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Locking ball joint

leeko

Stainless
Joined
Jun 30, 2012
Location
Chicago, USA
Hi everyone,

I'm working on a design which requires a small joint with 6 degrees of freedom, and also the ability to lock the position of the joint when needed.

I've seen locking ball joints on very cheap indicator stands, that look like a ball bearing sandwiched between two plates with hemispherical depressions in them. The joint is locked down when the plates are screwed together.

I haven't seen any more robust/higher quality versions of a locking ball joint, though. I'm sure they exist, but I don't know the name or what to search for. Can anyone point me in the right direction? The size of the joint would require at most a 1/2” ball, and the more compact the other components, all the better.

Edit: the only example I found would be the ball mount on e.g. a panavise. But that is still too bulky. I'm wondering if there's a ready made component/fastener available, or if I would need to make something.

Thanks in advance,

Lee

Sent from my SM-N960U using Tapatalk
 
Details would be nice. How heavy are the loads, what accelerations must they resist and how big are the moments?

Sent from my SM-G973U using Tapatalk
 
The Mitutoyo indicator set I have has a "collet type" ball clamp with a threaded thimble closer.

I can say where to find them else where, but alternate designs exist!
 
Like this? Also did a search for "balljoint vise" and came up with a lot of ideas...
 

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I have a Wilton Pow R Arm swivel assembly. It is the large model with hydraulic actuation. I has been stored outside. If you want it, just pay me for shipping. I am not sure the cylinder bores are not pitted.
John
 
Thanks everyone for the advice. Tapatalk plays weird sometimes, so I didn't get any notifications until illinoyance's post - sorry!

Illinoyance: thanks for the offer, but a powrarm will be way too big for my design. My balls are around 1/2” diameter or smaller (fnar fnar).

I think after digging around and using some of the search terms suggested here, the best compromise will be 2 balls sandwiched between two plates with spherical seats, and a single screw in the center to tighten. Along the lines of a 5 axis mill stop.

The loads it will see are very light - it's more of a guide arm, but it will have to resist some vibration.

Thanks again,

Lee

Sent from my SM-N960U using Tapatalk
 
Hi everyone,

I'm working on a design which requires a small joint with 6 degrees of freedom, and also the ability to lock the position of the joint when needed.

I've seen locking ball joints on very cheap
The locking ball joint has only 3 degrees of freedom. Pitch, Roll and Yaw. It has no translation freedom. X, Y, and Z
...lewie...
 
Thanks for the correction Lewie, you're absolutely right. I ended up using a double ball joint to give the needed additional movements

Thanks,

Lee

Sent from my SM-N960U using Tapatalk
 
Other folks have already mentioned that smaller (e.g., under 3/4" diameter) locking ball joints are used a lot in photographic accessory mounts and also in professional audio mounts. One refinement I've seen on an Audio-Technica double ball joint (AT8459) is three small, crisp-edged grooves machined in the face of the ball, presumably to give a bit more "bite" to the holding (more likely this serves as relief of minute high points to allow better contact).
 
In addition to pro audio and video, try looking at mobile PC mounts for cars and trucks. They might be a middle ground between hot-shoe video mounts and PanaVise stuff.

Also, video mounts are available in 3/8-16-level stuff, in addition to the lighter-duty 1/4-20 stuff.
 








 
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