Patent GB-738189-A (GB)
Title: A method for and apparatus for splicing webs, especially for wrapping machines
IPC: B65H19/18
Filed: 1953-02-20
Abstract: 738,189. Feeding webs. AMERICAN MACHINE & FOUNDRY CO. Feb. 20, 1953 [July 26, 1952], No. 4771/53. Class 100(1). Apparatus for splicing a reserve web to a web being fed includes a support for supporting a length of the reserve web such that its leading end is adjacent a length of the web being fed, means for cutting the length of reserve web from its leading end and for cutting the length of web being fed from its trailing end, and joining means for bringing the first and second lengths into contact with each other and securing them together while they are stationary. As shown, rolls R1 and R2, Fig. 1, of web are carried, on arbors 30 and 32, by a member 28 supported on a shaft 26. The shaft 26 has cutaway portions 180 degrees apart for engagement with a spring-pressure pin, not shown, slidable in a bracket 42 and actuated by cable 46 to release the pin when it is desired to rotate the member 28. As shown, a web W1 is being fed to a wrapping machine F, while a web W2 unwound from the roll R2 is in reserve. The web W is drawn by feed rollers 82 and 84 over a table 62 between guides 64 laterally adjustable on a screwed shaft 68, between guides 95 and 96, and then around guide roll 72 and a loopforming roller 74. Mechanism, for splicing the webs W1 and W2 is put into operation automatically on actuation of a sensing device 100. The device comprises a roller 108 carried on an arm 102 pivoted to a lug 106, the roller 108 normally resting on the upper surface of the web W1. The web W1 is supported by slotted plates 110 beneath the roller 108, such that when the end of the web W passes from beneath the roller 108, the arm 102 drops through the slot in the plate 110, thereby causing operation of an electric switch. The leading end of the web W2 is clamped by a device 122 carried by levers 126 freely mounted on a shaft 128. In a preferred embodiment, the webs are spliced by heat sealing in which case the webs are preferably of waxed paper or material capable of being fused by heat. Mechanism for heat sealing the webs comprises a device 180 carried by arms 184 and having a heated plate 186. The arms 184 are fixed to a shaft 164 rocked by a cam, not shown, on a shaft 170 engaging a lever, not shown, secured to the shaft 164. The webs are held during splicing by clamp bars 198 and 200 which engage grooves 117 and 123 in plates 116 and 120 respectively. The bar 198 is carried by cam-operated levers 204 and the bar 200 by brackets 208 secured to the levers 204, such that during rotation of the shaft 170 the levers 204 are raised and lowered. Links 216 attached to the levers 204 have a pin-andslot connection with pivotally mounted latch arms 222 engaging in notches 226 in the hubs of levers 228. The levers 228 have slots 230 engaging the ends of the roller 74 which slides in guides 78. The shaft 170 is driven through a known one-revolution clutch engaged by operation of a solenoid, such that the shaft 170 performs one revolution on energization of the solenoid. In operation, the device 122 is manually swung into operative position as shown in Fig. 1, and the leading end of web W2 is clamped thereto, this movement also causes downward movement of the levers 228 and roller 74 to form a loop in the web W1. The electrical circuit, Fig. 15, is then energized by depression of button 293, switch 114, operated by the roller 108 which rests on the web W1, being in the position shown. Current then flows through the normally open contact of the switch 293, through the normally closed contact of switch 114, and through coils of a relay 281, thus causing closure of contacts 299. Current then flows through switch 285 and relay 281 until the switch 285 is opened by a rotating cam 283. When the roller 108 drops, due to absence of the web W1, the switch 114 is closed to energize a solenoid 252 which permits rotation of the shaft 170, Fig. 1, through the one-revolution clutch. Thus levers 204 are lowered to effect clamping of the webs by the bars 198 and 200, while links 216 release latch arms 222 and thus unlock the levers 228. Springs 232 then raise the levers 228 to release the loop of web stored by the roller 74 ; the loop being used by the wrapping machine during the splicing operation. A cam 168 on the shaft 170 then rocks, through a lever 162 and link 160, a lever 158 secured to a shaft 156, thereby actuating a knife 150 secured to a lever 154. The knife 150 passes through a slot 125 in the device 122 and between bevelled faces 119 and 121 of the plate 116 and table 62, thus cutting the leading end of the web W2 and the trailing end of the web W1. While the knife 150 retracts after cutting the webs, the arms 184 are first lowered to effect heat sealing of the two webs and then raised. The webs are then unclamped by raising of the levers 204 to disengage the clamp bars 198 and 200. After reloading of a fresh roll in place of the exhausted roll W1, the device 122 is retracted to clamp the leading end of the fresh web and is then returned to the position shown in Fig. 1, thus lowering the arms 228 to form a loop around the roller 74. In a modification, Fig. 16 (not shown), a roller, mounted on a spring-pressed arm, senses the diameter of the expiring roll so as to operate a switch, the equivalent of switch 114, Fig. 15, when the roll R1 is depleted. A reciprocatory knife, operated by a cam, is provided for cutting the end of the expiring roll, while a fixed knife co-operates with the equivalent of the device 180 to cut the leading end of the fresh roll. In either embodiment, the web ends may be spliced by a device 480, Fig. 19, which comprises a series of pins 487 and 465 carried respectively by a plate 482 and a table 463. The pins 487 and 465 punch holes in the overlapped webs W1 and W2, such that the two webs become secured together by barring of the web around the holes. Alternatively, adhesive may be applied to the leading end of the fresh web through a duct in the clamping device 122, Fig. 1, such that the two webs may be spliced together on the application of pressure, by the device 180, to the webs.