Film wrapping dispenser having a fluid pressure actuated, controlled drag shaft

Abstract

A film wrapping dispenser having a fluid pressure actuated, controlled drag shaft is disclosed. It comprises a cylindrical, hollow tube wall which is formed of an extensible material which envelopes a fluid pressure-tight cavity. The tube wall rotatably engages an inner cylindrical bearing surface of a relatively rotating member. A controllable fluid pressure source is connected to the tube for selectively applying fluid pressure within the cavity to radially expand the tube wall. This enables the selective frictional engagement of the tube wall with the inner cylindrical surface of the member. The pressure source may be a bellows shaped as a handle which is integrally formed with the tube wall on one end of the cylinder. The tube and bellows may be precharged with a fluid pressure of sufficient magnitude to impart a relatively low degree of frictional engagement when the bellows is relaxed and to provide a relatively high degree of frictional engagement when the bellows is compressed. The device finds particular use as a film wrapping dispenser for improved manual control of the film tension while wrapping containers on a pallet, for example. A roll of plastic wrap webbing is rotatably mounted on the shaft and the operator, by grasping the handles on the ends of the shaft, can controllably dispense the webbing and controllably tension the webbing during the wrapping operation by selectively squeezing the bellows handle.

Dependencies are inferred from the claim text.