JP3489371B2 - Power tool safety devices - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a power tool, and more particularly to a safety device for a power tool for preventing erroneous operation of a trigger. 2. Description of the Related Art
As a safety device for preventing erroneous operation in a power tool such as a nailing machine using compressed air or electricity as a power source, a trigger lever, a swing lever pivotally attached to the trigger lever, and a swing lever from a nose portion of the power tool are provided. And a slidable contact arm reaching the vicinity of the contact arm. [0003] The swing lever is located between the trigger valve and the contact arm, and when the contact arm is pressed against a wall or the like and pushed into the tool body, the end of the swing lever is pushed by the contact arm to trigger. Rotate in the direction of the valve. When the trigger lever is rotated in this state, the swing lever moves in the direction of the trigger valve as a whole, the stem of the trigger valve is pushed in, and the power tool is started.
That is, when only one of the trigger lever and the contact arm is operated, the stem of the trigger valve is not pushed, so that the power tool is not accidentally activated. For example, an extremely thin nail for interior finishing is used. In the case of a nailing machine that requires the nose to be as narrow as possible in order to drive the nail close to the corner between the wall and the floor, such as a nailing machine that drives Some are difficult to provide. As a safety device applicable to such a power tool, a lock lever for restricting rotation of a trigger lever is pivotally attached to a grip portion, and the lock lever is retracted from a rotation path of the trigger lever. There is known a lock lever type safety device in which a trigger valve is operated by two operations of a rotation operation of a lever. However, the above safety device can rotate the lock lever even in the trigger locked state in which only the trigger lever is gripped, and if the lock lever is rotated by mistake while gripping the trigger lever, the restriction is released. In addition, there is a possibility that the trigger lever may rotate to start the power tool, and there is a problem that the reliability of the trigger lock is not sufficient. [0005] Then, there arises a technical problem to be solved in order to improve the reliability of the lock lever type safety device, and an object of the present invention is to solve the above problem. SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object, and a hand-held power tool has a lock position for preventing rotation of a trigger lever of the power tool. And a lock lever that is rotatable to an unlock position, a spring is interposed in the lock lever to urge the lock lever to the lock position, and the lock lever is rotated to retract to the unlock position, whereby the lock lever is retracted to the unlock position. triggering in the safety device of the power tool trigger lever is pivotally operated to the actuated position, the lock lever is located between the bets Rigareba and grip, the further, the lock lever on the first locking position By rotating the lever, engaging means such as an uneven portion or a hook for engaging the trigger lever and the lock lever is provided, and the trigger lever and the lock lever are provided. The lock lever is formed so as to be locked in a non-rotatable state when engaged with the power tool. An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an air nailing machine 1 in which an air cylinder 3 is arranged at a central part in a housing 2, and a head valve 5 is provided between a head cap 4 fitted in an upper end opening of the housing 2 and the air cylinder 3. Has been inserted. The driver bit 7 attached to the piston 6 of the air cylinder 3 reciprocates in the nose 8 connected to the lower end of the housing 2, and nails supplied into the nose 8 from the nail guide 9 connected to the back of the nose 8. Inject. A trigger valve 11 is mounted on the front surface (lower in the figure) of the base of the grip 10 connected to the housing 2, and a valve stem 11a protrudes forward.
The rear of the trigger lever 12 pivotally connected to the valve stem 11
a. A lock lever 13 is pivotally mounted at a position slightly below the trigger valve 11 of the grip 10, and the trigger lever 12 is operated with the index finger of the hand holding the grip 10 to rotate the lock lever 13 with the middle finger. It is arranged. The upper end (left side in FIG. 1) of the lock lever 13 is located between the trigger lever 12 and the grip 10, and has a hook portion 13a projecting from the upper end toward the trigger lever 12. Also, the trigger lever 12
A lock pin 14 facing the upper front of the lock lever 13 is provided laterally on the back surface of the lock lever 13. In FIG. 1, a trigger lever 12 and a lock lever 13 which are rotatable up and down are provided with springs 15 and 16 respectively.
The hook portion 13a of the lock lever 13 is located closer to the shaft 17 of the trigger lever 12 than the lock pin 14 in the standby position, and the lock lever 13 is moved to the grip 10 side. When the lock lever 14 is pulled, the hook portion 13a retreats to the outside of the rotation locus of the lock pin 14, and the lock of the trigger lever 12 is released. A port of the trigger valve 11 operated by the trigger lever 12 is connected to a pilot chamber 19 between the head cap 4 and the head valve 5 through a pilot line 18. When the pressure air in the pilot chamber 19 is exhausted by pushing the valve stem 11 a of the trigger valve 11, the head valve 5 rises and high-pressure air flows from the air chamber 20 in the housing 2 and the grip 10 into the air cylinder 3, and the piston 6 and The driver bit 7 descends and ejects the nail in the nose 8. When the turning operation of the trigger lever 12 is released and the valve stem 11a of the trigger valve 11 returns to the initial position, the head valve 5 is lowered by the pilot pressure to shut off the air chamber 20 and the air cylinder 3. ,
The pressurized air acting on the upper surface of the piston 6 is exhausted to the atmosphere, and the piston 6 and the driver bit 7 return to the standby position by the pressurized air in the blowback chamber 21 provided on the lower outer periphery of the air cylinder 3. Next, the trigger locking operation of the lock lever 13 will be described. In the standby state shown in FIG.
2, the lock pin 14 of the trigger lever 12 comes into contact with the front surface of the lock lever 13, and the rotation of the trigger lever 12 is restricted as in the conventional lock lever type safety device, as shown in FIG. The stem 11a of the valve 11 cannot be pushed. When the lock lever 13 is pulled from the trigger locked state, the hook 13a of the lock lever 13 hits the lock pin 14 and the lock lever 13
Is prevented, so that the trigger lock cannot be released. Therefore, even when the lock lever 13 is mistakenly pulled or the lock lever 13 hits a surrounding object when the gripper 10 of the nailing machine 1 is gripped by the gripper 10 and the trigger lever 12 is pulled, the trigger lever 1
2 does not rotate to the starting position. When performing a nailing operation, pulling the lock lever 13 from the standby state shown in FIG. 1 causes the lock lever 13 to rotate, and as shown in FIG. The lock pin 14 is retracted outside the rotation path. If the trigger lever 12 is pulled in this state, the rotation of the trigger lever 12 is not restricted, and as shown in FIG. 4, the valve stem 11a of the trigger valve 11 is pushed and the nailing machine 1 starts. As described above, when the operation of the lock lever and the trigger lever is performed in the reverse order in releasing the trigger lock, the trigger lock cannot be released, so that an erroneous operation can be prevented. The present invention is not limited to the above-described embodiment, and various modifications are possible within the technical scope of the present invention, and it is natural that the present invention extends to those modifications. is there. [0018] As described above, according to the present invention, the safety device of the present invention, located between the trigger lever and the grip is pivotally secured to the lock lever to the housing, the further, the first locking position By operating the trigger lever with respect to a certain lock lever, an engaging means such as an uneven portion or a hook for engaging the trigger lever and the lock lever is provided, and when the trigger lever and the lock lever are engaged. Since the lock lever is formed so as to be locked in a non-rotatable state, when the trigger lever and the lock lever of the nailing machine are in a standby state, when the trigger lever is pulled,
The trigger lever is engaged with the lock lever by the engaging means, and the rotation of the trigger lever is restricted as in the case of the conventional lock lever type safety device. Then, even if the lock lever is pulled from this trigger locked state, the rotation of the lock lever is prevented by the engaging means, so that the trigger lock cannot be released. Therefore, when the user grips the grip of the nailing machine with his / her hand and moves, for example, with the index finger of the hand pulling the trigger lever, the user accidentally pulls the lock lever with the middle finger, or when the lock lever is moved by surrounding objects. Does not rotate the trigger lever to the start position. Also, when performing the nailing operation, when the trigger lever and the lock lever are at the standby position, if the lock lever is pulled, the lock lever rotates and the engaging means is released. Therefore, if the trigger lever is pulled in this state, the rotation of the trigger lever is not restricted, and the nailing machine starts. As described above, in the safety device of the present invention, the operation sequence of the lock lever and the trigger lever when releasing the trigger lock is defined, and it is impossible to operate the lock lever from the state where the trigger lever is grasped to release the lock. Therefore, the present invention improves the reliability of trigger lock and contributes to prevention of accidents.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention and is a cross-sectional view of an air nailer. FIG. 2 is a partial sectional view showing a trigger locked state. FIG. 3 is a partial sectional view showing a trigger lock released state. FIG. 4 is a cross-sectional view showing a state where a trigger lock is released and a trigger lever is operated. [Description of Signs] 1 Air nailing machine 10 Grip 11 Trigger valve 12 Trigger lever 13 Lock lever 13a Hook portion 14 Lock pin 15 Spring 16 Spring

Claims (1)

(57) [Claim 1] A power tool for hand-held work is provided with a lock lever that is rotatable between a lock position for preventing rotation of a trigger lever of the power tool and an unlock position, A power tool that allows the trigger lever to rotate to an activation position by urging the lock lever to a lock position by interposing a spring and rotating the lock lever to retract to an unlock position is provided. in the safety device, the lock lever between the bets Rigareba and the grip
Position and, further, the first trigger lever by rotating operation on the lock lever in the locked position, provided the engaging means of the concave-convex portion or a hook or the like and the trigger lever and the lock lever is engaged, A safety device for a power tool, wherein the lock lever is locked so as not to rotate when the trigger lever and the lock lever are engaged.