Patent GB-952415-A (GB)
Title: A pile handling mechanism particularly adapted for sheet feeding apparatus
IPC: B65H1/30
Filed: 1962-01-09
Abstract: 952,415. Feeding sheets. HARRIS-INTERTYPE CORPORATION. Jan. 9,1962 [Jan. 23, 1961], No. 779/62. Heading B6B. In sheet-feeding apparatus wherein the pileraising mechanism has a main and an auxiliary pile-raising means, the latter can raise the depleted pile in increments or continuously and is driven by a rotary air-motor through reduction gearing, the speed of the motor varying with the load of the depleted pile. As shown, the main pile table 10 is suspended by cables 20 which can be raised or lowered continuously by power-operated means, or by increments through a pawl and ratchet means 24 under the control of a pile-height detector 40. The detector 40, Fig. 5, includes a feeler 53 periodically reciprocated by a cam 57, and when the pile height is below a predetermined limit, a shaft 70 is rocked to swing a rod 50 to allow a bell-crank 39 to be swung by a cam 44 to cause a masking lever 33 to pivot at 36 and lower a pawl 27 into engagement with a ratchet 25. The pawl 27 is oscillated constantly about the ratchet 25 by an oscillating link 29, and when it engages and drives the ratchet, it causes the table 10 to be raised. The auxiliary pile-raising means 11 comprises two rails 80, 81, vertically guided at 82, which are supported, respectively, by chains 83, 84 and 90, 91 the ends of which, after passing over sprockets, are secured to sprockets 87, 88, and 94, 95, Fig. 2, secured to a shaft 89. One complete rotation of the shaft 89 effects the full raising or lowering of the auxiliary pile-raising means 11, and this shaft is adapted to be rotated through worm gearing 102, 103, Fig. 2, a vertical shaft (104, not shown), and a reduction unit, from a reversible, rotary air motor 110 having a low torque, high speed, and a rotor of low inertia. Opposite sides of the rotor are connected to a supply of compressed air or to atmosphere through three-way valves 116, 118 operated by solenoids in an electric circuit which is arranged to provide continuous rotation of the motor 110 in either direction on manual depression of switches, or automatic incremental rotation thereof to raise the pile under the control of the feeler device 40 associated with the main table 10. When the auxiliary pile table 11 is controlled by the feeler device 40, the.rocking of the bell-crank 39, Fig. 5, operates a switch 125, 126, and a solenoid 42 lifts the masking lever 33 so that the pawl 27 cannot engage the ratchet 25. Thus, when the feeler 53 detects a low pile, the switch 125, 126 is operated by the lever 39, the air motor 110 is driven for a period corresponding to one-third of a revolution of the vertical shaft (104) which has three spaced switches thereon, and the pile is raised by a corresponding amount each time the switch 125, 126 is operated. The electric circuit includes a holding circuit for the appropriate solenoid valve controlling the supply of air to the motor, and this is responsive to the switches operated by rotation of the vertical shaft (104). In operation, the main table and pile is raised continuously to the feeding level, and then raised incrementally under the control of the pile height detector 40 through the pawl and ratchet means 24. When the pile has been depleted to such an extent that the table 10 is sufficiently above the rails 80, 81 of the auxiliary table 11, a number of supports 161 is inserted beneath the pile to bridge the rails. The table 11 is now raised quickly by the air motor 110 until it encounters the pile, and then at a slower rate due to the weight thereof, to raise the depleted pile, so that the main table 10 can be lowered to receive a new pile, and the table 11 is then operated incrementally under the control of the pile height detector 40. When the new pile is raised by the main table 10, the supports 161 are withdrawn to deposit the depleted pile on to the top of the new pile, and the main table is then raised under the control of the detector 40, there being no interruption of sheet-separation during pile replenishment. The upper and lower positions of the table 11 are controlled by a dog 160 on the shaft 89 which operates limit switches 158, 135, respectively.