JPH0346723Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to an improvement of a device for bending the distal end of a medical tube used in, for example, an endoscope in a predetermined direction.

"Prior art" The applicant has developed a bending device of this type since
62-176350 has already been provided.

As shown in FIG. 5, this bending device transforms a shape memory alloy wire 2 in which a tightly coiled coil shape is stored in advance into an open coil shape having a predetermined pitch interval to form a main body of an endoscope or the like. The heater means 3 is arranged along the inner wall surface of the flexible tube 1, and an independent heater means 3 is separately arranged in parallel to the open coil shape memory alloy wire 2.

When bending the tip of the flexible tube 1 due to the necessity of diagnosis or treatment, the heater means 3 arranged in parallel is energized, and the shape memory alloy wire 2 is brought into contact with the heater means 3. The corresponding part of
When heated above the transformation temperature, the heated portion of the shape memory alloy wire 2 changes to a pre-memorized shape,
That is, by automatically trying to deform into a tightly coiled shape, the tip of the flexible tube 1 is bent in the side direction where it is not heated due to the shape deformation.

Therefore, in such a bending device, by actively utilizing the properties of the shape memory alloy, it has become possible to easily bend the flexible tube 1 in a predetermined direction.

``Problems that the invention aims to solve'' Endoscopes are devices that are inserted into the affected area through the patient's mouth to observe the condition of the affected area through optical fibers, etc., and perform diagnosis or treatment. Therefore, the flexible tube 1 itself is always in direct contact with the patient's body cavity wall.

However, in the conventional bending device described above, the open coil shape memory alloy wire 2 disposed inside the flexible tube 1 is simply heated by the heater means 3.
Since only a configuration that heats the flexible tube 1 is adopted, when a large current is instantaneously passed through the heater means 3 to locally heat the shape memory alloy wire 2, the heat of the wire 2 is transferred to the flexible tube 1. There is a significant risk of being conducted to the patient and causing burns to the patient's body cavity walls.

For this reason, in the conventional bending device, a large current is passed through the heater means 3 to bend the shape memory alloy wire 2.
Since it is not possible to immediately heat and deform the flexible tube 1, there is a major problem in that the bending response of the tip end of the flexible tube 1 naturally deteriorates.

``Means for Solving the Problems'' Therefore, the present invention was developed to effectively solve the problems of the conventional bending devices. , and a second wire in which a predetermined curved shape is memorized in advance are arranged in a flexible tube with their tip edges fixed, and a heat shield is placed around the outer periphery of the first and second wires. A structure was adopted in which the flexible tube was bent in a predetermined direction by the deformation of the second wire, which was fitted with a close-contact coil spring and heated to a temperature above the transformation temperature.

"Function" Accordingly, in the present invention, even if a large current is momentarily passed and the second wire is heated to a temperature higher than its transformation temperature, the second wire is not fitted around the outer periphery of the second wire and the first wire. The close-contact coil spring for heat isolation reliably absorbs and disperses the heat of the second wire, effectively suppressing local heat generation and heat conduction, so that it can be used without causing burns to the patient's body cavity wall. It becomes possible to significantly improve the bending response of the tip of the flexible tube.

In addition, the presence of the heat-blocking close-contact coil spring means that when the second wire is energized and heated above its transformation temperature, it automatically deforms into a pre-memorized curved shape against the superelastic force of the first wire. At the same time, since buckling of the second wire can be effectively prevented, it is also possible to increase the bending angle of the flexible tube.

``Example'' Below, the present invention will be described in detail based on an example illustrating the present invention.As shown in FIG. It is equipped with a molded first wire 12 and a second wire 13, and a heat-blocking close-contact coil spring 15 molded from stainless steel wire, and in particular, the first wire 1
2 uses a linear shape memory alloy wire material that has been given superelasticity in accordance with a conventional method, and the second wire 13 has a curved shape, such as an inverted J shape, memorized in advance by heat treatment. It is assumed that a simple shape memory alloy wire is used.

Therefore, the first wire 12 having superelasticity is
Although its linear shape does not change even when heated, the second wire 13, which is simply a shape memory alloy wire, is in a soft martensite phase at room temperature, but when heated above the transformation temperature, it changes to the above-mentioned curved shape. It will transform automatically.

In this embodiment, as shown in FIG. 2, the tip edges of the first wire 12 and the second wire 13 are connected and fixed 14 by welding or caulking, etc., and the flexibility is achieved. The first wire 12 and the second wire 13 are disposed in the tube 11, and the opposite ends of the first wire 12 and the second wire 13 are used as lead wires to connect both wires 1.
2 and 13 are directly energized and heated, and the heat-blocking coil spring 15 made of the stainless steel wire is fitted around the outer periphery of the first and second wires 12 and 13. .

In the figure, reference numeral 16 indicates a drug solution input tube disposed in a space within the flexible tube 11, and reference numeral 17 indicates a group of optical fibers for observing the affected area.

Further, in this embodiment, when the first wire 12 and the second wire 13 are energized, the first wire 12
If the resistance of both wires 12, It is necessary to set the wire diameters of 13 to be the same.

Therefore, in a bending device having such a configuration, before heating with electricity, the first wire 12 is
The second wire 13 is deformed into a linear shape by the superelastic force of the coil spring 15 and the elastic force of the heat-blocking close coil spring 15, and is disposed within the flexible tube 11.

If the tip of the flexible tube 11 is to be bent due to the necessity of diagnosis or treatment, the first wire 12 and the second wire 13 are directly heated with electricity, and the second wire 13 in particular is heated above the transformation temperature. As shown in FIG. 3, the second wire 13
The flexible tube 11 automatically deforms into a pre-stored curved shape against the superelastic force of the first wire 12 and the elastic force of the heat-blocking close coil spring 15. The tip portion is easily bent in the direction of deformation of the second wire 13.

However, during such electrical heating, the first and second
Since a close-contact coil spring 15 made of stainless steel wire is fitted around the outer periphery of the wires 12 and 13, even if a large current is momentarily applied to the first and second wires 12 and 13, Second wire 13
Even if the second wire 13 generates heat locally, the heat of the second wire 13 is reliably absorbed and dispersed by the close coil spring 15, and local heat generation and heat conduction are effectively suppressed. It becomes possible to bend the tip of the flexible tube 11 immediately without causing burns to the wall, and the chemical solution input tube 16 and the optical fiber group 17 can also be effectively protected from heat generation.

Alternatively, simply the first wire 12 and the second wire 13
If only the tip edge 14 of the second wire 13 is fixed, when the second wire 13 is heated above the transformation temperature and automatically deforms into a pre-stored curved shape, the seat 14 will not form as shown in FIG. 4, for example. This may cause the buckling of the second wire 13 and make it impossible to utilize the deformation force of the second wire 13 effectively, but the heat-blocking close coil spring 15 of this embodiment can also effectively prevent such buckling of the second wire 13. Therefore, as a result, the flexible tube 11
It is also possible to increase the bending angle.

Furthermore, along with the above deformation of the second wire 13,
Although the first wire 12 naturally deforms, since the first wire 12 has superelasticity, there is no fear of permanent deformation.

Therefore, when the power supply to the first and second wires 12 and 13 is stopped, the second wire 13 is cooled and turns into a martensitic phase, so that the second wire 13 absorbs the superelastic force of the first wire 12, etc. As a result, it reliably deforms into a linear shape again and automatically returns to the state before energization heating.

Although not specifically shown in the drawings, it is also possible to optionally use a pair of small diameter shape memory alloy wires as the second wire 13 and to heat only the second wires in the pair, depending on the implementation. It is.

"Effects of the Invention" As described above, the present invention fixes the tip edges of a first linear wire having superelasticity and a second wire in which a predetermined curved shape is stored in advance, The first and second wires are arranged in a flexible tube, and a heat-blocking coil spring is fitted around the outer periphery of the first and second wires, and the second wire is heated to a temperature above the transformation temperature. Since the tube is characterized by bending the flexible tube in a predetermined direction, even if a large current is momentarily passed and the second wire is heated above its transformation temperature, the relationship between the second wire and the first wire is The close contact coil spring for heat isolation fitted around the outer periphery reliably absorbs and disperses the heat, making it possible to effectively suppress local heat generation and heat conduction.

Therefore, in the present invention, it is possible to instantaneously flow a large current and heat the first wire without worrying about burns on the patient's body cavity wall, so that the distal end of the flexible tube can be electrically heated. This results in a significant improvement in the bending response.

In addition, the existence of the close contact coil spring for heat isolation is such that when the second wire is heated above the transformation temperature and automatically deforms into a pre-memorized curved shape against the superelastic force of the first wire. In addition, since buckling of the second wire can be effectively prevented, it is possible to increase the bending angle of the flexible tube, thereby providing a medical tube bending device that is ideal for diagnosis and treatment. It became possible to do it.

[Brief explanation of drawings]

Fig. 1 is an exploded explanatory view showing the relationship between the first wire, the second wire, and the close contact coil spring for thermal insulation used in the bending device according to the embodiment of the present invention, and Fig. 2 shows the flexible structure of the respective members. FIG. 3 is an enlarged longitudinal cross-sectional view of the main part showing a state in which the flexible tube is disposed in the tube; FIG.
The figure is an explanatory view showing an example of buckling of the second wire, and FIG. 5 is a longitudinal cross-sectional view of a main part showing a conventional bending device. DESCRIPTION OF SYMBOLS 11... Flexible tube, 12... First wire, 13... Second wire, 15... Close contact coil spring for thermal insulation.

Claims (1)

[Scope of utility model registration request] A first straight wire having superelasticity and a second wire having a predetermined curved shape memorized in advance are arranged in a flexible tube with their tip edges fixed, and the second wire is arranged in a flexible tube. 1. A heat-blocking close-contact coil spring was fitted around the outer periphery of the second wire, so that the flexible tube was bent in a predetermined direction by deformation of the second wire heated to a temperature above the transformation temperature. A medical tube tip bending device characterized by: