Abstract:
A manipulating part of an endoscopic treatment tool, in which, to a cylindrical member having a first finger retaining member, there is slidably mounted a second finger retaining member slidably for remotely driving a distal end operating part using a sliding movement of the second finger retaining member along the cylindrical member. For the manipulating part, a stopper is added, which is movably provided on the cylindrical member, and which is fixed at an arbitrary position on the cylindrical member. The stopper is designed to restrict a length of the sliding movement of the second finger retaining member.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a manipulating part of an endoscopic treatment tool that is to be inserted into a treatment tool insertion channel of an endoscope. 
     In general, an endoscopic treatment tool is designed such that a distal end operating section is driven with a manipulating part on an operator side through a manipulating wire passed through and axially movable with respect to a sheath inserted into a treatment tool insertion channel of an endoscope. 
     The manipulating part is generally equipped with a first finger retaining member that is attached to a cylindrical member connected to the proximal end of the sheath, and a second finger retaining member that is slidable relative to the cylindrical member and connected to the proximal end of the manipulating wire. The sliding motion of the second finger retaining member along the cylindrical member causes the axial motion of the manipulating wire. 
     In case of some treatment tools, such as an endoscopic forceps tool, which use a closely wound coil as the sheath, the manipulating stroke varies depending on the degree of bending of the sheath. Therefore, during the use of the tool, the manipulating stroke may be too short to perform sufficient operation, or excessively long, causing the buckling of the manipulating wire. 
     In case of a high frequency snare, a basket type grasping tool, etc. in which a plurality of elastically contractible and expandable wires are retracted into or protruded from the distal end of the sheath, the constant size of the expanded elastic wires is inconvenient for an operator to treat a polyp, a foreign matter or the like which has a different size. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a manipulating part of an endoscopic treatment tool, which makes it possible to readily adjust the stroke of a manipulating wire depending on the condition of use. 
     To achieve the above-noted object, the present invention provides a manipulating part of an endoscopic treatment tool, comprising: a shaft member having a first finger retaining member; a second finger retaining member slidably mounted to the shaft member so that a sliding movement of the second finger retaining member along the shaft member drives a distal end operating part remote from the manipulating part; and a stopper movably provided on the shaft member, and fixed at an arbitrary position on the shaft member, the stopper restricting a length of the sliding movement of the second finger retaining member. 
     The stopper may be fixed by a manually-operable screw relative to the shaft member, or the shaft member may be elastically deformed to permit the movement of the stopper relative to the shaft member, while a deformation restricting member may be connected to the second finger retaining member to inhibit the elastic deformation of the shaft member when the second finger retaining member is located close to the stopper. 
     In the latter case, it is preferable that the stopper is annular and surrounds the shaft member, at least one protrusion is provided on an inner circumferential surface of the stopper and a plurality of recesses each for engagement with the protrusion are provided on an outer surface of the shaft member and arranged along the length of the shaft member with intervals. 
     The stopper and the shaft member may be fixed to each other through a ratchet. 
     The shaft member is preferably in the form of a cylindrical member. 
     The present disclosure relates to the subject matter contained in Japanese patent application No. Hei. 10-146808 (filed on May 28, 1998), which is expressly incorporated herein by reference in its entirety. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is a sectional plan view showing a manipulating part of an endoscopic treatment tool according to a first embodiment of the present invention; 
     FIG. 2 is a plan view showing the entire construction of the endoscopic treatment tool according to the first embodiment; 
     FIG. 3 is an enlarged, sectional side view showing a portion of the manipulating part of the endoscopic treatment tool according to the first embodiment; 
     FIG. 4 is a sectional view taken along line IV—IV of FIG. 3; 
     FIG. 5 is a sectional plan view showing a manipulating part of an endoscopic treatment tool according to a second embodiment of the present invention; 
     FIG. 6 is a sectional view taken along line VI—VI of FIG. 5; 
     FIG. 7 is a sectional plan view showing a state in which a stopper position is being changed in the manipulating part of the endoscopic treatment tool according to the second embodiment; 
     FIG. 8 is a sectional plan view showing a state in which the stopper is in contact with a second finger retaining member in the manipulating part of the endoscopic treatment tool according to the second embodiment; and 
     FIG. 9 is a sectional plan view showing a manipulating part of an endoscopic treatment tool according to a third embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     FIG. 2 shows an endoscopic treatment tool according to a first embodiment of the present invention. As an example of the endoscopic treatment tools to which the present invention is applicable, a basket type grasping tool is illustrated. That is, the present invention is applicable not only to the basket type grasping tool but also to a high frequency snare, a biopsy forceps and other various endoscopic treatment tools. 
     Reference numeral  1  in the drawings denotes a flexible sheath adapted to be removably inserted into a treatment tool insertion channel of an endoscope, which is formed, for instance, of a resin tube made of tetrafluoroethylene. In addition, in case of the biopsy forceps, the sheath  1  is typically formed of a closely wound coiled wire. 
     A manipulating wire  2  is passed through the sheath  1  and axially movable relative thereto. A basket  3  constructed by a plurality of elastic wires is connected to the distal end of the manipulating wire  2  as a distal end operating part. The basket  3  is retracted into and protruded from the distal end of the sheath  1  by axially moving the manipulating wire  2 . 
     The proximal end of the sheath  1  is connected to one end portion of a cylindrical (or rod-like) member  11  of a manipulating part  10  made of plastic material. The other end portion of the cylindrical member  11  is provided with an annular, first finger retaining member  12  for retaining operator&#39;s thumb thereon. 
     A spool-like, second finger retaining member  14  is axially-movably mounted on the cylindrical member  11  so as to receive operator&#39;s forefinger and middle finger thereon. The proximal end of the manipulating wire  2  is fixedly connected to the second finger retaining member  14 . 
     By moving the second finger retaining member  14  along the cylindrical member  11 , the manipulating wire  2  is axially moved within the sheath  1  to thereby expand or contract the basket  3  provided at the distal end. 
     FIG. 1 is a sectional plan view of the manipulating part  10 . The cylindrical member  11  is in the form of a slender circular column having a substantially constant outer diameter over the entire length thereof. A slit  16  having a constant width is formed through the cylindrical member  11  and elongated along the length of the cylindrical member  11 . 
     A wire fixing member  17  is axially slidably disposed within the slit  16 , and fixedly connects the proximal end of the manipulating wire  2  to the second finger retaining member  14 . FIG. 3 is an enlarged sectional side view showing a manner of the connection by the wire fixing member  17 , and FIG. 4 is a sectional view taken along line IV—IV of FIG.  3 . 
     As illustrated, the wire fixing member  17  has a pair of elastically deformable, wire retaining arms  17   a  into which the proximal end  2   a  of the manipulating wire  2  bent to form a lump having a relatively large outer dimension is inserted forcibly, and a pair of elastically deformable, connecting protrusions  17   b  which are inserted into and engaged with respective engagement holes  14   a  formed in the second finger retaining member  14 . 
     With this arrangement, the wire fixing member  17  onto which the proximal end of the manipulating wire  2  is retained is slid along with the second finger retaining member  14  relative to the cylindrical member  11 , and thus the axial motion of the second finger retaining member  14  causes the axial motion of the manipulating wire  2 . 
     As shown in FIG. 1, an annular stopper  20  is fitted on the outer peripheral surface of the cylindrical member  11  and located forwardly of the second finger retaining member  14 . A manually-operable screw  21  is threadingly engaged with a threaded hole formed through the stopper  20 . The screw  21  has a head portion in the form of a knob. The stopper  20  can be moved along the cylindrical member  11  when the screw  21  is loosened, and can be surely fixed at an arbitrary position on the cylindrical member  11  when the screw  21  is tightened. 
     As illustrated in FIG. 2, a range or distance A where the second finger retaining member  14  is movable is defined at a rear end side by the rear end of the slit  16  and at a front end side by the stopper  20 . Accordingly, the stroke of the manipulating wire  2  can be readily adjusted to be suitable for the currently required condition of the tool. That is, the stopper  20  can be moved to and fixed at an arbitrary position to define an appropriate stroke of the manipulating wire. 
     FIG. 5 shows a manipulating part  10  according to a second embodiment of the present invention. A structure for retaining the stopper  20  onto the cylindrical member  11  in the second embodiment is different from that in the first embodiment. 
     As illustrated in FIG. 6 showing a cross-section taken along line VI—VI, a semi-spherical protrusion  22  is provided on the inner circumferential surface of the stopper  20  fitted on the cylindrical member  11 . In this embodiment, a pair of semi-spherical protrusions  22  are provided at diametrically opposite positions, respectively. 
     A plurality of recesses (for example, about two to ten recesses)  18  are provided on the outer surface of the cylindrical member  11  along the length of the cylindrical member  11  at predetermined intervals, each for engagement with the protrusions  22  without rattling. Reference numeral  19  designates a guide groove along which the protrusion  22  is passed to be engaged with the recess  18  during assembly. 
     The internal side of the cylindrical member  11  having the recesses  18  are formed with the slit  16  as previously described, and thus the spatial space of the slit  16  facilitates such flexibility of the cylindrical member  11  as shown in FIG. 7 that when a relatively strong axial force is applied to the stopper  20 , the protrusion  22  is disengaged from the recess  18  while elastically deforming the cylindrical member  11  radially inwardly, and the stopper  20  is axially moved to engage the protrusion  22  with desired another recess  18 . 
     Note that since the slit  16  is substantially filled by the wire fixing member  17  and forms a deformation restricting member at a position where the second finger retaining member  14  is fitted on the outside of the cylindrical member  11 , the cylindrical member  11  cannot be deformed to disengage the protrusion  22  of the stopper  20  from the recess  18  when the second finger retaining member  14  is moved forwardly and contacted with the stopper  20 . 
     Therefore, a range or distance where the second finger retaining member  14  is movable forwardly is defined by the stopper  20 . Accordingly, the stroke of the manipulating wire  2  can be readily adjusted to be suitable for the currently required condition of the tool. That is, an appropriate stroke of the manipulating wire can be defined by simply selecting one of the recesses  18  to be engaged with the protrusion  22  of the stopper  20 . 
     FIG. 9 shows an manipulating part  10  according to a third embodiment of the present invention. A structure for retaining the stopper  20  onto the cylindrical member  11  in the third embodiment is different from those in the first and second embodiments. 
     In this embodiment, a plurality of ratchet grooves  19  are formed on the outer circumferential surface of the cylindrical member  11 , whereas a ratchet claw  23  is formed on the stopper  20  for engagement with selected one of the ratchet grooves  19  to inhibit the forward movement of the stopper  20  relative to the cylindrical member  11 . 
     The ratchet claw  23  is mounted on the stopper  20  so as to be rotatable about the axis  24 . Therefore, by pushing the rear end portion of the ratchet claw  23  in a direction indicated by an arrow B, the engagement between the front end portion of the ratchet claw  23  and the ratchet groove  19  can be released. Upon the disengagement of the ratchet claw  23  from the ratchet groove  19  the stopper  20  is moved to an arbitrary position, and then the ratchet claw  23  is again engaged with another ratchet groove  19  at that position to adjust the stroke of the manipulating wire  2 . 
     In addition, the present invention should not be limited to the embodiments described above. The movable stopper  20  may be provided behind the second finger retaining member  14 , or two movable stoppers  20  may be respectively provided forwardly and behind the second finger retaining member  14 . The configuration of the stopper  20  and the structure for engaging/disengaging the stopper  20  with/from the cylindrical member  11  may be modified in any suitable ways. 
     According to the present invention, a stopper for restricting a slidable range in which a second finger retaining member is slidable is provided on a cylindrical member of a manipulating part so that the stopper can be fixed at an arbitrary position. Therefore, a stroke of a manipulating wire can be readily adjusted depending on the condition or situation. That is, it is possible to eliminate the insufficiency or excessiveness of the manipulating stroke which may hinder an appropriate operation or cause the buckling of the manipulating wire. In case of a treatment tool having an expandable and contractible distal end operating part, the stroke can be adjusted to an optimum one appropriate for the size of a polyp, a foreign matter, etc. to ensure the speedy and positive treatment.