Here is an application that involves the requirement for stable conveying of pouches for inspection, printing, labelling or edge sealing. Two belt conveyors are mounted on edge to "Grab" pouches or other products. Fitted with pliable belts with a little "Give" in the belt surface material. The position of the conveyors relative to each other can also be made adjustable for a variety of product sizes. Once the conveyors are adjusted to the proper width the product is effectively “locked” into place along the travel distance. During this time the required marking or packaging operation can be carried out. The adjustable width motion can be automatic or manual and the decision between the two options here would usually be based on the amount of times the distance is to be changed due to product line changes. These common driven opposing belt conveyors in the photos are mechanically connected from a single drive motor to achieve a common speed, but it's also possible and sometimes cheaper to use 2 motors and adjust the speed of each motor to attain a common belt speed. This is necessary because even 2 identical motors will rarely operate at the same speed exactly due to coil winding variations. Another benefit of this belt conveyor based system is that it maintains pouch spacing and provides inspection or label application access to the bottom and top of the product.
More details will be available at http://www.asconveyorsystems.co.uk/belt-conveyors.html .