GB1326530A - Push-button key assembly - Google Patents

Abstract

1326530 Substation apparatus INTERNATIONAL STANDARD ELECTRIC CORP 24 Sept 1971 [24 Sept 1970] 44646/71 Heading H4K [Also in Division H1] In a push-button key assembly, key guides project upwardly from a top cover of a housing and each contain means to respond to the depression of the associated key and to displace horizontally a corresponding slider, each slider causing at least one permanent magnet to rotate operating at least one reed contact unit, displacement of any slider also causing a common slider to be displaced, which via a common magnet operates a common changeover switch arrangement. Two arrangements for pushbutton telephone dialling are described. As shown key guides such as 4 project upwardly from the top cover 2 of the housing. Each key guide is integral with the plastics top cover and carries a lever 8 integral with the guide at a point 6 so as to form a hinge. When the associated key is depressed the lever pivots downwardly about the hinge against the action of a spring positioned immediately below the hinge and a nose 9 on the lever displaces a corresponding slider 10 to the right. Lugs such as 21 on the slider engage generally trapezoidal sections of a combination of transverse shafts and cause them to rotate through 90 degrees as shown by the shaft immediately below lug 21. Each shaft carries a permanent magnet which when the shaft is rotated actuates a sealed reed contact unit positioned below the shaft. Any slider when displaced engages the cross-piece 12 of a T- shaped common slider arranged to move in the same direction as the other sliders and coupled to an arcuately movable magnet carrier pivoted about a shaft 17, by means of a spring such that as the point at which the spring is connected to the slider passes the axis of the shaft 17 the arcuately movable member snaps to the position shown moving the magnet it carries from a position adjacent a reed contact unit 16 to a position adjacent a similar unit at the other end of the arc. The common slider is biased towards its original position such that when the depressed key is released the common slider and the slider 10 both return to their original positions. The arcuate member snaps back to its original position before lugs on the common slider turn the transverse magnet carrying shafts to their original positions. The base of the set is closed by a circuit board using printed or punched conductors and extends beyond the housing to allow connection to a cable and the mounting of external components such as diodes.