Driving tool

A driving tool includes a striking mechanism configured to be actuated by a combustion pressure of a mixed gas of compressed air and fuel, a combustion chamber in which the mixed gas of compressed air and fuel is to be combusted, a valve member configured to open and close communication between the striking mechanism and the combustion chamber, and a valve support member configured to support the valve member. The valve member has a seal part provided on an outer peripheral surface along a moving direction of the valve member.

CROSS-REFERENCE TO RELATED APPLICATION

TECHNICAL FIELD

The present disclosure relates to a driving tool configured to combust a mixed gas of air and fuel and to be driven by a combustion pressure.

BACKGROUND

A driving tool referred to as a nailing machine configured to strike a fastener such as a nail by actuating a piston with a striking cylinder by using a compressed air as a power source and driving a driver joined to the piston has been known. In the driving tool, a valve referred to as a head valve is configured so that the compressed air is to be supplied from a side of the striking cylinder.

Also, a driving tool referred to as a nailing machine configured to strike a fastener such as a nail by combusting a mixed gas of air and fuel and actuating a striking cylinder by a combustion pressure has been known. In the gas combustion type driving tool, the mixed gas of which a pressure has been increased in advance is combusted to further increase the combustion pressure. However, since the mixed gas of which a pressure has been increased is generated, when the compressed air is supplied to a combustion chamber, the striking cylinder is actuated by a pressure of the compressed air before the mixed gas is combusted.

Therefore, a driving tool including a valve configured to openably/closably partition a combustion chamber in which a mixed gas of compressed air and fuel is to be combusted and a striking cylinder has been suggested (for example, refer to Patent Document 1).

In the related art, the same configuration as the driving tool in which the compressed air is used as a power source is used for the valve configured to openably/closably partition the combustion chamber and the striking cylinder, and the high temperature and high pressure combusted gas is supplied to the valve from a side of the striking cylinder.

In the above configuration, a seal material is provided on an end face of the valve in a moving direction. However, in a state where the valve is opened, the seal material is exposed to a flow path of the gas. Since the gas which is obtained as a result of the combustion of the mixed gas of compressed air and fuel is at the high temperature and high pressure, when the seal material is exposed to the flow path of the gas, the durability of the seal material is deteriorated due to an influence of heat. Also, a spring configured to urge the valve in a closing direction is provided. However, in the configuration where the high temperature and high pressure combusted gas is supplied from a side of the striking cylinder, a diameter of the spring increases, which in turn increases a size of a main body.

SUMMARY

The present disclosure has been made in view of the above situations, and an object thereof is to provide a driving tool capable of improving durability of a seal part and suppressing a size of a main body from increasing.

One aspect of the present disclosure is a driving tool comprising: a striking mechanism configured to be actuated by a combustion pressure of a mixed gas of compressed air and fuel; a combustion chamber in which the mixed gas of compressed air and fuel is to be combusted; a valve member configured to open and close communication between the striking mechanism and the combustion chamber; and a valve support member configured to support the valve member, wherein the valve member has a seal part provided on an outer peripheral surface along a moving direction of the valve member.

According to the present disclosure, the seal part is provided on the outer periphery of the valve member configured to open and close communication between the striking mechanism and the combustion chamber, so that the seal part is suppressed from being exposed to a gas obtained as a result of combustion of a mixed gas of compressed air and fuel.

One aspect of the present disclosure is a driving tool comprising: a striking mechanism configured to be actuated by a combustion pressure of a mixed gas of compressed air and fuel; a combustion chamber in which the mixed gas of compressed air and fuel is to be combusted; a valve member configured to open and close communication between the striking mechanism and the combustion chamber; and a valve support member configured to support the valve member, wherein an urging member configured to urge the valve member is provided on an axis of the striking mechanism.

According to the present disclosure, the urging member configured to urge the valve member is provided on the axis of the striking mechanism, so that the urging member can be made small.

According to the present disclosure, the mixed gas of compressed air and fuel is combusted, the striking mechanism is actuated by the combustion pressure, and the durability of the seal part can be improved. Also, it is possible to make the urging member small, thereby suppressing a size of the main body from increasing.

DETAILED DESCRIPTION

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

<Configuration Example of Nailing Machine of Embodiment>

FIG. 1is an overall view depicting an example of a nailing machine of an embodiment, andFIGS. 2 and 3are views of main parts depicting an example of the nailing machine of the embodiment and an operation example.

A nailing machine1A of the embodiment includes a main body part10and a handle part11extending from the main body part10and configured to be gripped by a hand. The nailing machine1A includes a nose part12provided at one side of the main body part10and configured to strike out a fastener therefrom. In below descriptions, considering a using aspect of the nailing machine1A, the side at which the nose part12is provided is referred to as ‘lower side’.

The nailing machine1A includes a tank mounting part13, to which a fuel tank (not shown) having fuel filled therein is detachably mounted and which is provided substantially in parallel with the handle part11below the handle part. Also, the nailing machine1A includes a magazine14configured to share fasteners with the nose part12and provided below the tank mounting part13. Also, the nailing machine1A includes an air plug15to which an air hose, to which compressed air that is compressed oxidant is to be supplied from a supply source such as an air compressor, is connected and which is provided to the tank mounting part13, in the embodiment.

Also, the nailing machine1A includes an operation trigger16configured to actuate the nailing machine1A and provided to the handle part11. A battery17which is a power supply of the nailing machine1A is mounted to a battery mounting part18. The battery mounting part is provided to the handle part11.

The nailing machine1A includes a striking cylinder2configured to be actuated by a combustion pressure of a mixed gas of compressed air and fuel, a combustion chamber3in which the mixed gas of compressed air and fuel is to be combusted, a head valve4configured to open and close communication between the striking cylinder2and the combustion chamber3, and a valve support member5configured to support the head valve4.

The striking cylinder2is an example of the striking mechanism, and includes a driver20configured to strike out a fastener supplied from the magazine14to the nose part12and a piston21to which the driver20is provided. The striking cylinder2has a cylindrical space in which the piston21can be slid, and is configured so that the driver20is to move along the extension direction of the nose part12by a reciprocal operation of the piston21.

The striking cylinder2has a piston position restraint part2aprovided at a peripheral edge of an upper end and formed to have a tapered shape of which a diameter increases upward. When the piston21is moved upward, a piston ring21aprovided on an outer peripheral surface of the piston21is engaged to the piston position restraint part2a, so that a top dead point position of the piston21is defined. In the meantime, the engagement of the piston21with the piston position restraint part2ais released by a force of pushing the piston21by a combustion pressure, so that the piston21can move by the combustion pressure.

Also, the striking cylinder2includes a buffer material22with which the piston21is to collide. The buffer material22is configured by an elastic member and is provided at a lower part of the striking cylinder2. In the striking cylinder2, the piston21having moved by an operation of striking out a fastener collides with the buffer material22, so that movement ranges of the driver20and the piston21are restrained.

The combustion chamber3is provided above the striking cylinder2along axial directions of the driver20and the piston21, which are an axial direction of the striking cylinder2. The striking cylinder2and the combustion chamber3are partitioned by a partitioning part50, and the partitioning part50is provided with a striking cylinder inlet51through which high temperature and high pressure combusted air is to pass. The striking cylinder inlet51is an example of the striking mechanism inlet, and is configured by forming a circular opening on axes of the driver20and the piston21, which are the axial direction of the striking cylinder2.

The combustion chamber3has the valve support member5provided around the striking cylinder inlet51, and a ring-shaped space formed around the valve support member5. Therefore, the combustion chamber3is arranged radially outside of the valve support member5and the head valve4.

The head valve4is an example of the valve member, and is configured by a cylindrical metal member. As shown inFIGS. 6 and 7, the head valve4has a circular planar valve surface40of which a lower end face in an axial direction of the cylinder is closed. The head valve4has a configuration where a diameter of the valve surface40is larger than the striking cylinder inlet51. The striking cylinder inlet51is closed in a state where the valve surface40is in contact with the partitioning part50.

The head valve4has a first seal part41and a second seal part42. The first seal part41is an example of the seal part, is provided on an outer periphery of the valve surface40in the axial direction, which is a moving direction of the head valve4, and is attached with a first seal material41a. The first seal material41ais configured by a metal ring referred to as a piston ring. The first seal part41has a circumferential groove in which the first seal material41ais fitted. When the first seal material41ais attached to the first seal part, the first seal material41aprotrudes from a circumferential surface by a predetermined amount. In the case of the first seal part41of the embodiment, the two first seal materials41aare attached along the axial direction of the head valve4.

The second seal part42is an example of the seal part, is provided on the outer periphery of the head valve4with being spaced from the first seal part41by a predetermined distance along the axial direction of the head valve4, and is attached with a second seal material42a. The second seal material42ais a so-called O-ring made of an elastic body such as rubber. The second seal part42has a circumferential groove in which the second seal material42ais fitted. When the second seal material42ais attached to the second seal part, the second seal material42aprotrudes from a circumferential surface by a predetermined amount.

The head valve4has a configuration where the first seal part41and the second seal part42protrude outward from the circumferential surface of the head valve4and a diameter of the second seal part42is larger than a diameter of the first seal part41. The second seal part42has an actuation surface43that is a surface facing the first seal part41and is to be pushed by a high temperature and high pressure gas. The actuation surface43is a ring-shaped surface.

The head valve4is configured to be urged in a direction of the partitioning part50by a spring44. The spring44is an example of the urging member, and is configured by a coil spring. An axis of the spring44is provided on the axes of the driver20and the piston21, which are on the axis of the striking cylinder2, i.e., is provided coaxially with the head valve4and the striking cylinder inlet51. The spring44is introduced into a concave part45having an open upper and formed in the head valve4along the axial direction, which is a moving direction of the head valve4, so that the head valve4and a part of the spring44are arranged so as to overlap each other. This arrangement is referred to as ‘overlap arrangement’. Also, in order for the spring44to be introduced into the concave part45of the head valve4, a diameter of the spring44is made to be smaller than the head valve4and the striking cylinder2.

A force of pushing the head valve4by the spring44is a force of keeping a contact state of the valve surface40with the partitioning part50in a state where the high temperature and high pressure gas is not applied to the actuation surface43.

The head valve4is supported to be moveable by the valve support member5.

The valve support member5is an example of the valve support member and is configured by a cylindrical metal member. As shown inFIGS. 6 and 7, in the embodiment, the valve support member5has the partitioning part50integrally provided at an axial lower part of the cylinder. When the head valve4is put in the cylindrical inner space, the first seal material41aof the first seal part41and the second seal material42aof the second seal part42of the head valve4are sliding contacted to the valve support member5. The valve support member5has different inner diameters at parts to which the first seal material41aof the first seal part41and the second seal material42aof the second seal part42of the head valve4are sliding contacted, in conformity to the respective seal parts.

When the head valve4is put in the valve support member5, an actuation space52is formed between the first seal part41and second seal part42of the head valve4and an inner surface of the valve support member5. The actuation space52is an annular space.

The valve support member5has a head valve inlet (valve member inlet)53for connecting the combustion chamber3and the actuation space52. The head valve inlet53is configured by providing an opening penetrating the valve support member5in the vicinity of the first seal part41in a state where the valve surface40of the head valve4is in contact with the partitioning part50. The head valve inlet53is formed on a side surface of the valve support member5, so that a flow path connecting the combustion chamber3and the actuation space52becomes simple and an increase in inflow resistance can be prevented.

As shown inFIG. 6, the head valve inlet53is coupled to the actuation space52in the state where the valve surface40of the head valve4is in contact with the partitioning part50, i.e., in the state where the striking cylinder inlet51is closed by the head valve4.

In contrast, when the high temperature and high pressure gas is applied to the actuation surface43of the head valve4and the head valve4is thus moved upward, as shown inFIG. 7, the striking cylinder inlet51is opened and the head valve inlet53is coupled to the striking cylinder inlet51.

The air to pass through the head valve inlet53is the high temperature and high pressure air generated by combusting the mixed gas of compressed air and fuel in the combustion chamber3. Since the high temperature and high pressure gas has lower viscosity than the ordinary temperature and pressure air, the increase in resistance against the gas flow is suppressed even though an opening area of the head valve inlet53is small.

The first seal part41has the first seal material41aprovided on the outer periphery thereof, and the first seal material41ais in contact with the inner surface of the valve support member5. Since the first seal material41ais fitted in the groove, a part to be exposed to the actuation space52is suppressed to the minimum.

The second seal part42has the second seal material42aprovided on the outer periphery thereof, and the second seal material42ais in contact with the inner surface of the valve support member5. Since the second seal material42ais fitted in the groove, a part to be exposed to the actuation space52is suppressed to the minimum.

The valve support member5has a buffer material54with which the head valve4is to collide. The buffer material54is configured by an elastic member and is provided at an upper part of the head valve4. The head valve4having moved due to the high temperature and high pressure gas applied to the actuation surface43of the head valve4collides with the buffer material54of the valve support member5, so that a movement range of the head valve4is restrained. In the meantime, although the movement range of the head valve4is restrained by the buffer material54, when the head valve4collides with the buffer material54, a shock is absorbed by elastic deformation of the buffer material54. Therefore, a height of the head valve inlet53is preferably set to be equal to or smaller than a stroke of the head valve4. Thereby, when the head valve4moves up to a position at which it is to collide with the buffer material54, the head valve4is not exposed to the head valve inlet53and the head valve inlet53is entirely opened. In this way, an opening amount of the head valve inlet53is made constant, so that it is possible to stabilize an output.

The upper opening of the combustion chamber3is sealed by a head part30. The head part30is provided with an ignition device31. Also, the head part30is provided with a fuel supply port and a compressed air supply port (not shown). Also, the buffer material54is provided to be in contact with the head part30, so that the shock to be applied to the head part30is buffered, durability of a component is improved, a bolt for fastening the head part30to the combustion chamber3is prevented from being unfastened, and an electric noise is reduced.

FIG. 8is a perspective view depicting a first embodiment of the head part,FIG. 9is a top view of the head part of the first embodiment and the combustion chamber, andFIG. 10is a sectional view of the head part of the first embodiment and the combustion chamber. Also,FIG. 11is a sectional view taken along a line A-A ofFIG. 9,FIG. 12is a sectional view taken along a line B-B ofFIG. 9, andFIG. 13is a sectional view taken along a line C-C ofFIG. 9.

A head part30A, which is the first embodiment of the head part30, is provided with an ignition device31. Also, the head part30A is provided with a fuel supply port30Fe to which the fuel is to be supplied and an air supply port30Ea to which the compressed air is to be supplied. The head part30A has the fuel supply port30Fe and the air supply port30Ea provided in parallel with each other.

The fuel supply port30Fe is configured by providing an opening to penetrate a top surface30U, which is an inner wall surface of the head part30A facing the combustion chamber3, and is attached with a fuel pipe conduit connection member30Fp to which a fuel pipe conduit30Fi shown inFIG. 2is to be connected. Also, the air supply port30Ea is an example of the oxidant supply port, is configured by providing an opening to penetrate the top surface30U of the head part30A, and is attached with an air pipe conduit connection member30Ep to which an air pipe conduit30Ei shown inFIGS. 2 and 3is to be connected.

Also, the head part30A has a fuel-side lead valve30FB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the fuel supply port30Fe and an air-side lead valve30EB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the air supply port30Ea. Also, the head part30A has an air stirring part33configured to change an outflow direction of the compressed air to be supplied from the air supply port30Ea.

The fuel-side lead valve30FB is an example of the check valve, is configured by an elastic metal plate, and has a valve part34FB configured to open/close the fuel supply port30Fe, a fixed part35FB to be fixed to the head part30A, and an elastic part36FB configured to couple the valve part34FB and the fixed part35FB.

The fuel-side lead valve30FB has such a shape that the valve part34FB is to cover the entire fuel supply port30Fe. Also, the fixed part35FB of the fuel-side lead valve30FB, which is distant from the fuel supply port30Fe at which the valve part34FB covers the fuel supply port30Fe, is fixed to the top surface30U of the head part30A by a screw37FB.

The head part30A is formed on the top surface30U of a peripheral edge of the fuel supply port30Fe with a seal part30Fs that is in contact with the valve part34FB of the fuel-side lead valve30FB.

Thereby, when the fixed part35FB is fixed to the top surface30U of the head part30A, the valve part34FB of the fuel-side lead valve30FB is pressed to the seal part30Fs by the elasticity of the elastic part36FB and the fuel supply port30Fe is thus closed.

Also, the fuel-side lead valve30FB is moved in a direction in which the valve part34FB is connected/separated to/from the seal part30Fs as the elastic part36FB is elastically deformed, thereby opening/closing the fuel supply port30Fe.

The fuel-side lead valve30FB has an urging part38FB configured to urge the valve part34FB in a direction of the seal part30Fs. As shown inFIG. 13, the urging part38FB is configured by providing a bent part having a predetermined shape to the elastic part36FB, and is configured to suppress the valve part34B from floating from the seal part30Fs in a state where the fuel supply port30Fe is closed with the valve part34B by the elasticity of the elastic part36B.

The air-side lead valve30EB is an example of the check valve, is configured by an elastic metal plate, and has a valve part34EB configured to open/close the air supply port30Ea, a fixed part35EB to be fixed to the head part30A, and an elastic part36EB configured to couple the valve part34EB and the fixed part35EB.

The air-side lead valve30EB has the fixed part35EB provided at a side distant from the fuel supply port30Fe with respect to the arrangement of the fuel supply port30Fe and the air supply port30Ea, and the valve part34EB configured to open/close the air supply port30Ea and provided between the fixed part35EB and fuel supply port30Fe.

The air-side lead valve30EB has such a shape that the valve part34EB is to cover the entire air supply port30Ea. Also, the fixed part35EB of the air-side lead valve30EB, which is distant from the air supply port30Ea at which the valve part34EB covers the air supply port30Ea, is fixed to the top surface30U of the head part30A by a screw37EB, together with the air stirring part33.

The head part30A is formed on the top surface30U of a peripheral edge of the air supply port30Ea with a seal part30Es that is in contact with the valve part34EB of the air-side lead valve30EB.

Thereby, when the fixed part35EB is fixed to the top surface30U of the head part30A, the valve part34EB of the air-side lead valve30EB is pressed to the seal part30Es by the elasticity of the elastic part36EB and the air supply port30Ea is thus closed.

Also, the air-side lead valve30EB is moved in a direction in which the valve part34EB is connected/separated to/from the seal part30Es as the elastic part36EB is elastically deformed, thereby opening/closing the air supply port30Ea.

The air stirring part33is an example of the stirring part, is configured by a metal plate having predetermined stiffness capable of suppressing deformation, which is caused due to a pressure of the compressed air to be supplied from the air supply port30Ea and a combustion pressure in the combustion chamber3, extends along an inner peripheral surface of the combustion chamber3, and has a shape covering the air-side lead valve30EB.

A side of the air stirring part33distant from the fuel supply port30Fe sandwiches the fixed part35EB of the air-side lead valve30EB between the side and the top surface30U, and is fixed to the top surface30U by the screw37EB.

The air stirring part33has such a shape that is curved in a direction in which an interval from the top surface30U increases from the side fixed to the top surface30U toward a tip end-side facing the valve part34B of the air-side lead valve30EB, and a part between the tip end-side of the air stirring part33and the air supply port30Ea to be opened/closed by the air-side lead valve30EB opens toward the fuel supply port30Fe.

The air stirring part33has a space, in which the air-side lead valve30EB can be elastically deformed, provided between the air stirring part and the top surface30U. Also, the air stirring part33has a curved surface, which faces the air-side lead valve30EB and with which the elastically deformed air-side lead valve30EB can be in contact.

Also, the air stirring part33has one side part, which faces the inner peripheral surface of the combustion chamber3and has a circular arc shape conforming to the inner peripheral surface of the combustion chamber3.

Thereby, the air stirring part33stirs the compressed air, which is supplied from the air supply port30Ea as the air-side lead valve30EB is opened, and generates a flow of the air to rotate with swirling in a spiral shape along the inner peripheral surface of the combustion chamber3. Also, the part between the tip end-side of the air stirring part33and the air supply port30Ea is opened toward the fuel supply port30Fe, so that the compressed air supplied from the air supply port30Ea flows toward the fuel supply port30Fe.

The nailing machine1A includes a blowback chamber6for collecting the gas to return the driver20and the piston21of the striking cylinder2. The blowback chamber6is provided around the striking cylinder2and is coupled to an inside of the striking cylinder2at an inlet/outlet60provided in the vicinity of the buffer material22.

The nailing machine1A has an exhaust valve7configured to exhaust the gas in the striking cylinder2and the combustion chamber3. The exhaust valve7is provided at one side part of the striking cylinder2with respect to the extension direction of the handle part11, and includes an exhaust piston71configured to be pushed by a gas introduced into the blowback chamber6, a first exhaust valve72configured to open/close a striking cylinder exhaust port23formed in the striking cylinder2, a second exhaust valve73configured to open/close a combustion chamber exhaust port32formed in the combustion chamber3, and a valve rod74coupling the exhaust piston71, the first exhaust valve72and the second exhaust valve73.

The exhaust piston71, the first exhaust valve72, the second exhaust valve73, and the valve rod74of the exhaust valve7are integrally made of metal. The exhaust valve7is configured so that movement of the exhaust piston71is to be transmitted to the first exhaust valve72and the second exhaust valve73via the valve rod74and the first exhaust valve72and the second exhaust valve73are thus to move in conjunction with the movement.

Also, the exhaust valve7includes an exhaust cylinder75to be coupled to the blowback chamber6, and an exhaust flow path forming cylinder76to be coupled to the striking cylinder exhaust port23and the combustion chamber exhaust port32. The exhaust cylinder75has a cylindrical space, in which the exhaust piston71can be slid, provided at one side part of the striking cylinder2with respect to the extension direction of the handle part11, and the exhaust valve7is configured to move in the extension direction of the valve rod74by a reciprocal operation of the exhaust piston71.

The exhaust flow path forming cylinder76has a cylindrical space, in which the first exhaust valve72and the second exhaust valve73can be slid, provided at one side part of the striking cylinder2with respect to the extension direction of the handle part11, and extends in a moving direction of the piston21.

The striking cylinder exhaust port23is formed by an outer opening23apenetrating the exhaust flow path forming cylinder76and an outside and an inner opening23bpenetrating the exhaust flow path forming cylinder76and the striking cylinder2, and is configured to communicate the outside and the inside of the striking cylinder2via the exhaust flow path forming cylinder76.

The inner opening23bof the striking cylinder exhaust port23is provided to face a top dead point position of the piston21so that the gas in the striking cylinder2can be exhausted to the outside by a return operation of the piston21from a bottom dead point position to the top dead point position. Also, the outer opening23aof the striking cylinder exhaust port23opens toward a side of the striking cylinder2, and the outer opening23aand the inner opening23bare arranged on one line.

The combustion chamber exhaust port32is formed by an outer opening32apenetrating the exhaust flow path forming cylinder76and the outside and an inner opening32bpenetrating the exhaust flow path forming cylinder76and the combustion chamber3, and is configured to communicate the outside and the inside of the combustion chamber3via the exhaust flow path forming cylinder76.

The outer opening32aof the combustion chamber exhaust port32opens toward a side of the striking cylinder2, and the outer opening32aand the inner opening32bare arranged with being vertically offset in the moving direction of the second exhaust valve73.

The first exhaust valve72has a substantially circular column shape conforming to an inner peripheral surface of the exhaust flow path forming cylinder76, and has a pair of sealing parts72a,72bhaving diameters capable of slidably contacting the inner surface of the exhaust flow path forming cylinder76and a flow path forming part72cprovided between the pair of sealing parts72a,72b, having a substantially circular column shape of a diameter smaller than the sealing parts72a,72band forming a space between the flow path forming part and the inner surface of the exhaust flow path forming cylinder76.

The second exhaust valve73has a substantially circular plate shape conforming to the inner peripheral surface of the exhaust flow path forming cylinder76and includes a sealing member73aprovided on an outer peripheral surface thereof. The sealing member73ais configured by an O-ring, for example, and the sealing member73ais configured to sliding contact the inner peripheral surface of the exhaust flow path forming cylinder76.

As shown inFIG. 1, the first exhaust valve72has such a configuration that when the flow path forming part72cis moved to a position facing the outer opening23aand the inner opening23bof the striking cylinder exhaust port23, the outer opening23aand the inner opening23bof the striking cylinder exhaust port23communicate with each other by the space formed between the inner surface of the exhaust flow path forming cylinder76and the flow path forming part72cand the striking cylinder exhaust port23opens.

Also, when the flow path forming part72cis moved to the position facing the outer opening23aand the inner opening23bof the striking cylinder exhaust port23, the upper exhaust flow path forming cylinder76of the flow path forming part72cis sealed by one sealing part72aand the lower exhaust flow path forming cylinder76is sealed by the other sealing part72b.

The sealing parts72a,72bare made of metal and are not provided with a sealing member such as an O-ring but implement a sealing structure by dimensions of outer diameters of the sealing parts72a,72band an inner diameter of the exhaust flow path forming cylinder76.

In a state where the striking cylinder exhaust port23is opened by the first exhaust valve72, the second exhaust valve73moves to the upper of the inner opening32bof the combustion chamber exhaust port32, so that the inner opening32band the outer opening32aof the combustion chamber exhaust port32communicate with each other therebetween by the exhaust flow path forming cylinder76and the combustion chamber exhaust port32opens, as shown inFIG. 1.

Also, in the state where the second exhaust valve73has moved to the upper of the inner opening32bof the combustion chamber exhaust port32, the sealing part72aof the first exhaust valve72is located below the outer opening32aof the combustion chamber exhaust port32, so that the striking cylinder exhaust port23and the combustion chamber exhaust port32are sealed therebetween by the sealing part72aof the first exhaust valve72.

In this way, the exhaust valve is configured by the first exhaust valve72, the striking cylinder exhaust port23and the exhaust flow path forming cylinder76, and the combustion chamber exhaust valve is configured by the second exhaust valve73, the combustion chamber exhaust port32and the exhaust flow path forming cylinder76.

Also, the first exhaust valve72, the striking cylinder exhaust port23and the exhaust flow path forming cylinder76are provided at one side part of the striking cylinder2, and the striking cylinder exhaust port23faces toward a side of the striking cylinder2. Also, the second exhaust valve73, the combustion chamber exhaust port32and the exhaust flow path forming cylinder76are provided at one side part of the combustion chamber3, and the combustion chamber exhaust port32faces toward a side of the combustion chamber3.

Also, the exhaust valve7has a buffer material77with which the exhaust piston71is to collide. The buffer material77is configured by an elastic member. The exhaust piston71collides with the buffer material77, so that a movement range of the exhaust valve7is restrained.

Also, the exhaust valve7includes a spring79configured to urge the valve rod74in a direction in which the first exhaust valve72is to close the striking cylinder exhaust port23and the second exhaust valve73is to close the combustion chamber exhaust port32. The spring79is an example of the urging member, is configured by a compression coil spring, in the embodiment, and is interposed between a spring receiving part24provided on a side surface of the striking cylinder2and a spring retainer74aattached to the valve rod74.

The spring retainer74ais configured to move integrally with the valve rod74. When the valve rod74is moved in a direction of compressing the spring79by the spring retainer74a, the first exhaust valve72opens the striking cylinder exhaust port23and the second exhaust valve73opens the combustion chamber exhaust port32. Also, when the valve rod74is moved in a direction in which the spring79is to extend, the first exhaust valve72closes the striking cylinder exhaust port23and the second exhaust valve73closes the combustion chamber exhaust port32.

The nailing machine1A has a contact member8provided in the nose part12. The contact member8is provided to be moveable along the extension direction of the nose part12, and is urged by a spring80in a direction in which it is to protrude from the nose part12. The contact member8is coupled to the exhaust valve7via a link81. The link81is attached to a side surface of the striking cylinder2to be rotatable about a shaft81d, which is a support point, and is coupled at one end to the contact member8. The link81is urged by the spring80such as a tensile coil spring, so that the contact member8rotates in the direction in which it protrudes from the nose part12.

Also, the other end of the link81is coupled to the exhaust valve7via a long hole portion78formed in the valve rod74. The long hole portion78is an opening extending in the moving direction of the valve rod74and is configured so that the valve rod74can move in a state where a position of the link81is fixed by the contact member8.

Thereby, the link81rotates in conjunction with movement of the contact member8, so that the exhaust valve7is actuated. Also, in the state where a position of the link81is fixed by the contact member8, the link81and the valve rod74are decoupled with shapes of the link81and of the long hole portion78and the exhaust valve7is actuated by the gas introduced into the blowback chamber6.

<Operation Example of Nailing Machine of Embodiment>

Subsequently, an operation of the nailing machine1A of the embodiment is described with reference to the respective drawings. In an initial state, the operation trigger16is not pulled, and the contact member8is not pressed to a material to be struck and is located at an initial position at which it is urged by the spring80and protrudes from the nose part12.

In a state where the contact member8is located at an initial position, the link81is urged by the spring80to push the long hole portion78of the valve rod74, so that the valve rod74is moved in the direction of compressing the spring79. As shown inFIG. 1, the flow path forming part72cof the first exhaust valve72of the exhaust valve7is moved to the position facing the outer opening23aand the inner opening23bof the striking cylinder exhaust port23, so that the striking cylinder exhaust port23is opened. Also, the second exhaust valve73is moved to the upper side of the inner opening32bof the combustion chamber exhaust port32in conjunction with the first exhaust valve72, so that the inner opening32band the outer opening32aof the combustion chamber exhaust port32communicate with each other therebetween by the exhaust flow path forming cylinder76and the combustion chamber exhaust port32is opened. Thereby, the striking cylinder2and the combustion chamber3are opened to the atmosphere.

Also, the head valve4is pressed by the spring44and is thus in the state where the valve surface40is in contact with the partitioning part50, i.e., in the state where the striking cylinder inlet51is closed by the head valve4. In this state, the head valve inlet53is connected to the actuation space52.

When the contact member8is pressed to a material to be struck, the link81is rotated in a direction of extending the spring80, so that the valve rod74is moved in the extension direction of the spring79in conformity to the rotation of the link81and the movement of the contact member8is transmitted to the exhaust valve7by the link81.

Also, the air valve30EV and the fuel valve30FV are opened in conjunction with the contact member8and an operation of the operation trigger16, so that the gasified fuel and the compressed air are supplied to the combustion chamber3. For example, when the contact member8is pressed to the material to be struck, the fuel valve30FV is opened, and when the operation trigger16is operated, the air valve30EV is opened. In the meantime, when the contact member8is pressed to the material to be struck and the operation trigger16is operated, the air valve30EV and fuel valve30FV may be opened at predetermined timings. Also, when the contact member8is pressed to the material to be struck, the air valve30EV and fuel valve30FV may be opened at predetermined timings.

When the compressed air is supplied to the air supply port30Ea, the valve part34EB of the air-side lead valve30EB is pushed by a pressure of the compressed air and the valve part34EB is elastically deformed in a direction of separating from the seal part30Es, so that the air supply port30Ea is opened. When the compressed air is supplied from the air supply port30Ea to the combustion chamber3, it is stirred by the air stirring part33, so that a flow of air to rotate with swirling in a spiral shape along the inner peripheral surface of the combustion chamber3is generated. Also, the part between the tip end-side of the air stirring part33and the air supply port30Ea is opened toward the fuel supply port30Fe, so that the compressed air supplied from the air supply port30Ea flows toward the fuel supply port30Fe.

Also, a degree of opening of the air-side lead valve30EB is restrained by the air stirring part33, and an amount of deformation of the elastic part36EB is suppressed from increasing and the plastic deformation is suppressed while securing a necessary degree of opening of the air-side lead valve30EB.

When the air valve30EV is closed and the supply of the predetermined amount of the compressed air is over, the pressure of pushing the valve part34EB of the air-side lead valve30EB is lowered, the valve part34EB is pressed to the seal part30Es by the elasticity of the elastic part36EB, and the air supply port30Ea is closed.

When the fuel is supplied to the fuel supply port30Fe, the valve part34FB of the fuel-side lead valve30FB is pushed by the pressure of the fuel and the valve part34FB is elastically deformed in the direction of separating from the seal part30Fs, so that the fuel supply port30Fe is opened. When the fuel is supplied from the fuel supply port30Fe to the combustion chamber3, it is supplied from the air supply port30Ea to the combustion chamber3and is mixed with compressed air stirred by the air stirring part33, so that the mixed gas of the compressed air and fuel is filled in the combustion chamber3.

When the fuel valve30FV is closed and the supply of the predetermined amount of the fuel is over, the pressure of pushing the valve part34FB of the fuel-side lead valve30FB is lowered, the valve part34FB is pressed to the seal part30Fs by the elasticity of the elastic part36FB and the urging force of the urging part38FB, and the fuel supply port30Fe is closed.

When the compressed air is supplied to the combustion chamber3, a pressure in the combustion chamber3rises. During the pressure rise in the combustion chamber3by the compressed air, the head valve4is pressed by the spring44, so that the valve surface40is kept in the contact state with the partitioning part50and the striking cylinder inlet51is closed by the head valve4. Therefore, even when the pressure in the combustion chamber3rises by the supply of the compressed air, the pressure does not rise in the striking cylinder2and the piston21is not actuated.

The contact member8is pressed to the material to be struck and the operation trigger16is operated, so that the air valve30EV and fuel valve30FV are opened and the air-side lead valve30EB are opened. Thereby, the compressed air is supplied from the air supply port30Ea, and the fuel-side lead valve30FB is opened, so that the fuel is supplied from the fuel supply port30Fe. Thereafter, when the ignition device31is actuated at a predetermined timing at which the air-side lead valve30EB is closed and the fuel-side lead valve30FB is closed, the mixed gas of compressed air and fuel in the combustion chamber3is combusted. When the mixed gas is combusted in the combustion chamber3, the pressure in the combustion chamber3rises.

As the pressure in the combustion chamber3rises, the force of pressing the valve part34EB of the air-side lead valve30EB in the state where the air supply port30Ea is closed to the seal part30Es increases, and flame and the like, which are generated as the mixed gas is combusted in the combustion chamber3, are prevented from flowing back from the air supply port30Ea.

Also, as the pressure in the combustion chamber3rises, the force of pressing the valve part34FB of the fuel-side lead valve30FB in the state where the fuel supply port30Fe is closed to the seal part30Fs increases, and the flame and the like, which are generated as the mixed gas is combusted in the combustion chamber3, are prevented from flowing back from the fuel supply port30Fe.

When the pressure in the combustion chamber3rises, the high temperature and high pressure gas is introduced from the head valve inlet53of the valve support member5into the actuation space52, and the pressure in the actuation space52rises, the high temperature and high pressure gas is applied to the actuation surface43of the head valve4, so that the head valve4is moved upward with compressing the spring44. Here, when the pressure in the actuation space52rises, the pressure is applied to the surface of the first seal part41facing the actuation space52, too. However, since an area of the actuation surface43is larger than the area of the surface of the first seal part41facing the actuation space52, the head valve4is moved upward with compressing the spring44.

As shown inFIG. 7, when the head valve4is moved upward, the striking cylinder inlet51is opened and the head valve inlet53is coupled to the striking cylinder inlet51. Thereby, the high temperature and high pressure gas is introduced from the combustion chamber3into the striking cylinder2via the striking cylinder inlet51, so that the pressure of the striking cylinder2rises.

When the pressure of the striking cylinder2rises, the piston21is pushed to move the piston21and the driver20in a direction of striking out a fastener, so that a fastener striking operation is performed. When the piston21and the driver20move in the direction of striking out a fastener, the gas (air) in a piston lower chamber25which is one chamber in the striking cylinder2partitioned by the piston21is enabled to flow from the inlet/outlet60into the blowback chamber6. Also, since the piston21passes through the inlet/outlet60with compressively deforming the buffer material22, a part of the high temperature and high pressure gas having driven the piston21is introduced into the blowback chamber6.

When the gas (air) in the striking cylinder2flows into the blowback chamber6and the pressure in the blowback chamber6rises, the exhaust piston71of the exhaust valve7is pushed, as shown inFIG. 5. In the state where the exhaust valve7and the link81are coupled via the long hole portion78formed in the valve rod74and the position of the link81is fixed by the contact member8, the link81and the valve rod74are decoupled, so that the exhaust valve7can move to the position at which it is to collide with the buffer material77. Since a moving amount of the exhaust valve7is restrained by the buffer material77, the durability of the exhaust valve7is improved.

Thereby, when the exhaust piston71of the exhaust valve7is pushed, the first exhaust valve72is moved to the position at which the flow path forming part72cfaces the outer opening23aand the inner opening23bof the striking cylinder exhaust port23, so that the striking cylinder exhaust port23is opened. Also, the second exhaust valve73is moved to the upper side of the inner opening32bof the combustion chamber exhaust port32in conjunction with the first exhaust valve72, so that the inner opening32band the outer opening32aof the combustion chamber exhaust port32communicate with each other therebetween by the exhaust flow path forming cylinder76and the combustion chamber exhaust port32is opened.

Therefore, the striking cylinder2and the combustion chamber3are opened to the atmosphere, and the gas in the combustion chamber3is exhausted from the combustion chamber exhaust port32to the outside. Also, the pressure in the combustion chamber3is lowered, so that the head valve4is pressed with the spring44and is moved to the position at which the valve surface40is in contact with the partitioning part50, and the striking cylinder inlet51is closed by the head valve4.

When the piston21and the driver20are further moved in the direction of striking out a fastener and the piston21is moved to a bottom dead point and collides with the buffer material22, the piston21and the driver20intend to move upward by the elasticity of the buffer material22. When the piston21moves to the upper of the inlet/outlet60through the inlet/outlet60, the gas (air) in the blowback chamber6in which the pressure has risen is introduced into the striking cylinder2and pushes the piston21. When the piston21is pushed, the air in the piston upper chamber25b, which is the other chamber in the striking cylinder2partitioned by the piston21, is exhausted from the striking cylinder exhaust port23to the outside, and the piston21and the driver20are returned to the top dead point.

When the contact member8separates from the material to be struck, the link81is urged by the spring80to push the long hole portion78of the valve rod74, so that the valve rod74is moved in the direction of compressing the spring79. Thereby, as shown inFIG. 1, the state where the first exhaust valve72opens the striking cylinder exhaust port23and the second exhaust valve73opens the combustion chamber exhaust port32is kept.

<Effect Example of Nailing Machine of Embodiment>

In the nailing machine1A of the embodiment, the compressed air and the fuel are supplied to the combustion chamber3, the mixed gas is combusted to generate the high pressure gas, and the piston21of the striking cylinder2is pushed by the high pressure gas, so that the force of pushing the fastener by the piston21and the driver20increases.

Thereby, it is possible to increase an output for striking a fastener, as compared to the gas combustion type nailing machine of the related art in which the ordinary pressure gas is used.

Also, the head valve4configured to open and close the striking cylinder inlet51between the combustion chamber3and the striking cylinder2is provided, so that it is possible to disable the striking cylinder2from actuating even though the compressed air is just supplied to the combustion chamber3. Also, the head valve4is actuated by the combustion pressure of the mixed gas, so that it is not necessary to provide a separate drive source for driving the head valve4. Thereby, it is possible to simplify structures of the head valve4and the drive mechanism thereof, to miniaturize the device and to save the cost.

Also, the combustion chamber3is provided above the striking cylinder2along the axial direction of the driver20and the piston21, so that it is possible to reduce the diameter of the combustion chamber3without reducing a volume of the combustion chamber3, as compared to a structure where the combustion chamber is provided around the striking cylinder2. Since the inside of the combustion chamber3is at the high pressure, it is necessary to make the combustion chamber3have predetermined strength. However, the diameter or the combustion chamber3can be made small, so that it is possible to secure the strength even when the combustion chamber3is made thin, and to implement miniaturization and weight saving of the entire device.

Also, the striking cylinder inlet51connecting the combustion chamber3and the striking cylinder2is provided on the axes of the driver20and the piston21, so that it is possible to make the diameter of the striking cylinder inlet51smaller than the striking cylinder2. As a result, it is possible to make the diameter of the head valve4smaller than the striking cylinder2. The diameter of the head valve4can be made small, so that it is possible to improve the moving speed of the head valve4and to shorten the time necessary to open the striking cylinder inlet51.

Also, since the gas to actuate the head valve4is the high temperature and high pressure gas, the viscosity thereof is lower, as compared to a case where the ordinary pressure gas is combusted. Thereby, it is possible to reduce a diameter of the head valve inlet53through which the gas to actuate the head valve4is to pass, and to reduce a diameter of a surrounding structure of the combustion chamber3and the head valve4.

The first seal part41provided to the head valve4has the first seal material41aprovided on the outer periphery thereof, and the first seal material41ais in contact with the inner surface of the valve support member5. Since the first seal material41ais fitted in the groove, the part to be exposed to the actuation space52is suppressed to the minimum. While the head valve4opens the striking cylinder inlet51and the head valve inlet53, the high temperature and high pressure gas is introduced from the striking cylinder inlet51below the head valve4. However, since the first seal material41ais fitted in the groove, the part to be exposed is suppressed to the minimum.

In the meantime, the high temperature and high pressure gas is applied to the actuation surface43of the head valve4, so that while the head valve4moves and the head valve4opens the striking cylinder inlet51and the head valve inlet53, the first seal part41passes by the head valve inlet53and the first seal material41ais thus exposed to the high temperature and high pressure gas. However, since the first seal material41ais made of metal, the first seal material41ais suppressed from being influenced by heat.

Also, the second seal part42has the second seal material42aprovided on the outer periphery thereof, and the second seal material42ais in contact with the inner surface of the valve support member5. Since the second seal material42ais fitted in the groove, the part to be exposed to the actuation space52is suppressed to the minimum.

The high temperature and high pressure gas is applied to the actuation surface43of the head valve4, so that while the head valve4moves and the head valve4opens the head valve inlet53, the second seal material42ais suppressed from being influenced by heat because the exposure of the second seal material42ais suppressed. Also, while the head valve4moves and the head valve4opens the head valve inlet53, since the second seal part42does not pass by the head valve inlet53, the second seal material42ais suppressed from being exposed to the high temperature and high pressure gas.

Therefore, the durability of the seal material is improved and the desired performance can be maintained for the longtime use. Also, one seal material (the first seal material41a) of the head valve4is made of metal, so that the friction with the valve support member5is reduced and it is possible to reduce the diameter of the head valve4and to improve the moving speed of the head valve4. Also, the head valve4has the seal material made of metal. Therefore, even when the seal material is arranged on the end face along the moving direction of the head valve4and is exposed to the flow path of the gas, it is possible to improve the durability of the seal part.

However, when the seal material made of metal is used, the higher contact pressure is required, as compared to a configuration where a seal material such as an elastic body of rubber is used, so that it is necessary to use the high-load spring. Therefore, in the nailing machine1A of the embodiment, the spring44is arranged on the same axis of the head valve4, which is a center of the head valve4, so that it is possible to use the high-load spring without enlarging the main body part10. Also, the concave part45is formed in the axial direction of the head valve4and is overlap-arranged so that the spring44is to enter therein. Thereby, it is possible to reduce the protruding amount of the spring44from the head valve4, so that it is possible to suppress a size of the main body part10in a height direction from increasing. Also, since the spring44is to enter the concave part45of the head valve4, the diameter of the spring44can be made smaller than the striking cylinder2, so that it is possible to suppress a size of the main body part10in a radial direction from increasing.

When the compressed air is supplied to the air supply port30Ea, the valve part34EB of the air-side lead valve30EB is pushed by the pressure of the compressed air and the elastic part36EB is elastically deformed in the direction in which the valve part34EB separates from the seal part30Es, so that the air supply port30Ea is opened.

Also, when the supply of the compressed air is over, the pressure of pushing the valve part34EB of the air-side lead valve30EB is lowered and the valve part34EB is pressed to the seal part30Es by the elasticity of the elastic part36EB, so that the air supply port30Ea is closed.

Thereby, it is possible to open/close the air supply port30Ea by the air-side lead valve30EB having the simple configuration, depending on whether the compressed air is supplied.

Also, in the air-side lead valve30EB of which the air supply port30Ea is closed, as the pressure in the combustion chamber3rises, the force of pressing the valve part34EB to the seal part30Es increases, in addition to the elasticity of the elastic part36EB, so that the state where the valve part34EB is pressed to the seal part30Es is kept.

The air-side lead valve30EB is provided on the top surface30U, and the air supply port30Ea is not exposed to the combustion chamber3in the state where the air supply port30Ea is closed by the valve part34EB.

Thereby, it is possible to suppress the flame and the like, which are generated as the mixed gas in the combustion chamber3is combusted, from flowing back from the air supply port30Ea to the air pipe conduit30Ei, and to suppress damages of the air pipe conduit30Ei and the air valve30EV. Also, it is not necessary for the air pipe conduit30Ei to have the pressure resistance performance corresponding to the combustion pressure, so that it is possible to lower the pressure resistance performance. Thereby, it is possible to use a flexible material and to suppress the damage, which is caused due to vibrations and the like upon the striking.

Also, the degree of opening of the air-side lead valve30EB is restrained by the air stirring part33, and the deformation amount of the air-side lead valve30EB, which is to be deformed by the pressure of the compressed air, is suppressed from increasing, so that it is possible to suppress the air-side lead valve30EB from being plastically deformed.

Also, the air stirring part33has the curved surface with which the elastically deformable air-side lead valve30EB can be in contact. Therefore, even when the air-side lead valve30EB, which is to be deformed by the pressure of the compressed air, is pressed to the air stirring part33, it is possible to suppress the plastic deformation such as a fold line to be formed on the air-side lead valve30EB.

When the fuel is supplied to the fuel supply port30Fe, the valve part34FB of the fuel-side lead valve30FB is pushed by the pressure of the fuel and the elastic part36FB is elastically deformed in the direction in which the valve part34FB is to separate from the seal part30Fs, so that the fuel supply port30Fe is opened.

Also, when the supply of the fuel is over, the pressure of pushing the valve part34FB of the fuel-side lead valve30FB is lowered and the valve part34FB is pressed to the seal part30Fs by the elasticity of the elastic part36FB and the urging of the urging part38FB, so that the fuel supply port30Fe is closed.

Thereby, it is possible to open/close the fuel supply port30Fe by the fuel-side lead valve30FB having the simple configuration, depending on whether the fuel is supplied.

Also, in the fuel-side lead valve30FB of which the fuel supply port30Fe is closed, as the pressure in the combustion chamber3rises, the force of pressing the valve part34FB to the seal part30Fs increases, in addition to the elasticity of the elastic part36FB and the urging of the urging part38FB, so that the state where the valve part34FB is pressed to the seal part30Fs is kept.

The fuel-side lead valve30FB is provided on the top surface30U, and the air fuel supply port30Fe is not exposed to the combustion chamber3in the state where the fuel supply port30Fe is closed by the valve part34FB.

Thereby, it is possible to suppress the flame and the like, which are generated as the mixed gas in the combustion chamber3is combusted, from flowing back from the fuel supply port30Fe to the fuel pipe conduit30Fi, and to suppress damages of the fuel pipe conduit30Fi and the fuel valve30FV. Also, it is not necessary for the fuel pipe conduit30Fi to have the pressure resistance performance corresponding to the combustion pressure, so that it is possible to lower the pressure resistance performance. Thereby, it is possible to use a flexible material and to suppress the damage, which is caused due to vibrations and the like upon the striking. Also, even when the fuel remains in the fuel supply port30Fe and the fuel pipe conduit30Fi, the remaining fuel is suppressed from being imperfectly combusted and the soot is suppressed from being attached into the fuel pipe conduit30Fi.

Here, an amount of the fuel to be supplied to the combustion chamber3is measured by a method of sending liquefied fuel to a small measurement chamber provided in the fuel valve30FV and measuring the same by a volume. For this reason, when a gas is mixed in the measurement chamber, it is not possible to perform correct measurement, so that it is not possible to supply a prescribed amount of fuel. Also, in the case of a check valve for which a lead valve is adopted, a gap may be generated between the valve part and the seal part due to bending of the lead valve.

The gap is generated between the valve part and the seal part, so that when the compressed air is mixed in the fuel pipe conduit30Fi, it is not possible to normally supply the fuel because the pressure of the compressed air is higher than the supply pressure of the fuel.

Therefore, the fuel-side lead valve30FB is provided with the urging part38FB for urging the valve part34FB in the direction of the seal part30Fs, so that the force of pressing the valve part34FB to the seal part30Fs increases in the closed state of the fuel supply port30Fe.

Thereby, it is possible to suppress the fuel-side lead valve30FB from vibrating, which is caused when the valve part34FB is floated from the seal part30Fs and the valve part34FB is floated from the seal part30Fs by the pressure of the compressed air stirred by the air stirring part33, the combustion pressure and the like, so that it is possible to securely seal the valve part34FB and the seal part30Fs of the fuel-side lead valve30FB. Therefore, it is possible to suppress the gas such as the compressed air from being mixed from the fuel pipe conduit30Fi into the fuel valve30FV, so that it is possible to normally measure the fuel. Also, it is possible to normally supply the fuel.

Also, when the compressed air is supplied from the air supply port30Ea to the combustion chamber3, the air is stirred by the air stirring part33, so that a flow of the air to rotate with swirling in a spiral shape along the inner peripheral surface of the combustion chamber3is generated. Also, the air-side lead valve30EB is provided with the fixed part35EB at the side distant from the fuel supply port30Fe with respect to the arrangement of the fuel supply port30Fe and the air supply port30Ea and the side of air-side lead valve30EB facing toward the fuel supply port30Fe is opened. Therefore, the part between the tip end-side of the air stirring part33and the air supply port30Ea is opened toward the fuel supply port30Fe, so that the compressed air supplied from the air supply port30Ea flows toward the fuel supply port30Fe.

Thereby, it is possible to widely spread the compressed air over the entire combustion chamber3without using a fan to be driven by a motor, to promote the mixing of the compressed air and the fuel supplied from the fuel supply port30Fe, and to suppress a distribution of the mixed gas from being inclined to one side in the combustion chamber3, so that it is possible to improve the combustion efficiency.

<Other Embodiments of Head Part>

FIG. 14is a perspective view depicting a second embodiment of the head part. A head part30B is provided with the ignition device31. Also, the head part30B is provided with the fuel supply port30Fe to which the fuel is to be supplied and the air supply port30Ea to which the compressed air is to be supplied. The head part30B has the fuel supply port30Fe and the air supply port30Ea provided in parallel with each other.

Also, the head part30B has the fuel-side lead valve30FB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the fuel supply port30Fe and the air-side lead valve30EB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the air supply port30Ea. Also, the head part30B has the air stirring part33configured to stir the compressed air to be supplied from the air supply port30Ea.

In the meantime, the air-side lead valve30EB and the air stirring part33of the head part30B of the second embodiment have the same configurations as the head part30A of the first embodiment, and the descriptions thereof are omitted. Also, the elastic part36FB of the fuel-side lead valve30FB has a flat plate shape.

The fuel-side lead valve30FB includes an urging member39FB for urging the valve part34FB in the direction of the seal part30Fs. The urging member39FB is configured by an elastic metal plate and has a bent part having a predetermined shape. The urging member39FB is fixed with the screw37FB, together with the fuel-side lead valve30FB, and is configured to push the valve part34FB at a tip end-side thereof.

Thereby, the force of pressing the valve part34FB to the seal part30Fs increases in the closed state of the fuel supply port30Fe, so that it is possible to suppress the fuel-side lead valve30FB from vibrating, which is caused when the valve part34FB is floated from the seal part30Fs and the valve part34FB is floated from the seal part30Fs by the pressure of the compressed air stirred by the air stirring part33, the combustion pressure and the like.

FIG. 15is a perspective view depicting a third embodiment of the head part. A head part30C is provided with the ignition device31. Also, the head part30C is provided with the fuel supply port30Fe to which the fuel is to be supplied and the air supply port30Ea to which the compressed air is to be supplied. The head part30C has the fuel supply port30Fe and the air supply port30Ea provided in parallel with each other.

Also, the head part30C has the fuel-side lead valve30FB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the fuel supply port30Fe and the air-side lead valve30EB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the air supply port30Ea. Also, the head part30C has the air stirring part33configured to stir the compressed air to be supplied from the air supply port30Ea.

In the meantime, the air-side lead valve30EB and the air stirring part33of the head part30C of the third embodiment have the same configurations as the head part30A of the first embodiment, and the descriptions thereof are omitted. Also, the elastic part36FB of the fuel-side lead valve30FB has a flat plate shape.

The head part30C has a shield part33C provided at a side facing the air supply port30Ea of the fuel supply port30Fe and configured to shield a flow of the compressed air supplied from the air supply port30Ea. The shield part33C is configured by providing a convex part, which faces inward from an inner peripheral surface of the head part30C and protrudes from the top surface30U, between the air supply port30Ea and fuel supply port30Fe.

Thereby, the air, which is supplied from the air supply port30Ea as the air-side lead valve30EB is opened, is shielded from flowing in the direction of the fuel supply port30Fe along the top surface30U by the shield part33C, so that it is possible to suppress the valve part34FB of the fuel-side lead valve30FB from floating from the seal part30Fs without providing the fuel-side lead valve30FB with the urging part and without urging the fuel-side lead valve30FB by the urging member.

FIG. 16is a perspective view depicting a fourth embodiment of the head part. A head part30D is provided with the ignition device31. Also, the head part30D is provided with the fuel supply port30Fe to which the fuel is to be supplied and the air supply port30Ea to which the compressed air is to be supplied. The head part30D has the fuel supply port30Fe and the air supply port30Ea provided in parallel with each other.

Also, the head part30D has the fuel-side lead valve30FB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the fuel supply port30Fe and the air-side lead valve30EB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the air supply port30Ea. Also, the head part30D has the air stirring part33configured to stir the compressed air to be supplied from the air supply port30Ea.

In the meantime, the air-side lead valve30EB and the air stirring part33of the head part30D of the fourth embodiment have the same configurations as the head part30A of the first embodiment, and the descriptions thereof are omitted. Also, the elastic part36FB of the fuel-side lead valve30FB has a flat plate shape.

The head part30D has a step part30Dr, into which the fuel-side lead valve30FB is to enter, provided on the top surface30U. The step part30Dr has substantially the same depth as a thickness of the fuel-side lead valve30FB, and is configured by providing a concave part having a shape in which the fuel-side lead valve30FB is to entirely enter, in the fourth embodiment, and a surface of the fuel-side lead valve30FB facing the combustion chamber3and the top surface30U arte substantially the same.

Thereby, the air, which is supplied from the air supply port30Ea as the air-side lead valve30EB is opened and flows in the direction of the fuel supply port30Fe along the top surface30U, is suppressed from colliding between the valve part34FB and the seal part30Fs of the fuel-side lead valve30FB, so that it is possible to suppress the valve part34FB of the fuel-side lead valve30FB from floating from the seal part30Fs without providing the fuel-side lead valve30FB with the urging part and without urging the fuel-side lead valve30FB by the urging member. In the meantime, a step part into which the valve part34FB, not the entire fuel-side lead valve30FB, is to enter may be provided.

FIG. 17is a perspective view depicting a fifth embodiment of the head part. A head part30E is provided with the ignition device31. Also, the head part30E is provided with the fuel supply port30Fe to which the fuel is to be supplied and the air supply port30Ea to which the compressed air is to be supplied. The head part30E has the fuel supply port30Fe provided at a position distant from the air supply port30Ea.

Also, the head part30E has the fuel-side lead valve30FB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the fuel supply port30Fe and the air-side lead valve30EB configured to suppress back-flow of flame, gas and the like from the combustion chamber3to the air supply port30Ea. Also, the head part30E has the air stirring part33configured to stir the compressed air to be supplied from the air supply port30Ea.

In the meantime, the air-side lead valve30EB and the air stirring part33of the head part30D of the fifth embodiment have the same configurations as the head part30A of the first embodiment, and the descriptions thereof are omitted. Also, the elastic part36FB of the fuel-side lead valve30FB has a flat plate shape.

The fuel-side lead valve30FB has the fixed part35FB provided between the valve part34FB configured to open/close the fuel supply port30Fe and the air supply port30Ea, and the fixed part35EB is provided at a side close to the air supply port30Ea with respect to the arrangement of the fuel supply port30Fe and the air supply port30Ea.

The fixed part35FB of the fuel-side lead valve30FB, which is arranged at a side close to the air supply port30Ea at which the valve part34FB covers the fuel supply port30Fe, is fixed to the top surface30U of the head part30E by the screw37FB.

Thereby, the fixed part35FB of the fuel-side lead valve30FB is arranged at an upstream side with respect to the flow of the compressed air, which is supplied from the air supply port30Ea as the air-side lead valve30EB is opened and is stirred to swirl by the air stirring part33, and the valve part34FB and the seal part30Fs are arranged at a downstream side, so that it is possible to suppress the valve part34FB from floating from the seal part30Fs without providing the fuel-side lead valve30FB with the urging part and without urging the fuel-side lead valve30FB by the urging member.

FIG. 18is a perspective view depicting a sixth embodiment of the head part. A head part30F is provided with the ignition device31. Also, the head part30F is provided with the fuel supply port30Fe to which the fuel is to be supplied and the air supply port30Ea to which the compressed air is to be supplied. The head part30F has the fuel supply port30Fe and the air supply port30Ea provided in parallel with each other.

Also, the head part30F has the air stirring part33configured to stir the compressed air that is to be supplied from the air supply port30Ea. The air stirring part33is fixed to the top surface30U by the screw37EB at a side distant from the fuel supply port30Fe.

The air stirring part33has such a shape that it is curved in a direction in which an interval from the top surface30U increases from the side fixed to the top surface30U toward the tip end-side facing the air supply port30Ea, and the part between the tip end-side of the air stirring part33and the air supply port30Ea is opened toward the fuel supply port30Fe. Also, one side part of the air stirring part33, which faces the inner peripheral surface of the combustion chamber3, has a circular arc shape conforming to the inner peripheral surface of the combustion chamber3.

Thereby, the air stirring part33stirs the compressed air supplied from the air supply port30Ea and generates a flow of the air to rotate with swirling in a spiral shape along the inner peripheral surface of the combustion chamber3. Also, the part between the tip end-side of the air stirring part33and the air supply port30Ea is opened toward the fuel supply port30Fe, so that the compressed air supplied from the air supply port30Ea flows toward the fuel supply port30Fe.

Therefore, the compressed air is widely spread to involve the fuel supplied into the combustion chamber3over the entire combustion chamber3, the mixing of the fuel and the compressed air is promoted and a distribution of the mixed gas is suppressed from being inclined to one side in the combustion chamber3, so that it is possible to improve the combustion efficiency.

FIG. 19is a perspective view depicting a seventh embodiment of the head part. A head part30G is provided with the ignition device31. Also, the head part30G is provided with the fuel supply port30Fe to which the fuel is to be supplied and an air supply port nozzle30En to which the compressed air is to be supplied. The head part30G has the fuel supply port30Fe and the air supply port nozzle30En provided in parallel with each other.

The air supply port nozzle30En is an example of the stirring part, wherein a cylindrical member is erected from an air supply port (not shown) and at least one supply port30Ee is provided on a circumferential surface. The air supply port nozzle30En is provided so that the supply port30Ee is to face toward the fuel supply port30Fe.

Thereby, the compressed air supplied from the supply port30Ee of the air supply port nozzle30En flows toward the fuel supply port30Fe and rotates with swirling along the inner peripheral surface of the combustion chamber3.

Therefore, the compressed air is widely spread over the entire combustion chamber3, the mixing of the fuel and the compressed air is promoted and a distribution of the mixed gas is suppressed from being inclined to one side in the combustion chamber3, so that it is possible to improve the combustion efficiency. In the meantime, the respective embodiment may be combined. For example, the second embodiment shown inFIG. 14where the fuel-side lead valve30FB is provided with the urging member39FB may be provided with the shield part33C of the third embodiment shown inFIG. 15. Also, the air-side lead valve30EB and fuel-side lead valve30FB are provided to the top surface30U as the inner wall surface of the combustion chamber3but may be provided on an inner surface as the inner wall surface of the combustion chamber3. Also, in the embodiments, the air is used as the oxidant, and the mixed gas of the compressed air as the compressed oxidant and the fuel is used for actuation. However, the oxidant is not limited to the compressed air and the other oxidants may be used inasmuch as the oxidant contains oxygen necessary for combustion of the fuel. For example, oxygen, ozone, nitrogen monoxide and the like may also be used, instead of the air.