Cable duct and clamping bracket therefor

Abstract: The invention relates to a cable duct comprising an elongate duct part and a number of clamping brackets for fixedly clamping the duct part to a construction, wherein at least one clamping bracket fixes the duct part transversely of the length direction and leaves it free in the length direction and/or wherein the clamping bracket comprises a clamping part and at least one enclosing part protruding therefrom.

Description: The invention relates to a cable duct and a clamping bracket according to the preamble of claim 1. Such cable ducts and clamping brackets for clamping thereof onto steel constructions are generally available commercially. GB 2 114 820-A discloses a cable ladder, wherein the duct is supported and clamped according to a first embodiment with clamping plate. In a different embodiment shows the cable ladder supported by a frame. The clamping plate is replaced by a holding plate, wherein this plate has a hooked formation and embraces the flange of the duct. There is no fixation by clamping of the ladder relative to the support by these means. A problem with the known cable duct and clamping bracket is that it is not designed to multipurpose for any combination of clamping bracket and cable duct. The invention intends to provide a cable duct and clamping bracket therefor, which is multipurpose. Such a cable duct is obtained according to claim 1. A clamping bracket having a V-shaped wing, is well suited for any kind of cable duct for clamping the cable duct and still providing some degrees of free movement in the length direction of said duct. The degree of freedom in the length direction is needed in respect of the linear expansion of solid materials when there are temperature differences. They will core in long straight lengths of mounded cable duct in expansion which in terms of amount depends on the chosen material in the degree of difference between the highest and lower temperature. In order to prevent deformation of the cable duct route as a result hereof, the support construction and the manner in which the cable ducts are mounted thereon must be taken into account during assembly. According to the invention steel cable ducts are clamped onto steel constructions in a manner such that the cable ducts are fixed in width direction to the steel construction, but can slide freely in the longitudinal direction over said steel construction in order to prevent deformation if the cable duct as a result of thermal expansion. For cable duct in the material stainless steel and steel linear expansion can be determined at specific temperature differences. In order to prevent deformation an expansion space must be kept clear at mutual intervals between the cable ducts. The ducts can be joined together in situ using an expansion coupling the plate which is fastened on one side in the normal manner and is fixed on the other side by means of locking nuts. The cable duct route can hereby expand without deforming. The mutual distance between the support constructions on the route where the expansion occurs has to be adjusted depending on the anticipated load of the cable duct route and the type of cable duct used. The maximal span of a usual cable duct amounts to about 6 metres, depending on the load and embodiment. In order to allow the cable duct to slide freely over the steel construction in case of thermal expansion a fixing bracket according to the invention is applied which does fix the duct to the steel construction in width direction, but which allows the cable duct to move freely over the steel construction in length direction. The invention is further elucidated in the following description of embodiments with reference to the annexed figures. Figure 1 shows a perspective view of a cable duct according to the invention. Figure 2 shows a detail according to arrow II in figure 1. Figure 3 shows a clamping bracket applied in the construction of figures 1 and 2. Figure 4 shows a view according to arrow IV in figure 2. The cable duct 1 shown in figure 1 comprises an elongate duct part 2 which is clamped fixedly to a construction 4 by means of clamping brackets 5. Construction 4 is for instance a frame of a petrochemical installation. In petrochemical installations and the like in situ drilling for mounting cable ducts and the like is not allowed in respect of explosion hazard. Cable ducts of the present type are therefore fixed using clamping brackets. Duct part 2 is here drawn assembled from a number of elements, which are for instance mutually connected with expansion coupling plates 3 in order to enable the absorption of a certain variation in the longitudinal direction as a consequence of thermal expansion. Each element of duct part 2 is constructed here from two longitudinal beams 7 and cross beams 6 arranged therebetween. Longitudinal beams 7 protrude above the level of cross beams 6 so that a duct is formed in which cables and the like can be laid. As figure 2 shows, an outward pointing flange 8 is formed on the underside of longitudinal beam 7, which flange bears an end edge 9 which is folded upward. In the preferred embodiment shown here the bracket 5 comprises a U-shaped body 10 with a first leg situated at the top in the figure from which two wings 11 protrude laterally. Wings 11 have an end edge at a level which is at a distance from a surface of this leg directed toward the interior of the U. In the mounted situation this end edge is hereby at a distance from the supporting surface formed by construction 4 such that flange 8 can be received with clearance under this end edge. The upright end edge 9 of flange 8 falls beneath the bent form of wing 11 and is thereby enclosed laterally. Duct part 2 can thus slide over structural part 4 in length direction, but not in the transverse direction thereof. Bracket 5 is clamped fixedly on the upper flange of structural part 4 using a screw bolt 12. On its end protruding into the interior of the U the screw bolt 12 bears a cup ring 13, which ensures a good contact against the sloping underside of the flange of structural part 4. If different types of material are applied on top of each other, for instance hot-galvanized steel and stainless steel, an isolation strip 14 is placed between support construction 4 and cable duct 2, and likewise on the inner side of screw clamp 5, in order to prevent contact erosion.

Claims: Cable duct (1) comprising an elongate duct part (2) and a number of clamping brackets (5) for fixedly clamping the duct part (2) to a construction (4), at least one clamping bracket (5) comprises a wing (11) having a V-shaped cross section with an edge in the length direction for fixing the duct part (2) transversely of a length direction and leaving it free in the length direction. Cable duct (1) as claimed in claim 2, wherein the clamping bracket (5) comprises a clamping part and at least one enclosing part protruding therefrom, wherein the duct part (2) comprises a flange (8) with an end edge (9) folded upward thereon, and the enclosing part comprises the wing (11) which in the mounted situation encloses the end edge (9) with clearance. Clamping bracket (5) for a cable duct (1) as claimed in any of the foregoing claims, characterized in that the clamping bracket (5) fixes the duct part (2) transversely of the length direction with a wing (11) having a V-shaped cross section with an edge in the length direction. Clamping bracket (5) as claimed in claim 4, wherein comprising a clamping part and an enclosing part protruding therefrom and the clamping part comprises a U-shaped body (10) with a first leg from which at least one wing (11) protrudes laterally which has an end edge parallel to and at a level which is at a distance from a surface of this leg directed toward the interior of the U. Clamping bracket (5) as claimed in claim 4 , wherein the U-shaped body comprises a second leg lying opposite the first leg and provided with a threaded hole in which a screw element (12) is received. Clamping bracket (5) as claimed in claim 5 , wherein the screw element (12) bears a cup ring (13) on its end protruding into the interior of the U.

Inventors: BOER DIRK RENE, VAN LEEUWEN ISAAK MARINUS, BOER, DIRK RENE, VAN LEEUWEN, ISAAK MARINUS, Boer, Dirk René
Applicants: GOUDA HOLLAND BV, GOUDA HOLLAND B.V.
Application year: 2001
Main classification: F16B2
IPC codes: H02G3, F16B2