US2746516A

US2746516A - Pipe line installation equipment

Info

Publication number: US2746516A
Application number: US505462A
Authority: US
Inventors: James D Cummings
Original assignee: AUBREY S CRUTCHER
Current assignee: AUBREY S CRUTCHER
Priority date: 1955-05-02
Filing date: 1955-05-02
Publication date: 1956-05-22
Anticipated expiration: 1973-05-22

Description

y 2, 1956 J. D. CUMMINGS 2,746,516

PIPE LINE INSTALLATION EQUIPMENT Filed May 2, 1955 4 Sheets-Sheet 1 a v l a 2 #Q m L,

Q C X R by w {q e Q m James fl Comm/0y; g INVENTOR.

ATTORNEY May 22, 1956 J. D. CUMMINGS PIPE LINE INSTALLATION EQUIPMENT 4 Sheets-Sheet 2 Filed May 2, 1955 dam e: 2. Cum/rung;

INVENTOR.

1 C Nam-u,

ATTORNEY May 22, 1956 Filed May 2, 1955 J. D. CUMMINGS PIPE LINE INSTALLATION EQUIPMENT 4 Sheets-Sheet 3 (/00? e; fl. Cum/77mg;

INVENTOR.

y 22, 1956 J. D. CUMMINGS PIPE LINE INSTALLATION EQUIPMENT 4 Sheets-Sheet 4 Filed- May 2, 1955 dame: 1?. 6007/77/07;

INVENTOR.

Q Mzlw' United States Patent PIPE LINE INSTALLATION EQUIPMENT James'D. Cummings, Houston, Tex., assignor of one-half to Aubrey S; Crutcher, Houston, Tex.

' Application May 2, 1955, Serial No. 505,462

17 Claims. (Cl. 154-41) of the'abutting load transfer surfaces, one on the other,

during the relative cradle and pipe travel.

In the installation of a pipe line, the commonpractice is to joint pipe sections end to end on the ground beside aprecut trench-and then employ tractor suspended cradles which, as the tractors move forward, lift the pipe for final, work performing operations to condition the pipe for subsequent burial. The conditioning may include the customary cleaning, priming, coating, and wrapping operations; and after. their performance, the pipe-with its 2,746,516 Patented May 22, 1 956 ice to be {raised and supported by a series of cradles in tandem spacedrelation for work performing-operations on'the elevated pipe, including the priming of the pipe surface witha thin film of paint, followed by the applicationthereto. of a thicker protective coating in a hot fluid condition, with any load bearing through the primer film andthe coating being such as to reduce objectionable surfaceinjury or appreciable pressure displacement of either:

' The improved cradles are readily adapted for stationary installation with traveling pipe, but they will also find great utility for traveling work on stationarypipe to condition it'for immediate deposit in a trench. Traveling equipment is here selected for illustration ofa specific embodiment of the. invention, and inthat usage-teachcradie is suspended from a side boom of a traction vehicle traveling forward on the ground. atone side :of thepreformed trench; To supplement side boom draft on' the cradle as supplied by the ground traction vehicle, it will be'helpful in many cases to apply power for directdrive of the endless sling carrier for cradle traction on the supported pipe. at a rate synchronized with traction vehicle speed. This will be advantageous when operatingon hilly ment wherein a number of. traveling tractorasuspended hotcoating is again rested on the ground until the coatf ingiloses itsheatand'thereby hardens so that later other tractor suspended cradles may. again lift the coatedtpipe and deposit it into the trench.

In a specific embodiment of the present inventionthe improved cradle structure involves an endless loop circuit of flexible strap slings. disposed transversely of the pipe axis in closelyspaced longitudinalsuccession to present alarge number of;wide bands or slings throughout the loop, circuit having opposite return bends joining upper and lower reaches. The several slings in the closed circuit co-operate for a crawler action on the pipe saddled in the slings-of the uppermost reach, and the individual slings in succession move upwardly through the foremost return bend atthe leading end of the carriage or cradlefrom the lowerv reach to the upper reach for an immobile seating with the pipe during relative pipe and carriage travel, and movedownwardly through the return, bend at the trailing end of the cradle assembly awayfrom pipe engagement in the upper reach and toward the lower reach for recirculation towardthe nose of the cradle. An important feature of. the arrangement is that each sling is hingedly mounted on its loop carrier to swing individually relative thereto on aitransverse pivot axis so that in following the loop circuit its pipe engaging surface always faces upwardly and tends to remain parallel with the pipe axis at all times for insuring a nonangular contact of its wide seating face with the pipesurface, and especially in the approach to and the recession from the pipe surface at the return bend paths. The wide flat face of each sling afiords a continuous bearing contact .with the underside of the pipe in the direction transversely of the pipe, and since the wide straps are in close succession, they combine to form an almost continuous longitudinal bearing area throughout the length of the. upper circuit reach for a maximum load distribution area, .bothtransversely and longitudinally, and a minimum of weight concentration at any point on the pipe un derside.

By. the use of a crawler sling cradle as herein describe'd, the loaclis. spread and the pipe wall protected from deflectiontstrain. More importantly, it enables a length of pipe cradles hold a pipe during thev several work. performing operations in conditioning the pipeline conduit for burial; Fig. 2 is a side elevation partly in section, showing apipe suspending cradle assembly with power drive for bothathe cradle and one of a pair of work performing mechanisms mounted at the ends of the cradle assembly; Figs. 3 and 4 are, respectively, a transverse section and aside elevation on lines 3--3 and 4-4 of Fig.2; Figs, 5 and-6, are a detail transverse section and an end view on an enlarged scale, respectively, of the. guided carrier and its jointed connection at one end of the pipe cradling strap; Fig. 7 is a top plan view on a small scale showing. agroundtraction vehicle and a boom suspended cradlepoweredfrom thettraction vehicle; Fig. 8 is a side elevationshowing succeeding cradles with which are associated pipe coating, Wrapping, and cooling mechanisms; and Fig. 9 isatransverse section as on line 99 oftFig..8.. c p a Referring first to Fig. 1, there is illustrated one-arrangement suitable for handling steel pipe of about twelve inches in diameter. with a wall thickness of aboutone-thirdaof an inch, but the equipment can be adapted for useiwith pipe of other dimensions as regularly employed.1Such pipe in a continuing length, indicated at 10, is 'to be treated and deposited in a ditch or trench 11, and that operation may call for as many as six: tractorsuspended cradles traveling along the lengthof the pipe; Thus, in succession, the first traveling cradle serves to raise the pipe from the ground; the second cradle suspends the pipe, and also mounts forward cleaningbrushes, and an aft priming .mechanism; the third cradle. suspends cleaned and primed pipe against sagging in the. interval between the second and fourth cradles=for allowing,.'dry ingot the priming paint; the fourth cradlesuspendsthe primed pipe, as well as pipe coating and -wrapping mechai nisms in trailing relationto the pipe area being suspended The next cradle mounts a forwardly projecting; cooling spray structure for extracting heat from the. wrapped coating to a substantially nonfiuid temperature, and also cradles the pipethrough the coating whichhas just been hardened, and. the final cradle in the line receivestthe fully treated pipe for lowering it into thetrench 11 A greater or. lesser number of cradles maybe .calledffor, depending upon the size and weight of the pipeand the number of operations to be performed. For example, on small and clean pipe the specifications may omit the cleaning and priming operations and demand only the coating and wrapping cradle and the cooling cradle for the complete operation of lifting, treating, and lowering.

The several carriages or cradle assemblies may be duplicates of one another in so far as concerns the pipe cradling slings, their endless carriers, and the main frames which contain loop guides for the endless carriers. Each carriage has at its top and in substantially vertical alignment with the center of gravity of the asthe reference character 16 and is located centrally of an "H-shaped casting 17 which is best seen in Fig. 4. The opposite terminal ends of both legs of the H-shaped casting 17 have apertured heads 18-18 to receive pins or bolts which extend through the upper ends of a set of four flat plates which extend in transverse planes and are arranged .in two longitudinally spaced pairs so that each pair has corresponding upper ends pinned to the same 'head 18 of the uppermost H-shaped casting 17, as is best 'evident from Fig. 4. The bottom bars of the U-shaped plates 19 extend across from one side to the other of the cradle, and in co-operation with the spaced side legs and .the upper casting 17 afford a central opening through which the pipe extends during normal use of the machine.

Each side leg of the plates 19 has a pair of vertically spaced and inward opening cut-off portions to receive guide tracks comprising a pair of vertically spaced

flat straps

20 and 21. The lowermost strap 20 of the upper straps, as seen in Fig. 3, and the uppermost strap 20 of the lowermost set of straps may be considered as following an endless loop in the longitudinal direction of the machine, as evident by comparison with Fig. 2. Similarly, the outermost straps 21-21 in Fig. 3 appear in Fig. 2 as an endless loop guide extending in the longitudinal direction. The two co-operating guide straps could each be a single loop of strap material, but more conveniently they are formed from a number of separate pieces joined together, and the joining lines conveniently are located at each of the opposite return bends of the loops. To close the outermost sides of the guideways, and more particularly to lend strength and locating support for the loop straps 20 and 21, a pair of outer vertical plates 2222 extend throughout the length of each guideway and are joined to the outer edges of the straps 2t and 21, as by welding. As shown at 2323, each side plate 22 has vertical slots for the projection therethrough of the adjacentportions of the four frame plates 19.

r In each of the endless looped guideways afforded between the vertically spaced straps or

runways

20 and 21 is located an endless carrier in the form of a succession of interpivoted chain links 24 joined in succession by pivot pins, each of which carries wheels or rollers 25 to ride in the endless loop trackway. The link pivot and roller arrangement is shown in detail in Fig. 5, wherein it will be seen that a pair of transversely spaced rollers or wheels 25 have their hubs mounted on antifriction ball bearings 26 fitted to a sleeve 27 held between a nut 28 on a fastening pin 29 and a spacer collar 30 co-operating with the head of the fastening pin 25?. A spacer sleeve 31-between the innermost races of the bearings 26 surrounds the sleeve 27 and affords a pivot bearing for the adjoining, overlapping ends of the co-operating pairs-of chain links 24. Interposed between the head of the fastening bolt 29 and the spacer collar 30 is a tubular bearing sleeve 32 which provides a transverse pivotmounting for a bearing collar 33-which has welded to it a strap 34 which may be of substantially triangular shape, as seen in Fig. 6. Welded to and projecting downwardly from opposite side edges of the pipe 24 are a pair of ears 3535 which are apertured to mount therein a crosspin 36 suitably retained in place, as by means of cotter pins or the like.

Each of the pivotally mounted plates 34 suspends one end of a sling strap 37, preferably formed of a fiexible fabric material and whose opposite end is joined to a like mounting plate 34 of a carrier in the guideway on the opposite side of the main frame, as seen in Fig. 3. Such straps, when they are in the uppermost reach of the loop circuit, can receive the pipe 10 therein and accommodate themselves to various diameters of pipe, and also to bends in the pipe. That is to say, lateral bends in the pipe may result in a relative sidewise swinging of the straps 37 as the carriage travels along the axis of the pipe. As best seen in Fig. 3, substantially more than half of the underside of the pipe is in seating engagement with the flexible sling which conforms itself to the pipe circumference for an arcuate extent approximately between one hundred fifty and one hundred seventy-five degrees for a given pipe diameter with respect to which a particular sling design has been selected. Thus a sixinch wide sling for a twelve inch pipe will afford a bearing face area on the order of one hundred square inches and a cradle assembly having five slings engaging the pipe at all times, presents a support area of around five hundred square inches. These illustrative dimensions will of course vary with sling width and design and the diameter of the pipe being operated upon.

The transverse pivotal connections for the straps afforded by their bearing

members

32 and 33 will insure that the straps will always hang downwardly by gravity, so that their hearing faces in longitudinal planes tend always to remain parallel to the surface of the pipe with which they engage. Thus, as seen in Figs. 2 and 8 in particular, the direction of relative carrier travel may be considered as being toward the left, so that the straps at the trailing end of the carrier will drop downwardly away from the pipe surface as their supporting rollers 25 negotiate the return bend for forward travel through the lower reach to the foremost return bend when the straps are elevated in succession with their faces remaining in a horizontal plane, so that as the supporting pivot pins reach the level of the uppermost reach the strap faces come into nonscraping, flat and nonangular seating relation with the pipe surface or surface of the coating thereon and thereafter remain in stationary or nonscraping seating contact with the pipe as the carrier moves forward with the tracks riding on the roller wheels 25-25.

In connection with the support of the load at the innermost end of the pivot pin assembly, there will be a tendency for the innermost roller 25, as seen in Fig. 5, to bear downwardly on the guide plate 20 while the outermost roller 25 bears upwardly and rides on the undersurface of the plate 21. For restraining any rocking or tilting reaction of the wheel and pivot assembly and for retaining these parts in position, a circular wire or rod 38 is welded on the underside of the track 21 for a lateral bearing against the outermost wheel 25, and a similar wire or rod 39 is welded'to the upper side of the track 20, as seen in Fig. 5, to resist outward force on the innermost wheel 25.

The draft transmitted to the cradle frame through the side boom of the tractor will pull the cradle assembly along the pipe-with the slings in the upper reach of the loop circuit suspending the pipe, and as the movement proceeds, the slings in succession drop away from the pipe at the trailing end of the loop as the endless link chain and supporting rollers travel in the reverse bend to the lower reach and forwardly in the lower reach guideway to the leading end of the machine, where. the rollers are guided upwardly into the upper reach. and theslings again seat on the pipe as the cradle advances. Because of the transverse pivotal mounting of the opposite ends of each sling, they will always tend to hang downwardly with their bearing faces in horizontal planes, sothat as the slings move through both of the reverse bends, their seating faces move into and out of. engagement with the pipe in parallelism with the pipe surface. The slings are preferably constructed so that in the transverse direction, as seen in Fig. 3, their pipe seating. engagement is throughout the entire underside of the pipe and thewidth of the. slings, as seen in Figs. 2 and 8,

is greater than the longitudinal spacing between the slings, and the number of slings in the horizontal reaches of the loop oval affords a large longitudinal length of bearing support, so that the pipe load is uniformly distributed over a maximum of bearing area.

Inmany cases, and especially when. the cradles are conveniently employed for supporting mechanism for performing .work on the pipe,,it will be advisable to supplement. the forward draft of the tractor boom by a positive drive of the endless sling carrier. For that purpose, a. motor may be mounted on the main frame of the cradle with its power output geared to the carrier chain. Rack teeth can conveniently be formed on the chain links for sprocket engagement, and for reducing friction in the drivethe teeth can be in the form of spaced roller sleeves. The rollers or rack teeth 40 are indicatedgenerally in Fig. 2, and in greater detail in Fig. 5. Referring toFig. 5, the rollers 40 are mounted on studs or rivets 41 between a pair of angle brackets 42-42 welded to a plate43 which bridges and is secured, asby welding, to a pair of co-operating chain links 24. Each succeeding. pair of chain links 24 carries a similar mounting plate 43 for a succession of equally spaced rollers 40, andthe latter are for engagement by the teeth of a drive sprocket 44, the lower portion of which projects downwardly through a slot in the upper reach of the guide track 21. The carrier chains on both sides of the machine are similarly equipped with the drive sprocket arrangement for operation in unison, and Fig. 4 shows the drive sprockets 44 fixed toa transverse drive shaft 45 mounted on a transverse axis in.suitable bearings on the main frame. The shaft 45 also has fixed wit a worm wheel 46 (Fig. 2) in mesh with a worm 47 whose shaft is driventhrough gears 48 and 49 from a power shaft 50. This shaft in turn is driventhrough gears 51 and 52 from a motor 53.

1. -A motor especially adapted for-use with the equipment herej involved is of the hydraulic type for response to liquidlflow ina circulating system which also includes a pump 54. This pump 54 (see Fig. 7) is mounted on the tractor 14 and is driven through the usual power take-off mechanism from the tractor engine 15. The pump withdraws hydraulic liquid, such as .thin oil, from-aIsump or supply tank 55 and supplies it through a suitable control valve, through a flexible hose 56 leading to the inlet of the motor 53. The motor outlet is connected by a flexible hose 57 for liquid return to the sump 55. The control valve referred to is under manual control of the tractor operator by means of a hand lever 58, so that the operator can at all times regulate the speed of operation of the drive motor 53 to coordinate or synchronize the traveLof the pipe supporting cradle with the rateof tractor advance. By relieving the tractor of side pull through thelateral boom, the problems of tractor steering are greatly reduced anda straight ahead direction of tractor'travelis facilitated. I

The same sourceof power is utilized for driving accesso'ry equipment forming a part of certain of the succession "of cradles; Thus the cradle which is shown second in line in Eig. 1 andin more detailin the enlarged view, Fig. 1 2,;mc1uae' circular. succession of cleaning. brushes 59 are'to. rotate around the axis of the pipe 10 tobrush andv scrape dirt and corrosion from the, pipe surface. The brushesare mounted in an annular frameGOcarried by forwardly projecting arms, 61 rotatably mounted in a supporting head 62 at the front of the cradle. Connecting brackets or supporting arms 63 detachably secure the mounting head 62 to the main frame of the cradle, and. the rotatable ring which carries the arms 61 is geared or connected by a driving chain 64 with a drive sprocket on the forward end of a driven shaft 65 which is to be connected with the power shaft 50 through 'a con ventional change speed gear box 66 having a manual control lever 67 by which drive gear ratios are. selected The change speed. box 66 enables a range of speed ratios for rotating the cleaning brushes 59 at selected rates intrel'ation to the rate of forward travel in accordance with the work to be done, inasmuch as some pipe surfaces may require more or less cleaning 'and scraping than other pipe surfaces.

The same cradle which supports the driven rotary brushes can be utilized for supporting. the conventional priming mechanism at the trailing end of the cradle. Thus Fig. 2 shows rearwardly projecting supporting brackets 68 on the cradle main frame for carrying anannular pipe surrounding frame 69 and the housing 70, containing the mechanism for applying and spreading a thin film of pritner paint on the surface of the pipe, asv is customary in the practice of coating pipe lines.

There is contemplated the use of a priming paint which is fairly fast drying, and the drying time intervalwill dictate the space between the priming machine and the thick coating machine. That space may be on the order of: one hundred feet or even; as much as two hundred feet, and when heavy pipe is being conditioned it may be desirable to insert a carrying cradle inthe space between the priming machine and the coating machine, as indicated in Fig. 1. This carrying cradle, when constructed. as previously described, will contact the primed pipe surface without harm to the surface, inasmuch as no point on the priming film will have a heavy load concentrated on it, as would be the case with the use of roller cradles ofthe type heretofore employed. Such conventional rollers have concave treads of increasing diameter outwardly from their middle and the variations in circular dimensions of said spaced portions result in different circumferential velocities across the tread and cause a scrubbingor abrasive scraping on at least some part of the pipe surface engaged. No such scraping occurs with the present strap slings and the large area of bearing surface afforded by the strap slings crawling along on the pipesurface supports the pipe without abrasion over a maximum hearing area, and the reduction in the likelihood of injury makes feasible the use of a load'carrying cradle in the space between the priming and coating operations to better insure the suspension of the pipe on a straight line throughout its length of elevation. H

The pipe coating andwrapping mechanisms may be of well known conventional types and are supported by brackets or arms '71 in trailing relation with a pipe supporting cradle, as in' Fig. 8. A supporting frame 72' consists of a pair of longitudinally spaced annular rings, and between them is mounted a dope applying shoe 73 which surrounds the pipe 10 for spreading thereon a thick layer of hot asphaltum. Preferably, the supply ofhot'co atin'g material is pumped directly to the shoe 73 without appreciable' heat loss from a tar kettle andlthrough a de livery'pipe '74-, which includes a flexible conduitor hose connecting the shoe with the tar kettle, shown schematically at '75 in Fig. 1 in trailing relation with thetractorfrorn which the cradle is suspended. The tar kettle storesgand heats the coating material which is fed as a'fiuid having a temperature of around four hundred fifty degrees Fairreheit directly to the shoe in an amount related to the surface area to be covered andthe machine "travel rate to keep down oversupply and heat loss; as occurs-when hot dope does not godirectly to the applying-shoe '73 are a pair of wrapping rolls 78 carried by a rotatable ring 79;. The rotatable ring 79 is mounted in the frame '72 and is geared for rotation from the power supply shaft 50, which in this case extends rearwardly from the motor driven

gearing

51 and 52 previously referred to in connection with Fig. 2. As the machine travels forward 7 fand applies a protective coating on the pipe, the rolls 78 'rot ate about the axis of the pipe and pay out ribbons, 'eitherpaper or felt, in spiral courses to protectively cover the hot tar, and, among other things, the paper coating tends to prevent the hot tar from dripping and protectively envelops the tacky surface.

h T o insure uniformity of coating thickness entirely around the pipe and to minimize the tendency of the hot 'fluid to run or sag from the top and sides to the bottom of the pipe, it is proposed to quench the coating or cause it to give up its heat and fluidity immediately following its application to the pipe. For that purpose and which also enables the hardened coated pipe to be deposited at once in the trench without the setting up period which heretofore has been deemed necessary, a spray cooling arrangement is provided for a quick temperature drop or extraction of heat from the coating and in advance of that pipe supporting cradle next following the coating operation. Water may be employed as the cooling .medium, and its delivery to the coated pipe may be by one or more longitudinally extending pipes 80, each provided with a series of spray nozzles 81 for directing a copious supply of water onto the coated pipe. As seen in Fig. 8, the spray pipe arrangement includes an upper and a lower spray pipe 80, connected at axially spaced intervals by arcuate or annular pipes 82 for communieating the spray pipes with one another. The uppermost spray pipe 8%) has a rearwardly extending arm 83 which is universally connected by a ball and socket joint 84 to a frame mounting bracket which locates the spray frame but allows a certain relative movement in all directions about the ball and socket joint 84. A load supporting spring 85 has one end secured to the arm 83 ahead of the ball joint 84, and has its opposite end joined by an adjustable attachment stud to a frame bracket so that the adjustable connection will enable the position of the spray frame to be adjusted. Normally the adjusted position will set the pipes 8080 on lines parallel to the pipe axis.

' Cooling water enters the spray frame at the inlet connection 86, which is joined by a flexible hose to a supply jp'ump forming a part of a vehicular cooling tower 87 (see Fig. l) which may trail behind the tar kettle 75. After the water has contacted with and extracted heat from the coated pipe, it will drain into a catch basin, shown in Fig. 8 as including a flexible waterproof canvas trap 88 whose sides are secured at their upper ends to approximately the midheight of the annular connecting pipes 8282 and whose bottom wall is inclined rearwardly and is connected to the bottom of the main frame, as a sump. From the sump there leads a pump suction .line 89 which includes a flexible hose running back to the cooling tower vehicle 87, where the heat is extracted from the liquid for recirculation in the cooling system.

The universally jointed mounting for the cooling frame is a feature which will find utility in the event the pipe line has bends in it, inasmuch as the forwardly projecting cooling frame may tend to follow the bend by a swivel movement at the joint and a yielding of the load carrying spring accommodating the bend regardless of the direction of the bend. As a guide for the swivel movement,

four rollers 9 0 having soft rubber treads are provided at circumferentially spaced locations about the pipe and forwardly at some distance ahead of the universal joint 84 and preferably behind the nose or leading end of the spray frame ,(see Fig. 8) The rollers 90 are arranged in upper and lower pairs, with the upper pair secured in a bracket 91 carried by the pipe and the lower rollers mounted in a bracket 92 carried by the lowermost pipe 89. In normal operation the treads of the rollers are all spaced from the pipe surface so as to be out of engagement therewith, with the axis of each roller tangentially related to the pipe axis. As will be seen in Fig. 9, if the pipe bends in any direction, its surface will be engaged by one or the otherof the rollers and the spray frame swings around the pivot 84, keeping the frame and particularly the nozzles away from any sliding or scraping action on the pipe coating. Since the greatest temperature drop is from the hottest coating area and at the very start of cooling from the foremost sprays, there will have occurred a substantial cooling of the coating layer before any rearwardly disposed guide wheel 94 can roll on the cooled outer crust of the coating. By the time the completely sprayed and cooled coating is reached by and rested in the trailing load suspending slings, its temperature will have been lowered to approach hardened solidity, and especially because of the wide bearing area referred to heretofore, there will be little likelihood of pressure deflection of the coating material. Because of the cooling action of the water spray, the corrosion protection of the steel pipe is immediately secure and with the absence of load concentration, any residual plasticity inwardly of the hard crust will be of insignificant consequence as not to shift or permit harmful displacement of the protective sheath.

Accordingly, the cooled, coated pipe may be deposited immediately into the ditch 11 without the customary time delay and additional installation work heretofore prac tieed. For facilitating the lowering in of the pipe and eliminating abruptness of bends as the pipe descends into the ditch, one or more cradles will be used to support the pipe after it leaves the water cooling equipment, as indicated in Fig. 1, and the pipe will be ready for the backfilling operation by which it is buried in the open trench.

A noteworthy advantage of the working equipment here described is that the pipe walls are free from imposition thereon of the heavy weight of the equipment. The entire load is carried by the frame of the pipe cradle as distinguished from the heretofore practice of mounting each of the cleaning, priming, coating and wrapping mechanisms on the pipe itself with the load carrying rollerstracking and bearing on the pipe walls. By relieving the pipe walls of the machine loads, there will be an absence of wall wrinkling and distortion to make feasible the use of thinner pipe walls than otherwise would be required, and thereby enable important cost savings in material for distance pipe lines.

The tar kettle and the cooling tower may be parts of a single vehicle, and the tar and water pumps can be driven from the same power source such as an internal combustion engine. If desired, that engine instead of a tractor engine as before described, may be employed for operating the hydraulic power transmitting system which-operates the driven carriers of the pipe supporting slings.

While the foregoing description has been directed primarily to the preferred embodiment of the invention, it is to be understood that various modifications are contemplated as within the scope of the appended claims.

What is'claimed is:

1. Pipe cradling mechanism, including a power driven, ground engaging vehicle, a pipe cradling structure carried by said power driven vehicle for travel along the length of pipe, said cradling structure including an endless carrier movably mounted fortravel'ina longitudinally extending'loop circuit, pipe engaging slings pivotally conan is atic nested to said carrier on transverse, swing axeswforrcra dIingenga-gemenr. with the pipe-,3. a motor drive connected with the} carrier. and effecting circuit:travel:thereof,v and 'meanscontrollingsaid motor and regulating; the speed of driven carrier travel. to match: thespeedofv travel of said power driven vehicle.

2'. The: structure of claim 1,. wherein: said. vehicle. includessaaside boonrthrough which the cradle structure is adjustaibly-suspended in; laterally oifset rela-tion with the vehicle and: as power supplyfor said motor includes a atpower deliver-y unit mounted on said vehicle and driven from thevehicle, power plant anda. flexible power con.-

ductorl joins thepower delivery unit. with: themotor and flexibly accorrnnodates; position changes of the adjustably suspended cradle structure relative to said. vehicle.

, 3. Pipe: cradling mechanism, comprising a longitudinal succession of transversely extend-ing pipe cradling slings, anrendless looped carrier supporting said slings, eachon aitransverse: pivot axis acomm'odating' individual" swing action thereof to maintain its pipe engaging face: parallel with the pipe surface during loop travel of the carrier, a power. motor: drive connected with: the. carrier to effect travel thereof and: a crawler engagement of the slings with the cradled pipe.

4'. The structure of claim 3 wherein the carrier is comprised of a pair oftransversel'y' spaced, interpivoted link chains and drive transmitting gearing connects the motor with both chains and compels their unison travel.

5. A pipe supporting cradle to be mounted for travel along the length of a pipe, comprising a main frame having transversely spaced side structures receiving the pipe therebetween and carrying transversely aligned guides affording longitudinally extending loop circuits for endless chains, endless chains mounted by said guides of both side structures for loop circuit travel relative thereto, pipe cradling straps having opposite ends supported by said chains, and power drive means operatively drive connected with said chains for the circulation of the chains and the crawler engagement of said straps with a cradled pipe.

6. A pipe supporting cradle to be mounted for travel along the length of a pipe, comprising a main frame having transversely spaced side structures receiving the pipe therebetween and carrying transversely aligned guides affording longitudinally extending loop circuits for endless chains, endless chains mounted by said guides of both side structures for loop circuit travel relative thereto, and a longitudinal succession of flexible flat straps bridging the pipe receiving space and being pivotally joined at opposite ends to said chains on transverse axes so that their pipe engaging faces remain uppermost through the chain loop circuit travel, said straps being longitudinally spaced apart for distances less than their widths.

7. In a pipe cradle of the character described, a pair of transversely spaced endless chains supported in longitudinally extending parallel loop circuits on opposite sides of a pipe to be cradled, and each comprising a succession of interpivoted links and link connecting pivot pins which project inwardly beyond the chain links and in substantially axial alignment with the pivot pins of the other chain, and a succession of flat, flexible straps bridging the transverse space between said chains for cradling a pipe by the straps in the upper reaches of the circuits and each connected at opposite ends to the inner ends of axially aligned link connecting pivot pins of the pair of chains, said connection accommodating free rocking of the straps relative to the chains to present the pipe engaging face of each strap uppermost in the chain circuits.

8. In a pipe supporting cradle of the character described, a pair of transversely spaced endless carriers arranged in an elongated loop circuit having upper and lower reaches and return bends joining said reaches and a series of pipe cradling straps projected transversely across said space and joined at opposite ends to said carriersr hyeonnect ionseonstraining the several.v straps to swing; on: transverse axes. and relative to the? carriers in their-paths through the return bends of the loop' circuit and thereby presenting the straps in planes parallelzand nona-ngularly related to flat seat contact with the: surface: of aupipe cradled. in the upper reachof the loop circuit.

9, In areonduit' supporting cradle wherein an endless carrier. is mounted in a loop circuit having upper and lower reaches and return bends. joining saidreaches, a succession of slings extending; transversely of said carrier" and presenting, conduit receiving cradles in the upper reachof. said loop circuit and pivot connections between the carrier and each. of said slings mount-ing the'slings-for individual rock-ingjaction on-ax'es transverse to the-longitudinal extent .of said. carrier loop: circuit.

10. In a conduit supporting cradle, a series of conduit suspending slings, each comprising a transversely extendingflat strap, an endless carrier suspending each trans.- verse. strap in close succession to one another inthe direction of the length of. the conduit, a support mounting said endless 'carrier for travel through a. loop circuit including upper and lower reaches and opposite endreturns wi-thithe upper reach containing a large number of said straps for simultaneous load bearing. contact with the conduit, and connections between the carrier and the several straps to present the. straps parallel toone another inallpositions throughout the loopcircuit.

11. For conduit installation, a ground engaging vehicle having a source of power, a conduit suspending cradle carried by said vehicle for travel along the length of the conduit with vehicle travel and provided with power driven conduit engaging bearing members, power delivery means having drive transmitting connections with said bearing members and driving the same in conduit traction engagement and power take-ofi' mechanism joining said vehicle power source with said power delivery means and imparting movement through said drive transmitting connections to said bearing members.

12. For conduit installation, a ground engaging vehicle having an engine power take-off device, a conduit suspending cradle carried by said vehicle and including power driven conduit bearing members arranged for traction drive on the conduit concurrently with vehicle travel, power transmitting drive connections between said vehicle power take-off device and said bearing members for driving said conduit engaging bearing members in the propulsion of said conduit suspending cradle, work performing means mounted on said vehicle carried cradle for operation on a conduit coincidentally with forward traction drive thereon by said power driven bearing members, and

-.operating means adjoining said power transmitting drive connections which drive the conduit bearing members and said work performing means to actuate the same.

13. In conduit installation, a ground engaging vehicle having a power take-off device, a conduit supporting cradle suspended from said vehicle for travel with the vehicle and provided with conduit cradling and traction members for drive transmitting connection with said vehicle power take-off device for supplementing vehicle draft on the cradle, and a cooling liquid spray head mounted on the cradle and positioned at the forward end thereof for directing cooling liquid in heat exchange relation to the conduit in advance of conduit engagement by said traction members.

14. For the cooling of a hot fluid coating on a conduit, a ground engaging vehicle, a conduit supporting cradle carried by the vehicle for movement therewith along the length of the conduit and provided with conduit bearing members, a cooling liquid delivery pipe positioned ahead of said bearing members, a pivoted mounting between said pipe and said cradle, resilient load carrying connections between the delivery pipe and the cradle arranged to enable the pipe to swing about said pivot mounting and yieldably maintain the pipe in substantial parallelism with the direction of cradle travel, and a normally inactive spacer on the delivery pipe in forwardly spaced relation to said pivot mounting for temporary buifer engagement with the conduit at those portions in the length thereof which bend or are laterally deflected from any portions instantaneously engaged by said bearing members as the cradle advances.

- 15. Means for cradling a pipe and for crawler engagement therewith comprising, in combination, a pair of sling carriers for receiving the pipe therebetween, support means for said sling carriers arranged for relative move- -ment between the same and the pipe along the longitudinal extent of the pipe, and a plurality of slings rockably supported by said carriers for successively engaging and disengaging the under side of the pipe and'for supporting the same in the relative movement therealong of said support means and the pipe.

-16. Means for cradling a pipe and for crawler engagement therewith comprising, in combination, a pair of sling carriers for receiving the pipe therebetween, support means for said sling carriers arranged for relative movement'between the same and the pipe along the longitudinal extent of the pipe, and a plurality of relatively wide slings rockably supported in their uppermost position about axes located transversely to the longitudinal axis of the pipe for successively engaging the principal portion of the under side of the pipe, said slings having relatively narrow clearance space between adjoining transverse edges of suc- 12 ccssive slings and being many times wider than the intervening clearance space for large area contact as said support means and pipe move relative to one another.

17. A "pipe supporting cradle comprising a pair of transversely spaced supports arranged to receive a pipe in the space therebetween and for the relative travel of the pipe and supports in the direction of the axis of the pipe, a pair of endless carriers mounted by said supports for travel relative thereto through a circuit parallel to the pipe axis, a succession of transversely disposed flexible sling straps suspended in substantially U-shape from said carriers for ascent to the upper portion of said circuit and pipe seating engagement without movement on the pipe surface engaged thereby and for descent away from the pipe to the lower portion of said circuit, and swivel means swinging said straps on the carriers on axes transverse to the pipe axis for dependent suspension of the U-shaped straps and the swinging thereof to present their wide seating surfaces in planes parallel to the pipe surface throughout their circuit travel.

References Cited in the file of this patent UNITED STATES PATENTS 1,941,002 Harrison Dec. 26, 1933 2,041,337 Harrison May 19, 1936 2,287,825 Postlewaite June 30, 1942 2,583,819 Cummings Jan. 29, 1952