Patent ID: 7322078
Filing Date: 2008-01-29
Classification: B29C

Abstract:
1. A drive device for a system for the transverse drawing of films of synthetic material for holding, transporting and drawing the film, successive grippers supported and guided by rails, and driven forward by endless chains connecting the grippers together, which comprises, for driving each endless chain connecting the grippers, at least two drive sprockets of a large diameter, namely a drive sprocket situated at a front end of an outbound strand of the chain and another drive sprocket situated at a rear end of a return strand of the chain, there being associated with each sprocket a motorized means for rotationally driving this sprocket and the motorized drive means associated with the two respective sprockets being synchronized with one another; wherein each drive sprocket of large diameter consists of an outer annulus with a tooth set tailored to suit the chain that is to be driven; and a fixed horizontal support part, the annulus and said support part being joined together by a collection of balls or of rollers providing rotational guidance of the outer annulus, while the support part is fixed horizontally to a support structure.