GB986325A - Improvements in wire binding machines - Google Patents

Abstract

986,325. Twisting wires together; angular bending; shearing. ROBERT BOSCH G.m.b.H. Oct. 10, 1963 [Oct. 11, 1962], No. 39916/63. Headings B3E and B3W. A hand applied, motor driven wire binding machine in which wire for binding concrete reinforcing rods together passes through a guide arm projecting laterally from the machine housing alongside the rods, is bent back into a " U "-shaped strap, severed from a storage reel, gripped by the ends and twisted together is characterized in that the guide arm carries a lever pivotable about an axis normal to the axis of the twisting tool which during its pivoted movement causes one section of the wire to be bent towards the twisting tool and about the rods. The machine comprises electric motor housing 10 and a gear housing 12 having a guide arm 13 to which is attached an " L "- shaped housing 14. With the housing 14 located under a pair of rolls 15, 16, binding wire 17 is advanced by a pair of rollers 57, 19 from a storage reel through a cutter block 55, along a channel 18 in the housing 14, in which it is retained by guide hooks 20, 21 until it projects over the end of the housing at which point the wire feeding is stopped and a rod 42, operated by a cam 43, depressed to effect movement of a spring-biased rack via a bearing block 44 and balls 49, which rotates a bending lever 22 via pinion 23 to bend the wire into a " U "-shape. The hooks 20, 21 which are pivotable about pins 45, 47 are deflected clear of the wire by engaging oblique surfaces 46 during depression of the rod 42 which also via a cone portion 52 thereon engages a cutter member 54, pivotally mounted on and co-operating with the block 55, to sever the " U "-shaped portion from the wire. The twisting tool comprises a disc 27 which is connected, by a coarse thread on the hub 29 thereof, with a nut 31 non rotatably mounted but axially displaceable on a driving shaft 26 on which is also mounted a disc 28. The discs have four radial recesses 29 which are in alignment during the feeding and bending operations to receive the strap ends. In operation the nut 31 is moved towards the discs by a cam-operated forked lever 32, against a return spring 35, thereby rotating the disc 27 relative to the disc 28 to clamp the wire ends against jaws 36. The twisting discs are subsequently driven by friction gearing comprising two bevel gears 37, 38. The gear 38 being urged against a spring into driving engagement with the gear 37 by a cam-operated bell crank lever 40. At the start of the cycle a conical projection 56 on the block 44 engages one of the disc recesses 29 to locate the disc shaft prior to feeding the wire. The grooved feed roller 19 is driven whilst the roller 57 is loaded thereagainst, to feed the wire, by a cam 58 on the end of the cam-shaft 33 and a crank arm 59. The transmission ratio between the armature shaft 39 and the shaft 33 is such that a complete operating cycle is carried out in one revolution of the shaft 33. In a modification, Fig. 7, wire 17 is fed past a bending mandrel 73, attached to a member 72, by an amount sufficient to form the straight leg of the strap and is then bent forwardly by a pin 74 of a pivoted lever 71 cam actuated via a push rod 77 into a " U " shape so that the end thereof engages open clamping jaws 78, 79 of a twisting mechanism. The jaws 78, 79 are pivotable at 81 on a shaft 80 and each has a lever arm 82, 83 engageable with an annular groove 84 of a bush 85 axially secured by a ball bearing in a tubular section 90 having trunnion pins 91, 92. The shaft 80 rests via a compression spring 86 against the bush and both the members are downwardly biased by a stronger second spring 88. The section 90 is raised by a forked lever 93 actuated by a cam 94 against spring 86, to effect closing of the jaws about the wire ends, when the jaws are closed preventing any further movement of the bush 85 on the shaft 80 the shaft is lifted against the spring 88. The shaft 80 is driven as before by bevel gears 96, 97 via an electrically driven gear train (not shown). A taper ended cam operated rod 99 laterally moves the member 72 and mandrel 73 clear of the wire prior to the twisting operation.