Patent GB-832885-A (GB)
Title: Improvements in or relating to machines for working sheet metal
IPC: B21D21/00
Filed: 1958-04-09
Abstract: 832,885. Shearing; stamping. HAMMERLE A.G. April 9, 1958 [April 9, 1957], No. 11159/58. Class 83 (4). A sheet-metal working machine for cutting, flanging, seam-pressing or screw-thread forming having two commonly driven tool shafts, one of which is mounted in a movable mounting element so that the spacing between the tool shafts can be varied is characterized in that two drive arrangements are provided for the movement of the mounting element for use according to choice, one drive having a rotating control shaft and the other a pressure actuated piston. The machine has a housing 21 and a rocker 22 pivotable about a shaft 23 said rocker carrying an upper tool shaft 24 on which is mounted a circular cutter 25. The counter blade is carried on the end 27 of a lower tool shaft 26. Workpieces, e.g. tins, are supplied to the tools by a feed apparatus 28 having two fixed guide plates 29 and 30 and adjustable guide strips 34 and 35. A pivoted feed lever 39 supports the lowermost tin in a saddle 43 and transfers it to a position in front of the lower tool shaft whereupon a presser rod 50, actuated through spring-loaded linkage from a cam 74 on a control shaft 76, presses the tin into the lower tool. The saddle has an arcuate end-piece 49 for supporting the following tins when the lever 39 is in the feed position. The end of the presser rod carries an arm 78 (Fig. 1), which supports two rods 79 and 80 on which are secured devices (not shown) for the removal of the workpiece from the machining and retaining tool mounted on the lower shaft. The tool shafts are driven from a motor 81 which drives a main shaft 84 through a speedvarying device 83. A pinion 97 on the main shaft drives a gear-wheel 98 on the input shaft 99 of a reduction gearing. A gear-wheel 101 rotatably mounted on the reduction input shaft 99 with means so that it can be coupled thereto if desired, engages a gear 103 on a stationary shaft 105 which is in mesh with a gear 109 on the lower tool shafts 26. The gear-wheel 103 also engages a transport gear-wheel 110 mounted on a shaft 111 and drives a gear change unit 115 which enables the transmission ratio between the gear-wheel 110 and the upper tool shaft 24 to be varied. The gear change units can also be adjusted so that the tool shafts rotate in the same or opposite direction. The drive can also be effected through a differential 127 (Fig. 3), the sun-wheel 128 of which is mounted on the shaft 105. Also releasably coupled to the reduction input shaft 99 is a gear-wheel 140 which, through reduction gearing, can be connected to the drive train of the tool shafts. The spacing of the tool shafts can be varied by pivoting the rocker 22 which is effected by a rod 148 connected to a spring-loaded double lever 160 pivoted to the housing 21 at 161 and operated by a cam 165 on the control shaft 76 which also carries the cam for operating the presser rod 50. The cam operation is used for fully automatic machines and in order to move the rocker slowly or to retain it in one position a pneumatic or hydraulic drive cylinder 168 is provided, the piston-rod of which operates the rocker through toggle bars 175, 176, one of which is connected to the rod 148, the other being pivoted to the housing 21. When the rocker is to be cam actuated the toggle bar is disconnected from the actuating rod 148. The drive cylinder 168 is controlled by a valve 187. The control shaft 76 is constantly rotated in a fully automatic machine but for single operations a control mechanism actuated by a pedal 211 is provided to connect or disconnect the gear-wheel 199 with the control shafts by means of a catch lever 216 having a hook 218 which co-operates with the nose 219 of a rotary wedge 220 (Fig. 6), a braking device 227 ensures smooth engagement of the control mechanism and an uncoupling device 243 is provided which automatically effects uncoupling after each revolution of the control shaft. In a modification a change-speed gear with shiftable transmission stages is mounted in the drive train of the upper drive shaft 24 in place of the gearchange unit 115 and of the exchangeable transport gear-wheel 110 the advantage being that it is possible to set a large number of different transmission ratios and also to change over from operation with or without differential by merebly operating the shift levers. A brake is provided for bringing the tool shafts to a halt during a part of each revolution of the control shaft 76. The housing may be provided with additional feet to permit setting up the machine with the tool shafts disposed vertically. The machine may be used for cutting a four-edged sheet metal box 303 (Fig. 13), utilizing a blade 304 and a four-edged retaining tool 305.