Slip Ring help needed

[JasonEm]

Hello and thanks for checking this forum ...We are designing a swivel for use in helicopter longline work, and are wanting to transfer an electrical signal through the rotary joint. Yes, there are a lot of slip rings out there on the market, but we have space constraints (OD 2", ID 1", Stack height >.5" - transferring a signal of 24-26 volts @ 7amps max. - noncontinuous signal). We are looking to isolate two electrical paths through the swivel and are looking for alternatives to what seem to be an endless supply of costly products. Just curious if anyone out there has worked on something like this before and has any suggestions/leads?

 

[EdDanzer]

Your space requirement will limit choices. The mercury contact type may be your only choice short of a special design.
Can you use the cable as one (ground) conductor?
Does it have to continuiously rotate or can it be limited to less than 360° rotation?
How fast does it rotate?
Will this .5” height include alignment bearings? If so, you will never get anything to fit at a reasonable price.
A rolling ring may work if the mounting envelope could be rectangular in shape and have more space away from the center of rotation.

 

[JasonEm]

Thanks for replying to this thread EdDanzer..Since posting the thread I might have a solution...but to answer your questions:
Though I can't use the cable as a ground, I can use the swivel body as one of the conducting paths. The slip ring will have to continuously rotate but the maximum rotational speed would likely not exceed 40 rpm. The space does not make room for bearings, thought there are bearings throughout the swivel to ensure that alignment is maintained.

http://www.jmney.com/cap_stamp.htm

This link shows the kind of contact that I think I'll use to join the electrical signal to an insulated copper path on the central shaft.

I haven't heard about this 'rolling ring'..but will do a couple searches..

Thanks.