Patent Description:
Robotic surgical systems are increasingly utilized in various different surgical procedures. Some robotic surgical systems include a console supporting a robotic arm. One or more different surgical instruments may be configured for use with the robotic surgical system and selectively mountable to the robotic arm. The robotic arm provides one or more inputs to the mounted surgical instrument to enable operation of the mounted surgical instrument.

The number, type, and configuration of inputs provided by the robotic arm of a robotic surgical system are constraints in the design of surgical instruments configured for use with the robotic surgical system. That is, in designing a surgical instrument compatible for mounting on and use with the robotic arm of a robotic surgical system, consideration should be given as to how to utilize the available inputs provided by the robotic arm to achieve the desired functionality of the surgical instrument. Background prior art is disclosed in <CIT>. Prior art previously cited under Art. <NUM>(<NUM>) EPC is <CIT>, <CIT>.

As used herein, the term "distal" refers to the portion that is being described which is further from a surgeon, while the term "proximal" refers to the portion that is being described which is closer to a surgeon. The terms "about," substantially," and the like, as utilized herein, are meant to account for manufacturing, material, environmental, use, and/or measurement tolerances and variations. Further, to the extent consistent, any of the aspects described herein may be used in conjunction with any or all of the other aspects described herein.

Provided in accordance with aspects of the present disclosure is a surgical instrument including a housing, a shaft extending from the housing, and end effector coupled to a distal portion of the shaft, and a gearbox assembly disposed within the housing. The gearbox assembly includes an articulation sub-assembly configured to articulate the end effector about a longitudinal axis defined by the shaft. The articulation sub-assembly includes a first lead screw including a gear portion, a waist portion, and an elongate threaded body portion, and a second lead screw including a gear portion and an elongate threaded body portion. A first nut is threadingly engaged with the elongate threaded body portion of the first lead screw such that rotation of the first lead screw effects longitudinal translation of the first nut. A second nut is threadingly engaged with the elongate threaded body portion of the second lead screw such that rotation of the second lead screw effects longitudinal translation of the second nut. The articulation sub-assembly further includes a middle plate including a middle plate stem extending proximally therefrom and a proximal center gear and a distal center gear coupled to the middle plate stem. Each of the proximal center gear and the distal center gear includes a proximal gear portion and a distal gear portion. The distal gear portion of the proximal center gear is meshingly engaged with the gear portion of the first lead screw. Additionally, the distal gear portion of the distal center gear is meshingly engaged with the gear portion of the second lead screw and the proximal gear portion of the distal center gear is aligned with the waist portion of the first lead screw.

In an aspect, the articulation sub-assembly includes a first input shaft and a second input shaft. The first input shaft includes a gear portion meshingly engaged with the proximal gear portion of the proximal center gear such that rotation of the first input shaft causes rotation of the proximal center gear and the first lead screw. The second input shaft includes a first input shaft including a gear portion meshingly engaged with the proximal gear portion of the proximal center gear such that rotation of the first input shaft causes rotation of the proximal center gear and the first lead screw.

In an aspect, the articulation sub-assembly includes a proximal plate aligning the first input shaft with the first lead screw.

In an aspect, the middle plate aligns the second input shaft with the second lead screw.

In an aspect, the surgical instrument includes articulation cables including respective distal ends coupled to the end effector and respective proximal ends each coupled to one of the first nut and the second nut such that longitudinal translation of the first nut and the second nut causes articulation of the end effector.

In an aspect, the surgical instrument includes a first guide bar and a second guide bar disposed within the housing. The first guide bar is operably coupled to the middle plate and the first nut and is configured to inhibit rotation of the first nut relative to the first lead screw. The second guide bar is operably coupled to the middle plate and the second nut and is configured to inhibit rotation of the second nut relative to the second lead screw.

In an aspect, the articulation sub-assembly includes a third lead screw and a third nut. The third lead screw includes a gear portion, a waist portion, and an elongate threaded body portion. The gear portion of the third lead screw is meshingly engaged with the distal gear portion of the proximal center gear and the waist portion of the third lead screw is aligned with the proximal gear portion of the distal center gear. The third nut is threadingly engaged with the elongate threaded body portion of the third lead screw such that rotation of the third lead screw effects longitudinal translation of the third nut.

In an aspect, the articulation sub-assembly includes a fourth lead screw and a fourth nut. The fourth lead screw includes a gear portion and an elongate threaded body portion. The gear portion of the fourth lead screw is meshingly engaged with the distal gear portion of the distal center gear. The fourth nut is threadingly engaged with the elongate threaded body portion of the fourth lead screw such that rotation of the fourth lead screw effects longitudinal translation of the fourth nut.

In an aspect, the surgical instrument includes a third guide bar and a fourth guide bar disposed within the housing. The third guide bar is operably coupled to the middle plate and the third nut and is configured to inhibit rotation of the third nut relative to the third lead screw. The fourth guide bar is operably coupled to the middle plate and the fourth nut and is configured to inhibit rotation of the fourth nut relative to the fourth lead screw.

In an aspect, the end effector includes a first jaw member and a second jaw member, where the first jaw member is movable relative to the second jaw member between an open position and a closed position to grasp tissue therebetween. Additionally, in an aspect, the gearbox assembly further includes a jaw drive sub-assembly operably coupled to at least one of the first jaw member or the second jaw member and configured to move the first jaw member relative to the second jaw member between the open position and the closed position.

In an aspect, the jaw drive sub-assembly includes a drive rod operably coupled to at least one of the first jaw member or the second jaw member and a spring force assembly releasably coupled to the drive rod. The spring force assembly includes a proximal hub defining an elongate hub stem, a compression spring disposed around the elongate hub stem, a distal hub disposed around a distal portion of the compression spring and movable relative to the proximal hub, and a lock plate slidingly coupled to the proximal hub and configured to releasably lock the drive rod to the proximal hub.

In an aspect, a distal portion of the elongate hub stem includes a wing extending radially outward therefrom and the distal hub defines a shelf configured to engage the wing to inhibit distal translation of the distal hub beyond the wing thereby defining a maximum distance between the proximal hub and the distal hub.

In an aspect, the jaw drive sub-assembly includes an input shaft having an elongate threaded body portion threadingly engaged with a threaded bore of the distal hub such that rotation of the input shaft causes longitudinal translation of the distal hub.

In an aspect, the proximal hub includes a retainer guide and the distal hub includes a retainer guide. Each of the retainer guide of the proximal hub and the retainer guide of the distal hub is configured to operably couple to a guide bar to inhibit rotation of the distal hub relative to the proximal hub.

In an aspect, the spring force assembly is configured to maintain a jaw force between the first jaw member and the second jaw member during articulation of the end effector.

In an aspect, a proximal portion of the drive rod includes a key and the lock plate defines a key hole configured to receive the key to releasably secure the drive rod to the proximal hub.

Also provided in accordance with aspects of the present disclosure is a gearbox assembly for use with surgical instrument including an end effector having a first jaw member and a second jaw member. The gearbox assembly includes an articulation sub-assembly configured to articulate the end effector and a jaw drive sub-assembly configured to transition the end effector between an open position and a closed position. The articulation sub-assembly includes a first lead screw including a gear portion, a waist portion, and an elongate threaded body portion and a second lead screw including a gear portion and an elongate threaded body portion. A first nut is threadingly engaged with the elongate threaded body portion of the first lead screw such that rotation of the first lead screw effects longitudinal translation of the first nut. A second nut is threadingly engaged with the elongate threaded body portion of the second lead screw such that rotation of the second lead screw effects longitudinal translation of the second nut. The articulation sub-assembly further includes a middle plate including a middle plate stem extending proximally therefrom and a proximal center gear and a distal center gear coupled to the middle plate stem. Each of the proximal center gear and the distal center gear includes a proximal gear portion and a distal gear portion. The distal gear portion of the proximal center gear is meshingly engaged with the gear portion of the first lead screw. Additionally, the distal gear portion of the distal center gear is meshingly engaged with the gear portion of the second lead screw and the proximal gear portion of the distal center gear is aligned with the waist portion of the first lead screw. Additionally, the jaw drive sub-assembly includes a drive rod operably coupled to at least one of the first jaw member or the second jaw member and a spring force assembly releasably coupled to the drive rod. The spring force assembly includes a proximal hub defining an elongate hub stem, a compression spring disposed around the elongate hub stem, a distal hub disposed around a distal portion of the compression spring and movable relative to the proximal hub, and a lock plate slidingly coupled to the proximal hub and configured to releasably lock the drive rod to the proximal hub.

In an aspect, the gearbox assembly includes a guide bar operably coupled to the articulation sub-assembly and the jaw drive sub-assembly and configured to maintain alignment therebetween.

Various aspects and features of the present disclosure are described hereinbelow with reference to the drawings wherein like numerals designate identical or corresponding elements in each of the several views.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, a surgical instrument <NUM> provided in accordance with the present disclosure generally includes a housing <NUM>, a shaft <NUM> extending distally from housing <NUM>, an end effector assembly <NUM> extending distally from shaft <NUM>, and a gearbox assembly <NUM> disposed within housing <NUM> and operably associated with end effector assembly <NUM>. Instrument <NUM> is detailed herein as an articulating electrosurgical forceps configured for use with a robotic surgical system, e.g., robotic surgical system <NUM> (<FIG>). However, the aspects and features of instrument <NUM> provided in accordance with the present disclosure, detailed below, are equally applicable for use with other suitable surgical instruments and/or in other suitable surgical systems.

With particular reference to <FIG>, housing <NUM> of instrument <NUM> includes first and second body portion 22a, 22b and a proximal face plate <NUM> that cooperate to enclose gearbox assembly <NUM> (<FIG>) therein. Proximal face plate <NUM> includes apertures defined therein through which inputs <NUM>, <NUM>, <NUM>, <NUM> (<FIG>) of gearbox assembly <NUM> extend for coupling to drivers of a robotic surgical system <NUM> (<FIG>). A pair of latch levers <NUM> (only one of which is illustrated in <FIG>) extend outwardly from opposing sides of housing <NUM> and enable releasable engagement of housing <NUM> with a robotic arm of a surgical system, e.g., robotic surgical system <NUM> (<FIG>).

Shaft <NUM> of instrument <NUM> includes a distal segment <NUM>, a proximal segment <NUM>, and an articulating section <NUM> disposed between the distal and proximal segments <NUM>, <NUM>, respectively. Articulating section <NUM> includes one or more articulating components <NUM>, e.g., links, joints, etc. A plurality of articulation cables <NUM>, e.g., four (<NUM>) articulation cables, or other suitable actuators, extend through articulating section <NUM>. More specifically, articulation cables <NUM> are operably coupled to distal segment <NUM> of shaft <NUM> at the distal ends thereof and extend proximally from distal segment <NUM> of shaft <NUM>, through articulating section <NUM> of shaft <NUM> and proximal segment <NUM> of shaft <NUM>, and into housing <NUM>, wherein articulation cables <NUM> operably couple with an articulation sub-assembly <NUM> of gearbox assembly <NUM> to enable selective articulation of distal segment <NUM> (and, thus end effector assembly <NUM>) relative to proximal segment <NUM> and housing <NUM>, e.g., about at least two axes of articulation (yaw and pitch articulation, for example).

With respect to articulation of end effector assembly <NUM> relative to proximal segment <NUM> of shaft <NUM>, actuation of articulation cables <NUM> is done in pairs. More specifically, in order to pitch end effector assembly <NUM>, the upper pair of cables <NUM> is actuated in a similar manner while the lower pair of cables <NUM> is actuated in a similar manner relative to one another but an opposite manner relative to the upper pair of cables <NUM>. With respect to yaw articulation, the right pair of cables <NUM> is actuated in a similar manner while the left pair of cables <NUM> is actuated in a similar manner relative to one another but an opposite manner relative to the right pair of cables <NUM>.

Continuing with reference to <FIG>, end effector assembly <NUM> includes first and second jaw members <NUM>, <NUM>, respectively. Each jaw member <NUM>, <NUM> includes a proximal flange portion 43a, 45a and a distal body portion 43b, 45b, respectively. Distal body portions 43b, 45b define opposed tissue-contacting surfaces <NUM>, <NUM>, respectively. Proximal flange portions 43a, 45a are pivotably coupled to one another about a pivot <NUM> and are operably coupled to one another via a cam-slot assembly <NUM> including a cam pin slidably received within cam slots defined within the proximal flange portion 43a, 45a of at least one of the jaw members <NUM>, <NUM>, respectively. Such a configuration enables pivoting of jaw member <NUM> relative to jaw member <NUM> and distal segment <NUM> of shaft <NUM> between a spaced-apart position (e.g., an open position of end effector assembly <NUM>) and an approximated position (e.g., a closed position of end effector assembly <NUM>) for grasping tissue between tissue-contacting surfaces <NUM>, <NUM>. As an alternative to this unilateral configuration, a bilateral configuration may be provided whereby both jaw members <NUM>, <NUM> are pivotable relative to one another and distal segment <NUM> of shaft <NUM>.

In aspects, longitudinally-extending knife channels <NUM> (only knife channel <NUM> of jaw member <NUM> is illustrated; the knife channel of jaw member <NUM> is similarly configured) are defined through tissue-contacting surfaces <NUM>, <NUM>, respectively, of jaw members <NUM>, <NUM>. In such aspects, a knife assembly including a knife tube (not shown) extending from housing <NUM> through shaft <NUM> to end effector assembly <NUM> and a knife blade (not shown) disposed within end effector assembly <NUM> between jaw members <NUM>, <NUM> is provided to enable cutting of tissue grasped between tissue-contacting surfaces <NUM>, <NUM> of jaw members <NUM>, <NUM>, respectively.

Referring still to <FIG>, a distal portion of a drive rod <NUM> is operably coupled to cam-slot assembly <NUM> of end effector assembly <NUM>, e.g., engaged with the cam pin thereof, such that longitudinal actuation of drive rod <NUM> pivots jaw member <NUM> relative to jaw member <NUM> between the spaced-apart (e.g., open) and approximated (e.g., closed) positions. More specifically, urging drive rod <NUM> proximally pivots jaw member <NUM> relative to jaw member <NUM> towards the approximated (e.g., closed) position while urging drive rod <NUM> distally pivots jaw member <NUM> relative to jaw member <NUM> towards the spaced-apart (e.g., open) position. However, other suitable mechanisms and/or configurations for pivoting jaw member <NUM> relative to jaw member <NUM> between the spaced-apart and approximated positions in response to selective actuation of drive rod <NUM> are also contemplated. Drive rod <NUM> extends proximally from end effector assembly <NUM> through shaft <NUM> and into housing <NUM> wherein drive rod <NUM> is operably coupled with a jaw drive sub-assembly <NUM> (<FIG>) of gearbox assembly <NUM> to enable selective actuation of end effector assembly <NUM> to grasp tissue therebetween and apply a closure force within an appropriate jaw closure force range, as detailed below.

Tissue-contacting surfaces <NUM>, <NUM> of jaw members <NUM>, <NUM>, respectively, are at least partially formed from an electrically conductive material and are energizable to different potentials to enable the conduction of electrical energy through tissue grasped therebetween, although tissue-contacting surfaces <NUM>, <NUM> may alternatively be configured to supply any suitable energy, e.g., thermal, microwave, light, ultrasonic, ultrasound, etc., through tissue grasped therebetween for energy-based tissue treatment. Instrument <NUM> defines a conductive pathway (not shown) through housing <NUM> and shaft <NUM> to end effector assembly <NUM> that may include lead wires, contacts, and/or electrically-conductive components to enable electrical connection of tissue-contacting surfaces <NUM>, <NUM> of jaw members <NUM>, <NUM>, respectively, to an energy source (not shown), e.g., an electrosurgical generator, for supplying energy to tissue-contacting surfaces <NUM>, <NUM> to treat, e.g., seal, tissue grasped between tissue-contacting surfaces <NUM>, <NUM>.

With reference to <FIG>, as noted above, gearbox assembly <NUM> is disposed within housing <NUM> and includes an articulation sub-assembly <NUM>, a knife drive sub-assembly (not shown), and a jaw drive sub-assembly <NUM>. Articulation sub-assembly <NUM> is operably coupled between first and second inputs <NUM>, <NUM> (<FIG>), respectively, of gearbox assembly <NUM> and articulation cables <NUM> (<FIG>) such that, upon receipt of appropriate inputs into first and/or second inputs <NUM>, <NUM>, articulation sub-assembly <NUM> manipulates cables <NUM> (<FIG>) to articulate end effector assembly <NUM> in a desired direction relative to a longitudinal axis "L" defined by shaft <NUM>, e.g., to pitch and/or yaw end effector assembly <NUM>.

Knife drive sub-assembly (not shown) is operably coupled between fourth input <NUM> (<FIG>) of gearbox assembly <NUM> and knife tube (not shown) such that, upon receipt of appropriate input into fourth input <NUM>, knife drive sub-assembly (not shown) reciprocates the knife blade (not shown) between jaw members <NUM>, <NUM> to cut tissue grasped between tissue-contacting surfaces <NUM>, <NUM>.

Jaw drive sub-assembly <NUM> is operably coupled between third input <NUM> (<FIG>) of gearbox assembly <NUM> and drive rod <NUM> such that, upon receipt of appropriate input into third input <NUM>, jaw drive sub-assembly <NUM> pivots jaw members <NUM>, <NUM> between the spaced-apart and approximated positions to grasp tissue therebetween and apply a closure force within an appropriate closure force range.

Gearbox assembly <NUM> is configured to operably interface with a robotic surgical system <NUM> (<FIG>) when instrument <NUM> is mounted on robotic surgical system <NUM> (<FIG>), to enable robotic operation of gearbox assembly <NUM> to provide the above-detailed functionality. That is, robotic surgical system <NUM> (<FIG>) selectively provides inputs to inputs <NUM>, <NUM>, <NUM>, <NUM> of gearbox assembly <NUM> to articulate end effector assembly <NUM>, grasp tissue between jaw members <NUM>, <NUM>, and/or cut tissue grasped between jaw members <NUM>, <NUM>. However, it is also contemplated that gearbox assembly <NUM> be configured to interface with any other suitable surgical system, e.g., a manual surgical handle, a powered surgical handle, etc. For the purposes herein, robotic surgical system <NUM> (<FIG>) is generally described.

Turning to <FIG>, robotic surgical system <NUM> is configured for use in accordance with the present disclosure. Aspects and features of robotic surgical system <NUM> not germane to the understanding of the present disclosure are omitted to avoid obscuring the aspects and features of the present disclosure in unnecessary detail.

Robotic surgical system <NUM> generally includes a plurality of robot arms <NUM>, <NUM>; a control device <NUM>; and an operating console <NUM> coupled with control device <NUM>. Operating console <NUM> may include a display device <NUM>, which may be set up in particular to display three-dimensional images; and manual input devices <NUM>, <NUM>, by means of which a person, e.g., a surgeon, may be able to telemanipulate robot arms <NUM>, <NUM> in a first operating mode. Robotic surgical system <NUM> may be configured for use on a patient <NUM> lying on a patient table <NUM> to be treated in a minimally invasive manner. Robotic surgical system <NUM> may further include a database <NUM>, in particular coupled to control device <NUM>, in which are stored, for example, pre-operative data from patient <NUM> and/or anatomical atlases.

Each of the robot arms <NUM>, <NUM> may include a plurality of members, which are connected through joints, and mounted devices which may be, for example, a surgical tool "ST. " One or more of the surgical tools "ST" may be instrument <NUM> (<FIG>), thus providing such functionality on a robotic surgical system <NUM>.

Robot arms <NUM>, <NUM> may be driven by electric drives, e.g., motors, connected to control device <NUM>. Control device <NUM>, e.g., a computer, may be configured to activate the motors, in particular by means of a computer program, in such a way that robot arms <NUM>, <NUM>, and, thus, their mounted surgical tools "ST" execute a desired movement and/or function according to a corresponding input from manual input devices <NUM>, <NUM>, respectively. Control device <NUM> may also be configured in such a way that it regulates the movement of robot arms <NUM>, <NUM> and/or of the motors.

With reference to <FIG>, articulation sub-assembly <NUM> of gearbox assembly <NUM> is shown generally including a first input shaft <NUM>, a second input shaft <NUM>, a proximal plate <NUM>, a middle plate <NUM>, a proximal center gear <NUM>, and a distal center gear <NUM>. The articulation sub-assembly <NUM> also includes a first lead screw <NUM> threadingly coupled to a first nut <NUM>, a second lead screw <NUM> threadingly coupled to a second nut <NUM>, a third lead screw <NUM> threadingly coupled to a third nut <NUM>, and a fourth lead screw <NUM> threadingly coupled to a fourth nut <NUM>. Rotation of lead screws <NUM>, <NUM>, <NUM>, <NUM> effects longitudinal translation of the respective nut <NUM>, <NUM>, <NUM>, <NUM> which are coupled to proximal portions of respective articulation cables <NUM> (<FIG>) to articulate end effector assembly <NUM> relative to a longitudinal axis "L" defined by shaft <NUM>. In particular, each of nuts <NUM>, <NUM>, <NUM>, <NUM> includes a cable connector 312c, 314c, 316c, 318c (<FIG>) for coupling to a proximal portion of each articulation cable <NUM>.

Middle plate <NUM> includes a middle plate stem <NUM> extending proximally therefrom for supporting the proximal center gear <NUM> and the distal center gear <NUM>. Proximal center gear <NUM> is rotatable around the middle plate stem <NUM> and includes a proximal gear portion 222p and a distal gear portion 222d. Proximal gear portion 222p and distal gear portion 222d may have different diameters. The distal gear portion 222d of the proximal center gear <NUM> is meshingly engaged with a gear portion <NUM> of the first lead screw <NUM>. Distal center gear <NUM> is rotatable around the middle plate stem <NUM> and includes a proximal gear portion 224p and a distal gear portion 224d. Proximal gear portion 224p and distal gear portion 224d may have different diameters. The distal gear portion 224d of the distal center gear <NUM> is meshingly engaged with a gear portion <NUM> of the second lead screw <NUM>. The proximal gear portion 224p of the distal center gear <NUM> is aligned with the waist portion 302w of the first lead screw <NUM>.

First input shaft <NUM> includes a gear portion <NUM> meshingly engaged with the proximal gear portion 222p of the proximal center gear <NUM> such that rotation of the first input shaft <NUM> causes rotation of the proximal center gear <NUM> and, in turn, the first lead screw <NUM>. Second input shaft <NUM> includes a gear portion <NUM> meshingly engaged with the proximal gear portion 224p of the distal center gear <NUM> such that rotation of the second input shaft <NUM> causes rotation of the distal center gear <NUM> and, in turn, the second lead screw <NUM>.

Third lead screw <NUM> includes a gear portion <NUM>, a waist portion 306w, and an elongate threaded body portion 306t. The gear portion <NUM> of the third lead screw <NUM> is meshingly engaged with the distal gear portion 222d of the proximal center gear <NUM> such that rotation of the proximal center gear <NUM> causes rotation of the third lead screw <NUM>. The waist portion 306w of the third lead screw <NUM> is aligned with the proximal gear portion 224p of the distal center gear <NUM>. As described above, third nut <NUM> is threadingly engaged with the elongate threaded body portion 306t of the third lead screw <NUM>. With this configuration, rotation of the third lead screw <NUM>, by means of rotation of the proximal center gear <NUM>, effects longitudinal translation of the third nut <NUM>.

Fourth lead screw <NUM> includes a gear portion <NUM> and an elongate threaded body portion 308t. The gear portion <NUM> of the fourth lead screw <NUM> is meshingly engaged with the distal gear portion 224d of the distal center gear <NUM> such that rotation of the distal center gear <NUM> causes rotation of the fourth lead screw <NUM>. As described above, fourth nut <NUM> is threadingly engaged with the elongate threaded body portion 308t of the fourth lead screw <NUM>. With this configuration, rotation of the fourth lead screw <NUM>, by means of rotation of the distal center gear <NUM>, effects longitudinal translation of the fourth nut <NUM>.

As best illustrated in <FIG>, proximal plate <NUM> includes an alignment portion <NUM> which serves to maintain longitudinal alignment between the first input shaft <NUM> and the first lead screw <NUM>. Similarly, middle plate <NUM> includes an alignment portion <NUM> which serves to maintain longitudinal alignment between the second input shaft <NUM> and the second lead screw <NUM>.

Articulation sub-assembly <NUM> also includes guide bars <NUM>, <NUM>, <NUM>, <NUM> which serve to maintain alignment between the internal components to which they are coupled and to prevent rotation of nuts <NUM>, <NUM>, <NUM>, <NUM> as lead screws <NUM>, <NUM>, <NUM>, <NUM> are rotated. In particular, a first guide bar <NUM> is disposed within the housing <NUM> and is operably coupled to the middle plate <NUM> and the first nut <NUM>. The first guide bar <NUM> inhibits rotation of the first nut <NUM> relative to the first lead screw <NUM> during rotation of the first lead screw <NUM> thereby enabling longitudinal translation of the first nut <NUM> therealong. A second guide bar <NUM> is also disposed within the housing <NUM> and is operably coupled to the middle plate <NUM> and the second nut <NUM>. The second guide bar <NUM> is configured to inhibit rotation of the second nut <NUM> relative to the second lead screw <NUM> during rotation of the second lead screw <NUM> thereby enabling longitudinal translation of the second nut <NUM> therealong. Additionally, a third guide bar <NUM> is disposed within the housing <NUM> and is operably coupled to the middle plate <NUM> and the third nut <NUM>. The third guide bar <NUM> is configured to inhibit rotation of the third nut <NUM> relative to the third lead screw <NUM> during rotation of the third lead screw <NUM> thereby enabling longitudinal translation of the third nut <NUM> therealong. Finally, a fourth guide bar <NUM> is also disposed within the housing <NUM> and is operably coupled to the middle plate <NUM> and the fourth nut <NUM>. The fourth guide bar <NUM> inhibits rotation of the fourth nut <NUM> relative to the fourth lead screw <NUM> during rotation of the fourth lead screw <NUM> thereby enabling longitudinal translation of the fourth nut <NUM> therealong.

Although described above as one guide bar being coupled to one nut for inhibiting rotation of the nut, more than one guide bar may be coupled to a single nut, for example, two guide bars to inhibit a single nut's rotation. For example, first guide bar <NUM> and second guide bar <NUM> may be operably coupled to the first nut <NUM> for inhibiting rotation of the first nut <NUM>, second guide bar <NUM> and third guide bar <NUM> may be operably coupled to the second nut <NUM> for inhibiting rotation of the second nut <NUM>, third guide bar <NUM> and fourth guide bar <NUM> may be operably coupled to the third nut <NUM> for inhibiting rotation of the third nut <NUM>, and fourth guide bar <NUM> and first guide bar <NUM> may be operably coupled to the fourth nut <NUM> to inhibit rotation of the fourth nut <NUM>.

As described above, with respect to articulation of end effector assembly <NUM> relative to proximal segment <NUM> of shaft <NUM>, actuation of articulation cables <NUM> may be effected in pairs. More specifically, in order to pitch end effector assembly <NUM>, the upper pair of cables <NUM> are actuated in a similar manner while the lower pair of cables <NUM> are actuated in a similar manner relative to one another but an opposite manner relative to the upper pair of cables <NUM>. With respect to yaw articulation, the right pair of cables <NUM> are actuated in a similar manner while the left pair of cables <NUM> are actuated in a similar manner relative to one another but an opposite manner relative to the right pair of cables <NUM>. Such actuation (e.g., pulling or providing slack) of articulation cables <NUM> are caused by the rotation of first input shaft <NUM> and second input shaft <NUM>, which through the geared coupling of the components of articulation sub-assembly <NUM> described above, ultimately effect longitudinal translation of each of nuts <NUM>, <NUM>, <NUM>, <NUM> which are coupled to respective proximal portions of articulation cables <NUM>.

As described above, end effector assembly <NUM> includes a first jaw member <NUM> and a second jaw member <NUM> with the first jaw member <NUM> movable relative to the second jaw member <NUM> between an open position and a closed position to grasp tissue therebetween. Jaw drive sub-assembly <NUM> is operably coupled to at least one of the first jaw member <NUM> or the second jaw member <NUM> and is configured to move the first jaw member <NUM> relative to the second jaw member <NUM> between the open position and the closed position.

With reference to <FIG>, jaw drive sub-assembly <NUM> of gearbox assembly <NUM> is shown generally including an input shaft <NUM>, a spring force assembly <NUM> operably coupled to the input shaft <NUM>, and a drive rod <NUM> operably coupled to the input shaft <NUM> via the spring force assembly <NUM>. In particular, a proximal portion of drive rod <NUM> is coupled to the spring force assembly <NUM> and a distal portion of drive rod <NUM> is coupled to one of first jaw member <NUM> or second jaw member <NUM> such that longitudinal translation of the spring force assembly <NUM> (or one or more of its components) pushes or pulls the drive rod <NUM> to move at least one of the first jaw member <NUM> or the second jaw member <NUM> relative to the other. The spring force assembly <NUM> is configured to maintain a jaw force between the first jaw member <NUM> and the second jaw member <NUM> during articulation of the end effector assembly <NUM>.

Input shaft <NUM> includes a proximal end portion <NUM> operably coupled to third input <NUM> (<FIG>) such that rotation of third input <NUM> effects rotation of input shaft <NUM>. That is, rotational input provided to third input 130drives rotation of input shaft <NUM>. Spring force assembly <NUM> is coupled to input shaft <NUM> and includes a proximal hub <NUM>, a distal hub <NUM>, a compression spring <NUM>, and a lock plate <NUM>. Spring force assembly <NUM> may further include a guide bar <NUM>, or alternatively may be coupled to any of guide bars <NUM>, <NUM>, <NUM>, <NUM> described above.

Proximal hub <NUM> includes a transverse slot <NUM> defined therethrough that is configured to receive lock plate <NUM>, as detailed below, to fix lock plate <NUM> and, thus, a proximal end portion of drive rod <NUM> relative to proximal hub <NUM> (see <FIG>). Once engaged in this manner, drive rod <NUM> is locked in position and coaxially disposed through proximal hub <NUM>, and distal hub <NUM>. In particular, a proximal portion of the drive rod <NUM> includes a key <NUM> and the lock plate <NUM> defines a key hole <NUM> configured to receive the key <NUM> to releasably secure the drive rod <NUM> to the proximal hub <NUM>.

Compression spring <NUM> is disposed around an elongate hub stem <NUM> of proximal hub <NUM>. Distal hub <NUM> is disposed around a distal portion of the compression spring <NUM> and movable relative to the proximal hub <NUM> with the biasing force provided by the compression spring <NUM> positioned therebetween. A distal portion of the elongate hub stem <NUM> includes a wing 452w extending radially outward therefrom which is configured to engage a shelf <NUM> of the distal hub <NUM>. With this configuration, distal translation of the distal hub <NUM> is inhibited beyond the wing 452w thereby defining a maximum distance between the proximal hub <NUM> and the distal hub <NUM>.

With reference to <FIG>, elongate hub stem <NUM> of proximal hub <NUM> is positioned through an opening defined by the distal hub <NUM> while in a first orientation and then is turned, for example a quarter turn, relative to the distal hub <NUM> to engage the shelf <NUM> of the distal hub <NUM> to the wing 452w of the proximal hub <NUM>. The compression spring <NUM> provides an outward force against the distal hub <NUM> to maintain engagement between the shelf <NUM> of the distal hub <NUM> to the wing 452w of the proximal hub <NUM>.

An elongate threaded body portion <NUM> of input shaft <NUM> is threadingly engaged with a threaded bore 454t of the distal hub <NUM> such that rotation of the input shaft <NUM> causes longitudinal translation of the distal hub <NUM>. Each of a retainer guide <NUM> of the proximal hub <NUM> and a retainer guide <NUM> of the distal hub <NUM> are operably coupled to a guide bar <NUM> to inhibit rotation of the distal hub <NUM> relative to the proximal hub <NUM> and maintain alignment therebetween as the input shaft <NUM> is rotated.

In use, jaw members <NUM>, <NUM> are initially disposed in the open position and, correspondingly, proximal and distal hubs <NUM>, <NUM> are disposed in a distal-most position such that drive rod <NUM> is disposed in a distal-most position. Further, in this position, compression spring <NUM> is disposed in a least-compressed condition; although, as noted above, even in the least-compressed condition, compression spring <NUM> is partially compressed due to the retention of compression spring <NUM> between proximal and distal hubs <NUM>, <NUM>.

In response to an input to close end effector assembly <NUM>, e.g., rotational input to third input <NUM>, input shaft <NUM> is rotated such that distal hub <NUM> is translated proximally towards proximal hub <NUM>. Proximal translation of distal hub <NUM> urges distal hub <NUM> against compression spring <NUM>. Initially, where forces resisting approximation of jaw members <NUM>, <NUM> are below a threshold corresponding to the spring value of compression spring <NUM>, the closure force applied by jaw members <NUM>, <NUM> is relatively low such that the urging of distal hub <NUM> proximally against compression spring <NUM> urges compression spring <NUM> proximally which, in turn, urges proximal hub <NUM> and lock plate <NUM> and, thus, drive rod <NUM> proximally to pivot first jaw member <NUM> relative to second jaw member <NUM> from the spaced-apart position towards the approximated position to grasp tissue therebetween.

Upon further approximation of jaw members <NUM>, <NUM> to grasp tissue therebetween, the forces resisting approximation of jaw members <NUM>, <NUM>, e.g., tissue resisting compression, may reach the threshold and, thus the closure force applied by jaw members <NUM>, <NUM> may reach a corresponding threshold. In order to maintain the closure force applied by jaw members <NUM>, <NUM> within a closure force range such as, for example, from about <NUM>/cm<NUM> to about <NUM>/cm<NUM>, application of further closure force by jaw members <NUM>, <NUM> is inhibited beyond this point despite further rotational input to third input <NUM>. More specifically, once the threshold has been reached, further rotational input to third input <NUM> rotates input shaft <NUM> to translate distal hub <NUM> further proximally into compression spring <NUM>. However, rather than compression spring <NUM> urging proximal hub <NUM> further proximally to continue approximation of jaw members <NUM>, <NUM> and increase the closure force applied therebetween, compression spring <NUM> is compressed, enabling proximal hub <NUM> and, thus, drive rod <NUM> to remain in position, thus inhibiting application of additional closure force between jaw members <NUM>, <NUM>.

With tissue grasped between jaw members <NUM>, <NUM> under an appropriate closure force, energy may be supplied to jaw members <NUM>, <NUM> to treat (e.g., seal) tissue. Thereafter, the knife blade (not shown) may be advanced between jaw members <NUM>, <NUM> to cut the treated tissue.

Once tissue is cut or otherwise treated or grasped, an opposite rotation input is provided to fourth input <NUM> to return the knife blade (not shown) to its initial position proximally of body portions 43b, 45b of jaw members <NUM>, <NUM> (see <FIG>). Thereafter, an opposite input is provided to third input <NUM> to return jaw members <NUM>, <NUM> back towards the spaced-apart position to release the sealed, grasped, and/or cut tissue.

It will be understood that various modifications may be made to the aspects disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various aspects. Those skilled in the art will envision other modifications within the scope of the claims appended thereto.

Claim 1:
A surgical instrument (<NUM>) comprising:
a housing (<NUM>);
a shaft (<NUM>) extending from the housing and defining a longitudinal axis ("L");
an end effector (<NUM>) operably coupled to a distal portion (<NUM>) of the shaft; and
a gearbox assembly (<NUM>) disposed within the housing (<NUM>) and including an articulation sub-assembly (<NUM>) configured to articulate the end effector (<NUM>) about the longitudinal axis defined by the shaft (<NUM>), the articulation sub-assembly including:
a first lead screw (<NUM>) including a gear portion (<NUM>), a waist portion (302w), and an elongate threaded body portion; and
a first nut (<NUM>) threadingly engaged with the elongate threaded body portion of the first lead screw (<NUM>) such that rotation of the first lead screw effects longitudinal translation of the first nut;
wherein
the articulation sub-assembly (<NUM>) further comprises:
a second lead screw (<NUM>) including a gear portion (<NUM>) and an elongate threaded body portion;
a second nut (<NUM>) threadingly engaged with the elongate threaded body portion of the second lead screw (<NUM>) such that rotation of the second lead screw effects longitudinal translation of the second nut;
a middle plate (<NUM>) including a middle plate stem (<NUM>) extending proximally therefrom;
a proximal center gear (<NUM>) operably coupled to and rotatable around the middle plate stem (<NUM>) and including a proximal gear portion (222p) and a distal gear portion (222d), the distal gear portion of the proximal center gear meshingly engaged with the gear portion (<NUM>) of the first lead screw (<NUM>); and
a distal center gear (<NUM>) operably coupled to and rotatable around the middle plate stem (<NUM>) and including a proximal gear portion (224p) and a distal gear portion (<NUM>), the distal gear portion of the distal center gear meshingly engaged with the gear portion (<NUM>) of the second lead screw (<NUM>) and the proximal gear portion of the distal center gear aligned with the waist portion (302w) of the first lead screw (<NUM>).