U.S. Pat. No. 4,155,441 to Albrecht et al. discloses a conveyor system for separating columns of articles into spaced groups, each group containing a predetermined number of articles. The columns of articles are fed onto a conveyor having an extendable noser arrangement at the output end that is positioned over the input end of a second conveyor. The noser arrangement is extended to prevent the flow of articles from the first conveyor to the second, faster conveyor, thereby providing a space on the second conveyor between successive groups or articles. During extension of the noser arrangement, no articles are transferred since the noser arrangement extends the conveyor at the same rate that the articles are carried toward the end of the conveyor. A photoelectric device counts the articles as they are transferred and actuates the noser extending mechanism. U.S. Pat. No. 4,155,441 does not disclose changes in the noser arrangement due to the detection of an unevenly spaced article. In addition, this patent does not disclose continuous correcting of unevenly spaced articles during transfer to a second conveyor belt.
Devices for shingling articles are known. For example, FIG. 1A shows a side view of a typical shingle stacking conveyor arrangement. The speed of the first belt (V1) is faster than the speed of the second belt (V2). This causes the articles on the second belt to be spaced closer together and to overlap or shingle. FIG. 1A shows an article that is ahead of where it would be if it were evenly spaced, causing it to arrive early at the second conveyor. FIG. 1B shows an article that is behind the position it would occupy if it were evenly spaced, causing it to arrive late at the second conveyor.
The effect of uneven article spacing on the first conveyor is to cause an uneven article spacing on the second conveyor, which results in an uneven shingle pattern (i.e., the articles are shingled at different angles). If the product arrives sufficiently ahead or behind of an evenly-spaced position, then the shingle pattern can be lost altogether, resulting in articles being piled on top of each other in a random manner, as shown in FIG. 1C.
Randomly spaced or randomly stacked products is not just a matter of aesthetics. Unevenly distributed product does not go through conveyor systems to wrapping systems well. Any disruption in the pattern of products only gets worse as it makes its way to wrapping. Loss of product overlap, buckled product, and product jams all occur with regularity. When the disordered product arrives at the wrappers, it is prone to jam in chutes, feed mechanisms, infeed track, and the like. As a result, serious product breakage and wrapper downtime occurs. The present invention provides an apparatus that can take a single row of unevenly spaced articles on a first conveyor and ensures that the articles are more evenly spaced or more evenly stacked on a second conveyor.