Patent GB-728672-A (GB)
Title: Method and apparatus for controlling the height of stacks or piles of paper, particularly in printing machines
Inventor: BLAETTNER KARL
IPC: B65H1/18
Filed: 1952-07-22
Abstract: 728,672. Delivery apparatus; feeding sheets. FABER & SCHLEICHER AKT.-GES. July 22, 1952, No. 18486/52. Class 100 (1). In apparatus for controlling the height of a pile of sheets to be fed to, or which have been delivered from, a machine working on sheets a feeler 12 (Fig. 2) is operated to test the height of the pile only after two or more sheets have been fed or delivered. As shown the height of a delivery table is controlled through chains (Fig. 7, not shown) by rotation of a shaft 2 (Fig. 1) on which is keyed a ratchet wheel 1. Loosely mounted on the shaft 2 is a lever 3 carrying on one end a pawl 5 and on the other end a rod by which the lever 3 is continuously oscillated. A lever 7 pivoted at 9 and co-operating with a roller 6 on the pawl 5 is normally effective to hold the pawl out of engagement with the ratchet wheel. The feeler 12 is oscillated once after six sheets have been delivered by means of a cam and follower arrangement 11. If the pile is too high a contact 14 is made which energizes an electromagnet 15 which then closes its contacts 16, 17 to complete a holding circuit over contacts 16 and to energize a further electromagnet 18 over contacts 17. Energization of the electromagnet 18 rocks the lever 9 so that the pawl 5 is free to engage the ratchet wheel 1 and cause lowering of the pile of sheets 13. The circuit is broken by a switch 20 operated by a cam 19 on the shaft 2. A manual circuit-breaking switch 21 is also provided. In a second embodiment (Figs. 3 and 4) a shaft 23 serves to actuate the pile-lowering device and is coaxial with a continuously driven shaft 22. The shaft 22 carries a drum 32 contained within clamping blocks 27, 28 bolted to a disc 24 carried on the shaft 23. The blocks 27, 28 are pivoted together at 26 and urged to frictionally engage the drum 32 by springs 30, 31. A control cam 29 is provided which, with a bolt 33 extending therefrom to engage the armature 34 of an electromagnet 36, serves to maintain the blocks slightly away from the drum 32. When the electromagnet 36 is energized on the pile becoming too high the armature 34 is withdrawn, the clamps grip the drum 32 and the shaft 23 is rotated with the shaft 22. In a further embodiment (Fig. 5) a shaft 38 on which is keyed a ratchet wheel 39 operates the pilelowering mechanism. The ratchet wheel 39 is normally operated by a pawl 41 which is continuously reciprocated. The operative stroke of the pawl is determined by a shield 43 manually pre-set by a handle 45. The shield is provided with ratchet teeth and is rotatably mounted on the shaft 38. Rotation of the shield is effected to increase or decrease the operative stroke of the pawl 41 by means of further pawls operated by electromagnets 53, 60. The electromagnets 53, 60 are selectively energized according as the height of the pile is above or below the required position. In this embodiment the feeler device is provided with a second pair of contacts adapted to close if the level of the pile becomes too low.