Patent Publication Number: US-2023149016-A1

Title: Surgical stapling device with firing lockout

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63/278,586 filed Nov. 12, 2021, the entire disclosure of which is incorporated by reference herein. 
    
    
     FIELD 
     This disclosure relates to surgical stapling devices and, more particularly, to a surgical stapling device having a knife and a firing lockout mechanism. 
     BACKGROUND 
     Surgical stapling devices that eject staples to resect or transect tissue during surgical procedures are well known. These stapling devices are available in a variety of configurations including linear, curved, and circular, for performing open and endoscopic surgical procedures. Linear surgical stapling devices for performing open surgical procedures typically include an anvil section, a cartridge receiving section, a staple cartridge, and a firing assembly. The anvil section and the cartridge receiving section are coupled together and movable from an open position to a clamped position to clamp tissue between the staple cartridge and the anvil section. The staple cartridge is releasably secured within the cartridge receiving section, and the firing assembly is movable within the cartridge receiving section to eject the staples from the staple cartridge and to cut the tissue clamped between the staple cartridge and the anvil section. 
     These stapling devices often include a lockout assembly that prevents reclamping of the stapling device after the stapling device has been fired. In certain linear surgical stapling devices, the lockout assembly includes a knife guard that shields the knife and is movable after firing to a position to prevent reclamping of the stapling device. In such devices, the lockout may be susceptible to binding when staples come into contact the lockout assembly. 
     A continuing need exists in the art for a stapling device having a lockout assembly that is less susceptible to binding. 
     SUMMARY 
     This disclosure is directed to a surgical stapling device having an anvil section, a cartridge section, a staple cartridge, a clamping lever, and a firing assembly. The anvil section is coupled to the cartridge section and is movable in relation to the cartridge section between open and clamped positions in response to operation of the clamping lever. The staple cartridge is releasably supported on the cartridge section and includes a lockout assembly and a knife assembly. The knife assembly includes a knife bar having a cutting blade for cutting tissue clamped between the anvil and cartridge sections. The lockout assembly includes a lockout member that movable from an unlocked position to a locked position and is positioned to shield the cutting blade in both positions. The lockout member is configured to prevent binding of the lockout member after the stapling device is fired to ensure movement of the lockout member from the unlocked position to the locked position. In the locked position, the lockout member prevents movement of the anvil section in relation to the cartridge section to the clamped position. 
     Aspects of the disclosure are directed to a stapling device stapling device including an anvil section, a cartridge section, a firing assembly, a clamp member, and a staple cartridge. The anvil section has a proximal portion, a distal portion, and spaced beams. The proximal portion of the anvil section includes a hand grip, and the distal portion of the anvil section includes an anvil plate that is supported on the spaced beams. The cartridge section includes a channel member that defines a channel having a proximal portion and a distal portion. The channel member is adapted to be coupled to the anvil section to facilitate movement of the anvil section in relation to the cartridge section between open and clamped positions. The firing assembly is supported within the proximal portion of the channel and includes a drive beam and a trigger. The clamp member is supported on the cartridge section and is movable from an unclamped position to a clamped position to move the anvil section in relation to the cartridge section from the open position to the clamped position. The staple cartridge is releasably supported within the distal portion of the channel of the channel member of the cartridge section and includes a cartridge body, staples, pushers, an actuation sled, a knife assembly, and a lockout assembly. The cartridge body has a proximal portion and a distal portion and defines a central knife slot and staple receiving pockets positioned on opposite sides of the central knife slot. Each of the staple receiving pockets receives one of the staples and one of the pushers. The actuation sled is positioned within the proximal portion of the cartridge body and is movable through the cartridge body into engagement with the pushers to eject the staples from the staple receiving pockets. The knife assembly includes a knife bar having a cutting member that includes a member body having a distal edge and a cutting blade formed on the distal edge of the member body. The cutting blade is positioned within the knife slot and has an exposed portion that extends above the cartridge body. The lockout assembly includes a lockout member that is pivotably coupled to the proximal portion of the cartridge body and is movable from an unlocked position to a locked position. The lockout member has a base portion that defines a knife slot and includes a blade guard positioned on each side of the knife slot of the base portion. The knife slot of the base portion of the lockout member receives the drive beam of the firing assembly. The blade guards are positioned and configured to shield the exposed portion of the cutting blade when the lockout member is in the unlocked position while leaving the member body of the cutting member exposed. In the locked position, the lockout member obstructs movement of the anvil section in relation to the cartridge section from the open position to the clamped position. 
     Other aspects of the disclosure are directed to a staple cartridge including a cartridge body, staples, pushers, an actuation sled, a knife assembly, and a lockout assembly. The cartridge body has a proximal portion and a distal portion and defines a central knife slot and staple receiving pockets positioned on opposite sides of the central knife slot. Each of the staples is received one of the staple receiving pockets of the cartridge body. Each of the pushers is received within one of the staple receiving pockets of the cartridge body and supports one of the staples. The actuation sled is positioned within the proximal portion of the cartridge body and is movable through the cartridge body into engagement with the pushers to eject the staples from the staple receiving pockets. The knife assembly includes a knife bar that has a cutting member that includes a member body having a distal edge and a cutting blade formed on the distal edge of the member body. The cutting blade is positioned within the knife slot and has an exposed portion extending above the cartridge body. The lockout assembly includes a lockout member that is pivotably coupled to the proximal portion of the cartridge body and is movable from an unlocked position to a locked position. The lockout member has a base portion that defines a knife slot and includes a blade guard positioned on each side of the knife slot. The blade guards are positioned and configured to shield the exposed portion of the cutting blade when the lockout member is in the unlocked position while leaving the member body of the cutting member exposed. 
     In aspects of the disclosure, the staple cartridge includes a biasing member that is positioned to urge the lockout member towards the locked position. 
     In some aspects of the disclosure, the lockout member includes a blocking portion having a support block formed on each side of the knife slot of the base portion, and each of the support blocks has an engagement surface that is positioned to engage one of the spaced beams of the anvil section when the lockout member is in the locked position to prevent movement of the anvil section in relation to the cartridge section from the open position to the clamped position. 
     In certain aspects of the disclosure, the blocking portion has a distal portion positioned over but spaced from the knife bar when the lockout member is in the unlocked position and positioned distally of the knife bar when the lockout member is in the locked position. 
     In aspects of the disclosure, the distal portion of the blocking portion of the lockout member has an arcuate inner surface that faces the knife bar and a linear outer surface. 
     In some aspects of the disclosure, the base portion of the lockout member includes pivot members that are coupled to the cartridge body to pivotably couple the lockout member to the cartridge body. 
     In certain aspects of the disclosure, the biasing member includes a torsion spring that is positioned about one of the pivot members. 
     In aspects of the disclosure, the knife assembly includes a support member that supports the knife bar. 
     In some aspects of the disclosure, the support member is positioned within the cartridge body proximally of the actuation sled and is movable into engagement with the actuation sled to advance the actuation sled through the cartridge body. 
     In certain aspects of the disclosure, the knife bar includes a hook member that is configured to be coupled to the drive beam of the firing assembly when the staple cartridge is positioned within the channel of the channel member. 
     In aspects of the disclosure, the knife bar includes a retainer that engages the lockout member when the lockout member is in the unlocked position to retain the lockout member in the unlocked position. 
     Other aspects, features, and advantages will be apparent from the description, the drawings, and the claims that follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of the disclosure are described herein below with reference to the drawings, wherein: 
         FIG.  1    is a side perspective view of a surgical stapling device according to aspects of the disclosure in a clamped pre-fired position; 
         FIG.  2    is a perspective exploded view of the surgical stapling device shown in  FIG.  1   ; 
         FIG.  3    is a side perspective view of a staple cartridge and shipping wedge of the surgical stapling device shown in  FIG.  2   ; 
         FIG.  4    is an enlarged view of the indicated area of detail shown in  FIG.  5   ; 
         FIG.  5    is a side perspective view of a proximal portion of the staple cartridge shown in  FIG.  3   ; 
         FIG.  6    is a side perspective exploded view of the staple cartridge shown in  FIG.  2   ; 
         FIG.  7    is a side perspective view of a lockout member of the staple cartridge shown in  FIG.  6   ; 
         FIG.  8    is a cross-sectional view taken along section line  8 - 8  of  FIG.  7   ; 
         FIG.  9    is a perspective view from the proximal end of the lockout member shown in  FIG.  7   ; 
         FIG.  10    is a bottom perspective view from the distal end of the lockout member shown in  FIG.  7   ; 
         FIG.  11    is a side perspective view from below of the lockout member shown in FIG. 
         FIG.  12    is a side perspective view from above of the lockout member shown in  FIG.  7   ; 
         FIG.  13    is a cross-sectional view taken through the proximal portion of a channel member and staple cartridge of the surgical stapling device shown in  FIG.  2    in a pre-fired position; 
         FIG.  14    is a side perspective view of the stapling device shown in  FIG.  1    with the anvil section separated from the cartridge section after the stapling device has been fired; 
         FIG.  15    is an enlarged view of the indicated area of detail shown in  FIG.  14   ; 
         FIG.  16    is a side perspective view of the surgical stapling device shown in  FIG.  1    with the cartridge section having a spent or fired staple cartridge as an anvil section is attempted to be coupled to the cartridge section; 
         FIG.  17    is a cross-sectional view taken along section line  17 - 17  of  FIG.  16   ; and 
         FIG.  18    is a side perspective, cutaway view of the central portion of the stapling device shown in  FIG.  16   . 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed surgical device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that aspects of the disclosure are merely exemplary of the disclosure and may be embodied in various forms, Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure. 
     In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel. Further, directional terms such as “front”, “rear”, “upper”, “lower”, “top”, “bottom”, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure. 
     This disclosure is directed to a surgical stapling device that includes an anvil section, a cartridge section, a staple cartridge, a clamping lever, and a firing assembly. The staple cartridge is releasably supported on the cartridge section and includes a lockout assembly and a knife assembly. The anvil and cartridge sections are coupled together and movable from an open position to a clamped position in response to movement of the clamping lever from an unclamped position to a clamped position. The firing assembly is coupled to the knife assembly when the staple cartridge is received within the cartridge section and is movable between a retracted position and an advanced position to eject staples from the staple cartridge and to cut tissue clamped between the staple cartridge and the anvil section. The lockout assembly is supported on the staple cartridge and is movable from an unlocked position to a locked position to prevent reclamping of the anvil and cartridge sections after the stapling device has been fired. The lockout assembly includes a lockout member that is configured to prevent binding of the lockout member to ensure movement of the lockout member from the unlocked position to the locked position after the stapling device is fired and the anvil and cartridge sections are moved to the unclamped position. 
       FIGS.  1  and  2    illustrate a surgical stapling device shown generally as stapling device  10 . The stapling device  10  defines a longitudinal axis “X” ( FIG.  1   ) and includes an anvil section  12 , a cartridge section  14 , a clamping lever  16 , a staple cartridge  18 , a shipping wedge  19  ( FIG.  2   ), and a firing assembly  20 , The cartridge section  14  includes a channel member  22  that has a proximal portion  24  and a distal portion  26  and defines a channel  22   a  that extends through the proximal and distal portions  24  and  26 . The proximal portion  24  of the channel member  22  receives the firing assembly  20 , and the distal portion  26  of the channel  22   a  receives the staple cartridge  18  in a manner to facilitate replacement of the staple cartridge  18  and reuse of the stapling device  10 , The proximal portion  24  of the channel member  22  includes arms  27  that extend upwardly towards the anvil section  12  and define open ended recesses  27   a . A central portion of the channel member  22  includes upwardly extending flanges  29  that define circular cavities  29   a.    
     The anvil section  12  includes spaced beams  12   a  and  12   b  ( FIG.  18   ), an anvil hand grip  28  supported on a proximal portion of the beams  12   a  and  12   b , and an anvil plate  30  supported on a distal portion of the beams  12   a  and  12   b . The anvil plate  30  defines a knife slot  30   a  and faces the cartridge section  14  when the anvil section  12  and the cartridge section  14  are coupled together. The anvil section  12  also includes protrusions  34  that are centrally located on the anvil section  12  and pivot members  36  that are located on a proximal portion of the anvil section  12 . The pivot members  36  are received within the recesses  27   a  of the arms  27  of the channel member  22  to pivotally support the proximal portion of the anvil section  12  on the proximal portion of the cartridge section  14  and facilitate movement of the anvil section  12  in relation to the cartridge section between open and clamped positions. The protrusions  34  are received within the circular cavities  29   a  of the flanges  29  of the channel member  22  when the anvil section  12  is coupled to the cartridge section  14 . In aspects of the disclosure, the pivot members  36  have a tear-shaped configuration although other configurations are envisioned. In the clamped position of the anvil and cartridge sections  12  and  14 , the anvil plate  30  is in juxtaposed relation to the staple cartridge  18 . 
     The clamping lever  16  is pivotally supported on a proximal portion of the cartridge body  14  and is movable between an unclamped position and a clamped position. The clamping lever  16  includes centrally located flanges  40  that are spaced from each other and positioned on opposite sides of the cartridge section  14 . Each of the spaced flanges  40  defines a recess  41  that receives one of the protrusions  34  of the anvil section  12  when the clamp lever  16  is pivoted from an unclamped position to a clamped position to move the protrusions  34  of the anvil section  12  further into the cavities  29   a  of the flanges  29  of the channel member  22  to move the anvil section  12  into juxtaposed alignment with the cartridge section  14  and to clamp tissue between the anvil plate  30  and the staple cartridge  18 . 
       FIG.  2    illustrates the firing assembly  20  which includes a trigger  42  and a longitudinally extending drive beam  44 . The trigger  42  is rotatably supported on a proximal portion of the drive beam  44  and includes a thumb engagement member  42   a  positioned on each side of the stapling device  10 . The thumb engagement member  42   a  is rotatable between two positions to facilitate actuation of the stapling device  10  from both sides of the stapling device  10 . The pivotable trigger  42  is coupled to a proximal portion of the drive beam  44  and is movable longitudinally within the proximal portion  24  of the channel  22   a  of the channel member  22  of the cartridge section  14  to advance the drive beam  44  from a retracted position to an advanced position. The drive beam  44  includes a distal portion that is adapted to engage a knife assembly  50  ( FIG.  4   ) of the staple cartridge  18  when the staple cartridge  18  is received within the distal portion  26  of the channel member  22 . In aspects of the disclosure, the distal portion of the drive beam  44  includes a hook-shaped portion  52  that extends upwardly towards the anvil section  12  and defines a slot  52   a  having an open upper end as viewed in  FIG.  2   . In aspects of the disclosure, the drive beam  44  includes a longitudinally extending rib  44   a  formed along a lower end of the drive beam  44 . The rib  44   b  adds rigidity to the drive beam  44  to prevent buckling of the drive beam  44  during firing of the stapling device  10 . In certain aspects of the disclosure, the rib  44   a  can be formed by rolling the lower end of the drive beam  44  upwardly. Alternately, the rib  44   a  can be formed on or applied to drive beam  44  using a variety of different techniques. 
     A lock member  58  ( FIG.  2   ) is supported within a central portion of the channel  22   a  of the channel member  22  of the cartridge section  14 . The lock member  58  defines a slot  60  (FIG.  2 ) that receives the drive beam  44  to facilitate movement of the drive beam  44  between the retracted and advanced positions. The lock member  58  is pivotable between a locked position in which the lock member  58  is engaged with the drive beam  44  and an unlocked position in which the lock member  58  is positioned to allow the drive beam  44  to move through the slot  60 . In aspects of the disclosure, the lock member  58  is pivotable from the locked position to the unlocked position in response to placement of a staple cartridge  18  within the channel  22   a  in the distal portion  26  of the channel member  22  of the cartridge section. In some aspects of the disclosure, a biasing member (not shown) is engaged with the lock member  58  to urge the lock member  58  towards the locked position. 
       FIGS.  2 - 4    illustrate the staple cartridge  18  which includes a cartridge body  66 , the knife assembly  50 , an actuation sled  68 , pushers  70 , staples  72 , and a lockout assembly  74 , The cartridge body  66  includes a tissue contact surface  66   a  that defines a centrally located knife slot  76  and staple receiving pockets  78  that are positioned on opposite sides of the knife slot  76 . The knife slot  76  extends through the staple cartridge  18  from a proximal end of the staple cartridge  18  to a position adjacent a distal end of the staple cartridge  18 . The knife assembly  50  is movable through the knife slot  76  from a retracted position to an advanced position when the drive bar  44  ( FIG.  2   ) of the firing assembly  20  is advanced from a retracted position to an advanced position to cut tissue clamped between the anvil plate  30  and the staple cartridge  18 . 
     Each of the staple receiving pockets  78  receive one of the staples  72  and one of the pushers  70 . In aspects of the disclosure, the staple receiving pockets  78  are aligned in two or more rows on the opposite sides of the knife slot  76 , e.g., three. The actuation sled  68  is supported within the cartridge body  66  and includes a central rib  80  ( FIG.  4   ) and cam surfaces  82  positioned on opposite sides of the central rib  80 . The central rib  80  is received in the knife slot  76  of the cartridge body  66  and the cam surfaces  82  are aligned with the pushers  70 . The actuation sled  68  is movable from a retracted position to an advanced position within the cartridge body  66  in response to movement drive beam from its retracted position to its distal position into engagement with the pushers  70  to eject the staples  72  from the staple receiving slots  78  of the cartridge body. 
     The staple cartridge  18  also includes a staple guard  80  that is secured to a lower portion of the cartridge body  66  to retain the staples  72  and the pushers  70  within the staple receiving pockets  78  of the cartridge body  66 . In aspects of the disclosure, the staple guard  80  is secured to the cartridge body  66  with a connector  82  that includes spaced flexible detents  82   a . the detents  82   a  extend through cutouts  84  defined in the staple guard  80  and slots  86  formed in a distal portion of the cartridge body  66  to secure the staple guard  80  to the cartridge body  66  in snap-fit fashion. 
     The shipping wedge  19  ( FIG.  3   ) is secured to the tissue contact surface  66   a  ( FIG.  4   ) of the cartridge body  66  and is provided to retain the knife assembly  50  in a retracted position and retain the staples  72  within the cartridge body  66 . In aspects of the disclosure, the shipping wedge  19  includes fins  19   a  ( FIG.  2   ) that are received in the knife slot  76  of the cartridge body  66  to secure the shipping wedge  19  to the cartridge body  66 . When the shipping wedge  19  is secured to the cartridge body  66 , the shipping wedge  19  covers the staple receiving slots  78 . The shipping wedge  19  includes a stop member  19   b  ( FIG.  2   ) that is positioned to prevent advancement of the knife assembly  74  until the shipping wedge  19  is removed from the cartridge body  66 . The shipping wedge  19  includes lateral extensions  19   c  positioned on a distal portion of the shipping wedge  19  and serrations  19   d  positioned on a proximal portion of the shipping wedge  19  that can be grasped by a clinician to remove the shipping wedge  19  from the staple cartridge  18 . 
     The knife assembly  50  includes a support member  90  and a knife bar  92 . The knife bar  92  includes base  94 , a cutting member  96  that extends upwardly from the base  94 , a hook member  98 , and a retainer  100 . The knife bar  92  is secured to the support member  90  such that the knife assembly  50  is movable as a single construct through the cartridge body  66 . The cutting member  96  includes a member body  96   b  that extends upwardly from the base  94  and has a cutting blade  96   a  that is formed on a distal edge of the member body  96 . In aspects of the disclosure, the cutting member  96  extends from the base at an angle such that the uppermost end of the cutting blade  96   a  is position distally of the lowermost end of the cutting blade  96   a . The hook member  98  of the knife bar  92  is formed on a proximal portion of the knife bar  92  and extends downwardly. The hook member  98  is received within the slot  52   a  ( FIG.  2   ) defined by the hook-shaped portion  52  of the drive beam  44  when the staple cartridge  18  is received in the distal portion  26  of the cartridge section  14 . The retainer  100  of the knife bar  92  is positioned on a central portion of the knife bar  92  and extends proximally to define a retaining slot  100   a  that receives a portion of the lockout assembly  74  to retain the lockout assembly  74  in a locked position as described in further detail below. For a more detailed description of the components of the stapling device described above, see, e.g., U.S. Pat. No. 8,505,801 to Ehrenfels et al. 
       FIGS.  4 - 12    illustrate the lockout assembly  74  which includes a lockout member  102  and a biasing member  104 , The lockout member  102  has a base  108  and a blocking portion  110  that is secured to a central portion of the base  108 . The base  108  defines a longitudinal slot  114  ( FIG.  9   ) and includes side walls  108   a , an upper surface  108   b , pivot members  116 , laterally extending wings  118 , and cutting blade guards  120 . The pivot members  116  are formed on a distal portion of the base  108  and extend outwardly from the side walls  108   a . The pivot members  116  are received in openings  122  defined in the proximal portion of the cartridge body  66  of the staple cartridge  18  to pivotally couple the lockout member  102  to the cartridge body  66  such that the lockout member  102  is movable from an unlocked position to a locked position. 
     The laterally extending wings  118  are formed on a proximal portion of the base  108  of the lockout member  102  and extend outwardly of the side walls  108   a  of the base  108  of the lockout member  102 . When the lockout member  102  is in the unlocked position, the wings  118  rest on the beams  12   a  and  12   b  of the anvil section  12  to minimize deflection of the lockout member  102 . 
     In aspects of the disclosure, the proximal portion of the base  108  of the lockout member  102  includes support blocks  119  that are symmetrically positioned on opposite sides of the longitudinal slot  114  on the proximal end of the base  108  of the lockout member  102 . The support blocks  119  include engagement surfaces  119   a  that are substantially vertically oriented and face proximally when the lockout member  102  is in the unlocked position and are substantially horizontally oriented and face the anvil section  12  when the lockout member  102  is in the locked position ( FIG.  18   ). The support blocks  119  include engagement surfaces  119   a  that engage the beams  12   a  and  12   b  of the anvil section when the lockout member  102  is in the locked position and the anvil section  12  is coupled to a cartridge section  14  having a spent or fired staple cartridge  18  to prevent reclamping of the stapling device  10 . The increased surface area provided by the engagement surfaces  119   a  minimizes deflection of the lockout member  102  when the lockout member  102  is in the locked position and an attempt is made to attach an anvil section  12  to the cartridge section  14 . 
     The cutting blade guards  120  are formed on opposite sides of the longitudinal slot  114  on the distal portion of the base  108  of the lockout member  102 . In aspects of the disclosure, the cutting blade guards  120  are triangular and have proximal walls  120   a  that extend in the direction of the cutting blade  96   a  of the cutting member  96  of the knife bar  92 . The cutting blade guards  120  are positioned on opposite sides of the cutting blade  96   a  to shield the cutting blade  96   a . In aspects of the disclosure, the cutting blade guards  120  or positioned distally of the member body  96   b  of the cutting member  96  to minimize any likelihood of staples becoming wedged between the cutting blade guards  120  and the cutting member  96  of the knife bar  92 . 
     The blocking portion  110  includes a body  124  having a proximal portion  124   a , a distal portion  124   b , and a central portion  124   c  ( FIG.  7   ). The central portion  124   c  ( FIG.  7   ) is coupled to or integrally formed with the base  108  of the lockout member  102 . The distal portion  124   b  of the blocking portion  110  has an arcuate inner surface  125   a  and a linear outer surface  125   b . The arcuate inner surface  125   a  has a triangular configuration and includes a central ridge  125   c  and angled walls  125   d  that extend outwardly from the central ridge  125   c . The distal portion  124   b  of the blocking portion  110  and extends over but is spaced from the cutting member  96  of the ( FIG.  6   ) when the knife bar  92  when the lockout member  102  is in the unlocked position. The proximal portion  124   a  of the blocking portion  110  of the lockout member  102  has a distal extension  126  that defines a cavity  126   a  that receives the retainer  100  of the knife bar  92  when the knife bar  92  is in its retracted position. Receipt of the retainer  100  within the cavity  126   a  of the lockout member  102  retains the lockout member  102  in the unlocked position. 
     The biasing member  104  of the lockout assembly  74  is positioned to urge the lockout member  102  towards the locked position. In aspects of the disclosure, the biasing member  104  includes a torsion spring that is positioned about one (or both) of the pivot members  116  of the lockout member  102  to urge the lockout member  102  towards the locked position. Alternately, it is envisioned that the biasing member  104  may have a variety of configurations. 
       FIG.  13    illustrates the proximal portion of the cartridge assembly  14  in a pre-fired condition with the firing assembly  20  and the knife assembly  50  in retracted positions. In the pre-fired condition, the retainer  100  of the knife bar  92  is received within the cavity  126   a  of the blocking portion  110  of the lockout member  102  to retain the lockout member  102  in the unlocked position. In the unlocked position, the upper portion of the cutting blade  96   a  is shielded by the cutting blade guards  120  and the lower position of the cutting blade  96   a  is positioned within the longitudinal slot  114  of the lockout member  102 . The distal portion  124   b  of the blocking portion  110  of the lockout member  102  is positioned over a portion of the member body  96   b  of the cutting member  96  when the lockout member  102  is in the unlocked position. 
     When the stapling device  10  ( FIG.  1   ) is fired by pressing on one of the thumb engagement members  42   a  of the pivotable trigger  42  to move the firing assembly  20  and the knife assembly  50  to their advanced positions, the retainer  100  of the knife bar  92  is removed from the cavity  126  of the lockout member  102  to release the lockout member  102 . When the lockout member  102  is released, the biasing member  104  of the lockout assembly  74  rotates the lockout member  102  in a counterclockwise direction as indicated by arrow “A” in  FIG.  15    towards the locked position. In the locked position, the distal portion  124   b  of the blocking portion  110  of the lockout member  102  extends downwardly from above the knife assembly  50  to a position in front or distally of the cutting blade  96   a  of the knife bar  92  of the knife assembly  50  to shield the cutting blade  96   a  of the knife bar  92 . It is noted that movement of the lockout member  102  from the unlocked position to the locked position is obstructed by the anvil section  12  when the stapling device  10  is in the clamped position. Thus, the lockout member  102  will not move to the locked position until the stapling device  10  is unclamped, i.e., the clamping lever  16  is moved to the unclamped position to space the anvil section  12  from the cartridge section  14 . 
     When the stapling device  10  ( FIG.  1   ) is fired and the knife bar  92  is moved to its advanced position, the actuation sled  68  ( FIG.  13   ) is engaged by the support member  90  ( FIG.  4   ) of the knife assembly  50  and advanced through the cartridge body  66  into engagement with the pushers  70  to eject the staples  72  ( FIG.  4   ) from the cartridge body  66 . As the knife bar  92  of the knife assembly  50  moves through the knife slot  76  of the cartridge body  66 , the cutting blade  96   a  of the cutting member  96 , which projects above the cartridge body  66 , cuts tissue clamped between the anvil section  12  and the cartridge section  14 . 
     After the knife assembly  50  reaches its advanced position, the firing assembly  20  is returned to its retracted position by pushing or pulling the pivotable trigger  42  in a proximal direction. It is noted that the actuation sled  68  is not coupled to the knife assembly  50  and as such will remain in the distal portion of the cartridge body  66  when the firing assembly  20  and knife assembly  50  are returned to their retracted positions. When the knife assembly  50  reaches its retracted position, the retainer  100  of the knife bar  92  is no longer aligned with the cavity  126  of the lockout member  102  which has pivoted towards the locked position. As such, the lockout member  102  can rotate to its locked position when the stapling device  10  is moved to the unclamped position. As illustrated in  FIG.  13   , the arcuate surface  125   a  of the blocking portion  110  of the lockout member  102  is spaced proximally of the cutting member  96  when the lockout member  102  is in its unlocked position. The lockout member  102  will not move to the locked position after the stapling device  10  is fired until the anvil section  12  is spaced from the cartridge section  14  a sufficient distance from the cartridge section  14  to allow the lockout member to pivot. It is noted that the shape of the arcuate surface  125   a  of the lockout member  102  including the angled walls  125   d  directs staples that may be positioned between the cutting member  96  and the arcuate surface  125   a  outwardly of the arcuate surface  125   a  to prevent the staples from becoming trapped between the lockout member  102  and the cutting member  96  which may obstruct movement of the lockout member  102  from the unlocked position to the locked position. 
       FIGS.  14  and  15    illustrate the stapling device  10  with the anvil section  12  separated from the cartridge section  14  after the stapling device  10  has been fired and the firing assembly  20  and the knife assembly  50  are returned to their retracted positions. Separation of the anvil section  12  from the cartridge section  14  allows the lockout member to rotate from the unlocked position towards the locked position and is accomplished by moving the clamping lever  16  in the direction indicated by arrow “B” in  FIG.  14    to the unclamped position as is known in the art. When the lockout member  102  is in the locked position, the proximal portion  124   a  of the blocking portion  110  of the lockout member  102  extends upwardly from the proximal end of the staple cartridge  18  and the distal portion  124   b  of the blocking portion  110  of the lockout member  102  extends downwardly to a position in front of an exposed portion of the cutting blade  96   a  ( FIG.  17   ). 
       FIGS.  16 - 18    illustrate the stapling device  10  as the anvil section  12  is attempted to be coupled to a cartridge section  14  having a spent or fired staple cartridge  18 . As described above, after the anvil section  12  is separated from the cartridge section  14  and the lockout member  102  is pivoted to the locked position, the proximal portion  124   a  of the lockout member  102  projects upwardly from the cartridge body  66  of the staple cartridge  18 . When an anvil section  12  is coupled to a cartridge section  14  having a spent staple cartridge  18 , the proximal portion of the blocking member  110  of the locking member  102  is received between the spaced beams  12   a  and  12   b  of the anvil section  12  ( FIG.  18   ) and the engagement surfaces  119   a  of the support blocks  119  of the lockout member  102  engage the beams  12   a  and  12   b  to prevent reclamping of the stapling device  10 . In some aspects of the disclosure, the proximal portion  124   a  of the blocking member  110  of the lockout member  102  defines an abutment surface  150  that engages an inner surface  152  ( FIG.  17   ) of the anvil section  12  to assist in preventing approximation of the anvil section  12  with the cartridge section  14 . 
     Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly, shown and described, except as indicated by the appended claims.