Sheet take off device for printing or duplicating machines

Claim 1

In a printing or duplicating machine of the type including a container means for supporting and storing a stack of sheets prior to their being fed into said machine, said container having an aperture therein, and a rotatably mounted suction operated take-off roller means operable to sequentially grasp and remove the lowermost of said sheets through said aperture in said container and feed them to said machine, the improvement comprising: a plurality of fingers mounted adjacent said aperture; and means for moving said fingers back and forth between a first position wherein an end of said lowermost sheet is in the path of the periphery of said roller means and can be graspeD and removed by said roller means, and a second position wherein said fingers push said stack of sheets away from said path of the periphery of said roller means and said lowermost sheet cannot be grasped and removed by said roller means; said means for moving comprising a pivot shaft, said fingers being fixedly mounted on said pivot shaft; a rocking lever fixedly connected at a first end thereof to said pivot shaft; a draw rod connected at a first end thereof to a second end of said rocking lever; a pivotally mounted cranked lever connected at a first end thereof to a second end of said draw rod, said cranked lever having at a second end thereof a cam follower; a rotatable cam having a cam surface thereon; and means to urge said cranked lever toward a position with said cam follower in contact with said cam surface; whereby as said rotatable cam is rotated, said crank lever is pivoted as a function of the contour of said cam surface, said pivot shaft is accordingly pivoted by said draw rod and said rocking lever, and said fingers are moved between said first and second positions thereof by said pivot shaft.