Abstract:
The present invention provides a head valve assembly for a pneumatic fastener including a piston assembly reciprocated within a cylinder assembly for driving a fastener and a housing having an end cap for at least partially enclosing the head valve assembly. The head valve assembly includes a valve piston for causing supply pressure to be ported to the piston assembly for moving the piston assembly within the cylinder assembly from a non-actuated position to an actuated position for driving the fastener. Further, an inner cap is disposed within the end cap around the valve piston. The inner cap includes an inlet port for porting pressure to the valve piston. In addition, a main seal is coupled to the valve piston for sealing the cylinder assembly from supply pressure while pressure is ported to the valve piston by the inner cap for holding the piston assembly in the non-actuated position. The main seal seals pressure ported to the valve piston by the inner cap from supply pressure ported to the piston assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 60/546,685, entitled “Oil Free Head Valve for Pneumatic Nailers and Staplers,” filed Feb. 20, 2004 which is herein incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to the field of power tools, and particularly to a head valve assembly for pneumatic fasteners, such as pneumatic nailers and staplers.  
       BACKGROUND OF THE INVENTION  
       [0003]     Pneumatic power tools are commonly employed in a variety of work places in order to accomplish various tasks. Typical pneumatic power tools include pneumatic fasteners, such as pneumatic nailers and pneumatic staplers. A typical system within a pnemutic fastener generates the desired hammering force by employing compressed air (typically supplied by a separate air compressor), a valve assembly including a valve plunger, and a piston assembly including a sliding piston that drives a long blade. In such system, the piston is forced downward when the air pressure above the piston head is greater than below it. Moreover, the piston is forced into an “up” position when the air pressure below the piston is greater than above it. In addition, a trigger assembly is employed to allow a user to control the actuation of the pneumatic fastener.  
         [0004]     In use, the pneumatic fastener is actuated by a user activating the trigger assembly. Upon actuation, the trigger assembly closes the trigger valve while opening a passageway to the atmosphere as such compressed air is prevented from flowing above the valve plunger whereby pressure beneath the plunger is greater than pressure above the plunger. This configuration causes the valve plunger to rise up and compressed air to travel to the piston head. The piston and the blade are then driven downward by the compressed air causing a fastener (e.g. a nail or staple) to be propelled from the chamber. The downward sliding of the piston, in turn, channels the air inside the cylinder through a series of holes into a return air chamber. When a user then releases the trigger assembly, the plunger is pushed back into place by the compressed air and air flow to the piston head is blocked. In the absence of downward pressure, the piston head is also pushed back up by the compressed air in the return air chamber. As a result, the air above the piston head is forced out of the gun and into the atmosphere.  
         [0005]     Although the standard pneumatic fastener, such as a nailer, works well for driving even thick nails through hard material such fasteners are disadvantageous in many respects. First, the standard pneumatic fastener typically employs functional features for controlling and directing air flow which involve expensive and time consuming manufacturing processes and result in decreased performance characteristics. For example, many pneumatic fasteners require a cross hole to be drilled and plugged through an outer cap or an angled hole to be drilled through such cap in order to get supply air from the air source, through the outer cap and to the back side of the valve piston chamber. One disadvantage associated with this design is possible significant increases in manufacturing costs, which in turn may be passed onto the consumer. An additional disadvantage associated with such configuration is that employment of machined holes provide rough surfaces (e.g. edges) over which the air must travel. The rough surfaces may increase air flow turbulence/friction thereby reducing the efficiency of air flow travel and possibly decreasing the efficiency of the pneumatic fastener. Current solutions to overcome increased friction typically involve the application of a lubricant to the rough surfaces. Utilization of such lubricants may increase the cost of operating pneumatic fasteners while also possibly simultaneously resulting in decreased productivity as the pneumatic fasteners must halt operation in order to have the lubricant provided. In addition, the aforementioned disadvantage is continuous for the lubricant has a limited useful lifespan and must be continuously replaced to assist in smoothing the surfaces over which the air must travel.  
         [0006]     Therefore, it would be desirable to provide a pneumatic fastener which requires neither the machining of the outer cap to establish air flow patterns nor application of a lubricant to prevent increases in air flow friction.  
       SUMMARY OF THE INVENTION  
       [0007]     Accordingly, in a first aspect of the present invention a head valve assembly for a pneumatic fastener including a piston assembly reciprocated within a cylinder assembly for driving a fastener and a housing having an end cap for at least partially enclosing the head valve assembly is provided. In an exemplary embodiment, the head valve assembly includes a valve piston for causing supply pressure to be ported to the piston assembly for moving the piston assembly within the cylinder assembly from a non-actuated position to an actuated position for driving the fastener. Further, an inner cap is disposed within the end cap around the valve piston. The inner cap includes an inlet port for porting pressure to the valve piston. In addition, a main seal is coupled to the valve piston for sealing the cylinder assembly from supply pressure while pressure is ported to the valve piston by the inner cap for holding the piston assembly in the non-actuated position. The main seal seals pressure ported to the valve piston by the inner cap from supply pressure ported to the piston assembly.  
         [0008]     In specific embodiments of the instant head valve assembly, the inner cap may further include an exhaust port for porting exhaust from the head valve assembly. Further, the inner cap may be formed of a lubricious plastic. In additional embodiments, the main seal includes a lip seal for forming a seal with the inner cap and may provide shock absorption to the piston assembly. In further embodiments, the main seal may be coupled to the valve piston by a snap-lock mechanism. In such embodiment, the main seal may include a plurality of legs while the valve piston may include a plurality of leg receivers for coupling the main seal to the valve piston. For example, the snap-lock assembly comprises a plurality of legs extending from the main seal and a plurality of leg receivers disposed in an inner surface of the valve piston, each of the plurality of legs being received in a corresponding one of the plurality of leg receivers for coupling the main seal to the valve piston. In such embodiment, the piston assembly may include a projection, the plurality of legs for receiving and retaining the projection upon return of the piston assembly from the actuated position to the non-actuated position. In further exemplary embodiments, a lip seal is disposed between the valve piston and the inner cap.  
         [0009]     In additional specific embodiments of the head valve assembly, a compression spring may be employed for biasing the valve piston toward the piston assembly and causing the main seal to seal the cylinder assembly from supply pressure. For instance, the compression spring may trap the plurality of legs for preventing the main seal from separating from the piston valve by the piston assembly as the piston assembly moves from the non-actuated position to the actuated position. It is contemplated that the present head valve assembly may be coupled to various types of pneumatic fasteners including a pneumatic nailer and a pneumatic stapler.  
         [0010]     In an additional exemplary aspect of the present invention, a fastener device including dual actuation mode capability is disclosed. The apparatus of the present invention permits a user to select between a contact actuation mode in-which a user pulls or draws a trigger and actuation of the fastener device is initiated by a contact safety assembly and a sequential actuation mode in-which the contact safety assembly is depressed first and the trigger initiates actuation of the fastening event. The fastener device includes a sliding contact safety assembly which is configured to reciprocate towards/away from a driver housing. The contact safety assembly includes a contact member for contacting a workpiece. A rotating rod is pivotally operable with respect to an intermediate linkage. A pivot pin may be attached to the intermediate linkage. The rotating rod may include a recess for receiving the pivot pin. The pivot pin is configured with a first shoulder or ledge and a second shoulder which is off-set from the first shoulder. The second shoulder is further away from an end of the rod, opposite the linkage, than the second shoulder. The rod may be rotated to orientate either the first or the second shoulders toward a trigger assembly. The trigger assembly is pivotally coupled, via a pivot pin, to the driver housing. Trigger assembly is constructed so that a portion of the trigger contacts with the selected shoulder on the rotating rod so that the rod acts a stop for the trigger. A trigger lever is preferably included for actuating a valve or the like for permitting compressed air (in the case of a pneumatic fastener) to enter a driver chamber for forcing a piston with a driver blade attached thereto to secure a fastener. A toggle switch may be included to engaged with the rod to allow for efficient rotation. Preferably, a toggle switch is configured to remain in a fixed position while the contact safety assembly slides.  
         [0011]     In a further aspect, a depth adjustment system is included to permit varying the depth to which a fastener to be secured will be driven. In this aspect of the invention, a threaded thumb wheel is included to engage with a threaded portion of a pivot pin included on the intermediate linkage. A washer, biased into engagement with the thumb wheel, having a series of detents is included to secure the thumb wheel in the desired position along the pivot pin. The thumb wheel may be manipulated to increase or decrease the overall length of the contact safety system thereby varying the extent to which a fastener will be driven into a workpiece.  
         [0012]     In a further exemplary aspect of the present invention, an adjustable handle exhaust assembly is provided. The adjustable handle exhaust assembly includes a base, which includes a base plate and a protrusion protruding from the base plate. The protrusion is centrally hollow and includes an inner surface and an outer surface. The base plate includes an inlet opening and an exhaust opening defined therethrough. The inlet opening is interconnected with a channel defined by the inner surface of the protrusion. A cap is coupled to and supported by the base and includes an exit opening. A quick connector coupler is positioned inside the channel defined by the inner surface of the protrusion. When coupled to a pneumatic fastener, the quick connector coupler is suitable for connecting to an air supply hose to input compressed air to the pneumatic fastener via the channel defined by the inner surface of the protrusion and the inlet opening, and exhaust from the pneumatic fastener may exit through the exhaust opening and the exit opening.  
         [0013]     In a still further exemplary aspect of the present invention, a pneumatic fastener is provided. The pneumatic fastener includes a handle which includes an inlet channel and an outlet channel. An adjustable handle exhaust assembly is coupled to the handle for connecting to an air supply hose to input compressed air to the pneumatic fastener via the inlet channel and outputting exhaust of the pneumatic fastener via the outlet channel to outside. The adjustable handle exhaust assembly includes a base, a cap and a quick connector coupler. The base includes a base plate and a protrusion protruding from the base plate. The protrusion is centrally hollow and includes an inner surface and an outer surface. The base plate includes an inlet opening and an exhaust opening defined therethrough. The inlet opening is interconnected with a channel defined by the inner surface of the protrusion. The cap is coupled to and supported by the base and includes an exit opening. The quick connector coupler is positioned inside the channel defined by the inner surface of the protrusion. The quick connector coupler is suitable for connecting to the air supply hose to input the compressed air to the pneumatic fastener via the channel defined by the inner surface of the protrusion, the inlet opening, and the inlet channel, and the exhaust may exit through the outlet channel, the exhaust opening and the exit opening.  
         [0014]     In another exemplary aspect of the present invention, a handle for a pneumatic fastener is provided. The handle includes an inlet channel for inputting compressed air into the pneumatic fastener, an outlet channel for outputting exhaust of the pneumatic fastener to outside, and an adjustable handle exhaust assembly coupled to the handle. The adjustable handle exhaust assembly includes a base, a cap, and a quick connector coupler. The base includes a base plate and a protrusion protruding from the base plate. The protrusion is centrally hollow and includes an inner surface and an outer surface. The base plate includes an inlet opening and an exhaust opening defined therethrough. The inlet opening is interconnected with a channel defined by the inner surface of the protrusion. The cap is coupled to and supported by the base and includes an exit opening. The quick connector coupler is positioned inside the channel defined by the inner surface of the protrusion. The quick connector coupler is suitable for connecting to an air supply hose to input the compressed air to the pneumatic fastener via the channel defined by the inner surface of the protrusion, the inlet opening, and the inlet channel, and the exhaust may exit through the outlet channel, the exhaust opening and the exit opening.  
         [0015]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which:  
         [0017]      FIG. 1  is an illustration of a pneumatic fastener in accordance with an exemplary embodiment of the present invention;  
         [0018]      FIG. 2  is an exploded view of the pneumatic fastener including a head valve assembly coupled with a piston assembly in accordance with an exemplary embodiment of the present invention;  
         [0019]      FIG. 3  is a cut away view of a handle of the pneumatic fastener including a handle adapter coupled with an inlet channel and an exhaust channel coupled with a handle exhaust;  
         [0020]      FIG. 4  is an illustration of the head valve assembly, the inner cap having an inner diameter coupled with a main seal and valve piston;  
         [0021]      FIG. 5  is an illustration of the main seal connected with the valve piston through use of a snap lock mechanism;  
         [0022]      FIG. 6  is an isometric illustration of the head valve assembly coupled with a housing and a cap of the pneumatic fastener, wherein the head valve assembly at least partially occupies a fully defined recessed area of the pneumatic fastener;  
         [0023]      FIG. 7  is an isometric illustration of the housing including a housing inlet port and a housing outlet port;  
         [0024]      FIG. 8  is a cross-sectional view of the pneumatic fastener including the head valve assembly coupled with the piston assembly and the housing, the main seal and valve piston shown in a down position relative to the inner cap of the head valve assembly, in accordance with an exemplary embodiment of the present invention;  
         [0025]      FIG. 9  is an expanded cross-sectional view of the pneumatic fastener wherein the main seal and valve piston are shown in an up position relative to the inner cap of the head valve assembly;  
         [0026]      FIG. 10  illustrates the head valve assembly of the present invention employing a diaphragm coupled with the inner diameter of the inner cap;  
         [0027]      FIG. 11  is a partial side view illustration of a pneumatic fastener including a dual actuation mode assembly;  
         [0028]      FIG. 12  is an exploded view of the contact safety illustrated in  FIG. 11 ;  
         [0029]      FIG. 13A  is a cut-away side view of a dual actuation mode assembly;  
         [0030]      FIG. 13B  is a cut-away side view of the dual actuation mode assembly illustrating a rotating rod in contact actuation mode;  
         [0031]      FIG. 13C  is a cut-away side view of the dual actuation mode assembly illustrating a rotating rod in sequential actuation mode;  
         [0032]      FIG. 14  is an illustration of an adjustable handle exhaust assembly for use with a pneumatic fastener; and  
         [0033]      FIG. 15  is an exploded view of the adjustable handle exhaust assembly. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]     Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.  
         [0035]     Referring now to  FIG. 1 , an exemplary embodiment of a pneumatic fastener  100  in accordance with the present invention is provided. In the exemplary embodiment, the pneumatic fastener  100  includes a handle  102  having a first end  103  and a second end  105 . In the present embodiment, a housing  104  is coupled with the first end  103  of the handle  102 . The handle  102  further includes a handle adapter  156 , which enables the coupling of a compressed air supply to the pneumatic fastener  100 . In addition, a trigger assembly  108  for controlling the firing of the pneumatic fastener  100  may be coupled with the handle  102 , proximal to the first end  103 .  
         [0036]     Referring now to  FIG. 2 , in the exemplary embodiment the housing  104  defines a housing recessed area  125  within which a piston assembly including a cylinder  130  and a piston  134  may be mounted. The cylinder  130  is slidably coupled with the piston  134  which includes a piston projection  136 . It is understood that the piston  134  may operationally engage a driver blade for driving a fastener by providing force to the driver blade. The piston projection  136 , in the current embodiment, is enabled in a generally cylindrical shape. Alternatively, the piston projection  136  may be configured in various shapes, such as rectangular, spherical, and the like.  
         [0037]     In an exemplary embodiment, the housing  104  includes a first end  107  and a second end  109 . The first end of the housing  107  may couple with various mechanical devices to enable the functionality of the nailer, such as a nose casting assembly, which may enable the operation of the driver blade. The second end  109  of the housing  104  includes a first housing fastening point  110 , a second housing fastening  111 , a third housing fastening point  112 , and a fourth housing fastening point  113 . In an advantageous embodiment, the fastening points allow the coupling of an outer cap  114  with the second end  109  of the housing  104 . It is understood that the outer cap  114  may be composed of various materials, such as aluminum, steel, plastic, and the like. The fastening points may enable the use of a variety of fasteners. Suitable fasteners may include a screw, bolt, clip, pin, and the like. In the current embodiment, the cap  114  includes a first cap fastening point  115 , a second cap fastening point  116 , a third cap fastening point  117 , and a fourth cap fastening point  118 . The cap fastening points align with the housing fastening points to enable the fasteners to engage with the housing  104  and the cap  114  thereby securely affixing their position relative to one another.  
         [0038]     In the exemplary embodiment, the housing recessed area  125  is defined on one end by the first end  107  of the housing  104  and on the other end by the second end  109  of the housing  104 . The cap  114  further defines an outer cap recessed area  119 . When the cap  114  is coupled with the housing  104 , a fully defined recessed area  129  (as illustrated in  FIG. 6 ), of the pneumatic fastener  100  is established. It is understood that various configurations of the housing  104  and the cap  114  may define variously configured recessed areas  129 . It is contemplated that the configurations of the housing  104  and the cap  114  may partially encompass the recessed area  129 . Further, the housing  104  and the cap  114  may be configured for aesthetic and/or functional purposes. For example, contouring may establish the housing  104  and the cap  114  with an advantageous appearance, which may also provide for increased functionality by providing a contoured grip region. Still further, grip regions may be established with material for grasping engagement by the hand of the user of the pneumatic fastener  100 , including soft grips and the like.  
         [0039]     As illustrated in  FIG. 2 , the housing  104  may further define an inlet (supply) port  121  and an outlet (exhaust) port  123 . The configuration of the housing inlet port  121  and the housing outlet port  123  may vary. In a preferred embodiment, the housing inlet port  121  is of a generally cylindrically shaped conduit extending through the housing  104  while the housing outlet port  123  is of a generally rectangularly shaped conduit extending through the housing  104 . It is understood that the shape and/or configuration of the housing inlet and outlet ports may be varied as contemplated by those of ordinary skill in the art. For instance, the diameter of the housing inlet port  121  may be increased or decreased to alter the characteristics of the supply pressure. As shown in  FIG. 3 , the housing inlet port  121  acts as a conduit for the supply of compressed air coming through the inlet channel  126  via the handle adapter  156  connection. In addition, the housing outlet port  123  acts as a conduit for the air exhausted after the firing of the pneumatic fastener, directing the exhaust to the outlet channel  128  and then through a handle exhaust  158  of the handle  102 .  
         [0040]     In further exemplary embodiments, as illustrated in  FIG. 2 , the pneumatic fastener  100  includes a head valve assembly with an inner cap  150  for directing the flow of air to and from the piston  134  of the piston assembly of the fastener  100 . In an exemplary embodiment, a basket  132  is included within the inner cap  150  for stabilizing the piston  134 . In an alternative embodiment, the basket  132  is not included within the inner cap  150 , but directly seated upon the cylinder  130 .  
         [0041]     In the present exemplary embodiment, the head valve assembly at least partially occupies the recessed area  129 . Further, a main seal  142  is adjustably coupled with an inner diameter  151  of the inner cap  150 . The main seal  142  is further coupled with the piston  134  and a valve piston  144 . In a preferred embodiment, the main seal  142  is seated upon the piston  134 . This coupling allows the main seal  142  to provide shock-absorption to the piston  134  of the pneumatic fastener  100 . The main seal  142 , in a preferred embodiment, may be composed of a urethane material. Alternative materials, such as other plastics, metals, and the like, may be employed as contemplated by those of skill in the art which include the desired durability. Additionally, in such advantageous embodiment, the valve piston  144  is composed of a plastic material. It is further preferred that the plastic be an acetal which includes compounds that are characterized by the groupig C(OR) 2 , such as Delrin®, a registered trademark owned by the E.I. du Pont de Nemours and Company. Such composition provides the valve piston  144  with a reduced frictional coefficient while still enabling a secure coupling with the main seal  142 .  
         [0042]     As further illustrated in  FIG. 2 , in an exemplary embodiment, an O-ring gasket  190  connects the top side  180 , of the inner cap  150 , with an inner wall  120  of the cap recessed area  119  of the aluminum cap  114 . The O-ring gasket  190  provides a seal between the aluminum cap  114  and the inner cap  150 . It is understood that the O-ring gasket  190  may enable various degrees of stretching and/or deflecting depending on the materials used to establish the O-ring gasket  190 . This seal assists in directing the air flow provided into and out of the head valve assembly  140  via the inner cap inlet conduit  182  and the inner cap outlet conduit  184 . In a preferred embodiment, the O-ring gasket  190  may nest in a groove established in the inner wall  120  of the aluminum cap  114 . In an alternative embodiment, the O-ring gasket  190  may nest in a groove established in the top side  180  of the inner cap  150 . It is further contemplated that the O-ring gasket  190  may be integrated with either the inner wall  120  of the aluminum cap  114  or the top side  180  of the inner cap  150 .  
         [0043]     As illustrated in  FIG.4 , the inner cap  150  is further comprised of an inner cap exhaust conduit  184 . The inner cap outlet conduit  184  directs the flow of exhausted air to the housing outlet port  123 , established in the second end  109 , of the housing  104 , which is connected to the exhaust channel  128  within the handle  102 . Thus, the exhausted air is removed from the head valve assembly  140  via the inner cap  150 .  
         [0044]     It is contemplated that the coupling of the main seal  142  with the piston  134  may be accomplished in a variety of ways. For example, in an exemplary embodiment, the main seal  142  is coupled with the valve piston  144  via a snap lock mechanism. In an advantageous embodiment, as illustrated in  FIGS. 4 and 5 , the snap lock mechanism is enabled by a first leg  160 , a second leg  162 , and a third leg  164  which are connected to the main seal  142 . In configuration, the legs  160  through  164  generally extend from the main seal  142  and include a tapered undercut on a flange included within each of the three legs. Further, on the end opposite the connection to the main seal  142 , each leg terminates in a tab, which generally extends from the leg. The legs are formed about a piston projection receiving point  166 . In the current embodiment, the piston projection receiving point  166  is an aperture, which extends through the main seal  142 .  
         [0045]     As illustrated in  FIG. 5 , in an exemplary embodiment, the legs  160  through  164  of the main seal  142  couple with a first leg receiver  172 , a second leg receiver  174 , and a third leg receiver  176 , respectively. In the present embodiment, the leg receivers are disposed within a valve piston inner diameter of the valve piston  144 . In a preferred embodiment, the three leg receivers are established by a ledge  171 . In such embodiment, the ledge  171  includes three grooves for receiving the three legs of the main seal  142 . In an alternative embodiment, the three leg receivers may be established as pockets disposed within the inner diameter of the valve piston  144 . The three leg receivers  172  through  176  are configured with a matching profile to that of the three legs  160  through  164 .  
         [0046]     In operation, the three legs of the main seal  142  may be inserted within the three leg receivers of the valve piston  144 . Upon being fully inserted, the tabs formed at the terminus of each leg may snap into place with respect to the leg receivers. The snapping into place may be accomplished in a variety of manners. In the present example, the material composition and configuration of the legs provide the force which snaps the tabs into place. The tabs assist in securing the position of the main seal  142  relative to the valve piston  144  by coupling the tabs against the valve piston  144 . In alternative embodiments, the snap mechanism may be enabled as a spring loaded assembly and the like as contemplated by those of ordinary skill in the art. It is further contemplated that the main seal  142  and the valve piston  144  may be an integrated single unit.  
         [0047]     In further exemplary embodiments, a secondary coupling of the valve piston  144  with the main seal  142  occurs via a tongue and groove assembly. The valve piston  144  includes a tongue member disposed about the circumference of a bottom edge of the valve piston  144 . In a corresponding circumferential position on the main seal  142 , a groove is established. Thus, when the main seal  142  is coupled with the valve piston  144 , via insertion of the plurality of legs into the plurality of leg receivers, the tongue is inserted within the groove to provide secondary coupling support. It is contemplated that the secondary coupling characteristics may be provided through various alternative mechanisms. For example, the secondary coupling may be established by employing a friction lock mechanism, a compression lock mechanism, a latch mechanism, and the like, without departing from the scope and spirit of the present invention.  
         [0048]     As illustrated in  FIG. 6 , in an exemplary embodiment, the piston projection receiving point  166  is configured to receive the piston projection  136 . Therefore, as the configuration of the piston projection  136  is altered so to may the piston projection receiving point  166  and the three legs  160 ,  162 , and  164  be altered to accommodate this change. The three legs  160  through  164 , in a preferred embodiment, are enabled to trap and hold the piston projection  136  when extended through the piston projection receiving point  166 .  
         [0049]     The securing of the piston projection  136  by the three legs may be accomplished using various mechanisms. In a preferred embodiment, the three legs serve as a piston catch by providing a friction fit for engaging against the piston projection  136 . Alternatively, the enabling of the piston catch may occur through the use of compression assemblies, ball joint assemblies, and the like. It is understood that the three legs trap and hold the piston projection  136  when the piston  134  is established in an “up” position (as illustrated in  FIG. 9 ). It is further contemplated that the cylinder  130  may include a counter bore to further assist in maintaining the piston in the “up” position. The “up” position is the pre-fire position or the position the piston  134  returns to after the pneumatic fastener  100  has fired, using the compressed air to drive the piston  134  into a “down” position (as illustrated in  FIG. 8 ). The “down” position provides the force for driving the driver blade through the nose casting, engaging with a nail located within the nose casting, and driving the nail into a surface against which the nose casting is set. The piston catch established by the present invention may provide increased efficiency by reducing any unwanted travel by the piston  134  towards the “down” position when the pneumatic fastener  100  is not being fired. For instance, when the pneumatic fastener  100  is set in a position to fire the user may tap the surface, inadvertently, being operated upon with the gun. This tap may result in the piston  134  traveling towards the “down” position. This travel may reduce the operational effectiveness of the pneumatic fastener  100  by limiting the range of travel of the piston  134  during firing of the gun  100 , thereby, limiting the force provided by the piston  134  in driving the fastener, such as the nail, by the pneumatic fastener  100 . This limited force may result in the fastener failing to reach the desired depth, such as by not recessing properly, which may have the effect of requiring additional time spent to accomplish a task. This may limit productivity and increase expenses associated with completing the task.  
         [0050]     In an exemplary embodiment, as illustrated in  FIGS. 8 and 9 , a compression spring  148  is coupled against a bumper seal  152  on one end and the three legs  160 ,  162 , and  164 , snapped in position relative to the valve piston  144 , on the opposite end. In the exemplary embodiment, the compression spring  148  extends through a spring receiving point  181  (as shown in  FIG. 4 ) of the inner cap  150 . In the current embodiment, as shown in  FIG. 4 , the spring receiving point  181  is an aperture through a top side  180  of the inner cap  150 . The coupling against the three legs snapped into position relative to the valve piston  144  enables the compression spring  148  to “trap” the legs (as illustrated in  FIG. 9 ), thereby, assisting in preventing the main seal  142  from being pulled away from the valve piston  144  by the piston  134  when fired.  
         [0051]     The functionality of the compression spring  148  in combination with the snap fit of the main seal  142  with the valve piston  144  assists in enabling the main seal  142  to establish and maintain a seal between the supply pressure and the pressure behind the valve piston  144 . In the current embodiment, the main seal  142  includes a main lip seal  143  to further assist in providing the above mentioned functionality. The main lip seal  143  further enables the main seal  142  to slidably couple with the inner diameter  151  of the inner cap  150 . Thus, the main lip seal  143  enables the main seal  142  to travel within the inner cap  150  and maintain the seal between the supply pressure and the pressure behind the valve piston  144 . It is understood, that the travel of the main seal  142  translates into a travel of the valve piston  144 , within the inner cap  150 , and the compression or extension of the compression spring  148 . A secondary lip seal  146  is set upon the valve piston  144 . The secondary lip seal  146  is set on the side opposite the coupling of the main seal  142  against the valve piston  144 . The secondary lip seal  146  may assist in providing a seal between the valve piston  144  and the inner cap  150 .  
         [0052]     It is contemplated that the inner cap  150  may be composed of various materials. For example, the inner cap  150  may be composed of Delrin®, a registered trademark owned by the E.I. du Pont de Nemours and Company. A composition including Delrin® is advantageous for Delrin® is an acetal which is a lubricious plastic providing a surface which may reduce the amount of turbulence/friction involved with the travel of the compressed air into or out of the head valve assembly  140  of the present invention. Further, the use of Delrin® for the valve piston  144 , as stated previously, may reduce the amount of turbulence/friction encountered by the valve piston  144  during travel of the valve piston  144  within the inner diameter  151  of the inner cap  150 . The materials used for the inner cap  150  may further comprise alternative plastics, Teflon® (a registered trademark of DuPont), silicone, and the like. While the present invention is enabled with the inner cap  150 , which directs the air flow into and out of the head valve assembly  140  without requiring lubricants to be added, it is contemplated that various lubricants may be used in conjunction with the present invention. Lubricants, such as Teflon® based lubricants, silicone based lubricants, and aluminum disulfide based lubricants may be employed without departing from the scope and spirit of the present invention.  
         [0053]     In an alternative embodiment, the main seal  142  and valve piston  144  may be replaced by a diaphragm  198 , as illustrated in  FIG. 10 . The diaphragm  198  provides the functionality of the main seal  142  coupled with the inner diameter  151  of the inner cap  150 , of the head valve assembly  140 . The diaphragm may also couple with the cylinder  130 , at least partially surrounding the cylinder  134 . The diaphragm may be composed of various materials, which provide various degrees of stretching and/or deflecting of the diaphragm. This stretching and/or deflecting may translate into movement by the diaphragm  198  within the inner diameter  151 . As previously stated, this may further translate into the extension and/or compression of the compression spring  148 . It is still further contemplated that the use of the diaphragm  198  may eliminate the need for the compression spring  148 . It is understood that the configuration of the diaphragm  198  may be altered to accommodate the needs of the manufacturer, consumer, or those of ordinary skill in the relevant art. It is further contemplated that the diaphragm  198  may be employed in conjunction with the main seal  142  and the valve piston  144 . The diaphragm  198  may couple with the main seal  142  and any stretching/deflecting of the diaphragm  198  within the inner diameter  151  of the inner cap  150  may translate into movement of the main seal  142  and valve piston  144  within the inner diameter  151 .  
         [0054]     During use, compressed air travels through the inner cap  150  and into the head valve assembly  140  via an inner cap inlet conduit  182 . The inner cap inlet conduit  182  establishes an air flow pattern through the inner cap  150  from the inlet channel  126  of the handle  102 . The housing inlet port  121 , established on the second end  109  of the housing  104 , enables the compressed air being provided through the inlet channel  126 , to flow into the inner cap inlet conduit  182 . The compressed air supplied through the inner cap inlet conduit  182  enables the head valve assembly  140  to operate the pneumatic fastener  100 , i.e., the firing of the piston  134  to drive the fastener into a surface or work piece.  
         [0055]     Referring to  FIGS. 11-13C , a pneumatic fastener  1100  including a dual actuation mode assembly  1102  is discussed. Those of skill in the art will appreciate that while a pneumatic fastener is discussed, the principles of the present invention may equally apply to devices utilizing a combustion event or a detonation event to secure a fastener such as a nail, a staple, or the like. The dual actuation mode assembly  1102  permits user selection of the type of actuation the fastener device is to operate (e.g. in a contact fire mode or sequential actuation mode). In contact actuation mode, a user pulls (and holds) the trigger  1104  and subsequently the contact safety assembly  1106  is depressed or pushed inwardly toward a driver housing  1108  thereby activating a pneumatic valve  1109  for releasing compressed air to drive a piston and driver into contact with a nail or fastener disposed in the driver&#39;s path of travel. Subsequent fastening events, in contact actuation mode, may be initiated by movement of the contact safety towards the driver housing such as when the pneumatic fastener  1100  has been repositioned and pressed against a workpiece. In sequential fire mode, the contact safety assembly is depressed toward the driver housing and subsequently the trigger is pulled to initiate a fastening event (the driving of a nail, staple or the like).  
         [0056]     With particular reference to  FIGS. 11 and 12 , the pneumatic fastener  1100  includes the driver housing  1108  for housing a reciprocating piston including a driver blade attached thereto for driving a fastener disposed within the path of travel of the driver blade. A contact safety assembly  1106  is adjustably mounted to the driver housing  108  in order to permit the contact safety assembly to slide towards and away from to the driver housing/the nose  1110  of the driver housing. In various embodiments, the nose may be formed as a separate structure or may be integrally formed with the main portion of the driver housing  1108 . Preferably, the contact safety assembly  1106  is biased, such as by a main spring or the like, into a remote position or away from the nose  1110  of the driver housing. Biasing the contact safety assembly away from the main portion of the fastener permits the contact safety system to function as a lock-out mechanism so that the pneumatic fastener cannot actuate. Additionally, as described above, the contact safety assembly  1106  may be utilized to initiate a fastening event (in contact mode).  
         [0057]     The contact safety assembly  1106  includes a contact pad  1114  or foot for contacting with a workpiece. Additionally, a no-mar tip may be releasably connected to the contact pad for preventing marring of the workpiece, if the contact pad is formed of metal or includes a serrated edge for engaging a workpiece (such as in a framing nailer). For example, the contact pad  1114  may be shaped so as to translate or slide along the nose  1110  of the driver housing  1108 . In the present embodiment, the contact pad  1114  is generally shaped as a hollow cylindrical structure for sliding along the generally cylindrical nose. An intermediate linkage  1116  is coupled to the contact pad  1114  to generally position a cylindrical rod  1118  along the driver housing  1108 . For example, the movement of the intermediate linkage may permit the cylindrical rod  1118  to be variously positioned with respect to the driver housing  1108  and thus, a trigger assembly which is  1104  pivotally mounted to the driver housing  1108  and/or a handle  1120  fixedly secured to the driver housing  1108 . In the current embodiment, the intermediate linkage  1116  is secured via a fastener to the contact pad  1114 . In further embodiments, the contact pad and linkage may be unitary. In the present example, the intermediate linkage is constructed in a general L-shape to position the rod  1118  adjacent the trigger (i.e., towards the handle  1120 ). Additionally, the intermediate linkage may be constructed so as to generally conform to the driver housing, to avoid other pneumatic fastener components, i.e, avoid fastener magazine components, for aesthetic purposes or the like. Moreover, in the present instance, the intermediate linkage  1116  includes a pivot pin  1122  coupled to an end of the linakge  1116 . The pivot pin  1122  may be secured via a fastener, a friction fit or unitarily formed with the intermediate linkage. In the present embodiment, the pivot pin  1122  is received in an aperture defined in a tab which extends generally perpendicular to a leg of the generally L-shaped linkage. A portion of the pivot pin  1122  may be received in a corresponding cylindrical recess formed in the rod  1118  for at least partially supporting/pivotally connecting the rod  1118  to the intermediate linkage via the pivot pin  1122 .  
         [0058]     Referring to  FIGS. 12 and 13 A, in an additional aspect of the present invention, the contact safety assembly  1106  includes an optional depth of drive or recess adjustment capability. A depth adjustment system permits a user to select to what extent the fastener is to be driven into the workpiece via selecting the extent to which the contact safety extends towards/away from the driver housing. Those of skill in the art will appreciate that a variety of factors will influence the depth to which a fastener will be driven. For example, a user may wish to leave the head of a nail above the surface of the workpiece (i.e. leave the nail proud) or may select to recess the nail head into the workpiece such that putty or filler may be filled into the recess thereby covering over the nail head (e.g., when building cabinetry or the like). In the present instance, the pivot pin  1122  includes a threaded portion  1124  or section for threading with a thumb wheel  1126 . A thumb wheel  1126  includes a corresponding aperture having a threaded portion  1130  such that the thumb wheel  1126  may travel along the threaded length of the pivot pin  1122 . The thumb wheel thereby may extend the overall length of the contact safety assembly and thus, vary the depth to which a fastener may be driven through interaction with the pneumatic valve  1109  for controlling the flow of compressed air into the driver cylinder. In the foregoing example, the thumb wheel  1126  may frictionally interconnect with a washer  1128 , disposed between the thumb wheel  1126  and a lip/flange  1134  included on the rod, via a series of rib/grooves, detents and protrusions or the like. It is to be appreciated that the rod  1118  is permitted to freely pivot (e.g., not in threaded engagement) about the pivot pin  1122 . For example, the rod  1118  and thus, the washer  1128  may be biased such as via a spring  1132  towards or into engagement with the thumb wheel  1126 . Preferably, the washer  1128  may be geometrically shaped or include protrusions such that the washer  1128  does not rotate with the thumb wheel  1126 , e.g., remains in a fixed orientation with respect to the driver housing and/or a secondary housing or contact safety housing  1136  coupled to the driver housing for at least partially encompassing at least a portion of the contact safety assembly. The series of protrusions/detents may act to retain the thumb wheel  1126  in a desired position along the pivot pin  1122 . Those of skill in the art will appreciate that the depth adjustment mechanism may be formed with a threaded projection in threaded connection with an end of a rod so as to effectively extend/retract the overall length of the rod. In the previous example, the projection is received in a recess formed in an intermediate linkage such as a tab included on an end of the linkage. For example, a rod may include a threaded portion along which a thumb wheel is in threaded engagement while the terminal portion of the rod is inserted in an aperture in an intermediate linkage.  
         [0059]     In further embodiments, a depth of drive mechanism may be disposed between the contact pad  1114  and an intermediate linkage  1116 . Additionally, if a depth of drive or recess adjustment is not desired, the rod  1118  may extend into a recess or aperture included in a tab extending from an end of an intermediate linkage. In still further embodiments, a partially threaded pivot pin may be threaded into an aperture in the intermediate linkage and function as a pivot pin for the rod  1118 . Alternatively, a rod may include an extension which may be received in an aperture in the intermediate linkage for achieving substantially the same functionality.  
         [0060]     With particular reference to  FIGS. 12 and 13 A-C, the rod  1118  includes a first shoulder  1146  and a second shoulder  1148 . The first and the second shoulders are formed at offset distances along the length of the rod  1118  such that the orientation of a trigger  1152  and thus, a trigger lever  1142  pivotally coupled via a trigger lever pivot pin  1140  to the trigger may be varied. For example, the orientation/lateral position of the trigger lever  1142  permits selecting contact actuation mode (as illustrated in  FIG. 13B ) when the first shoulder  1146  is orientated or rotated towards the trigger  1152 . While sequential actuation (as observed in  FIG. 13C )  1148  is achieved when a second shoulder which is further from the terminal end of the rod  1118  than the first shoulder  1146  is orientated or rotated towards the trigger  1152 . The particular actuation mode selected (i.e., contact actuation or sequential actuation) is determined by the change in orientation/lateral position of the trigger  1152 /trigger lever  1142  as the trigger assembly  1104  pivots about a trigger pivot pin  1156  and the selected shoulder contacts the trigger  1152 . For example, as the trigger  1152  pivots about the trigger pivot pin  1156  and contacts with the select shoulder, included on the rod, such that the shoulder acts as a stop against which the trigger  1152  is positioned. Those of skill in the art will appreciate that the interface of the rod/trigger is off-centered from the trigger pivot pin  1156  thereby varying the point (along the trigger lever  1142 ) at which the valve  1109  will contact the trigger lever  1142  due to the relative orientation/position of the trigger lever  1142 . In further embodiments, the trigger lever  1142 /trigger  1152  is biased away from the pneumatic valve  1109  by a spring  1154  or the like such that a user is required to overcome the biasing force to activate the valve  1109 . In the present embodiment, a central cylindrical projection extends beyond the first and the second shoulders  1146  and  1148 , respectively. In this instance, the trigger lever and trigger, such as the lipped portion of the trigger for engaging a shoulder, may include a curved recess to permit passage of the projection. The trigger lever  1142  may be configured to engage with the rod  1118  so as to prevent a repeated fastening event when sequential actuation or firing mode is selected. In further instances, the first and the second shoulders may be formed by milling flattened portions into a rod. Preferably, the shoulders are arranged at 180° (one hundred eighty degrees) from each other to permit sufficient engagement of the trigger and the selected shoulder.  
         [0061]     With continued reference to  FIGS. 11-13C , orientation of the rod  1118  may be achieved by rotating the rod  1118  such that a selected shoulder (the first shoulder  1146  or the second shoulder  1148 ) is aligned with a lip included on the trigger  1152 . A toggle lever or switch  1138  is coupled to the rod  1118 . In the present embodiment, the toggle switch  1138  is positioned below the trigger  1152  (with respect to the handle  1120 ) in order to permit a user to rotate the rod  1118  and thus, vary the pneumatic fastener&#39;s actuation mode by utilizing his/her forefinger and thumb. This positioning is additionally advantageous as a user may efficiently select between actuation modes without the complexity previously experienced. In the foregoing manner, a user may select between actuation modes more frequently thereby increasing efficiency over systems which require complex, time consuming manipulation. Preferably, the toggle switch defines an aperture through which the rod  1118  passes. In the present embodiment, a protrusion  1139  is formed by the toggle switch for extending into a keyway or channel extending longitudinally along at least a portion of the rod. In further embodiments, a setscrew may be utilized to accomplish this function. Those of skill in the art will appreciate a variety of mechanical interconnect systems may be implemented to achieve this function. For example, a portion of the rod may have a hexagonal cross section while a toggle switch includes a hexagonal aperture, a portion of the rod may be milled off or have a flattened portion or the like. Inclusion of a keyway or the like structure permits the toggle switch to remain in a fixed position (held in place via the contact safety housing  1136 ) with respect to the contact safety housing  1136 /the driver housing  1108  while the rod is permitted to variously position along the driver housing. Those of skill in the art will appreciate that the toggle may be fixedly secured to the rod as well so that the toggle switch travels with the rod  1118  as the contact safety assembly  1106  is manipulated generally along the driver housing.  
         [0062]     In further examples, the toggle switch  1138  may include a detent for engaging with the contact safety cover in order to frictionally secure the toggle switch in a desired orientation (i.e. contact actuation or sequential fire). Moreover, the toggle switch may include a cam shaped outer surface for frictionally engaging the contact safety housing to retain the toggle in a desired orientation. For example, a detent and/or cam surface may be included to secure the toggle switch in sequential fire mode. Those of skill in the art will appreciate that the lever portion of the toggle may act as an indicator or indicia of the selected actuation mode to permit ready recognition. Additional symbols or markings may be included on the driver housing, the contact safety housing or provided as an adhered label to one of the housing to alert the user as to the mode selected. Preferably, the toggle switch is orientated at 90° (ninety degrees) or perpendicular to a main axis of the trigger so that the selected contact mode is readily observed. For example, the toggle lever may be orientated approximately 180° (one hundred eighty degrees) when disposed in contact actuation mode than when disposed in sequential actuation mode.  
         [0063]     Referring now to  FIGS. 14 and 15 , an additional embodiment of the present invention is illustrated wherein an adjustable handle exhaust assembly  1400  (see  FIGS. 14 and 15 ) is provided. Such assembly  1400  may be coupled to a second end of a handle of a pneumatic fastener, such as a pneumatic nailer, to replace the handle exhaust  158  and handle adapter  156  as illustrated in  FIG. 3 . The adjustable handle exhaust assembly  1400  may be used to input compressed air into the inlet channel  126  and may enable an operator to direct the flow of exhaust coming from the outlet channel  128  in a desired direction (e.g., away from the operator). The exhaust assembly  1400  includes a base  1402 , which includes a base plate  1404  and a cylindrical and centrally hollow protrusion  1406  protruding from and normal to the base plate  1404 . Preferably, the base plate  1404  includes an inlet opening defined therethrough and includes a first portion  1408  and a second portion  1410 . Both portions  1408 ,  1410  have a circular shape and are attached to each other. The first portion  1408  is smaller than the second portion  1410 . That is, the diameter of the first portion  1408  is smaller than the diameter of the second portion  1410  so that a perimeter  1412  of the second portion  1410  is exposed for supporting a cap  1414 . The base plate  1404  includes a plurality of openings  1416  and an exhaust opening  1418  defined therethrough. A plurality of bolts  1420  may be inserted into the corresponding plurality of openings  1416  to securely couple the base  1402  to the second end  105  of the handle  102  of the pneumatic fastener  100 . The protrusion  1406  includes a threaded inner surface defining a channel for receiving a quick connector coupler  1422  and a partially threaded outer surface for receiving a compression ring  1426 . The channel defined by the threaded inner surface of the protrusion  1406  is interconnected with the inlet opening of the base plate  1404 . The cap  1414  may be made of metal, plastic, rubber, or the like. The cap  1414  includes an exit opening  1424  on its outer surface  1430  for letting the exhaust air exit the pneumatic fastener  100 . Preferably, the cap  1414  is donut-shaped with a central hole  1428  defined therein. The cap  1414  is placed on top of the base  1402  so that the protrusion  1406  protrudes from the central hole  1428  and the cap  1414  is supported by the perimeter  1412  of the second portion  1410 . Preferably, the cap  1414  is securely coupled to the base  1402  by the compression ring  1426  fastened on the partially threaded outer surface of the protrusion  1406  so that the exhaust inside the cap  1414  may exit to outside through the exit opening  1424 . The cap  1414  may be easily rotated to change the position of the exit opening  1424  whereby exhaust air exiting the exit opening  1424  can be directed in a desired direction (e.g., away from an operator).  
         [0064]     The adjustable handle exhaust assembly  1400  may be securely coupled to the second end  105  of the handle  102  of the pneumatic fastener  100  by the bolts  1420  to replace the handle adapter  156  and the handle exhaust  158 . Preferably, the inlet opening of the base plate  1404  is interconnected with the inlet channel  126 , and the exhaust opening  1418  is interconnected with the outlet channel  102 . The quick connector coupler  1422  is connected to an air supply hose for supplying compressed air to the pneumatic fastener  100 . The compressed air flows from the air supply hose into the inlet channel  126 , via the quick connector coupler  1422 , the channel defined by the threaded inner surface of the protrusion  1406 , and the inlet opening of the base plate  1404 . The exhaust in the outlet channel  128  flows into the cap  1414  via the exhaust opening  1418  and exits the cap  1414  via the exit opening  1424 . An operator may rotate the cap  1414  easily to change the position of the exit opening  1424  so that the exhaust air exiting the exit opening  1424  is directed in a desired direction (e.g., away from the operator).  
         [0065]     In a further exemplary embodiment directed to the present invention, a method of manufacturing a pneumatic fastener, such as the pneumatic fastener  100 , is provided. In a first step a housing including a piston assembly is provided. The housing may be of various configurations to support the functional operation of the pneumatic fastener and address aesthetic and/or ergonometric considerations. The housing is further provided with a housing inlet port and a housing exhaust port. The next step involves positioning a handle, including a handle adapter for receiving compressed air and a handle exhaust for exhausting the compressed air, to be coupled with the housing. The handle including an inlet channel coupled with the handle adapter and an outlet channel coupled with the handle exhaust. The inlet channel is further coupled with the housing inlet port and the outlet channel is further coupled with the housing exhaust port. Next, a head valve assembly including an inner cap of the present invention, is established in operational connection with the piston assembly. The inner cap further includes an inner cap inlet conduit which couples with the housing inlet port and an inner cap exhaust conduit which couples with the housing exhaust port. An outer cap is then fastened to the housing, the outer cap at least partially encompassing the head valve assembly and coupling with the inner cap.  
         [0066]     It is contemplated that the method manufacturing may further include the establishment of a groove into the outer cap. The groove being enabled to receive an O-ring gasket and for providing a seal between the outer cap and the inner cap. In an alternative embodiment, the method of manufacturing may include the establishment of a groove in the inner cap for receiving an O-ring gasket and establishing a seal between the outer cap and the inner cap.  
         [0067]     It is understood that the specific order or hierarchy of steps in the methods disclosed are examples of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the method can be rearranged while remaining within the scope and spirit of the present invention.  
         [0068]     It is believed that the present invention and many of its attendant advantages will be understood by the forgoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof. Further, it is to be understood that the claims included below are merely exemplary of the present invention and are not intended to limit the scope of coverage which has been enabled by the written description.