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Worm gear for translation rather than rotation 3

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jande

Mechanical
Dec 3, 2004
5
I'm wondering if worm gears are ever used to produce translation rather than rotation. In other words, can the teeth that would normally be hobbed onto a wheel be cut onto the length of a shaft.
 
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Not certain if I understand your
request. But a helical rack might
do what you are suggesting mated
with a threaded shaft.
 
Essentially I am looking for a method of translating a shaft similar to the helical rack that you're describing. The worm would function the same way it does in conventional applications, but the wheel would be replaced by a rack. The reason that I was wondering about a worm was because I would like to get as much reduction as possible and because it would resist backdriving.
 
I think it would be a rather unique application, but there is no reason you can't use a worm to drive a rack. I bet any experienced gearing company could make the parts for you.
 
Could two parallel threaded shafts give you what you need? You could use something like a single start acme thread. One will translate motion to the other and there would be no backdriving.
Essentially, I think, what you're asking for is a wheel of infinite diameter to mate with a worm. This is of course possible although, in answer to your question, the "rack" can not be hobbed or fly cut as you would cutting a wheel. Your options are; form milling, gear shaping, wire cutting.
 
Sure sounds like a machine tool lead screw to me! Some turn the nut over the screw too if that's what you need.
 
Hi Jande,
In answer to your original question, it seems that a Crescent (R) wrench or a worm drive hose clamp would come close to what you describe.

 
You will need to find a way to avoid interference between the rack and the bearings for the worm.
 
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