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From: nagle@netcom.com (John Nagle)
Subject: Re: Need help in finding large sized Screw actuators
Message-ID: <nagleECr336.JDz@netcom.com>
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Date: Thu, 3 Jul 1997 15:59:29 GMT
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cschumacher@ccis.com writes:
>I am looking for long screw actuators (8 ft min, 12 ft desired) that I can
>purchase to assemble a device to provide motion to a small target (12
>lbs).  This is for an experiment for testing a radars tracking
>capability. The plan is to drive the actuators with small computer
>controlled stepper motors to provide accurate positioning and motion.
>About the only thing I have found so far are used in garage door openers,
>about 8 ft long.  The disadvantage of these devices are they are metal and
>may cause unwanted reflections that will disturb the tests.  Also they
>appear to be several degrees of overkill for the weight being moved.  I
>would rather them be non-metalic, (ceramic, nylon, composite, etc).  I
>would appreciate a lead as to who to call or where to find a source.

      You can get nylon rod from Polymer Plastics Inc (800-968-2212)
or Plastics SRT (415-998-0100), but you'll probably have to thread it
yourself.  (From Mechtronic Buyers Guide (408-738-3020))  Most
standard leadscrew assemblies are metal.  Berg (1-800-455-BERG) has
metal leadscrews, plastic nuts, threaded nylon rod, and does custom
fab.  You could probably get them to make you some of their standard
linear motion assemblies in nylon or Delrin.  They also have a good selection
of toothed plastic chain, and you can order it with an aramid core rather
than the usual stainless steel.  You can run the stuff on Delrin sprockets
on nylon rod, so you could build a completely nonconductive system that way.

						John Nagle 

					John Nagle
