If you ever need to transport a German box clock or a similar style wall clock there are several steps you must take before you remove it from the wall.
One of these procedures is to secure the strike rods. The gong or strike rods are screwed into the gong block. If allowed to move during transport there is a risk that the rod(s) will break. Although they are strong and withstand years of striking they are also brittle and can easily snap. Clock-makers have several solutions for securing the rods. This is one of them. Yours may be similar.
On some clocks, you may find a fork-like device that turns to secure the rods.
By turning it clockwise the three gong rods will fit into the forks as shown in the next photo.
Once the rods are secured in place and you have removed the pendulum rod and bob as well as secure the access door, you can now safely remove your clock from the wall.