JP2635556B2 - Medical tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a medical tube that can be bent using a shape memory alloy.

[Prior Art] As disclosed in Japanese Utility Model Laid-Open No. 59-2344, 30-60 ° C
It is known that a wire made of a plurality of shape memory alloys (SMA) having a transformation point is disposed in a medical tube, and the tube is bent by applying a current to the wire and heating the wire.

[Problems to be Solved by the Invention] However, since these medical tubes are used by being inserted into a living body, they need to be sterilized each time they are used. In particular, there are many cases of sterilization in an ethylene oxide gas sterilizer.

However, since the temperature inside the sterilizer often exceeds the above transformation point, the wire made of the shape memory alloy recovers to the memorized shape, especially when a plurality of wires are provided, all Since the wire rods simultaneously restore their shapes, their restoring forces repel each other. That is, since each wire is heated in a constrained state, its memory shape effect is weakened, and the memory shape is blurred (a state where it cannot be completely recovered).
Become like Also, the medical tubing itself is susceptible to damage due to its abnormal forces.

In such a situation, after the ethylene oxide sterilization treatment, the same problem is caused by the same heating also in the aeration performed for the purpose of removing the residual gas.

The present invention has been made in view of the above problems, and its purpose is to prevent the deterioration of the shape memory effect even when heated during ethylene oxide gas sterilization, etc. An object of the present invention is to provide a medical tube that can prevent damage to the subject and can easily observe even in a narrow body cavity or the like.

[Means and Actions for Solving the Problems] In order to solve the above problems, the medical tube of the present invention has a curved member made of a shape memory alloy disposed in an insertion portion, and has a shape formed by heating the curved member. In the medical tube in which the insertion section is curved by recovery, the bending member has a cross-sectional area formed to be smaller at the distal end side of the insertion section, and the start temperature of shape recovery is set to a temperature exceeding 60 ° C. It is characterized by the following.

[Embodiment] FIGS. 1 to 3 show a first embodiment of the present invention.

This embodiment shows an insertion section 1 of an endoscope as a kind of a medical tube. The insertion portion 1 is formed by connecting a bending tube portion 3 to a distal end of a flexible tube portion 2, and a distal end portion 4 is connected to a distal end of the bending tube portion 3.
Is connected. As shown in FIG. 1, the bending tube portion 3 is formed by connecting a plurality of joint pieces 5 each formed in a short tubular shape so as to be freely rotatable in a vertical direction. Blade (mesh tube) used as material
6 is fitted. Further, the outer periphery of the blade 6 is covered with an outer skin 7. As shown in FIGS. 1 and 2, an image guide fiber 8, a light guide fiber 9, a tube 10 for an air supply channel, a tube 11 for a water supply channel, and the like are inserted into the insertion portion.

A first bending member 12 is disposed on the upper side along the front-rear direction near the inner surface of the joint piece 5 in the bending tube portion 3,
Similarly, on the lower side, a second bending member 13 is provided. Each of the bending members 12 and 13 is made of a shape memory alloy, for example, a Ti—Ni-based alloy, and has a thin plate shape (for example, a thickness t = 0.15 to 0.25 mm).
Is formed. The front and rear ends of the bending members 12 and 13 are respectively inserted into fixing portions 14 and 15 formed by protruding inwardly in a U-shape into a part of the foremost bending piece 5a and a part of the rearmost bending piece 5b. It is fixed by crimping.

Further, different lead wires 16 and 17 are connected to the front and rear ends of the bending members 12 and 13, respectively, and the bending members 12 and 13 are energized through the leads 16 and 17. That is, each of the lead wires 16 and 17 is guided to the near side through the inside of the insertion portion 1 and is connected to a not-shown energizing device portion.

Here, the first bending member 12 memorizes the shape curved upward as shown by the imaginary line in FIG. 3, and the second bending member 13 lowers the shape as shown by the imaginary line in FIG. Shape memory processing is performed.

Further, the transformation point of each of the bending members 12 and 13, ie, the transformation point from the low-temperature martensite phase to the high-temperature side austenite phase is determined by the heating temperature in the sterilization process (usually 55 ° C).
(° C to 60 ° C). For example, the As point (austenite transformation start temperature) is set to 65 ° C, and the Af point (austenite transformation end temperature) is set to 70 ° C.

In this embodiment, the distal end 4 is connected to the third end.
In the case of bending upward in the drawing, electricity is supplied to the first bending member 12 through the lead wires 16 and 17, and the first bending member 12 is heated to 65 ° C. or more by resistance heat. Thereby, it can be curved upward as shown in FIG. At this time, the second bending member 13 is not energized, so that the second bending member 13 is forcibly bent upward by the recovery force of the first bending member 12.

Similarly, when bending the distal end portion 4 downward in FIG. 3, the second bending member 13 is energized and can be bent by heating to 65 ° C. or more. According to the first embodiment, the following effects can be obtained.

Since this endoscope is inserted into a living body, it is necessary to sterilize the endoscope in advance. This sterilization method usually involves EO
G (ethylene oxide gas) sterilization is widespread. In this case, the inside of the EOG sterilizer is heated to 55-60 ° C. However, according to the above configuration, since the transformation point is set to a temperature exceeding 60 ° C., the bending members 12 and 13 do not deform during the sterilization process. Therefore, it is possible to prevent the insertion portion 1 of the endoscope from being damaged due to a decrease in the heating reproducibility of the memory shape or a forcible deformation as described in the related art. Further, since a thin plate material is used for each of the bending members 12 and 13, for example, SMA having a wire diameter of the same thickness, for example, φ
It is possible to generate a recovery force larger than that of 0.15 to 0.25 mm. In order to carry out the same generated force with the linear material, the wire diameter becomes extremely thick, and the curved member enters the central portion side in FIG. 2 to press other built-in materials or to increase the filling rate. This leads to resistance of the image guide fiber 8 and the light guide fiber 9 in particular. In other words,
By using the thin plate-shaped curved members 12 and 13, it is possible to minimize the need to dispose the curved members 12 and 13 near the inner wall of the joint piece 5 as shown in FIG. Become.

 FIG. 4 shows a second embodiment of the present invention.

This embodiment is a curved member 1 in which the width on the tip side is gradually reduced.
Use 2,13. In this case, since the distal end side is deformed even when the deformation force is small in the shape recovery by energization heating, the deformation recovery speed becomes faster (the larger the cross-sectional area, the larger the deformation force required for the recovery). Therefore, the bending tube portion 3 is bent first from the distal end side. For this reason, it is easy to bend even in a narrow body cavity, and it is easy to observe.

FIG. 5 shows a third embodiment of the present invention. In this configuration, the plate widths of the bending members 12 and 13 are different between the front end portion and the rear end portion, and the front end portion is narrowed.

According to this embodiment, in addition to the effect of the second embodiment, the bending can be performed in two stages.

 FIG. 6 shows a fourth embodiment of the present invention.

In this embodiment, round bar-shaped curved members 12 and 13 are used, and the distal end side is formed in a tapered shape with a small thickness. In addition, similar bending members are provided on the left and right sides to enable bending in the left and right directions. It is to be noted that the bending in four directions can be easily achieved by making the bending member a rod shape instead of a plate shape.

The present invention is not limited to the above embodiment. For example, the bending member may be formed in a coil shape, and the coil may be contracted by heating to be bent. As a heating method, hot water, hot air, or another current-carrying heating member may be used without depending on current-carrying heating.

[Effects of the Invention] As described above, according to the present invention, deterioration of the shape memory effect of the curved member can be prevented even when heated in ethylene oxide gas sterilization or the like. In addition, the medical tube itself can be sterilized without imposing a burden on the medical tube, and its damage can be prevented. Further, since the tube bends from the distal end side during observation, the tube is easily curved even in a narrow body cavity or the like, and observation is easy.

[Brief description of the drawings]

FIG. 1 is a side end view of the first embodiment, and FIG.
3 is a side view of the same embodiment, and FIGS. 4 to 6 are perspective views respectively showing the second, third, and fourth embodiments. 1 insertion section, 3 bending section, 12, 13 bending member, 1
6, 17 ... Lead wire.

Claims (1)

(57) [Claims] 1. A medical tube in which a bending member made of a shape memory alloy is provided in an insertion portion, and the insertion portion is bent by heating the bending member to recover the shape. A medical tube characterized in that the area is made smaller at the distal end side of the insertion portion and the shape recovery start temperature is set to a temperature exceeding 60 ° C.