Motion conversion attachment for surgical tools

Abstract

An attachment for converting the rotational motion of a rotary surgical tool into the vibrational motion of a cutting accessory. The attachment comprises a housing that extends along the drive axis between a proximal and distal end and defines an internal cavity. The attachment further comprises an input shaft and an output shaft, each supported for rotation around the drive axis and at least partially located within the internal cavity. The attachment further comprises a crankshaft supported for rotation around a crankshaft and rotatably coupled to the input shaft. The crankshaft is perpendicular to the drive axis. The attachment further comprises a rocker shaft supported for rotation around a rocker shaft and rotatably coupled to the output shaft. The attachment further comprises an intermediate link coupled between the crankshaft and the rocker shaft.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This patent application claims the priority and all benefits of U.S. Provisional Patent Application No. 63 / 467,505, filed on May 18, 2023, the entire contents of which are incorporated herein by reference and made a part hereof.

Background Art

[0002] Conventional medical procedures routinely involve the use of surgical tools to assist medical professionals when accessing, visualizing, operating on, or otherwise treating a local surgical site. Some of these medical procedures may involve surgical techniques such as drilling, shaping, or decortication of bone using rotary instruments, where cutting accessories such as high - speed burrs rotate at speeds exceeding 75k rpm to remove tissue. During use, contact between the non - cutting portion (e.g., shank) of the burr and soft tissue can result in tissue wrapping, where the soft tissue is pulled around the shank by the friction between the rotating burr shank and the soft tissue. The surgeon must be careful to avoid unexpected tissue wrapping.

Summary of the Invention

[0003] In a first aspect, an attachment for a rotary surgical tool comprises a housing that extends along a drive shaft between a proximal end and a distal end and defines an internal cavity. The attachment further comprises an input shaft and an output shaft, each of which is supported for rotation about the drive shaft and is at least partially disposed within the internal cavity. The attachment further comprises a crankshaft that is supported for rotation about a crank axis and is rotationally coupled to the input shaft. The crank axis is perpendicular to the drive shaft. The attachment further comprises a rocker shaft that is supported for rotation about a rocker axis and is rotationally coupled to the output shaft. The attachment further comprises an intermediate link that is coupled between the crankshaft and the rocker shaft.

[0004] In a second embodiment, the attachment for a rotary surgical tool comprises a housing extending between a proximal and distal end and defining an internal cavity. The attachment further comprises an input shaft supported for rotation within the housing and having an input bevel gear located at the distal end of the input shaft. The attachment further comprises an output shaft supported for rotation within the housing and having an output bevel gear located at the proximal end of the output shaft. The attachment further comprises an oscillating linkage mechanism operably coupled between the input shaft and the output shaft. The oscillating linkage mechanism comprises a crankshaft, a rocker shaft, and an intermediate link. The crankshaft is supported for rotation around the crankshaft. The rocker shaft is supported for rotation around the rocker shaft. The intermediate link is coupled between the crankshaft and the rocker shaft and is configured to convert the rotational motion of the crankshaft into the oscillating motion of the rocker shaft. The oscillating linkage mechanism further comprises a crank bevel gear coupled to the crankshaft and engaging with the input bevel gear. The oscillating linkage mechanism further comprises a rocker bevel gear coupled to a rocker shaft and engaging with an output bevel gear.

[0005] In a third embodiment, an attachment for a rotary surgical tool comprises a housing assembly extending along a drive axis between a proximal and distal end. The housing assembly comprises a first housing body and a second housing body coupled to the first housing body in a central plane, which is parallel to the drive axis. An internal cavity is defined by the first and second housing bodies. The attachment further comprises an input shaft and an output shaft, each supported for rotation around the drive axis and at least partially located within the internal cavity. The attachment further comprises a crankshaft, a rocker shaft, and an intermediate link. The crankshaft is rotatably coupled to the input shaft. The rocker shaft is rotatably coupled to the output shaft. The intermediate link is coupled between the crankshaft and the rocker shaft and is arranged for cooperative motion along a plane parallel to the central plane.

[0006] In a fourth embodiment, the attachment for a rotary surgical tool comprises a housing extending between a proximal end and a distal end, defining an internal cavity. The attachment further comprises an input shaft, an output shaft, and an oscillatory linkage mechanism. The input shaft is supported for rotation within the housing. The output shaft is supported within the housing coaxially with the input shaft. The oscillatory linkage mechanism is operably coupled between the input shaft and the output shaft and is located within the internal cavity. The oscillatory linkage mechanism is configured to convert the rotational motion of the input shaft into the oscillatory motion of the output shaft.

[0007] In a fifth embodiment, the surgical bur system comprises a rotary surgical handpiece, a vibratory motion attachment, and a nose tube assembly. The rotary surgical handpiece comprises a motor, an attachment interface, and a motor shaft positioned within the attachment interface to supply rotational motion from the motor. The vibratory motion attachment is detachably coupled to the rotary surgical handpiece and comprises a housing extending between a proximal end and a distal end and configured to engage with the attachment interface. The vibratory motion attachment further comprises an input shaft supported for rotation within the housing and positioned to engage with the motor shaft when the housing engages with the attachment interface. The vibratory motion attachment further comprises an output shaft supported within the housing coaxially with the input shaft. The vibratory motion attachment further comprises a vibratory motion linkage mechanism operably coupled between the input shaft and the output shaft and positioned within an internal cavity. The vibratory motion linkage mechanism is configured to convert the rotational motion of the input shaft into the vibratory motion of the output shaft. The nose tube assembly is detachably coupled to the vibratory attachment on the opposite side of the rotary surgical handpiece. The nose tube assembly includes a drive shaft positioned to engage with the output shaft.

[0008] In a sixth embodiment, the attachment for a rotary surgical tool comprises a housing extending between a proximal end and a distal end. The housing defines an internal cavity. The attachment also comprises an input shaft supported for rotation along a first axis within the housing. The attachment also comprises an output shaft supported within the housing for rotation along a second axis within the housing intersecting the first axis. The attachment also comprises an oscillating link mechanism operably coupled between the input shaft and the output shaft and located within the internal cavity, the oscillating link mechanism being configured to convert the rotational motion of the input shaft into the oscillating motion of the output shaft.

[0009] In a seventh embodiment, a rotary surgical tool comprising a vibration conversion mechanism, an input shaft, and an output shaft includes a camshaft supported for rotation around a camshaft and configured to be coupled to the input shaft. The camshaft may comprise a proximal end configured to be coupled to the input shaft, a clockwise cam lobe, and a counterclockwise cam lobe axially separated from the clockwise cam lobe, the cam lobes configured to rotate in the same direction around the camshaft as the camshaft rotates around the camshaft. The tool also includes a rocker shaft supported for rotation around a rocker shaft and configured to be coupled to the output shaft, the rocker shaft being parallel to the camshaft. The rocker shaft may comprise a first cam follower that contacts the clockwise cam lobe to rotate the rocker shaft in a first direction around the rocker shaft, and a second cam follower that contacts the counterclockwise cam lobe axially separated from the first cam follower to rotate the rocker shaft in a second direction around the rocker shaft opposite to the first direction. The cam driveer alternately contacts the cam lobes to vibrate the rocker shaft.

[0010] Any of the above embodiments can be combined in whole or in part. Any of the features of any of the above embodiments can be combined in whole or in part. Any of the above implementations can be combined with any of the other embodiments.

[0011] The merits of this disclosure will be readily apparent as the disclosure is better understood by referring to the following detailed description, in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0012] [Figure 1] This is an oblique view of an exemplary surgical system used by a surgeon, showing the surgical system with surgical tools, attachments, nose tube assembly, and cutting accessories. [Figure 2] Figure 1 is a perspective view of surgical tools, attachments, nose tube assemblies, and cutting accessories. [Figure 3] Figure 1 is an exploded view of the surgical tool, attachment, nose tube assembly, and cutting accessory. [Figure 4] This is a cross-sectional view of the attachment and nose tube assembly along line 4-4 in Figure 5. [Figure 5] Another cross-sectional view of the attachment and nose tube assembly along line 5-5 in Figure 3. [Figure 6] Figures 4 and 5 are exploded views of the attachment and nose tube assembly, illustrating the vibration motion linkage mechanism. [Figure 7] Figure 6 is an exploded view of the attachment and vibration linkage mechanism, showing the crankshaft, rocker shaft, and intermediate link. [Figure 8] Figure 7 is an exploded view of the vibration-motion linkage mechanism, showing the crankshaft, rocker shaft, and intermediate link. [Figure 9] Figure 7 is an exploded view of the vibration-motion linkage mechanism, showing the crankshaft, rocker shaft, and intermediate link. [Figure 10] Figures 7 to 9 are simplified side views of the vibration-motion linkage mechanism, showing the crankshaft, rocker shaft, and intermediate link. [Figure 11] Figure 10 is a cross-sectional view of a simplified vibration motion linkage mechanism. [Figure 12] Exploded view of an oscillating link mechanism showing a rocker shaft, an intermediate link, and a crankshaft of a second embodiment. [Figure 13] Exploded view of an oscillating link mechanism showing a rocker shaft, an intermediate link, and a crankshaft of a second embodiment. [Figure 14] Perspective view of an oscillating link mechanism of a third embodiment. [Figure 15] Cross-sectional view of an oscillating link mechanism of a third embodiment. [Figure 16] Perspective view of an oscillating link mechanism of a fourth embodiment. [Figure 17] Cross-sectional view of an oscillating link mechanism of a fourth embodiment. [Figure 18] Cross-sectional view of an oscillating link mechanism of a fifth embodiment. [Figure 19] Perspective view of a second attachment provided with an oscillation conversion mechanism. [Figure 20] Cross-sectional view of a second attachment. [Figure 21] Perspective view of an oscillation conversion mechanism of a second attachment. [Figure 22] Exploded view of a rocker shaft of an oscillation conversion mechanism. [Figure 23] Perspective view of a camshaft of an oscillation conversion mechanism. [Figure 24] Side view of an oscillation conversion mechanism. [Figure 25A] Cross-sectional view of an oscillation conversion mechanism in a first orientation along line 25A-25A of FIG. 24. [Figure 25B] Cross-sectional view of an oscillation conversion mechanism in a first orientation along line 25B-25B of FIG. 24. [Figure 25C] Cross-sectional view of an oscillation conversion mechanism in a first orientation along line 25C-25C of FIG. 24. [Figure 26A] Cross-sectional view of an oscillation conversion mechanism in a second orientation along line 25A-25A of FIG. 24. [Figure 26B]This is a cross-sectional view of the vibration conversion mechanism in the second orientation along the line 25B-25B in Figure 24. [Figure 26C] This is a cross-sectional view of the vibration conversion mechanism in the second orientation along line 25C-25C in Figure 24. [Modes for carrying out the invention]

[0013] Referring here to the drawings (similar reference numerals indicate similar parts throughout several drawings), Figure 1 shows a surgical system 50. The surgical system 50 generally comprises surgical instruments 52, and in some embodiments, it may further comprise additional accessories that can be used with the surgical instruments 52. For example, the surgical system may further comprise an irrigation system (not shown), a navigation system (not shown), and so on. In the typical embodiments shown herein, the surgical instruments 52 are realized as surgical tools 54, more specifically, rotary surgical tools. The surgical system 50 may further comprise a console (not shown) that can be used to control the surgical instruments 52 via a foot switch. However, the surgical instruments 52 can be configured and controlled in several different ways. As a non-limiting example, the surgical instruments 52 may be controlled independently by a separate console or input device, etc.

[0014] Referring further to Figures 1 and 2, the surgical instrument 52 is generally configured as a rotary surgical tool 54 that drives a cutting accessory, shown in 56. Here, the cutting accessory 56 is adapted to assist medical professionals in performing surgical procedures by performing the removal of tissue, bone, etc. For this purpose, the cutting accessory 56 is depicted as a bar in Figures 1 to 5. Alternatively, the cutting accessory 56 can be several different types or configurations, such as a drill, shaver, rasp, or ultrasonic cutting tool.

[0015] Figure 2 shows a perspective view of a surgical instrument 52 in a first configuration. The surgical instrument 52 has a proximal end 58 and a distal end 60 spaced apart along the instrument axis A1. As used herein, “distal” generally refers to the part closer to the patient during use (e.g., a material removal tool), and “proximal” generally refers to the part further away from the patient during use (e.g., a power cord). Typically, the surgical instrument transmits mechanical energy from a power source (e.g., a motor or ultrasonic transducer) located near the proximal end along the instrument axis A1 to an attachment coupled to the distal end of the surgical instrument.

[0016] The surgical instrument 52 may comprise an attachment 100, a surgical handpiece 62 (or handpiece), a nose tube assembly 64, and a cutting accessory 56. The attachment 100 is configured to engage with the surgical handpiece 62 and receive the cutting accessory 56. The attachment 100 transmits rotational mechanical energy from the handpiece 62 to the cutting accessory 56. The handpiece 62 is powered and can receive electrical control signals from a control system coupled to the handpiece 62, for example, via a flexible supply cable 66.

[0017] The handpiece 62 may comprise a housing 68, a motor 70 located within the housing 68, a flexible supply cable 66 protruding from the housing 68 in the proximal region, and an attachment interface 72 located near the distal end of the housing 68. Exemplary surgical instruments can be found in U.S. Patent Nos. 8,597,316 and 10,537,339, which are incorporated herein by reference in their entirety.

[0018] The motor 70 generates rotational motion in the motor shaft 74, which is positioned within the attachment interface 72 to supply mechanical energy from the motor 70 to the cutting accessory 56 or attachment. As described above, the surgical instrument 52 may include a nose tube assembly 64, which can support the cutting accessory at its distal end. As shown in Figure 3, the cutting accessory 56 may include a head 76 and a shank 78 extending from the head 76. The shank 78 is adapted to be rotatably supported by the nose tube assembly 64 and is axially fixed to the attachment 100 via a tool chuck 80 (Figure 6). In relation to the exemplary cutting accessory 56 shown herein, the head 76 is realized as a bar, but as described above, it can be any suitable type or configuration (e.g., a drill).

[0019] In the exemplary surgical instrument 52 shown in Figures 1 to 3, the motor 70 is powered via a wired electrical connection to a console (not shown) and controlled via a foot switch, which is also electrically connected to the console. However, the surgical instrument 52 may be configured with or without a wired motor 70 controlled by a console. In a non-limiting example, the surgical instrument 52 may be powered by pneumatics or driven by a motor located within a console. Similarly, while a foot switch is used to control the motor 70 via the console, other types of user input are also conceivable. For example, a hand switch may be operably mounted on the housing 68 of the surgical instrument 52 to control the rotation of the motor 70, or the console may control the rotation of the motor 70 without a foot switch.

[0020] When removing tissue using the cutting accessory 56, airborne material may adhere to the shank 78, potentially causing tissue entanglement. Specifically, when the cutting accessory 56 and shank 78 are rotating at high rotational speeds, the flutes on the head 76 cause soft tissue to wrap around the shank 78, and surface friction with the shank 78 causes the soft tissue to adhere to the shank 78, resulting in tissue entanglement, which can damage the soft tissue and clog the nose tube assembly 64. Furthermore, tissue accumulation can reduce the surgeon's view of the surgical site. One way to reduce tissue entanglement is to modify the movement of the cutting accessory 56. Some types of cutting accessories and their associated movements are more prone to tissue entanglement than other cutting accessories with different movements. One type of cutting accessory 56 that tends to cause tissue entanglement is a rotary tool with a small diameter shank. Certain procedures require a tool with certain physical properties (e.g., shank diameter), so the movement of the cutting accessory is modified to reduce tissue entanglement. For example, another type of cutting accessory 56 is a vibratory cutting accessory, which vibrates or pivots around the tool axis. In one exemplary embodiment of the vibratory cutting accessory, the head 76 and shank 78 can vibrate between two positions separated by 180 degrees. In other words, the cutting accessory 56 has a vibratory motion of ±90 degrees. This reduces the possibility of trauma due to tissue entanglement during use. In some embodiments, the cutting accessory 56 can be optimized to different amounts of vibration based, for example, on the geometry of the head 76. Thus, the cutting accessory 56 can have vibratory motions in ranges of ±15 degrees, ±30 degrees, ±45 degrees, ±60 degrees, ±135 degrees, ±180 degrees, and other ranges not specifically listed.

[0021] As described above, certain procedures are advantageous when performed using instruments having a particular size, configuration, or form factor. For example, minimally invasive surgery is performed using instruments that are small in diameter and long in length. Since such instruments are typically handheld with a pen-like grip used by the surgeon, a consistent configuration of instruments with well-balanced weight is further advantageous. To provide a surgical instrument 52 that can implement the advantages described above, the surgical system 50 further comprises an attachment 100 that converts rotational motion into vibrational motion. The attachment 100 is detachably coupled to the handpiece 62 to operate with the attachment 100.

[0022] Several embodiments of the surgical instrument 52 may include a nose tube assembly 64 that is detachably coupled to the attachment 100. As will be described in more detail below, the nose tube assembly 64 may include a nose housing 84, a nose tube 86, and a drive shaft. The drive shaft is rotatable around the nose tube axis to transmit power from the handpiece 62 to the cutting accessory 56, the nose tube axis being shown herein as coaxial with the instrument axis A1. A tool chuck 80 is supported for rotation within the nose housing 84 and is configured to receive the cutting accessory 56, which is located at the working end of the surgical instrument 52. Here, the working end generally refers to the distal portion of the surgical instrument 52 intended to perform work (e.g., material removal) on a patient. The tool chuck 80 is operably coupled to the drive shaft to receive power from the handpiece 62. The nose housing 84 may include a threaded neck 90 at its proximal end, which is configured to detachably engage with the attachment 100. The distal end of the nose housing 84 is connected to the nose tube 86, which can be reduced in diameter to facilitate access to the surgical site.

[0023] In some embodiments, the nose tube assembly 64 can be angled with respect to the instrument axis A1. In other words, the nose tube axis is angled with respect to the instrument axis A1. Such a nose tube assembly can facilitate better control and / or visibility by the surgeon during use. For example, a surgeon may prefer the working end to be angled when performing a procedure with one type of cutting tool, while preferring the working end to be straight when performing a procedure with another type of cutting tool. The nose tube assembly 64 can be straight or angled at an angle such as 15 degrees, 45 degrees, etc. In addition, the nose tube 86 can be of various lengths such as 30 mm, 50 mm, etc.

[0024] As shown in Figures 3 to 5, power from the handpiece 62 is transmitted to the attachment 100 to drive the cutting accessory 56. The attachment 100 may comprise a housing 102 that extends along the drive shaft A2 between a proximal end 108 and a distal end 110, defining an internal cavity 104. The proximal end 108 of the attachment 100 is configured to engage with the handpiece 62. The housing 102 may comprise a bushing portion 112 located at the proximal end 108 of the housing 102 and engageable with the distal end of the handpiece 62. The bushing portion 112 is received by the handpiece 62 and is generally aligned with the instrument shaft A1. The bushing portion 112 has a first diameter 114 sized to engage with the attachment interface 72 of the handpiece 62. The housing 102 may further comprise a mounting flange 116 located distal to the bushing portion 112 and having a second diameter 118. The second diameter 118 of the mounting flange 116 is larger than the first diameter 114 of the bush portion 112. The second diameter 118 is sized to limit the insertion of the bush portion 112 into the handpiece 62. When the attachment 100 is fully coupled to the handpiece 62, the mounting flange 116 abuts against the distal end of the handpiece 62.

[0025] At the distal end 110 of the housing 102 opposite the bush portion 112, the housing further comprises an output portion 126 for engaging with the nose tube assembly 64. The nose tube assembly 64 is removably coupled to the attachment 100 at the distal end 110 of the housing 102. As best shown in Figure 6, the output portion 126 is implemented as a threaded socket 128, which is configured to receive the corresponding threaded neck 90 of the nose tube assembly 64.

[0026] The attachment 100 further comprises an input shaft 130, an output shaft 140, and an oscillatory linkage mechanism 150. The input shaft 130 and the output shaft 140 are each located at least partially within the internal cavity 104 at opposing ends of the housing 102 and supported for rotation. The input shaft 130 extends between a proximal end 132A and a distal end 132B and is supported for rotation within the housing 102. The output shaft 140 extends between a proximal end 142A and a distal end 142B and is supported for rotation within the housing 102. As will be described in more detail below, the oscillatory linkage mechanism 150 is operably coupled between the input shaft 130 and the output shaft 140. The distal end 132B of the input shaft 130 engages with the proximal end of the oscillatory linkage mechanism 150, and the distal end of the oscillatory linkage mechanism 150 engages with the proximal end 142A of the output shaft 140.

[0027] Corresponding gears can be coupled to the input shaft 130 and the output shaft 140, respectively, for operable engagement with the oscillating link mechanism 150. The input gear 134 and the output gear 144 are coupled to their respective shafts for rotation together. Specifically, the input gear 134 can be coupled to the distal end 132B of the input shaft 130, or adjacent to the distal end 132B of the input shaft 130. Similarly, the output gear 144 can be coupled to the proximal end 142A of the output shaft 140, or adjacent to the proximal end 142A of the output shaft 140. The corresponding gears and shafts can be coupled using interference fits, or fixed for rotation by set screws (not shown) screwed into the gears. Alternatively, a splined interface or other non-circular interface (e.g., a key) can be used to prevent relative rotation.

[0028] In the embodiments shown herein, the input gear 134 and output gear 144 are illustrated as bevel gears, but other types of gears such as helical bevel gears, hypoid gears, and crown gears can be used. Furthermore, the bevel gears are illustrated to have a pitch angle of 45 degrees so that power is transmitted perpendicularly to the corresponding input shaft 130 or output shaft 140. It is conceivable that other pitch angles can be used to achieve power transmission angles other than 90 degrees. In other words, the input shaft 130 and output shaft 140 are illustrated to be parallel to each other, and the oscillating motion link mechanism 150 can be configured to engage with input shaft 130 and output shaft 140 that are not parallel to each other. More specifically, the input shaft 130 and output shaft 140 are illustrated to be coaxial with each other and supported at least partially within the internal cavity 104 of the housing 102 for rotation around the drive shaft A2. One or more input bearings 136 can support the input shaft 130 within the housing 102. Similarly, one or more output bearings 146 can support the output shaft 140 within the housing 102.

[0029] Referring here to the exploded view of Figure 6, the attachment 100 is shown with the nose tube assembly 64 separated from the housing 102 and the vibratory motion link mechanism 150 removed from the housing 102. Here, the attachment 100 is shown with the output shaft subassembly 148 positioned between the nose tube assembly 64 and the vibratory motion link mechanism 150. The exemplary output shaft subassembly 148 shown herein comprises an output shaft 140, a tool chuck 80, an output bearing 146, and an output shaft housing 152. The output shaft housing 152 houses the output bearing 146 which supports the output shaft 140 for rotation around the drive shaft A2. The output shaft housing 152 has a threaded portion 154 configured to engage with a threaded socket 128 in the output portion 126 of the housing 102 to hold the output shaft 140 and the output gear 144 engaged with the vibratory motion link mechanism 150. Here, the tool chuck 80 is shown coupled to the output shaft 140 so as to transmit motion to the cutting accessory, which is positioned within the nose tube 86 and received within the tool chuck 80.

[0030] Figure 7 shows another exploded view with the housing 102 removed to illustrate the engagement between the vibratory motion linkage mechanism 150 and the input shaft 130 and output shaft 140, respectively. The vibratory motion linkage mechanism 150 may comprise a first housing body 156 and a second housing body 158 that cooperate to support the operation of the crankshaft 180 and rocker shaft 190, as will be discussed in more detail below. The first housing body 156 may be coupled to the second housing body 158 using fasteners 160 that clamp the first housing body 156 to the second housing body 158 and dowels 162 that facilitate precise alignment between the first housing body 156 and the second housing body 158. The first housing body 156 and the second housing body 158 are not identical, but are generally similar in that each has a mating surface 164 and their engagement defines a central plane 166. The first housing body 156 has a first mating surface 164A, and the second housing body 158 has a second mating surface 164B. When the first mating surface 164A engages with the second mating surface 164B to connect the first housing body 156 to the second housing body 158, a central plane 166 is defined between them. Furthermore, when the first housing body 156 is connected to the second housing body 158, an internal cavity 168 is defined within it. In the exemplary embodiments shown herein, the central plane 166 is parallel to the drive shaft A2, but other configurations are also conceivable. For example, in embodiments where the input shaft 130 and the output shaft 140 are non-parallel, the drive shaft A2 can be defined in a different way such that the central plane 166 and the drive shaft are non-parallel.

[0031] Each of the first housing body 156 and the second housing body 158 is provided with a pair of bearing seats 170, the first pair of bearing seats 170A being located on the first housing body 156 and the second pair of bearing seats 170B being located on the second housing body 158. As will be discussed below, the bearing seats 170 support the crank bearings 182 and the rocker bearings 192, which in turn support the crankshafts 180 and the rocker shafts 190 for their motion around their respective axes. The first pair of bearing seats 170A is located opposite the second pair of bearing seats 170B across the central plane 166 and defines axes perpendicular to the central plane 166 (crankshaft A3 and / or rocker shaft A4).

[0032] Referring here to Figures 7 to 9, further elements of the vibratory motion linkage mechanism 150 are shown. The vibratory motion linkage mechanism 150 comprises a crankshaft 180, a rocker shaft 190, and an intermediate link 200. The crankshaft 180 is supported for rotation around the crankshaft A3 and is rotatably coupled to the input shaft 130. Similarly, the rocker shaft 190 is supported for rotation around the rocker shaft A4 and is rotatably coupled to the output shaft 140. In the exemplary embodiment shown herein, the crankshaft A3 is parallel to the rocker shaft A4. As described above, the crankshaft 180 is supported within the internal cavity 168 by the first housing body 156 and the second housing body 158 on a crank bearing 182, and the crank bearing 182 is located in one of the bearing seats 170 within each of the first housing body 156 and the second housing body 158. Similarly, the rocker shaft 190 is supported within the internal cavity 168 by the first housing body 156 and the second housing body 158 on the rocker bearing 192, and the rocker bearing 192 is positioned in the other of the bearing seats 170 within the first housing body 156 and the second housing body 158, respectively.

[0033] The crankshaft 180 may comprise a first crank portion 184A and a second crank portion 184B, which are assembled to form the crankshaft 180. The crankshaft 180 further comprises an offset joint 186 axially separated from the crankshaft A3, which is coupled to an intermediate link 200. The first crank portion 184A can be assembled with the second crank portion 184B to form the offset joint 186 of the crankshaft 180. As will be discussed in more detail below, during operation, the offset joint 186 of the crankshaft 180 moves along a circular path around the crankshaft A3. For this purpose, the crankshaft 180 may further comprise a counterweight 188 radially opposed to the offset joint 186. More specifically, the counterweight 188 comprises a first counterweight 188A coupled to the first crank section 184A and a second counterweight 188B coupled to the second crank section 184B. During operation, the counterweight 188 dynamically balances the rotational mass of the offset joint 186 and the intermediate link 200 to reduce noise and vibration. Here, the first counterweight 188A and the second counterweight 188B are integrally formed with their respective crank sections 184A and 184B. In other embodiments (not shown), the counterweight may be coupled to the crankshaft using, for example, fasteners or interference fits.

[0034] The rocker shaft 190 may comprise a first rocker section 194A and a second rocker section 194B, which are assembled to form the rocker shaft 190. The rocker shaft 190 further comprises an offset joint 196 axially separated from the rocker shaft A4, which is coupled to an intermediate link 200. The first rocker section 194A can be assembled to the second rocker section 194B to form the rocker shaft 190. Unlike the crankshaft 180, the offset joint 196 of the rocker shaft 190 is a shaft that is assembled to the second rocker section 194B, for example, using an interference fit. During operation, as will be described in more detail below, the offset joint 196 of the rocker shaft 190 moves along an arc-shaped path aligned with the rocker shaft A4. For this purpose, the rocker shaft 190 may further comprise a counterweight 198 radially opposed to the offset joint 196. More specifically, the counterweight 198 is integrally formed with the second rocker section 194B. During operation, the counterweight 198 dynamically balances the rotational mass of the offset joint 196 and the intermediate link 200 to reduce noise and vibration. In other embodiments (not shown), the counterweight may be coupled to the rocker shaft using, for example, fasteners or interference fits.

[0035] As described above, the input shaft 130 is rotatably coupled to the crankshaft 180, and the output shaft 140 is rotatably coupled to the rocker shaft 190. The input gear 134 is coupled to the input shaft 130, and the output gear 144 is coupled to the output shaft 140. For this purpose, the crank gear 210 is coupled to the crankshaft 180 and engages with the input gear 134 to transmit rotational motion between them. Similarly, the rocker gear 212 is coupled to the rocker shaft 190 and engages with the output gear 144 to transmit rotational motion between them. As with the input gear 134 and the output gear 144 described above, the crank gear 210 and the rocker gear 212 can be bevel gears. In fact, in the exemplary embodiments shown herein, the crank gear 210 and the rocker gear 212 are bevel gears configured to transmit mechanical motion (rotation or vibration, respectively) together with the corresponding input gear 134 and the output gear 144.

[0036] As shown in Figures 5 and 10, the crank gear 210 is coupled to the first crank portion 184A of the crankshaft 180 and is located on the first side of the central plane 166. Similarly, the rocker gear 212 is coupled to the first rocker portion 194A of the rocker shaft 190 and is located on the first side of the central plane 166. The overall diameter of the attachment 100 can be reduced by reducing the height and width of the oscillating link mechanism having the input gear 134, crank gear 210, rocker gear 212, and output gear 144. Similarly, the speed ratio of the motor 70 and the cutting accessory 56 can be optimized. The ratio between the input gear 134 and the crank gear 210 is approximately 2:1, which reduces the speed of the crankshaft 180 relative to the input shaft 130. Similarly, the ratio between the rocker gear 212 and the output gear 144 is approximately 2:1, which doubles the amount of oscillating displacement (e.g., from ±45 degrees to ±90 degrees). Other embodiments of the vibration-motion linkage mechanism (not shown) can utilize ratios such as 1:1, 3:1, and 4:1. These ratios may have the effect of increasing or decreasing the relative rotational speed of the crankshaft 180 and the rocker shaft 190, as well as changing the associated stresses within the intermediate link 200.

[0037] Referring again to Figures 7 to 9, the intermediate link 200 is shown. The intermediate link 200 is coupled between the crankshaft 180 and the rocker shaft 190 and is configured to convert the rotational motion of the crankshaft 180 into the vibrational motion of the rocker shaft 190. The intermediate link 200 has two link eyes 202. The first link eye 202A is coupled to the offset joint 186 of the crankshaft 180, and the second link eye 202B is coupled to the offset joint 196 of the rocker shaft 190. During operation, the motion of the intermediate link 200 follows the motion of the rocker-crank type four-bar linkage mechanism. The rotation of the crankshaft 180 is converted into vibration of the rocker shaft 190. For this purpose, the intermediate link 200 moves in a plane 204 perpendicular to the crankshaft A3 and rocker shaft A4. The intermediate link 200 is positioned for cooperative motion along this plane 204, which is parallel to the central plane.

[0038] The size ratios of the crankshaft 180, rocker shaft 190, and intermediate link 200 are selected to optimize the transmission angle between the intermediate link 200 and the crankshaft 180 and rocker shaft 190, respectively, during operation, while maintaining a diameter similar to that of the handpiece 62. For example, the ratio of the crank stroke 214 to the rocker stroke 216 is approximately 1:2. The crank stroke 214 is the distance between the crankshaft A3 and the offset joint 186 of the crankshaft 180, and the rocker stroke 216 is the distance between the rocker shaft A4 and the offset joint 196 of the rocker shaft 190.

[0039] Referring here to Figures 12 and 13, exploded views of the vibratory linkage mechanism 150' of the second embodiment are shown. Specifically, the vibratory linkage mechanism 150' of the second embodiment includes a crankshaft 180' of the second embodiment. As will be understood from the following description, the second crankshaft 180' is the same as the crankshaft 180 described above in relation to Figures 1 to 11. Therefore, the components and structural features of the vibratory linkage mechanism 150' of the second embodiment that are the same as or otherwise corresponding to the vibratory linkage mechanism 150 of the first embodiment are given the same reference numerals with prime symbols (e.g., 180 and 180'). The specific differences between these embodiments will be described in detail, but for clarity, consistency, and brevity, only certain specific structural features and components common to these embodiments will be discussed and depicted in the drawings of the vibratory linkage mechanism 150' of the second embodiment. Herein, unless otherwise indicated, the above description of the vibratory motion link mechanism 150 of the first embodiment may be incorporated by reference with respect to the vibratory motion link mechanism 150' of the second embodiment, but is not limited thereto.

[0040] Similarly, the oscillating linkage mechanism 150' comprises a crankshaft 180', a rocker shaft 190', and an intermediate link 200'. The crankshaft 180' is supported for rotation around the crankshaft A3 and is rotatably coupled to the input shaft via an input gear 134'. Similarly, the rocker shaft 190' is supported for rotation around the rocker shaft A4 and is rotatably coupled to the output shaft via an output gear 144'. In the exemplary embodiment shown herein, the crankshaft A3 is parallel to the rocker shaft A4. As described above, the crankshaft 180' is supported within the internal cavity 168' by the first housing body 156' and the second housing body 158' on a crank bearing 182', and the crank bearing 182' is located in one of the bearing seats 170' within each of the first housing body 156' and the second housing body 158'. Similarly, the rocker shaft 190' is supported within the internal cavity 168' by the first housing body 156' and the second housing body 158' on the rocker bearing 192', and the rocker bearing 192' is positioned in the other of the bearing seats 170' within each of the first housing body 156' and the second housing body 158'.

[0041] Here, the crankshaft 180' of the second embodiment can be further defined as a crankshaft assembly 180'. The crankshaft assembly 180' may comprise a crank portion 184', a bearing 220', and a retainer 222' that, when assembled, form the crankshaft assembly 180'. The crank portion 184' has two journal portions 224' defining opposing ends of the crank portion 184', a counterweight portion 188', and an eccentric portion 226'. The journal portions 224' are each positioned within one of the crank bearings 182' to rotatably support the crankshaft assembly 180'. The eccentric portion 226' is axially separated from the crankshaft A3 and cooperates with the bearing 220' to form an offset joint 186'. The bearing 220' is assembled to the eccentric portion 226' to support an intermediate link 200' for cooperative motion around the crankshaft A3. As described above, during operation, the offset joint 186' of the crankshaft assembly 180' moves along a circular path around the crankshaft A3. The counterweight portion 188' of the crankshaft assembly 180' is adjacent to the eccentric portion 226' and is positioned radially opposite. The retainer 222' is adjacent to the bearing 220' and is coupled to the crank portion 184' on the opposite side from the counterweight portion 188'. In other words, the bearing 220' is positioned on the eccentric portion 226' between the counterweight portion 188' and the retainer 222'. The retainer 222' facilitates the alignment and holding of the bearing 220' within the link eye 202A' of the intermediate link 200' and the alignment and holding of the bearing 220' on the eccentric portion 226' of the crank portion 184'.

[0042] Referring here to Figures 14 and 15, exploded views of the vibratory linkage mechanism 150'' of the third embodiment are shown. Specifically, the vibratory linkage mechanism 150'' of the third embodiment comprises a crankshaft 180'' of the third embodiment. As will be understood from the following description, the third crankshaft 180'' is the same as the crankshaft 180 described above in relation to Figures 1 to 11. Therefore, the components and structural features of the vibratory linkage mechanism 150'' of the third embodiment, which are the same as or otherwise corresponding to the vibratory linkage mechanism 150'' of the first embodiment, are given the same reference numerals with a second prime symbol added (e.g., 180 and 180''). The specific differences between these embodiments will be described in detail, but for clarity, consistency, and brevity, only certain specific structural features and components common to these embodiments will be discussed and depicted in the drawings of the vibratory linkage mechanism 150'' of the third embodiment. Herein, unless otherwise indicated, the above description of the vibratory motion link mechanism 150 of the first embodiment may be incorporated by reference with respect to the vibratory motion link mechanism 150'' of the third embodiment, but is not limited thereto.

[0043] Similarly, the oscillating linkage mechanism 150'' comprises a crankshaft 180'', a rocker shaft 190'', and an intermediate link 200''. The crankshaft 180'' is supported for rotation around the crankshaft A3 and is rotatably coupled to the input shaft via an input gear 134''. Similarly, the rocker shaft 190'' is supported for rotation around the rocker shaft A4 and is rotatably coupled to the output shaft via an output gear 144''. In the exemplary embodiment shown herein, the crankshaft A3 is parallel to the rocker shaft A4. As described above, the crankshaft 180'' is supported within an internal cavity 168'' by a first housing body 156'' and a second housing body 158'' on a crank bearing 182'', and the crank bearing 182'' is located in one of the bearing seats 170'' within each of the first housing body 156'' and the second housing body 158''. Similarly, the rocker shaft 190'' is supported within the internal cavity 168'' by the first housing body 156'' and the second housing body 158'' on the rocker bearing 192'', and the rocker bearing 192'' is positioned in the other of the bearing seats 170'' within each of the first housing body 156'' and the second housing body 158''.

[0044] Here, the crankshaft 180'' of the third embodiment can be further defined as a crankshaft assembly 180''. The crankshaft assembly 180'' may comprise a first crank portion 184A'', a second crank portion 184B'', and a bearing 220'', which, when assembled, form the crankshaft assembly 180''. The first crank portion 184A'' and the second crank portion 184B'' can be joined together by fasteners 185'' such as set screws or grab screws. In other embodiments, the first crank portion 184A'' and the second crank portion 184B'' can be fixed together via an interference fit. Using multiple parts is advantageous in that it allows the eccentric portion to be positioned further away from the axis A3. The first crank portion 184A'' can be assembled with the second crank portion 184B'' to form an offset joint 186'' of the crankshaft 180''. The crank portion 184'' has two journal portions 224'' defining opposing ends of the crank portion 184'', a counterweight portion 188'', and an eccentric portion 226''. The journal portions 224'' are each positioned within one of the crank bearings 182'' to rotatably support the crankshaft assembly 180''. The eccentric portion 226'' is axially separated from the crankshaft A3 and cooperates with the bearing 220'' to form an offset joint 186''. The bearing 220'' is assembled to the eccentric portion 226'' to support the intermediate link 200'' for cooperative motion around the crankshaft A3. As described above, during operation, the offset joint 186'' of the crankshaft assembly 180'' moves along a circular path around the crankshaft A3. The counterweight portion 188'' of the crankshaft assembly 180'' is adjacent to the eccentric portion 226'' and is positioned radially opposite. It is also conceivable that the rocker shaft 190'' may comprise a first and a second portion that are joined together by fasteners in the same manner as described above for the crankshaft 180''.

[0045] Here, a third embodiment of the crank gear 210'' is coupled to the crankshaft 180'' and engages with the input gear 134'' to transmit rotational motion between them. Similarly, the rocker gear 212'' is coupled to the rocker shaft 190'' and engages with the output gear 144'' to transmit rotational motion between them. As with the input gear 134'' and output gear 144'' described above, the crank gear 210'' and the rocker gear 212'' can be bevel gears. In fact, in the exemplary embodiments shown herein, the crank gear 210'' and the rocker gear 212'' are bevel gears configured to transmit mechanical motion (rotation or vibration, respectively) together with the corresponding input gear 134'' and output gear 144''. The crank gear 210'' is configured to rotate continuously around the crankshaft A3, while the rocker gear 212'' is configured to vibrate such that the rocker gear 212'' does not rotate completely around the rocker shaft. In some embodiments, the rocker gear 212'' may include a partial bevel gear as shown in Figure 14. When the rocker gear 212'' includes a partial bevel gear, the rocker gear 212'' can accommodate a larger crank gear 210'' and reduce weight.

[0046] Referring here to Figures 16 and 17, exploded views of the vibratory linkage mechanism 150''' of the fourth embodiment are shown. Specifically, the vibratory linkage mechanism 150''' of the second embodiment includes the crankshaft 180''' of the fourth embodiment. As will be understood from the following description, the fourth crankshaft 180''' is similar to the crankshaft 180 described above in relation to Figures 1 to 11. Therefore, the components and structural features of the vibratory linkage mechanism 150''' of the fourth embodiment, which are the same as or otherwise corresponding to the vibratory linkage mechanism 150 of the first embodiment, are given the same reference numerals with a third prime symbol added (e.g., 180 and 180'''). The specific differences between these embodiments will be described in detail, but for clarity, consistency, and brevity, only certain specific structural features and components common to these embodiments will be discussed and depicted in the drawings of the vibratory linkage mechanism 150''' of the fourth embodiment. Herein, unless otherwise indicated, the above description of the vibratory motion link mechanism 150 of the first embodiment may be incorporated by reference with respect to the vibratory motion link mechanism 150'''' of the fourth embodiment, but is not limited thereto.

[0047] Similarly, the oscillating linkage mechanism 150''' comprises a crankshaft 180''', a rocker shaft 190''', and an intermediate link 200'''. The crankshaft 180''' is supported for rotation around the crankshaft A3 and is rotatably coupled to the input shaft via an input gear 134'''. Similarly, the rocker shaft 190''' is supported for rotation around the rocker shaft A4 and is rotatably coupled to the output shaft via an output gear 144'''. In the exemplary embodiment shown herein, the crankshaft A3 is parallel to the rocker shaft A4. As described above, the crankshaft 180''' is supported within an internal cavity 168''' by a first housing body 156''' and a second housing body 158''' on a crank bearing 182''', and the crank bearing 182''' is located in one of the bearing seats 170''' within each of the first housing body 156''' and the second housing body 158'''. Similarly, the rocker shaft 190''' is supported within the internal cavity 168''' by the first housing body 156''' and the second housing body 158''' on the rocker bearing 192''', and the rocker bearing 192''' is positioned in the other of the bearing seat 170''' within the first housing body 156''' and the second housing body 158'''.

[0048] Here, the crankshaft 180''' of the fourth embodiment can be further defined as a crankshaft assembly 180'''. The crankshaft assembly 180''' may comprise a crank portion 184''' and a bearing 220''' that, when assembled, form the crankshaft assembly 180'''. The crank portion 184''' has two journal portions 224''' defining opposing ends of the crank portion 184''', a counterweight portion 188''', and an eccentric portion 226'''. The journal portions 224''' are each positioned within one of the crank bearings 182''' to rotatably support the crankshaft assembly 180'''. The eccentric portion 226''' is axially separated from the crankshaft A3 and, in cooperation with the bearing 220''', forms an offset joint 186'''. In some embodiments, the crank portion 184''' may have a monolithic structure such that the journal portion 224''', the eccentric portion 226''', and the counterweight portion 188''' constitute a single component. It is also assumed that the rocker shaft 190''' may have a monolithic structure. The monolithic structure can provide greater rigidity in the shafts 180''', 190''' and can alleviate alignment concerns arising from the stacking of tolerances when using multiple components. The bearing 220''' is assembled to the eccentric portion 226''' to support the intermediate link 200''' for cooperative motion around the crankshaft A3. As described above, during operation, the offset joint 186''' of the crankshaft assembly 180''' moves along a circular path around the crankshaft A3. The counterweight portion 188''' of the crankshaft assembly 180''' is adjacent to the eccentric portion 226''' and is positioned radially opposite.

[0049] Here, the crank gear 210''' of the fourth embodiment is coupled to the crankshaft 180''' and engages with the input gear 134''' to transmit rotational motion between them. Similarly, the rocker gear 212''' is coupled to the rocker shaft 190''' and engages with the output gear 144''' to transmit rotational motion between them. As with the input gear 134''' and output gear 144''' described above, the crank gear 210''' and the rocker gear 212''' can be bevel gears. In fact, in the exemplary embodiments shown herein, the crank gear 210''' and the rocker gear 212''' are bevel gears configured to transmit mechanical motion (rotation or vibration, respectively) together with the corresponding input gear 134''' and output gear 144'''.

[0050] Referring now to Figure 18, an exploded view of the vibratory motion linkage mechanism 150'''' and attachment 100'''' of the fifth embodiment is shown. Specifically, the vibratory motion linkage mechanism 150'''' of the fifth embodiment comprises the crankshaft 180'''' of the fifth embodiment. As will be understood from the following description, the fifth crankshaft 180'''' is the same as the crankshaft 180 described above in relation to Figures 1 to 11. Therefore, the components and structural features of the vibratory motion linkage mechanism 150'''' and attachment 100'''' of the fifth embodiment, which are the same as or otherwise corresponding to the vibratory motion linkage mechanism 150 of the first embodiment, are given the same reference numerals with a fourth prime symbol added (e.g., 180 and 180''''). While the specific differences between these embodiments will be described in detail, for clarity, consistency, and brevity, only certain structural features and components common to these embodiments will be discussed and illustrated in the drawings of the fifth embodiment of the vibratory motion link mechanism 150''''. Herein, unless otherwise indicated, the above description of the vibratory motion link mechanism 150 and attachment 100 of the first embodiment may be incorporated by reference with respect to the vibratory motion link mechanism 150'''' and attachment 100'''' of the fifth embodiment, but is not limited thereto.

[0051] Similarly, the oscillating linkage mechanism 150'''' comprises a crankshaft 180'''', a rocker shaft 190'''', and an intermediate link. The crankshaft 180'''' is supported for rotation around the crankshaft A3 and is rotatably coupled to the input shaft 130'''' via an input gear 134''''. Similarly, the rocker shaft 190'''' is supported for rotation around the rocker shaft A4 and is rotatably coupled to the output shaft 140'''' via an output gear 144''''. In the exemplary embodiments shown herein, the crankshaft A3 is parallel to the rocker shaft A4.

[0052] Here, the crank gear 210'''' of the fifth embodiment is coupled to the crankshaft 180'''' and engages with the input gear 134'''' to transmit rotational motion between them. Similarly, the rocker gear 212'''' is coupled to the rocker shaft 190'''' and engages with the output gear 144'''' to transmit rotational motion between them. As with the input gear 134'''' and output gear 144'''' described above, the crank gear 210'''' and the rocker gear 212'''' can be bevel gears. In fact, in the exemplary embodiments shown herein, the crank gear 210'''' and the rocker gear 212'''' are bevel gears configured to transmit mechanical motion (rotation or vibration, respectively) together with the corresponding input gear 134'''' and output gear 144''''.

[0053] Here, the attachment 100'''' of the fifth embodiment is angled so that the input shaft 130'''' and the output shaft 140'''' do not rotate around the same axis. Furthermore, the bevel gear is illustrated having a pitch angle suitable for supporting a 45-degree power transmission angle. It is assumed that other pitch angles can be used to achieve power transmission angles other than 45 degrees. In other words, the input shaft 130'''' is configured to rotate around the tool shaft A1 when coupled to the motor housing. The output shaft 140'''' is configured to rotate around the drive shaft A2. The tool shaft A1 and the drive shaft A2 are not coaxial but intersect.

[0054] Another embodiment of the motion conversion attachment 300 is shown in Figures 19 to 26C. The attachment can be coupled to the handpiece 62 in the same manner as attachment 100 described above. Attachment 300 is also configured to support the nose tube assembly and cutting accessory, such as the nose tube assembly 64 and cutting accessory 56 described above. Similar to attachments 100, 100'''' and the vibratory motion linkage mechanisms 150, 150'', 150'''', 150'''' described above, attachment 300 transmits the rotational mechanical energy received from the handpiece 62, converts it into vibratory mechanical energy, and applies it to the cutting accessory 56.

[0055] The attachment 300 may comprise a housing 302 that extends along the drive shaft DX between its proximal and distal ends and defines an internal cavity. The attachment 300 may further comprise an input shaft 304 and an output shaft 306, each supported for rotation around the drive shaft DX and at least partially located within the internal cavity. The input shaft 304 is coupled to the motor of the handpiece 62 and configured to receive rotational energy from the motor of the handpiece 62. The output shaft 306 is configured to be coupled to the drive shaft of a cutting accessory 56 or a nose tube assembly 64, the drive shaft of the nose tube assembly 64 being coupled to the cutting accessory 56 to cause the cutting accessory 56 to vibrate. In some cases, the input shaft 304 and the output shaft 306 may be supported for rotation around separate axes that are not coaxial. In such cases, the axes around which the input shaft 304 and the output shaft 306 rotate may intersect.

[0056] The attachment 300 may further comprise a vibration conversion mechanism 308. The vibration conversion mechanism 308 comprises a camshaft 310 and a rocker shaft 312. The camshaft 310 is supported for rotation around the camshaft CX and is rotationally coupled to the input shaft 304 for continuous rotation around the camshaft CX. In the configuration shown in Figure 20, a gear assembly 314 is positioned between the input shaft 304 and the camshaft 310. The gear assembly 314 may include a planetary gear assembly to establish a speed reduction between the motor and the output shaft 306 so that the motor makes two or more rotations to produce a single vibration of the output shaft 306. The gear assembly 314 allows the attachment 300 to be used with a high-speed motor capable of rotating at speeds exceeding 75,000 rpm. In other configurations, the camshaft 310 is directly coupled to the input shaft 304. In yet another configuration, the camshaft 310 may comprise the input shaft 304 so that the camshaft 310 is directly connected to the handpiece 62. In the configurations shown in Figures 19 to 26C, the camshaft CX is coaxial with the drive shaft DX to reduce the overall size of the attachment 300. In other configurations, the camshaft CX and the drive shaft DX may not be coaxial. The rocker shaft 312 is supported for rotation around the rocker shaft RX and is rotationally coupled to the output shaft 306 to vibrate the output shaft 306. The rocker shaft RX and the camshaft CX are positioned parallel to each other.

[0057] The camshaft 310 may include an input section 316 for receiving torque from the input shaft 304. The camshaft 310 also includes a clockwise cam lobe 318 and a counterclockwise cam lobe 320 axially separated from the clockwise cam lobe 318. In the configuration shown in Figures 19 to 26C, the clockwise cam lobe 318 is positioned proximal to the counterclockwise cam lobe 320. It is assumed that the cam lobes 318 and 320 can be positioned in opposing directions. The cam lobes 318 and 320 are configured to orbit the camshaft 310 in the same direction relative to each other around the cam axis CX as the camshaft 310 rotates continuously around the cam axis CX. The external shapes of the cam lobes 318 and 320 are identical, and the arrangement of the cam lobes 318 and 320 can be in an opposing state. Each of the cam lobes 318, 320 has a convex surface 322a, 322b for engaging with the rocker shaft 312 and a concave surface 324a, 324b for allowing the rocker shaft 312 to be in a gaped state. The camshaft 310 may be equipped with a balancing mass 325 to balance the camshaft 310 during rotation around the camshaft CX. In some configurations, the cam lobes 318, 320 are spaced away from the camshaft CX such that no portion of the cam lobes 318, 320 intersects the camshaft CX during rotation of the camshaft 310 around the camshaft CX. By further spaced the cam lobes 318, 320 away from the camshaft CX, it is possible to help establish a large oscillation angle available on the output shaft 306.

[0058] The rocker shaft 312 includes a rocker member 326 configured to rotate around the rocker axis RX. The rocker shaft 312 further includes a first cam follower 328 extending from the rocker member 326 to abut against a clockwise cam lobe 318, and a second cam follower 330 axially separated from the first cam follower 328 and extending from the rocker member 326 to abut against a counterclockwise cam lobe 320. The rocker shaft 312 further includes spur gears 332 distal to the first cam follower 328 and the second cam follower 330 to engage with the pinion portion 334 of the output shaft 306. To reduce the overall size of the attachment 300, portions of the rocker shaft 312, such as the cam followers 328 and 330, can pass through the cam axis CX during rotation of the camshaft 310. Each of the cam followers 328 and 330 may be equipped with a needle bearing 336 for engaging with the cam lobes 318 and 320. The needle bearing 336 reduces friction and, consequently, heat generation between the rocker shaft 312 and the camshaft 310 by supporting rolling friction rather than sliding friction between the camshaft 310 and the rocker shaft 312.

[0059] During rotation, the cam lobes 318 and 320 alternately contact the first cam follower 328 and the second cam follower 330, respectively, to cause the rocker shaft 312 and the spur gear 332 to vibrate around the rocker shaft RX. More specifically, while the counterclockwise cam lobe 320 is in contact with the second cam follower 330, the clockwise cam lobe 318 does not contact the first cam follower 328, and while the clockwise cam lobe 318 is in contact with the first cam follower 328, the counterclockwise cam lobe 320 does not contact the second cam follower 330. In other words, the cam lobes 318 and 320 do not engage with their respective cam followers 328 and 330 simultaneously. During one rotation of the camshaft 310, the output shaft 306 can perform one complete vibration.

[0060] In one exemplary configuration, referring to Figures 24 to 26C, the positions of the cam lobes 318, 320, cam drivers 328, 330, and spur gear 332 during the rotation of the camshaft 310 are shown. As the camshaft 310 rotates in one direction around the camshaft CX, the convex surface 322a of the clockwise cam lobe 318 engages with the first cam driver 328, as shown in Figure 25A, causing the rocker shaft 312 to rotate counterclockwise. This engagement between the spur gear 332 and the output shaft 306 results in counterclockwise rotation of the output shaft 306. As shown in Figure 25B, while the convex surface 322a of the clockwise cam lobe 318 is engaged with the first cam follower 328, the concave surface 324b of the counterclockwise cam lobe 320 faces the second cam follower 330, creating a gap between them.

[0061] As the camshaft 310 rotates continuously in the same direction around the camshaft CX from the position shown in Figures 25A to 25C, the camshaft 310 rotates until the clockwise cam lobe 318 is separated from the first cam drive 328. After the clockwise cam lobe 318 is separated from the first cam drive 328, the convex surface 322b of the counterclockwise cam lobe 320 engages with the second cam drive 330, as shown in Figure 26B, causing the rocker shaft 312 to rotate clockwise. This engagement between the spur gear 332 and the output shaft 306 results in the output shaft 306 rotating counterclockwise in the opposite direction. As shown in Figure 26A, while the convex surface 322b of the counterclockwise cam lobe 320 is engaged with the second cam follower 330, the concave surface 324b of the clockwise cam lobe 318 faces the first cam follower 328, leaving a gap between them so that a gap is established between them.

[0062] The gap between the cam lobes 318, 320 and the cam followers 328, 330 during the transition from the engagement of one cam lobe 318, 320 to the engagement of the next cam lobe 318, 320 may be necessary to prevent binding and assist in assembly, but it is understood that the gap may be mitigated to reduce the possibility of chattering or vibration between components.

[0063] Several examples have been discussed in the above description. However, the embodiments discussed herein are not intended to be exhaustive or to limit this disclosure to any particular form. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of this disclosure. The terms used herein are intended to be descriptive, not restrictive. Many modifications and variations are possible in light of the above teachings, and this disclosure can be implemented in ways other than those specifically described.

[0064] item I. An attachment for a rotary surgical tool, comprising: a housing extending along a drive shaft between a proximal and distal end and defining an internal cavity; an input shaft and an output shaft, each supported for rotation around the drive shaft and at least partially located within the internal cavity; a crankshaft supported for rotation around a crankshaft and rotatably coupled to the input shaft, the crankshaft being perpendicular to the drive shaft; a rocker shaft supported for rotation around a rocker shaft and rotatably coupled to the output shaft; and an intermediate link coupled between the crankshaft and the rocker shaft.

[0065] II. The attachment described in item I, further comprising an input gear coupled to the distal end of an input shaft, and a crank gear coupled to a crankshaft and engaging with the input gear to transmit rotational motion between them.

[0066] III. The attachment described in item II, further comprising an output gear coupled to the proximal end of the output shaft, and a rocker gear coupled to a rocker shaft and engaging with the output gear to transmit rotational motion between them.

[0067] IV. The ratio between the input gear and the crank gear is approximately 2:1, and the ratio between the rocker gear and the output gear is approximately 2:1, as described in item III for the attachment.

[0068] V. Input gears, output gears, crank gears, and rocker gears are bevel gears, attachments as described in item III.

[0069] VI. The attachment described in item I, comprising a first housing body and a second housing body, the first housing body and the second housing body being joined in a central plane parallel to the drive shaft.

[0070] VII. The attachment described in item VI, further comprising an input gear coupled to the distal end of an input shaft, and a crank gear coupled to a crankshaft and engaging with the input gear to transmit rotational motion between them, wherein the crank gear is positioned on the crankshaft opposite to the intermediate link across a central plane.

[0071] VIII. The crankshaft has an offset joint axially separated from the crankshaft, and the first end of the intermediate link is coupled to the offset joint, as described in item I.

[0072] IX. The crankshaft is an attachment as described in item VIII, comprising a counterweight radially opposed to the offset joint.

[0073] X. The rocker shaft has an offset joint axially separated from the rocker shaft, and the second end of the intermediate link is coupled to the offset joint of the rocker shaft, as described in item VIII.

[0074] XI. The distance between the crankshaft and the offset joint of the crankshaft is further defined as the crank stroke, and the distance between the rocker shaft and the offset joint of the rocker shaft is further defined as the rocker stroke, and the ratio between the crank stroke and the rocker stroke is approximately 1:2, as described in item X of the attachment.

[0075] XII. The rocker shaft is the attachment described in item X, comprising a counterweight radially opposed to the offset joint of the rocker shaft.

[0076] XIII. An attachment for a rotary surgical tool, comprising: a housing extending between a proximal and distal end and defining an internal cavity; an input shaft supported for rotation within the housing and having an input bevel gear positioned at the distal end of the input shaft; an output shaft supported for rotation within the housing and having an output bevel gear positioned at the proximal end of the output shaft; and an oscillating motion linkage mechanism operably coupled between the input shaft and the output shaft, comprising: a crankshaft supported for rotation around a crankshaft; a rocker shaft supported for rotation around a rocker shaft; an intermediate link coupled between the crankshaft and the rocker shaft and configured to convert the rotational motion of the crankshaft into the oscillating motion of the rocker shaft; a crank bevel gear coupled to the crankshaft and engaging with the input bevel gear; and a rocker bevel gear coupled to the rocker shaft and engaging with the output bevel gear.

[0077] XIV. The attachment described in item XIII, comprising a first housing body and a second housing body, the first housing body and the second housing body being joined in a central plane perpendicular to the crankshaft.

[0078] XV. The input shaft rotates around the drive shaft, and the drive shaft is parallel to the central plane, as described in item XIV.

[0079] XVI. The crank bevel gear is an attachment described in item XIV, positioned on the crankshaft opposite the intermediate link, with the central plane in between.

[0080] XVII. The crankshaft has an offset joint axially separated from the crankshaft, and the first end of the intermediate link is coupled to the offset joint, as described in item XIII.

[0081] XVIII. The crankshaft is an attachment as described in item XVII, with a counterweight radially opposed from the offset joint.

[0082] XIX. The rocker shaft has an offset joint axially separated from the rocker shaft, and the second end of the intermediate link is coupled to the offset joint of the rocker shaft, as described in item XVII.

[0083] XX. The distance between the crankshaft and the offset joint of the crankshaft is further defined as the crank stroke, and the distance between the rocker shaft and the offset joint of the rocker shaft is further defined as the rocker stroke, and the ratio between the crank stroke and the rocker stroke is approximately 1:2, as described in item XIX of the attachment.

[0084] XXI. The rocker shaft is an attachment described in item XIX, which features a counterweight radially opposed to the offset joint of the rocker shaft.

[0085] XXII. Attachment for a rotary surgical tool, comprising a housing assembly extending along a drive axis between a proximal and distal end, comprising a first housing body, a second housing body coupled to the first housing body in a central plane, the central plane of which is parallel to the drive axis, and an internal cavity defined by the first and second housing bodies, and an input shaft and an output shaft, each supported for rotation around a drive axis and at least partially located within the internal cavity, a crankshaft rotatably coupled to the input shaft, a rocker shaft rotatably coupled to the output shaft, and an intermediate link coupled between the crankshaft and the rocker shaft and positioned for cooperative motion along a plane parallel to the central plane.

[0086] XXIII. The attachment described in item XXII, further comprising an input gear coupled to the distal end of an input shaft, and a crank gear coupled to a crankshaft and engaging with the input gear to transmit rotational motion between them.

[0087] XXIV. The crankshaft has an offset joint axially separated from the axis of rotation of the crankshaft, and the first end of the intermediate link is coupled to the offset joint, as described in item XXIII.

[0088] XXV. The crank gear is the attachment described in item XXIV, located on the crankshaft opposite the offset joint, with the central plane in between.

[0089] XXVI. The crankshaft is an attachment as described in item XXIV, comprising a counterweight radially opposed to the offset joint.

[0090] XXVII. The attachment described in item XXIV, further comprising an output gear coupled to the proximal end of an output shaft, and a rocker gear coupled to a rocker shaft, engaging with the output gear to transmit rotational motion between them.

[0091] XXVIII. The rocker shaft is equipped with an offset joint axially separated from the axis of rotation of the rocker shaft, and the second end of the intermediate link is coupled to the offset joint of the rocker shaft, as described in item XXVII.

[0092] XXIX. The rocker shaft is an attachment described in item XXVIII, comprising a counterweight radially opposed to the offset joint of the rocker shaft.

[0093] XXX. The rocker gear is the attachment described in item XXVIII, positioned on the rocker shaft opposite the offset joint of the rocker shaft, with the central plane in between.

[0094] XXXI. The distance between the axis of rotation of the crankshaft and the offset joint of the crankshaft is further defined as the crank stroke, and the distance between the axis of rotation of the rocker shaft and the offset joint of the rocker shaft is further defined as the rocker stroke, and the ratio between the crank stroke and the rocker stroke is approximately 1:2, as described in item XXVIII of the attachment.

[0095] XXXII. The ratio between the input gear and the crank gear is approximately 2:1, and the ratio between the rocker gear and the output gear is approximately 2:1, as described in item XXVII.

[0096] XXXIII. Input gears, output gears, crank gears, and rocker gears are bevel gears, attachments as described in item XXVII.

[0097] XXXIV. An attachment for a rotary surgical tool, comprising: a housing extending between a proximal end and a distal end and defining an internal cavity; an input shaft supported for rotation within the housing; an output shaft supported within the housing coaxially with the input shaft; and a vibratory motion link mechanism operably coupled between the input shaft and the output shaft and disposed within the internal cavity, the vibratory motion link mechanism being configured to convert the rotational motion of the input shaft into the vibratory motion of the output shaft.

[0098] XXXV. A surgical bur system comprising: a rotary surgical handpiece comprising a motor, an attachment interface, and a motor shaft disposed within the attachment interface to supply rotational motion from the motor; a vibratory motion attachment detachably coupled to the rotary surgical handpiece, comprising a housing extending between a proximal end and a distal end and configured to engage with the attachment interface, an input shaft supported for rotation within the housing and disposed to engage with the motor shaft when the housing engages with the attachment interface, an output shaft supported within the housing coaxially with the input shaft, and a vibratory motion link mechanism operably coupled between the input shaft and the output shaft and disposed within an internal cavity, the vibratory motion link mechanism being configured to convert rotational motion of the input shaft into vibratory motion of the output shaft; and a nose tube assembly detachably coupled to the vibratory motion attachment on the opposite side of the rotary surgical handpiece, comprising a drive shaft disposed to engage with the output shaft.

Claims

1. An attachment for rotary surgical tools, A housing that extends along the drive shaft between the proximal and distal ends and defines an internal cavity, An input shaft and an output shaft, each supported for rotation around the drive shaft and at least partially located within the internal cavity, A crankshaft supported for rotation around a crankshaft and rotatably coupled to the input shaft, wherein the crankshaft is perpendicular to the drive shaft, A rocker shaft supported for rotation around the rocker shaft and rotatably coupled to the output shaft, An intermediate link connected between the crankshaft and the rocker shaft, An attachment equipped with [a certain feature].

2. An input gear coupled to the distal end of the input shaft, A crank gear coupled to the crankshaft and engaging with the input gear to transmit rotational motion between them, The attachment according to claim 1, further comprising the following:

3. An output gear coupled to the proximal end of the output shaft, A rocker gear coupled to the rocker shaft and engaging with the output gear to transmit rotational motion between them, The attachment according to claim 2, further comprising the following:

4. The attachment according to claim 3, wherein the ratio between the input gear and the crank gear is approximately 2:1, and the ratio between the rocker gear and the output gear is approximately 2:

1.

5. The attachment according to claim 3, wherein the input gear, the output gear, the crank gear, and the rocker gear are bevel gears.

6. The attachment according to claim 1, wherein the housing comprises a first housing body and a second housing body, and the first housing body and the second housing body are joined in a central plane parallel to the drive shaft.

7. An input gear coupled to the distal end of the input shaft, A crank gear coupled to the crankshaft and engaging with the input gear to transmit rotational motion between them, wherein the crank gear is positioned on the crankshaft opposite to the intermediate link across the central plane, The attachment according to claim 6, further comprising the following:

8. The attachment according to claim 1, wherein the crankshaft comprises an offset joint axially separated from the crankshaft, and the first end of the intermediate link is coupled to the offset joint.

9. The attachment according to claim 8, wherein the crankshaft is provided with a counterweight radially opposed to the offset joint.

10. The attachment according to claim 8, wherein the rocker shaft comprises an offset joint axially separated from the rocker shaft, and the second end of the intermediate link is coupled to the offset joint of the rocker shaft.

11. The attachment according to claim 10, wherein the distance between the crankshaft and the offset joint of the crankshaft is further defined as the crank stroke, the distance between the rocker shaft and the offset joint of the rocker shaft is further defined as the rocker stroke, and the ratio between the crank stroke and the rocker stroke is about 1:

2.

12. The attachment according to claim 10, wherein the rocker shaft is provided with a counterweight radially opposed to the offset joint of the rocker shaft.

13. An attachment for rotary surgical tools, A housing extending between the proximal and distal ends, defining the internal cavity, An input shaft having an input bevel gear that is supported for rotation within the housing and positioned at the distal end of the input shaft, An output shaft having an output bevel gear positioned at the proximal end of the output shaft, which is supported for rotation within the housing A vibration motion link mechanism operably coupled between the input shaft and the output shaft, A crankshaft supported for rotation around the crank axis, A rocker shaft supported for rotation around the rocker axis, An intermediate link is coupled between the crankshaft and the rocker shaft and configured to convert the rotational motion of the crankshaft into the vibrational motion of the rocker shaft, A crank bevel gear coupled to the crankshaft and engaging with the input bevel gear, A rocker bevel gear coupled to the rocker shaft and engaging with the output bevel gear, A vibration motion link mechanism, An attachment equipped with [a certain feature].

14. The attachment according to claim 13, wherein the housing comprises a first housing body and a second housing body, and the first housing body and the second housing body are joined in a central plane perpendicular to the crankshaft.

15. The attachment according to claim 14, wherein the input shaft rotates around the drive shaft, and the drive shaft is parallel to the central plane.

16. The attachment according to claim 14, wherein the crank bevel gear is arranged on the crankshaft opposite to the intermediate link, with the central plane in between.

17. The attachment according to claim 13, wherein the crankshaft comprises an offset joint axially separated from the crankshaft, and the first end of the intermediate link is coupled to the offset joint.

18. The attachment according to claim 17, wherein the crankshaft is provided with a counterweight radially opposed to the offset joint.

19. The attachment according to claim 17, wherein the rocker shaft comprises an offset joint axially separated from the rocker shaft, and the second end of the intermediate link is coupled to the offset joint of the rocker shaft.

20. The attachment according to claim 19, wherein the distance between the crankshaft and the offset joint of the crankshaft is further defined as the crank stroke, the distance between the rocker shaft and the offset joint of the rocker shaft is further defined as the rocker stroke, and the ratio between the crank stroke and the rocker stroke is about 1:

2.

21. The attachment according to claim 19, wherein the rocker shaft is provided with a counterweight radially opposed to the offset joint of the rocker shaft.

22. An attachment for rotary surgical tools, A housing assembly extending along the drive shaft between a proximal end and a distal end, The first housing body, A second housing body coupled to the first housing body in a central plane, wherein the central plane is parallel to the drive shaft, The internal cavity defined by the first housing body and the second housing body, A housing assembly comprising, An input shaft and an output shaft, each supported for rotation around the drive shaft and at least partially located within the internal cavity, A crankshaft that is rotationally coupled to the input shaft, A rocker shaft is rotatably coupled to the output shaft, An intermediate link is coupled between the crankshaft and the rocker shaft and is positioned for cooperative motion along a plane parallel to the central plane, An attachment equipped with [a certain feature].

23. An input gear coupled to the distal end of the input shaft, A crank gear coupled to the crankshaft and engaging with the input gear to transmit rotational motion between them, The attachment according to claim 22, further comprising the above.

24. The attachment according to claim 23, wherein the crankshaft comprises an offset joint axially separated from the rotation axis of the crankshaft, and the first end of the intermediate link is coupled to the offset joint.

25. The attachment according to claim 24, wherein the crank gear is arranged on the crankshaft opposite to the offset joint, with the central plane in between.

26. The attachment according to claim 24, wherein the crankshaft is provided with a counterweight radially opposed to the offset joint.

27. An output gear coupled to the proximal end of the output shaft, A rocker gear coupled to the rocker shaft and engaging with the output gear to transmit rotational motion between them, The attachment according to claim 24, further comprising the above.

28. The attachment according to claim 27, wherein the rocker shaft comprises an offset joint axially separated from the rotation axis of the rocker shaft, and the second end of the intermediate link is coupled to the offset joint of the rocker shaft.

29. The attachment according to claim 28, wherein the rocker shaft is provided with a counterweight radially opposed to the offset joint of the rocker shaft.

30. The attachment according to claim 28, wherein the rocker gear is arranged on the rocker shaft opposite to the offset joint of the rocker shaft, with the central plane in between.

31. The attachment according to claim 28, wherein the distance between the rotation axis of the crankshaft and the offset joint of the crankshaft is further defined as the crank stroke, and the distance between the rotation axis of the rocker shaft and the offset joint of the rocker shaft is further defined as the rocker stroke, and the ratio between the crank stroke and the rocker stroke is about 1:

2.

32. The attachment according to claim 27, wherein the ratio between the input gear and the crank gear is approximately 2:1, and the ratio between the rocker gear and the output gear is approximately 2:

1.

33. The attachment according to claim 27, wherein the input gear, the output gear, the crank gear, and the rocker gear are bevel gears.

34. An attachment for rotary surgical tools, A housing extending between the proximal and distal ends, defining the internal cavity, An input shaft supported for rotation within the housing, The output shaft is supported coaxially with the input shaft and within the housing, A vibration-motion link mechanism operably coupled between the input shaft and the output shaft and disposed within the internal cavity, wherein the vibration-motion link mechanism is configured to convert the rotational motion of the input shaft into vibrational motion of the output shaft, An attachment equipped with [a certain feature].

35. An attachment for rotary surgical tools, A housing extending between the proximal and distal ends, defining the internal cavity, An input shaft supported for rotation along a first axis within the housing, An output shaft supported within the housing, which is supported for rotation along a second axis within the housing that intersects the first axis, A vibration-motion link mechanism operably coupled between the input shaft and the output shaft and disposed within the internal cavity, wherein the vibration-motion link mechanism is configured to convert the rotational motion of the input shaft into vibrational motion of the output shaft, An attachment equipped with [a certain feature].

36. The crankshaft comprises a monolithic structure, as described in any one of claims 1 to 35.

37. The rocker shaft is an attachment according to any one of claims 1 to 36, wherein the rocker shaft has a monolithic structure.

38. The attachment according to any one of claims 1 to 37, wherein the crankshaft comprises a first portion and a second portion that are joined together via a fastener.

39. The attachment according to any one of claims 1 to 38, further comprising a bearing disposed between at least one of the crankshaft and the rocker shaft and the intermediate link.

40. The attachment according to any one of claims 1 to 39, wherein the rocker gear includes a partial bevel gear.

41. A surgical bur system, A rotary surgical handpiece comprising a motor, an attachment interface, and a motor shaft positioned within the attachment interface to supply rotational motion from the motor, A vibratory motion attachment that can be detachably coupled to the rotary surgical handpiece, A housing extending between the proximal and distal ends and configured to engage with the attachment interface, An input shaft, supported for rotation within the housing and positioned to engage with the motor shaft when the housing engages with the attachment interface, The output shaft is supported coaxially with the input shaft and within the housing, A vibration-motion link mechanism operably coupled between the input shaft and the output shaft and disposed within the internal cavity, wherein the vibration-motion link mechanism is configured to convert the rotational motion of the input shaft into vibrational motion of the output shaft, A vibratory motion attachment equipped with, A nose tube assembly that is removably coupled to the vibratory attachment on the opposite side of the rotary surgical handpiece, comprising a drive shaft positioned to engage with the output shaft, A surgical bur system equipped with [specific features / features].

42. The surgical bar system according to claim 41, wherein the crankshaft has a monolithic structure.

43. The surgical bur system according to claim 41 or 42, wherein the rocker shaft has a monolithic structure.

44. The surgical bar system according to any one of claims 41 to 43, wherein the crankshaft comprises a first portion and a second portion that are joined together via a fastener.

45. The surgical bar system according to any one of claims 41 to 44, further comprising a bearing disposed between at least one of the crankshaft and the rocker shaft and the intermediate link.

46. The surgical bur system according to any one of claims 41 to 45, wherein the rocker gear is a partial bevel gear.

47. A rotary surgical tool comprising a vibration conversion mechanism, an input shaft, and an output shaft, A camshaft that is supported for rotation around a camshaft and is configured to be coupled to the input shaft, A proximal end configured to be coupled to the input shaft, Clockwise cam lobe and, A counterclockwise cam lobe is axially separated from the aforementioned clockwise cam lobe, Equipped with, The cam lobe is configured to rotate in the same direction around the cam shaft as the cam shaft rotates around the cam shaft. Camshaft and A rocker shaft is supported for rotation around a rocker shaft and configured to be coupled to the output shaft, wherein the rocker shaft is parallel to the camshaft, and the rocker shaft is A first cam drive that contacts the clockwise cam lobe and rotates the rocker shaft in a first direction around the rocker axis, A second cam drive is axially separated from the first cam drive and contacts the counterclockwise cam lobe, causing the rocker shaft to rotate in a second direction around the rocker shaft opposite to the first direction, Equipped with, The cam follower alternately contacts the cam lobes in order to vibrate the rocker shaft. Rocker shaft and A rotary surgical tool equipped with [a specific feature].

48. The rotary surgical tool according to claim 47, wherein while the counterclockwise cam lobe is in contact with the second cam follower, the clockwise cam lobe does not come into contact with the first cam follower, and while the clockwise cam lobe is in contact with the first cam follower, the counterclockwise cam lobe does not come into contact with the second cam follower.

49. The rotary surgical tool according to claim 47 or 48, further comprising the input shaft and the output shaft, each supported for rotation around a drive shaft.

50. The rotary surgical tool according to claim 49, wherein the drive shaft is coaxial with the cam shaft.

51. The rotary surgical tool according to claim 49 or 50, wherein at least a portion of the rocker shaft passes the drive shaft when the rocker shaft vibrates.

52. The rotary surgical tool according to any one of claims 47 to 51, wherein each of the first cam follower and the second cam follower is provided with a bearing that contacts the cam lobe.

53. The rotary surgical tool according to any one of claims 47 to 51, wherein each of the first cam follower and the second cam follower is provided with a needle bearing that contacts the cam lobe.

54. A rotary surgical tool according to any one of claims 47 to 53, further comprising a spur gear that vibrates around the rocker shaft in response to the alternating contact of the cam follower with the cam lobe, and is configured to engage with the output shaft to impart vibrational motion to the output shaft.

55. The rotary surgical tool according to any one of claims 47 to 54, wherein the cam lobe is spaced away from the cam shaft such that no portion of the cam lobe intersects with the cam shaft.

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