Step feeder

According to Brian Davis' lexicon, a great ball contraption step feeder has a series of vertically oscillating ledges or steps, each just a little bit higher than the preceding step. The first step lifts a ball out of the bin, and at the top of the lift the ball rolls onto a static step with another moving feeder step on the other side, which repeats the process. Steps can be driven by cams on a central drive shaft at the base (or partway up)^Davis. Steps in fact can be any width or length down to the nominal size of a single ball.

Variations

• single-acting: odd-numbered steps oscillate up and down synchronously, while even-numbered steps are stationary (passive "holding pens"). Since all the moving steps are synchronous, they can all be part of one structure, moved by a cam at the base. It is also possible, if the step is the width of a ball, for half the step to oscillate and the other half to be static.
• double-acting: every step moves up & down, with alternate steps 180 degrees out of phase, potentially much faster.

Examples

MOC	builder	explanation given	image available	video available	instructions available	follows GBC standard
RODII	parda	no	imgur	no	Brickshelf LDD	yes

External References

Davis - The Great Ball Contraption