JP3318281B2 - Key switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key switch used for a keyboard or the like which is an input device of a word processor, a personal computer or the like.

[0002]

2. Description of the Related Art Conventionally, as key switches used for this kind of keyboard, there are those disclosed in Japanese Patent Application Laid-Open Nos. 60-60217 and 60-89011. These key switches are provided with a stem protruding downward on the lower surface of the key top and inserted into a key holder portion formed on the holder member to guide and support the key switch so that the stem can move up and down. Rubber spring is arranged. At the lower end of the rubber spring, a switching unit such as a membrane switch having an electric contact formed on a flexible sheet is provided.

In the key switch described in Japanese Patent Application Laid-Open No. 60-60217, when one end of a key top such as a space key having a larger planar shape than a contact portion is pressed, the key top is inclined. It has been proposed to arrange a pair of link members arranged in an X-shape in a side view between the lower surface of the keytop and the holder member so that the link members can be moved up and down in parallel without any trouble. The pair of link members have their substantially central portions rotatably connected to each other.

[0004] In recent years, with the thinning of keyboards, key tops have been flattened, while large keystrokes have been required to improve the operability of key input and ensure the reliability of key input. It is becoming.

However, in the above-described conventional key switch, the key top is moved up and down by a sliding guide between the stem protruding downward from the lower surface of the key top and the key holder. For this reason, in order to reduce the thickness of the keyboard, the vertical dimension in which the stem is slidably guided and supported with respect to the holder must be greatly reduced. Then, when the key is depressed, a kinking phenomenon occurs between the stem and the holder portion, and a problem arises in that smooth and light key operation performance cannot be obtained. If the size of the above-mentioned sliding guide is set large to prevent this, there is a problem that the key stroke becomes short. Therefore,
It has been very difficult to solve the two conflicting problems simultaneously, that is, to reduce the thickness of the keyboard and secure a large key stroke.

In order to solve these problems, the present applicant has proposed the following key switch in the specification and drawings attached to Japanese Patent Application No. 3-330160. First, the vertical movement guide means of the key top is constituted by a first link and a second link which are arranged crosswise in an X-shape in side view, and these two links are rotatably connected at an intermediate crossing portion. Further, one of the free ends of the first link and the second link is slidably locked to the lower surface of the key top and the holder member in a substantially horizontal direction, while one of the free ends of the first link and the second link is locked. The other is rotatably locked to the lower surface of the keytop and the holder member. A cap-shaped elastically deformable rubber spring is disposed below the intersection of the two links. The crossing portion of the guide means elastically deforms the rubber spring by the pressing input operation by the key top, and thereby the switching portion operates as a switch.

[0007]

However, in the key switch having the above-described structure, the first end of the first link is centered on the position of the holder member where the free end of the lower end of the first link is rotatably supported only rotatably. The intersection of the link and the second link draws a trajectory that rotates vertically. However, the shape of the conventional rubber spring has been formed on the premise that the rubber spring is pressed down in a straight line by the stem on the lower surface of the key top. That is, the upper surface of the head of the cap-shaped rubber spring was formed in a horizontal shape.

Therefore, when the upper surface of the head of such a rubber spring is pressed obliquely downward at the intersection of the first link and the second link, the degree of elastic deformation of the dome portion of the rubber spring (the seat of the dome portion). Degree of bending deformation)
There is a large discrepancy between the side closer to the rotation fulcrum of the first link and the side farther from the rotation fulcrum, and the key pressing characteristics vary depending on the key.
For this reason, there is a new problem that the switching operation of the switching portion below the rubber spring also varies.

Further, the position of the rubber spring that covers the switching section also varies due to tolerances.
There is a problem that the switching operation of the switching unit below the rubber spring varies.

Further, since the rubber spring covering the switching portion has a certain thickness in itself,
Further, there is a problem that it becomes an obstacle for making the keyboard thinner.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned various problems, and it is possible to increase the key stroke while responding to the miniaturization and thinning of the keyboard. It is an object of the present invention to provide a low-cost key switch that has good input operability and enables reliable key input.

[0012]

In order to achieve the above object, a key switch according to the present invention comprises a first link and a second link which are arranged to cross each other in a substantially X-shape. and Bei guide member elevating operation guide for supporting the key top and sealed connecting engagement to the support base of the lower Etaki
A switch, which is integrally formed with at least one of the first link and the second link ,
Holds in the non-depressed position is in a raised position, comprising a spring member to increase return the key top has descended is pressed in the non-depressed position, the distal end portion of the spring member
Is the position shifted from the intersection of the first link and the second link
It is arranged in.

[0013]

According to the key switch of the present invention having the above-mentioned structure, the guide member is composed of the first link and the second link which are arranged so as to cross each other in a substantially X-shape, and the lower surface of the key top and its lower surface are formed. The lower support base is connected and locked to guide and support the elevating operation of the key top. The spring member is formed integrally with at least one of the first link and the second link, holds the key top at the non-pressed position, which is the ascending position, and causes the key top that has been pressed down to descend by its elastic force. Return to ascending.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

Referring first to FIGS. 1A and 1B, the configuration of the key switch 1 of the present embodiment will be described. FIG.
(A) removes the key top 2 from the key switch 1 and
FIG. 1 is a top view of a state in which a part of one link is broken, and FIG.
FIG. 2B is a side sectional view of the key switch 1.

The key switch 1 is roughly composed of a key top 2, a guide member 3 detachable from the key top 2, and a support base 50 for supporting the guide member 3.

The key top 2 formed of a synthetic resin such as an ABS resin is provided with characters and symbols such as numerals and letters on the upper surface (surface) by engraving or printing. On the lower surface of the key top 2, the front and rear pins 11 a and 11 b on the upper free end side of the first link 4, which will be described later, are slidably locked in a substantially horizontal direction, that is, in a front and rear direction of the key top 2. A hole-shaped rotation locking portion for locking the rotation shaft portions 13a, 13b of the base portion 22 of the second link 5, which will be described later, so that only the rotation can be performed. 15,1
5 are provided by integral molding.

The guide member 3 includes a first link 4 and a second link 5 connected and arranged in a substantially X-shape in a side view.

Here, referring to FIGS. 3 (a) to 3 (d),
The first link 4 and the second link 5 made of a synthetic resin such as a glass fiber reinforced synthetic resin will be described in detail. FIG. 3 (a)
3 is a plan view of the first link 4, FIG. 3B is a side view of the first link 4, FIG. 3C is a plan view of the second link 5, FIG.
(D) is a side view of the second link 5.

The first link 4 is integrally formed into a substantially H-shape in plan view by a base 18, upper free ends 19a and 19b, and lower free ends 20a and 20b. Support shafts 25a and 25b are protruded. Further, pin portions 12a and 12b are protruded from side surfaces of the lower free ends 20a and 20b, respectively.
Pin portions 11a and 11b protrude from the side surfaces of a and 19b.

The second link 5 has a base 22 and a free end 24.
a and 24b are integrally formed in a substantially U-shape in plan view. Supporting holes 21a and 21b are provided in the side surfaces of the free ends 24a and 24b so as to penetrate in the horizontal direction.
25b is inserted. As a result, the first link 4 and the second link 5 are connected rotatably about the support shafts 25a and 25b. Pin portions 14a, 14b are provided on the side surfaces of the free ends 24a, 24b of the second link 5, respectively, and the base 22 is provided with rotating shafts 13a, 13b.

In this embodiment, the distance from the center line of the support shaft 25a of the first link 4 to the center line of the upper and lower pin portions 11a and 12a, and the rotation from the center line of the support hole 21a of the second link 5 The distances to the center lines of the shaft 13a and the pin 14a are configured to be equal to each other. With this configuration, as described later, the key member 2 is rotated by the guide member 3 centering on the pin portions 12a and 12b at the lower free end of the first link 4, so that the key top 2 is fixed to the holder member 8. It can move up and down while maintaining a state parallel to the upper surface.

The support base 50 includes a holder member 8 made of a synthetic resin for supporting the guide member 3, and the holder member 8.
The flexible printed circuit board 9 is stretched on the lower surface of the holder member 8 so that the switching portion 29 (see FIG. 1A) faces the hole 26 of the above, and the reinforcing plate 10 is stretched on the lower surface side. ing.

The holder member 8 is made of synthetic resin such as glass fiber reinforced synthetic resin (preferably made of a different material from the first link 4 and the second link 5), and has a hole 26 for pressing down. ing. The second spring member 7 formed on the first link 4 can press the switching unit 29 provided on the printed board 9 through the hole 26. On the left and right of the hole 26 of the holder member 8, a pair of left and right rotation locking portions 27 and a left and right longitudinal groove-shaped sliding locking portion 28 are provided.
The lower portions of the locking portions 27 and 28 are integrally injection-molded so as to open. And the two rotation locking portions 27
, The lower end side pin portion 12 of the first link 4
a and 12b are rotatably inserted into the two sliding engagement portions 2
8, the pin portion 14 at the free end of the second link 5
a and 14b are inserted so as to be slidable back and forth.

At this time, the shape of the pin portions 11a and 11b, the pin portions 14a and 14b, and the sliding engagement portions 16 and 28 is such that the first link 4 and the second link 5 are vertically aligned in FIG. And becomes substantially immovable with respect to the
a and 14a are determined so as not to hinder sliding in the left-right direction in FIG. Specifically, in the present embodiment, the base of each pin portion is configured to slide substantially in contact with the inner side surface of the corresponding sliding engagement portion. Therefore, the support shafts 25a and 25b are prevented from falling out of the support holes 21a and 21b.

As shown in FIGS. 1 (a) and 2 (a), the second spring member 7 is disposed above the switching portion (electric contact portion) 29 of the printed circuit board 9 so as to be disposed. It is integrally formed with the base 18 of one link 4.
The second spring member 7 is formed in the shape of a band-shaped leaf spring, and is electrically turned on and then overtraveled (electrically driven).
(Slide after N). Further, the tip 7a of the second spring member 7 is
9 is formed in a shape (for example, an arc shape in this embodiment) in which the switching operation is performed reliably.

As shown in FIGS. 1 to 3, the first spring member 6 is also integrally formed with the base 18 of the first link 4. Further, the first spring member 6 is also formed in a belt-like leaf spring shape, and is configured to be elastically deformed by being bent twice. Therefore, the distance from the end to the end of the first spring member 6 in the bent state is shorter than the distance from the end to the end when the first spring member is extended in a straight line. Further, the distal end portion 6a of the first spring member 6 is configured to always contact the printed board 9, and when the keytop 2 is pressed down, it slides while being in contact with the printed board 9.

At this time, the tip 6 of the first spring member 6
In order to reduce the frictional resistance between a and the printed board 9,
The tip 6a and the printed circuit board 9 are configured to be in line contact or point contact. In this embodiment, the tip 6a has a substantially cylindrical shape. User is key top 2
When keypress 2 is released after pressing
The spring member 6 and the second spring member 7 return to the initial position (the position where the stroke is 0 mm) by the elastic restoring force.

FIG. 4 shows the pressing characteristics of the key switch 1 by the first spring member 6 and the second spring member 7. The pressing force in the section of the pre-travel 17 is determined by the spring characteristics of the first spring member 6, and
The pressing force in the section 3 is determined by the combination of the spring characteristics of the first spring member 6 and the second spring member 7. The pressing force is
It can be changed arbitrarily by changing the material and shape of each spring member. Point A indicates an electrical ON point, and at a position where the stroke is greater than point A, the key switch 1 is always electrically ON. Point B indicates an electrical OFF point, and at a position where the stroke is smaller than point B, the key switch 1 is always electrically OFF. These points can also be arbitrarily changed by changing the shape of each spring member. After the electrical ON point at the point A, the pressing force always changes due to the combination of the spring characteristics of the first spring member 6 and the second spring member 7, so that the user can always recognize that the switch has been electrically turned on as a touch. .

Next, the operation of the key switch 1 of this embodiment will be described with reference to FIGS.

When the user depresses the key top 2 of the key switch 1, the guide member 3 resists the restoring force of the first spring member 6 and causes the guide member 3 to have the pin portion 12a at the lower free end of the first link 4. Rotationally displaces around 12b. At this time,
The tip portion 6a of the first spring member 6 slides while always in contact with the printed board 9, and the key top 2 descends while maintaining a state parallel to the upper surface of the holder member 8.

Then, as shown in FIG. 4, when the stroke reaches the point A via the section of the pre-travel 17 (0 mm to about 2.5 mm), the distal end portion 7a of the second spring member 7
Performs switching operation by contacting the switching unit 29. Further, when the keytop 2 is pressed by the user, the stroke is in the section of the overtravel 23 (approximately 2.
(5 mm to about 4.0 mm), the guide member 3 is configured such that the guide members 3 are opposed to the pin portions 12a, 12
The key top 2 is further rotated and displaced around the center b, and further descends while maintaining a state parallel to the upper surface of the holder member 8.

When the key top 2 reaches the lowest position (the stroke is approximately 4.0 mm), the key top 2 does not descend even if the user presses it further. This state is the state of the key switch 1 shown in FIG.

Finally, when the user releases the key top 2 from being pressed, the key top 2 is released from the first spring member 6 and the second
The key top 2 returns to the initial position (the position where the stroke is 0 mm) by the elastic restoring force of the first spring member 6, first returning to the point B by the elastic restoring force of the spring member 7.

As described in detail above, in the key switch of the present invention, the first link member, the first spring member, and the second spring member are integrally formed. The switching operation can be performed reliably, and the pressing load can be easily adjusted. In addition, since the rubber spring having a certain thickness is eliminated, the key switch can be made thinner, and the number of parts is reduced, so that the assembling time is shortened. Therefore, it is possible to provide a low-cost key switch.

The present invention is not limited to the embodiment described in detail above, and various modifications can be made without departing from the gist of the present invention.

For example, in this embodiment, the first and second spring members are provided one by one on the first link 4, but a plurality of spring members may be provided. In this case, a plurality of switching units may be provided for one key switch, or one switching unit may be used.

Further, the first and second spring members may be provided on the second link 5.

The support base 50 of this embodiment employs a three-layer structure including the holder member 8, the printed circuit board 9, and the reinforcing plate 10, but is a single plate having a certain degree of rigidity. It is also possible to form a single-layer structure in which a holder is formed and a circuit is printed. Further, a multi-layer structure other than three layers may be employed.

When the respective spring members are formed on the base 18 of the first link 4, the material of the base of the link and the material of the spring member may be formed by two-color molding of different kinds of resin materials. However, the present invention can also be realized by inserting or outsert molding the resin material at the base of the link and the metal material of the spring member.

[0041]

As apparent from that described in the foregoing, the key switch of the present invention, either the first link or the second link constitute a draft inner member, to hold the key top in the non-depressed position together, so to form a spring member to increase return the key top was lowered, which is pressed unpressed position integrally with an effect of easy adjustment pressing load, for eliminating the rubber spring with somewhat thick, key Since the switch can be made thinner and the number of parts is reduced, the assembly time is shortened.
An industrially significant effect that a low-cost key switch can be provided is achieved.

[Brief description of the drawings]

FIG. 1A is a top view showing a state in which a key top is removed from a key switch of the present embodiment and a part of two links is broken. (B) is a side sectional view of the key switch taken along the line BB of (a).

FIG. 2A is a top view showing a state in which a key top is removed and a part of two links is broken when a key switch of the embodiment is pressed. (B) is a side sectional view of the key switch taken along the line BB of (a).

FIG. 3A is a top view of a first link. (B) is a side view of the first link. (C) is a top view of the second link. (D) is a side view of the second link.

FIG. 4 is a diagram illustrating a pressing characteristic of a key switch according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Key switch 2 Key top 3 Guide member 4 1st link 5 2nd link 6 1st spring member 7 2nd spring member 29 Switching part 50 Support base part

Claims (1)

(57) [Claims] 1. A key top comprising a first link and a second link which are arranged to cross each other in a substantially X-shape, and which are connected and locked to a lower surface of a key top and a support base portion thereunder. in the key switch example Bei a guide member for guiding and supporting the operation, are integrally formed on at least one of the first link or the second link, and holds the non-pressed position with the key top in the raised position, it is pressed comprising a spring member for raising returning the lowered key top in the non-depressed position, the distal end portion of the spring member, the first link and the second
A key switch which is arranged at a position shifted from a crossing portion with a link .