Polaroid Corporation

Theodore J LaBelle

Kenneth A McAuley

Duncan C Sorli

Walter P Haimberger

June C Fichter

Alan M Binder

George P Ward, Jr

A sheet feeding method and apparatus particularly suited to handling plastic sheets having a tendency to adhere to each other under electrostatic action, in which the uppermost sheet of a stack is fed by first lifting the rear edge of the sheet into a generally arcuate configuration and translating a lifting member forwardly under the lifted rear edge to progressively separate the uppermost sheet from the rest of the stack. The lifting members preferably in the form of an idler roller which translates to a position in cooperation with a drive roller so that the sheet becomes sandwiched between the tow rollers for final feeding from the stack. The mechanism features a pick assembly particularly suited for engaging and lifting the rear edge of each sheet into a predictable arcuate configuration.

Sheet feeding method and apparatus

A sheet clamping system for high speed rotatable drums is provided in which light-weight clamping bars, formed of relatively thin metal sheet stock, are configured and/or oriented for maximum resistance to deflection radially of the axis of drum rotation as well as positively secured in a sheet medium clamping position at axially spaced intervals along the length of the drum. The system further includes centrifugally actuated, axially extending rods positioned to underlie the operative portion of each clamping bar in a manner such that leading and trailing edges of a retained sheet are sandwiched between the rods and the clamping bars under a clamping force generally proportional to the square of drum rotational speeds.

Dynamically stable sheet clamping system for high speed sheet handling

A counterbalancing and sheet clamp retention system for high speed sheet handling drums of the type in which leading and trailing edge clamping bars extend along the length of the drum periphery and are capable of movement between retracted and sheet clamping positions for automatic loading and unloading successive sheets to and from the drum. The clamping bars, supported at opposite ends for movement between their respective retracted and clamping positions, are engaged centrally along their length by a retaining device which moves to a clamping bar engaging position under centrifugal force as the rotational velocity of the drum reaches a predetermined value. The retaining device is a self-contained unit insertable through a radial opening in the drum and contains a pair of bell crank retainers each having a clamping bar engaging claw on one arm and a weight on the other arm so that centrifugal force operates to pivot the bell crank and bring the claws thereon into engagement with the closed sheet clamping bars. The drum is further counterbalanced by a fixed weight opposite from the movable bell crank weights. Further, the ends of the clamping bar are moved against the drum periphery to their sheet clamping positions by centrifugal force acting on counterbalancing weight carried by radially movable brackets from which the ends of the respective clamping bars are supported.

Sheet clamp counterbalancing system for high speed sheet handling drums

A cassette for releasably holding a film unit and locating it at an exposure position therein. The cassette includes base and cover sections locatable in a closed position wherein a pressure plate assembly on the cover section is movable toward and away from the base section between a raised film release position and a lowered pressure applying position wherein the film is pressed between opposed bearing surfaces, one of which may be formed by an intensifying screen for x-ray applications, within the cassette to locate the film unit at the exposure position. A simply-constructed, low-cost pressure plate assembly latching system is provided including a pair of latch members having latch tabs thereon which are captured in corresponding detents on the pressure plate assembly to releasably hold the latch members in a cocked unlatching position. In response to movement of the pressure plate assembly to the lowered position, the tabs are released from the detents and the latch members move forwardly automatically to the latching position wherein the tabs engagingly overlie the exterior surface of the pressure plate assembly to hold it in the lowered position.

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Dorchester, MA, United States of America

Theodore J LaBelle