GB2205200A

GB2205200A - Improvements relating to manufacture of elbows for cable trunking

Info

Publication number: GB2205200A
Application number: GB08712133A
Authority: GB
Inventors: Ian Frank Took
Original assignee: MITA Ltd
Current assignee: MITA Ltd
Priority date: 1987-05-22
Filing date: 1987-05-22
Publication date: 1988-11-30
Anticipated expiration: 2007-05-22
Also published as: GB2205200B; GB8712133D0

Abstract

An elbow 5 comprises 3, 1, two sections, each section consisting of a pair of identical parts (1, 3) arranged to interengage, one section pair (1) being welded or otherwise bonded together, the other section pair (3) being attached to said one section pair by screws (35) or spring clips (59). In use trunking extends into the elbow ends up to stops formed in part (1). As shown in (Figs 5-8) the welded parts may alternatively comprise the inside radius of the elbow. <IMAGE>

Description

DESCRIPTION IMPROVEMENTS RELATING TO ELBOWS FOR CABLE Bx ING-. IMPROVEMENTS RELATIG TO ELBOWS FOR CABLE T"nlrKING-.

The present invention relates to an elbow for cable trunking and a method of manufacturing said elbow.

Cable trunking is designed in elongate sections of generally rectangular or square transverse cross-section, and whilst said sections are required to be coaxially inter-connected to form a longer length of trunking, it is also necessary to interconnect sections of trunking arranged at right angles to each other and this is where an elbow is used. The trunking and elbows are preferably made from a suitable plastics material. However, whilst the tunking can be relatively cheaply extruded, the elbows have to be injection moulded, and due to their size and configuration, this is a capitally intensive exercise when first tooling up.

Alternatively, the elbows can be fabricated. out of a number of different pieces. However, this is expensive due to the large number of different pieces required and the lengthy manual operation of assembly.

The aim of the present invention is to provide an elbow which is relatively cheap and simple to manufacture.

According to the present invention there is provided an elbow comprising two pairs of like component parts which are adapted to interengage and be secured together to form the elbow.

By utilising two pairs of like components, only two different component parts are used for constructing the elbow, and thus the tooling costs for manufacturing the parts by injection moulding a suitable plastics material are minimised - only two uncomplex and/or low cost moulds being necessary.

In one embodiment of the present invention one component part is in the form of an elongate member with a generally U-shaped transverse cross-section, one axial end region being designed to partially overlap with and mate with an end region of a like component part to form the outer region of the elbow.

The overlapping regions are preferably bonded or welded, e.g. spot welded, together. The other component part is in the form of an elongate tray-like member with upstanding side edges which can mate with said one component part to close the U-shaped transverse cross-section and form the inside part of the elbow. One axial end edge of said other component part is designed to interengage with a like component part so as to prevent relative lateral movement therebetween, and to secure said tray-like other component parts to said one component parts, the members are screwed together.

In a modified form of said one embodiment, apertures or recesses are provided in the upstanding side edges of each elongate tray-like member and resilient tongue-like projections with lateral end flanges, project above the sides of the U-shaped transverse cross-section so that with the different component parts mated together the lateral end flanges each engage in an aperture or recess to thus secure the parts together. The need for screws is thus obviated, so that small dimension elbows can be constructed without such screws impairing the available usable cross-section within the elbow.

In another embodiment of the present invention tray-like component parts form the outer part of the elbow and generally U-shaped transverse cross-section parts define the inner part of the elbow. Again, screws or resilient projections can be used to secure the different component parts together, whilst overlapping regions of said generally U-shaped transverse cross-section parts are preferably bonded or welded, to thus maintain the elbow securely as an integral unit.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figs.l, la and lb are perspective views of a first embodiment of the present invention; Fig.2 is an exploded view of the embodiment of Figs.l, la and lb: Fig.2a is a perspective view of a first component part of the embodiment of Figs. 1 and 2; Fig.2b is an enlarged detail of an edge region of the component part of Fig.2a; Fig.2c is a perspective view of the second component part of the embodiment of Figs. 1 and 2; Figs.3, 3a and 3b are perspective views of a second embodiment of the present invention; Fig. 4 is an exploded view of the embodiment of Figs.3, 3a and 3b; Figs.5, 5a and 5b are perspective views of a third embodiment of the present invention;; Fig.6 is an exploded view of the embodiment of Figs.S, 5a and Sb; Figs.7, 7a and 7b are perspective views of a fourth embodiment of the present invention; and Fig.8 is an exploded view of the embodiment of Figs.7, 7a and 7b.

The first embodiment of the present invention illustrated in Figs. 1 and 2 of the accompanying drawings comprises a first component part generally designated 1, and a second component part 3, two pairs of said component parts 1,3 being mated and secured together to form an elbow 5.

Each of said first component parts 1, being elongate and having a generally U-shaped transverse cross-section with one end edge 7 being squared, whilst the other end edge 9 is shaped to interengage, partially overlap and mate with the corresponding end edge 9 of the other of said identical first component parts 1. Said other end edge 9 of each of said first component parts 1 is cutaway as at 11 on one of the sides of the U-shaped cross-section and has a triangular reduced thickness region 13 adjacent thereto. The other side of the U-shaped cross-section has a triangular reduced thickness region 15 which in the assembled state engages flush against the inside surface of said triangular reduced thickness region 13 on the other of said identical first component parts 1.By virtue of this triangular configuration said first component parts 1 are held at right angles to each other in the assembled state. The base of the end edge 9 is on one half 17 squared off, whilst the other half has an axially projecting lip 19 with a further lip 21 projecting normally thereto. In the assembled state the squared half 17 of the end edge 9 of one of said first component parts 1 engages between said lips 19,21 of the other of said first component parts 1.

When assembled together the identical first component parts 1 form the outer part of the elbow 5, and to secure the parts 1 together the overlapping interengaged triangular regions 13,15 are bonded or welded together. Projecting normally from the base of each said first component part 1, adjacent to the sides of the U-shaped cross-section, are two screw columns 23. Each screw column 23 has a recess 25 in its upper end with part 27 of the wall cutaway facing said one end edge 7. A blind bore with a threaded insert 29 is provided in the recess 25, the insert 29 being coaxial with the column 23. Also provided in the base of each first component part 1 are two stops 31 which, in the completed elbow, limit the insertion of cable trunking. Further, to secure the cable trunking in the elbow 5 an adhesive pad 33 is provided on said base between the stops 31 and said one end edge 7.

To complete the elbow 5 a pair of second component parts 3 are mated with said assembled first component parts 1 and each other, and screwy to the first component parts 1 by means of screws 35 which engage with said threaded inserts 29. Each of said second component parts 3 is an elongate tray-like member with upstanding side edges 37. Each of said side edges 37 has a recessed lip 39 on the outside of said side edges 37, which can engage with a recessed lip 41 on the inside of the upper edge of each of the sides of the U-shaped cross-section of said first component parts 1.One axial end 43 of each said second component part is squared whilst the other end 45 is shaped with the base of the tray-like member being curved as at 47 and the sides cutaway as at 49 and provided with opposed recessed lips 51,53, i.e. lip 51 is on the inside of one side edge and lip 53 is on the outside of the other side edge. The end edge 53 of the curved base 47 is divided into two halves, one half having a recess 55 and the other half being provided with a triangular lip 57. When said second component parts 3 are interengaged said lip 57 on one of said second component parts 3 engages with the recess 55 on the other of said second component parts and said lips 51,53 interengage so that said second component parts 3 are at right angles to each other.

The second component parts 3 are then mated with the assembled first component parts 1 so that said lips 39,41 interengage, and screws 35 are passed through bores 57 in each of said second component parts 3 and engaged with said threaded inserts 29 to form the elbow 5 as an integral unit. Said second component parts 3 thus form the inside part of the elbow 5.

A modified version of the embodiment of Figs. 1 and 2 is shown in Figs. 3 and 4, like reference numerals being used for equivalent features, the sole difference lying in the means of securing said second component parts 3 to said first component parts 1.

Instead of screws 35, resilient elongate tongues 59 project from the sides of the U-shaped cross-section first component parts 1, above the upper edge of said sides, said tongues having a lateral flange 61 which in use engages in an aperture 63 in the side edges 37 to thus secure said parts 1,3 together. By flexing these tongues 59 the flanges 61 can be moved out of apertures 62 allowing parts 1,3 to be separated. This construction optimises the useful cross-section available within the elbow 5 allowing a smaller elbow to be constructed without the screw columns blocking a major part of the elbow cross-section.

In another embodiment of the present invention illustrated in Figs. 5 and 6 of the accompanying drawings, identical first component parts 65 mate together to form the outer part of the elbow 67 and identical second component parts 69 mate, partially overlap and are secured together to form the inner part of the elbow 67.

Said first component parts 65 are each elongate tray-like members with upstanding side edges 71. One end 73 is square and the other end 75 is shaped to engage and mate with said other end 75 of said other first component part 65. Said other end 75 of each first component part 65 has one half 77 which is squared and another half which has an axially extending lip and recess 79. The ends of the side edges at said other end 75 are angled and provided with opposed recesses i.e. one recess is on the outside of a side edge and the other recess is on the inside of the other side edge.

Said second component parts 69 are elongate with a U-shaped transverse cross-section. Each second component part 69 has a base 85 which extends for part of the axial extent of said second component part 69, one end 87 of the base 85 being squared whilst the other end region 89 is curved and divided into a recessed half 91 and a further half 93 having a triangular lip which mates with the recessed half 91 on the other identical second component part 69, in the assembled condition. The sides of the U-shaped cross-section adjacent to said other end region 89 are also shaped, one side being formed as a triangular reduced thickness region 95 and the other side being rectangular and formed with a triangular reduced thickness region 97.When two identical second component parts 69 are mated said triangular reduced thickness regions 95,97 overlap each other and are welded together to hold said second component parts 69 at right angles to each other. Projecting normally from the base 85 are a pair of screw columns 99 and a pair of stops- 101; an adhesive pad 102 being provided between said stops 101 and said one end 73 of said second component part.Each screw column 99 has an axial bore with a threaded insert and said first component parts 65 can be secured to said second component parts 69 by screws 103 passing through bores on said first component parts 65 and engaging with said threaded inserts; the mating edges of said first and second component parts 65,69 having opposed lips, i.e. one part has a lip on the outside of the edge and the other part has a lip on the inside of the edge, to thus provide for positive interengagement and a smooth outer and inner surface. In the completed elbow 67 the stops 101 and friction pad 102 serve to locate and secure the end region of a section of cable trunking in the elbow 67.

A modified version of the embodiment of Figs. 5 and 6 is shown in Figs. 7 and 8, like reference numerals being used for equivalent features, the sole difference lying in the means of securing said first and second component parts 65, 69 together. Instead of screws 103, resilient elongate tongues 105 project from the sides of the U-shaped cross-section, second component parts 69, abdve the edges of said sides, said tongues 105 having a lateral flange 107 which, in use, engages in an aperture 109 in the side edges of the first component parts 65 to thus secure said parts 65,69 together. By flexing the tongues 105, the flanges 107 can be moved out of the apertures 109 allowing the parts 65,59 to be separated. This construction optimises the useful cross-section available in the elbow 67 allowing s smaller elbow to be constructed without screw columns impairing the through elbow cros-rction.

The present invention thus provides an elbow constructed from at least one pair of identical component parts, whereby, if especially injection moulded from a suitable plastics material,tooling and manufacturing costs are minimised.

Claims

1. An elbow comprising two pairs of like component parts which are adapted to interengage and be secured together to form the elbow.

2. An elbow as claimed in claim 1, in which each component part of one pair of component parts is in the form of an elongate member with a generally U-shaped transverse cross-section, one axial end region being designed to partially overlap and mate with an end region of a like component part to form a region of the elbow, each component part of the other pair of component parts being in the form of an elongate tray-like member with upstanding side edges which can mate with a component part of said one pair to close the U-shaped transverse crosssection, said other pair of component parts interengaging with each other to form the remainder of the elbow.

3. An elbow as claimed in claim 2, in which said one pair of component parts form the outer region of the elbow and said other pair of component parts forms the inside region of the elbow.

4. An elbow as claimed in claim 2, in which said one pair of component parts forms the inside region of the elbow and said other pair of component parts form the outer region.

5. An elbow as claimed in any of claims 2,3 or 4, in which the component parts of said one pair of component parts, are welded or bonded to each other.

6. An elbow as claimed in any one of claims 2 to 5, in which the component parts of said other pair of component parts, are bolted to the component parts of said one pair of component parts.

7. An elbow as claimed in claim 6, in which the bolts pass through apertures in one component part and are secured into threaded inserts located in elongate columns which project from another component part.

8. An elbow as claimed in any one of claims 2 to 5, in which the component parts of said one pair of component parts are secured to the component parts of said other pairs of component parts by resilient tonguelike projections with lateral end flanges, which project from within one component part and the side edges of said one component part, said flanges engaging in apertures or recesses in another component part with which said one component part is mated.

9. An elbow as claimed in any one of the preceding claims, in which stops are provided in at least one of the component parts forming each end region of the elbow, on an inside wall, said stops serving to limit the insertion of trunking sections into the elbow.

10. An elbow as claimed in any one of the preceding claims, in which an adhesive pad is provided in an inside wall of a component part at each end region of the elbow, said adhesive pads serving to at least assist in securing the elbow to a trunking section inserted into the elbow.

11. An elbow constructed substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings