Push-button switch for a multifrequency dialling telephone set

A push-button switch device for a multifrequency dialling telephone set which is provided with a multifrequency generator having a first terminal connected to a first wire of a telephone line, and with a printed board for the electronic switch parts as a base which is supported on the dial support plate of the telephone set on which the casing of the telephone set is secured, said printed circuit board providing, for each push-button, a pair of contacts and a simple contact of a circuit for selecting a frequency group of said multifrequency generator, said push-button switch comprising:

• first means for connecting said simple contact with said pair of contacts of each said selecting circuit, said connecting means comprising a first rigid conducting horizontal reed pivotably mounted at one end which is tilted on said casing and having a pair of contacts at the other end and a simple contact between said ends, said simple contact and said pair of contacts of said first reed not being in contact with said selection circuit when vertical pressure is exerted on said push-button;
• second means for connecting a second terminal of said multifrequency generator to a second wire of said telephone line, said connecting means comprising second and third rigid conducting right-angle reeds on said circuit board rotably mounted at one of their ends which are respectively connected by windings to said second wire of said telephone line and to said second terminal of said multifrequency generator, the other ends of said second and third reeds being movable and not being in contact when vertical pressure is exerted on said push-button, and a fourth flexible conducting right-angle reed fixed at one of its ends on said circuit board which is connected to said first wire of said telephone line, the other end of said fourth flexible reed being free and being in contact with said movable end of said second rigid reed when pressure is exerted on said push-button;
• and mechanical means comprising first and second springs, the upward stress of said first spring being greater than the downward stress of said second spring and directed against the said downward stress of said second spring and said vertical pressure exerted downwardly on said push-button, and long draw coil springs for releasing said movable ends of said second and third reeds having downward stresses much smaller than said upward stress of said first spring, the downward stroke of said push-button comprising two consecutive phases, namely:
• a first phase during which said pressure exerted on said push-button is directed against the differential force of said stresses of said first and second springs so that said second terminal of said multifrequency generator is disconnected from said second wire of said telephone line and at the end of which said selection circuit of said frequency group is connected to said multifrequency generator for selecting said frequency group;
• and
• a second phase during which said pressure exerted on said push-button is only directed against said upward stress of said first spring, so that after the beginning of said second phase said second terminal of said multifrequency generator is connected to said second wire of said telephone line for transmitting said frequency group to said telephone line.