GB259073A - Tripping mechanism for platen printing presses - Google Patents

Abstract

259,073. Aclkley, A., and Plum, S. H. Dec. 24, 1925. Tripping-arrangements.-In a platen printing- press having the usual tripping-mechanism 13, Fig. 1, operated by a hand-lever 14, means are provided for throwing the lever into tripping position when a sheet is not fed, comprising a trip arm 20 oscillated from the forme 7, and adapted to move the lever 14 to tripping position by engaging with a normally-retracted latch 29 on the lever which is released when a sheet is not fed. The latch 29 is pivoted to a member 44 drawn downwardly by a spring 51 and normally kept raised by the engagement of a spindle 42 on the lever 14 with a slot 48 in the member 44. Mounted on the spindle 42 is a spring-controlled disc 37 having a pin 38 engaging the member 44, and an arm 35 engaging a bellcrank lever 80 pivoted on the feed table 18. When the lever 30 is rotated clockwise, the pin 38 on the disc 37 disengages the member 44 from the spindle 42 and the spring pulls the member downwardly with the spindle resting in a second slot 49 and the latch 29 in tripping position. The lever 30 is retained in its normal position by a spring-controlled handle 268. Fig. 6, engaging one arm thereof, and a spring 161 pulling it towards the handle. A rod 163 connects the lever 30 with a pivoted hook member 165, and when no sheet is fed the rod is pulled to the left to operate the lever 30 bv the engagement with the hook 165 of a hook 174 on a lever 76 carrying the suction-feed apparatus and oscillating between the feed table 18 and the platen. At the same time the handle 268 moves against a stop 177 and holds the lever 30 in tripped position until reset by hand. The hook 174 is carried by a spring-pressed lever 169 pivoted to the lever 76 and to a piston-rod 167 operated by a cylinder 166 connected to the suction apparatus and carried by the lever 76. When a sheet is fed a suction effect is caused in the cylinder, the rod 167 being drawn into the cylinder and the hook 174 raised out of the way of the hook 165 against the action of a spring 172. The trip arm 20 is formed with a cam surface 26 and two projections 27, 28 at its upper end, so that when the latch 29 is in tripping position the projection 27 moves the lever 14 to tripping position on the closing movement of the press and the projection 28 moves the lever 14 to imtripping position on the opening movement of the press, while the cam 26 lifts the latch 29 during the opening movement. If the handle 268 is now reset, the lever 30 and disc 37 under spring action are restored to their normal position, and when the cam 26 lifts the latch 29 the spring 41 moves the member 44 so that the spindle 42 seats in the slot 48 and the latch 29 is retained in untripped position. A cam 175 engages a pin 173 on the member 169 and disengages the hooks 165, 174 when the rod 163 has been moved sufficiently to the left. When hand-feeding is employed the member 44 is moved by hand so that the spindle seats in a third slot 50 and the latch 29 is held permanently in untripped position.