Servo motor with hollow center of rotation section ?

I'm looking for a servo motor with a hollow center section of at least 0.5 inches diameter. I want to place an optical polarizer there
through which light will pass and be able to rotate the polarizer about its center axis. Alternativley, a servo mechanically coupled to such a hollow holder. A servo because it is easy to define and control the optical angle.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 29 Oct 2004 14:55:01 -0400, Steve Parus

You could use a setup with bearings on the outside with a hole in the center, and have the servo rotate the center race which has the filter attached. Could be as simple as a ball bearing with a 1" center hole, or a plastic lazy susan from Walmart (bearing tolerances a little lose on this!).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You can buy such things from the usual optical supply houses, Oriel or Meilles Griot. They both sell precision optical positioning servo systems. Expensive, but precise.
                John Nagle
Si Ballenger wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Newport sells one for USD$7500.00 http://newport.com/store/product.aspx?lone=Motion+Control&leveltwo=&idD12&Section=Pricing
I think you can do better though.
look for "360 degree rotation stages"
Opto sigma has a non-motorized one for USD$500 http://www.optosigma.com/miva/merchant.mv?Screen=PROD&Store_Code=OS&Product_Code=pg332-333&Category_Code60+Degree+Continuous+Rotation+Stages
Thor labs has a beautiful one for USD$2890.00 http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID64&Product_ID5101
--
- Alan Kilian <kilian(at)bobodyne.com>
Director of Bioinformatics, TimeLogic Corporation 763-449-7622
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Most autofocus cameras have an aperture / ring servo type of arrangement in the case (if it`s a compact), but also actually in the Lens (if it`s an SLR). It might be worth dismantling one of these if you can get hold of one really cheap. ----------------------------------------------------------------------- Ashley Clarke -------------------------------------------------------
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
www.servocity.com has geared servo units that would work with a little added machining for things. www.robotzone.com has gears, chains, sprockets that could be set to do stuff like that too.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.