Patent GB-229016-A (GB)
Title: Improvements in the production of welded wire fabric and apparatus therefor
IPC: B21F27/10
Filed: 1923-11-20
Abstract: 229,016. Pilkington Bros., Ltd., and Armstrong, A. Nov. 20, 1923. Wire fabrics.-In making wire fabrics bv electrically welding warp and weft wires at the crossing points, weft wire is fed axially from a spool &c. across a series of parallel warp wires arranged between a series of pairs of welding dies, by traction on its free end. A series of warp wires 3 are passed between a series of pairs of welding-dies 200, 201, weft wire 100, Fig. 10, is fed across the warp wires and a length severed therefrom and welded to the warp wires; the fabric is then fed step by step by a toothed drum 26 engaging the weft wires and by rubber covered rollers 80, 81, which also straighten the fabric, and lengths are cut off by a guillotine 83. The main shaft 1 is connected by reduction gear 20, 12, 22, 24 to a disc carrying a removable cam 25, which through a ratchet lever 27, 28 rotates the drum 26, an adjustable detent 31 being positioned so that after feeding, the drum can turn backwards through a small angle under tension of the warp wires to diminish the tension before being held by the detent. Cams with teeth of different or of varying heights may be used according to the pitch of the weft wires so as to obtain meshes of different sizes or patterned mesh. The cam disc may be connected to its gear wheel 24 by a spring-pressed pin 41 which may be withdrawn by hand so as to cut out the feed without stopping the main shaft when the weft wire is exhausted and may be re-engaged in the same relative position as that at which it was disengaged. The drum has a series of teeth to engage weft wires of pitch equal to or a sub-multiple of the pitch of the smallest mesh, the teeth being cut by tapered grooves to guide the warp wires. The rollers 81 are driven by chain gear 87 from the drum through a friction clutch, the peripheral speed of the roll 81 being normally slightly greater than that of the drum, and the friction in the clutch being so adjusted that the pull exercised on the fabric by the rolls 80, 81 is not quite sufficient to pull the weft wires from the teeth of the drum. The feed roll 80 which is mounted in spring- pressed pivoted housings 85 is carried in adjustable blocks 92 so as to vary the amount of bend given to the fabric in order to counteract any existing bend therein and so to straighten the fabric. The weft wire, which may be a fine wire, is fed through an adjustable spring-pressed nozzle 102, Fig. 10, by a finger or clamp 103, 104, Fig. 4, on a slide 124 which is traversed bv a screw 105 rotated alternatively in opposite directions by a chain 118, pinion 115 and sector 113, crank pins 112, 110 and connecting rod 111 from a shaft 108 which is connected by gapped gears 107, 106, to the shaft 1 so that the feed is stationary during welding. The slide is provided with adjustable friction blocks 132 engaging a bar secured' to the framing. The nut 123 in the slide is capable of rotating to limited extent determined by a pin 125 and slot 126 so that when the jaws have pressed back the nozzle 102 and are situated round the end of the weft wire, the jaw 104 is closed during the first part of the reverse motion of the screw, by teeth 127 on the nut engaging teeth 128 on the jaw. In order to vary the amount of traverse of the slide in accordance with the width of the fabric, the crank pin 110 is adjustable, and in order that the slide may always commence its stroke from the same position in the vicinity of the nozzle, the crank pin 112 is connected to the sector through an arcuate slot 122 so that the sector may be rotated to position the slide before connecting it to the driving shaft 1. The welding dies 200 which are secured in holes in a reciprocating head 203, press the weft wires into contact with the warp wires and the warp wires into contact with the lower dies 201. At the edges of the fabric the weft wire is pressed down by notched and slotted guides 7, which are placed in holes normally occupied by welding dies and which are cranked so that they may be turned to adjust the position of the weft wire relatively to the warp wires. The welding-dies are under the control of springs 217 and are pressed into their heads during the downward motion of the head. Just before the head completes its downward motion the weft wire is severed by a cutter 138, Fig. 10, passing over the face of the nozzle and operated by a lever 139 which engages a rod on the head. Welding is then performed, under control of a switch 209, Fig. 2, rotated by a chain gear from the main shaft 1. The dies are preferably insulated from their beams and any number of them may be arranged in parallel and connected to the secondary circuit of a transformer. In the event of a number of circuits being used, the switch may make and break the primary circuits in cascade. The tension of the springs 217 may be adjusted by screws 218 and any of the dies may be fixed in their raised positions by screws 221 passing through holes 220 so that fabrics with warp wires of different pitches may be made or fabric of reduced width or pattern fabric. According to the Provisional Specification the lower dies may be notched to guide the warp wires and the upper dies to guide the weft wire.