Constant force spring motors

A couple of years ago I came across some constant force spring motors. It was about the time I was reading Alan Timmins' '8 Day Longcase Clock' book. Lo & behold one of the motors gave the same torque output as the weight driven drum in Alan Timmins' book (see www.smallparts.com.au/store/partslist/springmotorsrino/springs/wide/1/ I think the motor was the SR107 but as I'm working from a 5 year old memory I may have the wrong one).

So, it occurred to me that this could drive a spring powered clock with no need for a fusee. However, I have never seen a clock design like this. Have I missed one, have I come up with something new (highly unlikely!) or has it been tried & found to be utterly hopeless?

Regards,

Richard.

Richard,

I'm almost sure that I have seen something about using constant force springs, in the Horological Journal; but cannot remember when.

Try looking for the Trade-Name "Tensator"

MichaelG.

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Edit:   Just found this reference to a Smiths Movement

Edited By Michael Gilligan on 07/06/2013 12:42:53

Micheal,

Thanks fot that. I was wondering if I had gone completely off track, but it seems not to be the case. Rino used to sell these motors in the UK as singles, but since Ondrives bought them out, they don't seem to be available here in quantities less than 10.

Ahh, Well.

Richard

There was some thing in ME some years ago, and it mentioned something to do with V- Bombers, can't remember which one.

Try ME Vol 178 no., 4037, an artical by Peter Spenlove - Spenlove, "Constant Force Springs and a problem solved" / Discusses Tensator Springs.            Ian S C 

Edited By Ian S C on 10/06/2013 12:35:10

Just to let you know:

I have just recieved the latest Ondrives paper catalogue, and the spring motors are in it (even though I cannot find them in the web catalogue).

Regards,

Richard