JP2001184986A - Key board and key switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the disposition a shield plate between upper and lower plate members of a key board without requiring a change in the interconnection structure according to an increase in interval between both members. SOLUTION: A lower plate member 20 of a key board 10 comprises a plurality of protrusions 34 at a surface 20a opposite to a circuit plate assembly 18. The protrusions 34 at least support a plurality of switching contacts 16 of the circuit plate assembly 18. Between the lower plate 20 and the circuit plate assembly 18, there is disposed a shield plate as a static discharge measure on the surface 20a in such a manner that it is not overlapped with the protrusions. A thickness of the lower plate member is thinner than a height of the respective protrusions 34 that is protruded from the surface 20a. Thus, the protrusions 34 directly support the circuit plate assembly 18 by the flat top face 34a through a perforated hole 40 of the shield plate 38. For this reason, a gap is formed between the circuit plate assembly 18 and the shield plate 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a keyboard which is an input device of electronic equipment. Further, the present invention relates to a key switch used in such a keyboard.

[0002]

2. Description of the Related Art In a keyboard which is an input device of an electronic device such as a personal computer or a word processor, it is sometimes required to reduce the influence of electromagnetic noise on a mounted circuit. In particular, with a keyboard that can support an interface for high-speed data transmission, the transmission signal tends to pick up noise, so it is necessary to take measures to protect the transmission signal. 2. Description of the Related Art Conventionally, for example, as a measure against electrostatic discharge, it is known to install a shield plate that substantially covers a built-in circuit board inside a keyboard housing.

A keyboard as an input device is generally provided with a plurality of key tops, an upper plate member having a support structure for guiding and supporting the key tops so as to be able to move up and down, and a plurality of key tops arranged below the upper plate member. A circuit board assembly carrying switching contacts at respective lower positions; and a lower plate member (usually a lower housing of a keyboard) disposed below the circuit board assembly and connected to the upper plate member. Be composed. The individual key tops are based on the upper plate member of the keyboard, a dedicated support structure, a part of the circuit board assembly including the corresponding switching contacts, and an operating member that closes the switching contacts in conjunction with the downward movement of the key tops. And a component of the key switch composed of When a countermeasure against electrostatic discharge is applied to this keyboard, the shield plate is placed so as to overlap the upper or lower surface of the circuit board assembly.

In a key switch installed on a keyboard of this type, a support structure for supporting a key top above an upper plate member, that is, a base, extends downward from the key top and slidably engages with the base. An arrangement having a configuration cooperating with a sliding member is known. The sliding member is press-fitted at its upper end to the inner surface of the key top, and is slidably received at its lower portion by a sleeve portion erected on the base. A locking structure is provided between the base and the sliding member to prevent the sliding member from falling off the base.

[0005]

In the above-described conventional countermeasures against electrostatic discharge in a keyboard, since a shield plate is arranged on a circuit board assembly inside a keyboard housing, the thickness (height dimension) of the shield plate is reduced. ), The distance between the upper plate member and the lower plate member of the keyboard is enlarged. Therefore, in a portable electronic device in which a device housing including a keyboard is required to be as thin as possible, that is, as low as possible, there is a concern that the height of the keyboard may be increased by installing a shield plate. Also, the upper plate member and the lower plate member
They are connected to each other through a connection structure that can maintain a predetermined distance between them, but since the distance between them changes depending on the presence or absence of a shield plate, both keyboards that require electrostatic discharge countermeasures and those that do not need It is necessary to prepare a dedicated connection structure. When this connection structure is formed integrally with each of the upper plate member and the lower plate member, two types of molds must be manufactured in accordance with the presence or absence of the electrostatic discharge countermeasure,
As a result, there is a concern that noise reduction may increase keyboard manufacturing costs.

Further, in a key switch installed on a keyboard, it may be necessary to remove only the key top when replacing parts after assembling the key switch. In this case, in the conventional key switch having the above-described sliding member, it is possible to remove the keytop from the sliding member while the sliding member is connected to the base from the viewpoint of speeding up the operation. It is advantageous. However, in recent years, in order to reduce the friction between the sliding member and the sleeve portion of the base, an additive that enhances self-lubricating properties may be mixed into the material of the base and the sliding member. In that case, the pull-out force that tries to remove the key top from the sliding member,
The sliding member tends to be pulled out of the base first.

Accordingly, an object of the present invention is to increase the distance between an upper plate member and a lower plate member in a keyboard having an upper plate member and a lower plate member which are connected to each other by disposing a circuit board assembly therebetween. Without the necessity of changing the interconnection structure, a shield plate can be built in between the upper plate member and the lower plate member as a measure against electrostatic discharge of the circuit board assembly. An object of the present invention is to provide a keyboard capable of avoiding the increase.

Another object of the present invention is to provide a key switch having a sliding member attached to a keytop and slidably engaged with a base, wherein the keytop is kept connected to the base. It is an object of the present invention to provide a key switch which allows the key switch to be detached from the sliding member.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there are provided a plurality of key tops, an upper plate member having a support structure for supporting the key tops in a vertically movable manner, A circuit board assembly disposed below the upper plate member and carrying an open / close contact at a position below each of the plurality of key tops; and a lower plate member disposed below the circuit board assembly and coupled to the upper plate member Wherein the lower plate member has, on a surface facing the circuit board assembly, a plurality of raised portions that support at least the switching contacts of the circuit board assembly,
Between the lower plate member and the circuit board assembly, the shield plate is arranged so as not to overlap the plurality of ridges of the lower plate member,
A keyboard is provided.

In the above configuration, since the circuit board assembly is supported on the plurality of raised portions of the lower plate member, the distance between the upper plate member and the lower plate member is increased regardless of the presence or absence of the shield plate. It can be kept constant. Therefore, it is not necessary to change the configuration of the interconnection structure between the upper plate member and the lower plate member (particularly, the height dimension at the time of mutual fitting) depending on the presence or absence of the shield plate. That is, since it is not necessary to form a dedicated interconnecting structure in order to take measures against static electricity, it is possible to avoid an increase in keyboard manufacturing cost due to measures against electrostatic discharge.

According to a second aspect of the present invention, there is provided the keyboard according to the first aspect, wherein the shield plate has a plurality of through holes capable of receiving a plurality of raised portions of the lower plate member. According to this configuration, one shield plate that extends over substantially the entire circuit board assembly can be used.

[0012] The invention according to claim 3 is the invention according to claim 1 or 2.
2. The keyboard according to claim 1, wherein the thickness of the shield plate is smaller than the height of the raised portion on the surface of the lower plate member. According to this configuration, since a gap is formed between the circuit board assembly and the shield plate, for example, liquid that has inadvertently entered between the upper plate member and the lower plate member is positively applied to the gap. The inflow can prevent the liquid from penetrating the circuit board assembly.

According to a fourth aspect of the present invention, in the keyboard according to any one of the first to third aspects, the keyboard is disposed between a plurality of key tops and a circuit board assembly, and each of the key tops is lowered. There is further provided a keyboard further comprising a plurality of actuating members for closing the on-off contact in conjunction with the operation, wherein the plurality of raised portions of the lower plate member respectively support the plurality of actuating members via the circuit board assembly. According to this configuration, the force applied to the circuit board assembly from the operating member can be reliably received by the plurality of raised portions of the lower plate member.

According to a fifth aspect of the present invention, there is provided a base, and a key top arranged on the base so as to be movable in an elevating direction.
A support structure for guiding and supporting the key top in the elevating direction on the base, wherein the support structure includes a sliding member attached to the key top and slidably engaged with the base. A locking structure is provided between the base and the sliding member to prevent the sliding member from falling off the base, and the locking structure is fixed at the base end to either the sliding member or the base. And a resilient arm having a hook at the distal end for engaging the other of the sliding member and the base, the hook having an inclined engaging surface extending at an acute angle outward with respect to the resilient arm. Provide a key switch.

In the above configuration, when the key top is subjected to an upward pulling force when the key top is removed from the sliding member for replacement of a part or the like, the elastic arm bends and the inclined engagement surface of the hook becomes a shoulder. Since the sliding member is in surface contact with the surface, the sliding member is locked and held in the sleeve portion against the pulling force. If the holding force by the inclined engagement surface is made larger than the mounting force between the key top and the sliding member, the key top can be removed from the sliding member while the sliding member is held in the sleeve portion. become able to.

According to a sixth aspect of the present invention, there is provided a keyboard configured by arranging a large number of the key switches according to the fifth aspect. With such a keyboard, operations such as replacing parts after assembling the key switch are extremely easy.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the drawings, the same or similar components are denoted by common reference numerals. Referring to the drawings, FIG. 1 is an exploded perspective view of a main part of a keyboard 10 according to an embodiment of the present invention, and FIG.
FIG. 4 is a cross-sectional view at the time of assembly. The keyboard 10 includes a plurality of key tops 12, an upper plate member 14 having a support structure for supporting the key tops 12 in a vertically movable manner, and an upper plate member 14.
, And a circuit board assembly 18 carrying an open / close contact (ie, a contact pair) 16 at a position below each of the plurality of key tops 12, and an upper plate member 14 arranged below the circuit board assembly 18. And a lower plate member 20 connected to the lower plate member 20.

The plurality of key tops 12 are keying operation members having truncated quadrangular pyramids and various shapes and dimensions. The upper plate member 14 corresponds to the required configuration of the keyboard 10.
Are arranged according to a predetermined arrangement. Each key top 12 has an inner surface 12b opposite to the keying operation surface 12a.
And a sliding member 22 slidably engaged with the upper plate member 14. The sliding member 22 is press-fitted to the inner surface 12b of the key top 12 at its upper end 22a, and is slidable on a corresponding sleeve portion 24 erected on the upper plate member 14 at its columnar lower portion 22b. Accepted.

The upper plate member 14 is provided with a plurality of tubular sleeve portions 24 standing upright on the main surface 14a thereof in an arrangement corresponding to a predetermined arrangement of the plurality of key tops 12. The sleeve portions 24 are preferably provided on the upper plate member 14.
Through hole 2 formed integrally with the upper plate member 14
4a is defined for each. Each sleeve portion 24 receives the lower portion 22b of the sliding member 22 attached to the corresponding key top 12 in an axially slidable manner with substantially no play, and cooperates with each sliding member 22. The key top 12 is guided and supported on the upper plate member 14 in the elevating direction. Therefore, the key top 12 moves the operation surface 12a substantially parallel to the main surface 14a in a substantially vertical direction with respect to the upper plate member 14 under the mutual guiding action of the sleeve portion 24 and the sliding member 22 as the support structure. The parallel movement is performed while maintaining the predetermined substantially horizontal posture.

The circuit board assembly 18 includes a plurality of key tops 1.
2 and a pair of sheet substrates 26 each carrying a plurality of contacts 16a in an arrangement corresponding to the two arrangements, and a sheet-like sheet disposed between the sheet substrates 26 and having openings 28a at positions corresponding to the plurality of contacts 16a. And a spacer 28. Each of the pair of sheet substrates 26 has a configuration of a well-known flexible printed circuit board, and a plurality of contacts 16a are provided on the surface of each film substrate. The two sheet substrates 26 are superimposed on the spacer 28 with their corresponding contacts 16a facing each other and the contacts 16a being aligned with the openings 28a.
The spacer 28 supports the two sheet substrates 26 at a predetermined interval, and a plurality of pairs of contacts 16a (open / close contacts 1) facing each other.
6) is kept open. The circuit board assembly 18 is positioned below the upper plate member 14 so that the switching contacts 16 are aligned with the respective centers of the plurality of through-holes 24a of the upper plate member 14 so as to be positioned on the lower plate member 20 as described later. Supported.

The keyboard 10 further includes a plurality of actuating members 30 disposed between the plurality of keytops 12 and the circuit board assembly 18. Each operating member 30 is a key top 1
In conjunction with the lowering operation of each of the two, the elastic member itself elastically deforms and acts to close the corresponding on-off contact 16 on the circuit board assembly 18. Each operating member 30 is a dome-shaped member integrally formed from a rubber material, and is positioned below each through-hole 24a of the upper plate member 14 in a posture in which the dome top 30a faces the key top 12 side. Placed. Thereby, the dome top 30a of each operating member 30 is on its top surface,
Each key top 12 received in each sleeve portion 24 of the upper plate member 14 comes into contact with the lower end surface of the sliding member 22. On the back side of the dome top 30a of each operating member 30, a columnar pressing portion 30b extending toward the circuit board assembly 18 is formed. Each operating member 30 presses the pressing portion 30b when there is no load,
Positionally aligned with the switching contact 16 of the circuit board assembly 18,
In addition, it is arranged to be separated upward from the upper sheet substrate 26.

Each of the switching contacts 16 carried by the circuit board assembly 18 is normally held open via a spacer 28 by a pair of sheet substrates 26 essentially having a strainer. The circuit board assembly 1 is mounted on the dome top 30a of the operating member 30.
When an external force is applied in the direction approaching 8, the operating member 30 is elastically deformed, and the pressing portion 30b presses the upper sheet substrate 26 from the outer surface, thereby closing the on-off contact 16. In the illustrated embodiment, a plurality of actuating members 30 are fixedly and integrally formed with flexible sheet members 32 disposed between the upper plate member 14 and the circuit board assembly 18 at the lower end of the dome opening. Are linked together. Note that each operating member 30 can be directly connected to the upper sheet substrate 26 of the circuit board assembly 18 without using the sheet member 32.

When no external force is applied to the key tops 12 at the time of keying operation of each key top 12, the operating member 30
Is the top surface of the dome top 30a, and biases and supports the key top 12 to the upper limit vertically away from the main surface 14a of the upper plate member 14 via the sliding member 22. At this time, the switching contact 16 of the circuit board assembly 18 is in an open state. Also,
When the keytop 12 is pressed down by a keying operation of the operator, the operating member 30 is deformed while applying an upward elastic biasing force to the keytop 12, and the pressing member 30 b is moved upward by the pressing portion 30 b immediately before the keytop 12 reaches the lower limit position. The open / close contact 16 is closed by pressing the sheet substrate 26 from the outer surface. When the pressing force on the keytop 12 is released, the operating member 30 is elastically restored, the keytop 12 is returned to the upper limit position, the upper sheet substrate 26 is restored, and the switching contact 16 is opened.

The lower plate member 20 of the keyboard 10 is formed as a lower housing of the keyboard 10 in the illustrated embodiment.
It is assembled to an upper housing (not shown) arranged on the upper plate member 14. Alternatively, the upper plate member 14 is
Can be configured as an upper housing. Lower plate member 20
The circuit board assembly 18 is provided with a plurality of raised portions 34 on its surface 20a facing the circuit board assembly 18 for supporting at least the plurality of switching contacts 16 of the circuit board assembly 18. The ridges 34 are integrally formed on the lower plate member 20 in an arrangement corresponding to the arrangement of the plurality of key tops 12, so that a recess 36 having the surface 20a as a bottom surface is formed around each ridge 34. Is done. The lower plate member 20 is formed such that the overall thickness (height dimension) of each raised portion 34 is substantially the same as the thickness of the lower housing of a conventional general keyboard.

The keyboard 10 further includes a circuit board assembly 1
8 is provided with a shield plate 38 disposed between the lower plate member 20 and the circuit board assembly 18. The shield plate 38 is placed on the surface 20 a of the lower plate member 20 so as not to overlap the plurality of raised portions 34 of the lower plate member 20. In the illustrated embodiment, the shield plate 38 includes a plurality of through holes 40 that can individually receive the plurality of ridges 34.
The through-holes 40 receive the raised portions 34 and are arranged so as to cover almost the entire surface 20 a of the lower plate member 20. The shield plate 38 can be formed of, for example, a metal plate of aluminum, copper, or the like, or a plastic plate having a conductive film coated on the entire surface.
, The electrostatic discharge of the signal circuits on the pair of sheet substrates 26 is prevented. Instead of one shield plate 38, a plurality of small shield plates may be used in parallel.

In the illustrated embodiment, the thickness of the shield plate 38 is determined by the thickness of each raised portion 3 protruding from the surface 20 a of the lower plate member 20.
4 is smaller than the protruding height. As a result, the plurality of raised portions 34 protrude above the shield plate 38 through the through holes 40 of the shield plate 38, and each of the substantially flat top surfaces 3.
4a directly supports the circuit board assembly 18. More specifically, each raised portion 34 abuts on the outer surface of the sheet substrate 26 below the circuit board assembly 18 at its top surface 34a to support the corresponding contact 16a and its peripheral portion, and A corresponding dome opening end of the operating member 30 is supported via the plate assembly 18. Accordingly, the lower plate member 20 receives the elastic force applied to the circuit board assembly 18 from the key top 12 via the operating member 30 at the time of the keying operation of each key top 12 at each of the plurality of raised portions 34, The operating member 30 can receive a pressing force when the switching contact 16 of the circuit board assembly 18 is closed. In a normal state, the circuit board assembly 18 itself has a substantially flat shape on the plurality of raised portions 34 due to the stiffness of the circuit board assembly 18, so that a gap between the circuit board assembly 18 and the shield plate 38 is maintained. Is formed.

The upper plate member 14 and the lower plate member 20 are connected to each other via a connection structure capable of maintaining a predetermined interval therebetween. The connection structure includes a plurality of upper fitting portions 42 that are integrally provided on the back surface 14b of the upper plate member 14 at positions separated from the plurality of sleeve portions 24, and corresponding to the upper fitting portions 42, The lower plate member 2 is located at a position away from the plurality of raised portions 34.
A plurality of lower fitting portions 4 which are integrally erected on the surface 20a of the
And 4. The upper plate member 14 and the lower plate member 20 are elastically inserted by inserting the claw portion 42a at the free end of each upper fitting portion 42 into the claw portion 44a at the free end of each lower fitting portion 44 at a corresponding position from above. By being engaged with each other, they are connected to each other at a predetermined interval. The circuit board assembly 18, the sheet member 32, and the shield plate 38 are respectively provided with holes 46, 48, 50 through which the plurality of lower fitting portions 44 of the lower plate member 20 penetrate.

In the keyboard 10 having the above-described structure, the lower plate member 20 is configured to have the same overall thickness as the thickness of the lower housing of the conventional general keyboard at each of the raised portions 34, Plate assembly 18 and lower plate member 2
Since the shield plate 38 is arranged so as not to overlap with each of the raised portions 34 between 0 and 0, measures against electrostatic discharge can be taken without increasing the height of the keyboard 10. In addition, the circuit board assembly 18 includes the plurality of raised portions 3 of the lower plate member 20.
Since it is directly supported on the upper surface 4, the distance between the upper plate member 14 and the lower plate member 20 can be kept constant regardless of the presence or absence of the shield plate 38. Therefore, the upper plate member 1
Upper fitting portion 42 which is an interconnected structure between the lower plate member 4 and the lower plate member 20.
And the configuration of the lower fitting portion 44 (particularly, the height dimension at the time of mutual fitting)
Need not be changed depending on the presence or absence of the shield plate 38. That is, by simply removing the shield plate 38 from the keyboard 10 on which the countermeasures against electrostatic discharge have been taken, the key tops 12,
By using the upper plate member 14, the circuit board assembly 18, and the lower plate member 20 as shared components, a keyboard that does not require measures against electrostatic discharge can be configured. Thus, according to the keyboard 10,
Since it is not necessary to form the dedicated upper plate member 14 and lower plate member 20 in order to take measures against static electricity, it is possible to avoid an increase in the manufacturing cost of the keyboard 10 due to measures against electrostatic discharge.

Further, in the keyboard 10, the shield plate 3
The thickness of each raised portion 3 from the surface 20a of the lower plate member 20
4 so that a gap is formed between the circuit board assembly 18 and the shield plate 38. For example, the upper plate member 14 and the lower plate member 20 are inadvertently inadvertently formed.
And the liquid that has entered between them can positively flow into this gap. As a result, the liquid is
Can be prevented from penetrating into the switch contact 16.

In the keyboard 10 described above, each of the plurality of key tops 12 is based on the upper plate member 14 and has a dedicated support structure (sleeve portion 24 and a sliding member 22 cooperating therewith) with a corresponding open / close contact. The key switch 52 is a component of the key switch 52 that includes a part of the circuit board assembly 18 including the key 16 and the operating member 30 that closes the switching contact 16 in conjunction with the lowering operation of each key top 12. Therefore, the keyboard 10 can be defined as a configuration including a plurality of such key switches 52 in a predetermined arrangement. Here, each key switch 52 of the keyboard 10 is
The supporting structure, which is one of the constituent elements, is not limited to the sliding structure described above, and may be constituted by a pair of link members that guide and support the key top 12 on the base 14 in the elevating direction. As such a pair of link members,
One that is combined in an X shape in side view and rotatably connected to each other at an intersection (for example, see Japanese Utility Model Application Laid-Open No. 5-66832), and is combined in an X shape in side view and slidably connected to each other at the intersection. (See, for example, Japanese Patent Application Laid-Open No. 9-27235), those which are combined in an inverted V-shape in side view and are rotatably connected to each other at one end in a gear shape (for example, Japanese Patent Application Laid-Open No.
-3628) and the like.

FIG. 3 shows a key switch 60 according to another embodiment of the present invention which can be used in the keyboard 10 described above. The key switch 60 has substantially the same configuration as the above-described key switch 52 except for the configuration of the key top and the sliding member. Therefore, the corresponding components are denoted by the same reference numerals and the description thereof is omitted. I do.

The key switch 60 includes a base (upper plate member 1).
4) Key top 6 arranged on the upper side so as to be movable in the elevating direction
2 and a support structure for guiding and supporting the key top 62 in a sliding manner on the base in the elevating direction. The support structure includes a hollow columnar sleeve portion 24 erected on the base and a sliding member 64 provided on the inner surface 62 a of the key top 62. The sliding member 64 is press-fitted to the inner surface 62a of the key top 62 with an overhanging upper portion 64a,
The hollow sleeve lower portion 64b is slidably received in the corresponding sleeve portion 24. The sleeve part 24 is a key top 6
2, the lower portion 64b of the sliding member 64 is slidably received in the axial direction substantially without play, and in cooperation with each sliding member 64, the key top 62 is moved upward and downward on the base. Guide support.

On the inner surface 62a of the key top 62, a pair of press-in pieces 66 are erected substantially at the center thereof, and a plurality of sets of guide pieces 68 are erected so as to surround the press-in pieces 66. The pair of press-fitting pieces 66 are press-fitted into recesses 70 provided on the end surface of the upper portion 64a of the sliding member 64, and fix the key top 62 and the sliding member 64 to each other against an external force (pulling force). connect. The plurality of guide pieces 68 engage with the outer peripheral surface of the upper portion 64a of the sliding member 64, and
When the two are attached to the sliding member 64, they act to guide the two relatively to a predetermined position. The key top 62 is usually attached from above to a sliding member 64 previously mounted on the sleeve portion 24. At this time, it may be difficult to visually check the inner surface 62a of the key top 62. Even in such a case, the key top 62 can be easily attached to the sliding member 64 by the action of the plural sets of guide pieces 68. This is particularly advantageous when the key top 62 has a larger dimension as compared to the sliding member 64 as shown.

A locking structure is provided between the sleeve 24 and the sliding member 64 to prevent the sliding member 64 from falling off the sleeve 24. The locking structure includes a pair of elastic arms 72 (only one elastic arm 72 is shown) provided at mutually opposing positions of the lower portion 64b of the sliding member 64, and the sleeve portion 2
And a pair of shoulder surfaces 74 provided downward at mutually opposing positions on the inner surface of the inner surface 4. Each elastic arm 72 includes a sliding member 6.
4 extends axially as a part of the lower portion 64b, is fixedly and integrally connected at its proximal end to the lower portion 64b, and has an outwardly projecting hook 76 at its free end. Have. The sleeve 24
A groove 78 is provided on the inner surface of each of the grooves so as to extend downward in the axial direction adjacent to each shoulder surface 74.

When the sliding member 64 is mounted on the sleeve portion 24, the tapered outer surfaces 76a (FIG. 4) of the hooks 76 of the pair of elastic arms 72 are pressed against the upper edge 24b of the sleeve portion 24, and While elastically bending the elastic arm 72 radially inward, the lower portion 64b of the sliding member 64 is
4 inside. Then, the hook 7 of the both elastic arms 72
At the point in time when 6 has passed over both shoulder surfaces 74 of the sleeve portion 24, the two elastic arms 72 are elastically restored outward in the radial direction. In this state, the hooks 76 of each elastic arm 72 of the sliding member 64 are
Are slidably received in grooves 78 provided adjacent to each shoulder surface 74. As a result, the sliding member 64 is
Under the mutual guiding action of the hooks 76 and the grooves 78, the upper limit position where each hook 76 engages with each shoulder surface 74, and the overhanging upper portion 64 a engages with the upper end surface of the sleeve portion 24. To the lower limit position.

In the key switch 60, the lower end surface of the lower portion 64b of the sliding member 64 to which the key top 62 is attached is
It comes into contact with the top surface of the dome top 30a of the operating member 30 shown in FIG. When an external force is not applied to the key top 62 during the keying operation, the operating member 30 moves the key top 62 to the upper limit position via the sliding member 64 (the upper limit position of the sliding member 64).
To support. When the keytop 62 is depressed by an operator's keying operation, the operating member 30 is deformed while exerting an upward elastic biasing force on the keytop 62, and the keytop 62 is moved to the lower limit position (the lower limit position of the sliding member 64). Immediately before reaching, the upper sheet substrate 26 shown in FIG. When the pressing force on the keytop 62 is released, the operating member 30 is elastically restored, the keytop 62 is returned to the upper limit position, and the switching contact 16 is opened.

As shown schematically in FIG. 4, as shown in FIG.
The hook 76 provided on each elastic arm 72 of FIG. 4 has a cushioning surface 76b that extends as an engaging surface engaging with each shoulder surface 74 at an obtuse angle outward from the outer surface 72a of the elastic arm 72, An inclined engaging surface 76c extending outwardly from the surface 76b in a direction forming an acute angle with respect to the outer surface 72a. Each hook 76
Of the sliding member 64 during the keying operation described above.
When reaches the upper limit position in the sleeve portion 24, it first contacts the intersection corner portion 74a between the inner surface of the sleeve portion 24 and each shoulder surface 74 (FIG. 4A). At this time, the buffer surface 76b
Extend outwardly from the outer surface 72a of the elastic arm 72 at an obtuse angle, so that it is pressed radially inward by the crossing corner 74a under the upward elastic biasing force of the operating member 30. The elastic arm 72 flexes slightly inside the sliding member 64. As a result, the impact when each hook 76 is engaged with each shoulder surface 74 is reduced, and the collision sound is effectively reduced.

The inclined engagement surface 76c of each hook 76 is usually
When the sliding member 64 is at the upper limit position in the sleeve portion 24, the sleeve portion 24 is
On each shoulder surface 74. In this state, the sliding member 64
It is locked and held at the upper limit position under the elastic biasing force of the operating member 30. On the other hand, when an upward external force such as pulling out from the sleeve portion 24 is applied to the sliding member 64, the cushioning surface 76 b of each hook 76 is further pressed radially inward by the intersection corner portion 74 a of each shoulder surface 74, and each elastic member The arm 72 is largely bent inside the sliding member 64. As a result, the inclined engaging surface 76c of each hook 76 abuts in parallel with each shoulder surface 74, and the sliding member 64 is inserted into the sleeve portion 24 against external force due to relatively large frictional force due to mutual surface contact. Locked and held (Fig. 4
(B)).

According to the key switch 60 having the above-described configuration, the key top 62 is moved to the sliding member 64 for parts replacement or the like.
When an upward pulling force is applied to the key top 62 when the key top 62 is detached from the key arm 62, the sliding member 64 causes the inclined engagement surface 76 c of the hook 76 of each of the elastic arms 72 to move as shown in FIG.
4 is in surface contact with both shoulder surfaces 74, so that it is locked and held in the sleeve portion 24 against the pull-out force. This inclined engagement surface 76
The holding force by c can be easily increased more than the holding force of the press-fitting piece 66 of the key top 62 in the recess 70 of the sliding member 64. As a result, the key top 62 can be detached from the sliding member 64 while the sliding member 64 is held in the sleeve portion 24 by the pulling force applied to the key top 62.

The key switch 60 has a pair of elastic arms 72 on the sleeve 24 on the base side and a pair of shoulder surfaces 74 on the sliding member 64, as shown in a modified example in FIG.
(Only one shoulder surface 74 is shown). In the illustrated example, the lower portion 64 of the sliding member 64
b is configured such that the sleeve portion 24 can be slidably received therein. Therefore, the sleeve portion 24 is configured by providing a hook 76 projecting outwardly on each of a pair of elastic arms 72 extending in the axial direction at mutually opposing positions as part of the cylindrical wall. In addition, a pair of shoulder surfaces 74 formed upward at opposing positions and a groove 78 extending upward in the axial direction adjacent to each shoulder surface 74 are provided on the inner surface of the lower portion 64 b of the sliding member 64. . Alternatively, although not shown, an elastic arm having an inward hook is provided in the sleeve portion 24 in the configuration of FIG. 3, or an elastic arm having an inward hook is provided in the lower portion 64b of the sliding member 64 in the configuration of FIG. You can also. It will be understood that the same operation and effect as those described above can be achieved by any of the configurations.

[0041]

As is apparent from the above description, according to the present invention, in a keyboard having an upper plate member and a lower plate member which are connected to each other by disposing a circuit board assembly therebetween, It is possible to incorporate a shield plate between the upper plate member and the lower plate member as a countermeasure against electrostatic discharge of the circuit board assembly without requiring a change in the interconnection structure due to an increase in the distance between the lower plate member and the lower plate member. Will be possible. Therefore, according to the present invention, it is possible to avoid an increase in the manufacturing cost of the keyboard caused by taking measures against noise.

Further, according to the present invention, in a key switch having a sliding member attached to a keytop and slidably engaged with a base, the keytop can be removed while the sliding member is still connected to the base. It becomes possible to remove it from the sliding member. Therefore, according to the present invention, it is possible to speed up operations such as component replacement after key switch assembly.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part of a keyboard according to an embodiment of the present invention.

FIG. 2 is a sectional view of the keyboard of FIG. 1;

FIG. 3 is an exploded perspective view showing a main part of a key switch according to another embodiment of the present invention.

4A and 4B are explanatory diagrams of the operation of the locking structure in the key switch of FIG. 3, schematically showing (a) the upper limit position of the sliding member and (b) each state when the sliding member is locked.

FIG. 5 is an exploded perspective view of a modification of the key switch of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Keyboard 12, 62 ... Key top 14 ... Upper plate member (base) 16 ... Opening / closing contact 18 ... Circuit board assembly 20 ... Lower plate member 22, 64 ... Sliding member 24 ... Sleeve part 30 ... Operating member 34 ... Protrusion Part 38 Shield plate 40 Through hole 42 Upper fitting part 44 Lower fitting part 52, 60 Key switch 72 Elastic arm 74 Shoulder surface 76 Hook 76c Slant engagement surface

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Tanaka 2-3-5 Higashi Gotanda, Shinagawa-ku, Tokyo F-term Takamizawa Component Co., Ltd. F term (reference) 5B020 DD02 DD15 DD25 DD51 5G006 AA01 BA01 BB03 CB01 CD02 CD07 FB05 FB14 LB03

Claims (6)

[Claims] A plurality of key tops; an upper plate member having a support structure for supporting the key tops so as to be able to move up and down; and an upper plate member disposed below the upper plate member and provided at a lower position of each of the plurality of key tops. A keyboard comprising: a circuit board assembly that carries an open / close contact; and a lower board member disposed below the circuit board assembly and connected to the upper board member. On the surface facing the solid,
The circuit board assembly has a plurality of raised portions that support at least the switching contacts, and between the lower plate member and the circuit board assembly, does not overlap the plurality of raised portions of the lower plate member. A keyboard is provided on the keyboard. 2. The keyboard according to claim 1, wherein the shield plate has a plurality of through holes capable of receiving the plurality of raised portions of the lower plate member. 3. The keyboard according to claim 1, wherein a thickness of the shield plate is smaller than a height of the raised portion on the surface of the lower plate member. 4. The apparatus according to claim 1, further comprising a plurality of operating members disposed between the plurality of key tops and the circuit board assembly, the plurality of operating members closing the on / off contact in conjunction with a lowering operation of each of the key tops. The keyboard according to any one of claims 1 to 3, wherein the plurality of raised portions of the lower plate member respectively support the plurality of operating members via the circuit board assembly. 5. A base comprising: a base; a key top arranged on the base so as to be movable in a vertical direction; and a support structure for guiding and supporting the key top on the base in a vertical direction, wherein the support structure is provided. A key switch comprising a sliding member attached to the key top and slidably engaging the base, wherein the sliding from the base is between the base and the sliding member. A locking structure for preventing a member from falling off is provided, and the locking structure is fixed to one of the sliding member and the base at a proximal end, and the other of the sliding member and the base at a distal end. A key switch, comprising: a resilient arm having a hook engaged with the resilient arm, the hook having an inclined engaging surface extending outwardly at an acute angle with respect to the resilient arm. 6. A keyboard constituted by arranging a large number of key switches according to claim 5.