Patent Publication Number: US-9421062-B2

Title: Surgical instrument shaft with resiliently biased coupling to handpiece

Description:
PRIORITY 
     This application claims priority to U.S. Provisional Application Ser. No. 61/410,603, filed Nov. 5, 2010, entitled “Energy-Based Surgical Instruments,” the disclosure of which is incorporated by reference herein. 
     This application also claims priority to U.S. Provisional Application Ser. No. 61/487,846, filed May 19, 2011, entitled “Energy-Based Surgical Instruments,” the disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND 
     In some settings, endoscopic surgical instruments may be preferred over traditional open surgical devices since a smaller incision may reduce the post-operative recovery time and complications. Consequently, some endoscopic surgical instruments may be suitable for placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors may engage tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, stapler, clip applier, access device, drug/gene therapy delivery device, and energy delivery device using ultrasound, RF, laser, etc.). Endoscopic surgical instruments may include a shaft between the end effector and a handle portion, which is manipulated by the clinician. Such a shaft may enable insertion to a desired depth and rotation about the longitudinal axis of the shaft, thereby facilitating positioning of the end effector within the patient. 
     Examples of endoscopic surgical instruments include those disclosed in U.S. Pat. Pub. No. 2006/0079874, entitled “Tissue Pad Use with an Ultrasonic Surgical Instrument,” published Apr. 13, 2006, the disclosure of which is incorporated by reference herein; U.S. Pat. Pub. No. 2007/0191713, entitled “Ultrasonic Device for Cutting and Coagulating,” published Aug. 16, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. Pub. No. 2007/0282333, entitled “Ultrasonic Waveguide and Blade,” published Dec. 6, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. Pub. No. 2008/0200940, entitled “Ultrasonic Device for Cutting and Coagulating,” published Aug. 21, 2008, the disclosure of which is incorporated by reference herein; U.S. Pat. Pub. No. 2011/0015660, entitled “Rotating Transducer Mount for Ultrasonic Surgical Instruments,” published Jan. 20, 2011, now U.S. Pat. No. 8,461,744, issued Jun. 11, 2013, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,500,176, entitled “Electrosurgical Systems and Techniques for Sealing Tissue,” issued Dec. 31, 2002, the disclosure of which is incorporated by reference herein; and U.S. Pat. Pub. No. 2011/0087218, entitled “Surgical Instrument Comprising First and Second Drive Systems Actuatable by a Common Trigger Mechanism,” published Apr. 14, 2011, now U.S. Pat. No. 8,939,974, issued Jan. 27, 2015, the disclosure of which is incorporated by reference herein. Additionally, such surgical tools may include a cordless transducer such as that disclosed in U.S. Pat. Pub. No. 2009/0143797, entitled “Cordless Hand-held Ultrasonic Cautery Cutting Device,” published Jun. 4, 2009, now U.S. Pat. No. 8,419,757, issued Apr. 16, 2013, the disclosure of which is incorporated by reference herein. In addition, the surgical instruments may be used, or adapted for use, in robotic-assisted surgery settings such as that disclosed in U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with Ultrasound Cauterizing and Cutting Instrument,” issued Aug. 31, 2004. 
     While several systems and methods have been made and used for surgical instruments, it is believed that no one prior to the inventors has made or used the invention described in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the specification concludes with claims which particularly point out and distinctly claim this technology, it is believed this technology will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which: 
         FIG. 1  depicts a perspective view of an exemplary surgical system comprising a surgical instrument and a generator; 
         FIG. 2  depicts a partial side elevation view of an exemplary surgical instrument with a portion of a cover removed to show the interior of a mating housing portion of an exemplary multi-piece handle assembly; 
         FIG. 3  depicts a partial perspective view of a distal end of an exemplary transducer; 
         FIG. 4  depicts a perspective view of an exemplary transmission assembly; 
         FIG. 5  depicts a partial view of the proximal end of an exemplary transmission assembly coupled to the distal end of an exemplary handle assembly; 
         FIG. 6  depicts a partial view of the proximal end of another exemplary transmission assembly coupled to the distal end of another exemplary handle assembly; 
         FIG. 7  depicts an elevation view of an exemplary rotator including tabs; 
         FIG. 8  depicts a fragmentary, perspective view of the exemplary rotator of  FIG. 7 ; 
         FIG. 9  depicts a cross-sectional view of the exemplary rotator of  FIG. 7  coupled with an exemplary multi-piece handle assembly and a shaft; 
         FIG. 10  depicts a perspective view of an alternative version of a connection of an exemplary shaft to a drive member; 
         FIG. 11  depicts a cross-sectional view of an alternative version of a connection of an exemplary shaft to a drive member in an unlocked position; 
         FIG. 12  depicts the exemplary shaft and drive member of  FIG. 11  in a locked position; 
         FIG. 13  depicts a partial view of the proximal end of a transmission assembly coupled with the distal end of a handle assembly; 
         FIG. 14  depicts a partial view of the transmission assembly of  FIG. 13  decoupling from the handle assembly of  FIG. 13 ; and 
         FIG. 15  depicts an elevation view of an exemplary surgical instrument having a tapered male waveguide end configured to non-threadably attach to a corresponding tapered female transducer end. 
     
    
    
     The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the technology may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present technology, and together with the description serve to explain the principles of the technology; it being understood, however, that this technology is not limited to the precise arrangements shown. 
     DETAILED DESCRIPTION 
     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. 
     I. Overview of Exemplary Ultrasonic Surgical System 
       FIG. 1  shows an exemplary ultrasonic surgical system ( 10 ) comprising an ultrasonic surgical instrument ( 50 ), a generator ( 20 ), and a cable ( 30 ) coupling generator ( 20 ) to surgical instrument ( 50 ). In some versions, generator ( 20 ) comprises a GEN 300 sold by Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. By way of example only, generator ( 20 ) may be constructed in accordance with the teachings of U.S. Pub. No. 2011/0087212, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, now U.S. Pat. No. 8,986,302, issued Mar. 24, 2015, the disclosure of which is incorporated by reference herein. While surgical instrument ( 50 ) is described herein as an ultrasonic surgical instrument, it should be understood that the teachings herein may be readily applied to a variety of surgical instruments, including but not limited to endocutters, graspers, cutters, staplers, clip appliers, access devices, drug/gene therapy delivery devices, and energy delivery devices using ultrasound, RF, laser, etc., and/or any combination thereof as will be apparent to one of ordinary skill in the art in view of the teachings herein. Moreover, while the present example will be described in reference to a cable-connected surgical instrument ( 50 ), it should be understood that surgical instrument ( 50 ) may be adapted for cordless operation, such as that disclosed in U.S. Pat. Pub. No. 2009/0143797, entitled “Cordless Hand-held Ultrasonic Cautery Cutting Device,” published Jun. 4, 2009, now U.S. Pat. No. 8,419,757, the disclosure of which is incorporated by reference herein. For instance, surgical device ( 50 ) may include an integral and portable power source such as a battery, etc. Furthermore, surgical device ( 50 ) may also be used, or adapted for use, in robotic-assisted surgery settings such as that disclosed in U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with Ultrasound Cauterizing and Cutting Instrument,” issued Aug. 31, 2004. 
     Surgical instrument ( 50 ) of the present example includes a multi-piece handle assembly ( 60 ), an elongated transmission assembly ( 70 ), and a transducer ( 100 ). Transmission assembly ( 70 ) is coupled to multi-piece handle assembly ( 60 ) at a proximal end of transmission assembly ( 70 ) and extends distally from multi-piece handle assembly ( 60 ). In the present example, transmission assembly ( 70 ) is configured as an elongated, thin tubular assembly for endoscopic use, but it should be understood that transmission assembly ( 70 ) may alternatively be a short assembly, such as those disclosed in U.S. Pat. Pub. No. 2007/0282333, entitled “Ultrasonic Waveguide and Blade,” published Dec. 6, 2007, and U.S. Pat. Pub. No. 2008/0200940, entitled “Ultrasonic Device for Cutting and Coagulating,” published Aug. 21, 2008, the disclosures of which are incorporated by reference herein. Transmission assembly ( 70 ) of the present example comprises an outer sheath ( 72 ), an inner tubular actuating member (not shown), a waveguide (not shown), and an end effector ( 80 ) located on the distal end of transmission assembly ( 70 ). In the present example, end effector ( 80 ) comprises a blade ( 82 ) that is mechanically and acoustically coupled to the waveguide, a clamp arm ( 84 ) operable to pivot at the proximal end of transmission assembly ( 70 ), and a clamp pad ( 86 ) coupled to clamp arm ( 84 ). It should also be understood that clamp arm ( 84 ) and associated features may be constructed and operable in accordance with at least some of the teachings of U.S. Pat. No. 5,980,510, entitled “Ultrasonic Clamp Coagulator Apparatus Having Improved Clamp Arm Pivot Mount,” issued Nov. 9, 1999, the disclosure of which is incorporated by reference herein. Exemplary versions of end effector ( 80 ) and transmission assembly ( 70 ) will be discussed in greater detail below in reference to the example shown in  FIG. 4 . 
     In some versions, transducer ( 100 ) comprises a plurality of piezoelectric elements (not shown) that are compressed between first resonator (not shown) and second resonator (not shown) to form a stack of piezoelectric elements. The piezoelectric elements may be fabricated from any suitable material, for example, lead zirconate-titanate, lead meta-niobate, lead titanate, and/or any suitable piezoelectric crystal material, for example. Transducer ( 100 ) further comprises electrodes, including at least one positive electrode and at least one negative electrode that are configured to create a voltage potential across the one or more piezoelectric elements, such that the piezoelectric elements convert the electrical power into ultrasonic vibrations. The ultrasonic vibrations are transmitted to blade ( 82 ) via the waveguide in transmission assembly ( 70 ). 
     Multi-piece handle assembly ( 60 ) of the present example comprises a mating housing portion ( 62 ) and a lower portion ( 64 ). Mating housing portion ( 62 ) is configured to receive transducer ( 100 ) at a proximal end of mating housing portion ( 62 ) and to receive the proximal end of transmission assembly ( 70 ) at a distal end of mating housing portion ( 62 ). A rotation knob ( 66 ) is shown in the present example to rotate transmission assembly ( 70 ) and transducer ( 100 ), but it should be understood that rotation knob ( 66 ) is merely optional. Mating housing portion ( 62 ) will be discussed in greater detail below in reference to  FIG. 2 . Lower portion ( 64 ) of multi-piece handle assembly ( 60 ) shown in  FIG. 1  includes a trigger ( 68 ) and is configured to be grasped by a user using a single hand. One merely exemplary alternative version for lower portion ( 64 ) is depicted in FIG. 1 of U.S. Pat. Pub. No. 2011/0015660, entitled “Rotating Transducer Mount for Ultrasonic Surgical Instruments,” published Jan. 20, 2011, now U.S. Pat. No. 8,461,744, the disclosure of which is incorporated by reference herein. Toggle buttons ( 69 ), shown in  FIG. 2  of the present disclosure, are located on a distal surface of lower portion ( 64 ) and are operable to selectively activate transducer ( 100 ) at different operational levels using generator ( 20 ). For instance, a first toggle button ( 69 ) may activate transducer ( 100 ) at a maximum energy level while a second toggle button ( 69 ) may activate transducer ( 100 ) at a minimum, non-zero energy level. Of course, toggle buttons ( 69 ) may be configured for energy levels other than a maximum and/or minimum energy level as will be apparent to one of ordinary skill in the art in view of the teachings herein. Moreover, the toggle buttons may be located anywhere else on multi-piece handle assembly ( 60 ), on transducer ( 100 ), and/or remote from surgical instrument ( 50 ), and any number of toggle buttons may be provided. While multi-piece handle assembly ( 60 ) has been described in reference to two distinct portions ( 62 ,  64 ), it should be understood that multi-piece handle assembly ( 60 ) may be a unitary assembly with both portions ( 62 ,  64 ) combined. Multi-piece handle assembly ( 60 ) may alternatively be divided into multiple discrete components, such as a separate trigger portion (operable either by a user&#39;s hand or foot) and a separate mating housing portion ( 62 ). Such a trigger portion may be operable to activate transducer ( 100 ) and may be remote from mating housing portion ( 62 ). Multi-piece handle assembly ( 60 ) may be constructed from a durable plastic (such as polycarbonate or a liquid crystal polymer), ceramics, metals, and/or any other suitable material as will be apparent to one of ordinary skill in the art in view of the teachings herein. Other configurations for multi-piece handle assembly ( 60 ) will also be apparent to those of ordinary skill in the art in view of the teachings herein. By way of example only, surgical instrument ( 50 ) may be constructed in accordance with at least some of the teachings of U.S. Pat. Pub. No. 2006/0079874; U.S. Pat. Pub. No. 2007/0191713; U.S. Pat. Pub. No. 2007/0282333; U.S. Pat. Pub. No. 2008/0200940; U.S. Pat. Pub. No. 2011/0015660, now U.S. Pat. No. 8,461,744; U.S. Pat. No. 6,500,176; U.S. Pat. Pub. No. 2011/0087218, now U.S. Pat. No. 8,939,974; and/or U.S. Pat. Pub. No. 2009/0143797, now U.S. Pat. No. 8,419,757. 
     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. 
     II. Exemplary Coupling Assemblies for Ultrasonic Surgical Instrument 
     In some instances it may be useful to detach transmission assembly ( 70 ) from multi-piece handle assembly ( 60 ) and transducer ( 100 ). For instance, a detachable transmission assembly ( 70 ) may permit the reuse of multi-piece handle assembly ( 60 ) with multiple transmission assemblies ( 70 ) having various end effectors ( 80 ). By way of example only, the various end effectors ( 80 ) may have different sized and/or shaped blades ( 82 ) or the various end effectors ( 80 ) may have entirely different functions, such as RF end effectors, stapling end effectors, cutting end effectors, etc. Furthermore, a single multi-piece handle assembly ( 60 ) may be reused for different operations by a user by removing a dirty transmission assembly ( 70 ), optionally cleaning multi-piece handle assembly ( 60 ), and coupling a new transmission assembly ( 70 ) to multi-piece handle assembly ( 60 ) for a new operation. Accordingly, configuring multi-piece handle assembly ( 60 ) to couple with a variety of transmission assemblies ( 70 ) may be preferable for some users of surgical instrument ( 50 ). 
     A. Exemplary Multi-Piece Handle Assembly 
       FIG. 2  shows a partial side view of multi-piece handle assembly ( 60 ) with a portion of a cover ( 61 ) removed to show the internal components contained within mating housing portion ( 62 ) and a section of lower portion ( 64 ). As described above, lower portion ( 64 ) includes a pivotable trigger ( 68 ) and a pair of toggle buttons ( 69 ). Trigger ( 68 ) of the present example is pivotable from a distal, open position to a proximal, closed position. A trigger assembly ( 150 ) is coupled to trigger ( 68 ) and is pivotally supported within multi-piece handle assembly ( 60 ). Trigger assembly ( 150 ) of the present example comprises a pivotable attachment arm ( 152 ) that may be pivoted about a pin (not shown), a trigger arm ( 154 ), an intermediate link ( 156 ), and an actuation arm ( 158 ). Actuation arm ( 158 ) is coupled to a trigger yoke ( 170 ) at the distal end of actuation arm ( 158 ). Actuation arm ( 158 ) comprises one or more mounting pins ( 160 ) extending outwardly from actuation arm ( 158 ) and pins ( 160 ) are sized to be slidably received in corresponding elongated channel ( 162 ) formed in cover ( 61 ). Accordingly, when trigger ( 68 ) is pivoted proximally from the open position to the closed position attachment arm ( 152 ) and trigger arm ( 154 ) pivot within multi-piece handle assembly ( 60 ). Intermediate link ( 156 ) coupled to trigger arm ( 154 ) transfers this pivoting motion from trigger arm ( 154 ) to actuation arm ( 158 ) to slidably translate actuation arm ( 158 ) proximally via pins ( 160 ) within channel ( 162 ). Trigger yoke ( 170 ), which is coupled to actuation arm ( 158 ), is translated proximally as well. In the present example, trigger yoke ( 170 ) is coupled to a force-limiting mechanism ( 180 ), which is further coupled to transmission assembly ( 70 ) as will be described in more detail below, to operate inner tubular actuating member ( 74 ). A cavity ( 140 ), shown in  FIG. 2 , is configured to receive transducer ( 100 ) therein from a transducer aperture ( 142 ) formed in cover ( 61 ). Cavity ( 140 ) is configured to receive at least a portion of transducer ( 100 ) therein such that transducer ( 100 ) and transmission assembly ( 70 ) may be coupled together. Still other configurations for multi-piece handle assembly ( 60 ) will be apparent to one of ordinary skill in the art in view of the teachings herein. 
     B. Exemplary Transducer 
     As shown in  FIG. 3 , transducer ( 100 ) of the present example is a tubular component that is coupled to generator ( 20 ) via cable ( 30 ), though it should be understood that transducer ( 100 ) may instead be a cordless transducer. For instance, transducer ( 100 ) may instead receive power from a power source that is contained within handle assembly ( 60 ), in accordance with the teachings of various references cited herein or otherwise. In the present example, transducer ( 100 ) includes a first conductive ring ( 102 ) and a second conductive ring ( 104 ), which are disposed within a body ( 110 ) of transducer ( 100 ). In the present example, first conductive ring ( 102 ) comprises a ring member having one or more electrical contacts that are disposed on the ring member and that are configured to electrically couple first conductive ring ( 102 ) to a power source. First conductive ring ( 102 ) is disposed between body ( 110 ) and a horn ( 120 ) extending distally from body ( 110 ). Horn ( 120 ) comprises distal horn threads ( 122 ) such that horn ( 120 ) is coupleable to waveguide ( 210 ), as will be discussed below in reference to  FIG. 4 . First conductive ring ( 102 ) of the present example is coaxial with and adjacent to a flange ( 106 ). Flange ( 106 ) of the present example is configured to further mechanically couple transducer ( 100 ) within multi-piece handle assembly ( 60 ). A transducer cavity ( 108 ) is disposed between first conductive ring ( 102 ) and a second conductive ring ( 104 ) such that first conductive ring ( 102 ) is electrically isolated from second conductive ring ( 104 ) and/or other conductive components of transducer ( 100 ). First conductive ring ( 102 ) is located on a non-conductive platform extending distally from body ( 110 ). First conductive ring ( 102 ) is electrically coupled to cable ( 30 ), shown in  FIG. 1 , by one or more electrical wires or conductive etchings (not shown) within body ( 110 ). Such electrical coupling of first conductive ring ( 102 ) to cable ( 30 ) may include a slip ring to facilitate free rotation of transducer ( 100 ) relative to cable ( 30 ). 
     Second conductive ring ( 104 ) of transducer ( 100 ) similarly comprises a ring member that is disposed between body ( 110 ) and horn ( 120 ). Second conductive ring ( 104 ) is disposed between first conductive ring ( 102 ) and horn ( 120 ). As is shown in  FIG. 3 , first and second conductive rings ( 102 ,  104 ) are coaxial members. Second conductive ring ( 104 ) is likewise electrically isolated from first conductive ring ( 102 ) and other conductive components of transducer ( 100 ). Similar to first conductive ring ( 102 ), second conductive ring ( 104 ) extends from the non-conductive platform. One or more washer-shaped spacers ( 112 ) may be disposed between second conductive ring ( 104 ) and horn ( 120 ) to isolate the vibrations transmitted through horn ( 120 ) from the other components of transducer ( 100 ). Second conductive ring ( 104 ) is also electrically coupled to cable ( 30 ), shown in  FIG. 1 , by one or more electrical wires or conductive etchings (not shown) within body ( 110 ). Such electrical coupling of second conductive ring ( 104 ) to cable ( 30 ) may also include a slip ring to facilitate free rotation of transducer ( 100 ) relative to cable ( 30 ). One merely exemplary suitable ultrasonic transducer ( 100 ) is Model No. HP054, sold by Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio, though it should be understood that any other suitable transducer may be used. 
     As shown in the present example, the distal end of transducer ( 100 ) threadably couples to the proximal end of a transmission assembly via horn ( 120 ). The distal end of transducer ( 100 ) also interfaces with one or more electrical connections (not shown) via first and second conductive rings ( 102 ,  104 ) to electrically couple transducer ( 100 ) to toggle buttons ( 69 ) to provide a user with finger-activated controls for activating transducer ( 100 ) while using surgical instrument ( 50 ). The interface between the one or more electrical connections and the first and second conductive rings ( 102 ,  104 ) may include a slip ring connection to permit free rotation of transducer ( 100 ) relative to multi-piece handle assembly ( 60 ). Still other configurations for transducer ( 100 ) will be apparent to one of ordinary skill in the art in view of the teachings herein. For instance, first and second conductive rings ( 102 ,  104 ) may be omitted from the distal end of transducer ( 100 ) and the electrical coupling of transducer ( 100 ) to toggle buttons ( 69 ) may be accomplished by alternative structures, such as conductors at the proximal end of transducer ( 100 ), conductors located along the side of body ( 110 ) of transducer ( 100 ), directly from cable ( 30 ), and/or otherwise. When transducer ( 100 ) of the present example is activated via a toggle button ( 69 ), transducer ( 100 ) is operable to create mechanical energy in the form of linear oscillations or vibrations, at an ultrasonic frequency (such as 55.5 kHz). When transducer ( 100 ) is coupled to transmission assembly ( 70 ) via horn ( 120 ), these mechanical oscillations are transmitted through the internal waveguide of transmission assembly ( 70 ) to end effector ( 80 ). In the present example, with blade ( 82 ) being coupled to the waveguide, blade ( 82 ) thereby oscillates at the ultrasonic frequency. Thus, when tissue is secured between blade ( 82 ) and clamp arm ( 84 ), the ultrasonic oscillation of blade ( 82 ) may simultaneously sever the tissue and denature the proteins in adjacent tissue cells, thereby providing a coagulative effect with relatively little thermal spread. An electrical current may also be provided through blade ( 82 ) and clamp arm ( 84 ) to also cauterize the tissue. While some configurations for transmission assembly ( 70 ) and transducer ( 100 ) have been described, still other suitable configurations for transmission assembly ( 70 ) and transducer ( 100 ) will be apparent to one of ordinary skill in the art in view of the teachings herein. 
     C. Exemplary Transmission Assembly for Threaded Attachment 
     As noted previously, in some instances it may be useful to detach transmission assembly ( 70 ) from multi-piece handle assembly ( 60 ) and transducer ( 100 ). Merely exemplary instances include the use of multi-piece handle assembly ( 60 ) with multiple transmission assemblies ( 70 ) having different sized and/or shaped blades ( 82 ), use with various end effectors ( 80 ) with entirely different functions and/or modalities (e.g., RF end effectors, stapling end effectors, cutting end effectors, etc.), or for reuse of a single multi-piece handle assembly ( 60 ) for multiple operations by a user. Accordingly, a version permitting the user to swap transmission assemblies ( 70 ) with multi-piece handle assembly ( 60 ) may be useful. 
     One merely exemplary transmission assembly ( 200 ) is shown in  FIG. 4  having a proximal end ( 202 ), a distal end ( 204 ), a waveguide ( 210 ), an inner tubular actuating member ( 220 ), an outer sheath ( 230 ), and an end effector ( 240 ) at the distal end of transmission assembly ( 200 ). In the present example, waveguide ( 210 ), inner tubular actuating member ( 220 ), and outer sheath ( 230 ) are coaxial members with waveguide ( 230 ) in the center, inner actuating member ( 220 ) disposed about waveguide ( 210 ), and outer sheath ( 230 ) disposed about inner actuating member ( 220 ). 
     Referring to distal end ( 204 ) of transmission assembly ( 200 ) first, end effector ( 240 ) comprises a blade ( 242 ), a clamp arm ( 244 ), and one or more optional clamp pads ( 246 ). In the present example, blade ( 242 ) is coupled to waveguide ( 210 ) such that the mechanical vibrations transmitted to waveguide ( 210 ) from transducer ( 100 ) are also transmitted to blade ( 242 ). Merely exemplary couplings for blade ( 242 ) to waveguide ( 210 ) include welding blade ( 242 ) to waveguide ( 210 ), integrally forming blade ( 242 ) with waveguide ( 210 ), mechanically or chemically coupling blade ( 242 ) to waveguide ( 210 ), and/or any other suitable configuration as will be apparent to one of ordinary skill in the art in view of the teachings herein. In some versions, blade ( 242 ) is a curved blade, such as blade ( 242 ) shown in  FIG. 4 ; and in some versions blade ( 242 ) may be a straight blade. Furthermore, blade ( 242 ) may have a variety of shapes and sizes. In the present example, blade ( 242 ) is a tapered rectangular blade, though it should be understood that blade ( 242 ) may be cylindrical, triangular, hemi-cylindrical, square, hooked, and/or any other shape for blade ( 242 ). Furthermore, additional features may be added to blade ( 242 ), including spherical tips, hooked tips, square tips, serrated edging, and/or any other additional features. Still other configurations for blade ( 242 ) will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     Clamp arm ( 244 ) of the present example is a curved member that corresponds to the curvature of blade ( 242 ). Clamp arm ( 244 ) may optionally include clamp pads ( 246 ) to grip or secure tissue against blade ( 242 ). Such clamp pads may be configured in accordance with at least some of the teachings of U.S. Pat. Pub. No. 2006/0079874, entitled “Tissue Pad Use with an Ultrasonic Surgical Instrument,” published Apr. 13, 2006. Pivotal movement of clamp arm ( 244 ) with respect to blade ( 242 ) is accomplished by a first pair of pivot points ( 248 ) on clamp arm ( 244 ) that pivotally couple to outer sheath ( 230 ) and a second set of pivot points ( 249 ) on clamp arm ( 244 ) that pivotally couple to inner tubular actuating member ( 220 ). In the present example, outer sheath ( 230 ) is coupleable to multi-piece handle assembly ( 60 ) through a rotation knob ( 250 ), thereby grounding outer sheath ( 230 ). First set of pivot points ( 248 ) of clamp arm ( 244 ) are pivotally connected to outer sheath ( 230 ) via corresponding through holes ( 232 ) on outer sheath ( 230 ). In some versions, first set of pivot points ( 248 ) comprise through holes and a securing pin or rivet may be inserted through first set of pivot points ( 248 ) and through through holes ( 232 ) to secure clamp arm ( 244 ) to outer sheath ( 230 ). The pin in this version may be laser welded to clamp arm ( 244 ) or the pin may be laser welded to outer sheath ( 230 ). Of course through holes ( 232 ) may instead be outwardly extending pins and first set of pivot points ( 248 ) may be through holes. Still other configurations for first set of pivot points ( 248 ) and through holes ( 232 ) will be apparent to one of ordinary skill in the art in view of the teachings herein. 
     Second set of pivot points ( 249 ) of clamp arm ( 244 ) are pivotally connected to inner tubular actuating member ( 220 ) via corresponding through holes ( 222 ) on inner tubular actuating member ( 220 ). In some versions, second set of pivot points ( 249 ) comprise through holes and a securing pin or rivet may be inserted through second set of pivot points ( 249 ) and through through holes ( 222 ) to secure clamp arm ( 244 ) to inner tubular actuating member ( 220 ). The pin in this version may be laser welded to clamp arm ( 244 ) or the pin may be laser welded to inner tubular actuating member ( 220 ). Of course through holes ( 222 ) may instead be outwardly extending pins and second set of pivot points ( 249 ) may be through holes. Still other pivotable configurations for second set of pivot points ( 249 ) and through holes ( 222 ) will be apparent to one of ordinary skill in the art in view of the teachings herein. 
     With clamp arm ( 244 ) so secured to outer sheath ( 230 ) and inner tubular actuating member ( 220 ), clamp arm ( 244 ) is pivotable when inner tubular actuating member ( 220 ) translates longitudinally. In the present example, inner tubular actuating member ( 220 ) is translatable relative to the longitudinal axis of outer sheath ( 230 ) and is coupled to force-limiting mechanism ( 180 ) within multi-piece handle assembly ( 60 ). Thus, when force-limiting mechanism ( 180 ) translates via trigger ( 68 ) and trigger assembly ( 150 ), clamp arm ( 244 ) is pivotable from an open position to a closed position. It should be understood that, as with other components referred to herein, clamp arm ( 84 ,  244 ) is merely optional. Likewise, trigger ( 68 ) and trigger assembly ( 150 ) and the components described herein for pivoting clamp arm ( 84 ,  244 ) are also merely optional. Thus, some versions of end effector ( 80 ,  240 ) may simply consist of a blade ( 82 ,  842 ) and/or other features. 
     As shown in  FIG. 4 , a spacer ( 290 ) is insertable between clamp arm ( 244 ) and blade ( 242 ) to maintain clamp arm ( 244 ) in the open position. Spacer ( 290 ) has a flat bottom surface ( 292 ) and an angled top surface ( 294 ) in this example. Top surface ( 294 ) is set at an angle to maintain clamp arm ( 244 ) in the open position relative to blade ( 242 ) when bottom surface ( 292 ) abuts blade ( 242 ). In some versions, bottom surface ( 292 ) may be configured to snap or clip onto blade ( 242 ) to secure spacer ( 290 ) relative to blade ( 242 ). Alternatively, a recess may be provided in spacer ( 290 ) such that spacer ( 290 ) may be slid onto blade ( 242 ). Further still, an adhesive may be applied to bottom surface ( 292 ) and/or top surface ( 294 ) to also secure spacer ( 290 ). Thus, when spacer ( 290 ) is inserted between clamp arm ( 244 ) and blade ( 242 ), clamp arm ( 244 ) is prevented from pivoting to a closed position. This may permit a user to couple transmission assembly ( 200 ) to multi-piece handle assembly ( 60 ) while maintaining both clamp arm ( 244 ) and trigger ( 68 ) in their respective open positions. Alternatively, a user may couple transmission assembly ( 200 ) to multi-piece handle assembly ( 60 ) without the use of spacer ( 290 ). For example, the user may couple different components of transmission assembly ( 200 ) with different components of handle assembly ( 60 ) at different times, such as in the manner described below or otherwise. 
     Referring now to distal end ( 202 ) of transmission assembly ( 200 ), a rotation knob ( 250 ) couples outer sheath ( 230 ) to multi-piece handle assembly ( 60 ). In the present example, rotation knob ( 250 ) comprises an inner ring portion (not shown) having one or more connectors ( 252 ) extending proximally therefrom, an outer ring ( 254 ), and a pin (not shown) extending through outer ring ( 254 ), outer sheath ( 230 ), inner tubular actuating member ( 220 ), and waveguide ( 210 ). Accordingly, when outer ring ( 254 ) of rotation knob ( 250 ) is rotated, waveguide ( 210 ), inner tubular actuating member ( 220 ), and outer sheath ( 230 ) also rotate. Inner ring portion and outer ring ( 254 ) of the present example are complementary bearing components such that outer ring ( 254 ) is rotatable relative to inner ring portion. It should be understood that the pin does not extend though inner ring portion. As previously noted, inner ring portion includes connectors ( 252 ). In the present example connectors ( 252 ) are shown as snap-fit connectors, though other suitable connecting features, such as threading, adhesives, pins, clips, snaps, and/or other connectors may be used as will be apparent to one of ordinary skill in the art in view of the teachings herein. When transmission assembly ( 200 ) is assembled with multi-piece handle assembly ( 60 ) and transducer ( 100 ), as will be discussed below, connectors ( 252 ) of the present example insert into one or more recesses (not shown) and couple rotation knob ( 250 ) to cover ( 61 ) of multi-piece handle assembly ( 60 ). A release mechanism, such as a push button (not shown) on multi-piece handle assembly ( 60 ) or on rotation knob ( 250 ) may be provided to decouple connectors ( 252 ) from cover ( 61 ) when transmission assembly ( 200 ) is to be removed. Alternatively, connectors ( 252 ) may be designed to break-away when transmission assembly ( 200 ) is decoupled. Further still, if threading is used, inner portion of rotation knob ( 250 ) may be rotated to decouple from multi-piece handle assembly ( 60 ). Still other suitable configurations for rotation knob ( 250 ) will be apparent to one of ordinary skill in the art in view of the teachings herein. 
     Still referring to proximal end ( 202 ) of transmission assembly ( 200 ), external threads ( 228 ) are included at the proximal end of inner tubular actuating member ( 220 ) as shown in  FIG. 4 . External threads ( 228 ) screw into complementary threads (not shown) of force-limiting mechanism ( 180 ), which is in turn driven by trigger assembly ( 150 ). Additionally, a recess having internal threading ( 218 ) is included at the proximal end of waveguide ( 210 ) as shown in  FIG. 4 . Internal threading ( 218 ) screws onto horn threads ( 122 ) to mechanically and acoustically couple waveguide ( 210 ) to transducer ( 100 ). Of course other suitable configurations for transmission assembly ( 200 ) will be apparent to one or ordinary skill in the art in view of the teachings herein. Similarly, various other suitable ways in which transmission assembly ( 200 ) may be coupled with handle assembly ( 60 ) will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     III. Exemplary Removable Shaft Connections to Handle Portions 
     Versions described below discuss connections and uses of disposable transmission assemblies that are alternative versions of transmission assembly ( 70 ) described above. The alternative versions of transmission assembly ( 70 ) include components that permit the alternative transmission assemblies to be selectively coupleable and adjustable with transducer ( 100 ), for example, in respective reusable handle portions of ultrasonic surgical instruments. Additional exemplary modifications that may be provided for transmission assembly ( 70 ) selectively coupleable to multi-piece handle assembly ( 60 ) and transducer ( 100 ) of instrument ( 50 ) will be described in greater detail below. Various suitable ways in which the below teachings may be incorporated into instrument ( 50 ) will be apparent to those of ordinary skill in the art. Similarly, various suitable ways in which the below teachings may be combined with various teachings of the references cited herein will be apparent to those of ordinary skill in the art. It should also be understood that the below teachings are not limited to instrument ( 50 ) or devices taught in the references cited herein. The below teachings may be readily applied to various other kinds of instruments, including instruments that would not be classified as ultrasonic surgical instruments. Various other suitable devices and settings in which the below teachings may be applied will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     A. Exemplary Ball Detent Connection 
       FIG. 5  shows the connection of yoke ( 170 ) to force-limiting mechanism ( 180 ) of transmission assembly ( 70 ). Yoke ( 170 ) includes posts ( 300 ) which are captured within notches ( 302 ) in force-limiting mechanism ( 180 ). Posts ( 300 ) transmit force such as a high, distally oriented closure force to drive a clamping portion of the end effector for good vessel coaptation during cutting; and a smaller, proximally oriented opening force for dissection. 
       FIG. 6  shows an alternative version using spring loaded ball detents assembly ( 304 ) in yoke ( 306 ) rather than posts to latch into notches ( 308 ) defined within proximal end ( 310 ) of transmission assembly ( 312 ). Spring loaded ball detents assembly ( 304 ) includes ball bearings or detents ( 314 ) attached to ends of biasing members such as springs ( 316 ). Detents ( 314 ) assist to connect transmission assembly ( 312 ) to mating housing portion ( 62 A) of cover ( 61 A) of surgical instrument ( 50 A). Surgical instrument ( 50 A) is similar to surgical instrument ( 50 ) described above with the exception of the differences described below regarding the connection and release of the transmission assembly ( 312 ) respectively to and from surgical instrument ( 50 A). The same applies to other versions of surgical instruments described below and herein. Similarly, versions of transmission assemblies described below and herein each include a rotation knob, such as knob ( 66 A), and a shaft, such as outer sheath ( 317 ), which is similar to outer sheath ( 72 ) of transmission assembly ( 70 ) and outer sheath ( 230 ) of transmission assembly ( 200 ). Outer sheath ( 317 ) may rotate relative to the handpiece of instrument ( 50 A) but does not translate relative to the handpiece. 
     When connecting transmission assembly ( 312 ) to a reusable handle portion of surgical instrument ( 50 A), proximal end ( 310 ) of assembly ( 312 ) pushes detents ( 314 ) outwardly and away from assembly ( 312 ) until detents ( 314 ) are aligned with notches ( 308 ), at which point springs ( 316 ) apply a biasing force to mate detents ( 314 ) with notches ( 308 ). This force removably connects assembly ( 312 ) to yoke ( 306 ) of instrument ( 50 A). Yoke ( 306 ) is similar to yoke ( 170 ) of transmission assembly ( 70 ). Yoke ( 306 ) translates within the handpiece of instrument ( 50 A) based on pivotal movement of the trigger (not shown) relative to the handpiece, where the trigger is similar in structure and operation to trigger ( 68 ) of transmission assembly ( 70 ). Proximal end ( 310 ) of assembly ( 312 ) includes an inner tube portion similar to inner tubular actuating member ( 220 ) of transmission assembly ( 200 ). The inner tube portion of proximal end ( 310 ) translates within yoke ( 306 ) relative to the handpiece of instrument ( 50 A) and includes an internal tube extending through and translating within outer sheath ( 317 ). When the internal tube translates in a first direction (e.g., proximally), the internal tube pivots clamp arm ( 244 ) toward blade ( 242 ). When the internal tube translates in a second, opposite direction (e.g., distally), the internal tube pivots clamp arm ( 244 ) away from blade ( 242 ). 
     In some other versions, the internal tube may remain stationary while outer sheath ( 317 ) translates distally to close clamp arm ( 244 ) against blade ( 242 ). As another merely illustrative variation, the internal tube may engage pivots on clamp arm ( 244 ) and outer sheath ( 317 ) may engage fixed driver pins, thus allowing for a distal motion of internal tube to close clamp arm ( 244 ) against blade ( 242 ). Yet another merely illustrative version involves having both pivot pins and drive pins positioned on an upper side of clamp arm ( 244 ), with the drive pins disposed slightly higher than the pivot pins, such that distal translation of the internal tube would close clamp arm ( 244 ) against blade ( 242 ). In yet another version, standoff yoke surface ( 318 ), described in greater detail below, may be disposed at a distal end of yoke ( 306 ) and include a lip that a proximal end of assembly ( 312 ) snaps over during insertion. Such insertion and structure would allow for a strong, proximal pull working against a weaker, distal push when assembly ( 312 ) is so attached to yoke ( 306 ). Other suitable ways in which clamp arm ( 244 ) may be actuated will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     A waveguide ( 320 ) is similar to waveguide ( 210 ) of transmission assembly ( 200 ) and is coaxially positioned within outer sheath ( 317 ) and within the internal tube. Waveguide ( 320 ) extends proximally relative to proximal end ( 310 ) of assembly ( 312 ) and couples with a transducer (not shown). 
     As the assembly ( 312 ) may be rotated, the waveguide could still be screwed into the transducer, as described above with respect to  FIGS. 3 and 4 , after the connection to yoke ( 306 ) is made. Once in position, proximal end ( 310 ) of assembly ( 312 ) sits flush against a standoff yoke surface ( 318 ). Standoff yoke surface ( 318 ) includes an opening for receipt of waveguide ( 320 ) of assembly ( 312 ). Standoff yoke surface ( 318 ) acts as a “setoff” for pushing on proximal end ( 310 ) of assembly ( 312 ) and allowing for a strong distal pushing force against assembly ( 312 ) and a concurrent less strong proximal pulling force. Closure of the clamp arm of the end effector of assembly ( 512 ) is then accomplished by pulling the inner tube of assembly ( 512 ) via yoke ( 306 ), against which proximal end ( 310 ) of assembly ( 312 ) sits flush via standoff yoke surface ( 318 ), allowing sufficient force to open the end effector and unclamp the end effector from tissue as described above. 
     When the end effector is opened, detents ( 314 ) pull on proximal end ( 310 ) of assembly ( 312 ) without disengaging from assembly ( 312 ). However, if a user wishes to replace assembly ( 312 ), the user may decouple detents ( 314 ) from assembly ( 312 ) by pulling hard enough to provide a sufficient force to remove assembly ( 312 ) from the reusable handle portion of instrument ( 50 A). 
     B. Exemplary Rotator Connections 
       FIGS. 7-12  show three versions of exemplary rotator connections to ultrasonic surgical instruments to provide for attachment and detachment of transmission assemblies to handle portions of the surgical instruments. The first version, shown in  FIGS. 7-9 , is directed to detents on a cylindrical portion of a rotator and a shaft connection method including a spring return. The second version, shown in  FIG. 10 , utilizes a shaft connection method including a retention ring. The third version, shown in  FIGS. 11  and  12 , utilizes a shaft connection method including a resiliently biasing clamping component in the form of multiple retention arms. 
     1. Exemplary Detent and Spring Return Version 
       FIG. 7  shows rotator ( 350 ) including knob portion ( 352 ) and proximal portion ( 354 ) transversely projecting from knob portion ( 352 ). Proximal portion ( 354 ) includes tabs ( 356 ) projecting from cylindrical portion ( 358 ). Rotator ( 350 ) includes longitudinal axis (A), which in  FIG. 7  divides rotator ( 350 ) into two portions.  FIG. 8  shows a fragmentary, perspective view of one of those portions. Tab ( 356 ) projects from the free end of resilient arm ( 360 ). 
       FIG. 9  shows a cross sectional view of rotator ( 350 ) as part of transmission assembly ( 362 ) inserted into distal end ( 364 ) of an ultrasonic surgical instrument. Assembly ( 362 ) includes a pair of stops ( 366 ) that capture a distal wall ( 370 ) of rotator ( 350 ). Distal wall ( 370 ) and other external walls of rotator ( 350 ) define an interior hollow space ( 372 ) through which inner tube ( 375 ) runs. Inner tube ( 375 ) translates within outer sheath ( 374 ). End piece ( 376 ) is fixedly disposed on a proximal end of inner tube ( 375 ) at a location aligned with a proximal end of cylindrical portion ( 358 ) when assembly ( 362 ) is fully inserted in distal end ( 364 ) of the instrument. A biasing member such as spring ( 378 ) is disposed between one of stops ( 366 ) and end piece ( 376 ). End piece ( 376 ) biases inner tube ( 375 ) to a proximal position, thereby biasing clamp arm ( 244 ) to a closed position (pivoted toward blade ( 242 )). 
     Additionally, when assembly ( 362 ) first inserted in distal end ( 364 ) of the instrument, tabs ( 356 ) compress inwards when against an aperture formed in distal end ( 364 ) which receives assembly ( 364 ). Cylindrical walls ( 380 ) defining the aperture end in ledges ( 382 ). When assembly ( 362 ) is fully inserted in distal end ( 364 ) of the instrument, tabs ( 356 ) clear cylindrical walls ( 380 ) and spring outward such than an upper surface of each tab ( 356 ) sits flush against ledges ( 382 ) to prevent undesired removal of assembly ( 362 ) from distal end ( 364 ). Rotator ( 350 ) may be removed thereafter by depressing tabs ( 356 ) by, for example, a user&#39;s fingers, to allow detents or tabs ( 356 ) to clear back through the aperture defined by walls ( 380 ). 
     A drive member ( 384 ) engages end piece ( 376 ) when assembly ( 362 ) is fully seated in the handpiece. Drive member ( 384 ) may be actuated via a yoke feature, in a manner as described above for surgical instrument ( 50 ), to compress spring ( 378 ) and push inner tube ( 375 ) distally in a manner closing a connected end effector (also as described above for instrument ( 50 )). Releasing the trigger releases spring ( 378 ) from a compressed state such that the biasing force of spring ( 378 ) drives inner tube ( 375 ) proximally and re-opens the clamped end effector (as described above). While the above described inner tube ( 375 ) is described as a clamp arm actuating tube for an ultrasonic surgical instrument ( 50 ), a similar inner member could be used as a firing beam for a radio frequency based surgical instrument or surgical stapling instrument (e.g., endocutter, etc.), including but not limited to variations of such instruments described in various references cited herein. 
     2. Exemplary Ring Version 
       FIG. 10  shows a manner of connecting end piece ( 376 ) of  FIG. 9  to drive member ( 384 ) of  FIG. 9 . Retention ring ( 404 ) is disposed in a groove at a proximal portion of end piece ( 376 ) between proximal end ( 406 ) and stop ( 408 ). Ring ( 404 ) helps to retain end piece ( 376 ) within drive member ( 384 ) while still allowing spring ( 378 ) disposed about inner tube ( 375 ) to return end piece ( 376 ) in the direction of arrow (B) to an initial, home position when a trigger on the instrument is not released. Ring ( 404 ) has a radial spring characteristic, allowing ring ( 404 ) to compress when end piece ( 376 ) is inserted into drive member ( 384 ). For instance, ring ( 404 ) may include a gap allowing the effective diameter of ring ( 404 ) to reduce as ring ( 404 ) is driven into first internal bore portion ( 412 ) of drive member ( 384 ), described below. 
     End piece ( 376 ) is inserted into drive member ( 384 ) in the direction of arrow (B). Drive member ( 384 ) includes first internal bore portion ( 412 ) disposed distal to second internal bore portion ( 414 ), which is narrower than portion ( 412 ) and separated from portion ( 412 ) via ledge ( 416 ), against which proximal end ( 406 ) will abut. First internal bore portion ( 412 ) of drive member ( 384 ) also includes annular groove ( 418 ) configured to receive ring ( 404 ). Ring ( 404 ) will have sufficient retention force to transmit force from spring ( 378 ) to return end piece ( 376 ) to the initial, home position, but such retention force may be overcome to remove end piece ( 376 ) from drive member ( 384 ) by pulling distally on transmission assembly ( 362 ). Alternatively, ring ( 404 ) may be positioned on a portion of the handle of the instrument rather than on end piece ( 376 ) to act as retention means against a groove in end piece ( 376 ). 
     3. Exemplary Retention Arms Version 
       FIGS. 11-12  show another manner of connecting another version of a shaft assembly ( 450 ), including outer sheath ( 451 ) with an internally translating inner tube ( 453 ), to drive member ( 452 ) via a resiliently biased clamping component ( 454 ). For example,  FIG. 12  shows a manner of connecting a version of inner tubular actuating member ( 220 ) to yoke ( 170 ) and force-limiting mechanism ( 180 ) of transmission assembly ( 70 ), where inner tube ( 453 ) is similar to inner tubular actuating member ( 220 ). Shaft assembly ( 450 ) may still be used with rotator ( 350 ) described above to retain the transmission assembly to the instrument. 
     Drive member ( 452 ) shown in  FIG. 11  includes groove ( 456 ) formed in distal end ( 458 ) of drive member ( 452 ). Groove ( 456 ) is configured to receive wedges ( 460 ) inwardly extending from retention arms ( 462 ) of component ( 454 ). Retention arms ( 462 ) are naturally or resiliently biased outward. Component ( 454 ) is disposed at proximal end ( 464 ) of inner tube ( 453 ) of shaft assembly ( 450 ). Component ( 454 ) may be molded in the described shape or could be a stamped metal, such as spring steel or other such suitable material. 
     When component ( 454 ) of inner tube ( 453 ) is inserted into circular recess ( 466 ) within distal end ( 468 ) of the handpiece (not shown) of the instrument in the direction of arrow (C), as shown in  FIG. 11 , shaft assembly ( 450 ) progresses until proximal end ( 470 ) abuts a surface on distal end ( 458 ) of drive member ( 452 ). At this point, proximal end ( 472 ) of rotator ( 350 A), which includes a proximal recess portion, will receive and clamp about distal end ( 474 ) of component ( 454 ). The internal walls defining the proximal recess portion of proximal end ( 472 ) of rotator ( 350 A) will continue to advance over retention arms ( 462 ) to compress arms ( 462 ) inwards until wedges ( 460 ) are received in groove ( 456 ), as shown in  FIG. 12 . Once rotator ( 350 A) is fully inserted into distal end ( 468 ) of the instrument, arms ( 462 ) cannot open outward to the natural position until rotator ( 350 A) is moved distally out of distal end ( 468 ) of the instrument, at which point arms ( 462 ) bias outward to their natural position to release drive member ( 452 ) from shaft assembly ( 450 ). One or more additional components may be provided to selectively secure rotator ( 350 A) to distal end ( 468 ) of the instrument. Various suitable forms that such components may take will be apparent to one of ordinary skill in the art in view of the teachings herein. 
     C. Exemplary Ball Bearing Compression Lock Connection 
       FIGS. 13-14  shows the connection of another transmission assembly ( 500 ) to handle portion ( 502 ) at distal end ( 504 ) of surgical instrument ( 50 C). Assembly ( 500 ) includes a rotation knob ( 506 ) into which shaft portion ( 508 ) comprising tubes that are part of a transmission assembly, such as transmission assembly ( 70 ) described above, connect. A difference is the ball bearing manner of connection of shaft portion ( 508 ) to knob ( 506 ). In particular, as shown in  FIG. 13 , drive member ( 510 ) is connected to inner tube ( 512 ) via ball bearings ( 514 ).  FIG. 14  shows inner tube ( 512 ) proximally progressing in the direction of arrow (D). Inner tube ( 512 ) includes inner circular walls ( 516 ) defining inner recess ( 518 ). An annular notch ( 520 ) is further defined in walls ( 516 ). Notch ( 520 ) is configured to receive ball bearings ( 514 ). 
     During assembly, waveguide ( 522 ) progresses in the direction of arrow (E) within both inner tube ( 512 ) and a recess within drive member ( 510 ). Waveguide ( 522 ) includes a tapered proximal end ( 524 ) such that when tapered end ( 524 ) progresses in the direction of arrow (E), ball bearings ( 514 ) engage with the tapered end ( 524 ) to ride up the widening ramped surface and are forced into engagement with notch ( 520 ) via a camming force applied by waveguide ( 522 ). The strong engagement allows for a high load fitting with reduced to no longitudinal slop. Further, inner tube ( 512 ) may still be rotated with respect to drive member ( 510 ). 
     Outer tube ( 526 ) and inner tube ( 512 ) connect to knob ( 506 ) via bayonet locks comprising a pin and slot type of fastening. For example, outer tube ( 526 ) ground locks into a recess ring boss (not shown) in rotation knob ( 506 ) to be fixed with respect to knob ( 506 ), which acts as a mechanical ground component. After the connection, the shaft components of transmission assembly ( 500 ) may rotate together and may still be removable from handle portion ( 502 ). Additionally, knob ( 506 ) of the present example is removably connected to handle portion ( 502 ). Inner tube ( 512 ) is similar to inner tubular actuating member ( 220 ) of transmission assembly ( 200 ). Inner tube ( 512 ) thus acts to drive a clamp arm to pivot relative to a blade, just like member ( 220 ) drives clamp arm ( 244 ) to pivot relative to blade ( 242 ) as described above. 
     D. Exemplary Tapered Waveguide Connection 
     In some versions, a waveguide may be attached to a transducer in a non-threaded connection to mate a transmission assembly with a reusable handle. For example,  FIG. 15  shows such a connection in an exemplary ultrasonic surgical instrument ( 50 D). Shaft assembly ( 550 ) includes shaft ( 552 ). Waveguide ( 554 ) extends from proximal end ( 556 ) of shaft ( 552 ). Waveguide ( 554 ) includes a male end feature ( 555 ). In the present example, male end feature ( 555 ) is tapered, though it should be understood that male end feature ( 555 ) may have various other suitable shapes and forms as will be apparent to one of ordinary skill in the art in view of the teachings herein, such as a flat form or a ball form, etc. Slip nut ( 558 ) is disposed around shaft ( 552 ). Slip nut ( 558 ) is configured to contact pin ( 560 ), which is attached at a longitudinal vibratory node of waveguide ( 554 ). Threaded cap or slip nut ( 558 ) presses against nodal pin ( 560 ) at the node and generates a compressive load to couple waveguide ( 554 ) to transducer ( 566 ) without utilizing a threaded connection between waveguide ( 554 ) and transducer ( 566 ), as described below. Additionally, slip nut ( 558 ) can act as a seal. A possible seal location is at notch ( 559 ) formed between distal end ( 561 ) and threads ( 563 ) of slip nut ( 558 ). 
     Slip nut ( 558 ) is also configured to be threaded into handle assembly ( 562 ) of instrument ( 50 D). The threaded connection forces end feature ( 555 ) of waveguide ( 554 ) into cavity ( 564 ), which is tapered in the present example and defined within the horn of transducer ( 566 ), along the direction of arrow (F). Cavity ( 564 ) may have various other suitable shapes and forms as will be apparent to one of ordinary skill in the art in view of the teachings herein, such as a flat form or a cone form for receipt of, for example, end feature ( 555 ) in a flat form or ball form, respectively. In particular, cavity ( 564 ) is configured to receive a correspondingly formed end feature ( 555 ). Spring mechanisms (not shown) in slip nut ( 558 ) or in transducer ( 566 ) may act to prevent too much force over the desired amount from being delivered to the connection of waveguide ( 554 ) and transducer ( 566 ). For example, in some versions, pin ( 560 ) may fit inside an inner diameter of slip nut ( 558 ), which would internally include a compression spring (not shown). A distal end of the compression spring would rest against a proximal part of a recess within slip nut ( 558 ). A drive plate (not shown) would be disposed at a proximal end of the compression spring. The drive plate would be configured to fit within the recess of slip nut ( 558 ). The drive plate would contact pin ( 560 ) and, via the compression spring, would limit force applied to pin ( 560 ). Other suitable force limiting features and configurations will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     Spring stack washer ( 570 ) is similar to force-limiting mechanism ( 180 ) of transmission assembly ( 70 ). Handle assembly ( 568 ) interfaces with spring stack washer ( 570 ) for actuation when trigger ( 572 ) is pressed, resulting in spring ( 573 ) to be compressed. This compression causes an inner tube of shaft ( 552 ) to be driven forward to close end effector ( 574 ) in a manner similar to that described above for instrument ( 50 ). In use, shaft assembly ( 550 ) is disposable and quickly able to be attached to a reusable handle of instrument ( 50 D). 
     It should be 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. 
     Versions of the devices described above may have application in conventional endoscopic and open surgical instrumentation as well as application in robotic-assisted surgery. For instance, those of ordinary skill in the art will recognize that various teaching herein may be readily combined with various teachings of U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with Ultrasound Cauterizing and Cutting Instrument,” published Aug. 31, 2004, the disclosure of which is incorporated by reference herein. 
     Versions of described above may be designed to be disposed of after a single use, or they can be designed to be used multiple times. Versions may, in either or both cases, be reconditioned for reuse after at least one use. Reconditioning may include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, some versions of the device may be disassembled, and any number of the particular pieces or parts of the device may be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, some versions of the device may be reassembled for subsequent use either at a reconditioning facility, or by a user immediately prior to a procedure. Those skilled in the art will appreciate that reconditioning of a device may utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     By way of example only, versions described herein may be sterilized before and/or after a procedure. In one sterilization technique, the device is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and device may then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation may kill bacteria on the device and in the container. The sterilized device may then be stored in the sterile container for later use. A device may also be sterilized using any other technique known in the art, including but not limited to beta or gamma radiation, ethylene oxide, or steam. 
     Having shown and described various versions in the present disclosure, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, versions, geometrics, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not required. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure and operation shown and described in the specification and drawings.