GB771944A - Sheet feeding apparatus - Google Patents

Abstract

771,944. Feeding sheets. DEXTER FOLDER CO. May 20, 1955 [Aug. 27, 1954]. No. 14562/55. Class 100(1) In a sheet feeding apparatus, means for raising the pile 21 of sheets to feeding position includes a lever 71 pivoted at 72, a feeler element 52 carried by the lever and engaged with the top of the pile, a rod 84 pivoted at 83 to the lever and carrying a roller 88 adapted to engage a cam surface on a pivoted cam bar 90 when the pile height is lower than a predetermined amount, and means responsive to pivotal movement of the cam bar 90 for actuating pile raising mechanism. As described, the feeler element 52 is the usual foot clamp which rests on the pile while the top sheet is being separated by suction separators, and it may also comprise a pipe for blowing compressed air beneath the top sheet. The lever 71 is oscillated by a cam 66, and the feeler 52 is clamped to a cam link 72 pivoted to the lever at 75. A roller on a fixed pin 77 engages in a closed cam slot in the link 72, whereby the feeler 52 is rocked outwardly and forwardly as it is raised and lowered. When the pile height is lowered due to the removal of sheets, the roller 88 on the rod 84 engages a cam face 91 on the bar 90, and swings the bar about its pivot 93 to engage a plunger 105 which closes a microswitch 116 to cause a solenoid to be energized. When this occurs, the solenoid rocks a latch to release a frame carrying a pawl which can then be actuated by a cam to operate through a ratchet-wheel and gearing to raise the pile table. The cam bar 90 is pivoted to a bellcrank lever 94, 96 which can be adjusted, whilst the apparatus is operating, by a screw and nut means 101, 103, whereby the height of the pile may be varied to suit different sheets; where the sheets are thick, adjustment is made so that the cam surface 91 is engaged continuously by the roller 88 and the pile raising mechanism will then operate continuously. The plunger 105 and switch 116 are carried on a bracket 107 pivoted to the frame at 108, and a cover plate 109 secured to the bracket normally rests on a frame side plate. The bracket can, however, be swung to the dotted line position, against the action of a spring 111, where the switch 116 cannot be engaged by the cam bar 90, by the transverse manual movement of a cam 128 beneath a roller 130 carried by the bracket. This allows the pile table to be lowered to receive a new pile, but it can be used to discontinue, temporarily, the control mechanism whilst the sheet separating means is still operating. The mechanism may control the advance of a pile in a continuous feed mechanism, and hydraulic raising means may replace the pawl and ratchet means. Further, the mechanism may be used to control the 'downward movement of a delivery pile as sheets are delivered thereto. Specificatian 593,247 is referred to.