IE20100795A1

IE20100795A1 - Cable tray system and a connecting device therefor

Info

Publication number: IE20100795A1
Application number: IE20100795A
Authority: IE
Inventors: Ivan Major; Kyle Adair
Original assignee: Unitrunk Ltd
Priority date: 2009-12-22
Filing date: 2010-12-21
Publication date: 2011-06-22
Also published as: GB2476569A; GB2476569B; IE86566B1; GB0922334D0; GB201021560D0

Abstract

a cable tray system comprising a plurality of cable tray sections longitudinally joined together to define one or more elongate tracks for guiding, supportinig and mounting a plurality of electrical cables, wherein adjacent cable tray sections are connected together by means of a plurality of connecting devices, each connecting device passing through aligned pairs of apertures in overlapping portions of adjacent tray sections and/or in a respective tray section and an intermediate coupling element, whereby said cable tray sections can be securely joined together without the use of tools.

Description

A cable tray system comprises an assembly of channel shaped tray sections and associated fittings forming a rigid structural system used to securely fasten, guide and support electrical cables. Cable tray systems are used within the construction industry to house electrical cabling in mainly commercial or industrial buildings. Such cable tray systems typically comprise a plurality of interconnected tray sections, each formed from a strip of material which has its side edges bent 10 upwardly to define a shallow U-shaped channel, Apertures are formed in each cable tray section at regular intervals for ventilation and for cable fixing and to allow the cable tray sections to be joined together and attached to mounting structures. Standard elongate channel shaped cable tray sections and specially designed junction sections are adapted to be joined together such that the cable tray system can be assembled from a number of standard parts to provide the desired cable 15 routing for a particular application. This means that installation of a cable tray system involves the interconnection of a large number of separate cable tray sections and associated components.

Figure 1 illustrates a typical method of connecting adjacent cable tray sections. An end of a first tray section 1 is connected as a butt joint to an end of a second cable tray section 2. A separate external coupler 3 is placed around the outside of the joint between said cable tray ends, one for each side, These couplers 3 are pre-punched with holes corresponding to the pattern of holes provided in the cable tray sections 1,2. Nuts and bolts 4 are then fed through the aligned holes between the couplers and tray and tightened up using a screwdriver and spanner for security. Normally there would be eight nuts and eight bolts used per joint. A copper earth strap 5 is attached to the side of the cable tray using nuts and bolts for electrical continuity purposes.

Figure 2 illustrates a junction tray section 6 for providing a junction between three elongate cable tray sections 1. A coupler portion 7 is integrated into the design of the junction section 6 so that there is no need for separate external couplers. The fitting pattern is designed to overlap the holes in an adjacent tray section 1 tray so that four nuts and bolts 4 are required. Again, copper earth straps 5 are normally attached to the sides of the cable tray to ensure electrical continuity between the adjacent cable tray sections. Other types of specially shaped tray sections, such as bends and risers, may be connected together using the same method.

Such known cable tray systems require on the use of numerous nuts and bolts for assembly of the components of the system and are therefore time consuming to assemble.

According to a first aspect of the present invention there is provided a cable tray system comprising a plurality of cable tray sections longitudinally joined together to define one or more elongate tracks for guiding, supporting and mounting a plurality of electrical cables, wherein adjacent cable tray sections are connected together by means of a plurality of connecting devices, each connecting IE 1 Ο Ο 7 9 5 device passing through aligned pairs of apertures in overlapping portions of adjacent tray sections and/or in a respective tray section and an intermediate coupling element, whereby said cable tray sections can be securely joined together without the use of tools.

In one embodiment each connecting device comprises a strip of resilient material shaped to define an elongate pianar base section and a pair of depending arms extending from either end of said base section to extend through said pair of aligned apertures to join and secure together said adjacent tray sections and/or said respective tray section and said intermediate coupling element. Preferably the length of said base section is substantially equal to the spacing between said respective pair of apertures.

Preferably said arms are angled towards one another to retain said connecting device in place once the arms have been passed through said aligned apertures. The respective distal end of the arms may be bent outwardly to extend away from one another such that the spacing between said distal ends is substantially equal to or greater than the length of the base section to enable the connecting device to be pushed through said aligned apertures.

Preferably said aligned apertures formed in the tray sections and, where provided, in said intermediate coupling elements comprise elongate slots having a length substantially equal to the width of said base section of the connecting device.

Preferably each cable tray section comprises a strip of material which has its side edges bent upwardly to define a shallow U-shaped channel, at least a portion of the side edges of at least one of said cable tray sections being bent over to define an inverted V or U shaped lip at an upper end thereof, a side edge portion of an intermediate coupling element and/or a coupling portion of an adjacent cable tray section being adapted to be received within said lip to assist is connecting adjacent tray sections together. Preferably said portion of said side edges defining said lip is bent over towards an inside of the channel defined by the respective tray section such that said lip is formed on an inner side of said channel whereby said coupling element and/or said coupling portion of an adjacent cable tray section is received on an inside of said channel.

In one embodiment at least one coupling element is provided to extend between abutting ends of said adjacent cable tray sections. A single tray shaped coupling element may be provided to extend between adjacent cable tray sections to lie inside the elongate channel defined between said adjacent sections, upper ends of each side of the coupling element being received within respective lips of the sides of the adjacent cable tray sections. Alternatively a pair of coupling elements may be provided to iie between respective sides of the adjacent cable tray sections, each coupling element having a first section, adapted to lie against a side edge of each of the adjacent tray sections and to locate within said lip, and a second section, adapted to lie against a base portion of the cable tray sections, said first and second sections extending at right angles to one another.

JE 1 0 0 7 95 Said cable tray system may further comprise additional sections for joining three or more adjacent cable sections together to define a junction between said adjacent cable tray sections. Preferably said additional sections include integrally formed coupling portions adapted to overlap with an end of an adjacent cable tray section. Preferably said coupling portions include side edges adapted to be received within said inverted V or U shaped lips of an adjacent cable tray section, at least one of said connecting devices passing though aligned pairs of apertures in overlapping portions of said coupling portion of said additional section and said adjacent cable tray section.

The cable tray system may further comprise at lest one cover section for covering at least a portion of at least one of said plurality of cable tray sections. Preferably said at least one cover section is attachable to said at least one cable tray section by means of releasable fastenings. Preferably said releasable fastening enable the cover section to be fitted without requiring the use of tools. In one embodiment said releasable fastenings comprise resilient clips shaped to engage the sides of the cable tray section and cover section to extend between the cable tray section and cover section.

According to a further aspect of the present invention there is provided a connecting device for joining together sections of a cable tray system, said connecting device comprising a strip of resilient material shaped to define an elongate planar base section and a pair of depending arms extending from either end of said base section to extend through a pair of aligned apertures formed in said cable tray sections and/or in respective cable tray sections and in an intermediate coupling element, whereby said cable tray sections can be securely joined together without the use of tools.

According to a further aspect of the present invention there is provided a fastening device for mounting on a threaded rod, said fastening device comprising a coiled spring dimensioned to engage and grip said threaded rod to retain the fastening device thereon. Preferably end regions of the coiled spring define elongate legs extending in spaced apart relationship along the length of the spring such that the end regions can be squeezed together to open up the coils of the spring to enable the fastening device to be slid along the threaded rod, the coils closing upon release of said end regions to grip the threaded rod. Preferably said legs are arranged parallel to one another and parallel to the longitudinal axis of the spring. Preferably the pitch of the coils of the spring is substantially equal to the thread pitch of the threaded rod upon which the fastening device it to be mounted.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:IE 1 0 0 7 95 Figure 3 is a perspective view of a join between two sections of a cable tray system according io a first embodiment of the present invention; Figure 4 is a perspective view of a join between two sections of a cable tray system according to a modified or alternative embodiment of the present invention; Figure 5 is a perspective view of a spring clip according to an embodiment of the present invention; Figure 6 is a perspective view of a cable tray section; Figure 7 is a perspective view of a coupling element of the cable tray system of Figure 3; Figure 8 is a perspective view of a coupling element of the cable tray system of Figure 4; Figure 9 is a perspective view of an extension section of the cable tray system; Figure 10 is a perspective view of a further section of the cable tray system providing a junction between three adjacent cable tray sections; Figure 11 is a perspective view of a known cable tray system showing the attachment of a cover section; Figure 12 is a perspective view of an attachment clip for a cable tray system in accordance with an 25 embodiment of the present invention for attaching a cover section; Figure 13 illustrates the attachment clip of Figure 12 in use; Figure 14 is a perspective view of a known system currently used in order to fix cable tray onto 30 channel or cantilever arms; Figure 15 illustrates a coupling clip for connecting a cable tray section to a support channel for supporting the cable tray section; Figure 16 illustrates the coupling clip of Figure 15 in use to connect a cable tray section to a support channel; Figure 17 is a perspective view of a known arrangement for suspending a support channel from a support using threaded bolts and nuts; IE 1 0 07 95 Figure 18 is a perspective view of an arrangement for suspending a support channel of a cable tray system in accordance with an embodiment of the present invention; and Figure 19 is a perspective view of a retaining member of the suspension arrangement of Figure 18.

As discussed above, prior art cable tray systems uses nuts and bolts to join together sections of the cable tray system and are thus time consuming to assemble. In a cable tray system in accordance with an embodiment of the present invention, as illustrated in Figures 3 to 10, specially designed spring clips 10 replace these nuts and bolts. These spring clips 10 can be rapidly inserted, without the use of tools, to quickly interconnect adjacent cable tray sections, making the cable tray system considerably faster to assemble. This ultimately saves time for the installer and as a result makes the system more appealing.

Figure 3 shows the connection between two elongate cable tray sections 11,12 according to a first embodiment of the present invention. First and second tray sections 11,12 are placed in abutting contact with a tray shaped coupling element 13 (see Figure 7) located therebetween, the sides ofthe coupling element 13 being located within inverted V shaped lips 14,15 defined by the bent over sides of the tray section 11,12 such that vertical bending loads are transferred across the join between the tray section 11,12 by the coupling element 13 by virtue of its engagement within the lips 14,15 of the tray sections 11,12. Elongated slot iike holes 16 are provided in the base ofthe coupling element 13 to be aligned with corresponding holes 17 formed in the first and second tray sections 11,12, such that spring clips 10 can be inserted through respective pairs of aligned holes 16,17 in overlapping portions of the tray sections 11,12 and the coupling element 13 to secure the tray sections 11,12 together.

As shown in Figure 5, each spring clip 10 comprises a strip of resilient material, such as spring steel, shaped to define an elongate planar base section 20 and a pair of depending arms 21,22 extending from either end of said base section 20 to extend through a pair of aligned holes 16,17 in the respective tray sections 11,12 and coupling element 13 to join and secure together said adjacent tray sections 11,12 and/or said respective tray section 11,12 and said intermediate coupling element 13. The length of said base section 20 of each clip 10 is substantially equal to the spacing between each pair of holes 16,17 through which the clip 10 is to be inserted.

The arms 21,22 of each clip 10 are angled towards one another to retain the clip 10 in place once the arms 21,22 have been passed through an aligned pair of holes 16,17. The respective distal end 23,24 of the arms are bent outwardly to extend away from one another such that the spacing between said distal ends 23,24 is substantially equal to or greater than the length of the base section 20 to enable the clip 10 to be pushed through a pair of aligned holes 16,17 by hand without the use of any tools. Typically four clips 10 may be used for each joint, a pair of clips 10 being provided for coupling each tray section 11,12 to the intermediate coupling element 13.

IE 1 007 95 The aligned holes 16,17 formed in the tray sections 11,12 and in the intermediate coupling element 13 comprise elongate slots having a length slightly greater than the width of said base section 20 of the clip 10 to allow the arms 21,22 to pass therethrough.

When joining abutting ends of standard elongate cable tray sections 11,12, an internal coupler is used as opposed to the prior art external couplers shown in Figure 1. The internal coupler may consist of a one-piece coupling element 13 (as shown in Figures 3 and 7) or, in an alternative embodiment shown in Figures 4 and 8, two separate internal coupling elements 18,19 may be used, depending on the application. The coupling element 13 or elements 18,19 is provided with pre10 punched holes 16 located to be brought into alignment with corresponding hole 17 in the cable tray sections 11,12 to allow the insertion ofthe spring clips 15 therethrough when the coupling elements 18,19 are located within adjacent ends of abutting tray sections 11,12.

The electrical continuity ofthe cable tray system has been tested (both single piece coupling element 13 and two-piece 18,19) and demonstrates that the requirement for a copper earth strap is eliminated. The fact that the need for copper earth straps has been removed is appealing to the customer because from saving on both the cost of earth straps and the time necessary to install them.

Where it is desired to provide a variable length section of the cable tray system an expansion tray section 30 may be provided, as shown in Figure 9, the expansion tray section 30 being dimensioned such that an end of a standard tray section 11/12, as shown in Figure 6 may be inserted into an end of the expansion tray section 30 in overlapping fashion, the two sections 11/12, 30 being secured together by the insertion of spring ciips 15 through aligned pairs of holes 32 in the overlapping portions of the two sections 11/12,30. The expansion tray section 30 eliminates the need for couplers to expand a length of cable tray system and saves time by doing away with the need to cut a piece of cable tray in order to lengthen the cabie tray As shown in Figure 10, further tray sections 40 may be provided for forming junctions between three or more sections of a cable tray system. Again, as with the other sections, spring clip 15 are inserted through aligned pairs of holes 42 in overlapping portions of adjacent tray sections to secure the tray sections together. Side portions 44,45 of the further tray section 40 are adapted to be received within the lips 14,15 on the sides of the adjacent tray sections 11/12 to transfer vertical loading between the adjacent sections.

Figure 11 shows a fully assembled section of known cable tray using a ventilated cover 50. The cover 50 is typically attached to the tray section 11 using angled brackets 52 and nuts and bolts 54,55 and spring washers. Such arrangement is exceedingly tricky to assemble the system because of the number of spring clips, nuts, bolts and brackets used. Because of the number of components and their inherent trickiness to assemble it means that is takes a long time to assemble this part of the cable tray system. Also, because of the small size of some of the components many are IE 1 007 95 dropped/lost whilst being installed and sometimes this can lead to a shortage of parts, which in turn causes frustration for the installer.

Figure 12 shows an attachment clip 100 for connecting a ventilated cover 50 to a cable tray 11 which 5 overcomes these problems. The attachment clip 100 is formed from a resilient material, such as spring steel or a resilient plastic, and has a lower part 102 shaped to engage and grip the side of a cable tray section 11 and an upper part 104 shaped to engage the side of a cover 50. As can be seen from Figure 12, the tower part 102 of the clip 100 has a downwardly and outwardly depending inner part 106 to engage the lip 14,15 of the cable tray 11 section to retain the clip 100 thereon.

As can be seen from Figure 13, at least one clip 100 is mounted on each side of the cable tray section 11 and a ventilated cover 50 can be mounted in the upper parts 104 of the clips 100 to be located therebetween to attach the cover 50 to the cable tray section 11. Thus the clips 100 can be used to easily attach a cover section 50 to one or more of the cable tray sections 11,12 without requiring the use of tools or other fastening devices. The clips 100 therefore provide a “snap-fit'' functionality whereby the clips 10 utilise the cable tray profile in order to fix the cover 50 onto the cable tray section 11. The cover 50 snaps in very easily using the “U-shape” profile of the upper part 104 or the attachment clips 100. This entire assembly process is carried out easily by hand i.e. no toois required. The attachment clips 100 eliminate the need for hoies in the cable tray covers 50.

The attachment clips 100 do not rely on holes in the cable tray section 11, therefore can be placed anywhere along the cable tray length without any forward planning. There are only three main components in the new system, thereby reducing the chances of losing many small components like in the prior art system.

Figure 14 shows the system currently used in order to fix cable tray 11 onto a support channel 110. The problems with this system are as follows: • The threaded hole spring channel nut 112 must line up with a corresponding hole in the cable tray 11 so that a bolt 114 can be passed through in order to provide fixation. This can be extremely difficult depending on the weight of the cable tray 11 and the dimensions they are working within, and is frustrating in any instance.

• The spring channel nut 112 is very fiddly to install into the channel, and often falls within the channel. Again, this is time consuming and frustrating for the installer.

Figure 16 shows an improved system in accordance with an embodiment of the present invention. 35 The cable tray section 11 is connected to the support channel 110 by the use of specially shaped spring clips 120, as shown in more detail in Figure 15. Each clip 120 comprises a base portion 122 adapted to sit in the bottom of the channel 110 and a pair of curved resilient projections 124,126 extending from either side of a central portion of the clip to engage under respective side lips 116 of the channel 110 to retain the clip 120 within the channel 110. An upper end of the clip is curved to define a hook portion 128 adapted to engage over the upper edge of the side lips 14,15 of the cable tray section 11.

IE 1 007 95 In use, the clip 120 can be easily installed into the channel 110 by placing the clip into the channe! so that the base portion abuts the bottom of the channel 110 and rotating the clip to extend transverse to the channel so that the projections 124,126 engage the side lips 116 of the channel 110. The cable tray section 11 can then be snapped into place under the hook portions 128 of opposing pairs of clips 120.

. The advantages of this system as opposed to the current system are as follows: • The installation time will be reduced due to the “snap-fit” operation.

· The clips 120 are much less prone to falling into the channel, thereby greatly reducing frustration for installers.

• The fixation of each clip 120 does not rely on any holes in the cable tray, therefore the need to have holes lined up is eliminated. This is probably the single greatest advantage of the new system.

· The system can be assembled and disassembled by hand, eliminating the need for tools.

Figure 17 illustrated how a cable tray section 11 is currently hung from a support using threaded bars 130, each fitted with a nut 132 and a washer screwed onto the underside through a support channel 110. There are a number of problems with using a nut and washer to hang a tray section 11 from a support using threaded bars 130. These are as follows: • The nut and washer can take considerable time to screw up the length of the threaded bar 130 depending on how long it has to travel.

• The threads on the end of the threaded bar 130 must be “clean” (i.e. properly cut) so that the nut 132 can catch onto the bar 130. This has to be dealt with for every piece of threaded bar 130 that is cut, and is again time consuming.

• Nuts 132 and washers are easy to drop and many will be lost on a job, adding to costs and causing potential shortage problems .

Figure 18 shows a cable tray assembly according to an embodiment of the present invention wherein 30 improved retaining devices 140 are used to hang the cable tray section 11 from a support using threaded bars 130 extending through holes in the tray section 11 and a support channel 110. These retaining devices 140 directiy replace the nut and washer, and have a number of distinct advantages.

Figure 19 shows how the retaining device 140 in more detail. Each retaining device 140 comprises a 35 coiled spring having a coiled section 142 having a pitch substantially equal to the pitch of the threads of the threaded bar 130, wherein the ends of the coiled section 142 extend outwardly from the coiled section 142 and terminate in parallel spaced apart legs 144,145 extending in parallel side by side relationship substantially parallel to the axis of the coiled section 142, whereby the legs 144,145 can be squeezed together to open up the coils of the coiled section 142 of the retaining device 140 to enable the device 140 to be slid up a threaded bar 130. Once the squeezing force applied to the IE 1 007 95 g legs 144,145 is relaxed, the coils of the coiled section 142 close up such that the device 140 grips onto the threaded bar 130 at a desired position to support the cable tray section 11 therefrom.

The retaining devices 140 are much faster to install than a traditional nut and washer because they 5 are can slide up the threaded bar 130 and there is not the requirement to laboriously screw the springs up the bar to get them into position. The retaining devices 140 can be installed by hand, by squeezing the legs 144,145 between finger and thumb, and therefore no tools are required, unlike the nut and washer where a spanner is needed. Furthermore, the threads on the end of the threaded bar 130 do not have to be “clean” for a retaining device 140 to be installed, therefore eliminating one part of the installation process.

The principle of operation of the retaining devices 140 can be broken down asfollows:• The two legs 144,145 which protrude from the helical coiled section 142 are squeezed together using a person’s thumb and forefinger, This opens up the helical coils sufficiently to allow the spring pass over the threads of the threaded bar 130, thus enabling the device 140 to be slid up and down the bar 130.

• Once the legs 144,145 are released by letting go with thumb and forefinger, the helical coiled section 142 close in and wrap around the threaded bar 130, whereby the retaining device 140 is fixed onto the threaded bar 130 to support the channel 110 and cable tray section 11 therefrom.

The strength under load of the retaining device 140 is extremely high because the pitch of the helical 25 coils of the coiled section 142 of the device 140 are dimensioned to precisely match the pitch of the threads on the threaded bar 130. This means that the coils of the device 140 fully wrap around the threaded bar 130 and create an incredibly strong fixing under load.

The invention is not limited to the embodiment(s) described herein but can be amended or modified 30 without departing from the scope of the present invention.

Claims

1. A cable tray system comprising a plurality of cabie tray sections longitudinally joined together to define one or more elongate tracks for guiding, supporting and mounting a plurality of electrical cables, wherein adjacent cable tray sections are connected together by means of a plurality of connecting devices, each connecting device passing through aligned pairs of apertures in overlapping portions of adjacent tray sections and/or in a respective tray section and an intermediate coupling element, whereby said cable tray sections can be securely joined together without the use of tools.

2. A system as claimed in claim 1, wherein each connecting device comprises a strip of resilient material shaped to define an elongate planar base section and a pair of depending arms extending from either end of said base section to extend through said pair of aligned apertures to join and secure together said adjacent tray sections and/or said respective tray section and said intermediate coupling element

3. A system as claimed in claim 2, wherein the length of said base section is substantially equal to the spacing between said respective pair of apertures.

4. A system as claimed in claim 2 or claim 3, wherein said arms are angled towards one another to retain said connecting device in place once the arms have been passed through said aligned apertures.

5. A system as claimed in claim 4, wherein the respective distal end of the arms are bent outwardly to extend away from one another such that the spacing between said distal ends is substantially equal to or greater than the length ofthe base section to enable the connecting device to be pushed through said aligned apertures.

6. A system as claimed in any preceding claim, wherein said aligned apertures formed in the tray sections and, where provided, in said intermediate coupling elements comprise elongate slots having a length substantially equal to the width of said base section ofthe connecting device.

7. A system as claimed in any preceding ciaim, wherein each cable tray section comprises a strip of materiai which has its side edges bent upwardly to define a shallow U-shaped channel, at least a portion of the side edges of at least one of said cabie tray sections being bent over to define an inverted V or U shaped lip at an upper end thereof, a side edge portion of an intermediate coupling element and/or a coupling portion of an adjacent cabie tray section being adapted to be received within said lip to assist is connecting adjacent tray sections together.

8. A system as claimed in claim 7, wherein said portion of said side edges defining said lip is bent over towards an inside of the channel defined by the respective tray section such that said fip is IE 1 007 95 formed on an inner side of said channel whereby said coupling element and/or said coupling portion of an adjacent cable tray section is received on an inside of said channel.

9. A system as claimed in any preceding claim, wherein at least one coupling element is 5 provided to extend between abutting ends of said adjacent cable tray sections.

10. A system as claimed in claim 9, wherein a single fray shaped coupling element is provided to extend between adjacent cable tray sections to lie inside the elongate channel defined between said adjacent sections, upper ends of each side of the coupling element being received within respective 10 lips of the sides of the adjacent cable tray sections.

11. A system as claimed in claim 9, wherein a pair of coupling elements are provided to lie between respective sides of the adjacent cable tray sections, each coupling element having a first section, adapted to lie against a side edge of each of the adjacent tray sections and to locate within 15 said lip, and a second section, adapted to lie against a base portion of the cable tray sections, said first and second sections extending at right angles to one another.

12. A system as ciaimed in any preceding claim, further comprising additional sections for joining three or more adjacent cable sections together to define a junction between said adjacent 20 cable tray sections.

13. A system as claimed in claim 12, wherein said additional sections include integrally formed coupling portions adapted to overlap with an end of an adjacent cable tray section. 25

14. A system as claim 13, wherein said coupling portions include side edges adapted to be received within said inverted V or U shaped lips of an adjacent cable tray section, at least one of said connecting devices passing though aligned parrs of apertures in overlapping portions of said coupling portion of said additional section and said adjacent cable tray section. 30

15. A system as claimed in any preceding claim, further comprising at lest one cover section for covering at least a portion of at least one of said plurality of cable tray sections.

16. A system as claimed in claim 15, wherein said at least one cover section is attachable to said at least one cable tray section by means of releasable fastenings.

17. A system as claimed in claim 16, wherein said releasable fastening enable the cover section to be fitted without requiring the use of tools.

18. A system as claimed in claim 17, wherein said releasable fastenings comprise resilient clips 40 shaped to engage the sides of the cable tray section and cover section to extend between the cable tray section and cover section. IE 1 007 95

19. A connecting device for joining together sections of a cable tray system, said connecting device comprising a strip of resilient material shaped to define an elongate planar base section and a pair of depending arms extending from either end of said base section to extend through a pair of 5 aligned apertures formed in said cable tray sections and/or in respective cable tray sections and in an intermediate coupling element, whereby said cable tray sections can be securely joined together without the use of tools.

20. A connecting device as claimed in claim 19, wherein said arms are angled towards one 10 another to retain said connecting device in place once the arms have been passed through said aligned apertures.

21. A connecting device as claimed in claim 20, wherein the respective distal end of the arms are bent outwardly to extend away from one another such that the spacing between said distal ends 15. Is substantially equal to or greater than the length of the base section to enable the connecting device to be pushed through said aligned apertures.

22. A fastening device for mounting on a threaded rod, said fastening device comprising a coiled spring dimensioned to engage and grip said threaded rod to retain the fastening device thereon.

23. A fastening device as claimed in ciaim 22, wherein end regions of the coiled spring define elongate legs extending in spaced apart relationship along the length of the spring such that the end regions can be squeezed together to open up the coils of the spring to enable the fastening device to be slid along the threaded rod, the coils closing upon release of said end regions to grip the threaded 25 rod.

24. A fastening device as claimed in claim 23, wherein said iegs are arranged parallel to one another and parallel to the longitudinal axis of the spring. 30

25. A fastening device as claimed in any of claims 22 to 24, wherein the pitch of the coils of the spring is substantially equal to the thread pitch of the threaded rod upon which the fastening device it to be mounted.

26. A cable tray system substantially as herein described with reference to the accompanying 35 drawings.