GB2268838A - Cable tray connector - Google Patents

Abstract

A cable tray accessory, particularly for connecting cable trays (58, 60 fig 2) at an angle, is provided with fish plates (62, 64) and wherein at least one of the fish plates (62, 64) is attached to the remainder of the accessory which is a one-piece blank (10). In this way, the fish plates (62, 64) need not be laterally cropped in order to accommodate the coupling tongues (28-32) which are formed in the blank, but can have the full width of the cable tray (58, 60). The cable tray (58, 60) may be of either the single- or return-flange type and may be a reducer. <IMAGE>

Description

Improvements Relating to Cable Support Systems This invention relates to cable support systems, being systems comprising what are known as "cable trays" being elongated members of shallow U-section which serve to support electric cables, service pipes and the like.

These systems typically are installed in buildings and installations which utilise electric cable systems and where the cables have to be supported for example above ground level and which may require to travel between different levels in the building or structure.

In a complete installation of such a system, it is frequently required that cable tray lengths have to be connected end to end by means of accessories, and the present invention concerns such a component.

An accessory may be adapted to connect two or more than two cable tray ends and it may be in the nature of a T-junction for connecting three cable tray ends, a cross for connecting four cable tray ends or a reducer for connecting cable tray ends of different width.

A cable tray accessory to which the present invention relates comprises a base plate section and side wall sections, the base plate section and side wall sections serving to align with the base and side walls of the cable tray lengths to which the accessory is to be connected, and for the purposes of establishing the connection, the accessory to which the present invention relates is provided with extension tongues on the side wall sections for overlapping the side walls of the cable tray lengths, and a fish plate which is an extension of the base plate and underlies the adjacent cable tray end. The overlapping portions of the accessory and cable tray end are provided with apertures to enable the accessory and cable tray end to be coupled by suitable means such as bolts, springs or the like.

Recently, we have developed cable tray accessories in a novel manner providing that the accessory including the extension tongues and fish plates are formed in a one piece metal blank so that the blank is simply folded into erected condition after it is produced, in order to define the accessory, and such accessories are particularly successful.

However, in proceeding with this development, it has been discovered that a few shortcomings in the one piece accessories have been discovered and the present invention develops the technology further, and provides a modified form of accessory based upon the original work of producing one piece blanks erectable into accessories with side tongues and fish plates, and in accordance with the present invention, an accessory for connecting together cable tray ends comprises a sheet metal blank provided with the accessory base plate, the accessory side walls and integral tongues, but wherein the fish plates are formed separately, and are secured to the underside of the accessory base plate for example by spot welding.

Taking this measure enables the production of an accessory which has certain advantages over the one piece accessory described above and heretofore providing in itself a considerable step forward in the art.

In the one piece accessory, where the accessory is to connect cable tray lengths which lie at an angle to each other, and also in the case where the cable tray accessory connects aligned cable tray ends but where the cable trays are of different widths, the tongues or at least some of the tongues require to be angled relative to the direction in which the adjacent fish plate extends from the accesory base, resulting in fact in the fish plate having to be reduced or trimmed at the edges to accommodate the tongue, which means that the fish plate cannot be of full width over its entire length. In other words, the fish plate in being cropped takes up a trapezoidal form as opposed to the desired rectangular form and of the same width as the cable tray to which it is to be connected.

By providing that the fish plate is a separate item however, means that the fish plate can take any profile as desired and suitably it will be of the full width rectangular form providing maximum overlap surface with the cable tray end in order to enhance the strength of the coupling between the fish plate and the associated cable tray.

The problem associated with having to crop the fish plate when it is integral with the base plate of the accessory becomes more acute the narrower the fish plate because a relatively greater portion of the fish plate must be cropped to accommodate the tongues. This disadvantage does not apply in the case of an accessory according to the present invention. Also, the use of a spot welded fishplate also eliminates the need for joggling operations needed in one piece designs.

The present invention applies to cable tray accessories which are suitable for use with single flange cable tray or return flange cable tray. Single flange cable tray is cable tray wherein the side walls of the cable tray are simply turned upwardly relative to the base, and return flange cable tray is the type wherein the side walls are defined by side walls which have inwardly turned or double portions.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, wherein: - Fig. 1 is a blank of sheet metal for producing an accessory according to our original development work; Fig. 2 is a perspective view of the accessory formed by bending the blank of Fig. 1; Fig. 3 is a view similar to Fig. 1 but showing a blank for producing an accessory according to the embodiment of the invention; and Fig. 4 is a view corresponding to Fig. 2 but showing the accessory of Fig. 3 with its fish plates attached thereto.

Referring to the drawings, the blank 10 shown in Fig. 1 is of sheet metal, and is in accordance with our previously developed technology. The blank comprises a base 12 with outer side wall portions 14, 16 and an inner side wall portion 18. The side wall portions 14, 16 and 18 are provided with extensions 14A 16A and 18A which are adapted to be folded over about hinge lines 20, 22 and 24 in the erection of the blank.

Side wall portions 14 and 16 have extension tongues 26, 28 of the configuration shown, and inner side wall portion 18 has two of said extension tongues 30, 32.

Finally, the base 12 has integral fish plates 34 and 36 which have aperture patterns therein as indicated in Fig. 1.

In the formation of the blank, the fish plates 34 are joggled downwardly out of the plane of the base 12 at joggling line 38 and 40 so that the fish plates 34 and 36 can slide under the ends of cable tray lengths to be connected to the accessory which is constructed by erecting the blank of Fig.

1.

In Fig. 1, it will be seen that the fish plates 34 and 36 are in fact shaped along their lower edges in Fig. 1 (indicated by references 40 and 42) so as to provide clearance for the tongues 30 and 32. Thus, in fact the fish plates 34 and 36 cannot be made full size for fitting into the cable tray ends as will be explained in more detail in relation to Fig. 2.

The fish plates 34 and 36 are therefore "cropped" in order to achieve the blank layout of Fig. 1.

To erect the accessory of Fig. 1, it is simply a matter of folding up the side portions 14, 16 and 18 about fold lines 44, 48 and 50. The extensions 14A, 16A and 18A are folded inwardly, so that the configuration as shown in Fig. 2 is achieved. It is to be noted that in the illustration of Fig.

2, part of the inner side wall portion 18 is broken away to illustrate the fish plate 34 fully. The fish plate apertures are omitted in Fig. 2. The edges of outer side portions 14 and 16 which come together in the erection of the accessory are welded or otherwise joined along the line 52.

Fig. 2 illustrates the disadvantageous effect which results by forming the accessory in a single blank as shown in Fig.

1, with integral fish plates. Because of the cropping of the fish plates 34 and 36 along the edges 40 and 42, the fish plate 34 or 36 can only be made of the width 54 which is considerably narrower than the width 56 of the cable trays 58 and 60 which are to be coupled to the accessory via the fish plates 34 and the tongues 26 - 32. In coupling for example the cable tray end 60 to the accessory 10, the tongues 28 and 32 are inserted between the layers of the return flange walls of the cable tray 60, and the fish plate 36 slides to the underside of the base of the tray 60. The tray 60 has appropriate fixing apertures whereby the tray may be bolted to the fish plate and/or the tongues 28 and 32, but because of the narrow width 54 of the fish plate, securement is not as strong and positive as it might be were the fish plate 36 to be of the full width 56.

The present invention overcomes this difficulty and provides as shown in Fig. 3 that the accessory which would if formed completely of a single blank having integral fish plates would require the fish plates to be cropped, by providing that separate full width fish plates 62 and 64 are provided and are welded to the underside of the base 12 of the accessory. The base 12 is cut along lines 38 and 40 where the joggling is provided in the Fig. 1 arrangement.

In the blank projected illustration of Fig. 3, it can be seen that the tongues 30 and 32 overlap the fish plates 62 and 64, but in fact these fish plates preferably will be attached by the spot welding 66 after the blank 10 has been erected to the condition shown in Fig. 4, as the erected accessory can readily be held in a welding jig to enable the welding easily to be effected.

The accessory of Fig. 4 performs the same function as the accessory of Fig. 2 namely to connect lengths 58 and 60 of cable tray which lie at an angle relative to one another, but in the case of the arrangement of Fig. 4, the fish plates are of full width whereas in the arrangement of Fig. 2, the fish plates are cropped. The arrangement of Fig. 4 therefore provides a more positive and firmer connection between the accessory and the cable lengths.

The invention can be applied to accessories of different configuration including accessories which are T accessories for connecting three cable tray ends or cross accessories for connecting four cable tray ends. Again, when cable tray ends of different widths are to be connected by a reducer accessory, the invention can be applied. Indeed, the invention can be applied to any accessory wherein if the fish plate is formed integrally with the accessory blank and the projecting tongues cause the fish plate to be "cropped".

Claims (5)

1. A device for coupling together cable tray lengths (58,60), comprising a blank (10) of sheet material which is bendable to define a channel member having a base (12), side walls (14,16,18) and tongues (26-32) which extend from the ends of the side walls (14,16,18) at the ends of the channel member and are for overlapping the side walls of the cable tray lengths (38,60) so as to be couplable thereto, and wherein the channel side walls (14,16,18) converge towards at least one end of the channel member, characterised by a fish plate (62,64) which initially is a separate member but is attached to the base (12) of the channel member at said one end so as to overhang the base (12) of the channel member and provide a means of connecting the channel member to the adjacent cable tray length (58,60) and characterised in that the fish plate (62,64) extends across the channel member and for substantially the full spacing between the side walls (14,16,18) at said end.

2. A device according to claim 1, characterised in that the blank (10) is bendable to define a channel member comprising this section which angled one relative to another.

3. A device according to claim 2, characterised in that the channel member side walls (14,16,18) converge towards each end of the channel member, and each of said ends is provided with a said fish plate (62,64).

4. A device according to claim 1 characterised in that the blank is bendable into a channel member wherein the ends are aligned but one is wider than the other.

5. A cable tray accessory formed by bending a blank according to any preceding claim.