Parallel guide for push-button switches with multiple buttons

A push-button switch device for keyboards is provided with a multiple keyboard spanning several keys of the keyboard carrier plate and a support arrangement such that operation of the keybutton is balanced even though the key-button switch may be positioned asymmetrically with respect to the multiple button. The support arrangement includes a U-shaped guide bracket which is pivotally fastened on one side in the keybutton and on the other side over the carrier plate. A guide portion is positioned in a carrier plate recess adjacent to the key housing for the push-button switch and has the same shape as the key housing, enabling the guide portion to possibly be replaced by an actual key housing to rearrange the keybutton line-up in the keyboard. The end of the guide bracket adjacent the carrier plate is connected to a support piece which is slidably supported over the upper surface of the guide portion. A guide tongue extends beneath the keybutton through a guide aperture formed in the guide portion. This arrangement serves to align movement of the keybutton during activation of the push-button switch so that jamming of the push-button switch in a multiple button arrangement is prevented.

BACKGROUND OF THE INVENTION 
The invention is directed to a push-button switch structure, particularly 
adapted for utilization in keyboards of typewriters and similar devices, 
and, more particularly, concerns a keybutton arrangement spanning several 
key locations fastened in a keyboard carrier plate. 
German OS No. 2854096 illustrates a known construction for a push-button 
switch for a typewriter keyboard comprising a key housing portion locked 
into a respective recess of a keyboard carrier plate and a keybutton and 
associated striker element positioned for reciprocal movement in the key 
housing. Heretofore, if one wished to arrange a push-button switch with a 
keybutton spanning several key locations, hereinafter referred to as a 
multiple button, then it was customary to arrange the key housing and 
striker centrally of the multiple button. In cases where the multiple 
button was a double button spanning two key locations, the carrier plate 
and associated conductor plate of the keyboard were specially designed for 
the use of two push-button switches to operate simultaneously with a 
unitary, double button. If one attempted to arrange a multiple keyboard in 
such a manner that the associated switch was seated non-symmetrically of 
the multiple button, then the lopsided seating would tend to cause jamming 
of the switch and multiple button due to that portion of the multiple 
button projecting over the push-button switch. 
An object of the present invention is to provide for a push-button switch 
beneath a multiple button without requiring the use of a plurality of 
push-button switches while, at the same time, avoiding a lopsided 
arrangement tending to jam the key button or push-button switch. 
SUMMARY OF THE INVENTION 
A push-button switch is arranged with at least one U-shaped guide bracket 
which fits underneath a keybutton. The bracket is pivotally mounted at 
opposed ends about two rotational axes in such a manner that the first 
axis is defined by hinge pins running longitudinally through the base 
portion of the bracket fastened in a support piece arranged over a carrier 
plate and the second axis is defined by hinge pins running through the 
outer, free ends of the bracket side legs fastened in the keybutton. The 
support piece is seated in a guide portion constructed in the manner of a 
key housing and contains a central opening for receiving a vertically 
extending guide tongue means connected to the key button. The guide 
portion is to be arranged in a carrier plate recess adjacent to the key 
housing for the push-button switch. In this manner, the carrier plate and 
conductor plate of a keyboard need not be specially modified to receive a 
multiple button arrangement. The carrier plate can be fitted with normal 
recesses and later, independently fitted with a varied keybutton line-up, 
including multiple buttons. The present invention makes the manufacture of 
keyboards significantly easier.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1-3 illustrate a teletypewriter keyboard having a conductor plate 1 
in the form of a printed circuit board with appropriate wires arranged 
thereupon and a carrier plate 2 positioned over the conductor plate for 
receivingly suporting individual push-button switches. The carrier plate 
is formed with a series of generally square receiving apertures 3 for 
containing the individual push-button switches which are locked or 
soldered against the conductor plate 1. 
A multiple button 6, shown in the solid line configuration as a double 
button, has a shell housing which is fastened to a key striker or tappet 
element 5 which is positioned in a key housing 4 for a push-button switch 
S. The striker 5 is mounted for reciprocal vertical movement within the 
key housing 4 and is biased by an opposing spring force (not shown) fitted 
in the key housing. The double button 6 is arranged non-symmetrically with 
respect to the key housing 4. 
To prevent jamming of the multiple button during push-button switch 
actuation, a rectangular guide bracket means B is positioned between the 
multiple button 6 and the key housing 4. The bracket means B comprises a 
main portion with a U-shaped profile defined by a longitudinally extending 
base member 7 having a pair of spaced transversely directed legs 8 formed 
at opposed ends thereof and a cooperating auxiliary portion extending 
between the outer ends of legs 8. The guide bracket means is pivotally 
mounted via two rotational axes which run parallel to the longitudinal 
member 7. The first rotational axis is formed by the auxiliary portion, 
which can be a bar-like support piece 9 which is mounted over the carrier 
plate 2. A guide portion 10 having an exterior form similar to that of the 
key housing 4, is positioned within a recess 3 next adjacent to the key 
housing 4. The support piece 9 is slidably disposed over the upper surface 
of the guide portion 10. Opposed outer ends of the support bar 9 are 
formed with hinge pins 11 which cooperate with corresponding pin holes 
formed in the free ends of the transverse legs 8 for pivotal support of 
the guide bracket. The second rotational axis runs through the 
longitudinal member 7. Opposed ends of the longitudinal member are formed 
with further hinge pins 11 cooperatively received in respective guide 
slots 12 formed in the side surfaces of the housing shell of the keybutton 
6 for pivotally supporting the bracket. 
A vertically extending guide tongue means 13 is connected beneath the 
keybutton 6 and extends downward into a generally centrally located, guide 
aperture 14 formed in the guide portion 10. Accordingly, when the 
keybutton 6 is depressed, the striker 5 of the switch S and the guide 
tongue 13 mounted in the guide portion 10 move simultaneously in a 
balanced fashion. The guide bracket B further serves to align the button 
shell housing during its downward movement by cooperation of the bar 9 
with a facing edge surface of the shell to prevent jamming of the button 
and the push-button switch. 
Beveled stop elements 15 are provided on the key housing 4 and guide 
portion 10 to fasten these elements in the apertures 3 of the carrier 
plate 2. 
The inventive arrangement makes possible replacement of the guide portion 
10 with a further key housing for a push-button switch such that the line 
up of the keybuttons may be varied. 
The present invention is not limited to double-type multiple buttons. For 
example, in the case of a triple button, indicated by the dotted line 
configuration shown in the drawings, the guide bracket B is appropriately 
lengthened such that the associated support bar 9 substantially spans 
three receiving apertures 3. By virtue of the guide bracket arrangement, 
jamming of the push-button switch and keybutton 6 is prevented without the 
need for a further guide portion 10 in the third aperture 3. The balanced 
arrangement prevents jamming even when the keybutton 6 is engaged adjacent 
its outer ends. 
Although various minor modifications may be suggested by those versed in 
the art, it should be understood that I wish to embody within the scope of 
the patent warranted hereon all such modifications as reasonably and 
properly come within the scope of my contribution to the art.