This is Percy the "Ping - Pong Porter" a model designed by Chris Shute the Instructions were originally published in The Constructor Quarterly magazine. The automaton that's Percy crouches down, picks up a ping-pong ball, moves up and sideways dropping it on the top rails, before descending and starting the sequence over again. Its a beautifully simple model to construct but considerable patience is required to get the sequence of movements working smoothly. When that is achieved he can run perfectly all day without problems apart from the odd escaping ping pong ball.
My main difficulty was getting his arms to close quickly enough to stop them fouling the top rail where the balls drop as Percy descends to pick up the next ball.
The only changes I made to the original design was to replace the top rail perforated strips with narrow ones this gave a little extra clearance for Percy to close his arms ready for the next ball. I used a small tension spring ( non Meccano) between his shoulder blades instead of a short length of Meccano spring cord. The model was always a big hit when ever I exhibited it. The anticipation that he might drop the ball adds to his appeal especially when ran very slowly.
Revised May 17 2015