JPH0660769A - Press button switch - Google Patents

Abstract

PURPOSE:To provide a press button switch which can be thinned without causing troubles in rising and lowering movement of a keytop by using a holding part which can fold the back side of a keytop while supporting and fixing it and holding the keytop in the way the keytop can rise and lower freely without standing a guide wall in a housing. CONSTITUTION:Leg pieces 29, 32 of both link parts 26, 27 are connected each other along a long hole 32b in the way a connection pin 29b can move freely and at the same time each connecting projections 29a, 32a are fitted in connecting recessed parts of a housing in the way they can slide freely. Corresponding to the height of a keytop, the crossing angle between the leg pieces 29, 32 are changed freely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push button switch used as a key switch of a keyboard device, and more particularly to a push button switch suitable for thinning.

[0002]

2. Description of the Related Art FIG. 16 is a sectional view showing a conventional example of a push button switch of this type. In the figure, reference numeral 1 is a support plate made of a hard material such as a metal plate, and a membrane switch 2 is mounted on the support plate 1. In this membrane switch 2, a movable contact 4 provided on the lower surface of a flexible upper sheet 3 is made to face a fixed contact 6 provided on the upper surface of a lower sheet 5, and a spacer 7 is provided between both sheets 3 and 5.
Is a switch element formed by interposing. On the membrane switch 2, a synthetic resin housing 8 in which an annular guide wall 8a is erected is placed.
The opening 8b on the inside is positioned above the movable contact 4. Then, the stem 10 protruding from the central portion of the back surface of the synthetic resin key top 9 is inserted into the opening 8b so as to be slidable along the inner wall surface of the guide wall 8a,
A coil spring 11 that functions as an actuator is mounted inside the stem 10 by strong fitting.
A return spring 12 installed between the housing 8 and the key top 9 outside the guide wall 8a is for urging the key top 9 upward.

In the push button switch constructed as described above, when the operator pushes the key top 9 against the elastic force of the return spring 12, the stem 10 descends along the inner wall surface of the guide wall 8a. The coil spring 11 in the stem 10 contacts the upper sheet 3 of the membrane switch 2 and is gradually compressed. Therefore, when the key top 9 is pushed for a predetermined stroke, the elastic force of the coil spring 11 causes the upper sheet 3 to bend downward, the movable contact 4 comes into contact with the fixed contact 6, and switching from off to on is performed.

Further, when the operator removes the pressing operation force on the key top 9 in such an ON state, the key top 9 is pushed up to the initial position by the elastic force of the return spring 12, so that the coil spring 11 moves from the upper seat 3. When the upper sheet 3 is separated from the fixed contact 6, the movable contact 4 is separated from the fixed contact 6, and the off state shown in FIG. 16 is restored.

[0005]

By the way, for pushbutton switches incorporated in keyboard devices and the like, there is an increasing demand for thinning in recent years. In the case of the above-mentioned conventional pushbutton switches, the stem 10 is Since the key top 9 is held in the housing 8 so as to be able to move up and down by slidingly contacting the inner wall surface of the guide wall 8a, the height of the guide wall 8a can be reduced in order to secure a desired operation stroke and make the push button switch thin. If the size is suppressed as much as possible, the amount of insertion of the stem 10 into the guide wall 8a will inevitably decrease. As a result, due to the minute clearance between the stem 10 and the guide wall 8a required for sliding, the key top 9
Is easily tilted with respect to the housing 8, so that, for example, when the operator pushes the edge portion of the key top 9 to perform an end push, the stem 10 is caught by the guide wall 8a, which hinders the vertical movement of the key top 9. Therefore, it is easy to cause deterioration of operation feeling and malfunction.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a push button switch which can be made thinner without hindering the raising and lowering operation of the key top.

[0007]

SUMMARY OF THE INVENTION The above-mentioned object of the present invention is to provide a key top supported by a housing so as to be able to move up and down,
A push button switch including an elastic member for urging the key top upward and a switch element, the push button switch performing a switching operation of the switch element by pressing the key top against the elastic member, is supported at one end. A shaft is provided with first and second link members having engaging projections at the other end, and a connecting pin provided on either one of the first and second link members is provided in an elongated hole provided on the other. By movably engaging, both link members are connected to each other in an X shape, each supporting shaft is rotatably supported on the back surface of the key top, and each engaging protrusion is slidably supported on the housing. It is achieved by

[0008]

According to the above-mentioned means, the support shafts of the first and second link members can support the key top by receiving the elastic force of the elastic member, and the connecting pin is provided along the elongated hole. Since the engaging projections are movable and slidable with respect to the housing, the first and second link members are substantially X-shaped while maintaining a constant distance between the respective support shafts supporting the key tops. The crossing angle that intersects and is connected to is changeable. Therefore, when the pressing operation force is applied to the key top and the first and second support shafts are pushed in, both link members gradually increase the angle at which they intersect when viewed from the key top side, but support the key top. Even if both link members are folded in this way, the position of each engaging projection can be regulated by the housing, so that the key top can be lowered straight without the guide wall being erected on the housing. Furthermore, since it is not necessary to slide the key top with respect to both link members, there is no concern that the shape of the back surface of the key top becomes complicated or large.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view showing an internal structure of a push button switch according to a first embodiment of the present invention, FIG. 2 is a sectional view of the push button switch in an off state, and FIG. 3 is a sectional view of the push button switch in an on state,
FIG. 4 is a perspective view of a keytop holder incorporated in the push button switch, FIG. 5 is an exploded perspective view of the keytop holder, and FIGS. 6A to 6D are operation explanatory views of the keytop holder. is there.

In these figures, reference numeral 15 is a support plate made of a hard material such as a metal plate, and a membrane switch 16 is mounted on the support plate 15. In this membrane switch 16, a movable contact 18 provided on the lower surface of a flexible upper sheet 17 is made to face a fixed contact 20 provided on the upper surface of a lower sheet 19, and both sheets 17, 1
It is a switch element in which a spacer 21 is provided between 9 parts. Reference numeral 22 is a synthetic resin housing, reference numeral 2
Reference numeral 3 denotes a synthetic resin key top that is held above the housing 22 so as to be able to move up and down. The housing 22 has an opening 22a above the movable contact 18, and
A pair of inward engagement recesses 22b and an outward pair of engagement recesses 22c are provided for slidably engaging engagement protrusions of a keytop holder, which will be described later. And
A well-known click rubber 24 is mounted on the housing 22. The skirt-shaped side wall portion 24a is formed into a shape that supports the driving portion 24b and is capable of buckling deformation. The drive portion 24b of the click rubber 24 is located above the movable contact 18.

Reference numeral 25 is a synthetic resin key top holder, and this key top holder 25 has a substantially E-shaped link member 26 and a substantially U-shaped link member 27, as is apparent from FIGS. It is configured by combining. Here, one of the link members 26 has an outward engaging projection 29a at its tip end from both ends of a support shaft 28 for supporting and fixing one side of the back surface of the key top 23, and is directed inward at a substantially central portion. A pair of external leg pieces 29 having the connecting pins 29b of the above are extended in parallel, and an operating piece 30 shorter than the external leg piece 29 is extended from the center of the support shaft 28. Is an elastic piece having a little flexibility against an external force in the plate thickness direction, and when the key top holding body 25 is incorporated into the housing 22, the tip end of this operation piece 30 is the driving portion 24b of the click rubber 24. It is designed to be in constant contact with the top surface.
The other link member 27 is inwardly directed toward the tip end in a direction parallel to and intersecting with the outer leg piece 29 from both ends of a support shaft 31 for supporting and fixing the other back surface of the key top 23. Is formed by extending a pair of internal leg pieces 32 each having an engaging projection 32a and a substantially heart-shaped elongated hole 32b at a substantially central portion, and a snap using the inclined surface 32c on the upper portion of the elongated hole 32b. The connection pin 29b is loosely inserted into each of the long holes 32b by an in, and the corresponding outer leg piece 29 and inner leg piece 32 are connected so that the connection pin 29b is movable along the long hole 32b. The link members 26 and 27 are integrated to form a key top holding body 25. Therefore, the key-top holding body 25 applies a pressing operation force to the key-top 23 so that both the link members 2
When the support shafts 28 and 31 of 6, 27 are pushed in downward, as shown in FIGS. 6A to 6D, the outer leg piece 29 and the inner leg piece which are connected to intersect in a substantially X shape. It is possible to fold both link members 26 and 27 so that the angle at which 32 intersects gradually when viewed from the key top 23 side increases, and the height dimension of the key top holding body 25 gradually decreases. When the key-top 23 is pressed in this manner, the connecting pin 29b of the outer leg piece 29 and the elongated hole 32b of the inner leg piece 32 are mutually complementary movement regulated, that is, the connecting pin 29b is elongated hole 32b. The peripheral wall restricts the movement of the support shaft 28 and the engagement projection 29a in the direction orthogonal to the straight line passing through the respective rotation centers, and the elongated hole 32b is supported by the engagement projection 29b in the support shaft 31 and the engagement projection 29a. Movement in a direction orthogonal to a straight line passing through each rotation center of 32a is restricted. Therefore, the key top 23 supported by the support shafts 28 and 31 of the link members 26 and 27, respectively, when the pressing operation force is applied,
It is possible to move up and down while maintaining the level with the housing 22.

However, the key top holding body 25 is constructed such that the support shaft 28 of the outer link member 26 is attached to the inner link member 2 of the support shaft 28.
The dimension is set so that the inner leg pieces 32 of No. 7 do not come into contact with each other. Specifically, the distance D from the long hole 32b to the support shaft 28 is the length from the long hole 32b to the tip of the inner leg piece 32. L
Is set larger than that (see FIG. 6). Therefore,
Both link members 26, 27 can be folded until the outer leg piece 29 and the inner leg piece 32 fall to the side.

When the key top holder 25 is attached to the housing 22, the outward engaging protrusions 29a of the outer leg pieces 29 are respectively attached to the inclined surfaces 22 shown in FIG.
Inward engaging recess 2 by snap-in using d
2b, and the inward engaging projections 32a of the inner leg pieces 32 are respectively outwardly engaged by snap-in using the inclined surface 22e shown in FIG.
Insert it inside. Thereby, the engaging protrusions 29a and 32a
Are slidably engaged with the engaging recesses 22b and 22c, respectively, and the outer side of each outer leg piece 29 and the inner side of each inner leg piece 32 are positionally regulated by the housing 22. Further, when the key top holder 25 is assembled in the housing 22 in this way, the drive portion 24b of the click rubber 24 previously assembled in the housing 22 elastically contacts the tip end portion of the operation piece 30, so that the link is made via this operation piece 30. Member 26
The support shaft 28 of the link member 2 is biased upward, and the inner link member 2 is connected via the connecting pin 29b of the link member 26.
The support shaft 31 of No. 7 is also biased upward.

As shown in FIG. 1, the housing 22 has a projection 22f at a position diagonally opposed to the engaging recess 22b.
Is provided, and the key top holder 25 is attached to the housing 22.
Attached to the engaging projection 29 at the tip of the outer leg piece 29.
Since the back surface side of a is close to the projection 22f, the engagement protrusion 29a is not easily disengaged from the engagement recess 22b even when a strong external force such as impact is applied.

The push button switch constructed as described above is
The support shafts 28 and 31 of the link members 26 and 27 of the key top holder 25 receive the elastic force of the click rubber 24 to support both sides of the back surface of the key top 23. Since the outer leg pieces 29 and the inner leg pieces 32 of 26 and 27 are connected so that the angle at which they intersect each other can be changed, and the position of each leg piece 29, 32 is regulated by the housing 22, After all, the key top 23 is held above the housing 22 so as to be able to move up and down.

Therefore, when the operator applies a pressing operation force to the key top 23 and pushes both support shafts 28 and 31 against the elastic force of the click rubber 24, both support shafts 28 and 31 are pushed.
Rotates on the spot, and each engaging protrusion 29a, 32
a slides in the corresponding engagement recesses 22b and 22c,
The outer leg piece 29 and the inner leg piece 32, which are connected so as to intersect each other in a substantially X shape, gradually increase the angle at which they cross each other when viewed from the key top 23 side. Is pushed downwards,
When the driving portion 24b is lowered by a predetermined amount, the side wall portion 24a
Buckles and a click feeling is generated, and the drive portion 24b is pushed in with a force so that the membrane switch 16
The upper sheet 17 of the vehicle. As a result, the upper sheet 17 bends downward and the movable contact 18 comes into contact with the fixed contact 20, and switching from the OFF state shown in FIG. 2 to the ON state shown in FIG. 3 is performed.

Further, when the operator removes the pressing operation force on the key top 23 in such an ON state, the buckled click rubber 24 returns to its original shape by its own elasticity, so that the driving portion 24b rises. The operation piece 30 is pushed up by the user, and the two link members 2 are folded.
6, 27 stand up, the key top 23 is pushed up to the initial position, the bending of the upper sheet 17 is eliminated, the movable contact 18 is separated from the fixed contact 20, and the state returns to the off state.

As described above, in the above embodiment, the link member 2
Both link members 26 that support the key top 23 by using a key top holding body 25 that is a combination of 6, 27 and that can change the crossing angle according to the height position of the key top 23,
Since the position of each leg piece 29, 32 of 27 is regulated by the housing 22, the key top 23 can be moved up and down straight even if the housing 22 is not provided with a guide wall unlike the conventional product. It is difficult for the parts to be caught between the parts that hinders the lifting and lowering operation of the switch 23, so that the push button switch can be significantly thinned without impairing the operability and reliability.

Further, in the above embodiment, the dimension is set so that the tip of the inner leg piece 32 of the inner link member 27 does not come into contact with the support shaft 28 of the outer link member 26.
As shown in FIG. 6 (d), both link members 26 and 27 can be folded until they lie straight down, which has the advantage that the stroke lowest point of the key top 23 can be set to an extremely low position. This is convenient for promoting thinning.

Further, the key top holding body 25 used in the above embodiment has the leg pieces 29 and 32 of the link members 26 and 27.
By making the connecting pin 29b slidable along the long hole 32b at the intersecting part of and the engaging projections 29a, 32a of the tip ends of the leg pieces 29, 32 slidable with respect to the housing 22, Since the link members 26 and 27 can be folded while keeping the distance between the two support shafts 28 and 31 located on the base end side of the leg pieces 29 and 32 constant, both the key tops 23 are supported. A support structure for fixing the shafts 28 and 31 is realized. That is, for example, both link members 2 with the intersection of the leg pieces 29 and 32 as the center of rotation.
6, 27 can be folded, but in that case, a support structure in which the key top 23 is slidable with respect to both link members 26, 27 must be adopted, and the shape of the back surface of the key top 23 is complicated. It may become larger or larger.
However, if both link members 26 and 27 can be folded without laterally shifting the base end portions of the leg pieces 29 and 32 as in this embodiment, the key top 23 can simply support shafts 28 and 31.
As shown in FIGS. 2 and 3, the shape of the back surface of the key top 23 is simple and small, so that it has good formability and is suitable for thinning. Since the key top 23 can be attached to the key top holder 25 by snap-in, it is easy to assemble.

In addition, the key top holder 25 used in the above embodiment has the outward engaging projections 29a of the outer leg pieces 29.
Are respectively engaged with the inward engaging recesses 22b of the housing 22, and the inward engaging projections 32 of the respective inner leg pieces 32 are engaged.
a is an outward engaging recess 22c of the housing 22
The position of each leg 29, 32 and by extension both link members 26, 27 can be regulated by the housing 22 by engaging with the outer leg 29 and inner leg 32 connecting the intersections. Is always regulated from the separating direction. Therefore, the connection between the two leg pieces 29, 32 is guaranteed, and even if a strong external force is applied, the respective engagement protrusions 29a, 32a are unlikely to be disengaged from the corresponding engagement recesses 22b, 22c, and the housing of the keytop holder 25 is secured. The accident of dropping from 22 has been prevented.

Furthermore, in the key top holder 25 used in the above embodiment, one link member 26 has an operation piece 30.
Is provided, and when the operator pushes in the key top 23, the operation piece 30 presses and drives the movable contact 18 via the drive portion 24b of the click rubber 24. Therefore, the stem can be omitted, and the amount of lowering of the drive portion 24b required for switching can be set smaller than the operation stroke of the key top 23. That is, the link member 26 having the operation piece 30 rotates about the tip of the external leg piece 29 as a movable fulcrum, but the turning radius of the tip of the operation piece 30 elastically contacting the top surface of the drive portion 24b is: Since it is about half the turning radius of the support shaft 28 that is directly pushed into the key top 23, the drive portion 24b
The pushing amount of the key rubber can be reduced to about half the pushing amount of the key top 23. As a result, the deformation amount of the click rubber 24 due to the operation is reduced, the life thereof is extended, and high reliability can be maintained for a long time. . Further, since the turning radius of the tip end portion of the operation piece 30 that is the point of action is about half the turning radius of the support shaft 28 that is the force point, the lever principle
Even if the pressing operation force applied to the support shaft 28 is small, the click rubber 24 can be pushed in with a large force through the operation piece 30, and therefore, there is an advantage that the pressing operation force can be reduced. Moreover, in the above-described embodiment, the operation piece 30 itself is an elastic piece, and the operation piece 30 is slightly bent after the driving portion 24b of the click rubber 24 is pushed to the lowest point of the stroke, so that it is an extremely thin push button switch. However, it is possible to reliably obtain an overstroke and expect a good operating feel.

In the first embodiment, the case where the outer leg piece 29 of the one link member 26 is set longer than the inner leg piece 32 of the other link member 27 has been described.
The lengths of both leg pieces 29, 32 can be appropriately selected. For example, as shown in FIG. 7 as a second embodiment, both leg pieces 29, 32 are provided.
May have substantially the same length.

Further, in the first embodiment, the outer link pieces 29 of one of the link members 26 are connected to the other link member 2 of the other.
The case where both of the inner leg pieces 32 of No. 7 are connected so as to be positioned inside is described, but as shown in FIG. 8 as the third embodiment, both leg pieces 29 of one link member 26 are described.
On the other hand, both leg pieces 32 of the other link member 27 may be located inside and outside.

The number of leg pieces provided on both link members does not necessarily have to be two. For example, as shown in FIGS. 9 and 10 as the fourth embodiment, one of the leg pieces described in the first embodiment is used. It is also possible to omit one external leg piece 29 of the link member 26 and one internal leg piece 32 of the other link member 27, respectively, and connect the remaining pair of leg pieces 29, 32 to form a key top holder. is there.

Further, in each of the above-mentioned embodiments, the case where the click rubber 24 is pressed by the action piece 30 provided on one of the link members 26 has been described, but as shown in FIG. Both link members without 2
It is also possible to form a key top holder by combining 6 and 27 and press and drive the click rubber 24 by a member other than the link holder, for example, the back surface of the key top 23.

Further, the shape of the connecting pin and the long hole for connecting the leg pieces of both link members can be appropriately selected, and the connecting pin may be loosely inserted from the inside into the long hole, contrary to the above embodiments. . Further, in each of the above embodiments, the operation piece provided on the link member is elastically contacted with the click rubber, but both link members are biased upward by an elastic member other than the click rubber, or without an elastic member. An operation piece that can directly drive the movable contact may be adopted.

Further, the sixth and seventh embodiments described below are also conceivable as the same effects as the above-mentioned effects due to the above-described operations.

First, in the sixth embodiment shown in FIGS. 12 and 13 (a)-(d), instead of the engagement between the elongated hole 32b and the connecting pin 29b of the first embodiment described above, the intersecting internal parts Leg 4
Heart-shaped projections 44 and 45 are provided on the leg pieces 42 and 43 of the 0 and the outer leg piece 41, respectively. Further, the vertical relationship between the two heart-shaped protrusions 44 and 45 is reversed at the two intersections. FIG. 12 shows the outer leg piece 41 and the inner leg piece 40.
FIGS. 13 (a) to 13 (d) are operation explanatory views of the key top holder having such a configuration, and the heart-shaped projection 4 is shown.
It is shown that the similar operation is performed as described above by the contact sliding between the four and 45.

Next, the seventh embodiment shown in FIGS. 14 and 15 (a)-(d) is the slot 32 of the above-mentioned fourth and fifth embodiments.
Instead of the engagement between b and the connecting pin 29b, the connecting pins 48 and 50 are formed on each of the intersecting leg pieces 46 and 47, and the shape of a part of the elongated hole 32b corresponding to the connecting pins 48 and 50. Notched portions 49 and 51 are provided one by one. 14 is a perspective view of the leg pieces 46 and 47, FIG.
(A)-(d) is operation | movement explanatory drawing of the keytop holding body of such a structure, and connecting pin 48,50 and notch part 49,
Engagement with 51 is shown to perform a similar operation as described above.

[0031]

As described above, according to the present invention,
Both link members are movably connected by a connecting pin and a long hole, a support shaft provided at one end of each link member is rotatably supported on the back surface of the key top, and an engaging projection provided at the other end is provided on the housing. Since it is supported slidably, it is not necessary to stand a guide wall on the housing, and the push button switch can be made significantly thinner without hindering the lifting operation of the key top. Since it is not necessary to slide the key members with respect to both link members, there is also the effect that the shape of the back surface of the key top is not complicated or large and the key top is easy to mold.

[Brief description of drawings]

FIG. 1 is a plan view showing an internal structure of a push button switch according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the push button switch in an off state.

FIG. 3 is a cross-sectional view of the push button switch in an ON state.

FIG. 4 is a perspective view of a keytop holder incorporated in the push button switch.

FIG. 5 is an exploded perspective view of the key top holder.

FIG. 6 is an operation explanatory view of the keytop holder.

FIG. 7 is a perspective view showing a second embodiment of the keytop holder.

FIG. 8 is a perspective view showing a third embodiment of the keytop holder.

FIG. 9 is a perspective view showing a fourth embodiment of the keytop holder.

FIG. 10 is an exploded perspective view of the key top holder shown in FIG.

FIG. 11 is a perspective view showing a fifth embodiment of the keytop holder.

FIG. 12 is a perspective view showing a sixth embodiment of the keytop holder.

13 is an operation explanatory view of the keytop holder shown in FIG.

FIG. 14 is a perspective view showing a seventh embodiment of the keytop holder.

FIG. 15 is an operation explanatory view of the keytop holder shown in FIG.

FIG. 16 is a cross-sectional view showing a conventional push button switch.

[Explanation of symbols]

 16 Membrane Switch (Switch Element) 18 Movable Contact 20 Fixed Contact 22 Housing 22b, 22c Engagement Recess 23 Key Top 24 Click Rubber (Elastic Member) 25 Key Top Holder 26 (First) Link Member 27 (Second) ) Link member 28 Support shaft (first support portion) 29, 32 Leg pieces 29a, 32a Engagement protrusion 29b Connecting pin 30 Operation piece 31 Support shaft (second support portion) 32b Long hole 44, 45 Heart-shaped protrusion 48 , 50 Connecting pin 49,51 Notch

Claims (3)

[Claims] 1. A key top supported by a housing so as to be able to move up and down, and an elastic member for urging the key top upward.
A push button switch comprising a switch element and performing a switching operation of the switch element by pressing the key top against the elastic member, a first and a support shaft at one end and an engagement protrusion at the other end. A second link member is provided, and a linking pin provided on either one of the first and second link members is movably engaged with an elongated hole provided on the other, thereby linking both link members. X
A push button switch characterized by being connected in a letter shape, rotatably supporting each of the support shafts on the back surface of the key top, and slidably supporting each of the engaging projections on the housing. 2. The push button switch according to claim 1, wherein
A push button switch comprising a pair of leg pieces extending parallel to the first and second link members and bridging the leg pieces with the support shaft. 3. The push button switch according to claim 1 or 2, wherein the first and second link members are configured so as to fit within substantially the same plane at a lowermost position of the key top. Push button switch.