US3193901A - Apparatus for making cast-in-place pipe - Google Patents

Description

July 13, 1965 H. 5. LEE EI'AL 3,193,901

APPARATUS FOR MAKING CAST-IN-PLACE PIPE Filed NOV. 20, 1961 5 Sheets-Sheet 1 INVENTORS: #525527 .5. LEE BY JAMES F. O'CQA IVEQ A T7024 5 Y5 July 13, 1965 H. 5. LEE ETAL 3,193,901

APPARATUS FOR MAKING CAST-IN-PLACE' PIPE Filed Nov. 20. 1961 5 Sheets-Sheet 2 INVENTORS. 1 /525527 $.LEE JAMES F. O'CO/VJVEZ July 13, 1965 Filed Nov. 20, 1961 A H i? H. 5. LEE EI'AL APPARATUS FOR MAKING CAST-IN-PLACE PIPE 5 Sheets-Sheet 3 INVENTORS.

#525527 3. LEE JAMES F. O'CO/VA/EE ATTOE/YEYS July 13, 1965 H. 5. LEE ETAL APPARATUS FOR MAKING CAST-IN-PLACE PIPE Filed Nov. 20. 1961 5 Sheets-Sheet 4 INVENTORS: #525527 .5. LEE BY JAMES F OCO/VNEE A TTOR/VEYS July 13, 1965 v v H. 5. LEE arm. 3,193,901

APPARATUS FOR MAKING CAST-IN-PLACE PI-PE Filed Nov. 20, 1961 5 Sheets-Sheet 5 INVENTORSI #525527 .9. LEE

BY JAMES E fl'COlVA/i? ATfOEA/EX) United States Patent APPARATUS FOR MAKING -CAST-IN-PLACE FIFE Herbert S. Lee, Los Alamitos, and James F. Ofionner,

Long Beach, Qalii, assignors to American Pipe and Construction 630., South Gate, Calit'., a corporation of Delaware Filed Nov. 20, 1961, Ser. No. 155,531 14 Claims. (6i. 25--32) This application is a continuation-in-part of copending application, Serial Number 100,457, April 3, 1961, now abandoned.

This invention relates to apparatus for producing castin-place pipe. The invention more particularly involves the utilization of an inflatable tubular envelope that defines a core member for supporting cementitious material until it takes a permanent set.

Although the use of inflatable core members is not new, the methods and apparatus previously employed have not proven to be entirely satisfactory, primarily since the cost of the inflatable core members was high compared with their life expectancy. Furthermore, pipe conduits formed by the prior art systems tended to be of variable thickness, especially where the cast-in-place pipe diameter was of relatively large size. In many instances this was the result of an inability to retain the form member submersed at a uniform level within its cementitious encasement, for, as might be expected, these form members tend to float or be buoyed up by the relatively heavy cementitious material.

Briefly, the present invention contemplates apparatus that can utilize an inflatable tubular envelope made of thin, pliable and inexpensive material. The envelope is initially sealed and anchored at one end by a first bulkhead, through which the envelope is inflated with fluid pressure medium. A second bulkhead is provided at a spaced distance from the first bulkhead; and while this second bulkhead is advanced, increasing the inflated length of the envelope, the newly inflated sectional lengths are progressively encased with cementitious material. By virtue of this progressive system of inflation and encasement, the cementitious material can be gradually deposited upon the envelope. Since the entire inflated surfaces of the envelope may be easily confined by the bulkheads and the cementitious material deposited thereon, there is little danger of rupturing a portion of a relatively thin envelope. Moreover, since the encasement process is continuous and progressive, each newly inflated section of the envelope is capable of being accurately positioned and supported while being encased with the cementitious material. Inasmuch as the fluidity of the cementitious material may be regulated so as to take a set soon after it is placed around the envelope, only the most recently encased portion of the envelope need be held against floatation. Thus, no special restraining braces are required for holding the inflatable envelope against the forces of buoyancy.

This invention also contemplates and provides new and different forms of apparatus for encasing an inflatable tubular envelope with cementitious material. It will be readily apparent that new forms of apparatus have been discovered and devised for sealing oil the ends of the envelope by bulkhead means. Also, a movable bulkhead is provided that is adapted to be advanced along the bottom surface of a trench during the process of material encasement. Novel forms of apparatus are also provided for extruding cementitious material around an inflatable tubular envelope as a movable bulkhead is simultaneously and continuously advanced.

Therefore, it is to be understood that one object of this invention is to provide new forms of apparatus for pro- F4 3,193,931 e Patented July 13, 1965 ducing cast-in-place pipe, said apparatus utilizing an inflatable tubular envelope.

Another object is to provide apparatus for producing cast-in-place pipe including an inflatable envelope, having means defining a movable bulkhead for engaging said envelope and sealing off one end thereof, and whereby said bulkhead means can be advanced along a path, thereby increasing the inflated length of said envelope.

It is another object of this invention to provide apparatus of the kind described in the above objects and further including means for extruding a cementitious conduit around the inflatable envelope as said movable bulkhead is advanced.

Another object is to provide apparatus of the kind described wherein said inflatable envelope is packaged in a cartridge from which it is continuously withdrawn and extended as the apparatus is advanced.

Another object of the invention is to provide apparatus of the kind described including a cartridge comprising a cylindrical sleeve having a coaxial center mandrel supported from a sealing bulkhead, andfurther wherein an inflatable envelope is accordion folded upon said mandrel within said sleeve.

A further object of the invention is to provide apparatus of the kind described wherein said inflatable envelope is formed of relatively thin, pliable material that may be folded.

Other objects of this invention will become more readily apparent in view of the. following description and the accompanying drawings.

In the drawings, forming a part of this invention and in which like parts are identified by like reference numerals throughout the same,

FIG. 1 is a longitudinal vertical section of one form of apparatus for producing cast-in-place pipe in accordance with the practice and teaching of this invention, certain parts being shown in elevation;

FIG. 2 is a partial top plan View of the apparatus shown in FIG. 1;

FIG. 3 is a section taken on lines 33 of FIG. 1;

FIG. 4 is an enlarged horizontal section of the stationary bulkhead shown in FIG. 1;

FIG. 5 is a section taken on lines 55 of FIG. 4;

FIG. 6 is an enlarged detail section taken on lines 66 of FIG. 5;

FIG. 7 is an enlarged section of a portion of the ap-' paratus shown in FIG. 1;

FIG. 8 is a perspective and detail view of a pinch roller assembly that forms a part of a movable bulkhead;

FIG. 9 is a longitudinal vertical section of the apparatus shown in FIG. 1 during the process of anchoring the movable bulkhead and disassembling said bulkhead from the material encasement apparatus;

FIG. 10 is an elevational view of the form encasement apparatus of FIG. 1 in a dismantled condition ready for cleaning;

FIG. 11 is a longitudinal vertical section of a second embodiment of apparatus for producing cast-in-place pipe which utilizes an envelope cartridge, some parts being shown in elevation;

FIG. 12 is an enlarged detail view of the envelope cartridge assembly shown in FIG. 11;

- FIG. 13 is an enlarged detail view of one portion of the cartridge assembly, showing the way in which the inner end of the envelope is sealed; and

FIG. 14 is a front end elevation of the cartridge assembly mounted upon its supporting skid. I

Referring to FIG. 1 in particular, there is shown a novel arrangement of apparatus for producing cast-in-place pipe in a trench and generally comprising an inflatable tubular envelope 10, a stationary bulkhead 11 with air compressor means 12, a imovable bulkhead 14 forrextruding cementitious material around the envelope 10, and power-drive means 15 for advancing bulk head 13 and extrusion apparatus 14. a

c The inflatable tubularenvelope 10 may be'formed of I relatively thin pliable material such as plastic. While perhaps'many forms of plastic materials may be used, the product known as Mylar, manufactured by Du Pont, has been satisfactorily employed. The, wall thickness of the envelope may be extremely thin as compared with liners 13, extrusion apparatus 7 by the pinch rollers as the envelope passes through slotted opening 44' Inasmuch as the envelope Willbe forced against the wall member 42 by the internal and confined fluid pressure, and since the envelope is drawn frictionally across the wall member, it is desirable that surface 43 be polished to reduce frictionaldrag and abrasive contacts which would tend to rupture the envelope.

conventionally utilized in form pouring. For'exarnple,

an inflatable envelope having a'diameter of 24' may be formed from material havin'g a wall thickness of only ;O1". This size of envelope and material is given only a by way of example to illustrate that'the envelope material may be relatively thin and expandable.

The useof lateral guide rollers 47 has also been used to advantage in an arrangementas shown in FIGS. 7 and 8. Rollers-47 serve to direct the envelope into the slotted opening 44. a. Y

It is to be noted that this inventionfurther contemplates a novelassembly of extrusion apparatus 14 for continu- Envelope is fluidly sealed at a fixed or stationary end y by bulkhead 11, as shown in FIGS..46} A pre-cast sec- 7 tion of pipe 20, or other form member having substan-- ftially the same internal circumference asthe exterior cir-f cumference ofthe envelope'10; is initially used to begin the process oflpipe manufacture.- Pipe section is re- 1 strained from backward'movement by a bracing means comprising a pair of timbers 21 and a screw jack 22. One timber member is placed on either side of the'trench 23.within-which the pipe is to be cast, and the screw jack is used to spread the timbers apart, forcing them into the walls of the trench. Each imber provides'a surface portion laterally inward of the trench against which the cast-in-place pipe section is placed, said timbers restraining further rearward movement of the pipe section.

- Bulkhead 11 is comprised, of a wall member 24 having a peripheral rim ZSdefining an exterior channel, and an inflatable tube 26 or other expan-sible means is disposed peripherally thereof; Tube 26 resembles the tire of a vehicle having a .valvejstem 27 protruding inwardly through rimZSL An elastic ring 28is used for securing 7 envelope 10 peripherally of rim 25,bef0re bulkhead 11' is placed within a pre-cast pipesection; and four quadrantly spaced fastening screws 29 are used for anchoring the bulkhead to the pre-cast pipe. I

ously and, progressively forminga cementitious. pipe around the inflated portion of envelope 10. The extrusion apparatus comprises a" slip form type of machine that is constructed'with :detachable front and rearward skid 1 sections 59 and 51, verticallydivided as shown in FIG. 10 r and connected by pins 52. The rearward section 51 defines a. tubular slip; form 53 having a hopper portion 54 communicating with a forward interior portion-thereof.

' The front skid sectionSt) is attached to power-drive means 15 and also supports a tubularauger or'screw 55 upon a fixed, elongated sleeve member. 56. 'Sleeve member 56 is supportedat one end, having its'rearward portion cantilevered coaxially'with respect to tubular slip form 53. Bearing surfaces 57and58- are provided exteriorly of sleeve member 56 and complementarybearing surfaces 59 and 6t areprovidedinteriorly'of the auger. Additionally, a thrust bearing and extension sleeve 61 is supported rearwardly of the, auger from the end' of sleeve member56. V

, The bearing surfaces 57,58, 59 and 60 are lubricated from a central supply source through a conduit. 62.

When the front and rearward sections 50 and 51 are assembledf'auger 55 is coaxially disposed within tubular slip form 53. The auger transports cementitious material Wall member '24 contains a pair of pressure relief valves 1 30, each valve comprising a valve'plate 31 reciprocally 1 mounted ona valve stem 32frorn a cross arm support 33 and biased toward a closed positionbya helical compres sion spring 34. A pair of lock nuts 35 is'threaded upon the valve stem, andby rotatably adjusting their axial position thecompression force of the valve spring'srnay be controlled. It will be apparent that the relief valves are employed to limit thefluid pressure force applied withinv envelope 1t).

Compressor means 12, comprising a gasoline powered 7 engine 36 and blower 37, is fluidly connected to theinteriort of envelope 10 by a flexible conduit 38 through an opening in wall member 24. A second conduit line 39 provides fluid communication between'the interior of the envelope and a manometer 40, which indicates the instantaneous fluid supporting pressure within said envelope. I

As indicated above, envelope'ltl is sealed off at its other end by a movable bulkhead 13; and while the bulkhead 13 is .advanced along trench 23, the inflated length of the envelope is progressively increased. The deflated portion of envelope 10, i;e., the portion forward ofbulkhead 13, maybe rolled upon a reel 41 and carried in ad vance of the bulkhead. r

Bulkhead 13 comprises awall' member 42 having. a

n from the hopper portion 54, feeding and'extruding the material around an interior slip form sleeve 63. Bulkhead 13,'sleeve 63 and extension sleeve 61 are'brought into a unitary assembly by a plurality of'tie rods 64 that are pivotally and detachably connected to ears 65 attached interiorly of sleeve 45; Each tierod extends through .the fixed sleev'e member 56 and is detachably secured to a clevis bracket 66 by means of nuts 67. The clevis brackets are. rigidly mounted to the front section and,

accordingly, the extrusion apparatus 14 and bulkhead'13 move asaunitary assembly.

a It will be seen that the reel 41 is" also mounted upon the front section 50, and the envelope material extends interiorly through sleeves 63, Hand elongated, sleeve member 56.

' Auger is rotatably operated-by the power drive means 15 through a transmission comprisinga drive shaft 6S,'a sprocket 69, drive chain and a driven sprocket 71. Shaft 68-is journaledupon bearings 72 and 72a mounted upon the front. section 54 and sprocket 69 is V keyed'to the shaft as shown in FIG; 7; The driven sprocket 71is attached peripherally of the auger by means of a plurality o'fsetscrews 71a.

Drive means 15 com'prises a vehicular frame 73 that is connected to the front section 50 by three pin conconcave, polished surface43 and a centrally slotted open-1 v ing 44. Wall member 42 is mountedwithin a cylindrical slip form sleeve 45that; serves toprovide a continuation 'nections 74, 75' and 76. Frame 73 is primarily sup ported upon a high traction tire 77 which isused for propelling the 'casbin-placeapparatus along the trench.

. The drive means 15 also includes 'a gasoline engine '73, a hydraulic pump 73 and two hydraulic motors 8t) and [81. Hydraulic motorSG is used for driving the high traction tire '77, andmotor 81 operates the auger drive shaft 6fl through age'ar box 82 and a detachable shaft connection 83. As shown and described, the drive means is formedasa power package that may be used with various size machines, grouped as to their power requirements. Thus, it will be' seen that the entire drive means can be' detached'from one extrusioh apparatus by re moval of pin connections 74, 75 and 76, and detaching shaft connection 83. Then the same drive means can be connected to an extrusion apparatus of different size but having identical connections. This structural arrangement reduces the number of power units required to operate a full range of machines.

It is to be understood that while a preferred form of apparatus contemplates a self-propelled machine having high traction tire, nevertheless the more fundamental principles of this invention can be used with machinery that is moved longitudinally of a trench by a winch-powered cable. In such instances an extrusion apparatus of the kind described is utilized, then separate power mechanism may be provided for rotating the auger.

To start the process of casting a pipe in place, the piece of pre-cast pipe 20, or a metal form, is placed within the trench 23. Timbers 21 and jack 22 are then installed for restraining the pipe against backward movement. The extruding machine, including movable bulkhead 13, is placed adjacent to the pre-cast pipe section with the slip form sleeve 45 actually disposed within said pipe section. Envelope is then pulled through the machine and pre-cast pipe 20 whereupon stationary bulkhead assembly 11 is secured thereto by elastic ring 28, said envelope extending over the tube 26. The bulkhead assembly is slipped into the rearmost end of the pre-cast pipe, and while supported in a vertical position, tube 26 is inflated forming a fluid pressure seal. After inflation of tube 26, which centers the bulkhead 11 relative to pipe section 20, screws 29 are tightened to secure the bulkhead to the pipe section and thereby preventing the fluid pressure that is to be applied within envelope 10 from blowing the bulkhead out of the pipe section. The apparatus is now conditioned to begin operation.

Blower means 12 is started, supplying air pressure into envelope 10 and causing an inflation thereof between bulkheads 11 and 13. The amount of air pressure used will necessarily depend upon the diameter of pipe being cast as well as the wall thickness of the pipe. However, an internal pressure of 6 oz./sq. in. has been effectively used in casting a pipe of 24" internal diameter. Inasmuch as the entire envelope is contained by the more durable and rigid bulkhead surfaces and the inten'or confines of the pre-cast and cast-in-place pipe sections, there is no tendency for the envelope to be enlarged beyond its normal inflated size, provided, of course, that the internal pressure does not become excessive. For this reason, and also to prevent rupturing of the envelope, pressure relief valves 30 are utilized to insure that a near constant pressure level is maintained. The pressure level may be checked by the manometer 40.

At this point of operation the movable bulkhead 13 and extrusion apparatus are ready to be advanced. From a control panel 84 mounted to the rearward section 51 of the extrusion machine, operation of the auger screw 55 is begun, taking freshly prepared concrete from the hopper 54 and extruding it around slip form sleeve 63. As the extruded pipe material emerges from the end of tubular slip form 53, which is initially placed in approximate abutment with the pre-cast pipe section 20, power is supplied to the high traction tire 77 and the movable bulkhead and extrusion apparatus are advanced. The speed of forward movement is made equal to the rate at which pipe material is extruded. Thus, envelope 10 is not subjected to any abrasion from the concrete; and the only abrasion encountered by the envelope is that which results from the contact with the polished surface 43 of bulkhead 13.

The machine may be continuously advanced until the length of a selected run is completed, as may be determined by the length of the inflatable envelope, or the size of reel 41. For convenience of operation, it is contemplated that the envelope material may be stored upon reels of 1000 feet capacity.

After a given run has been completed, the extrusion machine 14 and drive means 15 can be removed from the trench for cleaning although the most recently extruded pipe sections have not taken a permanent set. Of course, the movable bulkhead 13 must remain in the trench until the concrete has set sufliciently for the arch portion of the pipe to stand without the aid of air pressure. It is for this reason that the bulkhead 13 is detacha'oly formed from the extrusion apparatus 14.

To remove the extrusion apparatus, the forward ends of tie rods 64 are initially disconnected from their respectiveclevis brackets 66 and an extension rod is added to each rod forward of the drive means, as shown in FIG. 9. Each extension rod is then secured in the trench and in advance of the drive means by bracing means 86, such as employed for restraining the cast-inplace pipe section 20 from backward movement. Obviously, bracing means 86 is secured in a manner to prevent the movable bulkhead 13 from being moved forwardly by the air pressure within envelope 10 after the extrusion apparatus is removed. The length of the extension rods 85 need not be long but suflicient to allow the extrusion apparatus to be advanced about four feet. With bulkhead 13 secured in place, the extrusion por tion of the machine is propelled forward about three feet, leaving the bulkhead in the extruded pipe and forming an access space between slip form sleeve 45 and sleeve 63. Braces are now applied between the slip form sleeve 45 of bulkhead 13 and the trench, said braces being similar in type to that shown and designated as bracing means 86. Once bulkhead 13 is secured to the trench, the tie rods 64 are disconnected from their respective ears 65, then tie rods 64 and extension rods 85 are removed from the trench. In this condition the extrusion apparatus 14 and drive means 15 may also be removed from the trench. By removing the four pivot pins 52, the front and rearward skid sections 50 and 51 may be separated for cleaning as shown in FIG. 10.

After a suflicient time has elapsed for the concrete pipe to take a set, the air compressor 12 may be turned 011 and the pipe exposed to atmosphere. Bulkheads 11 and 13 and envelope 10 are then removed from the pipe, and an end joint is provided.

A further development of the basic inventive concept is illustrated in the embodiment of FIGS. 11-14. The extrusion apparatus 14a is substantially identical to that previously described. The only major difference is the elimination of the sleeve extension 63 and the substitution of an envelope cartridge assembly 113 in place of the bulkhead 13.

Cartridge assembly 113 comprises a cylindrical sleeve 114 having an enlarged, conical-shaped end and including a tubular center mandrel 115 supported from a bulkhead 116. The inflatable envelope 10 is disposed within the cartridge assembly, being accordian folded, as shown in FIGS. 11 and 12; and the inner end of envelope 10 is sealed by bulkhead 116 in the manner shown in FIG. 13, where the envelope is initially passed around the periphery of the bulkhead before said bulkhead is secured in abutment with a flange portion 117 on the end of sleeve 114. I

Angularly spaced ears 118, which may be formed integrally with the flange portion 117, extend radially inward beyond said flange portion, allowing the bulkhead to be secured thereto by studs 119 and nuts 119a.

Referring to FIG. 13, the flange portion 117 may be mounted within sleeve 114 by a plurality of screw members 120 inserted radially through the sleeve. It will also be seen that a resilient gasket 121 is utilized to more effectively seal the end of envelope 10 between flange portion 117 and bulkhead 116.

Furthermore, in view of FIG. 12, it will be noted that sleeve 114 is provided with a peripheral flange 122 at or near the point where the end of the sleeve enlarges.

Flange 1'22 serves to limit the forward movement of the sleeve relative to the extrusion apparatus as the cartridge 7 7 V sleeve is placed within the slightly greater diameterthan the inner diameter of sleeve member 56. Cartridge assembly113 is loaded into sleeve member 56 from the rear and is securedtherein by the connection of a retainer bar 123, as best shown in F-IG.

14. Bar 123 may be fastenedto the same stud mem- "bers 119 which connect bulkhead 116 to flange portion 117, but by the supplementary use 'of nuts 111k. 'The ends of bar 123 are sufficiently extended to overlap the forward end of sleeve 56,,thereby preventing a rearward,

removalof the cartridge until the. bar is itself removed.

auger 55, said flange being of Thus, flange 122 and the retainerbar 123 confine cartridge assembly113 within sleeveSd.

As with the first described embodiment it is desirable that the extrusion apparatus should be remov'able'from the trench for cleaning although the most recently cast pipe has not hardened sufiiciently to be self-supporting. The embodiment of FIGS, 11-14 utilizes a novelsystem for removing cartridge assembly 113 while the last-poured pipe section is hardening. Of course, it'is again necessary that the pressure within envelope 10'be maintained if the cartridge is removed before the last-poured ma? terial has solidified, and'the system shown is inherently capable of performingthis function. In the initial setting up of the apparatus, a cable 124 is hooked to the stationary. bulkhead 11 by means of a hook attachment 125 V any air which may escape from small leaks without adversely affecting the pressure to be maintained.

In operation, the extrusion apparatus 14a with envelop cartridge assembly 113 is advanced along the trench; and

as the machine is advanced the infolds of the envelope are extended and'inflated. Cable 124 is simultaneously lengthened, being drawn off roll 126 and through the bulkhead 116. Now, as the machine nears the end of its intended run, for example, when the envelope ltl is nearly 'fully extended, a cable clamp 127 is applied. to;

cable 124 in frontof bulkhead 116. 7 Cable clamp 127 will be drawn into abutting engagement with the bulkhead, thereby preventing a further extension of thecable.

126 may be removed from'itssupport onthe extrusion At this point, and before any tensionis applied to the. cable, the retainer bar 123 is removed; and either roll apparatus or the cable may be disconnected from the roll itself. The extrusion apparatus 14a may then be ad-i vanced and cable 124 will hold the cartridge assembly. 113 in.place.

' While the last-laid pipe section is hardening, the extrusion apparatus 14a may be dismantled and cleaned in i the same manner shown in FIG. 10. It will be under stood that the cartridge assembly 113 will remain in place in the trench until envelope ltlcan be de-pressurized' after which time the cartridge is removed and reloaded with another envelope. j e

* It is to be understood that the forms of the'invention herewith shown and described are to be taken as preferred examples thereof. Although various changes may be made without departing fro'm'the spirit of the invention or the scope er the attached claims, each of such changes is contemplated and is to invention. p

Having thus described ut invention, what we desire to secure by Letters Patent is: v

1. Apparatus for producing castsin-placejpipe comclaim and be regarded as part of this tionary end extending rearwardly from said skid and a sealed front end disposed within saidrcartridge, means for inflating said' tubular envelope intermediate said sealed ends with sufficientpressure to sustain a layer of cementitious' material, and means supported from said skid'for progressively encasing said envelopewith inaterial as said skid and cartridge are advanced;

2. The apparatus of claim l'wherein said encasing means comprisesextrusioh apparatus adapted for being operated to produce extruded pipe at a linear rate equal to the forward movement of said skid, said extruded pipe having approximately the same internal shapeand size as the exterior shapeand size of said tubular envelope. 7 3. The apparatus of claim 1 wherein said cartridge comprises a cylindrical sleeve having a coaxial center mandrel'supported upon a substantially horizontal axis, and wherein uninfiated portions of said envelope are accordion folded upon said mandrel within said sleeve.

4. The apparatus of claim 1 and further including means of limited extension.interconnecting the stationary and front ends of said envelope, said means allowing the inflated length of said envelope to be increased up to the point of limited extension.

5; The apparatus of claim 1 wherein said inflatable envelope is compactly arranged in concentric accordion folds and disposed Within said cartridge,

6. Apparatus for producing cast-in-place pipe comprising: a tubular skid having a hopper communicating with a forward interior portion. thereof, a tubular screw coaxially disposed within said tubular skid and adapted for feeding and extruding material from said hopper rearwardly through said 'skid,means for rotating said screw,

' means defining an envelope cartridge supported from said teriaL'and means for advancing said skid and forward bulkhead, at a linear rate substantially equal to the rate at which material is being extruded by said screw.

H '7. Apparatus for producingcast-in-place .pipe comprising: a tubular skid having a hopper communicating with a forward in-terior'portion thereof, a tubular screw coaxially disposed within said tubular skid adapted for feeding and extruding material fromsa-id hopper rear- Wardly through saidskid, means for rotating said screw, an envelope cartridge supported from said skid centrally of said screw, a folded but inflatable tubular envelope disposed within; said cartridge, said envelope having .a sealed stationary end extending rearwardly from said skid and a sealed front end disposed within said cartridge, means for inflating said tubular envelope intermediate said sealed ends with sufficient pressure to sustain a layer ofcementitious material, and means foradvanc'ing said skidand envelope cartridge at a'linear rate equal to the rate at which material is extruded by said screw.

8..The apparatus of claim, 7 and further. including means of limited extension interconnecting the sealed stationary end and the sealedfront end of said envelope, said means allowing the inflated length of said envelope to be'increased up to-thei point of limitedextension.

- '9. The apparatus of claim 8 wherein said :means of limited extension comprises 'a cable that extends through anopening in one sealed end of said envelope; and further includes a cable clamp larger than said opening, said cable clamp being attachable to'said cable for engaging said one sealed end and preventing further advancement prising: askidadapted to be moved longitudinally along the ground, an envelopecartridge supported from said. skid, a folded but inflatable. tubular envelope disposed within said cartridge, said envelope having a sealed staof 's'aidenvelope cartridge.

10. The apparatus of claim.9 and'further including a "cable reeladapted for feeding out said cable upon advancement of said envelope cartridge until said cable clamp is attached to said cable and engages said one sealed end.

11. Apparatus for producing cast-in-place pipe comprising: a tubular skid having a hopper communicating with a forward interior portion thereof, a tubular screw coaxi-ally disposed within said tubular skid and adapted for feeding and extruding material from said hopper rearwardly through said skid, means for rotating said screw, an envelope cartridge coaxially disposed within said tubular screw, said cartridge including a cylindrical sleeve, a conical end, and a coaxially disposed mandrel, said conical end extending from said cylindrical sleeve to said tubular screw, a folded but inflatable tubular envelope disposed within said cartridge, said envelope having a sealed stationary end eXtending rearwardly from said skid and terminating at a first bulkhead and a sealed front end disposed within said cartridge at a second bulkhead, means for inflating said tubular envelope intermediate said bulkheads with sufiicient pressure to sustain a layer of cementitious material, and means for advancing said skid and envelope cartridge at a linear rate equal to the rate at which material is extruded by said screw.

12. The apparatus of claim 11 and further including means of limited extension interconnecting said bulkhead-s, said means allowing the inflated length of said envelope to be increased up to the point of said limited extension.

13. The apparatus of claim 12 wherein said means of limited extension comprises a cable that extends through an opening in said second bulkhead of said envelope, and

further includes a cable clamp larger than said opening, said cable clamp being attachable to said cable for engaging said second bulkhead and preventing further advancement of said envelope cartridge.

14. The apparatus of claim 13 and further including a cable reel adapted for feeding out said cable upon advancement of said envelope cartridge until said cable clamp is attached to said cable and engages said second bulkhead.

References Cited by the Examiner UNITED STATES PATENTS 291,849 1/84 Howson 32 830,204 9/06 Boyle 25-32 857,584 6/07 Boyle 25128 857,586 6/07 Boyle 2532 857,588 6/07 Boyle 25-32 1,348,332 8/20 Stremel 26431 1,636,243 7/27 Rasmussen 25--l27 2,125,025 7/38 Huckfeld-t et al 1856 2,206,410 7/40 Lolly 25128 2,878,544 3/59 Dilday 2532 2,950,702 8/ Ferguson et al. 25127 FOREIGN PATENTS 570,970 7/45 Great Britain.

360,146 11/31 Great Britain.

13,054 1/ 12 Great Britain.

ROBERT F. WHITE, Primary Examiner.

ALEXANDER H. BRODMERKEL, Examiner.

Claims (1)

1. APPARATUS FOR PRODUCING CAST-IN-PLACE PIPE COMPRISING: A SKID ADAPTED TO BE MOVED LONGITUDINAL ALONG THE GROUND, AN ENVELOPE CARTRIDGE SUPPORTED FROM SAID SKID, A FOLDED BUT INFLATABLE TUBULAR ENVELOPE DISPOSED WITHIN SAID CARTRIDGE, SAID ENVELOPE HAVING A SEALED STATIONARY END EXTENDING REARWARDLY FROM SAID SKID AND A SEALED FRONT END DISPOSED WITHIN SAID CARTRIDGE, MEANS FOR INFLATING SAID TUBULAR ENVELOPE INTERMEDIATE SAID SEALED ENDS WITH SUFFICIENT PRESSURE TO SUSTAIN A LAYER OF CEMENTITIOUS MATERIAL, AND MEANS SUPPORTED FROM SAID SKID FOR PROGRESSIVELY ENCASING SAID ENVELOPE WITH MATERIAL AS SAID SKID AND CARTRIDGE ARE ADVANCED.

Images