Operating rope

Abstract

To provide an operation rope 1 of a medical device that has a remarkably excellent torque transmission property.SOLUTION: An operation rope 1 has a core element wire 4 and six side element wires 6. Each side element wire 6 is spirally wound around the core element wire 4. The operation rope 1 has a layer twisting structure of "1+6". At least one of the element wires is coated with resin. A method for manufacturing the operation rope 1 of a medical device obtains a metal element wire by drawing a metal material, coats the metal element wire with resin, and subsequently twists the metal element wires together and applies heat processing at a temperature equal to or lower than melting temperature of the resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control rope suitable for medical equipment. [Background technology]

[0002] In endoscopic treatment tools, an operating rope is used to transmit operations at the operator's hand to a treatment section at the tip. Japanese Patent Application Laid-Open Publication No. 8-126648 discloses an endoscopic treatment tool. In the treatment tool, the treatment section is inserted into a patient's body cavity, and the operating wire rope transmits pushing and pulling forces and rotational forces (torque) from the operating section at the operator's hand to the treatment section at the tip. The transmitted forces allow the treatment section to reach the treatment target site, and medical treatment is performed. The operating rope is required to transmit operations at the operator's hand without delay. In particular, it is required to have torque transmission capabilities (rotational tracking capabilities) that transmit rotational operations at the operator's hand without delay. Furthermore, flexibility is required when the endoscope is inserted into a bent part inside the body.

[0003] JP 2019-44305 A discloses an operating rope having twisted side wires. This operating rope has excellent torque transmission properties and is flexible.

[0004] Japanese Patent Application Laid-Open No. 2005-13296 discloses an operating rope in which an outer layer of parallel-twisted upper twist and a lower layer of first twist are twisted together, and the outer periphery of the outer twisted layer is resin-coated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-126648 [Patent Document 2] JP 2019-44305 A [Patent Document 3] JP 2005-13296 A Summary of the Invention [Problem to be solved by the invention]

[0006] With the development of medical equipment, there is a demand for even better torque transmission properties for operating ropes. The present invention provides an operating rope for medical equipment that has even better torque transmission properties. [Means for solving the problem]

[0007] The operating rope for medical devices according to the present invention has a layered twist structure having a core wire and side wires twisted helically around the core wire, and at least one of the wires is coated with resin.

[0008] Preferably, the wire whose periphery is covered with resin is a core wire.

[0009] Preferably, the resin is a fluorine-based resin.

[0010] Preferably, the resin coating thickness is 1 μm or more and 100 μm or less.

[0011] Preferably, the wires are made of carbon steel.

[0012] The present invention may also be a method for producing a rope for operating medical devices, which comprises drawing a metal material to obtain metal wires, coating the metal wires with resin, twisting the metal wires together, and subjecting the twisted metal wires to a heat treatment at a temperature equal to or lower than the melting point of the resin. [Effects of the Invention]

[0013] The operating rope according to the present invention has excellent torque transmission properties. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing one embodiment of an operating rope according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing another embodiment of the operating rope according to the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing still another embodiment of the operating rope according to the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing still another embodiment of the operating rope according to the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing still another embodiment of the operating rope according to the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing still another embodiment of the operating rope according to the present invention. [Figure 7] FIG. 7 is a cross-sectional view of a conventional operating rope. [Figure 8] FIG. 8 is a cross-sectional view of another conventional operating rope. [Figure 9] FIG. 9 is a diagram showing a part of a manufacturing process for an operating rope according to the present invention. [Figure 10] FIG. 10 is an explanatory diagram showing a method for measuring the torque transmissibility of the operating rope of FIG. [Figure 11] FIG. 11 is a graph showing the evaluation results of the torque transmissibility of the operating rope measured by the method of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, the present invention will be described in detail based on preferred embodiments, with appropriate reference to the drawings.

[0016] 1 to 6 show enlarged cross-sectional views of several embodiments of the operating wire rope (hereinafter simply referred to as rope) according to the present invention. Each shows a cross section perpendicular to the longitudinal direction of the operating rope. Each of the ropes 1, 5, 9, 13, 17, and 23 is composed of a strand formed by twisting together multiple wires. The wires are made of a metal material. The present invention is not limited to the configurations according to the embodiments shown in FIGS. 1 to 6.

[0017] This operating rope is cut to a predetermined length and used as a component of a medical device. For example, one end is connected to a proximal operating portion of the medical device, and the other end is connected to a treatment portion as a distal end. Pushing, pulling, and torque applied to the proximal portion are transmitted to the distal end via the operating rope. This positions the treatment portion at the treatment site, allowing treatment to be performed. The typical diameter D of the operating rope is 0.3 mm to 5 mm. Figures 7 and 8 show examples of conventional wire ropes. Figure 7 shows a rope without a resin coating on the wires. Figure 8 shows a rope whose outer circumference is coated with an integrated resin 34.

[0018] Rope 1 shown in FIG. 1 is constructed with a 1+6 layer twist consisting of one core wire (core wire) 2 and six outermost layer wires (also called side wires) 3. Resin 4 is coated around the core wire. Rope 5 shown in FIG. 2 is constructed with a 1+6 layer twist consisting of one core wire (core wire) 6 and six outermost layer side wires 7. Resin 8 coats the core wire and three side wires. Rope 9 shown in FIG. 3 is constructed with a 1+6 layer twist consisting of one core wire (core wire) 10 and six outermost layer side wires 11. Resin 12 coats all six side wires. Rope 13 shown in FIG. 4 is constructed with a 1+6 layer twist consisting of one core wire (core wire) 14 and six outermost layer side wires 15. Resin 16 coats the core wire and all six side wires. At least one of the wires of the present invention is resin-coated, improving the sliding properties of the coated portion and making the rope flexible. Because the rope is flexible, there is less energy loss when the rope transmits rotation in a bent state, making it easier to transmit rotational force from the base end to the tip, and it has been found that torque transmission is improved. The effects of the present invention can be achieved if at least one of the core wire and side wires is resin-coated. The configuration shown in Figure 1, in which the core wire is resin-coated, is preferred because the core wire is in contact with all side wires. The configurations shown in Figures 2 and 3, in which there is no metal-to-metal contact between the wires, are even more preferred. The configuration shown in Figure 4, in which all wires are resin-coated, is particularly preferred.

[0019] The rope 7 shown in Figure 5 is constructed with a 1+6+12 layer lay consisting of a core strand 21, which is the lower layer of the 1+6 layer lay, and 12 side wires 20. In this rope 17, side wires 20 of a different diameter than the lower layers are used in the outermost layer to make the cross-sectional shape closer to a circle, but all side wires may have the same diameter. The core wire 18 is coated with resin. In Figure 8, the side wires in the outermost layer have the same diameter as the side wires in the lower layers and are tightly twisted together. All wires are coated with resin. All of these are suitable twist configurations for operating ropes, but they are not limited to these.

[0020] The resin used for coating may be a thermosetting resin such as a polyimide resin, or a thermoplastic resin such as a polyurethane. Fluororesins are preferred from the viewpoints of lubricity, biocompatibility, chemical resistance, and the like. Examples of fluororesins include polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoroethylene-propene copolymer (FEP), and polyvinylidene fluoride (PVDF). PTFE is particularly preferred from the viewpoint of versatility.

[0021] The thickness of the resin coating is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 80 μm or less, and particularly preferably 10 μm or more and 50 μm or more. If it is less than 1 μm, the slipperiness effect may decrease with repeated use. If it is more than 100 μm, the strength of the entire rope will decrease, the ability to transmit pushing and pulling forces will decrease, and costs will increase more than necessary.

[0022] When a plurality of wires are coated, the types of resin may be the same for each wire or may be different.

[0023] Each wire of this operating rope is made of a metal material. Preferred metal materials include austenitic stainless steels SUS304 and SUS316, and nickel-titanium alloys. The strength is preferably 2000 MPa or more, and more preferably 2500 MPa or more. In addition, carbon steel is an example of the metal material for each wire. Carbon steel can be made stronger than stainless steel. The strength is preferably 3000 MPa or more, and more preferably 3500 MPa or more. From the perspective of medical use, it is preferable that the carbon steel wire is coated with resin. Of course, the material is not limited to these materials.

[0024] This operating rope 1 is manufactured by the following method, but is not limited to this. The manufacturing process consists of the wire drawing process, resin coating process, drying and heat treatment process, stranding process, and straightening and heat treatment process. In the resin coating and drying and heat treatment processes, resin coating can be achieved by applying resin, immersing in resin liquid or resin dispersion, or spraying resin liquid or resin liquid dispersion. Alternatively, a method of simultaneously extruding molten resin and metal may be used. The resin-coated wires are dried as needed. They may be heated in a heat treatment furnace after drying. The drying and heat treatment process may be omitted. The resin coating process may be performed continuously, as shown in Figure 9. The wires 2 wound around a reel 36 pass through a coating tank 37 containing resin liquid or a coating liquid with resin dispersion, where they are dried, heated in a heat treatment furnace 38, and wound onto a reel 39. In the stranding process, the resin-coated wires are used as core wires and twisted together with uncoated wires to form a rope. In the twisting process, a twisting machine is used. Examples include a tubular type twisting machine and a buncher type twisting machine. In the straightening heat treatment process, tension is applied to the rope, and the rope is straightened by heat treatment. The heat treatment temperature is preferably lower than the melting point of the resin.

[0025] The material of the side wires may be the same as or different from the material of the core wires. Furthermore, the materials of the side wires may be the same as or different from each other. The tensile strength of the core wires and side wires is preferably 2000 MPa or more, more preferably 2500 MPa or more, and particularly preferably 2800 MPa or more. [Example]

[0026] The effects of the present invention will be clarified by the following examples, but the present invention should not be construed as being limited based on the descriptions of these examples.

[0027] [Example 1] The steel material, SUS304, was drawn using a die to obtain a wire with a diameter of 0.25 mm. The tensile strength of this wire was 2800 MPa. This wire was coated with polytetrafluoroethylene (PTFE) by a dipping method. The coating thickness was 10 μm. The coated wire was used as a core wire, and one core wire and six SUS304 side wires with a diameter of 0.23 mm were fed into a tubular-type twisting machine to obtain a twisted wire having the structure shown in FIG. 1. The twisting pitch of this twisted wire was 5.5 mm. This twisted wire was straightened in a continuous heat treatment furnace at a temperature of 250°C to obtain the operating rope of Example 1.

[0028] [Example 2] As in Example 1, a PTFE-coated wire with a wire diameter of 0.25 μm was obtained. Seven of these wires were used in a tubular-type twisting machine to obtain a rope with the 1+6 configuration shown in Figure 3. The twist pitch of this twisted wire was 5.5 mm. This twisted wire was subjected to continuous heat treatment at a temperature of 250°C to straighten it, yielding the operating rope of Example 2.

[0029] [Example 3] The carbon steel material was brass-plated and then drawn using a die to obtain a wire with a diameter of 0.25 mm. The tensile strength of this wire was 3200 MPa. This wire was then coated with polytetrafluoroethylene (PTFE) using a dipping method. The coating thickness was 20 μm. The coated wire was used as a core wire, and one core wire and six SUS304 side wires with a diameter of 0.23 mm were fed into a tubular-type twisting machine to obtain a twisted wire having the structure shown in FIG. 1. The twist pitch of this twisted wire was 5.5 mm. This twisted wire was then straightened in a continuous heat treatment furnace at a temperature of 250°C to obtain the operating rope of Example 1.

[0030] [Comparative Example 1] An operating rope having the configuration shown in Figure 7, in which the core wires were not coated with resin, was obtained in the same manner as in Example 1. This was designated Comparative Example 1.

[0031] Comparative Example 2 A PTFE coating was applied to the periphery of the rope of Comparative Example 1 to obtain a coated rope having a circular cross section including the resin-coated portion, which had the same configuration as that shown in Fig. 8. This was designated Comparative Example 2.

[0032] [Evaluation of Torque Transmittance] As shown in Figure 10, torque transmittance is evaluated by the difference in rotation angle between the proximal end of the spiral and the distal end. A rigid pipe having a double spiral, 41, shown in Figure 10, is used. The double spiral 41 may be a single turn rather than a double spiral. A double spiral is preferable because it allows for clearer evaluation differences. The diameter of the double spiral portion 41 is 200 mm. A rotational force is applied to the proximal end 42 of the rope 1 passed through this rigid pipe in the direction indicated by arrow R1. This causes the distal end 43 of the operating rope 1 to rotate as indicated by arrow R2. The rotation angles of the proximal end 42 and the distal end 43 are measured simultaneously.

[0033] Figure 11 is a graph showing the results of torque transmissibility measured using the method of Figure 10. Figure 10 shows the correspondence between the rotation angle at the proximal end of the operating rope and the rotation angle at the distal end at the same time. The dashed line in the graph is a straight line indicating that the difference between the rotation angle at the proximal end and the rotation angle at the distal end is zero. The solid curve in the graph shows an example of a measured operating rope. The difference between the rotation angle at the proximal end and the rotation angle at the distal end is the difference between the dashed line and the solid line on the vertical axis. The smaller the maximum value of the rotation angle difference measured within the range of 0° to 360° of the rotation angle at the proximal end, the better the torque transmissibility.

[0034] Table 1 below shows the maximum angle difference for each rope of Examples 1-3 and Comparative Examples 1 and 2, expressed as a number when the maximum angle difference for Comparative Example 1 is set to 100. Operating ropes with a small index value have excellent torque transmission properties.

[0035] As shown in Table 1, the evaluation results clearly demonstrate the superiority of the present invention.

[0036] [Table 1] [Industrial Applicability]

[0037] The operating rope according to the present invention can be applied to various medical devices. [Explanation of symbols]

[0038] 1, 5, 9, 13, 17, 23... Operating rope 2, 6, 10, 14, 18, 24... Core wire 3, 7, 11, 15, 20, 25... Side wires 4, 8, 12, 16, 22, 27, 34... Resin coating layer 21, 26... Core strand

Claims

1. A medical device operating rope having a layered structure with a core wire and side wires helically twisted around the core wire, the core wire being coated with resin, and all of the side wires at the outermost periphery of the layered structure being uncoated with resin, and all of the side wires in the layered structure being made of austenitic stainless steel and having a tensile strength of 2500 MPa or more.

2. 2. The operating rope according to claim 1, wherein the resin is a fluorine-based resin.

3. 3. The operating rope according to claim 1, wherein the resin coating has a thickness of 1 μm or more and 100 μm or less.

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