Patent GB-923525-A (GB)
Title: Improvements in or relating to systems for controlling the splicing of paper or the like webs
Inventor: RALPH FREDERICK WALLACE
IPC: B65H19/18
Filed: 1960-07-29
Abstract: 923,525. Feeding webs. WITTON-JAMES Ltd. July 27, 1961 [July 29, 1960], No. 26501/60. Class 100 (1). In web splicing apparatus including dabbing brushes 13 and knives 15 carried by a frame 14, the splicing control system includes a magnetisable surface (such as a disc 20 or an endless tape) mounted for movement at a speed directly related to the linear speed of the running web 5, together with a recording head 19 and one or two pick-up heads 21, 22. The disc 20 may be used in a number of operations for the control of splicing the web running from the expiring reel 2, to a replacement reel 3 prepared with an adhesive in a known manner. Matching peripheral speed of replacement reel with running web.-A pair of reference elements 17, 18, e.g. metallized tabs, mounted on the peripheral surface of the replacement reel 3 are equally spaced circumferentially to the circumferential spacing of the two pick-up heads 21, 22 of the disc 20. The passage of the reference elements 17, 18 past a detecting means 16 is electrically recorded on the disc 20 by the recording head 19. Assuming that the linear velocity of the recording surface of the disc under the recording and pick-up heads is equal to the linear speed of the web 5, when the two separate recordings of the reference elements 17 18 passing the detecting means 16 are simultaneously picked up by the pick-up heads 21, 22, the linear speed of the web 5 is equal to the peripheral speed of the replacement reel 3. Any difference in the respective speeds would produce an error signal from the pick-up heads, for controlling the angular velocity of the replacement reel 3. An alternative method of using the recording disc 20 is to have only one pick-up head 21 spaced from the recording head 19, so that when the respective speeds are equal, the recording of the first reference element 17 passes under the pick-up head 21 as the second reference element 18 is passing under the detecting means 16. The detecting means 16 can be magnetic, photo-electric, &c. to record a suitable form of reference element on the replacement reel. The reference elements 17, 18 may be metallic members for engaging a contact member of the detecting means or alternatively radio-active elements or elements which form capacitive couplings with the detecting means. Operation of the dabbing brushes and cutting knives. In a splicing operation it is advantageous when the dabbing brushes are operated, to control the orientation of the replacement reel. An arrangement as described in Specifications 588,901 and 888,570 may be used in which a reference element is mounted on the surface of the replacement reel in a predetermined relationship with the prepared adhesive. One of the reference elements 17 or 18 can be used for this purpose. The dabbing brushes may only operate when the linear speed of the running web and the peripheral speed of the replacement reel are equal. This may be obtained by using the recording disc 20 in another manner than that above. The replacement reel can be accelerated continuously from rest, and the pick-up head or heads used to provide a signal to operate the dabbing brushes 13 and knives 15 when the respective speeds are equal. Expiring reel diameter control.-A splicing operation is initiated when the diameter of the expiring reel 2 has reached a predetermined value. The spider 1 has to be rotated into the position shown in the Figure. The system for indicating the diameter and initiating the splicing comprises a disc such as 20, and recording and pick-up heads 19, 21, 22 as before. Reference elements 25, 26 are provided on the spindle of the reel and take the form of core pieces which effect the flux linkage in coils 27 constituting the fixed detecting means, which provides a signal to the recording head 19. The diameter of the expiring reel 2 decreases as the angular velocity increases. The spacing of the reference elements 25, 26 is chosen such that when their respective recordings are picked up simultaneously by the pick-up heads 22, 21 from the disc 20, the diameter of the reel has reached its predetermined value. As in the arrangement for matching the speeds of the running web and the replacement reel, a single pick-up head may also be used to give the same result.