Cyclopedia of Telephony & Telegraphy Vol. 1 - A General Reference Work on Telephony, etc. etc. by Robert Millikan;Samuel McMeen;George Patterson;Kempster Miller;Charles Thom
page 176 of 497 (35%)
page 176 of 497 (35%)
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circuits are made and broken are shown at _7_, _8_, _9_, _10_, and
_11_, these being mounted in one group with insulated bushings between them; the entire group is secured by machine screws to a lug projecting horizontally from the bracket _5_. The center spring _9_ is provided with a forked extension which embraces the pin _6_ on the hook lever. It is obvious that an up-and-down motion of the hook lever will move the long spring _9_ in such manner as to cause electrical contact either between it and the two upper springs _7_ and _8_, or between it and the two lower springs _10_ and _11_. The hook is shown in its raised position, which is the position required for talking. When lowered the two springs _7_ and _8_ are disengaged from the long spring _9_ and from each other, and the three springs _9_, _10_, and _11_ are brought into electrical engagement, thus establishing the necessary signaling conditions. [Illustration: Fig. 83. Long Lever Hook Switch] The right-hand ends of the contact springs are shown projecting beyond the insulating supports. This is for the purpose of facilitating making electrical joints between these springs and the various wires which lead from them. These projecting ends are commonly referred to as ears, and are usually provided with holes or notches into which the connecting wire is fastened by soldering. _Western Electric._ Fig. 84 shows the type of hook switch quite extensively employed by the Western Electric Company in wall telephone sets where the space is somewhat limited and a compact arrangement is desired. It will readily be seen that the principle on which this hook switch operates is similar to that employed in Fig. 83, although the mechanical arrangement of the parts differs radically. The hook lever |
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