e the
diaphragm these bars clamp between them a cylindrical piece of iron
_2_, so as to complete the magnetic circuit at the end. At the end
nearest the diaphragm they clamp between them the ends of the soft
iron pole pieces _3-3_, and also a block of composite metal _4_ having
a large circular flange _4'_ which serves as a means for supporting
the magnet structure within the shell. The screws by means of which
the disk _4'_ is clamped to the shouldered seat in the shell do not
enter the shell directly, but rather enter screw-threaded brass blocks
which are moulded into the structure of the shell. It is seen from
this construction that the diaphragm and the pole pieces and the
magnet structure itself are all rigidly secured together through the
medium of the shell at a point as close as possible to the diaphragm.

Between the magnets _1-1_ there is clamped an insulating block _5_, to
which are fastened the terminal plates _6_, one on each side of the
receiver. These terminal plates are thoroughly insulated from the
magnets themselves and from all other metallic parts by means of
sheets of fiber, as indicated by the heavy black lines. On these
plates _6_ are carried the binding posts for the receiver cord
terminals. A long tongue extends from each of the plates _6_ through a
hole in the disk _4'_, into the coil chamber of the receiver, at which
point the terminal of the magnet winding is secured to it. This tongue
is insulated from the disk _4'_, where it passes through it, by means
of insulating bushing, as shown. The other terminal of the magnet
coils is brought out to the other plate _6_ by means of a similar
tongue on the other side.

In order that the receiver terminals proper may not be subjected to
any strain in case the receiver is dropped and its weight caught on
the receiver cord, a strain loop is formed as a continuation of the
braided covering of the receiver cord, and this is tied to the
permanent magnet structure, as shown. By making this strain loop
short, it is obvious that whatever pull the cord receives will not be
taken by the cord conductors leading to the binding posts or by the
binding posts or the cord terminals themselves.

A number of other manufacturers have gone even a step further than
this in securing permanency of adjustment between the receiver
diaphragm and pole pieces. They have done this by not depending at all
on the hard rubber shell as a part of the structure, but by enclosing
the