GB704697A - Improvements relating to the feeding of wrapping materials to wrapping machines and the like - Google Patents

Abstract

704,697. Feeding webs. FORGROVE MACHINERY CO., Ltd., HARRIS, R. A., PARKER, M., and CARTER, A. F. Aug. 8, 1952 [Sept. 13, 1951],No. 21537/51. Class 100 (1). [Also in Group XL(b)] In machines in which a web of printed material used for wrapping or bag forming is fed to a stage at which its arrival should be accurately registered, e.g. with an article to be wrapped; a detector, e.g. a photo-electric cell, responds to marks on the material to operate an electromagnetic clamp to arrest the feed of the web. As shown, Fig. 1, a web 10 of outer wrapper is drawn from a reel 11 over a spring loaded jockey arm 12 by means of a pair of continuously rotating feed rollers 15. A web 16 of inner wrapper is drawn from a reel 17 over a jockey 18 and the two superposed webs pass over a spring loaded wire loop 22, Fig. 2, through a gap 41 between an electromagnetic armature 25 and an anvil 23 to a pair of intermittently rotating rollers 28. Web 10 carries a series of marks spaced along the web which are detected by a light source 32 and photo-electric cell 31 receiving light reflected from the web. When a mark is detected by the photo-cell, the end of the two webs is correctly positioned for the wrapping operation and the electromagnet armature 25 is released by a relay so that a spring 39 is able to move the armature to clamp the webs between it and the anvil 24, feed rollers 28 slip on the web for the remainder of their rotation and knives 29, 30 sever the part to be used. When the clamp is operated the surplus web accumulating between it and the rollers 15 is taken up by wire loop 22 until a flat on one of rollers 15 engages the web when it is drawn backwards through the rollers by the spring loaded jockey arms. The armature is restored, to a position where the re-established field of the armature can hold it, by a pivoted lever 42 rotated by a shaft 46 and links 44, 45. This shaft also removes the lever from the armature before the clamp is again to be operated. According to the Provisional Specification, the electromagnet clamp may be switched into a circuit by a relay in response to detection of the marks on the web. Specification 262,588, [Class 100 (1)], is referred to.