GB2197817A - Electrical linesman's operating pole - Google Patents

Abstract

An electrical linesman's operating pole for facilitating attachment of a cable clamp (6) to, and detachment of the cable clamp from, an overhead power supply line includes at least two releasably connected pole lengths (1) and a hook 5 (12) for engaging the clamp. The hook (12) which is longitudinally slidable in a first guide (13) is resiliently biassed axially outwardly from the end of the pole. A second guide (18) which intersects the first guide (13), receives part (11) of the cable clamp after engagement of the part (11) with the hook and withdrawal of the hook into the first guide. Engagement of the second guide with the clamp allows the clamp to be screwed onto or off the power line on rotation of the pole. An operating means to draw the hook (12) down into its guide includes a sleeve (19) coupled to an operating rod (20) inside the pole which in turn is coupled to the hook. In use, a cable clamp can be held rigidly by the pole whilst the clamp is being hooked on and off and clamped to and released from an overhead power supply line. <IMAGE>

Description

ELECTRICAL LINES1AN'S OPERATING PCLE This invention relates to an electrical linesman's operating pole for facilitating attachment of a cable clamp to, and detachment of the cable clamp from, an overhead power supply line. Such a pole has one end electrically isolated from its other and can be used, for example, to attach a cable clamp to an overhead power line, the cable clamp having a dropper or downlead attached to it to bring power down from the overhead line (perhaps having a voltage of 11rev or 66Kv) to supply electrical means on the ground such as a transformer.Such cable clamps with associated droppers are also fitted to overhead power lines when linesmen are working on them, the downleads being electrically connected to earthing stakes driven in the ground or to an earthing system to ensure that any inadvertent charging of the power lines is automatically discharged to earth to protect the linesmen. Naturally, when the power lines are charged, a reliable means must be used to clamp the clamps to the charged power lines whilst ensuring that the user is electrically isolated therefrom.

Various types of linesmen's poles are known. For example, there is a bayonet type where the clamp is first attached to the end of the pole by a press-and-turn operation and then hooked-up over the power line and then clamped thereon by twisting the pole which tightens the clamp on the line. The pole is then removed from the clamp by a press-and-turn operation leaving the clamp complete with downlead firmly attached to the overhead line. To remove the clamp using such a pole, a press-and-turn operation is again utilised to attach the pole to the clamp and then the pole is again twisted to unscrew the clamp to release it from the power line.

The bayonet structure requiring the press-and-turn operation is unsatisfactory in certain circumstances particularly because of the way the overhead power line can swing in the air. Accordingly, the pole user probably would have to pull on the dropper to provide some tension when trying to remove the clamp. To remove the clamp can also be difficult in that the user has to locate the end of the clamp in the receiving bayonet socket of the pole and then push upwardly and twist to engage the end of the clamp and then unscrewing the clamp from the overhead line.

Sometimes a cable clamp is required to be fixed to a dropper and this is even more difficult to attach and remove since the dropper is invariably slack.

Another form of linesman's pole has a hook at one end which is used to engage a ring on the end of the cable clamp so that by retracting the hook back into the inside of the pole, the ring is caught in a somewhat loose fashion on the end Q the pole which makes it somewhat difficult in practice to hang the clamp on the power line. The hook is operated by means near the end of the pole remote from the hook, the operating means including a sleeve slidably mounted on the pole and connected to rodding of electrically insulating material which acts on the hook to open or close it about a cable clamp. The sleeve can be engaged in various positions longitudinally on the pole by means of a tooth and rack mechanism. This form of pole is formed as two pole lengths pivoted to one another so that the pole can be folded in half for transport and stowage.

Generally, a linesman's pole is about eight feet (2.44 m) in length and so the known pole can be folded into two four foot (1.22 m) lengths for transport or stowage. However, it is desirable sometimes that such a pole should be able to receive one or more four foot (1.22 m) extension lengths to bring the total length up to at least sixteen feet (4.88 m). This is not easily achievable with known linesmen's poles because of the semi-permanent connections between the two pole lengths.

According to a first aspect of the present invention, there is provided an electrical linesman's operating pole for facilitating attachment of a cable clamp to, and detachment of the cable clamp from, an overhead power supply line, the pole including two pole lengths, one of these lengths having a cable clamp engaging means at its outermost end and there being releasable means enabling the innermost end of said one length to be releasably connected to one end of the other of said pole lengths or to an intermediate pole length for interpositioning between said two pole lengths, and said other pole length carrying means for operating said cable clamp engaging means.

The cable clamp engaging means may comprise a hook portion at one end of the pole, said hook portion being slidable in a first guide in said one end longitudinally of the pole and being normally urged resiliently and longitudinally outwards therefrom ready to receive part of a said cable clamp to be hung on the hook portion and said one end of the pole having a second guide in said one end of the pole, said second guide intersecting said first guide, said second guide being for receiving said part of a said cable clamp when it is enraged by said engaging means, the arrangement being such that, in use, said hook portion can be drawn against its resilient bias by said operating means into said first guide whilst drawing with it said part of said cable clamp thereby trapping in substantially non-rotatable fashion said part in said second guide.

According to another aspect of the present invention, there is provided an electrical linesman's operating pole for facilitating attachment of a cable clamp to, and detachment of the cable clamp from, an overhead power supply line, the pole including a cable clamp engaging means at one end and means for operating said cable clamp engaging means, said cable clamp engaging means comprising a toox portion at saio one end of the pole, said hook portion being slidable in a first guide in said one end longitudinally of the pole and being normally urged resiliently and longitudinally outwards therefrom ready to receive part of a said cable clamp to be hung on the hook portion and said one end of the pole having a second guide in said one end of the pole, said second guide intersecting said first guide, said second guide being for receiving said part of a said cable clamp when it is engaged by said engaging means, the arrangement being such that, in use, said hook portion can be drawn against its resilient bias by said operating means into said first guide whilst drawing with it said part of said cable clamp thereby trapping in substantially non-rotatable fashion said part in said second guide.

In a pole according to the first or second aspect of the invention, said means for operating said cable clamping engaging means can be in the form of a slidable sleeve mounted about the po'e remote from said cable clamp engaging means, said sleeve being coupled to a first length of an operating rod inside the second pole length which in turn is releasably coupled to one end of a second length of operating rod inside the first pole length, said cable clamp engaging means being joined to said second length of operating rod and thereby being operable by said operating means. The rods can be of square section.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a diagrammatic side view of an electrical linesman's operating pole, Figure 2 is an enlarged top plan view of the pole shown in Figure 1, Figure 3 is a cross-secticnal side view of the top cf the pole and illustrating how a cable clamp with dropper can be attached thereto, Figure 4 is a view sinilar to Figure 3 but shows the cable clamp secured to the top of the pole, Figure 5 is a side view of the part of the pole and cable clamp shown in Figure 4 and is illustrated at right angles to the view shown in Figure 4, Figures 6 and 7 are two views at right angles to one another to illustrate how two pole lengths of the pole can be joined together, and Figures 8 and 9 are two views illustrating first and second positions of part of a clamp operating means.

Referring to the drawings, the electrical linesman's operating pole illustrated has two four foot (1.22 m) pole lengths 1 and 2 releasably connected at 3 to one another. Each pole length is made of a material which has high electrical insulating properties and high resistance to electrical flash-over.

Each pole length 1, 2 is hollow and the joining means illustrated at 3 includes a reduced-diameter portion 2A protruding from the end of the pole length 2 and fitting inside the adjacent end of the pole length 1.

Diametrically-opposed lobes 4 extend inwards in the pole length 1 and engage in corresponding bayonet slots 4A in the portion 2A thereby to hold the pole lengths 1 and 2 securely together in axial alignment.

Resiliently biassed lobes extend out through respective apertures in the pole length 1 from the portion 2A when the bayonet connection is made to prevent relative rotation between the pole lengths.

The upper (outermost) end of the pole has a cable clamp engaging means 5 to engage a cable clamp 6 which is intended to be attached to and detached from an overhead power supply line 7. The cable clamp 6 includes a downlead 8 for the purposes as aforesaid and an overhead power supply line engaging hook portion 9 with a threaded clamping means 10 which can be screwed up as illustrated in Figure 4 to clamp the overhead supply line 7 securely in good electrical contact in the hook portion 9. Part of the clamping means 10 is in the form of a ring 11 so that it can be engaged by the linesman's pole.

The cable clamp engaging means 5 of the pole comprises an operating head which includes a hook portion 12 having a form rather like a shepherd's crook, this hook portion 12 extending out of the upper end of the head and being slidable in an open-fronted, transverse guide 13 which extends from the top end of the head longitudinally down into the head, there being a lug 14 extending from the hook portion 12, this lug 14 being able to slide in a slot 15 in the wall of the head, the lug 14 and slot 15 interacting to limit longitudinal movement of the hook portion 12. The hook portion 12 is resiliently biassed axially outwardly from the end of the head by means of a compression spring 16 acting between the hook portion 12 and a shoulder 17 fitted in the bore of the head.

A second transverse guide 18, which intersects the guide 13, also extends longitudinally of the head from its top and is able to receive the ring 11 on the cable clamp when the ring 11 is engaged by the hook portion 12.

Means are provided to draw the hook portion 12 against the resilient bias of the spring 16 into the guide 13. Figures 8 and 9 illustrate part of an operating means in the form of a sleeve 19 slideably mounted about the lower pole length 2, the sleeve being coupled via a pin or screw 24 slid able in a longitudinal slot 25 in the pole length 2, to a first length of an operating rod 20 inside the pole length 2 which in turn is releasably coupled to a second length of operating rod 21 inside the pole length 1. This second length of rod is operatively joined to the cable clamp engaging means at the base of the hook portion 12.

The means for releasably coupling the first length of rod 20 to the second length of rod 21 comprises pins 22 on the rod 20 engaging on bayonet slots 23 on the rod 21. Thus there is a double bayonet connection between the pole lengths 1 and 2 and the rods 20 and 21. Of course, the operating mechanism is electrically isolated from the clamp engaging means 5.

It will be appreciated that the pole lengths and rods can be connected and disconnected at will to facilitate dismantling of the pole or to add another length to it.

The position of the sleeve 19 shown in Figure 9 and in full lines in Figure 1 is the position where the rods 20 and 21 are under tension and the hook portion 12 has been drawn down into its guide 13 against the resilient bias of the spring 16, the position of the hook portion 12 in Figure 1 in this condition also being shown in full lines.

To assemble the linesman's pole for use, presuming that the user starts from two disconnected pole lengths 1 and 2 with their associated parts and fittings already mounted thereon, the pole lengths 1 and 2 are simply aligned with one another and the reduced diameter portion 2A is pushed into the end of the pole length 1 and twisted until the bayonet connections are made and the resiliently biassed lobes are engaged in their respective apertures. Should it be necessary to insert an additional pole length (not shown) between the pole lengths 1 and 2, then this is simply achieved by disconnecting the pole lengths 1 and 2 and then a similarly-equipped intermediate pole length can be joined on to the pole lengths 1 and 2 with associated rodding on the intermediate pole length then forming part of the means for operating the cable clamp engaging means.

With or without the intermediate pole length, the means of operating the pole when assembled is as follows. With the hook portion 12 being in its position ready to receive a cable clamp 6, the situation is as shown in Figure 3 with the sleeve 19 and hook portion 12 being as shown in Figure 8 and in chain-dot lines in Figure 1. The clamping means 10 of the cable clamp 6 is unscrewed as shown in Figure 3 ready to be hooked over an overhead power supply line and the hook portion 12 is hooked through the ring 11 of the cable clamp 6 until the ring 11 nests in the hook portion 12. If the pole is held substantlal3y horizontally with the prong of the hook 12 pointing upwardly, it will be seen that this step can be achieved easily.

The sleeve 19 is then drawn into the position shown in Figure 9 and in full lines in Figure 1 where a resiliently biassed lobe 26 springs out through an aperture 27 in the sleeve 19 to hold the sleeve in this position, this movement of the sleeve causing the rods to draw the hook portion 12 down into its guide 13 against the bias of the spring 16, the hook portion 12 dragging with it the ring 11 of the cable clamp 6.

The ring 11, extending as it will substantially at right angles to the plane of the hook portion 12, is dragged and guided down into its guide 18. This has the effect of bringing the clamping means 10 substantially into axial alignment with the pole as shown in Figures 4 and 5 and thus the cable clamp 6 is held substantially rigidly on the end of the pole 1.

In this condition, the pole can be lifted by the linesman to hook the portion 9 of the cable clamp 6 over an overhead power supply line 7 and then the pole is twisted in the direction of the arrow shown in Figure 4 to screw the clamping means 10 until its head tightens against the underside of the overhead power supply line 7, thereby securing the clamp 6 in place, whilst of course the line 7 is satisfactorily electrically connected to the downlead 8.All that then needs to be done is to release the tension on the rods by pressing the lobe 26 in and drawing the sleeve 19 up to the position shown in Figure 8 and in chain-dot lines in Figure 1 where the lobe 26 springs out through an aperture 28 in the sleeve 19 and this allows the spring 16 to eject the hook portion 12 and cable clamp ring 11 from their guides in the top of the pole so that the pole can then easily be unhooked from the cable clamp 6 leaving that in position on the line 7.

The reverse procedure is followed to remove the clamp 6 from the line 7.

It will be appreciated that the present construction is comparatively inexpensive to produce, provides an improved positioning of the hook insofar as engagement of the clamp 6 is concerned and enables the clamp 6 to be held rigidly whilst it is being hooked on and off and being clamped to and released from an overhead power supply line 7, whilst using an uncomplicated operating mechanism.

Claims (13)

CLLISfS:

1. An electrical linesman's operating pole for facilitating attachment of a cable clamp to, and detachment of the cable clamp from, an overhead power supply line, the pole including two pole lengths, one of these lengths having a cable clamp engaging means at its outermost end and there being releasable means enabling the innermost end of said one length to be releasably connected to one end of the other of said pole lengths or to an intermediate pole length for interpositioning between said two pole lengths, and said other pole length carrying means for operating said cable clamp engaging means.

2. A pole according to claim 1, wherein said cable clamp engaging means comprises a hook portion at one end of the pole, said hook portion being slid able in a first guide in said one end longitudinally of the pole and being normally urged resiliently and longitudinally outwards therefrom ready to receive part of a said cable clamp to be hung on the hook portion and said one end of the pole having a second guide, said second guide intersecting said first guide and being for receiving said part of a said cable clamp when it is engaged by said engaging means, the arrangement being such that, in use, said hook portion can be drawn against its resilient bias by said operating means into said first guide whilst drawing with it said part of said cable clamp, thereby trapping in substantially non-rotatable fashion said part in said second guide.

3. A pole according to claim 2, wherein said first guide is open-fronted so as to allow for the passage of the free end of said hook portion into the pole.

4. A pole according to claim 1, 2 or 3, wherein said means for operating said cable clamp engaging means is in the form of a slid able sleeve mounted about the pole remote from said cable clamp engaging means, said sleeve being coupled to a first length of an operating rod inside the second pole length which in turn is releasably coupled to one end of a second length of operating rod inside the first pole length, said cable clamp engaging means being joined to said second length of operating rod and thereby being operable by said operating means.

5. A pole according to claim 4, wherein said operating rod lengths are of insulating material.

6. A pole according to any one of the preceding claims, wherein said releasable means includes a reduced-diameter portion on one pole length fitting inside the adjacent end of the other pole length, there being diametrically-opposed lobes extending inwards in one pole length for engagement in corresponding bayonet slots in said reduced-diameter portion, thereby to hold the two pole lengths securely together in axial alignment, and there being resiliently biassed lobes extending out through said other pole length from said reduced-diameter portion when the bayonet connection is made to prevent relative rotation between the two pole lengths.

7. An electrical linesman's operating pole for facilitating attachment of a cable clamp to, and detachment of the cable clamp from, an overhead power supply line, the pole including a cable clamp engaging means at one end and means for operating said cable clarp engaging means, said cable clamp engaging means comprising a hook portion at said one end of the pole, said hook portion being slid able in a first guide in said one end longitudinally cf the pole and being normally urged resiliently and lonsitudinally outwards therefrom ready to receive part of a said cable clamp to be hung cn the hook portion and there being a second guide in said one end of the pole, said second guide intersecting said first guide and being for receiving said part of a said cable clamp when it is engaged by said engaging means, the arrangement being such that, in use, said hook portion can be drawn against its resilient bias by said operating means into said first guide whilst drawing with it said part of said cable clamp thereby trapping in substantially non-rotatable fashion said part in said second guide.

8. A pole according to claim 7, wherein said first guide is open-fronted to allow for passage oe the free end of said hook portion inside said pole.

9. A pole according to claim 7 or 8, wherein said means for operating said cable clamp engaging means is in the form of a slid able sleeve mounted about the pole remote from said cable clamp engaging means, said sleeve being coupled to an operating rod inside said pole and said operating rod being joined to said cable clamp engaging means, which is thereby operable by said operating means.

10. An electrical linesman's operating pole, substantially as hereinbefore described with reference to the accompanying drawings.

11. An electrical linesman's operating pole according to any one of the preceding claims in combinatIon with a cable clamp for attachment to and detachment from an overhead power supply line, said cable clamp including a ring, which constitutes said part of said cable clamp.

12. A combination according to claim 11, wherein said cable clamp further includes a downlead and an overhead power supply line engaging hook portion, said ring forming part of a threaded clamping means which can be screwed up by rotating said pole when engaged with the clamp to clamp a supply line in good electrical contact in said hook portion.

13. A combination according to claim 11 or 12, substantially as hereinbefore described with reference to Figures 3 to 5 of the accompanying drawings.