Patent GB-807184-A (GB)
Title: Apparatus for applying transfer labels to packaging materials
IPC: B65C9/18
Filed: 1957-03-28
Abstract: 807,184. Photo-electric control. DENNISON MANUFACTURING CO. March 28, 1957 [April 11, 1956], No. 10205/57. Class 40 (3). [Also in Group XVI] Apparatus for applying transfer labels, by heat and pressure, from a base stock 18 carrying the labels and having registration apertures, on to a web of packaging material 14, comprising a rotary die wheel 60 having a heated sectorshaped radially enlarged portion, a back-up roll 16 having a resilient surface, and means operating at each cycle of rotation of the die wheel for pulling rearwardly on the base stock in advance of the die wheel and establishing a definite length of base stock between one of the registration apertures of the stock and the die wheel. The apparatus includes a frame 24 (Fig. 1) comprising side frame plates 26, 28 joined to frame plates 30, 32. The web of base stock 18 is drawn from a roll 38 and passes under a guide roll 40, between the resilient back up roll 16 and die wheel 60, under a guide roll 44 and over a rotated tensioning drum 48. The web of packaging material 14 is also guided between the roll 16 and wheel 60 and then passes to a packaging machine 12. The shaft 52 (Fig. 3) of the drum 48 is rotated by a motor 74 through a speedreducing unit 78, sprocket and chain arrangement 82, 84, 86 and belt and pulley arrangement 90, 92, 94. The chain 52 is supported between the side frame plates 26, 28 and the drum 48 includes a rubber core 54. A leaf spring 56 co-operates with the core 54. Rotation of the drum 48 thus ensures correct tensioning of the web 18. The die-wheel assembly 60 is mounted on a hollow shaft 62 journalled in a bearing 64 in the frame plate 28 and is rotatable on a fixed axle 66 secured to the frame plate 26. The drive for the shaft 62 is derived from the driven shaft 88 through gears 96, 98 and 102, the latter being rotatably mounted on the axle 66. Rotation of the gear 102 is transmitted to the shaft 62 by means of a friction clutch arrangement including friction discs 104 and operable by anticlockwise rotation of a yoke member 118 pivoted at 120 and a pawl 114 and ratchet 112 assembly. Rocking of the member 118 in the anti-clockwise direction is effected by a cam member 128 which acts against a roller 132 on the member 118. A cam holder 130 carrying the cam 128 is slidable vertically and is raised by operation of a solenoid 148, the armature 150 of which is connected to the cam holder via a pivoted link 152 and a spring 158. Upward movement of the holder 130 is limited by a stop bolt 142. Downward movement of the holder 130 is effected by a leaf spring 146 supported on the frame plate 30. The solenoid 148 is energized at the appropriate times by closure of a switch 168 operated by a cam 172 in the packaging machine 12. For effecting the heat transfer of the label the die wheel 60 has an enlarged segment 180 heated by elements 182, current for which is obtained through slip rings 188 and 190 rotating with the shaft 62 and co-operating with fixed tracks 192, 194 connected to terminals 196 and 198. The movement of the cam holder 130 may be utilized to operate a latch mechanism (not shown) to ensure correct positioning of the die wheel at the commencement of each label transferring operation. If the back roll 16 is of resilient material to ensure a substantial area of contact between the roll and die wheel the web 18 tends to be overdrawn at each cycle. Means are therefore provided for pulling back the web 18 to its correct position so that the next successive label will properly register with the segment 180 of the die wheel. Such means include upper and lower plates 202, 204 between which the web 18 normally travels. The plates are supported in a frame 206 having a lateral support 208 and spaced apart extensions 210, 212 (Fig. 4) disposed between the side frame plates 26, 28 and carrying rollers 214, 216 which run in tracks 218, 220 formed on the plates 26, 28. The frame 206 is reciprocated in the direction of travel of the web 18 by a cam 116, rotating with the shaft 62, which co-operates with a roller 230 on the upper end of a pivoted lever 226, the other end of which is connected to a lever 232 also connected to the frame 206. The plate 202 is suspended from the armature of a solenoid 224, which when energized urges the plate 202 downwardly to clamp the web 18. The circuit for energizing the solenoid 224 includes a microswitch 240 in series with co-operating contacts 242, 244 (Fig. 7) embedded in the plates 202 and 204 respectively. The contacts 242, 244 allow energization of the solenoid 224 only when they are in register with apertures 250 in the web 18. The micro-switch 240 is normally closed and is opened by a cam 252 on the shaft 62. The cam 252 is so shaped that upon engagement of the friction clutch between gear 102 and ratchet wheel 112 the switch 240 is opened to de-energize the solenoid 224, but is closed after the segment 180 of the wheel 60 has moved out of contact with the web 18 so that when the contacts 242 and 244 are aligned with an opening 250 during return movement of the frame 206 the circuit for energizing solenoid 224 can be completed to cause pull back of the web 18. Alternatively the solenoid 224 may be operated by arranging a photo-electric cell for energization by a light beam passing through the opening 250. An alternative pull-back arrangement is shown in Fig. 10 and includes a release wheel 205 having web engaging pins 213 spaced circumferentially apart a distance equal to the desired linear travel of the web 18a. The web 18a is guided around the wheel 205 and under a spring-biased pull-back plate 233 before passing between the roll 16 and die-wheel 60a. A cam 217 on the shaft 62a (Fig. 11) of the die wheel 60 serves to oscillate a lever 219 which frees a ratchet wheel 223 on the shaft 209 of the wheel 205 thus allowing the wheel to rotate an amount equal to the desired length of web to be drawn. Any overfeed causes the plate 233 to pivot about its axis. Since the plate is spring biased when the segment 180a releases the web 18a the plate 233 returns to its original position and at the same time draws back the web.