Electrical Connection Linear Slide? Does this exist?

[drozovs]

Hello,

Does anyone know of a device similar to a slip ring but instead of rotational translation allows for linear movement? I have a design that requires an assembly to move ~6 inches along a rail and the unit has 20 leads currently on a ribbon wire to allow for the translation. Does anyone know of a device that possibly has a sled or other method that I could solder to so I dont have to worry about the wire binding issues found with ribbon wires? The wire leads are all signal level leads so major current. Thank you in advance!

-David

 

[IRstuff]

I think that you'll probably find that a linear "slip ring" probably has more mechanical reliability issues than you'd get from a ribbon. Additionally, one might expect that repair of a ribbon assembly would be substantially easier than with what you're asking for.

TTFN

FAQ731-376

 

[drozovs]

The problem is that I have not been able to find a single linear "Slip Ring". ALL of them are Rotary and the conductor bar systems are too large for the application. Do you know of any systems out there? Thanks!

 

[jraef]

Are you looking fr information on position, or transfer of power?


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[IRstuff]

I think you are having trouble finding examples because of the issues I cited above. Slip rings are mandatory for freely rotating joints; there are no alternatives.

You might take a stab by contacting slip ring suppliers that might make custom assemblies:

http://www.sliprings.com/company.htm

http://www.moog.com/capabilities/building-blocks/

http://www.hubbell-gleason.com/EngProd/SlipRing.html

http://www.schleifring.com/en/Products/index.php

TTFN

FAQ731-376

 

[MikeHalloran]

Please Red Flag your request in Electric Power Engineering and ask that it be deleted.

My careful reply there adds nothing that hasn't been suggested here.



Mike Halloran
Pembroke Pines, FL, USA

 

[drozovs]

I am just looking for transfer of power.

None of the slip ring manufactures make a device for the linear (non-rotational) translation. Any other ideas?

Considered it red flagged, thanks!

-David

 

[MikeHalloran]

You've got me confused.

For power, e.g. <5 conductors, and such a short stroke, you could just use braided wires and let 'em flop around.

But 20 conductors suggests some small signals, which you might have to amplify to pass through a slip bar, assuming you could get such a thing.

What do you mean by 'ribbon wire'?

If you mean multiconductor flat cable with very thin (and relatively wide) solid conductors, laminated in mylar, equipped with good strain reliefs at both ends and 'rolling' between planar surfaces like a 'Rolamite' (remember them?), then you're already doing all that's possible, and should get effectively infinite life.

If you're using generic stranded ribbon cable and/or not paying extreme attention to strain relief, then, well, you're not going to be happy.





Mike Halloran
Pembroke Pines, FL, USA

 

[ScottyUK]

Have a look inside an inkject printer at the printed ribbon assembly for an example of what Mike is talking about. They are designed for fairly high speed operation and give pretty good long-term reliability. I've never known one fail other than through mechanical damage.


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If we learn from our mistakes I'm getting a great education!

 

[drozovs]

Sorry, what I meant through power transmission was that i do not need position (like as in a voltage divider). I currently do have a ribbon wire installed but I really would like a track set up with the leads. I only have about a half an inch of height within the assembly and there are parts that might interfere due to how many moving pieces we have. The ribbon wire will work, its just not the best solution.

Does anyone know if there is a slip ring like device but that instead of rotary translation is laid out flat so you could move one assembly forward and aft and the other remains stationary? Much like an electric train on its tracks.

My goal is to replace the ribbon wire and not go to a wireless solution.

Thanks.

 

[MikeHalloran]

To our knowledge, there isn't such a thing.

There could be such a thing.
HOW MANY WILL YOU BUY?
For a couple million a year, you can probably get what you're asking for. For lower volumes, you'll have to participate in the non-recurring costs somehow.

CAUTION; your questions suggest that what you ask for may not be what you want. You seem to be fuzzy on the differences among power, analog, digital, and signal/sensor lines. You need to get a sparky involved before getting all tooled up. Someone who can explain 'source impedance' to you in English can probably help.



Mike Halloran
Pembroke Pines, FL, USA

 

[dpc]

Any sliding contact, whether linear or rotary will be problematic compared with a ribbon cable. There's probably a reason every inkjet printer has a ribbon cable.

Much engineering effort has gone into eliminating sliding contact surfaces over the years. Even many overhead cranes use cable reels and other methods to eliminate the bus system.

Electrified trains use their pantographs and catenaries because they have to. But they require a lot of maintenance, even with several thousand volts to punch through oxidation, air gaps, corrosion, etc.

 

[drozovs]

Sounds good. I can cope with the ribbon wire though I wish I could find a track and slide assembly for the signal connections. Might not be in the cards. Thank you all for your input.

Best,

David

 

[StephenVB]

I would imagine you could just use standard brushes and holders on round rods, but I'm not sure it would work if the current were low and you might have issues with exposed conductors.