Image Number 4 for United States Patent #6415911.
A differential impulse conveyor (10, 10A) for moving goods along a tray (12, 12A) in a forward direction at a first speed and in a rearward direction at a second speed greater than the first speed. A reversible servomotor (14, 14A) may be provided for powering a drive mechanism between the motor shaft (16, 16A) and the tray (12, 12A). The drive mechanism may utilize a rack and pinion assembly (30). An electronic controller (68) may control the rotational speed of motor (14) and reverse the direction of motor rotation. Another embodiment may utilize a drive mechanism including a pair of timing belts (79A, 85A) with ends (83A, 89A) secured to respective links (35A, 48A). A further embodiment illustrated in FIGS. 7 and 8 utilizes a cable and sheave system having a pair of cables (43B, 59B) operatively connected to a reversible motor (14B) for moving the tray (12B) in forward and rearward directions.