Surgical instrument cable coatings and systems and methods of making same

Abstract

A surgical instrument includes a pulley rotatable about a pivot pin and an end effector coupled to the pivot pin. The instrument also includes a cable at least partially wrapped around the pulley and configured to actuate the end effector. The cable and / or any pulley component (e.g., pulley, pivot pin, etc.) includes a first coating having tungsten disulfide.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 445,048, filed February 13, 2023, the entire contents of which are incorporated herein by reference. Background Art

[0003] Surgical instruments utilize various mechanisms to actuate and articulate the end effector. With the advent of surgical robotic systems and handheld powered instruments, cable actuation mechanisms have become increasingly common. However, cables are susceptible to failure during manipulation as they are pulled under high loads onto pulleys and other mechanisms used to constrain and redirect the cables. As a result, localized wear of the cables occurs due to the high pressures between the sliding surfaces within the twisted cable filaments and between the cable and the pulley surfaces. Conventional lubricants are removed during sterilization processes that may involve steam, solvents, high temperatures, etc. Given the multiple uses and sterilizations that instruments undergo, the amount of lubricant on the cable decreases with each use and sterilization. Therefore, there is a need for a lubricated cable suitable for use with robotic or powered surgical instruments that is capable of withstanding one or more sterilization cycles. Summary of the Invention

[0004] The present disclosure provides coatings and methods for forming coatings on cables used in surgical instruments. The cables can be multifilament cables formed from any suitable metal, such as tungsten. The coating lubricates the cable and the individual filaments, thereby reducing frictional wear, increasing the hardness of the wear surface, and reducing scratching. The coating also provides corrosion resistance and chemical resistance, which allows the surgical instruments to undergo multiple reprocessing cycles.

[0005] According to one embodiment of the present disclosure, a surgical instrument is disclosed. The surgical instrument includes a pulley rotatable about a pivot pin and an end effector coupled to the pivot pin. The instrument also includes a cable at least partially wound around the pulley and configured to actuate the end effector. The cable includes a first coating comprising tungsten disulfide.

[0006] Implementations of the above embodiments may include one or more of the following features. According to one aspect of the above embodiments, the first coating has a hardness of approximately 35 on the Rockwell C hardness scale (HRC). The first coating may be disposed on a higher hardness base coating having a hardness greater than 35 HRC. The harder base coating is configured to improve the surface wear properties of the cable.

[0007] The harder base coating may include, but is not limited to, at least one of the following materials: titanium nitride, titanium, nickel, nickel boron, nickel-polytetrafluoroethylene, chromium, chromium nitride, chromium nickel, zirconium nitride, amorphous carbon, boron, boron carbide, molybdenum disulfide, molybdenum, graphite, silicone, or zirconium oxide. The first coating may have a static coefficient of friction of approximately 0.6 or less and a dynamic coefficient of friction of approximately 0.3 or less. The first coating may have a uniform thickness of approximately 0.0005 mm to approximately 0.05 mm. The cable may further include a second coating disposed over the first coating. The second coating may include a polymer that may include, but is not limited to, at least one of polytetrafluoroethylene, tetrafluoroethylene, perfluoroalkoxyalkane, fluorinated ethylene propylene, polyimide, polyethyleneimine, polyoxymethylene, polyetheretherketone, a copolymer, or a combination thereof. The cable may further include a third coating disposed over the second coating. The third coating may include at least one or more of the following: a wax-based lubricant, a paraffin-based lubricant, a grease-based lubricant, or an oil-based lubricant, which may include, but is not limited to, at least one of the following: graphite, petroleum, PTFE, TFE, molybdenum, polyalphaolefin (PAO), polyalkylene glycol (PAG), and / or silicone. All material coating types and combinations may also be used and incorporated into any portion of the pulley component.

[0008] According to another embodiment of the present disclosure, a system for coating a surgical instrument cable is disclosed. The system includes a mold having a first portion and a second portion, the first portion and the second portion defining a mold cavity configured to receive the surgical instrument cable. The mold cavity may include a plurality of stops extending along the length of the mold cavity. The system also includes a source of liquid material for forming a coating on the surgical instrument cable within the mold cavity; and one or more gates configured to distribute the liquid material through the mold cavity to form a smooth, thin, and uniform coating on the surgical instrument cable.

[0009] Implementations of the above embodiments may include one or more of the following features. According to one aspect of the above embodiments, each of the plurality of stops may be arranged in a parallel configuration relative to the other stops along the length of the mold cavity. Each of the plurality of stops may also be arranged in a spiral configuration along the length of the mold cavity to assist in mold flow and mold application processes. The first and second portions of the mold may contact each other along a parting line, and the mold cavity may further include a first pair of channels arranged along the parting line and a second pair of channels arranged in a plane perpendicular to the parting line. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Various embodiments of the present disclosure are described herein with reference to the accompanying drawings, in which:

[0011] Figure 1is a side view of a cable according to the present disclosure;

[0012] Figure 2 yes Figure 1 A transverse cross-sectional view of a cable;

[0013] Figure 3 is a perspective view of an instrument drive unit and a surgical instrument according to an embodiment of the present disclosure, wherein the components are separated;

[0014] Figure 4 According to the embodiment of the present disclosure Figure 3 A top perspective view of an end effector of a surgical instrument;

[0015] Figure 5 According to the embodiment of the present disclosure Figure 1 A transverse cross-sectional view of the cable and an enlarged view thereof;

[0016] Figure 6 is a schematic diagram of an injection molding gate manifold according to an embodiment of the present disclosure, depicting the gate manifold for overmolding. Figure 1 One or more gates for the cable;

[0017] Figure 7 According to one embodiment of the present disclosure Figure 4 A transverse cross-sectional view of a mold of a coating system;

[0018] Figure 8 According to another embodiment of the present disclosure Figure 4 A transverse cross-sectional view of a die of a coating system; and

[0019] Figure 9 is a coating according to one embodiment of the present disclosure Figure 1 Flowchart of a method for wiring a cable. DETAILED DESCRIPTION

[0020] Various embodiments of the present disclosure are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views.

[0021] The present disclosure provides cables for use with surgical instruments, particularly surgical robots and powered instruments, which place high loads on the cables that actuate and articulate the end effectors of the surgical instruments. Figure 1 and Figure 2As shown, the cable 10 is a multifilament cable and includes a plurality of individual filaments 14 braided into a plurality of bundles 12, each bundle including a plurality of filaments 14. The bundles 12 may be formed by braiding, twisting, etc., of the filaments 14, and the cable 10 may, in turn, be formed by braiding, twisting, etc., of the bundles 12. The cable 10 may also include a ferrule 11 or crimped end to secure the bundles 12 and filaments 14.

[0022] The bundle 12 may include any suitable number of filaments 14, which may be from about 6 to about 40. The bundle 12 may include any suitable number of filaments 14. Figure 1 1 and 2. The same different number of filaments 14 is shown in the figure, which shows a 19×19 cable 10 (nineteen bundles 12, each bundle having nineteen filaments 14). In an embodiment, some of the bundles 12 may include different numbers of filaments 14, and the bundles 12 may be arranged in any suitable manner so that the bundles 12 with a smaller number of filaments 14 may be used to form the core of the cable 10, while the larger bundles 12 are woven around the central core. The filaments 14 may be drawn from any suitable metal (such as tungsten, stainless steel, etc.). The diameter of the filaments 14 may be from about 0.001 mm to about 0.002 mm. The diameter of the cable 10 may be from about 0.4 mm to about 1 mm, depending on the number of filaments 14, bundles 12 described above, their corresponding diameters and configuration.

[0023] The cable 10 according to the present disclosure may be used with any cable-actuated surgical instrument, such as Figure 3 and Figure 4 150 of the instrument. Figure 3 The instrument 150 is actuated by an instrument drive unit (IDU) 170, which is configured to transmit power and actuation force from its motors 152a, 152b, 152c, and 152d to the instrument 150 to drive the instrument 150, such as articulating, rotating, pitching, swaying, clamping, cutting, etc. The IDU 170 can be disposed on a robotic arm or a handheld platform. The IDU 170 can also be configured to activate various functions of the instrument 150, such as firing staples, advancing the blade, supplying electrosurgical energy, etc.

[0024] The IDU 170 includes a motor group 151 and a sterile barrier housing 130. The motor group 151 includes motors 152a, 152b, 152c, 152d for controlling various operations of the instrument 150. The instrument 150 is removably coupled to the IDU 170. When the motors 152a, 152b, 152c, 152d of the motor group 151 are actuated, the rotation of the drive transmission shafts 154a, 154b, 154c, 154d of the motors 152a, 152b, 152c, 152d, respectively, is transmitted to the drive assembly of the instrument 150. The instrument 150 is configured to convert the rotational force / movement supplied by the IDU 170 (e.g., via the motors 152a, 152b, 152c, 152d of the motor group 151) into longitudinal movement or translation of the cable or drive shaft to achieve the end effector 200 ( Figure 4 )’s various functions.

[0025] Each of motors 152a, 152b, 152c, and 152d includes a current sensor 153, a torque sensor 155, and an encoder sensor 157. For simplicity, only the operation of motor 152a will be described below. Sensors 153, 155, and 157 monitor the performance of motor 152a. Current sensor 153 is configured to measure the current consumption of motor 152a, and torque sensor 155 is configured to measure motor torque. Torque sensor 155 can be any force or strain sensor including one or more strain gauges configured to convert mechanical force and / or strain into a sensor signal indicating the torque output by motor 152a. Encoder sensor 157 can be any device that provides a sensor signal indicating the number of revolutions of motor 152a, such as a mechanical encoder or an optical encoder. Parameters measured and / or determined by encoder sensor 157 can include speed, distance, revolutions per minute, position, and the like. Sensor signals from sensors 153, 155, 157 are transmitted to IDU 170, which then controls motors 152a, 152b, 152c, 152d based on these sensor signals. Specifically, motors 152a, 152b, 152c, 152d are controlled by actuator controller 159, which controls the output torque and angular velocity of motors 152a, 152b, 152c, 152d. In embodiments, additional position sensors may also be used, including but not limited to potentiometers, Hall effect sensors, accelerometers, and gyroscopes coupled to the movable component and configured to detect travel distance.

[0026] refer to Figure 3, the instrument 150 includes an adapter 160 having a housing 162 at a proximal end portion thereof and an elongated shaft 164 extending distally from the housing 162. The housing 162 of the instrument 150 is configured to be selectively coupled to the IDU 170 of the robot to enable the motors 152a, 152b, 152c, 152d of the IDU 170 to operate the end effector 200 of the instrument 150. The housing 162 of the instrument 150 supports a drive assembly that mechanically and / or electrically cooperates with the motors 152a, 152b, 152c, 152d of the IDU 170. The drive assembly of the instrument 150 may include any suitable electrical and / or mechanical components to achieve driving force / movement.

[0027] The surgical instrument also includes an end effector 200 coupled to the elongated shaft 164. The end effector 200 may include any number of degrees of freedom that allow the end effector 200 to articulate, pivot, etc. relative to the elongated shaft 164. The end effector 200 may be any suitable surgical end effector configured to treat tissue, such as a dissector, grasper, sealer, stapler, etc. Figure 4 As shown, the end effector 200 may include a pair of opposing jaws 220 and 222 that are movable relative to each other. In an embodiment, the end effector 200 may include a proximal portion 212 having a first pin 213 and a distal portion 214. The end effector 200 may be actuated using a plurality of cables 10 that pass through the proximal portion 212 and the distal portion 214 around their respective pulleys 212a, 212b, 214a, 214b, which are integrally formed as arms of the proximal portion 212 and the distal portion 214. In an embodiment, the end effector 200 (i.e., the distal portion 214 and the jaws 220 and 222) may be articulated about an axis "AA" to control the left-right swing angle of the end effector relative to the longitudinal axis "XX". The distal portion 214 includes a second pin 215, to which the pair of jaws 220 and 222 are pivotally coupled. The jaws 220 and 222 are configured to pivot about an axis "BB" defined by the second pin 215 to allow control of the pitch angle of the jaws 220 and 222 and opening and closing the jaws 220 and 222. The yaw, pitch, and jaw angle are controlled by adjusting the tension and / or length and direction (e.g., proximal or distal) of the cable 10. Thus, the end effector 200 can have three degrees of freedom: yaw, pitch, and jaw angle between the jaws 220 and 222.

[0028] refer to Figure 2, the cable 10 also includes a coating 20. The coating 20 can also be applied to components of the instrument 150 that contact the cable 10, such as the pulleys 212a, 212b, 214a, 214b. The coating 20 lubricates the cable 10 and the individual filaments 14 and components of the instrument 150 to reduce frictional wear, thereby increasing the hardness of the wear surface and reducing galling.

[0029] The coating 20 can be applied to the cable 10 using overmolding, extrusion, compression molding, spraying, electroplating, electroless plating, or by a vapor deposition process. The material is applied to the interstitial spaces, gaps, and other surface textures inherent in multi-filament twisted cables. The coating 20 can have a thickness of about 0.0005 mm to about 0.05 mm. The relatively low thickness allows for minimally invasive device mechanisms and instruments (such as Figure 3 and Figure 4 The coating 20 of the present disclosure may have a static coefficient of friction of approximately 0.6 or less and a kinetic coefficient of friction of approximately 0.3 or less.

[0030] WS2 provides excellent metal-to-metal bonding and adhesion to the cable substrate. The application process does not affect the substrate or base material, which is a major advantage over most heat-curing coatings or electroplated coatings. These heat-curing coatings require adhesives and temperatures that may change the temper and hardness of the substrate. These electroplated coatings may induce hydrogen embrittlement and often require an oven tempering process to relieve stress in the substrate. WS2 coatings also provide excellent chemical stability as well as corrosion and chemical resistance. This property allows the coating to withstand multiple sterilization and reprocessing cycles that may include extreme pH environments. In addition, WS2 coatings have an operating temperature of approximately 650°C, which provides a significant margin over autoclave temperatures, which can reach as high as approximately 137°C.

[0031] Furthermore, the coating 20 comprising WS2 is applied as a dry film that does not migrate or creep due to the expected heat and pressure during use and / or sterilization or reprocessing cycles. During sterilization and reprocessing, the device 150 and its components are exposed to a variety of chemical cleaning agents, which may include alkaline and enzymatic detergents. As described above, the chemical resistance of WS2 prevents chemical interaction or physical scrubbing of the coating 20 in the presence of these chemicals. In particular, the coating 20 resists interaction with proteases, amylases, and lipases used in enzymatic detergents. Furthermore, the coating 20 also tolerates the high pH of alkaline detergents, which may have a pH of 10 to 11. During reprocessing, the device 150 may also be lubricated using conventional lubricants, such as water-based lubricants containing propylene glycol or mineral oil. The chemical resistance of WS2 also provides protection from such lubricants due to its resistance to interaction with mineral oil and alcohols.

[0032] The WS2 coating is also inert, non-toxic and biocompatible for use in devices within the human body. The hardness of the WS2 coating can be about 35 on the Rockwell C hardness scale (HRC). When used in combination with other materials or harder alloy substrate coatings, wear resistance can be improved, thereby providing a higher hardness property of up to 70HRC below the WS2 coating, thereby providing additional wear protection. Suitable substrate alloys and coating materials can include, but are not limited to, titanium nitride, titanium, nickel, nickel boron, nickel-polytetrafluoroethylene (PTFE), chromium, chromium nitride, chromium nickel, zirconium nitride, amorphous carbon, boron, boron carbide, molybdenum disulfide, molybdenum disulfide, molybdenum, graphite, silicone, zirconium oxide, and combinations thereof. Therefore, the coating 20 can also include a hard material substrate surface that prevents accelerated wear and degradation caused by high sliding surface pressures between the twisted bundle 12 and the filaments 14 in the cable 10 and between the cable 10 and the pulley surface. The materials and coatings used target maximum surface hardness, optimal tensile and elongation properties for the bundles 12 and filaments 14 of the cable 10 and the pulleys.

[0033] To prevent galling, the nominal difference in surface hardness between the cable 10 and any mating pulleys or any other mating, supporting, restraining, sliding, or manipulating components of the instrument 150 may be about 5 HRC or greater. The coating 20 may be used to reduce the hardness variation between the two mating components.

[0034] Because cables are more susceptible to fatigue and failure, it is desirable that pulleys and all other components that interact with the cable be made with a lower surface hardness, making them sacrificial wear parts between the two mating components. Therefore, the cable 10 can have a higher coating surface hardness than the pulleys and other mating components.

[0035] Figure 5A multilayer coating 30 is shown, which is a combination coating of multiple materials and includes multiple layers (i.e., two or more layers) of coating, each layer of which is formed of a different material. Like coating 20, coating 30 can be applied to cable 10 or to a mating pulley and / or cable component. Coating 30 includes a base coating 31 formed of one or more hard and / or low-friction coating materials, including but not limited to the following materials and / or alloy combinations: titanium nitride, titanium, nickel, nickel boron, nickel-polytetrafluoroethylene (PTFE), chromium, chromium nitride, chromium nickel, zirconium nitride, amorphous carbon, boron, boron carbide, molybdenum disulfide, molybdenum, graphite, silicone, or zirconium oxide. Base coating 31 has higher hardness properties than subsequent coatings applied over base coating 31 (i.e., first coating 32 formed of WS2).

[0036] The first coating 32 is substantially similar to the coating 20 and is applied over the base coating 31. The first coating 32 can be applied to a thin and uniform thickness by overmolding, extrusion, compression molding, spraying, electroplating, electroless plating, or by a vapor deposition process, which can be from about 0.0005 mm to about 0.05 mm. The combination of alloy coatings also improves the hardness of the wear surface of the cable 10 or any of the mating pulleys and / or cable components. The improved hardness of the first coating 32 improves the wear characteristics of the coated surface and provides a smoother overall surface finish and roughness of the stretched cable outer surface to support reduced surface friction and surface porosity, thereby reducing wear and improving the sliding efficiency of the cable and any mating components thereof.

[0037] The multilayer coating 30 also includes a second coating 34 formed from a polymer material. The second coating 34 is disposed over the first coating 32. The second coating 34 is formed from a hard polymer material and provides a lubricated sacrificial wear surface to protect the cable 10, which should not creep or migrate away from the primary wear and bearing surfaces within the cable pulley mechanism or assembly. The second coating 34 can be applied using overmolding, extrusion, compression molding, spraying, or vapor deposition processes and can have a thickness of approximately 0.01 mm to approximately 0.2 mm. Suitable polymers for the second coating 34 can have a melting point of 140°C or higher to withstand the temperatures encountered during autoclaving. The polymers also have ultra-low friction, high heat distortion temperature (HDT) characteristics, and high pressure-velocity (PV) properties. Suitable polymers include, but are not limited to, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), perfluoroalkoxyalkanes (PFA), fluorinated ethylene propylene (FEP), polyimides, polyethyleneimine (PEI), polyoxymethylene (POM), polyetheretherketone (PEEK), copolymers, and combinations thereof. Glass or carbon fiber additives may also be added to improve the HDT or PV properties of the polymer-based second coating 34 .

[0038] In addition, the multi-layer coating 30 includes a third coating 36 formed from a dry and / or solid and / or liquid lubricant, including but not limited to silicone, petroleum, graphite, synthetic greases or oils. The third coating 36 can also be applied using overmolding, extrusion, compression molding, spraying, or vapor deposition processes and can have a thickness of about 0.01 mm to about 0.2 mm. The third coating 36 provides a smoother overall surface finish and reduces the roughness of the outer surface of the cable 10 to support reduced surface friction and surface porosity. The additional lubricity reduces wear and improves the sliding efficiency of the cable 10 and any mating components thereof.

[0039] The multi-layer coating 30 provides protection for the instrument cable 10 and / or any substrate used in any of the mating pulleys and / or cable components from the extreme chemical environments and temperatures of autoclave steam sterilization cycles. These protective coatings also prevent or reduce the chemical and corrosive degradation expected from these processes, which helps maintain the functional efficiency of the surgical instrument cable 10 and extend its functional working life and reliability.

[0040] In an embodiment, only some of the coatings 31, 32, 34, 36 may be used, i.e., one to three coatings may be skipped. Thus, the coatings 31, 32, 34, 36 may be applied individually, or if applied together, the coating with the higher hardness may be applied initially, with the coating with the lower hardness being applied over the harder coating, as described above with respect to Figure 5 Thus, when coating 32 of WS2 is applied, it may be subsequently coated with coating 34 and / or coating 36. However, if both coatings 34 and 36 are used, coating 34 is applied first, followed by coating 36. Similarly, coating 31 (if applied) is applied first, followed by coating 32. Thus, coatings 31, 32, 34, 36 are applied based on their relative hardness, as shown in FIG. Figure 5 The layers are shown to be applied sequentially, with the hardest coating (eg, coating 31) being applied first, followed by the second hardest coating (eg, coating 32), and so on.

[0041] refer to Figures 6 to 8 , the coating system 40 can be used to form the second (i.e., polymer) coating layer 34 and / or the third coating layer 36 of the multi-layer coating 30. The coating system 40 can be used in any molding process, such as overmolding, injection molding, gravity molding, or extrusion. The coating system 40 includes a mold 42 having a first portion 43 and a second portion 44 defining a mold cavity 46 therein, such as Figure 7 and Figure 8As shown. Mold cavity 46 has a substantially circular cross-section to match the cross-section of cable 10 and has a diameter slightly larger than the diameter of cable 10. Mold cavity 46 defines a parting line 47 at which first portion 43 and second portion 44 contact each other in a liquid-tight manner. In an embodiment, mold cavity 46 may be larger than the diameter of cable 10, depending on the desired thickness of the applied coating, for example, from about 0.01 mm to about 0.2 mm. Mold portions 43 and 44 are opened, and cable 10 is loaded therein, with ferrule 11 extending outside mold 42.

[0042] refer to Figure 7 and Figure 8 , the mold cavity 46 can have a plurality of stops 48 disposed therein to constrain and center the cable 10 within the mold cavity 46. The stops 48 can extend the entire length of the mold cavity 46. The stops 48 assist in the flow of material around the cable 10 to properly fill interstitial spaces within the cable, and can protrude into the mold cavity 46 by approximately 0.01 mm or more. The stops 48 can be integrally formed with the first portion 43 and the second portion 44 and can be evenly spaced in a consistent pattern, or can be staggered along the circumference of the mold cavity 46. In an embodiment, each of the stops 48 can have paired, diametrically opposed stop ribs 48, for example, 180° apart.

[0043] The stop 48 can be straight, i.e., parallel to the longitudinal axis defined by the mold cavity 46, or spiral-shaped to assist in the flow of the polymer material. The stop 48 can also be arranged in a uniform pattern or staggered. The stop 48 is configured to center the cable 10 within the mold cavity and can contact or have a slight interference fit with the cable 10 and can be spaced apart from the cable 10 by about 0.01 mm or less.

[0044] refer to Figure 8 , shows another embodiment of a mold 42 having one or more channels 49 for assisting material flow during the overmolding process. The channels 49 can be arranged along the parting line 47 and / or in a plane perpendicular to the parting line 47, as shown in FIG. Figure 8 As shown. After the molding process, the material fills the channels 49 to form fins, which are trimmed in post-processing. Placing the channels 49 approximately 180° apart simplifies the trimming process. However, the channels 49 can be placed along any portion of the circumference of the mold cavity 46.

[0045] refer to Figure 6, the material for forming the second (i.e., polymer) coating 34 is provided to the mold 42 from a material source 51 (e.g., a heated tank) through a main mold gate runner 50, which is coupled to a gate manifold 52 that feeds one or more sub-gates 54, each of which is in turn coupled to the mold 42 at a corresponding plurality of locations. This configuration allows the mold 42 to be filled in a consistent and uniform manner. The mold gates can include single gates, vertical gates, or axial gates. The number of sub-gates can be increased based on the cable length to reduce gate pressure and optimize overmolding filling of interstitial spaces within the cable 10.

[0046] refer to Figure 9 , discloses a method for applying a second coating 34. At step 100, the cable 10 is loaded into the mold 42 by opening the first portion 43 and the second portion 44, placing the cable 10 into the mold cavity 46, and securing the mold 42 around the cable 10. At step 102, the coating material is melted to form a liquid composition suitable for the molding process and supplied to the mold 42 via the gate manifold 52 at step 104. During step 104, the flow of the liquid material can be controlled by any suitable mechanism until the liquid material has sufficiently entered the mold cavity 46. At step 106, the mold 42 is cooled to allow the second coating 34 to form. At step 108, the cable 10 and the coating are removed and post-processed to remove the protrusions formed by the channels 49.

[0047] In the embodiment where multiple coating layers 34 and 36 of the multi-layer coating 30 are applied, the coating layers 34 and 36 may be applied repeatedly. Figure 9 The coated cable 10 is processed to form each of the coatings 34 and 36 using a process described above. Thus, after forming the first coating 32, the coated cable 10 is processed again to form the second coating 34, and so on. This can be achieved by using a material (e.g., WS2) for the first coating 32 that has a higher melting point than the material (e.g., the polymers listed above) for the second coating 34. Thus, the material (e.g., grease or oil) for the third coating 36 has a lower melting point than the material for the second coating 34.

[0048] It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be interpreted as limiting, but merely as illustration of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the appended claims.

Claims

1. A surgical instrument comprising: a pulley rotatable about a pivot pin; an end effector coupled to the pivot pin; as well as A cable is wound at least partially around the pulley and configured to actuate the end effector, wherein the cable includes a first coating comprising tungsten disulfide.

2. The surgical instrument according to claim 1, wherein: The first coating has a hardness of about 35 on the Rockwell C hardness scale (HRC).

3. The surgical instrument according to claim 1, wherein: The first coating is applied on a base coating provided on the applied cable, wherein the base coating has a hardness higher than 35 HRC.

4. The surgical instrument according to claim 3, wherein the material of the base coating is selected from the group consisting of: titanium nitride, titanium, nickel, nickel boron, nickel-polytetrafluoroethylene, chromium, chromium nitride, chromium nickel, zirconium nitride, amorphous carbon, boron, boron carbide, molybdenum disulfide, molybdenum disulfide, molybdenum, graphite, silicone and zirconium oxide.

5. The surgical instrument according to claim 3, wherein: The cable includes a second coating disposed on the first coating, the second coating including a polymer.

6. The surgical instrument according to claim 5, wherein: The polymer is selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene, perfluoroalkoxyalkanes, fluorinated ethylene propylene, polyimides, polyethylene imines, polyoxymethylene, polyetheretherketones, copolymers, and combinations thereof.

7. The surgical instrument according to claim 5, wherein: The cable further includes a third coating layer disposed on the second coating layer, the third coating layer including at least one of a wax-based lubricant, a paraffin-based lubricant, a grease-based lubricant, or an oil-based lubricant.

8. The surgical instrument according to claim 1, wherein: At least one of the pulley or the pivot pin includes the first coating comprising tungsten disulfide.

9. The surgical instrument according to claim 1, wherein: At least one of the cable, the pulley, or the pivot pin includes a multi-layer coating having the first coating as one of its layers.

10. The surgical instrument according to claim 1, wherein: The first coating has a static coefficient of friction of about 0.6 or less and a kinetic coefficient of friction of about 0.3 or less.

11. The surgical instrument according to claim 1, wherein: The first coating has a uniform thickness of about 0.0005 mm to about 0.05 mm.

12. A system for coating a surgical instrument cable, the system comprising: a mold comprising a first portion and a second portion defining a mold cavity, the mold cavity being configured to receive the surgical instrument cable, wherein the mold cavity comprises a plurality of stops extending along a length of the mold cavity; a source of liquid material for forming a coating on the surgical instrument cable within the mold cavity; and A gate manifold is configured to distribute the liquid material through the mold cavity to form the coating on the surgical instrument cable.

13. The system according to claim 12, wherein: Each of the plurality of stops is arranged in a parallel or spiral configuration relative to the other stops along the length of the mold cavity.

14. The system according to claim 12, wherein: The first portion and the second portion contact each other along a parting line, and the mold cavity further includes a first pair of channels disposed along the parting line and a second pair of channels disposed in a plane perpendicular to the parting line.

15. The system according to claim 12, wherein: The coating comprises a polymer.

16. The system according to claim 15, wherein: The polymer is selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene, perfluoroalkoxyalkanes, fluorinated ethylene propylene, polyimides, polyethylene imines, polyoxymethylene, polyetheretherketones, copolymers, and combinations thereof.

17. A method for coating a surgical instrument cable, the method comprising: placing a surgical instrument cable into a mold, the mold comprising a first portion and a second portion defining a mold cavity, the mold cavity being configured to receive the surgical instrument cable, wherein the mold cavity comprises a plurality of stops extending along a length of the mold cavity; and A liquid material is supplied to the mold cavity to form a coating on the surgical instrument cable.

18. The method according to claim 17, further comprising: placing the surgical instrument cable having the first coating into the mold; as well as A second liquid material is supplied to the mold cavity to form a second coating layer on the first coating layer, wherein the second coating layer includes a polymer.

19. The method according to claim 18, wherein The polymer is selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene, perfluoroalkoxyalkanes, fluorinated ethylene propylene, polyimides, polyethylene imines, polyoxymethylene, polyetheretherketones, copolymers, and combinations thereof.

20. The method of claim 18, further comprising: placing the surgical instrument cable having the first coating and the second coating into the mold; as well as A third liquid material is supplied to the mold cavity to form a third coating layer on the second coating layer, wherein the third coating layer includes at least one of a wax-based lubricant, a paraffin-based lubricant, a grease-based lubricant, or an oil-based lubricant.

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