Pickoff mechanism for mail feeder

1. A pickoff system for removal of mail pieces one at a time from the end of a stack of mail pieces supported edgewise in face to face contact with one another, comprising:

a pickoff belt mechanism positioned to frictionally engage an outer surface of a first mail piece at the end of the stack and transport it in a pickoff direction transversely to a thickness direction of the stack towards a leading end of the belt mechanism and away from a trailing end of the belt mechanism, which mechanism includes one or more belts mounted on a drive roller at the leading end driven by a drive motor and a follower roller at ((a)) the trailing end;

a pivot mechanism by which the trailing end can swing towards and away from the stack;

a drive connected to the pivot mechanism to move the trailing end towards and away from the stack; and

a controller connected to the drive to cause the drive to swing the trailing end towards the stack and swing the trailing end away from the stack in a manner effective to improve operating speed of the pickoff system, further comprising means for measuring pressure exerted by the stack against the pickoff belt mechanism, and the controller is connected to the drive to cause the drive to swing the trailing end towards the stack in response to a decrease in stack pressure, and swing the trailing end away from the stack in response to an increase in stack pressure.

2. The apparatus of claim 1 , wherein the measuring means measures load on the drive.

3. A pickoff system for removal of mail pieces one at a time from the end of a stack, comprising:

a pickoff belt mechanism positioned to frictionally engage an outer surface of a first mail piece at the end of the stack and transport it transversely to a thickness direction of the stack towards a leading end of the belt mechanism and away from a trailing end of the belt mechanism, which mechanism includes one or more belts mounted on a drive roller at one end driven by a drive motor and a follower roller at a trailing end;

a pivot mechanism by which the trailing end can swing towards and away from the stack;

a drive connected to the pivot mechanism to move the trailing end towards and away from the stack; and

a controller connected to the drive to cause the drive to swing the trailing end towards the stack and swing the trailing end away from the stack in a manner effective to improve operating speed of the pickoff system, wherein the drive is a linear drive including an extendible, retractable actuator that is pivotally connected to the trailing end of the pickoff belt mechanism, and the pivot mechanism includes a bar pivotally mounted at one end on an axis of rotation of the drive roller and pivotally mounted at its other end to the trailing end of the pickoff belt mechanism, whereby pivoting of the bar about the axis of rotation of the drive roller occurs when the trailing end swings towards and away from the stack.

4. The apparatus of claim 3 , wherein the bar is disposed beneath the pickoff belt mechanism and extends in parallel to a pickoff plane defined by the belts of the pickoff belt mechanism which contact mail pieces.

5. The apparatus of claim 4 , wherein the bar and the actuator of the linear drive are each pivotally mounted to an axis of the follower roller.

6. A method for removal of mail pieces one at a time from the end of a stack supported edgewise on a base belt conveyor, comprising:

advancing the base belt conveyor to bring an endmost mail piece into contact with the a pickoff belt mechanism;

frictionally engaging the outer surface of the mail piece at the end of the stack with the pickoff belt mechanism, which includes one or more belts mounted on a drive roller at one end driven by a drive motor and a follower roller at a trailing end, thereby transporting the mail piece transversely to a thickness direction of the stack;

cyclically swinging the trailing end towards the stack in a manner effective to improve operation of the pickoff belt mechanism by engaging a second mail piece at the end of the stack sooner than by operation of the base belt conveyor alone following removal of the first mail piece, and then swinging the trailing end of the stack away from the stack, further comprising running the base belt conveyor at a constant speed as the cyclical swinging of the trailing end occurs.