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One advantage of this design is that a single pull-wire is all it takes to execute the metamorphosis from foot to hand and back. The top segment of each finger-toe is rigidly fixed to the lower leg, and the lower segment swivels on an axle or hinge.
Foot. When the pull-wire is relaxed, the springs on the toe-fingers retract and open the lower segments to form feet. Stops can set the final open positions for the toes, and the springs might be designed to allow the toes to bend back for additional compliance during foot-fall. The rubber pads help cushion the shock of foot impact.
Hand. When the pull-wire is retracted, all 3 toe-fingers rotate uniformly [in the simplest design], and the movable segments form into a closed hand. The rubber pads help hold any captured objects. In a practical design, the rubber pads would probably cover the entire contact surface of the toe-fingers, and channels would be cut to guide and protect the pull-wires. Pressure sensors on one of more fingers could signal the presence of captured objects. Obviously, a wide range of hand closure positions is possible, and with a 3-finger design, objects would be centered automatically.
Miscellaneous. The hand-feet are shown rigidly attached to the lower leg here, but they could be made movable on a more complex implementation. Also, a complex design might use separate retraction devices on the pull-wires for the 3 toe-fingers.