on the lower and upper portions of the boxlike structure are interconnected by a releasable coupling 410 so as to facilitatc the separation of the two portions of the boxlikc structure.
Thc water which is discharged from the pipe 384 which exits from the upper portion 382 of the boxlike structure is carried away from the trench by way of a hose 380. As is the case with the previously described embodiments, the water removal function may be provided by many different systems other than that shown in Figure 14.
The embodiment shown in Figure 13-14 is particularly well-suited for laying conduits such as heavy cement, clay, or P.~'.C. sewage pipe. After the initial length of trerch has been excavated to the proper depth, and the boxlike structure placed on the bottom thereof, a length of conduit is loweled through the top of the boxlike struct~re into the conduit laying compartment 322. As shown in Figure 14, the forward vertical wall of the conduit laying compartment is provided with a cnnduit guiding ramp, 416 and 418. The conduit guiding ramp consists of a vertical portion 416 and a sloping portion 418.
To insert conduit into the iaying compartment 322, the conduit 125 is lifted from a flatbed truck, or some other supply of conduit, by an excavating implement at the trenching site. The length of conduit is held in a vertical position and placed against the vertical portion 416 of the conduit guiding ramp. As the length is slowly lowered, the first end Gf the conduit meets the diagonal portion 418 of the conduit guiding ramp. As the conduit 125 is continued to be lowered into the conduit laying compartment 222, it is guided onto the first set of conduit support rails 480A and 480B, one of which is shown in the perspective view of Figure 14 and both of which are shown in the top view of Figure 16. The conduit comes to rest in a substantially hori~ontal attitude on the conduit support rails 480A and 480B, as shown by the ghost images of the conduit ]25 illustrated in Figures 14 and 16.

2 ~

llle apparatus of the embodiment shown in Fi~ure 14 is panicularly well-suited for laying ind;vidual len~ths of conduit which havc a bell 125A, or a fla!cd portion, at one end.
In the embodiment shown in Figure 14, the exact grade on which the conduit will be laid i5 determined by the beight of the condnit support rails, 480A and 480B as well as 482A and 482B, rather than the depth of the trench. Thus, a structure is provided for raising and lowering the levels of the conduit support rails 480 and 482.
In the present embodiment, the height of the conduit support rails 480 and 482 may be adjusted by screw mechanisms ~enerally designated by the structures marked 484 492.
Each section of pipe suppon rails is provided with two height adjustment screws, making a total of eight shown in Figure 16.
The structure of the height adjustment ~crews 484 492 can be seen in detail in Figure 17. A threaded bracket 492 is attached to the side wall 303 of the boxlike structure through which the screw 494 is placed in threaded engagement. A handle 496 is secured to the end of the screw 494 so as to facilitate rotation of the screw 494 by a workman stationed within the conduit laying compartment 322. The other end of the screw is provided with an opening through which a flat headed button 508 is placed. Thus, the button 5()8 moves vertically as the screw 494 is rotated without hindering the screw's rotation. The shaft portion of the button 508 protrudes from the center of the screw 494. The shaft portion of button 508 is attached to rail suspension bracket 502 by connector 510.
The pipe support rail 480A is provided with a length of U-channel member S00, shovn in Figure 17, commonly called unistrut in the art, upon which the rail suspension bracket 502 is attached. The use of the unistrut channel member 500 and a nut and bolt 506 2 ~

to attach the r;-.. suspension bracket 5()2 to the condui~ support rail 480A ailow~ ~h-. conduit support rail 4XOA to be moved horizontally such thal differcnt diameters of umduit muy he accnmmodated. The bracke~ 502 has a tlat ~uide memher 504 which is inserted throul h a bracket 498 protrudin~ from the side wall of the boxlike structure. Thus, by the structure described, the conduit support rails may be positioned both vertically an(J horizont.-lly. It should be appreciated that many different structures could be used to provide the positionin~ of conduit uuide rails 4X() and 4X2.
With an initial len~th of a)ndui~ bein~ horizontally ph~ced on the first paid of conduit pipe support ruils 48()A and 4808, and the bottom of the trench bein~ sheared at the proper ~rade, the conth.uous chain drive shown in Fi~ure IX is activated by u workman sUpervicinu the operation. For the convenience of the workrnan, a remote control for directin~ the operation Of the mechanisms descrioed herein, shown in Fiuure 13 Dt 33(), is connected to the control mechanisms of the apparatus by u cahle 332. As a len~th of conduit reaches a horizontal pnsition it strikes condui~ sensin~ switch actuator 542. Conduit sensin~ switch 54() detects when the conduit has reached the horizontal position on the first pair of conduit support rails 48t,A and 4P,()B. When the continuous chain 530 is activateu, one of two chain drive fin~ers 536A or 53fiB meets Ihe end of the con(luit 125. The chain drive 53() exerts pressure on the end of the conduit thus pushinl! the len~th ol conduit 125 out the trailin~
er~d of the boxlike structure. Thus, the lenl!th of conduit is m~wed from the first pair of a~nduit support raiis 4X()A auc' tX()B to the second set of conduit support rail.c 4X2A and 4X2B.
As mentioned previously, the embodiment shown in FiL~ures ~h-lX is pilrticulilrly well-2 ~

suited for laying conduit which has a bell at one end thereof. As shown in Figwe 14, Ihc second pair of conduit support rails 482 may be vertieally adjusted so as to be lower than the first pair of conduil support rails 480. Thus, as the initial len~th of conduit is pushed onto the second pair of conduit support rails 482 the height of the conduit is such that a second length of conduit being placed on the first pair of conduit support rnils 480A und 4BOB is readily slid into sealing enga~ement with the bell of ~he initial length of conduit 125.
In most cases, the length of the conduit will be such that it will only be parti tlly supported by the second pair of conduit support rails 482 and the conduit will be partially lay.ng in the trench.
The second length of conduit is pushed into sealing en8agement with the bell of Ihe initial length of conduit by a conduit seiting mechanism shown in Figure 18. The settings mechanism includes a hydraulic ram 552. Hydraulic ram 55" is attached to conduit suppo,t rail 480A by mounting bracket 554. The hydraulic ram rod 556 is connected to an interconnecting bracket 55S whieh is adjustably positioned within a len~th of unistrut s6n.
(The adjustin~ strueture is not shown in the figure.) Also, a push arm 562, whieh is the strueture that makes eontaet with the end of the eonduit, is also positioned within the length of unistrut 560. The conduit setting hydraulie ram 552 used to push the lengths of conduit into sealing en~agement is provided with a short stroke since the positioning of the push arm 562 relative to hydraulic ram rod 556 is adjustable. Thus, when conduit is in place on support rails 480A and 480B the conduit need only be pushed a short distance to sel the ..
ends of the conduit in sealing enga8ement.

Once conduit setting hydraulie ram 552 provides that the lengths of conduit are 2 ~ 7 2 placed in sealing cnga~ement with each other, a task which sometimes requires a considerable amount of pressure which can be provided by a hydraulic cylinder, Gne of the continuous drive chain fin~ers, 536A or 536B, is causcd to abut the end of the second length of conduit and push both lengths of conduit out of the trailing end of the boxlike structure as the boxlike structure is drawn forward through the trench.
Continuous chain drive 530 is driven by a hydraulic motor 512. A hydraulic motor is used so that constant pressure may be maintained on the conduit even while the conduit is not moving. The mo!or Sl is driven by hydraulic fluid communicated through hydraulic lines S14. The hydraulic pump is located with the other control mechanisms indicated at 318 in Figures 13 and 14. The hydraulic motor l~ase 516 is a;tached to mounting plate 518 which slides horizontally. The continuous chain S30 is coupled to the motor by a sprocket (not shown in Figure 18 but indicated at 528A). The horizontal position of hydraulic motor 512 is adjusted by the position of adjusting bolts 524 which are threaded into adjusting bolt bracket 552 which is attached to support rail 4808. Adjusting bolts 524 abut the edge of mounting plate 518 to assist the horizontal positioning of mounting plate 518. Mounting plate can be secured in position by bolts 520 which are threadably attached to support rail 480B. The tension placed on continuous chain 530 may be adjusted by varying the position of motor mounting plate 512. Chain drive 530 is disposed within chain drive channel 534 provided on suppon rail 480B. Chain drive channel 534 is provided with a liner 532 to .. ~.
smooth the travel of chain drive 530. It will be appreciated that while the above-described structure facilitates the efficient laying of conduit, struclures other than those hereir, described may also be used.

~Q~ 372 Additionally, thc pressurc exerted by continuous chain drive fingers 536A or 536E~
provide that the lengths of conduit will be main~ained in sealing engagement while the conduit is moved out the trailing end of the boxlike structure 366. Once the sccond length of conduit has been moved off of the f~rst pair of conduit suppon rails 480A and 480B onto the second pair of conduit support rails 482A and 482B, the chain drive finger, S36A or 536B, slips off the end of the second length of conduit as the chain drive travels around the sprocket located at the trailing end of the conduit support rail 480B. Fingers 536A and 536B are attached to just one chain link, only one attachment is indicated at 538, so as to facilitate the smooth motion of continuous chain 530 around sprockets 528A and 528B.
After the boxlike structure has been advanced in the trench to the point where the second length of conduit has just been removed from the first pair of condui~ support ~ails 480 the backhoe operator no longer draws the boxlike structure through the trench, but proceeds to have another l~ngth of conduit 125 lowered into the conduit laying chamber 322.
The next length of conduit (not shown) may be lowered into conduit laying chamber 322 in a nearly vertical orientation with the lowermost end of the next length of conduit being placed in position to contact the bell end 125A of the conduit resting on the first pair of conduit support rails 480 and the bell end of the next length of conduit leaning against the vertical conduit guiding ramp 416. Thus, when the boxlike structure is again moved through the.trench, the next length of conduit is slowly moved from a vertical orientation to a horizontal orientation onto the first pair of conduit support rails 480. In this manner, the lengths of condui~ may be set without the need for a workman to be stationed within the conduit laying compartment. By repeating the above listed steps, a very emcient conduit laying operation may bc carried out.
As explained in connection wi~h ~he previously described embodiments, the boxlike structure 300 may be separated into an upper portion 302 and a lower portion 30~ when an underground obstacle, primarily utility lines, is encountered. When such an obstacle is encountered, the upper portion is released from the lower portion by disenga~ing the latches 402 from the brackets 404 shown in Figure 14. Also, fill material chute gate 370 i5 closed by means of the hydraulic ram 376. Thus, when the upper portion is lifted off fr~m ~he lower portion using cables attached to lifting ears 324, in a manner similar to that shown in FiSure 4, a minimum amount of fill material is spilled into the trench. Furthermore, the present embodiment may be used to lay flexible conduit by incorporating structures similar to those previously described.
Also, when the upper portion is removed from the lower portion, structures may be provided (but are not shown in the figures) to allow the laser receiver mast 328 to he mounted to the mast push rod 452, shown in Figure 15, at the proper height. In this way, the laser receiver system may be used to maintain the bottom of the trench on-grade up until the time that laser mast 328 must be removed in order to clear an underground obstacle. Furthermore, similar to the previously described embodiments, the embodiment illustrated in Figure 14 is provided with transverse rods 394 to provide support for the side walls 303 of the boxlike structure. Also, the upper portion is always placed in proper alignment with the lower portion because of nesting protrusions 400 are received by nesting cups 398 in a nesting engagement.
As can be seen from the cross-sectional view of Figure 14, fill material chute 368 . ,: 2 ~ 9 ~' dischargcs fill matcrial at the trailin~ cnd 366 of thc boxlikc structure. The floor 345 of thc boxlikc structure, and thc second pair of pipe support rails 482A and 482B, terminated priol to the place wherc fill material chute 308 discharges its contents. As thc conduit 125 is pushed out she trailing end of the boxlike structure a volume of fill material envelops the cond-~it 1~5, both under and around the conduit. This occurs because the end of the conduit which has left the boxlike structure is supported on one end off the bottom of the trench by suppon rails 482A and 482B and thus there is a gap between the bottom of the trench and the lower portion of the circumference of the conduit. Thus, as fill material is discharged onto the top of tht circumference of the conduit, it falls to the bottom of the trench under the conduit and also encompasses the conduit. Once a particular portion of conduit has been enveloped with fill material in this manner, the flow of fill material is self terminating since the fill material placed around the conduit "plugs" the fill material chute. However, as the boxlike structurc is drawn into the newly excavared trench, more fill material is discharged from the fill chute to continue the process.
Tlhus, using thc embodiments described in Figures 1-18, a subterranean conduit laying operation may be carried on much more efficiently than with any system hitherto known in the prior art. Particularly, the automatic Brade adjustment system provided in the embodiment shown in Figure 13-14 provides a particularly accurate and efficient conduit laying system.
An important feature of the present invention is the provision of alignment means for detecting if the conduit is being laid in alignment with a desired predetermined direction and pro iding an indication of alignment or misalignment so that any deviations can be ~1 immediascly corrected. Howe~er, unlike in the prior art, detection in accordancc with the imention is substantially at thc level or at thc point wherc thc conduit i5 being laid. For this purpos~, there is provided a laser transmitter arrangcd to pr~vidc a substantially horizontal alignment laser beam 64 arrsngcd in a vertica! plane which extends through the path along which the conduit is to be laid. The laser used for this purpose may be the same or different from the one used for maintaining the grade of thc boxlike structure 12.
Preferably, however, the same laser 58 is used as suggested, for example, in Figure 1, to provide both laser beams.
Reflecting means is provided on the boxlike structure 12 for intercepting and reflecting the alignment laser beam 64 used for maintain;ng the reflecting element within the vertical plane which extends through the conduit, the reflected alignment beam bein5 directed in a substantially vertical direction downwardly towards the conduit 125. Such refiecting means includes thc mirrors 602 shown in Fi~ures 1-3, 12-14. As will be more fully described below, indicating means is provided within the vertical plane substantially at the level of and proximate to the conduit 125 for intercepting the alignment laser beam and providing an indication of alignment or misalignment of the laser beam from the desired or predetermined path as a function of the deviation of the retlected laser beam from a predetermined reference point on the indicating means. The aforementioned feature for accurately moni~oring the alignment of the conduit with a desired directional path will now be more fully described in relation to Figures 19-25.
Referring first to Figures 19-20, a first embodiment of a mirror arrangement for reflecting the alignment laser beam 64 is generally designated by the reference number 600.

3 ~

A mirror 602 (not shown) is mounted on a support bracket ~04 to maintain thc mirror in a plane normal or perpendicular to thc vertical planc and inclined at an angle of 45 in relation to both thc incidcnt as well as thc reflected alignment laser beam, as will be more fully described below.
The bracket 604 forms part of or is mounted on a downwardly depending pendulum 605, the pendulum being pivotally mounted on a pivot pin or shaft 606 which is substantially in a horizontal planc and parallel to the alignment laser beam 64. A weight 608 is provided at thc bottom of thc pendulum 605 to maintain the pendulum in a generally upright orientation as shown in Figure 20. A mast 650, carried by thc pendulum 605, supports the mirror fiO2 at a height above the boxlike structure 12 to clear any obstacles and be in the line of the alignment laser beam 64.
~ eferring to Figure 20, a bushing 610 is mounted on the pivot pin or shaft 606. The bushing 610 is maintained between spaced downwardly depending arms 604a and 604b of the bracket 604. A spacer 612 is provided to substantially center the bushing 610 between ~e members 604a and 604b. Washers, 614, 616 such as fiber washers are provided on each side of the bushing 610 and a compression spring 618 is placed on the shaft 606 between a steel pressure washer 620, proximate to the arm 604b and ~he fiber washer 616. Brake adjustment screws 622 arc provided which can force the pressure washer 620 inwardly thereby compressing the spring 618. These aforementioned elements act as a break or damper on the pendulum 605 to prevent free rotation about the shaft 606 and maintaining the mirror 602 generally stable notwithstanding movements of the boxlike structure.
However, the arrangement described does allow the pendulum 605 to upright itself when the 2 ~

boxlike structurc 12 tilss from one side or to the other so that thc mirror 602 is always oriented in the same plane snd this assures that thc substantially horizontal alignmen~ laser beam 64 is always reflected into a substantially vertical beam independently of the tilt of the boxlike structure.
It will be appreciated that while the width of the mirror 602 is comparable to or less than the anticipated shifts in the mirror due to tilting of the boxlike structure 12, excessive tilt may prevent interception of the alignment laser beam 64 by the mirror. For this reason, there is illustrated in Figure 19 an arrangement for maintaining the position of the mirror 602 in the path or line of the incident alignment laser beam 64. For this purpose, there is provided a slide 630 which, by means of a bearing 632, is linearly moveable along a rod 634 the width of which should be at least equal to the anticipated lateral shifts of the mirror 602 as a result of tilt by the boxl ke structure 12. The rod 634 is fixed to the boxlike structure 12 in any conventional way, such as at 636. A ball screw and nut arrangement 639 is provided spaced from the rod 634 and a ball nut 640 is threadedly mounted on a screw drive 642 which is also fKed to the boxlike structure 12, as at 644. The screw drive 642 is substantially parallel to the rod 634 and is provided at one end thereof with a reversible gear motor 645 which can rotate the screw drive 642. The motor 645, can, therefore, rotate the screw drive 642 in one direction or another thereby moving the ball nut 640 to the right or to the left, as viewed in Figure 19. Suitable coupling means is provided for coupling the ball nut 640 to the pendulum 605. While conventinnal coupling can be used, a pair of suitably ears or lugs 646 on the ball nut 640 is shown capturing a follower 648 on the pendulum 605.
In this manner, lateral movements of the ball nut 640 carries with it :he pendulum 60' and, 3t~ 2 thcrefore, the mirrsr 602. Thc motor 645 can be actuated in any appropriate manner which is responsive to lhe degrec of tilt or excessive latcral shifts of the boxlike structure. This may takc the form of a separate sensor or may be controlled by a signal derived from the circuitry which monitors thc Brade and/or the alignment of ~he boxlikc structurc. Another possibility is the use of a potentiometer or other sensing device which cooperates with the tilt indicator 182 used to provide the degrce of tilt of the boxlike structure 12.
Referring to Fi~ure 21, thc laser receiver 60 is shown mounted, as well, on Ihe pendulum oO5 by means of thc mast 650, on which the mirror 602 is also mounted. The mirror 602 intercepts the alignment laser beam 64 and reflects or diverts it from ;J
substantially horizontal direction to a vertical direction by deflecting it 90-. The resulting vertjcal beam 6~' is directed, therefore, into the boxlike structure 12 consisting of the upper and lower portions 20, 22 respectively. The downwardly directed beam 64' is, therefore, directed toward the conduit being laid; It will be appreciated that the laser beam portions 64 and 64' define a substantially vertical plsne which extends through the path or direction in which the conduit is to be laid. In the embodiment of Figure 21, a separate drive screw arrangement 639 is omitted and a larger drive screw 642 and ball unit is used which directly supports the pendulum 605. Here, the c~sntrol signal to rotate the screw drive motor 64S
can be derived from a sensor 60' which can detect when the received alignment beam 64 is shifted from center relative to the sensor 60'. The pendulum is thereupon shifted to again center the beam 64 on the sensor 6O'. Any conventional feedback circuit can be ued for this purpose. The operation of the drive is otherwise similar to that shown in FiQures 19-20.
In the region just above or proximate to the conduit a target 6S4 is shown in Figure 3 . 2 21 which may be appropriately marked reflecting tapc. The beam 64' prime will s~nerate an opt;cal image on the targ~t 654 and this can be observed visunlly by an opera~or.
However, the target 654 can also cumprisc a receiver which can electronically monitor the reflected beam 64' prime and ~ener~e a suitable control siEnal for operating the side to side movements of the track. A cradle 656 supporting the targe: 654 by means of a rod 65~3, spans around the conduit in the tracks. The movements and positions of the target 654 are, therefore, directiy related to the positions of the sracks and the condt;,~ being laid. To mnke adjustments, the operator causes the bucket of the excavating implement to ap?ly upward, downward or lateral force at the tow bar or track to compensate for any disaiignment or to correct for the distance off-grade.
As shown in Figure 21, the pendulum 60j is moun~ed between the side walls of the boxlike unit and below the upper edges thereof. In order to intercept the alignment laser beams which are transmitted above the structure, a mast 650 is supported on the pendulum 605 and projects upwardly above the level of the boxlike unit to a point where the laser beam is projected.
Referring to Figures 22 and 23, an alternate embodiment 600' ofthe mirror supporting structure is illustrated. In the embodiment of Figures 20-21, the mirror 602 is relatively narrow in width. The purpose of providing the traverse ball screw mechanism 639 was to move the mirror into line with the alignment laser beam 64 during conditions of excessive tilt or lateral shifts. It is anticipated that the boxlike structures 12, which is typically 36 inches wide, will shift approximately plus or minus five inches maximum at the top of ~he unit. Accordingly, if a mirror 602 is providod with a width of 6-~2 inches it should be 2 ~ ~b 7 ~

adcquate ~o capture the laser beam 64 within the anticipatcd tilt or shift range. In this embodiment"hereforc, only a pivot 606 is provided, without a traverse mechanism. The counter weight 608 still maintains thc mast 650 in a substantial vertical direction ar.d, thcreforc, the mirror 602' remains in a substantialiy horizontal orientation. t~low, with o lateral shift or tilt of thc boxlike struc~urc 12, thc mirror 602' will continue to prnject or reflect the alignment laser beam 64 in a vertical direction as aforementioned.
Figure 24 shows the details of the arrangement shown in Figures 22-Z3, where only a pendulum 605 is provided for righting the mast 650 so that the mirror 602' prime will always be properly oriented. As with the initial embodimer.t shown in Figures 19-21a, suitable damping mechanism may be used to avoid excessive free swinging or rotation of the pendulum.
In Figure 25, there is illustrated three positions of tilt of the upright boxlike structure 12, illustrating for each position an associated position of the pendulum 60S and the mirror 602' mounted thereon. As w ill be noted, therefore, for each tilt position, the mirror will continue to be in a horizontal position.
While the laser beams 64 and the sensors in Figures 19-25 are all used for measureing and monitoring of alignment, separatc lascr beams and scnsors being used for grade, as suggested in Figure 1, it is possiblc to utilize a single laser to achievc both ends. For this purposc, thcre are available lasers which provide simultaneous plumb and rotating beams which utilize a prism assembly to providc two beams which are at a constant 90- alignment relative to each other. Such a laser is manufactured by Spectra-Physics of Dayton, Ohio, and sold under Model Numbers 910 and 942. With such a laser, the present invention can also 2~ " ~3 . 2 he used. In this case, the sensor 60 for gradc can bc mounted ~o one side of ~he boxlike Structure 12, as suggested in Figurc 2. The horizontal part of thc laser bearn is sufflcicntly wide so as to intercept the sensor 60. However, the vcrtical part of the laser beam is projected on line and, therefore, down the middle of the hoxlike structure. In this case, therefore, the line mirror 602 as well as the associated sensors are all arran6e~1 suhstanti;llly in the middle or the center of the boxlike structure Ih The vertical part of the laser he;lm is, therefore, projected as aforementioned downwardly into the boxlike structure to impin~e upon 2 target or suitable sensor as suggested. It will he ohvious, therefore, that numerous arrangements may bc utilized while still practicin6 the pres i /ention, the only requirement being that an aliSnment laser beam or laser beam portion is projected substantially vertical by downwardly at the conduit along the line in which the conduit is to be laid. Other approaches for achieving this result may be used if the same results are achieved.
The present invention may be embodied in other specific forms without departin~
from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (39)

1. An apparatus for laying conduit within a trench comprising:
a boxlike structure having end walls and side walls;
a conduit laying compartment disposed within said boxlike structure, said conduit laying compartment comprising means for receiving said conduit and means for lowering said conduit to the bottom of said boxlike structure and for discharging said conduit onto the bottom of said trench;
drawing means connected to the leading end of said boxlike structure for grasping and advancing said boxlike structure along the bottom of said trench;
grade detection means for detecting when the bottom of the trench is at the desired grade and for generating a signal indication when the bottom of the trench is offgrade;
alignment means for detecting, substantially at the level of the conduit being laid, if the conduit is being laid in alignment with a desired predetermined direction and providing an indication of alignment or misalignment; and adjustable blade means, positioned at a leading end of said boxlike structure, for grading and maintaining the bottom of the trench at a desired grade as said boxlike structure is drawn through the trench, said blade means comprising positioning means, connected to said grade detection means, for automatically adjusting said blade means in response to the signal generated by said grade detection means such that when the bottom of the trench is detected as being off grade said positioning means will automatically reposition said adjustable blade means independent of said drawing means so as to achieve the desired grade as said boxlike structure is moved through the trench.

2. An apparatus as set forth in claim 1 wherein said boxlike structure comprises separable upper and lower portions and securing means for securing said upper portion of said boxlike structure to the lower portion, said securing means comprising means for selective disengagement such that said upper portion may be disengaged and removed from said lower portion when a pipe or other obstruction is encountered in said trench through which said boxlike structure is being pulled, whereby the lower portion of said boxlike structure can be pulled under said obstruction by removing said upper portion.

3. An apparatus as set forth in claim 2 wherein said drawing means comprises a tow bar rigidly mounted on the leading end of the lower portion of said boxlike structure, said two bar being supported by brackets so as to receive in grasping engagement the teeth of a bucket of an operator-controlled back hoe.

4. An apparatus as set forth in claim 2 wherein said drawing means comprises a wire rope loop mounted on the leading end of the lower portion of said boxlike structure.

5. An apparatus as set forth in claim 2 wherein said securing means further comprises mating means for mating the upper portion of said boxlike structure in alignment to the lower portion so that the upper portion rests squarely on the lower portion.

6. An apparatus as set forth in claim 2 wherein said securing means comprises a plurality of engagement members extending below the lower edge of the upper portion of said boxlike structure, and a plurality of corresponding receiving members disposed on the lower portion of the boxlike structure for receiving in nesting engagement said engagement members.

7. An apparatus as set forth in claim 6 wherein each of said engagement members comprises a transverse rod extending between the side walls of said boxlike structure thereby providing support for the side walls.

8. An apparatus as set forth in claim 7 wherein each of said engagement members further comprise U-shaped brackets disposed at each end of said transverse rod and connected to the upper portion of said boxlike structure, and said receiving members comprise U-shaped cups for receiving in nesting engagement said U-shaped brackets.

9. An apparatus as set forth in claim 2 wherein said means for selective disengagement comprises a latch assembly for releasably coupling said upper and lower portions of said boxlike structure together.

10. An apparatus as set forth in claim 2 wherein said boxlike structure further comprises a bin formed therein for receiving and holding fill material.

11. An apparatus as set forth in claim 10 further comprising a chute leading from said bin to the trailing end of the lower portion of said boxlike structure, said chute conveying said fill material from said bin to the bottom of the trench so as to automatically encompass said conduit with fill material as it is laid.

12. An apparatus as set forth in claim 10 further comprising a gate disposed within said upper portion of said boxlike structure and means for shutting said gate so as to close said bin when the upper portion of said boxlike structure is removed from the lower portion, thereby preventing spillage of said fill material.

13. An apparatus as set forth in claim 1 wherein said adjustable blade means comprises an adjustable shearing blade and wherein the apparatus further comprises means for restricting the movement of said adjustable shearing blade to a substantially vertical plane.

14. An apparatus as set forth in claim 1 wherein said grade detection means comprises:
a laser transmitter disposed to provide a laser signal at a predetermined level above the desired grade; and a laser receiver mounted on said boxlike structure for sensing the laser signal from the laser transmitter and for determining whether the depth of the trench is above or below the desired grade.

15. An apparatus as set forth in claim 14 wherein said laser transmitter comprises means for providing an alignment beam and said boxlike structure further comprises a target mounted proximate to the conduit which provides a visual display of the alignment beam whereby the operator of the apparatus can visually determine if the conduit being laid is in alignment and on grade.

16. An apparatus as set forth in claim 1 further comprising a dewatering system disposed within said boxlike structure, said dewatering system comprising suction means for discharging water that collects in said boxlike structure from said trench through an exhaust conduit to a location outside of said trench.

17. An apparatus as set forth in claim 1 wherein said boxlike structure has longitudinal bracing members on the side walls for improving the rigidity of the boxlike structure.

18. An apparatus as set forth in claim 1 further comprising a vertical tilt indicator means for displaying whether said boxlike structure is vertically off-center.

19. An apparatus as set forth in claim 1 further comprising a conduit setting means positioned within said conduit laying compartment and comprising means for engaging individual lengths of conduit to each other and for placing said conduit on-grade within the trench.

20. An apparatus as set forth in claim 19 wherein said conduit setting means comprises:
a first conduit support means for substantially horizontally supporting a first length of conduit;
a second conduit support means for substantially horizontally supporting a second length of conduit; and ram means for effecting engagement between said first and second lengths of conduit.

21. An apparatus as set forth in claim 20 wherein said conduit setting means further comprises ramp means for guiding each said length of conduit, in turn, from an upper opening formed in said conduit laying compartment to a lower portion of said conduit laying compartment.

22. An apparatus as set forth in claim 20 wherein said first and second conduit support means are independently adjustable such that the first length of conduit may be supported at a height which is different than the height at which the second length of conduit is supported.

23. An apparatus as set forth in claim 22 wherein said first conduit support means is positioned at a height which allows an end of the second length of conduit to receive an adjacent end of the first length of conduit in axial alignment.

24. An apparatus as set forth in claim 20 wherein said conduit setting means further comprises a continuous chain drive which holds said first and said second lengths of conduit in engagement with each other while said continuous chain drive moves said lengths of conduit through a rear opening in said boxlike structure as said boxlike structure is pulled forward.

25. An apparatus as set forth in claim 24 wherein said conduit setting means further comprises a first sensor to detect when said first length of conduit is substantially horizontal and supported by said first conduit support means along its length.

26. An apparatus as set forth in claim 1 wherein said alignment means comprises a laser transmitter disposed to provide a substantially horizontal alignment laser beam arranged in a vertical plane extending through the path along which the conduit is to be laid;
reflecting means on said boxlike structure for intercepting and reflecting said alignment laser beam within said vertical plane to a substantially vertical direction toward the conduit being laid; and indicating means within said vertical plane proximate to the conduit for intercepting said alignment laser beam and providing an indication of alignment or misalignment of said laser beam from said path as a function of the deviation of said reflected alignment laser beam from a predetermined reference point on said indicating means.

27. An apparatus as set forth in claim 26 wherein said reflecting means comprises a mirror oriented in a plane normal to said vertical plane and inclined 45° relative to said alignment laser beam both before and after reflection.

28. An apparatus as set forth in claim 27 further comprising weighted pendulum means on which said mirror is mounted for maintaining the orientation of said mirror independently of tilt of said boxlike structure thereby assuring that said reflected alignment laser beam remains vertical regardless of the degree of tilt.

29. An apparatus as set forth in claim 28 wherein said mirror has a width less than the width of said boxlike structure and selected to insure that said mirror will intercept said laser beam in all anticipated tilt positions of said boxlike structure.

30. An apparatus as set forth in claim 29 wherein said mirror has a width within the range of 6-12 inches.

31. An apparatus as set forth in claim 27 wherein carriage means is provided which supports said mirror for moving said mirror in the direction of said vertical plane to compensate for movements of said mirror away from said vertical plane as a result of tilting movements of said boxlike structure.

32. An apparatus as set forth in claim 26 wherein said indicating means comprise a target which provides a visual indication.

33. An apparatus as set forth in claim 26 wherein said indicating means comprises a sensor which generates an output control signal which is used to adjust the position of a conduit laying apparatus inside said boxlike device relative to said path to bring the conduit into alignment with said path.

34. An apparatus for laying conduit within a trench comprising:
a boxlike structure having end walls, side walls, and a leading end;
drawing means connected to the leading end of said boxlike structure for grasping by an excavating implement and facilitating the advancing of said boxlike structure along bottom of the trench;
grade detection means for detecting when the bottom of the trench is at the desired grade and for generating a signal indicating when the bottom of the trench is off-grade;
alignment means for detecting, substantially at the level of the conduit being laid, if the conduit is being laid in alignment with a desired predetermined direction and providing an indication of alignment or misalignment; and an adjustable shearing blade positioned at the leading end of said boxlike structure, and comprising positioning means for automatically responding to the signal generated by said grade detection means and for vertically adjusting the position of said shearing blade independent of said drawing means such that when the bottom of the trench is detected as being off-grade, said positioning means automatically repositions said shearing blade so as to adjust the level at which the bottom of the trench is sheared to be on-grade.

35. An apparatus as set forth in claim 34 wherein said boxlike structure further comprises a conduit laying compartment comprising means for receiving said conduit and means for placing said conduit at the bottom of the trench.

36. An apparatus as set forth in claim 34 wherein said boxlike structure comprises separable upper and lower portions and securing means for securing said upper portion of said boxlike structure to the lower portion, said securing means comprising means for selective disengagement such that said upper portion may be disengaged and removed from said lower portion when a pipe or other obstruction is encountered in said trench through which said boxlike structure is being pulled, whereby the lower portion of said boxlike structure can be pulled under said obstruction by removing said upper portion.

37. An apparatus as set forth in claim 34 wherein said grade detection means comprises:
a laser transmitter disposed to provide a laser signal at a predetermined level above the desired grade; and a laser receiver mounted on said boxlike structure for sensing the laser signal from the laser transmitter and for determining whether the depth of the trench is above or below the desired grade.

38. An apparatus as set forth in claim 34 wherein said boxlike structure further comprises a bin formed therein for receiving and holding fill material.

39. An apparatus as set forth in claim 38 further comprising a chute leading from said bin to the trailing end of said boxlike structure, said chute conveying said fill material from said bin to the bottom of the trench so as to automatically envelope said conduit with so as to maintain the bottom of the trench on-grade.
87. A method is set forth in claim 83 wherein said step of maintaining said alignment of the conduit comprises the steps of providing a substantially horizontal alignment laser beam arranged in a vertical plane extending through the path along which the conduit is to be laid; intercepting and reflecting said alignment laser beam within said vertical plane in a substantially vertical direction toward the conduit being laid; and providing an indication of alignment or misalignment of said alignment laser beam from said path as a function of the deviation of said reflected alignment laser beam from a predetermined reference point within said plane proximate to the conduit.
88. An apparatus as set forth in claim 87 wherein said step of intercepting and reflecting includes maintaining said reflecting beam in a substantially vertical direction by adjusting the orientation of a reflecting mirror to compensate for tilt of said boxlike structure.
89. An apparatus as set forth in claim 87 further comprising the step of monitoring the position of said reflected alignment laser beam relative to the conduit; and adjusting the movements of said boxlike structure as a function of the indications of said beam positions.