JPH0252369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved pushbutton switch with a self-locking mechanism.

Until now, this type of push button switch has a self-locking mechanism formed by a heart cam groove carved into the key stem side and a locking pin that is attached to the housing and biased by a spring and moves within the heart cam groove. Using a heart cam mechanism, a movable contact attached to a key stem that alternately reciprocates between two stop positions each time a push is made by the heart cam mechanism selectively bridges between fixed contacts to perform the desired switching operation. It was something I was forced to do. In such a conventional push button switch, a self-locking mechanism and a movable contact for switching are provided separately, which requires space for each, which hinders miniaturization.

The present invention has been made in view of this point, and provides a self-locking push button switch that can be miniaturized by integrally configuring a self-locking mechanism and a movable contact. A lock protrusion protrudes from the side surface of the key stem inside the housing, and a slider is installed on the side of the housing from which the lock protrusion protrudes, at right angles to the sliding direction of the key stem. It is stored so that it can be slid in any direction, and
A plurality of fixed contacts with which the slider slides are fixedly arranged at predetermined intervals in the sliding direction of the slider, and the slider has an annular shape forming a reverse cam mechanism that is engaged with the lock protrusion. A heart-shaped cam groove is engraved therein, and a movable contact is provided on at least a surface that slides into contact with the fixed contact, and the cam groove has a movable contact set in the sliding direction of the slider corresponding to an interval between the fixed contacts. a first stable point and a second stable point, which are arranged at a predetermined interval and stably stop sliding of the key stem in the direction of the biasing force of the spring; A self-locking type embossing device characterized in that each time the release is repeated, the plurality of fixed contacts are selectively bridged by the movable contact which alternately reciprocates between two stable stop positions corresponding to the two stable points. It resides in the button switch.

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

FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, and FIG. 3 is a front view of a slider showing an example of a cam groove. In each figure, 1 is a housing, 2 is a key stem, 3 is a coil spring, 4 is a slider, 51 to 53 are fixed contacts, and 6 is an upper lid. The housing 1 is, for example, a molded product made of hard plastic, and has three fixed contacts 51 to 53 having spring properties exposed on one of its inner wall surfaces. Moreover, ribs 11 in the longitudinal direction are provided on a pair of inner wall surfaces sandwiching the inner wall surfaces.

The key stem 2 is also a similar hard plastic molded product, and is provided with a guide groove 21 on the side surface, and by fitting the guide groove 21 with the rib 11, it can freely slide in the housing 1 in the axial direction. be accommodated in. The shoulder 22 of the key stem 2 is prevented from coming off by the upper cover 6 attached to the housing 1.
This is done by touching the The coil spring 3 is interposed between the bottom surface of the housing 1 and the ceiling of the cavity 23 of the key stem 2, and constantly applies upward pressure to the key stem 2.

The slider 4 is made of a conductive material, and the surface that contacts the fixed contacts 51 to 53 itself functions as a movable contact. The key stem 2 is slidably housed therebetween along the back surface of the key stem 2 in a direction perpendicular to the sliding direction of the key stem 2. The vertical movement of the slider 4 is suppressed by the bottom surface of the housing 1 and the upper cover 6, and the fixed contact 5
It is pressed against the back surface of the key stem 2 by spring pressures 1 to 53. At this time, a lock protrusion 24 protruding from the back surface of the key stem 2 is engaged with a heart-shaped cam groove 40 carved in the slider 4.

The heart-shaped cam groove 40 includes a first stable point 41 and a second stable point 42, which are arranged at a distance shown by D in FIG. 3 in the sliding direction of the slider 4. This is an annular groove connecting a first stop point 43 and a second stop point 44 arranged in the middle of the path between the two ends. Here, the first and second stable points 41, 4
2 is a place where the lock protrusion 22, which is pressed upward by the coil spring 3, stops, and the first and second stopping points 43, 44 are pressed downward by the key stem 2. This is where the lock protrusion 22 stops. Also, the interval D
defines the amount of movement of the slider 4, and is set to enable switching operation in accordance with the arrangement spacing of the fixed contacts 51-53.

This heart-shaped cam groove 40 forms a reverse cam mechanism, and locks the lock protrusion 2 as the key stem 2 slides.
Slanted sides 45 to 48 are provided for converting vertical movement of slider 4 into horizontal movement of slider 4. The bottom surface of the heart-shaped cam groove 40 has an upward slope in the direction of relative movement of the lock protrusion 24, and step portions 49 are provided at key points to prevent the lock protrusion 24 from moving backwards. . As a result, when the key stem 2 is pressed against the biasing force of the spring 3, the lock protrusion 24 is moved to the inclined side 45.
It is guided from the first stable point 41 to the first stop point 43 and stopped there in a pressed state, and when the pressure is released, the urging force of the spring 3 moves it along the inclined side 46 to the first stop. It is guided from the point 43 to the second stable point 42 and stably stopped there, and when the key stem 2 is pressed again, it is guided from the second stable point 42 to the second stopping point 44 by the inclined side 47 and is pressed here. When this pressure is released, the second
It is guided from the stopping point 44 to the first stable point 41, where it is stably stopped, and the slider 4 is slid in each predetermined direction for each of the above operations.

Thus, the self-locking pushbutton switch
The key stem 2, a spring 3 that biases the key stem 2, and a slider 4 having a heart-shaped cam groove 40 that engages with the lock protrusion 24 of the key stem 2 constitute a self-locking mechanism. The movable contact of the slider 4 alternately reciprocates between the two stable stop positions corresponding to both the stable points 41 and 42 each time the pressing force is applied and released repeatedly, and between the plurality of fixed contacts 51, 52, 53. It is selectively bridging.

Next, the operation of the self-locking push button switch constructed in this manner will be explained.

First, it is assumed that the lock protrusion 24 is stopped at the first stable point 41 of the heart-shaped cam groove 40 as an initial state. In this case, the slider 4 is located on the left side and bridges the fixed contacts 51 and 52. Here, when the key stem 2 is pressed down, the lock protrusion 24 descends and presses the inclined side 45 of the heart-shaped cam groove 40. Therefore, the slider 4 moves in the direction shown by arrow A in FIG. It falls and stops descending.

When the pressure on the key stem 2 is removed in this state, the key stem 2 is raised by the spring pressure of the coil spring 3. Therefore, although the lock protrusion 24 also rises, it cannot return to its original path due to the action of the step portion 49 connected to the sloped side 46, and presses this step portion 49 and the sloped side 46, causing the slider 4 to rise. Return to the direction opposite to arrow A. This movement of the slider 4 is stopped when the lock projection 24 reaches a second stable point 42. Therefore, with one pressing operation of the key stem 2, the lock protrusion 24 moves from the first stable point 41 to the second stable point 42, and the slider 4 moves by a distance D in the direction of the arrow A. This opens the connection between the fixed contacts 51 and 52, and connects the fixed contacts 52 and 53, thereby switching the switch.

Next, in this switching state, the key stem 2
When pressed again, the lock protrusion 24 moves to the stepped portion 49.
This action prevents the slider 4 from moving backward, and the slider 4 is moved slightly in the direction opposite to the arrow A by pressing the stepped portion 49 and the inclined side 47. The downward movement of the locking protrusion 24 stops when the locking protrusion 24 reaches the second stop point 44, and the key stem 2 can no longer be depressed.

When the pressure on the key stem 2 is removed in this state, the spring pressure of the coil spring 3 causes the lock protrusion 2 to
4 presses the stepped portion 49 and the inclined side 48 and moves the slider 4 in the direction opposite to the arrow A while moving upward. In this case as well, the action of the stepped portion 49 prevents the lock protrusion 24 from moving backward. This rise of the lock protrusion 24 causes the lock protrusion 24 to reach the first stable point 41.
reaches and stops. As a result, the slider 4 moves by a distance D in the direction opposite to the arrow A and returns to its initial state, and the fixed contact 52 is separated from 53 and 51
can be switched to.

Thereafter, this operation is repeated every time the key stem 2 is pressed.

Although detailed explanation has been given above according to the illustrated embodiment,
It goes without saying that the present invention is not limited to this. For example, the same effect can be achieved even if the slider is made of a hard plastic molded product and a conductive material such as a metal plate is fixed as a movable contact to the sliding surface of the fixed contact. Furthermore, the fixed contact may be arranged in various locations, such as between the slider and the top cover, but in this case, a spring may be required to press the slider against the lock protrusion. Further, the shape of the heart-shaped cam groove is merely an example, and various variations are possible. For example, as shown in FIG. 4, the end of the inclined side 45 or 47 is located directly below the first and second stable points 41, 42, and the end of the inclined side 45 or 47 is located directly below the first and second stable points 43, 44 Slanted side 46 or 48 on top
If it is formed so that the end of the lock protrusion 24 is located
moves as shown by the arrow in the same figure, and no retrograde movement occurs.
Therefore, there is no need to provide a stepped portion, a slope, etc. on the bottom surface of the heart-shaped cam groove 40.

As described above, according to the present invention, the slider that performs the self-locking function also functions as a movable contact, so there is no need to consider the space for arranging the movable contact, and a self-locking push button switch that can be easily miniaturized can be obtained. .

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the present invention, FIG. 2 is a vertical sectional view thereof, and FIGS. 3 and 4 are front views of a slider showing an example of a heart-shaped cam groove. It is. DESCRIPTION OF SYMBOLS 1... Housing, 11... Rib, 2... Key stem, 21... Guide groove, 22... Shoulder, 23
... Cavity part, 24 ... Lock projection, 3 ... Coil spring, 4 ... Slider, 40 ... Heart-shaped cam groove, 41 ... First stable point, 42 ... Second stable point, 43 ...First stop point, 44...Second stop point, 45
~48...Slope side, 49...Step part, 51-53
...Fixed contact, 6...Top lid.

Claims (1)

[Claims] 1. A key stem is housed in a housing so as to be slidably biased by a spring, a lock protrusion protrudes from the side surface of the key stem inside the housing, and a slider is attached to the side of the housing from which the lock protrusion protrudes. The slider is housed so as to be slidable in a direction perpendicular to the sliding direction, and a plurality of fixed contacts with which this slider comes into sliding contact are fixedly arranged at predetermined intervals in the sliding direction of the slider, and the sliding The slider is provided with an annular heart-shaped cam groove constituting a reverse cam mechanism that engages with the lock protrusion, and has a movable contact on at least a surface that slides into contact with the fixed contact; A first stable point and a second stable point are arranged at a predetermined interval that corresponds to the interval between the fixed contacts in the sliding direction of the key stem and stably stop the sliding of the key stem in the direction of the biasing force of the spring. The plurality of fixed contacts are the movable contacts, which have two stable points, and alternately reciprocate between two stable stop positions corresponding to the two stable points each time a pressing force is applied to the key stem and released. A self-locking push button switch that selectively bridges between