Patent ID: 7472528

Claim:
A vacuum belt assembly to drive tubular bag material, the bag material having a generally central longitudinal axis and to pass through a packaging machine, the assembly including: a first and a second drive belt arranged adjacent to each other and extending generally parallel to said axis, each belt having an endless outer face to engage the tubular bag material and a plurality of passages at longitudinally spaced locations along the belt, each passage extending through the belt from an aperture in the outer face of the belt, with each belt having a length to engage the bag material, with the apertures of the length of the first belt being arranged in a first generally flat plane, and the apertures of the length of the second belt being arranged in a second generally flat plane, wherein the lengths of said first and second belts are generally parallel and the planes are inclined by an angle greater than 0° but less than 180°, the angle being located in an angle plane extending generally normal to the lengths so that the lengths at least partly face each other to engage the tubular bag material; a third drive belt located opposite and parallel to the first and second drive belts and having an endless outer surface to engage the tubular bag material, the third belt further having a plurality of passages extending from apertures at longitudinally spaced locations along the third belt, and a length to engage the bag material; a vacuum gallery operatively associated with each length and to apply a vacuum to the length of the belts so that via the passages the apertures of the lengths have a reduced air pressure to thereby have the tubular bag material urged in contact with the lengths; a motor assembly to drive each belt so that the lengths move in unison in the same direction to drive the tubular bag material; and a guide for each belt length, each guide engaging its respective length to cause angular deflection thereof about the longitudinal axis of the belt to position the apertures in their respective plane.