SUBSTANTIALLY CYLINDRICAL ELONGATE MEMBER

The present invention relates to a support apparatus for supporting a substantially cylindrical elongate member and relates particularly, but not exclusively, to a support apparatus for a cable.

The use of support apparatus for holding electrical cables, in particular very thick cables for handling high currents, is well known. The apparatus, referred to as a cable cleat, are typically formed as a pair of half cleats from a plastic material. Such cleats can also be used for much smaller cables that handle lower currents.

An example of a cleat of the prior art is explained with the help of figure 1 which shows a cleat half 10 which has a cable engaging surface 12. A pair of cleat halves 10 are used together to clamp around a cable of approximately radius R ₁₄ . Surface 12 also has a radius Ri and the centre of rotation of radius R ₁₄ , at point 16 is offset below the bottom surface 18 by a distance L ₂ o- As a result, when two cleat halves 10 are brought together around a cable of radius R ₁ , and a pair of nut and bolts (not shown) that extend through apertures 22 are used to mount the two cleat halves together, a gap of twice distance L ₂ o remains.

Because of this gap it is therefore possible to use the cable cleat with the cable of a radius smaller than radius Ri ₄ . However, if a cable of smaller radius is used then the portion of the engaging surface 12 that is in contact with the external surface of the cable decreases and remains only in the central portion of surface 12 indicated approximately at 24. As the area of internal surface 12 that is contacted by the cable decreases the grip that the cleat can apply to the cable also decreases. This is demonstrated in Figures 1d and 1 e. In Figure 1e a large cable, the maximum size suitable for this cleat, is being held. Contact between the cleat and the cable is made around 310° of the circumference of the cable, thereby providing excellent grip. In contrast, and as demonstrated in Figure 1d, when a small cable is griped by the cable only 76° of the circumference are being contacted leaving the vast majority (284°) not in contact with the cleat. As a result, the cleat is not safely holding the cable and can fail a puil test. In order to compensate for this it can be the case that a person connecting a cleat to a cable will tighten the clamping nut and bolt very tight so as to partially deform the cable and/or the cieat half to increase the surface area in engagement. Although this increases the grip on the cable this deformation can lead to damage of the cable and/or cleat half.

A further limit to the ranges of sizes of cables that can be carried by the cleat is when the two surfaces 18 engage with each other before sufficient pressure is applied to the cable. Because the above described problems each cleat can only properly hold a limited range of cable sizes which means that cleats must be made in many sizes to accommodate various cables sizes. This increases cost of production and creates storage problems with many sizes of cleats being kept to accommodate multiple cables sizes.

Preferred embodiments of the present invention seek to overcome the above described disadvantages of the prior art. According to an aspect of the present invention there is provided a device for use in a support apparatus for a substantially cylindrical elongate member, the device comprising:- a body having at least one engaging surface adapted to engage a surface of a substantially cylindrical elongate member, at least one said engaging surface having at least one first surface portion adapted to engage a portion of a surface of a substantially cylindrical elongate member of a first diameter and having at least one second surface portion adapted to engage a portion of a surface of a substantially cylindrical elongate member of a second diameter different from said first diameter; and clamp receiving means for receiving clamping means, the clamping means adapted to apply a clamping force to the substantially cylindrical elongate member between said engaging surface of said body and another surface thereby supporting the substantially cylindrical elongate member.

By providing a cleat half with a body that has an engaging surface with at least two portions one portion being able to engage a surface of the cable of the first diameter and a second portion adapted to engage a cable of a second diameter, the advantage is provided that the cleat can be used to properly grip cables of a wide variety of sizes, without risking damage to the cleat or the cable it is supporting. This therefore reduces the number of cleat sizes that must be produced to successfully grip a range of cable diameters. This in turn reduces production and storage costs. In a preferred embodiment the first surface portion is adapted to engage a substantiaily cylindrical elongate member of a smaller diameter than the diameter of a substantially cylindrical elongate member that said second surface portion is adapted to engage. In another preferred embodiment on a cross-section of said engaging surface, taken perpendicular to an axial direction of the elongate member when the device is in use, said first surface portion is adjacent the centre of said cross-section and said second surface portion is adjacent ends of said cross-section. This provides the advantage that a large cable is clamped by engagement with four surface portions towards the outside of the engaging surface and for a smaii radius cable it is clamped at two larger surface portions.

In a preferred embodiment the cross-section is formed from portions of a plurality of shapes wherein at least two shapes have different major dimensions and different centres of rotation. By having the cross-section formed from a plurality of shapes with different centres of rotation, particularly circles, the advantage is provided that the circles of the cross-section of the interna! surface can very closely engage a cable of two different diameters. This means that the cleat can very firmly hold and support these two types of cable. For cables with a diameter between the largest and smallest diameters the cable is held with sufficient grip to also pass normal pull tests.

In a preferred embodiment the shapes are joined by a plurality of smoothing connecting surface that are preferably substantially planar surfaces.

By connecting the shapes with planar surfaces, the advantage is provided that cables of a diameter between the largest and the smallest the cleat is designed for are firmly held.

In another preferred embodiment the first and second shapes are circles respectively having first and second diameters and first and second centres of rotation and said first diameter is smaller than said second diameter and said first centre of rotation is closer to said engaging surface than said second centre of rotation.

By using circles of different diameters with offset centres of rotation provides the best clamping for cables of different diameters, including cables in the range between the maximum and minimum diameters.

According to another aspect of the present invention there is provided a support apparatus for supporting a substantially cylindrical elongate member, the apparatus comprising:- a first device substantially as described above; and clamping means for clamping a substantially cylindrical elongate member between said first device and another surface.

In a preferred embodiment the other surface is an engaging surface of a second device substantially as described above.

In another preferred embodiment the clamping means comprises a bolt adapted to extend through an aperture in said first device and an aperture in said other surface and a nut.

According to another aspect of the present invention there is provided a device for use in a support apparatus for a substantially cylindrical elongate member, the device comprising:- a body having at least one engaging surface adapted to engage a surface of a substantially cylindrical elongate member and having at least one recess portion formed in said engaging surface, said recess portion adapted to receive at least one compressible gripping member, wherein said gripping member is adapted to be compressed as a result of engagement with part of a further device thereby in use expanding in the direction of said cylindrical elongate member and applying a gripping force thereto; and clamp receiving means for receiving clamping means, the clamping means adapted to apply a clamping force to the substantially cylindrical elongate member between said engaging surface of said body and another surface thereby supporting the substantially cylindrical elongate member.

By providing recessed portions in the engaging surface, into which compressible gripping members are inserted, provides the advantage that a pair of devices acting together can compress the gripping members causing them expand radially inwards. This in turn provides a gripping force on a cable and allows the cleat to be used over a greater range of cables with a greater range of diameters. The device may further comprise the gripping member.

In a preferred embodiment the recess portion has a curved surface running substantially parallel to said engaging surface.

The device may further comprise at least one support member adapted to support said gripping member and substantially prevent said gripping member expanding in a direction away from said cylindrical elongate member.

The support member ensures that the radial expansion of the gripping member acts inwards creating the maximum amount of grip on to the cable.

The device may also further comprise a support receiving recess adapted to receive a support member of another cooperating device.

In a preferred embodiment the gripping member is longer in length than the recess portion it is adapted to be received in. In another preferred embodiment at least one said engaging surface has at least one first surface portion adapted to engage a portion of a surface of a substantially cylindrical elongate member of a first diameter and having at least one second surface portion adapted to engage a portion of a surface of a substantially cylindrical elongate member of a second diameter different from said first diameter.

According to a further aspect of the present invention there is provided a support apparatus for supporting a substantially cylindrical elongate member, the apparatus comprising:- a first device according as set out above; and clamping means for clamping a substantially cylindrical elongate member between said first device and another surface.

In a preferred embodiment the clamping means comprises a bolt adapted to extend through an aperture in said first device and an aperture in said other surface and a nut.

Preferred embodiments of the present invention will now be described, by way of example only, and not in any limitative sense, with reference to the accompanying drawings in which :-

Figures 1a, 1 b and 1c are respectively perspective, side and bottom views of a half cleat of a cable cleat of the prior art; Figures 1d and e are end views of the prior art cable cleat of Figures 1 a, 1b and 1c in use with respectively small and large cables passing therethrough;

Figure 2 is a perspective view of a cleat half of a support apparatus of the present invention;

Figures 3a, 3b and 3c are respectively front, bottom and side views of the cleat half of figure 2;

Figure 4 is a perspective sectional view of a portion of the cleat half of figure 2;

Figure 5 is a top view of the cleat half of figure 2;

Figure 6 is a sectional view of the cleat half of figure 2 along the line A-A;

Figures 7a, 7b, 7c, 7d and 7e are sectional and end views showing a cleat formed from two of the cleat halves of figure 2 in use with cables of different diameter; Figures 8a, 8b and 8c are respectively front, bottom and side views of a cleat half of another embodiment of the present invention;

Figure 9 is a top plan view of the cleat half of figure 8;

Figure 10 is a sectional view of the cleat half of figure 9 along the line B-B;

Figures 1 a, 11 b and 11c are end, plan and front views of a cleat half of a further embodiment of the present invention;

Figure 12 is a sectional view along the line C-C if the cleat half of Figure 11 ;

Figure 13 is a sectional view along the line D-D if the cleat half of Figure 11 ; Figure 14 is a perspective view of the cleat half of Figure 11 ;

Figure 15 is a perspective view of a cleat half of another aspect of the present invention; Figure 16 is a side view of the cleat half of Figure 15; Figure 17 is a sectional view along the line D-D; Figure 18 is a plan view of the cleat half of Figure 15;

Figure 19 is a perspective view of a pair of cleat halves of Figure 15 clamping a portion of a cable;

Figure 20 is a side view of the cleat halves of Figure 19;

Figure 21 is a sectional view along the line E-E; and Figure 22 is a sectional view equivalent to that in Figure 21 but with the cleat halves clamping a larger cable.

Referring to figures 2 to 7, a device hereinafter referred to as a cleat half 100 is used in a support apparatus or cleat 102 for supporting a substantially cylindrical elongate member which could for example be a cable 104. Cleat half 100 has a body 106 that has an engaging surface 108 for engaging the external surface 110 of a sheath of cable 04. As shown in figure 4 the engaging surface 108 could be formed with a plurality of ribs 12 thereby forming a plurality of engaging surfaces 114.

The engaging surface 108 has a first surface portion 6 that is adapted to engage the external surface 110 of a cable 104 having a first diameter. This first and smallest diameter of cable is shown in figure 7a. The engaging surface 108 also has second surface portions 118 that are adapted to engage the external surface 1 0 of a cable 104 of a second diameter. In this example the second diameter is a larger diameter cable shown in figure 7c.

The cleat half 100 also has clamp receiving means in the form of apertures 120 that receive clamping means in the form of threaded bolts 122 that receive nuts (not shown) that apply a clamping force between the two cleat halves 100 thereby forming a whole cable cleat 102 which supports the cable 04.

Referring particularly to figures 6 and 3a when a cross-section is taken through the cleat half 00 along a line (indicated at A-A in figure 5) that is perpendicular to the axis 124 of cable 104, the engaging surface 08 has a shape formed from two shapes. In this example the two shapes are circles that have different major dimensions, in the case of circies different diameters, and different centres of rotation. The first of these shapes produces first surface portion 116 and is a circle having a radius R126 and a centre of rotation 128. The second surface portions 118 are formed from a circle of radius Ri ₃₀ that has a centre of rotation 132. The centre of rotation 128 is aligned with a bottom surface 134 of cleat half 100. One side of cleat half 100 has a guard portion 136 that when two cleat halves are used together covers a gap 138 that may be present between the two bottom surfaces 134. The centres of rotation 128 and 132 are separated by a length L140. The junction between the first and second surface portions 116 and 1 18 is smoothed with planar portions 142 (linear sections in cross-section) that are set at an angle Θ relative to the bottom surface 134.

Referring to figure 7a, a cleat 102 is shown in use with a cable of diameter Di _44l this being the smallest cable suitable for use with this cieat. The diameter Di ₄ is equal to twice the radius R126 and when two cleat halves are placed together around the cable 104 and clamped together by nuts attached to bolts 122) the axis 124 is aligned with centre of rotation 128. Because the circle forming radius R126 matches {that is half of) the diameter Du4 when the cleat 102 is in use with this cable, the external surface 1 10 of cable 104 sits in engagement with first surface portion 116 of engaging surface 108 as can be seen in figure 7a. This provides a large surface area of engagement allowing the cable 104 to be firmly held by the cleat 102. As can be seen in figure 7a the bottom surfaces 134 of cleat halves 100 come into engagement with each other. Referring to figure 7c, the cleat 102 is used with the largest suitable cable that it is designed for, this cable 104 having a diameter D ₄₈ . This diameter Di ₄₈ is twice the radius R ₁₃₀ and the axis 124 of cable 104 is aligned with centre of rotation 132. As a result of the matching of diameter D ₈ with radius R130 the external surface 1 10 of cable 104 is engaged by second surface portions 1 18 of engaging surface 108 which also provides a large area of surface engagement.

Referring to figure 7b a cable of diameter D ₁₄₆ that is larger than diameter D ₁₄₄ but smaller than diameter Di ₄₈ can also be used with cleat 102. In this instance the diameter D-| ₄₆ does not match radius R-i26 or i3o and when in use the axis 124 will lie between centres of rotation 128 and 132. As a result, the cable 104 does not sit entirely within first surface portion 1 16 or second surface portion 118 but sits partially in engagement with planar portions 142 and parts of first and second surface portions 16 and 118. A cleat half is typically made from nylon or polypropylene and a cable sheath is typically formed from PVC. The slight flexibility of these materials allows sufficient engagement between a cable 104 of diameter Di ₄₆ and the engaging surface 108 of cleat half 100. The use of planar portions 142, as well as improving the gripping surface are of each cleat half on the cable, prevents the engaging surface 108 at the junction between the two curved portions from digging into the cable and potentially damaging the sheath or the cables inside. It should be noted that the portions 142 could be other shapes than planar. For example, any smoothing curve or blended arc that joins the first and second surface portions 116 and 118 will act to prevent the junctions between the surface portions 116 and 118 from digging into the cable and to improve the grip of the cleat on intermediate sized cables by increasing the angle of contact around the cable circumference. Figures 7d and 7e in addition show the angles of the circumference through which the cleat is in contact with the cable. Figure 7d, showing the cleat and smallest cable equivalent to Figure 7a, shows that the pair of cleat halves are in contact with the cable around 196 ^° of the cable's circumference. Figure 7e, showing the cleat and largest cable equivalent to Figure 7c, then shows that the cleat is in contact with the cable around 158° of the cable's circumference. The cieat of the present invention therefore sacrifices a small amount of surface contact, and therefore grip, on the largest cable to increase the surface contact on the smallest cable. It can therefore be seen that the cleat 102 of the present invention is able to properly grip a range of cables of different diameters. This reduces the number of cleat sizes that must be produced to successfully grip a range of cable diameters.

Referring to figures 8, 9 and 10, in which parts in common with figures 2 to 7 have been labelled with like reference numerals increased by 100, these figures show an alternative embodiment of the present invention which similarly utilises an engaging surface 208 shaped from two circles of differing diameters with offset centres of rotation.

Referring to figures 11 a, 11 b, 11c, 12, 13 and 14, in which parts in common with figures 2 to 7 have been labelled with like reference numerals increased by 200, these figures show an alternative embodiment of the present invention. This embodiment similarly utilises an engaging surface 308 shaped from two circles of differing diameters with offset centres of rotation. The main difference from the embodiment shown in Figures 2 to 7 is the use of a single fixing bolt (not shown) that extends through aperture 320. Also the guard portion (136 in Figures 2 to 7) is replaced with a pair of half guards 350 and 352 that cooperate with their equivalents on the other cleat half they are teamed with to cover the gap 338.

Referring to figures 15 to 21 , in which parts in common with figures 2 to 7 have been labelled with like reference numerals increased by 300, these figures show a further alternative embodiment of the present invention and another aspect of the present invention. This embodiment is specifically designed for use with larger cables but is applicable to any size of cable and further extends the range of cable diameters over which the cieat can work.

Cable cleat 402 is formed from two half cleats 400 and operates in the same manner as the previous embodiments. However, cleat 402 has at least one, and preferably two spaced apart, recess portions 460 that receive a respective compressible member or insert 462 that is typically formed from a rubberised material such as Thermoplastic elastomer (also known as TPE or thermoplastic rubber) or a silicone based soft rubber. The inserts are sized to extend beyond the ends of recess portions 460 when the first placed into cleat half 400. That is, from the ends 464 of insert 462 that are closest to the portion of surface 408 that has the smallest radius 416, to the other ends 466 of insert 462 is longer than the recess 460 and therefore the inserts 462 extend beyond the bottom surface 434. The inserts 462 are curved with a convex surface 468 shaped to follow the shape of the recess portion 460 and a concave surface 470 shaped to follow the curve 418 of engaging surface 408.

Cleat half 400 also has a support member 472 and a support receiving portion in the form of a support aperture 474 that receives a support member of another cleat half. The purpose of the support member 472 is to extend the recess 460 so as to support the insert 462 along it whole length. The support aperture 474 allows opposing cleat halves 400 to engage with each other without the support members 472 preventing the cleat halves from moving through their full range of sizes of cable.

Referring in particular to figure 22, when a cleat of the present invention is used on a cable of large diameter, the gap between the bottom surfaces 434 is large and end surfaces 466 of insert 462 are just in engagement with each other. As a result, there is no compression of inserts 462 and they remain at their original thickness. The inserts 462 engage the cable 404 because they are sufficiently thick to be pressed into engagement with the cable 404 and the rear surface of recess 460 and thereby contribute to the gripping force applied to the cable.

Referring now to figure 21 , when a cleat of the present invention is used on a cable of smaller diameter the gap between the bottom surfaces 434 is much smaller. This causes the end surfaces 466 of inserts 462 to be pressed into engagement with each other. Since the other ends 464 of inserts 462 are pressed into engagement with the ends of recess 460 the inserts are forced to expand radially. The presence of the support members 472 prevents radially outward expansion causing the inward expansion of the insert 462. This in turn causes the inner, concave surface 470 to become pressed into engagement with the cable 404 thereby apply a gripping force around more of the circumference of the cable 404. With reference also to figures 7d and 7e, as described above, when inserts 462 are added to this cable cleat, additional grip is provided around the cable thereby filling in some of the gaps left between the cleat halves. When the smallest cable is used (figure 7d) a gap of 164° was left around the cable. The inserts completely fill the gap, providing grip around 360° of the cable surface. When the largest cable is used (figure 7e) without inserts gaps that total 202 ^° are left with 158° of the circumference engaged by the cleat body. When the inserts 462 are added the grip increases by a further 60° (30° on each side of the cleat half at the gap) meaning that 218 ^° of the circumference is engaged by the cleat and inserts and a gap only remains at the first surface portion 116.

It should be noted that the recesses 460 and insert 462 would also work if used on cleats that do not have the variation in the curves of engaging surface 408. This aspect of the present invention could be equally used by including recesses and insert of the type described above in a cleat of the prior art such as that shown in figures 1a to 1e. When used in this type of cleat the inserts 462 would engage around 360° of the surface of the cable for all cables sizes that the cleat was designed to work with.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention which is defined by the appended claims. For example, a cleat of this type could be used with any substantially cylindrical elongate object including, but not limited to, pipes and tubes of various materials. Also, the shapes used in the described embodiments, the circles with radii R ₂ e and R-130, could be replaced with other shapes. For example, these circles could be replaced with substantially regular polygons with large numbers of sides that closely approximate to circles such as decagons or dodecagons. These shapes would be effective with cables of circular cross-section or with cables with similar polygenic cross-section. Furthermore, the cleat half 100 or 200 could be used with another surface that engages the other side of the external surface of the cable. For example, the cleat half could be used to press the cable against a planar surface such as a wall.