JP7070038B2 - Driving tool - Google Patents

Description

The present invention relates to a driving tool that burns a mixed gas of air and fuel and is driven by the combustion pressure.

Conventionally, nailing is provided with a combustion chamber that burns a mixed gas of air and fuel, and a striking mechanism that drives a fastener such as a nail by operating with the combustion pressure generated when the mixed gas is burned in the combustion chamber. A driving tool called a machine is widely used. The driving tool using the combustion pressure is provided with a valve for closing the combustion chamber at the time of burning and opening the combustion chamber for exhausting after driving. Therefore, in this driving tool, the exhaust valve is conventionally configured to close when the contact is turned on.

For example, in Patent Document 1, when the piston / driver assembly is moved from the protruding fastener driving position to the normal retracting position, the cylinder is unidirectionally valved to the atmosphere so as to newly replace the air under the piston / driver assembly. A driving tool is disclosed in which a lower cap is provided with a port means connected via a device.

Japanese Patent Application Laid-Open No. 63-28874

However, the conventional driving tool disclosed in Patent Document 1 has the following problems. That is, in the configuration in which the exhaust valve is opened and the exhaust in the combustion chamber is started by the contact off operation after the driving, the timing of the exhaust is delayed, the combustion gas temperature is lowered, and dew condensation may occur in the combustion chamber. was there.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a driving tool capable of performing an exhaust operation immediately after the end of the fastener driving operation.

The driving tool according to the present invention includes a combustion chamber in which a mixed gas of a compressed oxidant and a fuel burns, a cylinder accommodating a striking mechanism operated by a combustion pressure generated by combustion of the mixed gas in the combustion chamber, and a cylinder. The combustion chamber and the inside of the cylinder are opened to the outside, and the exhaust valve that shuts off the inside and the outside of the combustion chamber and the cylinder, and the exhaust valve are operated based on the pressing operation against the material to be driven to operate the combustion chamber. It also has a contact part for shutting off the cylinder and the outside and enabling the striking mechanism to operate, and the exhaust valve is independent of the contact part when a predetermined load is applied by the operation of the striking mechanism. Configured to work .

In the present invention, when the exhaust valve receives a predetermined load due to the operation of the striking mechanism, the exhaust valve operates independently of the contact portion. Thereby, for example, the exhaust valve can be moved to an open position for opening the exhaust port provided in the combustion chamber and the cylinder in a state where the contact portion is pressed against the material to be driven.

According to the present invention, the exhaust valve can be operated independently of the contact portion when a predetermined load is applied by the driving operation of the striking mechanism, so that the exhaust operation is performed immediately after the driving operation of the fastener is completed. be able to.

It is sectional drawing which shows an example of the nail driving machine of this embodiment. It is sectional drawing which shows an example of the main part structure of the main body part of a nailing machine. It is sectional drawing which shows an example of the main part structure of the main body part of a nailing machine. It is sectional drawing which shows an example of the case where the contact portion in the nail driving machine of this embodiment is off and the exhaust valve is in an open position (No. 1). FIG. 2 is a cross-sectional view showing an example of a case where the contact portion in the nail driving machine of the present embodiment is off and the exhaust valve is in the open position (No. 2). It is a perspective view which shows an example of the main body side of the nail driving machine of this embodiment. It is sectional drawing which shows the operation example when the contact part in the nail driving machine of this embodiment is on, and the exhaust valve is in a closed position (the 1). It is sectional drawing which shows the operation example when the contact part in the nail driving machine of this embodiment is on, and the exhaust valve is in a closed position (the 2). It is sectional drawing which shows the operation example when the contact part in the nail driving machine of this embodiment is on, and the exhaust valve is in an open position (the 1). It is sectional drawing which shows the operation example when the contact part in the nail driving machine of this embodiment is on, and the exhaust valve is in an open position (the 2).

Hereinafter, an embodiment of a nail driving machine, which is an example of the driving tool of the present invention, will be described with reference to the drawings.

<Structure example of the nailing machine 1A of the present embodiment>
FIG. 1 is an overall configuration diagram showing an example of the nailing machine 1A of the present embodiment. 2A and 2B are diagrams showing an example of the main body configuration of the main body 10. FIG. 3A is a cross-sectional view showing an example of the main body 10 of the nailing machine 1A of the present embodiment, and FIG. 3B is a cross-sectional view taken along the line AA of the nailing machine 1A shown in FIG. 3A. FIG. 4 is a perspective view showing an example of the main body 10 side of the nailing machine 1A of the present embodiment. In FIGS. 1 to 4, the nose portion 12 side of the nailing machine 1A is on the lower side, and the opposite side is on the upper side. Further, in FIGS. 1, 3, and 4, the main body 10 side of the nailing machine 1A is the front, and the battery 17 side on the opposite side is the rear.

As shown in FIGS. 1 to 4, the nailing machine 1A of the present embodiment is a tool for driving a fastener such as a nail into a material to be driven such as wood, gypsum board, steel plate, and concrete. The nailing machine 1A includes a main body portion 10, a handle portion 11 extending from the main body portion 10 and gripped by hand, and a nose portion 12 in which a fastener is punched out on one side of the main body portion 10.

The nailing machine 1A is provided with a tank mounting portion 13 to which a fuel tank (not shown) filled with fuel is detachably attached, in a form substantially parallel to the lower part of the handle portion 11. Further, in the nailing machine 1A, a magazine 14 sharing a fastener with the nose portion 12 is provided below the tank mounting portion 13. Further, in the nailing machine 1A, an air plug 15 to which an air hose to which compressed air is supplied from a supply source such as an air compressor is connected is provided in the tank mounting portion 13 in this example.

Further, in the nailing machine 1A, an operation trigger 16 for operating the nailing machine 1A is provided on the handle portion 11, and a battery mounting portion 18 to which a battery 17 serving as a power source for the nailing machine 1A is attached is provided on the handle portion 11. ..

The nailing machine 1A includes a striking cylinder 2 that operates by the combustion pressure of a mixed gas of compressed air and fuel, a combustion chamber 3 that burns a mixed gas of compressed air and fuel, and a striking cylinder 2 and a combustion chamber 3. A head valve 4 that opens and closes between the head valves 4 and a valve support 5 that supports the head valve 4 are provided.

The striking cylinder 2 is an example of a striking mechanism, and includes a driver 20 for ejecting a fastener supplied from the magazine 14 to the nose portion 12, and a piston 21 provided with the driver 20. The striking cylinder 2 is provided with a cylindrical space in which the piston 21 can slide, and the driver 20 moves along the extending direction of the nose portion 12 by the reciprocating operation of the piston 21.

Further, the striking cylinder 2 includes a cushioning material 22 to which the piston 21 is applied. The cushioning material 22 is made of an elastic member and is provided at the lower part of the striking cylinder 2. In the striking cylinder 2, the moving range of the driver 20 and the piston 21 is restricted by the piston 21 moved by the operation of pushing out the fastener hitting the cushioning material 22.

The combustion chamber 3 is provided in the upper part of the striking cylinder 2 along the axial direction of the driver 20 and the piston 21 which are the axial directions of the striking cylinder 2. The striking cylinder 2 and the combustion chamber 3 are partitioned by a partition portion 50, and the striking cylinder inflow port 51 through which the burned high-temperature and high-pressure air passes is provided in the partition portion 50. The striking cylinder inlet 51 is an example of the striking mechanism inlet, and is configured by providing a circular opening on the shafts of the driver 20 and the piston 21 in the axial direction of the striking cylinder 2.

In the combustion chamber 3, a valve support 5 is provided around the impact cylinder inlet 51, and a ring-shaped space is formed around the valve support 5.

The head valve 4 is an example of a valve body, and is composed of a cylindrical metal member. In the head valve 4, the lower end surface along the axial direction of the cylinder is closed, and a circular and planar valve surface 40 is formed. In the head valve 4, the diameter of the valve surface 40 is larger than that of the impact cylinder inlet 51, and when the valve surface 40 is in contact with the partition portion 50, the impact cylinder inlet 51 is closed.

The head valve 4 includes a first seal portion 41 and a second seal portion 42. The first sealing portion 41 is an example of the sealing portion, and is provided on the outer periphery of the valve surface 40 along the axial direction which is the moving direction of the head valve 4, and the first sealing material 41a is attached. The first sealing material 41a is composed of a metal ring called a piston ring. In the first sealing portion 41, a groove into which the first sealing material 41a is fitted is formed in the circumferential direction, and when the first sealing material 41a is attached, the first sealing material 41a protrudes from the circumferential surface by a predetermined amount. do. In this example, two first sealing materials 41a are attached to the first sealing portion 41 along the axial direction of the head valve 4.

The second sealing portion 42 is an example of a sealing portion, and is provided on the outer periphery of the head valve 4 at a predetermined distance from the first sealing portion 41 along the axial direction of the head valve 4, and is provided as a second sealing material. 42a is attached. The second sealing material 42a is a so-called O-ring made of an elastic body such as rubber. In the second sealing portion 42, a groove into which the second sealing material 42a is fitted is formed in the circumferential direction, and when the second sealing material 42a is attached, the second sealing material 42a protrudes from the circumferential surface by a predetermined amount. do.

In the head valve 4, the first seal portion 41 and the second seal portion 42 project outward from the circumferential surface of the head valve 4, and the second seal portion 42 has a second seal portion 42 with respect to the first seal portion 41. The diameter is large. The surface of the second seal portion 42 facing the first seal portion 41 is an operating surface 43 that is pressed by a high-temperature and high-pressure gas. The working surface 43 is a ring-shaped surface.

The head valve 4 is urged in the direction of the partition portion 50 by the spring 44. The spring 44 is an example of an urging member, and is composed of a coil spring, and the axis of the spring 44 is on the axis of the driver 20 and the piston 21 which are on the axis of the striking cylinder 2, that is, the head valve 4 and the striking cylinder inlet 51. It is provided coaxially. The spring 44 enters the concave portion 45 having an upper opening formed in the head valve 4 along the axial direction which is the moving direction of the head valve 4, so that the head valve 4 and a part of the spring 44 overlap in the axial direction. Will be placed. Such an arrangement is called an overlap arrangement. Further, in order to allow the spring 44 to enter the recess 45 of the head valve 4, the spring 44 has a smaller diameter than the head valve 4, and the spring 44 can have a smaller diameter than the striking cylinder 2.

The force that pushes the head valve 4 by the spring 44 is a force that keeps the valve surface 40 in contact with the partition portion 50 in a state where the high-temperature and high-pressure gas does not act on the operating surface 43.

The head valve 4 is movably supported by the valve support 5.

The valve support 5 is an example of a valve support, and is composed of a cylindrical metal member. In this example, the valve support 5 is integrally provided with a partition portion 50 at the lower portion along the axial direction of the cylinder. When the head valve 4 is inserted into the space inside the cylindrical shape of the valve support 5, the first sealing material 41a of the first sealing portion 41 of the head valve 4 is in sliding contact with the second sealing portion 42. The second sealing material 42a is in sliding contact. The valve support 5 has each seal at a portion where the first sealing material 41a of the first sealing portion 41 of the head valve 4 is in sliding contact and a portion where the second sealing material 42a of the second sealing portion 42 is in sliding contact. The inner diameter is different according to the part.

When the head valve 4 is inserted in the valve support 5, an operating space 52 is formed between the first seal portion 41 and the second seal portion 42 of the head valve 4 and the inner surface of the valve support 5. The working space 52 is an annular space.

The valve support 5 includes a head valve inlet 53 that connects the combustion chamber 3 and the working space 52. The head valve inflow port 53 is configured by providing an opening penetrating the valve support 5 in the vicinity of the first seal portion 41 in a state where the valve surface 40 of the head valve 4 is in contact with the partition portion 50. To. By forming the head valve inflow port 53 on the side surface of the valve support 5, the flow path connecting the combustion chamber 3 and the working space 52 is not complicated, and an increase in inflow resistance can be prevented.

The head valve inflow port 53 is connected to the working space 52 in a state where the valve surface 40 of the head valve 4 is in contact with the partition portion 50, that is, in a state where the impact cylinder inflow port 51 is closed by the head valve 4. ..

On the other hand, when the head valve 4 moves upward due to the action of a high-temperature and high-pressure gas on the operating surface 43 of the head valve 4, the striking cylinder inflow port 51 opens, and the head valve inflow port 53 becomes the striking cylinder inflow port. Connect with 51.

The air passing through the head valve inlet 53 is high-temperature and high-pressure air generated by burning a mixed gas of compressed air and fuel in the combustion chamber 3. Since the high temperature and high pressure gas has a lower viscosity than the air at normal temperature and pressure, the increase in resistance to the gas flow is suppressed even if the opening area of the head valve inlet 53 is small.

The first sealing material 41a is provided on the outer periphery of the first sealing portion 41, and the first sealing material 41a is in contact with the inner surface of the valve support 5. Since the first sealing material 41a is fitted in the groove, the portion exposed to the working space 52 is minimized.

The second sealing material 42a is provided with a second sealing material 42a on the outer periphery thereof, and the second sealing material 42a is in contact with the inner surface of the valve support 5. Since the second sealing material 42a is fitted in the groove, the portion exposed to the working space 52 is minimized.

The valve support 5 includes a cushioning material 54 to which the head valve 4 is applied. The cushioning material 54 is made of an elastic member and is provided on the upper portion of the head valve 4. In the valve support 5, the moving range of the head valve 4 is restricted by the head valve 4 moving due to the action of a high-temperature and high-pressure gas acting on the operating surface 43 of the head valve 4 and hitting the cushioning material 54. The moving range of the head valve 4 is restricted by the cushioning material 54, but when the head valve 4 hits the cushioning material 54, the impact is absorbed by the elastic deformation of the cushioning material 54, so that the height of the head valve inflow port 53 is increased. , It is preferable to keep the stroke of the head valve 4 or less. As a result, when the head valve 4 moves to the position where it hits the cushioning material 54, the head valve 4 can be prevented from being exposed to the head valve inlet 53, and the entire head valve inlet 53 is opened. In this way, the output can be stabilized by keeping the opening amount of the head valve inlet 53 constant.

The upper opening of the combustion chamber 3 is sealed by the head portion 30. The head portion 30 is provided with an ignition device 31. Further, the head portion 30 is provided with a fuel supply port and a compressed air supply port (not shown). Further, by providing the cushioning material 54 so as to be in contact with the head portion 30, the impact applied to the head portion 30 is buffered, the durability of the parts is improved, the bolts that attach the head portion 30 to the combustion chamber 3 are prevented from loosening, and electrical noise is generated. Effects such as reduction of noise can be obtained.

The nailing machine 1A includes a driver 20 of the striking cylinder 2 and a blowback chamber 6 for storing gas for returning the piston 21. The blowback chamber 6 is provided around the striking cylinder 2 and is connected to the inside of the striking cylinder 2 by an inflow / discharge port 60 provided in the vicinity of the cushioning material 22.

The nailing machine 1A includes an exhaust valve 7 attached to the striking cylinder 2 so that the gas in the striking cylinder 2 and the combustion chamber 3 is exhausted and a part thereof is exposed, and a long hole portion 78 formed in the exhaust valve 7. To prepare for. The elongated hole portion 78 corresponds to an example of an engaging portion.

As shown in FIGS. 3A, 3B and 4, the exhaust valve 7 opens and closes the exhaust piston 71 pushed by the gas flowing into the blowback chamber 6 and the striking cylinder exhaust port 23 formed in the striking cylinder 2. The exhaust valve 72 of No. 1, the second exhaust valve 73 for opening and closing the combustion chamber exhaust port 32 formed in the combustion chamber 3, the exhaust piston 71, the first exhaust valve 72, and the second exhaust valve 73 were connected. A valve rod 74 is provided.

Further, the exhaust valve 7 includes an exhaust cylinder 75 connected to the blowback chamber 6, and an exhaust flow path forming cylinder 76 connected to the striking cylinder exhaust port 23 and the combustion chamber exhaust port 32. The exhaust cylinder 75 is provided with a cylindrical space in which the exhaust piston 71 can slide, and the exhaust valve 7 moves along the extending direction of the valve rod 74 by the reciprocating operation of the exhaust piston 71. The exhaust flow path forming cylinder 76 is provided with a cylindrical space in which the first exhaust valve 72 and the second exhaust valve 73 can slide, and the striking cylinder exhaust port 23 and the combustion chamber exhaust port 32 are provided with an exhaust flow path. It is provided so as to penetrate the forming cylinder 76. Further, the exhaust valve 7 includes a cushioning material 77 to which the exhaust piston 71 is applied. The cushioning material 77 is composed of an elastic member. The range of movement of the exhaust valve 7 is restricted by the exhaust piston 71 hitting the cushioning material 77.

When the first exhaust valve 72 opens the striking cylinder exhaust port 23, the second exhaust valve 73 opens the combustion chamber exhaust port 32 in conjunction with this. On the other hand, when the first exhaust valve 72 closes the striking cylinder exhaust port 23, the second exhaust valve 73 closes the combustion chamber exhaust port 32 in conjunction with this.

The slotted hole 78 is a relief for operating the exhaust valve 7 independently of the contact member 8 when the exhaust valve 7 receives a predetermined load from the gas flowing from the striking cylinder 2 based on the operation of the piston 21. Functions as a department. The slotted hole 78 penetrates the exhaust valve 7 in the front-rear direction. The length of the slotted hole 78 in the longitudinal direction is formed longer than the length of the front end portion 81a of the link 81 to be described later inserted in the slotted hole 78 in the vertical direction (width direction). As a result, the front end portion 81a of the link 81 can move along the axial direction of the exhaust valve 7 in the slotted hole 78, and the shaft of the exhaust valve 7 is applied when a load equal to or more than a predetermined load is applied to the exhaust valve 7. It is possible to regulate the movement in the direction within a predetermined range.

Below the elongated hole 78 of the exhaust valve 7, a spring 79 that urges the closed position to close the exhaust valve 7 is attached. The spring 79 is, for example, a compression spring. The upper end portion 79a of the spring 79 is supported by the regulation portion 2a fixed to the striking cylinder 2, and the lower end portion 79b of the spring 79 is supported by the spring retainer 74a attached to the valve rod 74 of the exhaust valve 7. As a result, the exhaust valve 7 is urged by the spring 79 in the direction of closing the exhaust valve 7.

The nailing machine 1A includes a contact member 8 and a link mechanism 800. The contact member 8 is provided so as to be movable along the extending direction of the nose portion 12, and is urged by the springs 80a and 80b in a direction protruding from the nose portion 12 via the link mechanism 800. Further, the link mechanism 800 is urged by the springs 80a and 80b in the direction of opening the exhaust valve 7 via the elongated hole portion 78. The contact member 8 and the exhaust valve 7 are connected via the link mechanism 800. The exhaust valve 7 and the link mechanism 800 are connected via an elongated hole 78 formed in the valve rod 74, and the exhaust valve 7 operates in conjunction with the movement of the contact member 8 and is separated from the contact member 8. Then, the exhaust valve 7 is operated by the gas flowing into the blowback chamber 6.

The link mechanism 800 has a pair of links 81 and 82 and a connecting portion 83 connecting the links 81 and 82. The link mechanism 800 corresponds to an example of the engaging portion.

The link 81 is composed of an elongated plate-shaped member. The substantially central portion of the link 81 is rotatably attached to a shaft 81d provided on the right side surface portion of the striking cylinder 2. The front end portion 81a of the link 81 is slidably inserted into the elongated hole portion 78 of the exhaust valve 7 along the axial direction (vertical direction) of the exhaust valve 7. One end of a spring 80a made of a tension spring is attached to the rear end 81b of the link 81. The other end of the spring 80a is attached to the attachment portion 87 provided on the right side surface portion of the cylinder 2. The rear end portion 81b of the link 81 is urged to the nose portion 12 side (lower side) by the spring 80a.

The link 82 is arranged so as to face the link 81 with the striking cylinder 2 interposed therebetween, and is rotatably attached to a mounting portion provided on the left side surface portion of the striking cylinder 2 (not shown). One end of a spring 80b made of a tension spring is attached to the rear end 82b of the link 82. The other end of the spring 80b is attached to the attachment portion 88 provided on the left side surface portion of the impact cylinder 2. The rear end portion 82b of the link 82 is urged to the nose portion 12 side (lower side) by the spring 80b.

The connecting portion 83 connects the rear end portion 81b of the link 81 and the rear end portion 82b of the link 82. At the substantially central portion of the connecting portion 83 in the longitudinal direction (left-right direction), a contact portion 83a is formed so as to project to the rear side (handle portion 11 side) and to contact the upper end portion of the contact member 8.

<Operation example of the nailing machine 1A of the present embodiment>
Next, the operation of the nailing machine 1A of the present embodiment will be described. 5A is a cross-sectional view showing an operation example when the contact member 8 is on and the exhaust valve 7 is in the closed position in the nailing machine 1A of the present embodiment, and FIG. 5B is shown in line BB of FIG. 5A. It is a cross-sectional view along. To. FIG. 6A is a cross-sectional view showing an operation example when the contact member 8 is on and the exhaust valve 7 is in the open position in the nailing machine 1A of the present embodiment, and FIG. 6B is taken along the line CC of FIG. 6A. It is a cross-sectional view along.

As shown in FIGS. 3A and 3B, in the initial state, the operation trigger 16 is not pulled, the contact member 8 is not pushed by the material to be driven, and the springs 80a and 80b urge the contact member 8. It is in the initial position protruding from the nose portion 12.

In the state where the contact member 8 is in the initial position, the exhaust valve 7 is in a state where the first exhaust valve 72 opens the striking cylinder exhaust port 23 and the second exhaust valve 73 opens the combustion chamber exhaust port 32. As a result, the striking cylinder 2 and the combustion chamber 3 are open to the atmosphere.

Further, the head valve 4 is in a state where the valve surface 40 is pressed by the spring 44 and is in contact with the partition portion 50, that is, the impact cylinder inflow port 51 is closed by the head valve 4. In this state, the head valve inlet 53 is connected to the working space 52.

As shown in FIGS. 4, 5A and 5B, when the contact member 8 is pressed against the material to be driven, the contact member 8 moves upward relative to the nose portion 12, and the upper end portion of the contact member 8 is formed. 8a pushes up the connecting portion 83 (contact portion 83a) upward against the elastic force of the springs 80a and 80b. Along with this, the rear end side of the link 81 connected to the connecting portion 83 moves upward, so that the tip end side of the link 81 rotates downward with the shaft 81d as a fulcrum. When the link 81 rotates, the compressed spring 79 expands with the restricting portion 2a as the starting point, so that the exhaust valve 7 attached to the lower end portion 79b of the spring 79 also moves downward. As a result, the movement of the contact member 8 is transmitted to the exhaust valve 7 by the link 81, and in the exhaust valve 7, as shown in FIG. 5B, the first exhaust valve 72 closes the striking cylinder exhaust port 23, and the second exhaust. The valve 73 is in a state where the combustion chamber exhaust port 32 is closed. That is, the striking cylinder 2 and the combustion chamber 3 are sealed.

In this way, the link mechanism 800 reverses the pressing direction D1 of the contact portion 8 against the material to be driven and the operating direction D2 of the exhaust valve 7 that operates in association with the pressing operation of the contact portion 8 ( See FIG. 3A). Further, in the present embodiment, the amount of downward movement of the front end portion 81a of the link 81 of the link mechanism 800 in the elongated hole portion 78 when the contact portion 8 is pressed against the material to be driven is the exhaust valve 7. It is larger than the downward movement amount (stroke) of (see FIGS. 3A and 5A).

Subsequently, as shown in FIG. 2A, an air valve and a fuel valve (not shown) are opened in conjunction with the operation of the contact member 8 and the operation trigger 16, and the vaporized fuel and compressed air are supplied to the combustion chamber 3. For example, when the contact member 8 is pressed against the material to be driven, a fuel valve (not shown) is opened, and when the operation trigger 16 is operated, an air valve (not shown) is opened. When the contact member 8 is pressed against the material to be driven and the operation trigger 16 is operated, the air valve and the fuel valve (not shown) may be opened at predetermined timings. Further, when the contact member 8 is pressed against the material to be driven, the air valve and the fuel valve (not shown) may be opened at predetermined timings.

When compressed air is supplied to the combustion chamber 3, the pressure in the combustion chamber 3 rises. However, when the pressure in the combustion chamber 3 rises due to compressed air, the head valve 4 is pressed by the spring 44 to keep the valve surface 40 in contact with the partition portion 50, and the impact cylinder inflow port 51 is closed by the head valve 4. Be done. Therefore, even if the pressure inside the combustion chamber 3 rises due to the supply of compressed air, the pressure rise does not occur in the striking cylinder 2, and the piston 21 does not operate.

After the contact member 8 is pressed against the material to be driven and the operation trigger 16 is operated to open an air valve and a fuel valve (not shown), when the ignition device 31 is operated at a predetermined timing, compression in the combustion chamber 3 is performed. A mixed gas of air and fuel burns. When the mixed gas burns in the combustion chamber 3, the pressure in the combustion chamber 3 rises, and the high-temperature and high-pressure gas flows into the working space 52 from the head valve inflow port 53 of the valve support 5.

As shown in FIG. 2B, when the pressure in the working space 52 rises, a high-temperature and high-pressure gas acts on the working surface 43 of the head valve 4, so that the head valve 4 moves upward while compressing the spring 44. Here, when the pressure in the working space 52 rises, the pressure is also applied to the surface of the first seal portion 41 facing the working space 52. However, since the working surface 43 has a larger area, the head valve 4 rises while compressing the spring 44.

When the head valve 4 moves upward, the striking cylinder inlet 51 opens, and the head valve inlet 53 is connected to the striking cylinder inlet 51. As a result, the high-temperature and high-pressure gas flows from the combustion chamber 3 through the striking cylinder inlet 51 into the striking cylinder 2, and the pressure of the striking cylinder 2 rises.

When the pressure of the striking cylinder 2 rises, the piston 21 is pushed, the piston 21 and the driver 20 move in the direction of launching the fastener, and the fastener driving operation is performed. When the piston 21 and the driver 20 move in the direction of launching the fastener, the lower gas (air) in the striking cylinder 2 partitioned by the piston 21 flows into the blowback chamber 6 from the inflow / discharge port 60. Further, since the piston 21 passes through the inflow / discharge port 60 while compressing and deforming the cushioning material 22, a part of the high-temperature and high-pressure gas that drives the piston 21 flows into the blowback chamber 6.

As shown in FIGS. 6A and 6B, when the gas (air) in the striking cylinder 2 flows into the blowback chamber 6 and the pressure in the blowback chamber 6 rises, the exhaust piston 71 of the exhaust valve 7 moves upward. Be urged. Along with this, the exhaust valve 7 moves upward against the elastic force of the spring 79 and moves to a position where it collides with the cushioning material 77. Since the movement amount of the exhaust valve 7 is regulated by the cushioning material 77, the durability of the exhaust valve 7 is improved.

In the present embodiment, the exhaust valve 7 is connected to the link 81 and the contact member 8 via the elongated hole 78 formed in the valve rod 74, and is therefore separated from the movement of the contact member 8. That is, the exhaust valve 7 can operate independently without being interlocked with the contact member 8 when the contact member 8 is on. As a result, when the exhaust piston 71 of the exhaust valve 7 is pushed, as shown in FIG. 6B, the first exhaust valve 72 opens the striking cylinder exhaust port 23, and the second exhaust valve 73 opens the combustion chamber exhaust port 32. The exhaust valve 7 moves to the open state.

Therefore, the striking cylinder 2 and the combustion chamber 3 are opened to the atmosphere, and the gas in the combustion chamber 3 is exhausted to the outside from the combustion chamber exhaust port 32. Further, as the pressure in the combustion chamber 3 decreases, the head valve 4 is pressed by the spring 44 and moves to a position where the valve surface 40 is in contact with the partition portion 50, and the impact cylinder inflow port 51 is the head valve 4. Closed.

Further, when the piston 21 and the driver 20 move in the direction of launching the fastener and the piston 21 moves to the bottom dead center and hits the cushioning material 22, the piston 21 and the driver 20 tend to move upward due to the elasticity of the cushioning material 22. .. When the piston 21 passes through the inflow / discharge port 60 and moves to the upper side of the inflow / discharge port 60, the gas in the blowback chamber 6 where the pressure is increasing flows into the striking cylinder 2, and when the piston 21 is pushed, The upper gas in the striking cylinder 2 partitioned by the piston 21 is exhausted to the outside from the striking cylinder exhaust port 23, and the piston 21 and the driver 20 return to the top dead point.

As shown in FIGS. 3A, 3B and 4, when the contact member 8 is separated from the material to be driven, the upper end portion 8a of the contact member 8 is connected to the connecting portion 83 (contact portion 83a) by the elastic force of the springs 80a and 80b. The contact member 8 is urged downward via the nose portion 12 and moves downward relative to the nose portion 12. By moving the rear end side of the link 81 connected to the connecting portion 83 downward, the front end side of the link 81 rotates upward with the shaft 81d as a fulcrum. When the link 81 rotates, the front end portion 81a of the link 81 pushes the upper end opening edge of the elongated hole portion 78 upward, and the spring 79 in the expanded state is compressed, so that the exhaust valve 7 moves upward. As a result, as shown in FIG. 3B, the state in which the first exhaust valve 72 opens the striking cylinder exhaust port 23 and the second exhaust valve 73 opens the combustion chamber exhaust port 32 is maintained.

As described above, according to the present embodiment, the following actions and effects can be obtained. In the past, it has been proposed to adopt a configuration that opens and closes the exhaust valve using blowback pressure so that the start of exhaust is not delayed, but it is necessary to link the closing operation of the exhaust valve with the pressing operation of the contact part. there were. Therefore, there is a problem that the contact portion is returned by opening the exhaust valve due to the increase in the blowback pressure, and the workability at the time of driving operation is deteriorated.

On the other hand, according to the present embodiment, as the pressure in the blowback chamber 6 rises due to the drive of the piston 21, the first exhaust valve 72 is exhausted to the striking cylinder through the elongated hole portion 78 of the exhaust valve 7. The second exhaust valve 73 can be moved to the open position of the combustion chamber exhaust port 32 by moving to the open position of the port 23. As a result, the exhaust valve 7 can be operated independently of the contact member 8, and the exhaust operation can be performed immediately after the fastener driving operation is completed without operating the contact member 8. As a result, it is possible to prevent a decrease in workability during the driving operation, and it is possible to prevent dew condensation and the like in the combustion chamber 3 and the striking cylinder 2, so that the driving operation can be stabilized.

Further, according to the present embodiment, since the structure in which the exhaust valve 7 is attached to the striking cylinder 2 so that a part of the exhaust valve 7 is exposed is adopted, the engagement portion (long hole portion 78) with the link 81 and the spring 79 are adopted. Since it is not necessary to secure the sealing property around the surface, the structure of the nailing machine 1A can be simplified.

The technical scope of the present invention is not limited to the above-described embodiment, and includes various modifications to the above-mentioned embodiment without departing from the spirit of the present invention.

For example, in the above-described embodiment, the configuration using the link mechanism 800 is adopted as the engaging means for engaging the contact member 8 and the exhaust valve 7, but the present invention is not limited to this. Instead of using the link mechanism 800, the contact member 8 and the exhaust valve 7 are connected by using a member such as a spring to drive the exhaust valve 7 in conjunction with the operation of the contact member 8, or the exhaust valve 7 is driven by the piston 21. It may be driven in conjunction with the operation of.

Further, in the above-described embodiment, an example in which the cushioning material 77 is used as a member for absorbing the impact when the exhaust valve 7 moves upward has been described, but the present invention is not limited thereto. For example, a compression spring may be used instead of the cushioning material 77. When adopting this configuration, the spring 79 may be omitted, or a configuration using both springs may be adopted. Further, in the present embodiment, air is used as an oxidizing agent, and the configuration is such that the operation is performed by a mixed gas of compressed air and fuel. However, if oxygen required for fuel combustion is contained, the composition is not limited to compressed air. Oxidizing agent may be used. For example, oxygen, ozone, nitric oxide or the like may be used instead of air.

1A Nailer 2 Strike cylinder (cylinder)
3 Combustion chamber 6 Blowback chamber 7 Exhaust valve 8 Contact part 10 Main body part 20 Driver (battering mechanism)
21 Piston (battering mechanism)
23 Impact cylinder exhaust port 32 Combustion chamber exhaust port 71 Exhaust piston 72 First exhaust valve 73 Second exhaust valve 74 Valve rod 75 Exhaust cylinder 76 Exhaust flow path forming cylinder 77 Cushioning material 78 Long hole part (engagement part)
79 Spring (Bending member)
81 Link 800 Link mechanism

Claims (7)

A combustion chamber where a mixed gas of compressed oxidizer and fuel burns,
A cylinder accommodating a striking mechanism operated by the combustion pressure generated by combustion of the mixed gas in the combustion chamber, and
An exhaust valve that opens the combustion chamber and the inside of the cylinder to the outside and shuts off the inside and the outside of the combustion chamber and the cylinder.
The exhaust valve is operated based on the pressing operation against the material to be driven to shut off the combustion chamber and the cylinder from the outside, and a contact portion for making the striking mechanism operable is provided .
The exhaust valve is configured to operate independently of the contact portion when a predetermined load is applied by the operation of the striking mechanism.
Driving tool. The exhaust valve is provided with an urging member that urges the combustion chamber and the inside of the cylinder to the outside of the driving tool.
The driving tool according to claim 1. The driving according to claim 1 or 2, wherein the exhaust valve is urged by a gas flowing from the inside of the cylinder by the operation of the striking mechanism to open the combustion chamber and the inside of the cylinder to the outside of the driving tool. tool. A link mechanism provided between the contact portion and the exhaust valve and having a contact portion with which the contact portion abuts is provided at one end thereof.
The driving tool according to any one of claims 1 to 3 , wherein the exhaust valve has an engaging portion in which the other end of the link mechanism is movably engaged. The driving tool according to claim 4 , wherein the amount of movement of the other end of the link mechanism engaged with the engaging portion by pressing the contact portion against the driven material is larger than the stroke of the exhaust valve. .. The driving tool according to claim 4 or 5 , wherein the link mechanism reverses the pressing direction of the contact portion against the material to be driven and the operating direction of the exhaust valve . The driving tool according to any one of claims 1 to 6, wherein the exhaust valve is attached to the cylinder so that a part of the valve is exposed .

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