JPH07123014B2 - Lock switch for electric tools - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lock switch for a power tool such as a torque control power tool.

<< Prior Art >> In a torque-controlled power tool, a lock switch is provided separately from the start switch so that the motor stops rotating even when the start switch is in the on state when a torque exceeding a certain limit is applied. There is. FIG. 6 shows a circuit showing the relationship between the start switch and the lock switch. The normally open contact a and the normally closed contact b of the starting switch 1 are connected to the positive electrode and the negative electrode of the power source 2, respectively. The normally open contact b of the lock switch 3 is the start switch 1
Of the lock switch 3 and the normally open contact a of the lock switch 3 is connected to the negative electrode of the power supply 2. Lock switch 3
Is connected to the positive electrode of the motor 4, and the negative electrode of the motor 4 is connected to the negative electrode of the power supply 2.

When the start switch 1 is switched from the contact b side to the a side, the circuit is closed and the motor 4 rotates. When the torque exceeds the specified value, the lock switch 3 switches from the contact b side to the a side, the circuit opens, the rotation of the motor 4 is stopped, and the burnout of the motor 4 is prevented.

The lock switch 3 is interlocked with the torque control mechanism, and when the torque exceeds a specified value, the torque detection member is pulled to turn off the lock switch 3, and the state is held by the alternate mechanism. Then, when the excess torque state is resolved, the alternate switch returns the lock switch 3 to the ON state.

<< Problems to be Solved by the Invention >> As described above, in the conventional torque control type electric tool, two switches, that is, a starting switch for rotating the motor and a lock switch for controlling the torque have been used. Therefore, the number of parts is large, the wiring work and the assembling work are many, and the cost is high, and the structure and the arrangement space are large, and the product itself tends to be large and heavy.

Therefore, it is an object of the present invention to provide a lock switch for an electric power tool that can be reduced in size and weight at low cost.

<< Means for Solving the Problem >> A lock switch for an electric power tool according to the present invention includes a lock member that is arranged to face an actuator of the switch and is movable between a first position and a second position; An operating lever facing each other when positioned at the 1st position, and an operating member of an electric tool for pressing the operating lever, and pressing the lock member via the operating lever by the operation of the operating member, A lock switch for an electric tool for turning on an actuator of the switch, wherein when the lock member moves to a second position while the switch is in an on state, the lock member and the operating lever are opposed to each other. The switch is forcibly released to turn off the switch.

<Operation> In normal operation, the lock member is located at the first position, and when the operating member is pressed in this state, the switch is turned on via the lock member. When the lock member moves from the first position to the second position due to excess torque in this ON state,
Since the switch cannot be operated by the lock member, the switch is turned off.

<< Embodiment >> FIG. 1 is an exploded perspective view of a lock switch showing an embodiment of the present invention, FIG. 2 is an assembly plan view thereof, and FIG. 3 is an assembly front view thereof.

In these figures, a snap-action type micro switch 10 is attached to a holder 11 via a bolt 12. The holder 11 integrally includes a base portion 13, a switch mounting arm portion 14, a sliding guide portion 15, a spring receiving portion 16, an operation lever mounting arm portion 17, and the like.

The switch mounting arm portion 14 has a screw hole through which the bolt 12 is screwed through one mounting hole 18 of the micro switch 10.
19 and a through hole 22 having a boss 21 that is inserted into the other mounting hole 20 of the micro switch 10 and positioned.

The sliding guide portion 15 is composed of two guide pieces 23, 24 on the upper and lower sides of the outer side, and one guide piece 25 cut and raised in the inner center portion in parallel with the guide pieces 23, 24. The guide piece 25 is inserted into the elongated hole 27 of the slide piece 26, and the slide piece 26 is held so as to be sandwiched between the outer guide pieces 23 and 24 and the inner guide piece 25. In order to ensure this holding, projecting pieces may be projected from the upper part of the guide piece 23 and the lower part of the guide piece 24, and may be bent inward to guide or hold the sliding piece 26, The upper and lower portions of the sliding piece 26 may be cut and raised inward to guide or hold the upper and lower sides of the guide piece 25.

The sliding piece 26 has a U-shape in which both ends 28, 29 are bent inwardly at a substantially right angle, and an L-shaped leaf spring 30 as a lock member is provided outside the one end 28 on the microswitch side.
The proximal end portion of is fastened by a pin 31. The pin 31 projects from the inside of the one end 28, and
It also serves as a guide pin of a compression coil spring 32 interposed between the spring receiving portion 16 of the holder 11 and the spring 28. The other end 29 of the sliding piece 26 is formed in a fork shape, and a connecting rod (not shown) is connected thereto so that the sliding piece 26 can be pulled through the connecting rod when the torque exceeds a certain value. I'm running.

Sliding guide 15 of holder 11 and operating lever mounting arm 17
An operating lever guide piece 33 is integrally bent and formed between and. A pin 34 is provided on the flat upper surface of the pin 34 so as to face upward, an operating lever 35 is rotatably attached to the pin 34, and an E-ring 36 prevents the pin from coming off.

The actuating lever 35 is higher on the front end side and the rear end side than the center of rotation thereof, and the front end side is bent inward at a substantially right angle so that the front end 37 overlaps the front end of the leaf spring 30. Facing each other.

The operation lever attachment arm portion 17 has a lower end portion rounded into a tubular shape to form a bearing portion 38, and the lower end portion of the operation lever 39 as an operation member is rotatably attached to the bearing portion 38 by a pin 40. Has been. A compression coil spring 41 is interposed between the mounting arm portion 17 and the operation lever 39 to urge the operation lever 39 away from the mounting arm portion 17. This urging force is
It is regulated by hitting the stopper piece 42 (see FIG. 2 and FIG. 3) that is bent and formed. Also, the operating lever
A guide groove 43 is formed in the upper part of the 39, and the operation lever guide piece 33 of the holder 11 is inserted into the guide groove 43, so that the operation lever
The projection 44 formed on the inner side of the upper portion of the guide lever 39 is guided by the swinging motion of the slide member 39, and abuts on the back of the operating lever 35 to slide.

As shown in FIG. 2, attach the micro switch 10 to the holder 11
, The leaf spring 30 pressed to the micro switch 10 side by the coil spring 32 is
The push button 45, which is the actuator of 10, is covered and faces the tip end 37 of the actuating lever 35. Then, in this state, that is, the sliding piece 26 is biased toward the micro switch 10 side by the coil spring 32,
The state in which the leaf spring 30, which is a locking member, is located at the first position facing the tip end 37 of the actuating lever 35 is the normal state of the lock switch.

When the operation lever 39 is pressed toward the micro switch 10 from this plain state as shown in FIG. 4, (in the case of an electric tool, the operation lever 39 is gripped and tightened between the operation lever 39 and the main body of the electric tool). Pressed), operation lever 39
The protrusion 44 on the upper part of the lever pushes the tip side of the operating lever 35,
A push button 45, which is an actuator of the micro switch 10, is pushed through the leaf spring 30, and the micro switch 10 is turned on to rotate the motor.

In this operating state, the torque becomes excessive and the sliding piece 26
When is pulled to the side opposite to the micro switch 10, the leaf spring 30 is located at the second position where it is disengaged from the tip 37 of the actuating lever 35 and is released from the pressing force of the actuating lever 35, as shown in FIG. At the same time, the push button 45 and the leaf spring 30 are restored to their original state by their restoring force, the micro switch 10 is turned off, and the motor rotation is stopped.

In this locked state, even if the operating lever 39 is pressed, the leaf spring 30 is disengaged from the tip end 37 of the operating lever 35, so that the micro switch 10 cannot be turned on and the motor does not rotate. Even if the excess torque is eliminated, the pressing force of the operating lever 39 is temporarily released to move the leaf spring 30 to the operating lever 35.
The micro switch 10 must be made to face the tip 37 of the
Cannot be turned on. Therefore, the motor is prevented from rotating unexpectedly.

Although the present invention has been described based on the preferred embodiments, the lock switch according to the present invention can be variously modified. For example, a leaf spring 30 that is a locking member
Is not necessarily a leaf spring, and the structure for moving the leaf spring 30 by the sliding piece 26 can be changed to another structure such as a link. Further, an operation push button can be used as the operation member without depending on the operation lever 39.
Furthermore, the locking member may be directly pressed by the operating member without using the actuating lever 35. Further, it is possible to use various actuator structures as the switch itself.

<< Effects of the Invention >> As described above, the lock switch for an electric tool according to the present invention uses a single switch as a start switch and a lock switch in a conventional electric tool, so that the number of parts, wiring work and assembly work are reduced. Therefore, the cost can be reduced. Further, since the structure and arrangement space can be reduced, the product can be made smaller and lighter, and when the lock member is moved to the second position while the switch is in the on state, the lock member and the operating lever face each other. By forcibly releasing the relationship and turning off the switch, when the torque of the electric tool exceeds the specified value,
The rotation of the motor can be stopped to prevent burning and the like.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a lock switch for a power tool showing an embodiment of the present invention, FIG. 2 is an assembly plan view of the switch, FIG. 3 is an assembly front view of the switch, and FIG. ,
FIG. 5 is an assembly plan view for explaining the operation when the lock member of the switch is located at the first position, and FIG. 5 is an assembly plan view for the operation description when the lock member of the switch is located at the second position. , FIG. 6 is an electric circuit diagram using a start switch and a lock switch in a conventional electric power tool. 10 …… Switch, 11 …… Holder, 26 …… Sliding piece, 30…
… Leaf spring (lock member), 32 …… Coil spring, 35 …… Actuating lever, 39 …… Operating lever (operating member), 45 …… Actuator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fusoya Fusoya 3-11-8 Sumiyoshi-cho, Anjo City, Aichi Prefecture Makita Denki Seisakusho Co., Ltd. (72) Meiji Hayashi 3-11 Sumiyoshi-cho, Anjo City, Aichi Prefecture 8 Makita Denki Seisakusho Co., Ltd. (56) Bibliographic references Sho 50-63639 (JP, U)

Claims (1)

[Claims] 1. A first device facing a switch actuator.
A lock member movably provided between the position and the second position, an operation lever facing the lock member when the lock member is in the first position, and an operation member of an electric tool for pressing the operation lever. A lock switch for an electric tool, wherein the lock member is pressed by the operation lever via the operation lever to turn on the actuator of the switch, and the lock is kept in the ON state. A lock switch for an electric tool, characterized in that when the member moves to the second position, the facing relationship between the lock member and the operating lever is forcibly released to turn off the switch.