Solid Walnut Arm Chairs - looking for info on Manufacturer

I bought these used / vintage about 8 years ago. There is no label on them. I have not seen anything like them and am wondering if anyone knows possible make or manufacturer? I've seen somewhat similar arm structure on Helikon arm chairs?

They are solid walnut and appear to be very well made. I'm thinking late 70's.

Thanks in advance for any information.