Single gripper conveyor system

Abstract

Gripper assemblies are moved past a pick-up station by a chain conveyor. A conveyor overlapping signature stream moves past the pick-up station beneath the gripper assemblies at a faster linear velocity whereby the leading edge of each signature enters into the open jaws of a gripper assembly. A closing cam closes the cooperating gripper jaws which firmly grip the leading end of the signature as the gripper assemblies enter a curved path thereby abruptly accelerating the gripped signature and the next upstream signature resting thereon to facilitate and enhance its entry into the region between the open gripper jaws of the next upstream gripper assembly. The signature stream is delivered to the pick-up station by a conveyor having a cooperating vacuum source for retaining the signatures in proper alignment upon the conveyor belt as they approach the pick-up station, the vacuum condition terminating before the signatures are gripped by the jaws of a gripper assembly. Each gripper assembly includes a wrap spring which normally holds the gripper jaws closed and which is activated when a gripper assembly release ring engages an opening cam preparatory to receipt of a signature. A closing lever lifts the opened jaw, by engagement of its roller with a closing cam to firmly grip the signature therebetween. After the gripper jaws open, they are maintained open by the spring wrap clutch, enabling gripper assemblies to be slectively released at the drop station, if desired. Signatures are dropped at a drop station by engaging the release ring with an opening cam to drop the signatures onto a receiving conveyor.