Patent GB-226875-A (GB)
Title: Improvements in automatic power presses for blanking and forming hollowware of sheetmetal
IPC: B21D22/06
Filed: 1923-09-28
Abstract: 226,875. Berry, G. W. Sept. 28, 1923. Metal-sheet feeds; cupping. -In an automatic powerpress for stamping hollowware from sheet metal in uniform, staggered or other formation in which the sheet is carried by grippers on a gravity fed cross-slide and positively operated main slide this is fed intermittently by pawls thereon engaging oppositely arranged reciprocating ratchet - bars 39, 40, one pawl acting at a time. The sheet is held by two clamps 82 adjustably mounted on the cross slide 74 and simultaneously operated by cams 90, Fig. 3, link 93, and lever 94. The slide 74 tends to move down an inclined guideway 70, mounted on the main slide 16, but is held by a projection 103 adapted to engage teeth 80 arranged alternately on two bars 78, 79 fixed to the guideway 70, which also carries adjustable plates 75 for supporting the sheet. The slide 16, Fig. 1, is adapted to be moved intermittently along a horizontal guideway 16<a>, Figs. 1 and 2, by one of the two pawls 43, pivoted on the slide, and the corresponding ratchet-bar, these two bars 39, 40 being reciprocated in opposite directions by an adjustable-throw crank 19, linkwork 22, 24, 29, 30, 31, and gears 26, 27. At the end of the traverse, in either direction, the pawls are reversed by a lever 44 which is moved by contact with adjustable stops 45, 45<a>. This lever also acts, through an adjustable lost motion device 96, 97, a rail 98 pivoted at 98<a>, and a fork 100, Fig. 3, to move the projection 103 from one of the bars 78, 79 to the other thus allowing the slide 74 to fall through a distance equal to that between the rows of stampings. Excessive movement of the slide 16 is prevented by a spring pressed brake 63, Fig. 1, and an index finger 51, Fig. 2, which, after each feed movement, are brought successively into engagement with a notched bar 48, carried by the slide, by means of linkwork 50, 53, 54, 55 and a cam 57. The link 50 has a projection 68, Fig. 1. which presses back the brake when the finger 51 is withdrawn by the spring 58. When the last blank has been stamped a roller 104 engages a catch 105<a> which, acting through linkwork shown, stops the press. preferably by a clutch as described in Specification 214,334, [Class 80 (ii), Gearing, Variablespeed &c.]. The crank 19 and cam 57 are rotated by bevel gearing from the main crankshaft 4. The sheet is stripped from the upper tool 2 by a spring-pressed ring 113 and the blank, ejected from the upper tool, falls into a tray 130 which is advanced to receive it by a lever 131 connected, through a lost motion device 132, to the ram. The pressure rings of the lower tool are supported by a resilient buffer resting on a support 124 which is moved, as described in Specification 219,069, by a cam 121, pinion 120, rack slide 115, eccentric 117, and bevel gearing. The first Provisional Specification also refers to Specification 192,253 and describes an arrangement in which the pawls 43 are pivoted on a separate slide carrying a finger which is moved into engagement with the bar 48, when the index finger is withdrawn, so that it can feed the main slide, but is withdrawn when the index finger is advanced.