JPH09290376A - Contact arm mechanism for screw driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide contact arm mechanism for a screw driver prevented from becoming long in the whole length. SOLUTION: In a screw driver provided with impact mechanism for applying impact to a driving screw 5, and screw rotating mechanism for screwing the driving screw 5 into screwed material 43, a contact arm 20 is divided into an upper arm part 20a and a lower arm part 20b, and the movement of the contact arm 20 is divided into first stage movement of being pressed to the screwed material 43 until a trigger lever 9 becomes effective, and second stage movement until screw rotating mechanism is stopped. It is so formed that the upper arm part 20a and the lower arm part 20b are integrally operated during the first stage movement and that only the lower arm part 20b is operated during the second stage movement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a contact arm mechanism in a screw driving machine having a function of sensing a material to be screwed in and a function of stopping a screw rotation mechanism of a screwdriver driver bit.

[0002]

2. Description of the Related Art A screwdriver having a striking mechanism for striking a material to be screwed into a material to be screwed with a driver bit and a screw rotating mechanism for rotating the driver bit to screw the driving screw into the material to be screwed. Has
There is provided a contact arm that senses that the tip of the injection portion comes into contact with the material to be screwed and that enables the operation of the trigger lever for starting the screw driver. This contact arm is provided slidably in the driving direction on the screwdriver, and one end (lower end) of the contact arm projects further than the tip of the injection part and the other end (upper end) is located near the trigger lever. It is arranged. And the contact arm is
Since the lower end of the contact arm is moved upward relative to the screwdriver by pressing it against the material to be screwed, the upper end of the contact arm enables the trigger lever start operation to operate the striking mechanism. , Functioning as a safety device.

The contact arm also has a function of adjusting the driving depth of the driving screw by adjusting the amount of protrusion of the lower end from the injection portion. Therefore, when the predetermined driving depth is reached, the screw rotation occurs. It can also serve the function of stopping the operation of the mechanism.

In the case of performing the two functions of the safety device and the operation stop of the screw rotation mechanism by the integrated contact arm, the contact arm must operate in two stages. That is, it is necessary to enable the trigger lever starting operation at the first stage and stop the screw rotation mechanism at the second stage.

[0005]

However, if such a two-step stroke system is adopted, the range of movement of the contact arm becomes large as a whole, so that peripheral parts are especially located at the portion where the upper end of the contact arm moves. There is a drawback in that the space for escape so as not to interfere with each other must be made large, and there is a possibility that the total length becomes longer by that amount, and the trigger lever cannot be set at an appropriate position.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to provide a contact arm mechanism of a screw driving machine which does not increase the total length by dividing the contact arm into two parts.

[0007]

In order to solve the above-mentioned problems, the contact arm mechanism of the screw driving machine according to the present invention hits the driving screw supplied to the injection portion downward with the material to be screwed. A screw driving machine equipped with a striking mechanism and a screw rotating mechanism for screwing a driven screw into a material to be screwed after striking is provided with a contact arm that slides in the driving direction of the driven screw along the injection part. , The lower end of the contact arm is urged in the direction in which it projects further than the tip of the injection part that drives out the driving screw, and the lower end of the contact arm is pressed against the material to be screwed so that the trigger lever can be operated to start. In a screwdriver for moving to a valid position, the contact arm is divided into an upper arm portion and a lower arm portion. In both cases, the movement of the contact arm is divided into a first-stage movement until the trigger lever is activated by pressing the material to be screwed, and a second-stage movement until the screw rotation mechanism is stopped. It is characterized in that the upper arm portion and the lower arm portion are integrally operated during the movement, and only the lower arm portion is operated during the second stage movement.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a screw driver, which comprises a body 1, a grip 2 and a magazine 3. The driving screw 5 is configured to be supplied, and the driving screw 5 supplied to the injection portion 4 is struck by the striking mechanism in the body 1 to drive a part of the driving screw 5 into the material to be screwed, and then the magazine The driving screw 5 hit by the screw rotating mechanism arranged on the upper part of 3 is rotated and screwed into the material to be screwed.

In the striking mechanism, a striking piston 7 slidably arranged in a striking cylinder 6 is integrally connected with a striking bit 8, and a trigger valve 10 and a main valve 11 are actuated based on a starting operation of a trigger lever 9. The air chamber 12
The compressed air filled in the striking cylinder 6 is supplied into the striking cylinder 6 to drive the striking bit 8 together with the striking piston 7 to strike the driving screw 5 in the injection section 4.

At the time of striking, the air on the lower surface side of the striking piston 7 is compressed and supplied to the blowback chamber 13. This compressed air is used to move the striking piston 7 upward with the release of the trigger lever 9 and to operate the screw feed cylinder device described later. The striking mechanism and various valves, trigger levers, screw feed cylinder devices, and the like associated therewith are known mechanisms known in conventional nail driving machines.

The screw rotation mechanism uses an air motor 14 as a drive source, and an output shaft 15 of the air motor 14 is meshed with a bevel gear 16, an intermediate gear 17, and a drive gear 18, so that the drive gear 1
The driving bit 8 is fitted into a non-circular through hole 19 provided in the center of the driving hole 8, and the driving bit 8 is rotationally driven by the rotation of the air motor 14.

Next, the screw driving machine is provided with a contact arm 20. The contact arm 20 is provided so as to be slidable in the screw driving direction along the injection portion 4, its lower end is biased so as to project downward from the tip of the injection portion 4, and the lower end is pressed against the material to be screwed. As a result, the upper end of the contact arm 20 is moved to a position where the starting operation of the trigger lever 9 is effective.

As shown in FIG. 2, the contact arm 20 is divided into an upper arm portion 20a and a lower arm portion 20b. The upper arm portion 20a is a plate-like member, and is bent and formed in two steps. The lower arm portion 20b includes a rod portion 21 bent in three steps and a head portion 2 formed at the lower end thereof.
2 and. The head portion 22 projects below the ejection portion 4. The lower arm portion 20b is constantly urged downward by the first spring 23 provided between the head portion 22 and the body 1. The opening 2 through which the upper end of the lower arm portion 20b passes is formed at the lower end of the upper arm portion 20a.
4 is formed, and a second spring 26 is arranged between the peripheral edge of the opening 24 and the protrusion 25 formed in the middle of the lower arm 20b, and always urges the upper arm 20a upward. are doing.

The upper end of the upper arm portion 20a is engaged with one end of a coiled spring 28 wound around a shaft 27 on the side surface of the trigger lever 9. The other end of the spiral spring 28 is engaged with an operating plate 29 rotatably attached to the shaft 27. A part of the outer peripheral edge of the actuation plate 29 is formed in an arc shape, and normally the edge closest to the shaft 27 faces the valve stem 30 of the trigger valve 10 as shown in FIGS. 1 and 2. At this time, even if the trigger lever 9 is pulled, the valve stem 30 cannot be pushed in, so the operation is invalid. On the other hand, by pushing up one end of the coiled spring 28, the edge of the actuating plate 29 farthest from the shaft 27 rotates so as to face the valve stem 30 (see FIG. 3), so that the trigger lever 9 is pulled. The valve stem 30 is effectively pushed in by the start operation.

By the way, a stop valve 31 and a screw feed cylinder device 32 are provided in connection with the operation of the contact arm 20.

The stop valve 31 has a lower arm portion 20b.
A valve 34 that opens and closes the air supply passage 33 and a valve stem 35 that opens and closes the air supply passage 33, which is disposed in the middle of an air supply passage 33 that supplies compressed air to the air motor 14. In addition, a push button 36 that operates together with the valve stem 35 is arranged. The push button 36 projects below the valve housing 37. The upper end of the lower arm portion 20b is arranged so as to face the push button 36 protruding below the stop valve 31.

The screw feed cylinder device 32 is shown in FIG.
As shown in FIG. 2, it is arranged on one side of the magazine 3. A piston rod 40 is slidably provided on the screw feed cylinder 39, and the piston rod 4 protruding outward is provided.
A feed claw 41 is attached to the tip of 0, and the feed claw 41 is spring-biased so as to project to the front position. The feed claw 41 is retracted by the compressed air supplied from the blowback chamber 13, and the feed claw 41 is moved forward by the exhaust of the compressed air to supply the driving screw 5 in the magazine 3 to the ejection unit 4. A stopper plate 42 is attached to the tip of the piston rod 40 together with the feed pawl 41. This stopper plate 42 is used for the feed claw 4
When 1 is at the front end position, it is set to engage with the upper end 22a of the head portion 22 below the contact arm 20. Therefore, the contact arm 20 moves to a position where the head portion 22 engages with the stopper plate 42 when the stopper plate 42 is at the front position (first position).
When the stopper plate 42 retreats, the stopper plate 42 can further move to the upper side (second step movement). When the second stage is moved, the lower arm portion 20
The upper end of b is configured to push the push button 36 of the stop valve 31.

In the above structure, when the driving screw 5 is screwed in by the screw driving machine, the head portion 22 at the lower end of the contact arm 20 is first pressed against the screwed material 43 as shown in FIG. As a result, the first spring 2
The lower arm portion 20b rises relative to the body 3 relative to the body 1. At this time, since the stopper plate 42 of the screw feed cylinder device 32 is at the front position, the contact arm 20 stops at the first stage movement. Lower arm part 2
0b, the upper arm portion 20a is integrally moved upward by the second spring 26, so that the upper end pushes up the coil spring 28 of the trigger lever 9 to rotate the operating plate 29. After that, the trigger valve 10 of FIG. 1 is effectively pushed in only by pulling the trigger lever 9, the striking mechanism of the screw driving machine is actuated, and the driving screw 5 in the injection section 4 is driven out, and a part of it is covered. It is driven into the screw material 43. Subsequently, the air motor 14 is actuated by a signal when the striking mechanism is actuated, the drive gear 18 is rotated, and the hammering bit 8 is rotated.
Are screwed into the material 43 to be screwed.

When the striking mechanism is operated, the compressed air on the lower surface side of the striking piston 7 is supplied to the blowback chamber 13 to be filled therethrough, and further passes through a pipe (not shown) while the air motor 14 is actuated. Is supplied to the screw feed cylinder device 32 to operate the feed pawl 41. This causes the stopper plate 42 to retract, so that the contact arm 20 is disengaged from the head portion 22 and the contact arm 20 moves to the second stage movement. Then, as the driving screw 5 is screwed in,
The lower arm portion 20b relatively rises against the second spring 26. At this time, the upper arm portion 20a does not move upward. When screwed to a predetermined screwing depth, the upper end of the lower arm portion 20b pushes the push button 36 of the stop valve 31, so the valve stem 30 of the stop valve 31 is pushed in, and the air in the space 44 (see FIG. 3) is removed. It is discharged and the valve 34 moves downward. As a result, the air supply passage 33 leading from the air chamber 12 to the air motor 14 is blocked, the operation of the air motor 14 is stopped, and the screwing is completed.

After that, the screw driving machine is set to the threaded material 4
By releasing the trigger lever 9 away from 3, the contact arm 20 moves integrally to the original lower position with respect to the body 1 and the valve stem 3 of the stop valve 31.
5 also moves down by the spring, and compressed air collects in the space 44, so that the air pressure causes the valve 34 to rise and return to the state of FIG. At the same time, the spring force wins with the exhaust from the blowback chamber 13 and the screw feed cylinder device 3
The second feed claw 41 moves forward to the state shown in FIG.

As described above, the contact arm 20 has two
It is divided and moves as a unit at the first stage movement,
Since only the lower arm portion 20b moves and the upper arm portion 20a does not move during the second stage movement, the total length of the screwdriver does not become long.

Further, since the upper arm portion 20a does not operate during the second stage movement, the trigger lever 9 can be held at a predetermined position.

The screw rotating mechanism is not limited to the air motor 14. Any other structure may be used as long as it is a mechanism for rotating the driving screw 5. Therefore, the lower arm 2
0b is also a stop valve 31 that opens and closes the air supply passage 33.
Is not limited to those that operate.

[Brief description of drawings]

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

FIG. 2 is an explanatory view showing a contact arm mechanism of the screw driving machine.

FIG. 3 is an operation explanatory diagram when the contact arm moves to the first stage.

FIG. 4 is an operation explanatory diagram when the contact arm moves to the second stage.

[Explanation of symbols]

 4 Injection part 5 Driving screw 9 Trigger lever 20 Contact arm 20a Upper arm part 20b Lower arm part

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takeo Fujiyama 6-6 Nihonbashi-Hakozakicho, Chuo-ku, Tokyo Max Co., Ltd. (72) Inventor Koji Tanaka 6-6 Nihonbashi-Hakozaki-cho, Chuo-ku, Tokyo Max Incorporated (72) Inventor Kazuhiko Kuraguchi 6-6 Nihonbashi Hakozakicho, Chuo-ku, Tokyo Max Co., Ltd. (72) Inventor Shinobu Iino 6-6 Nihonbashi Hakozakicho, Chuo-ku, Tokyo Max Co., Ltd.

Claims (1)

[Claims] 1. A striking mechanism for striking a driving screw supplied to an injection part toward the lower side of a material to be screwed, and a screw rotating mechanism for rotating the driving screw after striking and screwing the screw into the material to be screwed. The screw driving machine is provided with a contact arm that slides in the driving direction of the driving screw along the injection part, and the contact arm is attached in the direction in which the lower end of the contact arm projects ahead of the tip of the injection part that drives the driving screw. In the screwdriver in which the upper end of the contact arm is moved to a position where the starting operation of the trigger lever is enabled by pressing the lower end against the material to be screwed, the contact arm is divided into an upper arm part and a lower arm part. While dividing the contact arm into two parts, push the contact arm movement against the material to be screwed to enable the trigger lever. The first stage movement and the second stage movement until the screw rotation mechanism is stopped are further divided, and the upper arm portion and the lower arm portion are integrally operated during the first stage movement, and the second stage movement is performed. The contact arm mechanism of the screw driving machine is characterized in that only the lower arm portion is operated in the case of.