A power and free conveyor system has trolleys which are mounted on a free track for driving when engaged by pushers on a continuously running power chain. On each trolley, a pusher pawl, lost motion link, and bellcrank lever are interconnected to hold the pusher pawl erect for engagement by a pusher when the lever is in a normal position. When the lever is pivoted by engagement with a preceding trolley, the pusher pawl can collapse. The lost motion link also permits collapse of the pusher pawl on overtaking a pusher.
A center link pusher dog assembly for power and free conveyors includes a pusher dog member with a mounting base and a pusher dog projection upstanding therefrom. The mounting base has depending lugs and a rear shoulder to engage an abutment formed by a reduced central area of a center link of a conveyor chain. A bore through the pusher dog member recevies a bolt for clamping a center link between the pusher dog member and a conventional chain support type of power trolley. The lugs engage upstanding teeth on a mounting end of the power trolley and side walls of the center link to fix the longitudinal position of the pusher dog member relative to the power trolley and the center link and to fix its lateral position relative to the center link.
A releasing device and dog member for a power and free type of conveyor is described. The releasing device includes a rod (105, 205) which is linearly moveable upon engaging a stop or a truck (17) with a buttress plate (105a, 205a) on the rod to disengage a retaining plate (100a, 200a) on a pivotal dog (100, 200), thereby allowing the dog to pivot away from a pusher member (12). An extending device, such as spring (108) or camming member (209), urges the rod to an extended position when the stop or forward truck is removed from engagement with the buttress plate.
