JP2001093382A - Small lever-type detection switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small detection switch operable with small force, small and stable in contact. SOLUTION: A contact spring 5 is depressed and turned by a cam portion 4b, close to the center of turning movement, of a lever to be turned by the contact with a detected object and a contact 5s at the end is slidably displaced on the inner bottom of the case 1 and put in contact with or in separation from a terminal 2 as a fixed armature opposed thereto, whereby a switch is open/closed. The detection switch is obtained, which is small, operable with small force, stable and usable for surface mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a miniature switch, and more particularly, to a miniature switch having a lever for detecting an object with the lever.

[0002]

2. Description of the Related Art An element used for detecting the operation of a mechanism of various kinds of audio equipment and OA equipment or for detecting the opening and closing of a lid of a portable MD, a notebook personal computer, or the like. There is a detection switch that detects when pressed.

[0003]

Such a conventional detection switch has a structure in which an internal contact is turned on or off when a protruding portion protruding from a switch housing is pressed, and the protruding portion is provided. Is a linear movement, which is operated by directly pressing a contact piece made of an elastic material constituting a switch. Therefore, the pressing force required to turn on or off the contact is the force itself to actuate the elastic material contact piece, which may not be able to actuate depending on the object to be detected. Is desired. An object of the present invention is to provide a detection switch that operates with a small operating force, is small, and has a stable contact state of a contact.

[0004]

In order to solve the above-mentioned problems, according to the present invention, a contact spring is pressed by a cam portion provided near a rotation center of a lever which is rotated by the contact pressure of a detection target. The movable contact provided on the contact spring slides and displaces the inner surface of the case, and contacts or separates from a fixed contact piece disposed at a position facing the inner surface to open and close the circuit. .

[0005] In addition, the above problem is solved by the above-mentioned item, in which the contact spring is formed by bending a conductive elastic plate material into a V-shape, one end of which is held by a case as a pivot point, and the other end is provided with a movable contact. The cam portion of the lever can be solved by pressing the vicinity of the V-shaped bent portion.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a detection switch according to the present invention, an object to be detected abuts against the tip of a rotating lever and presses it, whereby a cam provided on the lever moves a movable contact piece to make a contact. Is turned on or off.

The cam portion provided on the lever is provided at a position near the center of rotation of the lever. In this way, the detection operation can be performed even if the pressing force on the lever is small.

A contact spring as a movable contact piece moved by the cam portion is bent in a V-shape, one end of the V-shape is rotatably held by a case and its cover, and a contact is provided on the other end. To In this way, the whole can be made small.

The contact provided on the contact spring slides on the surface of the terminal which is a fixed contact piece provided on the inner surface of the case. The cam portion presses the vicinity of the V-shaped bending point of the contact spring. Therefore, the rotation of the lever is transmitted to the contact spring to rotate it, and the rotation of the contact spring causes the contact at the tip to slide on the terminal surface, and an appropriate pressure is obtained between the two contacts, The ON / OFF operation of the contact is assured.

[0010]

FIG. 1 is a front view of an embodiment of a detection switch according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a top view thereof.
In each figure, 1 is a case, 2 is a terminal, 3 is a cover, 4 is a lever, and 5 is a contact spring.

The case 1 is formed of an insulating resin such as PPS. The details are shown in the top view of FIG.
As shown in the cross-sectional view of FIG. 1, a terminal 2 made of a conductive material such as brass strip is embedded in the bottom surface in advance by insert molding. Terminal 2 comprises a plurality, in FIG. 5, the terminal 2A as shown in arrangement corresponding to the top view of FIG. 3, 2B, consists of three points 2C, the sliding surface 2A ₁ terminal 2A is formed long is, the sliding surface 2B ₁ terminal 2B is shorter, and terminal 2C is formed to a length to penetrate between opposing sides of the case 1 without a sliding surface. The three terminals 2 embedded in the bottom surface of the case 1 partially expose the upper surface of the case 1, that is, the inner surface of the bottom surface, respectively. They are on the same plane.

The use of the terminals 2A, 2B and 2C as switches is shown in the circuit diagram of FIG. The terminal 2A is connected to or separated from the terminal 2A by a contact spring as a movable contact piece described later in combination with the terminal 2B, and the switch is turned on and off. Therefore, at least the surfaces of the exposed sliding surfaces 2A ₁ and 2B ₁ as shown by hatching in FIG. 5 are subjected to a treatment such as silver plating. On the other hand, the terminal 2C is a dummy and has no direct relation to the function of the switch.
This is because when the switch is surface-mounted on the board, four terminals are more stably mounted than two, and the switch is provided to increase the solder strength. Since the two terminals are conductive, Depending on the circuit used, it can be used as a jumper wire.

The portion of each terminal protruding from the case 1 to the outside is bent in two steps as understood from FIG. 2 or FIG. 4 (B), and is suitable for mounting on a substrate surface and mounting by soldering. It has a shape. The projection 1e on the lower surface of the bottom surface of the case 1 is for positioning when mounting the substrate.

Grooves 1a for fitting a pivot shaft of a later-described lever are provided at upper end edges of two opposite surfaces of the side surface of the case 1, respectively. Two grooves 1b for holding a spring are formed, and a groove 1c for receiving a movable portion of a lever, which will also be described later, is formed on the upper edge of the surface facing the intermediate side surface.

FIG. 6 is an exploded perspective view of the detection switch according to the present embodiment. The structure of the cover 3, the lever 4, and the contact spring 5 will be described with reference to FIG. In order to avoid complication, the drawing is partially omitted. The cover 3 is formed of a resin material such as nylon, and has such a shape and dimensions that it is assembled to the upper opening of the case 1 and closed. 3a is cover 3
Hooks projecting from two non-adjacent edges in a direction perpendicular to the lower side. The hooks engage with hooks (not shown) provided at positions corresponding to the hooks 3a on the side surface of the case 1 so that the hooks are mutually connected. Hold. The surface of the hook 3a have been formed square hole 3a _1, fitting the shaft of the lever to be described later. Reference numeral 3b denotes two projections protruding downward from the other edge, which fit into two grooves 1b formed on the upper edge of the case 1, respectively. This is for holding the spring 5.

The lever 4 is formed of a resin such as nylon, like the cover 3, and has a columnar rotating shaft 4a and a width dimension smaller than the length of the rotating shaft 4a extending from the rotating shaft 4a in the radial direction. And a lever-shaped lever portion 4c extending further from the cam portion 4b and having a smaller width than the width of the cam portion 4b. The lever 4c
Extend approximately 45 degrees with respect to the cam portion 4b. Moreover, it has an arc-shaped arc part 4b ₂ Metropolitan cam portion 4b is followed by a flat surface portion 4b _1.

The contact spring 5 is formed of a phosphor bronze strip and functions as a movable contact piece of the switch. The contact spring 5 is bent in a V-shape near the center in the longitudinal direction, and one end is
Each tip is further divided into two parts, and each tip is provided with four spoon-shaped contacts 5s, and at least the portions are silvered or the like. The opposite end portion is bifurcated into two parts, each of which is bent at a substantially right angle to form a holding portion 5b for holding the case 1.

As can be easily understood from FIG. 6, these components are assembled as follows. The plurality of terminals 2 are already embedded in the case 1 by insert molding as described above. The contact spring 5 is inserted from the upper opening of the case 1 in the illustrated direction, and the two forked holding portions 5 b at one end are fitted into the two grooves 1 b of the case 1. The both ends of the rotating shaft 4a of the lever 4 are square holes 3a ₁ of the hook 3a of the cover 3.
After fitting into the groove 1 a of the case 1, the opening is closed by the cover 3 while the projection 3 b of the cover 3 is fitted into the groove 1 b of the case 1. The hook 3a engages with a hook (not shown) of the case 1 to maintain the assembled state.

The state of the detection switch thus assembled is described with reference to the sectional view of FIG. In this sectional view, the terminal 2B is used to explain the open / closed state of the switch.
The side is a cross section. The contact 5s of the contact spring 5 is always in contact with the terminal 2A.

The holding portion 5b at the end of the contact spring 5 is
The contact spring 5 is rotatable about this portion as a fulcrum. The contact spring 5 is displaced by the fact that the holding portion 5b is bent in a shape close to a right angle and that the portion is formed in a forked shape and is fitted in the two grooves 1b of the case 1. There is no. The cam portion 4b of the lever 4 is in the state is being in contact with the flat portion 4b ₁ in the flat upper surface of the contact spring 5, presses the contact spring 5 very lightly.

FIG. 7 shows a state in which the detection switch is assembled as described above, and explains the operation of the detection switch of the present invention thus configured. FIG.
(A) shows the free state of the contact spring 5, in which the bending angle θ is about 40 degrees.

When such a contact spring 5 is assembled as described above, as shown in FIG.
And the bending angle θ becomes about 35 degrees. The contact 5s at one end of the contact spring 5 is in pressure contact with the inner bottom surface of the case 1. In this state, the switch circuit is open since it is separated from the terminal 2B on the inner bottom surface.

When the object to be detected touches the lever portion 4c of the lever 4 and is pressed, the lever 4 rotates in the direction of arrow A, and FIG.
(C), and the contact spring 5 is
bend angle θ by being pressed by the circular arc portion 4b ₂ of b is about 30 degrees. Since the contact 5s at one end of the contact spring 5 contacts the terminal 2B on the inner bottom surface of the case 1, the contact spring 5 short-circuits the terminal 2A and the switch circuit is closed.

When the detection object is further pressed against the lever portion 4c of the lever 4, the lever 4 further rotates in the direction of the arrow A, as shown in FIG. bend angle θ by being pressed by the circular arc portion 4b ₂ is about 24 degrees. The contact 5s maintains the contact state with the terminal 2B and the switch circuit is kept closed.
The state (D) is the full stroke state of the detection switch of the present embodiment. That is, the further rotation of the lever portion 4c of the lever 4 is restricted by the lower end of the groove 1c of the case 1, and the holding portion 5b of the contact spring 5 makes its surface contact with the outer surface of the cover 3 to further rotate. Rotation is restricted.

When the pressing force of the object to be detected against the lever 4 disappears, the contact spring 5 presses the cam portion 4b of the lever 4 by the urging force and rotates the cam portion 4b in the direction opposite to the direction A. To the state of.

Although the above embodiment has been described with reference to a surface mounting type, the present invention can be practiced with respect to other types of usage. Although the switch is always off type, it goes without saying that the switch can be always on type by changing the structure of the terminal.

[0027]

As described above, according to the present invention, the contact spring is pressed and rotated by the cam portion provided near the center of rotation of the lever which rotates upon contact with the object to be detected, and the contact at the tip of the contact spring is rotated. Since the switch is opened and closed by being displaced and coming into and out of contact with the fixed contact piece disposed opposite thereto, the length of the operating portion of the lever can be shortened by using the cam. Further, the operating range of the lever can be shortened, so that the entire switch can be reduced in size, which is effective in saving space.

Also, the operating force is reduced, and the range of use is expanded.

Further, since the movement of the movable piece can be made longer than the short movement of the lever, the ON / OFF operation of the switch is assured.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment of a detection switch according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a top view of the same.

4A is a top view of a case of an embodiment of the detection switch according to the present invention, and FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A.

FIG. 5 is a top view of a terminal.

FIG. 6 is an exploded perspective view of an embodiment of the detection switch according to the present invention.

FIGS. 7A, 7B, 7C, and 7D are explanatory diagrams illustrating the operation of an embodiment of the detection switch of the present invention.

FIG. 8 is a circuit example of an embodiment of the detection switch of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Terminal 3 Cover 4 Lever 4b Cam part 5 Contact spring 5s Contact

Claims (2)

[Claims] 1. A lever which is rotated by the contact pressure of a detection target, a contact spring is pressed by a cam portion provided near a center of rotation, and is rotated, and a movable contact provided on the contact spring moves an inner surface of the case. A small lever type detection switch characterized in that a circuit is opened and closed by sliding displacement and coming into contact with or separating from a fixed contact piece arranged at a position facing the inner surface. 2. A contact spring is formed by bending a conductive elastic plate material into a V-shape, one end of which is held by a case as a pivot point, and a movable contact at the other end. 2. The small lever type detection switch according to claim 1, wherein the switch presses the vicinity of a V-shaped bent portion.