Patent GB-797724-A (GB)
Title: Improved sheet-feeding mechanism
IPC: B65H1/18
Filed: 1956-08-13
Abstract: 797,724. Feeding sheets. ROSBACK, CO., F. P. Aug. 13, 1956 [Aug. 12, 1955], No. 24729/56. Class 100(1) Pile supports. In apparatus for separating sheets from the top of a stack of sheets which is kept at a constant level under the control of feeler means, the sheet-separator means is movable upwardly from its normal position, and when so moved a further control means disables the drive means which raises the stack. The invention is an improvement in apparatus for feeding sheets to a sheet-perforator as described in Specification 797,723. The stack 3 of sheets is supported by a platform 2 resting on brackets 4 each guided on posts on the frame by rollers and secured to a chain 5 passing over a drive sprocket 33. Each sprocket 33 is adapted to be driven through worm gearing by a cross shaft 37 having a ratchetwheel 40 secured to one end, and a crank handle 41. An assembly comprising a pawl 42 mounted in side plates 43 pivoted about the shaft 37 is constantly oscillated about the shaft by a rod 57 which is crank-driven by the electric motor 59 of the associated perforator (not shown), a bell-crank lever 50, and a pneumatic cylinder 45 attached to the plates 43. The cylinder 45 has two spaced end plungers 46, 47, the upper one 46 being projected from the cylinder, when the lower one 47 is forced into the cylinder, by the compressed column of air between the plungers. The plunger 46, on projection, tilts the pawl 42 into engagement with the ratchet-wheel 40 to cause the pile 3 to be raised on the upward swing of the cylinder and pawl assembly; but if the column of air between the plungers is open to atmosphere, the plunger 46 is not projected, and the pawl 42 swings idly around the ratchetwheel 40. The air column in the cylinder- 45 is in communication with a valve embodied in a feeler unit 64 supported abovethe pile 3 on a rod 61 pivoted about a vertical post 60, as described in Specification 797,723. This valve is closed by the feeler when the top of the pile 3 falls below a predetermined level. The plunger 47 is pivotally attached to the bell-crank lever 50 at 53, but it can be attached to the other points along the lever to vary the rate of elevation of the pile: this plunger first moves into the cylinder 45, and then a stop 48 thereon lifts the cylinder bodily. If the feeler unit 64 fails to operate, or for some other reason the pile continues to rise, the top of the pile presses against the sheet-separating suction roller 8 and causes a switch 67 in the circuit of the driving motor 59 to be opened, thus stopping the sheet-feeder and perforator. Sheet-separators. The sheets are separated from the pile 3 by a rotary suction wheel 8 secured to a shaft 9 mounted for vertical movement in slots in posts 10. A limit switch 67 in the circuit of the driving motor 59 has a plunger 68 which extends downwardly into contact with the shaft 9, and when the pile is raised too high, as explained above, this switch is opened. The shaft 9 is driven by a belt and pulley arrangement from the shaft 13, this arrangement including a split-cone variable-speed pulley 12, and an idler pulley 15 which can be adjusted to tighten the belt and thus alter the speed of the shaft 9 and suction wheel 8. The shaft 13 is driven from the perforator, and carries sheet-forwarding tapes 18. Small horizontal guides 24 positioned beneath the wheel 8 assist sheet separation. Suction is applied to the wheel 8 by shoe 26 at one end, the wheel having transverse and radial passages. An air pipe 29 leads from the shoe 26 to a valve assembly of known type which can be set by a handle to provide for overlapping stream feeding from the pile.