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Illustrations of the inner mechanisms of the DANGAERI doll

In the following figures, a doll is watched from the side because of the easier understanding of the principle of a back flip, referring to a commercial doll. The mercury is replaced by three iron balls and the tube in which mercury moves is substituted by a pipe which passes the head and body of the doll. The "C" in the figures means a center of rotation and the "S" means a stopper.

  1. There are three balls in a head of a doll at first. Then the moment, which is centered at C1, occurs, and the entire doll turns over anticlockwise.
  2. The palms touch down and then the doll turns over at point C2.

(2)

(1)
  1. The legs turn over at point C3 anticlockwise from the turning of the entire doll, and then, the body and legs align with each other.

(3)
  1. A moment centering at C2 becomes bigger, and the legs come down lower than the head causing the balls to move down in the body. The doll continues turning until it reaches the next step down.

    --> Animation from (1) to (5)


(4)

(5)
  1. A moment centering at C4 occurs when the legs reach the lower step, and then the upper part of the body turns anticlockwise. By the inertia moment, the turning continues the doll turns beyond the balance point, and the entire doll returns to position (1). The doll repeats the exercise through stage (1) to (5) until there are no more steps.

    --> Animation from (5) to (1)