Abstract: An improvement in a spur gear mechanism having a pair of engageable spur gears, a device for rotating the gears in one direction only, and a device for engaging and disengaging the gears. The improvement includes a chamfer on the top, circumferential surface of each tooth each of the gears. The chamfer starts at the working surface of the gear tooth and extends inwardly toward the juncture of the pitch line of the gear and the non-working surface of the gear tooth, whereby the opposing teeth of the engaging gears do not prevent the re-engagement of the gears when the gears are brought together for engagement.

Abstract: A resilient document feeding member having a drive shaft, and a double D hub fixedly secured to the drive shaft, the double D hub having a pair of opposing flat surfaces. The resilient document feeding member also includes a second hub removably and rotatably mounted on the double D hub, the second hub having a pair of parallel slots which, together with the opposing flat surfaces, define a straight channel, and a pair of resilient arbor flaps, each of the flaps being mounted in one of the channels to thereby frictionally lock the second hub to the double D hub and facilitate quick changing of the arbor flaps.