The WB Transfer is used mostly in automation to move parts from one place or machine operation to another. Over the years I have been involved in various walking beams, this one bering the smallest, the largest being nearly a hundred feet long, used to move auto body panels from one stamping press to another. Most used hydraulics or pneumatics to power the lift and transfer motions. This one used a single cam.
Moving ball bearings is a little bit of overkill as they are usually just rolled from one place to another, but they worked out well for demonstration purposes.
I built a larger version using dual cam followers and the single cam to move individual solenoid coils, carefully oriented, through a video inspection station then on to a chute. The parts were placed by an operator at the beginning of the transfer, and about half way down, the vision system evaluated 2 solder joints on the coil. I added a complication in the form of a third cam follower and linkage and solenoid operated release latch that was would tip a defective coil off the walking beam if the vision system detected a defective solder joint.
I have sent videos that will eventually show up on the Digital Machinist website, and the project will be the subject of a future upcoming article.