WO2009096395A1

WO2009096395A1 - Nail driver

Info

Publication number: WO2009096395A1
Application number: PCT/JP2009/051285
Authority: WO
Inventors: Toru Uchiyama; Yasunori Aihara
Original assignee: Max Co., Ltd.
Priority date: 2008-01-31
Filing date: 2009-01-27
Publication date: 2009-08-06
Also published as: JP5012538B2; JP2009178811A; TW200948555A

Abstract

A nail driver is provided with an impact cylinder, an impact piston mounted in the impact cylinder so as to be slidable in the vertical direction, a movable sleeve mounted in the upper part of the impact cylinder and vertically moving to open and close a combustion chamber, and a contact member moving upward when pressed against a material to be driven and moving the movable sleeve upward to tightly close the combustion chamber. The contact member is constantly spring-urged in the nail driving direction independent of the movable sleeve.

Description

Nailer

The present invention relates to a nailing machine that holds a member that guides a nail so as not to be separated from a material to be driven when the nail is lifted by reaction.

Generally, in a gas combustion type nailing machine, a striking piston is provided in a striking cylinder disposed in a body so as to be slidable in the vertical direction. The combustion chamber can be opened and closed by moving a movable sleeve provided at the upper part of the striking cylinder up and down to contact and separate the striking cylinder and the cylinder head above it. A mixed gas obtained by stirring and mixing flammable gas and air with a fan in a sealed combustion chamber is ignited by an ignition plug disposed in the cylinder head and burned explosively. The high-pressure combustion gas acts on the striking piston, and the striking piston is driven impactively. A driver coupled to the lower surface side of the striking piston strikes a nail from the nose portion (see Patent Document 1).

Incidentally, a contact member is slidably provided outside the nose portion. The lower end of the contact member is spring-biased so as to protrude from the nose portion. An upper end of the contact member is disposed so as to be engageable with a member called a cage connected to the lower side of the movable sleeve. The cage is always biased downward by a spring.

As a contact member, in addition to a contact arm arranged outside the nose portion as shown in Patent Document 1, a nail driving direction (vertical direction) is provided below the nose portion with the same injection port as the nose portion. There is known a member (so-called contact nose) that is slidably provided (see Patent Document 2). The upper part of the contact nose is also arranged at the lower part of the cage.

In the above configuration, when the nail is driven, when the lower end of the contact member is pressed against the material to be driven, the contact member moves relative to the body. As a result, the upper end of the contact member engages with the cage to move the movable sleeve together with the cage, thereby forming a sealed combustion chamber. Accordingly, combustible gas is ejected into the combustion chamber. When the mixed gas obtained by mixing with air by the fan is ignited by the spark plug, the mixed gas burns. The nail is driven by this combustion pressure.
JP-A-2005-22069 JP2007-30091

However, when the nail is driven, the striking piston is suddenly driven downward, so that the nail driver itself is lifted by the reaction, and the nose portion and the contact member are instantaneously separated from the driven material. Since these members guide the nail to be driven so as to be driven correctly, for example, when the nose portion is separated from the driven material, the nail posture is not maintained. As a result, problems such as buckling are likely to occur, the connecting band is scattered around, the nail is damaged, and the damaged nail is scattered.

The reason is that the contact member is spring-biased together with the movable sleeve, but when the nail driver is lifted by reaction when nailing, the contact member is also separated from the material to be driven. Normally, a coil spring is placed at the top of the cage to urge the movable sleeve and contact nose downward, but when the contact member is pressed against the workpiece, the cage deflects the spring against the coil spring. The movable sleeve is moved to the top dead center, and the movable sleeve is held at the top dead center until the trigger is operated and then released. For this reason, the spring force of the spring does not reach the contact member under the cage. When the nail is driven, the striking piston is suddenly driven downward, so that when the nail driver itself is lifted by the reaction and momentarily separated from the material to be driven, the load that pushes the contact member in the free state downward is Only its own weight. This weight alone is not sufficient to separate the contact member from the driven material. In particular, when nails are driven toward a wall or a ceiling, gravity does not work on the contact member or gravity works in the opposite direction, so that it is not possible to cope with the separation operation.

One or more embodiments of the present invention prevent buckling by preventing the end of the driven portion from separating from the driven material even when a member that guides the nail is subjected to reaction during driving the nail. Provided is a nailing machine capable of satisfactorily preventing scattering of a coupling band of a coupling nail and a broken nail.

According to one or more embodiments of the present invention, a nailing machine includes a striking cylinder, a striking piston slidably disposed in the striking cylinder, and an upper portion of the striking cylinder. A movable sleeve that opens and closes the combustion chamber by moving, and the combustion gas generated by burning the mixed gas in the sealed combustion chamber that is coupled to the lower surface side of the striking piston acts on the striking piston. And a contact member that moves upward by being pressed against the material to be driven and moves the movable sleeve upward to seal the combustion chamber. The contact member is always spring-biased in the nail driving direction independently of the movable sleeve.

In this specification, “downward” means the direction in which the driver drives the nail, and “upward” means the opposite direction of “downward”. That is, when driving a nail into the floor, “downward” substantially corresponds to downward in the direction of gravity. On the other hand, in the case of driving a nail into the ceiling, “downward” substantially corresponds to upward in the direction of gravity. Furthermore, in the case of driving the nail into the vertical wall, “downward” substantially corresponds to the direction perpendicular to the direction of gravity.

The nailing machine may further include a main spring that biases the movable sleeve downward, and a secondary spring that biases the contact member downward.

The nailing machine further includes a lock bar that holds the movable sleeve at the top dead center when the movable sleeve moves to the top dead center, and a gauge provided on the movable sleeve. May be. In the nailing machine, the main spring biases the gauge downward, and when the contact member is moved to the top dead center, the gauge moves upward, and the movable sleeve moves to the top dead center. The contact member can be separated from the gauge, and the contact member can be moved in the direction of the bottom dead center by the secondary spring even when the lock bar holds the movable sleeve at the top dead center. is there.

The contact member may be a contact nose having a nail injection port that is slidably disposed below the nose portion.

The contact member may be a contact arm that is slidable along the nose portion.

The nailing machine may further include a movable cover arranged to cover the outside of the contact member and slidable in the nail driving direction, and the movable cover is spring-biased downward. May be.

The contact member may also be indirectly spring-biased by engaging the movable cover with the contact member and spring-biasing the movable cover downward.

According to one or more embodiments of the present invention, the nail driver is disposed so as to be slidable along the nose portion, a striking mechanism for driving the nail using air pressure as a power source, a nose portion for injecting the nail, A contact member that enables the nail to be driven by being pressed against the workpiece, and a movable cover that is slidable in the nail driving direction and covers the outside of the contact member. The movable cover is always spring-biased in the nail driving direction.

Further, the nailing machine further includes a spring provided between the movable cover and the nose portion, and the movable cover is always spring-biased in the nail driving direction with respect to the nose portion. May be.

The contact member may be a contact nose that is slidably disposed below the nose portion and has a nail injection port.

The contact member may include a contact arm that is slidable along the nose portion.

A contact member that moves upward above the body by being pressed against the material to be driven to move the movable sleeve upward to form a sealed combustion chamber, and a nail driving direction that is arranged to cover the outside of the contact member When the contact member is always spring-biased in the nail driving direction independently of the movable sleeve, the striking piston is suddenly driven downward when the nail is driven. When the nail driver itself is lifted and moved so as to be momentarily separated from the driven material, the contact member protrudes in the driving direction by a spring bias acting independently of the movable sleeve. Is held in contact with the workpiece without leaving the workpiece. Therefore, the position of the nail is maintained, and problems such as buckling, scattering of the connection band, damage to the nail, and scattering of the nail that has been broken do not occur.

In a nailing machine driven by air pressure, a contact nose that allows the nail to be driven by being pressed against the material to be driven is slidable along the nose portion, and the outside of the contact member is arranged in the nail driving direction. When the movable cover is covered with a slidable movable cover and the movable cover is always urged by a spring in the nail driving direction, the nail driver itself is lifted by the reaction during nail driving so that it is separated from the material to be driven instantaneously. Even when the movable cover moves, the movable cover protrudes in the driving direction by the spring force of the coil spring, so that the lower end of the movable cover is held in contact with the workpiece without separating from the driven material. Therefore, even if the contact nose is separated, the nail posture does not tilt greatly, it is difficult to buckle, the connection band is scattered around, the nail is damaged, the damaged nail is scattered, etc. The problem never occurs.

When the contact member is a contact nose having a nail injection port that is slidably disposed below the nose portion, the nail can be directly guided.

When the contact member is a contact arm slidably provided along the nose portion, it is possible to effectively prevent the connection band and the nail from being scattered outside the nose.

When the movable cover is always spring-biased in the nail driving direction, the movable cover will be spring-biased even if the nail driver itself is lifted by the reaction of nail driving and moves away from the driven material instantaneously. Projecting in the driving direction, the lower end of the movable cover is held in a contacted state without separating from the driven material. Therefore, even if the contact nose is separated, the nail posture does not tilt greatly, it is difficult to buckle, the connection band is scattered around, the nail is damaged, the damaged nail is scattered, etc. The problem never occurs.

Also, since the movable cover is always urged by the spring in the nail driving direction, the movable cover is free of rattling, the operation feeling is good, and the contact member is always covered to make it difficult to launch in the air.

Furthermore, when the nail driver is lifted by reaction during nailing, especially when the combustion chamber is held at the top dead center position and the spring force pushing the combustion chamber does not act on the contact member, the movable cover is moved by the spring bias. Since the nail guide is pushed in the nail driving direction, the contact member also produces the same effect.

Other features and effects will be apparent from the description of the embodiments and the appended claims.

1 is a perspective view of a gas fired nail driver according to a first exemplary embodiment of the present invention. Longitudinal sectional view of the main part of the nailing machine in the normal state Longitudinal cross-sectional view of the main part of the nailing machine when nailing Longitudinal sectional view of the nose part of the nailing machine Longitudinal sectional view of the nose of the nailing machine cut along another surface Longitudinal sectional view when the contact nose of the nose part is adjusted to the most floating state Sectional view cut along a plane different from that of FIG. Sectional view of the main part showing the state pressed against the workpiece Vertical section showing the top and bottom dead center of the movable cover Sectional drawing of the principal part which shows the state which biased the movable cover The perspective view of the principal part which shows the state which spring-biased the movable cover The longitudinal cross-sectional view of the principal part which shows the state which urged | biased the movable cover of a pneumatic nailing machine concerning 2nd typical embodiment of this invention. Longitudinal sectional view showing the state pressed against the workpiece Longitudinal sectional view showing a condition that is difficult to launch in the air

Explanation of symbols

1, 1 'body 4, 4' nose part 8 movable sleeve 16, 16 '

contact nose

43, 53, 53' coil spring 38, 38 'movable cover

Hereinafter, typical embodiments of the present invention and modifications thereof will be described based on the drawings.

<First Exemplary Embodiment>
1 and 2, reference numeral 1 indicates a body of a combustion nailing machine. A striking mechanism is provided inside the body 1, and an injection nose for striking a nail is provided below. A gas can (not shown) filled with a fuel gas liquefied from a combustible gas is attached to the rear of the striking mechanism. A grip 2 and a magazine 3 are connected to the body 1, and the magazine 3 is configured to open to the nose portion 4 and supply nails.

The striking mechanism is a combustion in which a striking piston 6 is slidably provided in a striking cylinder 5 disposed in the body 1 and hermetically formed as shown in FIG. 3 by a movable sleeve 8 provided on the top of the striking cylinder 5. In the chamber 10, the combustible mixed gas is ignited and explosively burned, and the striking piston 6 is driven by the high-pressure combustion gas to strike the nail in the nose portion 4. 9 is a trigger for starting operation.

That is, the striking piston 6 is slidably accommodated in the striking cylinder 5, and the striking piston 7 is integrally coupled below the striking piston 6. Further, the upper wall portion 11 of the nose portion 4 is formed in a dish shape, and an injection port 12 for guiding the sliding of the striking piston 7 is formed at the center thereof. The rear side of the injection port 12 opens at the tip of the magazine 3.

The combustion chamber 10 is formed by an annular movable sleeve 8 disposed between the upper end surface of the impact piston 6 and a cylinder head 13 formed inside the impact cylinder 5 and the upper portion of the body 1. A sealed combustion chamber 10 is formed by moving the sleeve 8 upward to seal the cylinder head 13 as shown in FIG. 3, and an upper portion of the combustion chamber 10 by moving downward as shown in FIG. Is open and communicates with the atmosphere.

The lower end of the movable sleeve 8 is connected to the upper end of the contact member 14. The contact member 14 is provided so as to be slidable in the nail driving direction along the nose portion 4 and moves upward relative to the nose portion 4 by pressing the lower end against the driven material P. ing. The contact member 14 will be described in detail later.

Incidentally, as shown in FIGS. 3 and 4, the movable sleeve 8 is operatively linked to the contact member 14 through a member called a cage 17. The cage 17 is formed by connecting the lower ends of the link-like portions 17a on both sides with the bottom portion 17b. Although the link-like portions on both sides are omitted in the drawing, the upper end is coupled to the lower end of the movable sleeve 8, and the bottom portion 17b is the nose. It is arranged between the part 4 and the striking cylinder 5. A main coil spring (main spring) 18 is disposed between the lower surface of the striking cylinder 5 and the bottom portion 17b of the cage 17, whereby the movable sleeve 8 is constantly urged downward. A contact member 14 is engaged with the lower portion of the cage 17.

It should be noted that since it is a known technique, the description is omitted, but the operation of the trigger 9 is made effective only when the contact member 14 moves to the top dead center together with the movable sleeve 8. Further, when the movable sleeve 8 moves to the top dead center, the lock bar 20 is held at that position.

The cylinder head 13 is injected into the combustion chamber 10 by the injection nozzle 21 communicating with the gas container, an ignition plug (not shown) for igniting and burning the mixed gas, and the injection nozzle 21. A rotating fan 22 is provided for agitating the combustible gas with the air in the combustion chamber 10 to generate a mixed gas having a predetermined air-fuel ratio in the combustion chamber 10. Reference numeral 23 denotes a gas can storage chamber.

When starting the nailing machine, first, as shown in FIG. 3, the lower end of the contact member 14 is strongly pressed against the workpiece P, and the contact member 14 is moved to the top dead center. As a result, the movable sleeve 8 is also moved upward together with the cage 17 to come into contact with the cylinder head 13 to form a sealed combustion chamber 10. When the combustion chamber 10 is sealed, the combustible gas is injected from the injection nozzle 21 into the combustion chamber 10, the motor is operated, the rotary fan 22 rotates, and the combustible gas and air are agitated and mixed.

Since the operation of the trigger 9 becomes effective when the contact member 14 moves to the top dead center, when the trigger 9 is pulled, the circuit connected to the spark plug is turned on, so that the mixed gas is ignited and burned. And expands explosively. The pressure of the combustion gas acts on the upper surface of the striking piston 6 to drive downward, and the driver 7 strikes a leading nail (not shown) in the magazine 3 supplied in the nose portion 4; Drive into the workpiece P.

When the driving is completed, the temperature in the combustion chamber 10 suddenly decreases, so that the space above the striking piston 6 that has expanded to the striking cylinder 5 becomes negative pressure, and the striking piston 6 is top dead due to the differential pressure from the atmospheric pressure from below. Move return to point. Then, by pulling up the nail driver to separate the nose portion 4 from the driven material P, the urging force of the main coil spring 18 causes the movable sleeve 8 and the contact member 14 to move downward to open the combustion chamber 10, and FIG. Thus, the next driving operation is prepared by returning to the initial state.

Incidentally, as shown in FIG. 4, the contact member 14 includes an upper arm member 15 and a lower contact nose 16. The arm member 15 is an arm-like member whose upper and lower ends are bent, and the upper portion penetrates the upper wall portion 11 of the nose portion 4, and the upper end bent portion 15 a is disposed so as to be engageable with the bottom portion 17 b of the cage 17, The movable sleeve 8 is linked via the cage 17. An injection port 12 is formed below the contact nose 16 so as to be continuous with the injection port of the nose portion 4. A bulging portion 24 that extends outward is formed at the upper end of the injection port 12, and an upper cylindrical portion 25 of the bulging portion 24 is formed in a large-diameter cylindrical shape so as to surround the nose portion 4. ing.

The lower end of the arm member 15 and the upper end of the contact nose 16 are connected through an adjustment mechanism a. The adjustment mechanism a adjusts the contact nose 16 to move in the nail driving direction. As shown in FIGS. 5 and 10, the adjustment mechanism a moves laterally from the upper wall portion 11 of the nose portion 4 and the midway portion of the nose portion 4. A hollow screw 27 provided between the projecting support arm 26 and a first screw shaft 28 which is inserted into the hollow screw 27 so as to be movable up and down and rotates integrally with the hollow screw 27. The adjustment screw 30, the arm member 15 held at the same position of the screw shaft 28, and the contact nose 16 screwed into the first adjustment screw 30 are configured.

A bent portion 31 is formed at the lower end of the arm member 15, and the bent portion 31 is held so as to be rotatable with respect to the screw shaft 28 and not movable up and down. On the other hand, a connecting piece 33 is formed so as to protrude from one side of the upper cylindrical portion 25 of the contact nose 16, and a female screw portion 34 formed on the connecting piece 33 is screwed to the first adjusting screw 30. .

According to the adjusting mechanism a, when the adjusting dial 35 fixed to the upper end of the hollow screw 27 is rotated, the first adjusting screw 30 is rotated together with the screw shaft 28 as shown in FIG. When the first adjustment screw 30 rotates, the lower end bent portion 31 of the arm member 15 is held at the same position, but the first adjustment screw 30 and the connecting piece 33 at the upper end of the contact nose 16 are screwed together. Therefore, the contact nose 16 slides in the nail driving direction. As a result, the entire length of the contact member 14 changes and the top dead center position does not change, but the lower end position of the contact nose 16 at the bottom dead center changes, so that the nail driving depth can be adjusted.

Incidentally, when the nail is driven so as to be most depressed with respect to the workpiece (hereinafter referred to as the most depressed state), the adjustment may be performed as shown in FIG. In this case, since the lower end of the contact nose 16 approaches the bottom dead center of the striking piston 7, when the contact nose 16 is pressed against the workpiece and the nail is driven out, the nail is driven deeply by the striking piston 7. The part sinks into the surface of the workpiece. On the other hand, when the nail is driven so as to be in the most floating state (hereinafter referred to as the most floating state) with respect to the driven material, adjustment may be performed as shown in FIG. In this case, since the tip of the contact nose 16 is far from the bottom dead center of the striking piston 7, when the contact nose 16 is pressed against the workpiece and the nail is driven out, the nail is driven shallowly by the striking piston 7. The part floats from the surface of the workpiece. Therefore, optimum driving can be realized according to the material of the material P to be driven.

The top dead center position of the contact member 14 is a position when the lower end bent portion 31 of the arm member 15 contacts the lower surface of the support arm 26 of the nose portion 4. At this time, the above-described movable sleeve 8 moves upward. A closed combustion chamber 10 is formed. Moreover, the bottom dead center position is a position when the upper end bending part 15a contacts the upper protrusion 36 (refer FIG. 4) of the upper wall part 11 of the nose part 4 in principle. The top dead center and the bottom dead center of the contact nose 16 are moved by adjustment by the adjustment mechanism a.

Next, the nose portion 4 and the contact member 14 are covered with a cover. As shown in FIG. 4, the cover includes a fixed cover 37 and a movable cover 38. As shown in FIG. 1, the fixed cover 37 covers the front part of the nose part 4, the adjustment mechanism a, and the lower part of the arm member 15. The cover and the movable cover 38 are formed so as to cover the outer periphery of the contact nose 16.

The distal end side (lower part) of the movable cover 38 is formed in a straight cylindrical shape, and the mortar-shaped part 41 at the upper part of the cylindrical part 40 is formed so as to gradually spread in a mortar shape and become thicker. Similarly, the upper portion of the contact nose 16 is also formed in a large-diameter cylindrical shape via the bulging portion 24, and the lower surface of the bulging portion 24 has a shape that matches the upper surface of the mortar-shaped portion 41. Therefore, the bulging portion 24 of the contact nose 16 can be in contact with the mortar-shaped portion of the movable cover 38, and the contact member 14 is restricted to a position in contact with the movable cover 38 and cannot move further downward.

Next, as shown in FIG. 7, the spring receiver 16 a at the upper end of the contact nose 16 is formed with a spring receiver 42, and between the spring receiver 42 and the upper wall 4 a of the nose 4. A coil spring 43 is arranged. The contact nose 16 is always urged by the spring force of the coil spring (secondary spring) 43 so as to protrude in the nail driving direction.

According to the above configuration, the movable sleeve 8 and the contact nose 16 are urged downward by the main coil spring 18 and the coil spring 43 arranged on the bottom portion 17b of the cage 17. When the nail is driven, when the contact nose portion 16 is pressed against the driven material P as shown in FIG. 8, the cage 17 deflects the spring against the main coil spring 18 as described above, and the movable sleeve 8 is set to the top dead center. Since the movable sleeve 8 is held at the top dead center until it is moved and released after the trigger 9 is operated, the spring force of the main coil spring 18 does not reach the contact nose 16 below the cage 17. However, the coil spring 43 urges the contact nose 16 to move downward. Therefore, when the nail driving piston 6 is suddenly driven downward when the nail is driven, the nail driver itself is lifted by the reaction and moved so as to be instantaneously separated from the driven material, as shown in FIG. Since the nose 16 protrudes in the driving direction due to the spring force of the coil spring 43, the lower end of the contact nose 16 is held in a contacted state without separating from the driven material P. Therefore, the position of the nail is maintained, and problems such as buckling, scattering of the connection band, damage to the nail, and scattering of the nail that has been broken do not occur.

Note that the spring force of the coil spring 43 may be small as long as it is sufficient to urge the contact nose 16 to move downward.

Further, the main coil spring 18 that urges the cage 17 upward does not need to be disposed in the nose portion 4. The structure arrange | positioned at the upper part of the movable sleeve 8 or the side part of the striking cylinder 5 may be sufficient.

7 and 8, the contact nose 16 is cut at the side wall, so that it does not appear hollow, but of course the main part is formed hollow.

<First Modification of First Exemplary Embodiment>
By the way, prevention of separation from the driven material of the nailing machine is not limited to the configuration in which the contact member is spring-biased. As shown in FIGS. 9 to 11, the cover member may be configured to be spring-biased.

That is, as shown in FIG. 9, the periphery of the nose portion 4 is covered with the fixed cover 37, and the periphery of the contact nose 16 is covered with the movable cover 38, and the contact nose 16 is directly pushed up by hand to be in the air. Cannot fire. The movable cover 38 is slidable along the contact nose 16 in the nail driving direction. The bottom dead center of the movable cover 38 is movable at a position where the lower end of the movable cover 38 is substantially the same as the lower end of the contact nose 16 so that the adjustment mechanism a is aligned with the bottom dead center when the contact nose 16 is in the most depressed state. This is a position where the engaging portion 45 formed at the upper end of the arm portion 44 protruding above the cover 38 is in contact with the protrusion 46 provided on the nose portion 4.

Also, as shown in FIG. 4, the position where the upper engaging piece 52 of the movable cover 38 abuts on the rising portion 54 (locking portion) on the upper portion of the contact nose 16 may be set as the bottom dead center position.

Further, the top dead center position of the movable cover 38 is a position where it comes into contact with the adjustment nut 48 that moves up and down in conjunction with the contact nose 16 when the adjustment mechanism a is operated. That is, a second adjustment screw 47 is formed on the outer periphery of the hollow screw 27, and an adjustment nut 48 is screwed to the second adjustment screw 47. The adjustment nut 48 is engaged with the nose portion 4 so as not to rotate, and an L-shaped engagement piece 50 is integrally formed on a side portion of the adjustment nut 48, and the lower end of the engagement piece 50 is formed on the movable cover. 38 is formed so as to face the arm portion 44 protruding upward from the upper end of 38, and the engagement piece 50 and the arm portion 44 come into contact with each other.

According to the above configuration, when the adjustment dial 35 of the adjustment mechanism a is rotated, the second adjustment screw 47 is rotated and the adjustment nut 48 is moved in parallel with the nail driving direction. However, when the second adjustment screw 47 rotates, the first adjustment screw also rotates as described above, so that the contact nose 16 also moves in the same direction. Accordingly, by rotating the adjustment dial 52, the adjustment nut 48 and the contact nose 16 are interlocked, and the support arm 53 of the contact nose 16 and the adjustment nut 48 always maintain the same positional relationship. As described above, the top dead center of the movable cover 38 also changes in the nail driving direction in accordance with the position of the adjustment nut 48 interlocked with the contact nose 16, but no matter where the adjustment nut 48 is located, the top dead center The protruding amount of the contact nose 16 protruding from the lower end of the movable cover 38 is always substantially the same, and the protruding amount is small.

Therefore, if the movable cover 38 is pushed up to the top dead center and the contact nose 16 is pushed up to the top dead center, the nail driver can theoretically be activated in the air, but the protruding amount of the contact nose 16 is small. Even if you use a tool, it is very difficult to push it to top dead center, and it is practically impossible to fire a nail in the air.

As shown in FIGS. 10 and 11, a spring receiving portion 42 is formed at the upper end of the movable cover 38, and a coil spring 53 is provided between the spring receiving portion 42 and the upper wall portion 4 a of the nose portion 4. Is arranged. The movable cover 38 is always urged by the spring force of the coil spring 53 so as to protrude in the nail driving direction.

Therefore, even with the above configuration, even if the striking piston 6 is suddenly driven downward at the time of nail driving and the nail driver itself is lifted by the reaction and moves so as to be momentarily separated from the material to be driven, the movable cover Since 38 protrudes in the driving direction by the spring force of the coil spring 53, the lower end of the movable cover 38 is held in a contacted state without separating from the driven material. Therefore, even if the contact nose 16 is separated, the nail posture does not tilt greatly, buckling is unlikely to occur, the connection band is scattered around, the nail is damaged, or the damaged nail is scattered. Such a problem does not occur.

Further, since the movable cover 38 is always urged by the spring in the nail driving direction, there is no backlash, the operation feeling is good, and the contact nose 16 is always covered, so that the air launch can be made more difficult.

<Second Modification of First Typical Embodiment>
Note that a configuration in which both the contact nose 16 and the movable cover 38 are not spring-biased but only one of them is spring-biased may be employed. For example, if only the movable cover 38 is spring-biased, the main coil spring 18 that pushes the movable sleeve 8 while the combustion chamber is held at the top dead center position, particularly when the nail driver is lifted by reaction during nail driving. The spring force does not act on the contact nose 16, but not only the movable cover 38 but also the rising portion 54 at the top of the contact nose 16 is engaged by the engagement piece 52 of the movable cover 38 as shown in FIG. Since the contact nose 16 is also pushed in the nail driving direction through the movable cover 38 by adopting the matching configuration, the contact nose 16 can also produce the same nail guide effect.

<Second exemplary embodiment>
Next, a structure for preventing separation from a material to be driven in a pneumatic nail driver for driving a nail using compressed air as a drive source will be described with reference to FIGS.

The nail driver shown in FIG. 12 includes a body 1 ′ having a striking mechanism for driving out a nail using air pressure as a driving source, and a nose portion 4 ′ provided below the body 1 ′ and ejecting the nail. A contact nose 16 ′ having a nail injection port below 4 ′ is slidably provided. Also in this example, the contact nose 16 ′ is integrally coupled with the upper arm member 15 ′, and the contact nose The spring is biased so that the lower end of 16 'protrudes toward the lower end. The upper end of the arm member 15 'is disposed so as to be engageable with the contact lever 55 of the trigger 9'.

When driving a nail by the nailing machine, the contact nose 16 'is pressed against the material to be driven and pressed into the body 1', thereby pushing up the arm member 15 'against the spring bias and contacting the trigger 9'. The lever 55 is rotated. By pulling up the trigger 9 'in this state, the valve stem 57 of the start valve 56 is pushed in and the nail driver is started. Even if the trigger 9 ′ is pulled without pressing the contact nose 16 ′, the contact lever 55 cannot press the valve stem 57, so it does not start.

The contact nose 16 'is covered with a movable cover 38'. The movable cover 38 'has a cylindrical shape, and an engagement piece 58 is bent at a part of the upper end. The engagement piece 58 can engage with the upper end of the contact nose 16' and the lower surface 61 of the nose portion 4 '. Yes. A coil spring 53 'is provided between the bent portion 59 at the upper end of the movable cover 38' and the protruding portion 60 of the nose portion 4 '. The movable cover 38' is always urged downward by the coil spring 53 '. . Therefore, the engagement piece 58 of the movable cover 38 'is always engaged with the upper end of the contact nose 16'. As shown in FIG. 13, when the contact nose 16 ′ is pressed against the workpiece P and moves to the top dead center, the movable cover 38 ′ also moves upward and engages the lower surface of the nose portion 4 ′.

Therefore, even with the above configuration, even if the striking piston 6 is suddenly driven downward at the time of nail driving and the nail driver itself is lifted by the reaction and moves so as to be momentarily separated from the material to be driven, the movable cover Since 38 'protrudes in the driving direction by the spring force of the coil spring 53', the lower end of the movable cover 38 'is held in a contacted state without separating from the driven material. Therefore, even if the contact nose 16 'is separated, the movable cover 38' does not tilt the nail so that buckling is unlikely to occur, and the connection band is scattered around, the nail is damaged, Problems such as spatter of damaged nails do not occur.

According to the above configuration, when the movable cover 38 ′ moves in the nail driving direction by the spring force of the coil spring 53 ′, the engagement piece 58 of the movable cover 38 ′ is always engaged with the upper end of the contact nose 16 ′. Therefore, the contact nose 16 ′ also moves in the nail driving direction, so that the above-described effects can be exhibited.

Also, since the movable cover 38 'is always urged by the spring in the nail driving direction, there is no backlash, the operation feeling is good, and it is possible to make air launch more difficult by always covering the contact nose 16'.

As shown in FIG. 14, even if the movable cover 38 ′ is lifted up to the top dead center by hand and the tip of the exposed contact nose 16 ′ is pushed in the air to drive out the nail, the movable cover 38 ′ is a coil spring. Since it is biased downward by 53 ′, it is difficult to hold at the top dead center, and the exposure amount of the contact nose 16 ′ is very small. Because it is difficult, it is practically impossible to fire a nailer in the air.

Furthermore, although the above-mentioned embodiment is an example which provided the movable cover in the contact nose, the structure which provides a movable cover in the arm member of the nail driver using compressed air, and urges the movable cover or the contact arm downward. The same effect can be obtained also.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

This application is based on a Japanese patent application filed on January 31, 2008 (Japanese Patent Application No. 2008-020302), the contents of which are incorporated herein by reference.

The present invention can be used for a nailing machine driven by using a gas combustion pressure or air pressure as a driving source.

Claims

A striking cylinder;
A striking piston arranged slidably in the up-down direction in the striking cylinder;
A movable sleeve that is disposed at the top of the impact cylinder and opens and closes the combustion chamber by moving up and down;
A driver coupled to the lower surface side of the striking piston and driving a nail in the nose portion downward when combustion gas generated by burning the gas mixture in the sealed combustion chamber acts on the striking piston;
A contact member that moves upward by being pressed against the workpiece and moves the movable sleeve upward to seal the combustion chamber;
Comprising
The nailing machine, wherein the contact member is always spring-biased in the nail driving direction independently of the movable sleeve.
Furthermore,
A main spring that biases the movable sleeve downward;
A secondary spring for urging the contact member downward;
The nail driver according to claim 1, comprising:
Furthermore,
A lock bar that holds the movable sleeve at the top dead center when the movable sleeve moves to the top dead center;
A gauge provided on the movable sleeve;
Comprising
The main spring biases the gauge downward,
When the contact member is moved to the top dead center, the gauge moves upward, the movable sleeve moves to the top dead center,
The contact member and the gauge can be separated from each other, and the contact member can be moved in the direction of the bottom dead center by the secondary spring even when the lock bar holds the movable sleeve at the top dead center. is there,
The nail driver according to claim 2.
The contact member is composed of a contact nose having a nail injection port that is slidably disposed below the nose portion.
The nailer according to claim 1.
The contact member is composed of a contact arm slidably provided along the nose portion.
The nailer according to claim 1.
And a movable cover arranged to cover the outside of the contact member and slidable in the nail driving direction,
The movable cover is spring-biased downward,
The nailer according to claim 1.
The movable cover is engaged with the contact member,
When the movable cover is spring-biased downward, the contact member is also indirectly spring-biased.
The nail driver according to claim 6.
A striking mechanism for driving nails using air pressure as a power source;
A nose portion for injecting nails;
A contact member that is slidably disposed along the nose portion, and that allows the nail to be driven out by being pressed against the workpiece;
A movable cover that is slidable in the nail driving direction and covers the outside of the contact member;
Comprising
The movable cover is always spring-biased in the nail driving direction,
Nailer.
Furthermore,
A spring provided between the movable cover and the nose portion;
The movable cover is always spring-biased in the nail driving direction with respect to the nose portion.
The nail driver according to claim 8.
9. The nailing machine according to claim 8, wherein the contact member is formed of a contact nose having a nail injection port that is slidably disposed below the nose portion.
The nailing machine according to claim 8, wherein the contact member comprises a contact arm slidably provided along the nose portion.