JPS6346688B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible tube for an endoscope whose degree of flexibility can be changed.

In general, for flexible endoscopes that are inserted into body cavities and used for internal observation and examination, it is difficult to adapt the soft endoscopes to the extent that the softness, or hardness, of the flexible tube can be changed depending on the situation during use. Because of the inconvenience of severely restricting the area, an endoscope has been proposed in which the operator can change the hardness of the soft tube.

Conventionally, in order to change the hardness of a soft tube, as shown in Japanese Patent Publication No. 51-38197, a spiral tube is placed inside the core tube of the soft tube, and the tip of this spiral tube is The proximal end of the helical tube was connected to an operating section that could fix the helical tube and change the diameter of the helical tube. In other words, by rotating the operating section, the helical tube is fed into the core tube to enlarge its diameter, and the helical tube is brought into pressure contact with the inner circumferential surface of the core tube, thereby making the soft tube portion hard.

However, with this configuration, when a long flexible tube is required, such as in a colonoscope, the stroke of feeding the spiral tube is very long in order to make the entire flexible tube rigid. Since it is long, it is extremely difficult to operate. Additionally, if the soft tube is bent in a complicated manner within the body cavity, the spiral tube will not be evenly pressed against the entire core canal, causing problems such as uneven hardness of the soft tube. Ta.

This invention has been made based on the above circumstances, and its purpose is to easily change the hardness of the soft tube by forming the spiral tube with a shape memory alloy whose diameter changes with temperature changes. To provide a flexible tube for an endoscope that can be changed evenly and uniformly.

An embodiment of the present invention will be described below with reference to the drawings. 1 in the figure is an endoscope. This endoscope 1 consists of an operating section 2 and an insertion section 3, and the operating section 2 is provided with an eyepiece section 4 that can observe the inside of the body cavity through an observation optical system (not shown). Universal cord 5 is connected. A connector 6 is provided at the end of the universal cord 5, and the connector 6 is connected to a light source device (not shown).

The insertion section 3 includes a distal end forming section 9 provided at the distal end of a flexible tube section 7 via a curved tube section 8 . The soft tube section 7 has a mesh tube 1 on the outside of the spiral core tube 10.
1 are stacked one on top of the other, and this net pipe 11 is covered with an outer skin 12 made of thermoplastic synthetic resin. Further, a spiral tube 13 wound in the opposite direction to the core tube 10 is inserted into the core tube 10 of the soft tube portion 7, with its tip end fixed to the core tube 10. This spiral tube 13 is
It is made of shape memory alloys such as Cr-Zn-Al alloys and Ti-Ni alloys. That is, when the helical tube 13 is in the matrix phase at high temperature, the outer circumferential surface is in pressure contact with the inner circumferential surface of the core tube 10 as shown in FIG. 3, and when it is in the martensitic phase at room temperature, the diameter is as shown in FIG. As shown in FIG. 2, the diameter dimension is such that the outer circumferential surface is slightly separated from the inner circumferential surface of the core tube 10. Furthermore, the shape memory alloy from which the spiral tube 13 is formed has a temperature at which the reverse transformation from the martensitic phase to the parent phase begins, which is higher than body temperature.

Further, a pair of first lead wires 14, 14 are connected to the spiral tube 13. That is, one first lead wire 14 has one end connected to the helical tube 13 at its tip, and the other first lead wire 14 has one end connected to the rear end of the helical tube 13. The other ends of these first lead wires 14, 14 are connected to a switch 15 provided on the operating section 2. A pair of second lead wires 16, 16 are connected to this switch 15. These second lead wires 16, 16
are inserted into the universal cord 5 and electrically connected to pins 17, 17 protruding from the connector 6. When the connector 6 is inserted into the light source device, the pins 17, 17 are connected to the power source in the light source device.

In addition, the spiral tube 13 and the lead wires 14, 14, 1
6 and 16 are insulated with Tefcoat.

Next, the operation of the above configuration will be explained. First, when the switch 15 is turned off, the helical tube 13 is not heated and is in the martensitic phase, so that the helical tube 13 has a shape with a gap between it and the core tube 10. Therefore, the soft tube portion 7 is kept in a soft state.

If it is desired to harden the soft tube section 7, turn on the switch 15. Then, the helical tube 13 is heated to a temperature higher than the temperature at which it generates resistance heat due to the energization and starts reverse transformation, so the helical tube 13 returns from the martensitic phase to the parent phase, and its outer periphery changes as shown in FIG. The surface is pressed against the inner circumferential surface of the core tube 10. That is, since the helical tube 13 deforms due to the shape memory effect, its entire outer circumferential surface is uniformly pressed against the inner circumferential surface of the core tube 10, regardless of the bent state of the flexible tube section 7. Therefore, the soft tube portion 7 becomes uniformly hard over its entire length.

Furthermore, when the switch 15 is turned off, the spiral tube 13 stops generating resistance heat due to energization and is cooled below the temperature at which reverse transformation starts, so the state returns to the state shown in FIG. 2 and the soft tube portion 7 becomes soft.

As described above, the present invention provides that the inner side of the core tube of the soft tube has a diameter smaller than that of the core tube at room temperature.
Since a helical tube made of a shape memory alloy whose shape changes so as to come into pressure contact with the inner peripheral surface of the core tube at high temperatures is provided, the flexible tube can be made hard by heating this helical tube and bringing it into pressure contact with the core tube. I can do it. In other words, the hardness of the soft tube can be increased by the shape memory effect of the spiral tube, so it is not only possible to make the entire length of the soft tube uniformly hard regardless of the bending state of the tube, but also to change the hardness. It is also extremely easy to operate.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic configuration diagram of an endoscope, Fig. 2 is a sectional view of the soft tube section in a soft state, and Fig. 3 is a sectional view of the soft tube section in a hard state. FIG. 7... Soft tube section, 10... Core tube, 13... Spiral tube.

Claims (1)

[Claims] 1. A helical tube made of a shape memory alloy is arranged inside the core tube of the flexible tube, the diameter of which becomes smaller than the core tube at room temperature, and whose shape changes so that it comes into pressure contact with the inner circumferential surface of the core tube at high temperatures. A flexible tube for endoscopes.