JPH0743882Y2 - keyboard - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION This invention reduces the keystroke sound of a keyboard using a membrane switch substrate and the impact felt by a finger.

[0002]

2. Description of the Related Art As a conventional example, a keyboard (actual application 1-31834) before the invention is obtained will be described with reference to FIGS. The housing 1 and the bottom plate 2 attached to it form a keyboard casing, the key tops 3 are mounted on the outer surface of the housing 1, and the membrane switch substrate 4 is sandwiched between the housing 1 and the bottom plate 2.

The bottom plate 2 is made of metal or synthetic resin. The membrane switch substrate 4 is formed by integrally laminating first and second membrane sheets 5 and 6 made of a flexible wiring substrate such as PET (polyethylene, terephthalate) with a spacer 7 interposed therebetween. On the inner surfaces of the first and second membrane sheets 5 and 6, circular switch contacts 8 each made of a conductive film are formed so as to face each other. The spacer 7 is coaxial with the switch contacts 8 and has a switch contact 8
A circular hole 7a larger than the diameter of is formed.

The housing 1 is made of synthetic resin and has contacts 8
Is formed with a circular hole 1a coaxial with the first circular cylinder 1a, and the first and second cylindrical bodies 1b and 1c are respectively formed from the peripheral edge of the circular hole 1a.
It is projected inside and outside. The restoring elastic body 9 is press-fitted onto the outer peripheral surface of the second cylindrical body 1c. Return elastic 9
Is a first cylindrical portion 9a having an inner diameter slightly smaller than the outer diameter of the second cylindrical body 1c and a second cylindrical portion 9b having a larger diameter than that.
And a taper portion 9c connecting them. Each of these parts is arranged coaxially, and the inner peripheral surface of the first cylindrical portion 9a is pressed against the outer peripheral surface of the second cylindrical body 1c.

The key top 3 is made of synthetic resin, and the upper plate 3
a and a tapered portion 3b extending from the peripheral edge of the upper plate 3a
And a cylindrical drive rod 3c projecting substantially in the center of the inner surface of the upper plate 3a facing the housing 1, and a pair extending from the inner surface of the tapered portion 3b in the same direction as the projecting direction of the drive rod 3c. Engaging piece 3d. The drive rod 3c is for pushing the corresponding switch contact portion of the membrane switch substrate 4 by its tip to turn on the switch.
In the key top 3, the drive rod 3c has the restoring elastic body 9 and the first,
It is inserted into the hollow portions of the second cylindrical bodies 1b and 1c. A claw 3e is formed at the tip of the engagement piece 3d, and the claw 3e is engaged with the engagement hole 1d of the housing 1.

On the outer peripheral surface of the first cylindrical body 1b of the housing 1, a plurality of arms 11a are radially formed at substantially equal angular intervals. In the figure, the upper end of the arm is integrally connected to the inner surface of the housing 1. A protrusion 11b protruding toward the membrane switch substrate 4 is formed at the tip of the arm 11a, and the protrusion 11b contacts the membrane switch substrate 4. By these protrusions 11b, the first cylindrical body 1b and the arm 11a are separated from the membrane switch substrate by the protrusion size of the protrusions 11b. Protrusion 1 from the central axis of switch contact 8
The distance R to 1b is set larger than the radius r of the circular hole 7a of the spacer 7. Membrane switch substrate 4 has protrusion 1
It is sandwiched and held by 1b and the bottom plate 2. Protrusion 11
b is the membrane switch substrate 4 outside the circular hole 7a.
Contact with.

When the key top 3 is pushed down against the biasing force of the restoring elastic body 9 with the fingertip, the engagement piece 3d descends in the engagement hole 1d, while the drive rod 3c is made into the first and second cylinders. Body 1b, 1
By moving in c, the tip presses the corresponding contact portion of the membrane switch substrate 4, whereby the first membrane sheet 5 is bent to the opposite second membrane sheet 6 side, and the contacts 8 are closed. . When the fingertip is released from the key top 3, the key top 3 is returned to the position before pressing by the restoring force of the elastic body 9 for return. The first membrane sheet 5 also returns to its initial state by its own elastic force, and the contacts are opened.

[0008]

In the conventional keyboard, when the key top 3 is pushed, the tip of the drive rod 3c pushes the contact portion of the membrane switch substrate 4 to close the contact portion. At that time, the driving rod 3c strikes the bottom plate 2 through the contact portions almost at the same time, which is not desirable because a keying sound is generated and a finger feels a shock. The purpose of this invention is to reduce the keystroke sound of the keyboard and to reduce the impact felt on the finger.

[0009]

According to the present invention, a ring-shaped nodular projection is formed on the inner peripheral surface of the first cylindrical portion 9a of the return elastic body so as to be in contact with the upper end surface of the second cylindrical body 1c of the housing. To be done. On the inner surface of the key top 3, a ring-shaped protrusion
It is formed coaxially with the drive rod 3c so as to face the nodular projection. A coil spring for pressing the contact portion of the membrane switch substrate 4 is inserted into the center hole of the drive rod 3c.
The distance between the nodular protrusion of the restoring elastic body 9 and the ring-shaped protrusion of the key top 3 is set to be smaller than the distance between the tip of the drive rod 3c of the key top and the membrane switch substrate 4.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIG. 1 by assigning the same reference numerals to the portions corresponding to those in FIG. A ring-shaped nodular projection 9d is formed on the inner peripheral surface of the first cylindrical portion 9a of the restoring elastic body so as to be in contact with the upper end surface of the second cylindrical body 1c of the housing. In addition, a ring-shaped projection 3f is formed on the inner surface of the key top 3 coaxially with the drive rod 3c so as to face the nodular projection 9d. The coil spring 11 for pressing the contact portion of the membrane switch substrate 4 is inserted into the center hole of the drive rod 3c.

The coil spring 11 is erected substantially vertically while being placed on the membrane switch substrate 4, and a gap is provided between the upper end of the coil spring 11 and the inner surface of the key top 3. When the key top 3 is pushed down, its gap becomes zero first, and then the coil spring 11 is compressed, and the lower end of the key spring 3 presses the connection portion to close it. Immediately after that, the ring-shaped projection 3f of the key top 3 is the nodal projection 9
Since it comes into contact with d, it is not pressed further. Therefore, the coil spring 11 presses the contact portion more than necessary,
It does not hit the bottom plate 2. Further, the tip of the drive rod 3c is prevented from coming into contact with the membrane switch substrate 4.
That is, the distance d ₁ between the nodular projection 9d and the ring-shaped projection 3f is
Distance between the tip of drive rod 3c and membrane switch substrate 4
It is set smaller than d ₂ .

In the example of FIG. 1, the second cylindrical body 1 of the housing
Although a small-diameter portion 1g having a small outer diameter is provided so as to protrude from the peripheral edge of the upper end surface of c on the side of the drive rod 3c, it may be omitted. The coil spring 11 is mounted on the membrane switch substrate 4, but since it is relatively light, there is no possibility that the contact portion will be closed due to its weight. In FIG. 1, the pair of engagement pieces 3d of the key top 3 are provided so as to face each other, but they may be provided so as to be offset from each other. Accordingly, the engagement hole 1d of the housing 1 is displaced as shown by the dotted line in FIG.

[0013]

According to the present invention, the contact portion of the membrane switch substrate 4 is pressed by the coil spring 11 inserted in the central hole of the drive rod 3c. Even if the key top is pressed, the ring-shaped protrusion 3f causes the nodular protrusion 9d of the elastic body 9 for restoration.
Since it abuts against, it cannot be pressed further. Therefore, the coil spring 11 does not press the contact portion or the bottom plate 2 more than necessary.

Distance between nodal projection 9d and ring-shaped projection 3f
Since d ₁ is set to be smaller than the distance d ₂ between the tip of the coil spring 11 and the membrane switch substrate 4, the tip of the drive rod 3c should be brought into contact with the membrane switch substrate 4 even if the key top 3 is pressed. Therefore, it is possible to prevent the bottom plate 2 from being hit through the contact points. When the key top 3 is pressed, the ring-shaped protrusion 3f comes into contact with the nodal protrusion 9d, but since the nodal protrusion 9d is an elastic body, both the generated sound and the feeling of impact are small.

From the above, the keyboard of the present invention can greatly reduce the keystroke sound and the impact felt on the finger.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a sectional view of the main part of the keyboard before the invention is obtained.

3 is a diagram showing a main part of the housing 1 of FIG. 2, where A is a plan view, B is a front view, and C is a bottom view.

Claims (1)

[Scope of utility model registration request] 1. A housing for a keyboard is constituted by a housing and a bottom plate attached to the housing, a key top is mounted on the outer surface of the housing, and a membrane switch board is sandwiched between the housing and the bottom board. Is formed by integrally laminating first and second membrane sheets with a spacer interposed therebetween, and switch contacts made of a conductive film are formed on the inner surfaces of the first and second membrane sheets so as to face each other. A circular hole coaxial with the switch contact and larger than the diameter of the switch contact is formed in the spacer, the housing is made of synthetic resin, and a circular hole coaxial with the switch contact is formed. First from the periphery,
The second cylindrical body is formed so as to project inside and outside the housing, and the return elastic body is mounted on the outer peripheral surface of the second cylinder body, and the return elastic body is outside the outer peripheral surface of the second cylindrical body. And a second cylindrical portion having a diameter larger than the first cylindrical portion, and a taper portion connecting the first and second cylindrical portions, and the key top is made of synthetic resin. A cylindrical drive rod is formed so as to project from an inner surface facing the housing, and the key top is supported by the return elastic body so that the drive rod can move back and forth in the first and second cylindrical bodies. In the keyboard attached to the housing as described above, a ring-shaped nodular projection is formed on the inner peripheral surface of the first cylindrical portion of the return elastic body so as to be in contact with the upper end surface of the second cylindrical body of the housing. , On the inside of the above key top, A lug-shaped protrusion is formed coaxially with the drive rod so as to face the node-shaped protrusion, and a coil spring for pressing a contact portion of the membrane switch substrate is inserted into a central hole of the drive rod. The distance between the nodular projection of the elastic body for return and the ring-shaped projection of the key top is set to be smaller than the distance between the tip of the drive rod of the key top and the membrane switch substrate. keyboard.