Patent Publication Number: US-2023150101-A1

Title: Powered fastener driver

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/835,243, filed Apr. 17, 2019, the entire contents of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to power tools, and more particularly to powered fastener drivers adapted to drive fasteners into a workpiece. 
     BACKGROUND OF THE INVENTION 
     There are various fastener drivers known in the art for driving fasteners (e.g., nails, tacks, staples, etc.) into a workpiece. These fastener drivers operate utilizing various means known in the art (e.g. compressed air generated by an air compressor, electrical energy, a flywheel mechanism, etc.), but often these designs are met with power, size, and cost constraints. 
     SUMMARY OF THE INVENTION 
     The present invention provides, in one aspect, a gas spring-powered fastener driver. The fastener driver includes a first chamber, and a movable piston positioned within the first chamber. The fastener driver also includes a driver blade attached to the piston and movable therewith between a ready position and a driven position. The fastener driver further includes a second chamber containing pressurized gas. The second chamber is in fluid communication with the first chamber via a flow passage. The fastener driver also includes a throttle mechanism configured to throttle flow of the pressurized gas through the flow passage. 
     The present invention provides, in another aspect, a gas spring-powered fastener driver. The fastener driver includes a first cylinder defining a first chamber, and a movable piston positioned within the first chamber. The fastener driver also includes a driver blade attached to the piston and movable therewith between a ready position and a driven position. The fastener driver further includes a second cylinder surrounding the first cylinder, and a second chamber defined between the first cylinder and the second cylinder and containing pressurized gas. The second chamber is in fluid communication with the first chamber via a flow passage. The fastener driver also includes a throttle mechanism configured to throttle flow of pressurized gas through the flow passage. The throttle mechanism includes a baffle configured to selectively adjust an area of the flow passage. 
     Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a gas spring-powered fastener driver in accordance with an embodiment of the invention. 
         FIG.  2    is a partial cut-away view of the fastener driver of  FIG.  1   . 
         FIG.  3    is a cross-sectional view of the fastener driver of  FIG.  1    taken along line  3 - 3  of  FIG.  2   , illustrating a driver blade in a ready position. 
         FIG.  4    is a cross-sectional view of the fastener driver of  FIG.  1    taken along line  3 - 3  of  FIG.  2   , illustrating the driver blade in a driven position. 
         FIG.  5    is a partial cut-away view of the fastener driver of  FIG.  1   . 
         FIG.  6    is a cross-sectional view of the fastener driver of  FIG.  1    taken along line  6 - 6  of  FIG.  1   , illustrating a motor, a transmission, and a fan assembly. 
         FIG.  7    is a perspective view of a throttle mechanism of the fastener driver of  FIG.  1   . 
         FIG.  8    is another perspective view of the throttle mechanism of  FIG.  7    with portions removed. 
         FIG.  9 A  is a partial perspective view of the throttle mechanism of  FIG.  7    adjusted to a no-choke position. 
         FIG.  9 B  is a partial perspective view of the throttle mechanism of  FIG.  7    adjusted to a partial-choke position. 
         FIG.  9 C  is a partial perspective view of the throttle mechanism of  FIG.  7    adjusted to a choked position. 
         FIG.  10 A  is a cross-sectional view of the throttle mechanism of  FIG.  9 A . 
         FIG.  10 B  is a cross-sectional view of the throttle mechanism of  FIG.  9 B . 
         FIG.  10 C  is a cross-sectional view of the throttle mechanism of  FIG.  9 C . 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
       FIGS.  1 - 6    illustrate a power tool, such as a gas spring-powered fastener driver  10 , operable to drive fasteners (e.g., nails, tacks, staples, etc.) held within a magazine  12  into a workpiece. In the illustrated embodiment, the fastener driver  10  is configured as a multi-shot powered nailer including the magazine  12  holding a collated strip of fasteners, allowing the user to perform multiple fastening operations without having to manually reload the fastener driver  10  after each driving cycle. The gas spring-powered fastener driver  10  includes a gas spring assembly  14  for generating a motive force to drive each fastener into the workpiece. The gas spring assembly  14  includes a throttle mechanism  16  ( FIGS.  7 - 10 C ) for varying the power output of the fastener driver  10  when performing a fastener driving operation, as will be described in further detail below. 
     With reference to  FIGS.  3  and  4   , the gas spring assembly  14  includes an inner cylinder  18  and a moveable piston  22  positioned for reciprocating movement within an inner chamber  26  bounded by the inner cylinder  18 . The fastener driver  10  further includes a driver blade  30  that is attached to the piston  22  and moveable therewith. The fastener driver  10  does not require an external source of air pressure, but rather includes a storage chamber  34  filled with pressurized gas and positioned in fluid communication with the inner chamber  26 . The gas spring assembly  14  also includes an outer cylinder  38  positioned about the inner cylinder  18 . The storage chamber  34  is defined between the inner cylinder  18  and the outer cylinder  38 . In the illustrated embodiment, the inner cylinder  18  and moveable piston  22  are positioned within the outer cylinder  38 . 
     With reference to  FIG.  5   , the driver  10  further includes a fill valve  42  coupled to the outer cylinder  38 . When connected with a source of compressed gas, the fill valve  42  permits the storage chamber  34  to be refilled with compressed gas if any prior leakage has occurred. The fill valve  42  may be configured as a Schrader valve, for example. 
     The inner cylinder  18  and the driver blade  30  define a driving axis  46 , and during a driving cycle the driver blade  30  and piston  22  are moveable between a ready position (i.e., top dead center; see  FIG.  3   ) and a driven position (i.e., bottom dead center; see  FIG.  4   ). The fastener driver  10  further includes a lifting assembly  50 , which is powered by a motor  54  ( FIG.  6   ), and which is operable to move the driver blade  30  from the driven position to the ready position. 
     In operation, the lifting assembly  50  drives the piston  22  and the driver blade  30  to the ready position by energizing the motor  54 . As the piston  22  and the driver blade  30  are driven to the ready position, the gas above the piston  22  and the gas within the storage chamber  34  is compressed. Once in the ready position, the piston  22  and the driver blade  30  are held in position until being released by user activation of a trigger  58  ( FIG.  1   ). When released, the compressed gas above the piston  22  and within the storage chamber  34  drives the piston  22  and the driver blade  30  to the driven position, thereby driving the fastener into a workpiece. The illustrated fastener driver  10  therefore operates on a gas spring principle utilizing the lifting assembly  50  and the piston  22  to compress the gas within the inner chamber  26  and the storage chamber  34 . Further detail regarding the structure and operation of the fastener driver  10  is provided below. 
     With reference to  FIGS.  4  and  5   , the fastener driver  10  includes a housing  62  having a cylinder support portion  66  ( FIG.  3   ) in which the outer cylinder  38  is at least partially positioned, and a transmission housing portion  70  in which a transmission  74  ( FIG.  6   ) is at least partially positioned. The transmission  74  is a component of the lifting assembly  50 , which raises the driver blade  30  from the driven position to the ready position. The motor  54  is also a component of the lifting assembly  50  and is coupled to the transmission housing portion  70  for providing torque to the transmission  74  when activated. A battery pack  78  ( FIG.  1   ) is electrically connectable to the motor  54  for supplying electrical power to the motor  54 . In alternative embodiments, the driver may be powered from an AC voltage input (i.e., from a wall outlet), or by an alternative DC voltage input (e.g., a DC power support). 
     With reference to  FIG.  6   , the transmission  74  receives torque from the motor  54  via a motor output shaft  82 , and includes a transmission output shaft  86  to which a lifter  90  of the lifting assembly  50  is rotationally affixed ( FIGS.  5  and  6   ). The transmission  74  provides torque to the lifter  90 , causing the lifter  90  to rotate about an axis  92  ( FIG.  6   ) and return the driver blade  30  from the driven position to the ready position. A fan  94  is rotatably coupled to the motor shaft  82  to generate cooling airflow within an interior of the fastener driver  10 . 
     With reference to  FIGS.  7 - 10 C , the gas spring assembly  14  will now be described in further detail. The inner cylinder  18  includes an open end  98  that fluidly communicates with the storage chamber  34 . An end portion  102  of the outer cylinder  38  is located adjacent the open end  98  and substantially surrounds the open end  98 . A flow passage  106  is defined between the open end  98  and the end portion  102 , and fluidly connects the inner chamber  26  with the storage chamber  34 . The pressurized gas flows between the inner chamber  26  and the storage chamber  34  via the flow passage  106 . 
     The gas spring assembly  14  further includes the throttle mechanism  16  that selectively increases or reduces an area of the flow passage  106  to throttle the flow of pressurized gas between the inner chamber  26  and the storage chamber  34 . The throttle mechanism  16  includes a sliding sleeve or baffle  110  that surrounds the inner cylinder  18  adjacent the open end  98 . The baffle  110  is slidable in an axial direction relative to the inner cylinder  18 , so that a portion of the baffle  110  may extend beyond the open end  98  and into the flow passage  106 . As the baffle  110  slides beyond the open end  98  (e.g.,  FIG.  10 C ), it obstructs and effectively reduces the area of the flow passage  106 , thereby inhibiting the flow of pressurized gas between the inner chamber  26  and the storage chamber  34 . The baffle  110  is movable between a no-choke position ( FIGS.  9 A and  10 A ) corresponding to a highest power output of the fastener driver  10 , a choked position ( FIGS.  9 C and  10 C ) corresponding to a lowest power output, and one or more partially-choked positions ( FIGS.  9 B and  10 B ) corresponding to an intermediate power output. 
     A control knob  114  is coupled to the baffle  110  via a scotch-yoke mechanism  118  and is operable to slide the baffle  110  in the axial direction relative to the inner cylinder  18 . The scotch-yoke mechanism  118  includes an eccentric pin  122  coupled to the control knob  114  and rotatable therewith. The eccentric pin  122  engages a slot  126  formed in the baffle  110 . As the control knob  114  rotates between the no-choke position ( FIG.  10 A ) and the choked position ( FIG.  10 C ), the eccentric pin  122  engages the slot  126  to adjust the axial position of the baffle  110  relative to the inner cylinder  18 . 
     In operation, the control knob  114  is adjusted to select an appropriate choke position for the throttle mechanism  16 , based on a given fastener driving application. For example, if the given fastener driving application requires a relatively high power output (e.g., for driving fasteners into relatively harder workpieces such as masonry, concrete, etc.), the control knob  114  is rotated to the no-choke position ( FIGS.  9 A and  10 A ). The eccentric pin  122  engages the slot  126  to move the baffle  110  away from the flow passage  106 , such that the baffle  110  vacates the flow passage  106  and does not extend beyond the open end  98 . When a fastener driving sequence is initiated, the compressed gas within the storage chamber  34  flows relatively rapidly through the flow passage  106  unimpeded by the baffle  110 , resulting in the highest power output for the fastener driver  10 . The compressed gas drives the piston  22  and the driver blade  30  to the driven position, thereby driving the fastener into the workpiece. 
     If a subsequent fastener driving application requires a relatively low power output (e.g., for driving fasteners into relatively softer workpieces such as softwood products, engineered wood products, etc.), the control knob  114  is rotated to the full choke position ( FIGS.  9 C and  10 C ). The eccentric pin  122  engages the slot  126  to move the baffle  110  toward the flow passage  106 , such that the baffle  110  extends beyond the open end  98  and constricts the flow passage  106 . When a fastener driving sequence is initiated, the compressed gas within the storage chamber  34  flows relatively slowly through the flow passage  106 , which is constricted by the baffle  110 , resulting in the lowest power output for the fastener driver  10 . The compressed gas drives the piston  22  and the driver blade  30  to the driven position, thereby driving the fastener into the workpiece. 
     If an intermediate power output is desired, the control knob  114  can be rotated to any intermediate position between the no-choke position and the choked position. In some embodiments of the fastener driver  10 , a detent mechanism may be used with the control knob  114  to define a plurality of predefined rotational positions of the control knob  114  coinciding with the no-choke position, the choked position, and one or more intermediate positions. 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described. 
     Various features of the invention are set forth in the following claims.