JPH0773019B2 - Lock switch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lock switch in a torque control type power tool or the like.

<< 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 closed 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 rock switch for an electric power tool or the like which can be reduced in size and weight at low cost.

<< Means for Solving the Problem >> The lock switch according to the present invention is one in which the conventional start switch and lock switch are combined, and the holder holding the switch and the base end portion are fixed to this switch or the holder. At the same time, the free end is made to face the actuator of the switch, and further the leaf spring to which the torque detecting member is coupled to the intermediate portion and the holder rotatably attached to the holder are arranged so that the tip faces the free end of the leaf spring in the normal state. The operating lever is provided with a free end portion of the leaf spring that is disengaged from the tip of the leaf spring when the leaf spring is pulled by the torque detection member, and an operating member that can press the operating lever.

<Operation> When the operating member is pressed, the tip of the operating lever presses the free end of the leaf spring to operate the actuator of the switch to the ON state. When the torque detection member pulls the leaf spring due to excess torque in this ON state, the free end portion of the leaf spring is pulled and disengaged from the tip of the actuating lever, and the free end portion of the leaf spring develops its own elastic force. While returning to the original position,
The switch actuator also returns to its original off state,
The switch is in a locked state in which the switch does not operate even when the operating member is pressed.

<< Embodiment >> FIG. 1 is a plan view of a lock switch showing an embodiment of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a perspective view of a leaf spring used in this lock switch.

The snap-action type micro switch 10 is attached to a resin holder 11 with bolts 12. Further, the leaf spring 13 formed in a substantially U-shape has a tongue piece 13a at the base end thereof sandwiched between the switch 10 and the holder 11 and fixed by being tightened together by the same bolt 12.
The base end of the leaf spring 13 may be fixed to another position of the switch 10 or may be fixed to another position of the holder 11.
A daruma-shaped hole 14 is formed in the middle portion 13b of the leaf spring 13,
Into this hole 14, a tip portion of a shaft 16 which is a torque detecting member guided by the guide hole 15 of the holder 11 is coupled. For this connection, the large diameter portion 16a at the tip of the shaft 16 is
After being inserted into the large diameter portion 14a of the
By engaging with the small diameter portion 14b of the hole 14.
A free end portion 13c of the leaf spring 13 faces a push button 17 which is an actuator of the switch 10, and a tip 13d thereof is folded back to have a rounded shape.

The actuating lever 18 is rotatably attached to the holder 11 by a pin 19 with a leg portion 18b which is bent above and below a flat intermediate portion 18a. A rear end portion 18c of the actuating lever 18 is raised, and a front end portion 18d thereof is bent into a substantially L-shape and is raised so as to raise the neck, and a tip end 18e is formed.
Faces the free end 13c of the leaf spring.

An operation piece 21a of an operation lever 21, which is an operation member protruding from the guide hole 20 of the holder 11, is in contact with the back surface of the intermediate portion 18a of the operation lever 18. The operating lever 21 is the holder 11
It is rotatably attached to the lower end portion of the foot portion 11a by a pin 22, and is normally urged in a direction away from the foot portion 11a by a built-in compression coil spring (not shown).

From the normal state shown in FIGS. 1 and 2, the operation lever 21
When is pressed to the side of the foot 11a of the holder 11 (in the case of an electric tool, the operation lever 21 is pressed by gripping the operation lever 21 with the main body of the electric tool). Move to the right in the figure to move the operating lever 1
Push down the tip 18d of 8. As a result, as shown in FIG. 4, the tip 18e of the actuating lever 18 pushes the free end 13c of the leaf spring 13 to push the push button 17 of the switch 10, and the switch 10 is turned on to rotate the motor. When the pressing force on the operating lever 21 is released, the operating lever 21 self-returns due to its built-in coil spring, and its operating piece 21a moves leftward in the figure to kick the rear end portion 18c of the operating lever 18 to tip it. When 18d is lifted, the leaf spring 13 and the push button 17 are returned by their own restoring force to the off state shown in FIG. 1, and the rotation of the motor is stopped.

When the shaft 16 is pulled to the side opposite to the micro switch 10 due to excessive torque in the operating state shown in FIG. 4, the intermediate portion 13b of the leaf spring 13 is pulled as shown in FIG. The free end tip 13d of the lever is released from the tip 18e of the operating lever 18 and released from the pressing force of the operating lever 18,
The push button 17 and the free end portion 13c of the leaf spring 13 are returned to their original positions by their own restoring force, the micro switch 10 is turned off, and the rotation of the motor is stopped. At this time, the leaf spring 13
The intermediate portion 13b is pulled by the shaft 16 and elastically deformed.

In this locked state, the micro switch 10 cannot be turned on because the free end portion 13c of the leaf spring 13 is disengaged from the tip end 18e of the operating lever 18 no matter how much the operating lever 21 is pressed, the motor 10 cannot be turned on. Does not rotate.

When the excess torque is eliminated, the shaft 16 is pulled toward the micro switch 10 by the self-resetting action of the intermediate portion 13b of the elastically deformed leaf spring 13, and the free end tip 13d of the leaf spring 13 is actuated by the operating lever. It is pressed against the inside of the tip portion 18d of 18. When the pressing force applied to the operating lever 21 is released from this state, the operating lever 21 self-returns due to its built-in coil spring, and the operating piece 21a is moved to the rear end portion 18c of the operating lever 18.
And lift the tip 18d. As a result, the free end 13d of the leaf spring 13 that is pressed against the inside of the operating lever tip 18d slides inside the operating lever tip 18d and slips under the tip 18e, resulting in the normal state shown in FIG. Return. If the pressing force on the operation lever 21 is released first and the actuating lever tip portion 18d is lifted, the free end portion of the leaf spring 13 is restored by the self-restoring force of the leaf spring 13 when the excess torque is eliminated.
13c faces the tip 18e of the operating lever 18 and returns to the normal state shown in FIG.

<< Effects of the Invention >> As described above, the lock switch according to the present invention uses the start switch and the lock switch in the conventional electric power tool and the like as a single switch, so that it is possible to reduce the number of parts, wiring work, and assembly work. Therefore, the cost can be reduced. Further, since the structure and the arrangement space can be reduced, it is possible to reduce the size and weight of the product.
Especially, since the locking operation, the unlocking operation, and the self-returning operation are performed by using one leaf spring,
The structure is extremely simple, the occurrence of failures due to wear, loosening, breakage, etc. is reduced, and a lock switch with a long life can be realized.

[Brief description of drawings]

FIG. 1 is a plan view of a lock switch showing an embodiment of the present invention, FIG. 2 is a front view of the switch, FIG. 3 is a perspective view of a leaf spring in the switch, and FIG. 4 is the switch. FIG. 5 is a plan view showing an operating state in FIG. 5, FIG. 5 is a plan view showing a locking state in the same switch, and FIG. 6 is an electric circuit diagram using a starting switch and a lock switch in a conventional electric tool. 10 ... Switch, 11 ... Holder, 13 ... Leaf spring, 16 ... Shaft (torque detection member), 17 ... Actuator, 18 ... Actuating lever, 21 ... Operating lever (operating member).

 ─────────────────────────────────────────────────── ─── Continuation of 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 8th Makita Electric Co., Ltd.

Claims (1)

[Claims] 1. A holder holding a switch, and a leaf spring having a base end fixed to the switch or the holder, a free end facing the actuator of the switch, and a torque detecting member coupled to an intermediate portion. , Rotatably attached to the holder so that the tip end faces the free end portion of the leaf spring in a normal state, and when the leaf spring is pulled by the torque detection member, the free end of the leaf spring is pulled from the tip end. A lock switch provided with an operating lever whose part is disengaged and an operating member capable of pressing the operating lever.