Patent GB-754980-A (GB)
Title: Improvements in and relating to wire strapping machines
IPC: B65B13/22
Filed: 1954-07-16
Abstract: 754,980. Wire strainers. BRETTELL, F. G. (General Strapping Corporation). July 16, 1954, No. 20803/54. Class 45. [Also in Groups XVII and XXII] A fully automatic wiring mechanism comprises means for looping wire by drawing it about and on to a package, a connecting device for the overlapping parts of the wire and means, operative on the wire on the near side of the device, from which side the wire is drawn away in looping for holding the one part and for tensioning the other part passed around the package by drawing said other part away from said device in the same direction as in looping. The binding-wire W, Fig. 1, is fed into a cage 3 ... 10 by rollers 1, 2 which are driven by an electric motor and controlled by a solenoidoperated clutch; the wire being wound from a reel controlled by a solenoid-operated magnetic brake. A micro-switch 17 or an electric eye simultaneously controls the drive of the feed rollers and. the brake of the reel. The arrangement is such that following each package binding, the rollers 1, 2 continue to feed wire into the cage until the loop operates the switch finger 18 to open same. The wire is fed about an'idler 11 to rollers 41, Fig. 4, carried by a ring gear 39 which engages rollers 34 journalled on bolts carried by the frame members 29, 33. If desired, the bolts are provided with eccentric sleeves 37 for adjustment purposes. The ring gear carries a wire tensioning device 49 ... 52 and is driven by a pinion 53 meshing with a brake pinion 54. The rollers 41 engage side plates 46 which are steadied by rollers 47. The pinion 53, Fig. 5, is adapted to be coupled to a spur gear 60 by a friction clutch 61; the gear 60 meshing with a spur gear 62 fixed to a shaft 63 carrying the drive pulley 67. The clutch 61 is operated by a bell-crank lever 72, 73 fast on a shaft 71, one arm of the lever being fastened to a chain 74 operated by a treadle 81, see also Figs. 6-8 (not shown). As the arm 73 is lifted it operates a lever 94 to release the clutch brake on the pinion 54 and simultaneously closes the clutch 61. The treadle also actuates a chain 95 for pulling the wire guiding finger 99 out of the path of the wire against the action of its spring 103. A worm 106 free on the shaft 59 is adapted to be coupled to a worm 105 fixed to the shaft 63 by a single revolution clutch 107. A second arm 116 fixed to shaft 71 is adapted to engage, by means of its roller 117, a cam 119 fast on the shaft 59 to stop same after it has turned through 90 degrees. When the ring gear completes a full cycle whilst the shaft 59 is stationary, a cam 120 operates a trip finger 110 to restart the shaft 59 and thus permit opening of the clutch 61 and closing of the clutch 91 by effecting depression of the arm 116 as by the roller 117. A drum cam 141, Fig. 11, is fast on the shaft 59 and provided with a groove 146 to receive a roller 147 which is carried by a pivoted arm 148 coupled to a slide 155. The slide passes through a head-piece 160, Fig. 16, embodying a wire feeding and tensioning gripper. The gripper comprises a jaw 183 pivoted to a fixed jaw 180 which is adjustably secured to a sliding block 182, see also Figs. 15, 17, 18, 19 (not shown). The jaw 183 is also pivoted to the block 182 by links 185, 186; the link 185 also being pivoted to a slide 188. The arrangement is such that reciprocation of the slide 188 in block 182 effects opening and closing of the jaw 183 whilst similar motion of the block 182 results in bodily movement of both jaws and their connecting linkage away from and back into the line of wire feed. A spring-actuated ball plunger 195 is fitted in block 182 and co-operates with depressions 196, 197 formed in the slide 188. Thus a short movement of slide 188 to the right whilst block 182 is held by a latch 192 will move the plunger 195 to the front end of depression 197 and cause links 185, 186 to slightly open jaw 183. If latch 192 releases block 182, continued movement of the slide. 188 will carry the block along with it to shift both jaws 180, 183 and the associated parts away from the line of wire feed. If slide 188 continues its movement to the right, the jaw 183 will be fully opened and the plunger 195 will engage depression 196 to lock the jaw 183 in the open position. Reverse motion of the parts will close jaw 183. The slide 188 is operated by a cam 198 on the shaft 59 and receives a roller 200 carried by a lever 202, 203. The lever carries a cross-head 207 that embraces a roller 208 secured to the slide 188. A plate 210, Fig. 18 (not shown), is fixed to the cross-head 207 and provided with a cam slot to control the latch 192. The gripper 180, 183 positions the wire relative to the severing and welding device and also slips the wire between the jaws of a first holding gripper that holds the end of the wire whilst the package is wrapped. The first holding gripper proper, Fig. 20, consists of a fixed jaw 214 and a movable jaw 216 which is pivoted to an actuating rod 219 operated by a cam 226 on the shaft 59. A second and like gripper, Figs. 23, 24 (not shown), grasps the wire after it has been wrapped and tensioned around the package; said gripper being actuated by a cam 241 on the shaft 59. The wire severing and welding unit, Figs. 25 and 28, includes a transformer bus-bar 249 which is horizontally and vertically reciprocated by arms 256, 265 respectively. The arm 265 is operated by a cam 268 on the shaft 59 and is coupled to the member 249 by a rod 271. The bus-bar is provided with a plate contact 250 that is fastened to a transformer unit 254 and brings the wire cutter and welding electrode 290 into and out of engagement with the wire, the unit 290 being pivoted to a slidably adjustable carrier 289 carried by the bus-bar. The unit is provided with a flexible conductor 303 of laminated copper and a copper alloy and hard steel insert 311, 312; the element 311 contacting the ends of the wire during welding and the element 312 serving as a blade. The unit also comprises a wire guide 314 and a cutting-block 315 having wire receiving grooves 322, 323, see also Figs. 26, 27, 29-31a (not shown). The blade 312 is adapted to swing to the right after the wire has been cut and allow the contact 311 to press the ends of the wire against a welding- plate 326 which is connected with the secondary of transformer 254. The welding period is controlled by a cam 328 fixed to the shaft 59 and serves to close a limit switch 329, Fig. 38 (not shown), in circuit with a timer 330. For details of the control circuit, Fig. 38 (not shown), should be referred to. The jaw 183 may be manually opened for inserting the end of the wire by a handle 343 and links 349, 207 and suitable connecting mechanism. Operation.-The wire is looped in the cage as at A and then passed through the tube 14, around rollers 11, 49, 50 and under finger 99 to the gripper 180, 183 which is opened by the handle 343. Power switch 335 is now closed and manual starter 338 operated to start feed rolls 1, 2; the wire being fed into the cage until it actuates the switch 17 to stop the feed. The treadle 81 is then depressed to start the members 39, 59 and withdraw the finger 99 from the path of the wire feed to permit the wire to be wrapped around the package. The gripper 180, 183 then feeds the wire through the gripper 214, 216 and the groove 322 in the cutting block 315 until the wire overlaps the block and underlies the welding-plate 326; whereupon gripper 214, 216 closes upon the wire-the finger .99 having returned to its original position. The gripper 180, 183 now opens to release the wire and the rotation of cam 59 ceases whilst the ring gear 39 wraps the wire around the package, the end of the wire being held by gripper 214, 216 and the body of the wire lying in the open gripper 234, 235 while passing under the cutting-block 315, the gripper jaw 216 and the finger 99. The ring gear is now stopped and the cam shaft rotated, causing the gripper 180, 183 to grip the wire and tension same. Next, the gripper 234, 235 grips the wire and the gripper 180, 183 opens. The cutter 290 now cuts the wire and presses its ends against the plate 326 for welding, whereupon both grippers 214, 216 and 234, 235 open. Specifications 553,788, [Group XVII], 640,345 and 640,442 are referred to.