Patent GB-1099883-A (GB)
Title: Method and apparatus for forming blanks
IPC: B21D51/44
Filed: 1966-07-19
Abstract: 1,099,883. Metal strip feeds; stamping. NATIONAL DAIRY PRODUCTS CORPORATION. July 19, 1966 [Aug. 9, 1965], No. 32385/66. Heading B3Q and B3W. A method of performing two operations on strip stock comprising providing a work device having a stock entry end and first and second work stations, feeding the leading end of planar stock to the first work station and performing the first operation, advancing the stock to the second station by pushing the trailing end and performing the second operation, providing an aperture in the stock at either the first or second station while performing the first or second operation and advancing the stock by means of a finger inserted in the aperture which applies a pulling force to said strip after the trailing end of the strip has been advanced to the first station. The die-set 13 includes a lower die shoe 17, a punch holder 15 and guide columns 51. The strip feeding means comprises a carriage 21 reciprocated by the press in which the die set is fitted, or by independent means. The carriage consists of side members 65, 57 which form a guide channel for the strip stock and a bottom plate 59 in which are mounted upwardly biased pusher members 63 which are spaced apart by a distance equal to the length of the desired feed step. Attached to the forward end of the feed carriage 21 are parallel members 31 and 33 which slide in the die shoe 17. Stop faces 79 and 81 limit the forward movement of the slides. At the forward ends of the members are L-shaped arms 39, 41, pivoted on pins 89 and biased by a compression spring under the rearward end of each arm, so that feed fingers 43, 45 on the arms move towards the upper surface of the strip. The die set has three stations and forms a container lid 103, Fig. 5, which has a lifting tab 107 and a pull tab 105 for detaching a tear off strip 125 defined by a score line 123. At the first station the score line, the lifting tab and the pull tab are embossed. At the second station two holes 27 and 29 are punched, one of which, 27, blanks out the pull tab. At the third station the lid is blanked and formed and the lifting tab is blanked. The purpose of the feed fingers 43 and 45 is to take over the feed of the strip 19 when the trailing end has advanced beyond the most forward of the pusher members 63. The strip 19 is delivered on to the feed carriage 21 from a magazine when the carriage is in its rearward position. In this position the trailing end of the strip abuts the most rearward of the pusher members 63, and is pushed forward by successive reciprocations of the carriage until the trailing end of the strip is at the first station of the die-set. The feed of the strip is then continued by the feed fingers 43 and 45 which enter the holes 27 and 29 which are punched in the strip at the second station. The feed fingers have a sloping face at the rear so that they ride up out of the holes 27 and 29 on rearward motion of the carriage. The blanking and forming station of the die set includes an annular blanking punch 155, a cylindrical forming die 165 and a co-operating punch 163, and a spring-biased draw ring 157. A spring- biased stripper 149 is mounted on the punch holder 15 and an annular shedder 169 surrounding the forming punch 163 is operated by a knock-out pin 171. Spring-loaded pins 181, 183 lift the stock from the die surface as the punch holder rises.