CA1195516A - Cable gripping apparatus having forward and rearward movement capabilities - Google Patents
Cable gripping apparatus having forward and rearward movement capabilitiesInfo
- Publication number
- CA1195516A CA1195516A CA000434419A CA434419A CA1195516A CA 1195516 A CA1195516 A CA 1195516A CA 000434419 A CA000434419 A CA 000434419A CA 434419 A CA434419 A CA 434419A CA 1195516 A CA1195516 A CA 1195516A
- Authority
- CA
- Canada
- Prior art keywords
- cable
- piston
- cylinder
- gripping
- segment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G1/00—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
- H02G1/06—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for laying cables, e.g. laying apparatus on vehicle
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/18—Anchoring or feeding in the borehole
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/18—Drilling by liquid or gas jets, with or without entrained pellets
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/28—Enlarging drilled holes, e.g. by counterboring
Abstract
Abstract of the Disclosure:
An improved cable following apparatus especially suitable for use in replacing an existing underground cable is dis-closed herein. This apparatus utilizes a telescopically configured main body disposed around a cable in question and front and rear cable gripping mechanisms which alternatively grip the cable so as to cause the telescopic body to slide along the latter in a forward direction. The cable follow-ing apparatus also includes a technique for releasing both of the gripping mechanisms from the cable at the same time in order to be able to pull the entire apparatus rearwardly in the event it becomes necessary or desirable to do so.
An improved cable following apparatus especially suitable for use in replacing an existing underground cable is dis-closed herein. This apparatus utilizes a telescopically configured main body disposed around a cable in question and front and rear cable gripping mechanisms which alternatively grip the cable so as to cause the telescopic body to slide along the latter in a forward direction. The cable follow-ing apparatus also includes a technique for releasing both of the gripping mechanisms from the cable at the same time in order to be able to pull the entire apparatus rearwardly in the event it becomes necessary or desirable to do so.
Description
The present invention relates yenerally to a cable fol-lowing apparatus especially suitable for use in replacing an exis-ting underground cable as described in United States Patent No. 4,385,667 (hereinafter referred to as Reichman I) and more particularly to an improvement in one of the cable following appa-ratus disclosed in United States Patent ~o. 4,403,667 (hereinafter referred to as Reichman II).
The Reichman I patent application recited above specif-ically discloses a technique for replacing an existing underground cable and a specific apparatus for doing so. The apparatus includes a cable follower which is interconnected with the cable to be replaced for slidable movement along the latter. At the same time, means are provided for loosening the soil around the cable, preferably by means of one or more fluid jets. Once the soil is loosened, the cable can be easily pulled out of the ground and replaced with a new cable. A speciEic cable following arrangement is disclosed in the Reichman I application and two additional arrangements are disclosed in Reichman II. I'he most preferred one of these arrangements i5 described specifically ~n Figures 6-9 oE Reichman II and includes a telescopically conEigured main body, a pair of cable gripping mechanisms and a hydraulically actuated piston-cylinder device. The housing is disposed around the particular cable to be replaced and the piston-cylinder unit is used to cause the two cable gripping mechanisms to alternately grip and release the cable in a way s~
which causes the telescopic body to slide along the cable in a forward direction.
Each of the specific cable followers described in Reichman I and II recited above is designed to move along its associated cable in a forward direction only. For example, in the preferred embodiment described immediately above, at any time during its cable following procedurel one of the gripping mech-anisms remains in gripping engagement with its cable so that the overall cable following apparatus cannot be pu110d rearwardly along the cable. However, it has been found that there are times when it is desirable or even necessary to bring the cable following apparatus back to its starting point, for example if it malfunctions during its forward movement along the cable or if an unpenetrable obstruction lies in its forward path of movement. At the same time, it i6 desirable to retain the general configuration of the preferred cable ~ollowing apparatus disclosed in Figures 6-9 of Reichman II.
In view of the foregoing, it is one object of the pre-sent invention to provide an improved cable following apparatus of the general type described in the Reichman I and II patent appli-cations recited above but one which is capable of being moved rearwardly along an associated cable.
Another object of the present invention is to provide a cable following apparatus which moves in a forward direction along its associated cabLe in the same way as the preferred cable ~ol:Lowing apparatus recited above but which may be moved rear-..~, ,~ I
~s~
~ 3 --wardly along the cable without requiriny a complicated mechanismto accomp:Lish this.
According to one aspect of the invention there is pro-vided an apparatus for moving along the length oE an existing cable in a forward direction, comprising; a main body including first and second segments interconnected for limited slidable movement relative to one another; means for supporting said main body to said cable such that alternating slidable movement of said body segments in said forward direction causes said main body to slide forward along said cable, said supporting means including firs-t cable gripping means connected with said first bod~ segment and movable between a first position in engagement with said cable for preventing said first segment from sliding along said cable and a second position out of engagement with said cable and second cable gripping means connected with said second body segment and movable between a first position in engagement with said cable for preventing said second segment rom sliding along said cable and a second position out of engagement with said cable; means for causing said first and second body segments to slide alternately in the forward direct.ion, said slide causing means including means for maintaining said first gripping means in its cable engaging first position during sliding movement of said second segment and in its second position out of engagement with said cable during sliding movement of said first segment and, at the same time, for maintaining said second gripping means in its cable engaging first position during sliding movement of said first segment and its second position out of engagement with said cable during said sliding movemen-t of said second segment; and cable freeing means for placing both said first and second cable gripping means in their respective second positions out of engagement with said cable, at the same time, whereby said main body can be pulled rearwardly along said cable at a faster rate, said last mentioned means including rope means connected with one of said body seg-ments for pulling said main body in a rearward direction along said cable when said first and second cable gripping means are in their second positions at the same time, said slide causing means including a piston-cylinder mechanism including an outer cylinder and a piston disposed within said cylinder for movement between an extended position and a retracted position relative to said cylin-der whereby to cause the overall mechanism to expand and contract in length, means for causing said piston-cylinder mechanism to expand and contract in length in a controlled alternating fashion, and first and second means for respectively connecting said cylin-der to said first cable gripping means and said piston to said second cable gripping means such that during the expansion of said piston-cylinder mechanism, said first body segment is caused to slide forward relative to said cable while said second cable grip-ping means is maintained in its cable gripping position so as to prevent said second body segment from moving relative to said cable and such that contraction of said piston-cylinder mechanism causes saicl second body segment to slide forward relative to said cable while said first gripping means is maintained in the cable gripping position so as to prevent said firs-t body segment from moving relative to said cable, said cable freeing means including t~." `~
means for preven-ting said second cable gripping means from engaging said cable during the expansion of said piston-cylinder mechanism while at the same time maintaininy said first cable gripping means disengaged from said cable.
According to a second aspect of the invention there is provided an apparatus for moving along the length of an existing cable in a forward direction, comprising; main body means; first and second cable grippers connected with said main body means, each of said grippers being movable between one position for grip-ping said cable and a second non-gripping position; means for causing said grippers to al-ternately grip said cable in a way which causes said main body means to move in a forward direction along said cable, said last-mentioned means including a piston cylinder mechanism having an outer cylinder and a piston disposed within said cylinder for movement between an extended position and a retracted position relative to the cylinder whereby to cause the overall mechanism to expand and contract in length and means for causing the piston-cylinder mechanism to expand and contract in length in a controlled alternating fashion, said cylinder being connected with said first gripper and said piston being connected with said second gripper so as to cause said grippers to alterna-tely grip said cable for moving said body means in the forward direction when said mechanism is caused to expand and contract in said controlled fashion; and means acting on said piston-cylinder mechanism in a way which causes both of said grippers to move to their non-gripping positions, said last mentioned means also acting on said body means Eor pulling the latter rearward alony said cable.
The improved cable gripping apparatus disclosed herein will be described in more detail hereina:Eter in conjunction wi-th the drawing wherein.
Figure 1 is a partially broken away longitudinal sectional view of the cahle following apparatus, illus-trated in a first operating position;
Figure 2 is a view similar to Figure 1 but illustrating the cable following apparatus in a second operating position, and Figure 3 is ~ view similar to Figures 1 and 2 but illustra-ting the cable following apparatus in still a third operating position.
Turning now to the drawing, wherein like components are designated by like reference numerals throughout the various figures, a cable following apparatus is illustrated and generally designated by the reference numeral 200. This apparatus is shown having a main body including an outermost support tube or body segment 202 which is closed at its back end by means of a rear flange 204 and associated pilot spacer 206. The front end of support tube 202 carries a front end cap arrangement generally indicated at 208 which may be identical to any of the correspon-ding front cap arrangements forming part of the cable Eollowing apparatus described in the Reichman I and II applications. The specific embodiment illustrated, that is arrangement 208, is unlike those in the Reichman I and II applications but does not . .
form part of the present invention and hence is only shown gener-ally.
Continuing with the description of apparatus 200, a fron-t cable guiding tube (body segment) 226 which forms part of the apparatus body is disposed within support tube 202 and has its forwardmost end connected with front end cap arrangement 208, integrally so in the embodiment shown Bo-th tubes 202 and 226 are disposed around a given cable 227. For the reasons to be dis cussed below, the cable guiding tube 226 is disposed at the bottom end of tube 202 and includes an opening 228 in its top side wall slightly inward oE arrangement 208.
A second cable guide tube (body segment) 230 also forming part of the apparatus body is also disposed within outer-most support tube 202 in axial alignment with and directly rear-wardly of tube 226, but also around cable 227. However, tube 230 is supported within tube 202 for axial slidable movement into and out of tube 202 through the back end of the latter, that is, towards and away from the back end of tube 226. In order to pro-vide this movement of tube 230 relative to tubes 202 and 226, rear flange 204 is provided with an appropriately sized opening 232 and a guide bushing 234 as pro~ided around the opening in slidable engagement with the outer surface of tube 230. Otherwise, tube 230 slides on the inner bottom side of tube 202. For reasons to be discussed below, the slidable tube 230 includes an opening 236 in its top side wall at an intermediate point along its length, and a flange 238 is connected with and extends up from the side wall just in front of this opening~
In addition to t'he various components thus far described, ca'ble follower 200 includes a first forwardmost cable gripping device 240 and a second or rearwardmost cable gripping device 242. I'he cable gripping device 240 i5 somewhat L-shaped in configuration as shown in the drawing and is mounted within outer-most tube 202 for pivotal movement about an axis 244 between the cable engaging position shown in Figure 2 through opening 228 and a position out of engagement with the cable 227 as shown in Figures 1 and 3. A pivot pin or any other suitable means may be utilized for supporting the cable gripping device 240 in this manner 50 long as the latter is slidably movable with outermost tube 202 and guide tube 226 in the manner to be described. The rearwardmost cable gripping device 242 is similarly shaped and connected with sliding tube 230 while, at the same time, being pivotally mounted for movement between a position out of engage-ment with the cable 227 as illustrated in Figures 2 and 3 and a cable engaging position about axis 248 and into opening 236, as illustrated in Figure 1.
Overall cable following apparatus 200 also includes an arrangement generally indi.cated at 254 for causing the outermost tube or body segment 202 and its associated cable guiding tube or body segment 226 to slide forward along and relative to the cable in incremental steps in an alternating manner with tube or body segment 230. To this end, arrangement 254 includes a hydraulic cylinder arrangement 256 clisposed within outer tube 202. The hydraulic cylinder arrangement includes an outer cylinder 258 and a piston 260 telescopically movable between an extended position ~æ
and a retracted position within the back end of the cylinder. Two ports, a rear port 262 and a front port 264 are provided in cylin-der 258~ The rear port is adapted to receive fluid under pressure from an appropriate source and the ~ront port is adapted to receive fluid under pressure in the same manner, as described in more detail in the Reichman II patent application recited above.
For reasons to be discussed below, when hydraulic fluid is applied into cylinder 258 through its xearward port 262, the piston 260 is caused to move forward relative to the cylinder and, at the same time, the cylinder is forced rearwardly relative to the piston.
This presupposes that the port 264 remains open to the ambient pressure (or relieved of pressure generally) as fluid is directed into port 262. This procedure is reversed by opening the port 262 to ambient pressure and, at the same time, applying hydraulic fluid into the cylinder through port 264. This causes the cylin-der to move forward while the piston is pushed in a rearward direction. ~he way in which -this alternating movement of the piston and cylinder causes the overall apparatus to slide ~orward along the cable in incremental steps will be discussed below.
However, in order to make this happen, the front end of the cylin-der is pivotally connected to cable gripping device ~40 by a suit-able pivot means 278 such that movement of the cylinder between a rearward position and a forward position relative to previously recited axis 244 causes the entire gripping device 240 to move between its locked position shown in Figure 2 and its unlocked position shown in Figure 1. In a similar manner, the piston 260 is pivotally connected near its rearwardmost end to cable gripping device 242 b~ suitable pivot means generally indicated a-t 282.
The forwardmosk end section o~ a rod cl~vis 2~8 is utilized to make this connection. The connection between piston 260 and cable gripping device 242 is such that forward and rearward movement of -the piston relative to previously recited axis 24g causes the cable gripping device to move between its position out of engagement with the cable as shown in Figure 2 and its cable gripping position shown in Figure 1.
Overall cable following apparatus 200 as described thus far is similar structurally and functionally to the embodiment illustrated in Figures 6-9 in the Reichman II pa-tent application recited above. As discussed in this la-tter application, the appa-ratus moves in incremental steps along the cable from one end of the latter to its other end. For purposes of discussion, let it be assumed that the cable gripping devices 240 and 242 are initi-ally in the positions shown in ~igure 2 and that the port 264 is opened to ambient pressure while hydraulic fluid is being applied into the cylinder through port 262. Under these conditions, the piston 260 is moved forward and the cylinder is biased in the rearward direction. The rearward biasing of cylinder 258 causes cable gripping device 240 to lie tightly in gripping engagement with cable 227 locking tube 226 in place. At the same time, for-ward movement of piston 260 causes the cable gripping device 242 to remain out of engagement with the cable. In addition, as the piston moves forward it pulls cable gripping device 242 and cable guiding tube 230 forward with it. 'rhis movement continues until the forwardmost end of tube 230 engages the rearwardmost end of tube 226. A-t the same time, the piston is designed to be fully drawn within t'ne cylinder. Once this occurs, the port 262 opens to ambient pressure and the port 264 receives hydraulic fluid.
This causes the piston to move rearwardly a slight distance, spec-ifically enough to pivot its cable gripping device 242 into locking engagement with the cable. At the same time, the cylinder is moved forward relative to the locked in piston which, in turn, causes the cable gripping device 240 to pivot out of engagemen-t with the cable. Thus, the entire cylinder is able to continue in a forward direction, thereby -Eorcing tube 202 and 226 -forward in incremental steps relative to the loc~ed in tube 230. This ultimately places the piston in an extended position relative to the cylinder and resul-ts in a correspondingly large space between the back end of tube 226 and the front end of tube 230.
The procedure just recited is continuously repeated. In other words, the piston is moved forward into the cylinder from its extended to its retracted position while cable gripping device
The Reichman I patent application recited above specif-ically discloses a technique for replacing an existing underground cable and a specific apparatus for doing so. The apparatus includes a cable follower which is interconnected with the cable to be replaced for slidable movement along the latter. At the same time, means are provided for loosening the soil around the cable, preferably by means of one or more fluid jets. Once the soil is loosened, the cable can be easily pulled out of the ground and replaced with a new cable. A speciEic cable following arrangement is disclosed in the Reichman I application and two additional arrangements are disclosed in Reichman II. I'he most preferred one of these arrangements i5 described specifically ~n Figures 6-9 oE Reichman II and includes a telescopically conEigured main body, a pair of cable gripping mechanisms and a hydraulically actuated piston-cylinder device. The housing is disposed around the particular cable to be replaced and the piston-cylinder unit is used to cause the two cable gripping mechanisms to alternately grip and release the cable in a way s~
which causes the telescopic body to slide along the cable in a forward direction.
Each of the specific cable followers described in Reichman I and II recited above is designed to move along its associated cable in a forward direction only. For example, in the preferred embodiment described immediately above, at any time during its cable following procedurel one of the gripping mech-anisms remains in gripping engagement with its cable so that the overall cable following apparatus cannot be pu110d rearwardly along the cable. However, it has been found that there are times when it is desirable or even necessary to bring the cable following apparatus back to its starting point, for example if it malfunctions during its forward movement along the cable or if an unpenetrable obstruction lies in its forward path of movement. At the same time, it i6 desirable to retain the general configuration of the preferred cable ~ollowing apparatus disclosed in Figures 6-9 of Reichman II.
In view of the foregoing, it is one object of the pre-sent invention to provide an improved cable following apparatus of the general type described in the Reichman I and II patent appli-cations recited above but one which is capable of being moved rearwardly along an associated cable.
Another object of the present invention is to provide a cable following apparatus which moves in a forward direction along its associated cabLe in the same way as the preferred cable ~ol:Lowing apparatus recited above but which may be moved rear-..~, ,~ I
~s~
~ 3 --wardly along the cable without requiriny a complicated mechanismto accomp:Lish this.
According to one aspect of the invention there is pro-vided an apparatus for moving along the length oE an existing cable in a forward direction, comprising; a main body including first and second segments interconnected for limited slidable movement relative to one another; means for supporting said main body to said cable such that alternating slidable movement of said body segments in said forward direction causes said main body to slide forward along said cable, said supporting means including firs-t cable gripping means connected with said first bod~ segment and movable between a first position in engagement with said cable for preventing said first segment from sliding along said cable and a second position out of engagement with said cable and second cable gripping means connected with said second body segment and movable between a first position in engagement with said cable for preventing said second segment rom sliding along said cable and a second position out of engagement with said cable; means for causing said first and second body segments to slide alternately in the forward direct.ion, said slide causing means including means for maintaining said first gripping means in its cable engaging first position during sliding movement of said second segment and in its second position out of engagement with said cable during sliding movement of said first segment and, at the same time, for maintaining said second gripping means in its cable engaging first position during sliding movement of said first segment and its second position out of engagement with said cable during said sliding movemen-t of said second segment; and cable freeing means for placing both said first and second cable gripping means in their respective second positions out of engagement with said cable, at the same time, whereby said main body can be pulled rearwardly along said cable at a faster rate, said last mentioned means including rope means connected with one of said body seg-ments for pulling said main body in a rearward direction along said cable when said first and second cable gripping means are in their second positions at the same time, said slide causing means including a piston-cylinder mechanism including an outer cylinder and a piston disposed within said cylinder for movement between an extended position and a retracted position relative to said cylin-der whereby to cause the overall mechanism to expand and contract in length, means for causing said piston-cylinder mechanism to expand and contract in length in a controlled alternating fashion, and first and second means for respectively connecting said cylin-der to said first cable gripping means and said piston to said second cable gripping means such that during the expansion of said piston-cylinder mechanism, said first body segment is caused to slide forward relative to said cable while said second cable grip-ping means is maintained in its cable gripping position so as to prevent said second body segment from moving relative to said cable and such that contraction of said piston-cylinder mechanism causes saicl second body segment to slide forward relative to said cable while said first gripping means is maintained in the cable gripping position so as to prevent said firs-t body segment from moving relative to said cable, said cable freeing means including t~." `~
means for preven-ting said second cable gripping means from engaging said cable during the expansion of said piston-cylinder mechanism while at the same time maintaininy said first cable gripping means disengaged from said cable.
According to a second aspect of the invention there is provided an apparatus for moving along the length of an existing cable in a forward direction, comprising; main body means; first and second cable grippers connected with said main body means, each of said grippers being movable between one position for grip-ping said cable and a second non-gripping position; means for causing said grippers to al-ternately grip said cable in a way which causes said main body means to move in a forward direction along said cable, said last-mentioned means including a piston cylinder mechanism having an outer cylinder and a piston disposed within said cylinder for movement between an extended position and a retracted position relative to the cylinder whereby to cause the overall mechanism to expand and contract in length and means for causing the piston-cylinder mechanism to expand and contract in length in a controlled alternating fashion, said cylinder being connected with said first gripper and said piston being connected with said second gripper so as to cause said grippers to alterna-tely grip said cable for moving said body means in the forward direction when said mechanism is caused to expand and contract in said controlled fashion; and means acting on said piston-cylinder mechanism in a way which causes both of said grippers to move to their non-gripping positions, said last mentioned means also acting on said body means Eor pulling the latter rearward alony said cable.
The improved cable gripping apparatus disclosed herein will be described in more detail hereina:Eter in conjunction wi-th the drawing wherein.
Figure 1 is a partially broken away longitudinal sectional view of the cahle following apparatus, illus-trated in a first operating position;
Figure 2 is a view similar to Figure 1 but illustrating the cable following apparatus in a second operating position, and Figure 3 is ~ view similar to Figures 1 and 2 but illustra-ting the cable following apparatus in still a third operating position.
Turning now to the drawing, wherein like components are designated by like reference numerals throughout the various figures, a cable following apparatus is illustrated and generally designated by the reference numeral 200. This apparatus is shown having a main body including an outermost support tube or body segment 202 which is closed at its back end by means of a rear flange 204 and associated pilot spacer 206. The front end of support tube 202 carries a front end cap arrangement generally indicated at 208 which may be identical to any of the correspon-ding front cap arrangements forming part of the cable Eollowing apparatus described in the Reichman I and II applications. The specific embodiment illustrated, that is arrangement 208, is unlike those in the Reichman I and II applications but does not . .
form part of the present invention and hence is only shown gener-ally.
Continuing with the description of apparatus 200, a fron-t cable guiding tube (body segment) 226 which forms part of the apparatus body is disposed within support tube 202 and has its forwardmost end connected with front end cap arrangement 208, integrally so in the embodiment shown Bo-th tubes 202 and 226 are disposed around a given cable 227. For the reasons to be dis cussed below, the cable guiding tube 226 is disposed at the bottom end of tube 202 and includes an opening 228 in its top side wall slightly inward oE arrangement 208.
A second cable guide tube (body segment) 230 also forming part of the apparatus body is also disposed within outer-most support tube 202 in axial alignment with and directly rear-wardly of tube 226, but also around cable 227. However, tube 230 is supported within tube 202 for axial slidable movement into and out of tube 202 through the back end of the latter, that is, towards and away from the back end of tube 226. In order to pro-vide this movement of tube 230 relative to tubes 202 and 226, rear flange 204 is provided with an appropriately sized opening 232 and a guide bushing 234 as pro~ided around the opening in slidable engagement with the outer surface of tube 230. Otherwise, tube 230 slides on the inner bottom side of tube 202. For reasons to be discussed below, the slidable tube 230 includes an opening 236 in its top side wall at an intermediate point along its length, and a flange 238 is connected with and extends up from the side wall just in front of this opening~
In addition to t'he various components thus far described, ca'ble follower 200 includes a first forwardmost cable gripping device 240 and a second or rearwardmost cable gripping device 242. I'he cable gripping device 240 i5 somewhat L-shaped in configuration as shown in the drawing and is mounted within outer-most tube 202 for pivotal movement about an axis 244 between the cable engaging position shown in Figure 2 through opening 228 and a position out of engagement with the cable 227 as shown in Figures 1 and 3. A pivot pin or any other suitable means may be utilized for supporting the cable gripping device 240 in this manner 50 long as the latter is slidably movable with outermost tube 202 and guide tube 226 in the manner to be described. The rearwardmost cable gripping device 242 is similarly shaped and connected with sliding tube 230 while, at the same time, being pivotally mounted for movement between a position out of engage-ment with the cable 227 as illustrated in Figures 2 and 3 and a cable engaging position about axis 248 and into opening 236, as illustrated in Figure 1.
Overall cable following apparatus 200 also includes an arrangement generally indi.cated at 254 for causing the outermost tube or body segment 202 and its associated cable guiding tube or body segment 226 to slide forward along and relative to the cable in incremental steps in an alternating manner with tube or body segment 230. To this end, arrangement 254 includes a hydraulic cylinder arrangement 256 clisposed within outer tube 202. The hydraulic cylinder arrangement includes an outer cylinder 258 and a piston 260 telescopically movable between an extended position ~æ
and a retracted position within the back end of the cylinder. Two ports, a rear port 262 and a front port 264 are provided in cylin-der 258~ The rear port is adapted to receive fluid under pressure from an appropriate source and the ~ront port is adapted to receive fluid under pressure in the same manner, as described in more detail in the Reichman II patent application recited above.
For reasons to be discussed below, when hydraulic fluid is applied into cylinder 258 through its xearward port 262, the piston 260 is caused to move forward relative to the cylinder and, at the same time, the cylinder is forced rearwardly relative to the piston.
This presupposes that the port 264 remains open to the ambient pressure (or relieved of pressure generally) as fluid is directed into port 262. This procedure is reversed by opening the port 262 to ambient pressure and, at the same time, applying hydraulic fluid into the cylinder through port 264. This causes the cylin-der to move forward while the piston is pushed in a rearward direction. ~he way in which -this alternating movement of the piston and cylinder causes the overall apparatus to slide ~orward along the cable in incremental steps will be discussed below.
However, in order to make this happen, the front end of the cylin-der is pivotally connected to cable gripping device ~40 by a suit-able pivot means 278 such that movement of the cylinder between a rearward position and a forward position relative to previously recited axis 244 causes the entire gripping device 240 to move between its locked position shown in Figure 2 and its unlocked position shown in Figure 1. In a similar manner, the piston 260 is pivotally connected near its rearwardmost end to cable gripping device 242 b~ suitable pivot means generally indicated a-t 282.
The forwardmosk end section o~ a rod cl~vis 2~8 is utilized to make this connection. The connection between piston 260 and cable gripping device 242 is such that forward and rearward movement of -the piston relative to previously recited axis 24g causes the cable gripping device to move between its position out of engagement with the cable as shown in Figure 2 and its cable gripping position shown in Figure 1.
Overall cable following apparatus 200 as described thus far is similar structurally and functionally to the embodiment illustrated in Figures 6-9 in the Reichman II pa-tent application recited above. As discussed in this la-tter application, the appa-ratus moves in incremental steps along the cable from one end of the latter to its other end. For purposes of discussion, let it be assumed that the cable gripping devices 240 and 242 are initi-ally in the positions shown in ~igure 2 and that the port 264 is opened to ambient pressure while hydraulic fluid is being applied into the cylinder through port 262. Under these conditions, the piston 260 is moved forward and the cylinder is biased in the rearward direction. The rearward biasing of cylinder 258 causes cable gripping device 240 to lie tightly in gripping engagement with cable 227 locking tube 226 in place. At the same time, for-ward movement of piston 260 causes the cable gripping device 242 to remain out of engagement with the cable. In addition, as the piston moves forward it pulls cable gripping device 242 and cable guiding tube 230 forward with it. 'rhis movement continues until the forwardmost end of tube 230 engages the rearwardmost end of tube 226. A-t the same time, the piston is designed to be fully drawn within t'ne cylinder. Once this occurs, the port 262 opens to ambient pressure and the port 264 receives hydraulic fluid.
This causes the piston to move rearwardly a slight distance, spec-ifically enough to pivot its cable gripping device 242 into locking engagement with the cable. At the same time, the cylinder is moved forward relative to the locked in piston which, in turn, causes the cable gripping device 240 to pivot out of engagemen-t with the cable. Thus, the entire cylinder is able to continue in a forward direction, thereby -Eorcing tube 202 and 226 -forward in incremental steps relative to the loc~ed in tube 230. This ultimately places the piston in an extended position relative to the cylinder and resul-ts in a correspondingly large space between the back end of tube 226 and the front end of tube 230.
The procedure just recited is continuously repeated. In other words, the piston is moved forward into the cylinder from its extended to its retracted position while cable gripping device
2~0 is in its cable gripping position and the cable gripping device 242 is out of engagement with -the cable, thus, causing the tube 230 to move in incremental step forward relative to the cable. Thereafter, the cylinder 25~ is caused to move forward while the cable gripping device 242 is in its cable gripping position and the cable gripping device 240 is out of engagement with the cable, thus causing the tubes 202 and 226 to move forward an incremental step. From this pattern, it shou]d be apparent tha-t no cable gripping device engages the cable 227 during move-ment of its associated guide tube. However, at the same time, it ,~ ,, l,, should be equally apparent that one of the cable gripping devices is always in engagement with the cable as the overall apparatus moves incrementally in the forward d:irection. So long as that is the case, it is not possible to cause the apparatus to move rear-wardly, for example by means of a tow rope or the like. As will be seen below, overall apparatus 200 includes a relatively simple technique for causing cable gripping devices 240 and 242 to remain out of engagement with the cable 227, at the same time, so that the entire apparatus can be pulled rearwardly along the cable in the event -that this becomes desirable or necessary. To this extent, overall apparatus 200 differs from and is an improvement over the cable follower described in Figures 6-9 in Reichman II.
In order to release both ca*le gripping devices 240 and 242 from cable 227, overall apparatus 200 includes a rope 300 fixedly connected to the bac~ end of tube 230 by a suitable flange connector generally indicated at 302. In addition, clevis 288 includes a rearwardly extending segment 304 adapted to engage spacer 206 in the manner described hereinafter. These are the only aaditional components forming part of apparatus 200 (over and above those in the Figures 6-9 embodiment of the Reichman II
application) necessary to cause the cable gripping devices 240 and 242 to simultaneously release cable 227, as will be seen below~
In order to release cable gripping devices 240 and 2~2 from cable 227, it is necessary for the individual doing so to pull with moderate tension on :rope 300 as the cable follower moves in its normal manner in the forward direction. The operator begins initiating release of both cable gripping devices as -the J , piston-cylinder unit completes its retracting stroke during which time front gripping device 240 is in its cable gripping position and device 242 is in a disengaged position, as depicted in Figure 2. After this cycle has ended and at the beginning of the next cycle (as the piston-cylinder unit expands), the operator begins to pull tube 230 in a rearward direction (by means of rope 300) at a faster rate than the piston-cylinder unit expands. As a result, the rear gripper will not engage the ca.ble during this cycle. At the same time, the tension on tube 230 by means of rope 300 acts through cylinder 258 for preventing grippiny device 240 from dis-engaging from cable 227. However, when piston 260 reaches the ~nd of its extension stroke (entirely outwardly from the cylinder), the rearwardmost end 304 of rod clevis 288 engages spacer 206 as illustrated in Figure 3. I'his causes the cylinder to move forward relative to the piston which, in turn, forces the front gripping device 240 to disengage from cable 227. At that time, both cable gripping devices are in their cable released positions as shown in Figure 3 and the entire apparatus can be pulled rearwardly along cable 227 by means of rope 300.
~ ,;"
In order to release both ca*le gripping devices 240 and 242 from cable 227, overall apparatus 200 includes a rope 300 fixedly connected to the bac~ end of tube 230 by a suitable flange connector generally indicated at 302. In addition, clevis 288 includes a rearwardly extending segment 304 adapted to engage spacer 206 in the manner described hereinafter. These are the only aaditional components forming part of apparatus 200 (over and above those in the Figures 6-9 embodiment of the Reichman II
application) necessary to cause the cable gripping devices 240 and 242 to simultaneously release cable 227, as will be seen below~
In order to release cable gripping devices 240 and 2~2 from cable 227, it is necessary for the individual doing so to pull with moderate tension on :rope 300 as the cable follower moves in its normal manner in the forward direction. The operator begins initiating release of both cable gripping devices as -the J , piston-cylinder unit completes its retracting stroke during which time front gripping device 240 is in its cable gripping position and device 242 is in a disengaged position, as depicted in Figure 2. After this cycle has ended and at the beginning of the next cycle (as the piston-cylinder unit expands), the operator begins to pull tube 230 in a rearward direction (by means of rope 300) at a faster rate than the piston-cylinder unit expands. As a result, the rear gripper will not engage the ca.ble during this cycle. At the same time, the tension on tube 230 by means of rope 300 acts through cylinder 258 for preventing grippiny device 240 from dis-engaging from cable 227. However, when piston 260 reaches the ~nd of its extension stroke (entirely outwardly from the cylinder), the rearwardmost end 304 of rod clevis 288 engages spacer 206 as illustrated in Figure 3. I'his causes the cylinder to move forward relative to the piston which, in turn, forces the front gripping device 240 to disengage from cable 227. At that time, both cable gripping devices are in their cable released positions as shown in Figure 3 and the entire apparatus can be pulled rearwardly along cable 227 by means of rope 300.
~ ,;"
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for moving along the length of an existing cable in a forward direction, comprising; a main body including first and second segments interconnected for limited slidable movement relative to one another; means for supporting said main body to said cable such that alternating slidable movement of said body segments in said forward direction causes said main body to slide forward along said cable, said supporting means including first cable gripping means connected with said first body segment and movable between a first position in engagement with said cable for preventing said first segment from sliding along said cable and a second position out of engagement with said cable and second cable gripping means connected with said second body segment and movable between a first position in engagement with said cable for preventing said second segment from sliding along said cable and a second position out of engagement with said cable; means for causing said first and second body segments to slide alternately in the forward direction, said slide causing means including means for maintaining said first gripping means in its cable engaging first position during sliding movement of said second segment and in its second position out of engagement with said cable during sliding movement of said first segment and, at the same time, for maintaining said second gripping means in its cable engaging first position during sliding movement of said first segment and its second position out of engagement with said cable during said sliding movement of said second segment; and cable freeing means for placing both said first and second cable gripping means in their respective second positions out of engagement with said cable, at the same time, whereby said main body can be pulled rearwardly along said cable at a faster rate, said last mentioned means including rope means connected with one of said body segments for pulling said main body in a rearward direction along said cable when said first and second cable gripping means are in their second positions at the same time, said slide causing means including a piston-cylinder mechanism including an outer cylinder and a piston disposed within said cylinder for movement between an extended position and a retracted position relative to said cylinder whereby to cause the overall mechanism to expand and contract in length, means for causing said piston-cylinder mecha-nism to expand and contract in length in a controlled alternating fashion, and first and second means for respectively connecting said cylinder to said first cable gripping means and said piston to said second cable gripping means such that during the expansion of said piston-cylinder mechanism, said first body segment is caused to slide forward relative to said cable while said second cable gripping means is maintained in its cable gripping position so as to prevent said second body segment from moving relative to said cable and such that contraction of said piston-cylinder mech-anism causes said second body segment to slide forward relative to said cable while said first gripping means is maintained in the cable gripping position so as to prevent said first body segment from moving relative to said cable, said cable freeing means including means for preventing said second cable gripping means from engaging said cable during the expansion of said piston-cylinder mechanism while at the same time maintaining said first cable gripping means disengaged from said cable.
2. An apparatus for moving along the length of an existing cable in a forward direction, comprising; main body means; first and second cable grippers connected with said main body means, each of said grippers being movable between one position for gripping said cable and a second non-gripping position; means for causing said grippers to alternately grip said cable in a way which causes said main body means to move in a forward direction along said cable, said last-mentioned means including a piston-cylinder mechanism having an outer cylinder and a piston disposed within said cylinder for movement between an extended position and a retracted position relative to the cylinder whereby to cause the overall mechanism to expand and contract in length and means for causing the piston-cylinder mechanism to expand and contract in length in a controlled alternating fashion, said cylinder being connected with said first gripper and said piston being connected with said second gripper so as to cause said grippers to alterna-tely grip said cable for moving said body means in the forward direction when said mechanism is caused to expand and contract in said controlled fashion; and means acting on said piston-cylinder mechanism in a way which causes both of said grippers to move to their non-gripping positions, said last mentioned means also acting on said body means for pulling the latter rearward along said cable.
3. An apparatus according to Claim 1. wherein said preventing means includes rope means connected with said second body segment for pulling the latter rearwardly after the expansion of said piston-cylinder mechanism at a speed at least equal to the rear-ward movement of said piston, whereby the entire main body is simultaneously pulled rearwardly along the cable.
4. An apparatus according to Claim 1 wherein said preventing means includes a rod clevis carried by said piston and engagable against said first body segment before said piston-cylinder mecha-nism is entirely expanded as said second body segment is pulled rearwardly in order to cause said first cable gripping means to become disengaged from said cable.
5. An apparatus according to Claim 4 wherein said first cable gripping means is pivotally connected at one point to said first body segment and at a second point to said cylinder, wherein said second cable gripping means is connected at one point to said second body segment and at a second point to said piston such that the initial expansion of said piston-cylinder mechanism from its contracted position simultaneously causes said first cable gripping means to pivotally move from its cable gripping position to a position out of engagement with said cable and said second cable gripping means to pivotally move from its position out of engagement with said cable to its cable gripping position and such that contraction of said piston-cylinder mechanism from its expanded position simultaneously causes said first gripping means to pivotally move from its position out of engagement with said cable to its cable engaging position and said second cable gripping means to pivotally move from its cable gripping position to a position out of engagement with said cable, and wherein said pulling of said second body segment rearwardly prevents said second gripping means from pivoting to its cable gripping position during expansion of said piston-cylinder mechanism.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US41448382A | 1982-09-02 | 1982-09-02 | |
| US414,483 | 1982-09-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195516A true CA1195516A (en) | 1985-10-22 |
Family
ID=23641644
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000434419A Expired CA1195516A (en) | 1982-09-02 | 1983-08-11 | Cable gripping apparatus having forward and rearward movement capabilities |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5963911A (en) |
| AU (1) | AU555698B2 (en) |
| CA (1) | CA1195516A (en) |
| DE (1) | DE3331292C2 (en) |
| FR (1) | FR2532669B1 (en) |
| GB (1) | GB2126800B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4593772A (en) * | 1982-09-02 | 1986-06-10 | Electric Power Research Institute, Inc. | Rotary cutter for cable following apparatus |
| GB2171485A (en) * | 1985-02-27 | 1986-08-28 | British Gas Corp | Mole or pig |
| DE19504484C1 (en) * | 1995-02-10 | 1996-09-19 | Flowtex Technologie Import Von | Equipment for removing earth around buried cables or empty pipes |
| NL1015729C2 (en) | 2000-07-17 | 2002-01-18 | Koninkl Kpn Nv | Method for installing a duct and device for performing this method in the ground. |
| AT507239B1 (en) | 2008-09-08 | 2011-02-15 | Pichler Alois | METHOD AND DEVICE FOR EXTRACTING CABLE ELEMENTS FROM CABLE TUBES IN CABLE HOLES |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4385667A (en) * | 1980-10-14 | 1983-05-31 | Electric Power Research Institute, Inc. | Cable reaming apparatus |
| US4403667A (en) * | 1981-08-03 | 1983-09-13 | Electric Power Research Institute, Inc. | Cable following apparatus utilizing a releasable cable gripping mechanism |
| JPS5846928A (en) * | 1981-09-14 | 1983-03-18 | オリンパス光学工業株式会社 | Endoscope |
-
1983
- 1983-08-11 CA CA000434419A patent/CA1195516A/en not_active Expired
- 1983-08-16 AU AU18046/83A patent/AU555698B2/en not_active Ceased
- 1983-08-18 GB GB08322316A patent/GB2126800B/en not_active Expired
- 1983-08-31 DE DE19833331292 patent/DE3331292C2/en not_active Expired
- 1983-09-01 FR FR8314030A patent/FR2532669B1/en not_active Expired
- 1983-09-02 JP JP58161819A patent/JPS5963911A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| AU1804683A (en) | 1984-03-08 |
| JPS5963911A (en) | 1984-04-11 |
| FR2532669B1 (en) | 1985-08-16 |
| DE3331292A1 (en) | 1984-03-29 |
| AU555698B2 (en) | 1986-10-02 |
| FR2532669A1 (en) | 1984-03-09 |
| JPH0150163B2 (en) | 1989-10-27 |
| GB2126800B (en) | 1985-10-23 |
| GB2126800A (en) | 1984-03-28 |
| DE3331292C2 (en) | 1986-05-28 |
| GB8322316D0 (en) | 1983-09-21 |
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| MKEC | Expiry (correction) | ||
| MKEX | Expiry |