Chains for power transmission or for material handling and processing systems, such as, for example, chains which function to move a plurality of trolleys or the like along a path or conveyor line in a processing plant, warehouse or the like, typically include multiple sections or links joined together by pins or bolts, such as I-pins or other connecting elements. As the chain is moved along the conveying path, the links and sections of the chain undergo bends and turns along a continuous conveying path or chain loop. As a section of chain bends, the pins may rotate within the openings in the center links and/or side links, which results in wear on both the pins and the center links and/or side links. The wear leads to an increase in the effective length of the chain or section of chain as well as a change in the pitch of the chain as gaps then may occur between the pins and links. It is generally undesirable to allow excessive wear in the chain, since this results in slack in the chain and/or a change in chain pitch and/or a change in the distance between products being processed, or may further result in noise and further wear or weakening of the chain. Typically, when the chain wear results in an increase in length of approximately 4-6 inches in a length of a section of chain that is initially a 10-foot section of chain, the chain must be replaced.
Typically, the length of a chain or section of chain is measured by detecting chain features, such as a forged pin or a forged chain link as the chain travels along the conveying path. Such known measurement devices may measure relative wear on a conveyor chain based on an initial base-line reading of the chain. Such known measurement devices thus provide a measurement of the degree of wear over a chain or multiple chain sections. The length of a section of chain may be determined by detecting the leading ends of selected center links and knowing the speed of the chain along the conveying path. The speed of the chain and the time between detections may then be used to calculate the distance or length of the section of chain. This length may be monitored to approximate the wear in the pins and/or links of the sections of chain. However, the center links are typically forged members and may have variable lengths due to the manufacturing tolerances of the center links and surface irregularities of the links. Further, the speed of the chain may vary from a nominal speed as the chain moves along the conveyor path. Such chain characteristics and speed variations may result in a high variability in the measured length of the chain links or sections of chain.
Therefore, there is a need in the art for a conveyor system that overcomes the short comings of the prior art.