JPH0439615Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a push button switch used in keyboards of electronic devices, etc., and in particular, a push button switch with a function that allows the operator to feel the opening and closing of the switch contacts. This is related to the improvement of.

<Prior art> A push button switch that opens and closes an electrical contact consisting of a fixed contact provided on a circuit board and a movable contact that is activated by operating a key top, and has a function that allows the operator to feel the opening and closing of the switch contact. As a push button switch with
The one disclosed in Publication No. 81719 is known.

The mechanism will be explained below based on FIGS. 14 to 16.

In the figure, reference numeral 114 denotes a substrate, and a frame 112 having a cylindrical support 111 is attached to the substrate 114. 110 is the cylindrical support 1 of the frame 112
The key top is slidably mounted along the cylindrical support 111 and has a downwardly extending mandrel 116 inserted into the cylindrical support 111. The tip of the mandrel 116 is a bifurcated skirt portion 117, and a stop portion 126 provided on the outer surface of the tip of the skirt portion 117 engages with a shoulder portion 127 on the inner surface of the cylindrical support 111. , thereby restricting upward movement of the key top 110. 115 is a thin film contact switch provided on the substrate 114;
A pivot type actuator 119 is fixed on the upper surface thereof, and is configured to close the contact switch 120 of the thin film contact switch 115 when the key top 110 is pressed.

A spring 118 is interposed between the strut 123 of the actuator 119 and a mounting seat 121 provided on the shaft 116 of the key top 110, with the spring 118 slightly bent in a selected direction. Directional bending is limited by the skirt 117 of the mandrel 116.

The actuator 119 also has a support base 122 whose tip constitutes a pivot axis during initial rotation, and a protrusion 124 extending downward and having a curved bottom. When not connected, a small distance is maintained between the top surface of the contact switch 120 and the top surface of the contact switch 120.

In the push button switch as described above, when the key top 110 is pushed from the position shown in FIG. 14 to the position shown in FIG. 15, the force transmitted to the actuator 119 by the spring 118 increases. FIG. 16 shows the relationship between the force applied to the key top 110 while pressing the key top 110 and the amount of movement of the key top 110.

By pressing the key top 110, a force greater than the force acting at rest is applied to the actuator 119, and a moment generated by the bending of the spring 118 tends to rotate the actuator 119 clockwise. , is larger than the moment that acts to rotate the actuator 119 counterclockwise at the rest position, so the actuator 119 rotates clockwise using the tip of the support base 122 as a pivot axis. Due to this rotation, the protrusion 1
The bottom surface of 24 touches the top surface of the contact switch 120,
As shown in FIG. 15, the contact switch 120 of the thin film contact switch 115 is closed. Point 131 in Figure 16
indicates the position of the key top in this case. When the contact switch 120 closes, the spring 118 flexes excessively as shown in FIG. 15, causing the operator to feel this and remove his finger from the key top 110. When the key top 110 is released, the actuator 119 continues to rotate clockwise and the contact switch 120 is initially Although it is in the closed state, the spring 118 immediately tries to return to its original state, so the moment decreases. 1st
A point 132 in FIG. 6 indicates the position of the key top in this case, and eventually the moment for turning the actuator 119 counterclockwise becomes larger than the above moment, and the actuator 119 starts turning counterclockwise and returns to the rest position. Also, point 1 in Figure 16
33 shows the position state of the key top when the key top 110 returns to the initial position and the actuator 119 is in the position shown in FIG.
Point 130, which indicates the position of the key top when no key is pressed, has a movement amount of 0 due to loss due to friction during movement, but there is a slight difference in force.

As can be seen from Fig. 16, the physical hysteresis that appears with key operations indicates that there is a sensitivity to the opening and closing of the contact switch, and this allows the operator to sense the opening and closing of the contact switch. be able to. That is, when the contact switch is opened or closed, the key top 110 always moves a little so that the operator can feel the movement.

<Problems to be solved by the invention> However, in the conventional push-button switch described above, it is necessary to provide an actuator with a complicated shape in order to convey the feeling of opening and closing the contact switch to the operator. Assembly is also complicated, as the parts must be assembled from two directions rather than from the same direction. Also, since the spring and actuator always come into contact at the same place,
Contact parts are worn out. As a result, the opening/closing sensitivity becomes dull, and the opening/closing accuracy and mechanical life of the switch are reduced. Furthermore, if even one of the actuators is defective, it cannot be replaced without removing the board, which poses the problem of requiring a great deal of effort and man-hours to repair.

The purpose of the present invention is to solve these problems and provide a push button switch that provides a rich feel when opening and closing, is highly reliable, and has a long life.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the push button switch of the present invention opens and closes electrical contacts consisting of a fixed contact provided on a board and a movable contact activated by key operation. A push button switch has a key housing with a spring seat cylindrical body erected at the center of the bottom surface,
A key top is fitted into the spring seat cylindrical body of the key housing and is slidable while being regulated by a stopper, and a large diameter end turn portion placed on the spring seat cylindrical body of the key housing, and the key top A key return/contact pressing coil spring is provided which is integrally formed with a medium-diameter coil portion into which a protrusion provided on the holder is fitted, and a small-diameter coil portion connected to the medium-diameter coil portion, and further includes a coil spring for key return and contact pressing. A protruding part is formed in the small diameter coil part of the key housing so that at least a part of the winding diameter of the protruding part protrudes outward, and the protruding part is able to overcome the stepped part by the force applied when the key top is pressed down and returned to the key housing. It is characterized by the fact that it is provided in

<Function> The push button switch of the present invention is constructed as described above. When assembling, first drop the coil spring into the spring seat cylinder of the key housing with the small diameter coil part facing downward, and then insert the large diameter seat at the top. The coil spring is set by placing the winding part on the stepped part of the upper part of the spring seat cylinder. Next, the key top can be easily assembled from one direction by fitting the key top onto the outer periphery of the spring seat cylinder so that the protruding portion is fitted into the medium diameter coil portion of the coil spring. In this state, the protruding part of the key top is fitted into the medium diameter coil part of the coil spring, and the tip thereof comes into contact with the continuous part of the medium diameter coil part and the small diameter coil part.
On the other hand, since the large-diameter end winding part is placed on the step at the top of the spring seat cylinder and its position is regulated, the medium-diameter coil part expands under some tension, and the reaction force causes the key top to move upward. Although it receives a push-up force, the key top is regulated by the stopper, so it can be positioned. Here, the medium diameter coil part of the coil spring acts as a tension spring to return the key top, the small diameter coil part acts as a compression spring to push down the movable contact, and the protruding part of the small diameter coil part acts as a spring seat tube. It functions to convey the feeling of movement to the operator when climbing over a step on the body periphery. In other words, when the key top is pressed, the key top descends along the spring seat cylindrical body, so the medium-diameter coil part of the coil spring receives force from the protrusion of the key and expands, and the protrusion engages with the stepped part to form the protrusion. The small-diameter coil portion between the small-diameter coil portion and the protrusion is compressed, and when this compressive force becomes greater than the force that holds the protrusion of the small-diameter coil portion on the step, the protrusion climbs over the step. At this time, the compressed small-diameter coil portion is released and expanded, pushing down the movable contact and closing the electrical contact. At the same time, the operator can sense that the electrical contact is closed by feeling when the protrusion passes over the step. Next, when the key top is released, the key top moves upward due to the contraction force of the medium diameter coil part of the coil spring and the expansion force of the small diameter coil part, and the electrical contact is opened. When the key top moves further upward, the protruding part of the small diameter coil part The key top engages with the lower part of the step, but since the contraction force of the medium-diameter coil section is greater than the force required for the protrusion to get over the step, the protrusion gets over the step, and this causes the key top to Return to original position.

On the other hand, each time the key top is released from the pressed state, a rotational force is applied to the ring body rotatably arranged along the inner circumference of the spring seat cylinder by the protruding part of the coil spring through the stepped part. It will be done. Therefore, the contact position between the protruding part and the stepped part changes each time the switch is opened and closed, thereby preventing deterioration of the switch mechanism due to wear and tear.

<Example> An example of the present invention will be described below based on FIGS. 1 to 13.

Figure 1 is a cross-sectional view of the push button switch when its contacts are open.
FIG. 2 is a cross-sectional view when the contact is opened, and in the figure, 5 is a substrate, 6 is a fixed contact provided on the top surface of the substrate 5, 7 is a spacer, and 8 is a contact provided on the substrate 5 via the spacer 7. A movable contact 9 opposite to a fixed contact 6 is provided on the lower surface of the flexible member. 10 is a switch mounting frame, 11 is a key top, and a protrusion 11a provided at the center of the bottom surface;
Support arm 11 protruding from the outside of the protrusion 11a
b, an engaging inclined claw 11c provided at the tip of the support arm 11b, and a key body 11d.

FIG. 3 shows a coil spring 12, which is connected to a large-diameter end-turning part 12a formed at the upper end, and successively includes a medium-diameter coil part 12b, a parallel-winding part 12c, and a part of the winding diameter partially outside. A small-diameter coil portion 12d having a protruding portion 12f protruding in the direction, and a small-diameter end-turn portion 12e are integrally formed.

Reference numeral 13 designates a key housing, which includes a bottom surface 13a, a spring seat cylindrical body 13b erected in the center of the bottom surface 13a, a stepped portion 13c formed protruding from an inner circumferential surface 13w of the spring seat cylindrical body 13b, and an outer periphery thereof. A guide portion 13d protruding from the guide portion 13d, a stopper portion 13e protruding from the inside of the upper end of the guide portion 13d, a flange 13f protruding outward from the guide portion 13d, and a locking claw 13g;
It is formed by a stepped portion 13h provided at the upper end of the spring seat cylinder 13b. The key housing 13 is mounted with the switch mounting bracket 10 held between a flange 13f and a locking pawl 13g.

The push button switch is assembled using the above-mentioned parts according to the following construction procedure.

First, the small-diameter end turn portion 12e of the coil spring 12 is dropped downward into the through hole of the spring seat cylinder 13b installed upright in the center of the key housing 13, and the large diameter end portion 12e of the coil spring 12 is dropped into the upper end stepped portion 13h of the spring seat cylinder 13b. Diameter end winding part 12a
is placed to regulate the position of the coil spring 12. In this state, a certain distance l remains between the lower end small diameter end turn portion 12e of the coil spring 12 and the flexible member 8. Next, the inclined claw 11 of the support arm 11b
c into the key top 11 with the stopper portion 13e guided between the spring seat cylinder 13b and the guide portion 13d of the key housing 13, and the key top 1
1, the support arm 11b is elastically deformed and the inclined claw 11c at the tip passes over the stopper portion 13e of the key housing 13. In this state, the protruding portion 11a of the key top 11 is inserted into the medium diameter coil portion 12b of the coil spring 12, and the medium diameter coil portion 12
b and the small diameter coil portion 12d are connected to each other.

On the other hand, since the position of the large-diameter end-turn portion 12a of the coil spring 12 is restricted by the upper end stepped portion 13h of the spring seat cylinder 13b, the medium-diameter coil portion 12b is expanded by receiving some tension. As a result, the projection 11a of the key top 11 receives an upward force from the coil spring 12, so that the inclined claw 11c at the tip of the support arm 11b of the key top 11 comes into contact with the stopper 13e of the key housing 13. Positioning is performed, and the small-diameter end turn portion 12e and the flexible member 8 are maintained at the distance l described above.

The push button switch is assembled and constructed in the manner described above.

Next, the operation of the push button switch will be explained. Shown in Figure 1. When the key top 11 is pressed down from the state when the contacts are opened, the key top 11 descends along the spring seat cylinder 13b using the guide portion 13d of the key housing 13 as a guide, so that the coil spring 1
The second parallel winding portion 12c is the protrusion 1 of the key top 11.
A force is received from 1a, which causes the medium diameter coil portion 1
2b expands.

FIG. 4 is a diagram showing the relationship between the amount of movement when the key top 11 is pressed down and the pressing force of the key top 11. Points A to F in this diagram correspond to the coil springs shown in FIGS. 5 a to e. This corresponds to a detailed diagram of the positional relationship between the 12 protruding parts 12f and the stepped part 13c provided on the spring seat cylinder 13b.

Point A is the state before the key top 11 is pressed down, and point B is the state where the small diameter coil portion 12d is compressed because the protruding portion 12f of the coil spring 12 is engaged with the stepped portion 13c due to the pressing down of the key top 11. This shows a state in which the key top 11 is pressed down, and the reaction force increases against the force pushing down the key top 11. When the pressing force becomes larger than this reaction force, the protrusion 12 of the coil spring 12
f climbs over the stepped portion 13c. The dot C represents the state immediately before overcoming.

The small diameter coil portion 12d of the coil spring 12 was compressed when the protruding portion 12f climbed over the step portion 13c.
is opened and expanded, so that it comes into contact with the flexible member 8, and by bending this, the movable contact 9 is brought into contact with the fixed contact 6 on the substrate 5, and the two contacts are closed. Realize. In addition, in this state, key top 1
1 has not yet reached its lowering limit and can be lowered until the lower end of the support arm 11b of the key top 11 comes into contact with the bottom surface 13a of the key housing 13.
The hot point indicates this lower limit.

Here, the operator can sense the open state of the contact by the decrease in the pressing force of the key top 11 from point C to point D when the protruding portion 12f passes over the stepped portion 13c. Next, when you release your finger that was pressing down on the key top 11, the key top 11 moves upward due to the force that causes the medium diameter coil portion 12b of the coil spring 12 to contract and the force that causes the small diameter coil portion 12d to expand. Since the force with which the winding portion 12e presses the flexible member 8 becomes weaker, the movable contact 9 separates from the fixed contact 6 and the contact is opened.

When the key top 11 further rises, the protruding portion 12f of the coil spring 12 engages with the lower surface of the stepped portion 13c. Here, since the contractile force of the medium-diameter coil portion 12b is greater than the force required for the protrusion 12f to overcome the stepped portion 13c, the protrusion 12
The point f climbs over the stepped portion 13c and returns to its original state at point A.

In the above manner, the opening and closing operations of the contacts are performed,
During this time, the operator can confirm that the protruding portion 12f is the stepped portion 13c.
You can feel the opening and closing of the contacts by sensing the change in key press force when overcoming the problem.

FIG. 6 is a schematic cross-sectional view showing another embodiment of the present invention. That is, the ring body 13j is rotatably arranged within the spring seat cylinder 13b and along its inner periphery. Moreover, a stepped portion 13c is provided on the inner circumferential surface 13k of the ring body 13j in a protruding manner, similar to the embodiment described above. Coil spring 1 when operating the push button switch
2 and the stepped portion 13c have substantially the same effect as described above. A particular difference is that when the key top 11 is pressed and released, the wheel 13j rotates along the inner periphery of the spring seat cylinder 13b. When the key top 11 is released from the depressed state, the protrusion 12f comes into contact with the lower surface of the step 13c and overcomes it, as described above.

On the other hand, since the coil spring has a spiral shape as shown in the figure, the protrusion 12f is formed in a substantially inclined state. Therefore, when it comes into contact with the lower surface of the stepped portion 13c and is pushed up, it acts as a biasing force against the stepped portion 13c itself. Due to this biasing force, the ring body 1
3j rotates slightly along the inner circumference of the spring seat cylinder 13b.

Therefore, each time the push button switch is opened or closed, the ring body 13j
rotates, and the contact position of the stepped portion 13c with respect to the protruding portion 12f of the coil spring 12 changes.

If the contact position changes due to the rotation of the wheel 13j, wear and tear will occur on the stepped portion 13c and the protruding portion 12
Deformation of f is eliminated, deterioration of the switch mechanism is prevented, and there is no decrease in opening/closing feel.

In each of the above embodiments, the flexible member 8 has a flexible contact 9.
Although an example of a so-called membrane contact in which a fixed contact 15 is provided on a substrate 5 has been described, as shown in FIG.
The present invention can also be applied to a capacitance change type push button switch in which a movable contact 16 is provided on the small diameter end turn portion 12e of the coil spring 12.

Further, the shape of the protrusion 12f formed on the small diameter coil portion 12d of the coil spring 12 is as shown in FIG.
A perfect circular shape with a large radius as shown in Fig. 8 viewed from the direction of the arrow, an elliptical shape as shown in Fig. 9, and a
Partially protruding deformed shapes as shown in Figure 0, etc.
It can be formed into various shapes, and the same effects can be achieved in any case.

Furthermore, the stepped portion 13c provided on the inner circumferential surface of the spring seat cylinder 13b of the key housing 13 may be provided in a ring shape around the entire inner circumferential surface as shown in FIG.
It may be provided partially as shown in the figure. However, if the stepped portion 13c is partially provided, the coil spring 12
must be arranged so that the protrusion 12f always corresponds to the step 13c. Therefore, a positioning groove 13i is provided at the upper end of the spring seat cylinder 13b, and the first
As shown in Figure 3A and Figure 13B, which is a plan view thereof, a rotation stopper projection 12g is provided at the end of the large-diameter end turn portion 12a of the coil spring 12, and the projection 12g is inserted into the groove 13i to assemble. There is a need.

<Effects of the invention> As explained above, according to the invention, a mechanism for transmitting the opening/closing sensation of a contact point to the operator is constructed by one coil spring and a stepped portion provided on the circumferential surface of the spring seat cylinder. Therefore, there is no need for an actuator with a complicated shape as in the past. Therefore,
The overall structure can be simplified, and
Since the coil spring and key top can be easily assembled from one direction, costs can be significantly reduced.

Moreover, since the position of the stepped portion relative to the coil spring changes each time the push button switch is opened and closed, local wear and tear does not occur, thereby improving the reliability of the push button switch and extending its mechanical life.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the push button switch when the contact is open, Fig. 2 is a sectional view showing the state when the contact is closed, Fig. 3 is a configuration diagram of the coil spring, and Fig. 4 is a sectional view showing the state when the contact is closed.
FIGS. 5a to 5e are partial sectional views illustrating the positional relationship of the coil springs corresponding to points A to F in FIG. 6 is a cross-sectional view showing the arrangement of the wheels, FIG. 7 is a cross-sectional view showing another embodiment, and FIG.
9 and 10 are plan views showing modifications of the shape of the protruding portion of the coil spring as viewed from the - arrow direction in FIG. 3, and FIG. 11 and FIG. A cross-sectional view showing a modified example of the stepped shape of the inner circumferential surface of the seat cylinder, FIGS. FIG. 15 is a cross-sectional view of the state when the contact is closed, showing an example, and FIG. 16 is a diagram showing the relationship between the key movement amount and key pressing force when the key is operated. It is. 5... Board, 6... Fixed contact, 9... Movable contact, 11... Key top, 11a... Protrusion, 1
2...Coil spring, 12a...Large diameter end turn portion, 12
b...Medium diameter coil part, 12d...Small diameter coil part,
12f...Protrusion, 13...Key housing, 1
3a...bottom surface, 13b...spring seat cylinder, 13c...
...stepped portion, 13e...stopper portion, 13j...circular body.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A push button switch that opens and closes an electrical contact consisting of a fixed contact provided on a board and a movable contact operated by a key top, with a spring seat cylindrical body erected at the center of the bottom surface. The key housing is fitted into a spring seat cylindrical body of the key housing.
and a key top that is slidable while being regulated by a stopper, and a large-diameter end turn portion that is placed in the spring seat cylinder of the key housing and placed on the upper stepped portion of the cylinder, and a large-diameter end turn portion that is provided on the key top. A key return/contact pressing coil spring is provided which is integrally formed with a medium diameter coil portion into which the protrusion is inserted and a small diameter coil portion connected to the medium diameter coil portion, and the small diameter coil portion of the coil spring is provided with a coil spring for key return and contact pressing. A protruding portion is formed in which at least a part of the winding diameter of the key housing protrudes outward, and a stepped portion is formed on the key housing so that the protruding portion can be climbed over by the force applied when the key top is pressed and returned. A push button switch that is characterized by: (2) The push button switch according to claim 1, wherein the stepped portion is provided protruding from the inner circumferential surface of the spring seat cylindrical body. (3) The push button switch according to claim 1, wherein the wheel body is rotatably arranged along the inner periphery of the spring seat cylinder, and a stepped portion is provided on the inner peripheral surface of the wheel body.