BACKGROUND

Minimally invasive surgical techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. As a consequence, the average length of a hospital stay for standard surgery may be shortened significantly using minimally invasive surgical techniques. Also, patient recovery times, patient discomfort, surgical side effects, and time away from work may also be reduced with minimally invasive surgery.

A common form of minimally invasive surgery is endoscopy, and a common form of endoscopy is laparoscopy, which is minimally invasive inspection and/or surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient's abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately one-half inch or less) incisions to provide entry ports for laparoscopic instruments.

Laparoscopic surgical instruments generally include an endoscope (e.g., laparoscope) for viewing the surgical field and tools for working at the surgical site. The working tools are typically similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by an extension tube (also known as, e.g., an instrument shaft or a main shaft). The end effector can include, for example, a clamp, grasper, scissor, stapler, cautery tool, linear cutter, or needle holder.

To perform surgical procedures, the surgeon passes working tools through cannula sleeves to an internal surgical site and manipulates them from outside the abdomen. The surgeon views the procedure from a monitor that displays an image of the surgical site taken from the endoscope. Similar endoscopic techniques are employed in, for example, arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like.

Minimally invasive telesurgical robotic systems are being developed to increase a surgeon's dexterity when working on an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location (outside the sterile field). In a telesurgery system, the surgeon is often provided with an image of the surgical site at a control console. While viewing a three dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the control console. Each of the master input devices controls the motion of a servo-mechanically actuated/articulated surgical instrument. During the surgical procedure, the telesurgical system can provide mechanical actuation and control of a variety of surgical instruments or tools. Many of the telesurgical tools have jaws or other articulatable end effectors that perform various functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, dissecting tissue, or the like, in response to manipulation of the master input devices. Tools having distal wrist joints allow the surgeon to orient the tool within the internal surgical site, greatly enhancing the freedom with which the surgeon can interact with (and treat) the tissue in real time.

Telesurgical systems are finding increasing applications by surgeons for growing variety of therapies. New tools would help to continue this growth, and particularly tools such as staplers, linear cutters, and the like (which are capable of imposing significant clamping and other forces against the internal tissues). Unfortunately, it can be challenging to transmit the desired telesurgical end effector forces through known tool wrists, particularly while retaining the response time, precision, flexibility, and reliability in the tool that is desired for telesurgical tasks.

For example, non-robotic surgical tools comprising linear clamping, cutting, and stapling devices have been employed in many different surgical procedures. Such a tool can be used to resect a cancerous or anomalous tissue from a gastro-intestinal tract. Unfortunately, many known surgical tools, including known linear clamping, cutting, and stapling tools, lack the ability to transmit desired torques (e.g., tissue clamping torque) or forces (e.g., staple firing force) across a compact articulated wrist, which may reduce the effectiveness of the surgical tool. Alternative tools with a shaft driven clamping mechanism also fail to provide rotational movement of an end effector to mimic the natural action of a surgeon's wrist.

For the reasons given above, it is desirable to provide improved surgical and/or robotic wrist structures. It would also be desirable to provide improved minimally invasive surgical tools that include a wrist mechanism that mimics the natural action of a surgeon's wrist, while allowing enhanced end effector forces and a response time suitable for telesurgical control.

BRIEF SUMMARY

Surgical tools with a two degree-of-freedom wrist, and related methods, are provided. The disclosed surgical tools may be particularly beneficial when used in minimally invasive surgery. In many embodiments, an intermediate wrist member is pivotally coupled with a distal end of an instrument shaft so as to rotate about a first axis transverse to the shaft, and an end effector body is pivotally coupled to the intermediate member so as to rotate about a second axis transverse to the first axis. Such a two degree-of-freedom wrist can be used to articulate the end effector body in a way that mimics the natural action of a surgeon's wrist, thereby providing a desirable amount of maneuverability for the end effector body. In many embodiments, the intermediate member has an elongate shape. An elongate shape leaves adjacent areas free for the routing of actuation components, for example, actuation components that articulate the end effector body relative to the instrument shaft, and actuation components (e.g., control cables, drive shafts) that articulate one or more end effector features relative to the end effector body. In many embodiments, the two degree-of-freedom wrist includes internal passages for guiding control cables. Such internal passages can be configured to inhibit altering control cable tensions during pivoting about the first and second axes.

Exemplary embodiments provide wrist articulation via linked tension members. In many embodiments, an end effector is coupled with a distal end of an elongate shaft via a two degree-of-freedom joint so as to allow the end effector to be oriented within an internal surgical space. In the exemplary embodiments, opposed movements of tension members angularly orient the end effector relative to the shaft, and sliding interface surfaces between the tension members and the end effector vary positions of the tension members in correlation with the orientation of the end effector to inhibit undesirable changes in tension of the tension members. By inhibiting such changes in tension of the tension members, detrimental control cable slack and/or overstressing of surgical tool components may be avoided when the tension members are used as linked pairs, for example, with opposed tension members sharing a common linear drive mechanism (e.g., a motor driven capstan). Actuating the tension members in linked pairs may provide for smooth and responsive articulation of the end effector relative to the shaft. Wrist articulation by linked tension members can also be used to reduce the length of the surgical tool distal of the shaft, which may improve access in a confined body space, angle of access to body structures, and visibility of body structures.

Mechanisms for transmitting torque through an angle, minimally invasive surgical tools comprising a mechanism for transmitting torque through an angle, and related methods are also provided. The disclosed mechanisms can be used, for example, to transmit torque to a shaft driven actuation mechanism of a surgical end effector that is mounted to an instrument shaft via a two degree-of-freedom wrist. In many surgical applications (e.g., many minimally invasive surgical applications) it may be beneficial to use a surgical tool comprising a surgical end effector mounted to the distal end of an instrument shaft via a two degree-of-freedom wrist so as to mimic the (often relatively rapid) natural action of a surgeon's wrist. By actuating the end effector with a rotational shaft drive, a high level of force can be applied to tissues through a narrow shaft. For example, such a shaft driven mechanism can be used to articulate a clamping jaw of the end effector so as to generate a high clamping force. Exemplary embodiments can transmit sufficient torque through the angled wrist of a minimally invasive surgical tool using a relatively simple dual ball-and-socket joint system in which the ball ends are coupled together to constrain the socket angle, and in which pins traversing the sockets transfer torque. This simple arrangement lends itself to miniaturization for use in, for example, a surgical instrument. This simple arrangement may also improve the reliability of tools that transmit torque through angles exceeding 60 degrees, thereby allowing substantial reorientation of an end effector relative to an instrument shaft. In many embodiments, a rate of rotation of a drive shaft and a driven shaft are substantially equal even when the drive shaft and the driven shaft are non-parallel, which may help provide smooth transmission of torque through the angle.

In a first aspect, a minimally invasive surgical tool is provided. The surgical tool includes a tubular instrument shaft having a proximal end and a distal end with a bore there between, an end effector including an end effector body; an intermediate wrist member pivotally coupled with the distal end of the shaft and pivotally coupled with the end effector body; and an actuation system extending distally through the bore of the shaft so as to orient the end effector body and actuate the end effector. The instrument shaft has an instrument-shaft axis. Pivoting of the intermediate body relative to the shaft orients intermediate member about a first axis relative to the shaft. Pivoting of the end effector body relative to the intermediate member orients the end effector body about a second axis relative to the intermediate member. The first axis is transverse to the shaft axis. The second axis is transverse to the first axis. The intermediate member has an exterior width along the first axis and an exterior length along the second axis. The length is significantly different than the width so that the intermediate member has an elongate cross section. A portion of the actuation system is laterally separated from the elongate cross section of the intermediate member between the shaft and the end effector body.

The intermediate member can include one or more additional features and/or characteristics. For example, the width of the intermediate member can be less than one-fourth the length of the intermediate member. The first axis and the second axis can be within 2 mm of being coplanar. The first axis and the second axis can be coplanar. The intermediate member can include internal passages for guiding control cables of the actuation system between the instrument shaft and the end effector body.

The surgical tool can include one or more additional features and/or characteristics. For example, the surgical tool can include a first joint pivotally coupling the shaft to the intermediate member and a second joint pivotally coupling the intermediate member to the end effector body. The first joint can include a single pivot shaft extending along the first axis within the width of the intermediate member so that the first joint is disposed within a central region between the shaft and the end effector body clear of the laterally separated portion of the actuation system. The second joint can include first and second coaxial pivot shafts separated along the second axis. The intermediate member can include internal passages for guiding control cables of the actuation system between the instrument shaft and the end effector body and between the coaxial pivot shafts of the second joint. The surgical tool can include a support member fixedly coupled with the instrument shaft and pivotally coupled with the intermediate member for rotation about the first axis. The support member can include internal passages for guiding control cables of the actuation system routed between a bore of the instrument shaft and the end effector body. The guide surfaces can constrain the control cables so as to inhibit altering cable tensions during pivoting about the first and second axes.

The actuation system can include one or more additional features and/or characteristics. For example, the laterally separated portion of the actuation system can include a first rotatable drive shaft for driving a first actuation mechanism of the end effector. The first drive shaft can be routed between the end effector body and the bore so as to pass adjacent to a first side of the intermediate member. The laterally separated portion of the actuation system can include a second rotatable drive shaft for driving a second actuation mechanism of the end effector. The second drive shaft can be routed between the end effector body and the bore so as to pass adjacent to a second side of the intermediate member, the second side being opposite the first side. An orientation portion of the actuation system can be operable to vary the orientation of the end effector body relative to the instrument shaft about the first and second axes. The orientation portion can be back drivable so that forces applied to the end effector body so as to alter its orientation are transmitted proximally through the bore by the actuation system. An actuation of the end effector can include articulation of a joint of the end effector.

In another aspect, a method for manufacturing a minimally invasive surgical tool is provided. The method includes pivotally coupling an intermediate member to an instrument shaft for rotation about a first axis oriented non-parallel to an elongate direction of the instrument shaft, pivotally coupling an end effector to the intermediate member for rotation about a second axis oriented non-parallel to the first axis and the elongate direction, and coupling an actuation mechanism with the end effector. The actuation mechanism is operable to vary the orientation of the end effector relative to the elongate direction in two dimensions. At least a portion of the actuation mechanism is routed between the end effector and a bore of the instrument shaft so as to pass outside of and separated from at least one side of the intermediate member.

In the method for manufacturing a minimally invasive surgical tool, the intermediate member coupled to the instrument shaft, and to which the end effector is coupled, can include one or more additional features and/or characteristics. For example, the first axis can be normal to the second axis. At least one of the first axis or the second axis can be normal to the instrument-shaft elongate direction. The intermediate member can have an exterior width in the first-axis direction and a maximum exterior length in the second-axis direction that is greater than the width in the first-axis direction. The intermediate member can have a maximum exterior width in the first-axis direction that is less than one-third of the exterior length. In intermediate member can include internal passages for guiding control cables routed between the end effector and a bore of the instrument shaft. The guide surfaces can constrain the control cables so as to inhibit altering cable tensions during pivoting about the first and second axes.

The method can include further steps. For example, the method can further include routing end effector control cables through intermediate-member internal passages. The method can further include back driving the actuation mechanism by varying the orientation of the end effector relative to the instrument shaft so that forces applied to the end effector so as to alter its orientation are transmitted proximally through the bore by the actuation system. Actuation of the end effector can include articulating a joint of the end effector.

In another aspect, a minimally invasive surgical method is provided. The method includes inserting a surgical end effector of a tool to an internal surgical site via a minimally invasive aperture or natural orifice, pivoting an intermediate member of the tool relative to a shaft of the tool about a first joint so as to orient the intermediate member about a first axis relative to the shaft of the tool supporting the end effector, pivoting the end effector relative to the intermediate member about a second joint so as to orient the end effector about a second axis relative to the intermediate member, mechanically actuating the end effector with an actuation-system component that passes between the bore and the end effector laterally offset from a central joint. One of the first joint and the second joint includes the central joint, which is a centrally located joint disposed within a central portion of a cross section of the tool. In the method, an actuation of the end effector can include articulating a joint of the end effector.

In another aspect, a minimally invasive surgical tool is provided. The surgical tool includes an elongate first link, a second link, four attachment features disposed on the second link, and four tension members. The elongate first link has a distal end, a proximal end, and a first link axis defined there between. The first link has an axial bore. The second link is pivotally coupled with the distal end of the first link so as to orient the second link about a first axis and a second axis. The first and second axes are nonparallel to the first link axis. The first axis is nonparallel to the second axis. The four tension members extend distally from within the bore of the first link to the attachment features so that opposed axial movement of the tension members angularly orients the second link relative to the first link about the first and second axes. Interface surfaces between the tension members and the attachment features vary the positions of the tension members relative to the second link in correlation with angular orientations of the second link relative to the first link so as to inhibit changes in tension of the tension members.

The first and second axes can have one or more additional characteristics. For example, the first and second axes can be non-intersecting. The first and second axes can be separated by various distances, for example, by 2 mm or less. The first axis can be transverse to the first link axis and the second axis can be transverse to the first axis.

Each of the tension members can interact with a corresponding attachment feature so as to selectively constrain the motion of the tension member. For example, each of the tension members can pivot about a first associated center relative to one of the attachment features when the second link pivots about the first axis. Each of the tension members can pivot about a second associated center relative to one of the attachment features when the second link pivots about the second axis. The tension members can slidingly engage the attachment features. The interface surfaces can include curving cylindrical surfaces having circular cross-sections and curving interface axes, the circular cross-sections defining cross-sectional centers and the curving interface axes defining centers of curvature. Each of the first and second associated centers can correspond to a cross-sectional center or a center of curvature.

The attachment features can comprise a curved portion. For example, each of the attachment features can comprise a curved portion. Each of the tension members can comprise an attachment lug configured to slidingly receive one of the curved portions so as to slide against and along the curved portion when the second link pivots about one of the first and second axes. Each of the curved portions can comprise a centerline that lies in a plane perpendicular to the first axis or the second axis. Each of the curved portions can have a first radius of curvature about its curved centerline and a fixed center of curvature for its curved centerline. Each of the fixed centers of curvature can lie in a plane containing at least one of the first axis or the second axis. Each of the curved portion centerlines can be tangent to a plane containing at least one of the first axis or the second axis.

The attachment features can comprise an attachment lug. For example, each of the attachment features can comprise an attachment lug. Each of the tension members can comprise a curved portion configured to be slidingly received by one of the attachment lugs so that the curved portion slides within the attachment lug when the second link pivots about one of the first and second axes. Each of the attachment lugs can have a connection hole axis oriented parallel to the first axis or the second axis. Each connection hole axis can lie in a plane containing at least one of the first axis or the second axis. Each of the curved portions can comprise a curved centerline that lies in a plane perpendicular to the first axis or the second axis. Each of the curved portions can have a first radius of curvature about its curved centerline and a fixed center of curvature for its curved centerline. Each of the fixed centers of curvature can lie in a plane containing at least one of the first axis or the second axis. Each of the curved portion centerlines can be tangent to a plane containing at least one of the first axis or the second axis.

Diagonally opposed tension members can be paired together and actuated in common. For example, each of the attachment features can be offset from the first and second axes when viewed along the first link axis, with one of the attachment features being disposed in each quadrant defined by the first and second axes when viewed along the first link axis. A first diagonally opposed pair of the tension members can be actuated by at least one cable extending from a first tension member of the first diagonally opposed pair to a second tension member of the first diagonally opposed pair, with the at least one cable being wrapped around a first capstan. Varying positions of the first diagonally opposed pair of the tension members relative to the second link can inhibit variations in tension of the at least one cable which would be imposed if the tension members were coupled to the attachment features with spherical center joints. A second diagonally opposed pair of the tension members can be actuated by at least one cable extending from a first tension member of the second diagonally opposed pair to a second tension member of the second diagonally opposed pair, with the at least one cable being wrapped around a second capstan. Varying positions of the second diagonally opposed pair of the tension members relative to the second link can inhibit variations in tension of the at least one cable which would be imposed if the tension members were coupled to the attachment features with spherical center joints. The first diagonally opposed pair of the tension members is different from the second diagonally opposed pair of the tension members, and the second capstan is different from the first capstan.

In another aspect, a surgical tool is provided. The surgical tool comprises an elongate first link, a plurality of control cables, a second link, and a plurality of interface assemblies. The elongate first link has a distal end, a proximal end, and a first link axis defined there between. The first link has an axial bore. The plurality of control cables extends distally within the bore of the first link from a control cable actuation assembly disposed adjacent the proximal end of the first link. The second link is pivotally coupled with the distal end of the first link so as to orient the second link about a first axis and a second axis. The first and second axes are nonparallel to the first link axis. The first axis is nonparallel to the second axis. Each interface assembly couples one of the control cables with the second link so that axial movement of the control cables angularly orients the second link relative to the first link about the first and second axes. One of the interface assemblies comprises a length of curved portion and an attachment lug having an attachment lug hole sized to slidingly receive the curved portion. The attachment lug rotates about the curved portion when the second link rotates about the first axis and slides against and along the curved portion when the second link rotates about the second axis.

In many embodiments, the plurality of control cables comprises four control cables. Each of the interface assemblies can comprise a length of curved portion and an attachment lug having an attachment lug hole sized to slidingly receive the curved portion such that the attachment lug rotates about the curved portion when the second link rotates about the first axis and slides against and along the curved portion when the second link rotates about the second axis.

In another aspect, a method for manufacturing a surgical tool is provided. The method comprises pivotally coupling a second link to a first link to rotate about a first axis oriented non-parallel to an elongate direction of the first link and to rotate about a second axis oriented non-parallel to both the elongate direction of the first link and the first axis, coupling a tension member with each of four attachment features disposed on the second link, and coupling each of the tension members with an actuation mechanism operable to control the angular orientation of the second link relative to the first link in two dimensions by actuating the tension members. Each of the attachment features is offset from the first and second axes when viewed along the elongate direction of the first link. One of the attachment features is disposed in each quadrant defined by the first and second axes when viewed along the elongate direction of the first link. Each of the tension members extends distally from within the bore of the first link to one of the attachment features of the second link so that axial movement of the tension members angularly orients the second link relative to the first link about the axes. Interface surfaces between the tension members and the attachment features vary a position of the tension members relative to the second link in correlation with the angular orientation of the second link relative to the first link so as to inhibit changes in tension of the tension members.

Coupling each of the tension members with an actuation mechanism can comprise additional steps, for example, coupling a first tension member of the tension members with a first control cable. A second tension member of the tension members can be coupled with a second control cable, where the second tension member is diagonally opposite to the first tension member. The first and second control cables can be coupled with a first capstan of the actuation mechanism. A third tension member of the tension members can be coupled with a third control cable. A fourth tension member of the tension members can be coupled with a fourth control cable, where the fourth tension member is diagonally opposite to the third tension member. The third and fourth control cables can be coupled with a second capstan of the actuation mechanism.

In another aspect, a surgical instrument is provided. The surgical instrument comprises a first link, a second link comprising an attachment feature, a joint that couples the first and second links, and a tension member comprising an attachment lug. The attachment feature comprises a curved portion. The joint rotates around a first axis defined in a first plane and around a second axis defined in a second plane. The first and second planes are parallel to and offset from one another. The attachment lug is coupled to the attachment feature. The attachment lug rotates around the curved portion when the tension member rotates the joint around the first axis. The attachment lug slides against and along the curved portion when the actuation member rotates the joint around the second axis.

In another aspect, a mechanism for transmitting torque through an angle is provided. The mechanism includes a coupling member comprising a first end and a second end with a coupling axis defined there between, a coupling pin, a drive shaft having a drive axis and a distal end, and a driven shaft having a proximal end and a driven axis. The first end of the coupling member comprises a receptacle. The coupling pin extends across the receptacle. The drive shaft distal end is received within the receptacle. The drive shaft distal end comprises a slot receiving the coupling pin throughout a range of angles between the coupling axis and the drive axis so that rotation of the drive shaft produces rotation of the coupling member via the coupling pin. The proximal end of the driven shaft coupled with the second end of the coupling member so that rotation of the coupling member about the coupling axis produces rotation of the driven shaft about the driven axis. The drive shaft is coupled with the driven shaft so as to maintain corresponding angles between the drive axis and the coupling axis, and the driven axis and the coupling axis when an angle between the drive axis and the driven axis varies during rotation of the shafts.

A mechanism for transmitting torque through an angle can include one or more additional features and/or can have one or more additional characteristics. For example, the mechanism can further comprise a cross pin to couple the drive shaft with the coupling pin. The cross pin can be oriented transverse to the coupling pin and mounted for rotation relative to the drive shaft. An outer surface of the drive shaft distal end can comprise a spherical surface. The outer surface of the drive shaft can interface with the receptacle of the coupling member so as to axially constrain the drive shaft and receptacle relative to each other during spherical pivoting there between. The receptacle can comprise a spherical surface that interfaces with the drive shaft spherical surface. The drive shaft distal end can comprise a set of spherical gear teeth and the driven shaft proximal end can comprise a set of spherical gear teeth interfacing with the drive shaft gear teeth so as to maintain substantially equivalent angles between the drive axis and the coupling axis, and the driven axis and the coupling axis. In many embodiments, at least one of the drive shaft and the drive shaft gear teeth or the driven shaft and the driven shaft gear teeth are integrally formed. In many embodiments, the mechanism is operable to transmit torque through an angle exceeding 60 degrees.

In another aspect, a mechanism for transmitting torque through an angle is provided. The mechanism includes a drive shaft having a distal end and a drive axis, a driven shaft having a proximal end and a driven axis, and a coupling member coupled with each of the drive shaft distal end and the driven shaft proximal end so that rotation of the drive shaft about the drive axis produces rotation of the driven shaft about the driven axis. At least one of the drive shaft distal end or the driven shaft proximal end comprises a protrusion. The coupling member comprises a tubular structure defining a drive receptacle and a driven receptacle with a coupling axis defined there between. At least one of the drive receptacle or the driven receptacle comprises a slot configured to receive the at least one protrusion and accommodate the at least one protrusion through a range of angles between the drive shaft and the driven shaft. The protrusion interacts with the slot so as to transfer rotational motion between the drive shaft and the driven shaft. The drive shaft distal end engages the driven shaft proximal end so as to maintain corresponding angles between the drive axis and the coupling axis, and the driven axis and the coupling axis when an angle between the drive axis and the driven axis varies during rotation of the shafts. In many embodiments, the mechanism is operable to transmit torque through an angle exceeding 60 degrees.

In many embodiments, the drive shaft and the driven shaft interface with the coupling member so that the drive shaft and the driven shaft are constrained relative to the coupling member. For example, each of the drive shaft distal end and the driven shaft proximal end can comprise an outer surface interfacing with the drive receptacle and the driven receptacle, respectively, such that, for each shaft, an intersection point defined between the shaft axis and the coupling axis is axially affixed along the shaft axis and along the coupling axis. The outer surfaces of the drive shaft distal end and the driven shaft proximal end can comprise a spherical surface. The drive receptacle and the driven receptacle can comprise a spherical surface.

In many embodiments, the drive shaft distal end and the driven shaft proximal end comprise interfacing gear teeth. For example, the drive shaft distal end can comprise a drive shaft gear tooth surface extending around the drive axis, the driven shaft proximal end can comprise a driven shaft gear tooth surface extending around the driven axis, and the drive shaft gear tooth surface can engage the driven shaft gear tooth surface so as maintain correspondence between the angles. In many embodiments, at least one of the drive shaft and the drive shaft gear tooth surface or the driven shaft and the driven shaft gear tooth surface are integrally formed. In many embodiments, the drive shaft gear tooth surface is defined by a drive shaft gear tooth profile extending radially from the drive axis, the driven shaft gear tooth surface is defined by a driven shaft gear tooth profile extending radially from the driven axis, and the drive shaft gear tooth surface engages the driven shaft gear tooth surface so as maintain substantial equivalence between the drive/coupler angle and the driven/coupler angle. In many embodiments, the drive shaft gear tooth surface comprises a revolute surface defined by rotating the drive shaft gear tooth profile about the drive axis, and the driven shaft gear tooth surface comprises a revolute surface defined by rotating the driven shaft gear tooth profile about the driven axis.

In another aspect, a minimally invasive surgical tool is provided. The surgical tool includes an instrument shaft, a drive shaft having a distal end and a drive axis, a driven shaft having a proximal end and a driven axis, a coupling member coupling the drive shaft with the driven shaft so that a rate of rotation of the drive and driven shafts are substantially equal when the drive axis and the driven axis are non-parallel, and an end effector coupled with the instrument shaft so that an orientation of the end effector can be varied in two dimensions relative to the instrument shaft. The drive shaft is mounted for rotation within the instrument shaft. The end effector comprises an articulated feature coupled with the driven shaft so that a rotation of the driven shaft about the driven axis produces an articulation of the feature.

In many embodiments, the drive shaft is axially and rotationally coupled with the coupling member, the driven shaft is axially and rotationally coupled with the coupling member, and the drive shaft engages the driven shaft. For example, the coupling member can comprise a first end and a second end with a coupling axis defined there between and the drive shaft distal end can be axially and rotationally coupled with the coupling member first end so that rotation of the drive shaft about the drive axis produces rotation of the coupling member about the coupling axis. The driven shaft proximal end can be axially and rotationally coupled with the coupling member second end so that rotation of the coupling member about the coupling axis produces rotation of the driven shaft about the driven axis. The drive shaft distal end can engage the driven shaft proximal end so as to maintain corresponding angles between the drive axis and the coupling axis, and the driven axis and the coupling axis when an angle between the drive axis and the driven axis varies during rotation of the shafts. The drive shaft distal end can comprise spherical gear teeth and the driven shaft proximal end can comprise spherical gear teeth engaging the drive shaft gear teeth. In many embodiments, at least one of the drive shaft and the drive shaft gear teeth or the driven shaft and the driven shaft gear teeth are integrally formed.

In many embodiments, the tool further comprises a coupling pin coupling the coupling member with the drive shaft so as to transfer rotational motion between the drive shaft and the coupling member. For example, the tool can further comprise a coupling member first end receptacle, a coupling pin crossing the receptacle, a drive shaft distal end outer surface interfacing with the receptacle, and a drive shaft distal end slot receiving the coupling pin throughout a range of angles between the coupling axis and the drive axis. Interaction between the coupling pin and the slot can couple the drive shaft with the coupling member so that rotation of the drive shaft produces rotation of the coupling member. The mechanism can further comprise a cross pin to couple the drive shaft with the coupling pin. The cross pin can be oriented transverse to the coupling pin and mounted for rotation relative to the drive shaft.

In many embodiments, at least one of the drive shaft distal end or the driven shaft proximal end comprises a protrusion. The coupling member can comprise a tubular structure defining a drive receptacle and a driven receptacle along the coupling axis and at least one of the drive receptacle or the driven receptacle can comprise a slot configured to receive the protrusion and accommodate the protrusion through a range of angles between the drive axis and the driven axis. The protrusion can interact with the slot so as to transfer rotational motion between at least one of the drive shaft or the driven shaft and the coupling member.

For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings. Other aspects, objects and advantages of the invention will be apparent from the drawings and detailed description that follows.

