# Patent

## Title
Simultaneous I-beam and spring driven cam jaw closure mechanism

## Abstract

A surgical instrument includes an end effector and a handle assembly. The end effector includes a movable jaw and a cutting element slidably movable within the end effector. The handle assembly includes an energy button configured to deliver energy to at least one electrode located in the end effector, a trigger plate operably coupled to a jaw closure mechanism, the trigger plate configured to close the movable jaw, a firing plate operably coupled to a cutting element drive mechanism. The firing plate is configured to drive the cutting element independently of the jaw closure mechanism. The cutting element drive mechanism is configured to close the movable jaw when the cutting element is driven. The handle assembly further includes a trigger operatively coupled to the trigger plate and the firing plate. The jaw closure mechanism and the cutting element drive mechanism are configured to simultaneously close the movable jaw.

## Background
The present disclosure is related generally to electrosurgical devices with various mechanisms for clamping and treating tissue. In particular, the present disclosure is related to electrosurgical devices with simultaneous I-beam and spring driven cam jaw closure mechanism.
Conventional electrosurgical devices have poor grasping and cannot seal without cutting. These issues are due to the fact that the I-beam closes the jaws. Due to component tolerances it is almost impossible to make a set of large jaws that can be closed with an I-beam where the jaws will come fully together with the I-beam closing from the rear of the jaws. The I-beam, however, has lots of advantages on sealing thick and diseased tissue. So, a solution is needed that allows for improved grasping and sealing without cutting, but also allows the jaws to be closed with an I-beam.
While several devices have been made and used, it is believed that no one prior to the inventors has made or used the device described in the appended claims.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. patent application Ser. No. 14/468,037, titled “LOCKOUT DISABLING MECHANISM,” filed Aug. 25, 2014, now U.S. Pub. No. 2016/0051317 and U.S. patent application Ser. No. 14/467,990, titled “ELECTROSURGICAL ELECTRODE MECHANISM,” filed Aug. 25, 2014, now U.S. Pub. No. 2016/0051316; each of which is incorporated herein by reference in its entirety.
SUMMARY
In one embodiment, a surgical instrument is provided. The surgical instrument comprises an end effector and a handle assembly. The end effector comprises a movable jaw; and a cutting element slidably movable within the end effector. The handle assembly comprises an energy button configured to deliver energy to at least one electrode located in the end effector; a trigger plate operably coupled to a jaw closure mechanism. The trigger plate configured to close the movable jaw; a firing plate operably coupled to a cutting element drive mechanism. The firing plate is configured to drive the cutting element independently of the jaw closure mechanism. The cutting element drive mechanism is configured to close the movable jaw when the cutting element is driven. The handle assembly also comprises a trigger operatively coupled to the trigger plate and the firing plate. The jaw closure mechanism and the cutting element drive mechanism are configured to simultaneously close the movable jaw.
In another embodiment, the surgical instrument comprises a spring located inline with the jaw closure mechanism, wherein the jaw closure mechanism is configured to close the jaw ahead of the cutting element drive system until a force required to close the movable jaw overcomes a force generated by the spring at which time the cutting element drive mechanism overtakes the jaw closure mechanism to close the movable jaw. In another embodiment, the spring can be pre-compressed to increase the starting load. In another embodiment, the jaw closure mechanism comprises a spring, a closure bar coupled to the spring, and a pivoting link having a proximal end and a distal end, the proximal end coupled to the closure bar and the distal end coupled to the movable jaw. In another embodiment, the surgical instrument comprises a closure actuator coupled to the spring and coupled to the trigger plate via a toggle clamp, wherein the closure actuator is configured to compress the spring.
In another embodiment, the cutting element drive mechanism comprises a firing bar having a proximal end and a distal end, a cutting element coupled to the distal end of the firing bar, a rack coupled to the proximal end of the firing bar, wherein the rack is operatively coupled to the firing plate.
In another embodiment, the surgical instrument comprises a lockout disabling mechanism comprising a lock arm operatively coupled to a lever arm and a lockout element, wherein the lockout element is configured to prevent the cutting element drive mechanism from driving a cutting element.
In one embodiment, a surgical instrument is provided. The surgical instrument comprises an end effector comprising a movable jaw, a cutting element slidably movable within the end effector, a jaw closure mechanism configured to close the movable jaw via a spring driven cam system, and a cutting element drive mechanism configured to drive the cutting element independently of the jaw closure mechanism. The cutting element drive system comprises an I-beam member. The cutting element drive mechanism is configured to close the movable jaw when the cutting element is driven. The jaw closure mechanism and the cutting element drive mechanism are configured to simultaneously close the movable jaw.
In another embodiment, the jaw closure mechanism is configured to close the jaw ahead of the cutting element drive system until a force required to close the movable jaw overcomes a force generated by the spring at which time the cutting element drive mechanism overtakes the jaw closure mechanism to close the movable jaw.
In another embodiment, the spring can be pre-compressed to increase the starting load.
In another embodiment the jaw closure mechanism comprises a closure bar coupled to the spring and a pivoting link having a proximal end and a distal end, the proximal end coupled to the closure bar and the distal end coupled to the movable jaw.
In another embodiment, the surgical instrument comprises a closure actuator having a proximal end and a distal end, the distal end coupled to the spring and the proximal end coupled to a toggle clamp configured to drive the closure actuator. The closure actuator is configured to compress the spring when the closure actuator moves in a distal direction.
In another embodiment, the cutting element drive mechanism comprises a firing bar having a proximal end and a distal end, a cutting element coupled to the distal end of the firing bar, and a rack coupled to the proximal end of the firing bar. The rack is operatively coupled to the firing plate.
In another embodiment, the surgical instrument comprises a lockout disabling mechanism comprising a lock arm operatively coupled to a lever arm and a lockout element. The lockout element is configured to prevent the cutting element drive mechanism from driving a cutting element.
In one embodiment, a surgical instrument is provided. The surgical instrument comprises a handle assembly, a shaft assembly, and an end effector. The handle assembly comprises a trigger operatively coupled to a trigger plate and a firing plate, an energy button configured to deliver energy to at least one electrode, a lockout element operatively coupled to the energy button. The lockout element is configured to prevent operation of the firing plate. The handle assembly also comprises a lockout disabling mechanism configured to disable the lockout element. The lockout disabling mechanism is operable between a first position and a second position. When the lockout disabling mechanism is located in the first position, the lockout element is enabled and can be unlocked by the energy button, and wherein when the lockout disabling mechanism is in the second position, the lockout element is disabled. The shaft assembly comprises a proximal end and a distal end. The shaft assembly is coupled to the handle assembly at the proximal end. The end effector is coupled to the distal end of the shaft assembly. The end effector comprises a jaw assembly, comprising a first jaw member and a second jaw member. The rotation of the trigger plate transitions the jaw assembly between an open configuration and an approximated configuration by moving at least one of the first jaw member and the second jaw member relative to the other one of the first jaw member and the second jaw member. The end effector also comprises a cutting element deployable in response to rotation of the firing plate, a jaw closure mechanism configured to close the movable jaw via a spring driven cam system, and a cutting element drive mechanism configured to drive the cutting element independently of the jaw closure mechanism. The cutting element drive system comprises an I-beam member. The cutting element drive mechanism is configured to close the movable jaw when the cutting element is driven. The jaw closure mechanism and the cutting element drive mechanism are configured to simultaneously close the at least one of the first jaw member and the second jaw member.
In another embodiment, the jaw closure mechanism is configured to close the jaw ahead of the cutting element drive system until a force required to close the at least one of the first jaw member and the second jaw member overcomes a force generated by the spring at which time the cutting element drive mechanism overtakes the jaw closure mechanism to close the at least one of the first jaw member and the second jaw member.
In another embodiment, the spring can be pre-compressed to increase the starting load.
In another embodiment, the jaw closure mechanism comprises a closure bar coupled to the spring and a pivoting link having a proximal end and a distal end, the proximal end coupled to the closure bar and the distal end coupled to the at least one of the first jaw member and the second jaw member.
In another embodiment, the surgical instrument comprises a closure actuator having a proximal end and a distal end, the distal end coupled to the spring and the proximal end coupled to a toggle clamp configured to drive the closure actuator, wherein the closure actuator is configured to compress the spring when the closure actuator moves in a distal direction.
In another embodiment, the cutting element drive mechanism comprises a firing bar having a proximal end and a distal end a cutting element coupled to the distal end of the firing bar and a rack coupled to the proximal end of the firing bar. The rack is operatively coupled to the firing plate.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.



FIGURES
The novel features of the embodiments described herein are set forth with particularity in the appended claims. The embodiments, however, both as to organization and methods of operation may be better understood by reference to the following description, taken in conjunction with the accompanying drawings as follows.
FIG. 1 illustrates a surgical instrument comprising a knife lockout disabling mechanism, according to one embodiment.
FIG. 2 is a perspective view of a handle assembly of the surgical instrument illustrated in FIG. 1 with the left handle housing shroud and several sheaths in the shaft assembly removed, according to one embodiment.
FIG. 3 is a side elevation view of a handle assembly of a surgical instrument, similar to the surgical instrument shown in FIGS. 1 and 2, with the left handle housing shroud removed, and without the lockout disabling mechanism, according to one embodiment.
FIG. 4 is an exploded view of the shaft assembly, end effector, yoke, and rack portions of the surgical instrument shown in FIGS. 1 and 2, according to one embodiment.
FIG. 5 is a perspective view of the shaft assembly, end effector, yoke, and rack shown in FIG. 4 in the assembled state, according to one embodiment.
FIG. 6 is a perspective view of the shaft assembly, end effector, yoke, and rack shown in FIG. 5, according to one embodiment, with the electrically insulative nonconductive tube removed to show the functional components of the shaft assembly in the assembled state.
FIG. 7 is a sectional view taken along a longitudinal axis of the shaft assembly, yoke, and rack shown in FIG. 5, according to one embodiment, to show the functional components of the shaft assembly in the assembled state.
FIG. 8 is partial perspective view of the shaft assembly shown in FIG. 7, according to one embodiment.
FIG. 9 is a side view of an end effector portion of the surgical instrument shown in FIGS. 1 and 2 with the jaws open, according to one embodiment.
FIG. 10 shows the closure bar and I-beam member at the initial stage of clamp closure and firing sequence where the I-beam member is located at the base of a ramp in the upper jaw, according to one embodiment.
FIG. 11 shows the closure bar and I-beam member further advanced distally than shown in FIG. 10, where the I-beam member is located at an intermediate position along the ramp in the upper jaw, according to one embodiment.
FIG. 12 shows the closure bar and I-beam member further advanced distally than shown in FIG. 11 where the I-beam member is located at the top of the ramp in the upper jaw, according to one embodiment.
FIG. 13 shows the closure bar and I-beam member further advanced distally than shown in FIG. 12, where the I-beam member is located past the ramp in the upper jaw, according to one embodiment.
FIG. 14 is a side elevational view of the surgical instrument shown in FIGS. 1 and 2 with the left housing shroud removed, shaft assembly sheaths removed, and the jaw fully open, according to one embodiment.
FIG. 15 is a perspective view of the surgical instrument shown in FIG. 14 with the right housing shroud removed, according to one embodiment.
FIG. 16 is another perspective view of the surgical instrument shown in FIG. 15, according to one embodiment.
FIG. 17 is a side elevational view of the surgical instrument shown in FIG. 14 with the right housing shroud removed, according to one embodiment.
FIG. 18 is a side elevational view of the surgical instrument shown in FIG. 14 with the firing plate removed, according to one embodiment.
FIG. 19 is a side elevational view of the surgical instrument shown in FIG. 18 with the lockout defeat mechanism slider removed, according to one embodiment.
FIG. 20 is a side elevational view of the surgical instrument shown in FIG. 18 with the toggle clamp and yoke removed, according to one embodiment.
FIG. 21 is a partial perspective view of the surgical instrument shown in FIG. 20, according to one embodiment.
FIG. 22 is a partial perspective view of the surgical instrument shown in FIG. 21 with the firing plate replaced, according to one embodiment.
FIG. 23 is a partial perspective view of the surgical instrument shown in FIG. 22 with the lockout defeat mechanism slider, lever arm, and lock arm removed, according to one embodiment.
FIG. 24 is a side elevational view of the surgical instrument shown in FIGS. 1 and 2 with the left and right housing shrouds removed, shaft assembly sheaths removed, jaws clamped, and the lockout defeat mechanism enabled, e.g., in the “ON” position, according to one embodiment.
FIG. 25 is a side elevational view of the surgical instrument shown in FIGS. 1 and 2 with the left and right housing shrouds removed, shaft assembly sheaths removed, jaws fully closed, knife fully fired, and the lockout defeat mechanism disabled, e.g., in the “OFF” position, according to one embodiment.
FIG. 26 is a side elevational view of the surgical instrument shown in FIGS. 1 and 2 with the left and right housing shrouds removed, shaft assembly sheaths removed, jaws fully open, knife not fired, and the lockout defeat mechanism disabled, e.g., in the “OFF” position, according to one embodiment.



DESCRIPTION
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols and reference characters typically identify similar components throughout the several views, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the scope of the subject matter presented here.
The following description of certain examples of the technology should not be used to limit its scope. Other examples, features, aspects, embodiments, and advantages of the technology will become apparent to those skilled in the art from the following description, which is by way of illustration, one of the best modes contemplated for carrying out the technology. As will be realized, the technology described herein is capable of other different and obvious aspects, all without departing from the technology. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.
It is further understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. that are described herein. The following-described teachings, expressions, embodiments, examples, etc. should therefore not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined will be readily apparent to those of ordinary skill in the art in view of the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.
Before explaining the various embodiments of the surgical devices having a closure system comprising an I-beam and spring driven cam system to simultaneously close a set of opposing jaws in detail, it should be noted that the various embodiments disclosed herein are not limited in their application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. Rather, the disclosed embodiments may be positioned or incorporated in other embodiments, variations and modifications thereof, and may be practiced or carried out in various ways. Accordingly, embodiments of the surgical devices disclosed herein are illustrative in nature and are not meant to limit the scope or application thereof. Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the embodiments for the convenience of the reader and are not to limit the scope thereof. In addition, it should be understood that any one or more of the disclosed embodiments, expressions of embodiments, and/or examples thereof, can be combined with any one or more of the other disclosed embodiments, expressions of embodiments, and/or examples thereof, without limitation.
Also, in the following description, it is to be understood that terms such as front, back, inside, outside, top, bottom and the like are words of convenience and are not to be construed as limiting terms. Terminology used herein is not meant to be limiting insofar as devices described herein, or portions thereof, may be attached or utilized in other orientations. The various embodiments will be described in more detail with reference to the drawings.
In various embodiments, the present disclosure provides an electrosurgical instrument having a closure system comprising an I-beam and spring driven cam system to simultaneously close a set of opposing jaws. In order to grasp better a separate mechanism is provided to close the jaws independently of the I-beam drive. To ensure the I-beam will also be able to close the jaws the separate mechanism operates in tandem with the I-beam drive. In one embodiment, a cam closure that closes the jaws and moves along with the I-beam is provided. Some conventional electrosurgical devices employ a toggle clamp to move the I-beam to close the jaws. A separate closure system can be attached to the toggle clamp alongside the I-beam so that they both move at the same time. The cam closure can be timed to close the jaws before the I-beam. The cam system also can incorporate an inline spring. This spring can compress at the end of the closure stroke to keep the jaws shut with a set spring force. If material in the jaws forces the spring to compress too much on the cam closure then the I-beam can take over to close the jaws. Accordingly, in this system the I-beam will ensure the jaws always fully close the jaws with the toggle clamp. The I-beam is configured to only close the jaws when the material in the jaws takes more force to close than the cam spring can provide. The cam system also can have a rising mechanical advantage as the jaw is closed such that the further the spring is compressed the less force is exerted on the jaws. This prevents damaging tissue from too much spring force.
In one embodiment, the closure system comprising an I-beam and spring driven cam system to simultaneously close a set of opposing jaws can be configured to operate in the following manner: (1) place tissue in the jaws and pull the trigger; (2) the toggle clamp pushes on the I-beam and the cam closure; (3) the cam immediately pushes on the jaw through a spring to close it, the I-beam trails a closure ramp on the upper jaw; (4) the cam fully closes the jaws before the toggle stops moving; (5) the toggle clamp continues to move (e.g., another 0.05 inches) to compress the closure spring to ensure the jaws are sprung closed, the I-beam moves over the top of the ramp; and (6) thick tissue in the jaws may compress the spring on the cam closure before the end of the toggle stroke, the I-beam will hit the closure ramp and force the jaws closed to ensure that the I-beam will repeatedly be located over the ramp with the jaws closed before the toggle stops moving.
The closure system comprising an I-beam and spring cam driven cam system is configured to simultaneously close a set of opposing jaws provides several advantages over conventional devices. The disclosed device can seal tissue without necessarily cutting the tissue, provides improved tissue grasping, ensures that the I-beam is located over the ramp before a gear train in the jaw device takes over to provide lower force to fire. The disclosed closure system also provides improved jaw opening and tissue dissection over conventional devices. The disclosed closure system also provides lower force to fire from preload on tissue. The gears fire the I-beam forward and can be configured to operate with conventional electrosurgical jaw designs. Additional advantages, not necessarily described herein, are also provided.
In various embodiments, the present disclosure provides an electrosurgical radio frequency (RF) bipolar sealing device comprising an I-beam and spring driven cam system to simultaneously close a set of opposing jaws. The spring driven cam closure system can close the jaws first unless the force to close the jaws overcomes the spring, at this point the I-beam will close the jaws. The cam system composes a spring connected to a bar, which is in turn connected to a pivoting link, which is then connected to a jaw. Pushing on the spring pushes on the bar which pushes on the link which closes the jaw. The spring on the cam closure system can be pre-compressed to raise its starting load.
Turning now to the figures, FIG. 1 illustrates a surgical instrument 102 comprising a trigger assembly 107 and a closure system arrangement for closing the jaws 110 comprising a separate spring driven cam closure mechanism that is independent of the I-beam closure mechanism. The spring driven cam closure system and the I-beam closure system are configured to independently close a set of opposing jaws 116a, 116b, and independently fire a cutting element in the end effector 110. The trigger assembly 107 is configured to clamp and independently fire an end effector 110 coupled to the shaft assembly 112 of the surgical instrument 102. In the embodiment shown in FIG. 1, the surgical instrument comprises a trigger assembly 107 and a lockout disabling mechanism 108. In this view, a first jaw member 116a of an end effector 110 is fully open and the knife lockout disabling mechanism 108 is located in the off position. The knife lockout disabling mechanism 108 is configured to clamp and fire an end effector 110 coupled to the surgical instrument 102. The surgical instrument 102 comprises a handle assembly 104, a shaft assembly 112, and the end effector 110. The shaft assembly 112 comprises a proximal end and a distal end. The proximal end of the shaft assembly 112 is coupled to the distal end of the handle assembly 104. The end effector 110 is coupled to the distal end of the shaft assembly 112. The handle assembly 104 comprises a pistol grip 118. The handle assembly 104 comprises a left handle housing shroud 106a and a right handle housing shroud 106b. The trigger assembly 107 comprises a trigger 109 actuatable towards the pistol grip 118. The knife lockout disabling mechanism 108 comprises a button 139, or knob, that is actuatable for adjusting or controlling the position of the knife lockout disabling mechanism 108 between first and second positions A and B (A=Distal and B=Proximal relative to the clinician) within a slot 111 formed in the left handle housing shroud 106a. A rotatable shaft knob 120 is configured to rotate the shaft assembly 112 with respect to the handle assembly 104. The handle assembly 104 further comprises an energy button 122 configured to provide electrosurgical energy to one or more electrodes in the end effector 110.
The knife lockout mechanism forces the user to first clamp (close the jaws 110), energize the electrodes, then cut the tissue (fire the knife). The knife unlock feature contains the energy button 122 so that the energy button 122 has to be depressed before the knife can be released or that the single trigger can move the rack 136 forward. The single trigger 109 closes the jaws in the first  ̃13 degrees of stroke. The single trigger 109 fires the knife in the last  ̃29 degrees of stroke. The lockout is the stop in between the first stroke and the second stroke. An energy switch (not shown) is located underneath the energy button 122 housing. Accordingly, the lock release mechanism also is the energy delivery element.
The shaft assembly 112 comprises a closure/jaw actuator, a firing/cutting member actuator, and an outer sheath. In some embodiments, the outer sheath comprises the closure actuator. The outer sheath comprises one or more contact electrodes on a distal end configured to interface with the end effector 110. The one or more contact electrodes are operatively coupled to the energy button 122 and an energy source (not shown).
The energy source may be suitable for therapeutic tissue treatment, tissue cauterization/sealing, as well as sub-therapeutic treatment and measurement. The energy button 122 controls the delivery of energy to the electrodes. As used throughout this disclosure, a button refers to a switch mechanism for controlling some aspect of a machine or a process. The buttons may be made out of a hard material such as usually plastic or metal. The surface may be formed or shaped to accommodate the human finger or hand, so as to be easily depressed or pushed. Buttons can be most often biased switches, even though many un-biased buttons (due to their physical nature) require a spring to return to their un-pushed state. Terms for the “pushing” of the button, may include press, depress, mash, and punch.
In some embodiments, an end effector 110 is coupled to the distal end of the shaft assembly 112. The end effector 110 comprises a first jaw member 116a and a second jaw member 116b. The first jaw member 116a is pivotally coupled to the second jaw member 116b. The first jaw member 116a is pivotally moveable with respect to the second jaw member 116b to grasp tissue therebetween. In some embodiments, the second jaw member 116b is fixed. In other embodiments, the first jaw member 116a and the second jaw member 116b are pivotally movable. The end effector 110 comprises at least one electrode. The electrode is configured to deliver energy. Energy delivered by the electrode may comprise, for example, radiofrequency (RF) energy, sub-therapeutic RF energy, ultrasonic energy, and/or other suitable forms of energy. In some embodiments, a cutting member (not shown) is receivable within a longitudinal slot defined by the first jaw member 116a and/or the second jaw member 116b. The cutting member is configured to cut tissue grasped between the first jaw member 116a and the second jaw member 116b. In some embodiments, the cutting member comprises an electrode for delivering energy, such as, for example, RF and/or ultrasonic energy.
In certain instances, as described above, the surgical instrument 102 may include an automatic energy lockout mechanism. The energy lockout mechanism can be associated with a closure mechanism of the surgical instrument 102. In certain instances, the energy lockout mechanism can be configured to permit energy delivery to the end effector 10 when the energy delivery button 122 is actuated if the jaw members 116a and 116b are in an open configuration. In certain instances, the energy lockout mechanism may be configured to deny energy delivery to the end effector 110 when the energy delivery button 122 is actuated if the jaw members 116a and 116b are in a closed configuration. In certain instances, the energy lockout mechanism automatically transitions from permitting the energy delivery to denying the energy delivery when the jaw members 116a and 116b are transitioned from the closed configuration to the open configuration, for example. In certain instances, the energy lockout mechanism automatically transitions from denying the energy delivery to permitting the energy delivery when the jaw members 116a and 116b are transitioned from the open configuration to the closed configuration, for example.
FIG. 2 is a perspective view of a handle assembly 104 of a surgical instrument 102 illustrated in FIG. 1, according to one embodiment, with the right housing shroud 106a and the outer and inner sheaths of the shaft assembly 112 removed to show some of the internal mechanisms. The left handle housing shroud 106b of the handle assembly 104 comprises the knife lockout disabling mechanism 108. The button 139 is located in the first “off” position A (A=distal relative to the clinician) within the slot 111 formed in the right handle housing shroud 106a. In the illustrated embodiment, position B (B=proximal relative to the clinician) corresponds to the second “on” position of the knife lockout disabling mechanism 108, where the knife lockout mechanism remains disabled until the button is switched back to position A. Accordingly, position A corresponds to the enabled state of the knife lockout mechanism and position B corresponds to the disabled state of the knife lockout mechanism. Stated differently, position A corresponds to the “off” state of the knife lockout disabling mechanism 108 and position B corresponds to the “on” state of the knife lockout disabling mechanism 108. When the knife lockout mechanism is in the disabled state, the energy button 122 may appear to be depressed to provide a visual indication to the clinician that the knife lockout mechanism has been disabled but without energizing the electrodes in the end effector 110 (FIG. 1). When the knife lockout mechanism is disabled, the knife may be fired at will without the need to apply electrosurgical energy to one or more electrodes in the end effector 110.
The trigger assembly 107 comprises the necessary components for closing the jaw members 116a, 116b and firing the cutting member or knife bands 174. The trigger assembly 107 comprises a trigger plate 124 and firing plate 128 operatively coupled to the trigger 109. Squeezing the trigger 109 in direction C towards the pistol grip 118 rotates the trigger plate 124 which operates the toggle clamp 145 to advance a yoke 132 and a closure actuator 129 distally to close the jaw members 116a, 116b of the end effector. Initial rotation of the trigger plate 124 also slightly rotates the firing plate 128. The firing plate 128 comprises a sector gear with a plurality of teeth 131 that engage and rotate a first pinion gear 133, which engages a second pinion gear 134 to advance a rack 136 (neither is shown in this view). A lock arm 157 (shown in FIGS. 21-22, for example) is operatively coupled to a lever arm 115, an unlock arm 119, and a lockout element 165. When the instrument 102 is in normal lockout mode, the lock arm 157 engages a notch 158 (shown in FIGS. 4 and 21-23, for example) in the rack 136 to lock the rack 136 and prevent the rack 136 from moving distally (firing) no matter how hard the trigger 109 is squeezed.
The single trigger 109 closes the jaws in the first  ̃13 degrees of stroke. The trigger plate 124 is configured to interface with the trigger plate 124 during rotation of the trigger 109 from an initial position to a first rotation, which is  ̃13 degrees of stroke, for example. The trigger plate 124 is operably coupled to the firing plate 128. In certain instances, the firing plate 128 may include a first slot 128a and a second slot 128b. The first slot 128a receives a drive pin 148 fixedly coupled to the trigger plate 124. The pin 148 slidably moves within the first slot 128a. Rotation of the trigger plate 124, while the pin 148 is slidably received within the first slot 128a, drives rotation of the firing plate 128. The teeth 131 of the sector gear engage and rotate the first pinion 133, which in turn drives the second pinion 134, which drives the rack 136 distally to fire the cutting element, or knife, but only when the knife lockout is unlocked, released, or disabled.
The single trigger 109 fires the knife in the last  ̃29 degrees of stroke. Rotation of the trigger plate 124 beyond a predetermined rotation such as, for example, the first rotation, causes rotation of the firing plate 128. Rotation of the firing plate 128 deploys a cutting member within the end effector 110. For example, in the illustrated embodiment, the firing plate 128 comprises a sector gear operably coupled to a rack 136 through the first and second pinions 133, 134. The firing plate 128 comprises a plurality of teeth 131 configured to interface with the first pinion 133. Rotation of the firing plate 128 rotates the first and second pinions 133, 134, to drive the rack 136 distally. Distal movement of the rack 136 drives the cutting member actuator distally, causing deployment of the cutting member (e.g., knife) within the end effector 110.
The lockout is the stop in between the first stroke and the second stroke. Turning back now to the description of the lockout disabling mechanism 108, when the slider 113 button 139 portion is in located in position A, the lock arm 157 cam be released by pressing or actuating the energy button 122 to rotate the lockout element 165, which rotates the unlock arm 119 to release the lock arm 157. Once the lock arm 157 is released, the rack 136 is enabled to advance distally and fire the knife by squeezing the trigger 109 in direction C further towards the pistol grip 118. As the trigger 109 is squeezed, the firing plate 128 rotates and drives the first pinion gear 133, which drives the second pinion gear 134 to drive the rack 136.
When the button 139 is located in position B, the slider 113 rotates the lever arm 115, which rotates the unlock arm 119 to releases the lock arm 157. While the button 139 is in position B, the rack 136 can be fired without the need to press energy button 122 to rotate the lockout element 165. A detent may be provided to hold the button in either position A or B. These and other features are described in more detail hereinbelow.
The shaft assembly 112 comprises a closure/jaw actuator and a firing/cutting member actuator. The closure/jaw actuator comprises a yoke 132 and toggle clamp 145 assembly operatively coupled to a closure actuator 129 which acts on a closure spring 114 coupled to a spring-to-bar interface element 127 and a closure bar 142. In one instance the closure bar 142 is operatively coupled to the jaw members 116a, 116b via at least one linkage. The firing/cutting member actuator comprises a rack 136 operatively coupled to a firing bar 117, which is slidably received within the closure actuator 129 and the closure spring 114. The firing bar 117 is coupled to a knife pusher block 140 and a flexible I-beam knife band 174 comprising multiple flexible bands fastened together and a cutting element at the distal end. Advancing the rack 136 in the distal direction advances the cutting element band 174 distally through a channel or slot formed in the jaw members 116a, 116b. 
FIG. 3 is a side elevation view of a handle assembly 104 of a surgical instrument 101, with the left handle housing shroud 106a removed to expose various mechanisms located within the handle assembly 104 and without the knife lockout disabling mechanism 108, according to one embodiment. Except for the knife lockout disabling mechanism, in other aspects, the surgical instrument 101 operates in a manner similar to the surgical instrument described in connection with FIGS. 1 and 2.
FIG. 4 is an exploded view of the shaft assembly 112, end effector 110, yoke 132, and rack 136 portions of the surgical instrument 102 shown in FIGS. 1 and 2, according to one embodiment. FIG. 5 is a perspective view of the shaft assembly 112, end effector 110, yoke 132, and rack 136 shown in FIG. 4 in the assembled state, according to one embodiment. FIG. 6 is a perspective view of the shaft assembly 112, end effector 110, yoke 132, and rack 136 shown in FIG. 5, according to one embodiment, with the electrically insulative nonconductive tube 176 removed to show the functional components of the shaft assembly 112 in the assembled state. FIG. 7 is a sectional view taken along a longitudinal axis of the shaft assembly 112, yoke 132, and rack 136 shown in FIG. 5, according to one embodiment, to show the functional components of the shaft assembly 112 in the assembled state. FIG. 8 is partial perspective view of the shaft assembly 112 shown in FIG. 7, according to one embodiment.
With reference now to FIGS. 4-7, the shaft assembly 112 comprises an outer tube 100 which contains or houses the various functional components of the shaft assembly 112. An electrically insulative nonconductive tube 176 is slidably received within the outer tube 100. A clamp tube 161 is attached to the nonconductive tube 176. The functional components of the shaft assembly 112 are slidably contained within the within the nonconductive tube 176 whereas the conductive elements 107a, 107b employed to supply electrical energy to the end effector 110 electrodes 135 are located outside the nonconductive tube 176. A closure actuator 129 is coupled to the distal end of the yoke 132. The closure actuator 129 comprises a proximal portion and a distal portion. The distal portion of the closure actuator 129 is sized to be received within a closure spring 114. The proximal portion of the closure actuator 129 is sized to compress the closure spring 114. The closure spring 114 is coupled to a closure bar 142 through a spring to bar interface element 127. The distal end 172 of the closure bar 142 is operatively coupled to the jaws 116a, 116b by a pin 180 and closure linkages 178a, 178b. The jaws 116a, 116b are pivotally coupled by a pin 182 and rotatable support structures 146a, 146b formed in the top jaw 116a. The closure actuator 129 is coupled to the distal end of the yoke 132, which is operatively coupled to the toggle clamp 145 (FIGS. 1-3, for example). As previously described, the toggle clamp 145 is movably coupled to the trigger plate 124 (FIGS. 1-3), for example. Rotation of the trigger plate 124 straightens the toggle clamp 145 to drive the yoke 132 distally. Distal movement of the yoke 132 causes distal movement of the closure actuator 129 to compress the closure spring 114 and drive the closure bar 142. Distal movement of the closure actuator 129 pivotally moves the first jaw member 116a from an open position to a closed position with respect to the second jaw member 116b, for example.
A firing bar 117 comprises a proximal end 117a and a distal end 117b. The proximal end 117a of the firing bar 117 is coupled to the distal end 130 of the rack 136. The rack 136 is received within the yoke 132. The firing bar 117 is received within the closure actuator 129, the spring to bar interface element 127, and the jaw open spring 138. The distal end 117b of the firing bar 117 is fixedly coupled to a knife pusher block 140, which is fixedly coupled to a cutting element 174 (knife). The cutting element 174 comprises flexible bands 174a, 174b, 174c, which are fastened by the knife pusher block 140 at the proximal end and by pins 144a, 144b at the distal end to form knife or cutting element having an I-beam configuration. As previously described, the teeth 131 of the sector gear of the firing plate 128 engage and rotate the pinions 133, 134, which drive the rack 136 distally. The rack 136 drives the firing bar 117, which in turn drives the flexible I-beam cutting element 174 when the lock arm 157 is disengaged from a notch 158 formed in the rack 136.
FIG. 9 is a side view of an end effector 110 portion of the surgical instrument 102 shown in FIGS. 1 and 2 with the jaws open, according to one embodiment. The closure bar 142 is operatively coupled to the proximal end of the top jaw 116 a via the closure linkages 178 a, 178 b (not shown) and first and second pins 180 a, 180 b. The lower pin 180 a is slidably movable within a slot 212. As the closure bar 142 moves distally in the direction indicated by arrow AA, the pin 180 a slides in the slot 212 to and forces the second pin 180 b to move upwardly in the direction indicated by arrow BB to force the top jaw 116 a to rotate to a closed position as indicated by arrow CC. The top jaw 116 a pivots about a pivot point defined by the fastener pin 182. The bottom jaw 116 b comprises the electrode 135, which is electrically coupled to an energy source (e.g., an RF electrosurgical energy source). The flexible I-beam band knife comprises a knife or cutting element 174. The cutting element 174 and the fastener pins 144 a, 144 b form an I-beam member 216 that forces the jaws 116 a, 116 b shut when the cutting element 174 is fired by the rack 136 and firing bar 117, as previously described. The I-beam member 216 advances distally on tracks 210 a, 210 b formed in the respective upper and lower jaws 116 a, 116 b to force the jaws 116 a, 116 b shut and compress the tissue located therebetween. A ramp 204 is defined at the proximal end of the top track 210 a in the top jaw 116 a. Accordingly, a predetermined force is required to advance the I-beam member 216 over the ramp 204 before the I-beam member 216 engages the top track 210 a to close the jaws 116 a, 16 b as the I-beam member 216 is advanced distally by the flexible I-beam band 174. In the present view, the I-beam member 216 is located behind the ramp 204 as the linkages 178 a, 178 b (not shown) close the jaws 116 a, 116 b. 
FIGS. 10-13 illustrate a sequence of firing the I-beam member 216 and closure spring 114 driven cam system to simultaneously close a set of opposing jaws 116a, 116b. FIG. 10 shows the closure bar 142 and the I-beam member 216 at the initial stage of clamp closure and firing sequence where the I-beam member 216 is located behind or at the base of a ramp 204 in the upper jaw 116a, according to one embodiment. The pins 144a, 144b (not shown) of the I-beam member 216 are located at the base of the ramp 204 prior to firing the cutting element 174. In this view, the I-beam member 216 is located behind the ramp 204 as pivoting link 178a closes the upper jaw 116a in direction CC.
FIG. 11 shows the closure bar 142 and I-beam member 216 further advanced distally in direction AA than shown in FIG. 10, where the I-beam member 216 is located at an intermediate position along the ramp 204 in the upper jaw 116a, according to one embodiment. FIG. 11 shows the closure bar 142 pushing on the bottom pin 180a to move distally in direction AA within the slot 212. In response, the pivoting link 178a moves distally in direction AA and rotates counterclockwise pushing the top pin 180b upwardly in direction BB to apply a closing force to the upper jaw 116a. The I-beam member 216 also advances partially up the ramp 204. The upper jaw 116a rotates slightly in direction CC toward a closed position.
FIG. 12 shows the closure bar 142 and the I-beam member 216 further advanced distally in direction AA than shown in FIG. 11 where the I-beam member 216 is located at the top of the ramp 204 in the upper jaw 116a, according to one embodiment. In FIG. 12, the closure bar 142 is advanced further distally in direction AA in response to the closure actuator 129 acting on the closure spring 114 and continues pushing on the bottom pin 180a causing it to move further distally in direction AA within the slot 212. In response, the pivoting link 178a moves distally in direction AA and continues rotating counterclockwise pushing the top pin 180b upwardly in direction BB to apply a closing force to the upper jaw 116a. The upper jaw 116a continues rotating further in direction CC toward a closed position. At this stage, the I-beam member 216 is located at the top of the ramp 204.
FIG. 13 shows the closure bar 142 and I-beam member 216 further advanced distally than shown in FIG. 12, where the I-beam member 216 is located past the ramp 204 in the upper jaw 116a, according to one embodiment. FIG. 13 shows the closure bar 142 advanced still further distally in direction AA and continues to push on the bottom pin 180a causing it to move distally in direction AA within the slot 212. In response, the pivoting link 178a moves distally in direction AA and continues rotating counterclockwise pushing the top pin 180b upwardly in direction BB to apply a closing force to the upper jaw 116a. The upper jaw 116a continues rotating further in direction CC toward a closed position. In FIG. 13, the I-beam member 216 is located past the ramp 204 and the upper jaw 116a is fully closed in response to the trigger plate 124 acting on the toggle clamp 145, which acts on the yoke 132, and advances the closure actuator 129 and the closure bar 142 to push on the pivoting link 178a. The I-beam member 216 pins 144a, 144b are now located past the ramp 204 and are located in the tracks 210a, 210b formed in the respective upper and lower jaws 116a, 116b. The I-beam member 216 is now prepared to slide distally in direction AA. In response to the trigger 109 being squeezed, the firing plate 128 rotates to advance the rack 136 distally, which acts on the firing bar 117 and pushes the I-beam member 216 and the cutting element 174 distally in direction AA. This action forces the jaws 116a, 116b fully shut to compress the tissue located therebetween.
With reference now to FIGS. 1-13, the disclosure now turns to a description of the electrosurgical instrument 102 having a separate spring driven cam closure mechanism for closing the jaws 110 that is independent of the I-beam 216 closure mechanism. In various embodiments, the present disclosure provides an electrosurgical radio frequency (RF) bipolar sealing device comprising a separate spring driven cam closure mechanism that is independent of the I-beam member 216 closure mechanism to simultaneously close a set of opposing jaws 116a, 116b. The spring driven cam closure system can close the jaws 116a, 116b first unless the force to close the jaws 116a, 116b overcomes a spring force. At this point, the I-beam member 216 closure system will close the jaws 116a, 116b. The spring driven cam closure mechanism comprises a spring 114 connected to a bar 142, which is in turn connected to a pivoting link 178a, which is then connected to a jaw 116a. Pushing on the spring 114 pushes on the bar 142, which pushes on the pivoting link 178a which closes the jaw 116a. The spring 114 of the cam closure system can be pre-compressed to raise its starting load.
The closure system of the electrosurgical instrument 102 comprises a first closure system comprising a spring driven cam closure mechanism and a second closure system comprising an I-beam closure mechanism. Both the first and second closure mechanisms are operated by the single trigger 109. The first closure system, otherwise referred to herein as a cam closure system, is driven by the closure of the trigger 109 in the first  ̃13 degrees of stroke. During the first stroke of the trigger 109, the trigger plate 124 drives the toggle clamp 145 and yoke 132 to advance the closure actuator 129 distally to compress the closure spring 114. The closure spring 114 drives the closure bar 142 which drives the pin 180a and the pivoting link 178a distally to close the upper jaw 116a independently of the I-beam closure mechanism. It should be noted that during the first stroke of the trigger 109, the rack 132 moves slightly distally to allow the driving bar 117 to push the I-beam member 216 from the base of the ramp 2014 to the top of the ramp 204. The second closure system is driven by the closure of the trigger in the last  ̃29 degrees of stroke. During the second stroke of the trigger 109, when the knife lockout mechanism is either unlocked or disabled, the firing plate 128 drives the first and second pinions 133, 134, which drives the rack 136 distally. The rack 136 is fixedly coupled to the firing bar 117, which drives the I-beam member 216 comprising the flexible cutting element 174.
The first closure system is configured to close the set of opposing jaws 116a, 116b in the end effector 110 using the closure spring 114 to drive the closure bar 142 to drive the pin 180a and the pivoting link 178a distally and close the upper jaw 116a onto the lower jaw 116b. The first closure system can apply more clamping force to the jaws 116a, 116b independently of the second closure system that employs the I-beam member 216 to close the jaws 116a, 116b. The additional closing force that is applied by the first closure system provides better grasping force between the jaws 116a, 116b than simply relying on the I-beam member 216 providing the initial closure force to the jaws 116a, 116b by moving the I-beam member 216 up to the top of the ramp 204.
To ensure that the I-beam member 206 will also be able to close the jaws 116a, 116b, the first and second closure systems operate in tandem. Thus, the cam closure drive system comprising the closure bar 142 and pivoting link 178a and I-beam drive system comprising the I-beam member 216 and firing bar 117 operate in tandem. In one embodiment, the cam closure system closes the jaws 116a, 116b and moves along with the I-beam member 216. Some conventional electrosurgical devices employ the toggle clamp 145 to move the I-beam member 216 to close the jaws 116a, 116b. In the present embodiment, however, the first closure system is operably coupled to the toggle clamp 145 in conjunction with the second closure system such that both closure systems advance distally at the same time. The cam closure system can be timed to close the jaws 116a, 116b before the I-beam member 216. The cam closure system also can incorporate an inline closure spring 114. The inline closure spring 114 can compress at the end of the closure stroke (after the first  ̃13 degrees of stroke of the trigger 109) to keep the jaws 116a, 116b shut with a set spring force.
When material is located between the jaws 116a, 116b, the closure spring 114 will be compressed over a predetermined limit during the first stroke closure phase of the cam closure system. After the predetermined limit, the I-beam member 216 closure system takes over the function of closing the jaws 116a, 116b. Accordingly, in the illustrated system the I-beam member 216 will ensure that the jaws 116a, 116b always fully close using jus the toggle clamp 145. The I-beam member 216 is configured to only close the jaws 116a, 116b when the material located between the jaws 116a, 116b takes more force to close than the cam closure spring 114 can provide. The cam system also provides a rising mechanical advantage as the upper jaw 116a is closed such that the more compression force is applied to the closure spring 114 the less force is exerted on the jaws 116a, 116b to prevent damaging tissue from too much spring force.
In one embodiment, the closure system comprising a first closure system (spring cam closure system) and a second an I-beam and spring driven cam system to simultaneously close a set of opposing jaws can be configured to operate in the following manner: (1) place tissue in the jaws and pull the trigger; (2) the toggle clamp pushes on the I-beam and the cam closure; (3) the cam immediately pushes on the jaw through a spring to close it, the I-beam trails a closure ramp on the upper jaw; (4) the cam fully closes the jaws before the toggle stops moving; (5) the toggle clamp continues to move (e.g., another 0.05 inches) to compress the closure spring to ensure the jaws are sprung closed, the I-beam moves over the top of the ramp; and (6) thick tissue in the jaws may compress the spring on the cam closure before the end of the toggle stroke, the I-beam will hit the closure ramp and force the jaws closed to ensure that the I-beam will repeatedly be located over the ramp with the jaws closed before the toggle stops moving.
The disclosed closure system comprising a first spring driven cam closure system and a second I-beam driven closure system is configured to simultaneously close a set of opposing jaws 116a, 116b and provides several advantages over conventional devices. The disclosed device is capable of sealing tissue without necessarily cutting the tissue, provides improved tissue grasping without actuating the cutting element 174, locates the I-beam member 216 over the ramp 204 before the I-beam 216 gear train takes over to provide lower force to fire the cutting element 174. The disclosed closure system also provides improved jaw 116a opening and tissue dissection over conventional devices. The disclosed closure system also provides lower force to fire from preload on tissue. The gears coupled to the firing plate 128 fire the I-beam member 216 distally and can be configured to operate with conventional electrosurgical jaw designs. Additional advantages, not necessarily described herein, are also provided.
FIGS. 14-23 provide a general description of the surgical instrument 102 shown in FIGS. 1 and 2 comprising a first spring driven cam closure system that operates independently of a second I-beam driven closure system. FIGS. 14-23 illustrate the surgical instrument 102 shown in FIGS. 1 and 2 with the jaw 110 fully open and the lockout defeat mechanism 108 enabled, e.g., in the “ON” position. FIG. 14 is a side elevational view of the surgical instrument 102 shown in FIGS. 1 and 2 with the left housing 106a shroud removed, shaft assembly 112 sheaths removed, the jaw 110 fully open and the lockout defeat mechanism 108 enabled, e.g., in the “ON” position, according to one embodiment. Thus, the button 139 portion of the slider 113 is slidably moved proximally to locate it in the B position.
FIG. 15 is a perspective view of the surgical instrument 102 shown in FIG. 14 with the right housing shroud 106b removed, according to one embodiment. FIG. 16 is a perspective view of the surgical instrument 102 shown in FIG. 15, according to one embodiment.
FIG. 17 is a side elevational view of the surgical instrument 102 shown in FIG. 14 with the right housing shroud 106b removed, according to one embodiment. The trigger 109 is located in the maximum distal position and the trigger plate 124 is engaged with the toggle clamp 145 and yoke 132, which are located in the maximum proximal position to set the jaws 110 in the fully open position. The slider 113 is set to the maximum proximal “B” position where the angled wall (ramp) 149 has rotated the lever arm 115. The lever arm 115 rotates the unlock arm 119 clockwise and the lockout element 165 counterclockwise to enable the lockout defeat mechanism 108. The lockout element 165 also depresses the energy button 122 to indicate that the lockout defeat mechanism 108 enabled in the “ON” position. This view also shows the position of the firing plate 128 sector gear meshed with the first pinion 133 prior to firing the cutting element. In this configuration the jaws 116a, 116b can be fully closed independently of the firing bar 117 driving the I-beam member 216 by squeezing the trigger 109 to drive the toggle clamp 145 and the closure spring 114.
FIG. 18 is a side elevational view of the surgical instrument shown in FIG. 17 with the firing plate 128 removed, according to one embodiment. This view illustrates the position of the trigger 109 relative to the trigger plate 124, the toggle clamp 145, and the yoke 132. This view also shows the first pinion 133 meshed with the second pinion 134 which located behind the firing plate 128.
FIG. 19 is a side elevational view of the surgical instrument 102 shown in FIG. 18 with the lockout defeat mechanism slider 113 removed, according to one embodiment, to better illustrate the position of the toggle clamp 145 when the jaws 110 are fully open.
FIG. 20 is a side elevational view of the surgical instrument 102 shown in FIG. 19 with the toggle clamp 145 and the yoke 132 removed, according to one embodiment. This view shows the position of the rack 136 and the lock arm 157 relative to the position of the slider 113. In addition, this view shows the second pinion 134 meshed with the rack 136 when the cutting element has not yet been fired.
FIG. 21 is a partial perspective view of the surgical instrument 102 shown in FIG. 20, according to one embodiment, which more clearly shows the lock arm 157 located in the notch 158 formed on top of the rack 136. When the unlock arm 119 is in the indicated position, as the toggle clamp 145 and yoke move in the distal direction, the unlock arm 119 acts on the lock arm 157 to disengage the lock arm 157 from the notch 158 in the rack 136 to defeat the lockout mechanism. Therefore, the rack 136 is able to advance distally when the firing plate 128 is rotated by the trigger 109.
FIG. 22 is a partial perspective view of the surgical instrument shown in FIG. 21 with the firing plate 128 replaced, according to one embodiment, to show the relative position of the firing plate 128, the first and second pinions 133, 134 and the rack 136 prior to firing the cutting element.
FIG. 23 is a partial perspective view of the surgical instrument 102 shown in FIG. 22 with the lockout defeat mechanism slider 113, lever arm 115, and lock arm 157 removed, according to one embodiment, to show the notch 158 or slot formed on top of the rack 136. As previously discussed, the lock arm 157 engages the notch 158 to prevent the rack 136 from advancing distally to fire the cutting element in response to the squeezing the trigger 109.
FIG. 24 is a side elevational view of the surgical instrument 102 shown in FIGS. 1 and 2 with the left and right housing shrouds 106a, 106b removed, shaft assembly 112 sheaths removed, the jaws 116a, 116b clamped and the lockout defeat mechanism 108 enabled, e.g., in the “ON” position, according to one embodiment. The trigger plate 124 is fully rotated counterclockwise to straighten the toggle clamp 145 and drive the yoke 132 distally in direction H. To fully close the jaw 110, the trigger 109 is squeezed in direction C to rotate the trigger plate 124 fully counterclockwise to straighten the toggle clamp 145 and advanced the yoke 132. Since the knife 174 has not been fired, the trigger 109 has not been fully squeezed and the firing plate 128 has not been rotated to actuate the rack 136. The yoke 132 is coupled to the closure actuator 129 which compresses the closure spring 114 and drives the closure bar 142. The closure bar 142 is coupled to the pivoting link 178a which closes the upper jaw 116a. 
FIG. 25 is a side elevational view of the surgical instrument 102 shown in FIGS. 1 and 2 with the left and right housing shrouds 106a, 106b removed, shaft assembly 112 sheaths removed, jaws 116a, 116b fully closed, knife 174 fully fired, and the lockout defeat mechanism 108 disabled, e.g., in the “OFF” position, according to one embodiment. The button 139 portion of the slider 113 is slidably moved distally to locate it in the A position. To fully close the jaw 110, the trigger 109 is squeezed in direction C to rotate the trigger plate 124 fully counterclockwise to straighten the toggle clamp 145 and advanced the yoke 132. As indicated by the position of the trigger 109 and the firing plate 128, the knife 174 is fully fired.
FIG. 26 is a side elevational view of the surgical instrument 102 shown in FIGS. 1 and 2 with the left and right housing shrouds 106a, 106b removed, shaft assembly 112 sheaths removed, jaws 116a,116b fully open, knife 174 not fired, and the lockout defeat mechanism disabled 108, e.g., in the “OFF” position, according to one embodiment. To fully fire the knife while the lockout defeat mechanism 108 disabled, e.g., in the “OFF” position (in other words, the lockout mechanism is enabled) the energy button 122 must be depressed to rotate the lockout element 165 counterclockwise and rotate the unlock arm 119 clockwise to kick the lock arm 157 out of the notch 158 in the rack 136 and unlock the lockout mechanism. Once the lockout mechanism in unlocked, the trigger 109 can be fully squeezed in direction C to rotate the firing plate 128 counterclockwise. This rotates the first pinion 133 clockwise, the second pinion 134 counterclockwise, and the rack 136 is driven distally to fire the firing bar 117 distally in direction H to fire the knife 174 and the I-beam member 216.
It is worthy to note that any reference to “one aspect,” “an aspect,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases “in one aspect,” “in an aspect,” “in one embodiment,” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects.
Although various embodiments have been described herein, many modifications, variations, substitutions, changes, and equivalents to those embodiments may be implemented and will occur to those skilled in the art. Also, where materials are disclosed for certain components, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations as falling within the scope of the disclosed embodiments. The following claims are intended to cover all such modification and variations.
Although various embodiments have been described herein, many modifications, variations, substitutions, changes, and equivalents to those embodiments may be implemented and will occur to those skilled in the art. Also, where materials are disclosed for certain components, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations as falling within the scope of the disclosed embodiments. The following claims are intended to cover all such modification and variations.

## Claims

1. A surgical instrument, comprising:
an end effector comprising:
a movable jaw comprising a first jaw member and a second jaw member, the first jaw member comprising a first track configured to slidably receive a first pin, the first jaw member comprising a ramp at a proximal end of the first track, the second jaw member comprising a second track configured to slidably receive a second pin; and
a cutting element slidably movable within the end effector, wherein the first and second pins are fixed to the cutting element, wherein the cutting element and the first and second pins define an I-beam member; and

a handle assembly comprising:
an energy button configured to deliver energy to at least one electrode located in the end effector;
a trigger plate operably coupled to a spring, the spring configured to move the first jaw member a first predetermined distance relative to the second jaw member independently of the I-beam member based on the spring generating a predetermined force;
a firing plate operably coupled to the I-beam member, the firing plate configured to drive the I-beam member based on a firing bar independently of the spring, wherein the I-beam member is configured to move the first jaw member relative to the second jaw member a second predetermined distance based on moving the I-beam member along the ramp and the first and second tracks from an initial position at a base of the ramp; and
a trigger operatively coupled to the trigger plate and the firing plate; and

wherein:
the spring and the I-beam member are configured to simultaneously move the first jaw member relative to the second jaw member, and
the predetermined force is less than a predetermined threshold.

2. The surgical instrument of claim 1, wherein the spring is further configured to provide a rising mechanical advantage.

3. The surgical instrument of claim 2, wherein the spring is pre-compressed to increase a starting load.

4. The surgical instrument of claim 2, further comprising:
a motion bar coupled to the spring; and
a pivoting link having a proximal end and a distal end, the proximal end coupled to the motion bar and the distal end coupled to the movable jaw.

5. The surgical instrument of claim 4, further comprising a closure actuator coupled to the spring and coupled to the trigger plate via a toggle clamp, wherein the closure actuator is configured to compress the spring.

6. The surgical instrument of claim 1, further comprising:
the firing bar having a proximal end and a distal end, wherein the cutting element is coupled to the distal end of the firing bar; and
a rack coupled to the proximal end of the firing bar, wherein the rack is operatively coupled to the firing plate.

7. The surgical instrument of claim 1, further comprising a lockout disabling mechanism comprising a lock arm operatively coupled to a lever arm and a lockout element, wherein the lockout element is configured to prevent driving the cutting element.

8. A surgical instrument, comprising:
an end effector comprising:
a movable jaw comprising a first jaw member and a second jaw member, the first jaw member comprising a first track configured to slidably receive a first pin, the first jaw member comprising a ramp at a proximal end of the first track, the second jaw member comprising a second track configured to slidably receive a second pin; and
a cutting element slidably movable within the end effector, wherein the first and second pins are fixed to the cutting element, wherein the cutting element and the first and second pins define an I-beam member; and

a spring configured to move the first jaw member a first predetermined distance relative to the second jaw member independently of the I-beam member; and
wherein:
the I-beam member is configured to independently move the first jaw member a second predetermined distance relative to the second jaw member based on moving the I-beam member along the ramp and the first and second tracks from an initial position at a base of the ramp,
the spring and the I-beam member are configured to simultaneously move the first jaw member relative to the second jaw member,
the first predetermined distance is less than a predetermined threshold distance.

9. The surgical instrument of claim 8, wherein the spring is pre-compressed to increase a starting load.

10. The surgical instrument of claim 8, further comprising:
a motion bar coupled to the spring; and
a pivoting link having a proximal end and a distal end, the proximal end coupled to the motion bar and the distal end coupled to the movable jaw.

11. The surgical instrument of claim 8, further comprising a closure actuator having a proximal end and a distal end, the distal end coupled to the spring and the proximal end coupled to a toggle clamp configured to drive the closure actuator, wherein the closure actuator is configured to compress the spring when the closure actuator moves in a distal direction.

12. The surgical instrument of claim 8, further comprising:
a firing bar having a proximal end and a distal end, wherein the cutting element is coupled to the distal end of the firing bar; and
a rack coupled to the proximal end of the firing bar, wherein the rack is operatively coupled to a firing plate.

13. The surgical instrument of claim 8, further comprising a lockout disabling mechanism comprising a lock arm operatively coupled to a lever arm and a lockout element, wherein the lockout element is configured to prevent driving the cutting element.

14. A surgical instrument, comprising:
a handle assembly comprising:
a trigger operatively coupled to a trigger plate and a firing plate;
an energy button configured to deliver energy to at least one electrode;
a lockout element operatively coupled to the energy button, the lockout element configured to prevent operation of the firing plate; and
a lockout disabling mechanism configured to disable the lockout element, the lockout disabling mechanism operable between a first position and a second position, wherein when the lockout disabling mechanism is located in the first position, the lockout element is enabled and can be unlocked by the energy button, and wherein when the lockout disabling mechanism is in the second position, the lockout element is disabled;

a shaft assembly comprising a proximal end and a distal end, wherein the shaft assembly is coupled to the handle assembly at the proximal end; and
an end effector coupled to the distal end of the shaft assembly, the end effector comprising:
a jaw assembly, comprising:
a first jaw member, the first jaw member comprising a first track configured to slidably receive a first pin, the first jaw member comprising a ramp at a proximal end of the first track; and
a second jaw member, the second jaw member comprising a second track configured to slidably receive a second pin, wherein rotation of the trigger plate transitions the jaw assembly between an open configuration and an approximated configuration by moving at least one of the first jaw member and the second jaw member relative to the other one of the first jaw member and the second jaw member;

a cutting element deployable in response to rotation of the firing plate wherein the first and second pins are fixed to the cutting element, wherein the cutting element and the first and second pins define an I-beam member;
a spring configured to move the first jaw member a first predetermined distance relative to the second jaw member independently of the I-beam member; and

wherein:
the I-beam member is configured to independently move the first jaw member a second predetermined distance relative to the second jaw member based on moving the I-beam member along the ramp and the first and second tracks from an initial position at a base of the ramp,
the spring and the I-beam member are configured to simultaneously move the first jaw member relative to the second jaw member; and
the first predetermined distance is less than a predetermined threshold distance.

15. The surgical instrument of claim 14, wherein the spring is pre-compressed to increase a starting load.

16. The surgical instrument of claim 14, further comprising:
a motion bar coupled to the spring; and
a pivoting link having a proximal end and a distal end, the proximal end coupled to the motion bar and the distal end coupled to the at least one of the first jaw member and the second jaw member.

17. The surgical instrument of claim 14, further comprising a closure actuator having a proximal end and a distal end, the distal end coupled to the spring and the proximal end coupled to a toggle clamp configured to drive the closure actuator, wherein the closure actuator is configured to compress the spring when the closure actuator moves in a distal direction.

18. The surgical instrument of claim 14, further comprising:
a firing bar having a proximal end and a distal end, wherein the cutting element is coupled to the distal end of the firing bar; and
a rack coupled to the proximal end of the firing bar, wherein the rack is operatively coupled to the firing plate.

19. The surgical instrument of claim 1, wherein the trigger is configured to actuate for a first stroke and for a second stroke, wherein the first stroke defines a rotation of the trigger from a first position to a second position, wherein the second stroke defines a rotation of the trigger from a third position to a fourth position.

20. The surgical instrument of claim 19, wherein the first stroke causes the spring to apply a first clamping force, wherein the second stroke causes the I-beam member to apply a second clamping force to move the first jaw member relative to the second jaw member.