Transferring products from one conveyor to the next can often times be a bit tricky, especially if the product is small in size or is tall and has a tendency to tip over. Besides having to “bridge the gap” between conveyors, there is also a matter of chordal action to consider.
Chordal action is the result of a chain transitioning from a flat state to being wrapped around a sprocket. It results in a pulsing motion of the chain (in the direction of flow) as well as a localized rising and lowering of the chain at the sprocket.
An additional issue which involves chordal action and flat chain links is that there will always be a gap between the transfer and the chain allowing product to become snagged, tip over, or fall through the gap.
Span Tech recognized this problem while talking to an industry leader in the manufacturing of tortilla shells. This company was having issues with transferring stacks of tortillas without losing one under the transfer. The problem lied within the chordal action and the distance between the transfer and the chain being just a little bit too much. To eliminate the problem, Span Tech created a new type of chain called Pillow Top. This new chain has a curved top which forms a perfect cylindrical shape as it travels around the sprocket which essentially reduces the gap between the chain and transfer to an extremely small amount (practically touching). This design feature allowed the tortillas to transfer successfully and eliminated the issue with the bottom tortilla getting pulled under the transfer.
Since the initial success of transferring tortillas, Pillow Top has proven to be successful at transferring all kinds of difficult products such as freshly-baked cookies, croissants, and several other rigid and flexible items. One unintended feature of Pillow Top chain is that the added material in the upper portion of its design makes the entire chain stronger so that it can be used in more demanding applications.