Keyboard allowing for simple, cost-effective production

FIELD OF THE INVENTION

The present invention relates to computer systems and other devices having keyboards and more particularly to keyboards. Even more particularly, the present invention relates to a simpler and more cost-effective way of designing and producing the keys on such keyboards.

BACKGROUND OF THE INVENTION

As is well-known, in various devices including personal computers (PC) and electronic desk calculators, a keyboard to be operated by a user is constructed so that each of a plurality of keys is capable of movement through an upstroke/downstroke (hereinafter referred to as “up/down movement” in this specification). The functions required of such keys include, in addition to a function of allowing the key top to move up and down, a function of operating a switch provided on a circuit board at a position below each key, and a function of returning the key top to the home position after allowing the key top to be depressed, and also include, as a function for enabling a user to feel improved key response when operating the key, a function of stopping the key from shifting in any direction other than the vertical direction when the key top moves up and down.

FIG. 6

shows an example of a known structure of a key having such functions. In

FIG. 6

are illustrated a key top

1

forming a key face, reference numeral

2

denotes an up/down mechanism which supports the key top

1

so that the key top

1

can move up and down, and reference numeral

3

denotes a rubber dome for returning the key top to the home position.

The up/down mechanism

2

is constituted by a pair of arms

4

and

5

, a top plate

6

, and a fixing member

7

. In this up/down mechanism

2

, the arms

4

and

5

are rotatably connected to each other by a shaft

4

a

so as to operate as a pantograph or scissor, thereby enabling movement in the up/down direction. The top plate

6

is rotatably connected at its one end to the arm

4

and slidably engages with the arm

5

at the other. The top plate

6

has a function of operating as an element for reinforcing the arms

4

and

5

when the arms

4

and

5

expand or contract, and a function of receiving the top end of the rubber dome

3

. The fixing member

7

slidably fixes the lower ends of the arms

4

and

5

on an unillustrated base plate.

The rubber dome

3

is made of an elastic material, which is a kind of rubber or the like. The rubber dome

3

is placed inside the up/down mechanism

2

and its top end is brought into abutment against the lower surface of the top plate

6

of the up/down mechanism

2

. A downwardly-projecting projection is provided on the reverse side of the top end of the rubber dome

3

to operate a switch in a membrane sheet (circuit board) provided on the unillustrated base plate.

In the thus-constructed key, when a user depresses the key top

1

, the up/down mechanism

2

operates so as to contract. The rubber dome

3

is thereby compressed and deformed to move its top end downward. With the downward movement of the top end, the unillustrated projection provided on the reverse side of the top end presses the switch, thereby enabling the key top

1

operation to be detected.

The compressed and deformed rubber dome

3

has a force for restoring its original shape. When the user stops pressing the key top

1

downward, the top plate

6

is moved upward by the restoring force of the rubber dome

3

to expand the up/down mechanism

2

, thereby returning the key top

1

to the home position.

There are problems associated with a key having the above-described construction in that the structure of the up/down mechanism

2

is particularly complicated and the parts cost and assembly cost are therefore high. As is well-known, a keyboard has a plurality of keys, assembly of the parts of each key is time-consuming, and the total number of parts is considerably large. Therefore it is important to solve the above-described problem.

The number of parts of the up/down mechanism

2

may, of course, be reduced in any number of ways. From the viewpoint of maintaining the desired stability of the key during up/down movement, however, it must be said that it is difficult to reduce the number of parts without sacrificing other desirable characteristics of the key—such as stability, feel, consistency, etc. Therefor, it is an object of the present invention to provide kays on a keyboard which provide a user with the desired feel and stability of current keyboards but which may be produced using fewer parts and at a lower cost.

SUMMARY OF THE INVENTION

The inventors of the present invention have studied eagerly with this object and found it effective to form a plurality of keys as one integral component. However, problems described below arise in a case where a plurality of keys are formed as one integral component.

As shown in FIG.

5

(

a

), in a case where keys are formed by combining a key member

11

and a cover

12

, a plurality of (e.g., two) key tops

11

a

formed on the key member

11

so as to project upward therefrom are fitted in holes

12

a

formed in the cover

12

.

Ordinarily, the above-described key member

11

and cover

12

are provided as molded resin components. Any combination of a plurality of components, including such molded resin components, entails a problem relating to a working error.

A predetermined tolerance is given on each of the distance P

1

between key tops

11

a

and the distance P

2

between the holes

12

a

determined at the time of resin molding. For example, in a case where a row of a plurality of keys is formed such that each of the distances P

1

and P

2

between the keys placed at the opposite ends exceeds 100 mm, a tolerance of typically ±0.25 mm exists. In this case, if the distance P

1

of the resin molded key member

11

includes a working error of −0.25 mm and if the distance P

2

of the cover

12

includes a working error of +0.25 mm, a total error of 0.50 mm exists between the two distances.

Then, when the key top

11

a

of the key member

11

is fitted around the hole

12

a

of the cover

12

shown in FIG.

5

(

b

), the center of the key top

11

a

is out of alignment with the center of the hole

12

a

, even though each of the key member

11

and the cover

12

has the accuracy within the tolerance.

If such a misalignment exists, interference may occur between the key top

11

a

and the hole

12

a

to impede the up/down movement of the key top

11

a

. To avoid this interference, a clearance is set between the outside diameter of the key top

11

a

and the inside diameter of the hole

12

a

by factoring in an error within the above-described tolerance.

However, a state where the amount of misalignment of the key top

11

a

with the hole

12

a

in one direction is so large that a portion of the gap

13

around the key cap

11

a

narrows or disappears, as shown in FIG.

5

(

b

), is undesirable in terms of appearance. For this reason, the clearance may be increased to ensure that the gap

13

is continuously formed along the entire perimeter of the key top

11

a

. From the keys with an increased clearance, however, a user may have the impression that the working accuracy of the entire PC is low. Also, the possibility of foreign objects or the like entering through the gap

13

is increased.

The above-described problems become more serious if the number of keys continuously arranged to form one integral component is increased or if the length of the integral component is increased.

The above-described problems can of course be solved if the working error at the time of molding of each of the key member

11

and the cover

12

is reduced. However, this is not an effective solution of the problems since use of means for reducing the working error of the molded resin components leads directly to a considerable increase in mold cost.

A computer system in accordance with the present invention provided by considering the above-described problems has a keyboard of a construction in which a plurality of keys arranged in a continuous row at least in one direction are supported on a frame having an adjustment portion for enabling adjustment of the position of each of the plurality of keys in the above-mentioned direction. Preferably, the plurality of keys are integrally supported on the frame.

The adjustment portion may be of any construction if it enables adjustment of the position of each of the keys supported on the frame. A deformable portion which is a portion of the frame deformable in the lengthwise direction of the frame may be provided as the adjustment portion. The frame is deformed in the lengthwise direction to adjust the pitch (interval) of the keys supported on the frame. Thus, in the structure in which the plurality of keys are supported on the frame, the position of each key can be adjusted to absorb working errors of the components.

An arrangement is conceivable in which an up/down mechanism, e.g., the mechanism

2

shown in

FIG. 6

is used as a mechanism for enabling keys to move up and down and is supported on a frame. However, from the viewpoint of the object of reducing the number of parts by integrally combining a plurality of parts in accordance with the present invention, it is preferred that the frame itself have a mechanism for enabling the keys to move up and down. That is, elastically deformable arms extending from the frame are formed and the keys are provided on the arms. In this case, the keys may be formed integrally with the arms or may be provided as separate parts to be attached to the arms.

If a cover member which can close space between the plurality of keys are provided on the keyboard, it is preferable to form positioning portions such as pins for positioning the keys supported on the frame. The frame on which the keys are supported is corrected by the positioning portions to adjust the positions of the keys.

The present invention can also be grasped as a device not limited to the computer system. This device is characterized by including a plurality of keys, a frame extending in a direction corresponding to the direction of arrangement of the plurality of keys in a continuous row, and arms extending from the frame and capable of enabling the plurality of keys to move up and down. In the device thus constructed, the number of parts constituting the keys can be limited to the smallest possible number.

The frame is provided on both sides of the continuous row of the plurality of keys arranged in one direction. Curved/bent portions curved or bent laterally may be provided on the frame. The curved/bent portions are provided for adjustment of the pitch of the plurality of keys.

The present invention can also be grasped as a keyboard having a plurality of keys. This keyboard is characterized by including a frame provided with adjustment portions for adjusting the spacing between the plurality of keys and positioning portions for positioning the keys on a base of the keyboard.

This keyboard may also have a cover member which closes space between the plurality of keys. Preferably, positioning pins for positioning the positioning portions on the base are provided on the cover member. While the spacing between the keys is adjusted by the adjustment portion, the keys are positioned and fixed by the positioning portions. It may otherwise be said that the keys are positioned on the cover member, but the positioning in this expression is essentially the same as positioning of the positioning portions on the base since both the keys and cover member are mounted on the base.

In this case, the plurality of keys are not always arranged in a continuous row in one direction. For example, the present invention may be applied to an arrangement in which keys are alternately placed on opposite sides of a line, i.e., a staggered key layout.

A keyboard in another aspect of the present invention has a frame on which a plurality of keys arranged in one direction are supported so as to be able to move up and down, and which is provided with a deformable portion capable of deforming along the direction of arrangement of the plurality of keys and holes provided on opposite sides of the deformable portion. This keyboard also has a cover having openings through which the plurality of keys are exposed, the cover also having pins which are passed through the holes of the frame to be fixed on a base. If the frame and the cover have variations in size due to working errors or temperatures, the frame is fixed while absorbing the errors in such a manner that the pins of the cover are passed through the holes provided on the opposite sides of the deformable portion of the frame and are fixed on the base.

A key member constituting the keyboard of the present invention is characterized by including a pair of side support portions, a plurality of key tops placed between the pair of side support portions, and arms each having its one end connected to one of the key tops and the other end connected to one of the side support portions, each arm being elastically deformable. In this arrangement, when one of the key tops is pressed, the arms are elastically deformed to realize stroke movement of the key.

If a curved/bent portion is formed on each side support portion between each adjacent pair of said key top, the pitch of the keys can be adjusted.

Preferably, the arms extend from the corresponding one of the key tops toward the pair of side support portions so as to have a shape similar to the shape of the letter V, and the next key top is located between these arms extending generally in the form of V. In this manner, the length of the arms is maximized.

In other words, the other ends of the arms are connected to the side support portions in the vicinity of the next key top adjacent to the key top to which the one ends of the arms are connected.

This arrangement, in which each pair of arms are respectively joined to the side frames on opposite sides of the row of the plurality of keys, is not exclusively used. For example, another arrangement is possible in which a pair of arms extending from each key top are joined only to one of the frames located on opposite sides of the row of the plurality of keys.

Preferably, each of the above-described arms is formed so that its sectional area is smaller at the other end on the side support portion side than at the one end, whereby deformation of the arm when the key top is pressed for a key operation is concentrated in a portion closer to the other end. In contrast, in an arm without such a change in sectional area, deformation of the arm is generally uniform through the entire length of the arm. In comparison between these types of arms, while the inclination of the key top surface on the one end of the arm without a change in sectional area is large, the inclination of the key top surface can be reduced in the case of the above-described arm in which deformation is concentrated at a position closer to the other end.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereafter, the present invention will be described in detail in accordance with the embodiment(s) shown in the accompanying drawings, in which:

FIG. 1

is a diagram showing an example of a PC having a keyboard in an embodiment of the present invention;

FIG. 2

is a perspective view of a cover member and a key member;

FIG. 3

comprises a plan view and a side view of the key member;

FIG. 4

is a diagram showing deformation of the key member when the hey is operated;

FIG. 5

shows a problem in a case where a plurality of keys are arranged in a continuous row, and comprises a diagram (a) showing the relationship between the cover member and the key member, and a diagram (b) showing a state in which the key is placed one-sidedly; and

FIG. 6

is a diagram showing an example of a conventional key structure.

DETAILED DESCRIPTION OF THE INVENTION

Referring to

FIG. 1

, the PC

20

provided as a computer system device is of a notebook type and has a monitor portion (display section)

21

for displaying images, and a main body portion

22

incorporating a mother board, a HDD, etc. The mother board is provided as a control unit which controls display contents on the monitor portion

21

. The monitor portion and the main body portion are open/closably connected to each other.

A keyboard

24

on which a certain number of keys

23

are arranged in a certain layout is provided in an upper surface of the main body portion

22

.

In this embodiment, the present invention is applied to some of keys

23

provided on the keyboard

24

, e.g., a function key block

25

which is provided in a left-hand portion of the keyboard

24

, and in which a certain number of (e.g., six) keys

23

are arranged in a continuous row in one direction.

As shown in

FIG. 2

, the function key block

25

is constituted by a key member

30

and a cover member

40

.

As shown in

FIGS. 2 and 3

, the key member

30

, which is made of a resin, has a frame

31

whose entire shape is generally rectangular, pairs of arms

32

extending inwardly from the frame

31

, and key top portions (key tops)

33

formed integrally with ends of the arms

32

and constituting keys

23

. The frame

31

, the arms

32

, and the key top portions

33

are formed integrally with each other. In this embodiment, six key top portions

33

, for example, are arranged in a continuous row in one direction to form the key member

30

.

The frame

31

is formed by a pair of side support portions

34

and end joint portions

35

so as to have a generally rectangular shape as a whole. The side support portions

34

are positioned on opposite sides of the row of the key top portions

33

and extend along the same. The pair of side support portions

34

are connected at their opposite ends by the end joint portions

35

.

In the side support portions

34

, curved portions (adjustment portions, shaped portions, curved/bent portions)

36

each bent into a shape similar to the shape of the letter U are formed at a plurality of positions along the lengthwise direction of the side support portions

34

. The curved portions

36

is elastically deformable in the lengthwise direction of the side support portions

34

, i.e., in such a direction that the generally U-shaped opening narrows or expands, thereby enabling the side support portions

34

to expand or contract. In this embodiment, curved portions

36

are formed at predetermined positions corresponding to the key top portions

33

.

On each side support portions

34

, projections

34

a

are formed at a plurality of positions along the lengthwise direction of the side support portion

34

so as to project inwardly inside the frame

31

. In each projection

34

a

, a hole (positioning portion)

37

is formed which functions as a positioning hole when the frame

31

is combined with the cover member

40

, as described below. Each hole

37

provided in the side support portion

34

is formed at least in front or at the rear of one of the curved portions

36

as seen in the direction of continuous arrangement of the plurality of key top portions

33

. In this embodiment, a number of holes

37

corresponding respectively to the key top portions

33

are provided in each side support portion

34

at predetermined positions, e.g., in the vicinities of the curved portions

36

. Also, a projection

35

a

in which holes

37

are also formed is formed on each end joint portion

35

.

As shown in FIG.

3

(

a

), the pairs of arms

32

extending from the two side support portions

34

have their extreme end portions

32

a

formed integrally with the key top portions

33

. That is, each key top portion

33

is supported on the frame

31

by the pair of arms

32

.

The arms

32

respectively meet the side support portions

34

so that a predetermined angle is formed between each arm

32

and the corresponding side support portion

34

. In other words, each pair of arms

32

extend from the key top portion

33

so as to have a shape similar to the shape of the letter V such that the distance therebetween is gradually increased, and their base ends

32

b

meet the side support portions

34

at positions in the vicinity of and on opposite sides of the next key top portion

33

. The next key top portion

33

is positioned between the pair of arms

32

extending generally in the form of the letter V.

At a position where each pair of arms

32

meet each other at their extreme end portions

32

a

in the vicinity of the key top portion

33

, a reinforcing portion

38

in the form of a plate is formed between the pair of arms

32

. Each arm

32

is formed by being tapered from the extreme end portion

32

a

toward the base end portion

32

b.

As shown in

FIG. 4

, each pair of arms

32

thus formed are elastically deformed to allow the corresponding key top portion

33

to be displaced when the key top portion

33

is pressed in a direction perpendicular to a plane defined along a major side of the frame

31

(in the direction of arrow (

1

) in the figure). At this time, since the pair of arms

32

are smaller in sectional area on the base end

32

b

side and are connected to the reinforcing portion

38

on the extreme end side

32

a

, deformation of the arms

32

is concentrated on portions closer to the base ends

32

b.

For example, each key top portion

33

has a generally dome-like shape generally circular as seen in a plan view and opened at its lower end

33

a

. A section of each key top portion

33

closer to a face surface

33

b

of the same touched by a user when the user operates the key

23

is formed so as to project away from the plane defined by the arms

32

and the frame

31

on one side of the plane. Since the frame

31

and the arms

32

are formed so as to be uniform in thickness, only the key top portions

33

protrude from the key member

30

on one side.

An extreme end portion of an unillustrated rubber dome is brought into abutment against the backside surface of the face surface

33

b

of the key top portion

33

. This rubber dome is made of an elastic material, which is a kind of rubber or the like, as is the rubber dome

3

shown in

FIG. 6

as a component in the conventional arrangement. The rubber dome has the function of operating a switch in a membrane sheet provided on an unillustrated base plate when the key top portion

33

is depressed, and the function of returning the depressed key top portion

33

to the home position.

A flange

39

is formed integrally with each key top portion

33

so as to extend outwardly from the lower end

33

a

. The outside diameter of the flange

39

is set to a value approximately equal to the inside diameter of an opening

42

of the cover member

40

described below. The flange

39

is intended for visually closing the gap between the key top portion

33

and the edge of the opening

42

. As shown in FIG.

3

(

a

), a stopper

39

projecting beyond a line defined by the inside diameter of the opening

42

is formed in a plurality of places, e.g., two places on the periphery of the flange

39

, thereby preventing the key top portion

33

from coming off the cover member

40

through the opening

42

.

As shown in

FIG. 2

, the cover member

40

is a resin member having a covering portion

41

which, in a state of being mounted on the keyboard

24

, forms a surface of the function key block

25

while closing the gap between each adjacent pair of key

23

, and in which a certain number of openings

42

(six openings

42

in this embodiment) into which the keys

23

are to be fitted are formed.

The inside diameter of the openings

42

is set to a value larger than the outside diameter of the above-described key top portions

33

of the key member

30

and smaller than the outside diameter of the stopper

39

a

of the flange

39

.

Positioning pins (positioning portions, pins)

43

A and

43

B for positioning in combination with the key member

30

are formed so as to project from the reverse surface of the covering portion

41

. The lengths of the positioning pins

43

A and

43

B are set to different values. The shorter positioning pins

43

A have only the function of positioning the key member

30

, while the longer positioning pins

43

B have, in addition to the key member

30

positioning function, the function of fixing the cover member

40

and the key member

30

on the unillustrated base member. That is, the longer positioning pins

43

B pass through the holes

37

of the key member

30

, project from the reverse side of the key member

30

, and are inserted into holes formed in the base plate (not shown) on which the predetermined number of keys

23

are supported. Extreme end portions of the positioning pins

43

B projecting from the reverse side of base plate (not shown) are hot welded to fix the key member

30

and the cover member

40

on the base plate (not shown).

In assembly of the function key block

25

having the above-described construction, the positioning pins

43

A and

43

B of the cover member

40

are inserted into the holes

37

of the key member

30

. At this time, even if the cover member

40

and the key member

30

have working errors, the curved portions

36

provided in a plurality of places in the side support portions

34

of the key member

30

function so as to present any undesirable result from these errors in such a manner that the positioning pins

43

A and

43

B of the cover member

40

, when inserted into the holes

37

, correct the positions of the key top portions

33

by deforming the curved portions

36

so that the curved portions

36

expand or contract in length. Thus, even if the cover member

40

and the key member

30

have working errors, occurrence of misalignment between the openings

42

of the cover member

40

and the key top portions

33

of the key member

30

can be prevented to prevent impairment of the appearance. As described above, the function key blocks

25

in which a plurality of keys

23

are arranged in a continuous row can be formed only of the key member

30

and the cover member

40

to remarkably reduce the number of parts in comparison with the conventional complicated structure, thus reducing the parts cost and the assembly cost.

Also, the above-described construction makes it possible to absorb variations in size of the cover member

40

and the key member

30

due to working errors or temperatures by deforming the curved portions

36

. Therefore it is possible to reduce the accuracy of working of the cover member

40

and the key member

30

in comparison with the conventional art. A cost reduction effect thereby achieved is also large.

Moreover, the key member

30

is arranged to have the arms

32

elastically deformed for up/down movement of the keys

23

without using a complicated structure such as the conventional up/down mechanism

2

. Thus, up/down movement of the keys

23

is realized by using a markedly simple structure. Also, the arms

32

are formed so as to extend from one key top portion

33

to points on opposite sides of the next key top portion

33

so as to have a shape similar to the shape of the letter V. In this manner, the length of the arms

32

is maximized. If the arms

32

are longer, the line along which the key top portion

33

is moved up and down can be brought closer to a vertical line to ensure that a user can feel a natural key response in operating the key without being conscious of the inclination of the key top portion

33

. Moreover, the generally V-shaped arms

32

enable the key top portion

33

to move up and down with stability such as not to have a roll, etc., in unnecessary directions.

The arms

32

are formed so that their sectional area is smaller at their base ends

32

b

remote from the key top portion

33

. Therefore, elastic deformation of each arm

32

caused when the key top portion

33

is operated is concentrated in a portion closer to the base end

32

b

. If the arm

32

is designed so as to be uniform in sectional area, the entire arm

32

is bent so as to have a radius of curvature generally constant through its entire length. In contrast with this, deformation of the arms

32

in the above-described arrangement is concentrated in a portion closer to the base end

32

b

to reduce the inclination of the extreme end

32

a

of the arm

32

, i.e., the key top portion

33

. As a result, a user can feel improved key response without being conscious of turning of the key top portion

33

about the base ends

32

b

of the arms

32

when operating the key.

While curved portions

36

formed into a shape similar to the shape of the letter U have been described by way of example in the description of the embodiment, it is needless to say that the curved portions

36

may have any other shape, e.g., a shape similar to the shape of the letter V without any problem. Also, needless to say, any other structure allowing expansion/contraction of the key member

30

may be used.

The embodiment has been described with respect to an arrangement in which the curved portions

36

and the holes

37

(and the corresponding positioning pins

43

A and

43

B on the cover member

40

side) are provided in correspondence with the key top portions

33

. This arrangement, however, is not exclusively be used. These components may be provided at intervals selected as desired.

While in the above-described embodiment each arm

32

is reduced in sectional area on the base end

32

b

side to concentrate deformation on a place closer to the base end

32

b

, a slit or the like formed in a place closer to the base end

32

b

may alternatively be used if the same function can be achieved.

Further, while in the above-described embodiment the positioning pins

43

A and

43

B are provided on the cover member

40

, the arrangement may alternatively be such that positioning pins are provided on the base plate on which the function key block

25

is supported and the key member

30

, and the cover member

40

are positioned on these positioning pins.

The function key block

25

in which six keys

23

, for example, are arranged in a continuous row in one direction has been described by way of example in the description of the embodiment. However, any other key layout, e.g., an array of keys forming a plurality of rows and a plurality of columns in two directions (row and column directions) perpendicular to each other may be provided, the keys being formed by an integral member corresponding to the above-described key member

30

. In such a case, portions having the size adjustment function like the above-described curved portions

36

in at least one direction (along columns or rows) are provided. More preferably similar portions for adjustment in the other direction (along rows or columns) are also provided.

A row of keys

23

constructed by attaching the cover member

40

to the key member

30

has also been described by way of example in the description of the embodiment. However, the arrangement may alternatively be such that key top members of the same type as the key top

1

shown in

FIG. 6

are fitted on the key top portions

33

to form keys. In this case, the key top portions supported on the arms

32

function as a mechanism for enabling up/down movement of the key top members.

Deformation of the curved portions

36

can also be used effectively not only as the size adjustment function for absorbing working errors or the like but also as a deformation absorbing function in a case where a plurality of keys are placed along a curved surface.

The above-described key structure can be applied not only to the keyboard

24

of the PC

20

but also to keys and switches for use in various devices such as electronic desk calculators and vending machines.

The examples of the arrangement described above with respect the embodiment of the present invention may be selected or replaced with other arrangements as desired within the scope of the invention.