"The support acts as the main housing of the entire system.It allows the rocking motion of the cradle , holds the wire spring and guides the plungers.The cradle has a cross section which can be considered to be in the form of an irregular 'T' with one end attached to the wire spring , and the other receiving the force from the plunger. Thus when the plunger is pushed down , the plunger end of the cradle moves downward , thus rocking about the fulcrum( support cradle contact ) and stressing the wire spring in bending. At the same time , the base of the 'T' pushes the rubber pushers whichin turn separate the electrical leaf contacts.Thus turning the receiver off.
When the plungers are released , the wire springs , which were stressed release their energy , resulting in rocking back of the cradle, thereby releasing the electrical leaf contacts ( as they are prestresed to remain so , when there are no external disturbances ) and hence turn the receiver on.