Power and Free systems
Power & Free conveyors are based on a twin-track system. The top track is used for the power chain and the bottom track for the carrier trolleys. On an equal pitch pusher dogs are fitted in the power chain and are used to pull the carriers around the system. The movable cams of the pusher dogs latch onto the trolley to form an interlink connection.
Stop stations are used to disengage the link between the power chain and trolleys. When a stop station is closed the carrier will stop while the power chain keeps moving. Because of the pusher dog and trolley design multiple carriers can buffer behind a stop station.