JPH0636651A - Pushbutton switch - Google Patents

Abstract

PURPOSE:To make it possible to reduction of a pushing force for operating a keytop, to prolong the life of a switch and freely set the touch of control of the switch. CONSTITUTION:The leg pieces 29, 32 of link members 26, 27 are connected to each other in such a manner that the angle at which they cross each other is freely varied according to the height of a keytop 23. The engaging protrusion 29a, 32a of each leg piece 29, 32 is engaged with a housing 22 so as to regulate the position of the housing and an operating piece 30 provided to one of the link members (26) is brought into elastic contact with click rubber 24.

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 which is used as a key switch of a keyboard device and in which a switch element such as a membrane switch is pressed by an elastic member.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view showing a conventional example of a push button switch of this type.

In FIG. 1, 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. This membrane switch 2
Is such that the movable contact 4 provided on the lower surface of the flexible upper sheet 3 faces the fixed contact 6 provided on the upper surface of the lower sheet 5, and the spacer 7 is provided between both sheets 3 and 5. It is a switch element. Also, the membrane switch 2
A skirt-shaped side wall portion 8a that can be buckled and deformed is formed in a shape that supports the drive portion 8b, and a known click rubber 8 that causes a click feeling when the side wall portion 8a is buckled is placed on the top. The drive portion 8b of the click rubber 8 is located above the movable contact 4. Reference numeral 9 is a housing made of synthetic resin, and a guide wall 9a is erected on the housing 9, and an opening 9b inside the guide wall 9a is located above the drive portion 8b of the click rubber 8. The stem 11 projecting from the central portion of the rear surface of the synthetic resin key top 10 is inserted into the opening 9b so as to be slidable along the inner wall surface of the guide wall 9a. The key top 10 is supported by the click rubber 8 which is mounted on the drive portion 8b.

In the push button switch thus constructed, the operator resists the resilience of the click rubber 8 and the key top 10
When is pushed, the stem 11 descends along the inner wall surface of the guide wall 9a, and the drive portion 8b of the click rubber 8 is pushed downward by the stem 11. Then, when the driving portion 8b is lowered by a predetermined amount, the side wall portion 8a buckles, so that the reaction force that the key top 10 receives from the driving portion 8b suddenly decreases, and the click feeling is transmitted to the operator's finger. At the same time, the drive portion 8b is pushed into the membrane switch 2 and collides with the upper sheet 3 of the membrane switch 2, and as a result, the upper sheet 3 bends downward so that the movable contact 4 comes into contact with the fixed contact 6 and changes from OFF to ON. Switching is performed.

Further, when the operator removes the pressing operation force on the key top 10 in such an ON state, the buckled click rubber 8 returns to its original shape by its own elasticity, so that as the drive portion 8b rises. , The key top 10 is pushed up to the initial position via the stem 11, the bending of the upper sheet 3 is eliminated, and the movable contact 4 is fixed.
, And returns to the off state shown in FIG.

[0006]

By the way, recently, an information device equipped with a keyboard has become widespread, and it is not only necessary for the keyboard to simply function as an input device, but it is also friendly to an operator, that is, pressing force, stroke, There has been a demand for push button switches that are human-friendly and that are easy to use when the operator actually uses them, such as click feeling.

However, in the case of the above-mentioned conventional push button switch, the pressing force for pressing the key top 10 depends on the elastic force of the click rubber 8 for returning the key top 10 as it is, and the click force of the elastic force is small. Since the rubber 8 has a short life and does not buckle properly, it is difficult to provide a push button switch that functions with a comparatively light pressing force.

Further, in the case of the above-mentioned conventional push button switch, the elastic force and the size of the stroke at the time of overstroke after the movable contact 4 contacts the fixed contact 6 depend on the shape of the click rubber 8. Therefore, there is a problem that it is difficult to arbitrarily set these values.

The present invention has been made in view of the above problems of the prior art, and an object thereof is not only to reduce the pressing operation force of the key top, but also to prolong the service life and arbitrarily set the operation feeling. It is to provide a push button switch that can be operated.

[0010]

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, and by lowering the key top against the elastic force of the elastic member to switch the switch element, A link member having one end engaged with the housing and the other end engaged with the key top is provided, and an action piece for pressing the elastic member is provided on the link member, and the action piece is provided as the housing and the key top. It is achieved by positioning between the respective engaging portions with the link member.

Further, the above-mentioned object of the present invention is to hold a key top which is vertically movable above a housing, and is arranged below the key top to urge the key top upward and to click when buckling. The switch is provided with a click rubber that causes a feeling, and a switch element in which a movable contact pressed by the click rubber is opposed to a fixed contact, and the key top is pushed to cause the click rubber to buckle and deform. In a push button switch for switching elements, a pair of legs extending in parallel to each other are bridged by a first supporting portion, and a first link member provided with an action piece on the first supporting portion is parallel to the first link member. A second link member bridging a pair of leg pieces extending in the direction of a second support portion, and connecting the first link member and the second link member to each other. The leg pieces are rotatably connected so as to cross each other, and the first support portion is supported on one side of the back surface of the keytop and the second support portion is supported on the other side of the back surface of the keytop. , The engaging projections provided on the tip end portions of the leg pieces of the first and second link members are engaged with the housing, and the action piece is elastically contacted with the click rubber. .

[0012]

With the above structure, it is considered that the engaging portion between the housing and the link member is the fulcrum, the engaging portion between the key top and the link member is the force point, and the action piece provided on the link member is the action point. Therefore, the force required to be applied to the force point is less than the force required to press the key top, that is, the pressing force required to the action point.

Since the pressing distance of the elastic member can be shorter than the pressing distance of the key top, the elastic force of the click rubber can be increased and the height thereof can be lowered particularly when the click rubber is used as the elastic member. It is possible to use a stable click rubber having a long life.

In addition, when the operating piece is made to have elasticity, it is possible to push the key top against the elastic force of the elastic member and then further push the key top against the elasticity of the operating piece. As the elastic force of the action piece, an elastic force suitable for human sensitivity can be arbitrarily selected in addition to the elastic force of the elastic member.

[0015]

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.

However, the key top holding body 25 has the support shaft 28 of the outer link member 26 and the inner link member 2 attached thereto.
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 projections 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 protrusion 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 of the engaging protrusions 29a, 32a
Slide in the engagement recesses 22b and 22c, and are connected to each other by intersecting in a substantially X shape and the outer leg piece 29 and the inner leg piece 3.
2 gradually increases the angle of intersection as viewed from the side of the key top 23, and the operation piece 30 pushes the drive portion 24b of the click rubber 24 downwards accordingly, so that the drive portion 24
When b is lowered by a predetermined amount, the side wall portion 24a buckles and a click feeling is generated, and the driving portion 24b is pushed forcefully to collide with the upper sheet 17 of the membrane switch 16, and 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 this 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 tips of the inner leg pieces 32 of the inner link member 27 do not contact 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.

The key-top holder 25 used in the above-described embodiment has leg pieces 29 and 32 of both 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, and the turning radius of the tip of the operation piece 30 elastically contacting the top surface of the drive portion 24b is the key top. Since it is arranged so as to be about half of the turning radius of the support shaft 28 that is directly pushed into 23, the pushing amount of the driving portion 24b can be about half the pushing amount of the key top 23, and as a result, The amount of deformation of the click rubber 24 due to the operation is reduced, its life is extended, and high reliability can be maintained for a long time. And, again, the turning radius of the tip end of the action piece 30 as the action point is
Since the radius of rotation of the support shaft 28, which is the point of force, is about half, even if the pressing operation force applied to the support shaft 28 is small, a large force is exerted on the click rubber 24 by the action piece 30 by the lever principle. There is also an advantage that the pressing operation force can be reduced by pushing with. Moreover, in the above embodiment, the operating piece 30 itself is an elastic piece, and the operating 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 the operating piece 30 is an extremely thin push button switch. However, it is possible to reliably obtain an overstroke and expect a good operating feel.

Although the action piece is provided on the outer link member in the above embodiment, the action piece may be provided on the inner link member. Further, it goes without saying that the connecting structure of both link members, the supporting structure for the key top, the engaging structure for the housing, and the like can be appropriately selected.

FIG. 7 is a sectional view of the push button switch according to the second embodiment of the present invention, showing the OFF state. In FIG. 7, reference numeral 40 is a printed circuit board, and this printed circuit board 4
A fixed contact 41 is provided on the surface of 0, and a housing 42 made of synthetic resin and a known click rubber 43 are sequentially mounted on the printed circuit board 40. The movable contact 44 provided on the lower surface of the click rubber 43 and the fixed contact 41 face each other through an opening 42a provided in the housing 42, and these contacts 41 and 44 form a switch element. Further, reference numeral 45 is a housing 42.
A key top, which is held so as to be able to move up and down above, is a link member. Engagement protrusions 47 and 48 are provided at both ends of the link member 46, and an action piece 49 is provided in the central portion thereof, and the action piece 49 has some flexibility with respect to an external force in the plate thickness direction. Then, the engaging projection 47 at the upper end of the link member 46 is supported and fixed to the back surface of the key top 45,
The engaging projection 48 at the lower end is formed in the engaging recess 42b of the housing 42.
By slidably engaging the key top 45
Is assembled in the housing 42 via the link member 46, and in this assembled state, the tip end of the action piece 49 is always in elastic contact with the top surface of the click rubber 43.

Therefore, when the operator applies a pressing force to the key top 45 and pushes the key top 45, the link member 46 is gradually inclined in a direction in which the inclination angle is reduced, and accordingly, the action piece 49.
Pushes the top surface of the click rubber 43 downward, a click feeling is generated when the click rubber 43 is lowered by a predetermined amount, and the movable contact 44 is fixed by the fixed contact 4.
By touching 1, the switching from the off state to the on state is performed. In addition, when the operator removes the pressing operation force on the key top 45 in the ON state, the buckled click rubber 43 returns to its original shape by its own elasticity. 49 is pushed up, and thus the tilted link member 46 stands up, the key top 45 is pushed up to the initial position, and the movable contact 44 separates from the fixed contact 41 and returns to the off state.

[0032]

As described above, according to the present invention,
It is possible to provide a push button switch that requires only a small pressing force for pressing the key top and has a light touch and excellent operability. Further, since it is possible to reduce the distance to press the elastic member with respect to the distance to press the key top, especially when using click rubber as the elastic member,
A stable click rubber with a long life can be used,
The life of the push button switch can be extended and the reliability can be improved.
Further, in addition to the elastic force of the elastic member, the elastic force at the time of overstroke can be arbitrarily set, so that it is possible to provide a push button switch which is excellent in operation feeling and suitable for human sensitivity.

[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 cross-sectional view of a push button switch in an off state according to a second embodiment of the present invention.

FIG. 8 is a 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 25 Key Top Holder 26 (First) Link Member 27 (Second) Link Member 28 Support shaft (first support part) 29, 32 Leg pieces 29a, 32a Engagement protrusions 29b, 32b Crossing part 30 Working piece 31 Support shaft (second support part) 41 Movable contact 42 Housing 43 Click rubber 44 Fixed contact 45 Key top 46 Link member 47, 48 Engaging protrusion 49 Working piece

Claims (4)

[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 including a switch element, wherein the key top is lowered against the elastic force of the elastic member to switch the switch element, one end of which is engaged with the housing and the other end of which is A link member engaged with the key top is provided, and an action piece for pressing the elastic member is provided on the link member, and the action piece is provided between the housing and the engaging portions of the key top and the link member. Push button switch characterized by being positioned. 2. The push button switch according to claim 1, wherein
A push button switch in which the above-mentioned action piece has elasticity. 3. A key top that is held above and below the housing so as to be able to move up and down, and a click rubber that is arranged below the key top to urge the key top upward and to generate a click feeling when buckling. A switch element in which a movable contact pressed and driven by the click rubber is opposed to a fixed contact, and a push button switch in which the switch element is switched by pushing the key top to buckle and deform the click rubber. In, a pair of legs extending parallel to each other are bridged by a first support portion, and a first link member having an action piece provided on the first support portion and a pair of leg pieces extending parallel to each other are provided. A second link member bridged by two supporting parts,
The link member and the second link member are rotatably connected so that the leg pieces intersect each other, and the first support portion is supported on one side of the back surface of the key top, and the second support portion is also provided. To the other side of the back of the key top,
The engaging projections provided on the tip ends of the leg pieces of the first and second link members are engaged with the housing, and the action piece is elastically contacted with the click rubber. Push button switch. 4. The push button switch according to claim 3,
A push button switch, wherein the action piece has elasticity with respect to an external force in the plate thickness direction.