Patent GB-1019878-A (GB)
Title: Bale strapping machine
Inventor: HEWLETT ARTHUR JAMES
IPC: B65B13/34
Filed: 1963-08-14
Abstract: 1,019,878. Bundling machines. ACME STEEL CO. Aug. 14, 1963, No. 32097/63. Heading B8C. [Also in Divisions B3, B6 and F2] A machine for joining metal strips by crimping a seal about their overlapping ends is capable of performing all the steps of feeding seal stock and automatically forming a channelshaped seal therefrom, moving a seal to the sealing position, feeding a binding strap from a source of supply through the channel-shaped seal to provide a length of strap sufficient to be looped around the box or other object to be bound with its free end extending through the seal in overlapping relation to the supply portion, then gripping the free end of the strap, then reversing the feeding means to draw the strap taut, then operating a sealing device to form a joint between the seal and the enclosed strap portions, cutting off the supply portion of the strap as the joint is completed while at the same time forming a new seal for the next sealing operation, then ejecting the sealed joint from the sealing device, and then feeding the seal which has just been formed to the sealing position in readiness for a new operation. General features (Fig. 2, 12, not shown).-The machine in general comprises a package support table 51, Figs. 2 and 12, strap feeding nip rollers 54, 55, sealing device 53, an anvil 56 and a seal former 57, and a shearing blade 58 to cut off the strap 50 when the joint has been formed. Forming metal seal (Fig. 12, 23, not shown).- The seal blank 52 is formed about the anvil 56 by a seal former 57, Fig. 23, comprising a pair of blades 57a, 57b. Seal stock in the form of a metal strip 80 is fed to the anvil from a horizontally disposed reel 81, Fig. 12, by a feeding dog 100 engaging holes 80a in the strip. A curved guide channel 85 serves to guide the strip to the forming position. Both the seal former 57 and the feeding dog 100 are driven by a main shaft 95 via various linkages shown in Fig. 23. A spring-loaded detent 118 serves to register the strip. The leading edge of blade 57a co-operates with a fixed member 87 to sever the correct amount of strip 80 to form a seal blank 52. The channel-shaped seal blank 52 is moved to the sealing device 53 on the anvil 56 which is mounted on a link 124 and lever 125, Fig. 12. A pneumatic cylinder 132 operates on the lever 125 to move the anvil to the sealing device 53. Sealing device (Figs. 11, 27, 29, not shown).- The sealing device 53, Figs. 27 and 29, comprises relatively movable bending jaws 145 pivoted on pins 146 extended between plates 147 carried by the machine frame. The jaws are operated via linkages 148, 149 and a lever 151 driven by the main shaft 95. The jaws 145 are first partly closed to bend the side walls 52e and 52f of the seal to conform with the tapered sides of the anvil 56 which is then withdrawn from the seal. The binding strap 50 is then threaded twice through the seal as it is looped around the package or box and the jaws 145 are then moved to the position where they are fully closed to form an interlocking joint between the seal and the enclosed strap ends as shown in Fig. 11. The jaws 145 operate in conjunction with a pair of shearing dies 153 which form the indentations 52d in the finished joint. The dies 153 are provided with parallel slots 153a engaged by the pivot pins 146. Each jaw 145 carries a roller 155 which engages the rear edge 153b of a die 153 to force the die forward against the seal as the jaws 145 are closed. Shearing blade (Fig. 30, not shown).-The shearing blade 58, Fig. 30, is actuated during the final stage of closing the jaws 145. This blade, with an inclined cutting edge 58a, is provided with slots 58b which are engaged by the pins 146. Rollers 156 carried by the jaws 145 engage the rear portion of the blade 58 to urge the blade forward. The blade is returned by pins 157 also mounted on the jaws 145. Sealed joint ejector (Figs. 27, 29, not shown).- The ejector comprises a joint engaging member 160, Fig. 27, having three fingers 160a, Fig. 29, which extend on opposite sides of the shearing dies 153 to bear against the completed joint and force it away from the sealing mechanism. The member 160 is moved forward by a lever 164 and link 170 driven by the main shaft 95 via extremity 151c of lever 151. Rollers 155 on the jaws 145 engage inclined camming surfaces 160c to positively retract the member 160 when the jaws 145 are moved to the fully open position. Strap gripping dogs (Figs. 29, 34, not shown). - The strap gripping dogs 62 which are adapted to securely hold the binding strap while it is being drawn taut around the box 60 are pivoted on the pins 146, Figs. 29 and 34, and are provided with cone-shaped projections 62b to grip the strap 50. The dogs are operated by a lever 180 mounted freely on the main shaft 95. A detent 188 pivotally mounted on a pin 171 carried by the lever 151 engages the lever 180 upon reverse rotation of the main shaft 95 and opens the dogs against the force of a spiral spring 184, Fig. 34. Release of the detent 188 to close the dogs 62 is under the control of a solenoid 197, Fig. 21 (not shown) through various linkages. Main drive (Figs. 12, 34, not shown). The main shaft 95 is moved angularly about its axis of rotation by a crank arm 200, Fig. 34, fixed to the shaft 95 and pivotally connected to the piston rod 202 of a pneumatic cylinder 203 having a fixed connection with another cylinder 204, Fig. 12. The piston rod 205 of the cylinder 204 is pivotally connected at 206 to the machine frame. Cylinders 203 and 204 therefore move as a single unit supported by their respective piston rods. Strap feeding and tensioning; reverse gearing (Figs. 13, 18, 20, not shown).-The strap 50 is fed by the driven serrated edged roller 54 cooperating with the idler roller 55, Fig. 13, through straightening rollers 216, guides 217, 219 and 230, and the channel-shaped seal blank held ready at the sealing section of the machine. The strip is then looped over the package 60 and between the pair of parallel rollers forming the support table 51 and threaded through the guides 70 so that the strap overlaps in the channel-shaped seal blank. The guide 70 is shown in cross-section in Fig. 18. A member 228, Fig. 13, operates a switch 320 if the strap buckles around the idler roller 55. The feed roller 54 is driven through reverse gearing, Fig. 20, by an electric motor 210 and belt 212. The reverse gearing comprises two parallel shafts 234, 246. The shaft 234 is driven by the belt 212 and has freely mounted thereon a gear 236 and a pulley 250. Two electromagnetically operated clutches having coils 243 and 257 each have clutch plate members splined to the shaft 34. Shaft 246 has fixed thereon the drive roller 54, a gear 245 meshing with the gear 236, a brake disc 263, a centrifugally operated switch mechanism 276 and a pulley 261. The brake disc 263 co-operates with an electromagnetically operated brake member 264 having a coil 265. The switch mechanism operates on switches 330 and 339. When the strap 50 has been looped around the package 60 and the free end gripped by the strap gripping dogs 62 (described above), the drive of the feed roller 54 is reversed to tension the strap before a joint is formed with the seal blank 52.  Operation.-Fig. 41 (not shown) illustrates the electric circuit for the machine and Fig. 39 (not shown) illustrates the pneumatic circuit. Closing switch 311 energizes rectifier 314 and motor 210. Closing switch 335 energizes a timer 333 which in turn energizes the feed clutch coil 257 (to feed the strap 50) via switches 320, 319 and 318. After a set period of time, the time switch 333 moves switch 318 to close contacts 318b, thereby de-energizing coil 257 energizing brake coil 265. Operating a foot switch 325, Fig. 12, closes contact 325b thereby de-energizing coil 265 and energizing coil 257 for further feed of strap 50. On release of foot switch 325, a switch 349 is momentarily closed to energize a relay 340 thereby closing relay contacts 340a, 340b, and 340d while opening relay contacts 340c. Closing contacts 340b energizes the solenoid 197 via contacts 339a to release the strap gripping dogs 62 to grip the leading end of the strap 50. Closing contacts 340d energizes the reverse clutch coil 243, to tension the strap 50. A rheostat 327 controls the magnetic force of the clutch to control the slip and therefore the tension of the strap. Slowing down of the shaft 246 causes the centrifugal switch 330 to close thereby supplying an extra shunt current to the coil 243 to increase the clutch torque and therefore the final tension in the strap 50. During tensioning, the centrifugal switch 339 shifts from contacts 339a to contact 339b, thereby de-energizing the solenoid 197 and energizing relay 338 to close relay contacts 338a, 338c and open contacts 338b. Relay contact 338a is a holding contact for relay 338. Opening relay contacts 338b prevents re-energization of the solenoid 197 when the centrifugal switch 339 returns to contact 339a. When switch 339 returns to contact 339a, the solenoid 292 of valve 290, Fig. 39, is energized via closed contacts 338c, causing piston 280 of cylinder 203 to extend thereby causing a new seal 52 to be cut off and formed around the anvil 56, causing the sealing device 53 to deform the previously formed seal and the enclosed strap ends to form a joint and causing the shearing blade 58 to shear the supply portion of the strap adjacent to the joint. The piston 280 at the end of its forward movement, operates reversing switch 336 to close contacts 336b, thereby de-energizing relays 338 and 340 to open relay contacts 338a, 338c, 340a, 340b and 340d while closing relay contacts 338b and 340c, and resulting in the energization of solenoid 294 of valve 291, Fig. 39. Closing relay contacts 340c energizes brake coil 265 and opening relay contacts 340d de-energizes tension clutch coil 243 to prevent rotation of the shaft 246 after the strap has been sheared. O