Pusher assembly for a turntable employing plural stepper motors

Abstract

In a stacker turntable used to form compensated bundles, a drive assembly for moving completed bundles off of the turntable comprises first and second drive motors mounted to the underside of the rotatable turntable at equally distant locations from the center line and as close thereto as is practicable to minimize the offcenter mass. The locations of the motors are balanced to balance the rotatable mass. Each motor drives a 'picket fence' assembly, each assembly being a movable wall formed of individual vertical slats. Pusher elements are arranged at spaced distances among the slats to cooperatively form end guides for supporting bundles as they are being formed and during the time that they are rotated for pushing a completed bundle off of the turntable. The leadlines of the motors extend through a hollow center support and coaxial with the turntable center of rotation to prevent any whipping of the leads during turntable rotation. Each motor comprises a stepper motor which is accurately stepped during operation to assure cooperative synchronous movement and further to provide simple adjustment of any undesirable offset condition and to simplify initialization thereof. Novel mounting assemblies provide simple, straightforward tension adjustment for the timing belts coupling each motor to its associated 'picket fence' drive gear.