Patent Publication Number: US-2023158651-A1

Title: Fuel cell adapter for fastener driving tool

Description:
PRIORITY 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/282,392, filed Nov. 23, 2021, the contents of which are incorporated herein by reference in their entirety. 
    
    
     FIELD 
     The present disclosure relates to fastener driving tools, specifically to combustion powered fastener driving tools with improved fuel cell adapters. 
     BACKGROUND 
     Generally, 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&#39;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 typically 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: (1) a valve sleeve of the tool to move to a sealed position to seal a combustion chamber of the tool that is in fluid communication with the cylinder; and (2) a fuel delivery system of the tool to dispense fuel from a replaceable fuel cell positioned in the tool 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 delivery system is configured to receive a replaceable fuel cell and dispense a desired amount of fuel to the combustion chamber for each combustion event. The replaceable fuel cell should be sealed within the combustion powered fastener driving tool to prevent unwanted leakage of fuel from the fuel cell. 
     However, to seal the fuel supply stored in the fuel delivery system, certain known combustion powered fastener driving tools rely on sealing components that are susceptible to performance degradation caused by changes in environmental conditions (such as extreme heat or cold), dimensional tolerances, age, and other conditions. For example, when certain known combustion powered fastener driving tools operate in relatively cold temperatures, they do not optimally perform. For example, the sealing components of the fuel delivery systems of these known tools may provide variable sealing of the fuel cell such that under certain conditions current combustion powered fastener driving tools experience fuel leaks from these sealing components that engage the replaceable fuel cell in the tool. Thus, there is a need for a combustion powered fastener driving tool that provides more consistent and stable sealing components of the fuel delivery system that minimize fuel leakage. 
     SUMMARY 
     Various embodiments of the present disclosure provide a combustion powered fastener driving tool that solves the above problems in part by including more stable fluid tight seal for a fuel assembly to better minimize fuel leakage. 
     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 assembly at least partially positioned in, supported by, and connected to the housing. The fuel assembly includes or is configured to receive a fuel cell adapter that is shaped and sized to better engaged and be better engaged by a fuel cell receiving block to better sealingly engage the fuel cell adapter connected to a replaceable fuel cell that stores a fuel supply for the fastener driving tool. 
     Other objects, features, and advantages of the present disclosure will be apparent from the following detailed disclosure and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    is an enlarged fragmentary side cross-sectional view of part of a known fastener driving tool showing the fuel assembly mounted in the housing and showing part of the fastener driving assembly. 
         FIG.  2    is an enlarged fragmentary cross-sectional view of a part of the known fuel assembly of the fastener driving tool of  FIG.  1   , showing the fuel cell block mounted on a known fuel cell adapter. 
         FIG.  3    is a side perspective view of a fastener driving tool of the one example embodiment of the present disclosure. 
         FIG.  4    is an enlarged perspective view of the fuel cell adapter of the fastener driving tool of  FIG.  3   , showing an arcuate outer surface of at least a portion of the adapter stem of the fuel cell adapter. 
         FIG.  5    is an enlarged side view of the fuel cell adapter of  FIG.  4   , showing the arcuate outer surface of a portion of the adapter stem of the fuel cell adapter. 
         FIG.  6    is an enlarged top view of the fuel cell adapter of  FIG.  4   . 
         FIG.  7    is an enlarged side cross-sectional view of the fuel cell adapter of  FIG.  4   , showing the arcuate outer surface of a portion of the adapter stem of the fuel cell adapter. 
         FIG.  8    is an enlarged cross-sectional view of a portion of the fuel assembly of the fastener driving tool of  FIG.  3   , showing the fuel cell block mounted on the adapter stem of the fuel cell adapter of  FIG.  4   . 
         FIG.  9    is an enlarged fragmentary side cross-sectional view of a portion of the fuel assembly of the fastener driving tool of  FIG.  3   , showing the fuel cell block mounted on the adapter stem of the fuel cell adapter of  FIG.  4   . 
         FIG.  10    is an enlarged fragmentary cross-sectional view of the fastener driving tool of  FIG.  3   , showing the fuel assembly mounted in the housing and showing the fastener driving assembly including the fuel cell adapter of  FIG.  4   . 
     
    
    
     DETAILED DESCRIPTION 
     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. Various embodiments of the combustion powered fastener driving tool of the present disclosure can include certain identical or similar components as described below. 
       FIGS.  1  and  2    illustrate an example known combustion powered fastener driving tool  50  (that is sometimes referred to herein as “known tool” for brevity).  FIGS.  1  and  2    show selected components of the example known tool  50  including: (1) a housing  100 ; (2) a fastener driving assembly  200  partially positioned in, supported by, and connected to the housing  100 ; and (3) a fuel assembly  300  partially positioned in, supported by, and connected to the housing  100 . 
     In the illustrated fastener driving tool  50 , the fastener driving assembly  200  includes: (1) a cylinder head  210 ; (2) a combustion chamber  220  suitably connected to the cylinder head  210 ; (3) a fan motor  230  suitably mounted to the cylinder head  210  and projecting into the combustion chamber  220 ; (4) a sleeve  240  suitably connected to the combustion chamber  220 ; and (5) a combustion chamber ring  250  suitably connected to an upper portion of the combustion chamber  220  and the cylinder head  210 . 
     In the illustrated fastener driving tool  50 , the fuel assembly  300  includes: (1) a fuel cell door  310  pivotally connected to the housing  100 ; (2) a fuel cell  320  receivable in and at least partially supported by the housing  100 ; (3) a fuel cell adapter  400  suitably connected to the fuel cell  320 ; (5) a fuel cell metering valve  340  that fluidly communicates with the fuel cell adapter  400  and extending into a portion of the fuel cell  320 ; (6) a fuel cell receiving block  350  mounted on, connected to, and in fluid communication with the fuel cell adapter  400 ; (7) a fuel line  360  suitably connected between the fuel cell receiving block  350  and the cylinder head  210  to define a fuel pathway between the fuel cell  320  and the combustion chamber  220 ; and (8) a fuel dosing lever  370  pivotally supported by the cylinder head  210  and engaged to the fuel cell receiving block  350 . 
     In the illustrated fastener driving tool  50 , the fuel cell adapter  400  includes: (1) a fuel cell connector  410 ; and (2) a stem  420  suitably connected to the fuel cell connector  410 . The fuel cell adapter  400  is partially positioned in and received by the fuel cell receiving block  350  to fluidly connect the fuel cell  320  to the fuel cell receiving block  350  as best shown in  FIG.  2   . In the illustrated known fastener driving tool  50 , the fuel cell receiving block  350  includes a plurality of inner surfaces  352  that define an inner stem receiving bore  354 . The top surface  422  of the stem  420  of the fuel cell adapter  400  is configured to mate with and create a seal with the bottom surface  356  of the top portion of the stem receiving bore  354  of the fuel cell receiving block  350 . During operation, the stem  420  extends into the stem receiving bore  354  such that the fuel cell adapter  400  is in fluid communication with the fuel cell receiving block  350 . 
     More specifically, in this known tool  50 , the horizontally extending top surface  439  of the cylindrical portion  438  of the stem  420  engages the horizontally extending bottom inner sealing surface  356  of the stem receiving bore  354 . Engagement between these inner surface is meant to form a fluid tight seal between the stem  420  and the fuel cell receiving block  350 . However, when the fuel cell  320  is installed in the tool  50  and the fuel cell adapter  400  is engaged to the fuel cell receiving block  350 , in certain circumstances (that can be worse in relatively cold temperatures), certain movements and/or repositioning of the fuel cell receiving block  350  relative to the fuel cell adapter  400  (such as caused by actuation of the dosing lever of the tool  50 ) can cause the disengagement of these surfaces  439  and  356 . Accordingly, certain movements of the fuel cell receiving block  350  with respect to the stem  420  can break the seal formed between the fuel cell adapter  400  and the fuel cell receiving block  350 . As a result, fuel can leak from the fuel cell  320  into other portions of the known tool  50  in an undesired manner in such certain circumstances. 
       FIGS.  3  to  10    illustrate the combustion powered fastener driving tool of one example embodiment of the present disclosure that is generally indicated by numeral  1050  (and sometimes referred to herein as the “tool” for brevity). The illustrated example shows selected components of the tool  1050  during actuation of the tool  1050  to drive a fastener (not shown) into a workpiece. Other components of the tool  1050  not discussed herein will be readily understood by those skilled in the art. 
     The illustrated example tool  1050  includes: (1) a housing  1100 ; (2) a fastener driving assembly  1200  at least partially positioned in, supported by and connected to the housing  1100 ; (3) a fuel assembly  1300  partially positioned in, supported by, and connected to the housing  1100 ; (4) a handle assembly  1500  supported by and connected to the housing  1100 ; (5) a fastener magazine assembly  1600  supported by and connected to the housing  1100  and the handle assembly  1500 ; (6) a workpiece contact assembly  1700  supported by and connected to the housing  1100 ; and (7) a nosepiece assembly  1800  supported by and connected to a lower portion of the housing  1100 . The illustrated example combustion powered fastener driving tool  1050  in this example is known in the industry as 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  1100  includes: (1) a first wall  1110 ; (2) a second wall  1120  opposite of the first wall; and (3) a housing cap  1130  suitably connected to the first and second walls  1110  and  1120  of the housing  1100 . The housing  1100  thus provides a suitable protective enclosure for the fastener driving assembly  1200 , parts of the fuel assembly  1300 , and other components of the tool  1050 . 
     The fastener driving assembly  1200  includes: (1) a cylinder head  1210  connected to the housing cap  1130 ; (2) a combustion chamber  1220  suitably connected to the cylinder head  1210 ; (3) a fan motor  1230  suitably mounted to the cylinder head  1210  and projecting into the combustion chamber  1220 ; (4) a cylinder  1240  suitably connected to the combustion chamber  1220 ; (5) a driving blade  1250  suitably connected to the cylinder  1240 ; (6) a piston  1260  positioned in the cylinder  1240  and suitably connected to the driving blade  1250 ; and (7) a combustion chamber ring  1270  positioned between the combustion chamber  1220  and the cylinder head  1210 . The combustion chamber ring  1270  suitably connects the cylinder head  1210  to an upper portion of the combustion chamber  1220 . 
     The fuel assembly  1300  includes: (1) a fuel cell door  1310  pivotally connected to the housing cap  1130  of the housing  1100 ; (2) a fuel cell receiving assembly  1320  positioned in and at least partially supported by the housing  1100  and configured to receive a removable fuel cell  1330 ; (3) a fuel cell adapter  1400  suitably connected to the fuel cell  1330 ; (4) a fuel cell metering valve  1340  connected to the fuel cell adapter  1400  and extending into a portion of the fuel cell  1330 ; (5) a fuel cell receiving block  1350  connected to and in fluid communication with the fuel cell adapter  1400 ; (6) a fuel line  1360  suitably connected between the fuel cell receiving block  1350  and the cylinder head  1210  to define a fuel pathway between the fuel cell  1330  and the combustion chamber  1220 ; and (7) a fuel dosing lever  1370  pivotally supported in the housing  1100  and engageable with the fuel cell receiving block  1350 . The fuel cell receiving block  1350  and the fuel cell adapter  1400  are further described below. It should be appreciated that while the fuel cell  1330  and the fuel cell adapter  1400  of the present disclosure are described herein as part of the fuel assembly  1300  of the tool  1050  for ease of description, that these components will typically be provided separately from the tool  1050  and insertable in the tool  1050 , and thus to a certain extent are not part of the fuel assembly  1300 , but rather connectable to and operable with the fuel assembly  1300  of the tool  1050 . 
     The handle assembly  1500  includes: (1) a gripping portion  1510 ; (2) a trigger mount  1520  defined on the gripping portion  1510 ; and (3) a trigger  1530  suitably connected to the trigger mount  1520  via a trigger pin (not shown) such that a portion of the trigger  1530  can move relative to the gripping portion  1510 . The handle assembly  1500  is suitably connected to the housing  1100 . 
     The fastener magazine assembly  1600  includes: (1) a fastener cannister  1610  configured to hold a plurality of fasteners (e.g., nails, or staples); and (2) a fastener channel  1620  suitably connected to the nosepiece assembly  1800  and to the fastener cannister  1610 . During operation of the tool  1050 , a fastener is delivered, via the fastener channel  1620 , to the nosepiece assembly  1800  and driven into the workpiece by the fastener driving assembly  1200 . 
     The workpiece contact assembly  1700  includes a workpiece contact element  1710  suitably connected to the nosepiece assembly  1800  and to the fastener magazine assembly  1600 . The workpiece contact element  1710  contacts the location where the fastener is driven into the workpiece by the tool  1050 . 
     The nosepiece assembly  1800  is suitably connected to the fastener magazine assembly  1600  and to the cylinder  1240 . The nosepiece assembly  1800  receives a fastener from the fastener channel  1620 . During operation of the tool  1050 , the piston  1260  is driven downward, via the driving blade  1250 , in the cylinder  1240 , contacts the fastener positioned in the nosepiece assembly  1800  and drives the fastener into the workpiece. 
     The fuel cell receiving block  1350  and the example fuel cell adapter  1400  of the present disclosure are now further described.  FIGS.  4  to  10    illustrate the example fuel cell adapter  1400 . The illustrated example fuel cell adapter  1400  includes: (1) a fuel cell connector  1410 ; and (2) a stem  1430  suitably connected to the fuel cell connector  1410  via a first arm  1460  and via a second arm  1470 . In the illustrated example, the fuel cell adapter  1400  is fabricated from a suitable polymer or plastic material configured to withstand the operational conditions of the tool  1050 . As such, the fuel cell adapter  1400  can be molded or otherwise fabricated to form a monolithic structure including the fuel cell connector  1410 , the stem  1430 , the first arm  1460 , the second arm  1470  and other such moldable features and components of the fuel cell adapter  1400 . It should be understood that the stem  1430 , the first arm  1460 , and the second arm  1470  can alternatively be formed as two or more separate components that are suitably connected or that are fastened to the fuel cell connector  1410  during fabrication of the fuel cell adapter  1400 . 
     The fuel cell connector  1410  includes: (1) a fuel cell connection portion  1412 ; (2) a first flange  1414 ; (3) a second flange  1416 ; and (4) a plurality of interior surfaces  1418  that define a fuel cell receiver  1420  shaped and sized to receive at least a portion of the fuel cell metering valve  1340  and the fuel cell  1330 . In the illustrated example embodiment, the fuel cell adapter  1400  engages a top  1322  of the fuel cell  1330  and the fuel cell connector  1410  and the second flange  1416  engage a bead  1324  that circumferentially surrounds the top  1322  of the fuel cell  1330 . Engagement of the fuel cell adapter  1400  with the fuel cell  1330  causes at least a portion of the fuel cell  1330  to extend into the fuel cell receiver  1420 . In the illustrated example embodiment, at least a portion of the fuel cell metering valve  1340  extends through the fuel cell receiver  1420  and into the stem  1430  to fluidly connect the fuel cell  1330  to the fuel cell adapter  1400 . 
     In certain embodiments, the fuel cell adapter  1400  is fixedly attached to the to the fuel cell  1330  such that the fuel cell adapter  1400  and the fuel cell  1330  form a unitary component that can be connected and removed from the tool  1050 . In other embodiments, the fuel cell  1330  is removable from the fuel cell adapter  1400  such that the fuel cell  1330  can be disconnected from the fuel cell adapter  1400  and replaced with a different fuel cell. The fuel cell connector of the fuel cell adaptor can be configured as various different manners in accordance with the present disclosure such as but not limited to the configurations described in commonly assigned U.S. Pat. Nos. 10,166,666, 10,654,156, and 10,850,378, all of which are incorporated by reference herein. 
     In the illustrated example fuel cell adapter  1400 , the stem  1430  includes: (1) a base  1432  suitably connected to the first arm  1460  and the second arm  1470 ; (2) a first conical portion  1434  connected to, supported by and extending axially upward from the base  1432 ; (3) a sealing portion  1436  connected to, supported by and extending axially upward from the first conical portion  1434 ; and (4) a second conical portion  1438  connected to, supported by and extending axially upward from the sealing portion  1436 . 
     The first arm  1460  includes: (1) a stem attachment portion  1462  suitably connected to the base  1432  of the stem  1430 ; (2) a connector attachment portion  1464  suitably connected to the fuel cell connector  1410 ; and (3) a central portion  1466  extending between the stem attachment portion  1462  and the connector attachment portion  1464 . 
     The second arm  1470  includes: (1) a stem attachment portion  1472  suitably connected to the base  1432  of the stem  1430 ; (2) a connector attachment portion  1474  suitably connected to the fuel cell connector  1410 ; and (3) a central portion  1476  extending between the stem attachment portion  1472  and the connector attachment portion  1474 . 
     The first arm  1460  and the second arm  1470  form a spiral support structure that connects the stem  1430  to the fuel cell connector  1410 . As best shown in  FIGS.  4 ,  6 ,  7 ,  8 , and  10   , the first arm  1460  and the second arm  1470  position the stem  1430  in at least a portion of the fuel cell receiver  1420  of the fuel cell adapter  1400  such that the stem  1430  connects to the fuel cell metering valve  1340 . 
     In the illustrated example fuel cell adapter  1400 , the different sections of the stem  1430  have specific shapes and dimensions that cause specific desired engagements and seals or sealing locations between the fuel cell adapter  1400  and the fuel cell receiving block  1350 . 
     In this example, the stem  1430  includes: (1) a first outer diameter (D 1 ) that is substantially between 0.30 and 0.35 inches (0.762 to 0.889 cms) (e.g., within manufacturing tolerances) to define a width of the base  1432 ; (2) a second outer diameter (D 2 ) that is substantially between 0.27 and 0.29 inches (0.6858 to 0.7366 cms) (e.g., within manufacturing tolerances) to define a width of a bottom end  1440  of the first conical portion  1434 ; (3) a third outer diameter (D 3 ) that is substantially between 0.250 and 0.265 inches (0.635 to 0.6731 cms) (e.g., within manufacturing tolerances) to define a width of a top end  1441  of the first conical portion  1434 , the third outer diameter (D 3 ) also defines the width of a bottom end  1442  of the sealing portion  1436 ; (4) a fourth outer diameter (D 4 ) that is substantially between 0.14 and 0.16 inches (0.3556 to 0.4964 cms) (e.g., within manufacturing tolerances) to define a width of a top end  1443  of the sealing portion  1436 , the fourth outer diameter (D 4 ) also defines the width of a bottom end  1444  of the second conical portion  1438 ; and (5) a fifth outer diameter (D 5 ) that is substantially between 0.14 and 0.16 inches (0.3556 to 0.4964 cms) (e.g., within manufacturing tolerances) to define a width of a top end  1445  of the second conical portion  1438 . 
     In the illustrated example embodiment, D 1 &gt;D 2 &gt;D 3 &gt;D 4  and D 4  and D 5  are about equal (or such that D 5  is slightly less than D 4 ) such that the base  1432  has the largest outer diameter (i.e., D 1 ) and the second conical portion  1438  has the smallest outer diameter (i.e., D 5 ). D 2  is larger than D 3  such that the first conical portion  1434  is tapered between the bottom end  1440  and the top end  1441  of the first conical portion  1434 . D 3  is larger than D 4  such that the sealing portion  1436  includes an arcuate or domed shaped outer sealing surface  1453  defined along the outer surface and extending between the bottom end  1442  and the top end  1443  of the sealing portion  1436 . D 4  is larger than D 5  such that the second conical portion  1438  is tapered between the bottom end  1444  and the top end  1445  of the second conical portion  1438 . As further described below, the outer sealing surface  1453  of the sealing portion  1436  (rather than the top end  1445 ) is shaped and sized to engage the fuel cell receiving block  1350  and form a fluid tight seal between the fuel cell adapter  1400  and fuel cell receiving block  1350 ). In the illustrated example, the outer sealing surface  1453  is defined axially below the second conical portion  1438 . 
     In the illustrated example embodiment, the stem  1430  has a height (H 1 ) extending between the base  1432  and the second conical portion  1438  that is substantially between 0.53 and 0.54 inches (1.3462 to 1.3716 cm) (e.g., within manufacturing tolerances). The second conical portion  1438  has a height (H 2 ) extending between the bottom end  1444  and the top end  1445  of the second conical portion that is substantially between 0.050 and 0.055 inches (0.127 to 0.1397 cm) (e.g., within manufacturing tolerances). As further described below, the height (H 2 ) of the second conical portion  1438  of the stem  1430  is shaped and sized to define a fuel receiving gap  1387  or space between the second conical portion  1438  of the stem  1430  and the fuel cell receiving block  1350 . The fuel receiving gap  1387  has a height (H 3 ) defined between the second conical portion  1438  and the fuel cell receiving block  1350 . In the illustrated example embodiment, the second conical portion  1438  of the stem  1430  does not engage or contact the fuel cell receiving block  1350 . 
     In the illustrated example fuel cell adapter  1400 , the different sections or portions of the stem  1430  have a plurality of interior surfaces that define a metering valve receiver  1446  and a fuel passageway  1447  in the stem  1430 . For example, the metering valve receiver  1446  includes: (1) a first cylindrical inner surface  1448 ; (2) a first annular inner surface  1449  connected to the first cylindrical inner surface  1448 ; (3) a second cylindrical inner surface  1450  connected to the first annular inner surface  1449 ; and (4) a second annular surface  1451  connected to the first cylindrical surface  1448 . The fuel passageway  1447  includes a conical surface  1452  connected to the second annular surface  1451  of the metering valve receiver  1446  and extends through the top end  1445  of the second conical portion  1438  of the stem  1430 . In the illustrated example, the metering valve receiver  1446  is shaped and sized to receive at least a portion of the fuel cell metering valve  1340 . The fuel passageway  1447  is fluidly connected to the metering valve receiver  1446  such that fuel dispensed from the fuel cell metering valve  1340  is transported through the fuel passageway  1447  and into the fuel cell receiving block  1350 . 
       FIGS.  8  to  10    illustrate the example fuel cell receiving block  1350  of the tool  1050 . The fuel cell receiving block  1350  is fluidly connected to the fuel cell adapter  1400  and shaped and sized to sealingly engage and connect to the stem  1430 . The illustrated example fuel cell receiving block  1350  includes: (1) a stem connector  1352 ; (2) a dosing lever engager  1354 ; and (3) a fuel line connector  1356 . 
     In the illustrated example embodiment, the stem connector  1352  of the fuel cell receiving block  1350  includes a stem receiving portion  1380  defined by a plurality of surfaces of the fuel cell receiving block  1350 . More specifically, the stem receiving portion  1380  is defined by: (1) an outer annular surface  1381 ; (2) an inner conical surface  1382  connected to the outer annular surface  1381  via a fillet  1383 ; (3) an inner sealing surface  1384  connected to the inner conical surface  1382 ; (4) an inner cylindrical surface  1385  connected to the inner conical surface  1382 ; and (5) an inner bottom annular surface  1386  connected to the inner cylindrical surface  1385 . 
     In the illustrated example embodiment, the shape and size of the stem receiving portion  1380  is configured to correspond to the shape and size of the stem  1430  of the fuel cell adapter  1400 . As best shown in  FIGS.  8  and  9   , the stem  1430  of the fuel cell adapter  1400  is received by the stem receiving portion  1380  and engaged to least a portion of the fuel cell receiving block  1350 . More specifically, the inner conical surface  1382  of the stem receiving portion  1380  corresponds with the tapered shape of the first conical portion  1434  of the stem  1430 . The width of the stem receiving portion  1380  defined by the inner conical surface  1382  is slightly larger than the width of the first conical portion  1434 . As such, when the fuel cell receiving block  1350  is connected to the fuel cell adapter  1400 , there is a fuel receiving gap between the inner conical surface  1382  of the stem receiving portion  1380  and the first conical portion  1434  of the stem  1430 . 
     In the illustrated example embodiment, the inner sealing surface  1384  of the stem receiving portion  1380  has an arcuate or domed shape that corresponds with the arcuate or domed shape of the sealing portion  1436  of the stem  1430 . At least a portion of a width of the stem receiving portion  1380  defined by the inner sealing surface  1384  is substantially equal to (e.g., within manufacturing tolerances) at least a portion of the width of the sealing portion  1436 . As such, when the fuel cell receiving block  1350  is connected to the fuel cell adapter  1400 , a fluid tight seal is formed between at least a portion of the inner sealing surface  1384  of the fuel cell receiving block  1350  and the outer sealing surface  1453  of the sealing portion  1436  of the stem  1430 . 
     In the illustrated example embodiment, the outer sealing surface  1453  is defined axially below the second conical portion  1438  of the stem  1430 . As such, the arcuate, concave, or domed shape of the inner sealing surface  1384  of the fuel cell receiving block  1350  and the corresponding arcuate, convex, or domed shaped of the outer sealing surface  1453  of the stem  1430  enables adjustment of the fluid tight seal formed between the fuel cell receiving block  1350  and the fuel cell adapter  1400 . Thus, the fluid tight seal formed between the inner sealing surface  1384  of the fuel cell receiving block  1350  and the outer sealing surface  1453  of the fuel cell adapter  1400  is maintained if the fuel cell receiving block  1350  moves with respect to the stem  1430 . In other words, even if the fuel cell receiving block  1350  moves, the arcuate or domed shape of the outer sealing surface  1453  and the inner sealing surface  1384  enables the stem  1430  to remain sealingly engaged to the fuel cell receiving block  1350 . In a wide range of conditions (including in relatively cold temperatures), various different movements and/or repositioning of the fuel cell receiving block  1350  relative to the fuel cell adapter  1400  (such as certain pivotal movements) will not cause fuel leakage or will have extremely reduced amounts of fuel leakage. 
     In the illustrated example embodiment, the inner cylindrical surface  1385  and the inner bottom annular surface  1386  of the stem receiving portion  1380  correspond with tapered shape of the second conical portion  1438  of the stem  1430 . The width of the stem receiving portion  1380  defined by the inner cylindrical surface  1385  is slightly larger than the width of the second conical portion  1438  of the stem  1430 . The height of the stem receiving portion  1380  defined by the inner cylindrical surface  1385  and the inner bottom annular surface  1386  is slightly larger than the height (H 2 ) of the second conical portion  1438  of the stem  1430 . As such, when the fuel cell receiving block  1350  is connected to the fuel cell adapter  1400  there is a slight fuel receiving gap  1387  between inner cylindrical surface  1385  and the inner bottom annular surface  1386  of the stem receiving portion  1380  and the second conical portion  1438  of the stem  1430 . In other words, when the fuel cell receiving block  1350  is connected to the fuel cell adapter  1400  the second conical portion  1438  of the stem  1430  is not engaged with the inner cylindrical surface  1385  and the inner bottom annular surface  1386  of the fuel cell receiving block  1350 . 
     In the illustrated example embodiment, a plurality of surfaces define a fuel passageway  1390  in the fuel cell receiving block  1350 . More specifically, inner surfaces  1391  define the fuel passageway  1390  extending through the dosing lever engager  1354  and the fuel line connector  1356  of the fuel cell receiving block  1350 . The fuel passageway  1390  includes a first end  1392  connected to the inner bottom annular surface  1386  and in communication with the stem receiving portion  1380 . The fuel passageway  1390  includes a second end  1393  that exits through the fuel line connector  1356  of the fuel cell receiving block  1350 . 
     As shown in  FIGS.  8  to  10   , the fuel cell receiving block  1350  is mounted on the stem  1430  of the fuel cell adapter  1400  via the stem connector  1352 . The stem  1430  extends into the stem receiving portion  1380  and sealingly engages with at least a portion of the fuel cell receiving block  1350 . In the illustrated example embodiment, the stem  1430  of the fuel cell adapter  1400  extends into the stem receiving portion  1380  such that the at least a portion of the outer sealing surface  1453  of the sealing portion  1436  engages at least a portion of the inner sealing surface  1384  of the stem receiving portion  1380  to form a fluid tight seal between the fuel cell adapter  1400  and fuel cell receiving block  1350 . The fuel passageway  1390  of the fuel cell receiving block  1350  is aligned with the fuel passageway  1447  of the stem  1430  to fluidly couple the fuel cell  1330  to the fuel cell receiving block  1350  and the fuel line  1360 . 
     As best shown in  FIG.  10   , actuation of the fuel dosing lever  1370  transfers an axial force from the fuel dosing lever  1370  to the fuel cell receiving block  1350 . More specifically, actuation of the fuel dosing lever  1370  causes a subsequent actuation of the fuel cell receiving block  1350  and the stem  1430  of the fuel cell adapter  1400 . In the illustrated example embodiment, actuation of the stem  1430  causes the fuel cell metering valve  1340  to draw a desired fuel dose from the fuel cell  1330 . The fuel dose is then transported through the fuel passageway  1447  of the fuel cell adapter  1400 , through the fuel passageway  1390  of the fuel cell receiving block  1350  and the fuel line  1360  and into the combustion chamber  1220  of the tool  1050 . 
     During operation of the tool  1050 , the fluid tight seal formed between the outer sealing surface  1453  of the stem  1430  and the inner sealing surface  1384  of the fuel cell receiving block  1350  prohibits fuel from leaking out of the fuel cell  1330 . During non-operation and/or idle conditions of the tool, the fuel assembly  1300  maintains the fluid tight seal between the sealing portion  1436  of the stem  1430  and the inner sealing surface  1384  of the fuel cell receiving block  1350 . As a result, engagement between the sealing portion  1436  of the stem  1430  and the inner sealing surface  1384  of the fuel cell receiving block prohibits or substantially reduces fuel from leaking out of the fuel cell due to a change of environmental conditions, (e.g., increase or decrease in temperature), a change of fuel cell pressure, or any other such condition. 
     In the illustrated example embodiment, when the fuel cell receiving block  1350  is connected to the fuel cell adapter  1400 , the height (H 2 ) of the second conical portion  1438  causes a fuel receiving gap  1387  between the inner cylindrical surface  1385  and the inner bottom annular surface  1386  of the stem receiving portion  1380  and the second conical portion  1438  of the stem  1430 . As such, fuel from the fuel cell  1330  can fill the fuel receiving gap  1387  between the second conical portion  1438  of the stem  1430  and the inner cylindrical surface  1385  and inner bottom annular surface  1386  of the fuel cell receiving block  1350 . However, since the fluid tight seal formed between the outer sealing surface  1453  of the stem  1430  and the inner sealing surface  1384  of the fuel cell receiving block  1350  is axially below this fuel receiving gap, any fuel that fills the fuel receiving gap  1387  does not leak. Thus, the fuel cell receiving block  1350  and the fuel cell adapter  1400  form a fuel receiving gap therebetween and that is above the respective sealing surfaces of the fuel cell receiving block  1350  and the fuel cell adapter  1400 . 
     Other embodiments of the fuel cell adapter are contemplated by the present disclosure. In various such embodiments, the second conical portion  1438  has a different shape and/or size than is shown and described in the above embodiment. In various other such embodiments, the second conical portion  1438  is reduced in size or eliminated. 
     Further embodiments of the fuel cell adapter are contemplated by the present disclosure. In various such embodiments, the stem is configured to be connected to a value of the fuel cell and the fuel cell adapter does not include the fuel cell connector or the arms connecting the stem to the connector. 
     Various changes and modifications to the present embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.