US Patent 7694803 Braking conveyor system

An assembly and method for controlling movement of a chain section during removal, including a mounting body providing a connector adapted for connection to a chain, a pair of rollers secured to the mounting body, the rollers being adapted for rotational movement along the channeled track, and an engaging member positioned between each roller and said mounting body, wherein the engaging member is configured to extend the roller between a disengaged and engaged positions, so that movement of the chain is retarded as the roller extends towards the engaged position.