DEVICE FOR FIXING A STRUCTURE CABLE TO A CONSTRUCTION ELEMENT
The present invention relates to the field of cable utilization in construction sites. An application is found each time it is necessary to fix a cable subjected to traction effects to a structural element. The term "structure cable" as used herein also covers a bundle or group of individual cables substantially parallel to one another, each individual cable also being able to be composed of one. or several elementary strands. An important field of application of the invention is that of the fixation braces that serve to support the boards of the cable-stayed bridges. A fixing brace consists of a bundle of braided cables anchored at their two ends by means of anchorage blocks. In general, the anchoring block has, for each braided cable, a hole through which the braided cable is worn by means of a truncated cone-shaped snack. In a current mode, the deck of the bridge is made of concrete, and the anchorage block rests against a plate located in the lower mouth of a formwork tube that crosses the concrete deck. The fixing bracket is threaded into this formwork tube to reach the anchorage block. At the upper end of the formwork tube is connected a guide tube that contains a diverter that allows on the one hand a slight deviation of the braided cables so that they have sufficient mutual separation at the level of the block to carry out the anchoring, and on the other hand the deflection efforts to which the fixation strap can be subjected. Beyond the guide tube, another protective tube ensures connection to the main cover of the fixation strap. This system has many numerous parts, and involves many changes in diameter in the apparent part of the fixing strap that emerges from the board, which is not desirable especially for aesthetic reasons. On the other hand, the formwork tube must be placed with great precision, which complicates the execution of the concrete board. In other embodiments, the anchoring block is retained in a fork joined to the work by means of a joint. The fork must have a configuration that gives access to the anchorage block in order that the individual anchorage of the braided cables can be carried out and the means that protect the anchorage area against corrosion can be placed. In these embodiments, the anchorage block is housed between the sides of the fork, and its front face abuts against a fork head traversed by the braided cables. In order to accommodate the block, the space between the sides of the fork must have a sufficient length and width, so that the fork has a relatively large volume and thickness. An object of the present invention is to simplify and lighten the fixing of the cable to the work. The invention thus proposes a device for fixing a structure cable to a construction element, comprising an anchoring block provided with footwear means comprising the strands of the cable, and a fork articulated on the structure element and presenting in the direction of the cable. cable a head crossed by a hole in which the cable is hooked, the fork has a suitable configuration to retain the anchorage block when traction is exerted on the cable. According to the invention, the anchoring block is at least partly engaged in the bore through the head of the fork, this hole has a bore which receives a complementary thread formed at the periphery of the anchorage block and / or in a stop member in order to retain the anchored block. The face of the anchorage block, or of the stop member, on the head of the fork allows to reduce the fork dimensions, especially in length and thickness thanks in particular to a better transmission of stress between the cable and the construction element. It is especially the use of more compact pieces that allow a better continuity effect between the cable and its means of connection with the work. In the particular modes of the device: the fork has two flanks that extend from the head to an opposite end of the fork where they are traversed by a hinge axis in the structure element, an access to a rear side of the anchorage block, transversely in the direction of the hinge axis, is left between the sides of the fork; a cable protection tube is connected over the fork head; - a gasket that provides an elastic relation is interposed between the protective tube according to the previous paragraph and the head of the fork, in order to center the protective tube on the head of the fork; The cable consists of braided cables each protected by an individual cover of plastic material that is interrupted in a chamber formed in front of the anchorblock and crossed by the braided cables, so that the braided cables are shod in the anchorblock in a portion where they are devoid of the sheath, the chamber is filled with a protective material, and a part at least of the wall of the chamber is attached to a piece screwed into the bore formed in the head of the fork, said part can form a stop member against which the anchor block is applied; - the front side of the chamber according to the previous paragraph is closed by a gland-type sealing system comprising at least two rigid plates traversed by the braided cables, at least one elastic cushion placed between two plates and pressure means of the cushion between the plates; the pressure means according to the preceding paragraph comprise a piston that rests against the outer plate of the sealing system and is connected to a thread eng in the bore formed in the fork head; the chamber according to any of the three preceding paragraphs extends at least partly towards the inside of the fork head; the camera according to any of the previous four paragraphs communicates with another camera located on the back side of the anchorblock, filled with the same protective material and closed by a cape. Other features and advant of the present invention will appear in the description hereinafter of examples of non-limiting embodiments, with reference to the accompanying drawings, in which: Figure 1 is a schematic longitudinal sectional view of a fixing device according to the invention. Figure 2 is a perspective view of a fork of the device. Figure 3 is a sectional view showing an example of anchoring and securing means of a tie rod in the device of Figure 1. Figure 4 is a diagram of an organ that is part of a variant of the means of protection . The invention is illustrated hereinafter in its application to tiered bridges. The device shown on the drawings serves, for example, to fix the lower end of a strut on the bridge panel. The reader will appreciate that a similar device could be used at the upper end of the strut, and more generally to perform the fixation of other types of structure cables used in construction techniques. The brace shown on Figure 1 is composed of a bundle of substantially parallel braided cables 10. In the example shown, each braided cable is of a greased sheath type or waxed sheath. It consists of a thread that works in a fraction, formed by a braided assembly of metallic filaments, submerged in a protective material such as grease or wax, and contained in an individual cover made of plastic material such as a high density polyethylene (HDPE). The ends of the braided cables constituting the cable are shod in an anchor block 12 retained in a fork 13. The fork 13 is shown in Figure 2.
This has a head 14 traversed by a punched hole
15 coaxial to the tie. At its opposite end, the fork 13 has two arms 16 carried by the flanks 17 that extend from the head 14. The fork 13 is installed with its two arms 16 arranged on one side and the other of a support 18 attached to the board ( Figure 1) . A horizontal articulation shaft 19 passes through the arms 16 of the fork and the support 18 in order to articulate the fork 13 with respect to the board. The anchoring block 12 is hooked and screwed into the drilled hole 15 present in the head
14 of the fork. It has thus a general cylindrical shape, whose periphery has a fillet 21 complementary to the perforation present in the head 14. An optional ring 27 also has a complementary fillet 37 is screwed into the drilled hole
15 ahead of the anchoring block 12. This ring 37 contributes to hold in place the block 12 resting against it. In a variant of mode, the block 12 is not threaded, but only the ring 27 which will then be of sufficient length to have the tensile force. Accordingly, it is not necessary to provide that the flanks 17 of the fork 13 have a sufficient length and spacing to accommodate the assembly of the anchoring block and allow easy access thereto. In addition, a good transmission of the forces in the fork 13 allows it to be constituted lighter than in the previous devices. As shown in Figure 3, the individual sheath of each braided cable 10 is interrupted in front of the front face of the anchoring block 12. The bare end of each braided cable 10 passes through a hole provided in block 12, ending with a mouthpiece in the form of a truncated cone on the rear face of the block 12. On this rear face, anchor pincers 24, of truncated conical shape complementary to that of the embouchure, is placed around a braided cable in order to fit in the block 12. To protect against corrosion the bare ends of the braided cables 10, a chamber 25 filled with a protective material not represented as a wax or resin is disposed on the front side of the anchorage block 12, so that the interruption of the individual cover of each braided cable is placed inside this camera. The chamber 25 is delimited laterally by a cylindrical wall 26, for example welded on the threaded ring 27. On the opposite side of the block 12, the chamber 25 is closed by a packing-type sealing system (see European Patent 0,323,285). In the example shown, this sealing system comprises three rigid plates 28a, 28b, 28c, for example made of high density polyethylene, crossed by holes placed to pass the braided cables 10, and two elastic cushions 29, for example foam , sandwiched between the rigid plates 28a, 28b, 28c and equally pierced by the sheathed braided cables 10. Filled rods 30 extend into the chamber 25 between the anchoring block 12 and the sealing system. These rods 30 pass through the plates 28a, 28b, 28c and the cushions 29 and receive the nuts 31 beyond the sealing system and / or back of the block 12. A spacer 32 is arranged in the chamber 25 for example around the threaded rods 30, to define the spacing between the front face of the anchoring block 12, and the innermost rigid plate 28a. The pressure of the nuts 31 from the front side and / or the rear side of the device then makes it possible to compress the cushions 29 to make the seal in front of the chamber 25. One or more channels, not shown, are provided in the anchoring block 12 to make communicating the camera 25 with another camera 34 located on the rear face of the block. This chamber 34 is delimited by a cap 35 that covers the back side of the block 12 in a hermetic manner. The cable 35 fastened with bolts on the block 12 as shown, or also screwed into the punched hole 15 of the fork. The cap 35 has an injection hole 36 for the protective wax. After the injection, it comes to fill the chamber 34, the interstices left free in the anchoring block 12, as well as the chamber 25 in which the individual sheath of the braided cables 10 is interrupted, in order to protect against the corrosion the exposed metal parts of the braided cables. To thread the braided cables 10 into the anchoring block 12 previously screwed onto the fork head, put in place the shoe tongs 24, the threaded rods 30 and the capote 35 and proceed to the injection of wax, it is necessary to access to the rear side of the block, between the flanks 17 of the fork. Some space is left available behind the block 12 and the cap 35 as shown in Figure 1. But the incidence of this space on the dimensions of the fork is reduced by the fact that the block 12 penetrates the head of the fork 14 where it is screwed, and that the sides 17 of the fork are traversed in the hinge axis 19, thus leaving an access to the rear side of the anchorage block transversely to the direction of the hinge axis. The arrangement of the fixing device can also make it possible to disperse the guide tubes and deflectors used in the fixings of the usual tie rods. The articulation of the fork 13 on the board allows tolerating certain movement of the tie. To leave the braided cables diverging towards the anchorage block 12, the chamber 25 and the sealing system can be lengthened, which facilitates the conception of device assembly, especially the fact that the chamber 25 can be extended, at least in part , in the perforated hole 15 of the fork head. After having installed the fork 13, the anchoring block 12, the braided cables 10 and their tongs 24, the sealing system and the cap 35, and having proceeded to the injection of wax, a protective tube 40 is put in place. on the portion of the brace emerging from the anchorage block and the chamber 25. This tube 40 can be connected continuously on the head of the fork 14, with interposition of a seal 41 as shown in Figures 1 and 3. tube 40 ensures continuity with the sheath containing the bundle of braided wires in the current part of the strut. It may have water evacuation channels not shown. It also serves to protect the braided cables 10 against traffic accidents and the lane at the base of the brace. When the seal 41 has a toric shape with a tubular section as shown, it performs a self-centered elastic articulation between the fork and the shoulder strap. Figure 4 illustrates a mode variant in which the pressure means used to compress the cushion (s) 29 between the rigid plates of the sealing system comprise a piston 44 defined by an internal annular flange of a piece 45 in general cylindrical shape. Towards the anchoring block 12, the part 45 terminates by an externally threaded portion 46, complementary to the perforation 15 formed in the head 14 of the fork. In this way, by screwing the piece 45 on the fork, it rests on the outer plate 28c of the sealing system, which compresses the cushions 29 to perform the hermeticity if the inner plate 28a comes up against one or more braces placed in the chamber 25. It is especially possible to provide a cylindrical strut placed between the bundle of strands and the piece 45. Furthermore, the piece 45 or this brace can serve to laterally delimit the chamber 25 containing the protective wax. On the opposite side of the anchoring block, the part ends, for example, by a portion 47 internally threaded so as to be connected over the current part of the external sheath of the strut. The supplementary protective tube 40 of FIG. 3 can thus be dispensed with.