Power conveyor system for production lines

Claim 1

A power and free conveyor system for moving work holding fixtures along a production line having both automatic and manually attended work stations comprising; spaced parallel tracks each formed with fixed supporting and stabilizing surfaces, a conveyor chain supported and stabilized by each of the tracks on their respective fixed supporting and stabilizing surfaces, inwardly projecting rotatably free rollers having a length substantially shorter than half the spacing between the tracks and supported independently by respective ones of the chains leaving uninterrupted space between the chains to accommodate the work stations, power means for driving the chains along the tracks, work holding fixtures supported on the rollers for movement at speed rates automatically adjustable relative to the speed of the chain to meet the work cycle requirements of the automatic work station, a pair of belts disposed below the rollers in longitudinal and vertical alignment with the rollers to frictionally engage the rollers in the area of the manually attended work station and means to drive the belts at a preset speed rate to move the work holding fixtures through the manually attended station at a speed rate which is dependent on the relative velocities of the belts and the conveyor chains.