JPH0351111Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a shock absorber for a striking piston in a nailer driven by compressed air. This relates to a damping device for a piston in a tool that is mounted eccentrically with respect to a line.

(Prior art) In a general nail gun that uses compressed air as a driving source, the percussion driver that drives the nail from the tool is installed concentrically with the percussion piston on the center line of the piston. The punching position is configured to be spaced a predetermined distance from the front edge of the tool. Therefore, when driving nails into corners such as walls, there is a problem that the front edge of the tool hits the wall and the nail driving position cannot be set in the corner, making it impossible to drive nails into the corner. Ta.

Therefore, as shown in, for example, U.S. Patent No. 3043272 and Japanese Patent Publication No. 56-8754, the driving position of the nail can be adjusted by making the nail driving driver eccentric from the center line of the driving piston toward the front of the tool. A new tool has emerged that allows nailing into corners by setting the tip closer to the front edge of the tool.

(Problems with the prior art) In the above-mentioned prior art, by mounting the percussion driver eccentrically from the center of the piston,
The center of gravity of the striking piston, including the striking piston, will be biased in the direction in which the driver is attached.

However, in the tool shown in the above-mentioned U.S. patent, the shock-absorbing member that buffers the impact of the striking piston is provided only in the portion that faces the lower surface of the piston in the direction opposite to the eccentric direction of the driver. The eccentric side of the driver is displaced further downward, causing the piston to tilt in the cylinder and change the angle with the driver. As a result, stress is concentrated on the attachment portion of the driver and the piston, resulting in loss of the driver, and the actual situation is that it cannot be put to practical use.

Furthermore, the tool shown in Japanese Patent Publication No. 56-8754 avoids the above phenomenon by installing a counterweight on the side of the striking piston opposite to the eccentric direction of the driver to correct the position of the center of gravity of the striking piston. .

However, by adding weight to the striking piston, the weight of the striking piston increases, making it impossible to obtain a sufficient initial velocity of the piston, resulting in loss of output, and also becoming a factor that hinders the reduction in size and weight of tools. Ta.

(Technical Problem of the Invention) The present invention provides a shock absorber without increasing the piston weight and without tilting the striking piston in a striking tool equipped with a striking piston in which a driver is mounted eccentrically with respect to the center line of the striking piston. The purpose of the present invention is to provide a shock absorbing device that allows

(Technical Means of the Invention) In order to solve the above-mentioned problems, the present invention has a shape center position of the percussion piston at the lower end of the percussion cylinder facing the lower surface of the percussion piston whose center of gravity is eccentric from the center line. and the buffer member is formed so that the total mass of the portion facing the lower surface of the piston on the side in which the driver is eccentric is larger than the total mass of the portion facing the lower surface of the piston on the side opposite to the eccentric direction of the driver. By arranging this, it is possible to uniformly dampen the impact piston.

(Function of the invention) When a percussion piston whose center of gravity is offset from the center line of the piston due to the eccentric mounting of the percussion driver is buffered by the buffer member having the above structure, the percussion piston will move around its center of gravity. Since the front and rear portions of the shock absorbing member having the above structure are buffered by each portion of the shock absorbing member having approximately the same total mass, the striking piston receives a balanced buffering force before and after the center of gravity. It is possible to provide a nailing machine that can prevent the occurrence of tilting of the nails, and can drive nails into corners without failures such as breakage of the percussion driver.

(Embodiments of the invention) Examples of the invention shown in the drawings will be described below.

In FIGS. 1A and 1B, a compressed air nailer 1 has a percussion cylinder 10 in a housing 2, and a percussion piston 11 is slidably disposed within the percussion cylinder 10. The striking piston 11 is opened by the upward movement of the main valve 5 which is opened via the starting valve 4 by the operation of the starting device 3.
The blow cylinder 10 is impact-driven downward in the figure by compressed air introduced into the blow cylinder 10 from the air chamber 6 from the upper end of the blow cylinder 10.

A percussion driver 12 for driving a nail is integrally attached to the percussion piston 11 at a position offset from the center line by a distance L toward the front of the tool. Therefore, the nails supplied from the nail storage magazine 7 via the nail supply mechanism into the driver guide member 8 disposed below the striking cylinder 10 are driven with their tips toward the surface of the material to be driven. .

Since the percussion piston 11 is usually made of a light metal such as aluminum, and the percussion driver is made of steel, the center of gravity of the percussion piston including the percussion driver is offset by a distance G toward the front of the tool.

A buffer member 1 is provided at the lower end of the striking cylinder 10 to buffer the impact-driven striking piston 11.
3 is placed. The buffer member 13 has a circular outer peripheral surface 1 located along the inner wall of the impact cylinder 10.
3c and a through hole 13 through which the impact driver 12 can pass.
d, and the through hole 13d is formed in the outer circumferential surface 13 as shown in FIG.
A large diameter portion 13e formed concentrically with the circle c, and a small diameter circular portion 1 formed biased toward the front of the tool to accommodate the impact driver 12 mounted eccentrically.
3f. Furthermore, the buffer member 13
A chamfered portion 13g is formed on the upper and lower edges of the outer circumferential surface 13c of the cushioning member 13 so that the rear side of the tool is larger than the front side of the tool.

As a result, the buffer member 13 is located on the front side of the tool, that is, the large mass part 13a side, and on the rear side, that is, the small mass part 13b, with the center of gravity of the striking piston 11 as a boundary.
The structure is such that the total mass of each side is almost balanced. That is, considering the shape center line of the impact piston 11, the large mass portion 13 of the buffer member 13
The total mass on the a side is larger than that on the small mass portion 13b side.

With the above configuration, when the striking piston 11 is driven and the lower surface of the striking piston 11 collides with the buffer member 13 at the end of its impact stroke, the striking piston 11 is moved to the front side of its center line, that is, on the side where the center of gravity is biased. It is buffered by the large mass portion 13a having a large total mass of the member 13, and the rear side is buffered by the buffer member 13.
Since the overall mass of the impact piston 11 is damped by the small mass portion 13b having a small total mass, the overall damping effect on the impact piston 11 is balanced in the longitudinal direction of the tool with the center of gravity of the impact piston 11 as a border, and the effect of tilting the impact piston 11 is balanced. It does not occur.

Next, another embodiment of the present invention shown in FIGS. 3 and 4 will be described.

FIG. 3 shows a circular outer peripheral surface 14c disposed along the inner wall surface of the impact cylinder and the impact driver 12.
The buffer member 14 is formed in a substantially annular shape and has a circular inner circumferential surface 14d through which the inner circumferential surface 14d can pass, and the inner circumferential surface 14d has a center biased toward the rear side of the tool with respect to the center position of the circle forming the outer circumferential surface. It is formed by a circle centered on a point. Therefore, the buffer member 14 has a large mass portion 14a that is thick in the radial direction and has a large total mass on the front side of the tool with respect to its shape center line, that is, on the side where the center of gravity of the striking piston 11 is biased, and on the opposite side. That is, on the side far from the center of gravity of the striking piston 11, a small mass portion 14b is formed which is thin in the radial direction and has a small total mass.

Further, FIG. 4 shows a buffer member 15 formed in an annular shape similar to the first embodiment described above, and both the outer circumferential surface 15c and the inner circumferential surface 15d of the buffer member 15 are on the center line of the striking piston 11. It is formed of concentric circles centered on a point, and extends from the front side to the rear side of the striking piston 11 over the inner peripheral surface 15d and the upper end surface 15e, that is, from the side where the center of gravity of the striking piston 11 is biased to the opposite side. towards the side,
A chamfered portion 15f whose width gradually increases is formed. Therefore, in the buffer member 15, a large mass portion 15a having a large vertical cross-sectional area and a large total mass is formed on the front side of the tool of the shape center line, that is, on the side where the center of gravity of the striking piston 11 is biased, and on the opposite side, that is, on the side where the center of gravity of the striking piston 11 is biased. A small mass portion 15b having a small vertical cross-sectional area and a small total mass is formed on the side far from the center of gravity of the striking piston 11.

The fact that these buffer members 14 and 15 can prevent the impact piston 11 from tilting during impact buffering is the same as described in the first embodiment.

(Effects of the invention) As is clear from the above explanation, according to the invention, nailing work can be performed in corners without adding a counterweight to the percussion piston, without failures such as breakage of the percussion driver, etc. It is possible to provide a compressed air nailer capable of

[Brief explanation of the drawing]

Fig. 1 is a vertical side view of a compressed air nailing machine showing the first embodiment of the present invention, Fig. 2 is a buffer member used in the nailing machine, and A is a plan view and a longitudinal cross-section. 3 and 4 are respectively a plan view and a vertical sectional view showing a buffer member according to another embodiment of the present invention. 10...Blow cylinder, 11...Blow piston, 12...Blow driver, 13, 14, 15...
...buffer member, 13a, 14a, 15a...large mass part, 13b, 14b, 15b...small mass part.

Claims (1)

[Scope of utility model registration request] The tool includes a striking piston that is reciprocably disposed in a striking cylinder and is impact-driven by compressed air force, and a striking driver that is mounted eccentrically in the front direction of the tool with respect to the center line of the striking piston. , a compressed air nail gun comprising a buffer member disposed at the lower end of the striking cylinder facing the lower surface of the striking piston, the buffering member coming into contact with the lower surface of the striking piston to buffer the impact of the striking piston, wherein the buffering member is The total mass of the large mass part facing the lower surface of the piston in the direction in which the driver is eccentric is equal to the total mass of the large mass part facing the lower surface of the piston in the direction opposite to the eccentric direction of the driver with respect to the center position of the shape of the striking piston. A shock absorber for a pneumatically driven impact tool, characterized in that the shock absorber is formed to be larger than the total mass of the impact tool.