Not sure who made it but IF you think about taking it apart then look through the posts where others have tried !!. It can be done but you could end up with lots of parts and the ball bearing rolling over the floor.....
If you do want to take apart then take lots and lots of pics and make a sketch.
Somewhere on the switch should be a label with the part number on. You might be able to use this to obtain one from these people maybe http://www.technicalarc.co.uk/spare-a-replacement-parts
They have a big catalog inc switches.
And Welcome