JPH09141563A - Bit slip-off preventing mechanism in drive screwdriver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bit from slipping off a head groove of a screw after driving. SOLUTION: This drive screwdriver is so constituted as to be provided with drive screw impact mechanism for striking a drive screw in a nose part 5 by supplying compressed air into an impact cylinder to drive an impact piston, and screw rotating mechanism for screwing the drive screw, struck by the driving of the impact piston, by an air motor. In this case, lock mechanism (c) is provided to lock a contact arm 21, provided slidably along the nose part 5 and pressed into the body side by pressing the tip to a driven member, out of sliding motion halfway in a moving range, and the lock mechanism (c) is released before the rotation of the air motor on the basis of the on state of a signal for actuating the impact mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a striking mechanism in which a driving screw is driven by a bit of a striking mechanism, and before further screwing, a contact arm is unlocked so that the bit does not come out of a screw head groove. The present invention relates to a bit disengagement prevention mechanism for a turning machine.

[0002]

2. Description of the Related Art Generally, a driving machine for driving a driving screw is a kind of nail driving machine, and is provided with a striking mechanism for striking a driving screw with a bit and a screw rotating mechanism for rotating and screwing the bit after striking. Then, the applicant has proposed a method in which the contact arm is unlocked by interlocking with the rotation of the gear of the screw rotation mechanism after the driving screw is driven and before the screw is driven (Patent application 7 -50
No. 401).

[0003]

However, in the system in which the unlocking of the contact arm is interlocked with the gear of the screw rotating mechanism, the contact arm is unlocked after the bit starts to rotate, so only the driving screw is inserted between them. Screw forward. Therefore, a space is created between the bit and the driving screw, and the engagement between the bit and the head groove of the driving screw is disengaged, so that a phenomenon of cam out easily occurs.

The present invention solves the above problems and, by rotating the bit after the contact arm is unlocked, prevents the bit from coming out of the head groove of the screw after being driven. It is an object to provide a detachment prevention mechanism.

[0005]

In order to solve the above-mentioned problems, a bit disengagement prevention mechanism in a driving machine for driving a screw according to the present invention includes a screw driving bit provided in a striking cylinder provided in a body. The striking piston is slidably housed up and down, and compressed air is supplied into the striking cylinder to drive the striking piston to drive the striking piston in the nose portion provided at the tip of the body. In a driving machine equipped with a striking mechanism and a screw rotating mechanism for screwing a driving screw striking by driving the striking piston by an air motor, the striking mechanism is slidable along the nose portion and its tip is made into a material to be driven. A lock that locks the contact arm that is pushed into the body side by pressing so that it cannot slide in the middle of the movement range. Provided with a structure, characterized in that to release the locking mechanism before the air motor is rotated based on the signal to activate the striking mechanism is turned on.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a driving machine for driving a driving screw, in which a hammering piston 4 equipped with a hammering bit 3 is moved up and down in a hammering cylinder 2 inside a body 1. Slidably housed in the striking cylinder 2
Compressed air is supplied to drive the striking piston 4, and the bit 3 strikes the driving screw 6 in the nose portion 5 provided at the tip of the body 1 until the head is lifted. It is provided with a striking mechanism a and a screw rotating mechanism b for screwing a driving screw 6 hit by the striking piston 4 by an air motor 7 driven by a part of the compressed air supplied to the striking cylinder 2.

Compressed air is supplied from the compressed air supply source into the striking cylinder 2 through the grip 8 and the air chamber 9 formed in the body 1. In addition, drive screw 6
Are connected via a connecting member and housed in the magazine 10 in a coil shape. Then, the screws are supplied one by one into the nose portion 5 by the screw feeding air cylinder device 11.

The striking mechanism a is operated by pulling the trigger lever 12. The trigger valve 13 is actuated by the trigger lever 12, and the head valve 14 is opened and actuated in conjunction with the trigger valve 13 as shown in FIG. 2 to instantly supply the high-pressure compressed air in the air chamber 9 to the striking cylinder 2. Then, the striking piston 4 is driven. The driving screw 6 driven by the striking mechanism a is driven into the driven material 15 with a part left, and further screwed by the screw rotating mechanism b.

On the other hand, when the trigger lever 12 is released, the trigger valve 13 causes the head valve 14 to again close the striking cylinder 2 to the air chamber 9 and open to the exhaust port as shown in FIG. The pressure on the upper surface of 4 is reduced, and the pressure on the lower surface is increased by the action of the compressed air that is compressed by the striking piston 4 at the time of driving and stored in the blowback chamber 16, and the differential pressure between the upper and lower surfaces of the striking piston 4 is reversed. Therefore, the striking piston 4 returns to the top dead center.

The screw rotating mechanism b is the output shaft 1 of the air motor 7.
The rotation of No. 7 is transmitted to the drive gear 19 via the intermediate gear 18, and the bit 3 inserted into the non-circular through hole at the center of the drive gear 19 is rotated. The air motor 7 and the striking cylinder 2 are connected by an air passage 20 and are configured to rotate using the compressed air supplied into the striking cylinder 2. The air passage 20 is formed so as to communicate with the air introduction portion 20b of the air motor 7 from the striking cylinder 2 through the passage 20a. Therefore, after the striking mechanism a is actuated, the screw rotation mechanism b is actuated by the compressed air supplied from the air passage 20, and the driven material 1 is driven from the state of FIG.
The driving screw 6 driven in 5 is screwed in.
The bit 3 is slidable in the axial direction with respect to the drive gear 19 and is inserted so as to rotate together with the drive gear 19.

By the way, the screw feeding air cylinder device 1
As shown in FIG. 1 and FIG. 4, reference numeral 1 denotes a feed piston 23 which is slidably accommodated in a cylinder 22.
To the support shaft 25 at the tip of the feed rod 24 connected to the feed claw 2
6 is rotatably attached, the feed piston 23 is constantly urged toward the feed side by the spring 27, and compressed air is supplied from the feed hole 28 formed in the cylinder 22 to feed the feed piston 23 by one screw. It is configured to move backward. The supply hole 28 communicates with the blowback chamber 16 via an air passage (not shown),
The compressed air stored in the blowback chamber 16 at the time of driving is supplied to the cylinder 22 from the supply hole 28, and the feed claw 26 moves backward. After the driving is completed, the compressed air is discharged from the blowback chamber 16 and at the same time the compressed air supplied to the cylinder 22 is also discharged. Therefore, the feed piston 23 is actuated in the feeding direction by the force of the spring 27, and the driving screw is It is supplied to the nose section 5. Therefore, the feed piston 23 is normally positioned at the feed end by the spring 27.

Reference numeral 21 indicates a contact arm. The contact arm 21 is slidable along the nose portion 5 and is provided so as to be pushed (relatively moved upward) to the body 1 side by pressing the tip of the contact arm 21 against the material 15 to be driven. So contact arm 2
The upper end of 1 moves upward to make the pulling operation of the trigger lever 12 effective (to operate the trigger valve 13), and constitutes the same safety device as that of a normal nailer. The lower end of the contact arm 21 has a nose portion 5
Is formed in a cylindrical shape so as to surround the.

In addition to the above-mentioned function as a safety device, the contact arm 21 has the tip of the bit 3 after actuation so that the entire screw is not driven into the driven material 15 at the time of driving. It also has a function of stopping at a position above the surface of the above and driving it with the head of the driving screw 6 floating. Therefore, the contact arm 21 is configured to slide in two steps. At the first step, release the safety device and drive with the screw head raised (see Fig. 2).
A lock mechanism that locks the contact arm 21 at the moving end of the first-stage movement is provided. Then, by releasing the lock mechanism after the end of the impact, the second stage of the contact arm 21 can be moved and screwed.

As shown in FIGS. 3 (a) and 4, the lock mechanism c is formed by engaging and disengaging the lock piece 30 interlocking with the screw feed air cylinder device 11 with the tubular portion 31 of the contact arm 21. The lock piece 30 is rotatably attached to the support shaft 25 of the feed rod 24 of the screw feeding air cylinder device 11, and is biased by the spring 32 in one direction. The feed piston 23 is normally positioned at the feed end by the spring 32. In this state, the tip of the lock piece 30 is located at the upper end edge 31a of the tubular portion 31 at the lower end when the contact arm 21 moves upward. Engage and contact arm 21
It is formed to lock the movement of the first stage.
When the feed piston 23 moves in the feed direction, the tip of the lock piece 30 collides with the arm portion of the contact arm. At this time, the lock piece 30 rotates about the support shaft 25 against the spring 32. Escape to the side (direction of arrow A in Fig. 4),
It does not hinder the movement of the feed claw 26.

On the other hand, when the striking mechanism a is operated based on the ON signals from the trigger valve 13 and the head valve 14, as shown in FIG.
The compressed air stored therein is supplied to the cylinder 22 of the screw feeding air cylinder device 11 and the locking piece 30 moves backward together with the feeding claw 26, so that the contact arm 21
And the lock mechanism c is released.

In the above construction, when the driving screw 6 is driven, the lower end of the contact arm 21 is pressed against the driven material 15 as shown in FIG. 2, so that the contact arm 21 is relatively locked by the locking mechanism c. Slide upward (to the body 1 side) to the step position (the position indicated by the dotted line in Fig. 3 (a)). This sliding makes the pulling operation of the trigger lever 12 effective. Then, the striking mechanism a is operated by pulling the trigger lever 12, the striking piston 4 is driven, and the driving screw 6 is driven with the head lifted. Then, when the striking piston 4 is driven, the air in the blowback chamber 16 is compressed and further supplied to the feed air cylinder device 11 as shown in FIG. 3 (b) so that the feed piston 23 resists the spring (27). Move backward. As a result, the lock piece 30 also retracts, so that the engagement with the upper edge 31a of the tubular portion 31 of the contact arm 21 is released, and the contact arm 21 is further moved to the body 1.
It becomes possible to move to the side.

By the way, a part of the compressed air supplied into the striking cylinder 2 at the time of driving is supplied to the air motor 7 to drive the screw rotating mechanism b. This makes bit 3
Rotates and engages with the head groove of the driving screw 6 to rotate, so that the driving screw 6 is screwed into the driven material 15. The lock mechanism c is released by the compressed air in the blowback chamber 16, whereas the screw rotation mechanism b is operated by the compressed air in the striking cylinder 2, but the lock mechanism c is released more easily. Done early.

When the trigger lever 12 is released after the screwing is completed, the striking piston 4 returns to the initial position and the compressed air stored in the blowback chamber 16 is also discharged, so that the feed piston 23 of the air cylinder device 11 is discharged. As shown in FIG. 3 (a), the screw 27 is fed by the spring 27, and the lock piece 30 of the lock mechanism c moves to a position where it engages with the contact arm 21.

As described above, the driving of the driving screw 6 by the driving machine is performed by operating the locking mechanism c and releasing the safety device, driving operation by the striking mechanism, and locking mechanism c.
After that, the driving screw 6 is driven, the lock mechanism c of the contact arm 21 is released, and the bit 3 engages with the head groove of the driving screw 6. Since the bit 3 is configured to rotate, it is possible to effectively prevent the driving screw 6 from coming out of the driving screw 6.

In addition, if the contact arm 21 is unlocked before the air motor 7 is rotated based on the turning on of the signal for operating the striking mechanism,
It is not limited to the above example. For example, the locking mechanism c may be any structure as long as it can lock the contact arm at the first stage, and is not the screw feed air cylinder device as described above,
An air cylinder device other than this may be used. Also,
The signature of the release of the lock mechanism c is the blowback chamber 1
It is not limited to the compressed air in 6. Compressed air in the cylinder chamber, head valve valve or trigger valve may be used, or compressed air of a system independent of these may be used.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a driving machine according to the present invention.

FIG. 2 is an explanatory view of an operation mode when the striking mechanism of the driving machine is operated.

3 (a) and 3 (b) are explanatory views of an operation mode of a lock mechanism.

FIG. 4 is a perspective view of a main part of a lock mechanism of a contact arm.

[Explanation of symbols] [Explanation of symbols]

 a striking mechanism b screw rotating mechanism c locking mechanism 1 body 2 striking cylinder 3 bit 4 striking piston 5 nose part 7 air motor 21 contact arm

Claims (1)

[Claims] 1. A striking piston having a screw driving bit is slidably housed vertically in a striking cylinder provided in a body, compressed air is supplied into the striking cylinder, and the striking piston is used to supply the compressed air. Equipped with a striking mechanism that strikes a driving screw in the nose part provided at the tip of the body and drives it until its head is lifted up, and a screw rotating mechanism that screws in the driving screw driven by the striking piston by an air motor. In the driving machine, the contact arm, which is slidable along the above nose part and is pushed into the body side by pressing the tip of the tip against the driven material, cannot slide in the middle of the movement range. A lock mechanism for locking is provided, and the air motor There bit off prevention mechanism in striking turning machine drive screw, characterized in that to release the locking mechanism before the rotation.