GB604232A - Improvements in or relating to sheet handling mechanism for use in printing presses - Google Patents

Abstract

604,232. Printing-machines: feeding sheets. HARRIS-SEYBOLD CO. Oct. 25, 1945. No. 28156. Convention date, March 11, 1942. [Classes 100(i) and 100(ii)] A throw-off mechanism for printing- presses controlled by a feeler which trips the. impression cylinder if a sheet is not fed properly to the sheet grippers is constructed with a detector feeler 91, Fig. 8, which is mounted to swing about an axis transversely of the sheet path, and is adapted to engage the taut edge of the sheet as the sheet is engaged by the central gripper 62<1> of a number of grippers 62. The feeler 91 coacts with a detector plunger 79 and prevents it from being raised if a sheet is held taut by the grippers, but if no sheet is present the plunger 79 is raised and sets in action mechanism for tripping the impression cylinder of a printing-couple 26, 27, Fig. 1, to which the sheets are fed from a drum 50 by means of grippers 62, 62<1> mounted on carriers 34, carried by chains 24 and adapted to be firmly attached to recesses in a drum 39 as described in Specification 604,264. When a carrier 34 is received by the drum 39 the plunger 79 registers with a spring-pressed plunger 118 mounted in a central portion 101, Fig. 3, secured to brackets 103 on the inside of the drum 39. The plungers 79, 118 are normally pressed downwards by springs but are acted upon by the end 117 of a spring-pressed pawl 112 mounted on an oscillating arm 110, and as the spring 113 of pawl 112 is stronger than the springs tending to depress the plunger 79, the plunger 79 is raised if not held by the presence of a sheet between the grippers. If this occurs the pawl 112 can move counterclockwise, and the end 128 of the pawl 112 engages a notch 129 integral with a gear sector 135 which is thus rotated due to movement of the arm 110, and causes rotation of a shaft 137 mounted centrally of the drum 39 in such manner that it can move axially so as to cause its conical end 189 to project beyond a cam 192 secured to an axle 41 of the drum which is mounted in roller bearings 42. Normally the arm 110 oscillates without affecting the shaft 137. The movement of the shaft 137 is effected by a coarse screw 139 engaging a fixed nut 140, and the movement of the shaft controls the mechanism for tripping the impression cylinder 26, Fig. 10. The cylinder shaft 150 is mounted at each end in eccentric bearings 151 which are controlled by an adjustable link 153 and a lever 158 on a shaft 159. The lever 158 is provided with a pair of pins 160, 161 which are selectively engaged by shoulders 172, 173 on a reciprocating hook member 162 which is operated by an oscillating lever 163 actuated by a cam 166 secured to the axle 41. The member 162 is moved about - its pivot 164 by a lever 179 controlled in position by cam mechanism associated with the axial movement of the shaft 137, and adapted to trip the cylinder 26 when ' a sheet is not held by the gripper 62<1>. The lever 179 is controlled by a cam 192 arranged adjacent to cam 166 as shown in Fig. 3, and as shown in Fig. 12 the pin 197 which transmits motion to lever 179 from cam 192 is arranged out of the plane of the cam. The axial motion of the shaft 137 causes the lever 179 to move counterclockwise in Fig. 10 thus moving the hook member 162 into position to ‹ngage pin 161 and trip the cylinder 26. A spring 200 moves the pin 197 mounted in lever 179 axially so as to engage the high portion of cam 192 and so maintain the cylinder 26 tripped until the low part of the cam permits the return of the lever 179 to a position in which the impression is thrown on. A sloping part 196 of cam 192 then moves the pin 197 axially to its original position, and the cylinder 26 is restored to printing position and remains in action until the trip mechanism is again actuated consequent upon failure of the gripper 62<1> to hold a sheet. Specification 604,233 also is referred to.