Fuel cartridge and gas-combustion type driving tool

A fuel cartridge, which is capable of being mounted on a tool main body of a gas-combustion type driving tool so as to supply fuel gas to a striking mechanism of the tool main body, is provided with an ejection nozzle provided at a port portion formed at an end portion of a cartridge main body and slidable with respect to the cartridge main body; a compression spring for biasing the ejection nozzle so that a tip end of the ejection nozzle protrudes from the cartridge main body; and an ejection hole formed at a side wall of a tip end portion of the ejection nozzle.

BACKGROUND OF THE INVENTION

1. <Field of the Invention>

The present invention relates to a fuel cartridge in which fuel gas is filled and also relates to a driving tool such as a gas-combustion type nailing machine which explosively combusts fuel gas supplied from the fuel cartridge to thereby drive a striking mechanism.

In a first example of the known coupling portion of a fuel cartridge to a machine main body, a passage communicating from a coupling portion to a fuel measuring device is formed on the machine main body side having the coupling portion for connecting the fuel cartridge so that fuel supplied from the fuel cartridge is supplied to the combustion chamber of the machine via the fuel measuring device. The fuel cartridge is coupled via the coupling portion in a manner that a male nozzle member having a nozzle opening at the center of a projection portion on the fuel cartridge side and a female nozzle member having a nozzle opening at the center of the projection portion at the lower portion of a solenoid on the machine main body side are pushed and inserted into a seal holder housing a seal member which is a coupling member capable of being held by a bush member at the lower portion of the solenoid (see a patent document 1, for example).

In a second example, an adaptor housing a seal member at the time of coupling is set on the nozzle side of a fuel cartridge, whereby the nozzle (fuel cell system) is protected from the outside by the adaptor. The fuel cartridge is attached in a manner that when the fuel cartridge disposed in a fuel cell chamber is pushed in toward one direction, lugs at the outer periphery of the nozzle engage with locking tangs of a latch disposed within the cell chamber. The fuel cartridge is detached in a manner that the locking tangs are disengaged from the lugs at the outer periphery of the nozzle by operating a push button for the latch (see a patent document 2, for example)[Patent Document 1] U.S. Pat. No. 6,217,085[Patent Document 2] JP-A-2002-192479

In the first example, in a state that the fuel cartridge is not coupled, the passage of the coupling portion on the machine main body side is opened and further the seal portion of the nozzle of the seal holder as the coupling member is also placed in an exposed state. Thus, dust etc. likely enters into these portions to thereby cause a trouble in the fuel measuring device and the seal portion of the nozzle. Further, since the male nozzle member pushed and inserted into the seal holder is firmly held by the sliding resistor at the seal portion, the nozzle member does not restore to the initial position by a returning load of the nozzle portion of the fuel cartridge at the time of detaching the fuel cartridge. Thus, since it is required to pull out the fuel cartridge at the time of detaching the fuel cartridge, the operability of the attachment/detachment of the cartridge is not good.

In the second example, since the adaptor has the complicated structure and also the structure for attaching/detaching the fuel cartridge is complicated, the attachment/detachment property of the cartridge is not good.

SUMMARY OF THE INVENTION

One or more embodiments of the invention provide a fuel cartridge and a gas-combustion type driving tool in which a fuel passage of the fuel cartridge is surely secured without causing a trouble, a structure of a port portion of the fuel cartridge is simple, and an attachment/detachment of the fuel cartridge with respect to a gas-combustion type driving tool can be simply and easily performed.

In accordance with one or more embodiments of the invention, a fuel cartridge, which is capable of being mounted on a tool main body of a gas-combustion type driving tool so as to supply fuel gas to a striking mechanism of the tool main body, is provided with: an ejection nozzle4provided at a port portion formed at an end portion of a cartridge main body1and slidable with respect to the cartridge main body1; a compression spring16for biasing the ejection nozzle4so that a tip end of the ejection nozzle4protrudes from the cartridge main body1; and an ejection hole17formed at a side wall of a tip end portion of the ejection nozzle4. The compression spring16biases the ejection nozzle4in an axial direction of the ejection nozzle4. A direction in which the ejection hole17extends intersects with the axial direction of the ejection nozzle4.

According to the above structure, the ejection nozzle is provided at the port portion formed at the end portion of the cartridge main body so as to be slidable freely, and the ejection nozzle is biased by the compression spring so that the tip end thereof always protrudes from the cartridge main body. Thus, since the ejection nozzle is arranged to move slidably against the biasing force of the spring when the cartridge is loaded into the tool main body of the gas-combustion type driving tool, the fuel gas within the fuel cartridge can be supplied to the tool main body simultaneous with the loading of the fuel cartridge.

In addition, since the ejection hole for the fuel gas is formed at the side wall of the tip end portion of the ejection nozzle, the ejection hole is not closed even if the tip end of the ejection nozzle is pushed against a floor etc., whereby residual gas can be exhausted efficiently. The ejection hole of the ejection nozzle may be closed at the tip end thereof or formed in a groove shape so long as the ejection hole is configured to be able to exhaust the fuel gas to the side direction of the ejection nozzle.

The fuel cartridge may further includes a valve11,15disposed at the port portion. The valve11,15may open when the ejection nozzle4slides against a biasing force of the spring16.

According to the above structure, the valve body is disposed at the port portion, and an opening/closing mechanism is opened when the ejection nozzle slides against the biasing force of the spring. Thus, the nozzle slides simultaneous with the loading of the fuel cartridge and so the fuel gas within the fuel cartridge can be supplied to the tool main body.

The fuel cartridge may further includes an adaptor sleeve18provided at a periphery of the ejection nozzle4.

According to the above structure, since the adaptor sleeve is provided at the periphery of the ejection nozzle in the main body of the cartridge, the ejection nozzle can be protected from an external force applied from the outside.

Tip end of the ejection nozzle4may protrude outward from an opening end of the adaptor sleeve18.

According to the above structure, the tip end of the ejection nozzle is provided so as to protrude outward from the opening end of the adaptor sleeve, when the tip end of the ejection nozzle4is pushed against a suitable member. Thus, since the ejection nozzle is pushed in by a length corresponding to the protruded length from the adaptor sleeve, the opening/closing mechanism can be opened, whereby the remained fuel gas can be exhausted from the ejection hole of the ejection nozzle

The fuel cartridge may further includes an inner plate20slidable within the adaptor sleeve18and having a fitting hole25which fits with the ejection nozzle4. The inner plate20may be biased in a direction of protruding to an outside of the adaptor sleeve18.

According to the above structure, since the inner plate having the fitting hole fitting to the ejection nozzle is provided at the opening end of the adaptor sleeve, the ejection nozzle can be held stably. Further, the seal portion of the opening/closing mechanism of the ejection nozzle can be protected from the outside and the adhesion of dust etc. can be protected. Furthermore, since the inner plate is provided so as to be slidable freely, the inner plate can be slid together with the ejection nozzle and the opening/closing operation of the opening/closing mechanism is not interfered by the sliding operation.

The fuel cartridge may further includes a guide portion26provided on the inner plate20and for guiding a coupling portion54in the tool main body34to the ejection nozzle4.

According to the above structure, since the inner plate is provided with the guide portion for guiding the coupling portion provided at the driving tool to the ejection nozzle, the ejection nozzle can be disposed correspondingly at a predetermined position of the coupling portion.

The inner plate20may be biased so as to protrude outward than an opening end of the adaptor sleeve18.

According to the above structure, the inner plate is biased by the spring so as to protrude outward than the opening end of the adaptor sleeve. Thus, the stable holding and the dust proof of the ejection nozzle can be performed more surely. Further, if the bias spring is arranged to be compressed when the cartridge is attached to the driving tool, the cartridge can be detached by using the biasing force of the bias spring in the case of detaching the cartridge after use.

The compression spring16, the inner plate20and the adaptor sleeve18may be disposed coaxially with the ejection nozzle4.

According to the above structure, since the compression spring, the inner plate and the adaptor sleeve are disposed coaxially with the ejection nozzle, the sliding of each of the ejection nozzle and the inner plate and the expansion/compression of the compression spring are directed in the same direction, whereby the entire mechanism can be configured simply.

The fuel cartridge may further include a cap30for covering the inner plate20and the ejection nozzle4and detachably attached to the adaptor sleeve18. The cap30may include a needle portion32capable of being inserted inside of the ejection nozzle4from a tip end of the ejection nozzle4at a center portion of an inside of the cap30. An inner diameter of the cap30may be slightly larger than an outer diameter of a bottom portion of the fuel cartridge.

According to the above structure, the cap for covering the inner plate and the ejection nozzle is provided at the adaptor sleeve so as to be detachable freely, the needle portion capable of being inserted inside of the ejection nozzle from the tip end thereof is formed at the center portion of the inside of the cap, and the inner diameter of the cap is set so as to be slightly larger than the outer diameter of the bottom portion of the fuel cartridge. Thus, in the case of exchanging the fuel cartridge, the cap of a new fuel cartridge is strongly pushed into and fit to the bottom portion of the old fuel cartridge, whereby the needle portion at the center portion breaks through the bottom portion of the old fuel cartridge to exhaust the compressed gas contained therein. Thus, the spent fuel cartridge can be disposed safely.

Moreover, in accordance with one or more embodiments of the invention, a gas-combustion type driving tool is provided with: a housing portion52capable of loading a fuel cartridge A from one end of the housing portion52, the fuel cartridge A including an ejection nozzle4biased by a first compression spring16and fuel gas being ejected when the ejection nozzle4is pushed with respect to a cartridge main body1against a biasing force of the first compression spring16; a coupling sleeve61provided at the other end of the housing portion52and capable of inserting the ejection nozzle4of the fuel cartridge therein; a nozzle piston62slidably housed with in the coupling sleeve61and capable of abutting a tip end of the ejection nozzle4; and a second compression spring70for biasing the nozzle piston62to a tip end portion side of the coupling sleeve61. A biasing force of the second compression spring70is smaller than the biasing force of the first compression spring16. After the fuel cartridge A is pushed into the housing portion52to move backward the nozzle piston62to a movable end thereof by the first compression spring16, when the fuel cartridge A is further pushed in, the nozzle piston62pushes in the ejection nozzle4so that the fuel gas is ejected from the ejection nozzle4and supplied to a side of the coupling sleeve61.

According to the above structure, the gas-combustion type driving tool includes the tubular housing portion capable of loading the fuel cartridge from one end thereof, the fuel cartridge is arranged in a manner that the ejection nozzle is provided at the end portion of the main body of the cartridge filled with the fuel gas so as to be slidable freely, the ejection nozzle is biased by the first compression spring so that the tip end thereof always protrudes from the cartridge main body, and the opening/closing mechanism is opened when the ejection nozzle is pushed in against the biasing force of the first compression spring to thereby eject the fuel gas from the ejection nozzle, wherein the coupling sleeve capable of inserting the ejection nozzle of the fuel cartridge therein is provided at the other end of the housing portion, the coupling sleeve houses therein the nozzle piston capable of abutting against the tip end of the ejection nozzle of the fuel cartridge loaded into the housing portion so as to be slidable freely, the nozzle piston is normally biased by the second compression spring so as to locate near the tip end portion of coupling sleeve, the biasing force of the first compression spring is set to be larger than the biasing force of the second compression spring, and after the fuel cartridge is pushed into the housing portion to move backward the nozzle piston to the movable end thereof by the first compression spring, when the fuel cartridge is further pushed in, the nozzle piston pushes in the ejection nozzle to open the opening/closing mechanism, whereby the fuel gas is ejected from the ejection nozzle and supplied to the coupling sleeve side. Thus, in the case where the cartridge is pushed and loaded in the housing portion, the opening/closing mechanism of the fuel cartridge is simultaneously opened, whereby the fuel gas is ejected from the ejection nozzle and supplied to the coupling sleeve side. Therefore, the fuel passage of the fuel gas from the ejection nozzle is secured and so the driving tool can be operated surely. Further, since the structure of the port portion of the fuel cartridge is simple, the cartridge can be attached to and detached from the driving tool easily and simply.

A tip end of the nozzle piston62in an axial direction of the nozzle piston may be closed. The nozzle piston62may include an introduction hole67extending in a direction intersecting said axial direction and formed near the tip end portion. Two seal members65,66may be provided at an inner peripheral surface of the coupling sleeve61with an interval therebetween. When an ejection hole17of the ejection nozzle4extending in a direction intersecting said axial direction and the introduction hole67are located between the seal members65,66, the fuel gas may be supplied from the ejection hole17to the introduction hole67.

According to the above structure, the tip end of the nozzle piston is closed, the introduction hole is formed at the side wall near the tip end portion, the ejection hole is formed at the side wall near the tip end portion of the ejection nozzle, two seal members are provided so as to have the interval therebetween at the inner peripheral surface of the coupling sleeve, and when the ejection hole and the introduction hole are located between these seal members, the fuel passage is formed from the fuel cartridge to the coupling sleeve side between the inner peripheral surface of the coupling sleeve and the outer peripheral surfaces of the tip ends of the nozzle piston and the ejection nozzle. Thus, the fuel gas can be supplied to the nozzle piston from the ejection nozzle.

A tip end of the nozzle piston62in an axial direction of the nozzle piston may be closed. Two seal members65,66may be provided at an inner peripheral surface of the coupling sleeve61with an interval therebetween. An introduction hole67penetrating a side wall of the coupling sleeve61may be formed between the seal members65,66. When an ejection hole17of the ejection nozzle4extending in a direction intersecting said axial direction are located between the seal members65,66, the fuel gas may be supplied from the ejection hole17to the introduction hole67.

According to the above structure, in place of the nozzle piston, the introduction hole is formed in a penetrated manner at the side wall of the coupling sleeve between the two seal members. Thus, the fuel passage is not limited to the coupling sleeve and may be designed freely.

The tool main body34may be provided with a fuel measuring device50.

According to the above structure, the tool main body is provided with the fuel measuring device communicating with the fuel passage. Thus, since it is not necessary to provide the fuel measuring device at the fuel cartridge, the cost of the fuel cartridge can be reduced.

The cartridge main body1may be provided with an adaptor sleeve18at a periphery of the ejection nozzle4. An inner plate20having a fitting hole25fitting to the ejection nozzle4may be slidably provided within the adaptor sleeve18. The inner plate20may be biased in a direction of protruding toward an outside of the adaptor sleeve18.

According to the above structure, when the fuel gas within the fuel cartridge is consumed completely, the housing portion is opened. Thus, the bias spring having been compressed by the inner plate is released and also both the first compression spring and the second compression spring are released, whereby the fuel cartridge is pushed out backward by the restoring force of these springs. As a result, the fuel cartridge can be detached easily.

A dust proof seal member64which contacts with the nozzle piston62in a standby state to prevent dust from entering from an end portion of the coupling sleeve61may be provided at an inner peripheral surface of the end portion of the coupling sleeve61.

According to the above structure, the dust proof seal member, which contacts with the nozzle piston in the standby state to prevent dust from entering from the end portion of the coupling sleeve, is provided at the inner peripheral surface of the end portion of the coupling sleeve. Thus, even in a state the fuel cartridge is not coupled, dust is prevented from entering into the coupling sleeve. Further, even in a state where the fuel cartridge is coupled, since the seal member contacts with the ejection nozzle, dust can be effectively prevented from entering into the coupling sleeve from the outside.

DESCRIPTION OF THE REFERENCE NUMERALS AND SIGNS

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Exemplary embodiments of the invention is described in reference to drawings. InFIGS. 1 and 2, a sign A denotes a cartridge A. The cartridge A is provided so as to be freely attachable to and detachable from a gas-combustion type driving tool described later to thereby supply fuel gas to the striking mechanism of the tool main body. The fuel cartridge is configured by a cartridge main body1, an inner bag2disposed within the cartridge main body1and an opening/closing mechanism3for ejecting fuel gas filled within the inner bag2, etc.

Liquid fuel gas G1is filled within the inner bag2and compressed gas G2pressurized so as to be higher than the pressure of the liquid fuel gas G1is filled in a space S between the cartridge main body and1and the inner bag2. The compressed gas G2acts to press the surface of the inner bag2to crush the inner bag2to thereby eject the liquid fuel gas G1to the outside from an ejection nozzle4. Normally propellant gas is filled as the compressed gas. In this manner, the pressure of the propellant gas within the cartridge1is set to be higher than the inner pressure of the inner bag2by two or three atmospheric pressures so that the inner bag2is pressed by the gas pressure of the propellant gas to thereby eject the fuel gas.

The cartridge main body1is configured by a cylindrical member made of aluminum and having a predetermined diameter, a predetermined length and a predetermined thickness. An end wall1afor filling the liquid fuel gas is formed at the tip end opening portion of the cartridge main body. A bottom portion1bis caved in a conical manner and an opening portion5for filling the compressed gas is formed at the center portion of the caved portion. The opening portion is closed by a rubber plug6. In contrast, since the inner bag2is disposed within the cartridge main body1, the inner bag has an outer shape similar to that of the cartridge main body1in a state that the gas to be filled therein is not yet filled. Further, the inner bag is smaller than the cartridge main body1and is formed by a cylindrical member having a bottom portion and formed by a thin aluminum etc. which is likely deformed.

Further, an annular expanded projection portion7is formed at the tip end portion of the cartridge main body1. The end wall1ais provided near the expanded projection portion. A short tubular portion8is formed at the center portion of the end wall1aso as to protrude outward. The tip end of the short tubular portion8is bent inside so as to be have a small diameter and is provided with a port portion10having a diameter smaller than the inner diameter of the short tubular portion8. At the inside of the short tubular portion8, the opening/closing mechanism3for opening/closing the inner bag2and the ejection nozzle4is provided by a seal portion11and the ejection nozzle4.

The seal portion11is formed by composite resin in an annular shape and fixed to the bottom portion of the short tubular portion8. The ejection nozzle4is provided at the port10so as to be slidable freely. The ejection nozzle4is also made by composite resin. An end portion12on the outer side of the ejection nozzle is opened and an end portion13on the inner side of the ejection nozzle is closed. A spring receiving seat14is formed near the end portion13on the inner side of the ejection nozzle4. A hole15is formed in a penetrated manner on the end portion side of the spring receiving seat14.9denotes a spring bearing. A first compression spring16is disposed between the spring bearing9and the hole15, whereby the ejection nozzle4is always biased so as to protrude outward. When the ejection nozzle4is in a standby state, the hole15is closed by the seal portion11. When the ejection nozzle4is pushed inside as shown by an arrow inFIG. 3against the first compression spring16, since the hole15moves away from the seal portion11, the opening/closing mechanism3is opened.

A supply hole17for ejecting the fuel gas within the ejection nozzle4to the outside is formed in a penetrated manner near the end portion on the outer side of the ejection nozzle4.

Further, an adaptor sleeve18is attached to the tip end portion of the cartridge main body1and an inner plate20is provided at the tip end of the adaptor sleeve18so as to be slidable freely.

The adaptor sleeve18is formed by composite resin in a tubular shape. An annular recess portion21is formed at the outer peripheral surface of the base portion of the adapter sleeve so as to be able to fit to the inside of the expanded projection portion7at the tip end of the cartridge main body1. Thus, the adaptor sleeve18can be attached by being strongly pushed into the inside of the portion of the cartridge main body1. Further, a flange portion22is formed near the annular recess portion21and a plurality of ribs23are formed with an interval thereamong on the outer side of the flange portion22. A diameter of a circle formed by coupling the outer side surfaces of these ribs23is formed so as to be almost same as the diameter of the cartridge main body1. Furthermore, an engagement edge24having an end portion bent inside so as to have a small diameter is formed at the tip end of the adaptor sleeve18. The tip end of the ejection nozzle4is provided so as to protrude outward than the opening end of the adaptor sleeve18.

The inner plate20is fit to the inside of the adaptor sleeve18so as to be slidable freely and is provided with a fitting hole25for the ejection nozzle4at the center portion thereof. Further, guide projections (guide portions)26are provided at the outer side of the fitting hole25in an annular manner with an interval thereamong. In the standby mode, the inner plate20engages with the engagement edge24of the adaptor sleeve18in a manner that a protrusion edge28formed at the outer peripheral end of the inner plate engages with the engagement edge of the adaptor sleeve by a bias spring27provided between the inner plate and the end wall1aof the port portion of the cartridge main body1.

The ejection nozzle4, the first compression spring16, the bias spring27, the inner plate20and the adaptor sleeve18are disposed on the same axis.

Further, a cap30is provided at the adaptor sleeve18so as to be detachable freely. The cap30acts to cover the inner plate20and the ejection nozzle4to thereby protect these members from an external force and dust and prevent the fuel gas from being erroneously ejected. The inner diameter of the cap30is set so as to be slightly larger than the outer diameter of the bottom portion of the fuel cartridge A. An engagement groove31capable of engaging with the flange portion22of the adaptor sleeve18is formed at the inner peripheral surface of the opening end portion of the cap30. A needle portion32capable of being inserted inside of the ejection nozzle4from the tip end thereof is formed at the center portion of the inside of the cap30.

According to the aforesaid configuration of the fuel cartridge, the ejection nozzle4is provided so as to be slidable freely at the port portion formed at the end portion of the cartridge main body1, the first compression spring16biases the ejection nozzle so that the tip end of the ejection nozzle4always protrudes from the cartridge main body1, the valve body is disposed at the port portion, and the opening/closing mechanism3is operated to be opened when the ejection nozzle4is slid against the biasing force of the spring. In this manner, since the fuel cartridge is configured in a manner that when the fuel cartridge is attached to the tool main body of the gas-combustion type driving tool, the ejection nozzle4is slid against the biasing force of the first compression spring16, the fuel gas within the fuel cartridge A can be supplied to the tool main body simultaneously with the attachment of the fuel cartridge A.

Further, since the cartridge main body1is provided with the adaptor sleeve18at the outer periphery of the ejection nozzle4, the ejection nozzle4can be protected from the external force applied from the periphery.

Further, the tip end of the ejection nozzle4is provided so as to protrude outward than the opening end of the adaptor sleeve18. Thus, when the tip end of the ejection nozzle4is pushed against a suitable member, since the ejection nozzle4is pushed in by a length corresponding to the protruded length from the adaptor sleeve18, the opening/closing mechanism3can be opened, whereby the fuel gas remained within the inner bag can be exhausted from the supply hole17of the ejection nozzle4. Since the supply hole17is formed so as to penetrate the side wall of the tip end portion of the ejection nozzle4, as shown inFIG. 3, since the supply hole17is not closed when the tip end of the nozzle is pushed against a floor etc., the remaining gas can be exhausted efficiently.

In this manner, the supply hole17of the ejection nozzle4is sufficient so long as it has a structure capable of exhausting the fuel gas at the side direction of the ejection nozzle4. Thus, the tip end of the supply hole may be closed as shown inFIG. 4or the supply hole may be formed in a groove shape as shown inFIGS. 5(a),5(b) and5(c).

Further, since the inner plate20having the fitting hole25fitting with the ejection nozzle4is provided at the opening end of the adaptor sleeve18, the ejection nozzle4can be held stably. Further, the seal portion11of the opening/closing mechanism3of the ejection nozzle4can be protected from the outside and also the adhesion of dust can be prevented. Furthermore, since the inner plate20is provided so as to be slidable freely, the inner plate can be slid together with the ejection nozzle4, so that the opening/closing operation of the opening/closing mechanism3is not interfered.

Sine the inner plate20is equipped with the guide portion26for guiding the coupling portion provided at the driving tool to the ejection nozzle4, the ejection nozzle4can be correspondingly disposed at the predetermined position of the coupling portion.

Since the first compression spring16, the bias spring27, the inner plate20and the adaptor sleeve18are disposed on the coaxial line of the ejection nozzle4, the sliding of each of the ejection nozzle4and the inner plate20and the expansion/compression of each of the first compression spring16and the bias spring27are directed in the same direction, whereby the entire mechanism can be configured simply.

Further, the cap30for covering the inner plate20and the ejection nozzle4is provided at the adaptor sleeve18so as to be detachable freely. The needle portion32capable of being inserted inside of the ejection nozzle4from the tip end thereof is formed at the center portion of the inside of the cap30and the inner diameter of the cap30is formed so as to be slightly larger than the outer diameter of the bottom portion of the fuel cartridge A, the cartridge can be protected from the external force and the dust and the fuel gas is prevented from being ejected erroneously. Further, since the needle portion32is inserted into the ejection nozzle4, the ejection nozzle4can be held in the stable state. Furthermore, in the case of exchanging the fuel cartridge A, as shown inFIG. 6, the cap30of a new fuel cartridge A is strongly pushed into and fit to the bottom portion of the cartridge main body1of the old fuel cartridge A, whereby the needle portion32at the center portion breaks through the bottom portion of the old fuel cartridge A to exhaust the compressed gas contained therein. Thus, the spent fuel cartridge A can be disposed safely.

Next, the explanation will be made as to a mechanism for attaching the fuel cartridge A to the gas-combustion type driving tool.

InFIG. 7, a sign B shows the driving tool (nailing machine) and34denotes the tool main body. A grip35and a magazine36are coupled to the tool main body34, and a combustion chamber37and a striking mechanism are provided within the tool main body. A nose portion38for driving a nail out is provided beneath the tool main body34, and the magazine36for supplying nails is coupled to the nose portion38.

The striking mechanism is configured in a manner that a striking piston42is housed within a striking cylinder41so as to be slidable freely and a driver43is integrally coupled to the striking piston42so as to extend beneath the piston.

A cylinder head portion44is provided with an ignition plug (not shown), a rotary fan46and a fuel injection nozzle45. The ignition plug ignites mixed gas of the fuel gas and the air within the combustion chamber37to combust the mixed gas. The rotary fan46acts to stir and mix the fuel gas and the air and is disposed at the center of a movable sleeve47.

48denotes a motor for driving the rotary fan46.

The movable sleeve47constituting the combustion chamber37is disposed at the outer upper portion of the striking cylinder41. The movable sleeve47is configured in a cylindrical shape and is disposed between the striking cylinder41and the cylinder head portion44formed within the upper housing so as to be slidable elevationally. The combustion chamber37in a sealed state is formed within the movable sleeve47when the movable sleeve moves upward, whilst the combustion chamber37is opened when the movable sleeve moves downward.

The movable sleeve47is coupled via a not-shown link member with a contact member51provided at the tip end of the nose portion38so as to be slidable freely. The contact member51is biased by a spring so as to protrude from the tip end of the nose portion38. Thus, when the nose portion38is pressed against the material to be struck, since the contact member51is pushed in and moves upward, the movable sleeve47also moves upward via the link member to thereby constitute the sealed combustion chamber37. In contrast, when the nose portion38is separated from the material to be struck, since the contact member51moves to the original position, the movable sleeve47also moves downward to thereby open the combustion chamber37.

Thus, when the fuel gas is supplied to the combustion chamber37in the sealed state from the fuel measuring device described later and the mixed gas of the fuel gas and the air is stirred and ignited to combust the mixed gas, the striking piston of the striking mechanism is driven, whereby a nail supplied within the nose portion38is driven out.

Next, a housing portion52capable of loading the fuel cartridge A therein is formed at the upper portion of the magazine36. The housing portion52is formed in a cylindrical shape.

A lock member53is provided at the rear end portion of the housing portion and a coupling portion54to be coupled with the fuel cartridge A is provided at the front end side of the housing portion. Further, the coupling portion54is coupled via a fuel supply tube55to a fuel measuring device50provided at the upper portion of the tool main body34. The fuel measuring device50supplies a constant amount of the fuel gas to the fuel injection nozzle45via another fuel supply tube50a.A known fuel measuring device may be employed.

As shown inFIGS. 7 to 9, the lock member53is configured in a manner that a coupling piece57is formed so as to have a size capable of closing the rear end of the housing portion52and be coupled to the housing portion52from a part of a plate member56, engagement projection pieces58are protrusively formed at the both sides of the coupling piece57, and the coupling piece57is coupled to a long hole59formed at the rear end portion of the housing portion52so as to be able to open/close the hole and also so as to be slidable.

The engagement projection pieces58are formed so as to be able to elastically engage with engagement grooves60formed at the both side portions of the rear end of the housing portion52, respectively.

Next, as shown inFIG. 10, the coupling portion54is provided with a coupling sleeve61which rear end is opened to the fuel supply tube55. A nozzle piston62is housed within the coupling sleeve61so as to be slidable freely. The coupling sleeve61is configured to have a size capable of being fit into the guide projection26of the inner plate20of the fuel cartridge A and is provided with an exhaust hole63at the tip end thereof. A first seal member64is provided on the inner peripheral surface of the coupling sleeve61between the tip end thereof and the exhaust hole63. Further, a second seal member65and a third seal member66are provided with a certain space therebetween between the base portion of the coupling sleeve and the exhaust hole63.

The nozzle piston62is configured in a manner that the shape thereof is a cylindrical shape having the same diameter as the ejection nozzle4, the tip end thereof is closed, the rear end is opened, and an introduction hole67for the fuel gas is formed at the side wall near the tip end portion thereof.

An annular projection edge68is formed at the rear portion of the nozzle piston62. The nozzle piston62is always biased by a second compression spring70disposed between the projection edge68and the bottom portion of the coupling sleeve61so as to locate near the tip end portion of the coupling sleeve61or protrude therefrom. The biasing force of the second compression spring70is smaller than the first compression spring16for biasing the ejection nozzle4within the fuel cartridge A.

When the nozzle piston is in the standby state, since the introduction hole67locates at the position matching with the exhaust hole63of the coupling sleeve61, the fuel gas remained within the fuel supply tube55of the tool main body34is emitted to the atmosphere from the exhaust hole63.

The ejection nozzle4and the nozzle piston62are configured so as to be aligned almost coaxially when the fuel cartridge A is loaded into the housing portion52.

In the aforesaid configurations when the fuel cartridge A from which the cap30is detached is inserted and pushed into the rear end of the housing portion52, as shown inFIG. 11, the coupling sleeve61is guided along and fit into the inner side of the projections26of the inner plate20, whereby the tip end of the ejection nozzle4abuts against the nozzle piston62. The biasing force of the first compression spring16for biasing the ejection nozzle4is larger than the biasing force of the second compression spring70for biasing the nozzle piston62. Thus, as shown inFIG. 12, since the nozzle piston62is pushed in against the second compression spring70as the fuel cartridge A is pushed in, the ejection nozzle4proceeds into the coupling sleeve from the opening end of the coupling sleeve61and finally the nozzle piston62abuts against the bottom portion of the coupling sleeve61. In this case, since the supply hole17of the ejection nozzle4and the induction hole67of the nozzle piston62are located between the second seal member65and the third seal member66of the coupling plate, a fuel passage69communicating with the fuel measuring device50is formed between the inner peripheral surface of the coupling sleeve61and the outer peripheral surfaces of the tip ends of the nozzle piston62and the ejection nozzle4. The inner plate20is also pushed into the inside of the adaptor sleeve18.

Further, when the fuel cartridge A is pushed in completely, as shown inFIG. 13, since the nozzle piston62is not pushed in any more, the ejection nozzle4is pushed in against the first compression spring16and moves backward. Thus, since the hole15of the ejection nozzle4is separated from the inner surface of the annular portion of the seal portion11, the opening/closing mechanism3opens. As a result, the fuel within the inner bag2is supplied to the fuel measuring device50from the hole15via the inner space of the ejection nozzle4, the supply hole17, the fuel passage, the inner space of the nozzle piston62and the fuel supply tube55.

After sufficiently pushing the fuel cartridge A into the housing potion52, as shown inFIG. 7, the lock member53is rotated to elastically engage the engagement piece thereof with the engagement grooves60of the housing portion52. As a result, the fuel cartridge A is always held in a state of supplying the fuel gas to the fuel measuring device5.

When the fuel gas within the fuel cartridge A is consumed completely, the lock member53is rotated downward to release the engagement state to thereby open the housing portion52. Thus, since the inner plate20is pushed in, the bias spring27having been compressed is released and also both the first compression spring16and the second compression spring70are released, whereby the fuel cartridge A is pushed out backward by the restoring force of these springs. As a result, the fuel cartridge A can be detached easily. The sum of the spring load of the bias spring27of the inner plate20and the spring load of the second compression spring70is set to be larger than the sliding resistance value between the ejection nozzle4and the seal members64and65of the coupling sleeve61.

In the case of exchanging the fuel cartridge A, the cap30of a new fuel cartridge A is strongly pushed into and fit to the bottom portion of the old fuel cartridge A, whereby the needle portion32at the center portion breaks through the bottom portion of the old fuel cartridge A to exhaust the compressed gas contained therein. Thus, the spent fuel cartridge can be disposed safely.

According to the aforesaid configuration, the opening/closing mechanism3of the fuel cartridge A can be opened simultaneously with the pushing and loading of the fuel cartridge A into the housing portion52, then the fuel gas can be ejected from the ejection nozzle4and supplied to the coupling sleeve61, and further the fuel gas can always be supplied to the fuel measuring device50from the coupling sleeve61. Thus, a predetermined amount of the fuel gas measured by the fuel measuring device50is supplied to the combustion chamber, then ignited and combusted, whereby the striking mechanism is driven.

Further, the tip end of the nozzle piston62is closed to form the introduction hole67at the side wall near the tip end portion, and the supply hole17is formed at the side wall near the tip end portion of the ejection nozzle4. Further, the second and third seal members65,66are provided at the inner peripheral surface of the coupling sleeve61with the interval therebetween. When the supply hole17and the introduction hole67are located between these seal members65,66, the fuel passage is formed from the fuel cartridge A to the coupling sleeve61side between the inner peripheral surface of the coupling sleeve61and the outer peripheral surfaces of the tip ends of the nozzle piston62and the ejection nozzle4, whereby the fuel gas can be supplied to the nozzle piston62from the ejection nozzle4.

Furthermore, since the fuel measuring device50communicating with the fuel passage is provided at the tool main body34, it is not necessary to the fuel measuring device50at the fuel cartridge A, so that the cost of the fuel cartridge A can be reduced.

Further, since the first seal member64, which contacts with the nozzle piston62in the standby mode to prevent dust from entering from the end portion, is provided at the inner peripheral surface of the opening end portion of the coupling sleeve61, dust can be prevented from entering into the coupling sleeve61even in the state that the fuel cartridge A is not coupled. Furthermore, even in the state that the fuel cartridge A is coupled, since the first seal member64contacts with the ejection nozzle4, dust from the outside can be effectively prevented from entering.

In place of the nozzle piston62, as shown inFIG. 14, the introduction hole67may be formed at the side wall of the coupling sleeve61between the two seal members65and66. According to this configuration, the fuel passage69is not limited to the coupling sleeve61and may be designed freely.

Further, the ejection nozzle4may not be formed integrally. As shown inFIG. 15, the ejection nozzle4may be configured by serially coupling a first ejection nozzle4aand a second ejection nozzle4b. According to this configuration, when the first ejection nozzle4ais short, the stroke of the first compression spring16can be secured additionally by an amount corresponding to the shortage of the first ejection nozzle.

Further, as shown inFIG. 16, the ejection nozzle4may be configured by the first ejection nozzle4aon the inner side and an auxiliary ejection nozzle4con the outer side in a manner that the auxiliary ejection nozzle4cis provided at the coupling sleeve61so as to slidable freely. An outer tube71freely fitting to the outside of the coupling sleeve61is integrally formed on the outside of the auxiliary ejection nozzle4c. The supply hole17is formed at the side wall of the end portion on the nozzle piston62side of the auxiliary ejection nozzle4cand the other portion of the auxiliary ejection nozzle is formed so as to be able to fit to the guide projection26of the inner plate20.

Also according to the aforesaid configuration, when the fuel cartridge A is loaded, after the second ejection nozzle4bpushes in the nozzle piston62together with the first ejection nozzle4a, the nozzle piston62pushes back to open the opening/closing mechanism3, whereby the ejection nozzle4can supply the fuel gas to the fuel passage. The second ejection nozzle4bcan reduce shock caused at the time of loading the fuel cartridge A.

While description has been made in connection with specific exemplary embodiment of the invention, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the present invention. It is aimed, therefore, to cover in the appended claims all such changes and modifications falling within the true spirit and scope of the present invention.