Apparatus for applying, varying and removing a normal force in a shingler wheel type document feeder

A normal force applicator and removal device for a document stack comprising:

• a normal force applicator and removal bar having a flat front undersurface and a convex arcuate back undersurface, in reference to the direction of document insertion from back to front into said document stack, said normal force applicator and removal bar being disposed above the top of said document stack parallel thereto for transferring to and removing a normal force from the top of said document stack;
• an isolation pad adhesively attached along said flat front undersurface of said normal force applicator and removal bar for isolating and dampening therefrom mechanical vibrations from the rotation of a shingler wheel;
• a normal force transfer pad adhesively attached contiguously to said isolation pad for providing a firm surface for transferring said normal force from said normal force applicator and removal bar, while still providing some isolation and dampening of said mechanical vibrations from the rotation of said shingler wheel;
• and
• a filler pad for filling the void created on said arcuate back undersurface of said normal force applicator and removal bar by the thickness of said isolation pad and said normal force transfer pad on said front flat undersurface thereof.

An apparatus for applying a normal force to the top of and through a document stack disposed in a document tray, and through the geometric center of a shingler wheel disposed under said document tray and against said document stack such that said shingler wheel, upon rotation, generates a shingled stack of documents at a substantially constant predetermined rate, and for removing said normal force after said substantially constant predetermined rate is reached, said apparatus comprising:

• a normal force applicator and removal device for applying and removing said normal force from the top of said document stack, said normal force applicator and removal device being disposed above said document stack and parallel thereto;
• a counterbalance means for cooperating with said normal force applicator and removal device such that the weight thereof is balanced to substantially zero when said normal force is not being applied, such that said normal force applicator and removal device is maintained parallel to the top of said document stack regardless of the thickness thereof as said document stack is depleted and such that said normal force applicator and removal device follows and remains contiguous to the top of said document stack as it is depleted;
• a normal force executing means for cooperating with said counterbalance means such that said normal force is applied or removed from the top of said document stack in order to generate or maintain said shingled stack of documents at said substantially constant predetermined rate and such that said normal force is decreased as said document stack is depleted;
• and
• a normal force control means for cooperating with said normal force executing means to apply or remove said normal force, to position said normal force executing means to decrease said normal force as said document stack is depleted, and to actuate or deactuate, intermittently, said normal force executing means in order to generate or maintain said shingled stack of documents at said substantially constant predetermined rate.