#6 Cog and Hammer

'Cog and Hammer' is an ingenius piece of engineering design from Great Willbraham School CE Primary School in Cambridgeshire. It shows a series of connected cogs which trigger a fake finger pressing the key.

Scott’s design for this mechanism is very well thought-through: he’s shown a detailed support frame, describes the gears carefully, has a clear idea for the paddle for the player and the hammer at the keys, and even shows a lovely flower on the piano!  When we thought about making the design work, we were worried about friction: with 34 gears between the player and the piano, it might require a really big force to make all the gears turn.  So, we’ve made a small change to connect the player’s paddle to the keyboard hammer with two long ropes. All the gears in-between are mounted on small pulleys which are turned as the rope moves, but the gears don’t actually touch each other, so we don’t have a problem with friction. As Scott suggests, the gears are cut from thin plastic sheets, using a laser-cutter.