JPH0150163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates generally to U.S. Patent Application No. 196,847, filed October 14, 1980, hereinafter referred to as
Reichman).
For more information regarding cable tracking devices particularly suitable for use in replacing existing underground cables, see U.S. Patent Application No. 3, filed Aug. 3, 1981.
No. 289211 (hereinafter referred to as Reichman)
This invention relates to an improvement in one of the cable following devices disclosed in .

mentioned above and included here for reference
Reichman's patent application discloses techniques for replacing existing underground cables and special equipment for making this replacement. The device has a cable follower interconnected with the cable to be replaced for sliding movement along the cable. At the same time, a device is provided for softening around the cable, preferably by one or more fluid jets. Once the soil is soft, the cable can be easily pulled out of the ground and replaced with a new one. The Reichman application discloses a special cable following device that
Also, Reichman listed here for reference
The application discloses two additional devices.
The most preferred of these devices are especially
The main body is shown in FIGS. 6 to 9 of the Reichman application and is configured to be freely inserted and removed;
A pair of cable gripping mechanisms and a liquid-operated piston
It has a cylinder device. A housing is placed around the particular cable to be replaced, and two cable gripping mechanisms alternately grip the cable by sliding the removable body forward along the cable using a piston-cylinder arrangement. to do or release.

Each of the special cable following devices described in the above-mentioned Reichman et al. application is designed to move only in a forward direction along the associated cable. For example, in the preferred embodiment just described, at any time during a cable following procedure, one of the gripping mechanisms is in gripping engagement with the cable so that the entire cable following device is not pulled rearwardly along the cable. However, if, for example, the cable follower fails while moving forward along the cable, or if there is an obstacle in the forward path of movement of the device, the cable follower must be returned to its starting point. It has been found that there are cases where it is desirable or even necessary. at the same time,
It would be desirable to retain the general configuration of the preferred cable follower disclosed in FIGS. 6-9 of the Reichman application.

In view of the foregoing, one object of the present invention is an improved cable tracking device of the general type described in the above-referenced Reichman et al. patent application, comprising:
To provide a device that can be moved backwards along an associated cable.

Another object of the invention is that it can be moved forwardly along the associated cable in the same manner as the preferred cable following device described above and backwardly moved along the cable without the need for complex mechanisms. It is possible to provide a cable following device.

As will be appreciated from the following description, the cable following device disclosed herein has a main body and a device coupled to the main body and utilizing first and second cable gripping devices, the cable tracking device being disclosed herein has a main body and a device coupled to the main body and utilizing first and second cable gripping devices. The cable gripping devices of , as long as one of the gripping devices engages the cable.
The main body is moved in a forward direction along the cable, but the associated cables are alternately gripped in a manner that prevents the main body from moving in a rearward direction. Furthermore,
According to the invention, the cable following device disclosed herein has a device for releasing both gripping devices from the cable, so that its main body can be moved along the cable, for example by a dragnet. It can be moved backwards. In a preferred embodiment, the dragnet is used not only to pull the cable following device in a rearward direction along its associated cable, but also to initially disengage both cable gripping devices from the cable at the same time.

The improved cable gripping apparatus disclosed herein will be described in more detail below in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the accompanying drawings (in which like components are designated by like reference numerals in each figure), there is shown a cable follower or main body generally designated by the reference numeral 200. The device is shown as having an outermost support tube or first section 202 whose rear end is closed off by an aft flange 204 and an associated pilot spacer 206 . The forward end of support tube 202 supports a forward end cap structure 208, which is similar to any of the forward end cap structures forming part of the cable follower described in the Reichman et al. application. The particular embodiment illustrated, structure 208, is from Reichman
, and do not form part of the invention and are therefore merely generally indicated.

Continuing with the description of apparatus 200, a forward cable guide tube 226 is disposed within tube 202, the forward-most end of which is connected to forward end cap structure 20 in the illustrated embodiment.
It is integrally connected to 8. tube 202 and tube 22
6 are both arranged around a predetermined cable 227. For reasons explained below, cable guide tube 226 is located at the bottom end of tube 202 and has an opening 288 in the top sidewall of cable guide tube 226 slightly inward of structure 208.

Also, a second cable guide tube or second portion 230
is located within the support tube 202, axially in line with and immediately rearward of the tube 226, and with the cable 22
They are arranged around 7. However, tube 2
30 is supported within tube 202 for axial sliding movement into and out of tube 202 through the rear end of tube 202, ie, toward and away from the rear end of tube 226. To effect this movement of the tubes relative to the tubes 202, 226, the rear flange 2
04 includes an appropriately sized opening 232 and a guide bushing 234 around the opening in sliding engagement with the outer surface of the tube 230. Otherwise tube 230 will slide on the inside of tube 202. For reasons explained below, the slidable tube 230 has an opening 236 in its top sidewall at an intermediate point along its length, and a flange 238 is inserted into the sidewall immediately in front of this opening. and extends upward from this side wall.

In addition to the above-mentioned components, the cable following device 2
00 has a first cable gripping device 240 and a second cable gripping device 242. The cable gripping device 240 is somewhat L-shaped in shape as shown in the accompanying drawings and is arranged through the opening 228 in the cable engagement position shown in FIG. 2 and in the cable engagement position shown in FIGS. 1 and 3. It is mounted within the outermost tube 202 for rotation about an axis 244 between and out of engagement with the cable 227 . A pivot pin or other suitable device may be utilized to support the cable gripping device 240 so long as the cable gripping device is slidably movable with the outermost tube 202 and guide tube 226 in the manner described above. . The cable gripping device 242 has a similar shape and is coupled to the sliding tube 230, while at the same time holding the cable 227 in a position out of engagement with the cable 227 as shown in FIGS. 2 and 3. It is pivotally mounted about axis 248 as shown for movement between a cable engagement position within opening 236 and a position for engaging the cable.

The entire cable tracking device 200 also includes an outermost tube 202 and its associated cable guide tube 22.
6 along the cable, alternating with the tube 230, and a device 25 for sliding the cable progressively forward relative to the cable.
It has 4. For this purpose, the device 254
has a hydraulic cylinder arrangement 256 disposed within the outer tube 202. The hydraulic cylinder arrangement includes an outer cylinder 258 and a piston 260 that is movable in and out of the extended position and in the retracted position within the rear end of the cylinder. Two ports are provided on cylinder 258, a rear port 262 and a front port 264. mentioned above
As described in more detail in the Reichman patent application, the aft port is adapted to receive fluid under pressure from a suitable source, and the forward port is adapted to receive fluid under pressure in a similar manner. For reasons explained below, hydraulic fluid enters the cylinder 258 through its aft port 262.
When applied from the piston, the piston 260 moves forward relative to the cylinder while the cylinder is simultaneously pushed rearward relative to the piston. When fluid is directed to port 262, port 264 remains open to ambient pressure (ie, generally pressure free). This procedure is for port 26
2 to ambient pressure and simultaneously directing hydraulic fluid to the cylinder via port 264.
It will be the opposite.

As a result, the cylinder moves forward (in the right direction in the drawing, i.e. in the direction of the arrow shown in FIG. 1), and the piston moves backward (in the left direction in the drawing,
That is, it is pushed in the direction opposite to the arrow shown in FIG. It will be explained below how this alternating movement of piston and cylinder causes the entire device to slide forward in incremental steps along the cable. However, to allow this to occur, the front end of the cylinder is pivotally connected to the cable gripping device 240 by suitable pivoting means 278, and
Movement of the cylinder between the rearward and forward positions relative to 44 moves the entire gripping device 240 between the locked position shown in FIG. 2 and the unlocked position shown in FIG. In a similar manner, piston 260 is pivotally connected to cable gripping device 242 by suitable pivot means 282 near its rearmost end. The forwardmost end portion of rod clevis 288 is utilized to make this connection. The connection between piston 260 and cable gripping device 242 is such that forward and backward movement of the piston relative to axis 248 as described above causes the cable gripping device to be moved out of engagement with the cable as shown in FIG. , and the cable gripping position shown in FIG.

The overall cable follower 200, as previously described, is structurally and functionally similar to the embodiment shown in FIGS. 6-9 of the above-referenced Reichman patent application. As described in this Reichman application, the device moves in incremental steps along the cable from one end of the cable to the other. For purposes of illustration, cable gripping device 24
Assume that 0,242 is initially in the position shown in FIG. 2, with port 264 open to ambient pressure and hydraulic fluid applied to the cylinder from port 262. Under these conditions, the piston 260 is moved forward and the cylinder is biased rearward. The rearward biasing of cylinder 258 brings cable gripping device 240 into tight gripping engagement with cable 227 to secure tube 226 in place. at the same time,
Forward movement of piston 260 causes cable gripping device 242 to remain out of engagement with the cable. Furthermore, when the piston moves forward,
The piston pulls the cable gripping device 242 and the cable guide tube 230 forward with it. This movement continues until the forward-most end of tube 230 engages the rearmost end of tube 226. At the same time, the piston
Designed to be completely retracted into the cylinder. When this occurs, port 262 is open to ambient pressure and port 264 receives hydraulic fluid. This moves the piston rearwardly a small distance, i.e., in particular, a distance sufficient to pivot the cable gripping device 242 into fixed engagement with the cable. At the same time, the cylinder moves forward relative to the fixed piston, pivoting the cable gripping device 240 out of engagement with the cable. Thus, the entire cylinder can continue to move in the forward direction, thereby causing tube 202
and 226 forward in incremental steps against the fixed tube 230. This ultimately places the piston in an extended position relative to the cylinder and allows tube 226
A correspondingly large distance is created between the rear end and the front end of tube 230, respectively.

The procedure described above is repeated continuously. In other words, the cable gripping device 240 is in the cable gripping position and the piston moves forward into the cylinder from its extended position to its retracted position while the cable gripping device 242 disengages the cable, thereby causing the piston to move forward into the cylinder from its extended position to its retracted position. 230 is moved forward in incremental steps relative to the cable.

Thereafter, while the cable gripping device 242 is in the cable gripping position and the cable gripping position 240 is out of engagement with the cable, the cylinder 258
moves forward, thus causing tubes 202 and 226
Move forward in incremental steps. It is clear from this pattern that the cable gripping device does not engage the cable 227 during movement of the guide tube associated with it. However, at the same time it is equally clear that one of the cable gripping devices always engages the cable when the entire device is moved incrementally in the forward direction. As long as this is the case, it is not possible to move the device backwards, for example by seine netting or the like.

As will be seen below, the entire device 200 can be pulled rearwardly along the cable so that this can be done if it becomes desirable or necessary to do so.
Overall apparatus 200 provides a relatively simple technique for simultaneously disengaging cable gripping devices 240 and 242 from cable 227. To this extent, the overall device 200 differs from, and is an improvement over, the cable tracking device described in FIGS. 6-9 of the Reichman application.

To release both cable gripping devices 240 and 242 from cable 227, entire device 20 is removed.
0 has a rope 300 secured to the rear end of tube 230 by a suitable flange connection, generally designated 302. Furthermore, clevis 288 is
a rearwardly extending portion 304;
4 is adapted to engage spacer 206 in a manner described below. These are the only additional components forming part of apparatus 200 necessary to simultaneously release cable gripping devices 240 and 242 from cable 227 (see FIGS. 6-6 of the Reichman application), as will be seen below. (compared to the components in the embodiment of FIG. 9).

The cable gripping devices 240 and 242 are connected to the cable 2
To release from 27, it is necessary for the person wishing to do so to pull the rope 300 under appropriate tension as the cable follower moves forward in the normal manner. The operator should be aware that when the piston-cylinder unit completes its retraction stroke (during which period the front gripping device 240 is in the cable gripping position and the device 242 is in the disengaged position), both Begin to release the cable gripping device. After this cycle is finished, at the beginning of the next cycle (when the piston-cylinder unit expands), the operator moves the tube 230 in a backward direction (through the rope 300) at a faster rate than the piston-cylinder unit expands. start pulling). As a result, the rear gripping device no longer engages the cable during this cycle. At the same time, the tension applied to tube 230 by rope 300 is applied to cylinder 258
The gripping device 240 acts to prevent the gripping device 240 from coming off the cable 227 through the cable 227 . However, when the piston 260 reaches the end of its extension stroke (fully out of the cylinder), the rearmost end 304 of the rod clevis 288 engages the spacer 206 as shown in FIG. This causes the cylinder to move forward relative to the piston, and the cylinder pushes against the forward gripping device 240, causing the cable 22
Remove from 7. At this time, both gripping devices are in the cable release position as shown in FIG. 3, and the entire device can be pulled rearwardly along cable 227 by rope 300.

[Brief explanation of drawings]

FIG. 1 is a partially cut away longitudinal sectional view of the cable follower in a first operating position; 2 is a view similar to FIG. 1 in a second operating position of the cable follower; FIG. FIG. 3 is a view similar to FIGS. 1 and 2 in a third operating position of the cable follower; 200... cable following device, 202... tube,
204... Rear flange, 206... Pilot spacer, 208... Front end cap structure, 206
...Tube, 227...Cable, 226,230...
... Cable guide tube, 232 ... Opening, 234 ...
...Guide bushing, 236...Opening, 238...
...Flange, 240,242...Cable gripping device, 244,248...Axis, 258...Cylinder, 262,264...Port, 260,272
... Piston, 282 ... Pivoting means, 300
...rope, 288...rod clevis.

Claims (1)

[Scope of Claims] 1. A device for moving forward along the length of an existing cable, the main body having a first portion and a second portion interconnected to allow a fixed amount of sliding movement relative to each other. a main body; first cable gripping means and second cable gripping means respectively connected to a first portion and a second portion of the main body; each of the cable gripping means having a first position for gripping the cable; and a second position in which the cable is not gripped, and has means capable of moving in a predetermined manner, the first cable gripping means and the second cable gripping means alternately gripping the cable, and the first cable gripping means grips the cable alternately and further comprising a structure for sliding the first part and the second part relative to each other to move the main body in a forward direction along the cable; and rope means coupled to the main body, the rope means being adapted to move the main body forwardly along the cable. When the main body is pulled rearwardly by the rope means at a particular point in the predetermined movement of the capable means, both gripping means are held in the non-grasping position, and when the main body is continued to be pulled rearwardly by the rope means, the main body is A device characterized in that it cooperates with said structure to move rearwardly with rope means. 2. The structure has a piston-cylinder mechanism serving as a movable means, the piston-cylinder mechanism being moved in a predetermined manner by telescoping, and the piston-cylinder mechanism is arranged in a first cable-gripping means. and a second cable gripping means for alternately gripping the cable and for sliding the first and second parts of the main body relative to each other when the piston-cylinder mechanism extends and retracts in a predetermined manner. 2. The device according to claim 1, wherein the device is connected to one cable gripping means and a second cable gripping means.