KR100971654B1 - Flux proof tact switch - Google Patents

Abstract

The present invention relates to a synthetic resin case type tact switch used in a communication and information processing device such as an MP3 player, an MP4 player (video player), a mobile communication terminal, a PDA, and the like. (case), a metal contact placed on an upper surface of the inner terminal of the case, a synthetic resin stem provided above the contact to receive the contact, and the knob of the stem is inserted into the central opening. A tact switch composed of a metal cover for fixing the contact and the stem to a terminal chamber of the case, wherein a soldering flux is formed around the center opening of the metal cover. In order to prevent the penetration into the terminal compartment of the case, an injection molded synthetic hermetic seal is provided integrally with the metal cover. According to the present invention, according to the present invention, by preventing the flux from flowing into the terminal chamber of the case through the metal cover during soldering, it is possible to prevent the electrical contact failure between the internal terminal and the contact by the flux There is.

Tact Switch, Flux

Description

Flux ingress tact switch {FLUX PROOF TACT SWITCH}

The present invention relates to a tact switch, and more particularly, to a synthetic resin case type tact switch used in a communication and information processing device such as an MP3 player, an MP4 player (video player), a mobile communication terminal, a PDA, and the like.

The tact switch deposits a conductor elastic contact or an elastic movable metal (also called a metal dome) on a substrate on which a pattern of terminals is formed, and inputs or releases an electrical signal between terminals connected to the contact by pressing and releasing the contact. It is used to open and close the door. Such a tact switch is provided on a keypad board or a printed circuit board (PCB) such as an MP3 player, an MP4 player (video player), a mobile communication terminal, a PDA, and a communication and information processing device such as a PDA. Intermittent electrical signals or power. In recent years, as the portable communication and information processing devices such as mobile communication terminals and PDAs become smaller and lighter, the size of the tact switch used here is also required to be reduced. Conventionally, a tact switch having a size of about 4 mm × 4 mm × 1 mm produces a terminal pattern printed circuit board (PCB) that continuously prints the same pattern of switch terminals on an epoxy substrate or a phenol substrate (mostly an epoxy substrate is used). After coating the remaining portion except the portion with an insulator, a contact was placed on the terminal pattern and covered with a dust cover, and the printed circuit board to which the contact was bonded was cut into each contact unit.

However, in recent years, there is a growing demand for ultra-small tact switches having a size of 1 mm x 2 mm x 1 mm.

1A is an exploded perspective view showing an enlarged micro tact switch of 25 times or more, and FIG. 1B is an assembled perspective view of the tact switch shown in FIG. 1A. As shown in FIG. 1A, the micro tact switch is a terminal recessed in the upper portion of the inner terminal 27 while injection molding the micro resin case body 25 around the inner terminal 27 and the outer terminal 33. After the seal 31 is formed and the contacts 17 and the stem 9 are laminated on the terminal chamber 31, as shown in FIG. 1B, the case 23 and the contact are made by the metal cover 1. (17) and stem (9) is made by assembling one body. To this end, the metal cover 1 is formed with a central opening 3 into which the knob 11 of the stem 9 is inserted, and wings 7 which surround the entire case body 25 are formed at both sides. . Since the metal cover 1 has plasticity, the case 23, the contact 17, and the stem 9 may be assembled into one body by bending the blade 7 under the case body 25.

In the electrical assembly of such a synthetic resin case-type tact switch to another circuit on the keypad or printed circuit board, the external terminal of the tact switch is mounted on the pattern of the keypad or printed circuit board by using a SMD mounting surface mount device. Solder to the solder. However, when soldering, the conventional synthetic resin case-type tact switch has the following problems and needs to be improved.

When soldering a synthetic case type tact switch to a keypad board or a printed circuit board, lead is dissolved. At this time, in order to prevent the surface of the molten lead from contacting the atmosphere, it is necessary to make a thin layer of salt on the surface of the lead by using salt ( flux). However, since the conventional synthetic resin case type tact switch is extremely small in size, even if a small amount of flux is applied around the lower external terminal, the flux may ride on the metal cover surface to allow the flux to ride on the metal cover surface. 31). The flux introduced into the terminal chamber 31 blocks the electrical contact between the contact 17 and the internal terminal 27, causing a problem that the tact switch does not operate.

The present invention, which is intended to solve the problems of the conventional synthetic resin case-type tact switch described above is to prevent the flux inflow that can block the flux flowing into the terminal room of the synthetic resin case when soldering the tact switch to the keypad or printed circuit board To provide a tact switch.

The present invention to achieve the above object is a synthetic resin case (case) having a terminal chamber formed with a terminal pattern on the bottom, a contact made of metal material (contact) deposited on the upper surface of the terminal of the case, the contact so as to enjoy the contact A tact switch composed of a synthetic resin stem provided above and a metal cover for fixing the contact and the stem to a terminal chamber of the case while inserting a knob of the stem into a central opening. Around the central opening of the cover, a plastic injection seal is integrally inserted into the metal cover to prevent the flux for soldering from penetrating the surface of the metal cover into the terminal compartment of the case. It is characterized by.

The case and the hermetic seal are preferably molded by injection using LCP (Liquid Crystal Polymer) or polyamide, but the material is not necessarily limited thereto.

According to the present invention having the above-described configuration, it is possible to prevent the flux from flowing into the terminal chamber of the case through the metal cover at the time of soldering, thereby preventing the electrical contact failure between the internal terminal and the contact by the flux.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

First, reference is made to FIG. 4. 4 is an exploded perspective view of a flux inflow preventing tact switch according to the present invention. As shown in FIG. 4, the flux inflow preventing tact switch according to the present invention has a synthetic resin case 131 having a terminal compartment 135 having an inner terminal 137 formed therein, and the case 131. A metal contact disposed on the upper surface of the inner terminal 135 of the contact, and a synthetic resin stem (115) provided above the contact to receive the contact. In order to assemble the contact 125 and the stem 115 to the terminal chamber 135 of the case 131, the metal cover 101 is used, but the metal cover 101 is used as it is. Rather, airtight teeth 109a, 109b, and 109c are formed in the central opening 105, and the flux flowing through the metal cover surface during soldering is inherently infiltrated into the terminal chamber 135 of the case 131. It is a characteristic of the present invention to block.

The features of the present invention will become more apparent from the following description.

FIG. 2A is a plan view of the metal cover 101 used for the flux inflow preventing tact switch according to the present invention, and FIG. 2B is a front view of the metal cover 101 shown in FIG. 1A.

Referring to FIGS. 2A and 2B, the metal cover 101 is manufactured by punching a thin metal sheet by a press, and an upper plate 3 of a central portion disposed on an upper surface of the case 131 during assembly, and a case 131 during assembly. It includes both wings 107 that can surround both sides and the bottom. A central opening 105 is formed in the upper plate 3, and gas seals 109a, 109b, and 109c are formed around the central opening 105. During assembly, the metal cover 101 is bent at the first bend line BL1 and the second bend line BL2. In order to improve the plasticity at the time of bending, it is preferable to use nickel silver as the material of the metal cover 101.

FIG. 3A is a perspective view of the hermetic cover insert-molded hermetic seal in the metal cover shown in FIG. 2A, FIG. 3B is a plan view of the hermetic cover shown in FIG. 3A, and FIG. 3C is A-A 'of FIG. 3D shows a front view of the hermetic cover shown in FIG. 3A, and FIG. 3E shows a bottom view of the hermetic cover shown in FIG. 3A, respectively.

As shown in FIGS. 3A to 3E, a feature of the present invention is that around the center opening 105 of the metal cover 101, a soldering flux rides on the surface of the metal cover 101. In order to prevent penetration into the terminal chamber 135 of the case 131, the synthetic resin material hermetic seals 109a, 109b, and 109c integrally inserted into the metal cover 101 are provided.

In forming the hermetic seals 109a, 109b, and 109c, first, the metal cover 101 is punched into a press, and the molten synthetic resin is injected in the state where the metal cover 101 is inserted into the hermetic mold forming mold. Thereby, the airtight teeth 109a, 109b, and 109c and the metal cover 101 are shape | molded integrally. 3C and 5, the hermetic seal includes an upper hermetic strip 109a forming a wall around the knob 117 of the stem 115 in the metal cover upper plate 103 and the metal cover upper plate 103. The lower airtight seals 109b and 109c are partially inserted into the terminal chamber 135 of the case 131. The upper hermetic rib 109a and the lower hermetic rib 109b and 109c are connected inside the central opening 105, and the stem hole 111 can be disposed inside the hermetic rib 109a, 109b and 109c. ) Is formed. The lower hermetic seals 109b and 109c include a support part 109b supporting the metal cover upper plate 103 and an insertion part 109c closely inserted into the terminal chamber 135 of the case 131.

By this configuration, the metal cover 101 becomes a gastight cover 113 for blocking flux.

As shown in FIG. 4, the contact 125 and the stem 115 are sequentially stacked in the terminal chamber 135 of the case 131, and the stem 115 is placed in the stem hole 111 of the airtight cover 113. When the bent lines BL1 and BL2 of the blade 107 are inserted in the inserted state to surround the outer surface of the case body 133, the flux inflow preventing tact switch as shown in FIG. 5 is completed. In this case, a dust cover 123 made of a thin synthetic resin film may be held on the upper surface of the contact 125 to more reliably block foreign matter from penetrating between the contact 125 and the internal terminal 137.

5 is an assembled perspective view of the flux intrusion preventing tact switch according to the present invention, and FIG. 6 is an enlarged front sectional view of the flux inflow preventing tact switch illustrated in FIG. 5. As shown in FIGS. 5 and 6, the flux flowing through the inner surface of the metal cover 101 or the outer surface of the metal cover 101 is completely blocked so that the flux into the terminal chamber 135 is completely blocked. Is prevented from flowing in between the terminal chamber 135 and the internal terminal 137 and the contact 125 at the source. Therefore, according to the present invention, a poor electrical contact between the internal terminal and the contact due to the flux can be prevented, and a trouble-free tact switch can be obtained.

As mentioned above, although the preferred embodiment of the tact switch which concerns on this invention was described with reference to drawings, it does not intend to limit the protection scope of this invention to this, It is the right to all the embodiments equal to or equivalent to the matter of a claim. Should be interpreted as affecting.

1A is an exploded perspective view of a conventional tact switch.

FIG. 1B is an assembled perspective view of the tact switch shown in FIG. 1A.

Figure 2a is a plan view of a metal cover used in the flux intrusion prevention tact switch according to the present invention.

FIG. 2B is a front view of the metal cover shown in FIG. 1A.

FIG. 3A is a perspective view of an airtight cover in which injection seals are injected into the metal cover shown in FIG. 2A. FIG.

FIG. 3B is a plan view of the hermetic cover shown in FIG. 3A.

3C is a cross-sectional view taken along the line AA ′ of FIG. 3B.

3D is a front view of the hermetic cover shown in FIG. 3A.

3E is a bottom view of the hermetic cover shown in FIG. 3A.

4 is an exploded perspective view of a flux inflow preventing tact switch according to the present invention.

5 is an assembled perspective view of a flux inflow preventing tact switch according to the present invention.

FIG. 6 is an enlarged front cross-sectional view of the flux inflow preventing tact switch shown in FIG. 5.

                 Explanation of symbols on the main parts of the drawings

1: metal cover 3: center opening

5: side opening 7: wing

9: stem 11: knob

13: engaging jaw 15: crimping projection

17 contact 19 elastic moving part

21: short circuit 23: case

25: case body 27: internal terminal

29: fastening protrusion 31: terminal chamber

33: external terminal 101: metal cover

102: top plate 105: center opening

107 wing 109a, 109b, 109c

111: stem ball 113: airtight cover

115: stem 117: knob

119: engaging jaw 121: crimping projection

123: dust cover 125: contact

127: elastic movable portion 129: short circuit

131: case 133: case body

135: terminal chamber 137: internal terminal

139: external terminal

Claims (2)

A synthetic resin case having a terminal chamber having an inner terminal formed on a bottom thereof; A metal contact disposed on an upper surface of the inner terminal of the case; A synthetic resin stem provided above the contact to enjoy the contact; And a metal cover configured to fix the contact and the stem to the terminal chamber of the case while inserting the knob of the stem into a central opening. Around the central opening of the metal cover, an injection-molded synthetic resin material integrally inserted into the metal cover to prevent soldering flux from penetrating the surface of the metal cover into the terminal compartment of the case Wherein the hermetic fillet comprises an upper hermetic fillet forming a wall along the knob periphery of the stem at the top of the metal cover, and a lower hermetic fillet which is partially inserted in the terminal compartment of the case under the metal cover. Flux inflow tact switch characterized by the above-mentioned. delete

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