Power And Free Conveyors

Also in the overhead family of devices is the power and free conveyor. It's like a regular motorized overhead system, except it has two tracks. In one track, the chain is continuously running. In the other track, the trolleys move along with the chain using pusher mechanisms (known as “pusher dogs”). They’re mounted at regular intervals on the chain. When two trolleys are pressing against each other, the dogs can slide over the top. Likewise, a stop blade can be used with a pneumatic cylinder to replicate this geometry. This allow trolleys to start or stop movement virtually anywhere in the system. This versatility makes power and free conveyors the most productive style of overhead systems. They can start, stop, buffer and re-sequence parts with switches.