"[…] 2 is the sound box, 3 the diaphragm, 4 an insulator frame with a trough or depression cut into it and forming an annular groove in which the coil 5 is fixed. This insulator frame 4 is rigidly attached to the diaphragm by means of the bracket support 6 and is held in place on the diaphragm by the screw 7 and lock nut 8. […] Rigidly attached to the pole piece 9 by means of the set screws 10—10 is the spacing ring 11." [US 1448279]
![Abb. 4 aus [US 1448279]](us01448279.gif)