JP5125265B2 - Gas fired driving tool - Google Patents

Description

  The present invention explosively burns a mixed gas obtained by stirring and mixing flammable gas and air in a combustion chamber and driving a striking piston / cylinder mechanism to drive out a fastener from the nose portion, and to the nose portion. The present invention relates to a gas combustion type driving tool in which a gas pipe is provided between a feed piston / cylinder mechanism for feeding a fastener and the combustion chamber, and the feed piston / cylinder mechanism is reciprocated by a spring and a combustion gas from the gas pipe.

  As an example of a gas combustion type driving tool, a combustible gas is injected into a combustion chamber sealed in a body, a mixed gas of combustible gas and air is stirred in the combustion chamber, and the stirred mixed gas is mixed in the combustion chamber. Combustion 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 the striking cylinder in an impact manner. 2. Description of the Related Art A combustion gas driven driving machine is known in which a fastener supplied to a nose portion below a body is driven into a steel plate or concrete by a driver coupled to a lower surface side of a piston. In such a combustion gas driven driving machine, a container such as a gas cylinder filled with a combustible gas is installed in the tool, and a battery, which is a power source for igniting the combustible gas, is mounted on the tool. It is possible to perform a driving operation of a fastener such as a nail or a pin without being constrained by a power supply source such as electric power or compressed air.

  The gas combustion type driving tool is provided with a feed mechanism for sequentially feeding the connected fasteners stored in the magazine to the nose portion. As this feed mechanism, a feed claw that is slidably accommodated in a feed cylinder is provided with a feed claw that can be engaged with and disengaged from a connecting fastener accommodated in a magazine, and the feed piston feeds the feed claw to the nose portion side. In general, a feed piston / cylinder mechanism that reciprocates in the retreat direction opposite to the direction is common.

In this case, the feed piston of the feed piston / cylinder mechanism is reciprocated by using the pressure of the combustion gas in the spring and the combustion chamber, and the feed piston is always urged in the nail feed direction by the spring, and the combustion gas is It is known to move the feed piston in the retracting direction against the spring by pressure. In this technique, a metal tube is disposed between a combustion chamber and a feed cylinder, and combustion gas is sent to the feed cylinder through this tube (see Patent Document 1). The tube is provided to crawl along the outside of the striking cylinder.
US Pat. No. 7,040,5

  By the way, when the combustion gas sent to the feed cylinder is cooled, the volume is reduced and the force for holding the feed piston is also reduced. When the holding force of the feed piston is reduced, the feed piston is moved in the fastener feed direction by the spring, so that the leading fastener in the magazine is pushed out into the nose portion. If this is done in the middle of the return of the striking piston after nail driving, the leading fastener pushed out by the spring will come into contact with the driver being returned and will slide, so the striking piston cannot return to top dead center due to its contact resistance. There is a high possibility of failure. Therefore, a sufficient amount of combustion gas needs to be sent from the combustion chamber to the feed cylinder.

  However, since the cross-sectional area of the gas pipeline by a tube is small, it is difficult to send sufficient combustion gas. For this reason, there is a high possibility that the phenomenon of rubbing will occur. An attempt to increase the cross-sectional area is not preferable because the tube diameter increases and the tool itself increases in size.

  An object of the present invention is to provide a gas combustion type driving tool capable of solving the above-mentioned problems and increasing the pipe area of the gas pipe of the combustion gas without increasing the size of the tool.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a combustion chamber that explosively burns a mixed gas obtained by stirring and mixing a combustible gas and air, and sealing and releasing the atmosphere of the combustion chamber. A movable sleeve for switching, a striking piston / cylinder mechanism that causes the striking piston to be driven impactively in the striking cylinder by causing this high-pressure combustion gas to act on the striking piston accommodated in the striking cylinder, and a lower surface of the striking piston A nose portion that slides and guides a screwdriver that is coupled to the side, and a fastener that is engaged in and disengaged from a connecting fastener housed in a magazine. A feed piston / cylinder mechanism that reciprocates, and constantly biases the feed piston in the feed direction so that a part of the combustion gas is sent to the combustion chamber and the feed mechanism. In through the gas line was supplied to the feed cylinder the feed piston driving gas combustion type for actuating the retracting direction against the aforementioned spring tool which is provided between the piston-cylinder mechanism, the movable sleeve The cross section of the gas pipeline in a range where the cylinder slides relative to the striking cylinder is formed in a flat shape, one end of the gas pipeline is directly opened in the combustion chamber, and the other end is connected to the feed cylinder In addition, the gas pipe line formed in a flat shape is integrally formed so as to fit within the wall thickness of the striking cylinder .

  According to the first aspect of the present invention, the cross section of the gas pipe that sends the combustion gas from the combustion chamber to the cylinder is formed in a flat shape. Since the area can be increased, the pipe area of the gas pipe for the combustion gas can be increased without increasing the size. Therefore, a sufficient combustion gas can be sent from the gas pipe to keep the feed piston in the retracted state, and the striking piston can be effectively prevented from being rubbed when returning, and a good return can always be ensured.

In addition , since the gas pipe is formed integrally with the striking cylinder, the gas pipe fits within the wall thickness of the striking cylinder. Therefore, the gas line never protrudes from the blow cylinder, and the cross section of the gas line is formed in an oval shape, so that a sufficient amount of combustion gas is sent and the feed piston is securely held in the retracted state. Can do.

  In FIG. 1, reference numeral 1 denotes a body of a gas combustion type nailer. A grip (not shown) and a magazine 2 are connected to the body 1, and a striking piston / cylinder mechanism 3, a combustion chamber 4, a nose portion 5, a feed piston / cylinder mechanism 6 for feeding nails, Is provided.

  The striking piston / cylinder mechanism 3 is configured such that a striking piston 11 is slidably accommodated in a striking cylinder 10 and a driver 12 is integrally coupled below the striking piston 11. Reference numeral 9 denotes a C retaining ring that restricts the upward movement of the striking piston 11.

  The combustion chamber 4 is formed by the upper end surface of the striking piston 11, the striking cylinder 10, an upper wall 14 (cylinder head) formed inside the upper housing 13, and an annular movable sleeve 15 disposed therebetween. The upper part of the combustion chamber 4 communicates with the atmosphere by moving the movable sleeve 15 downward as shown in FIG. 1, and the sealed combustion chamber 4 is formed by moving upward as shown in FIG. It is configured as follows.

  That is, the movable sleeve 15 is linked to the contact member 16 via a link member (not shown), and is biased to the open side by a spring.

  The contact member 16 is provided so as to be slidable up and down along the nose portion 5, and its lower end 16 a protrudes from the nose portion 5. Then, by pressing the lower end 16a together with the nose portion 5 against the material to be driven, the contact member 16 moves relatively upward in conjunction with this, and the movable sleeve 15 is moved upward via the link member. As a result, a sealed combustion chamber 4 is formed. On the contrary, the contact member 16 moves relatively downward by moving the nose portion 5 away from the material to be driven, the link member and the movable sleeve 15 move downward by the spring, and the combustion chamber 4 is opened to the atmosphere. Is done.

  The cylinder head 14 is provided with an injection nozzle 17 communicating with the gas container and an ignition plug (not shown) for igniting and burning the mixed gas. The upper housing 13 is provided with a motor 18 whose output shaft has a combustible gas injected into the combustion chamber 4 agitated with the air in the combustion chamber 4 and has a predetermined air-fuel ratio in the combustion chamber 4. A rotating fan 19 is provided for generating the mixed gas.

  The nose portion 5 guides the sliding of the driver 12 and opens to the magazine 2.

  The feed piston / cylinder mechanism 6 connects the feed piston 8 slidably received in the feed cylinder 7, engages / disengages the feed claw at the tip of the feed piston 8 with the connecting nail stored in the magazine 2, It is reciprocated in the nail feed direction sent to the nose portion 5 side indicated by the solid line in FIG. 1 and in the opposite retreat direction as indicated by the dotted line in FIG. When the feed piston 8 moves to the moving end in the feed direction, the leading nail N of the connecting nail is pushed into the injection port of the nose portion 5. Therefore, when the feed piston 8 is in the moving end position in the feed direction, the connecting nail does not move, so the leading nail is held in a state of being pressed against the inner wall of the injection port.

  Next, the feed cylinder 7 of the feed piston / cylinder mechanism 6 is provided with a spring 20 that constantly biases the feed piston 8 in the feed direction. On the other hand, the side of the feed cylinder 7 opposite to the spring 20 is connected to the combustion chamber 4 via a gas pipe 21.

  Next, the operation of the gas combustion type nailer configured as described above will be described. First, when driving the nail, the movable sleeve 15 is moved upward by pressing the tip of the contact member 16 against the material to be driven. As a result, a sealed combustion chamber 4 is formed, and a combustible fuel gas is supplied from the injection nozzle 17 into the combustion chamber 4, and the rotary fan 19 rotates and the combustible gas injected into the combustion chamber 4 is converted into the combustion chamber. 4 is agitated with the air in 4 to obtain a mixed gas having a predetermined air-fuel ratio. When the trigger lever (not shown) is pulled, the mixed gas is ignited by the spark plug and burns explosively. The high-pressure combustion gas acts on the striking piston 11 in the striking cylinder 10 to drive the striking piston 11 in an impact manner, and is supplied into the nose portion 5 by the driver 12 coupled to the lower surface side of the striking piston 11. The nail N is driven and driven into the workpiece.

  When the driving is completed, the temperature in the combustion chamber 4 rapidly decreases, so that the upper space of the striking piston 11 that has expanded to the striking cylinder 10 becomes a negative pressure, and returns to the original volume due to the differential pressure from the atmospheric pressure from below. Therefore, as shown in FIG. 1, the striking piston 11 returns to the top dead center. When the nail driver is moved away from the material to be driven, the contact member 16 moves relatively downward, so that the movable sleeve 15 also moves downward, the combustion chamber 4 is opened to the atmosphere, and new air enters. Is ready for operation.

  By the way, the nails in the magazine 2 (not shown) are fed into the nose portion 5 by the feed piston / cylinder mechanism 6. The feed piston / cylinder mechanism 6 is provided in the feed cylinder 7 so that the feed piston 8 can reciprocate, and the feed piston 8 moves in the nail feed direction in which the connecting nail in the magazine 2 is fed to the nose portion 5 side and in the opposite retreat direction. Is configured to move. The feed piston 8 is always biased by a spring 20 in the feed direction. On the other hand, a gas pipe 21 is opened at the end of the feed cylinder 7, and the feed piston 8 is operated in the retracting direction against the spring 20 by the gas supplied from the gas pipe 21. It has become. After the striking piston 11 returns to the top dead center, the gas in the feed cylinder 7 is exhausted, and the feed piston 8 feeds the next nail toward the nose portion 5 by the spring 20.

  The gas pipe 21 is provided between the combustion chamber 4 and the feed piston / cylinder mechanism 6.

  As shown in FIGS. 1 and 2, the gas conduit 21 is integrally formed inside the side wall 22 of the impact cylinder 10. The upper portion 21 a of the gas pipe 21 has a flat cross section, that is, a substantially rectangular shape, but is curved so that the long side 23 follows the curved surface of the inner and outer peripheral surfaces of the striking cylinder 10.

  That is, the striking cylinder 10 is formed by die casting or the like of aluminum or an alloy thereof, and the striking piston 11 is slidably accommodated on the inner peripheral surface thereof, so that the cross section is circular. Further, the upper part of the outer peripheral surface also has a circular cross section because the inner peripheral surface of the lower portion 15a of the movable sleeve 15 slides in the vertical direction. That is, the inner and outer peripheral surfaces of the upper portion of the impact cylinder 10 are circular. Therefore, a flat gas pipe 21a is formed between the inner peripheral surface and the outer peripheral surface in a thick portion. A portion of the striking cylinder 10 where the movable sleeve 15 does not slide is made thick by projecting a part of the outer peripheral surface of the striking cylinder 15 outward, and a gas pipe line 21b having a circular cross section is formed in this portion. The upper gas pipe 21a is continuous with the upper gas pipe 21a. The upper end of the gas pipe 21 is formed so as to face the combustion chamber 4, and the lower end is integrally connected to an end of a pipe 24 having a circular cross section extending from the feed cylinder 7. It is connected to the feed cylinder 7 via

  As described above, since the cross section of the gas pipe 21 for sending the combustion gas from the combustion chamber 4 to the cylinder 7 is formed in a flat shape, the cross sectional area can be increased even if the amount of protrusion is small compared to the case where the cross section is circular. Since it can be increased, the amount of combustion gas supplied to the feed cylinder 7 can be increased by increasing the gas pipe area of the combustion gas without increasing the size. Therefore, a sufficient combustion gas is sent from the gas pipe 21 to hold the feed piston 8 in the retracted state, and the striking piston 11 can be effectively prevented from being slid when returning, and a good return can always be ensured. .

  If the cross-sectional area of the upper part 21a of the gas pipe 21 is made circular, the gas pipe 21 protrudes to the outside as shown by the dotted line in FIG. The inner diameter of the sleeve must be increased.

  Further, since the gas pipe 21 is formed integrally with the striking cylinder 10, the gas pipe hardly protrudes outside the striking cylinder 10, and it is not necessary to form the gas pipe 21 with a separate part. Cost can be kept low.

  In particular, the upper portion of the gas pipe 21 is flattened, and the inner and outer peripheral surfaces of the striking cylinder 10 are circular so that the smoothness of sliding between the striking piston 11 and the movable sleeve 15 is not impaired.

  Note that the end of the gas pipe 21 may be directly connected to the feed cylinder 7.

  Further, the gas pipeline does not necessarily have to be formed integrally with the striking cylinder 10. A tube tube separate from the striking cylinder 10 may be used, and the tube tube may be wound along the outer surface of the striking cylinder 10. In this case, the cross section of the entire tube tube is made flat.

  The driving tool according to the present invention is not limited to a nailing machine. Power can be transmitted by combustion, and it can be applied to a driving tool for sending fasteners such as headed bars (nails, screws) and headless bars (parallel pins).

Longitudinal sectional view showing the main part of the gas combustion nailer when not in operation Sectional view on the XX line of FIG.

2 Magazine 4 Combustion chamber 6 Feeding piston / cylinder mechanism 7 Feeding cylinder 8 Feeding piston 21 Gas line

Claims (1)

A combustion chamber that explosively burns a mixed gas obtained by stirring and mixing flammable gas and air, a movable sleeve for switching between sealing the combustion chamber and opening to the atmosphere, and a cylinder that blows the high-pressure combustion gas A striking piston / cylinder mechanism that acts on the striking piston housed in the striking cylinder by impacting the striking piston and a screwdriver that is coupled to the lower surface side of the striking piston slides and guides the fastener. A feed piston / cylinder mechanism that reciprocates in a nail feed direction in which a nose portion to be driven out and a feed piston that engages and disengages with a connecting fastener housed in a magazine is sent to the nose portion side and a retreat direction in the opposite direction; Is constantly energized in the feed direction, and a part of the combustion gas is supplied to the gas provided between the combustion chamber and the feed piston / cylinder mechanism. In the gas combustion type driving tool for actuating the retracting direction against via the road and supplied to the feed cylinder of the feed piston in the spring,
A cross section of the gas conduit in a range where the movable sleeve slides with respect to the striking cylinder is formed in a flat shape, one end of the gas conduit is directly opened to the combustion chamber, and the other end is fed to the feed chamber. A gas combustion type driving tool characterized in that it is integrally formed so that the gas pipe line connected to a cylinder and formed in a flat shape is accommodated within the wall thickness of the hitting cylinder .

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