GB218151A - Improvements in or relating to devices for feeding sheets to printing-presses, folding-machines and the like - Google Patents

Abstract

218,151. Spiess, G. Aug. 27, 1923. Tripping-arrangements.-In sheet feeding devices for printing presses, folding machines, &c. in which a feeler pawl 15 on an oscillating lever 13 or 29 engages a driven ratchet wheel and so operates a system of levers to raise the feeding wheel 2 out of feeding position temporarily, and in which the pawl 15 is disengaged from its ratchet wheel by the acceleration of the oscillating lever, the acceleration is increased by a pair of link levers 22, 23 or 29, 30 approaching a straight line position. the acceleration being limited by the straight line position. In operation a sheet fed in by the feed wheel 2 moves the feeler end of the pawl 15 so that the pawl 15 engages with the rotating ratchet wheel 18. The pawl 15 is pivoted at 14 on the lever 13, Figs. 1 and 2, and wheel 18 drives the pawl 15 round until it engages a stop pin 27 on the lever 13. Lever 13 is thus rocked about its pivot 12 causing its race-surface 11 to move under a roller 10 and so raise the end of a lever 8 which is pivoted at 7. Pin 6 of lever 8 thus moves the forked end 5 of the lever 4 which raises the feeding wheel 2 out of feeding position. When the link levers 22, 23 are nearly straightened out the roller 10 mounts the horizontal race-surface 11<a> and resistance is thus suddenly interrupted whereupon lever 13 receives an acceleration from the weight of the link levers which causes the pawl 15 to overrun its ratchet wheel 18 and so free itself with the help of the spring 16. This acceleration ceases as soon as the link levers are in a straight line. The parts are now in the position shown in Fig. 2, the pawl 15 bearing against the pivot pin 12. To reset the device the cam 26 bends the links up again until link 23 abuts against a stop 36 pulling the top of lever 13 to the left so that spring 9 may pull lever 8 back and permit feed wheel 2 to be lowered into contact with the sheets by co-action of cam 20 and rollers 21. Fig. 3 shows a modification in which 29, 30 are the straightening out link levers, the feeler pawl 15 being mounted on lever 29 which is connected by the link 30 to the lever 28. Lever 29 is pivoted at 12 and has its lower end attached to a spring 31 which, while the levers are being straightened out at first retards the movement since its axis of pull lies to the right of the pivot 12, but immediately the axis of pull of the spring has moved to the left of the pivot point 12. the spring gives the levers an acceleration to disengage the pawl 15 from the ratchet wheel 18. A cam 34 on the ratchet wheel shaft acting on a roller 21 brings the levers into feeding position again. The link levers 29, 30 may have a slotted connection to permit play. Fig. 5 shows an addition to Fig. 3 of locking notches 41, 46 and 48 in arms 39, 44 actuated by springs 38, 40 which operate to hold the levers in the stretched position and in the normal starting position.