CN112587074B

CN112587074B - Endoscope insertion tube and method for processing outer skin layer of endoscope insertion tube

Info

Publication number: CN112587074B
Application number: CN202110227768.2A
Authority: CN
Inventors: 李奕; 杨俊风; 刘红宇
Original assignee: Daichuan Medical Shenzhen Co ltd
Current assignee: Daichuan Medical Shenzhen Co ltd
Priority date: 2021-03-02
Filing date: 2021-03-02
Publication date: 2021-06-22
Anticipated expiration: 2041-03-02
Also published as: CN112587074A

Abstract

The application provides an endoscope insertion tube and a method for processing an outer skin layer of the endoscope insertion tube. The insertion tube of the endoscope comprises a flexible tube body and an outer skin layer. The outer skin layer is wrapped outside the flexible pipe body and comprises at least one first resin strip and at least one second resin strip, and the first resin strip and the second resin strip extend along the axial direction of the flexible pipe body; the hardness of the first resin strip is gradually increased from the front end to the rear end; and/or the hardness of the second resin strip is gradually increased to gradually increase the hardness of the insertion tube. The technical scheme of the application improves the controllability and the movement flexibility of the insertion tube.

Description

Endoscope insertion tube and method for processing outer skin layer of endoscope insertion tube

Technical Field

The present invention relates to the field of endoscopes, and in particular, to an endoscope insertion tube and a method for processing an outer skin layer of the endoscope insertion tube.

Background

With the increasing level of medical care, the demand for endoscopes has also increased dramatically. During the examination, the insertion tube of the endoscope needs to be inserted into the natural orifice of the subject and moved along the natural orifice. In order to achieve flexible and free manipulation of the insertion tube, the insertion tube needs to have a certain hardness to facilitate transmission of torque. However, the insertion tube needs to be relatively flexible, facilitating large-angle bending within the subject, and reducing discomfort of the subject. Therefore, the requirements for hardness and softness of the insertion tube become conflicting points of mutual restriction.

The above information disclosed in this background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not constitute prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

It is an object of the present application to propose an insertion tube of an endoscope, aiming at simultaneously improving the controllability and the mobility flexibility of the insertion tube.

In order to solve the technical problem, the following technical scheme is adopted in the application:

according to one aspect of the present application, there is provided an insertion tube of an endoscope, comprising:

a flexible pipe body;

the outer skin layer is wrapped outside the flexible pipe body and comprises at least one first resin strip and at least one second resin strip, and the first resin strip and the second resin strip extend along the axial direction of the flexible pipe body;

the hardness of the first resin strip is gradually increased from the front end to the rear end, so that the hardness of the insertion tube is gradually increased; and/or the hardness of the second resin strip is gradually increased so that the hardness of the insertion tube is gradually increased.

According to an embodiment of the present application, the first resin strip is plural, and plural first resin strips extend in parallel in an axial direction of the flexible pipe body;

the second resin strip has a plurality ofly, every the second resin strip is located adjacent two between the first resin strip.

According to an embodiment of the present application, the flexible pipe body comprises a spiral pipe;

the first resin strip is spirally wound on the surface of the flexible pipe body to form a plurality of spiral rings; the spiral direction of the first resin strip is opposite to the spiral direction of the spiral pipe;

the shape of the second resin strip is matched with the shape between at least two adjacent spiral rings in the plurality of spiral rings of the first resin strip.

According to an embodiment of the present application, the width of the first resin strip gradually increases from the front end to the rear end; and/or the width of the second resin strip is gradually increased from the front end to the rear end.

According to an embodiment of the present application, the first resin strip includes a plurality of first hardness segments, and the plurality of first hardness segments are sequentially arranged in a direction from the front end to the rear end in an order of hardness from small to large; and/or the second resin strip comprises a plurality of second hardness sections which are sequentially arranged from the front end to the rear end according to the sequence of hardness from small to large.

According to an embodiment of the present application, each of the first resin strip and the second resin strip includes a thermoplastic polyurethane elastomer rubber.

In another aspect of the present application, a method for processing an outer skin layer of an endoscope insertion tube is further provided, including:

extruding a first resin material on a surface of a flexible pipe body during travel of the flexible pipe body to form a first resin strip, wherein an extrusion temperature of the first resin material is within 5 ℃ higher than a curing temperature of the first resin material;

extruding a second resin material between the formed first resin strips to form second resin strips, wherein the curing temperature of the second resin material is 40-60 ℃ lower than that of the first resin material, and the extruding temperature of the second resin material is 20-40 ℃ higher than that of the second resin material;

wherein, from the front end of skin layer to rear end direction, the hardness of first resin strip and/or the second resin strip increases gradually to make the hardness of insert pipe increase gradually.

According to an embodiment of the present application, said extruding a first resin material at a surface of said flexible pipe body to form a first resin strip comprises:

controlling the flexible pipe body to rotate along the axial direction of the flexible pipe body in the advancing process of the flexible pipe body so as to form the spiral first resin strip through injection molding and extrusion;

wherein, the rotation direction of the flexible pipe body is opposite to the spiral direction of a spiral pipe in the flexible pipe body.

According to an embodiment of the present application, after the extrusion of the first resin material, after the formation of the first resin stripes, a cooling process step is added in which a cooling rate is more than 0.5 ℃ per second.

According to an embodiment of the present application, after forming the second resin strip, the flexible pipe body is rotary cooled.

According to an embodiment of the present application, after the second resin strip is formed, the surface of the outer skin layer is smoothed by an annular doctor blade.

In this application scheme, first resin strip and second resin strip amalgamation form the cortex, from the front end of cortex to the rear end direction, because the hardness crescent of first resin strip and/or second resin strip, consequently make the front end pipeline section hardness of the cortex that forms softer, rear end pipeline section hardness pipeline section is great. The harder rear end pipe section is beneficial to transmitting torque to the front end pipe section, and the controllability of the insertion pipe is improved; the softer front end pipe section is beneficial to the flexible bending of the insertion pipe in the detected body. Therefore, the controllability and the moving flexibility of the insertion tube are improved by the technical scheme.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

FIG. 1 is a schematic diagram of an endoscope according to one embodiment.

FIG. 2 is a schematic structural view of an endoscope insertion tube according to an embodiment.

FIG. 3 is a schematic diagram of an end construction of an endoscope insertion tube according to one embodiment.

Fig. 4 is a schematic structural view showing an endoscope insertion tube according to another embodiment.

FIG. 5 is a cross-sectional view of an extrusion apparatus according to one embodiment.

FIG. 6 is a flow chart illustrating a method of processing an endoscope for insertion into an outer skin layer of a tube, according to another embodiment.

Fig. 7 is a schematic diagram showing a structure with an extrusion device and an annular doctor blade according to an embodiment.

FIG. 8 is a cross-sectional view of an extrusion apparatus with a compounding zone, according to an embodiment.

FIG. 9 is a cross-sectional view of an extrusion apparatus with a compounding zone shown in accordance with another embodiment.

The reference numerals are explained below: 1. an insertion portion; 2. an operation section; 11. an insertion tube; 12. a bending section; 21. a control knob; 22. a control button; 111. a flexible pipe body; 112. an outer skin layer; 41. an inner mold; 42. an outer mold; 43. an intermediate die; 432. inserting the cover; 441. a first feed channel; 442. a second feed channel; 452. a second feed cylinder; 451. a first feed cylinder; 46. forming a channel; 47. a mixing area; 471. A mixing bin; 472. a mixed flow channel; 481. a turbulent flow structure; 482. a stirring structure; 4771. a feed guide structure; 49. a heat-insulating layer; 51. a first resin strip; 52. a second resin strip; 61. the mold is scraped.

Detailed Description

While this application is susceptible of embodiment in different forms, there is shown in the drawings and will herein be described in detail only some specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the application and is not intended to limit the application to that as illustrated herein.

Thus, a feature indicated in this specification is intended to describe one of the features of an embodiment of the application and does not imply that every embodiment of the application must have the described feature. Further, it should be noted that this specification describes many features. Although some features may be combined to show a possible system design, these features may also be used in other combinations not explicitly described. Thus, the combinations illustrated are not intended to be limiting unless otherwise specified.

In the embodiments shown in the drawings, directional references (such as up, down, left, right, front, and rear) are used to explain the structure and movement of the various elements of the present application not absolutely, but relatively. These descriptions are appropriate when the elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indication of these directions changes accordingly.

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted.

The preferred embodiments of the present application will be further described in detail below with reference to the accompanying drawings of the present specification.

The present embodiment first provides an insertion tube of an endoscope.

Referring to fig. 1, fig. 1 is a schematic diagram of an endoscope according to an exemplary embodiment.

The endoscope of the present embodiment includes an elongated insertion portion 1 inserted into a subject lumen and an operation portion 2 located at a rear end of the insertion portion 1. The operation unit 2 is connected to the insertion unit 1. Wherein, the front and back directions of the endoscope can be as follows: the end of the endoscope close to the subject is in the front direction, and the end of the endoscope close to the operator is in the rear direction. Here, the subject may be a human, an animal, or other inanimate structure.

The endoscope of the present embodiment may be a disposable endoscope. The disposable endoscope discards the polluted part after use, so that the sanitation degree of the endoscope can be improved, and the safe use of the examinee can be ensured. Since the operation part 2 and the insertion part 1 are contaminated during use, the operation part 2 and the insertion part 1 need to be discarded to ensure safe use of the endoscope.

The operation part 2 is approximately in a handle shape, is convenient for an operator to hold by hands and is convenient for forceful operation. The insertion section 1 includes an insertion tube 11 and a bent portion 12. The insertion tube 11 has a bent portion 12 at its distal end.

In the present application, the front end refers to an end of the insertion tube 11 near the bending portion 12, and the rear end refers to an end of the insertion tube 11 near the operation portion.

From the operating portion 2, a pull wire (not shown) extends, which is drivingly connected to the bending portion 12 through the insertion tube 11. The curved portion 12 is provided with a plurality of serpentine structures rotatably connected to each other. The snake bone structure can rotate freely. The inner side wall of the snake bone structure is provided with a guide groove, and the traction wire penetrates through the guide groove to be connected with the snake bone structure in a traction manner. When the operation part 2 pulls the traction wire, the snake bone structure is driven to rotate or bend, so that the bending direction and the bending angle of the bending part 12 connected with the other end of the traction wire can be controlled. The curved portion 12 is curved to extend, and the insertion tube 11 is guided to move in the lumen.

The operation unit 2 is provided with a control knob 21. The control knob 21 is connected with the traction wire, and the control knob 21 is rotated to pull and move the traction wire. The control knob 21 may be a plurality of hand wheels. A plurality of hand wheels are coaxially arranged up and down. The finger of the operator can be used for poking.

Similarly, the operation unit 2 is provided with a control button 22. The control button 22 is in electrical communication with the pump set of the endoscope. The pump set of the endoscope is used for pumping gas or liquid and the like into the endoscope for the endoscope to use during use. The control button 22 can control the operating state of the pump unit. The working state of the pump group can comprise the switching of the pump group, the adjustment of parameters and the like.

The head end of the bending part 12 is provided with a light source and an image acquisition module. The image acquisition module is used for acquiring and obtaining image information in the cavity of the examinee. The medical staff diagnoses and treats the examinee according to the image information.

The insertion tube 11 is provided between the operation portion 2 and the bending portion 12. The insertion tube 11 has a certain flexibility to facilitate movement of the insertion tube 11 within the subject's lumen. Moreover, the outer surface of the insertion tube 11 is a smooth surface, so that on one hand, the friction force between the insertion tube 11 and the cavity can be reduced; on the other hand, the cavity of the examined person can be protected, and the examined person is prevented from being scratched.

In one embodiment, the insertion tube 11 includes a coaxially disposed helical tube, braid and sheath layer 112; the braided layer is sleeved outside the spiral tube, and the outer skin layer 112 is sleeved outside the braided layer. In other embodiments, the braid may be omitted.

An example of the structure of the insertion tube 11 of the present application will be described in the following examples.

Referring to fig. 2, fig. 2 is a schematic structural view of an endoscope insertion tube 11 according to an embodiment. In one embodiment, the insertion tube 11 of the endoscope includes a flexible tube body 111, an outer skin layer 112, and the outer skin layer 112 is wrapped outside the flexible tube body 111, and the outer skin layer 112 has a rear end near the endoscope operation portion 2 and a front end near the endoscope bending portion 12. The outer skin layer 112 includes at least one first resin strip 51 and at least one second resin strip 52, the first resin strip 51 and the second resin strip 52 extending in the axial direction of the flexible pipe body 111; the hardness of the first resin strip 51 gradually increases from the front end toward the rear end, so that the hardness of the insertion tube 11 gradually increases; and/or the hardness of the second resin strip 52 is gradually increased to gradually increase the hardness of the insertion tube 11.

Here, the flexible pipe body 111 includes a spiral pipe and a braid. Wherein, the mode of processing spiral inner tube and weaving layer can refer to prior art and realize to the technical essential that does not regard as this application. After the spiral tube and the braid are sequentially processed, the outer skin layer 112 is processed.

Here, the first resin strip 51 and the second resin strip 52 are joined together to form the outer skin layer 112. First resin strip 51 and second resin strip 52 are not limited to being linear, and may be curved. The first resin strip 51 and the second resin strip 52 are different in hardness.

Please refer to fig. 3. Fig. 3 is a schematic view showing the end structure of an endoscope insertion tube 11 according to an embodiment. In one embodiment, there are a plurality of the first resin strips 51, and the plurality of the first resin strips 51 extend in parallel in the axial direction of the flexible pipe body 111; the second resin strip 52 is a plurality of, and second resin strip 52 extends along the axial of flexible pipe body 111, and every second resin strip 52 is located between two adjacent first resin strips 51 to splice together with first resin strip 51 and form skin layer 112.

In one embodiment, the number of the first resin strips 51 is 2 to 6. For example 4.

In a specific embodiment, when the first resin strip 51 and the second resin strip 52 extend substantially linearly in the axial direction of the flexible pipe body 111, the first resin strip 51 includes a plurality of first hardness segments, which are arranged in order from the front end to the rear end in the order of increasing hardness; and/or second resin strip 52 includes a plurality of second hardness segments arranged in order from the front end toward the rear end in the order of hardness from small to large.

In one implementation, the plurality of hardness segments (collectively, the first hardness segment and the second hardness segment) may be respectively injection-molded from resin materials of different hardness. In the processing method, a plurality of extruders may be provided, and a plurality of feed channels connected to the plurality of extruders correspondingly adjust the discharge order of the plurality of feed channels so that a plurality of hardness segments are sequentially arranged from the front end to the rear end of the flexible pipe body 111 in the order of hardness from small to large in the process that the flexible pipe body 111 travels in the forming channel 46 of the extrusion apparatus.

In another implementation, first resin strip 51 and/or second resin strip 52 may be formed by mixing at least two resin materials having different hardness, and the mixed resin materials are used for injection molding. By continuously adjusting the mixing ratio of the two resin materials, the hardness of the first resin strip 51 and/or the second resin strip 52 formed by injection molding is gradually increased.

The first resin strip 51 and the second resin strip 52 are both Thermoplastic polyurethane elastomer (TPU) strips. By gradually changing the composition of the TPU, it is achieved that the hardness of the first resin strip 51 and/or the second resin strip 52 is gradually increased.

In one embodiment, the TPU includes a first component, a second component; the hardness of the first component is greater than the hardness of the second component. Here, the first component may include one or more of diisocyanate, polyurea, and the like hard segment component; the second component can comprise soft segment components such as polyester polyol, polyether polyol, polycarbonate diol, polysiloxane diol, and one or more of polycaprolactone, polylactic acid and hydroxyl-terminated polybutadiene with hydroxyl at both ends.

Because the hardness of the injection molded TPU is mainly determined by the hard segment content in the TPU structure (the hard segment content refers to the mass percentage of the hard segment in the TPU), the hardness of the TPU can be increased along with the higher hard segment content. Therefore, the gradual change in the hardness of the outer skin layer 112 is achieved by gradually decreasing or increasing the hard segment content in the TPU resin material during the injection molding process.

Illustratively, the extruder used to process the granular TPU feed into a molten state may gradually add the TPU granules having a greater hard segment content to achieve a uniform increase in hardness of the injection molded outer skin layer 112. Or mixing two kinds of TPU with different hardness, and adjusting the hard segment content of the mixed TPU by gradually and uniformly adjusting the mixing ratio in the injection molding process. Alternatively, the outer skin layer 112 can be produced with a gradual change in hardness by gradually adding polyol to the TPU raw material during the injection molding process to gradually reduce the hard segment content.

Because of having similar components, the first resin strip 51 and the second resin strip 52 formed by injection molding have tighter joints, are not easy to fall off and break, improve the product yield in the process of producing the outer skin layer 112, and improve the structural stability of the insertion tube 11 having the outer skin layer 112 applied in various detection environments.

Fig. 2 shows only one exemplary embodiment, and the first resin strip 51 and the second resin strip 52 are not limited to the strip-shaped structure in fig. 2, but may have other forms and structures, see the detailed description below.

Referring to fig. 4, fig. 4 is a schematic structural view of an endoscope insertion tube 11 according to another embodiment. In one embodiment, the flexible pipe body 111 comprises a spiral pipe; the first resin strip 51 is spirally wound on the surface of the flexible pipe body 111 to form a plurality of spiral rings; the spiral direction of the first resin strip 51 is opposite to the spiral direction of the spiral pipe; the shape of the second resin strip 52 is adapted to the shape between at least two adjacent spiral rings among the plurality of spiral rings of the first resin strip 51.

In a specific embodiment, first resin strip 51 and second resin strip 52 are substantially equal in length, and each extend from the front end to the rear end of flexible tube 111.

The spiral direction of the spiral tube is understood to mean the direction of the spiral loop in the spiral tube. Taking the horizontal insertion tube 11 held by a person as an example, the spiral direction of the spiral tube goes around to the side where the person is, and the first resin strip 51 goes around to the side opposite to the human body.

In practical applications, the helical tube has a single helical direction, and when the insertion tube 11 is bent to a side away from the helical direction, bending stress is generated, making it difficult for an operator to control the insertion tube 11. Therefore, the present embodiment improves the handleability of the insertion tube 11 by making the spiral direction of the first resinous strip 51 opposite to the spiral direction of the spiral tube so that the bending stress of the first resinous strip 51 and the bending stress of the spiral tube at least partially cancel each other when the insertion tube 11 is bent; and the insertion tube 11 is beneficial to being restored to the initial shape after being bent, the deformation of the insertion tube 11 after being bent for many times is reduced, and the control accuracy of the insertion tube 11 is influenced.

In one embodiment, the width of the first resin strip 51 gradually increases from the front end toward the rear end; and/or the width of the second resin strip 52 gradually increases from the front end toward the rear end. Here, three schemes are included: the width of the first resin strip 51 is gradually increased, and the width of the second resin strip 52 is kept unchanged; the width of the second resin strip 52 gradually increases, and the width of the first resin strip 51 remains unchanged; the width of each of the first resin strip 51 and the second resin strip 52 is gradually increased.

The width of the resin strip refers to the width of the spiral ring formed by the resin strip, and the width of the spiral ring is the length of the spiral ring in the axial direction of the flexible pipe body 111. The direction represented by the broken line in fig. 4 is the width of the first resin strip 51.

For example, the wider the width of the first resin strip 51, the fewer its number of joints with the second resin strip 52, and thus the stiffer the corresponding skin layer 112 pipe section; the narrower the width of the first resin strip 51, the greater the number of joints with the second resin strip 52, and therefore the softer the corresponding skin layer 112. Therefore, the present embodiment adjusts the number of the joint lines of the first resin strip 51 and the second resin strip 52 by adjusting the width of the first resin strip 51 and/or the second resin strip 52, thereby adjusting the variation in the hardness of the outer skin layer 112.

In the following examples, examples of the method for processing the outer skin layer 112 of the insertion tube 11 of the present application will be described. This processing method can be realized based on the extrusion apparatus in the following examples.

In the following embodiments, first, an example of an extrusion apparatus for processing the outer skin layer 112 of the insertion tube 11 will be described. It should be understood that the present method of forming the outer skin 112 of the insertion tube 11 is not limited to this extrusion apparatus. The embodiment of the extrusion device is not intended to be limiting as to the construction and method of manufacture of the insert tube 11 of the present application.

In one embodiment, the extrusion apparatus includes a shaping channel 46, at least one feed channel; the forming passage 46 is used for the flexible pipe body 111 to be wrapped with the outer skin layer 112 to travel; when a plurality of feeding channels are arranged, the feeding ports of the feeding channels are correspondingly connected with a plurality of extruders so as to receive resin materials with various hardness; the outlets of the plurality of feed channels are sequentially arranged along the extending direction of the forming channel 46, and the outlets of the feed channels are communicated with the forming channel 46, so that the extruded resin material is coated on the outer surface of the flexible pipe body 111.

During the process of the flexible pipe body 111 advancing in the forming channel 46, the discharging sequence of the plurality of feeding channels is adjusted, so that the front end pipe section and the rear end pipe section of the outer skin layer 112 formed on the flexible pipe body 111 by injection molding are soft and hard.

In this embodiment, the resin material in a molten state is extruded by an extruder, and the resin material extruded by one extruder is injected into one feed passage. Generally, an extruder processes a solid injection molding material into a molten state by heating and extruding, and then extrudes the material to a corresponding feed channel at a specific extrusion pressure or extrusion speed. The resin material may be any of TPU (Thermoplastic polyurethane elastomer rubber), polyester, nylon, rubber, or silicone. In a specific embodiment, TPU is used for the plurality of resin materials.

Referring to fig. 5, fig. 5 is a cross-sectional view of an extrusion apparatus according to an example embodiment. In one example, the extrusion apparatus includes an inner die 41, an outer die 42, and at least one intermediate die 43; the intermediate die 43 includes a connected feed cylinder and an insert cover 432, the side wall of the insert cover 432 extending between the outer die 42 and the inner die 41 to form a feed channel with at least one of the outer die 42 or the inner die 41.

In this example, a first feeding passage 441 is formed between the side wall of the insertion cover 432 and the outer mold 42, and a second feeding passage 442 is formed between the side wall of the insertion cover 432 and the inner mold 41. The outer die 42 is provided with a first feeding cylinder 451 which is communicated with the first feeding channel 441; the feed cylinder of the intermediate die 43 is in communication with the second feed passage 442 as a second feed cylinder 452. The extrusion device in this example thus has two feed channels. It will be appreciated that more than two feed channels may be formed by providing the number of intermediate dies 43.

It should be noted that the outlets of the feeding channels may be independent from each other, the outlets of the feeding channels are sequentially arranged along the extending direction of the forming channel 46, and the distance between two adjacent outlets should be small. The outlets of the plurality of feed channels may be interconnected to collectively form a total outlet for extruding the resin material onto the flexible pipe body 111.

In another embodiment, it is also possible to provide that the extrusion apparatus further comprises a tractor provided at one side of the forming channel 46 for regulating the traveling speed of the flexible pipe body 111. For example, the tractor is used to control the traveling speed of the flexible pipe body 111 to be gradually changed in one direction to adjust the coating amount of the resin material on the flexible pipe body 111.

Specifically, two tractors may be provided, which are respectively used for dragging two ends of the flexible pipe 111, and the speeds of the two tractors should be kept consistent. Schematically. During the injection molding process, the flexible pipe body 111 travels within the molding passage 46.

According to an embodiment of the present application, the extrusion device further includes a centering mold, and the centering mold is used for penetrating through the flexible pipe body 111 and tightly fitting with the flexible pipe body 111.

According to an embodiment of the present application, the centering mold is an inflatable mold that is deflated to be removed from the flexible pipe body 111.

According to an embodiment of the present application, a surface of the centering mold is coated with a non-stick coating to repel the resin material.

Referring to fig. 6, fig. 6 is a flowchart illustrating a method of processing an outer skin layer 112 of an endoscope insertion tube 11 according to another embodiment. In one embodiment, a method of processing an outer skin layer 112 of an endoscope insertion tube 11 includes:

s61, during the running of the flexible pipe body 111, a first resin material is extruded on the surface of the flexible pipe body 111 to form the first resin strip 51, wherein the extrusion temperature of the first resin material is within 5 ℃ higher than the curing temperature of the first resin material.

S62, extruding a second resin material between the formed first resin strips 51 to form second resin strips 52, wherein the curing temperature of the second resin material is 40-60 ℃ lower than that of the first resin material, and the extruding temperature of the second resin material is 20-40 ℃ higher than that of the second resin material; wherein the hardness of the first resin strip 51 and/or the second resin strip 52 is gradually increased from the front end toward the rear end of the outer skin layer 112 so that the hardness of the insertion tube 11 is gradually increased.

In the present embodiment, the first resin strip 51 in the form of a strip may be extruded by the above-described extrusion device. At this time, the outlet of the feed passage is located at one side of the flexible pipe body 111, whereby the extruded resin material just falls on the surface of the flexible pipe body 111 to form the projected first resin strip 51.

First resin strip 51 and second resin strip 52 are injection molded in different processes. After the first resin strip 51 is injection-molded, the curing step of the first resin strip 51 is performed; after the second resin strip 52 is injection-molded, the second resin strip 52 is cured.

In the curing process, the temperature of the environment where the first resin strip 51/the second resin strip 52 are located may be adjusted to cure the first resin strip 51/the second resin strip 52. Alternatively, a curing box is provided in which the temperature is adjustable, and the first resin strip 51/second resin strip 52 are cured in the curing box. The first resin strip 51/second resin strip 52 may be solidified and cooled by a blower, water cooling, or the like.

In this embodiment, the extrusion temperature of the first resin material is within 5 ℃ higher than the curing temperature of the first resin material, so that the extrusion temperature of the first resin material is low, and the first resin material can be extruded onto the flexible pipe body 111 in a state of poor fluidity, so that the first resin material does not flow under the action of gravity when being placed on the flexible pipe body 111, and maintains a set shape.

In the embodiment, the extrusion temperature of the second resin material is set to be 20-40 ℃ higher than the curing temperature of the second resin material, so that the second resin material is extruded between the first resin strips 51 in a state of good fluidity, and the second resin material can flow between the first resin strips 51 and be fully and uniformly filled between the first resin strips 51, thereby avoiding the situations of uneven thickness, leak, unevenness and the like on the surface of the produced outer skin layer 112.

In addition, in the present embodiment, the curing temperature of the second resin material is 40 ℃ to 60 ℃ lower than the curing temperature of the first resin material, so that the curing speed of the second resin material is relatively slow, and the uniformity of the formed second resin strips 52 is realized.

Through the setting of the extrusion temperature difference and the curing temperature difference of the first resin material and the second resin material, when the second resin material is extruded, the first resin strip 51 can not be melted, so that the forming effect of the outer skin layer 112 is ensured.

In one embodiment, extruding a first resin material on a surface of the flexible pipe body 111 to form a first resin strip 51 includes:

during the travel of the flexible pipe body 111, the flexible pipe body 111 is controlled to rotate axially along itself to injection-extrude the first resin strip 51 in a spiral shape.

The rotation direction of the flexible pipe body 111 is opposite to the spiral direction of the spiral pipe in the flexible pipe body 111.

Here, the flexible pipe body 111 can be pulled by the retractor to make a circular motion in its own axial direction while making a linear motion. While keeping the outlet of the feed channel stationary, the extruded first resin strip 51 is thus helical.

Thereafter, the resin material is further injected between the first resin strips 51 by a worker or in a manner of extrusion still using an extruder to form the second resin strips 52. It should be understood that when the resin material is extruded by the extruder, the second resin strip 52 can be processed at a time by adjusting the shape and size of the extrusion port of the feeding passage while drawing the flexible pipe body 111 in cooperation with the tractor while making the linear movement and the circular movement along its own axis.

In one embodiment, after the first resin stripes 51 are formed, a cooling process step is added in which the cooling rate is more than 0.5 ℃ per second.

After the first resin strip 51 is subjected to the curing process, the cooling process is performed to further cure the shape of the first resin strip 51. In the cooling step, the solidified first resin strip 51 may be cooled by natural air cooling, forced air cooling, water cooling, ice water bath, or the like to further solidify the shape of the first resin strip 51, thereby preventing the outer skin layer 112 from deforming during subsequent use.

By setting the cooling speed to be more than 0.5 ℃ per second, the cooling efficiency can be improved and the production period can be shortened. On the other hand, the deformation of the outer skin layer 112 caused by too fast cooling is avoided, and the yield is not influenced.

In one embodiment, the flexible pipe body 111 may be rotationally cooled after the second resin strip 52 is injection molded. By cooling the flexible pipe body 111 by rotating it axially along the flexible pipe body 111, the second resin material is filled more uniformly along the spiral gaps of the first resin strips 51, and the cooling uniformity of the surface of the outer skin layer 112 is improved.

Referring to fig. 7, fig. 7 is a schematic structural view of a belt extrusion device and an annular scraper according to an embodiment. In one embodiment, after the second resin strip 52 is formed, the outer skin layer 112 is surface-smoothed by an annular doctor blade.

In fig. 7, the scraping mold 61 includes a base and an annular scraper disposed on the base, the flexible pipe 111 covers the outer skin layer 112 and then passes through the annular scraper, and the annular scraper is used for smoothing uneven portions of the surface of the outer skin layer 112.

Because the resin material is coated on the flexible pipe body 111, the outer skin layer 112 still has a certain plasticity, when the flexible pipe body 111 passes through the annular scraper, the protrusion on the outer skin layer 112 is smoothed, and the smoothed resin material is used for filling the concave part on the outer skin layer 112, so that the surface of the outer skin layer 112 is smooth.

In one embodiment, the angle between the wall of the annular scraper and the direction of extension of the forming channel 46 is 30 ° to 60 °. The outer skin layer 112 with the uneven surface of the flexible pipe body 111 can be effectively leveled at a smaller included angle, abrasion to the edge of the annular scraper is reduced, and the annular scraper can still keep a better scraping effect under long-time work. Moreover, the scraped resin material is accumulated on the blade wall of the annular scraper, so the scraped resin material can slide down along the inclined blade wall to be filled in the pits on the outer skin layer 112, and the smoothing effect on the outer skin layer 112 is improved. The roughness of the outer skin layer 112 was below 1 micron after treatment with an annular doctor blade.

In the following embodiments, the resin strips are collectively referred to as a first resin strip 51 and a second resin strip 52, and the description of the resin strips applies to the first resin strip 51 and the second resin strip 52.

Specifically, in one embodiment, the hardness of the first resin strip 51 and/or the second resin strip 52 is gradually increased from the front end toward the rear end of the outer skin layer 112, so that the hardness of the insertion tube 11 is gradually increased, including:

a plurality of resin materials with different hardness are correspondingly injected into a plurality of feed channels of the extrusion device.

In the process of injection molding to form first resin strip 51 and/or second resin strip 52, a plurality of resin materials are sequentially extruded in order of hardness from small to large, so that first resin strip 51 and/or second resin strip 52 is formed to have a plurality of hardness segments.

This can be understood here with reference to the structural embodiments of the extrusion device described above. Here, "sequentially extruding a plurality of resin materials" is achieved by regulating the discharge order of a plurality of feed channels. The discharge sequence of the feed channels can be controlled in a number of ways. In one embodiment, the discharge sequence can be adjusted by controlling the working sequence of the extruders correspondingly connected to the feed channels. When the extruder worked, feed channel ejection of compact to flexible body 111, when the extruder stop work, feed channel stopped the ejection of compact to flexible body 111 gradually.

In another embodiment, an on-off control valve may be provided at the feed cylinder to control the amount and rate of resin material flow into the feed channel. Therefore, the discharging sequence of the feeding channel is controlled by controlling the on-off control valves of all the feeding cylinders.

In yet another embodiment, an on-off control valve may be provided at the outlet of the feed channel to control the amount and rate of resin material flowing out of the outlet of the feed channel. Therefore, the discharging sequence of the feeding channels is controlled by controlling the on-off control valves of the outlets of all the feeding channels.

It should be understood that the control of the discharge sequence of the feed channels is not limited to these three ways here.

In this embodiment, although the resin strip includes a plurality of different hardness segments, since the resin strip is provided in plurality, the joint between two adjacent hardness segments does not cover a complete circumferential turn of the flexible pipe body 111 for each resin strip. Therefore, the stress at the time of bending the insertion tube 11 is decomposed by the plurality of first resin strips 51 and the plurality of second resin strips 52, thereby reducing the risk of breakage.

Here, the plurality of resin materials may be different in type and different in hardness, or may be the same in type but have different hardness by changing the composition. In one embodiment, the first resin strip 51 and the second resin strip 52 are TPU (Thermoplastic polyurethane elastomers) strips. The hardness of the TPU is adjusted by gradually changing the contents of the hard segment and the soft segment in the TPU during the injection molding process, so that the hardness of the first resin strip 51 and/or the second resin strip 52 formed by injection molding is gradually increased.

In another embodiment, the mixing area 47 may be provided to mix at least two resin materials having different hardness, and the mixing ratio of the two resin materials is continuously increased to gradually increase the hardness of the first resin strip 51 and/or the second resin strip 52 formed by injection molding.

Specifically, in a further embodiment, the hardness of the first resin strip 51 and/or the second resin strip 52 is gradually increased from the front end toward the rear end of the outer skin layer 112 so that the hardness of the insertion tube 11 is gradually increased, including:

The hardness of the mixed resin material is adjusted by mixing at least two resin materials during the travel of the flexible pipe body 111.

The mixed resin material is extruded to the surface of the flexible pipe body 111 to form the first resin strip 51 and/or the second resin strip 52.

Fig. 8 is a cross-sectional view of an extrusion apparatus with a compounding zone 47, according to an embodiment. The extrusion apparatus further comprises a compounding zone 47. The mixing area 47 is communicated with the extrusion ports of the multiple feeding channels and is communicated with the forming channel 46, and the multiple feeding channels enter the mixing area 47 to be mixed and then enter the forming channel 46; a mixing member is provided in the mixing area 47 to uniformly mix the resin materials of at least two hardnesses.

As will be understood based on the structure of the molding unit 40, the end of the insertion cover 432 of the middle mold 43 away from the feeding cylinder may be provided with a gap from the molding passage 46, so that a material mixing zone 47 is formed between the insertion cover 432, the outer mold 42 and the inner mold 41. Therefore, the resin material flowing out of the outlet of each feed channel flows to the mixing zone 47 in an omnidirectional direction of 360 °. The resin material is mixed by the mixing area 47 and then flows to the forming channel 46 gradually, and the surface of the flexible pipe body 111 in the forming channel 46 is coated with the resin material.

For the resin material used for forming the outer skin layer 112 of the endoscope insertion tube 11, the resin material in a molten state is viscous, and the hardness of the resin material entering from each feeding channel is different, so that after entering the mixing area 47, the mixing degree of various resin materials is low, and the resin material which is not uniformly mixed is injected on the surface of the outer skin layer 112, so that the hardness and the strength of the same cross section of the outer skin layer 112 are different, thereby influencing the transmission of torque and the flexibility of the front end tube section 31, and further bringing trouble to an operator using the endoscope.

Therefore, in the present embodiment, a mixing member is provided in the mixing area 47 to promote mixing of a plurality of resin materials and improve uniformity of mixing of the respective resin materials.

In an embodiment, the material mixing part is a turbulent flow structure 481 disposed in the material mixing area 47, and an extending direction of the turbulent flow structure 481 forms an included angle with a flowing direction of the resin material flowing through the turbulent flow structure 481.

Further, in order to improve the turbulent flow effect, a plurality of turbulent flow structures 481 may be disposed on both the surface of the outer mold 42 and the surface of the inner mold 41.

In one embodiment, the spoiler structure 481 is in the shape of an arc plate. The arc-shaped turbulent flow structure 481 has certain guidance for the resin material, and can change the flow direction of the resin material flowing through the turbulent flow structure 481 to a greater extent, so that turbulent flow is formed between the resin materials, and the degree of mixing between the resin materials is promoted.

Fig. 9 is a cross-sectional view of an extrusion apparatus with a compounding zone 47 according to another embodiment. In another embodiment with respect to the mixing member, the extrusion device includes a mixing bowl 471, a plurality of feed guides 4771 disposed on the mixing bowl 471, and a mixing tube disposed on the underside of the mixing bowl 471; a mixing region 47 is formed in the mixing bin 471, a feeding channel is formed in the feeding guide structure 4771, and a mixed flow channel 472 is formed in the mixed flow pipe. The heat-insulating layer 49 is wrapped outside the mixed flow channel 472 and the mixing bin 471.

The mixing member is a stirring structure 482 arranged in the mixing area 47, and the stirring structure 482 rotates and mixes resin materials with various hardness in the mixing area 47; the extrusion device further comprises a flow mixing channel 472 communicating with the outlet of the mixing silo 471, the outlet of the flow mixing channel 472 communicating with the shaping channel 46.

In this embodiment, the stirring structure 482 may include a stirring rod having a propeller structure thereon to stir-mix the plurality of resin materials in the mixing zone 47. The stirring structure 482 may be configured with a driving member, such as a motor, a cylinder, etc., to drive the stirring rod to rotate and control the rotation speed of the stirring rod, so as to adaptively adjust the rotation speed of the stirring rod according to the amount of the resin material and the type of the resin material in the material mixing area 47, thereby improving the uniformity of material mixing.

Also, in this embodiment, the stirring structure 482 performs primary mixing, and the mixing channel 472 performs secondary mixing. The mixing channel 472 is elongated. In one aspect, the elongated configuration of the mixing channel 472 can further promote mixing between the resin materials. On the other hand, the resin material speed after stirring structure 482 mixes is very fast, and mixed flow channel 472 can adjust resin material's speed and pressure, and the speed is very fast when avoiding the cladding of resin material on flexible pipe body 111, and produces the ripple, influences the quality of moulding plastics.

In one embodiment, the mixing channel 472 is curved, and the resin material moves in a curve in the mixing channel 472. Specifically, the mixing channel 472 is helical. The helical structure can improve the material mixing effect with the flow distance of the extension resin material of the great degree of less volume.

The export of mixed flow pipe can be connected to a mould, has the water conservancy diversion passageway that is the tube-shape in this mould, and this water conservancy diversion passageway extends along left right direction, and the right side narrows down gradually, and the right-hand member portion of water conservancy diversion passageway is uncovered, and communicates with shaping passageway 46, and the resin material that consequently the export of water conservancy diversion passageway flows out is at the periphery wall of flexible body 111 with 360 omnidirectional cladding. As the flexible pipe body 111 travels within the molding passage 46, the resin material flowing out of the annular mouth of the feed passage coats the entire outer peripheral surface of the flexible pipe body 111.

In the above embodiment, the extrusion unit is plural. In the following examples, one extrusion unit is exemplified.

According to an embodiment of the present application, the first resin strip 51 and the second resin strip 52 are combined to form the outer skin layer 112, and the hardness of the front end pipe section and the hardness of the rear end pipe section of the formed outer skin layer 112 are relatively soft and relatively large because the hardness of the first resin strip 51 and/or the second resin strip 52 is gradually increased from the front end to the rear end of the outer skin layer 112. The harder rear end tube section is beneficial to transmitting torque to the front end tube section, and improves the controllability of the insertion tube 11. The softer front end pipe section is beneficial to flexible bending in the detected body.

And, the outer skin layer 112 is formed in a variable softness by a plurality of different resin materials by the sectional injection molding in comparison with the direction toward the rear end along the front end of the flexible pipe body 111. The junction between the two sections extends radially of the flexible pipe body 111. However, when the insertion tube 11 is operated with the outer skin 112 bent in the axial direction, the circumferentially distributed joints are subjected to large stresses, which may lead to a risk of breakage of the outer skin 112. In the present application, the first resin strip 51 and the second resin strip 52 both extend in the axial direction of the flexible pipe body 111, so that the outer skin layer 112 is formed to have good hardness continuity and structural stability in the axial direction. The smoothness and smoothness of the trajectory and the structural stability of the flexible pipe body 111 when bent in the axial direction are improved. The risk of the insertion tube 11 running away due to the outer sheath 112 breaking in the radial direction when the insertion tube 11 is bent is effectively prevented.

In conclusion, the technical scheme of the application improves the controllability and the moving flexibility of the insertion tube 11 and improves the controlled stability of the insertion tube 11.

While the present application has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present application may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

1. An insertion tube for an endoscope, comprising:

a flexible pipe body comprising a spiral pipe;

the outer skin layer is wrapped outside the flexible pipe body and is provided with a rear end close to the endoscope operation part and a front end close to the endoscope bending part; the outer skin layer comprises a first resin strip and a second resin strip, the first resin strip is spirally wound on the surface of the flexible pipe body, and the spiral direction of the first resin strip is opposite to that of the spiral pipe, so that when the insertion pipe is bent, the bending stress of the first resin strip and the bending stress of the spiral pipe are at least partially offset; the second resin strip is filled in the spiral gap of the first resin strip;

the first and second resin strips each extend from the front end to the rear end;

the hardness of the first resin strip is gradually increased and/or the hardness of the second resin strip is gradually increased from the front end to the rear end, so that the hardness of the insertion tube is gradually increased.

2. The insertion tube of an endoscope according to claim 1, wherein said first resin strip is gradually increased in width from said front end toward said rear end; and/or

From the front end to the rear end direction, the width of second resin strip increases gradually.

3. The insertion tube of an endoscope according to claim 1, wherein said first resin strip includes a plurality of first hardness sections, which are arranged in order of hardness from smaller to larger in a direction from said front end toward said rear end; and/or

The second resin strip comprises a plurality of second hardness sections, and the second hardness sections are sequentially arranged from the front end to the rear end according to the sequence of hardness from small to large.

4. The insertion tube of an endoscope according to claim 1, wherein said first resin strip and said second resin strip each comprise a thermoplastic polyurethane elastomer rubber.

5. A method for machining an outer skin layer of an insertion tube of an endoscope, comprising:

controlling the flexible pipe body to rotate along the axial direction of the flexible pipe body in the advancing process of the flexible pipe body, extruding a first resin material on the surface of the flexible pipe body, and performing injection molding to form a spiral first resin strip from the front end to the rear end of the flexible pipe body; wherein a rotation direction of the flexible pipe body is opposite to a spiral direction of a spiral pipe inside the flexible pipe body, so that when the insertion pipe is bent, a bending stress of the first resin strip and a bending stress of the spiral pipe are at least partially offset; the extrusion temperature of the first resin material is within 5 ℃ higher than the curing temperature of the first resin material;

6. The method of claim 5, wherein a cooling process step is added after forming said first resin strips, wherein a cooling rate is greater than 0.5 ℃ per second.

7. The method of claim 5, wherein after forming said second resin strip, said flexible pipe body is rotary cooled.

8. The method of claim 5, wherein after forming said second resin strip, the surface of said outer skin layer is smoothed by an annular doctor blade.