JP5098448B2 - Pneumatic tool - Google Patents

Description

  The present invention relates to a pneumatic tool, and more particularly to a pneumatic tool that keeps the overall height low and simplifies the exhaust structure to improve exhaust.

  Pneumatic tools such as nailers and screwdrivers are driven by driving a cylinder / piston mechanism using compressed air as a power source. After the driving operation, the compressed air must be exhausted. There are various structures as a conduit in the exhaust system. For example, an exhaust pipe formed with a pipe separately from the tool body is known (see Patent Document 1). In addition, a pneumatic tool employing a head valve is known that has a pipe structure that guides and discharges exhaust gas to the side of the tool through an exhaust hole at the top of the head valve (see Patent Document 2). Further, it is also known that the exhaust pipe line is rear exhausted from the grip by adopting a movable cylinder structure.

  By the way, recent pneumatic tools have a tendency to increase output by using compressed air of ultra-high pressure (maximum operating pressure of 4 to 4.2 MPa or less) as a power source. If an ultra-high pressure can be used, a large output can be obtained, so the tool body can be miniaturized, and the effect of facilitating handling and operation can be expected. It becomes. For example, the exhaust system of a pneumatic tool is also required to have a function for using ultra-high pressure, and it is necessary to select and improve an optimal exhaust pipe for this purpose. In the exhaust pipe composed of the pipe of the pneumatic tool of the invention described in Patent Document 1 described above, the pipe pipe has a unique problem that the exhaust efficiency is low due to an increase in pipe resistance, When the exhaust gas is exhausted, the exhaust pressure becomes considerably high and the exhaust amount increases, so how to deal with this becomes a problem.

  In addition, air supply devices such as air compressors that supply compressed air compress air in the atmosphere, so that moisture in the atmosphere is taken into the air tank, and further inside the air chamber of the pneumatic tool via the air hose. fed, this will be included in the exhaust gas. However, when the ultra-high pressure exhaust gas is discharged from the exhaust port, the air is cooled by adiabatic expansion, so that moisture in the exhaust gas may cause a freezing phenomenon. If the moisture freezes, the cross-sectional area of the exhaust pipe is reduced by that amount, so that the flow of exhaust gas is worsened, and the pipe resistance is further increased, which may cause a defective return of the striking piston. Therefore, improvements are needed to use ultra-high pressure compressed air.

Thus, in order to cope with the use of ultra-high pressure, it is conceivable to increase the exhaust capacity by increasing the pipe diameter or providing a plurality of pipes, for example. In addition, when using ultra-high pressure, it is necessary to introduce an anti-freezing device for preventing the freezing phenomenon of moisture in the exhaust gas by adiabatic expansion at the exhaust port.
JP 2003-236768 A JP-A-8-336768

  However, such a countermeasure results in an increase in the weight of the tool, an increase in the number of parts and a complicated structure, and an increase in cost.

  The present invention solves the above-mentioned problems, makes it possible to reduce the overall size of the tool body by reducing the overall height of the tool body, and to give special measures to the structure of the exhaust pipe line and the arrangement of the exhaust ports in the exhaust system. It is an object of the present invention to provide a pneumatic tool capable of reducing exhaust resistance and effectively preventing problems such as freezing due to adiabatic expansion of exhaust.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a striking cylinder in a tool body, a striking piston slidably accommodated in the striking cylinder, a driver integrally coupled to the striking piston, and the striking A bumper that receives the lower surface of the impact piston at the lower end of the cylinder, an air chamber that supplies compressed air to the upper end open portion of the impact cylinder, and a main valve that opens and closes the compressed air in the air chamber with respect to the impact cylinder. In a pneumatic tool provided with a nose part having an injection port for guiding the driver and injecting a fastener at the lower part of the tool body, the main valve is arranged on the outer peripheral side of the upper end part of the impact cylinder, and the impact A cylinder housing is provided on the outer periphery of the cylinder, and an annular exhaust space is provided along the side of the cylinder housing. The air path is formed, in communication with the upper end of the striking cylinder from between the upper and striking cylinder and the main valve of the exhaust path, to connect the lower portion of the exhaust passage to the exhaust port opened to the outside of the tool body, the exhaust The lower end of the path is connected to an exhaust pipe line bent substantially at right angles to the exhaust path in the vicinity of the bumper, and a filter is attached to the bent portion .

The invention according to claim 2 is the sponge filter according to claim 1, wherein the filter absorbs moisture .

According to a third aspect of the present invention, in the first or second aspect , the outside of the exhaust port is covered with an exhaust cover with a filter.

  According to the first aspect of the present invention, the main valve that opens and closes the compressed air in the air chamber with respect to the striking cylinder is disposed on the outer peripheral side of the upper end portion of the striking cylinder, so that the main valve is disposed above the conventional striking cylinder. it is possible to suppress the total height lower than that of the arrangement configuration. Therefore, it is possible to further reduce the size of the entire tool.

  Further, since the cylinder housing is provided on the outer periphery of the impact cylinder and the exhaust passage having the annular exhaust space is formed along the side of the cylinder housing, the volume of the exhaust passage is larger than that of a normal exhaust pipe. . Therefore, the exhaust from the upper open end of the striking cylinder is exhausted from the annular space having a large volume, and the exhaust resistance is small and the exhaust is performed quickly, so that the return operation of the striking piston is performed smoothly and quickly. Is called. Therefore, strong enough to bear the use of ultra-high pressure.

  Furthermore, since the exhaust path is provided along the side of the cylinder housing, it is not necessary to form an exhaust path in the tool body. For this reason, the tool body has a simple structure and sufficient pressure resistance can be secured even at ultra-high pressure, and it is not necessary to process the cylinder cap etc. of the tool body for exhausting so that a part protrudes outward. Direction is lost. Therefore, since the structure fixed with a volt | bolt etc. can also be employ | adopted easily, attachment property improves.

In addition , since the exhaust port of the exhaust passage is disposed near the bumper that tends to become hot because it receives an impact on the lower surface of the striking piston at the lower end of the striking cylinder, cooling due to adiabatic expansion of the exhaust discharged from the exhaust port Thus, the occurrence of the phenomenon that the exhaust port freezes can be effectively suppressed, and thus the occurrence of defects such as a return failure due to freezing can be eliminated. In addition, since the bumper temperature rise is suppressed by cooling the exhaust, thermal damage to the bumper can be suppressed. In this way, the two problems affect each other so that the durability can be improved.

Further , the lower end of the exhaust path is connected to an exhaust pipe line bent substantially at right angles to the exhaust path in the vicinity of the bumper, and a filter is attached to the bent part. Moisture is easily trapped by the filter at the bent portion. Then, the filter is heated by the rise in the temperature of the bumper, and moisture in the exhaust gas passing through the filter is evaporated and removed, so that the freezing phenomenon at the exhaust port is more effectively prevented.

According to the invention of claim 3 , since the outside of the exhaust port is covered with the exhaust cover with the filter, the exhaust pressure is reduced, and the exhaust sound is reduced. Improvement is achieved.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  The nailing machine shown in FIGS. 1 to 3 is a pneumatic tool of an ultra-high pressure specification, and is provided with a drive unit composed of a striking cylinder 2 and a striking piston 3 in a tool body 1, and a driver 4 is integrated with the striking piston 3. The nail supplied to the injection part in the nose part 5 of the tool body 1 of the nailing machine is driven out by the driver 4 by driving the striking piston 3.

  The tool body 1 of the nailing machine is formed with an air chamber 7 for storing compressed air supplied from a compressed air supply source such as a compressor (not shown) via a grip portion 6, and is activated by operating a trigger lever. When the valve 8 (which may be a known one) is operated, a main valve 10 which will be described later is operated, and the air chamber 7 is opened with respect to the upper end open portion of the impact cylinder 2 so that compressed air is blown in the impact cylinder 2. It is supplied to the upper surface of the piston 3, whereby the striking piston 3 is moved downward so that the driver 4 strikes and hits the nail.

  The tool body 1 includes an upper body 1a and a lower body 1b. The upper body 1a is in a closed state with an upper portion opened to form a cylinder cap, and the lower body 1b has a cylindrical shape with an upper portion and a lower portion opened. None, the upper and lower bodies have the lower outer periphery of the upper body 1a fitted into the inner periphery of the large opening above the lower body 1b.

  The main valve 10 is disposed on the outer peripheral side of the upper end of the impact cylinder 2 so as to be movable up and down. Usually, it is biased upward by the spring force of the spring 11 and is at the top dead center position, and shuts off the air chamber 7 and the upper end open portion of the striking cylinder 2. When the start valve 8 is actuated by operating the trigger lever, the compressed air in the lower chamber 12 of the main valve 10 is exhausted, so that the air pressure acting on the upper end surface of the main valve 10 rather than the spring force of the spring 11 is exhausted. The main valve 10 moves downward (see FIGS. 3 and 5). Thereby, as described above, the compressed air in the air chamber 7 opens with respect to the upper end open portion of the striking cylinder 2, and the compressed air is supplied to the upper surface of the striking piston 3 in the striking cylinder 2.

  Next, the impact cylinder 2 is arranged inside the tool body 1, and a cylindrical bumper storage portion 13 is provided below the impact cylinder 2, and the bumper storage portion 13 receives the lower surface of the impact piston 3. An annular bumper 14 for reducing the impact of the striking piston 3 is arranged. A cylindrical cylinder housing 15 is concentrically disposed on the outer periphery of the impact cylinder 2. The cylinder housing 15 includes an upper cylinder housing 15a and a lower cylinder housing 15b, and a blowback chamber 16 is provided between the lower cylinder housing 15b and the striking cylinder 2. The blowback chamber 16 is a compressed air in which a part of the air compressed below the striking piston 3 is sent out from the communication hole 17 (with a check valve) of the striking cylinder 2 when the striking piston 3 is driven downward. Is configured to act on the lower surface of the striking piston 3. The compressed air for driving supplied above the striking piston 3 after exhausting is exhausted, so that the pressure of the compressed air against the upper and lower surfaces of the striking piston 3 is reversed, and the striking piston 3 is returned to the top dead center. To make it happen.

  Next, an exhaust path 18 having an annular exhaust space is formed along the side of the cylinder housing 15. That is, as shown in FIGS. 1 and 5, an annular upper exhaust passage 18a is formed between the striking cylinder 2 and the upper cylinder housing 15a, and also between the lower cylinder housing 15b and the tool body 1. annular lower exhaust passage 18b is formed. Further, an upper end exhaust passage 18 c is also formed between the striking cylinder 2 and the main valve 10 in an annular shape. Since the upper exhaust passage 18a is provided along the inner peripheral side of the upper cylinder housing 15a and the lower exhaust passage 18b is provided along the outer peripheral side of the lower cylinder housing 15b, as shown in FIG. 1 and FIG. the upper exhaust passage 18a has a smaller diameter than the lower exhaust passage 18b. Furthermore, it continues through the space part 20 formed between the lower end part of the upper cylinder housing 15a and the upper end part of the lower cylinder housing 15b.

  When the air chamber 7 is closed as shown in FIG. 1, the upper end exhaust passage 18 c extends from between the impact cylinder 2 and the main valve 10 to the upper end open portion of the impact cylinder 2 as shown in FIG. Communicate. On the other hand, when the main valve 10 moves downward during the driving operation and the air chamber 7 is opened to the striking cylinder 2, the inner upper end 21 of the main valve 10 is placed on the upper outer periphery of the striking cylinder 2 as shown in FIG. Since it contacts the O-ring 22 of the provided annular bulging portion, the upper end exhaust path 18c is blocked.

  Further, as shown in FIG. 6, the lower end portion of the lower exhaust passage 18 b is continuous with the exhaust conduit 24 that opens to the outside of the tool body 1. That is, the lower end portion of the lower exhaust passage 18 b is formed as a slightly wide annular space on the outer peripheral side of the bumper storage portion 13. As shown in FIG. 4C, a plurality of wide portions 23 are formed at intervals in the outer periphery of this space.

  An exhaust pipe 24 is formed through the side wall of the tool body 1, and one end of the exhaust pipe 24 is connected to the lower end of the lower exhaust path 18b. The exhaust pipe 24 is bent at a substantially right angle to the lower exhaust path 18b, and a sponge-like filter 25 that absorbs moisture is attached to the bent portion. An exhaust cover 27 is attached to the open end of the exhaust port 26 at the end of the exhaust conduit 24. Filters 28 are attached to the lower end of the lower exhaust passage 18b and the inside of the exhaust cover 27, respectively.

  Here, the operation of the nailing machine which is the pneumatic tool of the present embodiment will be described.

  When the start valve 8 is operated by operating the trigger lever for driving the nail, the compressed air in the lower chamber 12 of the main valve 10 is exhausted from the start valve 8 through the air line 29 as shown in FIG. The compressed air in the air chamber 7 acts on the upper surface of the main valve 10, and the main valve 10 opens downward against the spring 11 as shown in FIGS. 3 and 5. Compressed air is supplied into the striking cylinder 2, and the striking piston 3 is driven to perform nail driving. Thereafter, when the trigger lever is released, compressed air is supplied to the lower chamber 12 of the main valve 10 through the air line 29 by the operation of the start valve 8, so that the difference in force with respect to the upper and lower sides of the main valve 10 is reversed. valve 10 is actuated to close upward as in FIG. At the same time, the upper end exhaust passage 18c is unblocked, and the compressed air in the impact cylinder 2 passes through the upper end exhaust passage 18c, the upper exhaust passage 18a, and the lower exhaust passage 18b from the upper end open portion, and further passes through the exhaust pipe 24. The air is exhausted from the exhaust port 26.

  Further, when the compressed air in the striking cylinder 2 is discharged by the exhaust operation, the air pressure with respect to the upper surface of the striking piston 3 is reduced in the striking cylinder 2. Since the compressed air from 16 acts, the differential pressure with respect to the upper and lower surfaces of the striking piston 3 is reversed, and the striking piston 3 returns and is ready for the next nailing.

  Since the nailing machine has the above-described configuration, the following operational effects can be obtained.

  First, since the main valve 10 for opening and closing the compressed air in the air chamber 7 with respect to the striking cylinder 2 is arranged on the outer peripheral side of the upper end portion of the striking cylinder 2, it is arranged above the striking cylinder 2 as in the prior art. it can be compared to reduce the overall height low.

  Furthermore, since the exhaust path 18 is provided along the side of the cylinder housing 15, it is not necessary to form the exhaust path 18 in the cylinder cap. For this reason, the cylinder cap does not require directionality, has a simple structure, can secure a sufficient withstand pressure even at an ultrahigh pressure, and can be fixed with a bolt or the like, so that the mounting property is also improved.

  In addition, a cylinder housing 15 is provided on the outer periphery of the impact cylinder 2 and exhausted from an exhaust passage 18 having an annular exhaust space formed along a side portion of the cylinder housing 15. Since the volume of the exhaust passage 18 is large, the exhaust resistance is small and exhaust is performed quickly, so that the return operation of the striking piston 3 is performed smoothly.

  Furthermore, the compressed exhaust gas is suddenly released to the atmosphere, so that it is adiabatically expanded and rapidly cooled, and moisture in the exhaust gas may be frozen. Also in the above embodiment, since the exhaust port 26 is open to the atmosphere, the temperature rapidly decreases due to adiabatic expansion. However, the lower end of the exhaust passage 18 and the exhaust port 26 are located in the vicinity of the bumper 14 and the blowback chamber 168. Since the vicinity of the exhaust port 26 becomes hot due to the temperature rise of the bumper 14 and the temperature rise due to adiabatic compression of the air in the blowback chamber 16, the freezing phenomenon in the exhaust path 18 can be effectively suppressed. Therefore, the occurrence of problems such as return failure due to freezing is eliminated, and the temperature rise of the bumper 14 is suppressed by cooling the exhaust gas, so that the heat damage of the bumper 14 is suppressed. In this way, the two problems affect each other so that the durability can be improved.

  The lower end of the exhaust passage 18 is connected to an exhaust conduit 24 bent substantially at right angles to the exhaust passage 18 in the vicinity of the bumper 14, and a sponge-like filter 25 is attached to the bent portion. Therefore, the moisture contained in the exhaust gas is easily captured by the filter 25 at the bent portion. The filter 25 is heated by the temperature rise of the bumper 14 and the moisture in the exhaust gas passing through the filter 25 is evaporated and removed, so that the freezing phenomenon at the exhaust port 26 is more effectively prevented. Therefore, it is possible to effectively prevent the occurrence of a malfunction due to a defective return operation due to the freezing of the exhaust passage 18.

  Since the outside of the exhaust port 26 is covered by an exhaust cover 27 with a filter 28, the exhaust pressure is reduced by the filter 28, the exhaust sound is reduced, and the safety in using the tool is improved. It is done.

  As mentioned above, the higher the air pressure used, the more serious the problems of pressure resistance, displacement, and moisture freezing. It is suitable as a thing.

  The embodiment of the pneumatic tool described above is for punching out a nail, but is not limited to this, and includes a fastener such as a driving screw.

Side view of the nailing machine of the present invention Enlarged sectional view of A-A line of FIG. 1 Enlarged cross-sectional view of line B-B in FIG. 2 (A), (b), and (c) are cross-sectional views along the lines XX, YY, and ZZ in FIG. 2, respectively. 3 is an enlarged view of the upper part of FIG. Enlarged view at the bottom of Figure 2

1 Tool body 2 Blowing cylinder 10 Main valve 15 Cylinder housing 18 Exhaust passage 26 Exhaust port

Claims (3)

A striking cylinder in the tool body, a striking piston slidably accommodated in the striking cylinder , a driver integrally coupled with the striking piston, a bumper receiving the lower surface of the striking piston at the lower end of the striking cylinder, An air chamber that supplies compressed air to the upper end open portion of the impact cylinder, and a main valve that opens and closes the compressed air in the air chamber with respect to the impact cylinder are provided. In a pneumatic tool provided with a nose portion having an injection port for injecting
The main valve is disposed on the outer peripheral side of the upper end portion of the impact cylinder, a cylinder housing is provided on the outer periphery of the impact cylinder, and an exhaust path having an annular exhaust space is formed along the side portion of the cylinder housing, the upper portion of the exhaust path communicates with the upper end of the striking cylinder from between the striking cylinder and the main valve, the lower portion of the exhaust passage is connected to the exhaust port opened to the outside of the tool body, the lower end of the exhaust passage, the A pneumatic tool characterized in that it is connected to an exhaust pipe that is bent substantially at right angles to the exhaust path in the vicinity of the bumper, and a filter is attached to the refracting portion . The pneumatic tool according to claim 1, wherein the filter is a sponge filter that absorbs moisture . The pneumatic tool according to claim 1 or 2 , wherein an outside of the exhaust port is covered with an exhaust cover with a filter.

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