JP2011245621A - Gas internal combustion type nailing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure safety by preventing or suppressing the generation of excessive energy when supercharging pressure exceeds a set pressure value.SOLUTION: In a gas internal combustion type nailing machine having a hammering cylinder 5 housing a hammering piston 6, a combustion chamber 11 openably arranged by upward/downward movement of a cylindrical movable housing 8 above the hammering cylinder 5, a compressor 25 for supplying compressed air for supercharging into the combustion chamber 11, and a fuel supplying unit 19 for supplying fuel gas into the combustion chamber 11, mixing, igniting, and combusting the supercharged fuel gas and air, the operation of a trigger 40 for igniting and combusting is invalidated when the supercharging pressure by the compressed air for supercharging supplied into the combustion chamber 11 exceeds the set pressure value.

Description

  The present invention relates to a gas internal combustion nailer, and more particularly, to a gas internal combustion nailer in which safety measures are taken against an unexpected increase in supercharging pressure.

  A gas internal combustion nailer has been known (see, for example, Patent Document 1), and in such a nailing machine, compressed air is supercharged into the combustion chamber to increase output energy. Things are also known.

  In these known gas internal combustion nailers, an appropriate air-fuel ratio can be maintained in order to ensure a good combustion state. For this purpose, the amount of fuel supplied depends on the amount of air supplied to the combustion chamber. A means for adjusting the injection amount is equipped.

  For example, according to a known supercharged gas internal combustion nailing machine, a structure is provided in which compressed air and fuel are respectively supplied into the combustion chamber through separate supply pipes, and are supplied into the combustion chamber. The supply of a fixed amount of fuel is performed using a fixed amount valve controlled by a mechanical or electronic control means arranged in a fuel supply pipe (for example, see Patent Document 2).

Japanese Patent Publication No. Hei 4-48589 US Pub. 2004/0134961 A1

  In the gas internal combustion nailer described above, the fuel supply amount is adjusted in accordance with the amount of air supplied in order to maintain an appropriate air-fuel ratio. And the fuel supply amount are linked to each other, and the fuel supply using a metering valve controlled by the mechanical or electronic control means of the gas internal combustion nailing machine of Patent Document 2 described above Is no exception.

  By the way, according to the relationship between the supply amounts of the air and the fuel supplied as described above, for example, in a supercharged gas internal combustion nailer, excessive compressed air is supplied for some reason and supercharging. Even when a situation in which the pressure exceeds a predetermined pressure value occurs, as long as compressed air is continuously supplied, fuel is supplied in accordance with the supplied air amount.

  However, in combustion at a high supercharging pressure exceeding a predetermined pressure value, the explosion energy due to combustion exceeds the set output energy. And generation | occurrence | production of such excessive output energy will place a physical excessive load on a nail driver, and will have a bad influence on durability and safety | security of a nail driver. Therefore, effective measures for eliminating such adverse effects are required from the viewpoint of ensuring durability and safety in the nailing machine.

  In order to solve the above-described problems, the present invention is configured such that when the supercharging pressure exceeds a set pressure value, the fuel supply is shut off, the ignition switch is disabled, the supercharging pressure is reduced by expanding the combustion chamber volume, etc. Gas internal combustion nailing machine that can ensure the durability and safety of nailing machine by taking special measures and preventing or suppressing the generation of excessive combustion energy due to combustion exceeding the set output energy Is to provide.

  That is, the invention according to claim 1 of the present invention supplies a striking cylinder that slidably houses a striking piston, a combustion chamber that can be opened and closed above the striking cylinder, and compressed air for supercharging. In a gas internal combustion nailing machine comprising a compressor for performing combustion and a fuel supply device for supplying fuel gas, and mixing and igniting combustion of the supercharged fuel gas and air, the supercharging supplied into the combustion chamber When the supercharging pressure by the compressed air for the pressure exceeds a set pressure value, the operation of the trigger for performing the ignition combustion is invalidated.

  According to a second aspect of the present invention, in the first aspect, the invalidation of the operation of the trigger is performed by electric circuit control of an ignition control device based on a detection signal of a pressure sensor that detects a pressure exceeding the set pressure value in the combustion chamber. This is realized by preventing the ignition combustion switch from being turned ON.

  According to a third aspect of the present invention, in the first aspect of the invention, the fuel gas and air mixed in the combustion chamber are supercharged into the combustion chamber by pressing the contact member of the switch for ignition combustion by operating the trigger. The ignition is burned, and the operation of the trigger is invalidated by the cylinder mechanism that operates in response to the pressure exceeding the set pressure value in the combustion chamber, so that the contact member of the switch is not engaged with the trigger. It is realized by moving to a position.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the fuel gas and air mixed in the combustion chamber are supercharged into the combustion chamber by pressing the contact member of the switch for ignition combustion by operating the trigger. The trigger operation is invalidated by moving a piston rod of a cylinder mechanism that operates in response to a pressure exceeding the set pressure value in the combustion chamber to a position that interferes with the trigger. It is realized to be realized.

  The invention according to claim 1 of the present invention invalidates the operation of the trigger for performing the ignition combustion when the supercharging pressure by the compressed air for supercharging supplied into the combustion chamber exceeds a set pressure value. Therefore, it is possible to reliably prevent the start of the nailing machine, even under unexpectedly high pressure that adversely affects the durability and safety of the nailing machine even if an unexpected increase in supercharging pressure occurs. Excessive explosive energy is not generated by combustion.

  According to a second aspect of the present invention, the switch for ignition combustion is prevented from being turned on by electric circuit control of the ignition control device based on a detection signal of a pressure sensor that detects a pressure exceeding a set pressure value in the combustion chamber. Therefore, if the supercharging pressure exceeds the set pressure value, the switch will not operate and ignition will be impossible, so even if the supercharging pressure rises for some unexpected reason, Generation of excessive explosion energy due to combustion under high pressure that adversely affects the durability and safety of the machine is reliably prevented.

  According to the invention of claim 3, by pressing the contact member of the switch for ignition combustion by the operation of the trigger, the mixed gas of fuel gas and air supercharged in the combustion chamber is ignited and burned, and The switch contact member is moved to a position not engaged with the trigger by a cylinder mechanism that operates in response to a pressure exceeding the set pressure value in the combustion chamber, so when the set pressure value is exceeded, the switch contact member is pressed. Since this is not possible, activation of the nailer can be reliably prevented.

  According to the fourth aspect of the invention, since the piston rod of the cylinder mechanism that operates in response to the pressure exceeding the set pressure value in the combustion chamber is moved to a position that interferes with the trigger, the trigger is effectively operated. I can't. Therefore, starting of the nailing machine can be prevented.

The longitudinal cross-sectional view of the principal part of the gas internal combustion type nailing machine of one Embodiment of this invention FIG. 1 is a longitudinal sectional view showing the operating state of the gas internal combustion nailer of FIG. The longitudinal cross-sectional view of the principal part of the gas internal combustion type nailer of other embodiment of this invention FIG. 3 is a longitudinal sectional view showing the operating state of the gas internal combustion nailer of FIG. The longitudinal cross-sectional view of the principal part of the gas internal combustion type nail driver of further another embodiment of this invention The longitudinal cross-sectional view of the principal part of the gas internal combustion type nailer of another embodiment of this invention FIG. 6 is a longitudinal section showing the operating state of the gas internal combustion nailer of FIG. 1 is a longitudinal sectional view showing a basic configuration of a gas internal combustion nailer according to the present invention. The longitudinal cross-sectional view of the principal part which shows the operating state of the gas internal combustion type nailer of FIG.

  Embodiments of the present invention will be described below. First, a gas internal combustion nailing machine A which is the premise thereof will be described with reference to FIGS. 8 and 9, and an excess of compressed air for supercharging supplied into the combustion chamber will be described. The form when the supply pressure exceeds the set pressure value will be described individually.

  FIGS. 8 and 9 show a gas internal combustion nailing machine. This nailing machine has a nailing machine body 1 for storing a drive mechanism, a gas fuel cartridge and the like, and a grip formed integrally with the nailing machine body 1. 2 and a nose portion 3 protruding from the lower part of the nailing machine body 1 in the figure. Reference numeral 4 denotes a magazine for supplying nails to the injection port of the nose portion 3.

  The drive mechanism is located at the upper part of the cylindrical impact cylinder 5, the impact piston 6 that reciprocates in the up-and-down direction in the impact cylinder 5, the driver 7 fixed to the impact piston 6, and the impact cylinder 5. A combustion chamber 11, which is a space surrounded by a cylindrical movable housing 8 and an upper cylinder head portion 10 and partitioned by the upper surface of the impact piston 6, and an ignition plug attached to the upper cylinder head portion 10 of the combustion chamber 11 12, a stirring fan 15 driven by a motor 14 for mixing the combustible fuel gas supplied from the gas fuel cartridge 13 and air.

  The combustion chamber 11 and the striking cylinder 5 are partitioned by a partition member 16 and communicate with each other through an opening 18 having a check valve 17 made of a leaf spring.

  Next, a supply port 20 is formed in the upper end side wall of the striking cylinder 5, and an annular head valve 21 opens or closes the supply port 20 and the combustion chamber 11 between the striking cylinder 5 and the combustion chamber 11. Is provided. The head valve 21 is disposed so as to be movable up and down along the upper outer surface of the striking cylinder 5 and is urged upward so as to always close the supply port 20 by a push-up spring 22 provided at the lower part thereof. The spring force of the push-up spring 22 is set to such an extent that the head valve 21 cannot be kept closed when the internal pressure in the combustion chamber 11 becomes high due to combustion.

  In addition, a contact member 23 that performs an initial movement for substantially starting the drive mechanism is provided. The contact member 23 is spring-biased so that its lower end protrudes from the lowermost portion of the nose portion 3 in a state where it is not used for nailing, and the upper end of the rod member 24 provided on the upper portion of the contact member 23 is movable in the combustion chamber 11. Connected to the lower end of the housing 8, the movable housing 8 of the combustion chamber 11 is moved downward and released to the atmosphere.

  Further, the gas internal combustion nailer has a supercharged compressor 25 in the rear space of the nailer body 1. The compressor 25 is a reciprocating type, and the piston 30 reciprocates the piston 30 in a cylinder 28 opened to the air suction port 26 and the compressed air supply pipe 27, thereby compressing the air taken in from the suction port 26 by the piston 30. A suction valve 31 and a discharge valve (not shown) are provided at the suction port 26 and the compressed air supply tube 27, respectively. The discharge valve is a plate-like check valve that operates in opposite directions. The compressed air for supercharging is supplied from the compressed air supply pipe 27 to the combustion chamber 11.

  The reciprocating motion of the piston 30 is performed by the motor 32, the driving force is transmitted from the gear 33 of the motor shaft of the motor 32 to the crank gear 36 through the meshing of the two bevel gears 34, and the rotation of the crank gear 36 is transmitted to the connecting rod 37. As a result, the piston 30 held swingably at the upper end of the connecting rod via a piston pin is reciprocated in the cylinder 28 for intake and discharge.

  A fuel supply device 19 including a gas fuel cartridge 13 is attached to the lower part of the grip 2. The gas fuel supplied from the fuel supply device 19 is supplied into the combustion chamber 11 through the fuel supply pipe 38. The fuel supply pipe 38 is connected in the middle of the compressed air supply pipe 27, and the gas fuel is supplied into the combustion chamber 11 from the compressed fuel supply pipe 39 together with the compressed air.

  The fuel supply device 19 includes means for adjusting the fuel injection amount in accordance with the amount of air supplied to the combustion chamber 11 so as to maintain an appropriate air-fuel ratio for ensuring a good combustion state. It is assumed that it is equipped.

  Next, the contact member 23 is pushed upward to move the movable housing 8 upward to form a sealed combustion chamber 11, and the supercharged compressor 25 drives the motor 32 in association with the operation of the trigger. Then, the operation is started, and the supply of gas fuel, ignition by the spark plug 12, and the like are performed.

  That is, when the contact member 23 pressed against a not-shown nailing material is pushed upward in the drawing, the movable housing 8 of the combustion chamber 11 moves upward as shown in FIG. The compressor 25 is driven to operate by the drive of the motor 32 and the compressed air is fed through the compressed air supply pipe 27. At the same time, the gas fuel is supplied from the gas fuel cartridge 13 to the fuel supply pipe. The compressed air and the fuel are merged into the compressed fuel supply pipe 39 and supplied into the combustion chamber 11. This is agitated and mixed by the agitating fan 15 so as to be uniform, and the microswitch S is turned on by the operation of the trigger 40 to ignite the spark plug 12 so that the mixed fuel in the combustion chamber 11 is combusted.

  The high pressure gas generated by the combustion of the mixed fuel in the combustion chamber 11 pushes down the head valve 21 against the spring 22 and opens the opening to the supply port 20, so that the combustion gas pressure is supplied into the striking cylinder 5 and the striking piston. 6 is driven, and the driver 7 hits the nail and drives it into a predetermined position of the nail material.

  Further, when the striking piston 6 moves down to the bottom dead center, the gas in the striking cylinder 5 is rapidly cooled and the volume is reduced, so that the striking cylinder 5 has a negative pressure, and the striking piston 6 moves upward. The increase in pressure in the cylinder space accompanying the upward movement of the striking piston 6 opens the check valve 17 of the partition member 16, and the striking piston 6 moves to the top dead center.

  When the operation of the trigger 40 is released with the end of the nail driving and the pressing of the contact member 23 against the nail-dried material is released, the contact member 23 is pushed down by the return force of the spring and moves downward. In conjunction with this, the movable sleeve portion of the combustion chamber 11 moves downward, the combustion chamber 11 is opened, fresh air flows into the combustion chamber 11 from the seal portion, and the next nailing is prepared.

[Embodiment 1]
In this embodiment, in the gas internal combustion nailer, when the supercharging pressure by the compressed air for supercharging supplied into the combustion chamber 11 exceeds a set pressure value, the fuel by the fuel supply device It is related with the means which interrupts | blocks supply.

  That is, as shown in FIG. 1, the control valve 41 is provided in the middle of the fuel supply pipe 38 that supplies the fuel gas from the fuel supply device 19. A valve body 43 is slidably disposed inside the valve cylinder 42 of the control valve 41, and the upper end of the valve cylinder 42 is connected to a pressure extraction pipe 44 branched from the compressed air supply pipe 27. A push-up spring 45 that urges the valve body 43 upward is disposed below the valve cylinder 42. Further, a fuel supply pipe 38 is opened on the side wall of the valve cylinder 42.

  If the supercharging pressure in the combustion chamber 11 is equal to or lower than a predetermined set pressure value, the valve body 43 of the control valve 41 is pushed upward by the push-up spring 45 as shown in the figure, and the fuel supply pipe 38 is opened. The gas fuel is continuously supplied to the compressed air supply pipe 27.

  However, when the supercharging pressure in the combustion chamber 11 rises and exceeds the set pressure value, as shown in FIG. 2, high-pressure compressed air passes through the pressure take-out pipe 44 from the compressed air supply pipe 27 and flows into the valve cylinder 42. Since the gas is supplied from the upper end to the inside, the valve element 43 operates downward against the spring force of the push-up spring 45. As a result, the O-ring 46 of the valve body 43 moves to shut off the fuel supply pipe 38. For this reason, the gas fuel is not supplied to the compressed air supply pipe 27.

  As described above, when the supercharging pressure in the combustion chamber 11 exceeds a predetermined set pressure value, the relationship between the supply of compressed air for supercharging and the fuel supply is broken, that is, in the combustion chamber 11. If the supercharging pressure exceeds a predetermined set pressure value, the fuel supply control valve 41 operates to shut off the fuel supply even if the supply of compressed air for supercharging is continued. When the supercharging pressure in the combustion chamber 11 rises above the set pressure value, the fuel becomes lean, and an appropriate air-fuel ratio cannot be obtained. Or incomplete combustion, and excessive explosion energy is not generated by combustion at a high supercharging pressure that adversely affects the durability and safety of the nailer.

[Embodiment 2]
Next, another embodiment 2 of the present invention will be described with reference to FIG. In this embodiment, when the supercharging pressure in the combustion chamber 11 by the compressed air for supercharging supplied into the combustion chamber 11 exceeds a set pressure value, the combustion chamber 11 enters the striking cylinder 5. The present invention relates to a means for releasing the supercharging pressure.

  As described above, the gas fuel is supplied from the fuel supply device 19 (see FIG. 1) according to the supply amount of the compressed air supplied from the compressor 25, thereby ensuring an appropriate air-fuel ratio. Yes. The compressed air supply pipe 27 and the fuel supply pipe 38 are directly connected, and the injected fuel merges with the compressed air and is supplied from the compressed fuel supply pipe 39 into the combustion chamber 11. .

  By the way, the partitioning member 16 that partitions the lower part of the combustion chamber 11 and forms the inner space of the striking cylinder 5 between the upper part of the striking piston 6 at the top dead center includes the inner space of the striking cylinder 5 and the combustion chamber 11. The head valve 21 is provided which can communicate with the engine and can be disconnected. In the present embodiment, the head valve 21 has a supercharging pressure in the combustion chamber 11 that is a predetermined set pressure. In the state below the value, the head valve 21 is always moved up by the push-up force of the push-up spring 22 to close the supply port 20 of the striking cylinder 5 as shown in FIG. When the internal supercharging pressure exceeds the set pressure value, the head valve 21 moves downward against the push-up spring 22 to open the combustion chamber 11 to the supply port 20 as shown in FIG.

  Therefore, when the supercharging pressure in the combustion chamber 11 due to supercharging exceeds the set pressure value, the above-described head valve 21 moves down to open the combustion chamber 11 to the supply port 20 (see the figure), and is high in the impact cylinder 5 A supercharging pressure mixed gas flows through the opening of the head valve 21. For this reason, since the striking piston 6 is pushed down to the supercharging pressure, the volume of the combustion chamber 11 is substantially enlarged. In this way, since the excess supercharging pressure in the combustion chamber 11 is released to the internal space of the impact cylinder 5, the supercharging pressure in the combustion chamber 11 is reduced, and the explosion energy due to combustion is suppressed.

  In this way, when the supply port 20 is opened by the head valve 21, the mixed fuel with a high supercharging pressure, which is a mixed fuel, flows into the internal space of the striking cylinder 5, and the pressure in the internal space of the cylinder 5 increases due to the inflow of this fuel. Thus, the piston operates, but this pressure is lower than the pressure due to combustion, so it does not adversely affect the durability and safety of the nailer.

[Embodiment 3]
Next, another embodiment of the present invention will be described with reference to FIG.

  In this embodiment, the switch S for ignition is turned on by the electric circuit control of the control board 35 of the ignition control device by the detection signal of the pressure sensor 47 for detecting the pressure exceeding the set pressure value in the combustion chamber 11. It relates to means for preventing operation.

  As shown in the figure, a pressure sensor 47 is attached to the side wall of the combustion chamber 11, and when the supercharging pressure in the combustion chamber 11 exceeds a set pressure value, this pressure state is detected by the pressure sensor 47 and detected. A signal is emitted. When the transmitted detection signal is received, the signal is programmed so that the ignition switch S of the spark plug 12 of the electric circuit of the control board 35 of the ignition control device is not turned on.

  Therefore, even if the trigger 40 is pushed in and the switch S is turned ON, the operation is invalidated and the spark plug 12 is not ignited, and the mixed gas is not combusted in the combustion chamber 11.

[Embodiment 4]
In this embodiment, the contact member of the micro switch S that burns the mixed fuel in the combustion chamber 11 by igniting the spark plug 12 by the cylinder mechanism that operates according to the pressure exceeding the set pressure value in the combustion chamber. The present invention relates to a means for moving to a position not engaged with the trigger.

  That is, as shown in FIG. 6, the pressure take-out pipe 44 branched from the middle of the compressed air supply pipe 27 that supplies the compressed air from the compressor 25 into the combustion chamber 11 is a cylinder 48 of the cylinder mechanism 47. The supercharging pressure in the combustion chamber 11 acts directly in the cylinder 48 through the pressure take-out pipe 44. A piston 50 and a piston rod 51 are provided in the cylinder 48, and the tip of the piston rod 51 protrudes from the cylinder 48 and abuts on the front side surface of the microswitch S. The microswitch S is slidably arranged back and forth, and is urged so as to always move forward by a spring 52 arranged on the side surface thereof. The contact member 53 of the micro switch S is formed to protrude downward.

  On the other hand, the switch pressing portion 54 is disposed at the upper end of the trigger 40 so as to correspond to the contact member 53 of the micro switch S in the normal state.

  With the above configuration, if the supercharging pressure in the combustion chamber 11 is equal to or lower than the set pressure value, the microswitch S is normally urged forward by the spring 52, but as shown in FIG. When the internal supercharging pressure exceeds the set pressure value, when the piston rod 51 slides the micro switch S backward against the spring 52 together with the piston 50 in the cylinder 48 by the supercharging pressure, the contact member 53 triggers the trigger 40. Move to a position where it cannot be engaged. For this reason, even if the trigger 40 is pulled up, the contact member 53 cannot be pushed in, so the nailing machine cannot be started.

  Although a mechanical switch using a microswitch has been described here, the present invention is not limited to this, and an electrical switch using a Hall element or the like may be used.

  Although not shown, instead of moving the contact member of the microswitch to a position where it does not engage with the trigger, a piston rod of a cylinder mechanism that operates in response to a pressure exceeding the set pressure value in the combustion chamber is provided. You may comprise so that it may protrude and interfere in the middle of the movement locus | trajectory of the said trigger.

[Embodiment 5]
The supercharging pressure by the compressor 25 and the fuel injection amount by the fuel supply device are configured to work together until the supercharging pressure reaches a set pressure, but when the set pressure value is exceeded, the compressor The supercharging pressure by 25 and the fuel injection amount by the fuel supply device are set independently of each other, and are set separately from the fuel supply device including the gas fuel cartridge 13 shown in FIGS. Inject gas fuel.

  According to the above configuration, since the fuel injection amount is constant even when the supercharging pressure becomes higher than the set pressure value, it does not increase any more. For this reason, when only the supercharging pressure is increased, only the amount of air is increased compared to the fuel gas, and the mixed gas becomes lean. . Therefore, since it becomes lower than the set energy, the durability and safety of the nailer can be ensured.

5 Stroke cylinder 6 Stroke piston 8 Movable housing 11 Combustion chamber 19 Fuel supply device 25 Compressor 41 Fuel supply control valve

Claims (4)

A striking cylinder that slidably houses a striking piston, a combustion chamber that is openable and closable above the striking cylinder, a compressor that supplies compressed air for supercharging, and a fuel supply device that supplies fuel gas In a gas internal combustion nailer that mixes supercharged fuel gas and air and ignites and burns,
A gas internal combustion nail characterized by invalidating an operation of a trigger for performing ignition combustion when a supercharging pressure by compressed air for supercharging supplied into the combustion chamber exceeds a set pressure value Hammer.   The operation of the trigger is invalidated so that the ignition combustion switch is not turned on by electric circuit control of the ignition control device based on a detection signal of a pressure sensor that detects a pressure exceeding the set pressure value in the combustion chamber. The gas internal combustion nailing machine according to claim 1, wherein the gas internal combustion nailing machine according to claim 1 is realized. By igniting and burning a mixed gas of fuel gas and air supercharged in the combustion chamber by pressing a contact member of the switch for ignition combustion by operation of the trigger,
The invalidation of the operation of the trigger is realized by moving the contact member of the switch to a position not engaged with the trigger by a cylinder mechanism that operates according to a pressure exceeding the set pressure value in the combustion chamber. The gas internal combustion nailer according to claim 1, characterized in that: By igniting and burning a mixed gas of fuel gas and air supercharged in the combustion chamber by pressing a contact member of the switch for ignition combustion by operation of the trigger,
Invalidating the operation of the trigger is realized by moving a piston rod of a cylinder mechanism that operates in response to a pressure exceeding the set pressure value in the combustion chamber to a position that interferes with the trigger. The gas internal combustion nailer according to claim 1.

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