KR20100057745A - Soldering flux free tact switch - Google Patents

Abstract

PURPOSE: A soldering flux free tact switch is provided to prevent the entry of soldering flux inside a terminal unit of a case by interposing a sealing cap between a metal cover and the case. CONSTITUTION: A case(23) has a terminal unit. An internal terminal is formed on the bottom of the terminal unit. A contact(17) is arranged on the upper side of the internal terminal. A stem(9) pressurizes the contact. A metal cover(1) fixes the contact and the stem to the terminal unit of the case. A sealing cap(41) is arranged between the metal cover and the case. The sealing cap is assembled with the case and the stem in order to hermetically seal the terminal unit of the case.

Description

Soldering Flux Free Tact Switch {SOLDERING FLUX FREE 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 4mm × 4mm × 1mm size tact switch produces a terminal pattern printed circuit board (PCB) in which a plurality of switch terminals of the same pattern are continuously printed on an epoxy substrate or a phenol substrate (mostly an epoxy substrate is used). After coating the remaining parts except the pattern area with an insulating film, a contact is disposed on the upper surface of each terminal pattern, the entire printed circuit board is covered with a dust cover, and then individualized by each terminal pattern and contact unit. Was prepared).

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. The micro tact switch is formed by inserting a micro synthetic resin case body around the inner terminal and the outer terminal to form a recessed terminal chamber on the upper inner terminal, and stacking the contact and stem in the terminal chamber, It is made by assembling the case, contact and stem into one body. To this end, a central opening in which the knob of the stem is inserted is formed in the metal cover, and wings are formed on both sides to surround the entire case body. Since the metal cover is plastic, the case, the contact, and the stem can be assembled into one body by bending the wing under the case body.

In the electrical assembly of such a synthetic resin case-type tact switch to another circuit on the keypad or printed circuit board, an external terminal of the tact switch is formed on the pattern of the keypad board or the printed circuit board by using a SMD mounting device mounter. 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, a soldering flux of salt is applied to the surface of the lead to prevent the surface of the molten lead from being oxidized in contact with the atmosphere. To form a thin flux film. 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 outer terminal of the case lower part, the soldering flux rides on the case body or the metal cover surface due to the vibration of the SMD mounter. It flows into the terminal room of the case. Soldering flux introduced into the terminal chamber enters between the contact and the inner terminal to block electrical contact between the contact and the inner terminal, 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, in the process of mounting the tact switch on the keypad board or printed circuit board, the soldering flux can be prevented from flowing into the terminal room of the synthetic resin case To provide a flux free tact switch.

The present invention to achieve the above object is a synthetic resin case (case) having a terminal chamber with an inner terminal formed on the bottom, a contact made of a metal material (contact) on the upper surface of the inner terminal of the case, so as to enjoy the contact A tact switch comprising a resin stem provided above a contact and a metal cover fixing the contact and the stem to a terminal chamber of the case while inserting a knob of the stem into a central opening. Between the metal cover and the case, characterized in that it is provided with a closure cap for assembling the case and the stem to seal the upper portion of the terminal chamber of the case.

The left and right side walls having an inner surface inclined inwardly toward the lower side of the terminal chamber upper left and right sides of the case are formed such that the left and right outer surfaces of the body of the closure cap are tightly coupled with the inner surface of the left and right side walls of the case downwardly. desirable.

According to the present invention having the above-described configuration, when mounting the tact switch on the substrate, the soldering flux is prevented from flowing into the terminal compartment of the case by the case body or the metal cover, thereby preventing electrical contact between the internal terminal and the contact caused by the flux. There is a preventable effect.

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

1 is an exploded perspective view showing an enlarged soldering flux free tact switch of about 25 times according to the present invention, FIG. 2 is an assembled perspective view of the soldering flux free tact switch shown in FIG. 1, and FIG. 3 is shown in FIG. 2. Front sectional view of a soldering flux pretact switch.

Soldering flux pretact switch according to the present invention, as shown in Figures 1 and 2, the inner terminal while the injection molding the ultra-small plastic case body 25 around the inner terminal 27 and the outer terminal 33 (27) A recessed terminal chamber 31 is formed in the upper portion, and the contact 17, the dust cover 53, and the stem 9 are laminated on the terminal chamber 31, and the sealing cap 41 is used for the above-mentioned. After sealing the terminal chamber 31 of the case, as shown in FIG. 2, the case 23, the contact 17, the dust cover 53, the stem 9 and the sealing cap by the metal cover 1. It is made by assembling 41 into 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 on both sides a lower wing 7 which can cover the entire case body 25 is formed. do. On both ends of the upper surface of the metal cover 1, side openings 5 into which the fastening guides 29 of the case 23 to be described later are inserted are formed. In addition, the upper end of the downward wing (7) protrudes forward, and forms a front wing (41) that can cover the side wall of the body 25 of the case 23 when assembled with the case (23). Since the metal cover 1 has plasticity, when the lower wing 7 is bent into the case body 25, the case 23, the contact 17, the dust cover 53, the stem 9, and the sealing cap are provided. (41) can be assembled in one body.

1 and 2, a feature of the present invention is assembled between the case 23 and the stem 9 between the metal cover 1 and the case 23 to form a terminal chamber of the case 23. It turns out that the sealing cap 41 which seals the 31 is provided.

The body 25 of the case has a substantially rectangular parallelepiped, and the terminal chamber 31 is formed to be recessed in the center of the upper surface. An inner terminal 27 is formed at the bottom of the terminal chamber 31, and the inner terminal is electrically connected to an outer terminal 33 formed outside the body 25 of the case. Through the external terminal 33, the tact switch is connected to a printed circuit board or the like. Thus, the external terminal 33 is soldered with the pattern of the printed circuit board when mounting on the substrate. Sidewalls 39 are formed on the left and right sides of the terminal chamber 31 and inserted into the side openings 5 of the metal cover 1 when the case 23 and the metal cover 1 are assembled at the center of the sidewall 39. The fastening guide 29 is formed.

In the drop test or the like of the tact switch, in order to prevent the metal cover 1 from being detached when an impact is applied, a protrusion 37 is formed on the left and right side walls of the case 23 and the metal cover 1 It is preferable to form a jaw (35) that is caught by the protrusion 37 in the lower wing (7). The forming point of the jaw 35 is a point separated from the front wing 41 of the metal cover 1 by the height of the protrusion 37. Therefore, as shown in FIG. 2, when the front wing 41 is formed at a height that can be joined to the upper surface of the protrusion 37 during assembly, the protrusion 37 is assembled with the front wing 41 and the jaw ( 35) It is clamped in between. Through this, even if an impact is applied to the tact switch, the metal cover 1 is not separated.

The stem (9) is inserted into the central opening (3) of the metal cover 1, the knob 11 is exposed upward, the flange 13 extending outward from the lower end of the knob 11, It is formed to protrude downward from the lower surface of the knob (11) consists of a pressing projection (15) for pressing the central elastic moving portion 19 of the contact (17).

The sealing cap 41 has a rectangular cylindrical body 45 press-fitted between the side walls 39 of the case 1, and extends outward from the upper end of both sides of the body 45 to the case 1. It is configured to include an arm 47 that is placed on the upper surface of the side wall 39 when engaged. The stem hole 43 is formed in the center of the body 45 of the sealing cap 41 so that the stem 13 can be assembled upward from the bottom thereof. The lower portion of the stem hole 43 is the size of the flange 13 of the stem 13, the upper portion is the size that the knob 11 of the stem 13 is inserted, due to the size difference of the upper and lower parts, the stem hole (43) The stop jaw 49 on which the flange of the stem 9 is caught is formed in the upper both side walls.

1 and 3, a dust cover 53 is interposed between the stem 9 and the contact 17, and the dust cover 53 has a larger area than the plane of the terminal chamber 31. It is molded so that the dust cover 53 does not enter the terminal chamber 31, but is pressed and fixed by the upper surface of the case body 25 and the lower surface of the sealing cap body 45 at the upper edge of the terminal chamber 31. desirable. By doing so, it is possible to effectively prevent the inflow of soldering flux.

In addition, as shown in FIG. 3, the inner surface 51 of the left and right side walls 39 of the case 23 is inclined inwardly toward the lower side, and is molded so that the interval between the side walls 39 gradually narrows. When the left and right outer surfaces of the body 45 of the sealing cap 41 are press-fitted so as to be tightly coupled, the sealing cap 41 may not be separated by an external shock, and the terminal chamber 31 of the case 23 may be separated. It is possible to reliably block the flux from entering.

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.

1 is an exploded perspective view showing an enlarged soldering flux pretact switch according to the present invention about 25 times.

FIG. 2 is an assembled perspective view of the soldering flux pretact switch shown in FIG. 1.

FIG. 3 is a front sectional view of the soldering flux pretact switch shown in FIG. 2.

                 Explanation of symbols on the main parts of the drawings

1: metal cover 3: center opening

5: side opening 7: downward wing

9: stem 11: knob

13: flange 15: crimping projection

17 contact 19 elastic moving part

21: short circuit 23: case

25: case body 27: internal terminal

29: fastening guide 31: terminal room

33: external terminal 35: step

37: protrusion 39: side wall

41: sealing cap 43: stem ball

45: sealing cap body 47: arm

49: stop jaw 51: inner side wall

53: dust cover

Claims (4)

Synthetic resin case 23 having a terminal compartment 31 having an inner terminal 27 formed therein, and a metal contact 17 deposited on an upper surface of the inner terminal 27 of the case 23. The contact 17 is inserted into the central opening 3 by inserting the stem of the resin 9 and the knob 11 of the stem 9 provided above the contact 17 so as to receive the contact 17. And a metal cover 1 for fixing the stem 9 to the terminal chamber 31 of the case 23. Between the metal cover 1 and the case 23 is provided with a sealing cap 41 which is assembled with the case 23 and the stem 9 to seal the terminal chamber 31 of the case 23. Soldering flux pretact switch, characterized in that. The method of claim 1, A dust cover 53 is interposed between the stem 9 and the contact 17, and the dust cover 53 is formed to have a larger area than that of the terminal chamber 31 so that the dust cover 53 is formed in the terminal chamber. (31) A soldering flux pretact switch characterized in that the upper end edge of the terminal chamber (31) is pressed and fixed by the upper surface of the case body (25) and the lower surface of the sealing cap body (45). The method of claim 1, The left and right side walls 39 having an inner surface inclined inward toward the lower side are formed on the upper left and right sides of the terminal chamber 31 of the case 23 so that the left and right outer surfaces of the body 45 of the sealing cap 41 are the case. Soldering flux pre-tact switch characterized in that the closer to the inner surface of the left and right side wall of the (23) toward closer. The method of claim 1, Protruding portions 37 are formed on the outer surfaces of the left and right side walls of the case 23, and a lower jaw 7 of the metal cover 1 is formed with a jaw 35 caught by the protruding portions 37 to impact the tact switch. Soldering flux pre-tact switch characterized in that the metal cover (1) is prevented from being separated when it is applied.

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