JPH0666971U - Fixing tool striking tool - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a fastener striking tool that prevents the "peeling" phenomenon from appearing in a bumper even if a bumper having a sufficient shock absorbing force is used. [Structure] In a fastener striking tool 1, pressurized air is supplied to a housing 3, a cylinder 4 is provided inside the housing, and a piston 6 to which a striking member 5 is attached is reciprocally movable inside the cylinder. When the pressurized air is supplied from the upper part of the cylinder, the piston rapidly descends and the striking member drives the fastener with the nose 10 into the object, and then the air on the upper part of the cylinder is exhausted to the atmosphere. When done,
Pressurized air in the return air chamber 11 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, and absorbs the impact due to the sudden lowering of the piston. A bumper 16 is provided on the lower end side of the cylinder. Piston 6
An annular recess 26 that restricts the deformation of the upper surface side portion of the bumper is formed on the surface of the side that contacts the bumper 16.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastener hitting tool such as a nail driving machine, and more particularly to a mechanism for protecting a bumper that absorbs an impact caused by a rapid lowering of a piston.

[0002]

[Prior art]

 Pressurized air is supplied to the housing, a cylinder is provided inside the housing, and a piston equipped with a striking member is reciprocally arranged inside the cylinder, and pressurized air is supplied from the upper part of the cylinder. Then, the piston rapidly descends and hits the fastener with the striking member at the nose to the object, and when the air above the cylinder is exhausted to the atmosphere, the pressurized air in the return air chamber of the piston A fastener hitting tool is well known in which the piston is designed to return to the upper part of the cylinder by being applied to the lower surface, and a bumper that absorbs the shock due to the sudden lowering of the piston is provided on the lower surface of the cylinder. And is often used at construction sites.

[0003]

[Problems to be solved by the device]

 In a conventional fastener impact tool, if a bumper with a high strength and hardness is used, the durability will increase, but the shock absorption will be low, and the shock will be transmitted to the entire tool, and the shock will be transmitted to the hands of workers, etc. Moreover, the parts of the tool may be damaged. On the other hand, if a soft bumper is used, shock absorption is improved, but in the case of a bumper made of a soft material such as rubber, the deformation stress of the bumper concentrates on the outer peripheral part of the upper surface of the bumper, and gradually the outer peripheral part is entirely covered. There was a phenomenon in which the bumper cracked from the part that was “peeled” over the end.

Therefore, an object of the present invention is to provide a fastener striking tool that prevents the "peeling" phenomenon from appearing in the bumper even if a bumper having a sufficient shock absorbing force is used.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, according to the present invention, pressurized air is supplied to the housing, a cylinder is provided inside the housing, and a piston having a striking member mounted therein is reciprocally movable. When the pressurized air is supplied from the upper part of the cylinder, the piston rapidly descends and hits the fastener with the striking member at the nose to the object, then the air on the upper part of the cylinder is exhausted to the atmosphere. Then, the pressurized air in the return air chamber formed between the cylinder and the housing acts on the lower surface of the piston so that the piston returns to the upper part of the cylinder. A fastener striking tool in which a bumper to be absorbed is provided on the lower end side of the cylinder, and the surface of the piston that is in contact with the bumper is the bumper. Fastener impact tool characterized by Rukoto recess annular upper surface portion is restricted from being deformed are formed is provided.

[0006]

【Example】

 An embodiment of a fastener striking tool according to the present invention will be described below with reference to the drawings. 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 this main valve seals the upper end of the cylinder 4 and does not supply the pressurized air in the housing 3 into the cylinder (a position shown in the figure). The seal at the upper end of the cylinder 4 is released, and a striking position (not shown) for supplying pressurized air from the housing 3 is taken. The striking position of the main valve 7 is the position where the main valve 7 is lifted in the direction of the arrow 8, and at this striking position, as shown by the arrow 9, pressure is applied from the gap between the main valve 7 and the upper end of the cylinder 4. Air is supplied to the upper part of the piston 6, and the piston 6 is strongly and rapidly pushed downward.

By this pushing down, the hitting member 5 hits the fixing tool on the nose 10 and hits 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 portion of the cylinder 4 and the housing 3 on the outer periphery of the cylinder. While the descending piston 6 is still in the upper part of the cylinder, the air below the piston 6 is stored in the return air chamber 11 through the intermediate hole 12 of the cylinder 4 and the hole 13 on the lower end side, and the piston 6 keeps the intermediate hole 12 in the middle. When passing, not only the air below the piston is supplied through the hole 13 on the lower end side, but also pressurized air in the cylinder chamber above the piston is newly supplied through the intermediate hole 12. Since the intermediate hole 12 is provided with an O-ring 14 as a check valve, it does not flow backward from the intermediate hole 12 to the cylinder side, and a sufficient amount of pressurized air is stored in the return air chamber 11. Therefore, when the main valve 7 returns to the rest position (the position shown in the figure), the air above the cylinder is exhausted to the atmosphere, and the pressurized air in the return air chamber 11 flows into the cylinder chamber below the piston through the hole 13 on the lower end side. Then, the pressurized air acts on the lower surface of the piston 6 and 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. That is, when the trigger 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. It is in the position shown. 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 pin 19 is pushed upward, the air in the main valve chamber 21 is exhausted to the atmosphere through the trigger device 18, and since the force for pushing down the main valve 7 is lost, the main valve 7 is pushed up and the arrow 8 indicates. As shown by the arrow 9, pressurized air is supplied to the upper part of the piston 6, and the piston 6 is strongly pushed downward so that the striking member 5 drives the nose fastener into the target object. . When the trigger pin 19 is released, it returns to the original position and the main valve 7 returns to the rest position shown. That is, the pressurized air is no longer supplied to the upper surface side of the piston 6 that has been pushed down, and the action of the pressurized air from the return chamber 11 causes the piston 6 to move inside the cylinder 4 from its bottom dead center. To rise.

The piston 6 rapidly descends to the lower end side of the cylinder 4 in order to drive the fastener into the object. The bumper 16 is essential for stopping the piston 6. The bumper 16 is arranged on the lower end side of the cylinder 4, and is formed in a donut shape having a hole through which the striking member 5 passes, and shocks due to a rapid downward movement of the piston 6 are distributed over the entire circumference thereof. Absorb across. If this bumper is made of hard and strong material, its durability will increase, but its shock absorption will be low, and the shock will be transmitted to the entire tool, and it will also be transmitted to the hands of workers, and the parts of the tool It will be damaged. On the other hand, when a soft bumper is used, the shock absorption is improved, but the durability of the bumper is reduced, and the deformation becomes large, and the bumper may be plastically deformed or may be heated and damaged. Therefore, the bumper is made of rubber with a certain hardness that has good shock absorption. In the case of a bumper made of a material such as rubber, the deformation stress of the bumper concentrates on the outer peripheral portion of the bumper upper surface, and gradually the entire outer peripheral portion is "peeled", and finally the bumper cracks from that portion. It was observed.

The above-mentioned “peeling” phenomenon will be described with reference to FIGS. 2A and 2B. 2A shows the state immediately before the lower surface of the piston 6 contacts the bumper 16, and FIG. 2B shows the state where the lower surface of the piston impacts the bumper 16 and crushes the bumper. Is shown. In FIG. 2 (A), the bumper 16 has the original shape, but in FIG. 2 (B), the bumper 16 is crushed by the pressing force of the piston lower surface 23. In this way, the bumper 16, which is in contact with the piston from above, first has a high stress on the upper side, and this stress gradually propagates downward, but at the initial stage of crushing, the bumper upper surface with a low degree of restraint The deformation stress concentrates on the outer peripheral portion 24. Due to this stress concentration, as the tool is used, gradually, a "peeling" phenomenon appears in the portion 24 over its entire circumference, which makes the mouse appear to be a bite. If you continue to use the product with this "peeling", the bumper 16 will eventually break and the shock absorption capacity will be lost.

In the present invention, as shown in FIG. 1, FIG. 3 and FIG. 4, the surface of the piston 6 that contacts the bumper 16, that is, the lower surface of the piston is devised. Specifically, an annular recess 26 that restricts the deformation of the upper surface side portion of the bumper 16 is formed. The depression 26 regulates the deformation of the bumper upper surface side portion in accordance with the depression 26 so that the upper surface side portion of the bumper 16 is less likely to be deformed to some extent. The recess 26 is formed in an annular shape and regulates the upper surface side portion of the bumper 16 over the entire circumference thereof. Therefore, as shown in the state immediately before the deformation in FIG. 3 to the state after the deformation in FIG. 4, the stress that deforms the bumper 16 is quickly dispersed from the upper surface side portion to the lower surface side portion of the bumper, and as shown in FIG. As described above, the deformation stress does not concentrate on the outer peripheral portion 24 on the upper surface of the bumper. Therefore, the "peeling" phenomenon disappears.

[0012]

[Effect of device]

 According to the impact tool of the present invention, the piston has a ring-shaped recess on the surface of the piston that contacts the bumper, which restricts the deformation of the upper surface of the bumper. It is quickly dispersed from the upper surface of the bumper to the lower surface, and the concentration of deformation stress on the outer peripheral surface of the upper surface of the bumper is eliminated, eliminating the "peeling" phenomenon. Therefore, even if a bumper made of rubber or the like is used, the shock absorbing property is maintained for a long time and the durability is high. Also, the bumper itself can be downsized. Moreover, since the annular recess is formed in the piston, the weight of the piston is reduced, which in turn reduces the weight of the entire tool.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a “peeling” phenomenon of a bumper of a conventional tool.

FIG. 3 is an enlarged view of the bumper portion of the tool according to the present invention, showing the state immediately before the piston comes into contact with the bumper.

FIG. 4 is an enlarged view of the bumper portion of the tool according to the present invention, showing a state in which the piston contacts the bumper and deforms the bumper.

[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 pin 20 Tube 21 Main valve chamber 23 Lower surface of piston 24 Outer peripheral portion of upper surface of bumper 26 Annular depression of piston

Claims (1)

[Scope of utility model registration request] 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 air is supplied, the piston rapidly descends and hits the fastener with the striking member at the nose to the object, and when the air above the cylinder is exhausted to the atmosphere, the space between the cylinder and the housing is reduced. Pressurized air in the return air chamber formed on the lower part of the piston acts on the lower surface of the piston so that the piston returns to the upper part of the cylinder. In the provided fastener striking tool, on the surface of the piston that is in contact with the bumper,
A fixing tool striking tool, characterized in that an annular recess is formed to restrict deformation of the upper surface side portion of the bumper.