Patent Publication Number: US-2022211371-A1

Title: Surgical stapling device with firing lockout mechanism

Description:
FIELD 
     The disclosure is directed to surgical stapling devices and, more particularly, to surgical stapling devices with lockout mechanisms to prevent firing of the stapling device with a spent staple cartridge. 
     BACKGROUND 
     Surgical stapling devices for simultaneously stapling and cutting tissue are well known in the art. Typically, these stapling devices include a tool assembly and a drive assembly. The tool assembly includes an anvil assembly and a cartridge assembly. The cartridge assembly includes a channel member and a staple cartridge that includes a cartridge body, a knife, and an actuation sled. The drive assembly is movable in relation to the anvil and cartridge assemblies to advance the actuation sled and knife through the staple cartridge to move the tool assembly between open and clamped positions, to eject staples from the staple cartridge, and cut tissue clamped between the anvil and cartridge assemblies. After the stapling device is fired, the actuation sled remains in an advanced position within the tool assembly. 
     In some stapling devices, the staple cartridge is removably received within the channel member of the cartridge assembly and is replaceable to facilitate reuse of the stapling device. In order to prevent actuation of the tool assembly after the staples have been fired from the staple cartridge, the tool assembly may include a lock mechanism that is movable from an unlocked position to a locked position into engagement with the drive assembly when the sled is in its advanced position to prevent readvancement of the drive assembly. In some stapling devices, the lock mechanism is movable to the unlocked position in response to insertion of a new or unfired staple cartridge into the channel member. 
     A continuing need exists for a lock mechanism of simple construction that can prevent advancement of a drive assembly of a stapling device when a spent staple cartridge is positioned within the channel member of the cartridge assembly. 
     SUMMARY 
     This disclosure is directed to a surgical stapling device having a tool assembly that includes an anvil and a cartridge assembly that are movable in relation to each other between open and clamped positions. The anvil supports a lock mechanism that includes a lock member that moves from a locked position to an unlocked position in response to movement of the tool assembly from the open position to the clamped position. 
     One aspect of the disclosure is directed to a surgical stapling device including an elongate body, a tool assembly, a lock mechanism, and a drive assembly. The elongate body has a proximal portion and a distal portion. The tool assembly is supported on the distal portion of the elongate body and includes a cartridge assembly and an anvil. The cartridge assembly includes a channel member and a staple cartridge. The staple cartridge is removably received within the channel member and includes a cartridge body, staples, and an actuation sled assembly including an actuation sled. The actuation sled assembly is movable through the cartridge body between retracted and advanced positions. The anvil includes a body that is coupled to the cartridge assembly such that the tool assembly is movable between open and clamped positions. The lock mechanism is supported on the anvil and includes a lock member that is rotatable between a locked position and an unlocked position in response to movement of the tool assembly from the open position to the clamped position. The drive assembly includes a clamp member that is movable in relation to the tool assembly between retracted and advanced positions. The lock member is positioned to prevent movement of the clamp member from the retracted position to the advanced position in the locked position. 
     In aspects of the disclosure, the lock member is biased towards the locked position. 
     In some aspects of the disclosure, the lock mechanism includes a biasing member to urge the lock member towards the locked position. 
     In certain aspects of the disclosure, the biasing member includes a coil spring. 
     In aspects of the disclosure, the actuation sled assembly includes a knife that is supported on the actuation sled. 
     In some aspects of the disclosure, the lock member engages the actuation sled assembly when the actuation sled assembly is in its retracted position to retain the lock member in the unlocked position. 
     In certain aspects of the disclosure, the lock member engages the knife of the actuation sled assembly when the actuation sled assembly is in its retracted position to retain the lock member in the unlocked position. 
     In aspects of the disclosure, the lock member includes a circular hub portion and the anvil body defines a recess having a cylindrical portion. 
     In some aspects of the disclosure, the circular hub portion of the lock member is received within the cylindrical portion of the recess to rotatably support the lock member on the anvil body. 
     In certain aspects of the disclosure, the lock mechanism includes a pin that engages the lock member to retain the lock member within the recess in the anvil body. 
     In aspects of the disclosure, the lock member includes an arm and an abutment member. 
     In some aspects of the disclosure, the circular hub portion is positioned on a distal portion of the arm and the abutment member is positioned on a proximal portion of the arm. 
     In certain aspects of the disclosure, the abutment member has an abutment surface that engages the clamp member when the lock member is in the locked position. 
     In aspects of the disclosure, the lock member is molded from plastic. 
     In some aspects of the disclosure, the locked member is stamped from sheet metal. 
     In certain aspects of the disclosure, the anvil body includes an overhang that is positioned over the recess to retain the lock member within the recess. 
     Another aspect of this disclosure is directed to an anvil assembly including an anvil and a lock mechanism. The anvil includes an anvil body having a staple forming surface defining staple forming pockets and a longitudinal slot. The staple forming pockets are positioned on opposite sides of the longitudinal slot. The lock mechanism is supported on the anvil body and includes a lock member that is rotatable between a locked position and an unlocked position. In the locked position, the lock member extends at least partially across the longitudinal slot. 
     Other features of the disclosure will be appreciated from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of the disclosure are described herein below with reference to the drawings, wherein: 
         FIG. 1  is side perspective view of a surgical stapling device including a tool assembly having a locking mechanism according to aspects of the disclosure with the tool assembly in an open position; 
         FIG. 2  is an enlarged view of the indicated area of detail shown in  FIG. 2 ; 
         FIG. 3  is a side perspective view the tool assembly shown in  FIG. 2  with the tool assembly in a clamped position; 
         FIG. 4  is a side perspective view of a clamp member of a drive assembly of the stapling device shown in  FIG. 1 ; 
         FIG. 5  is a side perspective view of a knife and actuation sled of the tool assembly shown in  FIG. 3 ; 
         FIG. 6  is a side perspective view of the clamp member, actuation sled, and knife shown in  FIGS. 4 and 5  with the clamp member engaged with the actuation sled; 
         FIG. 7  is a perspective view of the anvil of the tool assembly shown in  FIG. 3  with a lock mechanism secured to the anvil; 
         FIG. 8  is a perspective view of the anvil and lock mechanism shown in  FIG. 7  with the lock mechanism separated from the anvil; 
         FIG. 9  is a side perspective view from a first side of a lock member of the lock mechanism shown in  FIG. 8 ; 
         FIG. 10  is a side perspective view from a second side of the lock member of the lock mechanism shown in  FIG. 8 ; 
         FIG. 11  is a cross-sectional view taken along section line  11 - 11  of  FIG. 7 ; 
         FIG. 11A  is a perspective view of another alternate version of the anvil and lock mechanism of the tool assembly of the stapling device shown in  FIG. 1 ; 
         FIG. 12  is a side perspective view of the clamp member, the actuation sled, and the lock mechanism of the tool assembly shown in  FIG. 9  with the lock mechanism in an unlocked position; 
         FIG. 13  is a plan view of a proximal portion of the tool assembly with an anvil body of the anvil removed and the lock mechanism in an unlocked position; 
         FIG. 14  is a cross-sectional view taken along section line  14 - 14  of  FIG. 12 ; 
         FIG. 15  is a side perspective view of the clamp member, the actuation sled, and the lock mechanism of the tool assembly shown in  FIG. 12  with the lock mechanism in a locked position; 
         FIG. 16  is a cross-sectional view taken along section line  16 - 16  of  FIG. 15 ; 
         FIG. 17  is a perspective view of an alternate version of the anvil and lock mechanism of the tool assembly of the stapling device shown in  FIG. 1 ; 
         FIG. 18  is a perspective view of the anvil and lock mechanism shown in  FIG. 17  with the lock mechanism separated from the anvil; and 
         FIG. 19  is a side perspective view of an alternate version of the lock member of the lock mechanism shown in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed stapling 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 addition, directional terms such as front, rear, upper, lower, top, bottom, distal, proximal, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure. 
     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. 
     The disclosed surgical stapling device includes a tool assembly and a drive assembly for actuating the tool assembly. The tool assembly includes an anvil and a cartridge assembly that are movable in relation to each other between open and clamped positions. The cartridge assembly includes a channel member and a staple cartridge that is releasably received within the channel member and replaceable to facilitate reuse of the stapling device. The staple cartridge includes a cartridge body, and an actuation sled assembly which may include a knife. The drive assembly includes a clamp member that is movable through the cartridge body from a retracted position to an advanced position. Movement of the clamp member from its retracted position to its advanced position advances the actuation sled assembly though the cartridge body to move the tool assembly from the open position to the clamped position and to eject staples from the staple cartridge. The anvil supports a lock mechanism that forms an anvil assembly with the anvil. The lock mechanism includes a lock member that is movable from a locked position to an unlocked position in response to movement of the tool assembly from the open position to the clamped position. In the locked position, the lock mechanism obstructs movement of the drive assembly from its retracted to its advanced position to prevent operation of the stapling device.  FIGS. 1-3  illustrate a surgical stapling device according to aspects of the disclosure shown generally as stapling device  10  which includes a handle assembly  12 , an elongate body  14 , and a tool assembly  100 . The elongate body  14  defines a longitudinal axis “X” ( FIG. 1 ). The handle assembly  12  includes a body  18  that defines a hand grip  18   a , a plurality of actuator buttons  20 , a rotation knob  22 , and an articulation lever  24 . The rotation knob  22  is rotatably supported on a distal portion of the body  18  of the handle assembly  12  and supports the elongate body  14  to facilitate rotation of the elongate body  14  and the tool assembly  100  in relation to the handle assembly  12  about the longitudinal axis “X”. The actuator buttons  20  control operation of the various functions of the stapling device  10  including approximation, firing, and cutting. The articulation lever  24  is rotatably supported on the rotation knob  22  and is pivotable to effect articulation of the tool assembly  100  in relation to the elongate body  14  about an axis transverse to the longitudinal axis “X” of the elongate body  14 . Although the stapling device  10  is illustrated as an electrically powered stapling device, it is envisioned that the disclosed tool assembly  100  would also be suitable for use with manually powered surgical stapling devices and robotically actuated stapling devices. U.S. Pat. No. 9,055,943 discloses a surgical stapling device including a powered handle assembly and U.S. Pat. No. 6,241,139 discloses a surgical stapling device including a manually actuated handle assembly. U.S. Pat. No. 9,962,159 discloses a stapling device that is configured for use with a robotic system. 
       FIGS. 2 and 3  illustrate the tool assembly  100  which includes an anvil  102  and a cartridge assembly  104 . The cartridge assembly  104  includes a staple cartridge  106  and a channel member  108  that receives the staple cartridge  106 . In aspects of the disclosure, the staple cartridge  106  is releasably supported within the channel member  108  and is replaceable to facilitate reuse of the tool assembly  100 . The staple cartridge  106  includes a cartridge body  110 , an actuation sled  112  ( FIG. 5 ), and a plurality of staples  114  ( FIG. 13 ). The cartridge body  110  defines a central knife slot  116  and staple receiving pockets  118 . In aspects of the disclosure, the staple receiving pockets  118  are aligned in rows positioned on each side of the central knife slot  116 . Although three rows of staple receiving pockets  118  are shown in  FIG. 2  on each side of the central knife slot  116 , it is envisioned that the cartridge body  110  may define one or more rows of staple receiving pockets  118  on each side of the central knife slot  116 . Each of the staple receiving pockets  118  receives a staple  114  ( FIG. 13 ). Although not shown, the staple cartridge  104  also includes pushers that support the staples  114  and are engaged by the actuation sled  112  ( FIG. 5 ) as the actuation sled  112  is advanced through the cartridge body  110  to eject the staples  114  from the cartridge body  110 . In aspects of the disclosure, the actuation sled  112  includes angled cam surfaces  112   a  ( FIG. 5 ) that engage and lift the pushers (not shown) within the cartridge body  110  of the staple cartridge  104  to eject the staples  114  from the cartridge body  110 . 
       FIGS. 4-6  illustrate the actuation sled  112  of the staple cartridge  106  and a clamp member  152  of a drive assembly of the stapling device  10  ( FIG. 1 ). In aspects of the disclosure, the actuation sled  112  supports a knife  120  to form an assembly that is movable through the cartridge body  110  from a retracted position to an advanced position. The knife  120  includes a longitudinal body portion  122  and a vertically positioned cutting member  124  that extends from the body  122  through the central knife slot  116  ( FIG. 2 ) in the cartridge body  110  towards the anvil  102 . 
       FIGS. 7 and 8  illustrate the anvil  102  of the tool assembly  100  which includes an anvil body  130  that has a proximal portion and a distal portion. The distal portion of the anvil body  130  has a staple forming surface  136  that defines staple forming pockets  136   a . The staple forming surface  136  is movable into juxtaposed alignment with the staple cartridge  106  ( FIG. 3 ) when the tool assembly  100  is moved from the open position to the clamped position to position the staple forming pockets  136   a  in juxtaposed alignment with the staple receiving pockets  118  ( FIG. 2 ) of the staple cartridge  106 . The anvil body  130  defines a channel  138  and a longitudinal slot  140  that communicates with the channel  138 . The channel  138  has a proximal portion that is defined by ramped surfaces  142  that are positioned on each side of the longitudinal slot  140 . The proximal portion of the anvil body  130  includes side flanges  144  that define openings  146 . Each of the openings  146  receives a pivot member  148  ( FIG. 3 ) to pivotably couple the anvil  102  to the channel member  108  of the cartridge assembly  104 . 
     The stapling device  10  ( FIG. 1 ) includes a drive assembly including a drive screw  150  ( FIG. 13 ) and the clamp member  152  ( FIG. 4 ). As known in the art, the drive screw  150  is axially fixed but rotatably supported within the cartridge assembly  104 . 
       FIGS. 4 and 6  illustrate the clamp member  152  which includes a body  154  having a first beam  156 , a second beam  158 , and a central portion  160  that interconnects the first beam  156  and the second beam  158 . The central portion  160  includes a vertical strut  162  and a hub  164 . The vertical strut  162  defines a distal stop surface  172  and has a first end that is secured to the first beam  156  and a second end that is secured to a first side of the hub  164 . The hub  164  has a second side that is connected to the second beam  158  and defines a threaded through bore  166  that receives the drive screw  150  ( FIG. 13 ). When the drive screw  150  is rotated within the cartridge assembly  104 , the clamp member  152  is driven longitudinally along the drive screw  150  within the staple cartridge  106  between retracted and advanced positions. 
     The first beam  156  is received within the channel  138  ( FIG. 8 ) defined within the anvil body  130  of the anvil  102 . When the clamp member  152  moves from its retracted position towards its advanced position, the first beam  156  of the clamp member  152  engages the ramped surfaces  142  of the anvil body  130  to pivot the anvil  102  in relation to the cartridge assembly  104  from the open position to the clamped position. The first beam  156  of the clamp member  152  includes a distally extending finger  156   a  that has a downwardly extending projection  170  that slides along the longitudinal slot  140  ( FIG. 7 ) of the anvil  102  to push tissue from within the longitudinal slot  140 . 
     The second beam  158  is positioned to move along an outer surface  108   a  ( FIG. 3 ) of the channel member  108  ( FIG. 11 ). In aspects of the disclosure, the outer surface  108   a  of the channel member  108  defines a groove (not shown) that receives the second beam  158  to guide the second beam  158  along the channel member  108 . Engagement of the first and second beams  156  and  158  with the anvil  102  and the cartridge assembly  104 , respectively, sets a maximum tissue gap between the staple forming surface  136  of the anvil  102  and the staple cartridge  106  ( FIG. 2 ) as the clamp member  152  moves through the tool assembly  100 . 
     When the staple cartridge  106  is received within the channel member  108  of the cartridge assembly  104 , the clamp member  152  is positioned proximally of and adjacent to the actuation sled  112 . In this position, the cutting member  124  of the knife  120  is positioned adjacent to the distal stop surface  172  ( FIG. 6 ) of the vertical strut  162  of the clamp member  152 . 
       FIGS. 7-11  illustrate a lock mechanism  180  of the tool assembly  100  which includes a lock member  182 , a biasing member  184 , and a pin  186 . The lock mechanism  180  is supported on the anvil body  130  of the anvil  102  to form an anvil assembly. The lock member  182  includes a circular hub portion  188 , an arm  190  that extends proximally from the hub portion  188 , an abutment member  192 , and a biasing member seat  194 . The lock member  182  is received within a recess  196  ( FIG. 8 ) defined in the anvil body  130 . The recess  196  in the anvil body  130  has a distal portion  196   a  that is cylindrical and receives the circular hub portion  188  of the lock member  182  to facilitate rotation of the lock member  182  within the recess  196 . The anvil body  130  also defines a transverse through bore  198  ( FIG. 8 ) and a groove  200 . The through bore  198  intersects the recess  196 . The pin  186  is received within the through bore  198  and engages a flat  188   a  ( FIG. 9 ) on the distal portion of the circular hub portion  188  of the lock member  182  ( FIG. 11 ) to retain a distal end of the lock member  182  within the recess  196  of the anvil body  130 . The anvil body  130  also includes an overhang  189  ( FIG. 7 ) that extends over the proximal portion of the lock member  182  to retain the proximal end of the lock member  182  within the recess  196  of the anvil body  130 . 
     In an alternate version of the disclosure shown in  FIG. 11A , the pin  186  is replaced by a second overhang  189 ′ that is formed on the anvil body  130 ′. The second overhang  189 ′ also retains the lock member  182 ′ within the recess  196 ′ of the anvil body  130 ′. 
     The lock member  182  includes a transverse blind bore  202  ( FIG. 9 ) that is aligned with the biasing member seat  192 . The biasing member  184  of the lock mechanism  180  is received within the groove  200  ( FIG. 8 ) in the anvil body  130  and extends into the blind bore  202  and into engagement with the biasing member seat  192  of the lock member  182  to urge the lock member  182  towards a locked position described in further detail below. In aspects of the disclosure, the biasing member  184  includes a coil spring although the use of a variety of different biasing members is envisioned. 
     The abutment member  192  of the lock member  182  extends upwardly from the arm  190  of the lock member  182  and from the anvil body  130  (as viewed in  FIG. 7 ) towards the cartridge assembly  104  ( FIG. 3 ). The abutment member  192  is positioned adjacent the longitudinal slot  140  ( FIG. 8 ) of the anvil  102  and includes a tapered or angled engagement surface  206  and an abutment surface  208 . The lock member  182  is rotatable about an axis “Z” ( FIG. 12 ) defined by the circular hub portion  188  from an unlocked position ( FIG. 14 ) to a locked position ( FIG. 16 ). In the locked position, the abutment member  192  extends at least partially across the longitudinal slot  140  of the anvil  102 . 
       FIGS. 12-14  illustrate the tool assembly  100  ( FIG. 3 ) in the clamped position with the lock mechanism  180  in the unlocked position. When a new staple cartridge  106  ( FIG. 2 ), i.e., unfired, is positioned within the channel member  108  of the cartridge assembly  104  and the tool assembly  100  is moved to the clamped position, the staple forming surface  136  ( FIG. 8 ) of the anvil  102  moves into juxtaposed alignment with the staple cartridge  106 . As the anvil  102  pivots in relation to the staple cartridge  106  ( FIG. 2 ), the angled engagement surface  206  ( FIG. 10 ) of the abutment  192  of the lock member  182  engages the cutting member  124  of the knife  120 . This engagement rotates the lock member  182  of the lock mechanism  180  about the pivot axis “Z” ( FIG. 12 ) in the direction of arrow “A” in  FIG. 12  against the urging of the biasing member  184  from the locked position ( FIG. 16 ) to the unlocked position ( FIG. 13 ). In the unlocked position, the lock member  182  is engaged with the cutting member  124  of the knife  120  to retain the abutment surface  208  of the abutment member  192  in a position outwardly of the distal stop surface  172  of the clamp member  152 . In this position, the stapling device  10  ( FIG. 1 ) can be fired. 
       FIGS. 15 and 16  illustrate the tool assembly  100  in the clamped position and the lock mechanism  180  in the locked position. When the stapling device  10  ( FIG. 1 ) is fired, the clamp member  152  is advanced through the tool assembly  100  from a retracted position to an advanced position. As the clamp member  152  moves through the tool assembly  100 , the clamp member  152  abuts and advances the actuation sled  112  and the knife  120  (which is supported on the actuation sled  112 ) through the staple cartridge  106 . Since the actuation sled  112  is only in abutting relationship with the clamp member  152 , when the clamp member  152  is moved from the advanced position back to the retracted position, the actuation sled  112  ( FIG. 12 ) and the knife  120  remain in the distal end of the staple cartridge  106 . As such, after the stapling device  10  ( FIG. 1 ) is fired and the clamp member  152  is returned to the retracted position, the cutting member  124  of the knife  120  is no longer positioned to obstruct movement of the lock member  182  of the lock mechanism  180  from the unlocked position to the locked position. Thus, the lock member  182  is moved by the biasing member  184  from the unlocked position ( FIG. 14 ) to the locked position ( FIG. 16 ) in which the abutment surface  208  of the lock member  182  is positioned in alignment with the distal stop surface  172  of the clamp member  152  to prevent distal movement (or readvancement) of the clamp member  152  within the staple cartridge  106 . 
       FIGS. 17 and 18  illustrate an alternative version of the lock mechanism shown generally as lock mechanism  280 . The lock mechanism  280  is substantially like lock mechanism  180  ( FIG. 8 ) except that the pin  186  ( FIG. 16 ) is not included in the lock assembly  280  and the circular hub portion  188  of the lock member  182  ( FIG. 9 ) is replaced with a pivot member  288  ( FIG. 18 ). In this version of the lock mechanism  280 , the distal portion of the lock member  282  defines a through bore  290  and the pivot member  288  includes a protrusion  292  that is fixedly received within the through bore  290 . In aspects of the disclosure, the through bore  290  and the protrusion  292  are not circular to prevent rotation of the protrusion  292  within the through bore  290 . In some aspects of the disclosure, the through bore  290  of the lock member  282  and the protrusion  292  of the pivot member  288  have oval configurations. The pivot member  288  also includes a head portion  294  ( FIG. 18 ) and a circular hub portion  296 . The circular hub portion  296  of the pivot member  288  is rotatably received within the distal portion  196   a  of the recess  196  in the anvil body  130 . The recess  196  extends through the anvil body  130  such that the circular hub portion  296  is received within the distal portion  196   a  of the recess  196 . The head portion  294  of the pivot member  288  engages the outer surface of the anvil body  130  to prevent the pivot member  288  from passing through the anvil body  130 . 
     The lock mechanism  280  also includes a biasing member  284  that is like biasing member  184  of lock mechanism  180  ( FIG. 14 ) to urge the lock member  282  towards the locked position. The lock mechanism  280  functions in a substantially similar manner to the lock mechanism  180  and will not be described in further detail herein. 
     In aspects of the disclosure, the lock members  182 ,  282  of the lock mechanisms  180 ,  280  can be molded from a suitable material, e.g., plastic. In an alternate version of the lock assembly, as shown in  FIG. 19 , the lock member shown generally as lock member  382  can be stamped from sheet metal. 
     Each of the lock mechanisms disclosed is supported on the anvil of the tool assembly of the stapling device. By positioning the lock mechanism on the anvil, the lock mechanism remains in a locked position until the tool assembly is moved to the clamped position. Although each of the lock mechanisms is shown for use with a stapling device having a staple cartridge that includes a knife, it is envisioned that the lock mechanisms are also suitable for use with stapling devices that do not include a knife. In such devices, the lock members of the lock mechanisms would engage the actuation sled of the staple cartridge to retain the lock mechanism in the unlocked position prior to actuation of the stapling device. 
     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 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.