Patent Description:
The present disclosure is directed to surgical stapling devices, and more particularly, to surgical stapling devices with tool assemblies that are supported on the stapling device for articulation.

Surgical stapling devices configured for endoscopic or laparoscopic use include an elongate body having a proximal portion and a distal portion, and a tool assembly supported on the distal portion of the elongate body. Typically, the tool assembly is supported by a pivot member that facilitates articulation of the tool assembly in relation to the elongate body. In some stapling devices, the tool assembly is limited to about <NUM> degrees of articulation about the pivot member in one or both directions.

Known stapling devices include an articulation mechanism that extends through a body of the stapling device and has a distal end that is coupled to the tool assembly. Typically, the articulation mechanism includes one or more articulation links that are movable along a longitudinal axis of the body of the stapling device to pivot the tool assembly about an axis transverse to the longitudinal axis.

In known stapling devices, the tool assembly is unstable when the tool assembly is in a non-articulated position, i.e., the position in which a longitudinal axis of the tool assembly is aligned with a longitudinal axis the elongate body. As such, the tool assembly becomes misaligned with the longitudinal axis of the body as the tool assembly is moved within a body cavity. <CIT> discloses a surgical stapling apparatus configured for use with disposable loading units. In various embodiments, the surgical stapling apparatus includes a retraction system that interfaces with an actuation shaft that is movably supported within a handle housing. The actuation shaft is configured to move axially within the handle housing from a fully retracted position to a fully fired position in response to manipulation of a movable handle operably mounted to the handle housing. The retraction system serves to automatically retract the actuation shaft to the fully retracted position when the actuation shaft has moved to the fully fired position.

A continuing need exists in the art for a stapling device that includes a tool assembly that can be articulated over a wider range of angles and is stable in all positions of articulation including a non-articulated position.

The herein claimed invention relates to a surgical stapling device according to claim <NUM>. Optional features are defined in the dependent claims.

One aspect of the disclosure is directed to a surgical stapling device including a body portion, a mounting assembly, a drive assembly, an articulation assembly, and a gate assembly. The housing includes a proximal portion and a distal portion. The mounting assembly is pivotably supported on the distal portion of the housing about a pivot axis and movable between a non-articulated position and an articulated position. The drive assembly includes a flexible body having a working end. The drive assembly is movable within the housing from a retracted position to an advanced position. The articulation assembly includes an active articulation link having a proximal portion and a distal portion that is coupled to the mounting assembly. The active articulation link is movable between a retracted position and an advanced position to pivot the mounting assembly about the pivot axis. The gate assembly defines a channel that receives the flexible body of the drive assembly, wherein the active articulation link is positioned to engage the gate assembly when the active articulation link moves between its retracted and advanced positions to move the gate assembly to a position to increase the bending radius of the flexible body of the drive assembly.

In embodiments, the gate assembly is pivotably supported within the housing.

In some embodiments, the gate assembly includes an upper gate and a lower gate.

In certain embodiments, each of the upper and lower gates includes an elongate body and a U-shaped member supported on a distal portion, wherein the U-shaped members of the upper and lower gates define the channel.

In embodiments, the elongate body of each of the upper and lower gates includes a pivot member that pivotably connects the upper and lower gates within the housing.

In some embodiments, each of the U-shaped members of the upper and lower gates includes an engagement member, wherein the active articulation link is positioned to engage one of the engagement members of the upper or lower gates.

In certain embodiments, the articulation link includes a passive articulation link having a distal portion coupled to the mounting assembly such that pivotal movement of the mounting assembly about the pivot axis causes movement of the passive articulation link between retracted and advanced positions within the housing.

In embodiments, a blowout plate is supported on each side of the elongate body of the drive assembly. Each of the blowout plates includes a distal end supported on the mounting assembly at a position distally of the pivot axis and a proximal end supported within the housing proximally of the pivot axis.

In some embodiments, a stabilization mechanism is engaged with the active and passive articulation links and is configured to urge the mounting assembly to the non-articulated position.

In embodiments, a tool assembly is supported on the mounting assembly.

In some embodiments, the tool assembly includes a cartridge assembly and an anvil assembly.

In certain embodiments, the tool assembly is configured to receive the working end of the device assembly.

In embodiments, the distal portion of the active articulation link includes a hook and the mounting assembly includes a finger, wherein the hook is positioned to engage the finger when the active articulation link is moved towards the advanced position to assist in articulation of the mounting assembly.

In some embodiments, the active articulation link includes a first active articulation link and a second active articulation link that is pivotably coupled to the first active articulation link.

In certain embodiments, the distal portions of each of the active articulation link and the passive articulation link include a hook and the mounting assembly includes fingers, wherein the hooks are positioned to engage a respective one of the fingers when the respective active and passive articulation links are moved towards the advanced position to assist in articulation of the mounting assembly.

In embodiments, the active articulation link includes a first active articulation link and a second active articulation link that is pivotably coupled to the first active articulation link, and the passive articulation link includes a first passive articulation link and a second passive articulation link that is pivotably coupled to the first passive articulation link.

Various embodiments of the presently disclosed surgical stapling device are described herein below with reference to the drawings, wherein:.

The presently disclosed 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 the disclosed embodiments 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 present 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 present 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 "endoscopic" is used generally used to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through small diameter incision or cannula. Further, the term "clinician" is used generally to refer to medical personnel including doctors, nurses, and support personnel.

Referring to <FIG>, the presently surgical stapling device is shown generally as stapling device <NUM> and includes a handle assembly <NUM>, an adapter assembly <NUM>, and a tool assembly <NUM>. In embodiments, the tool assembly <NUM> forms part of a reload assembly <NUM> that includes the tool assembly <NUM> and a body portion <NUM> that has a proximal portion <NUM> and a distal portion <NUM>. The adapter assembly <NUM> and the body portion <NUM> of the reload <NUM> define a longitudinal axis "X" (<FIG>). The proximal portion <NUM> of the body portion <NUM> of the reload <NUM> is adapted to be coupled to a distal portion <NUM> of the adapter assembly <NUM> and the distal portion of the body portion <NUM> is pivotally coupled to the tool assembly <NUM> about a pivot axis "Y" (<FIG>) that is substantially perpendicular to the longitudinal axis "X". The tool assembly <NUM> is pivotal between a non-articulated position (<FIG>) in which the tool assembly <NUM> is aligned with the longitudinal axis "X" and articulated positions in which the tool assembly <NUM> defines an acute angle with the longitudinal axis "X". It is envisioned that the tool assembly <NUM> may be connected directly to the distal portion <NUM> of the adapter assembly <NUM> and need not form part of a reload assembly <NUM>.

In embodiments, the handle assembly <NUM> is powered and includes a stationary handle <NUM> and actuation buttons <NUM> that can be actuated to control various functions of the stapling device <NUM> including approximation and firing of the tool assembly <NUM>. <CIT> ("the '<NUM> Patent") discloses a surgical stapling device having a powered handle assembly, an adapter assembly, and a tool assembly that is releasably coupled to the adapter assembly. Alternately, the handle assembly <NUM> can be manually actuated such as described in <CIT> ("the '<NUM> Patent").

Referring to <FIG>, the tool assembly <NUM> includes an anvil assembly <NUM> and a cartridge assembly <NUM>. In embodiments, the cartridge assembly <NUM> includes a staple cartridge 42a and channel 42b and is pivotally coupled to the anvil assembly <NUM> between an open position and a clamped position. Alternatively, it is envisioned that the cartridge assembly <NUM> can be stationary and the anvil assembly <NUM> can be movable between the open and clamped positions such as described in the '<NUM> Patent.

Referring to <FIG>, the body portion <NUM> of the reload assembly <NUM> (<FIG>) includes an outer casing <NUM>, a first housing half-section <NUM>, a second housing half-section <NUM>, a mounting assembly <NUM>, first and second active articulation links <NUM>, <NUM>, first and second passive articulation links <NUM>, <NUM>, a drive assembly <NUM>, an articulation stabilization mechanism <NUM>, and a gate assembly <NUM>. The drive assembly <NUM> of the reload assembly <NUM> includes a flexible body <NUM> having a working end <NUM>. The working end <NUM> is movable through the tool assembly <NUM> to actuate the tool assembly <NUM> as is known in the art. For a more detailed description of the structure and operation of the drive assembly <NUM>, see the '<NUM> Patent. The first and second housing half-sections <NUM>, <NUM>, respectively, are secured together to define a housing <NUM> that supports the articulation links and the articulation stabilization mechanism <NUM> as described in further detail below.

The mounting assembly <NUM> (<FIG>) includes a first mounting portion <NUM>, a second mounting portion <NUM>, a first coupling member <NUM>, and a second coupling member <NUM>. The first mounting portion <NUM> defines a longitudinal slot 72a and includes a pivot member <NUM> and internal fingers <NUM>. The internal fingers <NUM> are positioned to engage the articulation links <NUM> and <NUM> during articulation of the tool assembly <NUM> as discussed in further detail below. The first coupling member <NUM> has a first end that defines an opening 76a that receives the pivot member <NUM> and a second end 76b that is received within a recess <NUM> defined in a distal end of the first housing half-section <NUM> of the reload <NUM> such that the first coupling member <NUM> pivotably secures the tool assembly <NUM> to the first housing half-section <NUM>. The pivot member <NUM> is also received in an opening 40a (<FIG>) defined in a proximal end of the anvil assembly <NUM> to pivotally couple the anvil assembly <NUM> to the first mounting portion <NUM> of the mounting assembly <NUM>.

The second mounting portion <NUM> also includes a pivot member <NUM> (<FIG>). The second coupling member <NUM> has a first end defining an opening 74a that receives the pivot member <NUM> of the second mounting portion <NUM> and a second end that is received within a recess <NUM> defined within the second housing half-section <NUM> to pivotally secure the second mounting portion <NUM> to the second housing half-section <NUM> of the body portion <NUM> of the reload assembly <NUM>. The outer casing <NUM> of the proximal portion <NUM> of the reload <NUM> is positioned about the first and second housing half-sections <NUM>, <NUM> to prevent separation of the first and second housing half-sections <NUM>, <NUM> from one another and to prevent the second ends of the first and second coupling members <NUM>, <NUM> from moving from within the recesses <NUM>, <NUM>, respectively.

The second mounting portion <NUM> includes distal extensions <NUM> that define a slot <NUM> that is aligned with the slot 72a in the first mounting portion <NUM>. The distal extensions <NUM> are received in a proximal end of the anvil assembly <NUM> (<FIG>) and define openings <NUM>. The proximal ends of the anvil assembly <NUM> and the channel 42b of the cartridge assembly <NUM> also define openings <NUM> that are aligned with the openings <NUM> in the second mounting portion <NUM> of the mounting assembly <NUM>. The openings <NUM> and <NUM> receive pivot members (not shown) to secure the anvil assembly <NUM> to the second mounting portion <NUM> and to pivotably secure the cartridge assembly <NUM> to the anvil assembly <NUM> about the pivot axis "Y" (<FIG>).

Referring to <FIG>, the first and second mounting portions <NUM>, <NUM>, respectively, are secured together using pins or rivets to fixedly secure the tool assembly <NUM> to the mounting assembly <NUM>. For a more detailed description of the interconnection between the mounting assembly <NUM> and the tool assembly <NUM>, see the '<NUM> Patent.

Referring to <FIG>, the first and second active articulation links <NUM>, <NUM>, respectively, are supported between the first and second housing half-sections <NUM>, <NUM> on opposite sides of the housing <NUM> of the body portion <NUM>. The first active articulation link <NUM> is elongate and includes a proximal portion <NUM> and a distal portion <NUM>. The proximal portion <NUM> is adapted to engage an articulation drive mechanism (not shown) located within the adapter assembly <NUM> to translate motion of the drive mechanism into longitudinal movement of the articulation link <NUM>. In embodiments, the proximal portion <NUM> may include a transverse extension <NUM> that is positioned to engage the articulation drive mechanism (not shown) of the adapter assembly <NUM> as known in the art. Alternately, it is envisioned that the active articulation link <NUM> can engage the drive mechanism (not shown) of the adapter assembly <NUM> using a variety of different configurations or coupling devices. The distal portion <NUM> of the articulation link <NUM> includes an inner cam surface <NUM>, a hook <NUM>, and an opening <NUM>. The cam surface <NUM> forms the inner surface of the hook <NUM> and is positioned to support one side of the drive assembly <NUM> as described in further detail below. The cam surface <NUM> defines a curved surface that extends towards the longitudinal axis "X" in a distal direction.

The function of the hook <NUM> will be described in further detail below. The opening <NUM> receives a pivot member <NUM> that is supported on the second active articulation link <NUM> to pivotally couple the second active articulation link <NUM> to the distal portion <NUM> of the first active articulation link <NUM>.

The second active articulation link <NUM> also includes a distal portion that defines an opening <NUM>. The opening <NUM> receives a pivot member <NUM> (<FIG>) that is supported on a first side of the mounting assembly <NUM> at a position transversely offset from the pivot axis "Y" (<FIG>) to pivotally secure the second active articulation link <NUM> to the mounting assembly <NUM>. Although not shown, the first active articulation link <NUM> is confined to linear movement within the housing <NUM> of the body portion <NUM> of the reload assembly <NUM>. Pivotally coupling the second articulation link <NUM> between the first articulation link <NUM> and the mounting assembly <NUM> increases the range of articulation of the tool assembly <NUM> in relation to the adapter assembly <NUM> that is possible. When the first active articulation link <NUM> is moved longitudinally within the body portion <NUM> of the reload <NUM>, the second active articulation link <NUM> is advanced and pivoted about the pivot member <NUM> to cause pivotal movement of the tool assembly <NUM> about the axis "Y" (<FIG>). It is noted that the length of the second active articulation link <NUM> is substantially shorter than the length of the first active articulation link <NUM> such that the links <NUM> and <NUM> do not protrude outwardly of the mounting assembly <NUM> beyond a predetermined distance when the mounting assembly <NUM> and tool assembly <NUM> are articulated.

The first active articulation link <NUM> also defines a bushing engagement surface <NUM>. In embodiments, the bushing engagement surface <NUM> is positioned between the proximal and distal portions <NUM>, <NUM> and is positioned to interact with the stabilization mechanism <NUM> (<FIG>) to provide stability to the tool assembly <NUM> in the non-articulated position of the tool assembly as described in detail below.

The first passive articulation link <NUM> includes an elongate body having a proximal portion <NUM> and a distal portion <NUM>. The proximal portion <NUM> includes a bushing engagement surface <NUM> that is positioned to interact with the stabilization mechanism <NUM> (<FIG>) to provide stability to the tool assembly <NUM> in the non-articulated position of the tool assembly <NUM> as described in detail below. The distal portion <NUM> of the articulation link <NUM> includes an inner cam surface <NUM>, a hook <NUM>, and an opening <NUM>. The cam surface <NUM> forms the inner surface of the hook <NUM> and is positioned to engage one side of the drive assembly <NUM> as described in further detail below. The cam surface <NUM> defines a curved surface that extends towards the longitudinal axis "X" in a distal direction. The function of the hook <NUM> will be described in further detail below. The opening <NUM> receives a pivot member <NUM> that is supported on the second passive articulation link <NUM> to pivotally couple the second passive articulation link <NUM> to the distal portion <NUM> of the first passive articulation link <NUM>.

The second passive articulation link <NUM> also includes a distal portion that defines an opening <NUM>. The opening <NUM> receives a pivot member <NUM> that is supported on a second side of the mounting assembly <NUM> to pivotally secure the second passive articulation link <NUM> to the mounting assembly <NUM> at a position transversely offset from the pivot axis "Y" (<FIG>). Although not shown, the first passive articulation link <NUM> is confined to linear movement within the housing <NUM> of the body portion <NUM> of the reload assembly <NUM>. As described above in regard to second active articulation link <NUM>, pivotally coupling the second passive articulation link <NUM> between the first passive articulation link <NUM> and the mounting assembly <NUM> increases the range of articulation of the tool assembly <NUM> in relation to the adapter assembly <NUM>. As discussed above in regard to the second active articulation link <NUM>, the length of the second passive link <NUM> is substantially shorter than the length of the first passive articulation link <NUM> such that the links <NUM> and <NUM> do not protrude outwardly of the mounting assembly <NUM> beyond a predetermined distance.

Referring also to <FIG>, the articulation stabilization system <NUM> includes a biasing mechanism <NUM> including a slide member <NUM> and a plurality of springs <NUM>. In embodiments, the slide member <NUM> is substantially annular and includes a first half-section <NUM> and a second half-section <NUM>. The slide member <NUM> is slidably positioned within a recess <NUM> defined in an outer surface of the housing <NUM> of the body portion <NUM> of the reload assembly <NUM>. The slide member <NUM> includes distally extending spring mounting tabs <NUM>, a first proximally extending bushing <NUM>, and a second proximally extending bushing <NUM>. In embodiments, each of the half-sections <NUM>, <NUM> of the slide member <NUM> includes respective side wall recesses <NUM> and side wall extensions <NUM> that mesh to form the annular slide member <NUM>.

In embodiments, the springs <NUM> are coil springs that have a proximal portion that is received about the spring mounting tabs <NUM> of the slide member <NUM>. Each of the springs <NUM> is positioned within a respective pocket <NUM> defined in the housing <NUM> to urge the slide member <NUM> distally about the housing <NUM>. The first bushing <NUM> of the slide member <NUM> is received within the notch <NUM> of the first active articulation link <NUM> to urge the articulation link <NUM> proximally to a position in which the tool assembly <NUM> is in the non-articulated position. When the articulation link <NUM> is positioned such that the tool assembly <NUM> is in the non-articulated position, the springs <NUM> are in an unbiased state with the bushing <NUM> positioned within the notch <NUM> and engaged with the articulation link <NUM>. In addition, bushing <NUM> is positioned within the surface <NUM> in engagement with the first passive articulation link <NUM> to urge the articulation link <NUM> proximally to a position in which the tool assembly <NUM> is also in the non-articulated position. When the articulation link <NUM> is positioned such that the tool assembly <NUM> is in the non-articulated position, the springs <NUM> are in an unbiased state with the bushing <NUM> engaged positioned within the surface <NUM> of the articulation link <NUM>.

For a more detailed description of the presently disclosed stabilization system <NUM>, see <CIT>.

Referring also to <FIG>, the gate assembly <NUM> includes an upper gate <NUM> and a lower gate <NUM>. Each of the upper and lower gates <NUM>, <NUM>, respectively, includes an elongate body <NUM> and a U-shaped member <NUM>. When the upper and lower gates <NUM>, <NUM> are assembled, the gates <NUM>, <NUM> define a channel <NUM>. The channel <NUM> is dimensioned to receive and allow passage of the flexible body <NUM> of the drive assembly <NUM> as the drive assembly <NUM> is moved between retracted and advanced positions to approximate and fire staples from the stapling device <NUM> as is known in the art.

The elongate body <NUM> of each of the gates <NUM>, <NUM> includes a pivot member <NUM> that is pivotally coupled to an inner wall of the housing <NUM> of the body portion <NUM> of the reload assembly <NUM> to axially fix the gates <NUM>, <NUM> within the housing <NUM> while permitting pivotal movement of the gates <NUM>, <NUM> within the housing <NUM>. Each of the U-shaped members <NUM> of the gates <NUM>, <NUM> may have an engagement member <NUM> that is positioned to abut the cam surfaces <NUM>, <NUM> of the articulation links <NUM>, <NUM>, respectively, as described in further detail below. In use, the gates <NUM>, <NUM> increase a bending radius of the flexible body <NUM> of the drive assembly <NUM> when the tool assembly <NUM> is in an articulated position in relation to the adapter assembly <NUM>.

Referring again to <FIG> and <FIG>, the reload assembly <NUM> also includes blow out plates <NUM>. The blowout plates <NUM> are positioned on opposite sides of the flexible body <NUM> of the drive assembly <NUM> and extend from a position distal of the pivot axis "Y" (<FIG>) to a position proximal of the pivot axis "Y". In embodiments, distal ends of the blow out plates <NUM> are secured within a slot <NUM> (<FIG>) in the mounting assembly <NUM>. In some embodiments, a proximal end of the blowout plates <NUM> includes a transverse portion <NUM> that is received within a recess <NUM> (<FIG>) within the housing <NUM> of the body portion <NUM> to allow the proximal end of the blow out plates <NUM> to slide within the housing <NUM>. The sliding movement allows the blowout plates <NUM> to adjust accordingly when the radius of curvature changes as the tool assembly <NUM> is articulated about the pivot axis "Y". The blowout plates <NUM> are positioned to obstruct outward bulging of the flexible body <NUM> of the drive assembly <NUM> during approximation and firing of the stapling device <NUM>. See the '<NUM> patent for a more detailed description of the blowout plates <NUM>.

Referring to <FIG>, when the tool assembly <NUM> of the reload <NUM> is in a non-articulated position, the flexible body <NUM> of the drive assembly <NUM> extends along the longitudinal axis "X" of the body portion <NUM> of the reload <NUM> between the blowout plates <NUM> and through the channel <NUM> of the gate assembly <NUM>. In addition, the articulation links <NUM> and <NUM> are urged to neutral positions by the stabilization mechanism <NUM>. In their neutral positions, the cam surface <NUM>, <NUM> of the articulation links <NUM>, <NUM> are positioned in engagement with outer walls of the blowout plates <NUM> and the gates assembly <NUM> is positioned such that the channel <NUM> defines by the gate assembly <NUM> is aligned with the longitudinal axis "X". It is noted that the engagement members <NUM> of the gates <NUM>, <NUM> of the gate assembly <NUM> are positioned towards a proximal end of the cam surfaces106, <NUM>. As discussed above, the cam surfaces <NUM>, <NUM> define curved surfaces that extend towards the longitudinal axis "X" in a distal direction.

Referring to <FIG>, when the active articulation link <NUM> is advanced in the direction indicated by arrows "A" in <FIG> by actuating the drive mechanism in the adapter assembly <NUM> (<FIG>), the first active articulation link <NUM> advances the second active articulation link <NUM> to pivot the mounting assembly <NUM> and the tool assembly <NUM> about the pivot axis "Y" (<FIG>). As the tool assembly <NUM> pivots about the pivot axis "Y", the second passive articulation link <NUM> is moved proximally by the pivot member <NUM> of the mounting assembly <NUM>. As the second passive articulation link <NUM> is moved proximally, the first passive articulation link <NUM> which is pivotally coupled to the second passive articulation link <NUM> also moves proximally in the direction indicated by arrow "B" in <FIG>.

When the tool assembly <NUM> is pivoted about the pivot axis "Y", the flexible body <NUM> of the drive assembly <NUM> bends about the pivot axis "Y" (<FIG>). As discussed above, the gates <NUM>, <NUM> (<FIG>) of the gate assembly <NUM> define a channel <NUM> that receives the flexible body <NUM> of the drive assembly <NUM>. When the first passive articulation link <NUM> is retracted in the direction indicated by arrow "B" in <FIG>, the cam surface <NUM> of the first passive articulation link <NUM> engages the engagement surface <NUM> of the gate assembly <NUM> to pivot the gate assembly <NUM> about the pivot members <NUM> in the direction indicated by arrow "C" in <FIG>. As the gate assembly <NUM> pivots about the pivot members <NUM>, the gate assembly <NUM> engages the flexible body <NUM> of the drive assembly <NUM> to urge the flexible body <NUM> towards the first active articulation link <NUM>. This increases the bending radius of the flexible body <NUM> of the drive assembly <NUM> by relocating the position of the flexible body <NUM> in a direction opposite to the direction of articulation of the tool assembly <NUM>. As can be seen in <FIG>, the cam surface <NUM> of the articulation link <NUM> provides added support to the outer surface of the flexible body <NUM> of the drive assembly <NUM> to prevent buckling of the flexible body <NUM> when the tool assembly <NUM> is articulated.

As shown in <FIG>, as the active articulation link <NUM> moves distally towards the mounting assembly <NUM>, the hook <NUM> on the distal portion of the first active articulation link <NUM> engages the internal finger <NUM> of the mounting assembly <NUM> to urge the mounting assembly <NUM> in the direction of articulation.

When the first active articulation link <NUM> moves proximally as shown in <FIG>, the bushing engagement surface <NUM> of the first active articulation link <NUM> engages and urges the slide member <NUM> distally in the direction indicated by arrow "K" against the urging of the springs <NUM> to compress the springs <NUM>. As described in detail in the '<NUM> application, the spring force of the springs <NUM> urges the slide member <NUM> proximally to urge the first active articulation link <NUM> towards a position in which the mounting assembly <NUM> is in a non-articulated position.

Referring to <FIG>, when the active articulation link <NUM> is retracted in the direction indicated by arrows "D" by actuating the drive mechanism in the adapter assembly <NUM> (<FIG>), the first active articulation link <NUM> retracts the second active articulation link <NUM> to pivot the tool assembly <NUM> in an opposite direction about the pivot axis "Y" (<FIG>). As the tool assembly <NUM> pivots about the pivot axis "Y" (<FIG>), the second passive articulation link <NUM> is moved distally and pivoted about the pivot member <NUM> of the mounting assembly <NUM>. As the second passive articulation link <NUM> is moved distally, the first passive articulation link <NUM> which is pivotally coupled to the second passive articulation link <NUM> also moves distally in the direction indicated by arrow "E".

When the tool assembly <NUM> is pivoted about the pivot axis "Y", the flexible body <NUM> of the drive assembly <NUM> bends about the pivot axis "Y". As discussed above, the gates <NUM>, <NUM> (<FIG>) of the gate assembly <NUM> define a channel <NUM> that receives the flexible body <NUM> of the drive assembly. When the first active articulation link <NUM> is retracted in the direction indicated by arrow "D" in <FIG>, the cam surface <NUM> of the first active articulation link <NUM> engages the engagement surface <NUM> of the gate assembly <NUM> to pivot the gate assembly <NUM> about the pivot members <NUM> in the direction indicated by arrow "F". As the gate assembly <NUM> pivots about the pivot members <NUM>, the gate assembly <NUM> engages the flexible body <NUM> of the drive assembly <NUM> to urge the flexible body <NUM> towards the first passive articulation link <NUM>. This increases the bending radius of the flexible body <NUM> of the drive assembly <NUM> by relocating the position of the flexible body <NUM> in a direction opposite to the direction of articulation of the tool assembly <NUM>. Although not shown in <FIG>, the cam surface <NUM> of the first passive articulation link <NUM> supports the outer surface of the blowout plate <NUM> to provide added support for the flexible body <NUM> of the drive assembly <NUM> to prevent buckling of the flexible body <NUM> when the tool assembly <NUM> is articulated.

As the first passive articulation link <NUM> moves distally towards the mounting assembly <NUM>, the hook <NUM> on the distal portion of the first passive articulation link <NUM> engages the internal finger <NUM> of the mounting assembly <NUM> to urge the mounting assembly <NUM> in the direction of articulation.

Claim 1:
A surgical stapling device (<NUM>) comprising:
a body portion (<NUM>) including a housing (<NUM>), a mounting assembly (<NUM>), a drive assembly (<NUM>), an articulation assembly, and a gate assembly (<NUM>), the housing (<NUM>) including a proximal portion and a distal portion, the mounting assembly (<NUM>) being pivotably supported on the distal portion of the housing (<NUM>) about a pivot axis (Y) between a non-articulated position and an articulated position, the drive assembly (<NUM>) including a flexible body (<NUM>) having a working end (<NUM>), the drive assembly (<NUM>) being movable within the housing (<NUM>) from a retracted position to an advanced position, the articulation assembly including an active articulation link (<NUM>) and a passive articulation link (<NUM>), the active articulation link (<NUM>) having a proximal portion (<NUM>) and a distal portion (<NUM>), the distal portion (<NUM>) of the active articulation link (<NUM>) being coupled to the mounting assembly (<NUM>) and movable between retracted and advanced positions to pivot the mounting assembly (<NUM>) about the pivot axis (Y), the passive articulation link (<NUM>) having a distal portion (<NUM>) coupled to the mounting assembly (<NUM>) such that pivotal movement of the mounting assembly (<NUM>) about the pivot axis (Y) causes movement of the passive articulation link (<NUM>) between retracted and advanced positions,
the gate assembly (<NUM>) defining a channel (<NUM>), the flexible body (<NUM>) of the drive assembly (<NUM>) extending through the channel (<NUM>) of the gate assembly (<NUM>), wherein the passive articulation link (<NUM>) is positioned to engage the gate assembly (<NUM>) when the passive articulation link (<NUM>) moves between its retracted and advanced positions to move the gate assembly (<NUM>) to a position to increase a bending radius of the flexible body (<NUM>) of the drive assembly (<NUM>), wherein the gate assembly (<NUM>) is pivotably supported within the housing (<NUM>), and wherein the gate assembly (<NUM>) includes an upper gate (<NUM>) and a lower gate (<NUM>), and wherein each of the upper and lower gates (<NUM>, <NUM>) includes an elongate body (<NUM>) and a U-shaped member (<NUM>) supported on a distal portion, wherein the U-shaped members (<NUM>) of the upper and lower gates (<NUM>, <NUM>) define the channel (<NUM>).