JP3269703B2 - Driving mechanism of treatment tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving mechanism for a treatment tool which is inserted into a body cavity to perform a treatment such as a biopsy.

[0002]

2. Description of the Related Art In such a treatment instrument, a scissor mechanism at a distal end is opened and closed in a body cavity, and a treatment instrument body is bent by a forceps raising base of an endoscope. Conventionally, there is a rapid deformation piezoelectric actuator as an actuator for driving such a mechanism (Japanese Patent Publication No. 4-52).
No. 070), and a mechanism for driving a treatment tool using this actuator has also been proposed.

[0003]

However, in the prior art, since the lead itself moves at the same time as the actuator itself moves, it is necessary to provide play on the lead so that the lead does not hinder the movement of the actuator. It is necessary to provide a space for accommodating the lead wires in the treatment instrument main body and the endoscope main body. For this reason, the treatment instrument main body and the rigid portion of the endoscope have become longer, which has caused pains for the patient into which the treatment instrument is inserted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a drive for a treatment tool capable of eliminating a play of a lead wire, shortening a rigid portion of the treatment tool or an endoscope, and reducing pain given to a patient at the time of insertion. The purpose is to provide a mechanism.

[0005]

A piezoelectric / electrostrictive element having piezoelectric or electrostrictive characteristics, a driving member attached to one end of the piezoelectric / electrostrictive element and generating a driving force;
A driving member that frictionally engages with the driving member and is driven together with the treatment tool, wherein the driving member and the driven member are applied by applying a driving signal that changes a speed of expanding and contracting the piezoelectric / electrostrictive element. The treatment instrument is driven by controlling the occurrence of slip during the treatment, so that it is unnecessary to provide a play in the lead wire for applying a drive signal to the piezoelectric / electrostrictive element, and the rigidity of the treatment instrument is reduced. Section or the rigid part of the endoscope,
It is designed to reduce the pain given to the patient during insertion.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 relate to a first embodiment of the present invention.
Shows a distal end portion of the endoscope provided with a driving mechanism of the forceps raising base of the first embodiment, and FIG. 2 shows a driving waveform.

The first embodiment is applied to an actuator for driving a forceps raising stand of an endoscope. As shown in FIG. 1, a rigid endoscope distal end portion 1 is provided with an actuator 2 which forms a driving mechanism of a forceps raising base of the first embodiment. The actuator 2 according to the first embodiment includes a piezoelectric element 3 such as Rochelle salt or PZT having piezoelectric characteristics, a vibration shaft 4 vibrated by the piezoelectric element 3, and a movement that is moved by frictionally engaging the vibration shaft 4. The actuator 2 is housed at a position in front of the forceps raising table 6 in a raising table storage section 7 in which the forceps raising table 6 is stored.

The distal end of a forceps channel 8 formed in the insertion portion is opened in the raising table storage section 7, and the forceps raising table 6 is stored in front of the opening, and is rotated by a rotating shaft 9 attached to the base end thereof. (Stand up) freely. Further, the forceps raising table 6 is urged by a spring or the like (not shown) so as to come into contact with the movable element 5. When the moving element 5 moves backward along the long axis direction of the endoscope distal end portion 2, the forceps raising table 6
Is pushed by the mover 5 and rotates clockwise about the rotation axis 9 thereof. When the forceps raising table 6 is moved forward, the forceps raising table 6 is rotated counterclockwise around its rotation shaft 9 by the urging force of a spring or the like (not shown).

The front end of the piezoelectric element 3 forming the actuator 2 is fixed to the rigid endoscope front end 1, and one end of the vibration shaft 4 is fixed to the rear end of the piezoelectric element 3. Have been. The moving element 5 that engages with the friction member 4a provided at the other end of the vibration shaft 4 has a hollow shape and frictionally engages with the friction member 4a of the vibration shaft 4 with a static friction force f1 on its inner wall.

The moving member 5 is also frictionally engaged with the inner wall surface of the endoscope distal end portion 1 with a frictional force f2. The force obtained by converting the frictional force between the forceps raising table 6 and the moving element 5 into a load on the actuator 2 is f3. The force converted into the load on the actuator 2 by the static friction force in the rotation direction of the forceps raising table 6 on the rotation axis 9 of the forceps raising table 6 is f4.

Assuming that the mass m of the moving element 5, the mass M of the forceps erecting platform 6, and the force required for bending the treatment tool are f5, the relation between each "force" is f1≥f2 + f3 + f4 + f5 + mg.
+ Mg is set. Naturally, the force F that can be generated by the piezoelectric element 3 is F ≧ f1.

An electrode of the piezoelectric element 3 is connected to a lead wire 11, which is linearly rearward along the inner wall surface of the endoscope end portion 1 (thus, requires little play). 2) It is extended and connected to a drive circuit via a switch (not shown), and a drive signal having a waveform as shown in FIG. 2 can be applied to the piezoelectric element 3 by operating the switch.

When a drive signal having a waveform as shown in FIG. 2A is applied, the piezoelectric element 3 expands and contracts in the left-right direction of FIG. 1, that is, in the longitudinal direction. Therefore, the vibration axis 4
Means that the tip is fixed to one end of the piezoelectric element 3 in the expansion and contraction direction.

Next, the operation will be described. FIG. 2 shows the piezoelectric element 3.
When a voltage pulse as shown in (a) is applied as a drive signal, the piezoelectric element 3 elongates slowly, for example, when the voltage slowly rises, and the moving element 5 that frictionally engages with the vibration shaft 4 is also shown in the drawing. Move slightly to the right to the top.

Next, when the voltage suddenly falls, the piezoelectric element 3 has an impact force that rapidly contracts, and the vibration axis 4 moves to the left with this contraction, but the vibration axis 4 slides with the moving element 5. And move to the left (in this case, the moving element 5 is not moved). As a result, the mover 5 has moved to the right as a whole.

Therefore, when the voltage pulse shown in FIG. 2A is continuously applied, the moving element 5 moves to the right by a distance much longer than the length of the expansion and contraction of the piezoelectric element 3. Therefore, the forceps raising table 6 is pushed and rotated clockwise, and is raised to be inserted through the channel 8 and bend a treatment tool such as forceps (not shown) whose tip projects from the storage section 7.

On the other hand, when a voltage pulse as shown in FIG. 2B is applied, the moving element 5 moves to the left, and the forceps raising table 6 moves.
Falls and the treatment tool returns to its original state.

In the first embodiment, since the lead wire 11 is connected to the piezoelectric element 11 which slightly expands and contracts, little play is required, so that the length of the hard tip can be shortened. Therefore, it is possible to reduce the pain given to the patient when the endoscope is inserted into the patient.

Next, a second embodiment of the present invention will be described. This embodiment shows an actuator 22 applied to an opening / closing mechanism of a forceps 21 such as a grasping forceps. Hard part 2 at the tip of flexible tube 23
A pair of arms 25, 25 that can be opened and closed is attached to 4, and an actuator 22 is attached to the base end of the arms 25, 25.

A movable element 26 forming the actuator 22 is attached to the base end of the arms 25, 25. When the movable element 26 moves back and forth in the rigid portion 24 of the forceps 21, the arms 25, 25 are linked. It opens and closes. The moving element 26 is hollow, and its inner wall is frictionally engaged with the vibration member 27. The first piezoelectric element 29 and the second piezoelectric element 30 are sandwiched between the vibrating member 27 and the front and rear.
One end in the direction of expansion and contraction is attached.

The other end (rear end) of the second piezoelectric element 30 is attached to an elastic member 31. This elastic material 31 is used for the forceps 2
It is fixed to one hard part 24. Two piezoelectric elements 2
Reference numerals 9 and 30 denote lead wires 31 extending linearly,
32, and is connected to an actuator control device 33 via
By operating a switch (not shown) connected to the actuator control device 33, a drive signal having a waveform as shown in FIGS. 4A and 4B is applied to the first and second piezoelectric elements 29 and 30, respectively. It is supposed to be.

Next, the operation of this embodiment will be described. FIG.
The voltage pulse as the drive signal shown in FIG. 4A is applied to the first piezoelectric element 29, and the voltage pulse of the second piezoelectric element 3 shown in FIG.
When the voltage is applied to 0, first, the first piezoelectric element 29 rapidly expands, and the second piezoelectric element 30 contracts rapidly.
The vibration member 27 slides rightward in the drawing.

At this time, the elastic member 31 slightly deforms. Next, the first piezoelectric element 29 contracts slowly, the second piezoelectric element 30 expands slowly, and at the same time, the deformation of the elastic material 31 returns to the original state, so that the moving element 26 moves to the left inside the rigid portion 24 of the forceps 21. I do.

If voltage pulses are continuously applied, the moving element 2
6 continues to move to the left, and the arm 25 of the forceps 21 is opened.

When the voltage pulse shown in FIG. 4 (b) is applied to the piezoelectric element 29 and the voltage pulse shown in FIG. 4 (a) is applied to the piezoelectric element 30, the moving element 26 moves to the right and the arm 25 of the forceps 21 is moved.
Closes. In addition, the speed is reduced by half even though no current is supplied to one of the piezoelectric elements, but the piezoelectric element moves.

The effect of this embodiment is almost the same as that of the first embodiment. That is, since the lead wires 31 and 32 are connected to the first and second piezoelectric elements 29 and 30 which slightly expand and contract,
Since little play is required, the length of the hard portion 24 can be reduced. For this reason, even when this treatment tool is inserted into a patient or through an endoscope channel, the pain given to the patient can be reduced. Furthermore, even if one of the piezoelectric elements breaks down, the opening / closing function of the arm of the forceps need not be lost.

Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment shows an actuator 41 constituting a drive mechanism for pulling a bending wire of a treatment instrument.

A forceps 43 is inserted through one lumen of the double lumen tube 42. A rigid tube 44 is fitted into the other lumen. An actuator 41 is provided in the rigid tube 44. The actuator 41 includes a moving element 45, a vibration shaft 46, an elastic member 47, a piezoelectric element 48, and an inertia body 49.

The moving element 45 is in frictional engagement with the inner wall of the rigid tube 44. The moving element 45 has a hollow shape, and its inner wall and the vibration shaft 46 are frictionally engaged. One end of the piezoelectric element 48 in the direction of expansion and contraction is fixed to the vibration shaft 46. An inertia body 49 is attached to the other end of the piezoelectric element 48. The lead wire 50 attached to the piezoelectric element 48
Are fixed to the lead wire fixing portion 51.

The distal end of the forceps 43 is connected to a movable element 45 and a wire 52.
Are connected via A part of the vibration shaft 46 is made of the elastic material 4
7 is fixed to the rigid tube 44. Next, the operation will be described.

When a voltage pulse having a waveform as shown in FIGS. 6A and 6B is applied to the piezoelectric element 48, the vibration axis 4 of the piezoelectric element 48 suddenly reverses its expansion or contraction speed.
6 slides against the moving element 45 under the inertial force of the inertia body 49.

When the pulse shown in FIG. 6A is applied, the vibration axis 46 slides to the left with respect to the moving element 45 in the drawing. FIG.
When the pulse of (b) is applied, it slides to the right. At this time, the elastic member 47 is also slightly deformed. Next, when the piezoelectric element 48 expands and contracts slowly, the elastic member 47 returns to the original state. Therefore, the moving element 45 slides in the hard tube 44.

When the pulse shown in FIG. 6A is applied,
When the pulse shown in FIG. 6B is applied, it slides to the left. If the pulse is continuously applied, the moving element 45 moves left and right for a long distance, and the tip of the forceps 43 is bent or returned.

When the voltage pulse shown in FIGS. 7A and 7B is applied to the piezoelectric element 48, at the time when the time differential value of the voltage changes most, the moving element is moved in the same manner as when the pulse shown in FIG. 6 is applied. 45 and the vibration axis 46 slide. At other times, the moving element 45 slides in the rigid tube 44, and the tip of the forceps 43 is bent and stretched.

In the above description, a piezoelectric element having a piezoelectric characteristic is used to generate a driving force. However, the present invention is not limited to this. For example, instead of the piezoelectric element, an electrostrictive characteristic may be used. The provided electrostrictive element may be used. or,
A magnetostrictive element having magnetostrictive characteristics may be used.

[0036]

As described above, according to the present invention, it is possible to shorten the rigid portion of the treatment tool and the endoscope, and it is possible to reduce the pain given to the patient at the time of insertion or the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a distal end portion of an endoscope provided with a driving mechanism of a forceps raising base according to a first embodiment of the present invention.

FIG. 2 is a waveform chart showing driving waveforms.

FIG. 3 is a cross-sectional view showing a treatment tool provided with a drive mechanism according to a second embodiment of the present invention.

FIG. 4 is a waveform chart showing driving waveforms.

FIG. 5 is a sectional view showing a distal end side of a double lumen tube provided with a drive mechanism according to a third embodiment of the present invention.

FIG. 6 is a waveform chart showing driving waveforms.

FIG. 7 is a waveform chart showing another driving waveform.

[Description of Signs] 1 ... Endoscope end portion 2 ... Actuator 3 ... Piezoelectric element 4 ... Vibration axis 5 ... Mover 6 ... Force lifting table 7 ... Rising table storage section 8 ... Camp force channel 9 ... Rotating axis 11 ... Lead wire

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-177214 (JP, A) JP-A-4-297252 (JP, A) JP-A-64-25833 (JP, A) 43902 (JP, U) JP 4-52070 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 1/00 334 H02N 2/00

Claims (1)

(57) [Claims] 1. A piezoelectric / electrostrictive element having a piezoelectric characteristic or an electrostrictive characteristic, a driving member attached to one end of the piezoelectric / electrostrictive element and generating a driving force, and frictionally engaging with the driving member. ,
A driven member that is driven together with the treatment tool, and controls the occurrence of slippage between the driven member and the driven member by applying a driving signal that changes the speed at which the piezoelectric / electrostrictive element expands and contracts. A driving mechanism for the treatment tool, wherein the treatment tool is driven by the drive mechanism.