Features to couple acoustic drivetrain components in ultrasonic surgical instrument

#Ultrasonic surgical instruments utilize ultrasonic energy for both precise cutting and controlled coagulation of tissue. The ultrasonic energy cuts and coagulates by vibrating a blade in contact with the tissue. Vibrating at frequencies of approximately 50 kilohertz (kHz), for example, the ultrasonic blade denatures protein in the tissue to form a sticky coagulum. Pressure exerted on the tissue with the blade surface collapses blood vessels and allows the coagulum to form a hemostatic seal. The precision of cutting and coagulation may be controlled by the surgeon's technique and adjusting the power level, blade edge, tissue traction, and blade pressure, for example.

#Examples of ultrasonic surgical devices include the HARMONIC ACE® Ultrasonic Shears, the HARMONIC WAVE® Ultrasonic Shears, the HARMONIC FOCUS® Ultrasonic Shears, and the HARMONIC SYNERGY® Ultrasonic Blades, all by Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. Further examples of such devices and related concepts are disclosed in U.S. Pat. No. 5,322,055, entitled “Clamp Coagulator/Cutting System for Ultrasonic Surgical Instruments,” issued Jun. 21, 1994, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,873,873, entitled “Ultrasonic Clamp Coagulator Apparatus Having Improved Clamp Mechanism,” issued Feb. 23, 1999, the disclosure of which is incorporated by reference herein; 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; U.S. Pat. No. 6,283,981, entitled “Method of Balancing Asymmetric Ultrasonic Surgical Blades,” issued Sep. 4, 2001, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,309,400, entitled “Curved Ultrasonic Blade having a Trapezoidal Cross Section,” issued Oct. 30, 2001, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,325,811, entitled “Blades with Functional Balance Asymmetries for use with Ultrasonic Surgical Instruments,” issued Dec. 4, 2001, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,423,082, entitled “Ultrasonic Surgical Blade with Improved Cutting and Coagulation Features,” issued Jul. 23, 2002, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,773,444, entitled “Blades with Functional Balance Asymmetries for Use with Ultrasonic Surgical Instruments,” issued Aug. 10, 2004, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with Ultrasound Cauterizing and Cutting Instrument,” issued Aug. 31, 2004, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 8,057,498, entitled “Ultrasonic Surgical Instrument Blades,” issued Nov. 15, 2011, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 8,461,744, entitled “Rotating Transducer Mount for Ultrasonic Surgical Instruments,” issued Jun. 11, 2013, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 8,591,536, entitled “Ultrasonic Surgical Instrument Blades,” issued Nov. 26, 2013, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 8,623,027, entitled “Ergonomic Surgical Instruments,” issued Jan. 7, 2014, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 9,095,367, entitled “Flexible Harmonic Waveguides/Blades for Surgical Instruments,” issued Aug. 4, 2015, the disclosure of which is incorporated by reference herein; and U.S. Pub. No. 2016/0022305, entitled “Ultrasonic Blade Overmold,” published Jan. 28, 2016, issued as U.S. Pat. No. 9,750,521 on Sep. 5, 2017, the disclosure of which is incorporated by reference herein.

#An ultrasonic surgical instrument generally includes an ultrasonic transducer and an ultrasonic blade configured to be driven by the ultrasonic transducer. Various ultrasonic surgical instruments enable the ultrasonic blade to be selectively coupled with and decoupled from the ultrasonic transducer, via a threaded coupling between the two components. It is desirable to apply an appropriate amount of torque to this threaded coupling when assembling the blade with the transducer. Applying too much torque can cause the threaded coupling to fracture and fail during use, and applying too little torque can cause the threaded coupling to loosen and inhibit effective transmission of ultrasonic energy to tissue during use. Either result is undesirable, and can render the surgical instrument ineffective or entirely inoperable. Ultrasonic blades and transducers of conventional ultrasonic surgical instruments may be assembled with a hand-held torque wrench tool that is provided separately from the surgical instrument. The torque wrench tool includes features that limit application of additional torque to the threaded coupling between the ultrasonic blade and transducer once a predetermined amount of torque has been reached. An example of such a torque wrench tool is disclosed in U.S. Pat. No. 5,059,210, entitled “Apparatus and Methods for Attaching and Detaching an Ultrasonic Actuated Blade/Coupler and an Acoustical Mount Therefor,” issued Oct. 22, 1991, the disclosure of which is incorporated by reference herein.

#The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention.

#FIG. 1 depicts a perspective view of an exemplary ultrasonic surgical instrument;

#FIG. 2 depicts a perspective view of an end effector of the ultrasonic surgical instrument of FIG. 1;

#The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the invention 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 invention, and together with the description serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown.

#The following description of certain examples of the invention should not be used to limit the scope of the present invention. Other examples, features, aspects, embodiments, and advantages of the invention 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 invention. As will be realized, the invention is capable of other different and obvious aspects, all without departing from the invention. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.

#For clarity of disclosure, the terms “proximal” and “distal” are defined herein relative to a surgeon, or other operator, grasping a surgical instrument having a distal surgical end effector. The term “proximal” refers to the position of an element arranged closer to the surgeon, and the term “distal” refers to the position of an element arranged closer to the surgical end effector of the surgical instrument and further away from the surgeon. Moreover, to the extent that spatial terms such as “upper,” “lower,” “vertical,” “horizontal,” or the like are used herein with reference to the drawings, it will be appreciated that such terms are used for exemplary description purposes only and are not intended to be limiting or absolute. In that regard, it will be understood that surgical instruments such as those disclosed herein may be used in a variety of orientations and positions not limited to those shown and described herein.