Eames EA117 (4-Star Base) missing parts?  

Thank you both for your help. I would have liked to hear something else but even that it is a "strange" version is a very useful information to me. I will contact Graham Mancha and will keep you up to date.

Best regards,

jcalca

For the sake of completeness: a picture of the signature on the base

I contacted Graham Mancha this morning and he shared his knowledge and time, so I now know more about my chair and how to get it to life again.

It is not a rare version here in europe and was probably distributed by Herman Miller in the early 70s (but could also be from Mobilier International).

It is missing the collar that holds the shaft into the base and this part can not be delivered as spare anymore. So the only way is to find another base with the same mechanism and get a metalworking company to copy the collar.

Not really what I was hoping for but I am very thankful to Graham Mancha for lifting the fog on this subject!

I will update this if there are any news (but I guess it will take some time...)

Best regards,

jcalca

@jcalca. Ring Mobelfabrikk, also known as Ring Mekannikk,  is just the name of the company that made the mechanism. The company was formed in 1949 . They were based in Moelv, Norway until last year but moved their production to Latvia and the company is still in business making different types of mechanisms for chairs. The company is now known as Ring Chairtech AS

According to a respected member on a Norwegian Forum "Ring mechanics early had an advanced patented torsion bar mechanism delivered to Herman Miller and sat on some of Charles and Ray Eames's early office chairs."(google translated !) No documentation to back this up mind you. Apparently,they also made the base for Arne Jacobsens Egg chair .

@lexi Thanks for these insights. I will just give it a try and contact them, maybe I'm lucky and they can still make the parts.

Excellent detective work! In addition to the missing bushing and/or retention ring, you might ask them about a spare torsion bar as these tend to have only so many cycles in them before they fail, too. Good Luck!

This is what it looks like with the missing part. I never disassembled it, but I guess it's just a ring with the fitting thread inside and holes to turn it.

Should not be too difficult/expensive to manufacture because you can easily measure the thread size and max dimensions.

The "very worn off and probably broken" is not broken, mine looks the same and its just some kind of spacer between the parts.

Don't expect an answer from Ring Mekannik, I sent them a couple of mails 2 years ago to buy a new torsion bar, but never got any reply. But if you're lucky to hear from them, I'm also still interested in an original torsion bar (or at least some information).

Spacer:

@tktoo2 Thanks for your kind words and the tip about the torsion bar! Sadly ringchairtech didn't respond.

@fbndny Thank you very much, I was searching for hours and hours to get a look at this. I'm not sure if the part is just a simple ring with thread because the hole is conical, so I would guess there is a counter-fitting part to it. Since I didn't receive an answer from ringchairtech, I today bought the same base online. It should be here next week and if its not to hard to disassemble I will have a look and make a photo. If I will get a response from the manufacturer I will let you know about the torsion bar.

Keep up the good work!

Best regards,

jcalca

The new (old) base arrived today and it looks very nice. But sadly the tilting mechanism is not working properly. I really have to push hard to tilt back and it comes back forward very slow. Not at all like I'm used to and not comfortable as an office chair.

Is that a sign of a broken/worn torsion bar?

Best regards,

jcalca

@jcalca If the torsion bar had failed there would be no resistance in either direction. The seat would flop forward and back. Sounds like something is binding at the hinge. Maybe lubricate it?

@tktoo2 Thanks for that hint, you were absolutely right, there is a problem with the hinge. Lubrication will not be enough, the hinge is somehow bent and gives extra resistance if tilted. Here is a picture of it.

Not sure yet if I will return the base...

File was too big in the previous post, so here now in reduced quality

@jcalca Yes, there is obvious misalignment there between the inner and outer components. It's possible that certain parts can be bent back into proper alignment but I'd advise close inspection of the welds for any cracks before attempting such. Comparing this tilt mechanism to your original one might offer guidance.