Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/06—Programme-controlled manipulators characterised by multi-articulated arms
  • B25J9/065—Snake robots
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/005—Flexible endoscopes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/28—Surgical forceps
  • A61B17/29—Forceps for use in minimally invasive surgery
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
  • A61B34/30—Surgical robots
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
  • A61B34/70—Manipulators specially adapted for use in surgery
  • A61B34/71—Manipulators operated by drive cable mechanisms
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
  • A61B34/70—Manipulators specially adapted for use in surgery
  • A61B34/76—Manipulators having means for providing feel, e.g. force or tactile feedback
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/00234—Surgical instruments, devices or methods for minimally invasive surgery
  • A61B2017/00292—Surgical instruments, devices or methods for minimally invasive surgery mounted on or guided by flexible, e.g. catheter-like, means
  • A61B2017/003—Steerable
  • A61B2017/00305—Constructional details of the flexible means
  • A61B2017/00314—Separate linked members
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/00234—Surgical instruments, devices or methods for minimally invasive surgery
  • A61B2017/00292—Surgical instruments, devices or methods for minimally invasive surgery mounted on or guided by flexible, e.g. catheter-like, means
  • A61B2017/003—Steerable
  • A61B2017/00318—Steering mechanisms
  • A61B2017/00323—Cables or rods
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B2017/00681—Aspects not otherwise provided for
  • A61B2017/0069—Aspects not otherwise provided for with universal joint, cardan joint
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/28—Surgical forceps
  • A61B17/29—Forceps for use in minimally invasive surgery
  • A61B2017/2901—Details of shaft
  • A61B2017/2908—Multiple segments connected by articulations
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
  • A61B34/30—Surgical robots
  • A61B2034/305—Details of wrist mechanisms at distal ends of robotic arms
  • A61B2034/306—Wrists with multiple vertebrae
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
  • A61B34/70—Manipulators specially adapted for use in surgery
  • A61B34/71—Manipulators operated by drive cable mechanisms
  • A61B2034/715—Cable tensioning mechanisms for removing slack
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/03—Automatic limiting or abutting means, e.g. for safety
  • A61B2090/031—Automatic limiting or abutting means, e.g. for safety torque limiting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/06—Programme-controlled manipulators characterised by multi-articulated arms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/10—Programme-controlled manipulators characterised by positioning means for manipulator elements
  • B25J9/104—Programme-controlled manipulators characterised by positioning means for manipulator elements with cables, chains or ribbons

Definitions

• the apparatus provides a transmission system design that utilizes the transmission member as an energy storing device, over a certain portion of input stroke, to achieve a specific desired performance of the surgical tool.
• the transmission member may be referred as jaw closure transmission member, or as jaw closure transmission cable, or as transmission cable, or as cable or the like.
• instruments adapted for laparoscopic surgery typically embody a relatively narrow shaft supporting an end effector (EE) at its distal end and a lever or handle at its proximal end. Arranging the shaft of such an instrument through the cannula allows a surgeon to manipulate the proximal handle from outside the body to cause the distal end effector to carry out a surgical procedure at a remote internal surgical site.
• EE end effector
• the handle and tool shaft can be directly connected and roll rotation of the entire handle may drive rotation of the entire tool shaft and end-effector.
• Some alternative laparoscopic tools such as, for example, US Patent No 8668702 exist where the handle is not directly connected to the tool shaft but via an input joint (e.g. comprising a pair of transmission strips) which still allow for roll rotation of the tool shaft and end-effector by way of handle rotation.
• handle body may be referred as handle reference, or as palm grip, or the handle shell or the like.
• a laparoscopic or endoscopic instrument may provide a surgeon with the ability to transfer high force loads from the proximal end of the tool to the distal end. These forces are transferred through the instrument through an Input, Output and Transmission Member Sub-System, where the sub-system consists of a mechanism, as seen in most surgical instruments such as US Patent No 5330502.
• the Input mechanism generally consists of an actuating lever body as an input and an output (for example, a shuttle coupled to the handle body via a 1 DoF slider joint). As a user actuates the handle lever, the motion is transferred to the shuttle, the amount that the shuttle displaces is based on the input mechanisms mechanical advantage, or transmission ratio.
• transmission ratio and mechanical advantage are both used in this document since as the transmission ratio and mechanical advantage are, in general, simply the inverse of each other.
• the attribute mechanical advantage is used
• the attribute transmission ratio is used.
• the output mechanism can have a varying mechanical advantage or transmission ratio over the output stroke.
• this varying mechanical advantage of both the input mechanism and the output mechanism have a certain desirable profile.
• the mechanical advantage at the initial segment of the stroke can be low because no force build up is required initially however the mechanical advantage at the end of the stroke needs to be high to allow a reasonable force input to be amplified into a large force output.
• the transmission members used in the prior art are generally stiff in the direction of transmission. However, this transmission member does not have to be rigid. In transmission system described here, the transmission member itself is designed to have a finite stiffness so that it acts as an energy storage member during certain portions of the input stroke of the device. This offers a unique performance of the device and has many benefits over rigid or highly stiff transmission members.
• jaw closure transmission systems that provide enhanced closure security and feel. These closure transmissions may be part of any appropriate apparatus, including medical devices (e.g., minimally invasive surgical tools), or any other application in which it is beneficial or desirable to have a jaw closure mechanism that may securely grip and provide feedback to the user on grip strength, as will be described herein.
• medical devices e.g., minimally invasive surgical tools
• jaw closure mechanism may securely grip and provide feedback to the user on grip strength, as will be described herein.
• the jaw closure transmission systems described herein may include rigid and compliant transmission elements, including an input (e.g., a jaw actuation input), an output (e.g., jaw mechanism), a transmission cable having a finite stiffness in a transmission direction, and rigid or flexible transmission guiding element, wherein the transmission element stores energy during closure transmission to achieve unique and desirable functionality.
• an input e.g., a jaw actuation input
• an output e.g., jaw mechanism
• a transmission cable having a finite stiffness in a transmission direction e.g., a transmission cable having a finite stiffness in a transmission direction
• rigid or flexible transmission guiding element e.g., a transmission cable having a finite stiffness in a transmission direction
• the transmission element stores energy during closure transmission to achieve unique and desirable functionality.
• the jaw closure transmission systems described herein may include three (or more) sub-systems that are serially connected that take an input, in the form of handle lever displacement and force from the user, and produce an output that presents as moving jaw displacement and clamp load.
• moving jaw may be referred as movable jaw, or as moveable jaw or as end-effector moving jaw, or as EE moving jaw or the like.
• the three sub-systems are as follows: (a) Input Sub-system: Handle Assembly; (b) Output Sub-system: Jaw Assembly; (c) Transmission Sub-system (e.g., transmission member, e.g. Cable, and transmission guide, e.g. Flexible Conduit).
• the Input Sub-system may include the input in a Handle Assembly that comprises a handle body or shell that serves as the local reference or ground, and a handle lever configured to receive user input in the form of closing or displacing the handle lever relative to the handle body.
• a Handle Assembly that comprises a handle body or shell that serves as the local reference or ground, and a handle lever configured to receive user input in the form of closing or displacing the handle lever relative to the handle body.
• the full closure displacement of the handle lever with respect to the handle body is referred to as the input stroke.
• the handle lever reaches a hard-stop relative to the handle body.
• there may be a single locking or latching feature that keeps the handle lever latched closed relative to the handle body.
• An unlatching/unlocking feature e.g., a releasable lock
• the handle assembly may also include a handle output (handle mechanism output) that connects to the transmission cable.
• the handle output may be a shuttle, a push rod, pull rod, etc.
• the output typically interfaces with the transmission member and provides an actuation motion to the proximal end of the Transmission Member.
• the handle mechanism is configured as a mechanical linkage system that translates the closing motion of the handle lever relative to the handle body to a corresponding actuation motion of the handle shuttle relative to the handle body.
• the handle mechanism provides a transmission ratio and mechanical advantage between the handle lever and the handle shuttle so as to produce the appropriate actuation displacement and force at the proximal end of the transmission member (e.g., appropriate cable tension and cable displacement) via the handle shuttle during the overall stroke of the handle lever (i.e., input stroke).
• This optimization may be based on the structure and functionality of the overall jaw closure transmission system including the input sub-system, transmission sub-system, and output sub-system, and in some variations may not be due to just the input sub-system.
• the handle mechanism may be designed such that instead of providing a constant mechanical advantage or transmission ratio, it produces a higher transmission ratio (e.g., lower mechanical advantage) in the first portion of the input stroke and a lower transmission ratio (higher mechanical advantage) in the second portion of the input stroke.
• a higher transmission ratio e.g., lower mechanical advantage
• a lower transmission ratio higher mechanical advantage
• the output sub-system typically includes an end-effector assembly or jaw assembly, and may include the following elements: an end-effector (e.g., jaw) base or end-effector fixed jaw that serves as the local reference or ground; an end-effector movable jaw coupled to the end-effector fixed jaw (e.g., pivotally coupled to the end-effector fixed jaw) such that it can open and close (i.e. displace) with respect the end- effector fixed jaw.
• an end-effector e.g., jaw
• an end-effector movable jaw coupled to the end-effector fixed jaw (e.g., pivotally coupled to the end-effector fixed jaw) such that it can open and close (i.e. displace) with respect the end- effector fixed jaw.
• the full closure displacement of the moving jaw relative to the fixed jaw may be referred to as the output stroke; in the devices described herein, the output stroke is always complete prior to completion of the input stroke, and is generally completed around the transition between the first portion of the input stroke and the second portion of the input stroke (e.g., between about 30% and 70% of the full input stroke, e.g., between about 40% and 60% of the full input stroke, between about 40% and 70% of the full input stroke, between about 45% and 60% of the full input stroke, etc.).
• the jaws of the jaw assembly are at a stop position, and will no longer close further (full output stroke), by the action of the handle assembly actuating the transmission cable.
• the handle assembly may continue to be actuated, in the second part of the input stroke, and may stretch the transmission cable. This stretch may be felt by the user operating the handle (as resistance in the handle) and the force being applied to stretch the cable may be transmitted to the jaws as a holding force between the jaws.
• a closure displacement of the Handle Lever relative to the Handle Body at the input of the Closure Transmission System may result in a closure displacement of the moving jaw relative to the fixed jaw to hold an object (such as needle, suture, tissue, staple, clip etc.) between the jaws.
• an object such as needle, suture, tissue, staple, clip etc.
• a pulley coupled to the fixed jaw may be configured to receive the actuation motion from the distal end of the transmission member.
• the jaw assembly may include a jaw mechanism, which may be a linkage, cam (e.g., cam surface and pin), etc.
• the jaw mechanism e.g. in some variations a drive pin / cam surface that translates the actuation motion of the jaw pulley relative to the fixed jaw to a corresponding closure motion of the moving jaw relative to the fixed jaw.
• a drive pin is driven by the pulley and interfaces with a camming surface on the moving jaw, providing a camming action.
• the distal end of the transmission member i.e. cable
• the pulley pulley is wrapped around the pulley pulley.
• the jaw mechanism is designed to provide a transmission ratio and mechanical advantage between the distal end of the transmission member and the moving jaw so as to produce the appropriate output displacement and force at the moving jaw relative to the fixed jaw during the overall stroke of the moving jaw (i.e. output stroke).
• This optimization may be based on the structure and functionality of the overall closure transmission system including the input sub-system, transmission sub-system, and output sub-system, and not just the output sub-system.
• the jaw assembly (end-effector) mechanism may be designed to provide a large mechanical advantage at the end of its stroke, to maximally amplify the force in the transmission member (i.e., tension in the jaw closure transmission cable) to a clamping force at the jaws. This implies that for a certain desired jaw clamping force, the transmission cable tension can be less, which has several advantages.
• the transmission sub-system may include a transmission member to transmit the closure action of the input sub-system (i.e. handle assembly) to the output sub-system (i.e. jaw assembly) of the closure transmission system. More specifically, the transmission member may transmit the actuation motion of the handle shuttle to a corresponding actuation motion of the jaw pulley.
• This transmission member may be a cable, braided rope, etc. that is capable of accommodating very tight bends as might necessary when the closure transmission system is part of a remote access tool or device.
• the transmission member may be highly compliant (i.e. flexible) in bending, twisting, and compression. This member is relatively stiffer in tension because it has to transmit force and displacement along this direction; but at the same time it is not chosen or designed to be infinitely or effectively infinitely stiff. Rather, it is intentionally designed or chosen to have a finite stiffness (or finite compliance) so that it can also serve as an inline spring. In general, nothing is infinitely stiff or infinitely compliant; infinite stiffness corresponds to zero compliance and zero stiffness corresponds to infinite compliance. Instead, stiffness may be scaled on a relative scale. For example, on some normalized scales a stiffness less than 10 is close to infinitely compliant and a stiffness greater than 1000 is closely to infinitely stiff. In any of the apparatuses described the axial stiffness of the transmission member may have a stiffness in the range of 100 may be used.
• any of these apparatuses may include a transmission guide that serves as a conduit or channel (also, a reference) for the Transmission Member.
• This proximal portion of this transmission guide is connected to the Input Sub-system reference (i.e. Handle Body) and the distal portion of this transmission guide is connected to the Output Sub-system reference (i.e. EE Fixed Jaw).
• This guide may be completely rigid in all directions such as a frame or a shaft or tube.
• this guide may be flexible in bending so that it can take an arbitrary tortuous shape but still remains very stiff (ideally, close to infinitely stiffness) axially (i.e. along its bent/deformed central axis).
• This guide may be flexible in bending so that it can take an arbitrary tortuous shape sand have an intermediate stiffness (i.e., have some intentionally finite compliance) in the axial direction (i.e., along its bent/deformed central axis).
• connections between the ends of the guide and respective references of the input and output subsystems maybe close to infinitely stiff in the transmission direction (i.e. axial direction of the transmission cable) or may have some intentionally finite compliance (i.e. slightly lower stiffness than infinitely stiff values).
• the three coupled sub-systems may allow for the use of cables as the primary transmission member.
• Cables are highly flexible in bending and therefore can be incorporated within minimal access tools / devices that have an input articulation joint between the handle and the tool frame/shaft, and an output articulation joint between the tool frame/shaft end-effector.
• the tool frame/shaft may also serve as a portion of or the entire transmission guide.
• the use of cable a transmission member enables a very tight bend at the output articulation joint. This helps facilitate the miniaturization of output articulating joint, and therefore the end effectors as well at the distal end of the minimal access tool / device.
• the choice of a cable as a transmission member and a flexible conduit as a transmission guide member facilitates a minimal access tool/device architecture where the handle assembly is not directly connected to a tool frame/shaft.
• the handle assembly "floats" with respect to the tool shaft/frame, and may be connected via a virtual center input articulating joint that is proximal to the handle assembly.
• the system may include either or both a flexible conduit as the transmission guide member to guide the transmission member (cable) from the handle assembly to the tool shaft/frame.
• the choice of a cable as the jaw closure transmission member in an articulating minimal access tool/device may also ensure a relative decoupling between the jaw closure functionality of the device and articulation functionality of the device. Since the transmission member itself does not have significant bending (i.e. articulation) stiffness, it does not significantly impact the articulation of the end- effector (jaw assembly). Assembly about the output articulation joint. Moreover, a large mechanical advantage in the jaw mechanism may result in a lower or limited tension in the transmission cable, which has several advantages listed in Point 3 below.
• This overall Jaw Closure Transmission System may enable jaw closure in two steps. During the first portion of the input stroke, as the handle lever moves from its fully open position to an approximately mid-way open position (typically about 30%-70% of the stroke), the moving jaw goes from it fully open position to its fully closed position. In this state, the jaw mechanism has achieved its full output stroke and has reached a hard-stop.
• This hard-stop may be the result of jaw on jaw contact, or the two jaws holding a needle in between. In either case, the jaw mechanism has reached a static state, while there is still input stroke remaining at the handle mechanism. This point onwards, the remaining stroke of the handle mechanism goes into axially stretching the transmission member (i.e. cable) and or axially compressing the transmission guide members.
• the intentional axial compliance selected in the transmission member and transmission guide member enables the user to continue to displace the Handle lever through the remaining portion (i.e. the second portion) of the Handle
• the Mechanism's overall Input Stroke During this second portion of the Input Stroke, the actuation motion of the Handle Shuttle causes the transmission member (e.g. cable) to stretch and/or Transmission Guide Member (e.g. flexible conduit) to compress since the distal end of the transmission member is static due to the static state of the jaw mechanism.
• the transmission member e.g. cable
• Transmission Guide Member e.g. flexible conduit
• the second portion of the Input Stroke corresponds to stretching the cable and an associated increase in tension of the cable (based on the compliance of the cable). This gradually increasing cable tension continues to serve as the input force on the jaw mechanism and continues to get amplified by the mechanical advantage of this mechanism (even though the mechanism itself is static due to a hard-stop at the jaws).
• the clamping force between the jaws (with or without a needle in between) keeps increasing as well.
• the first portion of the input stroke of the handle lever corresponds to an increasing displacement of the moving jaw from a fully open position to a fully closed position (i.e. total Output Stroke), which corresponds to a hard-stop at the jaws (with or without a needle);
• the second portion of the Input Stroke at the Handle Lever corresponds to a gradually increasing clamping force between the jaws (with or without a needle) at the EE Assembly.
• the embodiment may not only be present as a two-stage stroke, but also may be present as a three-stage stroke wherein the third stage relates to a region dedicated to facilitating Handle Lever locking.
• the Handle Lever angular displacement does not produce additional Transmission Member displacement, and therefore does not introduce any additional energy to the compliant transmission elements.
• the primary purpose of the third stage is to provide a single region where the Handle Mechanism locks into place. The presence of this third stage provides for an opportunity to optimize Handle Mechanism design for locking, rather than for facilitating Jaw
• the input force required throughout the third stage does not depend on the mechanical spring-rate property for the compliant transmission members, but rather merely depend on frictional losses between the members.
• the user input force in the third stage to lock the handle is significantly independent of needle location within the jaws of the Output Mechanism. This may result in several benefits for the user and in the design, including the substantial reduction in sudden step changes in the force feedback felt by the surgeon at the Handle Lever as needle contact or jaw contact happens.
• the presence of transmission member and/or transmission guide member compliance in the axial i.e.
• the transmission sub-system efficiently stores energy by means of stretching the transmission cable. This energy storage is not passive, in the sense that the stretching of the cable corresponds to an increase in cable tension, which when reflected through the mechanical advantage of the EE mechanism produces an increased jaw clamping force.
• the jaw closure transmission systems described herein may be a self-limiting and/or self- correcting and/or self-regulating system for limiting the maximum force that is transmitted via the transmission member in spite of variations in the presence and location of a an object (e.g., needle) in the jaws. This may advantageously lower the loads all members/components of the Jaw Closure
• these jaw closure transmission systems described herein may regulate needle clamp load which helps reduce damage to needles, and/or may desensitize the system from size and location of needle held between the jaws. Provides an adequate clamping force without damaging the needle.
• These jaw closure transmission systems may also regulate handle lever force applied by the surgeon which is preferred from an ergonomic standpoint. In the case of a rigid transmission member, it becomes very difficult for the surgeon to regulate the clamping force at the jaws by adjusting his input force/displacement at the handle lever.
• FIG. 3 illustrates one example of such a system, showing a handle reference 301 , handle mechanism 303, input lever/button 305, first transmission member 307, first transmission guide 309, intermediate transmission mechanism 31 1 , second transmission guide, 313, second transmission member 3 15, and jaw mechanism 317.
• an Input Sub-system and an Output Sub-system there may also be an Intermediate Sub-System with an Intermediate Mechanism.
• the use of an axially compliant transmission and transmission guide members may be preserved to achieve desired Jaw Closure performance.
• the handle input may be a lever, or any other input allowing a variable degree of actuation, which may generally be referred to herein as “levers”, including plungers, dials, knobs, etc.
• these jaw closure transmission systems may generally provide for connecting an input and an output comprising rigid and compliant transmission elements, as well as rigid and flexible transmission guiding elements, wherein the transmission elements with finite flexibility in the transmission direction also serves to store energy during closure transmission to achieve unique and desirable functionality.
• the system can be thought of as, but not limited to, three sub-systems that are serially connected that take an input, in the form of handle lever displacement by force from the user, and produce an output that presents as moving jaw displacement and clamp load.
• the three sub-systems (Input Sub-system which is referred to as the Handle Mechanism; Output Subsystem which is referred to as the Jaw Mechanism; and Transmission Sub-system which comprises of a Transmission Member, e.g. Cable, and Transmission Guide, e.g. Flexible Conduit) may be represented in a system diagram as shown in one example in FIG.1 .
• the example shown in FIG.1 The example shown in FIG.
• a handle body or handle shell 101 includes a handle assembly 103 comprising a handle mechanism, a handle lever 107 (input lever or input link), a transmission guide 109 (riding pulley) and/or flexible conduit 109' a transmission cable 1 1 1 , a return spring 1 13, a fixed jaw 1 15 (end effector base/reference) an end-effector assembly 1 17 comprising a jaw mechanism, a drive pin 121 , a pulley pivot pin 123, a pulley 1 19, and a jaw pivot pin 125.
• the input in a Handle Assembly may comprise a Handle Body or Shell that serves as the local reference or ground.
• the handle body is generally designed to be ergonomic for the user to hold in various positions since it is generally the articulation of the handle body which controls the location and orientation of the end effector.
• Mechanically the handle body can be directly connected to the end effector via a tool shaft as in straight stick laparoscopic instruments, serially or connected to the end effector thought through an input articulating joint, a tool frame (e.g. a frame, or a frame with a shaft extension, or a shaft), and an output articulating joint a series of joints which provide articulation to the end effector or even indirectly attached to the end effector as described in US Patent No 8668702.
• the Handle body houses an internal mechanism (or handle mechanism) consisting of a Handle Lever configured to receive user input in the form displacement relative to the Handle Body.
• Full Handle Lever displacement with respect to the handle body is referred to as the Input Stroke.
• This input stroke is based on the kinematic design of the handle mechanism and is limited by one more hard-stops in the handle mechanism.
• This input stroke is designed to have a specific mechanical advantage curve profile that, when combined with the other sub assembles, is unique to the type of surgical instrument.
• the mechanical advantage curve of the input sub-system initially comprises of a low mechanical advantage then increases to have a high mechanical advantage at the end of the input stroke.
• full closure i.e.
• the Handle Lever reaches a hard-stop relative to the Handle Body. At this hard stop, there may be a single locking or latching feature that keeps the Handle Lever latched closed relative to the Handle body. As mentioned above an unlatching/unlocking feature may unlock the Handle Lever and allow it to open again with respect to the Handle Body.
• the output of the Handle Mechanism is via the Handle Shuttle (or output member, pull rod, or push rod), which interfaces with the Transmission Member and provides an actuation motion to the proximal end of the Transmission Member.
• the output of the Handle Mechanism is not limited to a Shuttle, the embodiment shown consist of a "Shuttle" because the Handle Mechanism is a 6 bar linkage with a 1 DoF slider joint between the output member (shuttle) and handle body.
• the handle mechanism is not limited to a 6 bar linkage.
• the handle mechanism could be a simple lever, 4 bar linkage, cam slot, gear, etc.
• the Handle Mechanism may be configured to provide a varying transmission ratio and mechanical advantage between the Handle Lever and the Handle Shuttle so as to produce the appropriate actuation displacement and force at the proximal end of the Transmission Member (i.e. appropriate cable tension and cable displacement) via the Handle Shuttle during the overall stroke of the Handle Lever (i.e. Input Stroke).
• the Handle Mechanism itself may be take the form of various configurations.
• the linkage system may be a 4-bar linkage, or any alternate system containing a plurality of linkages or motion members that actuates the transmission member either by rotary of linear motion.
• any of the linkages contained within the linkage system could be driven by a cam purposefully designed to induce a variable mechanical advantage throughout the handle's jaw closure lever stroke.
• Fig. 13 shows an Input Sub-System consisting of a cam which achieves the desired variable mechanical advantage.
• the linkage system may be a compliant mechanism that achieves the desired constant or variable transmission ratio. This mechanism may lead to part count reduction by still achieving similar performance.
• the Handle Mechanism is designed such that instead of providing a constant mechanical advantage or transmission ratio, it is designed to produce a higher transmission ratio (lower mechanical advantage) in the first portion of the Input Stroke and a lower transmission ratio (higher mechanical advantage) in the second portion of the Input Stroke.
• the mechanism for input into the Input Sub-System generally includes an actuating lever body, or ground reference, and a Handle Input Lever
• the Input Sub-System may be embodied alternatively.
• the Input Sub-System may be embodied as a motion member capable of translating mechanical energy therein.
• the input motion member may be a button, dial, tension rod, or binary switch.
• the Output may generally be a Jaw Mechanism comprising a jaw base (which may include or be integral with a) fixed Jaw that serves as the local reference or ground (alternatively two moving jaws may be used), and the movable Jaw may be coupled to the Fixed Jaw (e.g., pivotally coupled to the Fixed Jaw) such that it can open and close (i.e. displace) with respect the Fixed Jaw.
• the structure of one end-effector (jaw assembly) embodiment is seen FIGS. 1 , 2, 1 1 1 , 12A, and 12B.
• the full closure displacement of the End Effector Moving Jaw relative to the End Effector Fixed Jaw is referred to as the Output Stroke.
• the purpose of this closure displacement of the End Effector Moving Jaw relative to the End Effector Fixed Jaw is to hold an object (such as needle, suture, tissue, staple, clip etc.) between the jaws in response to a corresponding closure displacement of the Handle Lever relative to the Handle Body at the input of the Closure Transmission System.
• the embodiment shown incorporates but is not limited to, a two stage mechanical mechanism to produce the desired mechanical advantage curve.
• the desired mechanical advantage curve being low mechanical advantage to start with and then high mechanical advantage at the end.
• the design is not limited to the current embodiment as long as the mechanical advantage curve is conserved.
• an End Effector Pulley coupled to the End Effector Fixed Jaw or the fixed bearing member e.g.
• a Jaw Mechanism e.g. comprising a drive pin / cam surface
• a Drive pin is driven by the end effector Pulley and interfaces with a camming surface on the Moving Jaw, providing a camming action.
• the distal end of the Transmission Member i.e. cable
• the End Effector Pulley is wrapped around the End Effector Pulley.
• a positive engagement feature between the cable and the pulley may be accomplished via a cylindrical member that is crimped onto the cable and sits in a cavity on the pulley.
• a Return Spring either in the jaw assembly, or on the transmission guide, or in the handle assembly. The purpose of this Return Spring is to open the jaws after fully closure is reached and the Handle Lever returns to the initial open angle.
• the End Effector mechanism is designed to provide a varying Transmission Ratio and Mechanical Advantage between the distal end of the Transmission Member and the End Effector Moving Jaw so as to produce the appropriate output displacement and force at the end effector Moving Jaw relative to the end effector Fixed Jaw during the overall stroke of the end effector Moving Jaw (i.e. Output Stroke).
• This optimization is based on the structure and functionality of the overall Closure Transmission System including the Input Sub-system, Transmission Sub-system, and Output Sub-System, and not just the Output Sub-system.
• the end effector mechanism is designed to provide a large mechanical advantage at the end of its stroke, to maximally amplify the force in the Transmission Member (i.e. tension in the jaw closure transmission cable) to a clamping force at the jaws.
• the end- effector may include many different embodiments but is not limited to a pair of jaws, useful for manipulation of needles, suture, tissue, cautery, ligation clip application, etc.
• the Transmission Sub-system may comprise the following elements, a Transmission Member to transmit the closure action of the Input Sub-system (i.e. Handle Assembly) to the Output Sub-System (i.e. end effector Assembly) of the Closure Transmission System. More specifically, the Transmission Member transmits the actuation motion of the Handle Shuttle to a corresponding actuation motion of the end effector Pulley. More specifically, this Transmission Member is a cable, braided rope, etc. that is capable of accommodating very tight bends as might necessary when the Closure Transmission System is part of a Remote Access Tool or Device as seen in FIGS. 1 , 10, 15 and 16. The transmission member is highly compliant (i.e. flexible) in bending, twisting, and compression.
• This member is relatively stiffer in tension because it has to transmit force and displacement along this direction; but at the same time it is not chosen or designed to be infinitely or effectively infinitely stiff. Rather, it is intentionally designed or chosen to have a finite stiffness (or finite compliance) so that it can also serve as an inline spring. The importance of this finite stiffness for the system level performance is described below. Note that that nothing is infinitely stiff or infinitely compliant. Infinite stiffness corresponds to zero compliance and zero stiffness corresponds to infinite compliance. On some normalized scale, a stiffness less than 10 is close to infinitely compliant and a stiffness greater than 1000 is closely to infinitely stiff. On such a scale, a stiffness in the range of 100-200 is where we might place the axial stiffness of the transmission member.
• a Transmission Guide that serves as a conduit or channel (also, a reference) for the Transmission Member.
• This proximal portion of this transmission guide is connected to the Input Sub-system reference (i.e. Handle Body) and the distal portion of this transmission guide is connected to the Output Sub-system reference (i.e. end effector Fixed Jaw).
• This guide may be completely rigid in all directions such as a frame or a shaft or tube as seen in Fig.2.
• This guide may also be flexible in bending so that it can take an arbitrary tortuous shape but still remains very stiff (ideally, close to infinitely stiffness) axially (i.e. along its bent/deformed central axis).
• this guide may be flexible in bending so that it can take an arbitrary tortuous shape and have an intermediate stiffness (i.e. have some intentionally finite compliance) in the axial direction (i.e. along its bent/deformed central axis).
• the connections between the ends of the guide and respective references of the input and output sub-systems maybe close to infinitely stiff in the transmission direction (i.e. axial direction of the transmission cable) or may have some intentionally finite compliance (i.e. slightly lower stiffness than infinitely stiff values).
• FIG. 2 shows a handle assembly 202 comprising a handle mechanism, a handle lever 201 (input link or input lever), a cable 207, a body body (or handle reference) 203, a return spring 205, a guide member 209, a fixed jaw 21 1 (end effector base or reference), an end effector assembly 213 comprising a jaw mechanism, a pulley 215, a pulley pivot pin
• the devices may include: an elongate transmission guide, wherein the transmission cable is routed through the transmission guide; a handle assembly at a proximal end of the elongate transmission guide, the handle assembly comprising a handle body, an input lever, a handle output coupled to the transmission cable, and a handle mechanism coupling the input lever to the handle output, wherein the handle mechanism has an input stroke consisting of a full closure displacement of the input lever relative to the handle body, further wherein the input stroke is divided into a first part and a second part, wherein the first part corresponds to a displacement of 30% to 70% of the full closure displacement of the input lever and the second part corresponds to the remaining displacement of the input lever; and wherein the jaw assembly is distal to the elongate transmission guide, the jaw assembly having a first jaw, a second jaw, ajaw input coupled to the transmission cable, and a jaw
• a medical device having a jaw assembly actuated by a transmission cable having a finite stiffness in a transmission direction may include: an elongate transmission guide comprising a flexible conduit, wherein the transmission cable is routed through the transmission guide; a handle assembly at a proximal end of the elongate transmission guide, the handle assembly comprising a handle body, an input lever, a handle output comprising a shuttle coupled to the transmission cable, and a handle mechanism comprising a six bar linkage coupling the input lever to the handle output, wherein the handle mechanism has an input stroke consisting of a full closure displacement of the input lever relative to the handle body, further wherein the input stroke is divided into a first part and a second part, wherein the first part corresponds to a displacement of 30% to 70% of the full closure displacement of the input lever and the second part corresponds to the remaining displacement of the input lever; and wherein the jaw assembly is distal to the elongate transmission guide, the jaw assembly having a first jaw, a second jaw, ajaw input compris
• the handle mechanism may be a linkage (e.g., six-bar linkage, four-bar linkage, etc.) or a cam (cam surface and pin, etc.).
• the elongate transmission guide may comprise a flexible conduit or elongate shaft or both.
• the transmission cable may generally have a finites stiffness in the direction of transmission (e.g., along the length of the extended cable).
• the transmission cable may have a stiffness in a transmission direction of less than 800 pounds per inch, less than 700 pounds per inch, less than 650 pounds per inch, less than 600 pounds per inch, less than 500 pounds per inch, less than 400 pounds per inch, etc. (and in some variations be greater than 100 pounds per inch, greater than 150 pounds per inch, greater than 200 pounds per inch, greater than 250 pounds per inch, greater than 300 pounds per inch, etc., e.g., between 100 and 650 pounds per inch, etc.).
• the handle mechanism may be configured to provide a first mechanical advantage during the first part of the input stroke and a second mechanical advantage that is greater than the first mechanical advantage during the second part of the input stroke.
• the handle output may comprise one or more of: a shuttle, a push rod, or a pull rod.
• the device may include a jaw base to which either or both the first and second jaws are pivotally coupled.
• the jaw input may comprise a jaw pulley
• the jaw mechanism may comprise a cam surface between the jaw pulley and the second jaw.
• any of these devices may include a releasable latching mechanism configured to hold the handle lever locked in a closed position at the end of the input stroke.
• a medical device to close a jaw assembly of the medical device, wherein the medical device comprises an elongate transmission guide, a finite stiffness transmission cable within the transmission guide, and a handle assembly at the proximal end of the elongate transmission guide having an input lever and a handle mechanism coupling the input lever to the transmission cable, wherein the transmission cable is coupled to a jaw input of the jaw assembly, wherein the jaw assembly is distal to the elongate transmission guide.
• the method may include: actuating the input lever to apply tension to the transmission cable during a first part of an input stroke of the handle assembly to close a first and second jaw of the jaw assembly from an open configuration until the first and second jaws reach a hard stop; and continuing to actuate the input lever during a second part of the input stroke after the first and second jaws have reached the hard stop and stretching the transmission cable; wherein the input stroke consists of a full displacement of the handle lever of the handle assembly, and further wherein the handle assembly transitions from the first part of the input stroke to the second part of the input stroke when the handle is between 30% and 70% displaced.
• a method of operating a medical device to close a jaw assembly of the medical device wherein the medical device comprises an elongate transmission guide, a finite stiffness transmission cable within the transmission guide, and a handle assembly at the proximal end of the elongate transmission guide having an input lever and a handle mechanism coupling the input lever to the transmission cable, wherein the transmission cable is coupled to a jaw input of the jaw assembly, wherein the jaw assembly is distal to the elongate transmission guide, may include: actuating the input lever to actuate the transmission cable during a first part of an input stroke of the handle assembly and translate the transmission cable relative to the elongate shaft to close a first and second jaw of the jaw assembly from an open configuration until the first and second jaws reach a hard stop; and continuing to actuate the input lever and stretching the transmission cable without translating the first or second jaws during a second part of the input stroke after the first and second jaws have reached the hard stop; wherein the input stroke consists of a full displacement of the handle lever of the handle assembly,
• Any of these methods may include applying a first mechanical advantage during the first part of the input stroke and applying a second mechanical advantage that is greater than the first mechanical advantage during the second part of the input stroke. These methods may also include grasping an object between the first and second jaws, wherein the first and second jaws reach the hard stop when the object is secured between the first and second jaws. Any of these methods may also include locking the input lever in a fully closed position relative to a handle shell in the handle assembly.
• Any of these methods may also include releasing the input lever to transition the handle lever from the second part of the input stroke to the first part of the input stroke, reducing the tension on the transmission cable and reducing the stretch of the transmission cable before translating the transmission cable so that the first and second jaws open.
• Actuating the input lever may comprise squeezing the input lever.
• a medical device having a distal jaw assembly actuated by a transmission cable having a finite stiffness in the transmission direction and is compliant in bending may include: a tool frame comprising an elongate shaft and a forearm attachment region at a proximal end of the tool frame configured to couple with an arm attachment cuff; a handle assembly, the handle assembly comprising a handle shell configured to be gripped in a user's palm and an input lever on the handle shell, wherein the handle shell encloses a handle linkage coupling the input lever to the transmission cable through a handle output, further wherein the handle assembly has an input stroke consisting of a full closure displacement of the input lever from an undisplaced configuration to a fully displaced configuration, further wherein the input lever transitions from a first part of the input stroke to a second
• a medical device apparatus includes ajaw closure transmission as described above.
• the exemplary apparatus includes a tool frame 525, which includes a tool shaft 526 and a forearm attachment portion at the proximal end 527.
• a cuff (not shown) having a passage therethrough that is configured to hold a wrist or forearm of a user may be coupled to the forearm attachment portion; in some variations via a bearing between the forearm attachment portion of the frame and the cuff that is configured to slide or roll so that there is a roll rotational degree of freedom between the frame and the cuff about the tool axis.
• a proximal handle assembly may be connected to the tool frame by an input joint.
• the input joint may be configured to encode motion between the tool frame and the handle assembly, as shown in FIG. 10.
• the input joint includes a pair of transmission strips 533, 534 that connect to respective pivoting joints (not shown) in parallel to separately encode pitch and yaw rotations of the handle assembly.
• the output joint 583 (an end-effector articulation joint configured as ajaw assembly), as shown in FIG. 14, may be any of the multi-cluster joints described herein and is between the jaw assembly and the tool frame (e.g., tool shaft) receives transmission input (e.g., cables, not shown) from the output joint 533, 534 to articulate the jaw assembly.
• the handle assembly includes an ergonomic palm grip portion 501 (handle shell) that connects to the rotation dial 502.
• the handle assembly also includes a control (lever) 549 input (in this example, defining the end-effector jaw closure input 549) that is configured as a handle lever and acts as a rigid extension of the internal push rod.
• a transmission cable 566 connects to the shuttle and acts as a jaw closure actuation transmission member extending from the shuttle and through the tool shaft to the jaw assembly. This transmission cable may be enclosed by a protective and/or supporting sheath or cover or conduit, for some or entire portion of its length.
• the end-effector is a jaw assembly including a first (ground) end-effector portion, in this example, including a fixed jaw 569 to which a pivoting second end- effector portion (moving jaw 568) is attached.
• the transmission cable 566 may couple to the moving jaw at the end-effector closure output 577.
• the handle may rotate about first axis 51 1 referred to as handle articulated roll axis (axis 1 ), to cause the tool shaft to rotate in a third axis 515 referred to as the tool shaft roll axis (axis 3), in turn causing the end-effector to roll about a second axis, referred to as an end-effector articulated roll axis (axis 2).
• the rotation dial 502 as shown in FIG. 10 is rotated about axis 1 51 1 .
• the rotation leads to rotation of tool frame 525 via transmission strips 533, 534 (as they constrain rotation DoF), tool shaft 526 (about axis 3 515) and therefore, the end-effector (about axis 2 513).
• the outputjoint multi-cluster joint 583) and end-effector articulates via the output articulating joint.
• the center axis (axis 2) for end-effector is different from the axis 3, the shaft axis.
• the Intermediate Transmission Mechanism consist of but not limited to a cam mechanism that is seen in as seen in Fig. 3B.
• the Intermediate Transmission Mechanism could be a linkage, gear, cog etc.
• Stroke A the force is not being amplified through the Intermediate Transmission mechanism however at the transition from Stroke A to Stroke B the First Transmission Member jumps lifts off the Hub and rides a surface farther away from the cams center of ration, creating a force amplification from the First Transmission Member to the Second Transmission Member. This force amplification increases the mechanical advantage of the system.
• This mechanism is shown in the structure of the device in Fig. 3C.
• Transmission System invention is specifically embodied as a laparoscopic, endoscopic, or other minimally invasive surgical jaw closure device, it is understood that those skilled in the art can alternately translate the invention, without departing from the scope, to alternate embodiments for Transmission Systems such as those that require end-effector clamping action like grasping, holding, or clamping instruments.
• FIG. 1 shows an example of a system diagram for an example of a jaw closure transmission system consisting of an Input Sub-System, a Flexible Transmission Sub-System and an Output Sub-System.
• FIG. 2 is another example of a diagram showing an example of a jaw closure transmission system consisting of an Input Sub-System, a Rigid Transmission Sub-System and an Output Sub-System.
• FIG. 3 is another example of a diagram showing an example of a jaw closure transmission systems with an intermediate transmission mechanism incorporated into the jaw closure transmission systems.
• Fig. 3B shows a physical embodiment of Intermediate Transmission Cam used to create a force amplification from the First Transmission Member to the Second Transmission Member.
• Fig. 3C shows a physical embodiment of Intermediate Transmission Mechanism located inside a device/ tool.
• FIG. 4 shows various needle cross sections that are commonly used in minimally invasive surgery and may be grasped by an apparatus including any of the jaw closure transmission systems described herein.
• FIG. 5 illustrates various needle geometries that are commonly used in minimally invasive surgery.
• FIG. 6 shows various needle sizes that are commonly used in minimally invasive surgery.
• FIG. 7 is a front view of Needle Driver Jaws Clamping down on a curved needle.
• FIG. 8 shows graphs illustrating the Transmission System of a Needle Driver's Input Stroke.
• FIG. 9 shows a mechanical advantage profile for the entire system as a function of the input handle lever displacement.
• FIG. 10 illustrates one example of a medical device incorporating a jaw closure transmission system as described herein.
• Fig. 1 1 shows an exploded view of the end effector assembly.
• Fig. 12A shows a detailed view of end effector assembly where the moveable jaw is in open condition.
• Fig. 1 2B shows a detailed view of end effector assembly where the moveable jaw is grasping a needle.
• Fig. 13 shows an input sub-system comprising a cam in the handle mechanism.
• Fig. 14 shows an embodiment of end-effector assembly including the output articulation joint.
• Fig. 15 show embodiment of a minimally invasive surgical device that incorporates jaw closure transmission system described here.
• Fig. 16 shows embodiments of a minimally invasive surgical device that incorporates jaw closure transmission system described here.
• jaw closure transmission systems and apparatuses including them.
• transmission system for a remote access tool which incorporates a transmission member with finite transmission direction stiffness (or equivalently, a compliant transmission member) that interfaces with the input and output mechanisms.
• a relatively stiff transmission member of a previous medical device can't be replaced with a compliant transmission member and achieve the performance described herein.
• the transmission system in its entirety must be designed in unison to achieve the performance that will be described.
• the performance of the transmission system in its current configuration is specific for a needle driver.
• Surgical needle drivers are one hand operation devices which require high clamping loads at jaw clamping surfaces in order to drive various needles through tissues.
• Fig.4 has various needle types that are selected based on the medium that they are driven through.
• the body of the needle is just an important as the tip in that as the needle is driven through the tissue there is an interaction between the needle in its entirety and the tissue.
• the jaws of a needle driver are designed with a pattern intended to increase the needle retention without requiring high jaw clamping loads. However, if a large enough clamping load is applied to the needle the clamping surfaces will damage the needle body, leaving permanent impressions on the need surface. When the surface of the needle is damaged it will no longer slide smoothly through the tissues which will result in resistance to surgeon and unnecessary damage to the patient.
• Fig.5 and Fig.6 respectively.
• the Jaws of the needle driver are designed to be wide enough to not allow the needle to rotate as a result needles with a larger curve and smaller diameter can be easily deformed and straighten out by large clamping loaded.
• Fig.7 showed a curved needle being held by the upper and lower jaws of a needle driver and as a larger clamping load is applied, the needle would straighten in that region due to three-point bending, causing the needle to not drive through the tissue in a true arc.
• the needle location in the jaws also influences the corresponding jaw clamping force and impacts ability to adequately secure a needle.
• the needle can be placed anywhere along thejaw length which could mean at the very tip of the jaws or at the mouth of the jaws, this significantly changes the effort required by the user to actuate the input mechanism completely to full stroke. In some configurations full stroke should not be achieved due to potential damaging the needle therefore typical needle drivers incorporate input ratcheting system, where the stroke of the handle can be broken up into finite segments in between ratchets to allow the user to hold the needle at various input lever locations.
• a compliant transmission member acts as an energy storage member so that the user can actuate the input handle lever completely with having to worry about over driving the jaws and damaging the needle. If a large needle is placed within the mouth of the jaws and full stroke can still be achieved at the handle input lever while in a needle driver with a stiff transmission member full stroke would not be achievable without causing damage to the instrument or the needle. This reduces the need for a multiple ratchet system which can provide discrepancies to users on whether adequate jaw clamping force is achieved.
• Stroke can be broken up into two different phases, Stoke A and Stroke B. Whereas the transition from Stroke A to Stroke B occur when the jaws reach a hard stop such that Stroke A is pre jaw hard stop and Stroke B being post Jaw hard stop. Jaw hard stop could occur at various handle lever displacements depending on the needle type, needle location or even needle presence.
• Fig.8 below shows various graphs that help explain what happens in the system as a fully input stroke is achieved.
• FIG. 8 Graph 1 shows the handle output, the profile of this curve is achieved through the geometry of the handle mechanism.
• This graph indirectly shows the mechanical advantage and the transmission ratio of the handle mechanism.
• This profile is extremely important as it is a non-constant mechanical advantage which consist of a low mechanical advantage at the beginning of the input stroke and then increases the mechanical advantage towards the end of the stroke. Due to ergonomic reasons (or limits), the limit of input displacement and force at the handle varies throughout the lever stroke (through the range of angular displacement).
• a varying mechanical advantage in the system means that during Stroke A can have a completely different transmission ratio than in Stroke B.
• Stroke A the jaws are freely rotating in space therefore a high transmission ratio and low mechanical advantage can be implemented into the design during this phase which enables the jaws to achieve a wide opening angle.
• Stroke B when the jaws reach a hard stop, a higher mechanical advantage is desired such that a large clamping load at the output can ergonomically be applied from the input.
• the system transmission ratio comes from two sources, the handle mechanism and the jaw mechanism.
• the jaw mechanism which is seen in FIG. 8 graph 2 has a similar mechanical advantage and transmission ratio curve as the handle mechanism, low mechanical advantage to start then high mechanical to end the stroke. However, the jaw mechanism has a different stroke than the input mechanism.
• the cable is stretched because the jaw mechanism is fixed at the distal end while the input handle mechanism is still able to produce more cable displacement as the handle input lever reaches a full displacement (full stroke).
• a system with a much stiffer transmission member such as steel rod or a flexible control wire will not perform in this manner as displacement at the input handle would be really hard to generate because the forces would directly relate to the clamping forces on the needle.
• a compliant transmission member allows for a soft buildup of force at the handle over a displacement to generate the closure force required.
• Stroke A the force felt at the handle input is the handle return spring which is shown in Fig.8 to have a linear spring constant K.
• Transmission member that is too compliant would mean inadequate clamping load while a Transmission member that is too stiff would require a ratcheting system and could damage the needle.
• references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.
• Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
• the singular forms "a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
• the device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms “upwardly”, “downwardly”, “vertical”, “horizontal” and the like are used herein for the potpose of explanation only unless specifically indicated otherwise.
• first and second may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.
• the word "comprise”, and variations such as “comprises” and “comprising” means various components can be conjointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods).
• the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.
• any of the apparatuses and methods described herein should be understood to be inclusive, but all or a subset of the components and/or steps may alternatively be exclusive, and may be expressed as “consisting of or alternatively “consisting essentially of the various components, steps, sub-components or sub-steps.
• a numeric value may have a value that is +/- 0.1 % of the stated value (or range of values), +/- 1 % of the stated value (or range of values), +/- 2% of the stated value (or range of values), +/- 5% of the stated value (or range of values), +/- 10% of the stated value (or range of values), etc.
• Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then “about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

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