I need to energize an assembly mounted on a machine that has a rotary stage. This stage has several pneumatic components that will in turn be actuating a few mechanisms. I need to find an electrical connector that would be automatically engaged/disengaged from this assembly using a pneumatic actuator. To avoid using too many cables, I've decided that the best way to go around it is to mount the controller on the rotary stage itself. That way only ground, power (which will be regulated and current-limited 12 VDC) and a couple of differential communication lines would be used. That is, only six cables would be needed, plus a pneumatic (about 90 psi) line.

Question, (leaving aside the need for a pneumatic line for the moment) is there a connector out there that could be used for this purpose? Maximum current drawn through its power line would be about 1 amp. As has already been mentioned, the connector would be engaged/disengaged by a pneumatic actuator. So it has to be able to tolerate small misalignments, and should not be of the locking type. The number of daily cycles would be significant, in the order of a couple of thousand.

@MaxHeadRoom , this little challenge might be of your interest.

 

You might want to look at rotary type connectors along these lines if that would work. Similar to a slip ring type design as used in automotive alternators. I have seen the same type brush and slip ring design used in rotary torque transducers and servos.

I have also seen plenty of pneumatic rotary couplers. What sort of rotational speed are you looking at?

Ron

 

@MaxHeadRoom , this little challenge might be of your interest.

Oh yeah, as though I don't have enough pressure!

Do you mean some kind of rotary commutation device? or am I miss-reading the concept?
Max,

 

my first impulse was to propose some sort of slipring but then i re-read it and now i think that is not what was asked. i have worked on many projects including automotive where connectors on car seats were connected/disconnected hundreds of time a day with some compliance (not a precise position). in all such cases we used pogo pins in a plastic block shaped to engage and line up with the target connector. in some cases connectors were latched so power seat could still move during tests (fwd/reverse, up, down etc), in others, connectors were on the pallet that seats are placed on (no locking connection, just spring-loaded pogo pins in a block moved by a pneumatic cylinder).

 

by the way... what kind of "rotary" stage? something that always turns same way or something that indexes back and forth? maybe all you need is flexible cable.

 

To clarify, the rotary stage is ring-like (not plate-like), so using a rotary connector is out of the question. The connector has to be located on the outer edge of the ring, and will be engaged/disengaged from the outside of said ring using an actuator. Fortunately, rotation position is very precise, so at least that part is covered.

I'm beginning to like the sprig loaded pogo-pin connector idea. Any idea on where I can buy said pins?

Max, here's an excellent article for you on how to handle stress.

Thanks all for your excellent help.

 

check amazon https://www.amazon.com/s?k=pogo+pin&ref=nb_sb_noss_1
or OctoPart https://octopart.com/search?q=pogo pin
which collects info from major electronics distributors.

 

Btw, pogo pins can also have different stroke, head shapes etc. (pin, crown, cup, sphere etc.). also they can have optional receptacles (pin holders). Those are like sleeve that gets pressed into drilled insulator block. back side has solder cups. then it is very easy to place or replace damaged pins. (pull old one out, place new one in). If you don't need high density (well, you only have few contacts), consider using larger pins and spacing them out.

 

Does your rotary table need to go more than 360° or continuously rotate? If yes, then a slip-ring approach is what I have seen. If not, a "clock spring" can be used and probably is less electrically noisy. Both approaches are used to connect steering wheel electronics to the rest of the car.

I love going to junk yards. Might be a good place to see what's available. You might also consider just putting power to the table and doing the signals wirelessly.

 

I love going to junk yards. Might be a good place to see what's available. You might also consider just putting power to the table and doing the signals wirelessly.

Tell me about it. Are you familiar with HGR Industrial Surplus here on the East Side of Cleveland? I can't remember which day but during summer months they grill hamburgers and hot dogs outside for visitors. Anything from heavy machinery to lab equipment piled up all over the place. While I was still working at the old TRW Plant on Euclid avenue in Euclid a few of us would take an extended lunch and wander over there for lunch and see if we saw anything the department needed or could use.

Ron

 

Tell me about it. Are you familiar with HGR Industrial Surplus here on the East Side of Cleveland? I can't remember which day but during summer months they grill hamburgers and hot dogs outside for visitors. Anything from heavy machinery to lab equipment piled up all over the place. While I was still working at the old TRW Plant on Euclid avenue in Euclid a few of us would take an extended lunch and wander over there for lunch and see if we saw anything the department needed or could use.

Ron

Grill day used to be Wednesday. Haven't been up there for years though. Wasn't the HGR building a GM transmission plant at one time?

 

Max, here's an excellent article for you on how to handle stress. .

Nah, have to give up Alcohol and caffeine!
Thanks anyway.
Max.

 

Grill day used to be Wednesday. Haven't been up there for years though. Wasn't the HGR building a GM transmission plant at one time?

It may have been, it's a big place. OK, Wednesday it was then. No clue if they still do that. I have been snooping for a cheap but good slotted weight set that will get me up to about 70 LBs or so. The old cast types.

Ron

 

Does your rotary table need to go more than 360° or continuously rotate? If yes, then a slip-ring approach is what I have seen. If not, a "clock spring" can be used and probably is less electrically noisy. Both approaches are used to connect steering wheel electronics to the rest of the car.

I love going to junk yards. Might be a good place to see what's available. You might also consider just putting power to the table and doing the signals wirelessly.

Thanks, John. The table does indeed rotate continuously, but I can't use a slip ring due to its size, its industrial surroundings, and its outside border's geometry (it has a few screws protruding from it). Also, using batteries for it to be self-powered is out of the question, since periodic battery replacement would be a no-no, and making special contacts to recharge them would leave us with the same initial problem. And we're still left with the issue of a pneumatic line engagement/disengagement So connection to the outside world has to be done after each production cycle (which is a little less than a minute) has been completed.

So far, @panic mode 's approach is the one I like best. Which leaves me only with the pneumatic connection problem to be solved, but I think I'm beginning to have the glimpse of an idea about that at this point. I'll be right back with a schematic... see what you guys think...

 

These https://www.uweelectronic.de/en/prueftechnologie-kontakttechnologie/federkontaktleisten.html guys have them "cobbectorized as an assembly"

I've use the standard pogo probes for high temperature (200 C), low temperature (cryostat) and even low speed sliding contacts (model gantry grane). As was said, there are housings which I've never used that make the contacts instantly replaceable. The probes used at high temperatures (200C) didn't like being soldered, so the electrical connections were done mechanically. In one case, I used them in a 20 K-gauss Hall Effect set-up. I made sample holders on microscope slides.

The standard probes were initially ordered from a distributor and then Newark Electronics.

 

Tell me about it. Are you familiar with HGR Industrial Surplus here on the East Side of Cleveland? I can't remember which day but during summer months they grill hamburgers and hot dogs outside for visitors. Anything from heavy machinery to lab equipment piled up all over the place. While I was still working at the old TRW Plant on Euclid avenue in Euclid a few of us would take an extended lunch and wander over there for lunch and see if we saw anything the department needed or could use.

Ron

Yep, I have been there many times and rarely leave empty handed. Came very close to picking up a Monarch 10 EE. It's just fun to browse. (Used to live in Mayfield heights, which was more convenient.)

 

Im not sure I understand what you need but I thought I would give it a try:
https://www.aliexpress.com/item/32838124242.html?spm=a2g0s.9042311.0.0.27424c4d2CLRbn

 

@cmartinez, did you look at Han connectors (ie. 09140034501 etc.)
Harting has modular connectors that mix air and electric signal. You can remove latch and use cylinder to actuate it.
Or use just inserts without Harting connector shell

 

@cmartinez, did you look at Han connectors (ie. 09140034501 etc.)
Harting has modular connectors that mix air and electric signal. You can remove latch and use cylinder to actuate it.

View attachment 180922

View attachment 180923

Sounds interesting... but I'm going to check their tolerance to misalignment... I'm thinking I might have to design a special shell to which I'll add the pogo pins ... but those pneumatic connectors look interesting, I'm going to check them out. Many thanks!

 

nooooo....

you don't want electrical or pneumatic connectors to take care of alignment.
you would need to add mechanical locating features that align mating sides before they engage.
topically those would be round dowels with some tapering...

so first 20-30% of travel is just approach
next 20-30% of travel is locating
and then rest of the travel is mating of connections.


here is a sketch of such vampire teeth (usually metal) and counterpart blocks (usually plastic).