Abstract: An improved keyswitch assembly comprises a housing, a plunger which is spring loaded into a first position, and a channel in the housing through which the plunger can slide from the first position to a second position. A keytop is coupled to the other end of the plunger. The plunger contains a tapered shaft portion. A corresponding frustrum shaped interior portion is provided in the channel which is adapted to mate with the tapered shaft when the plunger is in the first position. This structure eliminates excessive movement of the plunger in a lateral direction within the channel. The tapered shaft portion can be fabricated with a noncircular cross-section in order to prevent rotation of the plunger within the channel. In an alternate embodiment, tapered ribs are provided on the plunger along with corresponding tapered grooves in the channel.

Abstract: In a pushbutton tuner in which a tuning carriage is designed to be laterally positioned by a selected one of a plurality of carriage levers which are designed to slip with respect to the carriage as the carriage is moved, a reduced degree of force is required for moving the carriage by making the levers normally loosely associated with the carriage so that relative motion between them involves little or no friction, but in which the carriage lever operative at any given time to position the carriage is urged into snug engagement with the carriage thereby to eliminate backlash and achieve high accuracy tuning.

Abstract: A communication set tuner has a control member which varies the tuning status of the set; a rotatable input member is provided for driving the control member; the driving connection between the input member and the control member is so designed that the input member may be positioned on the set in any one of a large plurality of available positions. Thus a single driving mechanism structure may be provided which can be used in many different set environments calling for specifically different locations of the input member.

Abstract: A pushbutton tuner of minimal height achieves added tuning accuracy and repeatability and easy assembly adjustment and repair through a novel operating linkage permitting straight-line movement of the operating carriage and biasing of the operative pushbutton key in the direction of movement of that carriage, the linkage being separated into convenient sub-assemblies respectively mounted on the base and cover of the housing.