Torsion limiting device and ultrasonic cutting hemostasis system

Abstract

The application provides an ultrasonic cutting hemostasis system and a torque limiting device thereof, the torque limiting device comprising a sleeve shaft for being connected with or integrated into a knife rod assembly and a rotating head sleeved on the sleeve shaft; one of the two is provided with a first tooth, and the other is provided with a first cantilever on a circumferential surface thereof towards the one, the first cantilever extending in an axial direction and forming an avoiding space with the circumferential surface, and a free end of the first cantilever is provided with a second tooth for being circumferentially engaged with the first tooth; when the rotating head drives the knife rod assembly to rotate in a screwing direction and beyond a critical torque relative to a transducer handle, the second tooth moves into the avoiding space to be disengaged from the first tooth and interrupt torque transmission. Thus, the application can ensure that the tightness of the threaded connection between the knife rod assembly and the transducer handle is moderate, and various design force value requirements can be met without increasing the radial space size of the rotating head, and the application has strong designability and practicability.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and specifically relates to a torque limiting device and an ultrasonic cutting hemostasis system. Background Technology

[0002] The ultrasonic cutting and hemostasis system includes a main unit, an ultrasonic scalpel, a transducer handle, and a foot pedal. The main unit and transducer handle are reusable, while the ultrasonic scalpel is disposable. Some ultrasonic scalpels can be used multiple times, but generally no more than 10 times. The scalpel's blade assembly and transducer handle are connected by threads. The ultrasonic vibrations generated by the transducer handle are transmitted through this threaded connection to the inner rod of the blade assembly, and then to the forceps head, thus achieving the ultrasonic scalpel's cutting and hemostasis functions.

[0003] The aforementioned threaded connection is a key factor in ensuring the stable operation of the ultrasonic cutting hemostasis system. A loose threaded connection will lead to unstable vibration transmission, preventing the ultrasonic cutting hemostasis system from vibrating at the desired operating frequency, thus failing to achieve the expected working effect. An overly tight connection will accelerate transducer thread damage and shorten the transducer's lifespan.

[0004] Therefore, ensuring that the threaded connection between the tool holder assembly and the transducer handle is of appropriate tightness is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a torque limiting device and an ultrasonic cutting hemostasis system that can ensure that the threaded connection between the cutter arm assembly and the transducer handle is of appropriate tightness.

[0006] To solve the above-mentioned technical problems, the present invention provides a torque limiting device for limiting the tightness of the threaded connection between the ultrasonic scalpel's shank assembly and the transducer handle. The torque limiting device includes a sleeve shaft and a rotating head.

[0007] The sleeve is used to connect to the tool holder assembly, or the sleeve is integrated into the tool holder assembly;

[0008] The rotating head is used to drive the sleeve shaft to rotate around the axis, and the rotating head is sleeved on the sleeve shaft;

[0009] One of the sleeve shaft and the rotating head is provided with a first tooth, and the other is provided with a first cantilever on the circumferential surface facing the first one. The first cantilever extends axially and forms a clearance space with the circumferential surface. The free end of the first cantilever is provided with a second tooth, and the second tooth and the first tooth are a pair of circumferential meshing teeth.

[0010] When the rotating head drives the tool holder assembly to rotate relative to the transducer handle in the spiral direction and exceeds the critical torque, the second tooth moves into the clearance space to slip out of the first tooth and interrupt the torque transmission;

[0011] When the rotating head drives the tool holder assembly to rotate relative to the transducer handle in the rotation direction, the first tooth and the second tooth mesh.

[0012] Optionally, the contact surface between the first tooth and the second tooth is a tooth profile surface, and the inclination of the tooth profile surface in the screwing direction is less than the inclination of the tooth profile surface in the screwing-out direction.

[0013] Optionally, the cross-section of the toothed surface is asymmetrical, either V-shaped or trapezoidal.

[0014] Optionally, the first tooth is a convex tooth and the second tooth is a concave tooth; or, the first tooth is a concave tooth and the second tooth is a convex tooth.

[0015] The number of concave teeth is an integer multiple of the number of convex teeth.

[0016] Optionally, the torque limiting device further includes an elastic washer disposed within the clearance space.

[0017] Optionally, the sleeve is mounted on the tool holder assembly via a pin.

[0018] Optionally, a protective sleeve is fitted onto the pin.

[0019] Optionally, an axial limiting mechanism is also provided between the rotating head and the sleeve shaft.

[0020] Optionally, the axial limiting mechanism includes:

[0021] An annular groove is provided on one of the rotating head and the sleeve shaft;

[0022] A cantilever buckle is provided on the other of the rotating head and the sleeve shaft, the cantilever buckle including a second cantilever and a fastening part provided on the free end of the second cantilever;

[0023] The fastening part is engaged in the annular groove, and there is a gap fit between the fastening part and the annular groove.

[0024] The present invention also provides an ultrasonic cutting hemostasis system, comprising:

[0025] An ultrasonic scalpel, comprising a scalpel arm assembly; and,

[0026] A transducer handle, which is threadedly connected to the tool holder assembly;

[0027] The ultrasonic scalpel also includes:

[0028] The torque limiting device described above is disposed on the tool holder assembly and is used to limit the tightness of the threaded connection between the tool holder assembly and the transducer handle.

[0029] The advantages of the torque limiting device provided by the present invention are as follows:

[0030] The torque limiting device has a first tooth on one of its sleeve shaft and rotating head, and a first cantilever on the circumferential surface of the other. The first cantilever extends axially and forms a clearance space with the circumferential surface. A second tooth is located at the free end of the first cantilever. During the rotation of the tool holder assembly via the rotating head, the first and second teeth mesh circumferentially, transmitting the torque applied to the rotating head by the operator to the inner rod of the tool holder assembly via tooth surface friction. The threaded end of the inner rod is then screwed onto the screw of the transducer handle, thus connecting the tool holder assembly and the transducer handle. When the thread is tightened to the design force, the torque required to be transmitted by the tooth surface exceeds the tooth surface friction, causing the second tooth to move into the clearance space. The second tooth slides relative to the first tooth, and the rotating head slips off the sleeve shaft, preventing further tightening of the thread. This ensures a suitable threaded connection tightness between the tool holder assembly and the transducer handle. Since the first cantilever extends axially, its extension length has virtually no impact on the radial spatial dimension of the rotating head. Therefore, in practical applications, the extension length (lever arm) of the first cantilever can be flexibly designed based on any given design force value. Thus, this torque limiting device can meet various design force requirements without increasing the radial spatial dimension of the rotating head (avoiding interference between the rotating head and the operating buttons in the operating handle), exhibiting strong designability and practicality.

[0031] The ultrasonic cutting hemostasis system provided by the present invention has the above-mentioned torque limiting device, and therefore also has the above-mentioned beneficial effects, which will not be repeated here. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an ultrasonic cutting hemostasis system provided in an embodiment of the present invention;

[0034] Figure 2A cross-sectional view of the assembly structure of the tool holder assembly, operating handle, transducer handle, and torque limiting device provided in an embodiment of the present invention;

[0035] Figure 3 for Figure 2 The assembly structure shown is a sectional view along the AA direction, where the related structures of the tool holder assembly are omitted;

[0036] Figure 4 A schematic diagram of a sleeve shaft provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of a rotating head provided in an embodiment of the present invention.

[0038] The reference numerals in the above figure include:

[0039] Main unit 100; ultrasonic scalpel 200; scalpel rod assembly 210; inner rod 211; middle sleeve 212; outer sleeve 213; operating handle 220; transducer handle 300; screw 310; foot pedal 400;

[0040] Torque limiting device 500; sleeve shaft 510; first tooth 511; rotating head 520; second tooth 521; rubber coating layer 522; elastic washer 530; pin shaft 540; protective sleeve 541; annular groove 551; cantilever buckle 552; screw in; screw out. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0043] In the description of this invention, "multiple" means two or more. If "first" and "second" are mentioned, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0044] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0045] The core of this invention is to provide a torque limiting device and an ultrasonic cutting hemostasis system, which can ensure that the threaded connection between the cutter arm assembly and the transducer handle is of appropriate tightness.

[0046] To enable those skilled in the art to better understand the technical solutions provided by the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Figure 1 This is a schematic diagram of an ultrasonic cutting hemostasis system provided in an embodiment of the present invention; specifically, please refer to... Figure 1 The ultrasonic cutting and hemostasis system includes: a main unit 100, an ultrasonic scalpel 200, a transducer handle 300, and a foot pedal 400.

[0048] The main unit 100 is communicatively connected to the transducer handle 300 and the foot pedal 400. The operator can input control signals to the main unit 100 through the foot pedal 400. Based on the received control signals, the main unit 100 can generate excitation signals and send them to the transducer handle 300 to excite the transducer handle 300 to generate mechanical vibration.

[0049] One end of the transducer handle 300 is provided with a screw 310, and the screw 310 is provided with an external thread for connecting with the ultrasonic scalpel 200.

[0050] The ultrasonic scalpel 200 includes a scalpel assembly 210 and an operating handle 220 for the operator to hold and input control signals. Specifically, as shown... Figure 2 As shown, the blade assembly 210 includes an inner rod 211, a middle sleeve 212, and an outer sleeve 213, which are sequentially sleeved from the inside out and are fixedly connected by a pin 540. The end of the inner rod 211 has an internal threaded hole, which can extend into the operating handle 220 and connect with the external thread on the screw 310 of the transducer handle 300. This allows the mechanical vibration generated by the transducer handle 300 to be transmitted from the proximal end (i.e., the end closer to the operator) to the distal end (i.e., the end farther from the operator) for ultrasonic cutting and / or hemostasis of tissue.

[0051] In particular, in this embodiment, the ultrasonic cutting hemostasis system also includes a torque limiting device 500 disposed on the blade assembly 210 and used to limit the tightness of the threaded connection between the blade assembly 210 and the transducer handle 300.

[0052] It should be understood that the core of this invention lies in the aforementioned torque limiting device 500. Therefore, the following embodiments of this invention will mainly focus on a detailed description of the torque limiting device 500. Other structures in the ultrasonic cutting hemostasis system provided in this embodiment can be found in relevant prior art and will not be described in detail here.

[0053] For details, please refer to Figure 2 and Figure 3 The torque limiting device 500 may include: a sleeve 510 and a rotating head 520. Wherein:

[0054] The sleeve 510 is used to connect to the tool holder assembly 210, or the sleeve 510 can be directly integrated into the tool holder assembly 210.

[0055] That is, in one specific embodiment, in order to facilitate production and reduce costs, the sleeve shaft 510 can be an independent component, which is fixedly connected to the tool holder assembly 210 and can drive the tool holder assembly 210 to rotate together. Specifically, the sleeve shaft 510 can be mounted on the tool holder assembly 210 via a pin 540 (that is, the inner rod 211, the middle sleeve 212, the outer sleeve 213, and the sleeve shaft 510 are simultaneously fixed via the pin 540). Further, a protective sleeve 541 can be fitted on the pin 540. The protective sleeve 541 can be an elastic element such as a silicone sleeve, which can play a role in anti-slip and vibration damping.

[0056] Alternatively, in another specific embodiment, to reduce the number of parts and the space occupied, the relevant structure of the sleeve shaft 510 can be directly integrated into the tool holder assembly 210. For example, the relevant structure of the sleeve shaft 510 can be formed on the outer sleeve 213 of the tool holder assembly 210. In this embodiment, that is, the outer sleeve 213 is used as the sleeve shaft 510. All improvements in the specific embodiments of this case are made on the outer sleeve 213, and the processing and modification are carried out on the outer sleeve 213 in actual production.

[0057] A rotating head 520 is sleeved on a sleeve shaft 510 and is used to drive the sleeve shaft 510 to rotate around the axis, thereby driving the inner rod 211 in the tool holder assembly 210 to rotate. The rotating head 520 and sleeve shaft 510 can be coaxially arranged with the inner rod 211, thus the axis can specifically be the central axis of the inner rod 211. Furthermore, the gripping area of ​​the rotating head 520 can be provided with a rubber coating 522. The rubber coating 522 is made of a softer material, which can improve the user experience.

[0058] Specifically, in this embodiment, the sleeve shaft 510 is provided with a first tooth 511, and the rotating head 520 is provided with a first cantilever on the circumferential surface facing the sleeve shaft 510. The first cantilever extends axially (that is, the first cantilever is parallel to the central axis of the tool holder assembly 210) and forms a clearance space with the circumferential surface. The free end of the first cantilever is provided with a second tooth 521, and the second tooth 521 and the first tooth 511 are a pair of circumferential meshing teeth.

[0059] When the tool holder assembly 210 is driven to rotate relative to the transducer handle 300 in the spiral direction by the rotating head 520 and the critical torque is exceeded, the second tooth 521 moves into the clearance space to slip off from the first tooth 511 and interrupt the torque transmission, thus forming a torque overload protection.

[0060] When the tool holder assembly 210 is driven to rotate relative to the transducer handle 300 in the rotation direction by the rotating head 520, the first tooth 511 and the second tooth 521 mesh.

[0061] It should be noted that the critical torque is a preset value, set to prevent damage to the threads caused by over-tightening of the tool holder assembly 210 and transducer handle 300. After determining the thread specification, the thread tightening torque is obtained with reference to national standards. The structure of the meshing gear pair is designed based on this torque value, so that the critical torque of the meshing gear pair is equal to or slightly greater than this value.

[0062] Furthermore, it is understood that in this embodiment, a first tooth 511 is provided on the outer peripheral surface of the sleeve shaft 510 (i.e., the peripheral surface facing the rotating head 520), and a first cantilever is provided on the inner peripheral surface of the rotating head 520 (i.e., the peripheral surface facing the sleeve shaft 510). The first cantilever extends axially and forms a clearance space with the inner peripheral surface of the rotating head 520. The free end of the first cantilever is provided with a second tooth 521. This is only for illustrative purposes. In some other embodiments, a first tooth may also be provided on the inner peripheral surface of the rotating head 520, and a first cantilever may be provided on the outer peripheral surface of the sleeve shaft 510. The first cantilever extends axially and forms a clearance space with the outer peripheral surface of the sleeve shaft 510. The free end of the first cantilever is provided with a second tooth.

[0063] In specific implementations, such as Figure 3 As shown, under the elastic force of the first cantilever, the first tooth 511 and the second tooth 521 are in a close engagement state. The contact surfaces of the first tooth 511 and the second tooth 521 are tooth profile surfaces, specifically including a first tooth surface M1 and a second tooth surface M2. The angle between the first tooth surface M1 and the perpendicular bisector is A1, and the angle between the second tooth surface M2 and the perpendicular bisector is A2. The sum of A1 and A2 is the included angle between the two tooth surfaces. Since A1 is less than A2, the inclination of the first tooth surface M1 is greater than the inclination of the second tooth surface M2. It can be understood that the greater the inclination of the tooth surfaces, the greater the acceptable rotational torque of the tooth pair.

[0064] In this embodiment, the second tooth surface M2 is set as the tooth profile surface in the advancing direction, and the first tooth surface M1 is set as the tooth profile surface in the exiting direction. Thus, the inclination of the tooth profile surface in the advancing direction is less than the inclination of the tooth profile surface in the exiting direction, thereby the acceptable rotational torque of the tooth pair in the advancing direction is less than its acceptable rotational torque in the exiting direction.

[0065] When the thread is screwed in, the second tooth surface M2 is the main force-bearing surface. Relying on the tooth surface friction, the torque applied by the operator to the rotating head 520 is transmitted to the tool holder assembly 210, thereby connecting the tool holder assembly 210 and the transducer handle 300. When tightened to the design force value, the torque required to be transmitted by the second tooth surface M2 is greater than the tooth surface friction, forcing the second tooth 521 to open outward and move into the clearance space. This causes the rotating head 520 to slip relative to the sleeve shaft 510, and the thread is no longer tightened further. The second tooth 521 passes over the previously engaged first tooth 511 and, under the action of the restoring force of the first cantilever, engages with the next adjacent first tooth 511, while simultaneously emitting a positioning sound.

[0066] After the surgery, when it is necessary to loosen the threaded connection between the scalpel assembly 210 and the transducer handle 300, the rotating head 520 is rotated in the opposite direction. At this time, the torque transmission surface is the first tooth surface M1. Since the tooth surface has a larger slope, it can transmit a larger torque. Therefore, the rotating head 520 and the sleeve shaft 510 can be used as a whole to drive the scalpel assembly 210 to loosen the threaded connection between the transducer handle 300 and the transducer handle.

[0067] Furthermore, the cross-section of the tooth profile can be asymmetrical, either V-shaped or trapezoidal. Specifically, V-shaped tooth profiles can withstand lower structural strength and are generally used for smaller critical torques. Trapezoidal tooth profiles, on the other hand, can withstand higher structural strength. The aforementioned V-shaped or trapezoidal tooth profiles are designed with two asymmetrical tooth surfaces with different inclinations on either side. Of course, the tooth profile can also be designed in other forms depending on the specific requirements.

[0068] Specifically, in this embodiment, such as Figure 4 and Figure 5 As shown, the first tooth 511 is a concave tooth, specifically a tooth-shaped groove provided on the outer circumferential surface of the sleeve shaft 510; the second tooth 521 is a convex tooth, specifically a tooth-shaped protrusion provided on the first cantilever. Of course, in some other embodiments, the first tooth 511 can also be a convex tooth and the second tooth 521 can be a concave tooth, as long as the first tooth 511 and the second tooth 521 can be circumferentially meshed.

[0069] In one case, the number of concave teeth equals the number of convex teeth. In another case, the number of concave teeth is an integer multiple of the number of convex teeth. This arrangement allows for the use of fewer convex teeth and a relatively larger number of concave teeth, thus reducing the circumferential rotation angle required to limit torque. Preferably, the number of convex teeth is 3-8.

[0070] Furthermore, in order to ensure that the tooth surfaces always maintain a tight fit, the torque limiting device 500 may also include an elastic washer 530, which is disposed in the clearance space to provide the resilience of the first cantilever so that the meshing tooth surfaces always maintain a tight fit.

[0071] For ease of production, the rotating head 520 and the sleeve 510 can be injection molded. However, the elastic restoring force provided by the first cantilever of the rotating head 520 formed in this way may not meet the design requirements. By adding the elastic washer 530, the reliability of the torque limiting device 500 can be improved. In addition, when the first cantilever breaks, the elastic washer 530 can keep the broken cantilever in its original position (i.e., the teeth are always engaged), preventing it from scattering in the clearance space.

[0072] The material and hardness of the elastic washer 530 can be selected according to the actual situation; specifically, it can be a rubber pad. The elastic washer 530 is an optional component; when the elasticity of the rotating head itself meets the design value, this component can be omitted.

[0073] Furthermore, to prevent the second tooth 521 from slipping off one of the first teeth 511 and engaging with the next adjacent first tooth 511 under the restoring force of the first cantilever, thus affecting the meshing effect, an axial limiting mechanism can be provided between the rotating head 520 and the sleeve shaft 510. This axial limiting mechanism can axially limit the rotating head 520 and the sleeve shaft 510, but does not restrict the rotational freedom of the rotating head 520 relative to the sleeve shaft 510.

[0074] Specifically, such as Figure 2 , 4 As shown in Figure 5, the axial limiting mechanism may include an annular groove 551 disposed on the sleeve shaft 510 and a cantilevered buckle 552 disposed on the rotating head 520. The cantilevered buckle 552 includes a second cantilever and a fastening portion disposed at the free end of the second cantilever. The fastening portion is used to engage in the annular groove when the rotating head 520 and the sleeve shaft 510 are assembled until the second tooth 521 engages with the first tooth 511, so as to axially position the rotating head 520 and the sleeve shaft 510. The fastening portion and the annular groove 551 are clearance-fitted to ensure that the axial limiting mechanism does not affect the relative rotation between the rotating head 520 and the sleeve shaft 510.

[0075] The second cantilever extends axially and forms a springback space with the inner circumferential surface of the rotating head 520. During assembly of the rotating head 520 and the sleeve 510, the engaging portion opens outward due to the deformation of the second cantilever and moves into the springback space. When the engaging portion reaches the annular groove, the interference between them is eliminated, and the engaging portion, under the restoring force of the second cantilever, engages into the annular groove. At this point, the second tooth 521 and the first tooth 511 are perfectly aligned.

[0076] In order to facilitate mold opening and assembly, the second cantilever can be set between two adjacent first cantilever.

[0077] Furthermore, it is understood that in some other embodiments, a cantilevered buckle may be provided on the sleeve shaft 510, and an annular groove may be provided on the rotating head 520.

[0078] Furthermore, in this embodiment, the operating handle 220 is provided with a mounting groove, which can be a U-shaped groove, and the sleeve 510 is provided with a positioning protrusion for engaging with the mounting groove. The mounting groove and the positioning protrusion engage to restrict the axial positioning and circumferential rotation of the sleeve 510 on the operating handle 220. The positioning protrusion and the mounting groove have a circumferential clearance, allowing the sleeve 510 to rotate circumferentially relative to the operating handle 220. In addition, the operating handle 220 includes two detachably connected housings, each housing having a slot and a buckle, and the two housings are fastened together.

[0079] Therefore, when assembling the ultrasonic scalpel 200, the rotating head 520 can first be fitted onto the outer circumference of the sleeve shaft 510 to complete the assembly of the torque limiting device 500; then, the sleeve shaft 510 and the scalpel assembly 210 are fixedly connected by the pin shaft 540 to set the torque limiting device 500 on the scalpel assembly 310; subsequently, the positioning protrusion of the sleeve shaft 510 is engaged in the assembly groove on one of the housings of the operating handle 220, and the scalpel assembly 210 is connected to other components (such as the clamping drive mechanism, etc.) in the operating handle 220; finally, the two housings of the operating handle 220 are fastened together, thereby completing the assembly of the ultrasonic scalpel 200.

[0080] As can be seen from the above, the main function of the rotating head 520 is to provide overload protection when the scalpel assembly 210 is threadedly connected to the transducer handle 300. However, it is understandable that it also has a rotation angle function, which can drive the scalpel assembly 210 and the forceps head set at the distal end of the scalpel assembly 210 to change the angle during the operation.

[0081] Specifically, during use, the first tooth 511 and the second tooth 521 are tightly engaged, and the force required to rotate the tool holder assembly 210 and the transducer handle 300 is small. Therefore, when the rotating head 520 is turned with a small force, the mating tooth surfaces between the rotating head 520 and the sleeve shaft 510 will not slip. Thus, the angle of the tool holder assembly 210 and the clamp head can be changed by turning the rotating head 520.

[0082] As can be seen from the above embodiments, the torque limiting device 500 provided by the present invention has a first tooth 511 on one of the sleeve shaft 510 and the rotating head 520, and a first cantilever on the circumferential surface of the other facing the first. The first cantilever extends axially and forms a clearance space with the circumferential surface. The free end of the first cantilever is provided with a second tooth 521. During the process of driving the tool bar assembly 210 to rotate through the rotating head 520, the first tooth 511 and the second tooth 521 mesh and drive in the circumferential direction. The torque applied by the operator to the rotating head 520 is transmitted to the inner rod 211 of the tool bar assembly 210 by relying on the friction of the tooth surface. The end of the inner rod 211 with internal thread is screwed into the screw 310 of the transducer handle 300, thereby connecting the tool bar assembly 210 and the transducer handle 300. When the thread is tightened to the design force value, the torque required to be transmitted by the tooth surface is greater than the frictional force of the tooth surface, causing the second tooth 521 to move into the clearance space. The second tooth 521 slides relative to the first tooth 511, and the rotating head 520 slips off the sleeve shaft 510. The thread is no longer tightened further, thus ensuring that the threaded connection between the tool holder assembly 210 and the transducer handle 300 has a moderate tightness. Since the first cantilever extends axially, its extension length has virtually no impact on the radial space dimension of the rotating head 520. Therefore, in practical applications, the extension length (lever arm) of the first cantilever can be flexibly designed based on any given design force value. Thus, the torque limiting device 500 can meet various design force requirements without increasing the radial space dimension of the rotating head 520 (avoiding interference between the rotating head 520 and the operating buttons on the operating handle 220), exhibiting strong designability and practicality.

[0083] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0084] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A torque limiting device (500) for limiting the tightness of a threaded connection between a blade shaft assembly (210) of an ultrasonic blade (200) and a transducer handle (300), characterized in that, The torsion limiting device (500) comprises a sleeve shaft (510) and a rotating head (520), wherein The sleeve shaft (510) is used for being connected with the cutter bar assembly (210), or the sleeve shaft (510) is integrated in the cutter bar assembly (210); The rotating head (520) is used for driving the sleeve shaft (510) to rotate around the shaft, and the rotating head (520) is sleeved on the sleeve shaft (510); One of the sleeve shaft (510) and the rotating head (520) is provided with first teeth (511), and the other is provided with a first cantilever on the peripheral surface of the one, the first cantilever extends in the axial direction and forms a clearance space with the peripheral surface, and the free end of the first cantilever is provided with second teeth (521), the second teeth (521) and the first teeth (511) are a pair of circumferential meshing teeth; When the rotating head (520) drives the cutter bar assembly (210) to rotate relative to the transducer handle (300) in the winding direction and exceeds the critical torque, the second teeth (521) move into the clearance space to slide off the first teeth (511) and interrupt the torque transmission; When the rotating head (520) drives the cutter bar assembly (210) to rotate relative to the transducer handle (300) in the unwinding direction, the first teeth (511) and the second teeth (521) are engaged; The contact surface of the first teeth (511) and the second teeth (521) is a tooth-shaped surface, and the inclination of the tooth-shaped surface in the winding direction is smaller than the inclination of the tooth-shaped surface in the unwinding direction; The torsion limiting device further comprises an elastic washer (530), and the elastic washer (530) is arranged in the clearance space.

2. The torsion limiting device (500) according to claim 1, characterized in that The cross section of the tooth-shaped surface is an asymmetric V-shaped or trapezoidal shape.

3. The torsion limiting device (500) according to claim 1, characterized in that The first teeth (511) are convex teeth, and the second teeth (521) are concave teeth; or, the first teeth (511) are concave teeth, and the second teeth (521) are convex teeth; The number of the concave teeth is an integer multiple of the number of the convex teeth.

4. The torsion limiting device (500) according to claim 1, characterized in that The sleeve shaft (510) is mounted on the cutter bar assembly (210) through a pin shaft (540).

5. The torsion limiting device (500) according to claim 4, characterized in that A protective sleeve (541) is sleeved on the pin shaft (540).

6. The torsion limiting device (500) according to any one of claims 1 to 5, characterized in that An axial limiting mechanism is further arranged between the rotating head (520) and the sleeve shaft (510).

7. The torsion limiting device (500) according to claim 6, characterized in that The axial limiting mechanism comprises: An annular groove (551) arranged on one of the rotating head (520) and the sleeve shaft (510); A cantilever buckle (552) arranged on the other of the rotating head (520) and the sleeve shaft (510), the cantilever buckle (552) comprises a second cantilever and a buckling part arranged at the free end of the second cantilever; The buckling part is arranged in the annular groove (551), and the buckling part and the annular groove (551) are gap-fitted.

8. An ultrasonic cutting hemostasis system characterized by, It comprises: An ultrasonic knife (200) comprising a cutter bar assembly (210); And, A transducer handle (300) threadedly connected with the cutter bar assembly (210); Wherein, the ultrasonic knife (200) further comprises: The torque limiting device (500) according to any one of claims 1 to 7, which is arranged on the cutter bar assembly (210) and used to limit the tightness of the threaded connection between the cutter bar assembly (210) and the transducer handle (300).

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