Mechanical ball and socket joints with specified tension?

Okay mechanical engineers: what I am looking for is a ball and socket joint with a tension rating. The idea is to make a lamp that has an adjustable angle fitting for aiming the light. Is there a name for a metal joint composed of a metal ball bearing surrounded by a sleeve (socket) with a determinable amount of friction, adjustable for the weight of the adjoining object?

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rickharris6 years ago
Your best bet might be to split the cup and put a bolt through so it can be tightened on the ball.

Anglepoise cracked this years ago.

Otherwise cork makes a good friction surface as it can be cut into thin sheets.
+1. Use a nut or bolt which is designed to be turned by hand, and you'll be able to easily adjust the friction to hold more loosely or firmly as needed without having to go find tools. Or, if compactness is more important, just go with a smallish nut and a bolt cut to the minimum length necessary to do the job.

Depending on your needs, you may or may also need to consider texturing the joint components (to hold more strongly) or making them out of a lower-friction material such as teflon (to move more easily)

OR, if you don't need to be able to re-pose it easily and want it firmly locked in place: Standard ball and socket, drilled for at least two setscrews (preferably 90 degrees apart from each other).
Nate Cougill (author)  orksecurity6 years ago
That's a fantastic approach to the problem. Just one more thing to love about Instructables... :)
+1
Nate Cougill (author) 4 years ago
In case someone comes upon this thread later, I have found the solution I was looking for. They are commonly sold as lamp parts and are simply called "swivels." Brass ones are most common. There's a whole spectrum of them, but this is one style: http://www.mylampparts.com/Products/Special-Large-Adjustable-Turned-Brass-Swivel---14-M-x-14-F__SL01905.aspx

Only took me a year and a half to find them!

I'm a student at ccs and I want to say thank you for posting this link! I'm creating a lamp for my product design class and this is perfect. However, I would like to know if this joint grants near a 360 degree movement?

Nate Cougill (author)  fall3R2 years ago

CCS is a great school I dropped out of ID school to start a product design co. Yes, this should give you 360* of motion, though I didn't end up buying one. The plan was to make a pendant lamp from a tympani shell. Send me your portfolio or core77. I would love to see what you're working on.

I have a similar project for an introductory engineering class, I'm in need of some type of swivel joint that can be tightened or loosened to adjust the angle of the arm attached to it. On the end of that arm is a tray table that needs to hold a tablet and a book. (about 5 pounds) On the other side of the swivel joint an arm is connected to a piece resting on the ground. It's essentially an adjustable tray table.

Nate Cougill (author)  jake.geyen2 years ago

Hey Jake. I'm thinking more about this problem after some years away from it. I think that the best approach would be a ball and socket with a threaded cup. If you treat the top and/or bottom of the cut as a conical hollow joint, then the tighter you screw down the top and bottom cups, the stiffer the joint will become.

Screen Shot 2015-01-27 at 6.50.34 PM.png

Since I'm a freshmen I don't currently have the project I'm working on up yet, however I do have work I did at my design high school uploaded, it consists of product design sketches and art work.

https://www.behance.net/williamturner

I'll have my lamp project up by the end of this semester!