Keyboard device - Patent Review 6056456

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BACKGROUND OF THE INVENTION

The present invention relates to an adjustable volume keyboard device, and more particularly a keyboard device which allows the intervals and height of keys to be changed horizontally or vertically such that the keyboard can expanded or retracted to alter an overall size thereof.

Keyboard devices which allow the intervals and height of keys to be changed horizontally or vertically to effect a change in overall volume are known, but they are not of specified structure which can be readily implemented in practical application.

Accordingly, it is an object of the invention to provide an adjustable volume keyboard which overcomes the drawbacks of the prior art and which is readily adapted to embodiment in a practical keyboard design.

SUMMARY OF THE INVENTION

In accordance with these and other objects of the invention, there is provided a general keyboard device, constituted by a plurality of key switches, each of which is moved in the vertical direction. A return spring is provided between a key top and a contact located below, for entering characters. Switch groups, respectively consisting of several key switches, are arranged in a predetermined direction, and are integrally connected by proper bases respectively. The switch groups are supported slidably to allow extension in the predetermined direction.

The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing the keyboard device in accordance with an embodiment of the invention;

FIG. 2 is a plan view showing a switch group;

FIG. 3 is a side view showing a switch group;

FIG. 4 is a sectional view taken on line A-A of the switch group of FIG. 2;

FIG. 5 is a sectional view showing a structure of a switch;

FIG. 6 is a sectional view showing another structure of a switch;

FIG. 7 is a plan view for illustrating a state in which a pair of adjacent switch groups are maintained in contact with each other;

FIG. 8 is a plan view illustrating a flexible circuit;

FIG. 9 is a simplified plan view showing the outline of the flexible circuit and in which depiction of the details of the circuit has been omitted;

FIG. 10 is a plan view showing the top sheet of the flexible circuit;

FIG. 11 is a plan view showing the bottom sheet of the flexible circuit;

FIG. 12 is a plan view showing one support frame;

FIG. 13 is a plan view showing the other support frame;

FIG. 14 is a sectional view showing a switch for illustrating the vertical movement of a key top;

FIG. 15 is a plan view showing an essential portion for illustrating the relation between adjacent switches; and

FIG. 16 is an illustration showing a leaf spring.

DETAILED DESCRIPTION OF THE INVENTION

The drawings illustrate an example of the keyboard device of the present invention. As shown in the plan view of FIG. 1, in the keyboard device, lengthwise lining groups respectively consisting of several key switches a, a, . . arranged to conform to a standard, are integrally connected in a zigzag pattern to form several switch groups 1, each of a general configuration as shown in FIG. 2.

At both ends of each of these switch groups 1 in the lengthwise direction, support inserts 1a are slidably inserted into guide grooves 2b formed in the inner wall surfaces of support bodies 2a of a keyboard case as shown in FIG. 5. Alternatively, as shown in FIG. 6, extended portions 11a are provided with cylindrical guide holes 12b formed at both ends of each of the switch groups 1 in the lengthwise direction, so that support rods 12a installed in the keyboard case can be inserted through the guide holes 12b to slidably support the switch groups, for allowing extension and retraction in the horizontal direction.

Each of the switch groups 1 has guide protrusions lb extending outwardly therefrom on one lateral side. The guide protrusions lb are inserted into the guide receiving holes 1c formed on the other lateral side of an adjacent switch group 1. Therefore, the adjacent switch groups 1 and 1 are connected with each other to allow stable sliding operation.

Furthermore, each of the switch groups 1 includes hooks 1d formed on one lateral side, to be engaged with the inner wall of the adjacent switch group 1 near the guide receiving holes 1c. These act as a stop for limiting the movement of the respective switch groups 1 and 1.

The keyboard case 2 which supports the respective switch groups 1 is, as shown in FIG. 1, formed to have a size equal to the minimum size of the switch groups 1 after compression achieved by retractive sliding thereof. Furthermore, at both lateral ends of the keyboard case 2, as shown in FIGS. 12 and 13 in detail, support frames 2A which can slide to predetermined positions are installed. The support frames 2A support the outermost switch groups 1 when they are extended to the maximum extent without being disengaged from the keyboard case 2. If several switch groups 1 located at the center of the switch groups 1 are fixed in position, and loaded with springs S in the extension direction, the key switches can be extended at a desired time from the center to the maximum extension positions.

Contacts are provided below the switch groups 1 formed as described above. In accordance with an embodiment of the present invention, as shown in FIGS. 8 and 11, these contacts are installed on a flexible sheet with transformable flexible portions 3a. As shown in FIG. 7, clearances X are formed between the respective switch groups 1, and the flexible portions 3a are bent and housed in the clearances X when the key switches are retracted.

The flexible sheet 3 is itself comprised of a top sheet 3A and a bottom sheet 3B, respectively depicted in FIGS. 10 and 11, each having portions of a printed circuit P disposed thereon, and including opposed contacts which are brought onto selective contact with one another by downward movement of a particular switch a. The top sheet 3A and the bottom sheet 3B overlap one another in the vertical direction, and the respective flexible portions 3a on which corresponding portions of the printed circuit P of each are disposed are horizontally dislocated to avoid mutual overlapping, as shown in FIGS. 10 and 11.

FIGS. 5 and 6 show two different key structures suitably used for the keyboard device of the present invention.

The present invention provides a keyboard device extendible and retractable in a predetermined direction by the above structure or application. In addition to the transformation within a horizontal plane, the present invention also permits the key tops 4 to be changed in height within the vertical planes as shown in FIGS. 14 and 15.

In the illustrated example, the key top 4 is conveniently provided in the form of a cap with a side wall 4a to cover the circumferential surface of a support wall 6 erected from the base, being vertically slidably supported. From about the center in the key top 4, a protrusion 4b is installed downward.

A return spring for maintaining upward biasing of the key top 4 is provided for each switch a in the form of a leaf spring 5. As shown in FIG. 16, leaf spring 5 includes boost tongues 5a bent upwardly from the center toward the tips. When leaf spring 5 is located at a predetermined place on the base, the tips of the boost tongues 5a are kept in contact with the

bottom end of the protrusion 4b of the key top 4, to raise it to the maximum height.

Since the leaf spring 5 is fixed on the base of an adjacent switch group, the boost tongues 5a are moved away from the protrusion 4b, allowing the key top 4 to be moved downward when the switch groups are moved horizontally.

The present invention constituted as described above allows the keyboard device to be changed in volume in horizontal and vertical directions by very simple operation.

Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is riot limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.

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