Patent of Strida's ball joint

Hi strida forum! :slight_smile: I’m an italian mechanical engineer, I’m making a research about folding bikes!!! I have got a question for you:

Do you know if the Strida’s ball joint is covered by a patent? If the answer is yes, do you know where can I find this patent? I’ve tried to see in this topic Patent documents of Strida but I haven’t found it. Is there a patent not made by strida that reports to the ball joint manufactured by strida?


Mattia :wink:

Hi Mattia,

at Stridaforum!

I’m afraid I don’t understand your quesion fully…who else should refer to Strida’s patents?
As far I understood is that the regarding document:

Best regards,


Sorry, I wasn’t clear in the last comment.

I need of drawings of the spherical joint that you can see at the top vertex of the triangle of the frame.

you can see it here: … CCMQ6AEwAA

You can see the joint in the figure number 6. (You can find it at the sheet 4 of 7, figure 6, element 27 and 28). I’d like to understand how the joint works… And if there are other drawings with more details in other patents, because this one has expired and it’s not so clear the figure 6…

Am I clear now? :slight_smile:

Sorry Mattia - that was completely my fault :blush:

I’ll take a closer look at the drawings - do you think pictures of the part might be helpful?

Principially it’s a relatively simple ball joint connection.
Part 27 and 28 are just a ball on a threaded rod; the rod is connected to the seat tube.
The cup for the ball was created by two symmetrical and separable plastic parts.
These plastic cup halves are held together nowadays just by inserting them into the steering tube; back then - like you see on the Fig. 6 drawing - there was an additional part (6) between the front tube and the cup halves.

Please take also a look here
Ball joint unscrewed
and let me know about your progress :smiley:

Thank you for your help and for the link to the other thread :wink:

Pictures could help me a lot :slight_smile: I think that is a simple joint but I was searching other validation. :slight_smile:

An other question: Is there a “standard” head-set in the Strida?? Or the head-set is partially substituted from the work of ball joint?

Thanks :smiley:

I’m here to help… :smiley:

For the headset:
Let’s say a common headset are two ball bearings - ok?
On a Strida there are also two, but downstairs around part nr. 216, the locking mechanism.
One could see the ball joint as an additional “bearing” which is supporting the ball-bearings 100-03 and 100-04.
Hope you’ve got the part nr. drawings handy…if not look at page 14 of the

What kind of pics do you want?
The inside of the thingy?


you could also have a look at Mark Sanders’ master thesis that lead to the serial development of the Strida:

The ball joint design might however have changed since then (1985!).