NetNews Usenet Archive 1992 #20/NN_1992_20.iso/spool/comp/robotics/1800

Text File | 1992-09-15 | 3.3 KB | 84 lines

Newsgroups: comp.robotics
Path: sparky!uunet!gatech!asuvax!ennews!mcdphx!hbg6
From: [e-mail] (John Schuch)
Subject: Re: defn. "slip ring"
Message-ID: <[e-mail]>
Keywords: slip ring(s)
Sender: [e-mail]
Nntp-Posting-Host: bopper1.phx.mcd.mot.com
Organization: Motorola Computer Group, Tempe, Az.
References: <[e-mail]> <[e-mail]>
Date: Tue, 15 Sep 1992 13:11:01 GMT
Lines: 70

In article <[e-mail]> @ccs.carleton.ca writes:
>In article <[e-mail]> [e-mail] writes:
>
>>"slip ring [ELEC] A conductive rotating ring which, in combination with
>>a stationary brush, provides a continuous electrical connection between

>If that's the case, would the following work ...
>
>Using printed circit boards, as described elsewhere, etch the a series
>of circles on the boards. Use small ball bearings as brushes and the

I have built one that worked fairly well but it was a little complicated.

Last chance to bail out before the long-winded explanation.


First obtain a short length of copper tubing and a phenolic/plastic/com-
posite or otherwise non-conductive rod. The non-conductive rod should
fit inside the tubing snuggly but you should be able to slide the tubing
over the rod with little dificulty. I used 1/4" I.D. tubing and a
phenolic rod. I turned the rod to the appropriate size on a small
bench-top lathe.

Obviously the rod/tubing combination will be the rotating member.
The assembly I made had 4 conductors but this method could be used to
make much larger assemblys.

Carve four channels in the side of the rod displaced 90 degrees from
each other. These channels should be slightly larger than the wire
you are going to use.

Cut off four 1/4" lengths of tubing. These pieces should not be deformed
and should still slide over the rod. make sure the edges are smooth
and free of burrs.

Cut 4 pieces of wire, each about 6 inches long. Strip about 1/16"
of insulation from one end. Solder that end to the INSIDE of one
of the pieces of copper tubing. Make the solder joint as small as
possible.

At this time you should have the rod with four channels in it,
and four little pieces of tubing each with a piece of wire soldered
to the INSIDE.

Mix up a small amount of two-part non-conductive epoxy. Slide one
of the rings ( copper tube piece with wire ), with its wire in one
of the channels about 1 inch up the rod. Apply a coat of epoxy to
the rod NEXT TO the ring, then slide the ring into the epoxy.

Slide the next ring onto the rod with its wire in the next channel,
and over the previous rings wire. Move it to within a half inch
of the previous ring, apply epoxy, slide ring into place.
Repeat this step for remaining rings.

After the epoxy cures, place the rod assembly in a small lathe and
and place a VERY SMALL 'V' groove in the center of each ring. Then
polish the assembly taking care not to harm the wires.

I dismantled several small electric motors and took their brush
assemblies, which are actually spring-steel wires, and used them
for the wipers.

This worked very well for my application, hope it helps with yours.

NOTICE: Granted, this method is not for everybody. I is best suited
        to someone who has a lot more time than money. Unfortunatly
        I seem to be a life member in that club.

John Schuch