Rolling Ball Technology
An Online Technical Reference Devoted to Rolling Ball Sculptures, Clocks, and other Devices
By Members of the rolling-ball@lemur.com List

Arms

Edited, and with material by David M. MacMillan

Contents

  1. Simple Vertical Pivots
    1. al-Jazari's Serpent
  2. Transferring Arms
    1. Rhoads' Science on a Roll (The Imaginative Chip)

Simple Vertical Pivots

al-Jazari's Serpent

In his Book of Knowledge of Ingenious Mechanical Devices, completed in Diyar Bakr (in present-day Turkey) in 1206 A.D., Ibn al-Razzaz al-Jazari describes a water clock which employs a brass serpent as a ball-delivery arm. The ball-release mechanism of this clock is described in Ejectors, Releases, and Distributors and the zoomorphic aspects in Anthro- and Zoomorphic Figures, both in the present work.

The descriptions of this mechanisms in the present document is taken from Hill's presentation of al-Jazari's work in Islamic Science and Engineering. Briefly, in this clock ("Category I, Chapter 3) a falcon faces a serpent. At each hour, a ball rolls out of the falcon's beak and out into the mouth of the serpent below. The weight of the ball causes the serpent to tilt down (which in turn cases its head to sink). At the bottom of this tilting, the ball falls out of the serpent's mouth and onto a cymbal. (Hill 130-132, Fig 7.4)

Transferring Arms

Rhoads' Science on a Roll (The Imaginative Chip)

Legal Matters

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Version 2.2, 1998/06/20. Feedback to dmm@lemur.com
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