JP2001195946A - Small-sized push button switch for mounting on long stroke type substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized push button switch for mounting on a long stroke type substrate, in which the switch has the same mounting height from the surface of the substrate as that of the prior art article when mounted on the substrate, but can produce a large stroke and an optional click feeling. SOLUTION: The push button switch comprises a frame shaped in such a manner that a portion of a switch body is fallen and inserted in a switch- mounting hole of a mounting printed-circuit board. Also, it comprises a ring shaped moving contact fixed to a back face of a plunger; two fixed contacts which are disposed on a bottom of the frame and made in contact with the moving contact by pushing down of the plunger; and a restoring device serving to restore the pushing down of the plunger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long-stroke type push button switch for mounting on a board.

[0002]

2. Description of the Related Art A small push button switch called a tact switch having a metal dome or a contact mechanism similar thereto is thin and small and is used for various devices. FIG. 3 shows a schematic sectional view of a typical conventional tact switch. In FIG. 3, 14 is a movable contact called a metal dome, 15 is a fixed contact at the center, 16 is a ring-shaped fixed contact at the periphery, 17 is an external lead terminal connected to the fixed contact 15 at the center, and 18 is a periphery. An external lead terminal connected to the ring-shaped fixed contact 16 of the section, 19 is a frame of the switch body, and 20 is a push button of the switch.

In the operation sequence of this switch, the central roof portion of the metal dome 14 is depressed when the push button 20 is pressed, and the central portion of the rear surface of the metal dome 14 contacts the fixed contact 15. Since the metal dome 14 is in contact with the ring-shaped fixed contact 16 at the outer periphery, the metal dome 14 made of a material such as phosphor bronze allows the fixed contact 15 at the center and the ring-shaped fixed contact 16 at the periphery to be formed. Is electrically connected, and the external lead terminals 17 and 18 are electrically connected. Then, when the push button 20 is released from being pressed, the connection is released because the metal dome 14 returns to its original shape due to its elastic restoring force.

[0004]

With the recent demand for thinner devices, the shape of tact switches has tended to become smaller and thinner, and click feeling and stroke have become extremely small. If the size is reduced from the structure of the metal dome, the stroke will be reduced in proportion to the stroke.
5 mm, and about 0.25 mm for a small one.
However, from the viewpoint of usability, the click feeling and the stroke are extremely important elements of the switch, and contradict the demand for thinning. The present invention has been made in order to solve the above-mentioned problem, and a long-stroke type substrate which can obtain a large stroke and an arbitrary click feeling even when the mounting height from the substrate surface when mounted on the substrate is the same as a conventional product. An object of the present invention is to provide a small push button switch for mounting.

[0005]

According to a first aspect of the present invention, there is provided a small-sized pushbutton switch for mounting on a long-stroke type board, wherein a switch mounting hole is provided in a printed board to be mounted, and a part of the switch body is provided. A frame having a shape to be dropped into the hole, a ring-shaped movable contact fixed to the back surface of the plunger, two fixed contacts installed at the bottom of the frame that comes into contact with the ring-shaped movable contact when the plunger is pressed, and the two fixed contacts Two external lead terminals respectively connected to the contacts and drawn out to a frame portion mounted on a printed circuit board surface pad outside the frame, and a return mechanism installed so as to return pressing of the plunger. Features.

According to the small-sized push button switch for mounting a board on a long stroke type according to the first aspect, the switch body thickness can be secured by the thickness of the printed board even though the mounting height from the printed board surface is the same. A sufficient stroke can be obtained even if the size is reduced, and an appropriate click feeling can be obtained by selecting the strength of the return mechanism.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic cross-sectional view of the structure of a small-sized pushbutton switch for mounting a long-stroke type board, showing an embodiment of the present invention. In FIG. 1, 1 is a movable contact,
2 and 3 are fixed contacts, 4 and 5 are external lead terminals,
6 is a frame of the switch body, 7 is a plunger (push button), 8 is a return mechanism, 9 is a printed board, 10 is a mounting hole provided on the printed board 9, 11 is a pad of the printed board 9, and 12 is an external lead terminal. The solder for connecting the pads 4 and 5 to the pads 11 of the printed circuit board 9 is shown. Although the return mechanism 8 is shown by a coil spring in FIG. 1, a leaf spring or a rubber contact may be used instead. FIG. 2 shows an embodiment in which the rubber contact 13 is used.

The operation of this switch is such that when the plunger 7 is depressed, the movable contact 1 which is a disk or ring-shaped good conductor fixed to the plunger 7 is simultaneously depressed and the fixed contact 2 is pressed.
And 3. The fixed contacts 2 and 3 are short-circuited by the movable contact 1, and the external lead terminals 4 and 5 are electrically connected. When the plunger 7 is released, the movable contact 1 is separated from the fixed contacts 2 and 3 by the restoring force of the return mechanism 8, and the connection state is released.

Next, attachment of the present switch to the printed circuit board 9 will be described. While the conventional tact switch is mounted on a pad 22 of a printed circuit board 21 as shown in FIG. 3, this switch is provided with a mounting hole 10 on a printed circuit board 9 as shown in FIG. The frame 6 of the switch body is dropped and mounted. The frame 6 of the switch body is provided with a brim-shaped protrusion on the printed circuit board so as to hang over the hole edge of the mounting hole 10, and the external lead terminals 4 and 5 extend along the bottom surface of the protrusion. The tips of the external lead terminals 4 and 5 are arranged on the pads 11 of the printed circuit board 9, and are connected to the printed circuit board 9 by the solder 12.

[0010]

According to the present invention, as described above, a part of the frame 6 of the switch body is formed in the mounting hole 1 of the printed circuit board 9.
0, so that even if the mounting height from the surface of the printed circuit board 9 is the same as that of the conventional switch, the thickness of the switch body frame 6 is equal to the thickness of the printed circuit board 9 (about 0.8 mm to 1.2 mm). Switch. Therefore, it is possible to make the stroke of pressing the switch larger than that of the conventional switch by the thickness of the printed circuit board 9. Also, with respect to the click feeling, a good feeling can be realized by increasing the stroke and appropriately selecting the strength of the return mechanism 8. Further, since a part of the frame 6 of the switch body is accommodated in the mounting hole 10 of the printed circuit board 9, the height of the plunger can be increased. It is also possible to do.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross-sectional structure of a long-stroke type small push button switch for mounting a board according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an embodiment of a long-stroke type small push button switch for mounting a board using a rubber contact.

FIG. 3 is a schematic diagram showing a cross-sectional structure of a conventional general tact switch.

[Explanation of symbols]

Reference Signs List 1 movable contact 2 fixed contact 3 fixed contact 4 external lead terminal 5 external lead terminal 6 frame of switch body 7 plunger (push button) 8 return mechanism 9 printed circuit board 10 mounting hole provided on printed circuit board 11 printed circuit board pad 12 solder 13 Rubber Contact 14 Movable Contact (Metal Dome) 15 Central Fixed Contact 16 Peripheral Ring Fixed Contact 17 External Lead Terminal Connected to Central Fixed Contact 18 External Connected to Peripheral Ring Fixed Contact Lead terminal 19 Switch body frame 20 Switch push button 21 Printed circuit board 22 Printed circuit board pad 23 Solder

Claims (1)

[Claims] 1. A small switch having a push button structure,
A frame in which a switch mounting hole is provided in a printed circuit board to be mounted and a part of the switch body is dropped into the hole, a ring-shaped movable contact fixed to the back surface of the plunger, and a frame that comes into contact with the ring-shaped movable contact when the plunger is pressed down. Two fixed contacts installed on the inner bottom portion, two external lead terminals connected to the two fixed contacts and respectively drawn out to a frame portion mounted on a printed circuit board surface pad outside the frame, and a plunger. A small push button switch for mounting on a long-stroke board, comprising: a return mechanism installed to return a press.