Device and method for trenchless replacement of underground pipe
The basic features of the invention include a pipe parting mole, a length of cable that is engagable to the mole, a cable pulling device and a cable pulling device engagement means that provides a mounting structure for the cable pulling device. The cable pulling device engagement means generally includes a reaction plate and a structure for removably engaging the cable pulling device therewithin. A cable pulling frame may be advantageously used to facilitate the removal of the cable from a relatively small hole that is created at the pulling end of the pipe.
The present invention is a continuation application of copending U.S. patent application Ser. No. 10/337,934, filed Jan. 6, 2003, which is a continuation U.S. patent application Ser. No. 09/939,084 (U.S. Pat. No. 6,524,031) filed Aug. 24, 2001, which is a continuation of U.S. patent application Ser. No. 09/350,948 (U.S. Pat. No. 6,305,880), filed Jul. 9, 1999, which is a continuation-in-part application, based upon and claiming priority to pending International Patent Application Serial No. PCT/US98/00266, filed Jan. 9, 1998 by the inventors hereof; which application claims priority to U.S. Provisional Patent Application Ser. No. 60/035,174, filed Jan. 9, 1997 by the inventors hereto to which priority is claimed.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates generally to devices and methods for the trenchless replacement of underground pipes and more particularly to pipe splitting devices and cable pulling devices and methods for splitting and expanding existing pipe to facilitate the replacement thereof with new pipe.
2. Description of the Prior Art
Trenchless technology for the replacement of underground pipe is not new, and the standard equipment and methods generally used are well known. This standard equipment for this technology is very large, heavy, and therefore requires additional large, heavy duty equipment for the transportation to, and the placement thereof on site, and the operation thereof on site.
There are several methods of propelling a pipe bursting, and/or cracking and expanding device, and pulling a new pipe through an existing pipe. The most commonly used methods are large cable winches, and/or rod pushers or pullers that are usually hydraulically powered, and often used with a pneumatic percussive device helping to drive the pipe breaking device. Winches give continuous motion during pulling, while rod pushers/pullers generally give cycled motion in which they pull, then a rod must be either added or removed, before the return stroke, and next pull stroke. Sometimes rod pushers are converted to cable pullers, eliminating the need for rod removal.
Winches and rod pushers/pullers that can produce pulling forces of up to 75 tons can themselves weigh 2 to 5 tons and must be handled and placed in position to pull; they are powered by correspondingly heavy duty equipment, cranes, trucks, and back-hoes, etc. They also need large excavations, such that the support equipment can take up enough room so as to create traffic problems and even require street closures.
This also means that only large companies with large financial resources can afford the equipment necessary to replace underground pipes, and because the costs and maintenance on this equipment can be high, their prices are also high. Therefore the use of this prior art trenchless technology has been limited mainly to the 6 inch or above size pipe of municipal or corporate supply and sewer lines, and is used mainly by large contractors.
SUMMARY OF THE INVENTIONThe basic components of the invention include a pipe parting mole, a length of cable that is engagable to the mole, a cable pulling device and a cable pulling device engagement means that provides a mounting structure for the cable pulling device. The cable pulling device engagement means generally includes a reaction plate and a structure for removably engaging the cable pulling device therewithin. A cable pulling frame may be advantageously used to facilitate the removal of the cable from a relatively small hole that is created at the pulling end of the pipe.
The equipment of this invention, is of modular design and needs no bolting, or tools to assemble. It will fit into an excavation hole that is 2 feet wide and 3.5 feet long, for the small pullers (24 tons) and 2′×4.5 feet long for the largest puller (75+tons) the entrance hole for the replacement pipe need be only as long as the radius bend, that the polyethylene pipe size used, requires.
The components of the present invention can be easily built in several sizes according to the strength of the cable to be pulled, and componentized, so that no component weighs more than 75 lbs. One may can now move all the equipment necessary to pull up to 150,000 pounds (75 tons), in one average sized pick-up truck and hand carry it to remote areas normally inaccessible to the larger prior art equipment. The present invention has particular applications in the vast 4Δ diameter home lateral pipe field, which has, up to now been relatively untouched by the trenchless method of pipe replacement.
These and other features and advantages of the present invention will be well understood by those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment.
IN THE DRAWINGS
A mole pulling cable 70 is passed from the second end of the pipe 36, through the pipe 14 to a pinned engagement with the nose 48 of the mole 40. The cable 70 is utilized to pull the mole 40 through the pipe 14, parting and enlarging the pipe 14 as it is pulled therethrough. The replacement pipe 60 is pulled behind the mole 40, such that when the mole 40 has been pulled entirely through the pipe 14, the replacement pipe 60 will reside in place within the parted, expanded pipe 14 to functionally replace it.
A light weight cable pulling system, generally designated 80, is disposed within the second hole 32 proximate the second end 36 of the pipe 14. The preferred cable pulling system 80 includes a cable pulling frame member 84 having leg members 88 and a rotatable cable pulley 92 mounted thereto. A frame bracing reaction plate 96 is positioned against the side wall 100 of the hole 32 to provide a strong, firm surface for reactive cable pulling forces, as described herebelow. The reaction plate 96 is formed with a cable passage slot 104 (not shown in
The cable pulling device 120 is removably mounted to a generally cylindrical, slotted mounting socket or annulus 124 that is fixedly engaged to the frame 84. The cable pulling device 20 is preferably a hydraulic device which is operated utilizing a portable hydraulic pump 128 having hydraulic lines 132 leading therefrom to the cable pulling device 120. The cable pulling device 120 includes a cable pulling collet which releasably engages the cable for repeatable short pulling strokes. End portions of the cable 70 may be disposed in a coil 140 upon the ground surface 20.
It is therefore to be understood that an operator 150, having engaged the cable 70 to the mole 40, will pass the cable through the plate slot 104, around the pulley 92 into the slotted annulus 124 and into operative engagement within the cable puller 120 that is mounted in the socket 124. Thereafter, the operator 150 will activate the pump 128 and then activate the cable puller 120 to complete a first cable pulling stroke of perhaps 3 to 6 inches depending upon the travel of the hydraulic pulling device 120, as is discussed in greater detail herebelow. Repeated pulling strokes of the puller 120 ultimately pulls the mole 40 entirely through the pipe 14, until the mole 40 protrudes past the second end 36 of the pipe 14, whereupon the replacement pipe 60 has been pulled entirely through the parted, expanded pipe 14, in operational replacement thereof. The mole 40 is then disengaged from the replacement pipe 60. The cable pulling system 80 is then removed from the hole 32, appropriate pipe fixturing and jointing is accomplished at both ends of the replacement pipe, and the holes 24 and 32 can then be refilled.
It is therefore to be understood that the modular, light weight, pipe replacement system of the present invention allows a single worker to easily take all steps necessary to accomplish the replacement of a length of buried, pre-existing pipe. The various components of the system, the mole 40, the replacement pipe 60, the cable 70, the plate 96, the frame 92, the cable pulling device 120 and the pump 128 are all compact, light weight components that can be easily transported in a light duty pickup truck, and hand carried to, placed and assembled into the pulling hole by one man.
A first preferred mole of the present invention is depicted in
The pipe parting blades 56 are preferably disposed within a blade holding slot 184 formed in the tapered body 44 and cylindrical section 140 of the mole 40, and blade retaining pins 188 are disposed in retaining pin bores formed through the tapered portion 44 and the inner portions of the blades 56. The blades 56 are preferably formed of a hardened steel and are sharpened on the outer edge 180 to facilitate the pipe parting function of the blades 56.
The pipe scoring wheels 52 are preferably engaged in a scoring wheel holding member that is disposed within a scoring wheel slot 192 cut into the cylindrical portion 140 of the mole 40, and retaining pins 196 which project through retaining pin bores are utilized to hold the scoring wheel mechanisms in place. It is therefore to be understood that both the scoring wheels 52 and the blades 56 are removably engagable with the mole 40, such that they can be easily replaced when it is necessary to do so.
An alternative mole 220 is depicted in
A rearward portion 260 of the mole 220 includes a rearwardly extending replacement pipe engagement shoulder 264 and a pipe engagement sleeve 268, which together cooperate with pipe retaining screws 272 to hold a leading edge of a section of replacement pipe 278. A generally tapered impact driver bore 282 is preferably formed in the rearward end 260 of the mole 220 to provide a mating engagement with a tapered nose portion of an impact driver (not shown), as has been described hereabove with regard to mole 40, depicted in
The cable pulling frame 84 as depicted in
The frame bracing reaction plate 96 of the present invention is depicted in
It is to be understood that a significant feature of the frame member 84 is that a mole-attached cable 70 can be wrapped around the pulley 92, such that the interior portion 440 of the cable 70 projects between the legs 88 of the frame 84 and the outer end portion 444 of the cable 70 projects upwardly through the annulus 124 for engagement to a cable pulling device 120. Other and different frame construction configurations can readily be developed which provide the strength and stability of the frame member 84, and such alternative frame members are described hereinbelow.
A cable pulling device that is suitable for use in the present invention is depicted in a side elevational view in
A plurality of cable pulling collets 560 are removably engaged within the cable passage slot 550 of the forward end fixture 528. As depicted in
It is therefore to be understood that when hydraulic pressure is applied to the two piston members 510, that the outer housing portions 512 of the pistons 510 will move laterally rearwardly 580 relative to the piston rods 524 and the front end block 536. It is also to be realized that when the nose piece 540 of the cable pulling device 120 is mounted in the annulus 124 of the frame 84, that the front end block 536 will remain stationary while the forward end fixture 528 and the two piston outer housings 512 will move rearwardly. Additionally, it is to be understood that the collet members 560 are disposed within the movable forward end fixture 528, and that when the collets 560 move rearwardly relative to the cable 70, that the saw-tooth ridges 568 of the collets 560 will grab the outer surface of the cable 70 and pull it rearwardly. Finally, after the piston housings 512 have traveled rearwardly to the extent of a piston stroke, the housings 512 will return to the forward position and, significantly, the collet ridges 568 will release their hold upon the cable and slide forwardly along the surface of the cable 70. Thus, with each repeatable, rearward cable pulling stroke of perhaps three to six inches, depending upon the piston travel 580 of the cable pulling device 120, the collet ridges 568 will pull the cable 70 rearwardly. Thereafter, upon the return stroke of the cable pulling device 120, the cable 70 will remain stationary while the collets 560 slide along its outer surface. Thus, each cable pulling stroke will pull the cable rearwardly, until, ultimately, the cable with its attached pipe parting mole will be pulled entirely through the pipe 14.
A detailed depiction of the mounting of the cable puller nose piece 540 within the annulus 124 is provided in
As has been described hereinabove, the preferred method for installing the various components of the present invention upon a cable 70 is the side wise insertion of the cable 70 through the mounting slots 430 and 544 of the annulus 124 and nose piece 540 respectively. As depicted in
A single reaction plate mounting pin 682 is formed on the plate 620 to facilitate the mounting of the frame 600 with a mating bore (such as mounting pin bores 439) formed in a reaction plate, to which the frame 600 is removably engaged in a manner described hereinabove with regard to frame 84 and reaction plate 96. To further facilitate the engagement of the plate 620 with a reaction plate 96, a generally cylindrical cable guide member 684 is engaged within the slot 624. The guide member is also formed with a slotted cable passage bore 686 to permit the sideways insertion of the cable 70 therewithin. The guide member 684 is preferably formed with a smaller diameter portion 688 for mating insertion within the slot 624 of the plate 620, and a larger, outer diameter portion 690 for mating insertion within the cable mounting slot 104 of a reaction plate 96. In the preferred embodiment, the guide 684 is preferably formed from aluminum to provide a soft guide surface for interaction with the outer surface of the cable 70.
As compared with the four-legged cable pulling frame depicted in
Still another cable pulling frame 700 of the present invention is depicted in
Frame 700 is generally easier to fabricate than frame 600, although its overall dimensions are quite similar. Frame 700 generally consists of fewer components than frame 600 and is easier to assemble, whether by welding or the use of threaded bolts. It is to be understood that the frame 700, like frame 600 and frame 84, may be mounted upon a projecting end of an in-place cable 70, such that the cable 70 is mounted sideways into the cable insertion slots and wrapped around the pulley 740, as has been described in detail hereabove.
A further embodiment of the present invention is depicted in
In some working environments, a backward pulling force such as cable stretch or plastic pipe stretch may exist upon the cable 70 such that the cable may be pulled backwardly into the pipe 14 between the pulling strokes of the cable pulling device 120. In such a situation, a retaining collet may be inserted within the bore 428 of the annulus 124. Such a retaining collet includes two or more collet members such as collet members 560, held within a slotted cylindrical member, and which collets have reverse sawtooth ridges that grip the cable upon its movement backwards within the annulus.
Upon consideration of the various preferred embodiments described in detail hereinabove, it is to be understood that a generalized description of the present invention includes a mole, a cable attachable to the mole for pulling it through a pipe, a cable pulling device that is engagable to the cable and a cable pulling device engagement means which functions to provide a reactive support for the cable pulling device. In various embodiments, the cable pulling device engagement means includes the reaction plate and an annulus type member for holding the cable pulling device and may further include the various mounting frames and their components depicted and described herein. Significant features of the mole of the present invention include a plurality of pipe scoring wheels wherein two such wheels may be located on one side of the mole for enhanced pipe scoring, and wherein pipe scoring wheels can be located at 180° opposite surfaces of the mole for enhanced pipe scoring and parting of the pipe along the opposing scored lines. The preferred cable pulling device of the present invention is a hydraulic bridge cable tensioning device that operates in a cyclic cable pulling manner, having repeatable short pulling strokes. The cable is sideways mountable within the cable pulling device for ease of mounting and assembly. The cable pulling frames components and annulus are formed with cable mounting slots, such that these components may also be sideways mounted upon the cable for ease of assembly of the device.
A further mole design 900 is depicted in
As depicted in
A single blade 980 may be engaged within a blade holding slot 984 to project from the side of the tapered body portion 908. Significantly, the frontward edge 988 of the blade 980 is disposed rearwardly of the pipe fracturing region 916, such that the blade 980 is not utilized in the pipe fracturing activity of the mole 900. The blade 980 is utilized where the mole 900 encounters pipe engagement fixtures such as the pipe flanges 990 which include a flexible seal 994. Specifically, as depicted in
Still further alternative mole designs are depicted in
As can be seen with the help of
Returning to
A generally cylindrical mole engagement nut 1140 resides within the bores 1104 and 1116 of the mole. The nut 1140 includes a cylindrical outer portion 1144 that resides within bore 1104, an outwardly projecting shoulder 1148 that matingly engages shoulder 1112 of the mole, and an enlarged cylindrical portion 1152 that resides within the mole bore 1116. It is therefore to be understood that the nut 1140 is insertable into the mole through bore 1116 until the nut shoulder 1148 engages the mole shoulder 1112. A circumferential groove 1156 is formed in the outer surface of the cylindrical portion 1144 and a threaded screw 1160 is insertable in a threaded bore formed in the mole surface 1102 to hold the nut 1140 within the mole during the cable attachment process. The nut further includes a projecting hex nut end portion 1164 that is formed with flat hex nut surfaces, such that a wrench can be applied thereto to rotate the engagement nut 1140. The engagement nut 1140 further includes a cylindrical bore 1168 that is formed axially into the nut 1104. The bore 1168 terminates at an inwardly projecting shoulder 1172 which joins an inner threaded bore 1178.
A cable end fixture 1182 is engaged to the end of the pulling cable 70 by impact swaging 1184 an outer sleeve 1190 of the fixture 1182 onto the cable 70. The end 1192 of the fixture 1182 is formed with threads 1194 that threadably engage the threaded bore 1178 of the mole engagement nut 1140. The fixture 1182 is further formed with a radially projecting shoulder 1196 that engages the bore shoulder 1172 when the fixture 1182 is fully threadably engaged with the nut 1140.
It is therefore to be understood that the nut 1140 is first inserted into the mole bore 1116 and the screw 1160 is tightened such that it projects into the groove 1156 to hold the nut within the mole 1100. Significantly, the nut 1140 is rotatable within the mole bore 1116. Thereafter, the threaded cable end fixture 1182 is inserted into the bore 1168 and a wrench is then operatively engaged with the hex nut end portion 1164 of the nut 1140. The engagement nut 1140 is thereby rotated until the fixture 1182 is fully threadably engaged with the nut 1140. Thereafter, the pulling force upon the cable 70 will pull the nut 1140 and the engagement of the shoulders 1148 and 1112 will cause the mole to be pulled with the cable. The mole and cable are rotatable with respect to each other.
An alternative method for the attachment of replacement pipe to the rearward end of a mole is depicted in
A replacement pipe engagement sleeve 1220 comprises a generally cylindrical member having cylindrical sidewalls 1224 that are at least as thick as the sidewalls of the replacement pipe 60. The sleeve 1220 further includes a radially, inwardly projecting wall portion 1228 having a bore 1232 formed therethrough, such that the threaded sleeve engagement member 1216 projects through the bore 1232 when the sleeve 1220 is mounted to the rearward end 1212 of the mole 1200. A large threaded nut 1240 is threadably engaged upon the threads of the sleeve engagement member 1216 to frictionally engage the inwardly projecting wall 1228, such that the threadable tightening of the nut 1240 will cause the sleeve 1220 to be engaged to the mole 1200. The end 1250 of the replacement pipe 60 is thermofusion bonded 1254 to the wall 1224 of the sleeve 1220 after the nut 1240 has been threadably tightened to engage the sleeve to the mole. It is therefore to be understood that the replacement pipe 60 is engaged to the sleeve 1200 utilizing a thermofusion bond 1254 and the sleeve 1200 is threadably engaged to the mole 1200.
An improved PTR cable pulling device 1400 is depicted in
As was previously described with regard to cable puller 120, and with reference to
The front collets 1408 are thus provided to prevent the cable from returning to its unstretched position. Specifically, after a cable pulling stroke, and assuming that there is some cable stretching within the cable, upon release of the rearward collets 560, the cable will tend to move towards its unstretched position which would be leftward in
Where large pulling forces are required it may be necessary to attach two cables to a single mole and utilize two cable pulling devices, such that each cable pulling device is operating on one of the two cables. To effectively accomplish this, a pulling frame that accommodates two cables and two pulling devices is required. Such a pulling frame is depicted in
The significant advantages of the present invention are its relatively small, light weight components which allow a single operator to transport, install and operate the device for trenchless replacement of underground pipe. The larger pulling force generated by the PTR cable pulling device allows it to pull the mole through pipe of varying diameters and composed of virtually any pipe material, whether it be fracturable (such as cast iron or ceramic) or malleable (such as steel). The relatively low cost of the components permit individual contractors and small companies to effectively compete in a marketplace that heretofore has been reserved for large companies having the manpower and resources to purchase and transport the relatively large and expensive components that heretofore have been necessary to conduct the trenchless replacement of underground pipe.
While the present invention has been shown and described with regard to its preferred embodiments, it will be understood by those skilled in the art that alterations and modifications in form and detail may be made therein without departing from the true spirit and scope of the invention. It is therefore intended that the following claims cover all such alterations and modifications that encompass the true spirit and scope of the invention.
Claims
1. A device for the trenchless replacement of in-situ pipe, comprising:
- a mole;
- a length of cable, said cable being engagable to said mole;
- a cable pulling device being releasably engagable to said cable;
- a cable pulling device mounting frame being releasably engagable to said cable pulling device; and wherein said cable pulling device is a post tensioning ram (PTR).
2. A device as described in claim 1 wherein said cable pulling device includes at least one pair of cable engaging collets that function to engage said cable on a said pulling stroke and to release said cable on a said recovery stroke; and wherein-at least one further pair of collets is provided that function to engage said cable on said recovery stroke and release said cable on said pulling stroke.
6. A device as described in claim 2 wherein said further pair of collets is engaged within said cable pulling device.
7. A device as described in claim 6 wherein said cable pulling device is formed with a slotted cable insertion means for the sideways insertion of said cable within said cable pulling device.
14. A device for the trenchless replacement of in-situ pipe, comprising:
- a mole;
- a length of cable, said cable being engagable to said mole;
- a cable pulling device;
- a cable pulling device mounting frame being releasably engagable to said cable pulling device wherein said cable pulling device mounting frame includes an annulus member including a cable passage bore formed therethrough and a cable insertion slot formed through portions of said annulus member for the sideways insertion of said cable within said cable passage bore of said annulus member.
15. A device as described in claim 14 wherein said annulus member includes a cable pulling device holding means for releasably holding a portion of said cable pulling device therewithin.
16. A device as described in claim 14 wherein said cable pulling device mounting frame includes a reaction plate having an enlarged surface for disbursing a reaction force against a cable pulling force generated by said cable pulling device.
17. A device as described in claim 16 wherein said annulus member is mountable in relation to said reaction plate such that said reaction plate disburses cable pulling forces exerted on said annulus by said cable pulling device.
26. A device for the trenchless replacement of in-situ pipe, comprising:
- a mole;
- a length of cable, said cable being engagable to said mole;
- a cable pulling device including a cable engagement mechanism and a cable pulling device engagement means functioning to provide a mounting structure for said cable pulling device;
- said cable pulling device engagement means further including a reaction plate having an enlarged surface for disbursing a reaction force against a cable pulling force generated by said cable pulling device, and
- a cable pulling frame, said cable pulling frame being mountable to said reaction plate and said cable pulling device being mountable to said cable pulling frame.
30. A mole for use in the trenchless replacement of in-situ pipe, comprising, a nose portion being engagable to a cable, a tapered body portion and a replacement pipe engagement portion, said mole further including at least one blade, said tapered body portion acting to expand said in-situ pipe for the replacement thereof with a length of replacement pipe, and said blade acting to cut pipe engagement devices encountered by said mole after said pipe has been expanded by said tapered body portion.
33. A mole as described in claim 31 wherein a threaded bore is formed within said mole, and wherein a mole engagement fixture is fixedly engaged to an end of said cable, said fixture including a threaded end portion that is threadably engagable with said threaded bore.
34. A mole as described in claim 34 wherein said fixture further includes a hex nut portion integrally formed therewith and provided for the tightening of said threaded portion within said threaded bore.
36. A cable pulling device engagement frame comprising:
- an annulus member including a cable passage bore formed therethrough and a cable insertion slot formed through portions of said annulus member for the sideways insertion of a cable within said cable passage bore of said annulus member;
- a reaction plate having an enlarged surface for disbursing a reaction force against a cable pulling force generated through said annulus member.
37. A frame as described in claim 36 wherein said frame includes two cable pulling device engagement devices, such that two cable pulling devices can operationally function with said frame to pull two cables simultaneously.
38. A device as described in claim 37 wherein two annulus members function as said engagement devices to engage said two cable pulling devices.
39. A device as described in claim 38 wherein the two annulus members are angularly disposed relative to each other, such that two cable pulling devices are operationally engaged therewith.
40. A method for the trenchless replacement of in-situ pipe, comprising the steps of:
- exposing a first end of said pipe;
- exposing a second end of said pipe;
- disposing a pulling cable through said pipe between said first end and said second end;
- engaging a mole to said cable at said first end;
- engaging a cable pulling device to said cable at said second end; and
- installing a reaction plate at said second end after said cable is disposed through said pipe, and
- pulling said mole through said pipe utilizing said cable pulling device.
41. A method as described in claim 40 wherein said second end is exposed within an excavated hole, and wherein a reaction plate is disposed against a sidewall of said hole.
42. A method as described in claim 41, further including the installation of a cable pulling device engagement frame between said reaction plate and said cable pulling device after said cable is disposed through said pipe.
43. A method as described in claim 42 wherein said frame includes a pulley for changing the direction of said cable.
44. A method as described in claim 43 wherein said cable pulling device is disposed within said hole.
45. A method as described in claim 43 wherein said frame and said cable pulling device are disposed within said hole.
46. A method as described in claim 40, including the further steps of:
- engaging said cable with a first pair of collets on a cable pulling stroke of said cable pulling device, and
- engaging said cable with a second pair of collets on a recovery stroke of said cable pulling device.
47. A method as described in claim 40 wherein said cable pulling device is a post tensioning ram (PTR).
Type: Application
Filed: Sep 17, 2004
Publication Date: Feb 24, 2005
Inventors: Robert Carter (San Francisco, CA), Robert Carter (Oakland, CA)
Application Number: 10/944,089