JP4059739B2 - Expandable grasping forceps - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expandable grasping forceps for grasping an object to be collected by expanding a grasping portion at a distal end in order to perform various collection procedures such as polyp collection and biopsy in the body.
[0002]
[Prior art]
For example, grasping forceps that are introduced into the body through a treatment instrument insertion channel of an endoscope and are used to grasp and collect a foreign substance in the body or to collect a test cell tissue or the like have conventionally been various. Kinds are known.
[0003]
Such a grasping forceps is provided on the proximal side of the insertion portion, for example, an insertion portion made of a metal coil sheath whose outer periphery is covered with an outer tube, an operation wire inserted in the insertion portion so as to be able to advance and retract. And an operation portion for pushing and pulling the operation wire, and a grip portion provided on the distal end side of the operation wire, and the operation wire is pushed and pulled by the operation portion, thereby The grip part is opened and closed so that foreign matter can be gripped by the grip part.
[0004]
Various types of means for opening and closing the gripping portion at the tip end by pushing and pulling the operation wire are conventionally known. For example, an expansion-type gripping forceps (a practical example of Japanese Utility Model Laid-Open No. 5-9517 and Japanese Patent Application Laid-Open No. 8-98839) in which a spreading habit is imparted to the gripping portion at the tip (the gripping portion is expanded by, for example, its own elastic restoring force) In this publication, when the operating wire is pulled back to the hand side by the operating portion, at least a part of the gripping portion is pulled into the coil sheath, whereby the gripping portion is pressed by the inner surface of the coil sheath, When the diameter starts to shrink (the gripping portion starts to close) and the operation wire is pushed forward by the operation portion, the gripping portion protruding from the coil sheath starts to expand due to its own spreading habit (for example, elastic restoring force). .
[0005]
Therefore, when collecting the foreign substance in the body using the spread-type grasping forceps having such a configuration, first, the foreign substance is taken into the inside of the grasped part that is expanded from the tip of the coil sheath. Next, in this state, the operating wire is pulled toward the hand side to reduce the diameter of the gripping portion and grip the foreign matter by the gripping portion. If the entire expandable grasping forceps is taken out of the body in the gripped state, the foreign matter can be collected outside the body.
[0006]
[Problems to be solved by the invention]
By the way, as described above, the gripping portion of the expandable gripping forceps is configured such that the portion protruding from the sheath attempts to expand by its own elastic restoring force, for example, so that the force accompanying the expansion is controlled by some means. Otherwise, when the operation force of the operation unit is released, the operation wire is pushed out by the elastic restoring force of the holding unit, and the holding unit may be unintentionally expanded. In particular, in the expansion by the elastic restoring force, the gripping portion expands when the gripping portion elastically presses against the inner edge of the sheath tip and the gripping portion attempts to come out from the tip of the sheath in the axial direction. When the gripper is in the most closed state (the gripping part is most retracted into the sheath), the gripping part expanding force acting on the inner edge of the sheath tip is the largest, and the operation wire is pushed out in the axial direction. The power to try is the greatest. Therefore, when the operation force by the operation unit is released in the state where the grip unit is most closed, the grip unit is easily unintentionally expanded.
[0007]
However, if the grip part is inadvertently expanded, several problems occur during the procedure. For example, when the expandable grasping forceps are inserted into the treatment instrument insertion channel of the endoscope with the operation wire pulled to the proximal side and the grasping portion closed, the closed grasping portion unintentionally expands. If it is opened, there is a possibility that the spread gripping part may come into sliding contact with the inner surface of the treatment instrument insertion channel of the endoscope and damage the inner surface. In addition, even when the grasping portion of the expandable grasping forceps is introduced into the body through the treatment instrument insertion channel of the endoscope, it is difficult to operate if the grasping portion is inadvertently expanded. It is necessary to hold the part firmly, and the burden on the operator during the operation is increased.
[0008]
In view of the above, in the case of the spread-type grasping forceps that expands by its own spreading habit, when the operating force of the operation unit is released so as not to cause the above-described situation, the gripping unit is particularly closed. It is important not to inadvertently expand the gripping part when it is in a closed state.
[0009]
The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide an expandable grasping forceps with good operability in which the grasping portion does not unintentionally expand.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, an expandable grasping forceps of the present invention includes a flexible sheath that can be inserted into a body, an operation wire that is inserted into the sheath so as to be able to advance and retreat, and a proximal side of the sheath. An operating portion for pushing and pulling the operating wire, and a tip of the operating wire Connected to As the operation wire is pushed and pulled by the operation unit, the operation wire protrudes and retracts from the sheath. Said A gripping part where the part protruding from the sheath opens by its spreading habit, By restricting the advancing and retreating operation of the operation wire by a frictional force with the sheath inner surface provided at a connection portion that connects the grip portion to the distal end of the operation wire A frictional force imparting means for preventing the gripping portion from being inadvertently expanded, and the spreading force exerted by pressing the gripping portion against the inner edge of the sheath when the gripping portion tries to open due to its spreading habit F, where F is an axial force that attempts to move the operation wire in the axial direction by the expanding force F, and Fb is a force that restricts the movement of the operation wire in the axial direction. A frictional force is applied to the operation wire so that a force relationship of Fa <Fb is always maintained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
1 to 8 show a first embodiment of the present invention. The expandable grasping forceps of the present embodiment are provided on an insertion portion 2 (see FIGS. 1 and 2) that can be introduced into the body via a treatment instrument insertion channel of an endoscope, for example, and on the proximal side of the insertion portion 2. And the operation unit 4 (see FIGS. 3 and 4).
[0013]
As shown in FIGS. 1 and 2, the insertion portion 2 includes a sheath 8 having flexibility. The operation wire 12 is inserted into the sheath 8 so as to be able to advance and retreat directly without passing through another member. In addition, a grip portion 15 that can project and retract with respect to the sheath 8 is provided at the distal end of the operation wire 12.
[0014]
The sheath 8 is made of Teflon so that the operation wire 12 can be smoothly advanced and retracted in the sheath 8. (Registered trademark) Or polyethylene. Of course, in order to achieve the same purpose, Teflon is applied to the inner surface of the sheath 8 and the outer surface of the operation wire 12. (Registered trademark) A coating may be applied.
[0015]
The gripping portion 15 includes three elastic gripping members 14. Each elastic gripping member 14 is formed of an elastic linear material, and one end thereof is bundled and brazed by the joint pipe 13 and is collectively connected to the distal end of the operation wire 12.
[0016]
The operation wire 12 is guided to the hand side through the sheath 8 and connected to a slider member 9 described later provided in the operation unit 4. Therefore, when the slider member 9 is slid, the operation wire 12 advances and retreats within the sheath 8, and the grip portion 15 provided at the distal end of the operation wire 12 protrudes and retracts from the distal end of the sheath 8.
[0017]
Further, the gripping part 15 is provided with a spreading habit of expanding by its own elastic restoring force. Specifically, the tip end portion of each elastic gripping member 14 is elastically spread by its own elastic restoring force. Therefore, when the operation wire 12 is pushed forward by the slider member 9 of the operation unit 4, each elastic gripping member 14 protruding from the sheath 8 spreads at substantially equal intervals by its own elastic restoring force. In other words, each elastic gripping member 14 elastically pressed against the inner edge 8 a of the distal end of the sheath 8 is pulled out from the distal end of the sheath 8 in the axial direction, so that the gripping portion 15 is expanded. On the other hand, when the operation wire 12 is pulled back to the proximal side by the slider member 9 of the operation unit 4, at least a part of each elastic gripping member 14 that has been expanded is drawn into the sheath 8. As a result, each elastic gripping member 14 is pressed and the diameter of the gripping portion 15 begins to contract (the gripping portion 15 begins to close).
[0018]
In addition, in order to obtain a good gripping property by the gripping portion 15, a circular spiral claw portion 14a that is smoothly bent inward by about one and a half rounds is provided at the tip of each elastic gripping member 14. The tips of the claw portions 14a are formed in a smooth curved surface and are directed inward. Each elastic gripping member 14 has a different length. When the elastic gripping member 14 is accommodated in the distal end side sheath 8 as shown in FIG. The positions of the claw portions 14a protruding from the sheath 8 are not overlapped. At this time, the elastic gripping members 14 are placed at equal intervals in the sheath 8.
[0019]
As shown in FIGS. 3 and 4, the operation unit 4 includes an operation unit main body 19 and a slider member 9 slidably attached to the operation unit main body 19. A ring 19 a for inserting a thumb is formed at the base end of the operation unit main body 19.
[0020]
As clearly shown in FIG. 5, a cylindrical stopper 26 is press-fitted into the proximal end of the sheath 8. The proximal side of the insertion portion 2 including the stopper 26 is disposed in the operation portion main body 19 and is formed in the operation portion main body 19 by pushing the main body lid 22 in the T direction indicated by an arrow in FIG. By fitting the claw portion 28 of the main body lid 22 into the groove 27 formed, the operation portion main body 19 is fixed. With such a configuration, the assembling property of the operation unit main body 19 and the main body lid 22 is improved.
[0021]
The main body cover 22 may be fixed to the operation section main body 19 by sliding the main body cover 22 in the U direction indicated by arrows in FIGS. 3 and 4 while guiding the claw portion 28 into the groove 27. In this case, after the tapered portion 39 of the main body lid 22 gets over the locking portion 40 formed on the operation portion main body 19, the concave portion 41 formed on the main body lid 22 and the locking portion 40 are engaged. If this is done, it is beneficial that the main body lid 22 does not easily come off from the operation unit main body 19.
[0022]
As shown in FIGS. 3, 4, 5, and 6 (b), the proximal end of the operation wire 12 is disposed in an operation pipe 25 having an inner hole. Further, the proximal end portion of the operation pipe 25 is fitted into the side hole 44 of the stopper member 30 and is fixed by screwing by deforming the operation pipe 25 including the operation wire 12 with the screw 31. Thereby, the fixing strength of the operation wire 12 is improved. Further, the proximal end portion of the operation wire 12 including the operation pipe 25, the stopper member 30, and the screw 31 has the stopper member 30 engaged with the concave portion 34 provided in the slider halves 20 and 20 ′ constituting the slider member 9. It is arranged in a form that matches.
[0023]
Further, as shown in FIGS. 3 and 6A and FIG. 6C, the slider half 20, 20 'has a protrusion 36 of the slider half 20' and a recess 35 of the slider half 20. Are joined by ultrasonic welding or the like. In this ultrasonic welding, the slider halves 20 and 20 'are welded to each other by melting the convex portions 32 provided in the slider halves 20 and 20' in two symmetrical directions. In this case, the concave portion 33 is a relief for preventing a gap in the joint portion when the convex portion 32 is melted.
[0024]
Further, the slider halves 20 and 20 'are composed of two parts having the same shape and have a symmetrical shape, so that it is possible to assemble with no directionality and reduce the cost of parts. Further, the relief 37 is a recess for preventing a protrusion to the appearance due to the pin gate process.
[0025]
3, 4, and 5, the operation pipe 25 including the operation wire 12 is interposed between the head portion 26 a of the stopper 26 protruding from the proximal end of the sheath 8 and the operation portion main body 19. An O-ring 50 is interposed as a frictional force applying means that comes into contact with the outer peripheral surface. The O-ring 50 is in contact with the operation pipe 25 and restricts the advance / retreat operation of the operation wire 12, thereby preventing the grip portion 15 provided at the tip of the operation wire 12 from being inadvertently expanded. Specifically, the spreading force exerted by elastically pressing against the inner edge 8a of the distal end of the sheath 8 by the gripping portion 15 (each elastic gripping member 14) being expanded by its elastic restoring force is F, When the axial force that attempts to move the operation wire 12 in the axial direction by the spreading force F is Fa and the force that restricts the movement of the operation wire 12 in the axial direction is Fb, the O-ring 50 is a force that satisfies Fa <Fb. A frictional force is applied to the operation wire 12 so that the relationship is always maintained. More specifically, as shown in FIG. 8, when the operation unit 4 is set up vertically, the force by which the operation wire 12 is pushed out by the weight of the slider 9 is generated between Fc and the operation wire 12 and the sheath 8. When the frictional force is Fd, the relationship of Fa + Fc <Fb + Fd is established.
[0026]
Next, a brief description will be given of a case in which a foreign body is collected endoscopically using the spread-type grasping forceps having the above-described configuration.
[0027]
First, after inserting the insertion portion of the endoscope into the body cavity, the distal end portion of the insertion portion 2 of the expandable grasping forceps is led out from the distal end portion of the endoscope through the treatment instrument insertion channel of the endoscope. Introduce into the body cavity. At the time of introduction into the body cavity, the slider member 9 is pulled toward the proximal side and the operation wire 12 is pulled toward the proximal side, and the grasping portion 15 is introduced into the sheath 8 as shown in FIG. At this time, the claw portion 14 a provided at the distal end of each elastic gripping member 14 protrudes from the distal end of the sheath 8 without being fully accommodated in the sheath 8, but is accommodated inside the outer periphery of the sheath 8.
[0028]
Next, under endoscopic observation, the distal end portion of the insertion portion 2 of the expandable grasping forceps introduced into the body cavity is brought close to the cell tissue or the like to be collected. Thereafter, by moving the slider member 9 forward, the operation wire 12 that responds to the movement of the slider member 9 is pushed forward, causing each elastic gripping member 14 to protrude from the sheath 8, and as shown in FIG. The part 15 is expanded. Then, the expanded grasping portion 15 is guided to the tissue to be collected, and the collected tissue is taken into the grasping portion 15. Next, by pulling the operation wire 12 toward the hand side, the grasping portion 15 is closed, the tissue inside the grasping portion 15 is securely grasped, and the expandable grasping forceps are held together with the endoscope while maintaining this grasping state. If the tissue is taken out of the body cavity, the tissue can be recovered outside the body.
[0029]
As described above, in the present embodiment, as described above, the O-ring 50 applies a frictional force to the operation wire 12 so that the force relationship of Fa <Fb is always maintained. When the expandable grasping forceps are inserted into the treatment instrument insertion channel of the endoscope in the state of introduction, the closed grasping portion 15 is inadvertently expanded when the aforementioned introduction into the body cavity is performed. A situation in which the inner surface of the instrument insertion channel is damaged by the expanded gripping portion 15 can be avoided. Further, even when the grasping portion 15 of the expandable grasping forceps is introduced into the body through the treatment instrument insertion channel of the endoscope, the grasping portion 15 does not unintentionally expand, so that the operation becomes difficult. Therefore, it is not necessary for the operator to always grasp and operate the slider member 9 firmly in order to prevent the grasping portion 15 from being inadvertently expanded. As a result, the burden on the operator during the operation can be reduced (that is, the operability is good).
[0030]
Further, as in this embodiment, if the O-ring 50 applies a frictional force to the operation wire 12 so that the force relationship of Fa <Fb is always maintained, the grip portion 15 is opened during the expansion. It is also very beneficial because it is also prevented.
[0031]
Further, in the present embodiment, the operation wire 12 is inserted through the sheath 8 so as to be able to advance and retract directly without passing through another member. Moreover, the sheath 8 is formed of Teflon, polyethylene, or the like. Therefore, the operation wire 12 can be smoothly advanced and retracted in the sheath 8, and the grip portion 15 can be expanded with a small amount of operation force. This is particularly true when the insertion portion of the endoscope is bent in the body (including the case where the bending portion of the endoscope insertion portion is bent), and accordingly, the endoscope is inserted into the treatment instrument insertion channel. This is useful when the operating wire 12 is pushed forward in the sheath 8 for the expanding operation of the gripping part 15 in a state where the sheath 8 of the expanding-type gripping forceps being inserted is curved. That is, when the operation wire is pushed forward in the sheath in such a bent state, the conventional structure in which the operation wire is slidably contacted with the metal coil sheath over the entire length causes frictional resistance to the operation wire over the entire length. Although it is conceivable that the wire buckles at the bending portion, if the operation wire 12 is directly inserted into the Teflon sheath 8 to ensure smooth operability of the operation wire 12 as in the present embodiment, Buckling can be prevented, and the grip portion 15 can be expanded and operated with a small amount of operation force.
[0032]
Further, such smooth operability of the operation wire 12 is not hindered by the O-ring 50 that is a frictional force applying means. This is because the O-ring 50 is provided only at one position on the operation unit 4 side (the friction resistance is concentrated at one position), and the friction resistance is not applied over the entire length of the operation wire 14. Further, the portion on the operation unit 4 side where the O-ring 50 is disposed is a region that does not relate to the bending portion of the endoscope that is operated to bend. From this point of view, the smooth operability of the operation wire 12 is achieved. Is not lost under any circumstances.
[0033]
In general, in the expansion-type grasping forceps, if the smooth operability of the operation wire 12 is ensured, inadvertent expansion of the grasping portion 15 connected to the operation wire 12 is promoted. Conversely, if a frictional force is applied to the operation wire 14 in order to prevent the gripping part 15 from being inadvertently expanded, the smooth operability of the operation wire 12 cannot be ensured. However, in the present embodiment, as described above, the O-ring 50 as the frictional force applying means is provided only at one position on the operation unit 4 side, and the operation wire 12 is directly inserted into the sheath 8 made of Teflon or the like. By doing so, the mutually conflicting objectives of “preventing inadvertent expansion of the gripping portion” and “smooth operability of the operation wire” are achieved at the same time. That is, in the present embodiment, the O-ring 50 serving as the frictional force applying means is configured to “prevent the careless spread of the gripping portion” and “smooth operability of the operation wire” depending on the frictional force and the arrangement position thereof. It can be said that it is stipulated as a means to satisfy both objectives at the same time.
[0034]
In addition, such a function and effect are such that each claw portion 14a of the gripping portion 15 cannot be accommodated in the sheath 8 and protrudes from the sheath 8, and as a result, the gripping portion 15 is likely to unintentionally expand. This is particularly beneficial in the expandable forceps of the embodiment.
[0035]
FIG. 9 shows a second embodiment of the present invention. As shown in the figure, in the present embodiment, the frictional force applying means comprises a short metal pipe 70 provided at the tip of the sheath 8. The metal pipe 70 is in contact with the operation wire 12 or the gripping part 15 to restrict the forward / backward movement of the operation wire 12 or the gripping part 15, so that the gripping part 15 provided at the tip of the operation wire 12 is inadvertently expanded. Prevent opening. Of course, in this case as well, the expanding force exerted by elastically pressing the inner edge 8a of the distal end of the sheath 8 by the gripping portion 15 (each elastic gripping member 14) being expanded by its elastic restoring force is F, When the axial force for moving the operation wire 12 in the axial direction by the expanding force F is Fa and the force for restricting the movement of the operation wire 12 in the axial direction is Fb, the metal pipe 70 satisfies Fa <Fb. A frictional force is applied to the operation wire 12 so that the force relationship is always maintained. Other configurations are the same as those in the first embodiment.
[0036]
Therefore, in this embodiment, the same effects as those of the first embodiment can be obtained, and a frictional force is applied to the operation wire 12 or the gripping portion 15 on the distal end side where the gripping portion 15 is provided. Since the advance / retreat operation is regulated, there is an advantage that fine adjustment of the opening degree of the grip portion 15 can be easily performed. Further, since the distal end portion of the sheath 8 on which the metal pipe 70 is disposed is a region that does not participate in the bending portion of the endoscope that is bent, the smooth operability of the operation wire 12 is not impaired.
[0037]
FIG. 10 shows a third embodiment of the present invention. As shown in the drawing, in this embodiment, the frictional force applying means includes a connecting pipe 75 such as the joint pipe 13 that connects the operation wire 12 and the gripping portion 15, and the outer diameter of the connecting pipe 75 is set to the inner diameter of the sheath 8. And are set substantially the same. The connection pipe 75 advances and retreats as the operation wire 12 advances and retracts, and slides on the sheath 8 to restrict the operation wire 12 from moving back and forth, so that the grip portion 15 provided at the distal end of the operation wire 12 is not attached. It is prevented from spreading in advance (a frictional force is applied to the operation wire 12 so that a force relationship of Fa <Fb is always maintained). Other configurations are the same as those of the second embodiment.
[0038]
Therefore, also in this embodiment, it is possible to obtain the same function and effect as those of the second embodiment.
[0039]
FIG. 11 shows a fourth embodiment of the present invention. As shown in the figure, in the present embodiment, the frictional force applying means includes an O-ring 80 interposed between the joint pipe 13 and the sheath 8. The O-ring 80 advances and retreats as the operation wire 12 advances and retreats. The O-ring 80 slides on the sheath 8 to regulate the advance and retreat operation of the operation wire 12, so that the grip portion 15 provided at the distal end of the operation wire 12 does not move. It is prevented from spreading in advance (a frictional force is applied to the operation wire 12 so that a force relationship of Fa <Fb is always maintained). Other configurations are the same as those of the second embodiment.
[0040]
Therefore, also in this embodiment, it is possible to obtain the same function and effect as those of the second embodiment.
[0041]
FIG. 12 shows a fifth embodiment of the present invention. As shown in the figure, in this embodiment, the frictional force imparting means comprises a sliding resistance portion 18a in which the inner diameter of the distal end opening of the sheath 8 is set to be small by processing the distal end of the sheath 8 thinly by thermoforming. The sliding resistance portion 18a slides into contact with the operation wire 12 or the grip portion 15 to restrict the forward / backward movement of the operation wire 12 or the grip portion 15, so that the grip portion 15 provided at the distal end of the operation wire 12 is not prepared. To prevent the spread.
[0042]
By the way, at the time of transportation of the above-described spread-type grasping forceps, the grasping portion 15 may slightly protrude due to vibration or the like, and may be inserted into the endoscope as it is without being noticed by the user. Conceivable. In such a case, there is a possibility that the treatment instrument insertion channel of the endoscope may be damaged or stuck in the treatment instrument insertion channel of the endoscope by the grip portion protruding from the sheath 8.
[0043]
Therefore, a protective cap that can prevent such a situation in advance will be described below.
[0044]
As shown in FIG. 13, the protective cap 90 is detachably attached to the distal end of the sheath 8, and the inner diameter thereof is larger than the outer diameter of the sheath 8, and the entire length thereof is larger than the entire length of the grip portion 15. It is characterized by a long time.
[0045]
When transporting and storing the expandable grasping forceps, the protective cap 90 is attached to the distal end of the sheath 8 with the gripping portion 15 protruding into the protective cap 90 as shown in FIG. In addition, when using the expandable gripping forceps, as shown in FIG. 13B, when the protective cap 90 is removed from the distal end of the sheath 8, the gripping portion 15 opens widely, so that the user can The expanded state can be easily recognized, and the opened gripping part 15 can be reliably pulled into the sheath 8 (see FIG. 13C). Therefore, it is possible to prevent a situation in which the grip portion 15 is inserted into the endoscope with protruding.
[0046]
Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the present invention is applied to a tripod-type grasping forceps. However, the present invention can be applied to all grasping forceps that the grasping portion opens due to its spread habit. Further, the frictional force applying means is not limited to the O-ring. Any form may be used as long as a frictional force can be applied to the operation wire so that a force relationship of Fa <Fb is always maintained. Further, in the above-described embodiment, the “state in which the gripping portion is most closed” defining Fb may include a state in which the gripping portion is completely submerged in the sheath.
[0047]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an expandable gripping forceps with good operability that prevents the gripping part from being unintentionally expanded.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an insertion portion distal end (a state where a gripping portion is expanded) of an expandable gripping forceps according to a first embodiment of the present invention.
2A is a cross-sectional view of the distal end of the insertion portion of the expandable gripping forceps of FIG. 1 (the grip portion is closed), FIG. 2B is a front view of the distal end of the insertion portion of FIG. These are sectional drawings which follow the AA line of (a).
FIG. 3 is a cross-sectional view of an operation unit of the expandable grasping forceps according to the first embodiment of the present invention.
4 is a cross-sectional view taken along line BB in FIG.
FIG. 5 is an enlarged cross-sectional view of an operation wire and its accompanying components.
6A is a cross-sectional view taken along line GG in FIG. 3, FIG. 6B is a cross-sectional view taken along line H-H in FIG. 3, and FIG. 6C is a cross-sectional view taken along line II in FIG. FIG.
7A is a cross-sectional view taken along line CC in FIGS. 3 and 4, FIG. 7B is a cross-sectional view taken along line DD in FIGS. 3 and 4, and FIG. 4 is a cross-sectional view taken along line E-E in FIG. 4, and FIG. 4D is a cross-sectional view taken along line F-F in FIGS. 3 and 4.
FIG. 8 is a schematic diagram showing a force relationship associated with frictional force applying means.
FIG. 9 is a cross-sectional view of a main part of an expandable grasping forceps according to a second embodiment of the present invention.
FIG. 10 is a cross-sectional view of a main part of an expandable grasping forceps according to a third embodiment of the present invention.
FIG. 11 is a cross-sectional view of a main part of an expandable grasping forceps according to a fourth embodiment of the present invention.
FIG. 12 is a cross-sectional view of a main part of an expandable grasping forceps according to a fifth embodiment of the present invention.
FIG. 13 is a schematic view of a protective cap.
[Explanation of symbols]
2 ... Insertion section
4 ... Operation part
12 ... Operation wire
15 ... gripping part
50 ... O-ring (frictional force applying means)
70: Metal pipe (frictional force applying means)
75. Connecting pipe (friction force applying means)
80 ... O-ring (friction force applying means)

Claims (3)

A flexible sheath that can be inserted into the body;
An operation wire inserted in the sheath so as to be able to advance and retreat;
An operating portion provided on the proximal side of the sheath and for pushing and pulling the operating wire;
Is connected to the distal end of said operating wire, as well as project and retract from the sheath by the operation wire is pushed or pulled by the operating unit, and a grip portion portion which projects from the sheath is opened by the spreading behavior,
It is provided at a connection part that connects the grip part to the tip of the operation wire, and the grip part is unintentionally expanded by restricting the advance / retreat operation of the operation wire by a frictional force with the inner surface of the sheath. Frictional force imparting means for preventing,
With
When the gripping part tries to open by its spreading habit, the spreading force exerted by pressing against the inner edge of the distal end of the sheath is F, and the spreading wire F tries to move the operation wire in the axial direction. When the axial force is Fa and the force that restricts the movement of the operation wire in the axial direction is Fb, the frictional force applying means applies the friction force to the operation wire so that the force relationship of Fa <Fb is always maintained. An open-type grasping forceps characterized by being applied. The said frictional force provision means controls the advance / retreat operation | movement of the said operation wire with the frictional force between the connection pipe | tube which connects the said holding part to the front-end | tip of the said operation wire, and the said sheath. Expandable grasping forceps. The frictional force imparting means regulates the advancing / retreating operation of the operation wire by a frictional force between an O-ring provided on a joint pipe connecting the gripping portion to a distal end of the operation wire and the sheath. The expandable grasping forceps according to claim 1.

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