JPH05184525A - Endoscope - Google Patents

Abstract

PURPOSE:To constitute the endoscope so that it is unnecessary to provide a wire of a shape memory alloy with looseness, all contraction amount of the shape memory alloy can be converted to bend the bend part, and a large bend angle can be obtained effectively. CONSTITUTION:In the endoscope provided with an inserting part 10 in which a bend part 2 consisting of plural joint pieces 4 is provided in the tip part, a shape memory alloy 8 which is provided in this inserting part 10, expands and contracts in the axial direction due to a temperature and drives to bend the bend part 4, a heating means for electrically heating this shape memory alloy 8, and a cooling means for cooling this shape memory alloy 8, a turning shaft 16 for connecting the adjacent joint pieces 4 to each other so as to be freely turnable is shifted and arranged alternately in the diameter direction from on the center axis of the inserting part 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope for bending a bending portion by utilizing the deformation of a shape memory alloy.

[0002]

2. Description of the Related Art A joint piece of a bending portion used in a conventional endoscope and its bending operation will be described with reference to FIG.

As shown in FIG. 12, an angle wire 103 is provided inside a joint piece 102 in which a plurality of joints are connected. The tip of the angle wire 103 is fixed to the tip of the endoscope or the tip of the joint piece 102.
The hand side of 3 is a pulley 1 provided in the endoscope operation section.
It is locked to 05. Then, the angle wire 103 advances and retracts due to the rotation of the pulley 105 by the hand operation,
As a result, the bending portion 101 including the joint piece 102 on the distal end side
Bends in a predetermined direction.

During this bending operation, the center axis of rotation (pin shaft 104) between the joint pieces passes through the center of the joint piece 102, which is why the angle wire 103 is bent.
One is pulled out from the bending portion 101 to the rear insertion portion,
On the other hand, the other angle wire 103 is adapted to be drawn from the insertion portion to the bending portion by the same length.

[0005]

By the way, when a shape memory alloy wire (hereinafter referred to as SMA wire) is connected to an angle wire in the curved portion of the above structure and a bending is attempted by contraction due to heating of the SMA wire. As much as the angle wire on the non-heating side is drawn into the bending portion, the SMA wire needs to have slack, and this slack causes a problem of loss of bending amount due to heat shrinkage.

The present invention has been made by paying attention to the above-mentioned problems, and it is not necessary to give slack to the SMA wire, and the entire shrinkage amount of the SMA wire can be used for bending, which is highly efficient. The object is to provide an endoscope that can obtain a large bending angle.

[0007]

According to the present invention, there is provided an insertion portion having a curved portion composed of a plurality of joint pieces at its tip portion, and an insertion portion provided in the insertion portion, which expands and contracts in the axial direction depending on temperature. In an endoscope including a shape memory alloy that drives a bending portion to bend, a heating unit that electrically heats the shape memory alloy, and a cooling unit that cools the shape memory alloy, the adjacent joint pieces are rotated relative to each other. It is characterized in that rotating shafts that are freely connected are arranged so as to be alternately displaced from the center axis of the insertion portion in the radial direction.

Therefore, when one of the shape memory alloys is electrically heated to bend the bending portion, the bending portion has a rotating shaft along the outer surface of the joint piece on which the non-heating side shape memory alloy is arranged. Since the shape-memory alloy on the non-heating side does not slide because it bends in the center, the wire of the shape-memory alloy and the angle wire do not loosen, and the expansion and contraction of the shape-memory alloy is efficiently converted into a bending operation.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show the basic structure of a bending portion of an endoscope according to a first embodiment of the present invention. Figure 1
As shown in (a) and (b), the main body of the bending portion 2 of the present embodiment is composed of a plurality of joint pieces 4 connected to each other, and inside thereof, a pair of tips whose ends are fixed to the tip portions of the bending portion 2. The angle wire 6 is inserted. Although not shown, a CCD, a CCD cable, an image guide, a light guide fiber, or the like is provided as an internal component of the optical system.

The base end of each angle wire 6 is mechanically connected to a shape memory alloy wire 8 (hereinafter referred to as SMA wire) arranged in an insertion portion 10 connected to the rear of the bending portion 2, The rear end of each SMA wire 8 is mechanically fixed to the inner wall of the flexible tube of the insertion portion 10. Also, SMA
Conductive lead wires 12 are electrically connected to both ends of the wire 8 so that each SMA wire 8 can be selectively energized and heated by an energizing operation on the hand side.

As shown in FIG. 1C, a plurality of joint pieces 4 in the bending portion 2 are rotatably connected to each other by a pin (rotating shaft) 16, and the connecting portion 14 has a pin 16. Is located along the outer periphery of the joint piece 4, and a hinge 22 around the pin 16 is provided.

Next, the operation of the first embodiment will be described.

In the bending portion 2 composed of the joint piece 4 having the above-mentioned structure, one of the SMA wires 8b is operated by a power supply operation on the hand side.
2B, the angle wire 6 connected to the tip end side of the SMA wire 8b slides backward from the bending portion 2 and the tip end of the angle wire 6 is contracted. Since the distal end portion of the endoscope to which is fixed is pulled, the bending portion 2 is bent by the length of contraction of the SMA wire 8b. At this time, the joint piece 4 is unheated with the SMA wire 8a.
Since the pin 16 along the outer surface of the joint piece 4 on the side of the angle wire 6 connected to is curved about the rotation center, the angle wire 6 connected to the SMA wire 8a on the non-heating side does not slide.

That is, since it is not necessary to provide the SMA wire 8 with slack unlike the conventional case, the contraction of the SMA wire 8 can be efficiently converted into the bending operation. And SM
When the energization amount to the A wire 8 is reduced or stopped, the SMA wire 8 is cooled by the air supply by a pump described later, and as a result, the SMA wire 8 is extended and the bending portion 2 is restored by the restoring force of the endoscope built-in object. Returns to a straight line.

In this embodiment, since the SMA wire connected to the angle wire can be provided in the insertion portion without slackening, the SMA wire is not heated and shrunk more than necessary, and the amount of electricity applied is smaller than in the conventional case. The desired curvature is obtained. Therefore, it is possible to observe the object to be inspected by a bending operation that is electrically and temperature safe and has a high responsiveness.

As shown in FIG. 1D, the bending portion 2
Curved tube 1 made of elastic material such as resin and having a notch
8, the bending operation may be configured such that the center of rotation of each piece is located along the outer circumference of the bending tube 18 as in the joint piece 4 described above.

Next, a second embodiment of the present invention will be described with reference to FIGS.
Will be described with reference to.

As shown in FIG. 3, the endoscope 30 of the present embodiment.
Is composed of a long flexible tube 32, a bending section 2 provided at the tip of the flexible tube 32, and an optical system (not shown) provided at the tip of the bending section 2. The bending portion 2 is composed of a bending tube similar to that of the first embodiment, and can be bent by the bending mechanism portion 60. The bending portion 2 and the flexible tube 32 are connected by a flexible tube base 34.

In the bending mechanism section 60, the angle wire 6 fixed to the tip of the bending section 2 is connected to the SM via the connecting member 36.
It is connected to the A wire 8. In addition, SMA wire 8
A part of the angle wire 6 is inserted into an incompressible member 38, for example, a coil sheath, and the proximal ends of the incompressible member 38 and the SMA wire 8 are connected to a joint 40.

As shown in FIGS. 4 (a) and 4 (b), the joint 40 is formed of a cylindrical member having an end face having a plurality of holes, and is formed of a non-conductive member. The tip of the incompressible member 38 is brazed and fixed to the connecting member 42, and the rear side can be freely curved.

An air tube 44 is connected to the rear of the bending mechanism 60 by a joint 40, the rear end of the air tube 44 is connected to a solenoid valve 46, and the solenoid valve 46 is a pump 48.
And are connected by air piping.

Further, the solenoid valve 46, the pump 48, and the SMA wire 8 are electrically connected to the control device 50, and the joystick 52 and the sub-switch 54 connected to the control device 50 are operated to operate these drive parts. You can do it. That is, the bending portion 2 is bent in an arbitrary direction by the joystick 52, and the sub switch 54 provided on the joystick 52 causes the joystick 52 to move as shown in FIG.
As shown in FIG. 5, the SMA wire 8 is energized and the pump is driven and controlled. Next, the operation of the second embodiment will be described.

First, when operating the endoscope 30, by turning on the sub switch 54, preparation for energization of the SMA wire 8, that is, bending operation by operating the joystick 52 can be performed, and at the same time, the switch of the pump 48 can be operated. As it enters, the pump starts to move and sends cooling air.
Here, when the joystick 52 is tilted in a direction corresponding to the direction in which the bending section 2 is bent, a signal is input to the control device 50 and the SMA wire 8 in the bending direction is electrically heated.
As a result, the SMA wire 8 contracts, and the contracting force pulls the angle wire 6 to bend the bending portion 2. At this time, the control device 5 is arranged so as not to send the cooling air to the air tube 44 corresponding to the SMA wire 8 which is energized.
At 0, the solenoid valve 46 selectively closes the valve.

When the sub switch 54 is turned off, the pump 48 is switched off, the pump 48 is stopped, and the SMA wire 8 cannot be heated by energization. That is, even if the joystick 52 is tilted, the SMA wire 8 is not energized.

Therefore, in this embodiment, since the SMA wire cannot be heated while the cooling device is not operating, the cooling device is always operating when the bending operation is performed, and the cooling device is operated without moving it by mistake. It is safe without. Further, the response speed of bending can be increased.

FIG. 5 shows a third embodiment of the present invention.

In addition to the structure of the second embodiment, this embodiment has a pump 48 for supplying cooling air as shown in FIG. 5 (a).
The piezoelectric element 58 is provided in the air pipe immediately after the
The signal from 8 is input to the control device 50. Further, in the second embodiment, the sub switch 5
4 is a drive switch of the pump 48 and S as shown in FIG.
Although it also serves as both the switch for energizing the MA wire 8, in the present embodiment, it may have only the function of the switch for energizing the SMA wire 8. The other structure is the same as that of the second embodiment.

In the third embodiment, when the cooling air is supplied from the pump 48, the pressure in the air pipe becomes high.
The pressure is detected by the piezoelectric element 58 provided at the rear end of the pump 48, and as shown in the block diagram of FIG.
When a signal is input to the SMA wire 8 and the joystick 52 is further tilted in response to the signal, the SMA wire 8 can be electrically heated. Here, the piezoelectric element 58 and the SMA energizing circuit 5
6. Since the joystick 52 is connected in series, the SMA wire 8 will not be energized if the signal is cut off midway.

Therefore, in this embodiment, as in the second embodiment, the SMA wire cannot be heated in the state where the cooling device is not operating, so the cooling device is always operating when performing the bending operation, and the cooling device is mistakenly operated. It is safe to operate without moving.

FIG. 6 shows a first modification of the detection mechanism for detecting the operation of the pump 48 described in the third embodiment.

In the first modification, a propeller 60, a small motor 62 and a belt 64 are provided in place of the piezoelectric element 58 of the third embodiment, and the propeller 60 and the small motor 6 are provided.
The belt 2 is connected to the two.

Therefore, when the cooling air is supplied from the pump 48, the propeller 60 in the air pipe is rotated by the wind force, and the small motor 62 is rotated through the belt 64 to generate electricity. By inputting this electric signal to the control device 50, it can be determined whether or not the cooling air is supplied.

FIG. 7 shows a second modification of the detection mechanism.

In the second modification, as a mechanism for detecting whether or not the cooling air is supplied from the pump 48, FIG.
As in (a) and (b), an elastic member 68 fixed via a fixing member 66 in the air pipe immediately after the pump 48, and an air receiving member 70 having a plurality of holes fixed to the elastic member 68. And the two electrical contacts 72 in the pipe and the stopper 7
4 is provided with a mechanical sensor 76. Then, the electrical contact 72 of the mechanical sensor 76 and the SMA wire 8
And are connected in series via the control device 50.

Therefore, when the cooling air is supplied from the pump 48, the elastic member 66 is extended when the air receiving member 70 receives the wind force of the cooling air as shown in FIG.
0 moves to the position of the stopper 74. At this time, the two electrical contacts 72 are closed and a signal is input to the control circuit 50.
On the other hand, when the pump 48 is stopped, the cooling air is not supplied and the electric contact 72 is opened as shown in FIG. That is,
In this modified example, the air receiving member 70 and the electrical contact 72 are used as a switch that plays the same role as the sub switch 54 provided in the joystick 52 in the second embodiment.

FIG. 8 shows a third modification of the detection mechanism.

In the third modification, as shown in FIG. 8, a semiconductor pressure gauge 80 is provided branching from the pipe immediately after the pump 48.

Therefore, when the pump 48 is operating and supplying cooling air, the pressure in the air pipe becomes high, and the pressure gauge 80 detects this pressure and outputs a signal to the control device 50. This determines whether the pump 48 is moving.

FIG. 9 shows a fourth modification of the detection mechanism.

In the fourth modification, a thermocouple 82 is embedded in the pipe immediately after the pump 48.

Therefore, when the cooling air is supplied, the temperature inside the pipe becomes low, and when the supply of the cooling air is stopped, the temperature becomes slightly high. By detecting this temperature difference with the thermocouple 82, it is determined whether or not the pump 48 is operating.

FIG. 10 shows a fourth embodiment of the present invention.

In addition to the structure of the second embodiment, this embodiment
A rubber seal member 84 as shown in FIG. 10B is provided at the rear part of the connecting member 42 that connects the flexible tube 32 and the bending portion 2 shown in FIG. 10A. The rubber seal member 84 has four holes, and the incompressible member 38 is press-fitted and inserted into the holes.
Are press-fitted into the flexible tube 32.

The rubber seal member 84 has an outer diameter slightly larger than the inner diameter of the flexible tube 32, and the hole for inserting the incompressible member 38 has an inner diameter slightly smaller than the outer diameter of the incompressible member 38. is doing. Further, as shown in FIG. 10C, a safety valve 71 is provided at the open portion of the solenoid valve 46. In addition,
In particular, the safety valve 71 may not be provided.

In the present embodiment, when cooling the SMA wire 8 that has been electrically heated, the cooling air supplied from the pump 48 flows from the solenoid valve 46 through the air tube 44 to the tip, and the inside of the bending portion 2 is When it is filled with cooling air, it passes through the air tube 44 on the opposite side and is exhausted to the outside via the solenoid valve 46. At this time, since the air pressurized by the pump 48 is being sent in front of the rubber seal member 84, the pressure is high. This pressure is adjusted by a safety valve 71 attached to the outside air opening portion of the solenoid valve 46 and has a constant high pressure, so that it is difficult for gas and the like to enter the inside of the bending portion 2 from the outside. Even if gas enters from the outside, it always passes through the air tube 44 and is exhausted to the outside.
Even if the safety valve 71 is not provided, since pressurized cooling air is supplied, the inside of the bending portion 2 is pressurized to a high pressure.

In this embodiment, since air is sent while being pressurized by the pump 48, the internal pressure of the bending portion 2 becomes high, and it is difficult for fluid such as gas or water to enter from the outside. Further, even if a flammable gas enters from the outside, it is exhausted to the outside through the inside of the air tube 44, so it is safe as long as no electrical contact is placed in the air tube 44.

FIG. 11 shows a modification of the rubber seal member in the fourth embodiment.

In this modification, a holding member 86 for holding the tip of the incompressible member 38 is provided as shown in FIG. 11 (a), which plays the same role as the rubber seal member 84. An O-ring 88 is attached in the groove of the peripheral surface of 86 as shown in FIG. And
The O-ring 88 seals the holding member 86 and the coupling member 42.

The present invention is not limited to the above embodiments and modifications. For example, in the second embodiment, a means for inspecting the operation of the pump is provided immediately after the pump. It may be provided immediately after the solenoid valve between the SMA wires. In this case, even if the solenoid valve fails and cooling air is not sent, the SMA wire is not energized and heated,
Safety is further improved.

[0051]

As described above, in the endoscope of the present invention, the wire of the shape memory alloy can be provided inside the insertion portion without slackening, so that it is not necessary to heat-shrink the shape memory alloy more than necessary. In addition, since a desired bending angle can be obtained with a smaller amount of electric current than the conventional one, it is electrically and thermally safe, and the operability of the endoscope can be improved.

[Brief description of drawings]

FIG. 1A is a configuration diagram showing a bending portion of an endoscope according to a first embodiment of the present invention, and FIG. 1B is a perspective view of the bending portion.
(C) is a perspective view showing a connecting portion of the curved portion, and (d) is a perspective view showing a modified example of the curved portion.

2A and 2B are explanatory views showing the operation of the bending portion of the endoscope according to the first embodiment.

FIG. 3 is a configuration diagram of an endoscope according to a first embodiment of the present invention.

4A is a cross-sectional view of the air tube joint shown in FIG. 3, FIG. 4B is a cross-sectional view taken along the line AA of FIG.
(C) is a block diagram of an SMA wire cooling mechanism.

5A is a configuration diagram of an SMA wire cooling mechanism incorporated in an endoscope according to a third embodiment of the present invention, and FIG. 5B is a control block diagram of the cooling mechanism.

FIG. 6 is a configuration diagram showing a first modification of the SMA wire cooling mechanism incorporated in the endoscope.

7A is a configuration diagram showing a second modification of the SMA wire cooling mechanism, FIG. 7B is a sectional view taken along line BB of FIG. 7A, and FIGS. It is explanatory drawing which shows operation | movement of a member.

FIG. 8 is a configuration diagram showing a third modification of the SMA wire cooling mechanism.

FIG. 9 is a configuration diagram showing a fourth modification of the SMA wire cooling mechanism.

10A is a configuration diagram of an insertion portion of an endoscope according to a fourth embodiment of the present invention, FIG. 10B is a perspective view of a rubber seal member shown in FIG. 10A, and FIG. It is a partial view of the cooling mechanism which has.

FIG. 11A is a sectional view showing a modification of the fourth embodiment,
(B) is the same perspective view.

12 (a) and 12 (b) are explanatory views showing the operation of the bending portion in the conventional endoscope.

[Explanation of symbols]

2 ... Bending part, 4 ... Joint piece, 6 ... Angle wire, 8 ... S
MA wire (shape memory alloy), 10 ... insertion part, 16 ... pin (rotating shaft).

Claims (1)

[Claims] 1. An insertion portion having a bending portion formed of a plurality of joint pieces at a distal end portion, and a shape memory alloy which is provided in the insertion portion and expands and contracts in the axial direction by temperature to drive the bending portion to bend. In an endoscope equipped with a heating means for electrically heating the shape memory alloy and a cooling means for cooling the shape memory alloy, a rotary shaft for rotatably connecting adjacent joint pieces to each other is inserted. An endoscope characterized in that the endoscopes are arranged so as to be alternately displaced in the radial direction from the central axis of the part.