Vacuum drive assembly

Abstract

A drive assembly ( 10 ) to drive packaging film for delivery to a packaging machine. The assembly ( 10 ) includes an elongated endless flexible belt ( 11 ) with a plurality of teeth ( 16 ) that are used to drive the belt ( 11 ). The teeth ( 16 ) are arranged in rows along the longitudinal edges of the belt ( 11 ). Between the rows of teeth ( 16 ) is a row of apertures ( 23 ) that communicates with a gallery ( 20 ).

1 . A vacuum drive assembly including:
 a gallery to which reduced air pressure is to be applied, the gallery having at least one aperture;   an endless belt engaged with the gallery so as to be movable past the gallery in a predetermined direction, the belt having a longitudinally extending inner surface and a longitudinally extending outer surface between which apertures extend, the apertures being located at longitudinally spaced locations along the belt and are to be aligned with the gallery aperture so that reduced air pressure is applied to apertures of the belt aligned with the gallery aperture, a plurality of drive teeth located at spaced locations along the inner surface to be engaged by a drive sprocket that is to drive the belt in said direction, the projections being arranged in a pair of parallel rows, the rows each extending longitudinally of the belt but being transversely spaced so that the belt apertures are located between the rows; and wherein   said gallery has a pair of elongated guide projections located between the teeth and engaged with the inner surface to aid in sealingly connecting the inner surface to the gallery, with the teeth also engaging the projections so that the belt is guided thereby in passing the gallery.   
     
     
         2 . The assembly of  claim 1 , wherein said gallery aperture is a slot extending in said direction. 
     
     
         3 . The assembly of  claim 1 , wherein the drive teeth are arranged in pairs, each pair consisting of a tooth from each of the rows, with teeth of each pair being transversely aligned, with a belt aperture located therebetween. 
     
     
         4 . The assembly of  claim 2 , wherein the drive teeth are arranged in pairs, each pair consisting of a tooth from each of the rows, with teeth of each pair being transversely aligned, with a belt aperture located therebetween.