GB2182302A - Electric cable handling system - Google Patents

Abstract

A system for handling an electric cable 14 which extends between a terminal unit 13 and a machine, so as to prevent the cable 14 from being fouled by the machine 10, includes a track rail 17 comprising aligned separate elements, and wheeled carriers 15, 16 for the cable 14. Constant tension biassing devices 22 extend between adjacent carriers 15, and non-extensible flexible connections 20 extend between all of the carriers 15, 16 to prevent tension in the cable 14. Spring biassed retarding devices 18 on the track 17 permit free movement of the carriers 15, 16 towards the unit 13, but prevent movement of the carriers 15, 16 in the opposite direction until they are pulled successively past the devices 18 by the machine 10, acting through the connections 20. <IMAGE>

Description

SPECIFICATION Electric cable handling system This invention relates to a system for handling electriccables, and in particularto such a system when intended for use in the mining industry.

In underground mining a heading machine is used to excavate a tunnel, and electric powerthrough the heading machine is byway of a flexible cablewhich extends back along the tunnel to a terminal box. It is desirable that the cable is kept out of the path ofthe heading machine, since extensive damage can be caused to the cable if it is run over orfouled bythe machine. It is known to suspend cable in loops from carriers on an overhead track so thatthese can be pulled along by advance of a machinetowhichthey are connected. This arrangement can result in problems when the machine reverses and is required to push backthe loopsofcable,whichcanthenfoul some part of the machine, causing hazard to both the cable and the machine.Additionally, when the excavated tunnel has a downward gradienttowards its headendthecableloopswill accumulate atthe lower end of the track, increasing the hazards to the cable and machine. Since the cables are frequently of large size, and many turns ofthe cable can accumulate in this way, it will be difficult to push the cables backup a gradient without risk of damage or of jamming the cable carriers in the track.

It is an object of the present invention to provide a cable handling system in which the foregoing problems are overcome.

It is desirable that the handling system shall be capable of rapid and accurate dismantling and reassemblyto enable ittd advancewith the heading machine as soon as the extent of the flexible cable is reached. The present invention provides a system which will also meet th is requirement.

According to the invention there is provided an el ectriccable handling system including a monorail track comprising a plurality of discrete track elements, means for coupling said elements end to end, a pluralityofcable carriers freely movable on said track, each said carrier having means for secur- ing a cable thereto, and a constant tension biasing device interconnecting at least one pair of said carriers.

Embodiments of the invention will now be described byway of example only and with reference to the accompanying drawings in which: Figure 1 shows a cable handling system at an initial stage of operation, Figure 2 shows the system of Figure 1 at a subsequent stage of operation, Figure 3 is a diagrammatic side elevation of a cable supported on a track by one form of carrier, Figure4 is an elevation of a cable supported by anotherform of carrier, Figure 5is a vertical section through a track el ementforming part of Figure 1, Figure 6 shows a method of secu ring and supporting the ends ofadjacenttrackelements, Figure 7 is a section through a trackelementshow- ing a relatively movable support in place thereon, Figure 8,9 and 10 show operating conditions of a retarder device forming part of the system of Figure 1, Figure 11 is a pictoral view of an alternative form of cable carrier, and Figure 12 is a section on line 12-12 in Figure 11.

In Figure 1 a heading machine 10 is shown operating at the face of a mine tunnel 11. It should be noted that in this example the tunnel 11 slopes downwardly towards its head end. An electrical supply to the machine 10 is provided from a source through a rigid cablel2toaterminalboxl3andthencethrougha flexible electrical cable 1 4to the machine 10. The cable 14 is secured to wheeled carriers 15, 16 which run in a track 17 composed of a pluralityofsubstanti- ally identical aligned track elements which are secured end to end and suspended from flanged beams of the roof of the tunnel 11.Spring loaded retarder devices 18, to be described in detail with reference to Figures 6-8, are provided on the track elements and restrain the carriers 15, 16 from moving towards the head end ofthetunnel 11 until pulled successively past each device 18 by the machine 10. The devices 18 also prevent the carriers 15,16, and the cable 14 carried thereby, from running downhill.

Non-extensible loops 20 of chain or non-electrical cable, shown in Figure 2 extend between each adjacent two of the carriers 15, 16 and have lengths less than that of the cable 14 between those carriers, thereby preventing strain from being imposed on the cable 14when the carriers 15,16 move apart.

As shown in Figure 3 each ofthe carriers 15 includes a reel 21 on which is wound a constant force extension spring 22, the free end of the spring 22 being pivotally secured to a next adjacent carrier 15. The number of carriers 15 and thetotal lengths ofthe cable 14 between them are such as to accommodate the reversing travel of the machine 10 during its oper ation. The carriers 16, as shown in Figure 1,2and4, are not provided with tension springs and are not required to retract when the machine 10 reverses.

In use, as indicated in Figure 2, one of the carriers 15 can abut a retarder device 18 and the carriers 15 on the tunnel head side of the retarded carriers are retracted by the springs 22 or extended by the machine 10 as the latter operates. The carriers 15, 16 are prevented from moving downthetunnel by one or more further retarder devices 18, until pulled successively past these latter devices 18 by tension in the chains 20 as the machine 10 advances. This advance is accompanied by assembly of additional elements of the track 17 at the head end of the system, both end elements of the track 17 being provided with stops 23 which preventthecarriers 15,16from leaving the track 17. When the cable 14 is substantially fully extended, the terminal box 13 is disconnected from the fixed cable 12 and advanced with the carriers 15, 16 to a forward position having a configuration which corresponds to that of Figure 1. The terminal box 13 is reconnected to an extended length of the cable 12 and the operations described above are repeated until the required length oftunnel has been driven.

Each track element, indicated at 30 in Figure 5, is of square box section, as shown more clearly in Figure 7, and is provided with an opening 31 which extends overthewhole length of the element 30 sothatthe element 30 provides a monorail track. One end 32 of each element 30 carries an offset flange 33 spaced from the end face ofthe element. The otherend 34of each element 30 has an enlarged recess 35 for receiving an end 32 of an adjacent element 30. The recess 35 has sufficient clearance relative to the ends 32 as to permit a limited axial misalignment between adjacent elements 30 without affecting the ability of the carriers 15, 16 to pass freely between the elements 30.The end 34 has aflange36, similar inform to the flange 33 and the length of the recess 35 is sufficient to allowtheflanges 33,36 of adjacent elements to abut, as shown in Figure 6. Theflanges 33,36 have through holes 37 which are aligned when adjacent elements 30 are properly mated. A bolt shackle 38 passes through the holes 37, the spacing between the arms ofthe shackle 38 being such as to maintain the flanges 33,36 in, or near, abutment. The lengths ofthe elements 30 are such as to permit easy manual handling and preferably also correspond to a multiple of the standard pitches of roof supports for the tunnel 11. The shackle 38 provides a point to which a screw clamp 39 can be attached, for suspending the track 17 from a roof support as aforesaid.

Hangers 40, as shown in Figure 7, have shapes cor- responding to that of the flanges 33,36 but are freely slidable lengthwise of the elements 30. One or more of the hangers 40 will normally be assembled on each ofthe elements 30 and, in conjunction with clamps 39, provide added supports for the track 17 at convenient roof support locations.

Each retarder device 18 comprises, as shown in Figure 8-10, a plungerSOslidable in a body 51 which is pivotally mounted in a housing 52,the housing 52 being secured to atrack element 30. The plunger 50 is biased by a spring 53 to project into the paths ofthe carriers 15, so as to be displaced againstthe spring 53 by the carriers as the latter move in the direction indicated by the arrow H towards the head end of the tunnel 1 1,this action being shown in Figure 9.

Movement of a carrier in the reverse direction, as shown in Figure 10, causes the plunger 50 to be pivo- ted out ofthe path of the carrier and thereby to have no retarding effect. The pivotal axis 54 of the housing 52 is offsetfrom the line of action of the plunger50 so that the latter will readily return from the position shown in Figure lOtothe position in shown in Figure 8. An adjuster screw 55 is operable to maintain the plunger 50 in the position shown in Figure 10 so that the carriers 15, may move freely in either direction.In this mode of operation at least one retarder device 18 or other stop must be provied at a location as shown atA in Figure 1 and 2, so as to be abutted by one ofthe carriers 15 or 16, to cause the carriers 15to retract as described above. The housing 52 includes a removable cover plate 56 to prevent settlement of dirt and to permit cieaning and servicing.

Reverting to Figures 3 and 4, each of the carriers 15, 16 includes a cable clamp 60 mounted by means of a swivel 61 on a link62 which is in turn mounted bya pivot 63 on a plate 64. The swivel 61 and pivot 63 thus provide a universal joint between the clamp 60 and plate 64. The plate 64 is supported by rollers 65 in the track 17. In use,thecable 14will initially be coiled so thatthe axis of the coil is parallel to the long axis of the track 17 adjacent the terminal box 13. Turns of the cable coil are secured to the clamps 60 in turn, starting with the carrier 15 nearest the head end ofthe tunnel 17.The turns of the cable 14will thus initially lie transverse to the tunnel 11 and are subsequently pulled outtothe configuration shown in Figure 2.As the machine 10 reverses, or when the terminal box 13 is advanced upthetunnel 1 1,thecable 14will tend to re-coil to its original configuration, thereby stowing in a minimum length ofthetunnel 11.

An alternative form of the carrier 15 is shown in Figures 11 and 12 and comprises a plate 70 having a rectangularthrough hole 71 therein for receiving a housing 72 for a constant torque spring motor 73. As shown in Figure 12 the torque output drum 74 ofthe motor 73 has a spool 75 secured thereto. A relatively thin wire cable76 iswound onthe spool 75 and passes through a steel grommet 77. The free end of the cable 76 is secured to a part 78 on the plate 70 of the next preceding carrier 15. The cable 76 is less li- able to damage than the spring 22 shown in Figure 3, and even if distorted will rewind on the spool 75. The plate 70 carries a cable clamp 60 by means of a universal coupling 61,62 ofthe type described above.

Claims (3)

1. An electric cable handling system including a monorail track comprising a plurality of discrete track elements, means for coupling said elements end to end, a plurality of wheeled carriers for said electric cable freely movable on said track, each said carrier having means for securing said electric cable thereto, and a constant tension biasing device interconnecting at least one pair of said carriers.

2. As system as claimed in Claim 1 in which said biasing device comprises a constant force extension spring.

3. Asystem as claimed in Claim 1 in which said biasing device comprises a constant torque spring motor on one of said pair of carriers, a cable drum rotatable by said motor and a cable wound on said drum and extending to the other of said pair ofcar- riers.

3. AsystemasclaimedinClaiml inwhichsaid biasing device comprises a constant torque spring motor on each of said pair of carriers, a cable drum rotatable by said motor and a cable wound on said drum and extending to the other of said pair of carriers.

4. A system as claimed in any preceding claim which includes a plurality of said biasing devices interconnecting a plurality of adjacent pairs of said carriers.

5. A system as claimed in any preceding claim which includes means for limiting separation of said carriers on said track.

6. A system as claimed in any preceding claim in which said means for securing said electric cable comprises a clamp mounted on said carrierfor pivotal movement about a first axis normal to the long axis of said track.

7. A system as claimed in Claim 6 in which said clamp is also pivotal about a second axis normal to said first axis.

8. A system as claimed in any preceding claim in which at least one of said track elements includes means for retarding movement of said carriers in one' direction of movement relative to said track.

9. Asystem as claimed in Claim 8 in which said retarding means comprises a latch biased by a spring to engage a carrier and displaceable against the spr- ing bias by a predetermined force urging said carrier along said track.

10. A system as claimed in Claim 9 in which said latch is pivotable to allow free movement of said carriers in the other direction of movement along said track.

11. Asystem as claimed in Claim 10 which includes means for retaining said latch in its pivoted posi tion,to allowfree movementofsaid carriers in both of said directions.

12. A system as claimed in any preceding claim in which said means for coupling said track elements end to end comprises flanges at respective ends of said elements, means for maintaining said elements substantially in alignment and means for holding the flanges of adjacent elements in close proximity.

13. A system as claimed in Claim 12 in which said means for holding the track elements substantially in alignment comprises a male and female portion at respective ends of each said element, said male and female portions having sufficient clearance to allow a limited axial misalignment between adjacent track elements.

14. Asystem as claimed in Claim 12 or Claim 13 in which said means for holding said flanges in pro ximity comprises a shackle for attachment to an overhead structure, said shackle having a limited clearance across two adjacent flanges.

Amendments to the claims have been filed, and have the following effect: *(a) Claims 1 and 3 above have been deleted ortextually amended.

*(b) Newortextually amended claims have been filed as follows: Claims 1 and 3 attached CLAIMS

1. An electric cable handling system including a monorail track comprising a plurality of discrete track elements, means for coupling said elements end to end, a plurality of wheeled carriers for said electric cable freely movable on said track, each said carrier having means for fixedly clamping said elec- tric cable thereto, and a constanttension biasing de- vice interconnecting at least one pair of said carriers.