Patent Description:
The present invention relates to fastener driving tools specifically, to a combustion powered fastener driving tool, according to the preamble of claim <NUM>, with improved dosing levers. The present invention also relates to a fastener driving tool dosing lever according to the preamble of claim <NUM>. Such a combustion powered fastener driving tool and such a fastener driving tool dosing lever are known from <CIT>.

Powered fastener driving tools use one of several types of power sources to carry out a fastener driving cycle to drive a fastener (such as a nail or a staple) into a workpiece. More specifically, a powered fastener driving tool uses a power source to force a driving assembly, such as a piston carrying a driver blade, through a cylinder from a pre-firing position to a firing position. As the driving assembly moves to the firing position, the driver blade travels through a nosepiece, which guides the driver blade to contact a fastener housed in the nosepiece. Continued movement of the driving assembly through the cylinder toward the firing position forces the driver blade to drive the fastener from the nosepiece into the workpiece. The driving assembly is then forced back to the pre-firing position in a way that depends on the tool's construction and power source. A fastener advancing device forces another fastener from a magazine into the nosepiece, and the tool is ready to fire again.

Combustion powered fastener driving tools are one type of powered fastener driving tools that use a small internal combustion assembly as their power source. To operate various known combustion powered fastener driving tools, an operator depresses a workpiece contact element of the tool onto a workpiece. This moves the workpiece contact element from an extended position to a retracted position, which causes one or more mechanical linkages to cause: (<NUM>) a valve sleeve to move to a sealed position to seal a combustion chamber that is in fluid communication with the cylinder; and (<NUM>) a fuel supply assembly to dispense fuel from a fuel cell into the (now sealed) combustion chamber.

The operator then pulls the trigger to actuate a trigger switch, thereby causing a spark generator to deliver a spark and ignite the fuel/air mixture in the combustion chamber to start the fastener driving cycle. This generates high-pressure combustion gases that expand and act on the piston to force the driving assembly to move through the cylinder from the pre-firing position to the firing position, thereby causing the driver blade to contact a fastener housed in the nosepiece and drive the fastener from the nosepiece into the workpiece.

The fuel supply assembly is configured to dispense only a desired amount of fuel to the combustion chamber for each combustion event. The amount of fuel needs to be carefully monitored to provide the desired combustion in a fuel efficient manner to prolong the working life of the fuel cell. Accordingly, various combustion powered fastener driving tools include a fuel supply assembly including a dosing lever that engages with certain other components of the fuel supply assembly and the tool before each combustion cycle to dispense the desired dose of fuel from the fuel cell. Prior patent document <CIT> describes a combustion powered fastener driving tool including a fuel cell receiver configured to receive and engage a fuel cell metering valve of a fuel cell, the fuel cell metering valve configured to dispense a dose of fuel from the fuel cell.

Actuation of the tool causes the dosing lever to engage with certain other components of the tool and the fuel supply assembly to dispense the desired dose of fuel for the next combustion cycle. Certain known fuel supply assemblies of combustion powered fastener driving tools include dosing levers that can, in some circumstances, cause inconsistent amounts of fuel to be dispensed by the fuel supply assembly. For example, when certain known combustion powered fastener driving tools are actuated in relatively cold weather, the dosing lever can get stuck in an undesired position or otherwise cause undesirable engagement with one or more other components of the tool such that the fuel supply assembly dispenses inconsistent doses of fuel. There is a need for a combustion powered fastener driving tool with a fuel supply assembly that provides more consistent and stable doses of fuel in such circumstances.

Various embodiments of the present disclosure provide a dosing lever for a combustion powered fastener driving tool that solves the above problems in part by eliminating or reducing the likelihood of causing inconsistent amounts of fuel to be dispensed by the fuel supply assembly.

In various example embodiments of the present disclosure, the fastener driving tool includes a housing, a fastener driving assembly at least partially positioned in, connected to, and supported by the housing, a handle assembly connected to the housing, a fastener magazine assembly connected to the housing and the handle assembly, a workpiece contact assembly connected to the housing, and a fuel supply assembly at least partially positioned in, supported by, and connected to the housing. The fuel supply assembly includes a dosing lever that is configured, shaped, and sized to be better engaged by a combustion chamber ring during actuation of the dosing lever and dispensing of fuel for combustion of the fastener driving tool.

Other objects, features, and advantages of the present disclosure will be apparent from the following detailed disclosure and accompanying drawings.

While the systems, devices, and methods described herein may be embodied in various forms, the drawings show, and the specification describes certain exemplary and non-limiting embodiments. Not all of the components shown in the drawings and described in the specification may be required, and certain implementations may include additional, different, or fewer components. Variations in the arrangement and type of the components; the shapes, sizes, and materials of the components; and the manners of connections of the components may be made without departing from the spirit or scope of the claims. Unless otherwise indicated, any directions referred to in the specification reflect the orientations of the components shown in the corresponding drawings and do not limit the scope of the present disclosure. Further, terms that refer to mounting methods, such as mounted, connected, etc., are not intended to be limited to direct mounting methods but should be interpreted broadly to include indirect and operably mounted, connected, and like mounting methods. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the present disclosure and as understood by one of ordinary skill in the art.

For a better understanding of the present disclosure, an example known combustion powered fastener driving tool is first partially described. <FIG>, <FIG>, <FIG> illustrate an example known combustion powered fastener driving tool <NUM> (that is sometimes referred to herein as "known tool" for brevity). <FIG>, <FIG>, <FIG> show selected components of the example known tool <NUM> including: (<NUM>) a housing <NUM>; (<NUM>) a fastener driving assembly <NUM> partially positioned in, supported by, and connected to the housing <NUM>; and (<NUM>) a fuel supply assembly <NUM> partially positioned in, supported by, and connected to the housing <NUM>.

In the illustrated known fastener driving tool <NUM>, the fastener driving assembly <NUM> includes, in part: (<NUM>) a cylinder head <NUM>; (<NUM>) a combustion chamber <NUM> suitably connected to the cylinder head <NUM>; (<NUM>) a fan motor <NUM> suitably mounted to the cylinder head <NUM> and projecting into the combustion chamber <NUM>; (<NUM>) a sleeve <NUM> suitably connected to the combustion chamber <NUM>; and (<NUM>) a combustion chamber ring <NUM> suitably connected to an upper portion of the combustion chamber <NUM> and the cylinder head <NUM>.

In the illustrated known fastener driving tool <NUM>, the fuel supply assembly <NUM> includes, in part: (<NUM>) a fuel cell door <NUM> pivotally connected to the housing <NUM>; (<NUM>) a fuel cell <NUM> receivable in and at least partially supported by the housing <NUM>; (<NUM>) a fuel cell adapter <NUM> suitably connected to the fuel cell <NUM>; (<NUM>) a fuel cell metering valve <NUM> connected to the fuel cell adapter <NUM> and extending into a portion of the fuel cell <NUM>; (<NUM>) a fuel cell receiving block <NUM> mounted on, connected to, and in fluid communication with the fuel cell adapter <NUM>; (<NUM>) a fuel line <NUM> suitably connected between the fuel cell receiving block <NUM> and the cylinder head <NUM> to define a fuel pathway between the fuel cell <NUM> and the combustion chamber <NUM>; and (<NUM>) a dosing lever <NUM> pivotally supported by the cylinder head <NUM> and engaged to the fuel cell receiving block <NUM>. The fuel cell <NUM> and the adapter <NUM> are described as part of the fuel supply assembly for ease of description but are separate components receivable by the tool <NUM>.

In the illustrated known fastener driving tool <NUM>, the dosing lever <NUM> includes: (<NUM>) a dosing lever body <NUM>; (<NUM>) a first dosing lever leg <NUM> connected to and extending from a first end of the dosing lever body <NUM>; (<NUM>) a second dosing lever leg <NUM> connected to and extending from a second end of the dosing lever body <NUM>; (<NUM>) a first lever pivot <NUM> pin connected to and extending from the first dosing lever leg <NUM>; and (<NUM>) a second lever pivot <NUM> pin connected to and extending from the second dosing lever leg <NUM>.

In the illustrated known tool <NUM>, the first dosing lever leg <NUM> includes a foot <NUM> that includes: (<NUM>) a toe <NUM>; (<NUM>) a heel <NUM>; and (<NUM>) a sole <NUM> extending between and connected to the toe <NUM> and the heel <NUM>. The sole <NUM> defines a first contact surface <NUM> and the toe <NUM> defines a second contact surface <NUM>. In the known tool <NUM>, the second contact surface <NUM> has a completely curved and arcuate profile (having a radius of curvature of about <NUM> inches (<NUM> cms)) configured to engage one of the ring fingers <NUM> of the combustion chamber ring <NUM>. This engagement between the ring fingers <NUM> of the combustion chamber ring <NUM> and the foot <NUM> causes an actuation of the known dosing lever <NUM>. For brevity, only the foot <NUM> of the first dosing lever leg <NUM> is described herein; however, it will be understood that the second dosing lever leg <NUM> includes a foot <NUM> that is substantially identical to the foot <NUM>.

In certain circumstances, actuation of the known dosing lever <NUM> can cause the curved and arcuate profile of the second contact surface <NUM> of the foot <NUM> to temporarily stick to the ring fingers <NUM> of the combustion chamber ring <NUM>. In certain circumstances, this sticking between the known dosing lever <NUM> and the combustion chamber ring <NUM> can cause the fuel supply assembly <NUM> to dispense an improper amount of fuel to the fastener driving assembly <NUM>. As a result, the improper amount of fuel delivered to the fastener driving assembly <NUM> can cause variation in the combustion and operation of the known fastener driving tool <NUM>. The apparatus of the present disclosure overcomes these problems.

In the illustrated known fastener driving tool <NUM>, the dosing lever body <NUM> includes a fuel cell door facing section <NUM> that includes a beveled portion <NUM> along the width of the fuel cell door facing section <NUM>. However, the dosing lever body <NUM> of the dosing lever <NUM> of this illustrated known fastener driving tool <NUM> can interact with the fuel cell door <NUM> as the dosing lever body <NUM> pivots between the non-actuated position and the actuated position. This interaction between the dosing lever <NUM> and the fuel cell door <NUM> can inhibit movement during actuation of the dosing lever <NUM> such that the fuel supply assembly <NUM> does not dispense a full dose of fuel to the fastener driving assembly <NUM>. In certain circumstances, for each actuation cycle of the known dosing lever <NUM>, the interaction between the dosing lever <NUM> and the fuel cell door <NUM> causes the fuel supply assembly <NUM> to deliver a different amount of fuel to the fastener driving assembly <NUM>. As a result, the variation of fuel delivered to the fastener driving assembly <NUM> can cause variation in the combustion and operation of the known fastener driving tool <NUM>. The apparatus of the present disclosure overcomes these problems.

<FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> illustrate the combustion powered fastener driving tool of one example embodiment of the present disclosure that is generally indicated by numeral <NUM> (that is sometimes referred to herein as the "tool" for brevity). The illustrated example shows selected components of the tool <NUM> during actuation of the tool <NUM> to drive a fastener (not shown) into a workpiece. Other components of the tool <NUM> not discussed herein will be readily understood by those skilled in the art.

The illustrated example tool <NUM> includes, in part: (<NUM>) a housing <NUM>; (<NUM>) a fastener driving assembly <NUM> at least partially positioned in, supported by and connected to the housing <NUM>; (<NUM>) a fuel supply assembly <NUM> partially positioned in, supported by, and connected to the housing <NUM>; (<NUM>) a handle assembly <NUM> supported by and connected to the housing <NUM>; (<NUM>) a fastener magazine assembly <NUM> supported by and connected to the housing <NUM> and the handle assembly <NUM>; (<NUM>) a workpiece contact assembly <NUM> supported by and connected to the housing <NUM>; and (<NUM>) a nosepiece assembly <NUM> supported by and connected to a lower portion of the housing <NUM>. The illustrated example combustion powered fastener driving tool <NUM> in this example is known in the industry as is a mid-range combustion powered fastener driving tool; however, it should be understood that the present disclosure can also be applied to what is known in the industry as framing combustion powered fastener driving tools, what is known in the industry as trim combustion powered fastener driving tools, and other combustion powered tools.

The housing <NUM> includes, in part: (<NUM>) a first wall <NUM>; (<NUM>) a second wall <NUM> opposite of the first wall; and (<NUM>) a housing cap <NUM> suitably connected to the first and second walls <NUM> and <NUM> of the housing <NUM>. The housing <NUM> thus provides a suitable protective enclosure for the fastener driving assembly <NUM>, parts of the fuel supply assembly <NUM>, and other components of the tool <NUM>.

The fastener driving assembly <NUM> includes, in part: (<NUM>) a cylinder head <NUM> connected to the housing cap <NUM>; (<NUM>) a combustion chamber <NUM> suitably connected to the cylinder head <NUM>; (<NUM>) a fan motor <NUM> suitably mounted to the cylinder head <NUM> and projecting into the combustion chamber <NUM>; (<NUM>) a cylinder <NUM> suitably connected to the combustion chamber <NUM>; (<NUM>) a driving blade <NUM> suitably connected to the cylinder <NUM>; (<NUM>) a piston <NUM> positioned in the cylinder <NUM> and suitably connected to the driving blade <NUM>; and (<NUM>) a combustion chamber ring <NUM> positioned between the combustion chamber <NUM> and the cylinder head <NUM>. The combustion chamber ring <NUM> suitably connects the cylinder head <NUM> to an upper portion of the combustion chamber <NUM>.

The fuel supply assembly <NUM> includes, in part: (<NUM>) a fuel cell door <NUM> pivotally connected to the housing cap <NUM> of the housing <NUM>; (<NUM>) a fuel cell receiving assembly <NUM> positioned in and at least partially supported by the housing <NUM> and configured to receive a removable fuel cell <NUM>; (<NUM>) a fuel cell adapter <NUM> suitably connected to the fuel cell <NUM>; (<NUM>) a fuel cell metering valve <NUM> connected to the fuel cell adapter <NUM> and extending into a portion of the fuel cell <NUM>; (<NUM>) a fuel cell receiving block <NUM> connected to and in fluid communication with the fuel cell adapter <NUM>; (<NUM>) a fuel line <NUM> suitably connected between the fuel cell receiving block <NUM> and the cylinder head <NUM> to define a fuel pathway between the fuel cell <NUM> and the combustion chamber <NUM>; and (<NUM>) a dosing lever <NUM> pivotally supported in the housing <NUM> and engaged to the fuel cell receiving block <NUM>. The dosing lever <NUM> is further described below. It should be appreciated that while the fuel cell <NUM> and the fuel cell adapter <NUM> of the present disclosure are described herein as part of the fuel supply assembly <NUM> of the tool <NUM> for ease of description, that these components will typically be provided separately from the tool <NUM> and insertable in the tool <NUM>, and thus to a certain extent are not part of the fuel supply assembly <NUM>, but rather connectable to and operable with the fuel supply assembly <NUM> of the tool <NUM>.

The handle assembly <NUM> includes, in part: (<NUM>) a gripping portion <NUM>; (<NUM>) a trigger mount <NUM> defined on the gripping portion <NUM>; and (<NUM>) a trigger <NUM> suitably connected to the trigger mount <NUM> via a trigger pin (not shown) such that a portion of the trigger <NUM> can move relative to the gripping portion <NUM>. The handle assembly <NUM> is suitably connected to the housing <NUM>.

The fastener magazine assembly <NUM> includes, in part: (<NUM>) a fastener channel <NUM> configured to hold a plurality of fasteners (e.g., nails, or staples); and (<NUM>) a fastener channel <NUM> suitably connected to the nosepiece assembly <NUM> and to the handle assembly <NUM>. During operation of the tool <NUM>, a fastener is delivered, via the fastener channel <NUM>, to the nosepiece assembly <NUM> and driven into the workpiece by the fastener driving assembly <NUM>.

The workpiece contact assembly <NUM> includes, in part, a workpiece contact element <NUM> suitably connected to the nosepiece assembly <NUM> and to the fastener magazine assembly <NUM>. The workpiece contact element <NUM> contacts the location where the fastener is driven into the workpiece by the tool <NUM>. The nosepiece assembly <NUM> is suitably connected to the fastener magazine assembly <NUM> and to the cylinder <NUM>. The nosepiece assembly <NUM> receives a fastener from the fastener channel <NUM>. During operation of the tool <NUM>, the piston <NUM> is driven downward via the driving blade <NUM> in the cylinder <NUM>, contacts the fastener positioned in the nosepiece assembly <NUM> and drives the fastener into the workpiece.

The example dosing lever <NUM> of the present disclosure is now further described. <FIG> illustrate the example dosing lever <NUM> of the example fastener driving tool <NUM>. The dosing lever <NUM> includes: (<NUM>) a body <NUM>; (<NUM>) a first leg <NUM> connected to and extending from the body <NUM> along a first longitudinal axis (L1); (<NUM>) a second leg <NUM> connected to and extending from the body <NUM> along a second longitudinal axis (L2); (<NUM>) a first lever pivot pin <NUM> connected to and extending from the first leg <NUM>; and (<NUM>) a second lever pivot pin <NUM> connected to and extending from the second leg <NUM>.

The body <NUM> includes: (<NUM>) a leg connection section <NUM>; (<NUM>) a fuel cell door facing section <NUM>; and (<NUM>) a fuel block contact section <NUM>. The leg connection section <NUM> (that is sometimes referred to herein as the "front section") incudes: (<NUM>) a first leg connection portion <NUM> connected to the first leg <NUM>; and (<NUM>) a second leg connection portion <NUM> connected to the second leg <NUM>. The fuel cell door facing section <NUM> (that is sometimes referred to herein as the "rear section") includes: (<NUM>) a first beveled portion <NUM>; (<NUM>) a second beveled portion <NUM>; (<NUM>) a third beveled portion <NUM>; and (<NUM>) an upright portion <NUM> that connects the fuel cell door facing section <NUM> to the fuel block contact section <NUM>. The fuel block contact section <NUM> (that is sometimes referred to herein as the "bottom section") is configured to engage the fuel cell receiving block <NUM> upon actuation of the dosing lever <NUM>.

The first dosing lever leg <NUM> includes: (<NUM>) a connection portion <NUM> suitably connected to the first leg connection portion <NUM> of the body <NUM>; (<NUM>) a foot <NUM> opposite the connection portion <NUM>; and (<NUM>) a central portion <NUM> extending between and connected to the connection portion <NUM> and the foot <NUM>. In the illustrated example embodiment, the first lever pivot pin <NUM> is connected to and transversely extends outward from the connection portion <NUM> of the first dosing lever leg <NUM>.

The foot <NUM> of the first dosing lever leg <NUM> includes: (<NUM>) a toe <NUM>; (<NUM>) a heel <NUM>; and (<NUM>) a sole <NUM> extending between and connected to the toe <NUM> and the heel <NUM>. In the illustrated example embodiment, the sole <NUM> includes a substantially flat surface (within manufacturing tolerances) that defines a first contact surface <NUM> of the foot <NUM>. The toe <NUM> includes a sloped surface with respect to the sole <NUM> that defines a second contact surface <NUM> of the foot <NUM>. In this illustrated example embodiment, the second contact surface <NUM> can be completely flat or can have a slight curvature such as a having a radius of curvature of about <NUM> inch (<NUM> cms). In the illustrated example embodiment, the foot <NUM> forms or otherwise defines an angle (α1) of approximately <NUM> degrees between the first contact surface <NUM> of the sole <NUM> and the second contact surface <NUM> of the toe <NUM>. The foot <NUM> thus includes two flat or generally flat separate contact surfaces <NUM> and <NUM> that function for different purposes as described below.

The second leg <NUM> includes: (<NUM>) a connection portion <NUM> suitably connected to the second leg connection portion <NUM> of the body <NUM>; (<NUM>) a foot <NUM> opposite the connection portion <NUM>; and (<NUM>) a central portion <NUM> extending between the connection portion <NUM> and the foot <NUM>. In the illustrated example embodiment, the second lever pivot pin <NUM> is connected to and transversely extends outward from the connection portion <NUM> of the second dosing lever leg <NUM>.

The foot <NUM> of the second dosing lever leg <NUM> includes: (<NUM>) a toe <NUM>; (<NUM>) a heel <NUM>; and (<NUM>) a sole <NUM> extending between and connected to the toe <NUM> and the heel <NUM>. In the illustrated example embodiment, the sole <NUM> includes a substantially flat surface (within manufacturing tolerances) that defines a first contact surface <NUM> of the foot <NUM>. The toe <NUM> includes a sloped surface with respect to the sole <NUM> that defines a second contact surface <NUM> of the foot <NUM>. In this illustrated example embodiment, the second contact surface <NUM> can be completely flat or can have a slight curvature such as a having a radius of curvature of about <NUM> inch (<NUM> cms). In the illustrated example embodiment, the foot <NUM> forms an angle (α2) (not shown) that is the same or substantially the same as the angle (α1). Angle (α2) is approximately <NUM> degrees and formed between the first contact surface <NUM> of the sole <NUM> and the second contact surface <NUM> of the toe <NUM>. The foot <NUM> thus includes two flat or generally flat separate contact surfaces <NUM> and <NUM> that function for different purposes as described below.

In the illustrated example dosing lever <NUM>, the different beveled portions of the body <NUM> define sloped surfaces of the fuel cell door facing section <NUM>. More specifically, the first beveled portion <NUM> includes a substantially rectangular surface <NUM> defined by: (<NUM>) a first edge <NUM>; (<NUM>) a second edge <NUM> opposite the first edge <NUM>; (<NUM>) a third edge <NUM> connecting the first edge <NUM> and the second edge <NUM>; and (<NUM>) a fourth edge <NUM> opposite the third edge <NUM> and connecting the first edge <NUM> and the second edge <NUM>.

The second beveled portion <NUM> includes a substantially trapezoidal surface <NUM> defined by: (<NUM>) the third edge <NUM>; (<NUM>) a fifth edge <NUM> opposite the third edge <NUM>; (<NUM>) a sixth edge <NUM> connecting the third edge <NUM> and the fifth edge <NUM>; and (<NUM>) a seventh edge <NUM> opposite the sixth edge <NUM> and connecting the third edge <NUM> and the fifth edge <NUM>.

The third beveled portion <NUM> includes a substantially trapezoidal surface <NUM> defined by: (<NUM>) the fourth edge <NUM>; (<NUM>) an eighth edge <NUM> opposite the fourth edge <NUM>; (<NUM>) a ninth edge <NUM> connecting the fourth edge <NUM> and the eighth edge <NUM>; and (<NUM>) a tenth edge <NUM> opposite the ninth edge <NUM> and connecting the fourth edge <NUM> and the eighth edge <NUM>.

In the illustrated example embodiment, the rectangular surface <NUM> is a downwardly sloping surface that extends downward from the first edge <NUM> to the second edge <NUM> of the first beveled portion <NUM>. The trapezoidal surface <NUM> is defined at one end of the rectangular surface <NUM>. The trapezoidal surface <NUM> is a downwardly sloping surface that extends downward from the third edge <NUM> to the fifth edge <NUM> of the second beveled portion <NUM>. The trapezoidal surface <NUM> is defined at the other end of the rectangular surface <NUM>. The trapezoidal surface <NUM> is a downwardly sloping surface that extends downward from the fourth edge <NUM> towards the tenth edge <NUM>.

In the illustrated example embodiment, the downwardly sloping surfaces of the rectangular surface <NUM>, the trapezoidal surface <NUM>, and the trapezoidal surface <NUM> reduce a height or thickness of the fuel cell door facing section <NUM> of the body <NUM> (as compared to the known dosing lever described above). As discussed in more detail below, the beveled portions <NUM>, <NUM>, and <NUM> are configured such that the body <NUM> of the dosing lever <NUM> does not engage or otherwise contact the fuel cell door <NUM> during actuation of the dosing lever <NUM>.

As best shown in <FIG>, the dosing lever <NUM> engages the fuel cell receiving block <NUM> to dispense a dose of fuel from the fuel cell <NUM>. The fuel cell receiving block <NUM> is mounted on and connected to a valve stem <NUM> of the fuel cell adapter <NUM>. The fuel cell receiving block <NUM> includes an internal fuel passageway (not labeled) aligned with an internal fuel passageway (not labeled) of the valve stem <NUM> to fluidly couple the fuel cell <NUM> to the fuel cell receiving block <NUM>.

In the illustrated example embodiment, the dosing lever <NUM> is engaged to the fuel cell receiving block <NUM> and actuation of the dosing lever <NUM> transfers axial force from the dosing lever <NUM> to the fuel cell receiving block <NUM>. More specifically, actuation of the dosing lever <NUM> causes the fuel block contact section <NUM> to move downward and engage the fuel cell receiving block <NUM>. This downward movement of the fuel cell receiving block <NUM> causes a corresponding downward movement of the valve stem <NUM> of the fuel cell adapter <NUM> and the fuel cell metering valve <NUM>. As the fuel cell metering valve <NUM> moves downward, the valve draws a fuel dose from the fuel cell <NUM> into the fuel cell metering valve <NUM>. Non-actuation of the dosing lever <NUM> causes an upward movement of the fuel block contact section <NUM> and a corresponding upward movement of the fuel cell receiving block <NUM>. This upward movement of the fuel cell receiving block <NUM> causes a corresponding upward movement of the valve stem <NUM> and the fuel cell metering valve <NUM>. As the fuel cell metering valve <NUM> moves upward, the valve dispenses the fuel dose from the fuel cell <NUM> into the combustion chamber <NUM>.

Part of the operation of the example fastener driving tool <NUM> is also partially shown in <FIG>. In the illustrated example embodiment, the fastener driving tool <NUM> is configured to sequentially drive a plurality of fasteners (not shown) into a workpiece. Prior to actuation of the tool <NUM>, the dosing lever <NUM> is in a non-actuated position. As best shown in <FIG>, <FIG>, and <FIG>, the combustion chamber ring <NUM> includes a plurality of ring fingers <NUM> configured to selectively engage the feet <NUM> and <NUM> of the first and second legs <NUM> and <NUM>, respectively. As shown in <FIG>, when the dosing lever <NUM> is in the non-actuated position, the combustion chamber ring <NUM> is in the non-actuated position and the plurality of ring fingers <NUM> are in a non-engaged position with respect to the feet <NUM> and <NUM> of the dosing lever <NUM>.

In the illustrated example embodiment, when the dosing lever <NUM> is in the non-actuated position, the dosing lever <NUM> is pivoted about the first and second lever pivot pins <NUM> and <NUM> such that the first and second dosing lever legs <NUM> and <NUM> angle downward towards the combustion chamber ring <NUM> and the body <NUM> angles upward towards the fuel cell door <NUM>. More specifically, when the dosing lever <NUM> is in the non-actuated position, the first contact surfaces <NUM> and <NUM> of feet <NUM> and <NUM> are engaged to and supported by the cylinder head <NUM> and the beveled portions <NUM>, <NUM>, and <NUM> of the fuel cell door facing section <NUM> are adjacent the fuel cell door <NUM>. The beveled portions <NUM>, <NUM>, and <NUM> are configured such that the body <NUM> of the dosing lever <NUM> does not contact or otherwise engage the fuel cell door <NUM> when the dosing lever <NUM> is in the non-actuated position. In other words, the beveled portions <NUM>, <NUM>, and <NUM> define a gap between the fuel cell door facing section <NUM> of the body <NUM> and the inner surface of the fuel cell door <NUM> when the dosing lever <NUM> is in the non-actuated position.

When the operator is ready to actuate the tool <NUM>, the operator can cause the compression of the workpiece contact element <NUM> against a workpiece (not shown). This compression of the workpiece contact element <NUM> causes the combustion chamber ring <NUM> to move axially upwardly which causes the dosing lever <NUM> to pivot which causes the fuel cell receiving block <NUM> to push on the adapter <NUM> and causes the adapter <NUM> to push on the fuel cell metering valve <NUM> to cause a release of a dose of fuel from the fuel cell into the closed combustion chamber. At that point, subsequent compression of the trigger <NUM> that causes a spark in the closed combustion chamber can ignite the dose of fuel in the combustion chamber and drive the fastener (not shown) into the workpiece. Thus, as best shown in <FIG> and <FIG>, engaging the workpiece contact element <NUM> from the workpiece closes the combustion chamber and causes movement of the combustion chamber ring <NUM>, and the plurality of ring fingers <NUM>, in an axially upward direction towards the housing cap <NUM>. After driving the fastener into the workpiece, disengagement of the workpiece contact element <NUM> from the workpiece causes the combustion chamber to open and causes the downward axial movement of the combustion chamber ring <NUM> (including its plurality of fingers <NUM>) and thus disengagement of the dosing lever <NUM>. This disengagement of the dosing lever <NUM> causes the dosing lever <NUM> to pivot downwardly to be in a position ready for the next actuation of the workpiece contact element <NUM> and thus for the next combustion cycle of the tool <NUM>.

In the illustrated example embodiment, engagement between the combustion chamber ring fingers <NUM> and the dosing lever feet <NUM> and <NUM> causes the dosing lever <NUM> to pivot about the first and second lever pivot pins <NUM> and <NUM> from the non-actuated position into the actuated position. More specifically, when the dosing lever <NUM> pivots between the non-actuated position to the actuated position, the ring fingers <NUM> engage the respective second contact surfaces <NUM> and <NUM> of feet <NUM> and <NUM>. As such, the second contact surfaces <NUM> and <NUM> slide along the outer surface of the ring fingers <NUM> and the first contact surfaces <NUM> and <NUM> slide along the outer surface of the cylinder head <NUM>. As best shown in <FIG>, when the dosing lever <NUM> is in its fully actuated position, the second contact surfaces <NUM> and <NUM> are engaged with and supported by the ring fingers <NUM>.

In the illustrated example embodiment, as the combustion chamber ring moves the dosing lever <NUM> between the non-actuated and actuated position the first contact surfaces <NUM> and <NUM> and second contact surfaces <NUM> and <NUM> of the feet <NUM> and <NUM> are configured to slide smoothly along the ring fingers <NUM>. This engagement between the ring fingers <NUM> and the feet <NUM> and <NUM> causes a consistent and repeatable actuation of the dosing lever <NUM>, which in turn causes the fuel supply assembly <NUM> to deliver a consistent and repeatable dose of fuel from the fuel cell <NUM> to the combustion chamber <NUM> even in circumstances of extremely cold weather.

In the illustrated example embodiment, actuation of the dosing lever <NUM> also causes downward movement of the body <NUM> from the fuel cell door <NUM> towards the fuel cell <NUM>. This downward movement of the body <NUM> causes depression of the fuel cell receiving block <NUM>, the valve stem <NUM>, and the fuel cell metering valve <NUM>. As such, the fuel cell metering valve <NUM> draws a dose of fuel from the fuel cell <NUM> for delivery to the combustion chamber <NUM>. The first contact surfaces <NUM> and <NUM> and second contact surfaces <NUM> and <NUM> of the feet <NUM> and <NUM> are configured to slide smoothly along the ring fingers <NUM> as the combustion chamber ring moves the dosing lever <NUM> between the non-actuated and actuated position. This engagement between the ring fingers <NUM> and the feet <NUM> and <NUM> causes a consistent and repeatable actuation of the dosing lever <NUM>, which in turn causes the fuel supply assembly <NUM> to deliver a consistent and repeatable dose of fuel from the fuel cell <NUM> to the combustion chamber <NUM>.

In the illustrated example embodiment, as the dosing lever <NUM> moves between the non-actuated position (as shown in <FIG>) and the actuated position (as shown in <FIG>), the interaction between the dosing lever <NUM> and the fuel cell receiving block <NUM> causes the fuel metering valve to draw a dose of fuel from the fuel cell <NUM>. In the illustrated example embodiment, the beveled portions <NUM>, <NUM>, and <NUM> of the fuel cell door facing section <NUM> of the body <NUM> are configured to form a gap between the body <NUM> and the inner surface of the fuel cell door <NUM>. Accordingly, the beveled portions <NUM>, <NUM>, and <NUM> of the dosing lever <NUM> ensure that the dosing lever <NUM> can fully pivot between the non-actuated position and the actuated position without contacting the inner surface of the fuel cell door <NUM>. As such, each actuation cycle of the dosing lever <NUM> delivers a consistent and repeatable amount of fuel from the fuel cell <NUM> to the combustion chamber <NUM> even in circumstances of extremely cold weather.

Claim 1:
A fastener driving tool (<NUM>) comprising:
a housing (<NUM>);
a fastener driving assembly (<NUM>) at least partially positioned in the housing, the fastener driving assembly including:
a cylinder head (<NUM>) connected to the housing,
a combustion chamber (<NUM>) connected to the cylinder head,
a cylinder (<NUM>) connected to the combustion chamber, and
a combustion chamber ring (<NUM>) between the combustion chamber and the cylinder head, the combustion chamber ring movable from an actuated position to a non-actuated position;
a workpiece contact assembly (<NUM>) connected to the housing; and
a fuel supply assembly (<NUM>) at least partially in the housing, the fuel supply assembly including:
a fuel cell receiving assembly (<NUM>) in the housing, the fuel cell receiving assembly configured to receive a fuel cell (<NUM>);
a fuel cell receiving block (<NUM>), and
a dosing lever (<NUM>) pivotally supported by the housing and pivotable from a non-actuated position to an actuated position to cause a dose of fuel to be dispensed from the fuel cell, the dosing lever including a first contact surface (<NUM>) engagable with the cylinder head when the dosing lever is in the non-actuated position,
characterized in that the fuel cell receiving assembly (<NUM>) is configured to receive a fuel cell adapter (<NUM>) connectible to the fuel cell (<NUM>), the fuel cell receiving block (<NUM>) is shaped and sized to receive the fuel cell adapter, and the dosing lever (<NUM>) includes a second contact surface (<NUM>) that is slidably engageable by a ring finger (<NUM>) of the combustion chamber ring (<NUM>) when the dosing lever is moved from the non-actuated position to the actuated position.