JP2751358B2 - Trigger switch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a trigger switch used for an electric tool or the like.

<< Prior Art >> A trigger switch is a switch provided with a trigger (trigger) such as a pistol, and the switch is operated by pressing the trigger with a finger.

FIG. 4 shows an example of such a trigger switch. The trigger 1 is rotatably mounted at an intermediate portion thereof to one end of a case 3 via a support shaft 2, and a tip of the trigger 1 is in contact with a push button 4 protruding from an upper portion of the case 3. The trigger 1 is urged to rotate clockwise in the figure by a return spring against the case 3, and the push button 4 is urged upward by a rotation spring by a switch mechanism disposed in the case 3. I have.

By pressing the back 5 of the trigger 1 with a finger, the tip of the trigger 1 presses the push button 4, and the push button 4 activates the switch mechanism in the case 3. When the pressing force on the trigger 1 is released, the trigger 1 and the push button 4 are returned to the original state by the return spring of the trigger 1 and the movable spring of the switch mechanism.

<< Problems to be Solved by the Invention >> Even in such a trigger switch, a more compact trigger switch has recently been demanded. this is,
There is a demand for not only a small shape but also a low-load type in terms of operating load.

However, most conventional trigger switches have a limit in miniaturization because the trigger 1 largely projects outside the case 3 and a slide member such as a push button 4 projects from the case 1 as shown in the figure. Also, since a high load seesaw type is often used as a switch mechanism, the realization of a low load type trigger switch has been neglected. Further, since the slide member such as the push button 4 protrudes from the case 3, there is a problem in the sealing property.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact trigger switch having a low load and good sealing performance.

<< Means for Solving the Problems >> In a trigger switch according to the present invention, an operation shaft rotatable around a support shaft with respect to a case is disposed in the case, and one end of the trigger switch rotates in a direction away from the case. The other end of the biased trigger is disposed on the support shaft so as to rotate integrally with the operation shaft, and the trigger is formed with a pair of leg pieces that straddle the case and overlap the side wall of the case. In addition, a movable contact is provided at a distal end of the movable piece that is displaced by the rotation of the operation shaft, and a fixed contact is provided in the case so as to face the movable contact.

<< Embodiment >> FIG. 1 shows an embodiment of a trigger switch according to the present invention, and FIG. 2 is a front view showing the appearance thereof.

A synthetic resin case 11 has a lever-shaped operation shaft that is opened on the front side and that rotates around a support shaft 12 therein.
A switch 13 is operated by the displacement of the operation shaft 13. From the movable terminal 14 at the lower part of the operation shaft 13, a locking piece 16 whose tip extends to the opening 15 of the operation shaft 13 is integrally provided upright. A base end of a movable piece 17 is swingably attached to a distal end of the locking piece 16 via a metal holder 18.
The movable piece 17 has a hollow hole in the middle part
A movable spring 19 curved upward and convex from the distal end edge of 17a is integrally formed, and the distal end of the movable spring 19 is elastically locked by the locking piece 16 so that the base end of the movable piece 17 is It is locked to. A movable contact 20 is fixed to the tip of the movable piece 17. The support structure of the movable piece 17 is the same as that of a general micro switch. The lower position facing the movable contact 20 is a fixed piece integrally extended from the fixed terminal 21.
A fixed contact 23 fixed to the tip of 22 is located. Reference numerals 24 and 25 indicate terminal fixing screw holes, 26 indicates a switch mounting hole, and 27 indicates a relay terminal.

The support shaft 12 formed on one side surface of the operation shaft 13 includes a round shaft 28 and a square shaft 29 whose both surfaces are cut in parallel. The round shaft 28 is
As shown in FIG. 3, the case 11 is mounted so as to close the front opening thereof, is rotatably supported by a round hole 31 of a cover 30 constituting the entire case, and the square shaft 29 is made of synthetic resin. Square hole 34 formed in one leg piece 33 of the trigger 32
Is inserted so that it cannot rotate. The other leg of the legs formed so as to overlap the side wall of the case 11 that straddles the case 11 and cover 30 assembly of the trigger 32
In 35, a round hole 36 having the same diameter as the one round hole 31 is formed coaxially with a round hole 31, and a round shaft 37 protruding from the back of the case 11 is rotatably inserted into this round hole 36. I have. The small-diameter round shaft 38, which is the support shaft 12 protruded from the other side of the operation shaft 13,
The case 11 is rotatably inserted into a small-diameter round hole 39 recessed inside the round shaft 37. And as shown in FIG.
Boss 40 and case 11 protruding inside the tip of trigger 32
A compression coil spring 42 is interposed between the blind hole 41 formed on the upper surface of the case 11 and biases the trigger 32 about the support shaft 12 in a direction away from the upper surface of the case 11.

Next, the operation of the trigger switch will be described.
In FIG. 1, when the trigger 32 is pressed against the spring 42, the operation shaft 13 rotates in the same direction via the square shaft 29, and the upper end edge 15a of the distal end opening 15 pushes the movable piece 17. When the movable piece 17 exceeds a certain dead center position, the movable piece 17 is inverted by the movable spring 19 and the movable contact 20 comes into contact with the fixed contact 23, which is taken out as an electric signal through the movable terminal 14 and the fixed terminal 21 to the outside. . When the pressing force on the trigger 32 is released, the trigger 32 returns with the restoring force of the spring 42, the operating shaft 13 also rotates in the same direction, and the movable piece 17
And the movable contact 20 is separated from the fixed contact 23.

The coupling for integrating the trigger 32 with the operation shaft 13 in the case 11 is performed by using one of the square shaft 29 as shown in FIG.
34, and the other is fitted as a round shaft 38 into the round hole 39 of the case 11 and indirectly connected to the trigger 32 via the round shaft 37 of the case 11.
Since the other round hole 39 of 11 does not penetrate, the sealing performance is extremely good. Of course, the coupling between the trigger 32 and the operation shaft 13 may be a non-circular fitting such as the square shaft 29 and the square hole 34. Further, a round shaft is protruded from both sides of the operation shaft 13 so as to protrude from the round holes of the case 11 and the cover 30, and the front end portion is fixed to the hole of the trigger 32 by caulking or press-fitting. Is also good. In addition, other connecting and fixing means using screws or the like may be used.

The switch mechanism in the case 11 may be a snap action mechanism as in the embodiment, or a slow type mechanism that directly presses the elastic movable piece.

<< Effect of the Invention >> As described above, the trigger switch according to the present invention
An operation shaft movable about a support shaft with respect to the case is disposed in the case, and the other end of the trigger whose one end is rotationally biased in a direction away from the case is integrally rotated with the operation shaft. A pair of leg pieces is formed on the trigger so as to straddle the case and overlap the side wall of the case, and the tip of a movable piece displaced by the rotation of the operation shaft. A movable contact is provided in the part,
Since the fixed contact is provided on the case so as to face the movable contact, the rotation fulcrum of the trigger is located inside the case, so that the entire switch can be made smaller and the load can be reduced. It becomes possible, and since there is no slide member protruding from the case, the sealing property is improved, and a structure for sealing is not required, so that the cost can be reduced.

[Brief description of the drawings]

1 is a front sectional view of a trigger switch showing one embodiment of the present invention, FIG. 2 is a front view of the switch, FIG. 3 is a schematic side sectional view of the switch, and FIG. It is a front view which shows an example of the trigger switch of FIG. 11 Case, 12 Support shaft, 13 Operation shaft, 14 Movable terminal, 17 Movable piece, 18 Receptacle, 19 Movable spring, 20
…… Movable contact, 21 …… Fixed terminal, 23 …… Fixed contact, 28…
... Round axis, 29 ... Square axis, 30 ... Cover, 32 ... Trigger,
34 ... Square hole, 42 ... Compression coil spring.

Claims (1)

(57) [Claims] An operation shaft rotatable about a support shaft with respect to a case is disposed in the case, and the other end of the trigger whose one end is biased in a direction away from the case is operated. The trigger is formed on the support shaft so as to rotate integrally with a shaft, and the trigger is formed with a pair of leg pieces that straddle the case and overlap the side wall of the case, and is displaced by the rotation of the operation shaft. A trigger switch comprising: a movable contact provided at a tip end of a movable piece to be formed; and a fixed contact provided in the case so as to face the movable contact.