Patent Publication Number: US-11034005-B2

Title: Dry-fire lockout mechansim for a powered fastener driver

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/540,709 filed on Aug. 3, 2017, the entire content of which is incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to powered fastener drivers, and more specifically to a dry-fire lockout mechanism for a powered fastener driver. 
     BACKGROUND OF THE INVENTION 
     Powered fastener drivers are typically used to drive fasteners (e.g., nails, staples, tacks, etc.) into a workpiece. These powered fastener drivers operate utilizing a relatively large driving force from various means known in the art (e.g. compressed air generated by an air compressor, electrical energy, etc.) to drive the fasteners into the workpiece. These designs may include dry-fire lockouts to prevent the powered fastener driver from actuating when no fasteners remain. 
     SUMMARY OF THE INVENTION 
     The present invention provides, in one aspect, a powered fastener driver including a magazine configured to receive fasteners, a pusher slidably coupled to the magazine, a nosepiece coupled to the magazine, and a workpiece contact element movable with respect to the nosepiece. The powered fastener driver further includes a lockout member pivotally coupled to the nosepiece, and a magnet exerting a magnetic force on the lockout member to bias the lockout member toward a first position. The pusher moves the lockout member to a second position where the lockout member blocks movement of the workpiece contact element when a predetermined number of fasteners remain in the magazine. 
     The present invention provides, in another aspect, a powered fastener driver including a magazine configured to receive fasteners and a pusher slidably coupled to the magazine. The pusher includes a pin. The powered fastener driver further includes a nosepiece coupled to the magazine, a workpiece contact element movable with respect to the nosepiece, and a lockout member pivotally coupled to the nosepiece. The lockout member includes a first end engageable with the pin, a second end opposite the first end, and at least a portion formed of a ferromagnetic material. The powered fastener driver further includes a cover coupled to the nosepiece, the cover defining a magnet holder, and a magnet coupled to the cover by the magnet holder. The magnet exerts a magnetic force on the lockout member to bias the lockout member toward a first position, and the pin engages the first end of the lockout member when a predetermined number of fasteners remain in the magazine. The pin rotates the lockout member to a second position where the second end of the lockout member blocks movement of the workpiece contact element when the predetermined number of fasteners remain in the magazine. 
     Other features and aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a portion of a powered fastener driver including a nosepiece assembly for driving fasteners. 
         FIG. 2  is a partial perspective view of the nosepiece assembly of  FIG. 1  illustrating a dry-fire lockout mechanism. 
         FIG. 3  is a front view of the nosepiece assembly of  FIG. 2 . 
         FIG. 4  is a side view of the nosepiece assembly of  FIG. 2  illustrating a workpiece contact element. 
         FIG. 5  is another side view of the nosepiece assembly of  FIG. 2  illustrating a pin coupled to a fastener pusher system. 
         FIG. 6  is an exploded view of the nosepiece assembly of  FIG. 1  including a cover, a front plate, a lockout member of the dry-fire lockout mechanism, and a pusher. 
         FIG. 7  is a perspective view of the cover of  FIG. 6 . 
         FIG. 8  is a perspective view of the front plate of  FIG. 6 . 
         FIG. 9  is a perspective view of the lockout member of  FIG. 6 . 
         FIG. 9A  is a perspective view of another lockout member including an insert formed of ferromagnetic material. 
         FIG. 10  is a perspective view of the pusher of  FIG. 6 . 
         FIG. 11A  is a cross-sectional view of the nosepiece assembly of the fastener driver taken along lines  11 A- 11 A of  FIG. 2 , illustrating a first position of the dry-fire lockout mechanism. 
         FIG. 11B  is a cross-sectional view of the nosepiece assembly of the fastener driver similar to  FIG. 11A , illustrating a second position of the dry-fire lockout mechanism. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     With reference to  FIG. 1 , a powered fastener driver is operable to drive fasteners (e.g., nails, staples, tacks, etc.) held within a magazine assembly  10  into a workpiece. In other words, the magazine assembly  10  includes a magazine  14  having a magazine body  18  configured to receive the fasteners to be driven into the workpiece by the powered fastener driver. The fastener driver generally includes a body, a handle coupled to the body, and a trigger (not shown) for operating the fastener driver. The body of the powered fastener driver may further include other elements for operating the powered fastener driver (i.e. air compressor, electronics, springs etc.). The magazine body  18  has a first end  22  and a second end  24  opposite the first end  22 . The magazine body  18  further includes a first side  26  and a second side  28  ( FIG. 5 ) opposite the first side  26 . 
     A nosepiece assembly  30  is positioned at the first end  22  of the magazine body  18 . The nosepiece assembly  30  generally includes a front plate  34  coupled to the first end  22  of the magazine body  18 , a cover  40  coupled to the front plate  34 , and a workpiece contact element  46  movable with respect to the front plate  34 . The front plate  34  is oriented substantially perpendicular to the magazine body  18 . Furthermore, the front plate  34  includes a first, lower flange  36  and a second, upper flange  38  opposite the first flange  36 . 
     With continued reference to  FIG. 1 , the cover  40  substantially covers the front plate  34 . In the illustrated embodiment, the cover  40  extends from the first flange  36  to the second flange  38  of the front plate  34 . The cover  40  includes a first end  42  and a second end  44  corresponding to the first flange  36  and the second flange  38  of the front plate  34 . The cover  40  may be coupled to the front plate  34  using a fastener (not shown) such as a bolt, screw, etc. Furthermore, the cover  40  is generally tapered from the second end  44  to the first end  42 . 
     With reference to  FIGS. 2-6 , the magazine assembly  10  further includes a pusher  50  ( FIG. 5 ) and a lower guide  52  positioned within the magazine body  18 . The illustrated pusher  50  and the lower guide  52  are positioned at the first end  22  of the body  18 . The lower guide  52  of the magazine  14  is positioned adjacent the first flange  36  of the front plate  34 . With reference to  FIG. 10 , the illustrated pusher  50  includes a pusher bracket  54  and a pin  56  coupled to a side of the pusher bracket  54  (i.e. the side opposite the side of the fastener driver  10  having the workpiece contact element  46 ). In other embodiments, the pin  56  may be coupled to the same side as the workpiece contact element  46 . Furthermore, the pusher bracket  54  is positioned near the upper flange  38  of the front plate  34  ( FIG. 5 ). 
     With reference to  FIG. 10 , the pin  56  includes a first end  62  and a second end  66 . The illustrated pin  56  is coupled to the side of the pusher bracket  54  by a support  58 . More specifically, the second end  66  of the pin  56  is coupled to the support  58  ( FIG. 5 ). The pusher  50  is slidably coupled to the magazine body  18  and biases any fasteners contained within the magazine  14  toward the front plate  34  of the nosepiece assembly  30 . 
     With reference to  FIGS. 2-6 , the workpiece contact element  46  of the nosepiece assembly  30  extends from the lower flange  36  to the upper flange  38  of the front plate  34  (FIGS.  2 - 3 ) and includes a plurality of interconnected segments  70 . The illustrated workpiece contact element  46  includes generally four segments  70  in which adjacent segments are coupled by a bend  80 . In particular, a first segment  72  of the workpiece contact element  46  is positioned below the second flange  38  of the front plate  34 . A second segment  74  is coupled to the first segment  72  by one of the bends  80 . The second segment  74  extends perpendicular to the first segment  72 . Similarly, one of the bends  80  couples the second segment  74  to a third segment  76 . The second and third segments  74 ,  76  are positioned near the first side  26  of the magazine body  18 . In addition, the second and third segments  74 ,  76  are perpendicular to each other ( FIGS. 2-3 ). Likewise, the third segment  76  is coupled to a fourth segment  78  by one of the bends  80 . The fourth segment  78  is perpendicular to the third segment  76 . The fourth segment  78  is at least partially enclosed by the cover  40 . Furthermore, the fourth segment  78  has a tip  84  that extends through the first end  42  of the cover ( FIG. 1 ). In the illustrated embodiment, the fourth segment  78  is positioned between the first flange  36  of the front plate  34  and the first end  42  of the cover  40  of the nosepiece assembly  30  ( FIG. 1 ). The fourth segment  78  of the workpiece contact element  46  further includes a cap  88  (i.e., a no-mar pad) enclosing the tip  84  of the fourth segment  78  ( FIGS. 2-3 ). The tip  84  including the cap  88  of the fourth segment  78  is configured to engage a surface of the workpiece. 
     With continued reference to  FIGS. 2-6 , the fourth segment  78  of the workpiece contact element  46  includes a first edge  96  having the tip  84  and a second, opposite edge  98  ( FIG. 3 ). The fourth segment  78  of the workpiece contact element  46  defines a longitudinal axis  100 . Specifically, the longitudinal axis  100  extends from the first edge  96  to the second edge  98  of the fourth segment  78  ( FIGS. 2-3 ). Furthermore, the second edge  98  defines a recess  94  ( FIGS. 2-3 ), as discussed in greater below. The workpiece contact element  46  is moveable with respect to the front plate  34  along the first axis  100 . In other words, the workpiece contact element  46  may translate with respect to the front plate  34  along the first axis  100  when the tip  84  is depressed against the workpiece. 
     With continued reference to  FIGS. 2-6 , an inner surface  116  of the front plate  34  of the nosepiece assembly  30  defines cylindrical apertures  120 . The illustrated front plate  34  includes two apertures  120  positioned on the second flange  38  of the front plate  34  and two apertures  120  positioned between the first flange  36  and the second flange  38  of the front plate  34  ( FIG. 3 ). In other embodiments, the front plate  34  may define at least one or more apertures  120 . The cover  40  defines apertures  120  corresponding to the apertures  120  defined by the front plate  34  ( FIG. 6 ). The cylindrical apertures  120  are configured to receive fasteners. The fasteners are configured to secure the cover  40  to the front plate  34  of the nosepiece assembly  30 . In other embodiments, the cover  40  may be coupled to the front plate  34  at any desired location between the first flange  36  and the second flange  38  of the front plate  34  and may use any number of fasteners to secure the cover  40  to the front plate  34 . 
     With continued reference to  FIGS. 2-6 , the inner surface  116  of the front plate  34  of the nosepiece assembly  30  further includes first and second extensions  124 ,  128  positioned near the tip  84  of the workpiece contact element  46  ( FIGS. 2-3 ). In particular, the first and second extensions  124 ,  128  are positioned on opposite sides of the fourth segment  78  of the workpiece contact element  46 . Furthermore, the illustrated second extension  128  has a guide projection  132  extending over a top  136  of the fourth segment  78  of the workpiece contact element  46 . The first and second extensions  124 ,  128  and the guide projection  132  are configured to guide the fourth segment  78  as the workpiece contact element  46  translates along the first axis  100 . 
     With continued reference to  FIGS. 2-6 , the powered fastener driver further includes a dry-fire lockout assembly  150 . The dry-fire lockout assembly  150  includes a first mounting flange  154 , a second mounting flange  158 , a base  162 , a lockout member  166  pivotally coupled to the first and second flanges  154 ,  158  by an axle  170 , and a magnet  200  ( FIG. 6 ) positioned near the lockout member  166 . The first and second mounting flanges  154 ,  158  extend from the inner surface  116  of the front plate  34  ( FIG. 2 ). The axle  170  defines a second, pivot axis  110  that extends through the first and second mounting flanges  154 ,  158  and the lockout member  166 . The first and second axes  100 ,  110  are substantially parallel ( FIGS. 2-3 ). The dry-fire lockout assembly further includes a clip  174  coupled to an end  178  ( FIG. 6 ) of the axle  170  to secure the axle to the mounting flanges  154 ,  158 . The base  162  is positioned adjacent the lockout member  166  and coupled to the axle  170 . The base  162  has a protrusion  164  extending from the base  162  ( FIG. 6 ), as further discussed below. The base  162  may be an elastic support for the lockout member  166 . Specifically, the base  162  may be configured to help absorb impact on the lockout member  166  from the workpiece contact element  46  in order to minimize the risk of bending of the lockout member  166 . 
     With reference to  FIGS. 2-6 , the first and second mounting flanges  154 ,  158  include apertures  182  configured to receive the axle  170  ( FIG. 8 ). The first and second mounting flanges  154 ,  158  are configured to hold the axle  170  above the inner surface  116  of the front plate  34 . As such, the axle  170  is configured to allow pivoting of the lockout member  166  held above the inner surface  116 . In other words, the lockout member  166  is pivotally coupled to the front plate  34  by the axle  170  received between the first and second mounting flanges  154 ,  158 . 
     With reference to  FIGS. 9 and 9A , the lockout member  166  includes a first end  190  coupled for pivoting about the axle  170  and a second end  194  opposite the first end  190  ( FIG. 3 ). As described above, the first end  190  of the lockout member  166  pivots about the second, pivot axis  110 . Moreover, the lockout member  166  is oriented from the first end  190  to the second end  194  substantially perpendicular to the first and second axes  100 ,  110  ( FIG. 3 ). Therefore, the lockout member  166  is substantially perpendicular to the fourth segment  78  of the workpiece contact element  46  defining the first axis  100 , as further discussed below. The lockout member  166  includes at least a portion formed of a ferromagnetic material. In an alternative embodiment, as shown in  FIG. 9A , the lockout member  166 ′ may further include an insert  188  formed of a ferromagnetic material. 
     With reference to  FIG. 7 , the cover  40  partially defines a cavity  204  when the cover  40  is coupled to the front plate  34 . The dry-fire lockout mechanism  150  may extend from the inner surface  116  of the front plate  34  into the cavity  204  defined by the cover  40 . Furthermore, the cover  40  defines a magnet holder  212  extending from an inner surface  208  of the cover  40  into the cavity  204 . 
     With reference to  FIGS. 6 and 7 , the dry-fire lockout mechanism  150  further includes the magnet  200  receivable within the magnet holder  212 . In the illustrated embodiment, the magnet holder  212  includes legs  216  extending from the inner surface  208  of the cover  40 . The legs  216  define a slot  220  in which the magnet  200  is received. In other words, the magnet holder  212  is configured to receive the magnet  200  within the slot  220 . In other embodiments, the magnet holder  212  may be positioned on the inner surface  116  of the front plate  34 . Furthermore, the magnet holder  212  may extend into the cavity  204  adjacent the lockout member  166  of the dry-fire lockout mechanism  150 . The magnet  200  is positioned adjacent the lockout member  166  within the magnet holder  212  when the cover  40  is coupled to the front plate  34 . Furthermore, the magnet  200  is positioned offset from the second pivot axis  110 . The magnet  200  is configured to exert a magnetic biasing force on the ferromagnetic material of the lockout member  166 , as further discussed below. 
     With reference to  FIGS. 6 and 8 , the inner surface  116  of the front plate  34  further defines first and second apertures  224 ,  228 . The first and second apertures  224 ,  228  are positioned on the inner surface  116  between the first and second mounting flanges  154 ,  158 . The first aperture  224  is configured to receive the pin  56  of the pusher  50 , as further discussed below. The second aperture  228  is configured to receive the protrusion  164  of the base  162 . 
     With continued reference to  FIG. 8 , the front plate  34  further defines a notch  232  positioned on the side of the nosepiece assembly  30  having the workpiece contact element  46  (i.e. the first side  26  of the magazine body  18 ). The third segment  76  of the workpiece contact element  46  extends from the second segment  74  through the notch  232  ( FIG. 1 ). Furthermore, the cover  40  encloses the notch  232  when coupled to the front plate  34  ( FIG. 1 ). 
     With reference to  FIG. 9 , the first end  190  of the lockout member  166  further includes a lip  240 . The first end  62  of the pin  56  of the pusher  50  is configured to engage the lip  240  when a predetermined number (e.g., 0, 1, 2, etc.) of fasteners remain in the magazine  14 . Specifically, the second end  66  of the pin  56  extends through the first aperture  224  in the front plate  34  when the predetermined number of fasteners remain in the magazine  14  ( FIG. 11B ). In some embodiments, the predetermined number of fasteners may be zero. In other embodiments, the predetermined number of fasteners may be 1, 2, 3, etc. The second end  194  of the lockout member  166  is positioned adjacent the second edge  98  of the fourth segment  78  of the workpiece contact element  46 . In addition, the recess  94  defined in the workpiece contact element  46  is configured to receive the second end  194  of the lockout member  166 , as further discussed below. 
     With reference to  FIG. 10 , a top surface  244  of the pusher bracket  54  is facing towards the front plate  34 . A channel  248  ( FIG. 8 ) is formed between the lower guide  52  coupled to the pusher bracket  54  and a bottom surface  252  of the front plate  34  ( FIG. 6 ). The channel  248  is configured to receive the fasteners when driving into the workpiece. 
     With reference to  FIG. 11A , the lockout member  166  is magnetically biased to a first position (i.e., a non-blocking position) by the magnet  200  when fasteners remain in the magazine  14 . Specifically, when in the first position, the second end  194  of the lockout member  166  extends toward (i.e., is oriented towards, in a facing relationship with) the magnet  200 . Furthermore, with the lockout member  166  in the first position, the workpiece contact element  46  (i.e. the fourth segment  78 ) is able to slide past the lockout member  166 , allowing for actuation of the powered fastener driver. 
     With reference to  11 B, the lockout member  166  is moved (i.e. pivoted) to a second, blocking position by the pusher  50  engaging the lockout member  166 . The magnet  200 , received in the magnet holder  212 , is positioned adjacent the lockout member  166  within the cavity  204 . Specifically, the pusher  50  is configured to move the lockout member  166  toward the second position against the magnetic bias of the magnet  200  when the predetermined number of fasteners remain in the magazine  14 . As such, the second end  194  of the lockout member  166  is positioned farther from the magnet  200  when in the second position than when the lockout member  166  is in the first position ( FIG. 11B ). In particular, the lockout member  166  is substantially perpendicular to the longitudinal axis  100  of the fourth segment  78  of the workpiece contact element  46 . The second end  194  of the lockout member  166  is received within the recess  94  when the lockout member  166  is in the blocking position. More specifically, the lockout member  166  is received within the recess  94  when the workpiece contact element  46  is displaced to abut the lockout member  166 . 
     With continued reference to  FIGS. 11A and 11B , the lockout member  166  pivots about the second axis  110 , allowing the lockout member  166  to pivot between the first position ( FIG. 11A ) and the second position ( FIG. 11B ). The first end  190  of the lockout member  166  is engaged by the pin  56  of the pusher  50  in the second position. The second end  194  of the lockout member  166  is configured to block the movement of the workpiece contact element  46  in the second position. In some embodiments, the movement of the workpiece contact element  46  along the axis  100  is stopped completely by the second end  194  of the lockout member  166 . 
     In operation, when fasteners remain in the magazine  14 , the pusher  50  biases the fasteners toward the first flange  36  of the front plate  34  of the nosepiece assembly  30  where they are driven into a workpiece by actuation of the fastener driver. With fasteners in the magazine  14 , the lockout member  166  is biased toward the first position ( FIG. 11A ) by the magnet  200 , which allows for the workpiece contact element  46  to slide with respect to the front plate  34  of the nose piece assembly  30  to enable actuation of the fastener driver. 
     When the predetermined number of fasteners remain in the magazine  14 , the pin  56  of the pusher  50  extends through the first aperture  224  in the front plate  34  and engages the first end  190  of the lockout member  166 . The pusher  50  pivots the lockout member  166  about the axis  110  from the first position ( FIG. 11A ) to the second position ( FIG. 11B ). In other words, the pusher  50  overcomes the magnetic force exerted by the magnet  200  on the second end  194  of the lockout member  166  to pivot the lockout member  166  to the second position when the predetermined number of fasteners remain in the magazine  14 . When the lockout member  166  is in the second position, movement of the workpiece contact element  46  is blocked in order to prevent further activation of the powered fastener driver. In some embodiments, the lockout member  166  pivots to the second position when no fasteners remain in the magazine  14  (i.e., the predetermined number is zero). In other embodiments, the lockout member  166  pivots to the second position when a small number of fasteners (e.g., 1, 2, 3, etc.) remain in the magazine (i.e., the predetermined number is 1, 2, 3, etc.). 
     As such, the lockout member  166  of the dry-fire lockout mechanism  150  is operable to pivot from the first position to the second position when the predetermined number of fasteners remain in the magazine  14 . With the lockout member  166  blocking the movement of the workpiece contact element  46 , dry-firing of the powered fastener driver is prevented. 
     Various features and advantages of the invention are set forth in the following claims.