JP3301071B2 - Piston structure in pneumatic nailing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston structure in which a driver for hitting a nail is connected to a hitting piston constituting the hitting mechanism in a nail driving machine for driving a nail hitting mechanism by air pressure.

[0002]

2. Description of the Related Art Generally, a striking mechanism of a pneumatic nailing machine accommodates a striking piston provided with a nail driving driver in a striking cylinder so as to be slidable up and down, and supplies compressed air into the striking cylinder to form the striking piston. It is configured to be driven. In a conventional nailing machine, a driver 30 is screwed into a striking piston 31 and bonded and fixed, as shown in FIG. 5 (a), or the driver 30 is mounted as shown in FIG. 5 (b). A structure is adopted in which the piston is attached to the center hole of the striking piston 31 through the hole 32.

[0003]

However, in any of the above cases, since the striking piston 31 and the driver 30 cannot be disassembled, it is not possible to replace only the driver 30 when the driver 30 is worn. In the former structure, the driver 30 rotates together with the striking piston 31 after striking in the driving machine. At the time of striking, the lower end of the striking piston 31 is pressed against the bumper 34 by high-pressure compressed air supplied into the striking cylinder 33. And
Further, since the upper end of the driver 30 is pressed against the striking piston 31, the rotational resistance between the striking piston 31 and the driver 30 is large, and the driving force for rotation must be increased. On the other hand, according to the latter structure, the driver 30 itself rotates. However, the structure is complicated, so that the cost is increased, and since the driver 30 is integrally fixed via the bearing 32, the driver 30 can be easily replaced. Can not.

The present invention solves the above problems, and provides a piston structure in a pneumatic nailing machine in which a striking piston and a driver can be disassembled and a rotating driver can reduce the rotational resistance. That is the subject.

[0005]

In order to solve the above-mentioned problems, a piston structure in a pneumatic nailing machine according to the present invention comprises a hammering piston having a nailing driver in a hammering cylinder slidably up and down. Then, in a pneumatic nailing machine in which compressed air is supplied into a striking cylinder to drive the striking piston to drive a nail, the striking piston is formed so as to be able to be divided from upper and lower piston members, and a lower surface center of an upper piston member is formed. The convex portion at the center of the upper surface of the lower piston member is fitted into the concave portion of the portion, the driver is made to pass through the center of the lower piston member, and the flange formed so as to project outward from the upper end portion of the driver is formed on the bottom surface of the concave portion. Receiving convex part
And the inner surface of the recess
Is provided so as to pass laterally through the boundary between
The upper and lower piston members are connected and fixed by the two fixed pins.

The pneumatic nailing machine is a driving machine which drives a driving screw after driving a driving screw with a bit in place of the driver, and the bit is provided rotatably about an axis with respect to a hitting piston. Configuration.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a driving machine for driving a driving screw. This driving machine moves a striking piston 4 having a striking bit 3 in a striking cylinder 2 inside a body 1 up and down. Slidably housed in the impact cylinder 2
The driving piston 4 is driven by supplying compressed air to the inside thereof, and a driving mechanism a of a driving screw 6 for driving a driving screw 6 in a nose portion 5 provided at a tip of the body 1 by a bit 3 by a bit 3, and an air motor 7. And a screw rotating mechanism b for screwing the driving screw 6 hit by the driving of the hitting piston 4.

The compressed air is supplied from a compressed air supply source (not shown) into the striking cylinder 2 through a grip 8 and an air chamber 9 formed in the body 1.

The striking mechanism a is operated by pulling the trigger lever 10. The trigger valve 11 is actuated by the trigger lever 10, and the head valve 12 is opened upward in conjunction with the trigger valve 11 to actuate, thereby instantaneously supplying high-pressure compressed air in the air chamber 9 to the striking cylinder 2 and striking. The piston 4 is driven. As a result, as shown in FIG. 2, the driving screw 6 driven by the driving mechanism a is driven into the material to be driven except for a part thereof, and further driven by the screw rotating mechanism b.

On the other hand, when the trigger lever 10 is released, the head valve 12 is operated by the trigger valve 11 to close the striking cylinder 2 to the air chamber 9 and open to the exhaust port 13, so that the pressure against the upper surface of the striking piston 4 is reduced. And the pressure on the lower surface is increased by the action of the compressed air stored in the blowback chamber 14 by being compressed by the striking piston 4 at the time of driving, and the differential pressure on the upper and lower surfaces of the striking piston 4 is reversed. Returns to top dead center.

The screw rotation mechanism b transmits the rotation of the output shaft of the air motor 7 to the drive gear 16 via the intermediate gear 15 and rotates the bit 3 inserted through the non-circular through hole at the center of the drive gear 16. It is. Bit 3 is the driving gear 1
6 is slidable in the axial direction, and is inserted so as to rotate with the drive gear 16. The air motor 7 may be operated by utilizing a part of the compressed air supplied to the striking cylinder 2.

The driving screw 6 is connected via a connecting member (not shown) and is housed in a magazine 17 in a coil shape. Then, the screws are supplied one by one into the nose portion 5 by the screw feed cylinder device 18.

The striking piston 4 constituting the striking mechanism a is formed so as to be divided into upper and lower piston members 4a and 4b as shown in FIGS. A concave portion 18 is formed in the center of the lower surface of the upper piston member 4a,
An O-ring 19a is attached to the outer peripheral surface. The lower piston member 4b is provided with a convex portion 20 which fits into the concave portion 18 at the center of the upper surface, and a bit through hole 21 is formed at the center. A large-diameter flange receiving portion 22 is formed above the through hole 21, and an O-ring 19 b
Is attached.

The lower end of the bit 3 is formed so as to engage with the head groove of the driving screw 6, and the upper end thereof is formed with a flange 23 projecting outward.

The bit 3 penetrates through the central through hole 21 of the lower piston member 4b, and the flange 23 is accommodated in the receiving portion 22. In this state, the projection 2 of the lower piston member 4b is
0 is fitted into the recess 18 of the upper piston member 4a.
The flange 23 of the bit 3 has a washer 24 (upper piston 4
a for preventing abrasion of the upper piston member 4a) and in the space between the bottom surface of the concave portion 18 of the upper piston member 4a and the receiving portion 22 of the convex portion 20 of the lower piston member 4b. Further, the upper piston member 4a and the lower piston member 4b are connected by a fixing pin 25. The bit 3 is configured to be rotatable around the axis while being supported by the through hole 21 of the lower piston member 4b with respect to the striking piston 4.

According to the piston structure, the high-pressure compressed air supplied into the striking cylinder 2 at the time of striking acts on the upper surface of the striking piston 4, and the lower surface of the striking piston 4 is
6, the upper and lower surfaces of the striking piston 4 receive large resistance. However, compressed air is received on the upper surface of the upper piston member 4a, and the bit 3 itself is not affected by the compressed air. The rotation resistance of the striking piston 4 does not affect the rotation of the bit 3 itself. Therefore, when the bit 3 is rotated by the rotation mechanism, it rotates with a small rotation resistance. Therefore, the rotational driving force can be reduced.

Further, since the bit 3 is mounted without the intervention of a bearing or the like, the structure is simple and the manufacturing cost can be reduced.

Further, since the upper piston member 4a and the lower piston member 4b can be easily separated by pulling out the fixing pin 25, when the bit 3 is worn out, it can be replaced with a new one.

The piston structure is not limited to the driving machine described above, but can be applied to a piston structure of a pneumatic nailing machine which drives a normal nail instead of a driving screw. In this case, the bit replaces the driver, and the driver need not be rotatable with respect to the striking piston.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a nailing machine (driving machine) according to the present invention.

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

FIG. 3 is a sectional view of a main part of a piston structure of the nailing machine.

FIG. 4 is an exploded view of the main part.

5 (a) and 5 (b) are cross-sectional views of main parts of a conventional piston structure.

[Explanation of symbols]

 a striking mechanism b screw rotating mechanism 2 striking cylinder 3 bit 4 striking piston 4a upper piston member 4b lower piston member 23 flange

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noboru Ishikawa 6-6 Nihonbashi Hakozakicho, Chuo-ku, Tokyo Inside Max Co., Ltd. (72) Inventor Takeo Fujiyama 6-6 Nihonbashi Hakozakicho, Chuo-ku, Tokyo Max (56) References JP-A-6-79644 (JP, A) JP-A-6-62373 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B25C 1/04

Claims (2)

(57) [Claims] 1. A pneumatic nail in which a striking piston provided with a nail driving driver is slidably housed vertically in a striking cylinder, and compressed air is supplied into the striking cylinder to drive the striking piston to drive the nail. In the percussion machine, the impact piston is formed so as to be separable from upper and lower piston members, and a projection at the upper center of the lower piston member is fitted into a recess at the lower center of the upper piston member. Pass the driver through and fit a flange formed outwardly from the upper end of the driver to the bottom of the recess.
And the boundary between the inner surface of the concave portion and the outer surface of the convex portion is arranged in the space between the surface and the receiving portion of the convex portion.
A piston structure in a pneumatic nailing machine, wherein upper and lower piston members are connected and fixed by two fixing pins provided so as to pass in the directions . 2. The pneumatic nailer according to claim 1, wherein said pneumatic nailing machine is a driving machine which drives a driving screw after driving a driving screw with a bit in place of said driver, and said bit is rotatably provided around an axis with respect to a hitting piston. The piston structure in a pneumatic nailer according to claim 1, wherein: