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• Constant Force Springs - New Challenges 

Constant force springs have the same qualities as a weight drive, that is almost constant torque over the full wind of the spring. They are small and can be incorporated just about anywhere in a sculpture. No longer would I have to think about a weight drop path or design complicated pulley and string suspension systems. Soon after learning about them, I started using the springs and never looked back. 

The springs opened up another world of things to try. I made small freestanding pieces, like Dyad and wall pieces like Tapestry. Every design now incorporated a spring and in all of these pieces I was able to reduce the mechanism and feature the motion, furthering my design evolution away from a mechanism focus to one of creating motion patterns.


Constant Force Spring closeup on kinetic sculpture by David C. Roy of Wood That Works

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Reader Comments (5)

I love your designs and the fluid motion of your sculptures Id like to create a kinetec piece myself
I understand the principles of your peices (ie the constant force spring motors/ escapement) but Im puzzled as to the black elastic cord you use to operate the pulleys do you use a cord and join it to get the length you need for the pullys or do you use a ready made loop ?
if it is joined elastic cord how do you join it to make it run so smoothly?

February 21, 2013 | Unregistered Commenterrex

Rex, The belts are not elastic cord. Years ago David used to use rubber o-rings but he found in certain environments they deteriorate rapidly ( Like in Los Angeles). So, at the suggestion of a collector, he experimented with springs. The black belts are tightly wound coil springs painted black. They can be cut and hooked at any length. That provided a great freedom in design.

March 8, 2013 | Registered CommenterDavid Roy

I also love your sculptures very much. Such elegance must have taken years of experiments and attempts to obtain. Your art have inspired me to want to create a piece of my own.

I fancy myself as a woodworker more than an engineer, and could use a good guide as to how your mechanics with the constant force spring and escapements are actually physically assembled in any given sculpture. (Like center mounted like "Monarch" or separate like "Frolic")
Ever considered making a step by step video of this process?

March 24, 2013 | Unregistered CommenterKim


Love your art! I wonder how you get the movement to change direction. I understand you use constant force spring, but how to you get any wheel to switch speed and direction of rotation?


February 20, 2015 | Unregistered CommenterMay

Could you tell me about the specification of your constant force spring (thickness, width, elastic coefficent, hardness)?

I tried some type of spring in market for our products but it's not reach constant force like yours.

July 27, 2015 | Unregistered CommenterMinh

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