Fig. A-1. Audograph view showing top surface. The plastic disc mounts on the spindle and is gripped between the two rubber wheels. The rubber wheels are the drive mechanism and are stationary, the needle is mounted just to the right of the wheels on the same assembly. As the disc turns it drives the spindle which is geared to a worm gear underneath. The spindle moves horizontally in its slot, away from the needle.
Fig. A-2. View of the stationary drive wheel and needle assembly.
Fig. A-3. Underneath the top surface showing the worm gear mechanism.