This invention relates to cable cleats for mounting one or more cables or the like to a support, and particularly to "trefoil" cleats for mounting high voltage electric cables.

In order safely, efficiently and neatly to mount a cable or cables to a support such as a wall by means of a cleat it is generally important that the cleat should engage tightly around the cable(s) to hold the cable(s) securely. This is particularly necessary in the case of high voltage electric cables where a short circuit may result in very large stresses on the cleat due to repulsive forces between cables.

One form of cleat is a "trefoil" cleat which is traditionally formed of three elongate members or limbs interconnected in a generally triangular configuration. It is known to provide such a cleat in which one of the limbs serves as a base which in use is bolted to a support, the remaining two limbs being hinged or bolted to the base limb and bolted to each other at the apex of the triangle. A disadvantage of such a cleat is that it can only accommodate cables having a specific nominal diameter or a diameter which differs only very slightly from the nominal diameter. This is inconvenient and costly since a large range of cleats of different sizes is necessary to accommodate the different sizes of cable in common use. Furthermore, such cleats can be relatively awkward to mount.

In addition to such trefoil cleats it is also known to provide other cleats of split ring-like configuration, the ends of the ring being bolted together so that slightly differing cable sizes can be accommodated by tightening the bolt or bolts to a varying degree. Cleats having a range taking facility

are also known in which a metal strap is wound around one or more cables and is tightened about the cable(s) to a desired tension. However, neither of these forms of cleat is entirely satisfactory since, for example, they may not be easy to mount or adjust and may not be well adapted to mount high voltage electric cables.

According to the present invention there is provided a cleat for mounting one or more cables or the like to a support comprising three or more elongate members, each member having a central cable or the like support portion and first and second angled end portions respectively at opposite ends of said member; said members being connectable, in use, first end portion of one member to second end portion of an adjacent member, to from a polygonal structure encircling said one or more cables or the like, said first and second end portions of said members being such as to provide for relative sliding engagement therebetween at said connections between members so as to permit said polygonal structure to expand or contract whilst maintaining the same shape, and locking means for locking each said connection between first and second end portions of said members at a selected relative position of sliding engagement therebetween. There is thus provided a cleat which by virtue of the adjustment between members is suitable to mount a range of cable sizes. A very limited number of cleat sizes can then accommodate a wide range of cable sizes with consequent cost savings and increased convenience to the user. The connections between members and the associated locking means may be such as to permit captive interconnections to be made between one or more members in the expanded state of said connections i.e. before the cleat is fully assembled, contracted about the cable and locked in the contracted state. This facilitates the presentation of the cable(s) to a partially assembled mounted cleat, the completion of the

assembly of the cleat about the cables and its final tightening by contraction and locking about the cable(s) .

Such an arrangement may be made sufficiently strong so that, if a plurality of high voltage electric cables are mounted, substantial outward stresses on the cleat can be resisted in the event of a short circuit.

The members of the cleat may be substantially identical in length so that the connections between adjacent members are substantially uniformly circumferentially spaced around the cleat and the members define a regular polygonal structure which is maintained as the cleat is radially expanded or contracted. Whilst a cleat according to the invention may be formed of more than three members, for example, four or five, a preferred construction comprises three members adapted to be assembled in a generally triangular configuration i.e. as a trefoil cleat. Such an arrangement may be particularly simple and effective, being convenient to mount and adjust, strong and economic to manufacture.

The connection between the first and second angled end portions of the members may take various forms e.g. overlying tongues. In a particularly convenient arrangement one end portion is in the form of a tongue or tongues and the second end portion is in the form of a socket or groove or channel within which the tongue or tongues is/are slidable. Alternatively, the connection may be such as to allow one member serving as a closure member to pivot relative to its neighbour so that the cleat can be opened and/or closed to facilitate insertion and/or removal of the cables by swinging the closure member outwardly from a closed position in which it is connected to an adjacent member at both ends to an open position in which the connection at one end is released.

Such an arrangement is convenient to use since all the members may be captively interconnected before the cables are inserted, with the closure member in an open position in which it does not obstruct the insertion of cables into the cleat, and once the cables are inserted the closure member may then be pivoted about its second end into a closed position and the cleat contracted about the cables. The cleat can be opened and closed again at any subsequent time as desired by releasing the connection at the first end of the closure member. In one arrangement the second end of a closure member and the first end of an adjacent member are in the form of overlying angled tongues between which a captive pivotal interconnection may be made. The first end portion of the closure member and second end portion of the other adjacent member are configured so that the connection can easily be released and so as to permit pivotal opening of the closure member, and in one arrangement these end portions also comprise overlying tongues. Side flanges may be provided at other connections formed between overlying tongues to provide rigidity.

The locking means may take various forms, for example, bolts, grub screws, friction means, interlocking projections and recesses or a combination of two or more such means.

In one arrangement bolts extend between adjacent members in the direction of sliding adjustment therebetween, the bolts being accommodated within the sliding end portions for compactness. However, in a preferred embodiment in which the locking means comprises bolts, said bolts extend at right angles to the direction of sliding adjustment of said first and second end portions, each engaging with a nut or internal thread formed in one end portion and an aperture in the other of said first and second end portions in the form of an elongate slot with closed

ends in which the bolt can slide and which defines the limits of adjustment. Preferably there is either a thread formed in one portion or a nut or bolt is captive in one or other of the end portions. Another form of locking means comprises interlocking projections in the form of opposing rows of teeth formed on the engagement surfaces of adjacent angled portions, and which are arranged to interlock to resist expansion of the cleat. Such may comprise the sole locking means, or may be used in combination with a second locking means such as bolts to provide greater strength to resist expansion of the cleat e.g. under short circuit conditions. The arrangement may be such that the opposing rows of teeth interlock or are biased towards each other sufficiently to resist expansion by virtue of the configuration of the end portions, or alternatively or additionally where a second locking means is provided in combination with opposing rows of teeth, the second locking means will preferably act when tightened to bias the opposing rows of teeth towards each other.

The interlocking teeth may be configured so that adjacent members may be engaged relatively easily to assemble and contract the cleat, but substantial resistance is encountered to expansion or disassembly of the cleat. The teeth may extend across all or only a portion of the engagement surfaces.

In one arrangement in which a tongue of a first end portion of a member is provided with teeth which are adapted to interlock with teeth of the second end portion of an adjacent member, the tongue is resilient and is configured to be biased into engagement with the teeth of the second end portion, but may be manually deflected to allow expansion or disassembly of the cleat. Locking means, such as interlocking teeth may also provide rigidity to the cleat.

As discussed above, the cleat may be manually

contracted around the cables, adjusted according to the diameter of the cables and locked such that the cables are held tightly as a snug fit therein. However, under some circumstances it may be desirable to exert greater pressure on the cables to compress them than can be provided by manually contracting the cleat, and in one arrangement there is provided further means for tensioning the cleat about the cables. Said tensioning means may comprise one or more bolts extending between adjacent members and in one arrangement there is provided a bolt extending between two members adjacent a sliding connection therebetween, in a direction substantially parallel to the direction of sliding engagement. The bolt(s) can be tightened to contract the cleat about the cables whereby to compress them. The members of the cleat may be substantially identical in the form of said first and second end portions and locking means and thus as regards assembly of the cleat be interchangeable. Generally however only one member need be provided with fixing means eg an aperture or apertures, whereby it may be mounted to a support eg a wall, but nonetheless for manufacturing convenience all members may be identical in this respect. Alternatively the members of the cleat need not be identical, for example, the shape of one or more members may be modified to facilitate mounting to a support. A member to be mounted to a support may have apertures for mounting bolts and may have a relatively large depth or be provided with means for spacing the cleat from the support. Furthermore, the limbs may not be identical if one of the connections is arranged to facilitate relative pivotal motion between end portions and there may be other reasons why it is preferable for the limbs to have different forms. For some applications the supporting surfaces of the centre portions of the members may need to be differently contoured according to the number and arrangement of

cables or the like to be mounted.

The support surfaces of the centre portions of the members may be flat or they may be contoured, for example having concave grooves to fit around the cable(s) or the like. Preferably the members are adapted to mount detachable support pads which may have flat or contoured support surfaces. Different such pads may be then attached to the members to accommodate different numbers or sizes of cable(s) or the like. Furthermore such pads may be of varying height according to the diameter of the cable(s) or the like to be mounted, to further increase the range taking capacity of the cleat. Pads may be removable to facilitate access to means such as a bolt for mounting a member to a support.

Various numbers of cables may be supported, for example one, two, three or four. A trefoil cleat may be particularly well adapted to mount one, three, a multiple of three cables or any other number of cables which are conveniently assembled in a triangular arrangement.

Cleats according to the invention may be formed of any suitable material such as injection moulded glass reinforced nylon, die cast aluminium, steel or other metal or plastics materials. An advantage with plastics materials is that they can be relatively lightweight and easily manufactured by injection moulding. However, metals such as steel may provide greater strength than can be achieved by plastics injection moulding and may therefore be better adapted to withstand high forces on the cleat such as may occur under short-circuit conditions. Furthermore, metals tend to be flame resistant whereas suitably strong plastics materials may not be. In one arrangement a metal frame is used in combination with support pads made from a flame retardant plastics material such as polypropylene. Some plastics materials such as polypropylene may not have

suitable properties e.g. sufficient strength to form a cleat, whereas they may be well adapted to form support pads e.g. by virtue of being flame retardant, in a cleat formed largely of a different material such as a metal. A number of embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings wherein:-

Figure l shows an end view of a contracted cable cleat comprising three interconnected members or limbs according to a first embodiment;

Figure 2 shows an end view of the cleat of Figure 1 when expanded;

Figures 3a, b & c respectively show a side view, a top view and an end view of a limb of the cleat of Fig 1;

Figure 4 shows a perspective view of a cable support pad adapted for attachment to the limb of Fig 3 and radiused for cleating 3 cables;

Figure 5 shows a side view of a cleat limb according to a second embodiment;

Figure 6 shows a perspective view of one end of the member of Figure 5.

Figures 7 and 7a show a side view and a perspective view of one end of a limb according to a third embodiment;

Figures 8a, b and c show a side view, an end view and a view from above of a limb according to a fourth embodiment;

Figures 9a and b show a persepective view and a view from below of a support pad adapted for attachment to the limb of Fig. 8;

Figure 10 shows an end view of another embodiment of cable cleat;

Figures 11a and b show views from below of two limbs forming the cleat of Figure 10; and

Figures 12a and b show a perspective view and an end view of a support pad for use with the embodiment of

Fig. 10.

Figures 1, 2 and 3 show a cable cleat, designated generally 1, comprising three members or limbs 2,3 and 4 mounting three cables (shown dotted in Figure 1 and omitted from Figure 2) to a supporting wall 5. The cleat 1 has a generally triangular configuration. Each limb 2,3,4 is elongate having a central support portion 6 and a first and second angled end portion 7 and 8 as shown in greater detail in Figure 3. The limbs 2,3 and 4 are substantially identical and form a regular substantially triangular structure. The first angled end portion 7 forms a tongue provided with an aperture 9 extending transversely therethrough in which a captive nut 9a is received. A 'U ¹ shaped channel section constitutes the second angled end portion 8 and is dimensioned snugly to receive the tongue 7 therein. In use the three limbs are assembled end to end into a triangle as shown in Figs 1 and 2, with the tongue forming the first end portion 7 of one limb slidably engaged in the channel forming the second end portion 8 of the adjacent limb.

Figure 1 shows the cable cleat 1 in a contracted configuration, with each tongue fully received within the adjacent channel. Figure 2 shows the same cleat fully expanded with each tongue only partly received in the adjacent channel.

Locking means are provided by bolts 9b (one shown in Fig. 2) which extend through slots 10 in the bases of channels 8 to engage with captive nuts 9a _. accommodated within apertures 9. Apertures 9 and slots 10 are formed in the end portions 7,8 of all three limbs, but for convenience, are shown dotted on only one pair of ends 7,8 in Figures 1 and 2 as are nut and bolt 9a, 9b. The cleat is mounted to the wall 5 by means of a bolt (not shown) extending through an aperture 11 in the central portion 6 of the limb 2 adjacent the wall. An

10 aperture 11 need not be provided in each of the other limbs 3 and 4.

The limbs are provided with detachable cable supporting pads 12, 13 and 14 shown in Figure 1 (not shown in Figure 2) , and in detail in Figure 4. Each pad is contoured on its inward facing surface with two transversely extending concave grooves 15,16 to engage the cables (shown dotted in Figure 1) . The illustrated pads 12, 13, 14 could be replaced, for example, with support pads contoured with a single transversely extending concave groove for cleating a single cable. Alternatively, pads having a flat inward facing surface may be adopted for multi purpose use. A rectangular projection 17 on the outer face of each pad 12,13,14 makes an interference fit within a rectangular recess 18 formed in the inward facing face of each limb 2,3,4.

In use limb 2 and lower limb 3 may first be assembled and locked relative to each other in a position which corresponds approximately to their intended final relative position, pad 12 being initially detached from limb 2. The partly assembled cleat may then be bolted to wall 5 and the pad 12 may be fitted to limb 2. The cables may be laid in the generally 'V* shaped recess formed between the two assembled limbs 2,3. The upper limb 4 may then be engaged with limbs 2 and 3 and slid into an approximate final position, the end portions 7,8 of limb 4 sliding relative to the adjacent end portions of limbs 2 and 3. If necessary as a final adjustment, the limbs may then be moved together such that each tongue forming a first end portion 7 slides in each channel of an adjacent second end portion 8, whereby the cleat is contracted radially about the cable to a position such as is shown in Figure 1. To maintain the geometry of the cleat it is preferable to slide the limbs together simultaneously, or to slide each with respect to its neighbour by a small amount in turn. At any point the limbs may be locked in their

11 relative positions by means of the bolts 9b extending through slots 10 and engaging with nuts 9a in apertures 9. The final position will be selected depending on-the diameter(s) of the cable(s) . To disassemble the cleat the limbs are unlocked and pulled apart.

To accommodate a different number of cables, or to increase the range taking capacity, different pads 12,13,14 having different contours or heights may be used. Removal of pad 12 allows access to the bolt (not shown) securing the cleat to the wall 5.

A further form of limb 20 of a second embodiment of the invention is shown in Figure 5. The limb comprises a central portion 26 and first and second angled end portions 27 and 28. The first end portion 27 is formed as a split tongue 30 and the second end portion 28 comprises a socket 31 of rectangular cross-section. The split tongue 30 has two resilient legs 32,33 on the outer of which 32 is formed a row of outwardly facing teeth 34. A flange 35 extends alongside the teeth 34 as shown in Figure 6. The socket 31 is provided on its inwardly facing surface with a complementary row of teeth 36 and a port 37 in the side wall of the rectangular section allows access to the flange 35 when tongue 30 is disposed within socket 31. In use the three limbs 20 are assembled end to end in the manner depicted in Figures 1 and 2 with respect to the first embodiment. Each tongue 30 on one limb is slidingly engaged within the socket 31 formed in the adjacent limb. The teeth 34,36 are configured such that having regard to the resilience of tongue 30 they can easily be slid over each other as the limbs are moved towards each other to contract the cleat, but prevent withdrawal in the opposite direction to expand the cleat. Thus the interlocking of the teeth locks the limbs against outward forces such as might be experienced in the event of a short circuit between high voltage electric cables. In order to expand the cleat

if desired, the resilient outer leg 32 of the split tongue 30 can be deflected away from the teeth 36 by pressure applied to flange 35 by a tool extending through port 37 to allow the teeth to pass over each other.

In other aspects the second embodiment made up of limbs 20 as shown in Figure 5 functions in a similar manner to the first embodiment.

Fig. 7 shows another form of limb 30 which is similar to the limb of Figs. 5 and 6 and in which similar parts are represented by the same reference numerals. In this embodiment the tongue 30 has sufficient resilience to enable it to be levered away from the teeth 36 in the corresponding socket 31 without requiring it to have a split form. Furthermore, the port 37 in the side wall of the socket is extended in the direction of sliding engagement to allow leverage to be applied to the angled portion at the end of the tongue at whatever depth the tongue is inserted into the socket. A further difference between the limbs of Figs. 5 and 7 is that in the limb 30 of Fig. 7 the teeth only extend part of the way across the width of the tongue as shown in Fig. 7(a) and across a corresponding part of the socket at the side closest to port 37. Therefore only that part of the tongue closest to the point where the leverage is applied has teeth in engagement with correspondingly located teeth in the socket. This makes it easier to manually lever the teeth apart sufficiently to expand the cleat when desired. Fig. 8 shows a limb 40 of a fourth embodiment which is similar to the embodiment of Figs. 1 to 3, (and in which similar parts are indicated by the same reference numbers) except that opposing sets of teeth 41,42 are provided facing outwardly on the tongue 7 and inwardly on the channel section 8. The cleat 40 is assembled in the same way as the cleat 1 of Figs. 1 to 3, and is contracted by sliding each limb in turn by a small

amount e.g. over the length of one tooth, with respect to its neighbour. As the bolts (not shown) passing through apertures 9 and slots 10 are tightened the teeth 41,42 are biased towards each other. A greater resistance to forces tending to expand the cleat is therefore provided by the combination of the bolt means and the interlocking teeth in this embodiment than are provided in the first embodiment by the bolts alone.

Fig. 9 shows a support pad 43 for use with the limb 40 of Fig. 8. The support pad 43 is provided with four depending projections 44. The projections 44 are adapted to be received in use in a channel 45 defined in the central portion 6 of limb 40. The projections 44 are much narrower in a lateral direction across the width of the limb than in a longitudinal direction along the length of the limb and have some resilience to bending in a lateral direction. The projections are laterally spaced substantially by the width of channel 45 and are splayed outwardly by a small angle so as to form an interference fit in the channel. Inwardly projecting vertical ribs 46 in channel 45 locate the support pads in a longitudinal direction.

The embodiments of Figs. 1 to 9 are all formed of a suitable plastics material such as glass-reinforced nylon.

Fig. 10 shows an embodiment in which a cleat comprises three elongate members or limbs 52,53,54 which are formed of metal and have releasable flame-retardant polypropylene support pads 55 (Fig. 11) snap fitted to a central portion thereof for carrying three cables in a trefoil arrangement. The cleat is adapted to be mounted on a wall by means of screws (not shown) passing through apertures 56 in one of the three limbs 52. The cleat is spaced from a wall or other support surface by means of a spacer 57.

Each limb 52,53,54 has first and second end portions in the form of an angled tongue. Each angled

end portion is arranged to overlie the end portion of an adjacent limb and the engagement surfaces are provided with co-operating rows of interlocking teeth 58 so as to provide resistance against expansion of the cleat and to provide rigidity.

The first end portion 59,60,61 of each limb is provided with an elongate slot 62 and the second end portion 63,64,65 is provided with a corresponding threaded aperture 66. Captive interconnections can be made between the first end portion of one limb and the second end portion of the adjacent limb by means of a bolt (not shown) extending through an elongate slot 62 and threadedly engaging in the corresponding threaded aperture 66. In the fully assembled cleat the elongate slots permit sliding between adjacent members in the plane of the cleat, the direction of sliding between the end portions in adjacent connections being offset by approximately 60° such that as the cleat is expanded and contracted a substantially triangular shape is maintained. Once the cleat has been contracted around the cables to a desired configuration according to the size of the cables, the bolts extending through slots 62 and apertures 66 are tightened to lock the limbs in the desired configuration. The tightening of the bolts biases the opposing interlocking teeth at each connection towards each other so that substantial resistance is provided to the expansion of the cleat e.g. under short circuit conditions.

The first end portion 59 of limb 52 and the second end portion 65 of limb 53 are each angled along a line at 45° to the longitudinal axes of the respective central portions as indicated by the angle A in Figures 10a and b. The elongate slot 62 in the first end portion 59 is formed at an appropriate angle to the longitudinal axis through the end portion so that the cleat can be expanded and contracted as described whilst maintaining the same shape. The arrangement is such

that if a bolt (not shown) extending through slot 62 in limb 53 and aperture 66 in limb 52 is loosened and the bolt (not shown) connecting limb 53 to limb 54 is removed, limb 53 can be pivoted outwardly about the bolt connecting limbs 52 and 53 to open the cleat whilst captive interconnections between limbs 52 and 53 and between limbs 52 and 54 are maintained. The connection between limbs 53 and 54 is such as to allow pivotal opening of the closure member. This allows cables to be inserted into the partially assembled and open cleat without obstruction from the limb or closure member 53 which is then swung into a closed position wherein a connection is made between end portions 61 and 64. The bolt at the connection between limbs 53 and 54 can then be replaced and the cleat contracted and locked in a desired configuration.

Two apertures 67,68, one of which is threaded are formed in limbs 53 and 54 adjacent the connection therebetween. A bolt (not shown) extends through a first of said apertures and makes threaded engagement with the second, threaded aperture to provide means for compressing cables supported by the cleat. This bolt must be removed to allow the cleat to be opened.

The opposing rows of interlocking teeth on each end portion tend to prevent pivotal sliding of first and second end portions relative to each other when the limbs are locked together by means of the bolts (not shown) so as to bias the teeth towards each other. However it would also be possible to provide additional means such as side flanges at the connection between end portions 60 and 63 preventing relative pivotal motion therebetween optionally even when the bolts are loosened and thus providing even greater rigidity.

Although the invention has been specifically described in relation to the mounting of electric cables, it should be clearly understood that it could be applied to the mounting of like extended articles such

as, for example, ducts, pipes, rods, tubes or ropes.