GB782556A - Improvements in or relating to flying shears having preselected miss-cut action - Google Patents

Abstract

782,556. Shearing. HALLDEN MACHINE CO. Dec. 5, 1955, No. 34797/55. Class 83 (4). In flying shears for cutting moving stock s, Fig. 7, by means of apertured cutters 90, 92 on a longitudinally reciprocating head 86, the cutter 92 is continuously reciprocated vertically without engaging the work, by an eccentric 274 and after a predetermined number of revolutions is raised by a second eccentric 276 to a higher position at which it cuts the work. The eccentric 274 is coupled by a pin 300 (not shown) to a pinion 284, Fig. 2, in the machine drive and the eccentric 276 is actuated by a rack 308 engaging a pinion 306 on its keyed shaft 278 and operated preselectively by a double-acting fluid pressure cylinder 314. The cutter head 86 is reciprocated longitudinally by an arm 160 pivoted at 168 to the cutter slide 82 and oscillated about a link pin 182 by a second eccentric 162 on a shaft 164 of the machine drive. The drive has an infinitely variable speed-adjusting means (not shown) for varying the length of the work cut and additional oscillation is imposed on the arm 160 to move the cutter head 86 in unison with the speed of the moving work over part of its stroke, irrespective of the frequency of reciprocation. This oscillation is obtained from a third eccentric 186 and connecting rod 184 carrying the link pin 182. The eccentric 186 is rotated on its shaft 188 by rack and pinion 328, 330 operated from a crank pin 326 on a disc 190 rotating on the machine drive shaft 164. The amount of rotation of the eccentric 186 is variable by radial adjustment of the pin 326 on the disc 190 to vary the amount of superposed oscillation and reduce or increase the speed of the head 86 so that it moves in unison with the work. A substantially constant velocity is obtained over part of the stroke by making the pinion 330 eccentric. A miss-cut control is provided so that after a given length of cut per revolution has been determined from the preset drive speed of the eccentrics 162, 274 the fluid pressure cylinder 314 which actuates the eccentric 274 to bring the shears into cutting positions is actuated after a predetermined number of revolutions. A cam 380 and group 'of switches 390 send electric impulses to the counting mechanism and control the automatic return to zero after each shearing operation. The work is fed to the shears at a constant speed by opposed chains 20 running on sprockets 22a and carrying V-blocks 33 which engage the work. The blocks 33 roll over supporting rollers 40 (not shown) rotating on spindles in carriers 48. The correct clamping pressure is obtained by adjustment of the carriers 48 which are supported by adjustable eccentrics 52 engaging in slots 62 in the carriers.