JP2697044B2 - switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application >> The present invention relates to a plurality of fixed contacts having contact surfaces arranged flush with the surface of a resin substrate, The present invention relates to a switch having a movable contact for switching connection between fixed contacts.

<< Prior Art >> This type of switch is found in, for example, a trigger switch for an electric tool.

In the power tool trigger switch, the slider is moved in conjunction with the trigger, and at this time, the movable contact slides on the substrate together with the slider, and the contact switching with the fixed contact provided on the substrate is performed.

FIGS. 6 and 7 show the main parts of a conventional switch using such a contact switching mechanism.

In the figure, a movable contact contact portion 53 is formed on each of the left and right sides of a resin substrate 51 with a slit 52 interposed therebetween, and a plurality of fixed contacts 58 are provided on the movable contact contact portion 53 in a dotted manner. On the other hand, a slider 55 arranged on the substrate 51 and moved along the movable contact contact portion 53 is formed of a synthetic resin material in a block shape, and corresponds to the movable contact contact portion 53. Is provided. Each movable contact 56 is urged downward by a coil spring 57.

In this switch, with the movable contact 56 abutting on the movable contact contact portion 53, the slider 55 is moved along the movable contact contact portion 53 to the position shown by the solid line and the position shown by the dashed line in FIG. And the contact is switched.

<< Problems to be Solved by the Invention >> However, in the above-described conventional structure, the portion 53a on the substrate 51 which moves while the movable contact 56 is in contact with the contact surface 54a of the fixed contact 54 is a simple smooth surface. It is formed as. For this reason, when abrasion powder or an arc product of the movable contact 56 occurs during sliding, the abrasion powder or the arc product accumulates on the movable contact contact portion 53 and is carbonized, causing dielectric breakdown and causing a switching position. Has become unstable and reliability has been reduced.

The present invention has been made in view of the above problems,
An object of the present invention is to provide a switch having a structure capable of improving reliability without dielectric breakdown.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention provides a plurality of fixed contacts whose contact surfaces are flush with the surface of a resin substrate, and which is slid on the substrate. A movable contact for switching the connection between the fixed contacts, wherein a groove is provided on the substrate between the fixed contacts present on a locus on which the movable contact slides, and a groove is provided between the fixed contacts. A plurality of wall portions that are cut off in the middle without being connected linearly to each other are formed in a state where the fixed contacts partially overlap and are juxtaposed.

<< Example >> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 to 3 show one embodiment of a trigger type switch to which a switch according to the present invention is applied. This trigger type switch 1 is roughly composed of a switch body 2
And a trigger member 20 and the like.

The switch main body 2 includes a case main body 3 having therein a storage chamber 4 whose upper and lower surfaces are opened, and a cover 5 attached to cover the upper opening of the case main body 3.
And is defined by A trigger holding portion 6 to which the trigger member 20 is attached is provided integrally with a lower portion of the case body 3. The trigger holding portion 6 is formed in a U-shaped cross section with an open front surface, and the opening and the lower surface opening of the case body 3 are in communication with each other.
Further, a mode switching lever is provided on the upper front surface of the case body 3.
A shaft 12a of the mode switching lever 12 is rotatably extended into the switch body 2, and is operatively connected to a mode switching switch 13. A slider 7 and a movable contact 8 and a coil spring 9 mounted on the slider 7 are arranged in a storage chamber 4 of the case body 3. A contact board 16 shown in FIG. 5 is provided. On the other hand, a slider 7 is provided above the storage chamber 4 with a brush 17 interposed therebetween.
The circuit board 10 is provided so as to cover the upper part of the circuit board. The electronic component mounting unit 11 is mounted on the upper surface of the circuit board 10.
And a fixed contact 14 (see FIGS. 4 and 5) is provided on the lower surface.

On the other hand, the trigger member 20 has, at one end, an operating portion 21 which is disposed in the storage chamber 4 through the trigger holding portion 6 and is freely connected to the engaging recess 7a of the slider 7. Also,
By engaging the engaging projections 23 of the trigger holding part 6 with the engaging holes 22 provided on both right and left sides, the trigger holding part 6
Is rotatably supported. The trigger member 20
Is turned by the biasing force of the coil spring 24 interposed between the trigger member 20 and the trigger holding portion 6 in the counterclockwise direction as shown in FIG. ing.

In the trigger type switch 1, when the lower side of the trigger member 20 is pulled toward the trigger holding portion 6 against the urging force of the coil spring 24, the trigger member 20 is engaged with the engagement protrusion 23 and the engagement hole 22. 1 in a clockwise direction in FIG. At this time, the engagement concave portion 7a and the operating portion
The slider 7 is moved forward through the engagement with 21.
When the pulling force of the trigger member 20 is removed, the trigger member 20 pivots and returns to the position shown in FIG. 1 by the urging force of the coil spring 24, and the slider 7 moves at the same time.
That is, the contact of the slide switch is switched by the movement of the slider 7 in conjunction with the rotation of the trigger member 20.

As shown in FIG. 4 and FIG. 5, only the main part of the slide switch portion is a movable contact contact portion in which the movable contact 8 slides on the left and right sides with the slit 25 interposed therebetween.
26 are provided. When the resin case body 3 is formed, a plurality of fixed contacts 14 are scattered on each movable contact contact portion 26 in a state where the contact surface 14a is exposed flush with the surface of the contact board 16. Inserted. Also,
In each movable contact contact portion 26, a wall 26a, 28b, 28c, 28d extending in the direction of each fixed contact 14 is formed in a portion 26a existing between each movable contact 14 and the fixed contact 14. The walls 28a, 28b, 28c, 28d are formed in such a manner that they are not linearly connected to the adjacent fixed contacts 14, and are cut off in the middle. Further, the position where the wall portions 28a and 28b are provided, the position where the wall portion 28c is provided, and the wall portions 28d and 2
The position where 8e is provided and the position where wall portion 28c is provided are in a state where they partially overlap each other by a dimension t as shown in FIG.

On the other hand, the slider 7 provided with the movable contact 8 corresponding to each movable contact contact portion 26 is formed of a synthetic resin material, and the supporting wall 7 supporting the movable contact 8 at the front and rear ends of both left and right walls.
a and 7a are provided, and a concave portion 29 for receiving the coil spring 9 is provided at the center. On the other hand, each movable contact 8 is formed to be bent in a substantially U-shape and arranged between the support walls 7a of the slider 7. Further, both ends 8a, 8a are bent outward to be able to engage with the upper surfaces of the support walls 7a, 7a. Further, contact portions 8b, 8b swelling downward are provided at front and rear ends of the lower surface. In this configuration, the movable contact 8 is held by the biasing force of the coil spring 9 on the lower side, that is, in a state of being pressed against the movable contact contact portion 26, and slides on the movable contact contact portion 26 by operating the trigger member 20. Thus, contact switching with each fixed contact 14 is performed. At the time of this sliding, the movable contact 8 and the contact board 1
6. When the fixed contact 14 and the like are worn to generate wear powder, the wear powder falls into the groove 27. In addition, products generated by an arc or the like at the time of contact with or separation from each fixed contact 14 also fall into the groove 27 in the same manner. Moreover, since the wall portions 28a, 28b, 28c, 28d, 28e are not continuous with the fixed contacts 14, 14, they are cut off halfway. Part 28
The front and rear edge portions of a, 28b, 28c, 28d, and 28e abut against the sliding contact surface of the movable contact 8, and at this edge portion, abrasion powder and arc products are actively scraped and dropped into the groove 27.

Therefore, in the slide switch portion, even if abrasion powder and arc products are generated, they do not remain on the surface of the movable contact contact portion 26, so that carbonization does not occur and dielectric breakdown does not occur. . This allows
Energization / interruption can be reliably obtained at a position where the movable contact is in contact with or separated from the fixed contact, and reliability can be improved.

Although the structure applied to the trigger type switch is disclosed in the above embodiment, the configuration of the slide switch unit is not limited to the trigger type switch but can be widely applied to a switch using a slide contact mechanism. Also, the wall
Needless to say, the pattern shape of 28 can be variously modified without being limited to this embodiment.

<< Effects of the Invention >> As described above, according to the switch of the present invention, when abrasion powder or an arc product is generated, these can be sequentially dropped from the substrate surface into the groove. In addition, abrasion powder and arc products adhering to the movable contact can be forcibly scraped off at the edges before and after the wall and dropped into the groove. Therefore, it is possible to eliminate the problem that abrasion powder and arc products accumulate on the surface of the substrate and carbonize, thereby causing dielectric breakdown of the substrate portion between the fixed contacts. As a result, energization / interruption can be reliably obtained at a position where the movable contact is in contact with or separated from the fixed contact, and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an example of a trigger type switch to which the present invention is applied, FIG. 2 is a transverse sectional view taken along line II-II of FIG. 1, and FIG. 3 is III-III of FIG. FIG. 4 is a cross-sectional top view taken along a line, FIG. 4 is a perspective view of a main part of the switch, and FIG.
FIG. 6 is a side view of the main part of the switch shown in FIG. 6, FIG. 6 is a perspective view of the main part of a conventional switch, and FIG. 7 is a side view of the main part of the switch shown in FIG. 1 Trigger switch, 7 Slider, 8 Movable contact, 14 Fixed contact, 14a Contact surface, 16
Contact board, 27 ... groove, 28a, 28b, 28c, 28d, 29e ... wall.

Claims (1)

(57) [Claims] A fixed contact having a contact surface flush with a surface of a resin substrate; and a movable contact which is slid on the substrate to switch a connection between the fixed contacts. A switch, wherein a groove is provided on the substrate between the fixed contacts present on a trajectory on which the movable contact slides, and a plurality of cuts are cut off halfway without being connected linearly between the fixed contacts. A switch wherein a wall portion is formed in a state where the wall portion is juxtaposed and partially overlapped between the fixed contacts.