GRAVITY BALLS Tell EXACT TIME (Nov, 1931)
GRAVITY BALLS Tell EXACT TIME
A CLOCK without hands, which tells the exact time by the rolling down hill of steel balls, has been perfected by a Philadelphia inventor. It required twenty years to discover the secret of accuracy in rolling the balk mile after mile, but on a recent three months’ test run the clock showed a gain of only a few minutes.
The steel balls are automatically released at the top and travel in relays to the bottom on track made by two fine music wires. The mechanism starts a new ball every 2-1/2 minutes. When a ball reaches the 60 mark it enters a trip cage which lowers it onto the hour beam. When 60 balls have descended to the beam it tilts and turns indicator to next hour. The device is especially adaptable to window advertising displays.





Not a bad idea.
The factors determining the speed of the clock are probably the steepness of the slope as well as the friction. You can controll the steepness quite well, the friction is a bigger problem, however.
Comment by Casandro — April 9, 2007 @ 10:30 am
Everything you need to know about ballclocks:
http://www.chilton.com/~jimw/ballclks.html
Get one at:
http://scientificsonline.com/p....._E_3082445
Comment by jayessell — April 9, 2007 @ 4:49 pm
Thanks JSL, cool page
Comment by Stannous — April 9, 2007 @ 9:14 pm
Something is amiss… starts a new ball every 2.5 minutes, but it takes 60 balls for it to change the indicator to the next hour, so wouldn’t it take 2.5 hours until it changed the hour?
Comment by Alan — August 28, 2008 @ 4:39 am