Patent GB-433399-A (GB)
Title: Improvements in and relating to web-feeding mechanism for wrapping machines
IPC: B65B19/26
Filed: 1934-06-19
Abstract: 433,399. Feeding webs. INTERNATIONAL CIGAR MACHINERY CO., 5520, 2nd Avenue, Brooklyn, New York, U.S.A. June 19, 1934, No. 18100. Convention date, Oct. 27, 1933. [Class 100 (i)] Web-feeding mechanism for wrapping-machines comprises an auxiliary feeding mechanism, the extent of feeding movement of which is determined by an electrical control device coacting with markings or the like on the web, and which presents the leading end of the web to a main feeding mechanism which imparts a constant feeding movement to the web. The web W, Fig. 1, is fed by the continuously rotating rollers 79, 80 to the intermittent feed device and forms a loop in which rests a roller 82, so that when this reaches the bottom of its travel the tension of the web, and consequently the friction on the feedrollers, is relaxed, until sufficient web is withdrawn by the intermittent feed device to raise the roller 82. The main feed device comprises gripper fingers 50, 51 mounted on a slide 34 reciprocated by a rack and gear 33 which is driven from a gear segment 30, oscillated through gearing from a second segment 22. The latter is caused to oscillate by a cam 19 mounted on the driven shaft 18, and is connected by a rod 35 to a pivoted cam lever 36 bearing against a roller 37 carried by a clutch member 38, coacting with a second clutch member 39, Fig. 4, to which is attached a slide 42 on which the auxiliary gripper fingers 43, 44 are mounted. A spring 38a normally maintains the roller 37 against the cam 36 and a pin 38b on clutch member 38 against one end of a slot 39a in clutch member 39. The latter is normally pressed into engagement with the clutch member 38 and disengaged by energizing an electromagnet 45. In operation, the lever 22 moves from the full to the dotted line position and the main grippers 50, 51 are thereby moved to the left, the cam lever 36 is rocked to the right, thereby moving the slide 42, through the clutch 38, 39, to the right, so that the auxiliary grippers 43, 44 feed the web until an index mark provided thereon, in definite relation to the printed matter on any wrapper section, comes opposite a slot 56 in a photo-electric cell unit 5. This cuts off the light source from the cell and gives rise to an impulse in the circuit of an electric relay which causes contacts in the circuit of the magnet 45, to close, thus energizing it 'and disengaging thereby the clutch 38, 39 to stop the feed of the auxiliary grippers. As the clutch member 39 is attracted by the magnet 45, a push rod carried thereby closes spring contacts to complete an independent circuit through the magnet, which includes also a cam-controlled contact 63 serving at the end of the stroke of the lever 22 to open the circuit of the magnet. At this point, the grippers 50, 51 grip the leading edge of the web, which has been positioned by the auxiliary grippers with the index mark at a definite point relatively to the cutters 54, 55, and the fingers 50, 51 are moved to the right to feed the web by a definite amount, when a second pair of grippers engage the free end and, after it has been severed by the knives, feed the section forward to the wrapping point. The cam lever 36 meanwhile returns to its undisplaced position, the clutch part 39 is released by de-energizing the magnet and is also returned by the pin 38<a> and slot 39a, thus returning the slide 42 to the left for the next forward stroke of the lever 22. The photo-electric cell unit is slidably mounted for adjustment in two directions for dealing with wrappers of varying lengths. Specification 419,060, [Group XVII], is referred to.