JP2006107986A - Membrane switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently attach a multiple key top of a membrane switch to a casing in one-touch operation. <P>SOLUTION: The multiple key top 50M is held to a holder 54 through interlocking rods 56. The holder 54 has a tube 54C press-fitted, to each stem-piercing part 16C of a casing 16 corresponding to the multiple key top 50M, and has, between the tube 54C of the holder 54 and the multiple key top 50M, an elastic sealing member 58 disposed by surrounding each corresponding stem 18 so as to seal the space between them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a membrane switch suitable for use in an input keyboard or the like of various information terminal devices such as a computer, and more particularly to a membrane switch having an improved mounting structure of a multiple key top.

  In general, this type of membrane switch includes a switch support member, a thin film circuit board including a contact point provided on the switch support member, a casing disposed so as to cover the thin film circuit board, and the casing. A stem that is penetrated and supported to advance and retract with respect to the thin film circuit board, and a leaf spring that is provided on the thin film circuit board and includes a pressing portion that is pressed by the stem and closes the contact portion of the thin film circuit board (patent) References 1 to 3).

  This type of membrane switch includes a plurality of key top groups including stems that pass through the housing and advance and retreat with respect to the respective contact portions of the thin film circuit board. The key top groups include at least two adjacent stems. Includes multiple key tops that move together.

  In order to hold the multiple key top in the casing, the membrane switch includes a holder having a plurality of cylindrical portions respectively surrounding each stem penetration portion of the casing corresponding to the multiple key top, and the holder and the multiple key top. An interlocking rod that is held by the holder between the key top and normally biases the multiple key top to the raised position is further provided.

  In the prior art, this holder is fixed to the housing by screwing, but in this structure, the holder is first screwed to the housing before assembling the holder, the multiple key top, and the interlocking rod. Then, since the interlocking rod and the multiple key tops have to be assembled sequentially, the assembly work is troublesome.

  In addition, if the inside of the multiple key top is left open, there is a disadvantage that dust and moisture enter the space where the contact pressing member such as a leaf spring is arranged through the stem penetration portion of the housing, and deteriorate the leaf spring. was there.

Japanese Utility Model Publication No. 3-387741 Japanese Utility Model Publication No. 3-387742 No. 7-343888

  The problem to be solved by the present invention is to provide a membrane switch that can be attached to the casing with a single touch without having to sequentially assemble the multiple key tops into the casing.

  Another problem to be solved by the present invention is to provide a membrane switch in which dust and moisture are prevented from entering from each stem of a multiple key top through a stem penetration part of a casing.

  The problem-solving means of the present invention includes a switch support member, a thin film circuit board including a plurality of contact portions provided on the switch support member, a casing disposed so as to cover the thin film circuit board, and the casing. A plurality of key top groups including a stem penetrating the body and moving forward and backward with respect to each contact portion of the thin film circuit board; and a corresponding contact portion of the thin film circuit board provided on the thin film circuit board and pressed by the stem. The key top group further includes a multiple key top holding means for holding the multiple key top in the housing. In the membrane switch, the multiple key top holding means includes a holder having a plurality of cylindrical portions that are held in the casing by being press-fitted into each stem penetration portion of the casing corresponding to the multiple key top. -An interlocking rod that is arranged between the multiple key top and controls the multiple key top to move up and down horizontally, and each corresponding to seal between the cylindrical portion of the holder and the multiple key top. It is an object of the present invention to provide a membrane switch comprising an elastic sealing member disposed so as to surround a stem.

  In the problem-solving means of the present invention, the holder and the multiple key top preferably have a locking portion for locking the interlocking rod in order to fix the interlocking rod, and in particular, at least one of the multiple key tops In the case of four or more multiple key tops, the four or more multiple key top interlocking bars are preferably composed of interlocking bar portions that intersect each other.

  According to the present invention, the holder that is disposed between the holder and the multiple key top and fixes the interlocking rod that urges the multiple key top to the raised position is not screwed to the casing, Because it is press-fitted into the stem penetration, this assembly can be assembled to the chassis with the holder, interlocking rod, and multiple key top assembled, making it possible to assemble membrane switches with multiple key tops. It can be done efficiently.

  In addition, since the inside of the multiple key top is closed by an elastic sealing member, dust and moisture do not enter the space where the contact pressing member is disposed through the stem penetration part of the housing, and the contact pressing member is The life of the switch can be extended without deterioration.

  An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an entire keyboard 40 including a membrane switch 10 according to the present invention. In the illustrated example, the keyboard 40 is a 1 described later. A single key top 50S that opens and closes one contact, a double key top 50T that opens and closes two contacts, and a multiple key top group 50MG that includes a four key top 50Q that opens and closes four contacts ( In the following description, multiple key tops are comprehensively displayed with reference numeral 50M). The single-acting key top 50S drives a single-acting switch unit 10U1 that opens and closes one contact, and the double and quadruple key tops 50T and 50Q drive a multiple-switch unit 10U2 that opens and closes one contact. The key tops 50S, 50T, and 50Q are all formed in a crown shape as shown in FIGS.

  2 and 3, the membrane switch 10 includes a switch support member 12, a thin film circuit board 14 including a contact portion (not shown) provided on the switch support member 12, and the thin film circuit board 14. A casing 16 disposed so as to cover, a stem 18 that penetrates the casing 16 and advances and retreats with respect to the thin film circuit board 14, and a thin film circuit board 14 that is provided on the thin film circuit board 14 and pressed by the stem 18 And a contact pressing member 22M such as a leaf spring 22 including a pressing portion 30 (see FIGS. 2B and 3B) for closing the contacts.

  Although not shown, the switch support member 12 is made of a conductive plate such as an iron plate in order to ground a part of the leaf spring 22 to the switch support member 12. The housing 16 and the stem 18 are made of plastic, and the leaf spring 22 is made of stainless steel or other appropriate metal material.

  The thin film circuit board 14 is pressed and held by the vertical plate wall 16VW of the housing 16 via the leaf spring 22 thereon. As shown in FIG. 1, the casing 16 has a cylindrical stem penetration portion 16C through which the stems 18 of the switch units 10U1 and 10U2 slidably pass. The stems 18 of the switch units 10U1 and 10U2 The space between the thin film circuit board 14 and the housing 16 is advanced and retracted for each switch unit 10U through the cylindrical stem penetration portion 16C.

  As shown in FIG. 2, the single-acting key top 50S of the single-acting switch unit 10U1 is integrally formed on the head of each corresponding stem 18, and as shown in FIGS. The multiple key tops 50T and 50Q of the unit 10U2 are integrally formed on the heads of the corresponding two stems 18, respectively.

  As shown in FIG. 2, the penetrating portion of the stem 18 normally biases the single-acting key top 50 </ b> S upward between the base portion 50 </ b> SB of the single-acting key top 50 </ b> S and the cylindrical stem penetrating portion 16 </ b> C of the housing 16. A rubber elastic sealing member 20 is attached to seal the. As can be seen from FIG. 2, the lower half portion 20LH of the elastic sealing member 20 has a small diameter so as to cover the small diameter portion 16CS of the cylindrical portion 16C of the housing 16, and the upper half portion 20UH is The diameter is larger than that of the lower half 20LH. This helps to allow the upper half 20UH to collapse around the lower half 20LH when the stem 18 is depressed (see FIG. 2B). Of course, the elastic sealing member 20 may have the same diameter over the entire length, and in this case, the elastic sealing member 20 is preferably a bellows, for example.

  As shown in FIGS. 3 and 5, the multiple membrane switch 10 </ b> U <b> 2 includes multiple key top holding means 52 that holds the multiple key top 50 </ b> M in the housing 16. The multiple key top holding means 52 includes a holder 54 held by the casing 16 and an interlocking rod 56 that holds the multiple key top 50M on the holder 54.

  The holder 54 includes a substrate 54B placed on the horizontal wall 16HW of the casing 16, and the substrate 54B is provided integrally with the substrate 54B corresponding to the stem penetration portion 16C of the casing 16, and has an outer peripheral surface on the stem penetration portion 16C. And a locking portion 54E for locking a part of the interlocking rod 56 (see FIGS. 6 and 7).

    As shown in FIGS. 5 and 6, the interlocking rod 56T for the double key top 50T is formed in a substantially U shape, and both end bent portions 56f are locked to the locking portions 54E of the holder 54, Further, the straight portion 56s parallel to the bent portion is locked to the locking portion 50E of the double key top 50T, and the double key top 50T moves up and down horizontally with respect to the holder 54 via the interlocking rod 56T. Controlled.

    As shown in FIGS. 5 and 7, the interlocking bar 56Q for the quadruple key top 50Q is formed by connecting two substantially U-shaped interlocking bar portions 56Q1 and 56Q2 so as to cross in a cross shape. The both ends bent portion 56f and the intermediate bent portion 56m are locked to the corresponding locking portions 54E of the holder 54, and both ends of the straight portion 56s crossing each other in a cross shape are the double key top 50T. The quadruple key top 50Q is controlled to move up and down horizontally with respect to the holder 54 through the interlocking rod 56T.

    Therefore, the multiple key top 50M is held by the holder 54 via the interlocking rod 56, and the holder 54 is press-fitted with the cylindrical portion 54C of the cylindrical stem penetrating portion 16C of the housing 16. The key top 56 </ b> M is held by the housing 16 via the interlocking rod 56 and the holder 54. When the cylindrical portion 54C of the holder 54 of the assembly 60 is press-fitted into the stem penetration portion 16C of the housing 16 in a state in which the multiple key top 50M, the interlocking rod 56, and the holder 54 are assembled, The assembly 60 is attached to the housing 16 with one touch so that the stem 18 penetrates the corresponding stem penetration portion 16 </ b> C of the housing 16.

    The multiple key top holding means 52 includes a rubber elastic sealing member 58 disposed so as to surround each corresponding stem 18 so as to seal between the cylindrical portion 54C of the holder 54 and the multiple key top 50M. In addition. The elastic sealing member 58 has substantially the same function as the elastic sealing member 20 of the single-acting switch unit 10U1, but, as shown in FIG. 3, the upper half portion fixed to the base portion 50MB of the multiple key top 50M. 58UH has a small diameter and the lower half portion 58LH has a large diameter, and the large diameter lower half portion 58LH is fixed to the upper end small diameter portion 54CE of the cylindrical portion 54C of the holder 54. Accordingly, when the multiple key top 50M is pushed down horizontally via the interlocking rod 56, the elastic sealing member 58 is folded so that the upper half 58UH enters the lower half 58LH.

    As shown in FIGS. 6 and 7, the multiple key top holding means 52 has guide claws 50 </ b> PW that hang down from the inner surface of the multiple key top 50 </ b> M, and these guide claws 50 </ b> PW are formed on the substrate 54 </ b> B of the holder 54. Is engaged with a guide piece 54G that rises from the upper side to guide the smooth raising and lowering of the multiple key top 50M.

  As shown in FIGS. 2, 3, and 4, the leaf spring 22 includes a plate frame 24 sandwiched between the thin film circuit board 14 and the vertical plate wall 16 </ b> VW of the housing 16, and one side 24 </ b> P of the plate frame 24. The extension piece 26 extends horizontally, and a free spring piece 28 extends in the direction opposite to the extension piece 26 from the tip of the extension piece 26 toward the one side 24P of the plate frame 24. The pressing portion 30 for closing the contact portion of the thin film circuit board 14 is provided at the base of the free spring piece 28, and the free spring piece 28 is inclined upward so as to face the lower surface of the stem 18, as shown in FIG. ing.

    In the illustrated form, the extension piece 26 of the leaf spring 22 is composed of a pair of parallel piece portions 26A and 26B and a connecting piece portion 26C for connecting the ends of the pair of parallel piece portions 26A and 26B. 28 extends from the connecting piece 26C.

  As shown in FIGS. 2 to 4, the plate frame 24 of the leaf spring 22 has a protrusion 24PR at the boundary between the adjacent switch units 10U, and the vertical wall plate 16VW of the housing 16 is connected to the plate frame 24. A groove 16G is provided at a position corresponding to the protrusion 24PR, and the protrusion 24PR of the leaf spring 22 is engaged with the groove 16G of the housing 16 so that the leaf spring 22 and the housing 16 are coupled to each other and positioned. Yes. In the illustrated embodiment, the leaf spring 22 is provided with the protrusion 24PR and the housing 16 is provided with the groove 16G, but conversely, the leaf spring 22 is provided with a groove and the housing 16 is provided with the protrusion, and these are mutually connected. The leaf spring 22 and the housing 16 may be coupled with each other and positioned.

  Next, the operation of the illustrated membrane switch 10 will be described. The keyboard 40 having the multi-unit membrane switch 10 is used, for example, as an input device of a computer. For each switch unit, the key top 50 is struck to obtain information. input. In a state where the key top 50 is not pushed down, as shown in FIG. 2A, the stem 18 is pushed up together with the single-acting key top 50S by the elasticity of the elastic sealing member 20, and as shown in FIG. The stem 18 is pushed up together with the multiple key top 50M by the elasticity of the elastic sealing member 58. This push-up position is set by engaging a shoulder portion 18S provided at the lower end of the stem 18 with a step portion 16S of the cylindrical portion 16C of the housing 16.

  When the key top 50 of a predetermined switch unit 10U1 or 10U2 is depressed to input information to the keyboard 40, the stem 18 is lowered while folding the elastic sealing members 20, 58. First, the lower end surface of the stem 18 is lowered. The upper end of the free spring piece 28 of the leaf spring 22 is engaged, and thereafter the stem 18 pushes down the free spring piece 28. When the free spring piece 28 of the leaf spring 22 is pushed down, the pressing portion 30 as its base presses the contact portion of the thin film circuit board 14 to close the contact.

  When the depression of the key top 50 is released, the stem 18 is raised by the restoring force of the leaf spring 22 and the restoring force of the elastic sealing member 20 or 58, and this rise is caused by the shoulder portion 18 </ b> S of the stem 18 penetrating the stem of the housing 16. Engage with the stepped portion 16S of the portion 16C and stop to prepare for the next depression.

  In the above-described embodiment, the stem 18 and the key top 50 are integrally formed. However, they may be formed separately and may be coupled by pressure fitting or other appropriate means.

  In the membrane switch of the present invention, the holder that holds the multiple key tops via the interlocking rod is not screwed to the casing, but is held by pressure fitting, so that it is not necessary to assemble these parts sequentially in the casing. With the multiple key tops, interlocking rods and holders assembled together, this assembly can be assembled to the housing with a single touch, thus simplifying the assembly work and enabling efficient assembly. Improves usability.

It is a top view of the keyboard which consists of a membrane switch concerning this invention. The single action switch unit of the membrane switch of this invention is shown, The figure (A) is the vertical sectional view before the depression, The figure (B) is the vertical sectional view after the depression. The multiple switch unit of the membrane switch of this invention is shown, The figure (A) is the vertical sectional view before the depression, The figure (B) is the vertical sectional view after the depression. A part of the leaf spring used in the present invention is shown, in which FIG. (A) is a plan view thereof and FIG. It is a disassembled perspective view of the keyboard using the membrane switch of this invention. The relationship between the single-acting key top for the double switch unit, the interlocking rod, and the holder is shown. FIG. (A) is a perspective view of the assembled state of the holder and the interlocking rod, and (B) in FIG. It is a perspective view of the back side of an assembly state with a key top. The relationship between the multiple key tops for the 4-unit switch unit, the interlocking rod and the holder is shown. FIG. (A) is a perspective view of the assembled state of the holder and the interlocking rod, and (B) in FIG. It is a perspective view of the back side of an assembly state with a key top.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Membrane switch 10U, 10U1, 10U2 Switch unit 12 Switch support member 12a Exposed part 14 Thin film circuit board 16 Case 16C Tube part 16CS Small diameter part 16S Step part 16G Groove 16VW Vertical board wall 18 Stem 18K Key top 18S Shoulder part 20 Elastic sealing Member 20LH Lower half part 20UH Upper half part 22 Leaf spring 22PW Claw 24 Plate frame 24PR Projection part 26 Extension piece 26A, 26B Parallel piece part 26C Connection piece 28 Free spring piece 30 Press part 40 Keyboard 50 Key top 50S Single action key top 50T Double key top 50Q Quad key top 50M Multiple key top 50MG Multiple key top group 52 Multiple key top holding means 54 Holder 54B Substrate 54C Cylindrical part 54CE Small diameter part 54E Locking part 56 Interlocking bar 56Q1, 56Q2 Interlocking bar Min 56f ends bent portion 56s straight portion 56m middle bent portion 58 resilient sealing member 58UH upper half 58LH lower half 60 assembly

Claims (3)

A switch supporting member; a thin film circuit board including a plurality of contact portions provided on the switch supporting member; a casing disposed to cover the thin film circuit board; and the thin film circuit penetrating the casing A plurality of key top groups each including a stem that advances and retracts with respect to each contact portion of the plate; and a pressing member that is provided on the thin film circuit board and is pressed by the stem to close the corresponding contact portion of the thin film circuit board. The key top group includes a multiple key top in which at least two adjacent stems are interlocked, and further includes multiple key top holding means for holding the multiple key top in the housing The multiple key top holding means is a holder having a plurality of cylindrical portions that are held in the casing by being press-fitted into each stem penetration portion of the casing corresponding to the multiple key top. An interlocking rod disposed between the holder and the multiple key top and controlling the multiple key top to move up and down horizontally, and sealing between the cylindrical portion of the holder and the multiple key top A membrane switch comprising an elastic sealing member disposed so as to surround each corresponding stem. 2. The membrane switch according to claim 1, wherein the holder and the multiple key top have a locking portion that locks the interlocking rod. 3. The membrane switch according to claim 1, wherein at least one of the multiple key tops is a four or more key key top, and the interlocking bar for the four or more key keys is A multiple key membrane switch characterized by consisting of interlocking rod parts that intersect each other.

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