Patent GB-389561-A (GB)
Title: Improvements in and relating to the manufacture of wire mesh and the like for concrete reinforcement and other purposes
IPC: B21F27/10
Filed: 1931-11-16
Abstract: 389,561. Welding wire fabrics. HUME STEEL, Ltd., Kinnear House, King Street, Melbourne, and COSGROVE, C., 141, Richardson Street, Middle Park, both in Victoria, Australia. Nov. 16, 1931, No. 31718. [Class 83 (iv).] In making electrically welded rectangular wire mesh for reinforced concrete &c. the longitudinal wires are intermittently advanced over a rigid contact plate which co-operates with a series of laterally spaced vertically reciprocating electrodes to weld successive cross wires thereto, when they are positioned and held on the longitudinal wires above the contact plate. In one form, the longitudinals 7 are fed from braked spools through externally screwed guide sleeves 8, Fig. 12, which are detachable to suit the diameter of the wires, and preferably also through intermittently operated sand blast to clean the parts to be welded. The ends of the wires are secured to a drum 6, preferably collapsable, rotated intermittently by ratchet levers 28 which are driven by connecting rods 26, arms 23, and link 22 from a reciprocating shaft 17. This shaft has an abutment 16 and a frame 19 with an abutment 18 by which it is reciprocated by a pin 14 in a disc 11 on a shaft 12 geared to the driving shaft. The connecting rods 26 are pivoted to hollow blocks 27 slidable on the ratchet levers 28 and held thereon by spring-pressed serrated blocks. In order to reduce the angular movement of the drum automatically as the diameter of the mesh on the drum increases and so obtain a constant feed, the blocks are connected to a shaft 31, Fig. 9, having rolls 29 resting on the roll of fabric. The ratchet levers may have a number of spring pawls 34 of different length so as to prevent lost motion or a number of similar pawls engaging a ratchet wheel 33 having sections with staggered teeth. Stop pawls 36 are also provided. Lateral wire 39, Fig. 3, is fed through a straightener 56 and guide 60 Fig. 12, by a pair of chains or bands 41 which are driven by spur gear and mitre gear 50b from a shaft 50a chain driven from the shaft 12. The grippers on the chains 41 consist of spring- pressed serrated jaws 47, Fig. 5, connected to cheeks 44 which arc united by cross members 46 and move along guides 52. The guides are adjustable by screws to suit the size of wire and have tapered ends. The wire is fed over a cross-member 59 and a length is cut off by a lever 58, 61, operated by a cam 66a, Fig. 16, on the shaft of a continuously driven pulley 68. For this purpose the end 62 of the lever arm 61 is provided with a spring pressed plunger 63, which is normally held retracted by a spring- pressed locking pin 71 engaging a groove 69 in the plunger. When a cam 78, Fig. 3, on the shaft 79 engages a lever 77 the locking pin is withdrawn by a rod 76 and lever 74 so as to release the plunger. After cutting, the plunger is reset by the cam surface 66b. The wire is then transferred to ramps 86 by a V-shaped member 81 on a lever 82 linked to the lever 58, and it slides down on to the longitudinal wires, hinged bars 113 restraining excessive forward movement. Levers 88 having shoulders 101, Fig. 15, to engage the contact plate 107 and faces 102 to engage the wire now push the wire on to the contact plate so as to hold it against similarly shaped weighted levers 103. The levers 88 are operated by a pin 94 on the disc 11 through weighted lever 93, and levers 92, 91. Welding is then performed by spring-returned electrodes 121 operated by the cam shaft 79. The electrodes may be arranged in three groups, each connected by strips 123 to a separate single phase transformer 124. In using three phase current the primaries are connected thereto in delta fashion and the secondaries in star fashion, one secondary to each phase and the neutral point to the contact plate 87. The electrodes may have inclined grooves engaging pins so as to give a partial rotation to remove dirt from the wires. The current is controlled by an automatic switch operating in timed relation with the cam shaft. For this purpose alternate electrodes of each group are connected to the opposite terminals of their transformer. Spring-opened switches 128 associated with the various groups of electrodes are successively closed by a series of bars 127 on a carrier secured to the cam shaft, so that a pair of electrodes of each group operate simultaneously with equivalent pairs of the other groups. The welding current passes successively through the adjacent junctions of each group and is switched off while the electrodes are in contact with the wires In a form in which the completed mesh is delivered from the machine in flat condition, the feed is effected by a series of metallic brushes 136, Fig. 19 on a frame 131, which is reciprocated from the shaft 17 by a rod 137 adjustably connected to a lever 138, and arms 141 and rods 142 engaging gudgeon pins on bars 144 secured by apertured brackets 146 to the frame. In order to lift the frame prior to effecting the return motion slide bars 169 passing through the brackets 146 are connected to arms 168, one of which is mounted on a shaft 166 carrying an arm 164 connected by a rod 163 to an arm on a shaft 162 carrying the arm 161. This arm is connected to a forked lever 157 movable on a loose block 159 on the shaft 12 and having a roller 156 engaging a grooved cam 151. The forward movement is effected after a spring-pressed catch 176 has been removed from contact with the rear of a collar 17a on the shaft 17 by a projection 171 on the disc 11. The catch is then raised to engage the front of the collar and the frame is now raised by the action of the cam groove 154. The catch is then lowered by a projection 171a on the disc and the frame is reciprocated rearwardly and then lowered by the portion 155 of the cam. The mesh is supported beneath the frame by a number of longitudinal bars.