JP2009039801A - Gas combustion type driving tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the circulation of combustion gas when a combustion chamber is opened. <P>SOLUTION: This gas combustion type driving tool is constituted to provide a movable housing 11 between a striking cylinder 7 and a cylinder head 10, to provide the combustion chamber 5 in an openable/closable manner in the movable housing 11, to provide a cylindrical sleeve 14 in the movable housing to form an annular space 15 between the movable housing 11 and the sleeve 14, to form an upper opening 16 and a lower opening 17 to penetrate upper and lower parts of the sleeve 14, respectively, and to circulate a mixed gas of air and fuel gas in the combustion chamber from the lower opening to the annular space 15 and further from the upper opening 16 into the combustion chamber 5, wherein a baffle wall 23a preventing the flow of combustion gas from the annular space 15 to the upper opening 16 is provided between the movable housing 11 and the movable sleeve 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas internal combustion type driving tool for driving a nail such as a general nail or a driving screw, and more particularly to an improved structure of the combustion chamber.

  Conventionally, the combustion chamber has been provided with a movable housing part, and the movable housing part opens and closes the combustion chamber in conjunction with the operation of the contact member, and supplies the combustible gas into the combustion chamber when the combustion chamber is closed. Combustible gas and air are mixed by the rotation of the rotating fan, and the mixed gas is ignited and burned explosively, and high pressure gas pressure is applied to the striking piston for nailing. A gas internal combustion nailing machine that sucks in and exhausts from the bottom of the striking cylinder is already well known (see, for example, Patent Document 1).

  Further, a head valve type gas internal combustion nailing machine has been proposed as an improved version of the gas internal combustion nailing machine having the combustion chamber described above, that is, for some reason the return of the hammering piston after the nail driving is completed. However, the striking piston may return only halfway, and the actual expansion of the combustion chamber volume may cause the fuel to become lean and fail to ignite. And a valve mechanism for opening and closing the partitioning portion for partitioning the impacting cylinder and the combustion chamber, and maintaining the volume of the combustion chamber at a constant level even in the event of occurrence to prevent fuel dilution and proper ignition. There has also been proposed a head valve type gas internal combustion nailing machine which can drive the striking piston while securing the state (Japanese Patent Application No. 2006-216831).

  However, in the agitating drive of the rotary fan in the combustion chamber, there is a stagnation part where the air current is weak in the vicinity of the central part of the lower part of the rotary fan, and the combustion speed of this part becomes slow, which causes incomplete combustion of the gas mixture. Combustion efficiency may be reduced. Further, since the guide and the seal in the operation of the movable housing of the combustion chamber are formed as separate parts above and below the housing portion, the axial center is liable to be displaced, thereby increasing the operating load of the movable housing of the combustion chamber. And seal failure may occur.

Therefore, a cylindrical sleeve is formed between the movable housing and the rotary fan, an annular space is formed between the movable housing and the sleeve, and an upper opening and a lower opening are formed at the upper and lower portions of the sleeve, respectively. Has been proposed (Japanese Patent Application No. 2007-96165). According to this, the mixed gas of air and fuel gas in the sealed combustion chamber is sent from the lower opening to the annular space by the rotating fan provided in the combustion chamber, and further returned to the combustion chamber from the upper opening. The mixed gas is well stirred and mixed by this circulating flow. The mixed gas is ignited and explosively burned, and the fastener is driven out by this combustion pressure. After that, when the movable housing moves up and the combustion chamber is opened, the combustion gas is discharged downward from the lower portion of the combustion chamber, and at the same time, fresh air is introduced from the upper portion of the combustion chamber. is there.
Japanese Examined Patent Publication No. 4-48589

  However, part of the mixed gas combusted in the combustion chamber circulates when the combustion chamber is opened in the same manner as before the opening. Accordingly, a part of the combustion gas moves from the lower opening of the sleeve to the annular space, and further from the upper opening to the upper part of the combustion chamber, so that a phenomenon of mixing with fresh air introduced from the outside occurs. As described above, scavenging performance is lowered, which has a problem of adversely affecting the next stage combustion.

  The present invention solves the above-mentioned problems, and circulates the mixed gas well in a closed combustion chamber to improve the stirring and mixing, and can prevent the combustion gas from circulating when the combustion chamber is opened. It is an object of the present invention to provide a combustion type driving tool.

  In order to solve the above-mentioned problem, the invention according to claim 1 is provided such that a cylindrical movable housing is movably provided between a striking cylinder that slidably houses a striking piston and a cylinder head provided above the striking cylinder. The combustion chamber can be opened and closed inside the movable housing, and a cylindrical sleeve is provided inside the movable housing to form an annular space between the movable housing and the sleeve. Each of the upper opening and the lower opening is formed so as to penetrate, and the mixed gas of air and fuel gas in the combustion chamber is sent from the lower opening to the annular space and further circulated into the combustion chamber from the upper opening. In the gas internal combustion type driving tool to be mixed, the flow of combustion gas from the annular space portion to the upper opening portion is provided between the movable housing and the movable sleeve. Characterized in which a baffle wall which inhibit.

  According to a second aspect of the present invention, in the first aspect of the present invention, the baffle wall is formed to protrude outward from the upper portion of the sleeve.

  According to a third aspect of the present invention, in the first aspect of the present invention, the baffle wall is formed so as to protrude from the inside of the upper portion of the movable housing.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the baffle wall is formed by a narrowed portion that narrows an upper portion of the movable housing.

  According to the present invention, the air and the fuel gas are returned to the combustion chamber from the annular space through the upper opening through the lower opening of the sleeve. Mixed. In addition, a baffle wall is provided between the movable housing and the movable sleeve so as to inhibit the flow of combustion gas from the annular space portion to the upper opening when the movable housing is movable. When is opened, the combustion gas in the annular space is prevented from flowing from the baffle wall to the upper opening. Therefore, the combustion gas is not mixed with fresh air, and combustion can always be ensured satisfactorily.

  Hereinafter, an embodiment of the present invention will be described based on a gas combustion type nailer.

  1 and 2, reference numeral 1 indicates a body of a gas combustion type nailer. The body 1 is provided with a grip 2 and a magazine (not shown), and is provided with a striking piston / cylinder mechanism 4 and a nose portion 6 for striking a nail. The nose portion 6 opens at the front end of the magazine.

  The striking piston / cylinder mechanism 4 is configured such that a striking piston 8 is slidably accommodated in a striking cylinder 7 and a driver 9 is integrally coupled below the striking piston 8.

  A combustion chamber 5 is formed in the upper part of the striking piston / cylinder mechanism. The combustion chamber 5 is formed by the upper end face of the impact piston 8, the impact cylinder 7, the upper cylinder head 10 and a movable housing 11 disposed between them, and the movable housing 11 is formed as shown in FIG. By moving it downward, the upper part of the combustion chamber 5 communicates with the atmosphere, and by moving it upward as shown in FIG. 2, the upper and lower ends of the movable housing 11 are sealed and sealed by the cylinder head 10 and the striking cylinder 7, respectively. Combustion chamber 5 is formed.

  The movable housing 11 is a cylindrical member formed with a central portion and a lower portion 11a having a large diameter and an upper portion 11b having a small diameter, and is connected to the contact member 12 via a link member (not shown) and is opened by a spring. Is biased to the side.

  The contact member 12 is provided so as to be slidable up and down along the nose portion 6, and its lower end 12 a protrudes from the nose portion 6. Then, by pressing the lower end together with the nose portion 6 against the workpiece, the contact member 12 moves relatively upward in conjunction with this, and the movable housing 11 moves upward via the link member. Thereby, the sealed combustion chamber 5 is formed as shown in FIG. On the contrary, the contact member 12 moves relatively downward by moving the nose portion 6 away from the driven material, the link member and the movable housing 11 move downward by the spring, and the upper and lower ends of the lower moving housing 11. And the combustion chamber 5 is opened to the atmosphere.

  Next, a cylindrical sleeve 14 is provided inside the movable housing 11. Thus, an annular space 15 is formed between the movable housing 11 and the sleeve 14. An upper opening 16 and a lower opening 17 are formed through the upper and lower portions of the sleeve 14, respectively.

  The cylinder head 10 is provided with an injection nozzle 18 communicating with a gas can 13 described later, and an ignition plug (not shown) for igniting and burning the mixed gas. The cylinder head 10 is provided with a motor 20, and the output shaft of the cylinder head 10 agitates the fuel gas injected into the combustion chamber 5 with the air in the combustion chamber 5 so as to have a predetermined air-fuel ratio in the combustion chamber 5. A rotary fan 21 for generating a mixed gas is provided.

  Next, the operation of the gas combustion type nailer configured as described above will be described. First, when driving a nail, the movable housing 11 is moved upward in conjunction with pressing the tip of the contact member 12 against the workpiece. As a result, a sealed combustion chamber 5 is formed as shown in FIG. 2, combustible fuel gas is supplied from the injection nozzle 18 into the combustion chamber 5, and the fuel that is injected into the combustion chamber 5 by rotating the rotary fan 21. The gas is blown downward together with the air, sent from the lower opening 17 of the sleeve 14 to the annular space 15, and further circulated from the upper opening 16 into the combustion chamber 5 to be stirred and mixed to obtain a mixed gas having a predetermined air-fuel ratio. To. When the trigger lever 24 (see FIG. 1) is pulled, the mixed gas is ignited by an ignition plug (not shown) and burns explosively. The combustion pressure generated at this time acts on the striking piston 8 in the striking cylinder 7 to drive the striking piston 8 shockingly, and is supplied into the nose portion 6 by a driver 9 coupled to the lower surface side of the striking piston 8. The nail that has been placed is driven out and driven into the workpiece.

  When the driving is completed, the temperature in the combustion chamber 5 rapidly decreases, so that the upper space of the striking piston 8 that has expanded to the striking cylinder 7 has a negative pressure, so that it will return to its original volume due to the pressure difference from the atmospheric pressure from below. Therefore, the striking piston 8 returns to the top dead center as shown in FIG. When the nailing machine is separated from the driven material, the contact member 12 moves relatively downward, so that the movable housing 11 also moves downward, the combustion chamber 5 is opened to the atmosphere, and fresh air is introduced. At the same time, the combustion gas in the combustion chamber 5 is discharged to the outside through the exhaust hole 22 below the body 1 to prepare for the next operation.

  By the way, a baffle wall is provided between the movable housing 11 and the sleeve 14 to inhibit the flow of combustion gas from the annular space 15 to the upper opening 16 when the movable housing 11 moves downward. As shown in FIGS. 1 and 2, the baffle wall 23 a is formed to protrude from the upper outer peripheral surface of the sleeve 14 in a continuous cylindrical shape in a horizontal flange shape. The baffle wall 23a is disposed immediately below the upper opening 16 and is formed to face the large-diameter portion 11a of the movable housing 11 when sealed. Therefore, when the combustion chamber 5 is sealed, a mixed gas of air and fuel gas is present between the baffle wall 23a and the large-diameter portion of the movable housing 11 as indicated by an arrow in FIG. Since a gap sufficient to flow is formed, the mixed gas circulates smoothly and the flow is not hindered. On the other hand, when the movable housing 11 is moved downward and the combustion chamber is opened, the baffle wall 23a faces the small-diameter portion 11b of the movable housing 11 as shown by an arrow in FIG. The gap between the portion 11b is very small. Therefore, since the flow of the mixed gas from the annular space 15 to the upper opening 16 is hindered, the circulation flow of the combustion gas is not generated. Therefore, the combustion gas is not mixed with fresh air, and combustion can always be ensured satisfactorily.

  Note that the baffle wall of the sleeve 14 has a configuration in which the same portion as the baffle wall 23a is swelled in a mortar shape on the outer peripheral surface of the sleeve 14 itself, as indicated by reference numeral 23b in FIGS. 3 (a) and 3 (b). There may be. In this case, since the downward flow of the mixed gas in the combustion chamber 5 and the upward flow in the annular space 15 are guided along the inclined portion 25 of the baffle wall 23b, the circulation of the mixed gas is performed as described above. 1. Smoother than in the case of FIG.

  Next, the baffle wall may be formed so as not to protrude from the sleeve 14 but to the inside of the upper inner peripheral surface of the movable housing 11 as indicated by reference numeral 23c in FIGS. 4 (a) and 4 (b). . The baffle wall 23c corresponds to the upper portion of the upper opening 16 of the sleeve 14 in a state where the combustion chamber 5 is sealed, and the upper opening 16 of the sleeve 14 in a state where the combustion chamber 5 is moved downward and opened. It is provided at a position corresponding to the lower part.

  According to the above configuration, when the combustion chamber 5 is sealed, a sufficient gap is formed between the baffle wall 23c and the sleeve 14 so that a mixed gas of air and fuel gas flows. The mixed gas circulates smoothly and the flow is not hindered. On the other hand, when the movable housing 11 moves downward and the combustion chamber 5 is opened, the baffle wall 23c moves to a position corresponding to the lower portion of the upper opening 16 of the sleeve 14, so that the baffle wall 23c and the sleeve 14 The gap between is very small. Therefore, since the flow of the mixed gas from the annular space 15 to the upper opening 16 is hindered, the circulation flow of the combustion gas is not generated. Therefore, the combustion gas is not mixed with fresh air, and combustion can always be ensured satisfactorily.

  Further, as shown in FIGS. 5 (a) and 5 (b), the baffle wall may be formed by a constricted portion that narrows the upper inner peripheral surface of the movable housing 11, as shown by reference numeral 23d. Good. That is, the movable housing 11 has a shape in which the central portion and the lower portion 11a have a large diameter and the upper portion has a small diameter, and the small diameter portion 11b as the baffle wall 23d has an upper opening portion 16 of the sleeve 14 in a state where the combustion chamber 5 is sealed. Is provided at a position corresponding to the lower portion of the upper opening 16 of the sleeve 14 in a state where the combustion chamber 5 is opened.

  According to the above configuration, when the combustion chamber 5 is in a sealed state, a mixed gas of air and fuel gas is present between the small diameter portion 11b and the sleeve 14 as shown in FIG. Since a gap sufficient to flow is formed, the mixed gas circulates smoothly and the flow is not hindered. On the other hand, when the movable housing 11 moves downward and the combustion chamber 5 is opened, the small diameter portion 11b corresponds to the lower portion of the upper opening portion 16 of the sleeve 14 as shown in FIG. Therefore, the gap between the small diameter portion 11b and the sleeve 14 becomes very small. Accordingly, since the flow of the mixed gas from the annular space 15 to the upper opening 16 is hindered, a circulation flow of the combustion gas is not generated, and the combustion gas is not mixed with fresh air.

  In addition, the form of the baffle wall of this invention is not limited to the above-mentioned thing. As long as the movable housing moves up and down, the space between the movable housing and the sleeve may be wider or narrower than the upper opening of the sleeve.

  Moreover, although the baffle wall has a continuous cylindrical shape on the outer peripheral surface of the sleeve or the inner peripheral surface of the movable housing, it may have an intermittent cylindrical shape. In the above-described embodiment, the movable sleeve that moves up and down has been described. However, the movable sleeve may be opened and closed by rotating. Moreover, in the said embodiment, although it circulates in a combustion chamber with a rotary fan, you may utilize a supercharger etc. Furthermore, in the above embodiment, the gap between the baffle wall and the movable housing or sleeve is very small when the combustion chamber is opened, but it may be set so that there is almost no gap.

The longitudinal cross-sectional view of the principal part of the gas internal combustion type nail driver of embodiment of this invention Longitudinal sectional view of the main part of the nailing machine showing a state in which the combustion chamber is sealed (A) (b) is an expanded sectional view of the principal part at the time of closing and opening of the combustion chamber of the nailing machine showing another form of the baffle wall (A) (b) is an expanded sectional view of the principal part at the time of closing and opening of the combustion chamber of the nailing machine showing still another form of the baffle wall (A) (b) is an expanded sectional view of the principal part at the time of closing and opening of the combustion chamber of the nailing machine showing another form of the baffle wall

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Combustion chamber 7 Blowing cylinder 10 Cylinder head part 11 Movable housing 14 Sleeve 16 Upper opening part 17 Lower opening part 21 Rotating fan 23a, 23b, 23c Baffle wall

Claims (4)

A cylindrical movable housing is movably provided between a striking cylinder that slidably accommodates a striking piston and a cylinder head provided above the striking piston, and a combustion chamber can be opened and closed inside the movable housing. A cylindrical sleeve is provided inside the movable housing to form an annular space between the movable housing and the sleeve, and an upper opening and a lower opening are formed through the upper and lower portions of the sleeve, respectively. In the gas internal combustion type driving tool for stirring and mixing by sending a mixed gas of air and fuel gas in the combustion chamber from the lower opening to the annular space and further circulating from the upper opening into the combustion chamber,
A gas internal combustion type driving tool characterized in that a baffle wall that inhibits the flow of combustion gas from the annular space portion to the upper opening portion is provided between the movable housing and the movable sleeve.   The gas internal combustion type driving tool according to claim 1, wherein the baffle wall is formed to protrude outward from the upper portion of the sleeve.   2. The gas internal combustion type driving tool according to claim 1, wherein the baffle wall is formed so as to protrude from an upper side of the movable housing.   2. The gas internal combustion type driving tool according to claim 1, wherein the baffle wall is formed by a narrowed portion that narrows an upper portion of the movable housing.

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