Lego Button Spinner 6-Prong Escapement

Gravity-run mechanical torsion-pendulum oscillator automates the old button-and-string toy, called whirligig or buzzer toy.

The escapement consists of the following components:

1. 6-prong (teeth) escape wheel
2. Locking lever that rests on a pin
3. Vertical pallet that can rock back and forth
4. Arm that rests between the escape-wheel prong and pallet
5. Sewing button (1" OD) strung on a cotton sewing thread
6. Lead bob, 1.875 oz

When at rest, the escape wheel is locked by the locking lever. As the button spins, the string twists and its length is shortened, pushing the vertical pallet towards the locking lever. The pallet then lifts the locking lever and releases the escape wheel. The escape-wheel prong slides down over an arm that in turn impels the pallet away, thereby extending the length of the string. This results in a torque that produces rotation of the button. The restoring force twists the button in the opposite direction, the string length is shortened, and the cycle repeats. The escape-wheel prong impels away the vertical pallet by gradually sliding rather than applying an impulse as in swinging pendulum clocks. Gradual delivery of torque is needed in order to accommodate the moment of inertia of this torsion pendulum. A weight of almost 2 oz was needed to transfer force from the escape wheel to the pallet and convert it to torque. This borderline weight for a Lego structure is obvious when you notice how the entire frame of the escapement vibrates with each strike.

A button Spinner 3-Prong escapement with large physical space between tips of prongs allows for simpler construction of the pallet but is subject to vigorous vibrations.

You can watch other button spinners and torsion pendulums in action at:

8-prong button spinner 360-degree view: https://youtu.be/i6sAWHaZXXI
6-Prong button spinner with force of gravity 360-Degree View: https://youtu.be/4XoJ646-JEE
3-Prong button Spinner with force of gravity: https://youtu.be/42i87nh04As
Coupled button spinner with force of gravity: https://youtu.be/JAq_OU7WOVw
Torsion spring with force of gravity: https://youtu.be/DmwF_GANsmE
Electromagnetic driver: https://youtu.be/Gleg2dWei8E
Electrostatic induction motor driver: https://youtu.be/yL8SlcBac5s