Patent Publication Number: US-2017361442-A1

Title: Feed Piston Pressure Tube

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a non-provisional application of and claims the benefit of the filing date of each of the following: copending U.S. provisional patent application No. 62/352,477 entitled “Connecting Tube” filed Jun. 20, 2016; copending U.S. provisional patent application No. 62/352,515 entitled “Cylindrical Combination Trigger/Head Valve” filed Jun. 20, 2016; copending U.S. provisional patent application No. 62/352,541 entitled “Depth Of Drive Mechanism” filed Jun. 20, 2016; and copending U.S. provisional patent application No. 62/352,547 entitled “Driver Blade” filed Jun. 20, 2016. 
    
    
     INCORPORATION BY REFERENCE 
     This patent application incorporates by reference in its entirety each of the following: copending U.S. provisional patent application No. 62/352,477 entitled “Connecting Tube” filed Jun. 20, 2016; copending U.S. provisional patent application No. 62/352,515 entitled “Cylindrical Combination Trigger/Head Valve” filed Jun. 20, 2016; copending U.S. provisional patent application No. 62/352,541 entitled “Depth Of Drive Mechanism” filed Jun. 20, 2016; copending U.S. provisional patent application No. 62/352,547 entitled “Driver Blade” filed Jun. 20, 2016; and copending U.S. patent application Ser. No. 15/627,450 entitled “Cylindrical Integrated Valve Assembly” filed Jun. 20, 2017. 
     FIELD OF THE INVENTION 
     The present invention generally relates to the field of pneumatic tools, and particularly to pneumatic fastening tools, such as pneumatic nailers and pneumatic staplers. 
     BACKGROUND OF THE INVENTION 
     Pneumatic fastening tools can have fastener drive systems which jam, are unreliable and have difficulty feeding fasteners to be driven into a workpiece. There is strong need for a pneumatic fastening tool with an improved and more reliable fastener feed and driving system. 
     SUMMARY OF THE INVENTION 
     In an embodiment, a pneumatic fastening device can have a chamber that provides a compressed air to a drive piston to drive a fastener, a feed piston which can feed a fastener into a drive channel; and a feed piston return chamber configured to receive a portion of the compressed air to move the feed piston in a direction away from the drive channel. The pneumatic fastening device can have a feed pawl that moves in concert with a movement of the feed piston. In an embodiment, the fastener can be a nail, or a staple, or other fastener. 
     In an embodiment, the pneumatic fastening device can have a means by which the compressed air can be fed to the feed piston return chamber. In non-limiting example, the means by which the compressed air can be fed to the feed piston return chamber can be a passageway, pipe, channel, opening, conduit or a feed piston pressure tube. The means by which the compressed air can be fed to the feed piston return chamber can be configured to transport pressurized the compressed air through at least one bulkhead member to a feed piston return chamber. 
     In an embodiment, a pneumatic fastening device can have a drive piston having a driver blade to drive a fastener into a workpiece, a nosepiece having a drive channel and a pressure reservoir chamber that provides a compressed air to the drive piston to drive the fastener. A feed piston can feed one or more fastener toward the drive channel when the drive piston is in a resting state. A feed piston return chamber can be configured to receive a portion of the compressed air to move the feed piston in a direction away from the drive channel. 
     In an embodiment, a pneumatic fastening device can have a pressure reservoir chamber configured to contain a compressed air and a feed piston return chamber that receives a portion of the compressed air. A plenum chamber can be separated from a feed piston return chamber. A feed piston pressure tube can be configured to pass through the plenum chamber and provide a compressed air from the pressure reservoir chamber to the feed piston return chamber. Optionally, an orifice having an orifice inlet and an orifice outlet that can have the compressed air fed to the orifice inlet, the compressed air can pass through the orifice and exit the orifice outlet to then be fed to the feed piston pressure tube. Optionally, the orifice can be an orifice bead having an orifice bead inlet, an orifice bead channel and an orifice bead outlet that can have the compressed air fed to the orifice bead inlet, the compressed air can pass through the orifice bead channel and exit the orifice bead outlet to then be fed to the feed piston pressure tube. 
     In an embodiment, the feed piston pressure tube can be configured to connect a feed inlet receiving the compressed air from the pressure reservoir chamber to a nose port through which the compressed air is fed to the feed piston return chamber. Optionally, the compressed air fed from the reservoir chamber has a pressure in a range of 70 psig to 500 psig. 
     In an embodiment, the pneumatic fastening device can have at least one bulkhead configured between the pressure reservoir chamber and the feed piston and the feed piston pressure tube can pass though the at least one bulkhead. For example, the pneumatic fastening device can have and over-piston chamber which has a reservoir bulkhead through which the feed piston pressure tube passes. In another example, For example, the pneumatic fastening device can have a plenum chamber that has a plenum bulkhead through which the feed piston pressure tube passes. In an embodiment, an over-piston chamber can be configured to provide the compressed air to the feed piston pressure tube. 
     In yet another example, the pneumatic fastening device can have a reservoir bulkhead configured between the over-piston chamber and the pressure reservoir chamber and a plenum bulkhead configured between the pressure reservoir chamber and the plenum chamber, in which the feed piston pressure tube can pass though the reservoir bulkhead and through the plenum bulkhead. 
     In an embodiment, the pneumatic fastening device can also have a feed piston, a feed pawl and a feed piston return chamber configured between the feed piston and the feed pawl and/or feed pawl head. The feed pawl can be configured to contact one or more of a fastener when in a resting state and a feed piston which controls the movement of the feed pawl. The feed piston pressure tube can be configured to provide a compressed air to the feed piston return chamber. In an embodiment, the In an embodiment, the pneumatic fastening device can have a feed piston return chamber that has a nose port and the feed piston pressure tube can be configured to provide the compressed air through a feed tube opening and into the feed piston return chamber through the nose port. The feed piston return chamber can have a nose port that is disposed between the pressure reservoir chamber and the feed piston. The feed piston pressure tube can be configured to provide the compressed air through a feed tube opening and into the feed piston return chamber through the nose port. A feed tube opening of the feed piston pressure tube can receives compressed air and can feed the compressed air to a feed piston through the nose port. The nose port is disposed between the feed piston and the feed pawl. The feed pawl can be configured to contact one or more of a fastener when in a resting state. The feed piston can be configured to drive the pawl which pushes one or more of a fastener. 
     In an embodiment, the pneumatic fastening device can have a feed tube opening, a feed piston biased by a feed spring, a nose port and a pawl configured to push one or more of a fastener. The nose port can be configured between the feed piston and the pawl, and the feed piston pressure tube can connect the feed tube opening and the nose port. 
     In an embodiment, a compressed air distribution system for a pneumatic fastener can have a source of a compressed air which can be used to drive a driver of a fastener and also to move the feed piston away from a feed piston nose stop when a trigger is actuated to drive a fastener. 
     In an embodiment, a method for feed piston control, can have the steps of: providing a fastening device having an over-piston chamber, a pressure reservoir chamber and a plenum chamber; providing an reservoir bulkhead configured between the over-piston chamber and the pressure reservoir chamber; providing a plenum bulkhead configured between the pressure reservoir chamber and the plenum chamber; and providing a feed piston pressure tube which passes through each of the reservoir bulkhead and the plenum bulkhead to connect a feed tube opening and a feed piston return air inlet of the feed piston return chamber through which compressed air can be fed. The method can further have the steps of providing a feed tube opening feeding a compressed air from the pressure reservoir chamber; providing a feed piston and a feed pawl; providing a feed piston return chamber configured between the feed piston and the feed pawl; and selectively feeding the compressed air from the pressure reservoir chamber to the feed tube opening through the feed piston pressure tube and through the feed piston return air inlet into the feed piston return chamber. 
     In an embodiment, the method for feed piston control according can also have the steps of opening the head valve; flowing compressed air to the driver assembly and simultaneously flowing of the compressed air into the chamber created by the nose and feed piston; raising the pressure of the chamber created by the nose and feed piston; and driving the feed piston away from the drive channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present technology in its several aspects and embodiments solves the problems discussed above and significantly advances the technology of pneumatic fastening tools. The present technology can become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a pneumatic fastening tool showing the trigger mechanism; 
         FIG. 2  is a perspective view of the pneumatic fastening tool showing the compressed air connector; 
         FIG. 3  is a sectional view of the pneumatic fastening tool; 
         FIG. 4  is a detail sectional view showing the feed piston pressure tube; 
         FIG. 5A  shows a restriction valve assembly in the connecting tube flow path; 
         FIG. 5B  shows a restriction valve assembly in the connecting tube flow path in its actuated state; 
         FIG. 6  is a detail sectional view of the feed piston assembly in a resting state; 
         FIG. 7  is a detail sectional view of the feed piston assembly in an actuated state; 
         FIG. 8  is a sectional view showing the integrated valve assembly in a resting state in which no compressed air is fed to the feed piston assembly; and 
         FIG. 9  is a sectional view showing the integrated valve assembly in an actuated state in which compressed air is fed to the feed piston assembly via the feed piston pressure tube. 
     
    
    
     Herein, like reference numbers in one figure refer to like reference numbers in another figure. 
     DETAILED DESCRIPTION OF THE INVENTION 
     This disclosure relates to the many and varied embodiments of a pneumatic fastening tool technology which can be in non-limiting example a nailer, a stapler, a riveter or other device. The technology described herein can be used for a variety of pneumatic fastening tools and/or devices such as, but not limited to, nailers, roofing nailers, coil roofing nailer, finishing nailers, staplers, industrial staplers, or fine wire staplers. In an embodiment the pneumatic fastening tool  1  can drive fasteners such as, but not limited to, nails having a length in a range of from 0.25 inch to 2.0 inch or longer, such as 0.75 inch, 1 inch, 1.75 nails, or longer nails. 
       FIG. 1  illustrates a pneumatic fastening tool  1  according to one embodiment of the present invention. The pneumatic fastening tool  1  includes a housing  104  that is preferably constructed from a lightweight, yet durable material, such as magnesium, aluminum, or other suitable material. The drive mechanism for driving a fastener is received within the housing  104  of the pneumatic fastening tool  1 . The housing  104  can have one or more ports for a compressed air feed and one or more exhaust ports to purge exhaust air. 
     As illustrated, the pneumatic fastening tool  1  includes a handle  585  that can extend substantially perpendicularly from the housing  104 . The handle  585  is configured to be grasped by a user&#39;s hand, thereby making the pneumatic fastening tool  1  portable. A trigger valve assembly  200  having a trigger  252  is provided for actuating a drive assembly  198  within the housing  104 . The pneumatic fastening tool  1  can further have a nosepiece  131  connected to the housing  104 . A contact trip assembly can be provided to minimize the risk of injury to the user using the pneumatic fastening tool  1 . The handle  585  can have a handle top end  519  to which the housing  104  can be coupled. 
     The drive assembly  198  can have a driver cylinder  119  at least in part containing a drive piston  109 . The drive piston  109  can have a driver blade  199  which can engage the head of a fastener to be driven  556  using the energy provided by the drive assembly  198  within the housing  104 . In this regard, the nosepiece  131  receives consecutively fed fasteners from a feed canister  163 . 
       FIG. 3  is a sectional view of the pneumatic fastening tool  1  in accordance with an embodiment of the present invention. As can be seen, the nosepiece  131  can have a drive channel  352  into which a fastener to be driven  556  is fed from the feed canister  163 . The fastener to be driven  556  that is received in the drive channel  352  can be engaged by the driver blade  199  that engages the head of the fastener to be driven  556 , and drives the fastener to be driven  556  into a workpiece using the force provided by the drive assembly  198 . 
     The feed canister  163  can contain a coil of fasteners  558  which can be fed to the drive channel  352 . Optionally, a canister spine  62  can have a shingle guide  162  can be used facilitate an operator&#39;s ease of aligning the pneumatic fastener  1  to properly fasten a shingle to a surface. 
     The contact trip assembly can have a lower contact arm  126  that is connected to the nosepiece  131 , as shown in  FIG. 1 , and an upper contact arm  124  that is operatively connected to the lower contact arm  126 . As shown in  FIGS. 1 and 2 , the lower contact arm  126  can be integrated into the nosepiece  131 . The nosepiece  131  optionally can have a contact pad  810 , such as for example a no mar contact pad, and that is configured to be placed on a workpiece, at a distal end of the nosepiece  131 . 
     In an embodiment, movement of the lower contact arm  126  by contact with a workpiece can also move the upper contact arm  124  and position a contact pin  870  ( FIG. 9 ) in a triggering position in a actuated position such that when a trigger  252  is actuated the trigger can cause a fastener to be driven. In an embodiment, if the contact pin  870  is not in an actuated position, the pneumatic fastener  1  will be prevented from driving a fastener into a workpiece. 
       FIGS. 1 and 2  also show a depth adjust mechanism  127  which optionally can be adjusted by a thumb wheel  125 . The thumb wheel  125  can be adjust by an operator to drive a depth adjust cam that that can set a fastener drive depth. 
     As shown in  FIGS. 2 and 3 , the handle  585  can have a compressed air connector  300 . A compressed air supply (not shown) can be attached to the compressed air connector  300  to provide compressed air  444  to actuate operations of the pneumatic fastening tool  1 . The compressed air connector  300  can be a compressed air feed inlet to supply compressed air  444  to a pressure reservoir chamber  144 . In an embodiment, the handle  585  can also have an outlet port  595  for exhaust air. In an embodiment, the pressure reservoir chamber  144  of the handle  585  can feed compressed air  444  to the over-piston chamber  390 . Compressed air  444  can flow from the over-piston chamber  390  to the drive assembly  198  and/or the feed piston pressure tube  420 . 
       FIG. 3  also shows various chambers for controlling the compressed air  444 , the plenum air  333  which can flow through the plenum chamber  147  and exhaust air  555 , resulting for example from driving fasteners, and which can be exhausted from the pneumatic fastening tool the outlet port  595  of handle  585  and/or through housing exhaust chamber  610  and/or other exhaust passage or port. The actuation of the drive assembly  198  can be driven by the flow of compressed air  444 . In an embodiment, the drive assembly  198  can a driver piston  109  which can which can bear a driver blade  199 . 
     The flow of compressed air  444  can be controlled in a resting state by feeding the compressed air  444  to pressurize a pressure reservoir chamber  144 . As shown in  FIG. 3 , the pressure reservoir chamber  144  includes a portion of the handle  585  volume as well as the volume between the reservoir bulkhead  114  which can separate the pressure reservoir chamber  144  from the over-piston chamber  390 . The plenum bulkhead  120  can separate the pressure reservoir chamber  144  from the plenum chamber  147  and which can surround a portion of the driver cylinder  119 . 
     The “compressed air  444 ” in additional to its ordinary and customary meaning is defined herein as air having a pressure of 50 psig or greater which can actuate the drive assembly  198  and/or to actuate the head valve assembly  500  of the integrated valve assembly  600  and/or actuate the movement of feed piston  142 . In an embodiment, the compressed air  444  can have a pressure in a range of 50 psig to 300 psig, or 70 psig to 220 psig, or 70 psig to 180 psig. In an embodiment, the compressed air can have a pressure in a range of 70 psig to 120 psig. Compressed air  444  can drive the drive piston  109  and can also be fed through the pressure tube inlet  412  to the feed piston pressure tube  420  to actuate the movement of the feed piston  142  and/or pressurize the feed piston return chamber  450  ( FIG. 7 ). 
     “Plenum air  333 ” is the air controlled in the plenum chamber  147  and/or within the driver cylinder  119  between the driver piston  109  and the nose end of the driver cylinder  119 . “Plenum air  333 ”, is not within the definition of “compressed air  444 ” herein. 
     “Exhaust air  555 ” is air which is exhausted from the pneumatic fastening tool, such as “exhaust air  555 ” which can exit through the outlet port  595  of handle  585  and/or through housing exhaust chamber  610  ( FIG. 8 ) and/or other exhaust passage or port. “Exhaust air  555 ” is not within the definition of “compressed air  444 ” herein. 
       FIG. 3  is a sectional view of the pneumatic fastening tool  1 . In an embodiment, the pressure reservoir chamber  144  can contain compressed air  444 . In an embodiment, the over-piston chamber  390  can be configured between the cap  103  and the driver  109  which, when actuated, drives the driver blade  199 . The driver blade  199  can be coaxial disposed within the drive cylinder  119  to drive a fastener fed to the drive channel  352  into a workpiece. The over-piston chamber  390  can be a pressure chamber configured as a source to provide a compressed air from a reservoir to one or more features of the pneumatic fastening tool, such as the driver  109  and/or the feed piston return chamber  450  ( FIGS. 6 and 7 ), or other feature. When the pneumatic fastening tool  1  is actuated to drive a fastener, the compressed air  444  can flow through the compressed air inlet port  710  to the over-piston chamber  390  which as shown in  FIG. 9  can drive the driver  109  and feed compressed air  444  to a feed piston pressure tube  420 . 
     In an embodiment, the pressure reservoir chamber  144  can have a portion which contains compressed air  444  in the handle  585 . When the pneumatic fastening tool  1  is in the actuated state, compressed air  444  can be fed from the pressure reservoir chamber  144 , to the over-piston chamber  390  and the feed piston return chamber  450 . 
       FIG. 3  shows the pressure reservoir chamber  144 , over-piston chamber  390  and plenum chamber  147  in a resting and/or exhausting state. When the drive piston  109  is actuated, the plenum chamber  147  receives the air the drive piston  109  pushes out from the driver cylinder  119 . In an embodiment, the resting state for the pressure reservoir chamber  144 , over-piston chamber  390  and plenum chamber  147  is achieved when the air within these chambers is exhausted over an exhaust time period. In an embodiment, when the head valve assembly  500 , which is used to control the flow of compressed air  444  to at least the drive assembly  198  and feed piston pressure tube  420 , achieves its resting state sealed with the handle reservoir surface  711  ( FIG. 8 ) of handle  585 , exhaust air  555  can exit through an integrated valve assembly  600 . The integrated valve assembly  600  can have a cylindrical shape and control driving and exhaust air flows. In an embodiment, the use of feed piston pressure tube  420  to control the position of the feed piston  142  when driving a fastener and the integrated valve assembly  600  can achieve a number of design and operation advantages such as, but not limited to a high drive cycle speeds, a weight of 5.5 lbs or less with ergonomic balance in the hand of an operator during use and low recoil characteristics resulting from component location, weight distribution, as well as the configuration moving masses. 
     In an embodiment, the compressed air  444  can have a pressure in a range of 50 psig to 500 psig, or 70 psig to 220 psig, or 70 psig to 180 psig. In an embodiment, the compressed air can have a pressure in a range of 80 psig to 120 psig. Compressed air  444  can drive the drive piston  109  and can also be fed to the feed piston pressure tube  420  to actuate the movement of the feed piston  142  and/or pressurize the feed piston return chamber  450  which houses the feed piston  142 . 
     A compressed air supply (not shown) can be attached to the compressed air connector  300  to provide a compressed air  444  to handle reservoir chamber  587 . In an embodiment, the handle  585  can also have an outlet port for exhaust air. In an embodiment, the handle reservoir chamber  587  of the handle  585  can feed compressed air  444  to the over-piston chamber  390  chamber and the integrated valve assembly  600 . 
       FIG. 3  also shows the feed piston pressure tube  420  which passes through a reservoir bulkhead  114  and a plenum bulkhead  120 .  FIG. 3  also shows a feed piston assembly  190  that that can drive and/or control the feeding of a fastener into a drive channel  352 . In an embodiment, the feed piston assembly  190  includes the feed piston  142 , a feed piston nose stop  143  and a feed spring  140  which is biased to impart a force upon the feed piston toward the feed piston nose stop  143 . 
     The trigger  252  can be actuated to trigger the drive piston  109  to drive a fastener. Upon actuation of the trigger  252 , pneumatic pressure can cause the drive piston  109  to drive the driver blade  199  to drive a fastener into a workpiece. The housing  104  can have a portion which forms a cap  103  that covers the over-piston chamber  390 . 
     In an embodiment, the trigger  252  can optionally be configured such that both a contact pin  870  and a trigger pin  850  have to be in an actuated configuration in order to trigger the trigger valve assembly  200 . The contact pin  870  and the trigger pin  850  can together, or optionally separately, can trigger and/or actuate the trigger valve assembly  200  of the integrated valve assembly  600 . Optionally, a trigger actuator  860  can be used to contact the trigger valve assembly  200  to actuate the trigger valve assembly  200  of the integrated valve assembly  600 . As shown in  FIG. 3 , the trigger actuator  860  requires that the trigger pin  850  and the trigger  252  both be in an actuating position for the trigger actuator  860  to compress the trigger spring  251  and move a proximal trigger stem  215  to actuate the trigger valve assembly  200 . 
     In the embodiment shown in  FIGS. 1-3 , in order for the trigger valve assembly  200  to be actuated, the trigger pin  850 , the contact pin  870  and the trigger  252  must be in an actuated configuration at the same time. Optionally, the position of the contact pin  870  can at least in part be determined by the position of the upper contact arm  124 . Specifically, the movement of the lower contact arm  126  resulting from contact with a workpiece can move the upper contact arm  124  to position a contact pin  870  in a triggering position. The contact pad  810  can directly, or by an intermediate linkage, move the upper contact arm  124  which can move trigger pin  850  to a configuration to allow for triggering of the trigger valve assembly  200  upon a simultaneous actuation of the trigger  252  by an operator. In the example of  FIG. 3 , the trigger actuator  860  requires that the trigger pin  850  and the trigger  252  both be in an actuating position for the trigger actuator  860  to compress the trigger spring  251  and move the proximal trigger stem  215  to actuate the trigger valve assembly  200 . 
     In an embodiment, a feed tube assembly  400  can feed compressed air  444  to the feed piston pressure tube  420  and/or the feed piston return chamber  450 .  FIG. 4  is a detail sectional view showing a feed tube assembly  400  which can have the feed piston pressure tube  420  extending from a feed tube nozzle  405  through a feed tube opening  410  to a nose channel inlet  440  which feeds the feed piston return chamber  450  through a nose port  445 . 
       FIG. 4  shows the feed piston pressure tube  420  which provides a passageway for flow of the compressed air  444  from a compressed air source to the feed piston  142  thereby forcing the feed piston  142  to momentarily move in a direction away from the drive channel  352 . The temporary movement of the feed piston  142  facilitates a successful driving of a fastener  556  to be driven and a successful feed of a next fastener  557  to be driven upon the following movement of the feed piston  142  back toward the drive channel  352 . In an embodiment, the fasteners  556 ,  557  can be fed from a fastener coil  558  or a stick of fasteners. 
       FIG. 4  also shows the flow of compressed air  444  entering pressure tube inlet  412  flowing through the feed piston pressure tube  420  to pass through a feed tube outlet  430  to then flow through the nose channel  440  into the feed piston return chamber  450 . In an embodiment, the flow of compressed air  444  through the feed piston pressure tube  420  can exit directly into the feed piston return chamber  450 . The compressed air  444  can be fed to the feed piston pressure tube  420  from the handle reservoir chamber  587  and/or the over-piston chamber  390  and/or pressure reservoir chamber  144 , or other source. 
     In an embodiment, the feed piston pressure tube  420  can have an inner diameter  429  in a range of 1 mm to 20 mm, or greater, such as 3 mm, 5 mm or 10 mm. In an embodiment, the feed piston pressure tube  420  can have a length of from 25 mm to 250 mm, such as 115 mm. Optionally, the feed piston pressure tube  420  can comprise multiple tubes forming a passageway for compressed air  444  each of which has a length in a range of 2 mm to 250 mm. 
     In the embodiment of  FIG. 4 , the feed piston pressure tube  420  is configured to pass through a reservoir bulkhead opening  108  in the reservoir bulkhead  114  and through a plenum bulkhead opening  107  in the plenum bulkhead  120 .  FIG. 4  shows the feed piston pressure tube  420  passing through a reservoir bulkhead  114  of pressure reservoir chamber  144  and a plenum bulkhead  120  of plenum chamber  147  to reach the nose channel  440  feeding the feed piston return chamber  450 . Optionally, the reservoir bulkhead  114  and/or the plenum bulkhead  120  can have nozzles and passages to which segments of the feed piston tube can connect thus forming a multi-segmented channel though which compressed air  444  can flow from a source to the feed piston  142  and/or the feed piston return chamber  450  and/or the nose channel  440 . 
     In its several and varied embodiments, compressed air  444  can be fed to provide a force upon the feed piston  142  to move the feed piston  142  away from the drive channel  352  when the trigger valve assembly  200  of the integrated valve assembly  600  is actuated by an operator and/or when the head valve assembly  500  is actuated by an operator. 
     When the trigger valve assembly  200  and the head valve assembly  500  achieve an active state ( FIG. 9 ), the compressed air  444  can be fed to the drive assembly  198  and the driver blade  199  can drive a fastener to be driven  556  ( FIG. 8 ) through the drive channel  352  into a workpiece. Then, the feed piston pressure tube  420  can provide the compressed air  444  to retract a feed piston  142  and feed pawl  141 . 
     While the example of  FIG. 4  shows a feed piston pressure tube  420 , this disclosure is not limited in the types of members by which compressed air  444  can be provided to retract the feed piston  142  and the feed pawl  141 . In a non-limiting example, one or more of the following can be used to provide compressed air  444  to the feed piston  142  and/or the feed piston return chamber  450 : a passageway, a channel, a pipe, a tubular member, a feed piston pressure tube  420 , a valve, or an opening. 
     In an embodiment, creating a momentary delay between the time that the compressed air  444  first begins to move the drive piston  109  and the moment that compressed air  444  begins to retract the feed piston  142  and the feed pawl  141 , can provide a benefit in coordinating the striking of the fastener to be driven  556  by the driver blade  199  and the movement of the feed pawl  141  away from the driver being struck. Thus, the driver blade  199  can strike a fastener to be driven  556  which is free of contact from the feed pawl  141  at the moment of being driven. This momentary delay can be achieved by placing a member that causes such delay in the flowpath of the compressed air  444  to the feed piston  142  and/or feed piston return chamber  450 , such as an orifice, flow restriction member, pressure let-down member, valve, or other member or configuration for achieving such a momentary delay in the initial flow of compressed air  444  to the feed piston  142  and/or feed piston return chamber  450 . 
     In the example of  FIG. 4 , an orifice bead  405 , which is a type of orifice member, is used to create a momentary delay between the time that the compressed air  444  first begins to move the piston  109  and the moment that compressed air  444  begins to retract the feed piston  142  and the feed pawl  141 .  FIG. 4  shows the orifice bead  405  housed at least in part in an orifice chamber  399 . The orifice bead  405  can receive compressed air  444  through an air feed gap  411  and provide a pressure drop to the compressed air  444  fed to the feed tube opening  410 . 
       FIG. 4  also shows a feed piston assembly  190  which is fed compressed air through the nose port  445  to the feed piston return chamber  450 . The force of the compressed air against the feed piston  142  can overcome the bias of feed piston spring  344  toward the feed piston nose stop  143  to move the feed piston  142  away from the feed piston nose stop  143 . 
     In an embodiment, the feed pawl  141  can have a feed pawl shaft  189  ( FIGS. 6 and 7 ) and a feed pawl head  741 . When the feed piston  142  is in a resting state, the feed pawl  141  is biased to contact one or more of the fasteners and to push the one or more fasteners toward the drive channel  352 . The feed pawl  141  can be configured to move in concert with the movement of the feed piston  142 . 
       FIG. 5A  is a detail view of the orifice chamber  399 . In the embodiment shown, the combination of the orifice chamber  399  and orifice bead  405  achieve restriction to the flow of compressed air  444 , which is referred to herein as a flow restriction assembly  413 . In a non-limiting example a flow restriction assembly  413  can be an orifice valve, a restriction plate, a let-down valve, a valve, a porous member, or other member. 
       FIG. 5A  shows a pressure drop member which can be a flow restriction assembly  413 . The flow restriction assembly  413  can receive the flow of compressed air  444  during a resting state or at the end of an exhaust cycle. The flow restriction assembly  413  can be in the feed piston pressure tube flow path  421  of the feed piston pressure tube  420 .  FIG. 5A  shows the flow restriction assembly  413  in at the moment compressed air  444  flow of compressed air  444  flows to an orifice chamber inlet  398  to a flow restriction assembly  413 . 
     The orifice bead  405  can have an orifice inlet  407  and an orifice outlet  409 . The orifice bead  405  can be housed in an orifice chamber  399 . Optionally, a bead stop  401  can be used to limit the movement of the orifice bead  405  and maintain the orifice bead  405  in the orifice chamber  399 . In an embodiment, the movement of the orifice bead can be limited between the bead stop  401  and the orifice chamber outlet  403 . 
     In the resting state or during the exhaust cycle, optionally as shown in  FIG. 5A , the orifice bead  405  can be separated from the pressure tube inlet  412  which can provide a rest gap  415 . 
       FIG. 5A  shows the moment the compressed air  444  contacts the orifice bead  405 . The contact of the compressed air  444  can exert pressure upon the orifice bead  405  which can move the orifice bead  405  toward the orifice chamber outlet  403 . In a state in which the pneumatic fastening tool  1  is fully exhausted the orifice bead  405  can move within the orifice chamber  399  freely in accordance with gravitational forces on the orifice bead  405 . 
     Once the orifice bead  405  reaches the orifice chamber outlet  403  and compressed air  444  flows through an orifice channel  402  and into a feed piston pressure tube flow path  421 , the flow restriction assembly  413  has reached its actuated state. 
     In an embodiment, the compressed air  444  entering the orifice chamber inlet  398  can flow through an orifice channel  402  and into a feed piston pressure tube flow path  421 , as well also flow around the orifice bead  405  and directly enter the feed piston pressure tube flow path  421 . 
       FIG. 5B  shows a flow restriction assembly  413  in an actuated state. In the actuated state, the orifice bead  405  can be configured adjacent to the orifice chamber outlet  403 . In the actuated state, the flow of compressed air  444  can flow through the air feed gap  411  and into an orifice inlet  407  thought the orifice channel  402  out of the orifice outlet  409  out of the orifice chamber outlet  403  and into the feed piston pressure tube flow path  421  of feed piston pressure tube  420 . 
     The pressure drop member, such as the orifice bead  405 , can achieve a pressure drop in the compressed air flow across the pressure drop member. The pressure drop can cause a slight delay between when the compressed air  444  first causes the movement of the drive piston  109  to drive a fastener and when the compressed air  444  later causes the movement of the feed piston  142  away from a feed piston housing pawl end  195 . The striking a the fastener to be driven  556  by the driver blade  199  can be coordinated with the retraction of the feed piston  142  away from a feed piston housing pawl end  195 . Timing the movement of the feed piston  142  away from a feed piston housing pawl end  195  to occur slightly after the drive piston  109  is actuated can synchronize the striking of the fastener to be driven  556  by the driver blade  199  and the movement of the feed piston  142  and feed pawl  141  away from the fastener to be driven  556  so as to reduce and/or eliminate the likelihood of a misfire. In an embodiment, the timing of actuation of the movement of the feed piston  142  can be set by use of a flow restriction assembly  413  and/or orifice member, such as orifice bead  405 , to maximize the period in which the feed pawl  141  contacts a fastener, but still withdraws the feed pawl  141  in sufficient time not to interfere with the contact of the driver blade  199  by the drive piston  109  to a fastener to be driven  556 . 
     The  FIG. 5B  example uses an orifice bead  405  to achieve a pressure drop, APorifice, between the orifice bead inlet  407  and orifice bead outlet  409 . The compressed air  444  exiting the orifice bead outlet  409  has a pressure which is less than the pressure of compressed air source minus APorifice, or less. In the case of the embodiment of  FIG. 5B , the orifice bead outlet  409  pressure can be the pressure of the reservoir chamber  144  and/or the handle minus APorifice, or less. 
     In an embodiment, exhaust air from the feed piston return chamber  450  can flow through an orifice channel  402  and into a feed piston pressure tube flow path  421 , as well also flow around the orifice bead  405 . Lower pressure exhaust air from the feed piston return chamber  450  can at least in part bypass flowing through the orifice bead  405 . 
       FIG. 6  shows a detail sectional view of the feed piston assembly  190  in a resting state. The feed piston assembly  190  can have a feed piston housing  193 , a feed piston  142 , a feed piston spring  140 , a feed piston housing base end  194  and a feed piston housing pawl end  195 . The feed piston spring  140  biases the feed piston  142  toward the feed piston housing pawl end  195 . The feed piston  142  can be sealed against the feed piston housing  193  by a feed piston seal  196  and the feed pawl shaft  189  can be sealed against the feed piston housing  193  by piston housing seal  197 . 
       FIG. 6  shows the feed piston return chamber  450 . The feed piston return volume  451  of the feed piston return chamber  450  is dependent upon the position of the feed piston  142 . The feed piston return volume  451  can range from zero if the feed piston pawl face  188  is flush against the feed piston housing pawl end  195  and the compressed air inlet port is through the feed piston housing pawl end  195 , to an actuated volume between the feed piston pawl face  188  and the feed piston housing pawl end  195  when the feed piston  142  is in its actuated state ( FIG. 7 ). 
       FIG. 6  shows the feed piston  142  in a resting state in which the feed piston pawl face  188  is a minimum distance from the feed piston housing pawl end  195 . A flow of compressed air  444  is shown to the feed piston return chamber  450  to begin actuating movement of the feed piston  142  away from the feed piston housing pawl end  195 . At the moment shown in  FIG. 6 , The flow of compressed air  444  is shown through feed piston pressure tube  420  into the nose channel inlet  440  out of a nose port  445  and into the feed piston return chamber  450  exerting a feed piston return force  452  against the feed piston  142  and counter to the feed piston spring bias  451 . 
     When the feed piston return force  452  exceeds the feed piston spring bias  451  and other frictional forces, such as the frictional force created by feed piston seal  196 , then the feed piston  142  starts to move away from the feed piston housing pawl end  195 . 
       FIG. 7  is a detailed sectional view of the feed piston assembly  190  in an actuated position in which the feed piston  142  is at a maximum distance from the feed piston housing pawl end  195 . At the moment shown in  FIG. 7 , the feed piston return chamber  450  has the feed piston return volume  451  which is at a maximum volume. In the fully actuated state shown in  FIG. 7 , the feed pawl has been moved by the feed piston  142  to its maximum distance from the drive channel  352  of the feed piston assembly  190 . 
     When the flow of compressed air  444  ceases, then the feed piston spring bias  451  can overcome the feed piston return force  452 , which is diminishing, and other forces, as the air pressure within the feed piston return chamber  450  decreases. When the feed piston spring bias  451  overcomes the piston return force  452  and other forces, then the spring will push the feed piston  142  toward the feed piston housing pawl end  195 , thus returning the feed piston  142  to the resting position of feed piston  142  and returning the feed piston assembly  190  to a resting state. 
       FIG. 8  is a sectional view showing the integrated valve assembly  600  in a resting state blocking the flow of compressed air  444 . In an embodiment, the head valve assembly  500  can use a seal member to form a seal between the head valve body  510  and a portion of the pressure reservoir chamber  144  so as to stop the flow of the compressed gas  444  into the compressed air inlet port  710 .  FIG. 8  shows the head valve seal member  517  creating a seal with the handle reservoir surface  711  and blocking the compressed air inlet port  710  from receiving the flow of compressed air  444 . In an embodiment, the head valve housing  510  can have a head valve seal member  517 , which can optionally be an O-ring. In an embodiment, the head valve seal member  517  can press against the handle reservoir surface  711  forming a seal which achieves the resting state of the head valve assembly  500  and in conjunction with the head valve body  510  blocks the flow of compressed air  444  from reaching the compressed air inlet port  710  when the head valve assembly  600  is in the resting state. As shown in  FIG. 8  at a resting state the head valve  515  can be at a distance from exhaust seal  520 . In an embodiment, the exhaust seal  520  can be made of a plastic or polymer, such as urethane to engage sealingly with the head valve body  510  and/or head valve  515 . The head valve body  510  and/or head valve  515  can be made from a plastic, metal, composition, or other material, such as plastic or brass. 
       FIG. 8  also shows the flow of compressed air  444  into the head valve line  590  and pressurizing the annulus chamber  597  to achieve and/or maintain the head valve assembly  500  in the resting state. In the head valve assembly  500  resting state, the drive assembly  198  and the feed piston assembly  190  are also in a resting state. In the resting state, the drive cylinder  119 , a snorkel air passage  700 , plenum chamber  147 , over-piston chamber  390 , feed piston return chamber  450  and housing exhaust chamber  610  are each depressurizing and/or unpressurized to, or close to, ambient pressure, or about 0 psig, and are free of the compressed air  444 . 
     In an embodiment, snorkel air passage  700  can be a conduit having a portion which can be curved. The curved portion of the snorkel air passage  700  can optionally and in nonlimiting example have a curved shape analogous to a portion of a snorkel. 
     In this configuration, compressed air  444  from the handle reservoir chamber  587 , or other source, such as the pressure reservoir chamber  144 , can be fed through the reservoir line  580  to pass through a head valve line  580  to pressurize the annulus chamber  597  and move and maintain the head valve assembly  500  in its resting state. 
     In the resting state, the proximal trigger stem  215  is biased by trigger spring  251  to press against and close the stem exhaust port  270  of trigger valve assembly  200 . 
     In the resting state, the head valve housing  510  is configure to seal a compressed air inlet port  710  preventing a flow of compressed air  444  through the snorkel passage  700  to the over-piston chamber  390 . 
       FIG. 9  is a sectional view showing the integrated valve assembly  600  in an actuated state. In the actuated state, the annulus chamber  597  is purged of air and resulting pressure differential across the head valve  515  and head valve body  510  and the pressure from the compressed air  444  causes the head valve assembly  500  to reach an actuated state. When the head valve assembly  500  is in the actuated state, the flow of compressed air  444  to each of the snorkel air passage  700 , the over-piston chamber  390 , drive assembly and drive cylinder  119  and the feed piston return chamber  450 . In an actuated state, if both the contact pin  870  and trigger pin  850  are each in an actuated configuration, the trigger actuator  860  can actuate the integrated valve assembly  600  and trigger the driving of a fastener into a workpiece. 
     In an actuated state, the head valve  515  is pressed against the exhaust seal  520  which obstructs the flow of compressed air through exhaust openings  521  and achieves the actuated state of the head valve assembly  500 . 
     In an embodiment, a drive cycle speed of a pneumatic fastening tool which can be a function of the trigger and head valve operation, piston return and feed system characteristics, compressed air supply and exhaustion. 
     The feed piston pressure tube  420  alone, or in combination with the integrated valve assembly  600 , supports the high drive cycle speed which achieves a drive frequency, of drives of the driver assembly  198 , of 0 to 25 drives per second, which can also can be characterized as 0 to 25 fasteners driven per second. In an embodiment the pneumatic fastening tool can achieve a drive cycle speed of 14 to 25 drives per second, or of 14 to 25 drives fasteners driven per second. In another embodiment the pneumatic fastening tool can achieve a drive cycle speed of 5 to 15 drives per second, or fasteners of 5 to 15 driven per second. In another embodiment the pneumatic fastening tool can achieve a drive cycle speed of 6 to 12 drives per second, or of 6 to 12 fasteners driven per second. The use of the feed piston pressure tube  420  alone, or in combination with the integrated valve assembly  600 , achieves a rapid drive cycle speed at which the nailer can be fired without a firing pause or delay caused by factors associated with the tool returning to a rest or pre-actuated state, such as exhausting air or mechanical transition from actuated to a resting and/or pre-firing state. 
     Each the feed piston pressure tube  420  and the integrated valve assembly  600  use separately achieved increased drive cycle speed of a pneumatic fastening tool  1 . The use of the feed piston pressure tube  420  increased the drive cycle speed which can be achieved by reducing and/or freeing the fastener to be driven  556  from the physical forces of the feed pawl  141  when the feed piston assembly  190  is in a actuated state and the feed pawl  141  is not in contact with a fastener. In an embodiment, the use of the feed piston pressure tube  420  to actuate the feed piston assembly  190  when the compressed gas pressure is in a range of 70 psig to 150 psig, or 70 to 120 psig achieves high drive cycle speeds with reduced misfire events. The feed piston pressure tube  420  achieve a particular advantage in increased drive cycle speeds at less than 100 psig, or less than 80 psig, or even less than 70 psig. Thus, when the pneumatic fastening tool  1  is being fired at a fast rate and the compressed air  444  pressure in the pressure reservoir chamber is declining as a result of use, the pneumatic fastening tool  1  using feed piston pressure tube  420  can nonetheless achieve high drive cycle speeds. In an embodiment, use of the feed piston pressure tube  420  can achieve drive cycle speeds of 0 to 15, or 6 to 18, such as 12, 14 or 15, drives per second, or fasteners driven per second 
     In another aspect, the integrated valve assembly  600  achieves a fast and efficient valve motion. The integrated valve assembly  600  can alone achieve high drive cycle speeds. When the integrated valve assembly  600  is used in conjunction with the feed piston pressure tube  420  which can actuate the feed piston assembly  190  and very high drive cycle speeds are achieved, such as in a range of from 6 to 20 drives per second, or fasteners driven per second. 
     In an embodiment, the drive cycle speed of a pneumatic fastening tool  1  using compressed air  444  of 100 psig and a feed piston pressure tube  420  can achieve a drive cycle speed of 0 to 15, such as 12, 14 or 15, drives per second, or fasteners driven per second. In an embodiment, the pneumatic fastening tool  1  can have an integrated valve assembly  600 , a compressed air  444  having a pressure of 70 psig or greater, a drive cycle speed of 10 drives per second and a weight of 6 lbs or less, such as 5.5 lbs or less, or 5 lbs or less. In another example, the pneumatic fastening tool  1  having fasteners fed from a fasteners coil  558  can achieve the drive cycle speed of greater than 5 drives per second, or fasteners driven per second. In yet another example, the pneumatic fastening tool  1  having fasteners fed from a fasteners coil  558  can achieve the drive cycle speed in a range of 6 to 15, drives per second, or fasteners driven per second such as 12, 14 or 15 drives per second, or fasteners driven per second. 
     Numeric values and ranges herein, unless otherwise stated, also are intended to have associated with them a tolerance and to account for variances of design and manufacturing. Thus, a number can include values “about” that number. For example, a value X is also intended to be understood as “about X”. Likewise, a range of Y-Z, is also intended to be understood as within a range of from “about Y-about Z”. Unless otherwise stated, significant digits disclosed for a number are not intended to make the number an exact limiting value. Variance and tolerance is inherent in mechanical design and the numbers disclosed herein are intended to be construed to allow for such factors (in non-limiting e.g., ±10 percent of a given value). Likewise, the claims are to be broadly construed in their recitations of numbers and ranges. 
     Additionally herein geometric references are intended also to be construed to account for variance, for example the term “circular” is intended to encompass “substantially circular”, “generally circular”, or other reasonable variations in the context of the embodiments disclosed herein. Likewise the term “cylindrical” is intended to encompass “substantially cylindrical”, “generally cylindrical”, or other reasonable variations in the context of the embodiments disclosed herein. 
     This disclosure regards a pneumatic fastening tool and its many aspects, features and elements. Such an apparatus can be dynamic in its use and operation. This disclosure is intended to encompass the equivalents, means, systems and methods of the use of the pneumatic fastening tool and its many aspects consistent with the description and spirit of the apparatus, means, methods, functions and operations disclosed herein. Other embodiments and modifications will be recognized by one of ordinary skill in the art as being enabled by and within the scope of this disclosure. 
     The scope of this disclosure is to be broadly construed. The embodiments herein can be used together, separately, mixed or combined. It is intended that this disclosure disclose equivalents, means, systems and methods to achieve the devices, designs, operations, control systems, controls, activities, mechanical actions, dynamics and results disclosed herein. For each mechanical element or mechanism disclosed, it is intended that this disclosure also encompasses within the scope of its disclosure and teaches equivalents, means, systems and methods for practicing the many aspects, mechanisms and devices disclosed herein. The claims of this application are likewise to be broadly construed. 
     The description of the technology herein in its many and varied embodiments is merely exemplary in nature and, thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the claims and the disclosure herein. Such variations are not to be regarded as a departure from the spirit and scope of the disclosed technologies. 
     It will be appreciated that various modifications and changes can be made to the above described embodiments of the power tool as disclosed herein without departing from the spirit and the scope of the claims.