CONNECTION APPARATUS

Abstract: A cable trunking joint comprising : two sections of cable trunking (3) and a connector member (2) adapted to receive the respective ends of the trunking sections, and characterised by at least one wedge member (1) adapted to be driven between one end of the connector member and the trunking section fitted therein, so as to urge co-operating surfaces (7) of the connector member and trunking section firmly into frictional engagement.

Description: This invention relates to apparatus for connecting adjacent lengths of cable trunkings. Conventional lengths of cable trunking are generally cuboidal, that is to say approximately in the form of a rectangular parallelepiped; one face of the cuboid is a removable cover, allowing access to the cables contained within the trunking. US-A-1782779 discloses connection apparatus in which a conduit is held within a connector member by means of a screw which extends through the connector member into the space between the inner surface of the connector member and the conduit. The screw is dimensioned such that as it is advanced into the space, it urges apart the inner surface of the connector member and one side of the conduit until the opposite side of the conduit contacts the opposite inner surface of the connector member. In this way, the conduit is held in position by the frictional engagement of the contacting surfaces of the conduit and connector member. A defect of this apparatus is that the screw may deform the side of the conduit. This reduces the rigidity of the conduit. It is an object of the present invention to provide a structurally rigid joint between two lengths of cable trunking which may be easily assembled. According to the invention, apparatus for connecting together two lengths of cable trunking comprises a connector member, adapted to receive the respective ends of the lengths of trunking and characterised in that it comprises at least one elongate tapered wedge member, adapted to be driven between one end of the connector member and the lengths of trunking fitted therein with the taper extending lengthwise along the trunking, so as to urge co-operating surfaces of the connector member and the length of trunking firmly into frictional engagement. Such an arrangement serves to secure the trunking length firmly within the connector member, thus forming a rigid joint. In practice both trunking lengths will normally be secured within opposite ends of the connector member by means of respective wedge members. The invention thus has the advantage of reducing the deflection occurring at the connector positions in trunking beams. Preferably the connector member has at each end substantially the same cross-sectional shape as the trunking lengths, although its dimensions must, of course, be slightly larger so that the trunking lengths fit inside the connector member. The shape and dimensions of the connector member can readily be selected to suit the particular form of trunking lengths which it is designed to join together. The wedge member may have at least one ridge extending parallel to the thin edge thereof. Preferably at least one face of the connector member has at least one inwardly-projecting formation, preferably a louvred indentation, which is capable of engaging with the wedge member ridge or ridges so as to secure the wedge member against withdrawal from between the said face of the connector member and the respective trunking length. This provides a tight enclosure to connect the trunking lengths. Conveniently, to ensure engagement, the louvred indentations at the middle of the connector member are more deeply indented than those at the ends. It is preferable that the increase in depth matches precisely with the slope of the wedge member. The louvres are inclined inwards towards the central transverse plane of the connector member, all the louvres at one end of the connector member thus being formed in the opposite direction to those at the other end of the connector member. Means may be provided within the connector member to prevent the trunking lengths extending any further than half-way along the connector. For example, a stop piercing may be formed extending into the conductor at the middle thereof. One embodiment of the invention will now be illustrated, by way of example, with reference to the drawings in which Figure 1 is a perspective view of a connector member, a pair of wedge members and the ends of two lengths of trunking to be joined together, and Figure 2 is a longitudinal section through the connector member of Figure 1 with the wedge members and lengths of trunking inserted therein. In Figure 1, each length of trunking 3, only part of which is shown, is formed of sheet metal bent into cuboidal shape with one open side, the edges 7 of the sheet metal bounding the open side being curved inwards as shown to form flanges which define longitudinal corner channels. The connector member 2 is also formed from sheet metal, of approximately the same shape of cross-section as the lengths of trunking, but is dimensioned so that the ends of the lengths of trunking can be slid into it from opposite ends. The face of the connector member 2 opposite the open side has indented louvres 5 formed therein, the louvres on one side of the central transverse plane of the connector member 2 being directed in the opposite direction to those in the other side. Ten louvres or more may be formed in the connector member 2. To prevent the length of trunking 3 sliding more than half-way through the connector member 2, a stop piercing 6 is provided, extending into the connector member 2 at the mid-way point. This ensures that the connection is formed at the centre of the connector member 2. Each wedge member 1 is a nylon tapered drift piece, having four ridges 4 formed in one face thereof and extending transversely across it. Figure 2 shows the assembled connected joint. To form the joint, one of the lengths of trunking 3 is slid into the connector member 2, with the open faces of the length of trunking and connector member in register, until it reaches the stop piercing 6. A wedge 1 is then inserted between the length of trunking 3 and the louvred face of the connector 2 and is hammered into position. The same procedure is then followed for the other length of trunking 3 to form a rigid joint. The inturned flanges of each length of trunking 3 are pressed against the complementary internal surfaces of the coreesponding flanges of the connector member 2, and the reaction force provides a friction fit. The pitch of the ridges 4 is set so as to provide a Vernier effect with the louvres on the connector member 2. Thus, the pitches of the ridges 4 and louvres 5 differ slightly. As the wedge 1 is hammered into place, a slight ratchet engagement of small increments locks the wedge 1 into position at any point during the insertion. The depth of the louvres 5 increases progressively towards the centre of the connector member 2 to allow for the decreasing width of the wedge 1. This ensures that the lengths of trunking 3 are parallel to one another and to the connector member 2. Following assembly and installation the open sides of the trunking lengths and connector members can be closed by co-operating covers, but such covers do not form part of the present invention and have not been illustrated. The use of tapered elongate wedges in securing the connector member provides an even pressure which maintains the electrical earth continuity between lengths of trunking. As the securing force of the wedge is not concentrated in any particular region, it avoids local deformation and consequent reductions in rigidity. By providing a plurarity of ridges on the wedge, a series of locking positions of the joint ensure that the connection member holds the trunking lengths in place, irrespective of the distance the wedge has been driven. The use of this type of joint construction is not restricted to joints between lengths of trunking of the type described.

Claims: Apparatus for connecting together two lengths of cable trunking, comprising : a connector member (2), adapted to receive the respective ends of the lengths of trunking (3) and characterised in that it comprises at least one elongate tapered wedge member (1), adapted to be driven between one end of the connector member and the length of trunking fitted therein, with the taper extending lengthwise along the trunking, so as to urge co-operating surfaces (7) of the connector member and the length of trunking firmly into frictional engagement. A cable trunking joint comprising : two lengths of cable trunking (3) and a connector member (2) receiving the respective ends of the trunking lengths, and characterised by at least one elongate tapered wedge member (1) driven between one end of the connector member and the trunking length fitted therein, with the taper extending lengthwise along the trunking, so as to urge co-operating surfaces (7) of the connector member and length of trunking firmly into frictional engagement. A joint according to Claim 2, in which, at each end, the connector member (2) has substantially the same cross-sectional shape as the corresponding lengths of trunking (3), but is slightly larger. Apparatus according to Claim 1, or a joint according to Claim 2 or 3, in which the connector member (2) is generally cuboidal with one open side. Apparatus according to Claim 1 or 4, or a joint according to Claim 2 or 3, in which the wedge member (1) has at least one ridge (4) extending parallel to the thin edge thereof. Apparatus or a joint according to Claim 5, in which at least one face of the connector member has at least one inwardly-projecting formation (5) capable of engaging with the wedge member ridge or ridges (4) so as to secure the wedge member (1) against withdrawal from between the said face of the connector member (2) and the respective length of trunking (3). Apparatus or a joint according to Claim 6, in which there is a plurality of the said formations (5) and ridges (4), whose pitches differ to produce a Vernier effect between the wedge (1) and the connector member (2). Apparatus or a joint according to Claim 6 or 7, in which the inwardly-projecting formations (5) toward the middle of the connector member (2) are progressively more deeply indented than those at the ends. Apparatus or a joint according to Claim 6, 7 or 8, in which the inwardly-projecting formations are louvred indentations (5) of which the louvres are inclined inwards towards the central transverse plane of the connector member. Apparatus or a joint according to any preceding Claim, in which means (6) are provided within the connector member (2) to prevent the lengths of trunking (3) extending any further than half-way along the connector.

Inventors: COOK, EDWARD WILLIAM, WEBB, STEVEN PAUL
Applicants: WALSALL CONDUITS LIMITED
Application year: 1988
Main classification: H02G3
IPC codes: H02G3