CN113478796B

CN113478796B - Medical cannula pointed end forming device

Info

Publication number: CN113478796B
Application number: CN202110739210.2A
Authority: CN
Inventors: 黄汉东
Original assignee: Changzhou Longlaifu Medical Material Co ltd
Current assignee: Changzhou Longlaifu Medical Material Co ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2023-08-08
Anticipated expiration: 2041-06-30
Also published as: CN113478796A

Abstract

The invention discloses a medical cannula tip forming device which comprises a supporting piece, a tip forming component and a heating component. The supporting piece is movably arranged in the tip forming assembly in a penetrating mode, a cavity is formed by the outer surface of the supporting piece and the inner surface of the tip forming assembly, the cavity is provided with a preset tip shape, and the tip forming assembly is provided with a thermal resistance piece used for controlling heat distribution of the cavity. The heating component is connected with the tip forming component and is used for heating the tip of the medical catheter to be formed in the cavity so as to form the tip of the medical cannula to be formed. According to the invention, the tip of the medical cannula is extruded to the cavity formed by the tip forming assembly and the supporting piece, when the heating assembly heats the cavity, the heat resistance piece can control the heat distribution of the cavity, and the tip can replicate the preset tip shape in the cavity after melting, so that the shape and the size of the tip of the cannula meeting high requirements are formed, the performance of the cannula in the process of penetrating into a blood vessel is ensured, and the rigidity of the part beyond the tip is ensured.

Description

Medical cannula pointed end forming device

Technical Field

The invention relates to the technical field of medical instruments, in particular to a medical cannula tip forming device.

Background

The extracorporeal circulation cannula is one kind of important medical plastic pipeline, and during extracorporeal circulation operation, the extracorporeal circulation cannula needs to be connected to the blood vessel to form blood flow channel. The tip will be inserted into the blood vessel of the human body and the geometry and some mechanical properties of the tip will have a direct impact on the efficiency and quality of the connection procedure, and the effect of the blood flow path after connection. In minimally invasive cardiac surgery, which has been rapidly widespread in recent years, the most common circulatory cannulas have placed higher demands.

In minimally invasive cardiac surgery, the surgeon first pierces the skin with a piercing needle up to the target vessel, enlarges the pierced hole in the epidermis to a certain extent with a small knife, then sends a metal spring guide wire through the channel formed by the piercing needle into the target vessel, and then sequentially expands the channel around the guide wire under the guidance of the guide wire with a series of progressively larger expansion tubes. After the dilation procedure is completed, the extracorporeal circulation cannula with plastic tube core is used to insert into the blood vessel. Because human tissue, including skin, muscle, etc., has excellent elasticity, the passageway still generates a large contractive force after the dilation tube is expanded. In the process of inserting the extracorporeal circulation cannula into a blood vessel along a guide wire through tissues such as skin, muscle and the like, under the wrapping of the human tissues, the advancing resistance generated by the wall thickness of the cannula and the friction force formed between the wall of the cannula and the human tissues need to be overcome in the advancing process of the cannula.

It can be seen that the shape and mechanical properties of the cannula tip are directly related to the resistance created by the penetration process. In order to make the resistance as small as possible, and at the same time, under a certain resistance, the cannula wall has enough strength, and the conditions of wrinkling, bending and the like do not occur, the cannula tip needs to meet the following requirements:

(1) The cannula tip profile is approximately conical with a smooth transition.

(2) The cannula tip is in close proximity to the die. When the cannula and the hub are inserted into biological tissue simultaneously, if there is a large gap between the cannula tip hub, this gap will create a significant resistance to advancement.

(3) The cannula tip has enough strength, and keeps the conical surface shape without wrinkling under the condition of penetration resistance.

In the prior art, the tube body of the extracorporeal circulation cannula is usually formed by an impregnation process, the tube body formed by the impregnation process has uniform tube wall thickness, but the tube tip shape meeting the requirements cannot be formed, and the resistance is difficult to reduce.

Disclosure of Invention

The purpose of the invention is that: the medical cannula tip forming device is provided, the medical cannula tip is extruded to a cavity of the forming device, the shape of the cannula tip in the cavity can be copied, and the shape and the size of the cannula tip meeting high requirements are formed, so that the performance of the cannula in the process of penetrating into a blood vessel is ensured.

In order to achieve the above object, the present invention provides a medical cannula tip forming device, comprising: a support, a tip forming assembly, and a heat generating assembly.

The supporting piece is movably arranged in the tip forming assembly in a penetrating mode, a cavity is formed by the outer surface of the supporting piece and the inner surface of the tip forming assembly, the cavity is in a preset tip shape, a thermal resistance piece is arranged on the tip forming assembly, and the thermal resistance piece is used for controlling heat distribution of the cavity. The heating component is connected with the tip forming component and is used for heating the tip of the medical cannula to be formed in the cavity so as to form the tip of the medical cannula to be formed.

In one embodiment, the tip forming assembly includes a thermally conductive member and a heat capacity member;

the heat conducting piece and the heat containing piece are connected with each other and are all arranged on the supporting piece in a penetrating mode, the heating component is arranged on the heat conducting piece, so that the heat conducting piece forms a heating area, the inner surface of the heat conducting piece and the outer surface of the supporting piece jointly form the cavity, the heat containing piece is connected with the heat conducting piece and forms a heat limiting area, and the heat resistance piece is arranged between the heating area and the heat limiting area.

In one embodiment, the thermal resistance member includes a thermal resistance groove, and the thermal resistance groove is formed between the heat conduction member and the heat capacity member; the supporting piece is provided with a supporting inner hole, and the outer diameter of the supporting piece is smaller than the inner diameter of the medical cannula to be formed.

In a certain embodiment, the inner surface of the heat container comprises a guiding surface and a transition surface which are sequentially connected, the inner surface of the heat conducting piece comprises a reinforcing surface, a sharp conical surface and a positioning surface which are sequentially connected, and the transition surface is connected with the reinforcing surface;

the guide surface is used for guiding the medical cannula to be formed to penetrate through the heat conducting piece and the heat containing piece, the positioning surface is used for positioning the tip end of the medical cannula to be formed in the heating area, and the tip conical surface, the reinforcing surface, the transition surface and the outer surface of the supporting piece jointly form a cavity surface of the cavity.

In a certain embodiment, an angle formed by the pointed cone surface and the outer surface of the supporting piece is 50-60 degrees, and an angle formed by the reinforcing surface and the outer surface of the supporting piece is 11-15 degrees.

In one embodiment, the tip forming assembly further includes a positioning member coupled to the heat receptacle.

In one embodiment, the heat generating component comprises a mounting member, a heat generating member and a temperature sensing member;

the mounting piece is used for being sleeved on the supporting piece and connected with the tip forming assembly, the heating piece and the temperature sensing piece are both arranged on the mounting piece, and the heating piece is in heat conduction connection with the temperature sensing piece.

In one embodiment, the heating element comprises a high frequency heating ring, the temperature sensing element comprises a thermistor wire, the high frequency heating ring and the thermistor wire are wound on the outer surface of the mounting element, and the thermistor wire is arranged close to the high frequency heating ring.

In one embodiment, the heat generating component further comprises a heat insulating member disposed between the high frequency heating coil and the mounting member.

In one embodiment, the mounting is made of silicon steel.

Compared with the prior art, the medical cannula tip forming device provided by the embodiment of the invention has the beneficial effects that:

through the die cavity extrusion that forms together sharp pointed end towards sharp point forming module and support piece of medical intubate, when heating element heats the die cavity, thermal resistance spare can control the heat distribution of die cavity, can duplicate the interior preset sharp pointed end shape of die cavity after the sharp point melts, forms intubate sharp pointed end shape and the size that satisfies high requirement to ensure the performance of intubate puncture into the blood vessel in-process, and the part outside the sharp point then keeps great rigidity, ensures to conduct the extrusion force of outside to sharp point, realizes the extrusion to sharp point.

Drawings

In order to more clearly illustrate the technical solutions of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic perspective view of a medical cannula tip forming device according to an embodiment of the present invention;

FIG. 2 is a schematic side view of a medical cannula tip forming device according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a medical cannula tip forming device according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a tip forming assembly according to one embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of a tip forming assembly according to one embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of a medical cannula tip forming device according to an embodiment of the present invention;

FIG. 7 is an enlarged schematic view of the portion VII of the embodiment of FIG. 3;

FIG. 8 is a schematic view of the cross-sectional configuration of the tip of the medical cannula after molding according to the present invention;

fig. 9 is an enlarged schematic view of part ix in the embodiment of fig. 3.

Main elements and symbol description:

100. a medical cannula tip forming device; 10. a support; 11. a support bore; 12. supporting the outer wall; 13. a cohesion surface; 20. a tip forming assembly; 21. a heat conductive member; 211. a reinforcing surface; 212. a sharp conical surface; 213. a positioning surface; 214. positioning an inner hole; 22. a heat capacity; 221. a guide surface; 222. a transition surface; 223. a gap; 23. a heat resistance member; 231. a thermal resistance groove; 24. a positioning piece; 30. a heating component; 31. a mounting member; 32. a heat generating member; 321. a high frequency heating ring; 33. a temperature sensing member; 331. a thermistor wire; 34. a heat insulating member; 40. a cavity; 200. a medical cannula; 201. a tip; 202. the inner wall of the medical cannula; 203. a hot melt zone; 204. and a high temperature deformation zone.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be understood that the step numbers used herein are for convenience of description only and are not limiting as to the order in which the steps are performed.

It is to be understood that the terminology used in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The terms "comprises" and "comprising" indicate the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The term "and/or" refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

Referring to fig. 1 to 4, an embodiment of the present invention provides a medical cannula tip forming device 100, including: a support 10, a tip forming assembly 20, and a heat generating assembly 30.

The supporting member 10 movably penetrates through the tip forming assembly 20, a cavity 40 is formed by the outer surface of the supporting member 10 and the inner surface of the tip forming assembly 20, the cavity 40 has a preset tip shape, a thermal resistance member 23 is arranged on the tip forming assembly 20, and the thermal resistance member 23 is used for controlling heat distribution of the cavity 40. The heat generating assembly 30 is connected to the tip forming assembly 20 and is used to heat the tip 201 of the medical cannula 200 to be formed in the cavity 40 to form the tip 201 of the medical cannula 200 to be formed.

In this embodiment, the support member 10 is used to be inserted into the medical cannula 200 to be formed, and supports the inner wall 202 (as shown in fig. 7) of the medical cannula, so as to prevent the inner wall 202 of the medical cannula from being deformed during the forming process.

The tip forming assembly 20 is the primary element that affects the quality of the formation of the tip 201, and serves to transfer heat and shape the tip 201 throughout the medical cannula tip forming device 100. Specifically, the tip forming assembly 20 is provided with a forming through hole, and when the tip forming assembly 20 is sleeved on the support member 10, the outer surface of the support member 10 and the inner surface of the tip forming assembly 20 together form the cavity 40. Wherein the cavity 40 has a predetermined tip shape that is approximately conical, transitions smoothly, and meets the desired cannula tip shape and size to ensure performance during penetration of the medical cannula into the blood vessel.

The heat generating component 30 can generate an adjustable preset temperature, for example, a temperature range of 80-220 ℃. The heating component 30 is connected with the tip forming component 20, when the heating component 30 generates heat, the heat can be conducted to the cavity 40 of the tip forming component 20, so that the tip 201 of the medical cannula 200 to be formed in the cavity 40 is heated, the tip 201 is melted, and the tip 201 can accurately replicate the preset tip shape of the cavity surface of the cavity 40.

In the actual use process, the medical cannula 200 to be molded is sleeved on the supporting piece 10, then the supporting piece 10 penetrated with the medical cannula 200 passes through the molding through hole of the tip molding assembly 20, so that the tip 201 of the medical cannula 200 to be molded enters the cavity 40, when the heating assembly 30 heats the cavity 40, the tip 201 of the medical cannula 200 positioned in the cavity 40 is heated and melted to fill the cavity 40, and after heating and cooling are stopped, the tip 201 of the medical cannula 200 replicates the preset tip shape in the cavity 40.

Referring to fig. 1 and 2, in a certain embodiment, the outer surface of the supporting member 10 is a cylindrical surface, and the inner wall 202 of the medical cannula is attached to the outer surface of the supporting member 10 in the forming process, so that the inner wall 202 of the medical cannula is ensured to be always kept as the cylindrical surface and not deformed, so that the formed medical cannula 200 can be attached to the plastic tube core, and the puncture resistance is effectively reduced.

In one embodiment, the support 10 is provided with a support bore 11 and the support 10 has an outer diameter smaller than the inner diameter of the medical cannula 200 to be formed.

In this embodiment, the supporting member 10 is a thin-walled circular tube with a supporting inner hole 11, so that heat transfer in the axial direction can be reduced. In addition, the outer diameter of the supporting piece 10 is smaller than the inner diameter of the medical cannula 200 to be formed, so that the inner diameter of the medical cannula 200 in the forming section is smaller than the inner diameter before forming, and the tube core is tightly held.

In one particular embodiment, the support 10 comprises a steel core that is capable of sliding within the molding bore of the tip molding assembly 20 to either introduce the medical cannula 200 to be molded into the cavity 40 or remove the molded medical cannula 200 from the cavity 40.

In other embodiments, the support member 10 may be other components, which are not specifically limited herein.

During the molding process, different portions of the medical cannula 200 to be molded require different amounts of heat. The tip 201 of the medical cannula 200 needs to be melted in order to be shaped to exactly replicate the shape of the cavity 40, while the parts other than the tip 201 need to be kept at a low temperature in order to avoid unwanted deformation. In addition, since the precise molding of the tip 201 also requires an external pressing force, the pressing force is transmitted to the tip 201 when the external pressing force acts on a portion other than the tip 201. Since the material of the medical cannula 200 is in a glassy or highly elastic state to effectively provide the compressive force, the portions other than the tip 201 are maintained at a low temperature.

To solve the above problems, the thermal resistive member 23 of the tip forming assembly 20 of the present invention can control the heat distribution, ensuring that the tip 201 (i.e., deformed section) of the medical cannula 200 is at a melting temperature, and that the portion (i.e., undeformed section) of the medical cannula 200 other than the tip 201 is lower than the melting temperature of the plastic component of the medical cannula 200.

In summary, in the medical cannula tip forming device 100 according to the embodiment of the present invention, the tip forming component 20 and the supporting member 10 together form the cavity 40 with a preset tip shape, when the heating component 30 heats the cavity 40, the thermal resistance member 23 can control the heat distribution of the cavity 40, and after the tip 201 of the medical cannula 200 disposed in the cavity 40 melts, the preset tip shape in the cavity 40 can be replicated to form the cannula tip shape and size meeting high requirements, so that the performance of the cannula in the process of penetrating into a blood vessel is ensured, while the part other than the tip 201 maintains a larger rigidity, so that the external extrusion force can be transmitted to the tip 201, and the extrusion of the tip 201 is realized.

Further, to achieve different temperatures in different areas of the tip forming assembly 20, the relationship between the temperature of the heat generating area of the tip forming assembly 20, the heat conduction in different areas of the tip forming assembly 20, the dissipation speed of the heat to the surrounding environment, and the heat conduction and the temperature rise needs to be considered:

when the heat generating component 30 is in operation, a large amount of heat is generated by the tip forming component 20 near the heat generating component 30, and after the temperature is rapidly increased, the heat is conducted inside the tip forming component 20 at a much higher speed than dissipated to the surrounding environment. Therefore, the heat generating component 30 should be installed close to the region of the tip forming component 20 where the high temperature is required, and the heat conduction between the region of the tip forming component 20 where the high temperature is required (hereinafter, heat generating region) and the region where the high temperature is not required (hereinafter, heat limiting region) should be reduced as much as possible.

Referring specifically to fig. 3 and 4, in one embodiment, the tip forming assembly 20 includes a thermally conductive member 21 and a heat receiving member 22. The heat conducting member 21 and the heat receiving member 22 are connected to each other and are all penetratingly provided on the supporting member 10, the heat generating assembly 30 is provided on the heat conducting member 21 such that the heat conducting member 21 forms a heat generating region, the inner surface of the heat conducting member 21 and the outer surface of the supporting member 10 together form a cavity 40, the heat receiving member 22 is connected to the heat conducting member 21 and forms a heat limiting region, and the heat resistive member 23 is provided between the heat generating region and the heat limiting region.

In this embodiment, the tip forming assembly 20 includes two parts, one part being a heat conducting member 21 and the other part being a heat receiving member 22.

The heat conducting member 21 can efficiently conduct heat generated by the heat generating component 30 into the cavity 40, so that the tip 201 of the medical cannula 200 in the heat generating region can quickly reach the melting temperature, and the heat receiving member 22 can efficiently radiate heat, so that the actual temperature of the part except the tip 201 in the heat limiting region is lower than the melting temperature of the plastic component of the medical cannula 200. Meanwhile, by providing the thermal resistance groove 231 between the heat conducting member 21 and the heat receiving member 22, a temperature interval region is formed between the heat generating region and the heat limiting region, so that the efficiency of heat conduction from the heat conducting member 21 to the heat receiving member 22 can be effectively reduced.

In one embodiment, the heat conductive member 21 is made of a material having a high heat conductivity coefficient, such as a metal of copper, silver, aluminum, or the like.

In one embodiment, the heat capacity 22 is made of a material having a high specific heat capacity.

In one embodiment, the heat capacity 22 comprises a heat capacity block having a volume greater than that of the heat conductive member 21.

The heat capacity block can further reduce the temperature possibly increased by the heat limiting area, the heat capacity block is relatively large in volume, and a large amount of heat is required to be absorbed per one-degree-celsius temperature, so that the temperature increase near the heat capacity block is effectively prevented.

Referring to fig. 3 and 4, in one embodiment, the thermal resistive member 23 further includes a thermal resistive slot 231, and the thermal resistive slot 231 is disposed between the heat conducting member 21 and the heat receiving member 22.

In one embodiment, the thermal resistance slot 231 is a circular groove with a cross-sectional width of one millimeter.

Referring to fig. 5 and 6, fig. 5 and 6 are respectively a comparison of temperature field distribution when the temperature of the heating element 30 is constant at 150 degrees celsius and the thermal resistance groove 231 is provided and when the thermal resistance groove 231 is not provided.

As can be seen from the temperature distribution of the heat-resistant groove 231 shown in fig. 5, the temperature of the heat-generating area of the heat conducting member 21 on the right side in fig. 5 is 139-150 degrees celsius, the temperature of the heat-limiting area of the heat-receiving member 22 on the left side is less than 62.7 degrees celsius, and the middle is obviously divided.

As can be seen from the temperature distribution of fig. 6 without the thermal resistance groove 231, the temperature of the heating area of the right heat conducting member 21 in fig. 6 is 139 to 150 degrees celsius, the temperature of the heat limiting area of the left heat receiving member 22 is 95 to 106 degrees celsius, and the middle division is not obvious.

In this way, the temperature of different areas of the tip forming assembly 20 is different by the temperature interval of the thermal resistance groove 231, and the temperature distribution can improve the yield and efficiency of the tip forming process and reduce the probability of yellowing, embrittlement and cracking of the tip 201 of the plastic medical cannula 200.

In other embodiments, the resistive member 23 may also be formed from other annular components of high resistance materials, such as fiberglass, silicate, and the like.

Referring to fig. 4 and 7, in one embodiment, the inner surface of the heat container 22 includes a guiding surface 221 and a transition surface 222 connected in sequence, and the inner surface of the heat conducting member 21 includes a reinforcing surface 211, a conical surface 212 and a positioning surface 213 connected in sequence, and the transition surface 222 is connected with the reinforcing surface 211.

The guiding surface 221 is used for guiding the medical cannula 200 to be formed to penetrate through the heat conducting member 21 and the heat receiving member 22, the positioning surface 213 is used for positioning the tip 201 of the medical cannula 200 to be formed in the heating area, and the tip conical surface 212, the reinforcing surface 211, the transition surface 222 and the outer surface of the support member 10 together form a cavity surface of the cavity 40.

As shown in fig. 8, the tip 201 of the medical cannula 200 is also comprised of a cannula taper, a cannula reinforcing surface, and a cannula transition surface for connecting the cannula reinforcing surface to the undeformed section of the medical cannula 200. During the molding process, both the cannula taper surface and the cannula reinforcing surface of the tip 201 are located in the hot melt zone 203 of the medical cannula 200, and the cannula transition surface is located in the high temperature deformation zone 204 of the medical cannula 200.

Specifically, the cannula taper and cannula reinforcement of the tip 201 are located in the hot melt zone 203, and are formed by melting the tip 201 and then replicating the reinforcement 211 and taper 212 of the cavity 40, respectively. The transition surface of the cannula of the tip 201 is located in the high temperature deformation zone 204 and is formed by the melting of the tip 201 and the replication of the transition surface 222 of the cavity 40.

The medical cannula 200 is actually dip-molded at a portion other than the hot melt zone 203, and the inside diameter of the medical cannula 200 before molding is larger than the outside diameter of the support member 10, so that when the medical cannula 200 is inserted into the support member 10, as shown in fig. 7, a gap 223 exists between the medical cannula inner wall 202 and the support outer wall 12 of the support member 10. For the part of the medical cannula 200 in the hot melting zone 203, after the tip 201 of the medical cannula 200 is melted, the inner wall of the medical cannula is clung to the support outer wall 12 of the support member 10 to form the cohesion surface 13. The diameter at the clasping surface 13 is smaller than the inner diameter of the medical cannula 200 outside the hot melt zone 203, the diameter of the clasping surface 13 being consistent with the outer diameter of the support 10. Compared with the dimensional accuracy of the inner diameter of the medical cannula 200 formed by dipping outside the hot melt area 203, the cohesive surface 13 in the embodiment is formed by hot melt extrusion, and the dimensional accuracy of the inner diameter of the medical cannula 200 in the hot melt area 203 is obviously improved, so that the cohesive surface 13 can be tightly attached to the plastic tube core when in use, and the puncture resistance is effectively reduced.

Referring to fig. 3 and 4, in one embodiment, the diameter of the positioning bore 214 of the heat conducting member 21 is identical to the outer diameter of the support member 10.

In this embodiment, since the diameter of the positioning inner hole 214 of the heat conducting member 21 is identical to the outer diameter of the supporting member 10, the outer surface of the supporting member 10 can be closely attached to the inner surface of the heat conducting member 21 during the molding process, so that the tip 201 is restricted from moving forward, and the accuracy of the shape of the cavity 40 is ensured.

Referring to fig. 7, in one embodiment, the angle B formed by the tapered surface 212 and the outer surface of the support member 10 is 50-60 degrees, and the angle a formed by the reinforcing surface 211 and the outer surface of the support member 10 is 11-15 degrees.

In this embodiment, the angle B formed by the taper surface 212 and the outer surface of the supporting member 10 is 50-60 degrees, and too small an angle may cause the wall of the medical cannula 200 to wrinkle under the action of the puncture resistance, and too large an angle may cause the puncture resistance to increase sharply.

The angle A formed by the reinforcing surface 211 and the outer surface of the support member 10 is 11-15 degrees. The reinforcing surface 211 provides a rapid increase in the wall thickness of the medical cannula 200 with sufficient strength to prevent wrinkling due to puncture resistance.

In one embodiment, the length of the reinforcing surface 211 is about 3mm and the transition surface 222 is about 6mm.

Referring to fig. 4, in one embodiment, the tip forming assembly 20 further includes a positioning member 24, the positioning member 24 being coupled to the heat receptacle 22.

In this embodiment, the positioning member 24 is used for mounting and positioning of the medical cannula tip forming device 100.

During the molding process, the plastic medical cannula 200 and the support 10 are simultaneously clamped by an external clamp and pushed together toward the interior of the forward tip molding assembly 20. The tip 201 of the medical cannula 200 starts to melt after receiving the heat of the heat conducting member 21, and under the action of the extrusion force, the melted tip 201 fills the cavity 40 formed by the support member 10, the heat conducting member 21 and the heat receiving member 22 together, and after cooling, the tip 201 obtains the preset tip shape of the cavity 40.

Referring to fig. 3 and 9, in one embodiment, the heat generating component 30 includes a mounting member 31, a heat generating member 32, and a temperature sensing member 33.

The mounting piece 31 is used for being sleeved on the supporting piece 10 and connected with the tip forming assembly 20, the heating piece 32 and the temperature sensing piece 33 are both arranged on the mounting piece 31, and the heating piece 32 is in heat conduction connection with the temperature sensing piece 33.

In the present embodiment, the heat generating member 32 and the temperature sensing member 33 are both disposed on the heat conductive member 21 of the tip forming assembly 20 through the mounting member 31. In a specific embodiment, the mounting member 31 is screwed with the heat conducting member 21, and the connection surface is coated with a heat conducting paste.

The heat generating element 32 can generate an adjustable preset temperature, for example 80-220 degrees celsius, so as to melt the tip 201 of the plastic medical cannula 200.

The temperature sensing member 33 is thermally connected to the heat generating member 32. When the heat generating member 32 operates to generate heat, the heat can be efficiently transferred to the temperature sensing member 33. When the entire medical cannula tip forming device 100 reaches a stable operating state, the temperature of the temperature sensing member 33, the temperature of the support member 10, and the temperature of the heat generating member 32 are nearly uniform. Therefore, the temperature of the heat generating member 32 can be obtained by detecting the temperature of the temperature sensing member 33 by an external device. When the temperature of the heat generating element 32 is detected to be higher than the set temperature, the heat generating element 32 can stop heating, so that the temperature of the molding process can be accurately controlled.

Referring to fig. 9, in one embodiment, the heat generating member 32 includes a high-frequency heating ring 321, the temperature sensing member 33 includes a thermistor wire 331, the high-frequency heating ring 321 and the thermistor wire 331 are wound around the outer surface of the mounting member 31, and the thermistor wire 331 is disposed close to the high-frequency heating ring 321.

In this embodiment, the high-frequency heating coil 321 is a coil composed of several coils of copper wires, the number of coils is usually 5-12, and the coil can be connected with an external frequency converter, and a current with a frequency range of 50-50000 Hz is introduced. When a variable current is applied to the coil, a variable electromagnetic field is generated around the coil, and the electromagnetic field causes a vortex current to be generated in the metal, for example, the heat conductive member 21, and the vortex current causes the heat conductive member 21 to generate heat, thereby raising the temperature.

The temperature sensing element 33 comprises a plurality of turns of thermistor wire 331 tightly wound on the mounting element 31. When the high-frequency heating ring 321 is operated, the heat conductive member 21 generates a vortex current, which causes the heat conductive member 21 to generate heat, thereby raising the temperature of the heat conductive member 21, and the heat on the heat conductive member 21 can be efficiently transferred to the mount 31 through the heat conductive paste, and the heat on the mount 31 can be further efficiently transferred to the thermistor wire 331. The resistance of the thermistor wire 331 increases with an increase in temperature, and the external device obtains the current temperature of the thermistor wire 331 by detecting the resistance of the thermistor wire 331, thereby obtaining the current temperature of the heat generating element 32.

In a particular embodiment, the thermistor wire 331 may be a platinum resistance wire or a nickel resistance wire.

With continued reference to fig. 9, in one embodiment, the heat generating component 30 further includes a heat insulating member 34, the heat insulating member 34 being disposed between the high-frequency heating coil 321 and the mounting member 31.

In this embodiment, the heat insulation member 34 is disposed between the high-frequency heating coil 321 and the mounting member 31, so that the temperature of the coil of the high-frequency heating coil 321 is lower than that of the mounting member 31, thereby protecting the insulating layer on the coil and effectively reducing the failure probability of the coil caused by failure of the insulating layer or high-temperature blowing of copper wires.

In one particular embodiment, the mounting member 31 is made of silicon steel.

In this embodiment, the mounting member 31 is a silicon steel ring formed by processing silicon steel, and the heat generation amount is relatively small because the magnetic saturation intensity of the silicon steel is relatively low and the generated eddy current is relatively small, so that by this design, the main heat generating metal body around the high-frequency heating ring 321 is the heat conducting member 21, and the heat is more concentrated.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims

1. A medical cannula tip forming device, comprising: a support, a tip forming assembly, and a heat generating assembly;

the supporting piece is movably arranged in the tip forming assembly in a penetrating mode, a cavity is formed by the outer surface of the supporting piece and the inner surface of the tip forming assembly, the cavity is in a preset tip shape, a thermal resistance piece is arranged on the tip forming assembly, and the thermal resistance piece is used for controlling heat distribution of the cavity;

the tip forming assembly comprises a heat conducting piece and a heat containing piece; the heat resistance piece comprises a heat resistance groove which is arranged between the heat conduction piece and the heat capacity piece;

the thermal resistance groove is a circular groove;

the supporting piece is provided with a supporting inner hole, and the outer diameter of the supporting piece is smaller than the inner diameter of the medical cannula to be formed;

the inner surface of the heat-conducting piece comprises a reinforcing surface, a sharp conical surface and a positioning surface which are sequentially connected, and the transition surface is connected with the reinforcing surface;

the angle formed by the sharp conical surface and the outer surface of the supporting piece is 50-60 degrees, and the angle formed by the reinforcing surface and the outer surface of the supporting piece is 11-15 degrees;

the heating component is connected with the tip forming component and is used for heating the tip of the medical cannula to be formed in the cavity so as to form the tip of the medical cannula to be formed.

2. The medical cannula tip shaping device according to claim 1, wherein,

3. The medical cannula tip shaping device according to claim 2, wherein,

4. The medical cannula tip shaping device of claim 1, wherein the tip shaping assembly further comprises a positioning member coupled to the heat containing member.

5. The medical cannula tip shaping device of any of claims 1-4, wherein the heat generating component comprises a mounting member, a heat generating member, and a temperature sensing member;

6. The medical cannula tip shaping device of claim 5, wherein the heat generating member comprises a high frequency heating ring, the temperature sensing member comprises a thermistor wire, the high frequency heating ring and the thermistor wire are both wound on an outer surface of the mounting member, and the thermistor wire is disposed proximate to the high frequency heating ring.

7. The medical cannula tip shaping device of claim 6, wherein the heat generating assembly further comprises a thermal shield disposed between the high frequency heating coil and the mounting member.

8. The medical cannula tip shaping device of claim 5, wherein the mount is made of silicon steel.