KR101301980B1 - Tact switches - Google Patents

Abstract

PURPOSE: A tact switch is provided to prevent water from flowing into a contact point by attaching a waterproof film. CONSTITUTION: A tact switch includes a housing (105), a contact dome, a stem (107), a hole, a push lever (109), and a cover. In the bottom of the housing, a base part (103) is formed. In the base part, lead pieces (102) are disposed so that internal terminals (101) can be exposed. The contact dome is disposed on the internal terminals, and is prepared on a sheet formed in the housing base part. The stem electrically connects the lead pieces. The hole is formed in the central part of the stem. The push lever is inserted into the hole. The cover seals the upper part of the housing. A waterproof film is attached to the contact dome and the upper surface of the base part. A film cover is disposed in the upper part of the stem and the inner side of the cover. A peripheral part (124) is elastically disposed in the inclined outer side of the stem.

Description

Tact Switch {TACT SWITCHES}

The present invention relates to a tact switch having a plurality of open / close circuits, and more particularly to a tact switch having improved waterproof characteristics and structural stability.

Home appliances require a plurality of switch buttons to perform various functions, and because of this, the control panel panel has a complex and large area, and thus a plurality of switches can be used as a single switch for compactness, light weight, and ease of use. A multi-directional tact switch is used to perform the switching function.

As an example of such a multi-directional tact switch, the multi-directional tact switch disclosed in Korean Utility Model Registration No. 20-0366309 (notified on November 04, 2004) has a base as shown in FIG. The metal dome 20 for electrically connecting or insulating the terminals between the plurality of contact terminals 12 and 14 is disposed in the housing 11 of the 10, respectively, and the terminal 15 as a lead piece is externally disposed. An inner stem 30, a four-way crimp 43 and an inner stem which are disposed to be exposed and which can press the metal dome 20 to selectively press the contact terminals 12 and 14 to perform a switching operation. And an outer stem 40 and a cover 50 provided with a stem tube 41 that is movable in association with the cover 50.

However, when the conventional tact switch is used in a home appliance using water such as a washing machine or a product exposed to a humid environment, moisture may penetrate the contact, and in this case, the circuit damage due to the short may be prevented. There was a problem caused.

In addition, during the soldering process for mounting such tact switches on a circuit board, flux or molten solder is flowed back along the lead piece and flows between the stem and the cover, resulting in a problem of malfunction.

Domestic Utility Model Registration No. 20-0366309 (announced on November 04, 2004)

The present invention is to solve the problems of the conventional tact switch, it is an object of the present invention to provide a tact switch having improved waterproof properties to prevent the inflow of moisture from the outside to the contact point.

It is also an object of the present invention to provide a tact switch having an improved structure which prevents a malfunction of the stem due to flux or molten solder that flows back during the soldering process for mounting the tact switches to the circuit board.

In order to achieve the above object, a tact switch according to the present invention includes a housing in which a base portion on which a plurality of lead pieces are arranged is exposed to expose a plurality of internal terminals forming a contact, and a housing base on each of the internal terminals. A conductive metal contact dome disposed on a sheet formed in the portion, a stem selectively pressing the respective contact domes to electrically connect the lead pieces, and fitted into a hole formed in the center of the stem to push a user for switching operation A tact switch having a lever and a cover for sealing an upper portion of the housing,

The upper surface of the base portion is entirely covered by an adhesive with an outer contour that is entirely in line with the contour of the inner wall of the housing to keep the contact domes in place in the seat and prevent moisture from penetrating into the contact domes. It is attached to the contact and the dome.

Further, it is preferable that the bottom portion is integrally formed by injection molding on the bottom side of the base provided in the housing so as to prevent water from flowing through the terminal fixing portion from the bottom side of the tact switch.

An elastic film cover having a hole formed to penetrate the stem is provided on the upper side of the stem and on the inner side of the cover, and the inner periphery of the film cover is inclined outside of the stem so that the elastic force acts downward on the stem. It is preferable to arrange | position it in the elastically curved state at the side surface.

When the flange is formed on the cover, and the flange is bent to assemble the cover to the housing, the hook is preferably fastened through a fastening groove formed in the flange to securely assemble the cover in close contact with the housing.

When the bottom portion is injection molded on the bottom portion of the base portion, it is preferable that shrinkage preventing protrusions are formed on the bottom side of the inner side surface of the housing and the bottom surface of the base portion so that the bottom portion is integrated with the housing without shrinkage.

According to the present invention, the waterproof film is attached to the entire housing base and the contact dome, and prevents the penetration of moisture from the outside into the interior by the bottom portion integrally injection-molded on the bottom of the base, the position of the contact dome Along with the effect of preventing the deviation, the elasticity of the film cover disposed above the stem can prevent the stem unstable shaking due to the assembly tolerance when assembling the stem, and the elastic force acts on the stem and the elasticity of the push lever The cover is firmly fastened to the housing by a hook through a fastening groove of a flange portion formed in the switch cover, so that the film cover remains stable without being lifted up, and no position change at the assembly center occurs so that the tact switch It has the effect of improving product reliability.

1 is a schematic exploded perspective view showing the structure of a conventional tact switch.
Figure 2 is an exploded perspective view showing a tact switch structure according to the present invention.
3 is a cross-sectional view of the tact switch of FIG. 2 assembled;
Figure 4 is a side view of a state in which the tact switch of the present invention is assembled.
5 is a bottom view of the case of the state in which the tact switch of FIG. 2 is first assembled;
6 is a perspective view of a state in which the bottom cover part is integrally injection molded on the bottom of the case base part by injection molding after FIG. 5.
7 to 9 are plan views showing modifications of the film cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown.

2 and 3, the tact switch according to the present invention includes a plurality of lead pieces such that the five internal terminals 101 forming the center contact and four contacts arranged opposite to each other are exposed in the embodiment shown in the drawing. A housing 105 having a base portion 103 on which the 102 is disposed is provided at a bottom thereof, a contact dome 106 made of a conductive metal disposed on the respective inner terminals 101, and selectively contacting the respective contact domes. A stem 107 for pressing and selectively connecting the lead pieces, a hole 108 formed in the center of the stem, and a push lever 109 for a switching operation by a user and a cover 110 for sealing an upper portion of the housing. ).

The stem 107 responds when the push lever 109 is manipulated laterally by forming projections 115 laterally branched to corresponding positions to selectively open and close the contact by pressing the four terminals disposed outside. As the protruding portion 115 in the lower direction is moved downward, the corresponding contact domes are pressed to electrically connect the inner terminal disposed in the center and the inner terminal disposed in the side to perform a predetermined function.

According to the invention, between the protrusions 115 of the stem 107 and the five contact domes 106 is arranged a waterproof film 111 having a contour that is entirely consistent with the contour of the inner wall of the housing 105. The waterproof film is entirely adhered on the upper surface of the base part 103 and the contact dome 106 by a silicone or acrylic adhesive, and the waterproof film is integrated with the contact dome and the base part by heat in an injection molding process described later. In addition, even if the waterproof film is attached to the upper surface of the base portion and the adhesive on the contact dome, the elasticity is adequate to accommodate the deformation during the action of the contact dome is elastically pressed and returned to its original position when the stem is operated by the operation of the push lever. It is preferable to have.

Thus, even if moisture is penetrated into the housing from the outside, the moisture does not penetrate into the contact dome and terminals by the waterproof film 111, so that it has a complete waterproof function.

In addition, the contact dome is not provided with a separate fixing means is disposed in the groove formed in the base portion, even if disposed on the contact dome on the cover of the housing is loosely fixed or loosen as part of the assembly as a whole when the use is in use In some cases, the contact dome is separated from its position, and in this case, a problem in which the accurate switching is not performed by the operation of the push lever may occur in the conventional tact switch, but the contact dome is made by the waterproof film 111 according to the present invention. As 106 remains firmly in place, the problem of switching malfunctions is eliminated.

In addition, as shown in FIGS. 2 and 3, an elastic film cover 120 is disposed above the stem 107 and disposed on an inner side of the cover 110, and an inner hole 121 of the film cover 120 is provided. Peripheral portion 124 is elastically curved on the inclined outer surface of the stem is applied to the elastic force downward on the stem 107 to prevent the phenomenon that the stem unstable shaking by the assembly tolerances when assembling the stem The elastic force acts on the stem to provide a feeling of elasticity to the push lever, and prevents foreign matter and water from penetrating into the housing. The film cover 120 is formed of a heat-resistant synthetic resin to withstand the high heat in the process of soldering the tact switch to the circuit board, the holes 125 are formed in the outer periphery of the film cover, the protrusion 125 formed on the upper end of the housing To be assembled and retained. In addition, the film cover prevents the solder from being attached to the cover from being reversed during soldering of the tact switch, thereby preventing the malfunction of the stem.

As can be seen in the side view shown in Figure 4, when the hook fastening groove 126 is formed in the flange portion 125 formed in the tact switch cover 110 of the present invention is the flange portion 125 when the cover is assembled to the housing ) Is bent and the hook 127 is disposed outside the flange portion through the fastening groove 126 to be firmly assembled in a state where the cover is in close contact with the housing so that the film cover 120 does not lift and stably resilient the stem. While maintaining the assembled state to act, the position change at the assembly center where the push lever is disposed is prevented from occurring.

The bottom portion 130 is integrally formed by the injection molding on the bottom side of the base provided in the housing of the tact switch shown in FIG. 5 so that water from the bottom side of the tact switch bottom is fixed to the terminal fixing portion 131 having a hole shape. It is prevented from entering through to get a perfect waterproof effect. When the bottom portion 130 is injection molded into the housing as shown in FIG. 6, the bottom portion 130 of the bottom surface of the inner side of the lower portion of the housing and the bottom of the base portion is disposed so that a gap does not occur between the housing and the housing. Shrinkage preventing protrusions 140 and 141 are formed to firmly integrate the bottom portion, the base portion, and the housing formed by injection molding.

7, 8, and 9 show a modification of the film cover 120, respectively, and the inner hole 121 of the film cover to enable a smooth elastic deformation on the outer circumferential surface of the stem when the film cover is fitted to the stem Grooves 151, 151 ', 151 "may be formed at four positions facing each other at the shape of the grooves. The grooves may have four rectangular grooves 151 arranged in a cross shape as shown in FIG. As shown in FIG. 8, a rectangular groove 151 ′ disposed in an X shape may be disposed, and the inlet side may be rounded as shown in FIG. 9 as another variation of the modification of FIG. 7. It may be formed in the form of a treated groove 151 ". The film cover 120 according to the modified examples shown in FIGS. 7 to 9 give a smooth operation feeling than the inner hole 121 is formed as a simple circular hole in the film cover shown in FIG. 2.

The present invention is to solve the problem of circuit damage due to the penetration of moisture from the outside to the inside in a tact switch for performing a plurality of functions in a home appliance, for example, by the waterproof film and injection molding It is completely prevented by the bottom part formed in the bottom part, and the solder that can flow back during soldering of the tact switch penetrates between the stem and the cover, so that the problem of the malfunction of the stem is prevented by the elastic film cover. The reliability is improved.

101: terminal 102; Lead piece
103: base portion 105; housing
106; Contact Dome 107 Stem
109; Push lever 110: cover
111: waterproof film 120: film cover
125: flange 126: fastening groove
127: hook 130: bottom
140,141: turning

Claims (6)

A housing 105 having a base portion 103 on which a plurality of lead pieces 102 are disposed, the bottom of which is disposed so that a plurality of inner terminals 101 forming a contact are exposed, and a housing base on the respective inner terminals 101. A conductive metal contact dome 106 disposed on a sheet formed in the portion, a stem 107 for selectively connecting the respective contact domes to electrically connect the lead pieces, and a hole 108 formed in the center of the stem. A tact switch having a push lever 109 inserted therein for a switching operation by a user and a cover 110 for sealing an upper portion of the housing,
Waterproof film 111 having an outer contour that is generally matched to the contour of the inner wall of housing 105 to keep the contact domes 106 in place on the sheet and prevent moisture from penetrating into the contact dome. ) Is adhered to the upper surface of the base portion 103 and the contact dome 106 as a whole, and an elastic film cover 120 having a hole 121 formed therethrough so that the stem 107 penetrates above and above the stem. (110) disposed on the inner side and provided so that the elastic force downward acts on the stem 107, the inner periphery of the hole 121 of the film cover 120 is on the inclined outer side of the stem Tact switch, characterized in that arranged in an elastically curved state. delete The bottom surface portion 130 is integrally formed by injection molding on the bottom surface side of the base portion provided in the housing to prevent moisture from flowing through the terminal fixing portion 131 from the bottom surface of the tact switch. Tact switch to make. According to claim 1, wherein the flange portion 125 is formed in the cover 110, when the flange portion is bent to assemble the cover in the housing, the flange portion 125 so that the cover is firmly assembled in close contact with the housing Tact switch, characterized in that the hook 127 is fastened through the fastening groove 126 formed in the). According to claim 3, When the bottom portion 130 is injection molded on the bottom of the base portion 103, the bottom surface of the inner surface of the lower end and the base portion of the housing so that the gap is not formed between the housing by shrinkage is integrated Tact switch, characterized in that the contraction preventing projections (140,141) of the bottom portion 130 is formed. The tact switch of claim 1, wherein the film cover (120) has grooves (151, 151 ', 151 ") formed at opposite positions for smooth elastic deformation of the periphery (124) of the inner hole (121).

Images