GB2267605A

GB2267605A - Cable tray bridging members

Info

Publication number: GB2267605A
Application number: GB9211656A
Authority: GB
Inventors: Brian Roberts
Original assignee: ASSOCIATED PERFORATORS AND WEA
Current assignee: ASSOCIATED PERFORATORS AND WEA
Priority date: 1992-06-02
Filing date: 1992-06-02
Publication date: 1993-12-08
Anticipated expiration: 2012-06-02
Also published as: GB2267605B; GB9211656D0

Abstract

A cable tray bridging member comprises a one-piece metal pressing providing a base (10) upstanding side wall (15, 16, 17, 18) of double-walled form and extensions (19, 20; 25, 26) at the end of the side walls also of double-walled form for connecting the bridging member to adjacent cable trays. The extensions are formed with slots (29) for bolting to the side walls of adjacent cable trays and with spacer elements (28) between the walls of the extension to maintain the separation of the walls when clamped to the walls of the adjacent cable trays. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO CABLE TRAY BRIDGING MEMBERS This invention relates to cable tray bridging members for use in cable tray systems for supporting runs of electrical cables in buildings, tunnels and similar installations.

Cable trays comprise elongate shallow channel members in which electrical cables can be laid and special bridging members are provided at corners, intersections, cross-overs, risers, reducers and the like.

Conventionally, cable tray bridging members are formed from metal pressings and comprise a base and integral side walls having end extensions adapted for connecting the bridging member to the side walls of adjacent cable trays. The sides of the joining member may be of inverted U shaped cross section to increase stiffness whilst the extensions are of single wall form to provide flexibility for alignment with the sides of the cable tray to which the joining member is to be connected. The single wall form of the extensions reduces the strength of the joining member in that region thereby limiting the maximum carrying capacity of the joining members.

This invention provides a cable tray bridging member to link in a run of cable trays comprising a one piece metal pressing providing a base and upstanding sides of double-walled form, the sides having double-walled extensions at each end toprovide connection members for connecting the bridging member in a cable tray run.

Preferably the double walls including the end extensions of each side of the bridging member are spaced apart and spacer elements are provided between the walls of the extensions to maintain the separation of the walls when clamped to the walls of the adjacent cable trays.

More specifically the double-walled sides of the bridging member are of inverted U-shaped cross section each having an outer wall extending upwardly from the base of the bridging member to the base of the U and an inner wall extending downwardly from the base of the U and stopping short of the base of the bridging member.

According to a further feature the base of the U of each extension of the side may be cut away to facilitate flexing of the extension to align with the sides of the cable tray to which the joining member is to be secured.

In any of the above arrangements each side extension of the bridging member may be formed with an elongate slot extending lengthwise of the extension to receive bolts for securing the extension to the side walls of an adjacent cable tray.

The following is a description of a specific embodiment of the invention, reference being made to the accompanying drawings in which: Figure 1 is a perspective view of a cable tray bridging member for connecting two runs of cable trays extending at right angles to each other; Figure 2 is a plan view of part of the tray; Figure 3 is a section on the line 3-3 of Figure 2; and Figures 4 and 5 show a modified arrangement.

The bridging member illustrated in the drawing is formed from a one piece metal pressing and comprises a base plate 10 of elongate hexagonal shape as viewed in plan the elongate side edges of which are indicated at 11 and 12 and the shorter side edges of which are indicated at 13 and 14.

The side edges 11 and 13 of the hexagon form the outer periphery of the bridging member. The side edge 11 has an integral upstanding inverted U-section wall 15 the outer portion of which is formed integral with the base and the inner portion of which extends downwardly towards but stops short of the base. The side edges 13 have similar inverted U-section walls 16 and 17. The walls 15, 16 and 17 form the outer periphery of the bridging member with gaps 18 and 18a being provided between the walls 15 and 16 and 15 and 17 respectively to facilitate the manufacturing process of the joining member by stamping and pressing from a single sheet metal blank.

The side edge 12 of the base defines the inner periphery of the bridging member and is formed with an upstanding inverted U-section wall to provide, with the outer wall 15, 16, 17, a channel extending around the base to receive and contain a number of electrical cables extending from one cable tray run through the angle defined by the joining member to the next run. In the example illustrated the bridging member defines a right angle between the two cable tray runs connected by the bridging member.

To facilitate the connection the walls of the side 16 are formed with inner and outer integral extension members 19, 20. To allow the extensions to be inserted into the cable tray, the base portion of the double-walled form is cut away as indicated at 21. The extension portions 19, 20 have four spaced upstanding dimples 22 formed by upsetting the metal of the extension members to hold the members apart with a minimum separation between them. Elongate slots 23, 24 are formed in the extension members to receive spaced bolts for securing the extension members to the side walls of the cable trays to which the joining member is to be connected. The ends of the side wall 18 have similar extension members 25, 26 formed integrally with the walls of the side wall 18 and from which the base of the U is cut away as indicated at 27.The members 25, 26 are each formed with four upstanding dimples 28 and slots 29 as before. By cutting away the base of the U, the extension members 25, 26 can readily be bent as indicated at 30 adjacent the side wall 18 to lie parallel to the extension members 19 and 20 to receive and be secured to the side walls of an end cable tray in the run of cable trays as indicated above.

The edge 14 of the base of the joining member is formed with a down turned step 31 and an integral trapezoidal shaped flange 32 extends from the lower end of the step to engage under the base of the cable tray to be secured to the joining member to assist in supporting the cable tray. Slots 33 are provided in the flange for receiving fastenings for securing the joining member to the base of the cable tray. The free end of the outer side wall 17 and the other end of the side wall 18 are similarly formed for connection to the other cable tray runs.

The double form of extension walls for securing the side walls of the bridging member to the corresponding side walls of the cable trays provides a very strong joining connection with adjacent cable tray runs notwithstanding the reduction in material in the extensions caused by the elongate slots.

The tray described above is to create a right-angled corner between two elongate runs of cable trays. The same principles of construction can equally be applied to joining members providing other bend forms, intersections, cross overs, steps, reducers or risers between cable tray runs.

Reference is now made to Figures 4 and 5 of the drawings which illustrates a modified form of the sidewall extension members of a cable tray bridge for risers and small accessory components. In this case only the outer members 20, 26 of the side walls 16, 17 and 18 are extended and are folded back along their inner sides to create double-walled extensions as before. The side by side members of each extension are formed with raised spacer dimples and slots as previously described. The outer members of each extension may have six equi-spaced dimples and the inner members four. The arrangement is otherwise similar to that described above.

Claims

1. A cable tray bridging member to link in a run of cable trays comprising a one piece metal pressing providing a base and upstanding sides of double-walled form, the sides having double-walled extensions at each end to provide connection members for connecting the bridging member in a cable tray run.

2. A cable tray bridging member as claimed in Claim 1, wherein the double walls including the end extensions of each side of the bridging member are spaced apart and spacer elements are provided between the walls of the extensions to maintain the separation of the walls when clamped to the walls of the adjacent cable trays.

3. A cable tray bridging member as claimed in Claim 1 or Claim 2, wherein the double-walled sides of the bridging member are of inverted U-shaped cross section each having an outer wall extending upwardly from the base of the bridging member to the base of the U and an inner wall extending downwardly from the base of the U and stopping short of the base of the bridging member.

4. A cable tray bridging member as claimed in Claim 3, wherein the base of the U of each extension of the side is cut away to facilitate flexing of the extension to align with the sides of the cable tray to which the joining member is to be secured.

5. A cable tray joining member as claimed in any of the preceding claims wherein each side extension of the bridging member is formed with an elongate slot extending lengthwise of the extension to receive bolts for securing the extension to the side walls of an adjacent cable tray.

6. A cable tray bridging member substantially as described with reference to and as illustrated in Figures 1 to 3 or Figures 4 and 5 of the accompanying drawings.