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 1 is pivoted at 3 on a bracket 2, which serves to support all the other parts of the switch. The contact springs are shown at 4, 5, and 6, and this latter spring 6 is so designed as to make it serve as an actuating spring for the hook. This is accomplished by having the curved end of this spring press against the lug 7 of the hook and thus tend to raise the hook when it is relieved of the weight of the receiver. The two shorter springs 8 and 9 have no electrical function but merely serve as supports against which the springs 4 and 5 may rest, when the receiver is on the hook, these springs 4 and 5 being given a light normal tension toward the stop springs 8 and 9. It is obvious that in the particular arrangement of the springs in this switch no contacts are closed when the receiver is on the hook.

Fig. 84. Short Lever Hook Switch
[View full size illustration.]

Concerning this latter feature, it will be noted that the particular form of Kellogg hook switch, shown in Fig. 83, makes two contacts and breaks two when it is raised. Similarly the Western Electric Company's makes two contacts but does not break any when raised. From such considerations it is customary to speak of a hook such as that shown in Fig. 83 as having two make and two break contacts, and such a hook as that shown in Fig. 84 as having two make contacts.

It will be seen from either of these switches that the modification of the spring arrangement, so as to make them include a varying number of make-and-break contacts, is a simple matter, and switches of almost any type are readily modified in this respect.

Fig. 85. Removable Lever Hook Switch
[View full size illustration.]