JPH07350A - Driving mechanism of treatment tool - Google Patents

Abstract

PURPOSE:To almost dispense with a play on a lead wire, shorten the hard sections of a treatment tool and an endoscope, and reduce the pain given to a patient at the time of insertion by applying the drive signal changing the expanding/shrinking speed of a piezoelectric/electrostrictive element, and controlling the occurrence of a slip between a driving member and a driven member. CONSTITUTION:A piezoelectric element 3 having a piezoelectric characteristic, a vibration shaft 4 fitted to its one end and vibrated, a shift piece 5 friction- coupled with the vibration shaft 4, and a forceps erection base 6 pressed and driven by the shift piece 5 are stored in the erection base storage section 7 of an endoscope tip section 1. The drive signal is applied to the piezoelectric element 3 via a linearly arranged lead wire 11. The occurrence of a slip between the vibration shaft 4 and the shift piece 5 is suppressed, a play is rarely required on the lead wire 11, the forceps erection base 6 erecting a treatment tool is rotatively driven, the hard sections of the treatment tool and an endoscope can be shortened, and the pain given to a patient at the time of insertion is reduced.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In such a treatment instrument, the scissor mechanism at the tip is opened and closed in the body cavity, and the treatment instrument main body is curved by the forceps raising base of the 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 instrument using this actuator has also been proposed.

[0003]

However, in the prior art, since the lead wire moves at the same time because the actuator itself moves, it is necessary to provide play in the lead wire so that the lead wire does not hinder the movement of the actuator. It was necessary to provide a space for accommodating the lead wires in the treatment instrument body or the endoscope body. As a result, the treatment tool main body and the rigid portion of the endoscope become long, and the patient into which the treatment tool is inserted suffers pain.

The present invention has been made in view of the above-mentioned points, and the drive of the treatment instrument which can eliminate the play of the lead wire to shorten the rigid portion of the treatment instrument or the endoscope and reduce the pain to the patient at the time of insertion. The purpose is to provide a mechanism.

[0005]

Means and Actions for Solving the Problems A piezoelectric / electrostrictive element having a piezoelectric characteristic or an electrostrictive characteristic, and a driving member attached to one end of the piezoelectric / electrostrictive element to generate a driving force.
The driven member and the driven member are provided by applying a driving signal that has a driven member that is frictionally engaged with the driving member and is driven together with the treatment tool, and that changes a speed at which the piezoelectric / electrostrictive element expands and contracts. By controlling the occurrence of slippage between the treatment tool and driving the treatment tool, it is not necessary to provide a play in the lead wire for applying the drive signal to the piezoelectric / electrostrictive element, and the rigidity of the treatment tool is reduced. Section or the rigid part of the endoscope is shortened,
It is designed to reduce the pain 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 the tip of the endoscope provided with the drive mechanism for the forceps raising base of the first embodiment, and FIG. 2 shows the drive waveform.

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

The tip of a forceps channel 8 formed in the insertion portion is opened in the raising base storage portion 7, the forceps raising base 6 is stored in the front position of this opening, and the forceps raising base 6 is rotated by a rotary shaft 9 attached to the base end thereof. (Standing up) Free. The forceps raising base 6 is biased by a spring or the like (not shown) so as to come into contact with the movable body 5. When the mover 5 moves backward along the long axis direction of the endoscope distal end portion 2, the forceps raising base 6
Is pushed by the mover 5 and rotates clockwise about its rotation axis 9. Further, when it moves forward, the forceps raising base 6 is rotated counterclockwise about its rotation axis 9 by the urging force of a spring or the like (not shown).

The tip end of the piezoelectric element 3 forming the actuator 2 is fixed to the rigid endoscope tip 1, and one end of the vibration shaft 4 is fixed to the rear end of the piezoelectric element 3. Has been done. The mover 5 engaging with the friction member 4a provided at the other end of the vibrating shaft 4 has a hollow shape and frictionally engages the inner wall of the moving member 5 with the friction member 4a of the vibrating shaft 4 by the static friction force f1.

The mover 5 is also frictionally engaged with the inner wall surface of the endoscope distal end portion 1 by a frictional force f2. The force obtained by converting the frictional force between the forceps raising base 6 and the mover 5 into a load on the actuator 2 is f3. The force obtained by converting the static frictional force in the rotating direction of the forceps raising base 6 on the rotary shaft 9 of the forceps raising base 6 into the load on the actuator 2 is f4.

Assuming that the mass m of the mover 5, the mass M of the forceps raising base 6 and the force required to bend the treatment tool are f5, the relationship between the "forces" is f1≥f2 + f3 + f4 + f5 + mg.
It is set to be + Mg. Naturally, the force F that can be generated by the piezoelectric element 3 is F ≧ f1.

A lead wire 11 is connected to the electrode of the piezoelectric element 3, and the lead wire 11 is linearly rearward along the inner wall surface of the endoscope distal end portion 1 (thus, almost no play is required). ) It is extended and connected to a drive circuit through 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, the longitudinal direction. Therefore, the vibration axis 4
Has its tip fixed to one end of the piezoelectric element 3 in the expansion / contraction direction.

Next, the operation will be described. The piezoelectric element 3 is shown in FIG.
When a voltage pulse as shown in (a) is applied as a drive signal, the piezoelectric element 3 expands slowly, for example, when the voltage rises slowly, and the mover 5 frictionally engaged with the vibration shaft 4 is also shown in the drawing. Move slightly to the right.

Next, when the voltage suddenly falls, the piezoelectric element 3 becomes an impact force that abruptly contracts, and the vibrating shaft 4 moves to the left with this contraction, but the vibrating shaft 4 slips with the mover 5. It occurs and moves to the left (in this case, the mover 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 mover 5 moves to the right for a distance much longer than the length of expansion and contraction of the piezoelectric element 3. Therefore, the forceps raising base 6 is pushed and rotated in the clockwise direction, and by standing up, the forceps raising base 6 is inserted through the channel 8 and the treatment tool such as forceps (not shown) whose tip projects from the storage portion 7 can be curved.

On the other hand, when a voltage pulse as shown in FIG. 2 (b) is applied, the mover 5 moves to the left on the contrary, and the forceps raising base 6 is moved.
Collapses and the treatment tool returns to its original position.

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 portion can be shortened. For this reason, it is possible to reduce the pain caused 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 forceps 21 such as grasping forceps. Hard part 2 at the tip of flexible tube 23
A pair of arms 25, 25 that can be opened and closed are attached to the arm 4, and an actuator 22 is attached to the base ends of the arms 25, 25.

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

The other end (rear end) of the second piezoelectric element 30 is attached to the elastic material 31. This elastic material 31 is the forceps 2
It is fixed to the rigid part 24 of No. 1. Two piezoelectric elements 2
Reference numerals 9 and 30 denote lead wires 31 extending linearly,
Connected to the actuator control device 33 via 32,
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 done.

Next, the operation of this embodiment will be described. Figure 4
The voltage pulse as the drive signal shown in (a) is applied to the first piezoelectric element 29, and the voltage pulse second piezoelectric element 3 shown in FIG.
When applied to 0, first piezoelectric element 29 suddenly expands and second piezoelectric element 30 suddenly contracts.
The vibrating member 27 slides to the right in the drawing.

At this time, the elastic material 31 is slightly deformed. Next, the first piezoelectric element 29 contracts slowly, the second piezoelectric element 30 slowly expands, and at the same time, the deformation of the elastic material 31 returns to the original state, whereby the mover 26 moves to the left in the rigid portion 24 of the forceps 21. To do.

If voltage pulses are continuously applied, the mover 2
6 continues to move to the left, and the arm 25 of the forceps 21 opens.

When the voltage pulse shown in FIG. 4B is applied to the piezoelectric element 29 and the voltage pulse shown in FIG. 4A is applied to the piezoelectric element 30, the mover 26 moves to the right to move to the arm 25 of the forceps 21.
Closes. Also, even if one of the piezoelectric elements is not energized at all, the speed will decrease but will move.

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 that slightly expand and contract,
Since little play is required, the length of the hard portion 24 can be shortened. Therefore, even when the treatment tool is inserted into the patient or when it is inserted through the channel of the endoscope, the pain to the patient can be reduced. Further, even if one of the piezoelectric elements fails, the open / close function of the arm of the forceps does not have to be lost.

Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment shows an actuator 41 that constitutes a drive mechanism that pulls a bending wire of a treatment tool.

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

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

The tip of the forceps 43 has a mover 45 and a wire 52.
Are connected via. A part of the vibrating shaft 46 is made of elastic material 4.
It is fixed to the rigid tube 44 via 7. 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, when the piezoelectric element 48 suddenly reverses its expansion or contraction speed, it vibrates.
6 receives the inertial force of the inertial body 49 and slides with respect to the moving element 45.

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

When the pulse shown in FIG. 6A is applied, to the right,
When the pulse of FIG. 6 (b) is applied, it slides to the left. If the pulse is continuously applied, the mover 45 moves left and right for a long distance to bend or return the tip of the forceps 43.

When the voltage pulse of FIG. 7A or FIG. 7B is applied to the piezoelectric element 48, the moving element is moved in the same manner as when the pulse of FIG. 45 and the vibration shaft 46 slide. At other times, the mover 45 slides in the rigid tube 44, and the tip of the forceps 43 is bent and stretched.

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

[0036]

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

[Brief description of drawings]

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

FIG. 2 is a waveform diagram showing drive waveforms.

FIG. 3 is a 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 diagram showing drive waveforms.

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

FIG. 6 is a waveform diagram showing drive waveforms.

FIG. 7 is a waveform diagram showing another drive waveform.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... End part of endoscope 2 ... Actuator 3 ... Piezoelectric element 4 ... Oscillation axis 5 ... Mover 6 ... Forceps raising base 7 ... Raising base storage 8 ... Forceps channel 9 ... Rotating shaft 11 ... Lead wire

Claims (1)

[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 engaged with the driving member. ,
A driven member that is driven together with a treatment tool, and controls the occurrence of slippage between the driving member and the driven member by applying a driving signal that changes the speed at which the piezoelectric / electrostrictive element expands and contracts. A drive mechanism for a treatment instrument, characterized in that the treatment instrument is driven by a lever.