a preferred embodiment of the invention will be explained with reference to fig1 to 4 . as shown in fig1 , a forceps for endoscope 1 according to this embodiment comprises an insertion section 2 that is inserted into a body cavity , an openable and closeable forceps section 3 , provided at a tip section 2 a of the insertion section 2 , and an operation section 5 for operating the forceps section 3 . the insertion section 2 is fitted with a tubular seizing member 6 having flexibility around its outer peripheral face , an oscillating operation axis member 7 , which can move forward and backward in the axial direction , and an opening - closing operation axis member 8 , which can move forward and backward in the axial direction together with the oscillating operation axis member 7 , being provided inside the seizing member 6 . the operation section 5 connects to the insertion section 2 , and operates the forceps section 3 by moving the oscillating operation axis member 7 and the opening - closing operation axis member 8 backward and forward in their respective axial directions . the forceps section 3 comprises a first forceps member 10 and a second forceps member 12 , which faces the first forceps member 10 and can rotate with a first pivotal supporting member ( first pivotal support ) 11 as its fulcrum . the first forceps member 10 is formed from an approximately rod - shaped metal piece , and is connected to the tip section 2 a of the insertion section 2 , which it can rotate around with a second pivotal supporting member ( second pivotal support ) 13 at the base 10 a side as its fulcrum ; in addition , the first forceps member 10 is connected to the oscillating operation axis member 7 , which it can rotate around with a third pivotal supporting member ( third pivotal support ) 15 as its fulcrum . as shown in fig1 , the forceps section 3 has a connecting member 16 , which connects the second forceps member 12 to the opening - closing operation axis member 8 . one end 16 a of the connecting member 16 is connected to the opening - closing operation axis member 8 , which it can rotate around with a rotating axis member 17 as its fulcrum , and another end 16 b of the connecting member 16 is connected to the base 12 a of the second forceps member 12 , which it can rotate around with a fourth pivotal supporting member 18 as its fulcrum . the fourth pivotal supporting member ( fourth pivotal support ) 18 is provided on the opposite side of the rotating axis member 17 with respect to the central axis c of the forceps section 3 . the tip 8 a of the opening - closing operation axis member 8 , which connects to the connecting member 16 , is bendable so that it can follow the movement of the rotating axis member 17 . the first forceps member 10 is fitted with a leading groove 20 , which has a predetermined width and clips to the rotating axis member 17 ; the leading groove 20 runs from the base 10 a side of the first forceps member 10 toward the tip 10 b side , and extends in a straight line diagonally from the opening - closing operation axis member 8 side toward the fourth pivotal supporting member 18 side . the contacting faces of the rotating axis member 17 and the leading groove 20 may be coated so that they slide easily . the tip 12 b of the second forceps member 12 extends in opposition to the tip 10 b of the first forceps member 10 . it then bends from the position of the first pivotal supporting member 11 toward the oscillating operation axis member 7 side , and connects to the other end 16 b of the connecting member 16 at the base 12 a via the fourth pivotal supporting member 18 . the second pivotal supporting member 13 supports the first forceps member 10 from vertically above it so that it can rotated freely around the oscillating operation axis member 7 , and is provided between the oscillating operation axis member 7 and the opening - closing operation axis member 8 . as shown in fig1 , the first pivotal supporting member 11 is the base point when opening and closing the first forceps member 10 and the second forceps member 12 , and is provided nearer to the opening - closing operation axis member 8 side than the second pivotal supporting member 13 . the tip 8 a of the opening - closing operation axis member 8 is provided nearer to the tip 10 b of the first forceps member 10 than the second pivotal supporting member 13 . the first pivotal supporting member 11 and the third pivotal supporting member 15 are arranged separately on opposite sides of the central axis c of the forceps section 3 ; in addition , the first pivotal supporting member 11 , the insertion section 2 , and the third pivotal supporting member 15 , are arranged in this sequence from the tip 10 b of the first forceps member 10 to the base 10 a . subsequently , the method for using the forceps for endoscope 1 according to the embodiment described above will be explained . firstly , a method of switching from a state where the first forceps member 10 and the second forceps member 12 are closed , as shown in fig1 , to a state where the second forceps member 12 is open , as shown in fig2 , will be explained . in the state shown in fig1 , the operation section 5 is manipulated to move the opening - closing operation axis member 8 forward to the forceps section 3 side . at this time , a force acts on the rotating axis member 17 provided at the tip of the opening - closing operation axis member 8 , turning it toward tip of the forceps for endoscope 1 , but a resistive force from the leading groove 20 guides it in the direction of the leading groove 20 . when the opening - closing operation axis member 8 is moved further forward , the rotating axis member 17 moves along the leading groove 20 toward the tip 10 b side of the first forceps member 10 ; this pushes the fourth pivotal supporting member 18 outside the first forceps member 10 , and , via the fourth pivotal supporting member 18 , pushes the base 12 a of the second forceps member 12 outside . then , the tip 12 b side of the second forceps member 12 rotates counterclockwise ( as seen in fig1 ) around the first pivotal supporting member 11 . next , as shown in fig2 , the second forceps member 12 rotates downward with respect to the first forceps member 10 so that both reach an open state . when closing the second forceps member 12 so that it once more is positioned opposite the first forceps member 10 , the operation section 5 is manipulated so as to move the opening - closing operation axis member 8 backward to the operation section 5 side . since the rotating axis member 17 is now guided by the leading groove 20 toward the opening - closing operation axis member 8 side , and pulled back to the base 10 a side of the first forceps member 10 , the base 12 a of the second forceps member 12 moves toward the inner side of the first forceps member 10 via the fourth pivotal supporting member 18 , and the second forceps member 12 rotates clockwise ( as seen in fig2 ) around the first pivotal supporting member 11 . in this way , the first forceps member 10 and the second forceps member 12 are closed . subsequently , as shown in fig3 , an operation of oscillating to the second forceps member 12 side when the first forceps member 10 and the second forceps member 12 are closed will be explained . firstly , the oscillating operation axis member 7 is moved forward from the state shown in fig1 to the forceps section 3 side . this force is transmitted as rotational momentum via the third pivotal supporting member 15 to the first forceps member 10 , and the forceps section 3 begins to rotate counterclockwise ( as seen in fig1 ) around the second pivotal supporting member 13 . in accordance with this oscillation , the opening - closing operation axis member 8 is moved backwards . when the third pivotal supporting member 15 is moved nearer the tip 2 a side of the insertion section 2 than the second pivotal supporting member 13 in this way , the forceps section 3 rotates until the oscillating operation ends in the position shown in fig3 . to return the forceps section 3 along the insertion section 2 , the operation section 5 is manipulated to move the oscillating operation axis member 7 back to the operation section 5 side . this force is transmitted as rotational momentum via the third pivotal supporting member 15 to the first forceps member 10 , and the forceps section 3 begins to rotate clockwise ( as seen in fig3 ) around the second pivotal supporting member 13 . by moving the third pivotal supporting member 15 nearer to the operation section 5 side than the second pivotal supporting member 13 in this way , the forceps section 3 is returned to its position in the direction following the insertion section 2 . subsequently , a method of further opening the forceps section 3 when it is in the oscillated state , as shown in fig4 , will be explained . in the state shown in fig3 , the operation section 5 is manipulated to move the opening - closing operation axis member 8 forward in the same manner as already described . the tip 8 a of the opening - closing operation axis member 8 now bends while moving the rotating axis member 17 along the leading groove 20 . when the opening - closing operation axis member 8 is moved further forward , the rotating axis member 17 moves along the leading groove 20 to the tip 10 b side of the first forceps member 10 , the fourth pivotal supporting member 18 is pushed to the outside of the first forceps member 10 , and the base 12 a of the second forceps member 12 is pushed to the outside via the fourth pivotal supporting member 18 . then , the second forceps member 12 rotates counterclockwise ( as seen in fig3 ) around the first pivotal supporting member 11 . in this way , the second forceps member 12 is opened to the operation section 5 side with respect to the first forceps member 10 , as shown in fig4 . to close the second forceps member 12 so that it is once again opposite the first forceps member 10 , the operation section 5 is manipulated so that the opening - closing operation axis member 8 moves backward to the operation section 5 side . in a reverse movement to that described above , the rotating axis member 17 now moves along the leading groove 20 to the base 10 a side of the first forceps member 10 , whereby the fourth pivotal supporting member 18 returns to the operation section 5 side and the second forceps member 12 rotates clockwise ( as seen in fig4 ). thus , the first forceps member 10 and the 12 are closed . according to the forceps for endoscope 1 , at the time of oscillating by rotating the forceps section 3 to the opening - closing operation axis member 8 side , the second pivotal supporting member 13 is able to rotate without interfering with the tip 8 a of the opening - closing operation axis member 8 , due to the fact that the tip 8 a of the opening - closing operation axis member 8 is provided nearer to the tip 10 a side of the first forceps member 10 than the second pivotal supporting member 13 . furthermore , since the second pivotal supporting member 13 and the third pivotal supporting member 15 are arranged in that sequence from the tip side 10 a of the first forceps member 10 toward the base 10 b side , rotation in the above - mentioned direction can be achieved without any interference between the second pivotal supporting member 13 and the oscillating operation axis member 7 . therefore , the forceps section 3 can rotate more than 90 degrees around the second pivotal supporting member 13 . on the other hand , when attempting to rotate the forceps section 3 to the oscillating operation axis member 7 side , the tip 8 a of the opening - closing operation axis member 8 interferes with the second pivotal supporting member 13 , and the tip 2 a of the insertion section 2 interferes with the third pivotal supporting member 15 ; consequently , rotation in this direction can be restricted , minimizing the amount of protrusion of the connecting member 16 and the like from the forceps section 3 and reducing contact with the surrounding organism . since the leading groove 20 , which the rotating axis member 17 clips into , extends from the base 10 b side toward the tip 10 a side of the first forceps member 10 , and diagonally from the opening - closing operation axis member 8 side toward the fourth pivotal supporting member 18 side , at the time of opening and closing , the amount of movement of the tip 8 a of the opening - closing operation axis member 8 is restricted to the position where it interferes with the second pivotal supporting member 13 , enabling the amount of the connecting member 16 that protrudes outside the forceps for endoscope 1 to be reduced to a minimum . this invention is not limited to the embodiment described above , and may be modified in various ways without deviating from its main points . for example , although the leading groove 20 in the embodiment described above is a straight line , it may be curved instead . furthermore , although the tip 8 a of the opening - closing operation axis member 8 is bendable in the description above , it may be made from stiff material if a new link member is added . since the forceps for endoscope of the present invention has the above constitution wherein the pivotal supports are positioned as described above , when oscillating the forceps section so that it rotates to the opening - closing operation axis member side , the tip of the opening - closing operation axis member and the second pivotal support can rotate without interference , due to the fact that the tip of the opening - closing operation axis member is nearer the tip side of the first forceps member than the second pivotal support . furthermore , since the second and third pivotal supports are arranged in sequence from the tip of the first forceps member to the base thereof , the tip of the insertion section and the forceps section can rotate without interference . thus , the forceps section can rotate more than 90 degrees around the second pivotal supporting member . on the other hand , when rotating the forceps section to the oscillating operation axis member side , the tip of the opening - closing operation axis member interferes with the second pivotal supporting member , and the tip of the insertion section interferes with the third pivotal supporting member ; whereby rotation in this direction can be restricted . according to the forceps for endoscope of the present invention , the leading groove is formed in the first forceps member , thereby restricting the movement of the rotation axis member when opening and closing the forceps section . further , since the leading groove extends from the base side of the first forceps member toward the tip side thereof , and diagonally from the opening - closing operation axis member side toward the fourth pivotal supporting member side , the forceps section can be opened and closed by moving the rotation axis member within the leading groove . moreover , since the movement of the tip of the opening - closing operation axis member is restricted to the position where it interferes with the second pivotal supporting member , the amount of the connecting member that protrudes outside the forceps for endoscope can be reduced to a minimum .
this invention reduces the amount by which members protrude to the outside of a forceps for endoscope that can perform an oscillating operation , and reduces the amount of contact between an organism and parts other than the surgical instruments , thereby maintaining the visual field of the endoscope . the forceps for endoscope comprises an insertion section that is inserted inside a body cavity , an openable and closable forceps section provided at the tip of the insertion section , and a operation section for controlling the forceps section . the forceps section comprises a first forceps member , and a second forceps member , which faces the first forceps member and can rotate with a first pivotal supporting member as a fulcrum ; the second pivotal supporting member supports the first forceps member from vertically above it so that it can rotated freely around an oscillating operation axis member , and is provided between the oscillating operation axis member and an opening - closing operation axis member . a third pivotal supporting member supports the first forceps member from vertically outside , so that it can rotate around the oscillating operation axis member .