After decades in the dark, the long time owners had no idea how to open the case, sunlight fell on not serialised wooden components, partly covered with green velvet.

Its purpose was readily apparent. After a few trials I found the correct position of the crank, the horn elbow and the nickel-plated horn support with taper arm and G&T exhibition sound box.
Elbow and horn support are both secured with a screw, which is screwed in metal thread inserts.

A post, padded with green velvet, fixes the taper arm from above:

After closing of the lid all components are protected against shaking and the now compact size gramophone is much easier to transport.
I suspect that the first owner was an inventive traveller or exhibitor in and around Berlin, where I found the instrument. Do you have something comparable in your collection?