JP2004097624A - Expansion type griping forceps - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide expansion type gripping forceps which have a good operability without letting a gripping section expand unexpectedly. <P>SOLUTION: The expansion type gripping forceps of the present invention are equipped with a frictional force imparting means 50 for preventing the gripping section 15 provided on a distal end side of an operation wire 12 from expanding unexpectedly, by regulating advance and retreat movements of the operation wire 12 by the frictional force. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expanding gripping forceps for gripping an object by expanding a gripping portion at a distal end in order to perform various sampling procedures such as polyp collection and biopsy in a body.
[0002]
[Prior art]
For example, grasping forceps which are introduced into a body through a treatment instrument insertion channel of an endoscope, grasp and collect foreign matter in the body, or are used to collect a test cell tissue or the like have conventionally been various. Kinds are known.
[0003]
Such a grasping forceps is provided, for example, at an insertion portion made of a metal coil sheath whose outer periphery is covered with a skin tube, an operation wire inserted into the insertion portion so as to be able to advance and retreat, and provided near the insertion portion. And an operation unit for pushing and pulling the operation wire, and a grip unit provided on a distal end side of the operation wire, and the operation wire pushes and pulls the operation wire to operate the operation wire. Are opened and closed so that foreign substances can be gripped by the gripping part.
[0004]
In addition, various types of means for opening and closing the grip portion at the distal end by pushing and pulling the operation wire are conventionally known. For example, an expanding gripping forceps (for example, Japanese Unexamined Utility Model Publication No. 5-9517 or Japanese Patent Application Laid-Open No. 8-98839) in which the gripping portion at the tip is provided with an expanding behavior (the gripping portion expands by its own elastic restoring force) In the related art, when the operating wire is pulled back by the operating unit, 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, and When the diameter starts to shrink (the gripping part starts to close) and the operating wire is pushed forward by the operating part, the gripping part protruding from the coil sheath starts to expand due to its own expanding behavior (for example, elastic restoring force). .
[0005]
Therefore, when collecting foreign matter in the body by using the expandable grasping forceps having such a configuration, first, the foreign matter is taken into the inside of the grasped portion that has been expanded by projecting from the distal end of the coil sheath. Next, in this state, by pulling in the operation wire toward the hand side, the diameter of the grip portion is reduced, and the foreign material is gripped by the grip portion. Then, by taking out the entire expanding type grasping forceps outside the body in the grasping 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 controls the force accompanying this expansion by some means because the portion projecting from the sheath attempts to expand by its own elastic restoring force, for example. Otherwise, when the operation force of the operation unit is released, the operation wire may be pushed out by the elastic restoring force of the grip unit, and the grip unit may be inadvertently expanded. In particular, in the expansion by the elastic restoring force, the gripping portion elastically presses against the inner edge of the distal end of the sheath and the gripping portion attempts to escape from the distal end of the sheath in the axial direction. When the portion is in the most closed state (the state in which the grip portion is drawn most into the sheath), the expanding force of the grip portion acting on the inner edge of the distal end of the sheath becomes the largest, and the operation wire is pushed out in the axial direction. The greatest effort is required. Therefore, when the operating force of the operation unit is released in a state in which the grip portion is most closed, the grip portion is easily inadvertently expanded.
[0007]
However, inadvertent expansion of the grips causes some problems during the procedure. For example, when inserting the expandable grasping forceps into the treatment instrument insertion channel of the endoscope while pulling the operation wire toward the hand and closing the grasping section, the closed grasping section is inadvertently expanded. When opened, the expanded gripper may slide on the inner surface of the treatment tool insertion channel of the endoscope and damage the inner surface. Further, even when the grasping portion of the expandable grasping forceps is introduced into the body through the treatment instrument insertion channel of the endoscope, if the grasping portion is inadvertently expanded, it is difficult to operate the grasping forceps. The part must be firmly grasped, and the burden on the operator during the operation increases.
[0008]
From the above, in the case of the expandable grasping forceps that expands by its own expanding behavior, when the operating force of the operation unit is released so as not to cause the above-described situation, particularly, the grasping unit is closed. It is important not to inadvertently open the gripping part in the closed state.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an expandable gripping forceps with good operability in which a gripper is not inadvertently expanded.
[0010]
[Means for Solving the Problems]
In order to solve the above problem, an expanding gripping forceps according to the present invention includes a flexible sheath that can be inserted into a body, an operation wire that is inserted into and retracted from the sheath, and a proximal side of the sheath. And an operation unit for pushing and pulling the operation wire, and provided on the distal end side of the operation wire, wherein the operation wire pushes and pulls the operation wire to protrude and retract from the sheath. The gripping portion that protrudes from the sheath due to its expanding behavior and the gripping portion provided on the distal end side of the operating wire are inadvertently expanded by regulating the advancing and retreating operation of the operating wire by frictional force. And a frictional force applying means for preventing the force from spreading, and the expanding force exerted by pressing the inner edge of the distal end of the sheath by the gripping portion trying to open due to its expanding behavior is F, Assuming that the axial force for moving the operation wire in the axial direction by the expanding force F is Fa and the force for restricting the movement of the operation wire in the axial direction is Fb, the frictional force applying means is expressed as Fa <Fb. A frictional force is applied to the operation wire so that the following force relationship is always maintained.
[0011]
BEST MODE FOR CARRYING OUT 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 is provided on an insertion portion 2 (see FIGS. 1 and 2) which can be introduced into a body via a treatment tool insertion channel of an endoscope, for example, and is provided near the insertion portion 2. Operating section 4 (see FIGS. 3 and 4).
[0013]
As shown in FIGS. 1 and 2, the insertion section 2 includes a flexible sheath 8. The operation wire 12 is inserted into the sheath 8 so as to be able to advance and retreat directly without any intervening other members. In addition, a grip portion 15 that can protrude and retract from the sheath 8 is provided at a distal end of the operation wire 12.
[0014]
The sheath 8 is made of Teflon, polyethylene, or the like so that the operation wire 12 can be smoothly advanced and retracted in the sheath 8. Of course, in order to achieve the same purpose, a Teflon coating may be applied to the inner surface of the sheath 8 or the outer surface of the operation wire 12.
[0015]
The holding part 15 is composed of three elastic holding members 14. Each elastic gripping member 14 is formed of an elastic linear material, one end of which is bundled and brazed by a joint pipe 13 and is connected to the distal end of the operation wire 12 at a time.
[0016]
The operation wire 12 is guided to the near side through the sheath 8, and is connected to a slider member 9 provided in the operation unit 4, which will be described later. Therefore, when the slider member 9 is slid, the operation wire 12 advances and retreats in the sheath 8, and the grip 15 provided at the distal end of the operation wire 12 projects and retracts from the distal end of the sheath 8.
[0017]
In addition, the gripping portion 15 is provided with an expanding behavior that expands by its own elastic restoring force. Specifically, the distal end portion of each elastic gripping member 14 is elastically expanded by its own elastic restoring force. Therefore, when the operation wire 12 is pushed forward by the slider member 9 of the operation section 4, the elastic holding members 14 protruding from the sheath 8 spread at substantially equal intervals due to their own elastic restoring force. That is, each elastic gripping member 14 elastically pressed against the inner edge 8a at the distal end of the sheath 8 comes off the distal end of the sheath 8 in the axial direction, so that the gripping portion 15 expands. On the other hand, when the operation wire 12 is pulled back by the slider member 9 of the operation unit 4, at least a part of each of the expanded elastic gripping members 14 is drawn into the sheath 8, and thereby the inner surface of the sheath 8 is formed. As a result, each elastic gripping member 14 is pressed, and the diameter of the gripping portion 15 starts to contract (the gripping portion 15 starts to close).
[0018]
In addition, in order to obtain a good gripping property by the gripping portion 15, a circular spiral claw portion 14a which is smoothly bent about one and a half turns inside is provided at an end of each elastic gripping member 14. The tips of the claws 14a are formed into a smooth curved surface and face inward. Each elastic gripping member 14 has a different length. When the elastic gripping member 14 is accommodated in the distal sheath 8 as shown in FIG. The positions of the claws 14a protruding from the sheath 8 without overlapping are not overlapped. At this time, the elastic gripping members 14 are located at equal intervals within the sheath 8.
[0019]
As shown in FIGS. 3 and 4, the operation section 4 includes an operation section main body 19 and a slider member 9 slidably attached to the operation section main body 19. A ring 19 a for inserting a thumb is formed at the base end of the operation section 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 section 2 including the stopper 26 is disposed in the operation section main body 19, and is formed on the operation section main body 19 by pushing the main body cover 22 in the T direction indicated by the arrow in FIG. By fitting the claw portion 28 of the main body cover 22 into the groove 27 thus formed, it is fixed to the operation portion main body 19. With such a configuration, the assemblability of the operation unit main body 19 and the main body cover 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 an arrow 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 cover 22 passes over the locking portion 40 formed on the operation portion main body 19, the concave portion 41 formed on the main body cover 22 and the locking portion 40 are engaged. This is useful because the main body lid 22 is unlikely to come off the operation section 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. The proximal end 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 of the operation wire 12 including the operation pipe 25, the stopper member 30, and the screw 31 is connected to the recess 34 provided in the slider halves 20, 20 ′ constituting the slider member 9 by the stopper member 30. They are arranged in such a way that they match.
[0023]
Also, as shown in FIGS. 3, 6A and 6C, the slider halves 20 and 20 'have protrusions 36 of the slider halves 20' and recesses 35 of the slider halves 20. And joined by ultrasonic welding or the like. In this ultrasonic welding, the two slider halves 20, 20 'are welded and joined by melting the two convex portions 32 symmetrically provided on the slider halves 20, 20', respectively. In this case, the concave portion 33 is an escape white because a gap is not formed in the joint portion when the convex portion 32 is melted.
[0024]
Further, the slider halves 20, 20 'are composed of two parts having the same shape and have a symmetrical shape, so that it is possible to assemble without a direction and to reduce the cost of parts. Further, the escape 37 is a depression for preventing a protrusion to the external appearance due to the pin gate processing.
[0025]
As shown in FIGS. 3, 4, and 5, the operation pipe 25 including the operation wire 12 is provided between the operation section main body 19 and the head 26 a of the stopper 26 protruding from the proximal end of the sheath 8. An O-ring 50 is inserted as a frictional force applying means in contact with the outer peripheral surface. The O-ring 50 contacts the operation pipe 25 to restrict the advancing and retreating operation of the operation wire 12, thereby preventing the grip portion 15 provided at the distal end of the operation wire 12 from being inadvertently expanded. Specifically, the gripping portion 15 (each elastic gripping member 14) elastically presses against the inner edge 8a of the distal end of the sheath 8 when the gripping portion 15 (the respective elastic gripping members 14) attempts to expand by the elastic restoring force, and the expanding force is F, Assuming that 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 O-ring 50 has a force of 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 upright, a force for pushing out the operation wire 12 by its own weight of the slider 9 is generated between the operation wire 12 and the sheath 8. Assuming that 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 in the body is collected endoscopically using the expandable grasping forceps having the above 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 tool insertion channel of the endoscope. Introduce into body cavity. At the time of introduction into the body cavity, the operation member 12 is pulled toward the hand by pulling the slider member 9 toward the hand, and the grip 15 is brought into the sheath 8 in a closed state as shown in FIG. At this time, the claw portion 14 a provided at the distal end of each elastic gripping member 14 cannot be accommodated in the sheath 8 and protrudes from the distal end of the sheath 8, but is accommodated inside the outer periphery of the sheath 8.
[0028]
Next, under endoscopic observation, the distal end 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 responsive to the movement of the slider member 9 is pushed forward to cause each elastic gripping member 14 to protrude from the sheath 8, and as shown in FIG. The part 15 is expanded. Then, the expanded grip portion 15 is guided to the tissue to be collected, and the collected tissue is taken into the grip portion 15. Then, by pulling the operation wire 12 toward the hand, the grip portion 15 is closed, the tissue inside the grip portion 15 is securely gripped, and the expandable grip forceps together with the endoscope is held while maintaining this grip state. If the tissue is taken out of the body cavity, the tissue can be collected outside the body.
[0029]
As described above, in the present embodiment, as described above, since the O-ring 50 applies the frictional force to the operation wire 12 so that the force relationship of Fa <Fb is always maintained, the grip portion 15 is closed. When the expanding gripping forceps is inserted into the treatment instrument insertion channel of the endoscope in the above-described state, the closed gripping portion 15 is inadvertently expanded at the time of introduction into the body cavity and the treatment of the endoscope is performed. A situation in which the inner surface of the tool insertion channel is damaged by the expanded grip 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 inadvertently expand, so that operation becomes difficult. Therefore, there is no need for the surgeon to always hold and operate the slider member 9 firmly to prevent inadvertent expansion of the grip portion 15. As a result, the burden on the operator during the operation can be reduced (that is, the operability is good).
[0030]
Also, as in the present 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 gripping portion 15 opens during the expansion. Is also very beneficial.
[0031]
Further, in the present embodiment, 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. Moreover, the sheath 8 is made of Teflon, polyethylene, or the like. Therefore, the advancing and retreating operation of the operation wire 12 can be performed smoothly within the sheath 8, and the operation of expanding the grip portion 15 can be performed with a small amount of operation force. This particularly indicates that the insertion portion of the endoscope is bent in the body (including the case where the bending portion of the insertion portion of the endoscope is operated to bend), and accordingly, the treatment instrument insertion channel of the endoscope becomes This is advantageous when the operation wire 12 is pushed forward in the sheath 8 for the operation of expanding the grip portion 15 in a state where the sheath 8 of the expanding gripping forceps inserted is curved. In other words, when the operation wire is pushed forward in the sheath in such a curved state, the conventional structure in which the operation wire slides on the metal coil sheath over the entire length applies frictional resistance to the operation wire over the entire length. It is conceivable that the wire buckles at the curved portion. However, if the operation wire 12 is inserted directly into the Teflon sheath 8 to ensure smooth operability of the operation wire 12 as in the present embodiment, such a case is possible. Buckling can be prevented, and the grip portion 15 can be opened 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 as the frictional force applying means. This is because the O-ring 50 is provided only at one location on the operation section 4 side (concentrating frictional resistance at one location), and does not apply frictional resistance over the entire length of the operation wire 14. The portion on the operation unit 4 side where the O-ring 50 is provided is a region that is not involved in the bending portion of the endoscope that is operated to be bent. Is not lost under any circumstances.
[0033]
In general, in the expanding type grasping forceps, if smooth operability of the operation wire 12 is secured, careless 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 grip portion 15 from being inadvertently expanded, 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 inserted directly into the sheath 8 made of Teflon or the like. By doing so, the mutually contradictory objectives of "preventing careless expansion of the grip portion" and "smooth operability of the operation wire" are simultaneously achieved. In other words, in the present embodiment, the O-ring 50 as the frictional force applying means can prevent “inadvertent opening of the gripping portion” and “smooth operability of the operation wire” depending on the frictional force and its disposition position. It can be said that it is defined as a means that simultaneously fulfills both purposes.
[0034]
In addition, such an effect is obtained because each claw portion 14a of the grip 15 protrudes from the sheath 8 without being accommodated in the sheath 8, and as a result, the grip 15 is likely to be inadvertently expanded. It is particularly advantageous in the expanding forceps of the embodiment.
[0035]
FIG. 9 shows a second embodiment of the present invention. As shown, in the present embodiment, the frictional force applying means comprises a short metal pipe 70 provided at the distal end of the sheath 8. The metal pipe 70 comes into contact with the operation wire 12 or the grip portion 15 to restrict the advance / retreat operation 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 inadvertently expanded. Prevent it from opening. Of course, also in this case, the expanding force exerted by the gripping portion 15 (each elastic gripping member 14) elastically pressing against the inner edge 8a of the distal end of the sheath 8 by the elastic restoring force is F, If 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 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. The other configuration is the same as that of the first embodiment.
[0036]
Therefore, also in the present embodiment, the same operation and effect as those of the first embodiment can be obtained, and in particular, a frictional force is applied to the operation wire 12 or the grip portion 15 on the distal end side where the grip portion 15 is provided. Since the forward / backward movement is restricted, there is an advantage that the fine adjustment of the opening degree of the grip 15 can be easily performed. Further, since the distal end of the sheath 8 where the metal pipe 70 is disposed is a region that does not participate in the bending portion of the endoscope that is operated to be bent, 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 the present embodiment, the frictional force applying means includes a connecting pipe 75 such as a connecting pipe 13 for connecting the operation wire 12 and the grip portion 15, and the outer diameter of the connecting pipe 75 is changed to the inner diameter of the sheath 8. It is formed by setting substantially the same as. The connection tube 75 advances and retreats with the advance and retreat operation of the operation wire 12, and slides into contact with the sheath 8 to regulate the advance and retreat operation of the operation wire 12, so that the grip 15 provided at the distal end of the operation wire 12 is improper It is prevented from being easily expanded (a frictional force is applied to the operation wire 12 so that the force relationship of Fa <Fb is always maintained). The other configuration is the same as that of the second embodiment.
[0038]
Therefore, also in the present embodiment, the same operation and effect as in the second embodiment can be obtained.
[0039]
FIG. 11 shows a fourth embodiment of the present invention. As shown, in the present embodiment, the frictional force applying means includes an O-ring 80 inserted between the joint pipe 13 and the sheath 8. The O-ring 80 moves forward and backward with the movement of the operation wire 12, and slides into contact with the sheath 8 to regulate the movement of the operation wire 12. It is prevented from being easily expanded (a frictional force is applied to the operation wire 12 so that the force relationship of Fa <Fb is always maintained). The other configuration is the same as that of the second embodiment.
[0040]
Therefore, also in the present embodiment, the same operation and effect as in the second embodiment can be obtained.
[0041]
FIG. 12 shows a fifth embodiment of the present invention. As shown in the figure, in the present embodiment, the frictional force applying means comprises a sliding resistance portion 18a in which the distal end of the sheath 8 is thinned by thermoforming so that the inner diameter of the distal end opening of the sheath 8 is set small. The sliding resistance portion 18a slides on the operation wire 12 or the grip portion 15 to restrict the advance / retreat operation 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 inadvertent. To prevent it from expanding.
[0042]
By the way, during the transportation of the expanding gripping forceps described above, the gripping portion 15 may slightly jump out of the sheath 8 due to vibration or the like, and the user may insert the gripping force into the endoscope without noticing. Conceivable. In such a case, there is a possibility that the grasping portion protruding from the sheath 8 may damage the treatment tool insertion channel of the endoscope, or may be stuck in the treatment instrument insertion channel of the endoscope.
[0043]
Therefore, a protection cap that can prevent such a situation 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, the inner diameter is larger than the outer diameter of the sheath 8, and the entire length is larger than the entire length of the grip portion 15. It is characterized by being long.
[0045]
When transporting and storing the expanding gripping forceps, as shown in FIG. 13A, the protection cap 90 is attached to the distal end of the sheath 8 with the gripping portion 15 protruding into the protection cap 90. Further, when using the expanding 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 is greatly opened. The expanded state can be easily recognized, and the opened grip portion 15 can be reliably pulled into the sheath 8 (see FIG. 13C). Therefore, it is possible to prevent a situation in which the gripper 15 is inserted into the endoscope while protruding.
[0046]
It is needless to say that the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof. For example, in the above-described embodiment, the present invention is applied to a tripod-type gripping forceps, but the present invention can be applied to all gripping forceps in which a gripping portion is opened due to its expanding behavior. 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 the force relationship of Fa <Fb is always maintained. Further, in the above-described embodiment, the “state in which the grip portion is most closed” that defines Fb may include a state in which the grip portion is completely immersed in the sheath.
[0047]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an expanding gripping forceps with good operability in which the gripping portion is not inadvertently expanded.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a distal end of an insertion portion (in a state where a grip portion is expanded) of an expandable grip forceps according to a first embodiment of the present invention.
2A is a cross-sectional view of the distal end of the insertion portion (in a state in which the grip portion is closed) of the expandable gripping forceps of FIG. 1, FIG. 2B is a front view of the distal end of the insertion portion of FIG. FIG. 2 is a cross-sectional view taken along line AA in FIG.
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.
FIG. 4 is a sectional view taken along line BB of FIG. 3;
FIG. 5 is an enlarged cross-sectional view of the operation wire and its accompanying components.
6A is a sectional view taken along line GG of FIG. 3, FIG. 6B is a sectional view taken along line HH of FIG. 3, and FIG. 6C is a section taken along line II of FIG. FIG.
7A is a sectional view taken along line CC of FIGS. 3 and 4, FIG. 7B is a sectional view taken along line DD of FIGS. 3 and 4, and FIG. 4 is a cross-sectional view taken along line EE, and FIG. 4D is a cross-sectional view taken along line FF in FIGS. 3 and 4.
FIG. 8 is a schematic diagram showing a force relationship associated with a frictional force applying unit.
FIG. 9 is a sectional view of a main part of an expanding gripping forceps according to a second embodiment of the present invention.
FIG. 10 is a sectional view of a main part of an expanding gripping forceps according to a third embodiment of the present invention.
FIG. 11 is a sectional view of a main part of an expanding gripping forceps according to a fourth embodiment of the present invention.
FIG. 12 is a sectional view of a main part of an expanding gripping 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 part
4 ... Operation unit
12 ... Operation wire
15 ... gripping part
50 O-ring (frictional force applying means)
70 metal pipe (frictional force applying means)
75 ... connecting pipe (frictional force applying means)
80 O-ring (frictional 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 operation unit provided on the proximal side of the sheath and for pushing and pulling the operation wire;
A grip portion provided on the distal end side of the operation wire, projects and retracts from the sheath when the operation wire is pushed and pulled by the operation portion, and a portion that protrudes from the sheath opens due to its expanding behavior.
A frictional force applying unit that restricts the gripping portion provided on the distal end side of the operation wire from being inadvertently expanded by regulating the forward / backward movement of the operation wire by a frictional force,
With
When the gripping portion tries to open due to its expanding behavior, the expanding force applied to the inner edge of the distal end of the sheath is F, and the operating wire is moved in the axial direction by the expanding force F. Assuming that the axial force is Fa and the force regulating the axial movement of the operation wire is Fb, the frictional force applying means applies the frictional force to the operation wire so that the force relationship of Fa <Fb is always maintained. An expanding gripping forceps to be applied. The expandable grasping forceps according to claim 1, wherein the frictional force applying means is provided on the operation unit. The expandable gripping forceps according to claim 1, wherein the frictional force applying means is provided at a distal end of the sheath.

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