GB2403994A

GB2403994A - Pipe renewing device having an adjustable push and pull unit

Info

Publication number: GB2403994A
Application number: GB0318700A
Authority: GB
Inventors: Dietmar Jenne
Original assignee: Terra AG fuer Tiefbautechnik
Current assignee: Terra AG fuer Tiefbautechnik
Priority date: 2003-07-16
Filing date: 2003-08-08
Publication date: 2005-01-19
Anticipated expiration: 2023-08-08
Also published as: DE10332328B3; GB2403994B; GB0318700D0; CH697170A5

Abstract

A device for replacing underground pipes comprising a frame 10 insertable into a first working pit intersecting the pipe and also comprising a push/pull unit 18 for pulling a tension element through the ground into the first working pit, the tension element being connected to a tool for destroying the old pipe and/or to an expansion head together with a new pipe portion starting from a second working pit, the push/pull unit 18 in the frame 10 is adjustable parallel to the direction of pulling A. Preferably the push/pull unit 18 includes a cylinder 20 and a gripper 22.

Description

A device for renewing underground supply pipes The invention relates to a

device for replacing underground supply pipes or for laying said pipes, comprising a frame insertable into a first working pit intersecting the pipe and also comprising a push/pull unit for pulling a tension element through the ground into the first working pit, the tension element being connected to a tool for destroying the old pipe and/or to an expansion head together with a new pipe portion starting from a second working pit.

Devices of the said kind are already known and are used for renewing old water or sewer pipes and for laying new pipes. In conventional installations of the kind in question, the frame initially adjoins the wall of the working pit through which the tension element extends. Some space must be provided in the working pit at the rear of the frame opposite the wall, e.g. in order to attach or remove the individual portions of a tension linkage. As soon as the splitting tool, the expansion cone and the new pipe for drawing through the earth are brought to the frame, in the conventional devices the frame and the push-pull unit must be moved about 1 to 1.5 metres back from the retaining wall, after which the frame must be shored up in front. This is done either with four struts extendable from the frame or with interposed struts or by means of a suitably long additional box positioned between the frame and the end wall of the working pit. The splitting tool, the expansion cone and the new pipe can then be pulled into the space - 1 to 1.5 metres - between the frame and the end wall of the pit.

This is laborious and, in view of the required high tensile forces of up to 60 t or more, is dangerous to the operators since the position of the device is unstable after being moved back.

The object of the invention is to construct a device according to the preamble which avoid the said disadvantages and enables the new pipe to be pulled conveniently and safely into the working pit.

To this end, according to the invention, the push/pull unit in the frame is adjustable parallel to the direction of pulling. As soon, in the device according to the invention, the splitting tool, the expansion cone and the new pipe have reached the frame or the end wall of the pit, the push/pull unit is moved back inside the frame so that the tools and the appropriate portion of the new pipe can be pulled into the pit and the frame. The frame retains its stable position. It eliminates the previously required labour of positioning and shoring up the device in the working pit.

In known manner the push/pull unit has at least one pressure-medium actuated working cylinder and a gripper for gripping the tension element and adjustable by the working cylinder parallel to the direction of pulling. The tension member can e.g. be a tension linkage, chain or cable made up of individual parts.

The push-pull unit can be fastened to the frame by mechanical locking means such as cotter pins or the like or by releasable pressure-actuated locking means. To help the operators to adjust the push- pull unit in the frame, a device can be provided for adjusting the push- pull unit relative to the frame.

In a particularly advantageous solution, the adjusting device is itself the working cylinder of the push-pull unit. If the working cylinder and the gripper are alternately and releasably connected to the frame, the push-pull device can be adjusted step by step by actuating the working cylinder. The gripper can also be fastened to the tension linkage while the working cylinder is uncoupled from the frame and still guided.

If the push/pull device has a single working cylinder, advantageously the working cylinder and the piston rod thereof bearing the gripper have an axial duct for admitting the tension element.

When a tension linkage is used, advantageously the linkage, pulled in on one side of the frame, can be pushed by the frame and the push/pull unit in the opposite direction into a pipe portion. If for example the first working pit is dug in the middle between two second working pits, two pipe portions can be replaced or laid, starting from the first pit in the middle, without having to dismantle the tension linkage in the meantime. Advantageously in this case the working cylinder is a double-acting cylinder with two piston rods extending from it from opposite sides and the gripper can be optionally connected to one or the other of the two piston rods. In an alternative arrangement, of course, the push/pull unit can be rotated through 180 if necessary for working in the opposite direction.

Preferably the gripper is mechanical or in the form of a clamping device actuated by a pressure fluid.

Optionally the clamping device is an automatic clamping device which clamps the tension element in one working direction and is movable freely relative to the tension element in the opposite direction.

In another advantageous arrangement, the working direction of the clamping device is reversible.

Alternatively the gripper can be designed for positively coupling to a suitably shaped pulling element.

Advantageously the gripper is prevented from rotating around the axis of the working cylinder.

This prevents screwed-together portions of the tension linkage from accidentally coming apart.

Rotation can be prevented e.g. by guiding the gripper on the frame as explained hereinafter with reference to an exemplified embodiment.

Preferably the frame has a rectangular base surface and at least two side walls extending parallel to the pulling direction and constructed as retaining walls for the working pit. There is thus no need to timber the working pit separately. Advantageously also, at least the frame wall facing the end wall of the working pit is designed as a blocking plate for preventing the old pipe for fracturing by the splitting tool and the expansion head from being pulled into the working pit during the replacement.

Since the frame needs to have a free space for adjusting the push/pull unit, the space can be used for a magazine for parts of the tension linkage.

The linkage magazine is taken out of the frame before adjusting the push/pull unit. The linkage magazine has a suitable passage or duct for pushing the tension linkage through the frame when necessary.

Preferably the splitting tool is equipped with at least three static cutting plates disposed around an axial central member. By this means the old pipe for replacement is cut or broken into portions sufficiently small to be pushed relatively easily into the ground around the pipe so as not to damage the new pipe when pulled in. Of course other splitting tools can be used, such as roller cutters disposed in line.

Other features and advantages of the invention will

be clear from the following description, which

explains the invention with reference to exemplified embodiments in conjunction with the drawings, in which: Figs. 1 to 3 are partially diagrammatic isometric views of a first embodiment of the device according to the invention with the push/pull unit in different working positions; Fig. 4 shows a variant embodiment of the device according to the invention wherein the side walls of the frame are increased in height in order to timber the pit; Figs. 5 and 6 are partly diagrammatic isometric views of a second embodiment of the device according to the invention with the push/pull unit in different working positions; Figs. 7 to 9 are diagrammatic plan views of a clamping device, explaining the operation thereof; Fig. 10 is a partly diagrammatic isometric view of the splitting tool for breaking up a pipe for replacement, together with the expansion head and a part of a new pipe for pulling in; Fig. 11 is an exploded view of the arrangement shown in Fig. 10, and Figs. 12 to 14 are diagrams explaining the operation of the device according to the invention when replacing old pipes.

Fig. 1 shows a device comprising a frame (general reference 10) with two parallel side walls 12 and 14 connected by one or more transverse struts 16 (only one shown here). A push/pull unit (general reference 18) is disposed in the frame 10 and comprises a working cylinder 20 and a gripper 22 connected to the free end of a piston rod 24 of the The push/pull unit 18 is adjustable relative to the frame 10 in the direction of the double arrow A in Fig. 1, which also shows the operating direction of the working cylinder 20. The push/pull unit is fixed by cotter pins 26 which extend through bores 28 in rails 30 on the inside of the side walls 12, 14 and also extend through bores (not shown) formed in a frame 32 which receives and surrounds the working cylinder 20. By means of the cotter pins 26, the working cylinder 20 can be fixed inside the frame 10 in a front position shown in Fig. 1 and in a rear position shown in Fig. 3.

The piston (not shown) of the working cylinder 20 is connected at both ends to a piston rod 24 formed with an axial bore 34 through which a tension linkage 36 (Figs. 12 to 14) can extend. A control panel 40 is fastened to the side wall 14 via a support 38. A lever 42 on the panel 40 is for controlling the supply of pressure medium to the working cylinder 20, wherein the pressure-medium connections 44 are connectable by lines 46 to the control panel 40 and, via the control panel, to a pressure- medium source or tank.

Eyelets 48 for lifting the entire device by a crane are fastened to the top edge of the frame 10.

The gripper has two laterally projecting arms 47. A roller 49 is mounted on the free end of each arm and guided on the underside of a rail 30, thus preventing the gripper from rotating round the axis of the working cylinder.

The gripper 22 is an automatic clamping device which clamps a tension linkage when set in one direction but is freely movable relative to the tension linkage when set in the opposite direction. The working direction, i.e. the clamping direction of the clamping device, is reversible. The operation of the clamping device 22 will be explained with reference to Figs. 7 to 9.

In Fig. 7 the clamping device 22 has a casing 50 on which two clamping jaws 52 are mounted, each pivotable around a journal 54. The clamping jaws 52 each have a semicircular cross-section groove, the base of which is indicated by a broken line 53. By means of the groove, the jaws 52 can clamp a portion 56 over a part of its periphery extending between the jaws. The centre of curvature M of the base of the groove 53 is at a greater distance from the linkage for clamping than the axis of the journal 54. The difference shown in Fig. 7 need not correspond to the actual dimensions. The centre M of the circular groove base 53, i.e. the surface of the clamping jaws, is thus off the axial centre point of the journal 54.

The clamping jaws 52, at their end remote from the linkage part 56, each have a journal 58 which engages a spring 60, the other end of which is connected to the free end of a rocking lever 62 mounted on the casing for pivoting around an axis 64.

Figs. 7 to 9 show the rocking lever 62 in three different positions, i.e. pivoted to the right in Fig. 7, in a middle position in Fig. 8 and pivoted to the left in Fig. 9. Firstly the clamping jaws 52, in the position shown in Fig. 7, are slightly pressed by the springs 60 against the linkage part 56. When the chain-line piston rod 24 is driven into the chain-line working cylinder 20 in Fig. 7, i.e. the clamping device 22 moves to the right in Fig. 7, the two clamping jaws 52, owing to the friction between them and the linkage part 56, are swung in the direction for prestressing the respective tension springs, with the result that the clamping surfaces (or groove base) of the jaws 52 try to approach one another and thus clamp the linkage part 56. The stronger the pull of the working cylinder 20, the greater the clamping force.

At tensile forces of 60 t, the clamping forces are over 300 t. If the piston rod 24 in Fig. 7 moves to the left out of the working cylinder 20, the clamping jaws 52 loosen and return nearly into the neutral position. During this process a cotter pin 66 prevents the two clamping jaws 52 swinging over the neutral position in the opposite direction, since otherwise they would clamp the linkage on the other side.

The journal can occupy three different positions.

In the position in Fig. 7 it is inserted into a bore 63 in the casing (Fig. 8). In the neutral position in Fig. 8 it is inserted into a central bore (not shown) and in the position in Fig. 9 it is inserted into a right-hand bore 65 (Fig. 8). The position shown in Fig. 7 corresponds to a pushing position.

Fig. 8 shows the rocking lever 62 in a neutral central position in which the clamping device 22 and the linkage part 56 can move freely relative to one another. The clamping jaws 52 are prevented from pivoting by the cotter pin 66. Fig. 9 shows the rocking lever 62 and clamping jaws 52 in the opposite pivoted position to the arrangement in Fig. 7. Clamping occurs in that case when the clamping device 22 is moved to the left in Fig. 9, i.e. the piston rod 24 is extended out of the working piston (the pull position).

Figs. 5 and 6 show another embodiment of the device according to the invention. Like or equivalent parts are as before given the same reference numbers. The device in Figs. 5 and 6 differs from the embodiment in Figs. 1 to 3 in that the frame 10 is longer, thus providing space for a linkage magazine 68 for holding parts of a tension linkage.

The linkage magazine has eyelets 70 so that it can be lifted from the frame 10 by a crane when the space is needed for adjusting the push/pull unit 18 (Fig. 6). A seat 72 for an operator is also disposed on the linkage magazine.

Fig. 4 shows a variant of the exemplified embodiments shown in Figs. 1 - 3 and 5, 6 wherein the side walls 12 and 14, the end wall 74 and the opposite transverse wall 76 are made higher and constructed so as to serve as retaining walls for the working pit into which the device according to the invention is inserted. The end wall 74 is specially reinforced and in the form of a blocking plate for preventing an old pipe, when broken up by the splitting tool, from being pushed into the frame 10. The end wall 74 has a slot 78 at the bottom for inserting the tension linkage.

The end wall 74 is removable. As soon as the splitting tool and the new pipe have reached the working pit, the end wall 74 is removed and uncovers a large opening in the frame 10 for pulling the splitting tool and the new pipe into the frame 10.

Figs. 10 and 11 show the tools which are drawn through the earth by the device according to the invention. The drawings show a splitting wedge 80 comprising a central tubular or rod-shaped member 82 and three cutting plates 84 disposed at equal angles around the body 82 and comprising a stepped cutting edge 86 in known manner for breaking open cast pipes and connecting sleeves thereof. The splitting wedge is connected at one end to a tension linkage 36 and at the other end via a linkage portion 88 to a conical expansion head 90 whereby the fragments of an old pipe produced by the splitting wedge 80 are pressed into the surrounding earth and space is made for putting in a new pipe 92 which can be connected to the cylindrical rear portion 94 of the expansion head 90 by lugs 96 and bolts 98.

Figs. 12 to 14 illustrate the operation of the device according to the invention when an old pipe is replaced. Two working pits 100, 102 are made at the two ends of a pipe portion for replacement. An additional working pit 104 intersecting the pipe 106 for replacement is made in the middle between the two pits 100 and 102. The device shown in Figs. 5 and 6 is inserted into the working pit 104.

In Fig. 12, a tension linkage 36 is first pushed by the push/pull unit 18 to the working pit 100 through the left portion of the pipe 106 for replacement.

The splitting wedge 80, the expansion head 90 and the new pipe 102 for pulling through are then connected to the free end of the tension linkage 36.

As shown in Fig. 13, the tension linkage 36 and the parts attached thereto are then pulled by the push/pull unit 18 towards the middle pit 104, when the old pipe is broken up by the splitting wedge 80.

The parts of the old pipe are pressed by the expansion head into the surrounding earth, making space for pulling in the new pipe 92. After being withdrawn, the tension linkage 36 is not dismantled but is moved forward to the same extent in the direction towards the end pit 102 into the right- hand portion of the pipe 106 for renewal. As before the splitting wedge 80, the expansion head 90 and the pipe 92 for pulling in are suspended from the free end of the tension linkage as previously described. The tension linkage 36 is pulled in by the push/pull unit 18, after which the second or right-hand portion of the pipe for renewal is ready in position. The pipes are then pulled into the frame or pit 104 until they can be connected after removing the device according to the invention.

Claims

C L A I M S

1. A device for replacing underground supply pipes or for laying said pipes, comprising a frame insertable into a first working pit intersecting the pipe and also comprising a push/pull unit for pulling a tension element through the ground into the first working pit, the tension element being connected to a tool for destroying the old pipe and/or to an expansion head, together with a new pipe portion starting from a second working pit, characterized in that the push/pull unit in the frame is adjustable parallel to the direction of pulling.

2. A device according to claim 1, characterized in that the push/pull unit has at least one pressure- medium actuated working cylinder and a gripper for gripping the tension element and adjustable by the working cylinder parallel to the direction of pulling.

3. A device according to claim 1 or 2, characterized in that the push/pull unit can be fastened to the frame by mechanical or pressure- medium actuated releasable locking means.

4. A device according to any of claims 1 to 3, characterized in that it comprises an adjusting device for adjusting the push/pull unit relative to the frame.

5. A device according to claims 4 and 2, characterized in that the adjusting device is itself formed by the working cylinder of the push/pull unit.

6. A device according to any of claims 1 to 5, characterized in that the tension element is a linkage which can be assembled from a number of parts.

7. A device according to claim 6, characterized in that the working cylinder and the piston rod thereof bearing the gripper have an axial duct for admitting the tension element.

8. A device according to any of claims 1 to 7, characterized in that the linkage, pulled in on one side of the frame, can be pushed by the frame and the push/pull unit in the opposite direction into a pipe portion.

9. A device according to claim 8, characterized in that the working cylinder is a double-acting cylinder with two piston rods extending from it from opposite sides and the gripper can be optionally connected to one or the other of the two piston rods.

10. A device according to any of claims 1 to 9, characterized in that the gripper is mechanical or in the form of a clamping device actuated by a pressure fluid.

11. A device according to claim 10, characterized in that the clamping device is an automatic clamping device which clamps the tension element in one working direction and is movable freely relative to the tension element in the opposite direction.

12. A device according to claim 11, characterized in that the working direction of the clamping device is reversible.

13. A device according to any of claims 1 to 8, characterized in that the gripper is adapted for positive engagement of the tension element.

14. A device according to any of claims 1 to 3, characterized in that the gripper is prevented from rotating around the axis of the working cylinder.

15. A device according to any of claims 1 to 14, characterized in that the frame has a rectangular base surface and at least two side walls extending parallel to the pulling direction and constructed as retaining walls for the working pit.

16. A device according to claim 15, characterized in that at least one of the walls of the frame extending at right angles to the pulling direction is a blocking plate for preventing the old pipe for replacement from moving in the pulling direction.

17. A device according to any of claims 1 to 16, characterized in that a magazine for linkage parts is disposed in the frame.

18. A device according to any of claims 1 to 17, characterized in that the splitting tool comprises at least three static cutting plates disposed around an axial central member.

19. A device according to any of claims 1 to 17, characterized in that the gripping tool has roller cutters disposed one behind the other.

20. A device for replacing underground supply pipes or for laying said pipes substantially as hereinbefore described with reference to and as shown in Figures 1 to 3, Figure 4, Figures 5 and 6, or Figures 10 to 14 of the accompanying drawings.