+articles+

prototype = monkey automaton

This prototype Automaton originally seemed very simple but became more complicated with the added weight of resin head, hands and feet. Although they seemed relatively light, they made the armature droop and hard to move. Extra counterbalancing springs were needed to bring it back into balance. Since this is a working prototype, the parts are made of scraps of wood and other materials on hand; everything is light duty and not meant to last but only to see if the design will work.

The controller designed for this Automata prototype is a stacked crankshaft, chosen for mechanical flexibility (varying speed and direction). To test the mechanism integrity, all the holes are roughly eyeballed and glued together. This showed promise, so the next step was to machine the parts with precise measurements and use more robust materials. My desktop machine shop enables me to make parts, which are accurate within tolerances of a thousandth of an inch. This includes a lathe, milling machine; cut off saw, jigsaw, jeweler drill press, and all the cutting tools that complete the set up.

To make the crankshaft strong and accurate, the discs are center drilled using a miniature lathe -- this hole becomes the reference point for the other disc measurements. I originally thought the crankshaft would not require this degree of accuracy, but the holes that link the parts required techniques used in gearcutting. The machine tools have digital readouts so accuracy is assured if the piece is set up and clamped carefully. A keypad is used to advance the discs to the keyed in position. The parts can be drilled safely using tools like this because all setups are done without the cutting bits in motion.

The next stage is silver soldering the discs to create a concentric crankshaft that will not wobble and wear out the bearings. Another disc is used as a handle and the finished controller is polished. This type of controller will enable the mechanism to be cranked in either forward or reverse, and at varying speed.

The almost complete armature before final cabling. The cables are made of 49 hair fine steel threads sheathed in nylon making them very strong. This type of cable is available in jewelry supply stores for stringing beads. The crimps used to attach them to the crankshaft are silver tubes, which are tightened using special crimping pliers.

The next step is designing clothing that will not restrict the movement of the Automaton. Chris and I have to work very closely together at this stage, to make sure the automaton figure will retain the desired movement. Sometimes it may be necessary for the clothing to dampen (confine) certain motions.

Here is the finished Automaton. What initially started as an experimental prototype design became this one-of-a-kind Monkey Automaton, the first of a series. The internal crankshaft design enables the brass hand-crank mechanism to operate at varied speed, in forward or reverse. The Monkey figure moves in a rhythmic side-to-side motion with alternating leg kicks. The loose jointed arms are secured to the legs which creates the illusion of more movement without having to add to the mechanism.