JP4877470B2 - Contact strike prevention mechanism of gas combustion type driving tool - Google Patents

Description

  The present invention relates to a contact striking prevention mechanism for a gas combustion type driving tool that prevents a so-called contact striking by driving a striking mechanism by first pressing a trigger for starting and then driving a striking mechanism. .

  In general, a gas combustion type nailing machine injects a combustible gas into a combustion chamber sealed in a tool body, agitates a mixed gas of combustible gas and air in the combustion chamber, and mixes the agitated mixed gas into the combustion chamber. The combustion chamber generates a high-pressure combustion gas in the combustion chamber, and this high-pressure combustion gas acts on the striking piston accommodated in the striking cylinder to drive the striking piston in a shocking manner. A nail supplied to a nose portion below the tool body is driven into a steel plate or concrete by a driver coupled to the lower surface side of the striking piston.

  By the way, the combustion chamber has a structure that can be closed and combusted by moving a movable sleeve arranged on the outer side of the striking cylinder so as to be movable up and down, and the movable sleeve is moved up by a contact arm. The contact arm is slidable up and down along the nose part, and its tip protrudes downward from the lower end of the nose part. When driving the nail into the nail, the contact arm is relatively It is configured to move up. The contact arm and the movable sleeve are connected by a link member, and when the contact arm is moved upward, the movable sleeve is also moved upward via the link member, and the upper end of the contact arm comes into contact with the upper wall of the tool body to be in a sealed state. At the same time, a mixed gas is supplied inside.

  Also, by pulling the trigger, the trigger switch is turned on, the spark plug is ignited, and the mixed gas in the combustion chamber is combusted.

  By the way, a lockout bar formed integrally with the link member is disposed beside the cam plate interlocked with the trigger. For this reason, even if the trigger is pulled before the pressing operation of the contact arm, the cam plate cannot hit the lockout bar and cannot rotate, so the trigger cannot be pulled. In other words, it is configured so that the trigger cannot be pulled and activated only after the contact arm is pressed against the workpiece and the sealed combustion chamber is formed.

  As described above, if the trigger is pulled and the cam plate is rotated and kept in contact with the lockout bar, the trigger switch cannot be turned on, but the contact arm is maintained with the trigger pulled. Is pressed against the material to be driven, the lockout bar slides upward along the cam plate together with the link member, moves to a position disengaged from the cam plate, the combustion chamber is sealed, and the trigger is further pulled. Therefore, the trigger switch can be turned on. In this case, it is possible to perform contact driving in a normal nailing machine (by pulling a trigger first and pressing the contact arm against the material to be driven for nail driving).

  In other words, the gas combustion type nailer has a structure that cannot be contacted normally, but there is a problem that the nailing machine is driven if a special method as described above is used.

Therefore, in order to solve the above problem, a technique is known in which contact is not made by electrically controlling the ignition system (see Patent Document 2).
JP 2005-22069 A Japanese Patent Laid-Open No. 7-156076

  However, the electrical control method is very complicated and increases the cost.

  An object of the present invention is to provide a contact firing prevention mechanism for a gas combustion type driving tool capable of eliminating the above-mentioned drawbacks and ensuring safety by reliably preventing contact strike with a simple structure.

In order to solve the above-mentioned problem, the invention according to claim 1 is slidable along a striking cylinder in which a striking piston is slidable in the vertical direction and a nail driving nose portion provided in a lower portion of the tool body. A contact member disposed so that a lower end thereof protrudes from a lower end of the nose portion, and a movable sleeve disposed on the striking cylinder so as to be movable up and down. By interlocking and pressing the contact member against the workpiece, the movable sleeve can be moved upward to form a sealed combustion chamber, and the start trigger is operated to explode the mixed gas in the combustion chamber. Thus, the impact piston is shocked to drive out the fastener supplied to the nose portion, and provided integrally with the lower portion of the movable sleeve. The lockout bar lateral position of the cam plate that rotates in conjunction with the start-up trigger and placement, when the movable sleeve is operated pull the trigger after the upward movement, in conjunction with the trigger In the gas combustion type driving tool in which the rotated cam plate is moved below the lockout bar and held so that the movable sleeve does not move downward, the cam plate is pulled by the trigger. when the contact member after the rotation in conjunction with the operation is moved upward, the engagement to avoid move upward the contact member is more in the middle movement thereof engages the lower end of the lock-out bar A joint is formed.

According to the first aspect of the present invention, when the contact is made , after the trigger is first pulled and the cam plate is rotated, the contact member is pressed against the material to be driven. Move. However, since the lower end of the lockout bar engages with the engaging portion of the cam plate while the contact member moves upward, it cannot move further upward. Therefore, the movable sleeve also stops at a position where it moves upward, and the combustion chamber is not sealed. The trigger cannot be raised any further. That is, the trigger, the movable sleeve, and the contact member are locked. For this reason, the driving tool cannot be activated. Therefore, contact striking can be reliably prevented with a simple structure that only forms the engaging portion on the cam plate, and safety can be ensured.

  In FIG. 1, the code | symbol 1 shows the tool main body 1 of a gas combustion type driving tool (nailing machine). The tool body 1 is made of synthetic resin, and a grip 2 and a magazine 3 are continuously provided, and an impact piston / cylinder mechanism 4 and a combustion chamber 5 are provided inside.

  The striking piston / cylinder mechanism 4 is configured such that a striking piston 7 is slidably accommodated in a striking cylinder 6 and a driver 8 is integrally coupled below the striking piston 7.

  The combustion chamber 5 is formed by an upper end surface 7a of the impact piston 7, an impact cylinder 6, and an annular movable sleeve 10 disposed between an upper wall (cylinder head) 9 formed inside the upper housing. A closed combustion chamber 5 is formed by moving the movable sleeve 10 until it hits the upper wall 9 as shown by an arrow, and the upper portion of the combustion chamber 5 communicates with the atmosphere by moving downward. It is configured.

  The movable sleeve 10 is linked to a contact arm 12 as a contact member via a link member 14. The contact arm 12 is slidably disposed along a nail striking nose portion 13 provided below the tool body 1, and its tip protrudes from the nose portion and is spring-biased so as to always protrude, and the upper end is a link member 14 is attached continuously.

  By the way, a lockout bar 17 is formed integrally with the lower portion of the link member 14. The lower part of the lockout bar 17 is formed in a U shape (see FIG. 3).

  Incidentally, a box-shaped guide portion 16 for slidably guiding the trigger 15 is provided at the base portion of the grip 2 of the tool body. A trigger switch 18 that can be pressed by pulling the trigger 15 in one direction is disposed at one end of the upper wall of the guide portion 16.

  As shown in FIG. 2, the trigger 15 is made of synthetic resin, and is divided into a J-shaped trigger lever 15a disposed opposite to the trigger switch 18 and a trigger body 15b formed in a block shape. .

  At the lower end of the trigger main body 15b, a finger hooking portion 19 for hooking a finger during operation is formed, and a spring receiving groove 20 is formed, and the spring receiving groove 20 is opened above the opposite side of the finger hooking portion 19. . Further, a spring receiving piece 21 is formed to extend on one end side of the finger hanging portion 19. The end portion of the spring 22 disposed in the spring receiving groove 20 of the trigger main body 15b is engaged with the spring receiving concave portion 23 of the upper wall 16a of the guide portion 16.

  A protrusion 25 is formed on the upper end of the trigger lever 15a. The protrusion 25 is disposed so as to face the trigger switch 18. A spring receiving groove 26 is formed below the protrusion 25, and a connecting spring 24 is disposed between the spring receiving groove 26 and the spring receiving piece 21. Further, an arm portion 27 is formed at the lower portion of the trigger lever 15a, and a protruding shaft 28 is formed at the lower end thereof. The protruding shaft 28 is engaged with the cam plate 30.

  The cam plate 30 is formed in a substantially triangular shape and is disposed at a side position of the lockout bar 17. Further, it is rotatably provided on a support shaft 31 provided in the tool body 1. An engaging groove 32 is formed on the outer edge, and the engaging groove 32 is engaged with the protruding shaft 28. As a result, the cam plate 30 is rotatable about the support shaft 31 in conjunction with the vertical movement of the trigger 15.

  The inner edge 33 of the cam plate 30 is disposed so as to face the outside of the lockout bar 17. An engagement groove 35 that can be engaged with the lower end 34 of the lockout bar 17 is formed in the inner edge 33.

  When the contact arm 12 moves to the upper moving end, the lower end 34 of the lockout bar 17 is configured to be positioned above the rotation locus of the upper edge portion 36 of the cam plate 30. Therefore, the cam plate 30 cannot be rotated because the lockout bar 17 interferes, but after the contact arm 12 is moved upward, the cam plate 30 can be rotated by pulling the trigger 15. .

  When operating the driving tool having the above-described configuration, the contact arm 12 is usually moved up relatively by first pressing the nose portion 13 of the nailing machine against the upper surface of the driven material P. As a result, the link member 14 is pushed up against the spring bias, and as shown in FIG. 4, the movable sleeve 10 moves upward, the combustion chamber 5 is shut off from the atmosphere and sealed, and a combustible gas is contained inside. Is injected, and the fan 37 rotates to stir the mixed gas of combustible gas and air. When the contact arm 12 moves up, the lockout bar 17 moves up together with the link member 14 at the same time. Thereafter, when the trigger body 15b is pulled and pulled, the trigger lever 15a is also moved upward by the connecting spring 24, so that the cam plate 30 is rotated counterclockwise as shown in FIG. It moves to the lower part of the lockout bar 17 that is moving up. At the same time, the trigger 15 presses the trigger switch 18 to be turned on, and the mixed gas is ignited by the spark plug 38 and combusts explosively. Therefore, the pressure of the combustion gas drives the striking piston 7 and the driver 8 The leading nail N supplied into the nose portion 13 is struck and driven into the workpiece P.

  When the striking piston 7 is driven downward, the movable sleeve 10 also receives a force to move downward, but when the lower end of the contact arm 12 is pressed against the surface of the workpiece P, the movable sleeve 10 It does not move downward. However, since the tool is separated from the workpiece P due to the reaction of the nail driving, the movable sleeve 10 can move downward. However, since the upper edge 36 of the cam plate 30 is located at the lower end of the lower end of the lockout bar 17 to support the lockout bar 17, the lockout bar 17 cannot move downward. For this reason, the movable sleeve 10 is also held at the same position.

  When the trigger 15 is released and returned to the lower position after the nail driving, the cam plate 30 simultaneously rotates in the reverse direction. For this reason, there is nothing obstructing the movement below the lockout bar 17, so that the contact arm 12, the link member 14, the lockout bar 17, and the movable sleeve 10 are separated when the contact arm 12 is separated from the driven material. The combustion chamber 5 is opened by returning to the lower initial position, and the next nail driving is prepared.

  On the other hand, in the case of contact hitting in which the nose portion 13 is pressed against the driven material P and driven after the trigger 15 is first pulled instead of the single shot as described above, as shown in FIGS. When the contact arm 12 is pressed against the driven material P while pulling the trigger 15 and rotating the cam plate 30, the lockout bar 17 slides upward along the inner edge of the cam plate 30 together with the link member 14. I will do it. However, since an engagement groove 35 is formed in the middle of the inner edge 33, the lower end 34 of the lockout bar 17 engages with the engagement groove 35 and cannot move further upward. Therefore, the movable sleeve 10 also stops at the midpoint of moving upward. That is, the trigger 15 cannot be raised further. The contact arm 12 cannot be moved any further upward. The trigger 15, the movable sleeve 10, and the contact arm 12 are locked. For this reason, the driving tool cannot be activated.

  Therefore, contact striking can be reliably prevented at low cost by a simple structure in which the engagement groove 35 is formed in the cam plate.

  The engaging portion that engages with the lower end of the lockout bar 17 is not limited to a groove shape such as an engaging groove. It may be formed in a protruding shape.

  In the embodiment, the contact arm 12 which is a separate body from the nose portion 13 has been described. However, a contact nose integrated with the nose portion may be used.

It is a longitudinal cross-sectional view which shows the principal part at the time of non-operation of a gas combustion type nailer. It is an enlarged view of the principal part of the contact strike prevention mechanism which concerns on this invention. It is a perspective view of the principal part of the said contact hit prevention mechanism. It is a partial expanded sectional view at the time of the action | operation of the said gas combustion type nailer. It is an enlarged view which shows the state which a cam plate engages with a lockout bar and prevents a contact strike.

Explanation of symbols

10 movable sleeve 12 contact arm 15 trigger 17 lockout bar 18 trigger switch 30 cam plate

Claims (1)

A striking cylinder having a striking piston slidable in the vertical direction and a nail driving nose provided at the bottom of the tool body are slidable, and its lower end protrudes from the lower end of the nose. The contact member arranged in this manner and a movable sleeve arranged to be movable up and down on the striking cylinder, the movable sleeve and the contact member are interlocked, and the contact member is pressed against the material to be driven. It is possible to form a sealed combustion chamber by moving the movable sleeve upward,
By operating the trigger for starting and explosively burning the mixed gas in the combustion chamber, the impact piston is impacted to drive the fastener supplied to the nose part, and
The lateral position of the lockout bar provided integrally with the lower portion of the movable sleeve, the cam plate that rotates in conjunction with the start-up trigger and assignments, the trigger after the movable sleeve is moved upward In the gas combustion type driving tool for holding the movable sleeve so that the movable sleeve does not move downward by moving the cam plate rotated in conjunction with the trigger when the pulling operation is performed,
When the contact member is moved upward after the cam plate is rotated in conjunction with the pulling operation of the trigger, the cam plate is engaged with the lower end of the lockout bar during the movement. A contact striking prevention mechanism for a gas combustion type driving tool , wherein an engaging portion is formed to prevent the contact member from moving further upward .

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