Linear electric surgical hammer impact tool

Abstract

To provide an electric surgical impact tool and a method of use thereof.SOLUTION: Disclosed herein are a linear electric surgical hammer impact tool and a method of use thereof. The linear electric surgical hammer impact tool can include a shuttle located inside a cavity of a housing. A wall of the shuttle defines a plurality of grooves extending from a first end of the shuttle to a second end of the shuttle. A piston can be located at least partially within the shuttle and arranged along the longitudinal axis of the housing. The piston includes protrusions, and each of the protrusions can be arranged to travel within each one of the grooves of the shuttle. Motion of the piston in a first direction causes the piston to contact the first end of the shuttle, and motion of the piston in a second direction causes the piston to contact the second end of the shuttle.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 390,354, filed July 19, 2022, and also claims the benefit of U.S. Provisional Patent Application No. 63 / 450,316, filed March 6, 2023, the priority benefit of each of which is claimed herein, and each of which is incorporated by reference in its entirety.

[0002] The present disclosure relates generally to surgical instruments and methods of use. More specifically, the present disclosure relates to electrosurgical impact tools and methods of use. [Background technology]

[0003] Orthopaedic surgeons typically utilize tools to cut or carve bone that require a hammer or mallet to transmit the implantation force to the tool. One example is the broach tool used to prepare the proximal end of the femur to receive the shaft of a hip implant. The broach may be used with a hammer that the surgeon swings or with a pneumatic "jack hammer"-like tool. However, striking the broach tool with a hammer can be cumbersome and can result in high stress on the surgeon's own joints, such as the shoulder joint. Additionally, pneumatic impact tools require connection to an air hose, which can be inconvenient and may limit the surgeon's ability to orient the tool as desired. Summary of the Invention [Problem to be solved by the invention]

[0004] The following non-limiting examples detail particular aspects of the present subject matter to, among other things, solve the problems and provide the advantages described herein. [Means for solving the problem]

[0005] Example 1 is a linear electrosurgical hammer impact tool comprising: a housing defining a cavity extending along a longitudinal axis of the housing; a shuttle located inside the cavity and disposed along the longitudinal axis of the housing, the shuttle having a first end, a second end, and a wall extending from the first end to the second end, the wall defining a plurality of grooves extending from the first end of the shuttle to the second end of the shuttle; a piston disposed at least partially within the shuttle and disposed along the longitudinal axis of the housing, the piston having a plurality of protrusions, each of the plurality of protrusions arranged to move within a respective one of the plurality of grooves of the shuttle; a motor configured to drive the piston along the longitudinal axis in a first direction and a second direction; and a tool holder connected to the shuttle, wherein movement of the piston in the first direction causes the piston to contact the first end of the shuttle and movement of the piston in the second direction causes the piston to contact the second end of the shuttle.

[0006] In Example 2, the subject matter of Example 1 optionally includes a cap connected to a proximal end of the housing, and a first bias member disposed between the first end of the shuttle and the cap.

[0007] In Example 3, the subject matter of any one or more of Examples 1 to 2 optionally includes a partition disposed within the housing and a second bias member disposed between the second end of the shuttle and the partition.

[0008] In Example 4, the subject matter of any one or more of Examples 2-3 optionally includes at least one of the first bias member and the second bias member comprising a spring.

[0009] In Example 5, the subject matter of any one or more of Examples 1 to 4 optionally includes, each of the plurality of protrusions includes a polymer.

[0010] In Example 6, the subject matter of Example 5 optionally includes impregnating the polymer with a lubricant.

[0011] In Example 7, the subject matter of any one or more of Examples 1 to 6 optionally includes the plurality of protrusions being straight.

[0012] In example 8, the subject matter of any one or more of examples 1-7 optionally includes a sensor positioned to detect a position of the shuttle within the cavity.

[0013] In Example 9, the subject matter of any one or more of Examples 1-8 optionally includes, wherein the tool holder comprises a quick connect / disconnect chuck.

[0014] In example 10, the subject matter of any one or more of examples 1-9 optionally includes a handle defining a cavity sized to receive the electronics and the trigger.

[0015] In Example 11, the subject matter of any one or more of Examples 1-10 optionally includes the tool holder being threadably connected to the shuttle.

[0016] In Example 12, the subject matter of any one or more of Examples 1-11 optionally includes where a distal surface of the tool holder forms the impact surface.

[0017] Example 13 is a linear electrosurgical hammer impact tool comprising: a housing defining a cavity extending along a longitudinal axis of the housing; a shuttle located inside the cavity and disposed along the longitudinal axis of the housing, the shuttle having a first end, a second end, and a wall extending from the first end to the second end, the wall defining a plurality of grooves extending from the first end of the shuttle to the second end of the shuttle; and a piston disposed at least partially within the shuttle and disposed along the longitudinal axis of the housing, the piston having a plurality of protrusions and a flange. a piston arranged to move within a respective one of a plurality of grooves in the shuttle; a motor configured to drive the piston along a longitudinal axis in a first direction and a second direction; and a tool holder threadably connected to the shuttle, the tool holder having a distal surface forming an impact surface, wherein movement of the piston in the first direction causes the piston to contact the impact surface of the tool holder and movement of the piston in the second direction causes a flange of the piston to contact a second end of the shuttle.

[0018] In Example 14, the subject matter of Example 13 optionally includes a cap connected to a proximal end of the housing, and a first bias member disposed between the first end of the shuttle and the cap.

[0019] In Example 15, the subject matter of any one or more of Examples 13 to 14 optionally includes a partition disposed within the housing and a second bias member disposed between the second end of the shuttle and the partition.

[0020] In Example 16, the subject matter of any one or more of Examples 13-15 optionally includes at least one of the first bias member and the second bias member comprising a spring.

[0021] In Example 17, the subject matter of any one or more of Examples 13 to 16 optionally includes, wherein each of the plurality of protrusions comprises a polymer impregnated with a lubricant.

[0022] In Example 18, the subject matter of any one or more of Examples 13 to 17 optionally includes the plurality of protrusions being straight.

[0023] In Example 19, the subject matter of any one or more of Examples 13 to 18 optionally includes a sensor positioned to detect a position of the shuttle within the cavity.

[0024] In Example 20, the subject matter of any one or more of Examples 13 to 19 optionally includes wherein the tool holder comprises a quick connect / disconnect chuck.

[0025] In Example 21, the subject matter of any one or more of Examples 13 to 20 optionally includes a handle defining a cavity sized to receive the electronics and the trigger.

[0026] In Example 21, the surgical impact tools, systems, and / or methods of any one or any combination of Examples 1 to 20 may optionally be configured such that all listed elements or options are available and can be used or selected.

[0027] Example 22 is a linear electrosurgical hammer impact tool comprising: a housing defining a cavity extending along a longitudinal axis of the housing; a shuttle disposed inside the cavity and along the longitudinal axis of the housing, the shuttle having a first end, a second end, and a wall extending from the first end to the second end, the wall including opposing exterior keyways extending a length of an exterior portion of the wall; a hammer assembly disposed at least partially within a proximal end of the shuttle and along the longitudinal axis of the housing; a linear electric motor configured to drive a piston along the longitudinal axis in a first direction and a second direction; and an impact assembly disposed at least partially within a distal end of the shuttle. The linear electric impact tool operates by moving the hammer assembly in a first direction causing the hammer assembly to contact a first end of the shuttle creating a forward impact, and moving the hammer assembly in a second direction causing the hammer assembly to contact a second end of the shuttle creating a reverse impact.

[0028] In Example 23, the subject matter of Example 22 may optionally include a hammer assembly having an impact piston surrounding the impact hammer.

[0029] In Example 24, the subject matter of any one of Examples 22 or 23 may optionally include an impact hammer having a curved proximal contact surface.

[0030] In Example 25, the subject matter of any one of Examples 22 to 24 may optionally include a curved proximal contact surface having a radius of 100 mm.

[0031] In Example 26, the subject matter of any one of Examples 22 to 25 may optionally include an impact piston having a distal circumferential ridge for engaging with the reverse impact cap to generate a backup impact.

[0032] In Example 27, the subject matter of any one of Examples 22 to 26 may optionally include an impact assembly having an impact button adapted to receive an impact from an impact hammer.

[0033] In Example 28, the subject matter of Example 27 may optionally include an impact assembly having an impact interface adapted to transmit an impact received at the impact button to an impact tool, the impact tool being held in a chuck adjacent a distal end of the impact tool.

[0034] In Example 29, the subject matter of any one of Example 27 or Example 28 can optionally include, wherein the impact button is a polymer material and the impact hammer is a high density metal.

[0035] In Example 30, the subject matter of any one of Examples 27 to 29 may optionally include an impact button having a pocket formed to receive a rounded proximal surface of the impact hammer.

[0036] In Example 31, the subject matter of any one of Examples 22 to 30 may optionally include a proximal bias spring and a distal bias spring that act to center the shuttle within the housing and absorb excess impact energy.

[0037] In Example 32, the subject matter of any one of Examples 22 to 32 may optionally include a proximal energy absorption assembly and a distal energy absorption assembly.

[0038] In Example 33, the subject matter of Example 32 can optionally include a proximal energy absorbing assembly having a forward absorbing ring and a proximal biasing ring.

[0039] In Example 34, the subject matter of Example 33 may optionally include a forward absorbing ring that is an energy absorbing rubber and a proximal bias ring that is a metal ring structure configured to receive a proximal bias spring.

[0040] In Example 35, the subject matter of any one of Examples 22 to 34 may optionally include an impact shaft transmitting impact from the impact assembly and extending distally through the impact shaft bearing assembly, the impact shaft bearing assembly acting as a self-aligning shaft bearing on the impact shaft.

[0041] In Example 36, the subject matter of any one of Examples 22 to 35 may optionally include a position sensor assembly including a slider clip for removably connecting the position slider to the shuttle.

[0042] Example 37 is a method of homing of any one of the impact tools of Examples 1 to 36. The homing method can include actuating the linear electric motor to retract the shuttle mechanism to a distal hard stop, monitoring a position sensor assembly during actuation of the linear electric motor, determining that a distal home position has been reached based on feedback from the position sensor assembly and the linear electric motor, and upon determining that the distal home position has been reached, actuating the linear electric motor to move the shuttle mechanism to a proximal home position, and determining that the proximal home position has been reached based on feedback from the position sensor and the linear electric motor.

[0043] In Example 38, the subject matter of Example 37 may optionally include determining that the distal home position has been reached by monitoring voltages at the distal position sensor and the proximal position sensor.

[0044] In Example 39, the subject matter of any one of Examples 37 and 38 may optionally include calibrating the sensor assembly based on voltage readings at the distal home position and the proximal home position.

[0045] Example 40 is a method of actuating any one of the impact tools of examples 1 to 36. The method may include detecting an activation of a trigger mechanism to initiate an impact from the impact tool, determining a position of a shuttle assembly within a housing of the impact tool, the shuttle including a component adapted to generate an impact, determining an intended impact direction from the position of the shuttle assembly, and applying the impact in the intended impact direction by actuating a linear electric impact mechanism.

[0046] In Example 41, the subject matter of Example 40 may optionally include, after applying the impact, determining whether to apply the impact repeatedly based on a position of the trigger mechanism.

[0047] In Example 42, the subject matter of Example 41 can optionally include stopping the linear electric impact mechanism upon determining not to repeatedly apply the impact. [Brief description of the drawings]

[0048] In the drawings, which are not necessarily drawn to scale, like numbers may represent like components in different figures. Like numbers with different letter suffixes may represent different instances of the like components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0049] [Figure 1A] FIG. 1A illustrates a cross-sectional view of a linear electrosurgical hammer impact tool consistent with at least one example of the present disclosure. [Figure 1B]FIG. 1B illustrates a cross-sectional view of a linear electrosurgical hammer impact tool consistent with at least one example of the present disclosure. [Diagram 2] FIG. 2 illustrates a cross-sectional view of a linear electrosurgical hammer impact tool consistent with at least one example of the present disclosure. [Diagram 3] FIG. 3 is a cutaway view of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 4A] FIG. 4A is a perspective view illustrating multiple subassemblies of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 4B] FIG. 4B is a cross-sectional view of multiple subassemblies of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 5A] FIG. 5A is a cross-sectional view of multiple subassemblies of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 5B] FIG. 5B is a cross-sectional view of an impactor subassembly of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 6A] 6A-6D illustrate various views of a shuttle subassembly of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 6B] 6A and 6B are various views of a shuttle subassembly of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 6C] 6A-6C are various views of a shuttle subassembly of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 6D] FIG. 6D is a cross-sectional view of a shuttle subassembly of a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 7] FIG. 7 is a cross-sectional view of a self-aligning impact shaft bearing configuration for a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 8A]8A-8D are various views of a position sensor subassembly for a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 8B] 8A and 8B are various views of a position sensor subassembly for a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 9A] FIG. 9A is a cross-sectional view illustrating various impactor positions within a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 9B] 9A and 9B are cross-sectional views illustrating various impactor positions within a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 9C] 9A-9C are cross-sectional views illustrating various impactor positions within a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 10] FIG. 10 is a flowchart illustrating a homing and calibration technique for a linear electric impact tool consistent with at least one example of the present disclosure. [Figure 11] FIG. 11 is a flow chart illustrating a surgeon's intent detection technique consistent with at least one example of this disclosure.

[0050] Corresponding reference characters indicate corresponding parts throughout the several views. The illustrations described herein illustrate preferred embodiments of the present disclosure, and the illustrations should not be construed as limiting the scope of the present disclosure in any manner. The reference characters used in Figures 3 through 9C do not necessarily bear any correspondence with the reference characters used in previous figures. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] As an alternative to pneumatic piston driven systems, electrically driven systems are disclosed herein. In particular, the linear electrosurgical hammer impact tool disclosed herein can include an impact element, sometimes referred to as a slider, that can impact a shuttle, tool holding element, or the like to generate an impact force.

[0052] The electric motor can be configured to drive the impact element to generate an impact force. For example, movement of the piston in a first direction can cause the piston to contact a first end of the housing, and movement of the piston in a second direction can cause the piston to contact a second end of the housing. Contact between the piston and the housing can generate an impact force to drive the file and / or broach into and withdraw the file and / or broach from the bone canal.

[0053] The above description is intended to provide an overview of the subject matter of this patent application. The above description is not intended to provide an exclusive or exhaustive description of the invention. The following description is included to provide further information regarding this patent application.

[0054] 1A and 1B each show an example of a linear electrosurgical hammer impact tool 100 consistent with at least one example of the present disclosure. As disclosed herein, the linear electrosurgical hammer impact tool 100 may provide a simple, efficient, and rugged battery-powered, handheld linear electrosurgical hammer impact tool for use in surgical procedures. The linear electrosurgical hammer impact tool 100 may include a distal end cap 102 and a proximal end cap 104 at an opposite end of a housing 106. The housing 106 may also be referred to as a tool body and may define a cavity 108.

[0055] The shuttle 110 may be disposed within the cavity 108 and aligned along a longitudinal axis 112 of the housing 106. A tool holder 114 may be connected to the shuttle 110. For example, as shown in FIGS. 1A and 1B, the shuttle 110 may include a first thread 116 and the shuttle 110 may have a second thread 118 that allows the tool holder 114 to be threadably connected to the shuttle 110. Other forms of attachment of the tool holder 114 to the shuttle 110 may include adhesives, a press fit, welding, screws, etc.

[0056] Tools, such as files, broaches, etc., may be mounted to the tool holder 114. For example, a broach may be secured to the tool holder 114 via a pin, screw, or the like. Consistent with embodiments disclosed herein, a chuck 120 may be mounted to the tool holder 114. The chuck 120 may be a quick connect / disconnect chuck that allows a surgeon or other operating room staff to quickly connect and disconnect tools from the linear electrosurgical hammer impact tool 100. For example, the chuck 120 may allow a surgeon to quickly disconnect a first file from the linear electrosurgical hammer impact tool 100 and quickly connect a second file, which may be a different size and / or shape than the first file, to the linear electrosurgical hammer impact tool 100.

[0057] The chuck 120 may be attached to the tool holder 114 via bolts 121. For example, the chuck 120 may define a through hole 123. The bolts 121 may pass through the through hole 123 to secure the chuck 120 to the tool holder 114. The use of the bolts 121 may allow a surgeon or other staff to change the chuck according to the surgeon's preferences. For example, a first surgeon may prefer a first type of chuck and a second surgeon may prefer a second type of chuck. The use of the bolts 121 may allow staff to change the chuck between procedures performed by the first and second surgeons.

[0058] The linear electrosurgical hammer impact tool 100 may further include a piston 122 disposed at least partially within the housing 106. In operation, the piston 122 may move in a first direction as indicated by arrow 124 (FIG. 1A). Movement in the first direction may bring a face 126 of the piston 122 into contact with a face 128 of the shuttle 110 to generate an impact force and drive the tool into bone. The face 128 of the shuttle 110 may be a face of the tool holder 114, sometimes referred to as an impact face.

[0059] Movement of piston 122 in a second direction, as indicated by arrow 125 (FIG. 1B), may cause a distal portion 132 of shuttle 110 to impact against a flange 130 of piston 122. The impact of flange 130 with distal portion 132 may generate a pull-out force that may enable a tool, such as a broach, file, or the like, to be removed from bone.

[0060] The piston 122 may be constructed of a high density material to increase the impact force generated. For example, the piston 122 may be constructed of a metal, such as tungsten, that contains more mass for a given volume of material. As a result, for a given velocity, the piston 122 may have more kinetic energy that may be transferred to the tool holder 114 and / or shuttle 110 via the piston 122 impacting the tool holder 114 and / or shuttle 110 as disclosed herein.

[0061] Shuttle 110 may include a wall 134. Wall 134 may define grooves 136 (labeled individually as grooves 136A and 136B). Piston 122 may include one or more protrusions 138 that fit into each of grooves 136. Protrusions 138 may act as bearings to secure piston 122 in a particular orientation and may additionally provide clearance between wall 134 and piston 122 to minimize friction.

[0062] The protrusions 138 may be constructed of a polymer. The polymeric protrusions may be impregnated with a lubricant to further reduce friction and wear. The protrusions 138 may be secured to the piston 122 via threads, adhesives, a press fit, or the like. A threaded interface between the tool holder 114 and the shuttle 110 may allow the piston 122 to be positioned within the shuttle 110. Once within the shuttle 110, the protrusions 138 may be attached to the piston 122 through the grooves 136, thereby securing the piston 122 in a desired orientation.

[0063] The piston 122 may comprise two components. For example, the piston 122 may include a body portion 138 and a weight 140. Both the body portion 138 and the weight 140 may be made of a metal, a polymer, a ceramic, or a combination thereof. For example, the weight 140 may be made of a high density material such as tungsten, and the body portion 138 may be made of a polymer. The weight 140 may be press fit into the body portion 138. The weight 140 may include threads 142 that may be used to secure the piston to a moveable portion, such as a magnet 144 of a motor 146.

[0064] Motor 146 may be a linear electric motor and may include magnet 144 and a stator 148. Electronics 150 may electrically connect motor 146 to a trigger 152. As disclosed herein, in operation, a user may press trigger 152 to generate an impact force in linear electrosurgical hammer impact tool 100 to drive the tool into bone and / or retract the tool from bone.

[0065] The sensor 154 can be used to determine the position of the piston 122 within the shuttle 110. For example, the sensor 154 can be a Hall effect sensor that can determine the magnetic flux generated by the magnet 144. Based on the magnetic flux or changes in the magnetic flux, the position of the piston 122 can be determined. Based on the position of the piston 122, the electronics 150 can apply a current to the stator 148 to drive the piston 122 and generate the embedding and retracting forces. For example, the motor 146 can be a tubular electromagnetic linear motor having a coil structure, e.g., the stator 148, fixed inside the housing 106. The coil structure actuates a magnetic or ferromagnetic mechanical impact moving element, e.g., the magnet 144, connected to the piston 122 to cause movement based on the position of the magnet as determined by the sensor 154.

[0066] Housing 106 may include a partition 156. As disclosed herein, shuttle 110 may oscillate in a first direction, as indicated by arrow 124, and in a second direction, as indicated by arrow 125. When piston 122 is not in contact with face 128 or distal portion 132, shuttle 110 may be biased toward a neutral position by biasing elements 158 (individually labeled as biasing elements 158A and 158B). Biasing elements 158 may be springs (tension and / or compression), rubber structures, airbags, or the like.

[0067] In operation, the piston 122 may move in a first direction to strike the surface 128. After striking the surface 128, the biasing element 158B may push the tool holder 114 and shuttle 110 in a second direction to reset the shuttle for additional impacts as the piston 122 repeatedly strikes the surface 128. The shuttle 110 may also be biased in the second direction by a user pressing the linear electrosurgical hammer impact tool 100 against the bone. In this case, the biasing element 158A may act as a shock absorber to mitigate the shuttle from impacting the partition 156 after the piston 122 strikes the surface 128.

[0068] Also, during actuation, piston 122 may move in a second direction to strike distal portion 132. After striking distal portion 132, biasing element 158A may push shuttle 110 in a first direction to reset it for additional impacts as piston 122 repeatedly strikes distal portion 132. Shuttle 110 may also be biased in a first direction by a user pulling linear electrosurgical hammer impact tool 100 away from the bone. In this case, biasing element 158B may act as a shock absorber to mitigate shuttle 110 from impacting cap 104 after piston 122 strikes distal portion 132.

[0069] The wall 134 may also define holes 160 (individually labeled as holes 160A, 160B, 160C, and 160D). Plugs 162 (individually labeled as plugs 162A, 162B, 162C, and 162D) may be inserted into the holes 160. The plugs 162 may be polymer plugs impregnated with a lubricant. Thus, the plugs 162 may provide friction reduction while supporting the shuttle 110. The support of the shuttle 110 may function to keep the projections 138 aligned within the grooves 136 to minimize friction and / or binding that may reduce impact forces.

[0070] 2 illustrates an example of a linear electrosurgical hammer impact tool 200 consistent with at least one example of the present disclosure. As disclosed herein, the linear electrosurgical hammer impact tool 200 may provide a simple, efficient, and robust battery-powered, handheld linear electrosurgical hammer impact tool for use in surgical procedures. The linear electrosurgical hammer impact tool 200 may include a distal end cap and a proximal end cap 202 at an opposite end of a housing 204. The housing 204 may also be referred to as a tool body and may define a cavity 206.

[0071] A shuttle 210 may be disposed within the cavity 206 and aligned along a longitudinal axis 212 of the housing 204. A tool holder 214 may be connected to the shuttle 210. For example, as shown in FIG. 2, the tool holder 214 may be threadedly connected to the shuttle 210 by a threaded connection 208. Other forms of attachment of the tool holder 214 to the shuttle 210 may include adhesives, a press fit, welding, screws, etc.

[0072] Tools such as files, broaches, etc. may be attached to the tool holder 214. For example, broaches may be secured to the tool holder 214 via pins, screws, etc. Consistent with embodiments disclosed herein, a chuck 220 may be attached to the tool holder 214. The chuck 220 may be a quick connect / disconnect chuck that allows a surgeon or other operating room staff to quickly connect and disconnect tools from the linear electrosurgical hammer impact tool 200. For example, the chuck 220 may allow a surgeon to quickly disconnect a first file from the linear electrosurgical hammer impact tool 200 and quickly connect a second file, which may be a different size and / or shape than the first file, to the linear electrosurgical hammer impact tool 200. The chuck 220 may be attached to the tool holder 214 via a bolt or other mechanism, as disclosed herein with respect to the chuck 120.

[0073] The linear electrosurgical hammer impact tool 200 may further include a piston 222 disposed at least partially within the housing 204. During actuation, the piston 222 may move in a first direction as indicated by arrow 224. Movement in the first direction may seat a first end 226 of the piston 222 within a recess 227 defined by the tool holder 214 to generate an impact force and drive the tool into bone.

[0074] Movement of the piston 222 in a second direction, as indicated by arrow 225, may cause a distal portion 232 of the shuttle 210 to impact against a flange 230 of the piston 222. The impact of the flange 230 with the distal portion 232 may generate a pull-out force that may enable a tool, such as a broach, file, or the like, to be removed from bone.

[0075] The piston 222 may be constructed of a high density material to increase the impact force generated. For example, the piston 222 may be constructed of a metal, such as tungsten, that contains more mass for a given volume of material. As a result, for a given velocity, the piston 222 may have more kinetic energy that may be transferred to the tool holder 214 and / or shuttle 210 via the piston 222 impacting the tool holder 214 and / or shuttle 210 as disclosed herein.

[0076] Shuttle 210 may include a wall 234. Wall 234 may define grooves 236 (individually labeled as grooves 236A and 236B). Piston 222 may include one or more protrusions, such as disclosed herein for protrusions 138, that fit into each of grooves 236 to act as bearings to secure piston 222 in a particular orientation, as well as to provide clearance between wall 234 and piston 222 to minimize friction. The protrusions may be comprised of a polymer impregnated with a lubricant and connected to piston 222 as disclosed herein.

[0077] The piston 222 may be connected to the slider element 233 via a connecting member 235. The connecting member 235 may be a threaded rod, a rod press-fit into both the slider element 233 and the piston 222, a rod welded to the slider element 233, and / or a rod via adhesive. The piston 222 may include a weight and may be multiple components as disclosed with respect to the piston 122.

[0078] The slider element 233 may be part of a motor 246, which may be a linear electric motor and may include a magnet 244 and a stator 248. As disclosed herein, electronics may electrically connect the motor 246 to a trigger. As disclosed herein, in operation, a user may press the trigger to generate an impact force in the linear electrosurgical hammer impact tool 200 to drive the tool into and / or retract the tool from the bone.

[0079] The sensor 254 can be used to determine the position of the piston 222 within the shuttle 210. For example, the sensor 254 can be a Hall effect sensor that can determine the magnetic flux generated by the magnet 244. Based on the magnetic flux or changes in the magnetic flux, the position of the piston 222 can be determined. Based on the position of the piston 222, the electronics can apply a current to the stator 248 to drive the piston 222 and generate the embedding and retracting forces. For example, the motor 246 can be a tubular electromagnetic linear motor having a coil structure, e.g., the stator 248, fixed inside the housing 204. The coil structure actuates a magnetic or ferromagnetic mechanical impact moving element, e.g., the magnet 244, connected to the piston 222 to cause movement based on the position of the magnet as determined by the sensor 254.

[0080] The housing 204 may include a partition 256. As disclosed herein, the shuttle 210 may oscillate in a first direction as indicated by arrow 224 and in a second direction as indicated by arrow 225. When the piston 222 is not in contact with the tool holder 214 or the distal portion 232, the shuttle 210 may be biased toward a neutral position by biasing elements 258 (individually labeled as biasing elements 258A and 258B). The biasing elements 258 may be springs (tension and / or compression), rubber structures, air bags, or the like.

[0081] During actuation, the piston 222 may move in a first direction to strike the tool holder 214. After striking the tool holder 214, the biasing element 258B may push the tool holder 214 and shuttle 210 in a second direction to reset the shuttle for additional impacts as the piston 222 repeatedly strikes the tool holder 214. The shuttle 210 may also be biased in the second direction by a user pressing the linear electrosurgical hammer impact tool 200 against the bone. In this case, the biasing element 258A may act as a shock absorber to mitigate the shuttle 210 from impacting the partition 256 after the piston 222 strikes the tool holder 214.

[0082] Also, during actuation, piston 222 may move in a second direction to strike distal portion 232. After striking distal portion 232, biasing element 258A may push shuttle 210 in a first direction to reset it for additional impacts as piston 222 repeatedly strikes distal portion 232. Shuttle 210 may also be biased in a first direction by a user pulling linear electrosurgical hammer impact tool 200 away from the bone. In this case, biasing element 258B may act as a shock absorber to mitigate the shuttle from impacting cap 202 after piston 222 strikes distal portion 232.

[0083] The following describes additional embodiments of an impact instrument designed for use in orthopedic joint replacement procedures, among other surgical procedures. The impact instrument described below is another instrument that utilizes a linear electric motor to drive a hammer assembly in a shuttle structure to generate forward and / or reverse impacts on an attached instrument, such as a broach or file. Similar to the tools described above, the electric motor can be configured to drive an impact element to generate an impact force. The following description focuses on areas where this exemplary impact instrument differs from the devices described above. The basic operating characteristics are similar between the two examples, as both utilize a similar linear electric motor to drive a hammer assembly to generate an impact force on an attached impact instrument, such as a broach or file.

[0084] FIG. 3 is a cutaway view of a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, the impact tool 300 is shown in a partial cutaway view with a portion of the housing 302 removed to allow visualization of certain subassemblies within the tool. The cutaway portion of the housing 302 reveals a shuttle assembly 310 and a linear electric motor assembly 320. The shuttle assembly 310 is a structure that generates an impact force that is transferred to an instrument connected to a chuck 330. The shuttle may include a cylindrical body that includes impact receiving structures at both distal and proximal ends. The shuttle also holds an impact hammer assembly, which is the portion of the impact tool 300 that moves to generate the impact force. The impact hammer assembly is moved linearly by the linear electric motor assembly 320. More details about these subassemblies are discussed below with reference to FIGS. 4A-8B.

[0085] The impact tool 300 also includes a battery assembly 340 and a handle 350. In this example, the handle 350 includes a trigger 352 for actuation of the impact tool 300. The housing 302 also includes a proximal end cap 304 that threads onto the proximal end of the housing 302. Adjacent to the proximal end cap 304 is a proximal cap seal 306 that seals the proximal end of the impact tool 300.

[0086] In this example, the housing 302 of the impact tool 300 is an injection molded plastic or polymer that is laser welded together during the assembly process. Specifically, the housing 302 is designed to minimize impact on the motor dynamics of the linear electric motor assembly 320. The use of injection molded plastic was advantageous over a metal housing such as aluminum to avoid eddy current damping effects on the linear electric motor. Another housing material option that may be used to similarly avoid eddy current impacts is a laminated non-conductive or low conductivity metal forming the housing 302.

[0087] FIG. 4A is a perspective view showing several subassemblies of a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, FIG. 4A shows a shuttle assembly 310 and a linear electric motor assembly 320 removed from the impact tool 300. In this example, the shuttle assembly 310 includes a cylindrical shuttle housing 401 having a plurality of shuttle vents 402 and at least two opposing keyways for receiving a shuttle key 405. The shuttle vents 402 operate to vent the interior of the shuttle housing 401, thereby reducing air compression induced drag in the hammer assembly 430. The shuttle key 405 limits rotation of the shuttle housing 401 relative to the housing 302 of the impact tool 300. The shuttle assembly 310 also includes a distal energy absorption assembly 440, which will be discussed in detail below. The linear electric motor assembly 320 may include a control circuit assembly 322 including a circuit board including control electronics for controlling the linear electric motor and providing position feedback regarding the hammer assembly within the shuttle housing 401. The figure also includes an illustration of a chuck 330 and a chuck lock 332. The chuck lock 332 rotates to lock the impact instrument to the impact tool 300.

[0088] 4B is a cross-sectional view of multiple subassemblies of a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, the subassemblies described above are shown in cross-section to detail additional components within each subassembly. In this example, the linear electric motor assembly 320 can include a linear electric motor, a control circuit assembly 322, and a position sensor assembly 470. The position sensor assembly 470 includes structure that is fastened to the shuttle housing 401 to monitor the position of the shuttle assembly 310 during operation. The linear electric motor (described in detail above) includes an internal sensor to provide feedback on the position of the hammer assembly 430.

[0089] In this example, the shuttle assembly 310 includes a shuttle housing 401, an impact assembly 410, a hammer assembly 430, a distal energy absorption assembly 440, a proximal energy absorption assembly 450, and an impact shaft bearing assembly 460. The impact assembly 410 may include an impact button 412 and an impact interface 414. The impact button 412 is for receiving a forward impact from an impact hammer 432. To minimize energy loss due to vibration, the impact button 412 may be made of a low-loss polymer material such as Acetal® or Delrin®. Low-loss polymers have low-wear properties that enable the impact assembly 410 to provide a long service life. In this example, the impact hammer 432 is part of a hammer assembly 430 that also includes a reverse impact piston 434. The impact button 412 also includes a pocket formed to receive the rounded proximal surface of the impact hammer 432, which further enhances the energy transfer between the impact hammer 432 and the impact button 412. The radius of the proximal surface allows the edge of the impact zone of the impact hammer 432 to avoid contact with the surface of the impact button 412. The radius of the proximal surface may be within a range of 10% to 25% of the diameter of the impact button 412 to achieve the goal of avoiding edge contact. In this example, the impact button 412 is held in a recess within the impact interface 414. The impact interface 414 transfers the energy received by the impact button 412 to the impact tool held in the chuck 330. The impact interface 414 includes a proximal shaft extending outside the shuttle housing 401 that operatively connects to a distal end of an impact shaft extending distally from the chuck 330. The impact shaft is held in place by an impact shaft bearing assembly 460.

[0090] In this example, the impact hammer 432 is a high density metallic material to improve impact energy transfer to the impact button 412. The combination of the high density metallic impact hammer 432 and the stiff polymeric impact button 412 operates like a dead blow hammer to efficiently transfer impact force to the impact equipment connected to the chuck 330. Another component of the hammer assembly 430 is a reverse impact piston 434, which may also be a high density metallic material and is designed to provide a reverse (or distal) impact against a reverse impact cap 416 that is threaded into the distal end of the shuttle housing 401. Similar to the impact button 412, the reverse impact cap 416 may be made of a stiff polymeric material to efficiently transfer reverse impact force to the shuttle housing 401. In a particular example, the reverse impact cap 416 may be made of a metallic material to improve wear characteristics, while the system relies on a long force path generated by the shuttle housing 401 to damp any vibrations generated during the reverse impact.

[0091] In this example, the shuttle assembly 310 also includes a proximal bias spring 408 and a distal bias spring 409 (collectively referred to herein as the "bias springs"). The bias springs operate to keep the shuttle housing 401 centered within the housing 302 during actuation. The bias springs also operate to dissipate excess impact energy that is not transferred to the impact device. In the example, energy dissipation is enhanced by a proximal energy absorption assembly 450 and a distal energy absorption assembly 440 (collectively referred to herein as the "energy absorption assemblies"). The energy absorption assemblies include additional energy absorbing components to dissipate impact forces in the event of a dry strike or in situations where the impact device is not fully engaged or otherwise unable to fully absorb the impact energy generated by the tool. The energy absorption assemblies operate to minimize the transmission of undesired forces to the housing 302 and ultimately to the user of the impact tool 300. In this example, the distal energy absorption assembly 440 includes a reverse absorption ring 442 and a distal bias ring 444. The reverse absorption ring 442 may be made of an energy absorbing rubber, such as Sorbothane®. The distal bias ring 444 may be a metal ring that receives a bias force from the distal bias spring 409. The proximal energy absorption assembly 450 may include a forward absorption ring 452 and a proximal bias ring 454. Similar to the reverse absorption ring 442, the proximal absorption ring 452 may be made of an energy absorbing rubber compound, such as Sorbothane®. The proximal bias ring 454 is a metal ring structure designed to receive the proximal bias spring 408 and protect the proximal absorption ring 452. Distal bias ring 444 and proximal bias ring 454 also act to distribute the force from the bias spring when the bias spring is compressed by a forward or reverse impact.

[0092] The impact shaft bearing assembly 460 acts as a self-aligning shaft bearing on the impact shaft that transmits the impact from the shaft assembly 310 to the chuck 330. In an example, the impact shaft bearing assembly 460 may include a shaft bearing 462, a bearing housing 464, a housing O-ring 466, a shaft seal 468, and a snap ring 469. The shaft bearing 462 guides the impact shaft and allows linear lateral motion of the impact shaft. The bearing housing 464 and the housing O-ring 466 cooperate to create a self-aligning bearing assembly by allowing small angular motion of the impact shaft within the impact shaft bearing assembly 460. The shaft seal 468 ensures that foreign matter does not enter the impact tool 300 via the impact shaft. And, the snap ring 469 retains the impact shaft bearing assembly 460 in the proximal end cap 304.

[0093] 5A is a cross-sectional view of several subassemblies of a linear electric impact tool 300 consistent with at least one example of the present disclosure. This view removes additional housing components of the impact tool 300 to provide additional detail of the shuttle assembly 310 and the linear electric motor assembly 320 (note that only the linear electric motor is shown in this view). The example shown includes, as part of the shuttle assembly 310, an impact assembly 410, a hammer assembly 430, a distal energy absorption assembly 440, a proximal energy absorption assembly 450, and an impact shaft bearing assembly 460. Each component of the illustrated assemblies is described above. FIG. 5A also includes a position slider 472 and a position magnet 474, which are components of a position sensor assembly 470.

[0094] 5B is a cross-sectional view of an impactor subassembly of a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, the impactor subassembly corresponds to the shuttle assembly 310 described above with reference to FIGS. 4A-5A. In this example, only the shuttle assembly 310 is shown with a chuck 330 connected to an impact shaft extending from an impact interface 414. FIG. 5B allows visualization of additional details, such as the curvature at the proximal face of the impact hammer 432. In the example, the proximal face of the impact hammer 432 includes a radius of 100 mm. The impact hammer 432 may be milled or cast from a metallic material, such as stainless steel or tungsten.

[0095] 6A-6C are various views of a shuttle subassembly 310 of a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, the shuttle assembly 310 is shown removed from the remainder of the impact tool 300. The shuttle assembly 310 may include a shuttle housing 401, a number of shuttle vents 402, and opposing keyways 406 for receiving a shuttle key 405. The figures also include components such as a distal energy absorbing assembly 440 and a distal bias spring 409. The threaded end of the impact hammer 432 is shown extending distally from the reverse impact piston 434. In the example, a linear electric motor is threaded into the impact hammer 432. At the proximal end of the shuttle housing 401, the proximal end of the impact interface 414 is shown. The proximal end of the impact interface 414 receives an impact shaft connected to the chuck 330.

[0096] 6B and 6C include views of the parts of the position sensor assembly 470, such as the position slider 472, the position magnet 474, and the slider clip 476. The slider clip 476 is the component that connects the position sensor assembly 470 to the shuttle housing 401. More specifically, the slider clip 476 is connected to the upper end of the position slider 472, which includes a tapered cross section to be accommodated in the slider clip 476. The slider clip 476 allows the shuttle assembly 310 and the linear electric motor assembly 320 parts to be easily inserted into the tool housing 302 after the electronics and battery are assembled into the housing 302. The slider clip 476 is designed to require low engagement forces due to the angled arms and high separation forces due to the steep extension in the arms. Thus, the shuttle and motor assemblies can be easily inserted while also allowing (albeit difficult) to be removed. The slider clip 476 is designed to release the shuttle assembly 310 when sufficient force is applied, allowing maintenance or repair of these critical components.

[0097] 6D is a cross-sectional view of a shuttle subassembly 310 of a linear electric impact tool 300 consistent with at least one example of the present disclosure. This view is included to provide additional perspective on the orientation of the various components shown. Details of each of the components shown are included above.

[0098] FIG. 7 is a cross-sectional view of a self-aligning impact shaft bearing configuration for a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, an impact shaft bearing assembly 460 is shown positioned within the proximal end cap 304 of the housing 302. A proximal energy absorbing assembly 450 including a forward absorbing ring 452 and a proximal biasing ring 454 is also included in this view. The proximal energy absorbing assembly 450 is positioned within a deep cylindrical groove on the distal side of the proximal end cap 304. The proximal end cap 304 also includes a central cylindrical bore with a snap ring groove to hold the impact shaft bearing assembly 460. As described above, the impact shaft bearing assembly includes a shaft bearing 462, a bearing housing 464, a housing O-ring 466, and a shaft seal 468. In this example, the housing O-ring 466 is depicted within an O-ring groove on the outer surface of the bearing housing 464. The housing O-ring 466 is biased toward the proximal end of the bearing housing 464 in this example. In another example, the housing O-ring 466 may be located in a centrally located O-ring groove between the proximal and distal ends of the bearing housing 464. A centrally located O-ring groove provides different angular self-centering characteristics. Similarly, the O-ring groove may be located near the distal end of the bearing housing 464, but in this location, angular self-centering may be limited by the proximity of the snap ring that retains the impact shaft bearing assembly 460.

[0099] 8A-8B are various views of a position sensor subassembly 470 for a linear electric impact tool 300 consistent with at least one example of the present disclosure. In this example, the position sensor assembly 470 includes a position slider 472, a position magnet 474, a track 475, a slider clip 476, and position sensors 478A, 478B (collectively referred to as position sensor 478). The position slider 472 is clipped to the slider clip 476 for connecting the position slider 472 to the shuttle housing 401. The purpose of the position sensor assembly 470 is to provide position tracking information for the shuttle assembly 310, and more specifically, the shuttle housing 401. The position of the shuttle housing 401 is used for a number of control functions, including prediction of user intent (characteristic of the surgeon's intent). The impact tool 300 includes a control circuit for predicting the user intent for a forward or reverse impact, including the position sensor assembly 470. Surgeon intent is described in more detail below with reference to the flow chart of FIG.

[0100] The position sensor assembly 470 includes two position sensors 478 to cover the required travel distance and provide both position and direction of motion. The sensor configuration also allows for on-the-fly calibration and tool function verification at start-up (described in more detail below with reference to FIG. 10). In an example, the position sensor 478 is a Hall effect sensor. The principle of the "Hall effect" involves a current carrying conductor or semiconductor being introduced into a perpendicular magnetic field and a voltage can be measured at right angles to the current path. In this system, the position magnet 474 generates a magnetic field which is then sensed by the position sensor 478 which generates a voltage in the range of 0 to 3.3 volts. The control circuit assembly 322 includes processing instructions and / or circuitry that combines the output from the two sensors to determine the position of the shuttle housing 401. The processing instructions and / or circuitry may also determine the direction of motion from the sensor output. Sensor output processing is described in more detail below with reference to FIGS. 12A and 12B.

[0101] 9A-9C are cross-sectional views of parts of the shuttle assembly 310 and linear electric motor assembly 320 illustrating various hammer assembly 430 positions during operation of the impact tool 300. FIG. 9A illustrates the reverse impact position for the hammer assembly 430. In this position, the hammer assembly 430 is at its most distal position within the impact tool 300. The shuttle housing 401 is compressing the distal bias spring 409 and providing a reverse impact to any impact device attached to the chuck 330. FIG. 9B illustrates the hammer assembly 430 and shuttle housing 401 in a forward impact position. In the forward impact position, the hammer assembly 430 is impacting the impact button 412 and transmitting an impact force to the impact device attached to the chuck 330. The proximal bias spring 408 is fully compressed in this position. FIG. 9C illustrates the impact assembly 430 and shuttle housing 401 in a neutral position. In the neutral position, both bias springs are operating to center the shuttle housing 401. As shown in FIG. 9C, with the hammer assembly 430 parked in the neutral position, the shuttle housing 401 can be biased distally or proximally by the user pushing down or pulling back on the impact device attached to the impact tool 300. The bias of the shuttle housing 401 and the resulting change in the signal from the position sensor assembly are utilized by the control circuit to predict the user's intent (e.g., to predict whether a forward or reverse impact is desired when the trigger is pulled). If a forward impact is intended, the user pushes down on the impact device, which biases the shuttle housing 401 distally. Conversely, if a reverse impact is intended, the user pulls back on the impact tool, which biases the shuttle housing 401 proximally. Of course, this assumes that there is some resistance to pulling out the impact device resulting in the bias of the shuttle housing 401. The surgeon (user) intent approach is further described below with reference to FIG.

[0102] 10 is a flow chart illustrating a homing and calibration method 1000 for a linear electric impact tool consistent with at least one example of the present disclosure. In this example, the method 1000 may include operations such as initiating a homing sequence at 1002, retracting to a hard stop at 1004, monitoring a sensor at 1006, determining if in a distal home position at 1008, moving to a forward home position at 1010, monitoring a sensor at 1012, determining if in a proximal home position at 1014, and optionally calibrating the sensor at 1016.

[0103] At 1002, the method 1000 may begin by powering up the impact tool 300 to begin a home sequence. The home sequence may be initiated at other times, such as if the control circuit detects a malfunction or through manual initiation as needed. At 1004, the method 1000 continues with the linear electric motor assembly 320 moving the hammer assembly 430 in the reverse direction to reach a hard stop. During operation from reserve to hard stop, the method 1000 continues with the control circuit monitoring sensor outputs at 1006. The control circuit monitors the sensor outputs from the linear electric motor assembly 320 and the position sensor assembly 470. One of the outputs monitored is the motor torque, and the control circuit monitors for a spike in the motor torque that should indicate that the reverse hard stop has been reached. If the motor torque spike is above a predefined threshold, the position sensor is read to see if the hammer assembly 430 has reached the expected reverse hard stop position. At the expected full reverse position, the distal position sensor 478A will be at or near a peak voltage of 3.3 volts and the proximal position sensor 478B will be below a predefined threshold, such as less than 2.5 volts or less than 1.25 volts. The thresholds used in these algorithms may be adjusted during calibration. At 1008, the method 1000 continues as the control circuit determines whether the motor torque and sensor output readings indicate that the motor and hammer assembly 430 has reached a reverse hard stop position (e.g., distal home), and if so, the method 1000 continues to operation 1010. If not, the method 1000 loops back to operation 1006 where the control circuit continues to monitor the sensors.

[0104] At 1010, method 1000 continues with the linear electric motor assembly 320 slowly moving the hammer assembly 430 forward toward a proximal home position (where the proximal end of the tool includes an impact device). At 1012, method 1000 continues with the control circuit monitoring sensor outputs as the motor moves the hammer assembly 430 to the proximal home position. The sensor outputs monitored at 1012 may include motor torque, distance traveled, and the position sensors 478 (particularly the proximal position sensor 478B). At 1014, method 1000 continues with the control circuit determining whether the proximal home position has been reached. An indication that the hammer assembly 430 has reached the proximal home position may include the distance traveled (as measured by the linear electric motor assembly 320), detection of a motor torque peak, and detection of a peak in the proximal position sensor 478B. If the predefined parameters are met, method 1000 continues and may optionally calibrate the position sensor at 1016. If the parameters are not met, method 1000 loops back to operation 1012 where the control circuit continues to monitor the sensor output. At 1016, the control circuit may calibrate the output of position sensor 478 using the position sensor output at the distal and proximal home positions and method 1000 may end. During the various homing operations, the control circuit may collect the range of the output (maximum and minimum voltage) from each sensor. From the minimum and maximum voltage values, the control circuit captures the offset and range of each sensor, which allows the control circuit to calibrate the offset and gain for each sensor based on this data.

[0105] 11 is a flow chart illustrating a surgeon's intent detection technique 1100 consistent with at least one example of the present disclosure. The surgeon's (e.g., user's) intent detection technique describes how the impact tool 300 determines in which direction to generate an impact force (e.g., forward impact vs. reverse impact) in response to a surgeon's input. The technique is implemented within a control circuit that is part of the linear electric motor assembly 320, and more specifically, part of the control circuit assembly 322. In this example, the technique 1100 may include operations such as detecting a trigger pull at 1102, determining a shuttle housing position at 1104, determining an impact direction at 1106, initiating a forward impact at 1108 or a reverse impact at 1110, determining whether to repeat the impact at 1112, and parking the impact hammer at 1114.

[0106] In this example, method 1100 begins at 1102 with the control circuit detecting that a trigger pull has occurred. Method 1100 continues at 1104 with the control circuit querying the position sensor assembly 470 to determine the position of the shuttle housing 401 within the impact tool 300. Method 1100 continues at 1106 with the control circuit determining the intended impact direction based on the position of the shuttle housing 401. If the position sensor assembly 470 indicates that the shuttle is being pushed distally into the impact tool, a forward impact is intended. If the position sensor assembly 470 indicates that the shuttle is being pulled proximally, a reverse impact is intended. If the shuttle housing 401 is in a neutral position, the control circuit initiates an impact in the same direction as the previous impact.

[0107] As part of operation 1106, method 1100 includes a control circuit receiving position information from both position sensors 478. A first option for determining the intended direction of impact involves a logic flip-flop function. With a logic flip-flop, the output from each of the position sensors is fed through a relay function that includes predefined threshold voltage values ​​that result in an on or off signal (e.g., a binary signal) from each of the position sensors. The binary signal is then fed to the flip-flop circuit such that if the distal position sensor 478A is on and the proximal position sensor 478B is off, the intended direction is set to a forward direction, and if the distal position sensor 478A is off and the proximal position sensor 478B is on, the intended direction is set to a reverse direction.

[0108] A second option for determining the intended direction of impact involves combining the output of the position sensors and using a relay function to switch between forward and reverse intent. In this option, the control circuit reads the output from each position sensor 478, subtracts an offset from the output value, and feeds the result to the arc extinguishing function. To avoid output jumps, the output of the arc extinguishing function is fed through an unwrap function, which provides a linear output of the shuttle housing 401 position. The unwrap function output is then fed through a relay function with a two-way threshold for switching the intended direction. Starting at the most distal position, as the shuttle housing 401 position moves proximally, the forward intended direction is maintained until processed position data indicates that the proximal threshold has been exceeded, at which time the intended direction is switched to a reverse impact. The control circuit maintains the reverse impact intent until the shuttle housing position indicates that movement back in the distal direction has exceeded the distal threshold. The proximal and distal thresholds are predefined positions that can be programmed into the control circuit.

[0109] If, at 1108, it is determined that the shuttle housing 401 is more distally located within the impact tool 300, the method 1100 continues and initiates a forward impact. In this state, the control circuit triggers a forward impact trajectory that involves moving the hammer assembly 430 distally toward a predefined position and accelerating the hammer assembly 430 proximally to impact the impact button 412. The control circuit determines which intensity setting the tool is at and selects the forward impact trajectory accordingly. At a low setting, the hammer assembly 430 may initiate the forward impact trajectory at a first position that is more proximal than if the tool were set to a higher intensity setting. At the higher intensity setting, the hammer assembly 430 may move closer to the most distal range of motion for the linear electric motor assembly 320.

[0110] If, at 1110, it is determined that the shuttle housing 401 is more proximally located within the impact tool 300, the control circuit may initiate a reverse impact and method 1100 may continue. In this condition, the control circuit may trigger a reverse impact trajectory that involves moving the hammer assembly 430 proximally from a parked position to a predefined start position and accelerating the hammer assembly 430 distally to impact the reverse impact cap 416. In an example, the reverse impacts may all be initiated from the same predefined position proximal to the neutral stop position.

[0111] At 1112, the control circuit determines whether the impact tool 300 is configured for repeated impacts (including whether the trigger remains activated) and the method 1100 continues. If a repeated impact condition is not detected, the control circuit may command the linear electric motor assembly 320 to park the hammer assembly 430 and the method 1100 may end at 1114. If a repeated impact condition is detected, the method 1100 returns to operation 1104 to determine the position of the shuttle housing 401 and evaluate the surgeon's intent for the next impact. By continually monitoring the surgeon's intent in this manner, impact techniques such as sawing may be performed with the impact tool 300.

[0112] Note The above detailed description includes reference to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. Such embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the inventors also contemplate examples using any combination or permutation of the elements shown or described (or one or more aspects thereof) with respect to a particular example (or one or more aspects thereof) or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0113] In the event of a conflict in language between this specification and any specification incorporated by reference, the language in this specification shall control.

[0114] As is common in patent specifications, the terms "a" or "an" are used herein to include one or more than one, independent of any other occurrence or usage of "at least one" or "one or more." The term "or" is used herein to refer to a non-exclusive, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. The terms "including" and "in which" are used herein as the plain English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, i.e., a system, device, article, composition, formulation, or process that includes additional elements to those recited after such term in a claim will still be deemed to be within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0115] The above description is intended to be illustrative, not limiting. For example, the above examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used by those of ordinary skill in the art upon reviewing the above description. The Abstract is provided in compliance with 37 C.FR §1.72(b) to enable the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be construed as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may reside in less than all features of a particular disclosed embodiment. Thus, the following claims are herein incorporated by reference in the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the present invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. According to aspect (1), there is provided a linear electrosurgical hammer impact tool, comprising: a housing defining a cavity extending along a longitudinal axis of the housing; a shuttle located inside the cavity and disposed along the longitudinal axis of the housing, the shuttle having a first end, a second end, and a wall extending from the first end to the second end, the wall including opposed exterior keyways extending the length of an exterior portion of the wall; a hammer assembly disposed at least partially within a proximal end of the shuttle and aligned along the longitudinal axis of the housing; a linear electric motor configured to drive a piston in a first direction and a second direction along the longitudinal axis; an impact assembly disposed at least partially within a distal end of the shuttle; Equipped with A linear electrosurgical hammer impact tool, wherein movement of the hammer assembly in the first direction causes the hammer assembly to contact the first end of the shuttle creating a forward impact, and movement of the hammer assembly in the second direction causes the hammer assembly to contact the second end of the shuttle creating a reverse impact. According to aspect (2), the hammer assembly includes an impact piston surrounding the impact hammer. According to aspect (3), the impact hammer includes a curved proximal contact surface. According to aspect (4), the curved proximal contact surface includes a radius of 100 mm. According to aspect (5), the impact piston includes a distal circumferential ridge for engaging a reverse impact cap to generate a pre-impact. According to aspect (6), the impact assembly includes an impact button adapted to receive an impact from the impact hammer. According to aspect (7), the impact assembly includes an impact interface adapted to transmit an impact received at the impact button to an impact tool held in a chuck adjacent a distal end of the impact tool. According to aspect (8), the impact button is made of a polymer material and the impact hammer is made of a high-density metal. According to aspect (9), the impact button includes a pocket configured to receive a rounded proximal surface of the impact hammer. According to aspect (10), the drive shaft further includes a proximal bias spring and a distal bias spring that act to center the shuttle within the housing and absorb excess impact energy. According to aspect (11), the device further includes a proximal energy absorption assembly and a distal energy absorption assembly. According to aspect (12), the proximal energy absorption assembly includes a forward absorption ring and a proximal bias ring. According to aspect (13), the forward absorbing ring is an energy absorbing rubber and the proximal bias ring is a metal ring structure configured to receive a proximal bias spring. According to aspect (14), an impact shaft transmits impact from the impact assembly and extends distally through an impact shaft bearing assembly, which acts as a self-aligning shaft bearing on the impact shaft. According to aspect (15), the position sensor assembly further includes a slider clip for removably connecting a position slider to the shuttle. According to an aspect (16), there is provided a method of homing an impact tool, the method comprising: actuating the linear electric motor to retract the shuttle mechanism to a distal hard stop; monitoring a position sensor assembly during operation of the linear electric motor; determining that a distal home position has been reached based on feedback from the position sensor assembly and the linear electric motor; and upon determining that the distal home position has been reached, actuating the linear electric motor to move the shuttle mechanism to a proximal home position; determining when the proximal home position has been reached based on feedback from the position sensor and the linear electric motor; The method includes: According to aspect (17), determining that the distal home position has been reached includes monitoring voltages at a distal position sensor and a proximal position sensor. According to aspect (18), the method further includes calibrating the sensor assembly based on voltage readings at the distal home position and the proximal home position. According to an aspect (19), there is provided a method of operating an impact tool, the method comprising: detecting activation of a trigger mechanism to initiate an impact from the impact tool; determining a position of a shuttle assembly within a housing of the impact tool, the shuttle including a component adapted to generate an impact; determining an intended impact direction from a position of the shuttle assembly; applying an impact in the intended impact direction by actuating a linear electric impact mechanism; The method includes: According to aspect (20), the method further includes, after applying the impact, determining whether to apply the impact repeatedly based on a position of the trigger mechanism. According to aspect (21), the method further includes stopping the linear electric impact mechanism upon determining not to repeatedly apply the impact.

Claims

1. 1. A linear electrosurgical hammer impact tool comprising: a housing defining a cavity extending along a longitudinal axis of the housing; a shuttle located inside the cavity and disposed along the longitudinal axis of the housing, the shuttle having a proximal end, a distal end, and a wall extending from the proximal end to the distal end, the wall including opposed exterior keyways extending the length of an exterior portion of the wall; a hammer assembly disposed at least partially within a distal end of the shuttle and aligned along the longitudinal axis of the housing, the hammer assembly including a piston; a linear electric motor configured to drive a piston along the longitudinal axis in a first direction from the distal end to the proximal end of the shuttle and in a second direction from the proximal end to the distal end of the shuttle; an impact assembly disposed at least partially within a proximal end of the shuttle; Equipped with a linear electrosurgical hammer impact tool, wherein movement of the piston in the first direction causes the hammer assembly to contact the proximal end of the shuttle to create a forward impact, and movement of the piston in a second direction causes the piston to contact the distal end of the shuttle to create a reverse impact.

2. The impact tool of claim 1 , wherein the hammer assembly includes an impact hammer and the piston of the hammer assembly surrounding the impact hammer.

3. The impact tool of claim 2 , wherein the impact hammer includes a curved proximal contact surface.

4. The impact tool of claim 3 , wherein the curved proximal contact surface includes a radius of 100 mm.

5. The impact tool of claim 2 , wherein the piston includes a distal circumferential ridge for engaging a reverse impact cap to generate a pre-impact.

6. The impact tool of claim 2 , wherein the impact assembly includes an impact button adapted to receive an impact from the impact hammer.

7. 7. The impact tool of claim 6, wherein the impact assembly includes an impact interface adapted to transmit an impact received at the impact button to an impact shaft held in a chuck adjacent a proximal end of the impact tool.

8. 7. The impact tool of claim 6, wherein the impact button is a polymeric material and the impact hammer is a high density metal.

9. The impact tool of claim 6 , wherein the impact button includes a pocket configured to receive a rounded proximal surface of the impact hammer.

10. The impact tool of claim 1 , further comprising proximal and distal bias springs that act to center the shuttle within the housing and absorb excess impact energy.

11. The impact tool of claim 1 , further comprising a proximal energy absorbing assembly for absorbing the forward impact and a distal energy absorbing assembly for absorbing the reverse impact.

12. The impact tool of claim 11 , wherein the proximal energy absorbing assembly includes a forward absorbing ring and a proximal biasing ring.

13. 13. The impact tool of claim 12, wherein the forward absorbing ring is an energy absorbing rubber and the proximal bias ring is a metal ring structure configured to receive a proximal bias spring.

14. the linear electrosurgical hammer impact tool comprises an impact shaft connected to the impact assembly and extending proximally therefrom, and an impact shaft bearing assembly that holds the impact shaft, the impact shaft bearing assembly including a shaft bearing, a bearing housing, a housing O-ring, a shaft seal, and a snap ring; 2. The impact tool of claim 1, wherein the shaft bearing guides the impact shaft and allows linear lateral movement of the impact shaft to act as a self-aligning shaft bearing on the impact shaft as the forward impact from the impact assembly is transmitted to the impact shaft.

15. The impact tool of claim 1 , further comprising a position sensor assembly including a slider clip for removably connecting a position slider to the shuttle.

16. 1. A method of homing an impact tool, the method comprising: actuating the linear electric motor to retract the shuttle mechanism to a distal hard stop; monitoring a position sensor assembly during operation of the linear electric motor; determining that a distal home position has been reached based on feedback from the position sensor assembly and the linear electric motor; and upon determining that the distal home position has been reached, actuating the linear electric motor to move the shuttle mechanism to a proximal home position; determining that the proximal home position has been reached based on feedback from the position sensor assembly and the linear electric motor; and A method comprising:

17. The method of claim 16 , wherein determining that the distal home position has been reached includes monitoring voltages at a distal position sensor and a proximal position sensor.

18. The method of claim 16 , further comprising calibrating the position sensor assembly based on voltage readings at the distal home position and the proximal home position.

19. 1. A method of operating an impact tool, the method comprising: detecting activation of a trigger mechanism to initiate an impact from the impact tool; determining a position of a shuttle assembly within a housing of the impact tool, the shuttle assembly including a component adapted to generate an impact; determining an intended impact direction from a position of the shuttle assembly; applying an impact in the intended impact direction by actuating a linear electric impact mechanism; A method comprising:

20. 20. The method of claim 19, further comprising, after applying the impact, determining whether to apply the impact repeatedly based on a position of the trigger mechanism.

21. 21. The method of claim 20, further comprising: upon determining not to repeatedly apply the impact, stopping the linear electric impact mechanism.

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