JPH07156075A - Fastener striking tool - Google Patents

Abstract

PURPOSE:To provide a fastener striking tool which is able to fully absorb the impact even if a rigit bumper being high in strength is used. CONSTITUTION:In this fastener striking tool, an upper part of this bumper 16 is annularly projected toward the underside of a piston 6, while a ring hollow 24, where an upper projection 23 of the bumper is fitted in, is formed on a bumper contact surface of the piston 6, and this bumper upper projecting 23 is closely fitted in the ring hollow 24 in a state that air lying between the hollow and the bumper projection is compressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hitting tool for a fastener such as a nailing machine, and more particularly, it absorbs a shock caused by a sudden lowering or returning of a piston to improve the durability of a bumper and suppress a hitting sound. A fastener impact tool.

[0002]

2. Description of the Related Art A pressurized air is supplied to a housing, a cylinder is provided inside the housing, and a piston having a striking member attached therein is reciprocally arranged inside the cylinder to pressurize from the upper portion of the cylinder. When air is supplied, the piston rapidly descends and hits the fastener with the striking member at the nose to the object, and then when the air above the cylinder is exhausted to the atmosphere, pressurization of the return air chamber Air is applied to the lower surface of the piston so that the piston returns to the upper part of the cylinder, and a bumper that absorbs the shock caused by the sudden lowering of the piston is provided on the lower surface of the cylinder. It is widely used at construction sites.

[0003]

In the conventional fastener impact tool, when a soft bumper is used, shock absorption is improved, but durability is weak, and conversely, when a hard bumper having high strength is used, durability is improved. Although it goes up, the shock absorption becomes low, the shock is transmitted to the entire tool, the shock is transmitted to the hands of workers, a large impact sound is generated, and the damage to the parts of the tool is accelerated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fastener hitting tool capable of sufficiently absorbing an impact even when a hard bumper having high strength is used. Another object of the present invention is to provide a fastener striking tool capable of absorbing the shock caused by the rapid return of the piston.

[0005]

To achieve the above object, according to the present invention, pressurized air is supplied to a housing, a cylinder is provided inside the housing, and a striking member is provided inside the cylinder. When the attached piston is reciprocally arranged and pressurized air is supplied from the upper part of the cylinder, the piston rapidly descends and the striking member strikes the fastener with the nose to the object, then the cylinder. When the air in the upper part is exhausted to the atmosphere, the pressurized air in the return air chamber formed between the cylinder and the housing acts on the lower surface of the piston to return the piston to the upper part of the cylinder. A bumper that absorbs impact due to the abrupt lowering of is a fastener striking tool provided on the lower end side of the cylinder, and the upper portion of the bumper is
The piston protrudes annularly toward the lower surface of the piston, and an annular recess into which the upper protruding portion of the bumper is fitted is formed on the bumper contact surface of the piston, and the upper protruding portion of the bumper is formed in the annular recess. There is provided a fastener striking tool characterized in that air between the recess and the bumper protruding portion is tightly fitted in a compressed state.

Further, according to the present invention, a cushion protruding annularly or a second annular recess into which the protruding portion of the cushion is fitted is formed at a position facing each other on the exhaust seal above the cylinder and the upper surface of the piston. ,
A fastener striking tool is provided, wherein the cushion is received in the second annular recess in a state in which air between the second annular recess and the cushion is compressed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fastener striking tool according to the present invention will be described below with reference to the drawings. In FIG. 1, a fastener hitting tool (typically a nailing machine) 1 includes a housing 3 in which a handle 2 is integrally formed, and pressurized air is supplied to the housing 3 from the handle 2 side. A cylinder 4 is provided inside the housing 3, and a piston 6 to which a striking member 5 is attached is reciprocally arranged inside the cylinder 4. A main valve 7 is provided at the upper end of the cylinder 4, and the main valve has a stationary position (a position on the left side of the axis x) that seals the upper end of the cylinder 4 and does not supply the pressurized air in the housing 3 into the cylinder. , A striking position where the seal at the upper end of the cylinder 4 is released and pressurized air is supplied from the housing 3 (axis x
The position on the right side). In the rest position, the piston 6 rests on top of the cylinder 4. At the striking position, the pressurized air is supplied to the upper part of the piston 6 through the gap between the main valve 7 and the upper end of the cylinder 4 as indicated by the arrow 9, and the piston 6 is strongly and rapidly pushed downward.

By this pressing, the striking member 5 strikes the fixing tool on the nose 10 and strikes the object such as a plate. At the time of this driving, at the same time, pressurized air is supplied to the return air chamber 11 formed between the lower part of the cylinder 4 and the housing 3 on the outer periphery of the cylinder. While the descending piston 6 is still at the upper part of the cylinder, the air below the piston 6 is allowed to flow through the intermediate hole 12 of the cylinder 4 and the hole 1 at the lower end.
3 is stored in the return air chamber 11 through 3 and the piston 6 passes through the intermediate hole 12, not only the air below the piston is supplied through the hole 13 on the lower end side, but also the pressurized air in the cylinder chamber above the piston is newly supplied. It is supplied through the intermediate hole 12. Since the O-ring 14 as a check valve is provided in the intermediate hole 12, backflow from the intermediate hole 12 to the cylinder side does not occur, and the return air chamber 11
A sufficient amount of pressurized air is stored in the. Therefore, when the main valve 7 returns to the rest position (the position on the left side of the axis x), the air in the upper part of the cylinder is exhausted to the atmosphere, and the pressurized air in the return air chamber 11 passes through the hole 13 on the lower end side to the cylinder below the piston. The compressed air flows into the chamber and acts on the lower surface of the piston 6 so that the piston 6 returns to the upper portion of the cylinder 4. A bumper 16 is provided at the lower end side of the cylinder to absorb the shock caused by the sudden lowering of the piston 6. Further, the piston 6 is provided with an O-ring 17 which forms a seal with the cylinder 4.

The main valve 7 is controlled by a trigger device 18 provided at the base of the handle 2. When the trigger valve pin 19 is in the rest position without being pushed, the pressurized air that has passed through the trigger device 18 enters the main valve chamber 21 through the pipe 20 shown by the broken line, and the main valve 7 is pushed downward and is shown in the figure. It is in a stationary position. No pressurized air is supplied to the cylinder 4, and no pressurized air is sent to the upper surface of the piston 6. Next, when the trigger valve pin 19 is pushed up, the air in the main valve chamber 21 is exhausted to the atmosphere through the trigger device 18, and the force for pushing down the main valve 7 is lost, so the main valve 7 is pushed up and the axis x. Is moved to the striking position on the right side of, and the pressurized air is supplied to the upper portion of the piston 6 as indicated by an arrow 9, and the piston 6 is strongly pushed downward so that the striking member 5 strikes the nose fixture to the object. Put in. When the trigger valve pin 19 is released, it returns to its original position and the main valve 7 returns to the rest position on the left side of the axis x. That is, since the pressurized air is no longer supplied to the upper surface side of the piston 6 that has been pushed down and is communicated with the exhaust passage to the atmosphere, the action of the pressurized air from the return chamber 11 causes the piston 6 to move. The cylinder 4 rapidly rises from its bottom dead center,
It reaches the top dead center in the figure.

The piston 6 rapidly descends to the lower end side of the cylinder 4 in order to drive the fastener into the object. In order to stop this piston 6 while absorbing the impact, the bumper 1
6 is mandatory. The bumper 16 is arranged on the lower end side of the cylinder 4 and is formed in a donut shape provided with a hole through which the striking member 5 passes, so that a shock due to a sudden downward collision of the piston 6 is generated around the entire circumference thereof. Absorb across. If you use a soft bumper, shock absorption will improve,
The durability of the bumper becomes low, the deformation becomes large, and the bumper may be plastically deformed or may generate heat and be damaged. On the other hand, if a hard bumper with high strength is used, the durability will increase, but the impact absorption will be low, and the impact will be transmitted to the entire tool, and the impact sound will be transmitted to the worker's hand etc. and the impact sound will be generated. It may also accelerate the damage of the parts.

Therefore, in the present invention, as the bumper itself, a hard rubber having a certain degree of strength is used to improve durability, and a bumper and a piston are devised to absorb a shock. In FIGS. 1 and 2, the upper portion of the bumper 16 projects annularly toward the lower surface of the piston 6 and is formed as an annular upper projecting portion 23. On the other hand, on the bumper contact surface on the lower surface of the piston 6,
An annular recess 24 is formed to receive the upper protruding portion 23 of the bumper 16. The size of the recess 24 is smaller than the depth of the inlet portion 25 (upper side in the drawing), and the upper protruding portion 23 is press-fitted in a close-fitting manner. By being formed in this way, the piston 6
When is lowered, first, the piston 6 on the right side of the axis line x in FIG.
As shown in, the inlet portion 25 of the annular recess 24 contacts the annular upper protruding portion 23 of the bumper 16 to trap the air in the recess 24 therein. The piston 6 is the protruding portion 23 as it is.
Is strongly lowered so as to receive the recess 24. This downward force is strong enough to hit a nail or the like as described above, and as shown on the left side of the axis x in FIG. 2, the air trapped in the annular recess 24 is compressed by the annular upper protruding portion 23 of the bumper 16. The piston 6 is pushed down to the bottom dead center,
Compress air of 4 strongly. Therefore, the shock caused by the abrupt lowering of the piston 6 not only has a cushioning effect due to the elasticity of the bumper 16, but also the protruding portion 23 of the bumper 16 causes
It is largely absorbed by the cushioning action by the compression of air performed by press-fitting into the recess 24 in a close-fitting manner. This improves the durability of the bumper. Also, by absorbing the shock, the impact sound became quiet and the heat generated by the bumper was kept low. Further, the piston 6 returning from the bottom dead center is urged to move upward by the air compressed in the annular recess 24 to a high pressure, and the returning operation is smoothly performed.

The present invention is also devised to absorb the shock when the piston 6 rapidly returns from the bottom dead center to the top dead center after the impact. Therefore, as shown in FIGS. 1 and 3, the exhaust seal 27 provided above the cylinder 4 is provided with a cushion 28 that annularly projects toward the upper surface of the piston 6. A second annular recess 30 into which the protruding portion 29 of the cushion 28 is fitted is formed on the upper surface of the piston 6. The size of the recess 30 is smaller than the depth of the inlet 31 (lower side of the figure), and the protrusion 29 of the cushion 28 is press-fitted in a tight fit. Therefore, when the piston 6 returns to the top dead center, as shown on the right side of the axis x in FIG. 3, the inlet portion 31 of the second annular recess 30 comes into contact with the protruding portion 29 of the cushion 28, and the air in the recess 30 is there. Lock in. The piston 6 ascends so as to receive the protruding portion 29 of the cushion 28 in the second recess 30 as it is, and as shown on the left side of the axis x in FIG. 3, the air trapped in the second annular recess 30 is projected from the cushion 28. The portion 29 is strongly compressed. As a result, the impact due to the rapid return of the piston 6 has a cushioning function due to the elasticity of the cushion 28, as well as the impact when the piston descends, and the projecting portion 29 of the cushion 28 closes in the second recess 30 of the piston 6. It is largely absorbed by the buffering action due to the compression of air that is carried out by press-fitting in a fitting shape. Therefore, since a hard rubber having a certain degree of strength can be used as the cushion, high durability can be obtained, and the shock absorbing sound at the time of restoration is quiet due to the high cushioning effect, and the heat generation of the cushion is suppressed to a low level.

[0013]

According to the impact tool of the present invention, the impact at the time of impact of the piston is largely absorbed by strongly compressing the air in the recess that causes the bumper protruding portion to be tightly fitted into the recess of the piston. As a result, the durability of the bumper is improved, the impact sound is quieted by absorbing the impact, and the heat generation of the bumper is suppressed to a low level. In addition, the impact due to the rapid return of the piston is also largely absorbed by pressing the protruding portion of the cushion into the second recess of the piston, and the cushion has high durability, and the impact sound at the time of return is quiet, The heat generation is also kept low.

[Brief description of drawings]

FIG. 1 is a cutaway front view of a main part of a fastener hitting tool according to the present invention.

FIG. 2 is a diagram showing a relationship between a piston and a bumper at the time of impact.

FIG. 3 is a diagram showing a relationship between a piston and a cushion at the time of returning.

[Explanation of symbols]

 1 Fixing Tool Hitting Tool 2 Handle 3 Housing 4 Cylinder 5 Hitting Member 6 Piston 7 Main Valve 10 Nose 11 Return Air Chamber 12 Intermediate Hole 13 Lower End Hole 14 Check Valve O-ring 16 Bumper 17 O-ring 18 for Piston Seal 18 Trigger Device 19 Trigger valve pin 20 Tube 21 Main valve chamber 23 Upper protruding portion of bumper 24 Annular recess on lower surface of piston 25 Inlet portion 27 Exhaust seal 28 Cushion 29 Cushion protruding portion 30 Second annular recess of piston 31 Inlet portion

Claims (2)

[Claims] 1. A pressurizing air is supplied to a housing, a cylinder is provided inside the housing, and a piston having a striking member attached therein is reciprocally arranged inside the cylinder. When the air is supplied, the piston rapidly descends and the striking member strikes the fastener with the nose into the object, and when the air above the cylinder is exhausted to the atmosphere, it forms between the cylinder and the housing. Pressurized air in the return air chamber acts on the lower surface of the piston to return the piston to the upper part of the cylinder, and a bumper that absorbs the shock due to the sudden lowering of the piston is provided on the lower end side of the cylinder. In the fastener striking tool having, the upper portion of the bumper projects annularly toward the lower surface of the piston, and the bumper contact surface of the piston has: An annular recess into which the upper projecting portion of the bumper is fitted is formed, and the upper projecting portion of the bumper is closely fitted to the annular recess in a state in which air between the recess and the bumper projecting portion is compressed. Fixing tool striking tool characterized by. 2. The fastener striking tool according to claim 1, wherein a cushion protruding annularly or a protruding portion of the cushion is fitted into the exhaust seal above the cylinder and the upper surface of the piston at positions facing each other.
An annular recess is formed in the cushion
A fastener striking tool, characterized in that air between the second annular recess and the cushion is tightly fitted in the annular recess in a compressed state.