Forceps for an endoscopic operation

A forceps includes a pair of grip pieces which are pivotally supported about a first fulcrum to be mutually openable and closable. A pair of tip-end forceps pieces are pivotally supported about a second fulcrum to be mutually openable and closable. The second fulcrum is separated from the first fulcrum. An operation transferring member transfers opening and closing operation of the grip pieces about the first fulcrum to opening and closing operations of the tip-end forceps pieces about the second fulcrum.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a forceps for an endoscopic operation which is 
passed through a trocar to be used for performing an endoscopic operation 
in the body cavity. 
2. Description of the Related Art 
Recently, in various kinds of operations such as cholecystectomy, an 
endoscopic operation is widely performed. Such an endoscopic operation is 
performed without making a large incision and with thrusting plural trocar 
sheaths (hereinafter, referred to merely as "trocars") which are thin 
tubular members, into the somatic layer, and passing a surgical instrument 
and an endoscope through the trocars. 
In an endoscopic operation, forceps such as a grasping forceps which grasps 
organs, and a cutting forceps which cuts organs are necessary. Generally, 
such forceps are configured so that a pair of members in each of which a 
grip piece on the side of the basal end and a forceps piece on the side of 
the tip end are integrally formed are rotatably coupled to each other at a 
fulcrum in an X-shape. 
A forceps is passed through a trocar under a state where forceps pieces at 
the tip end are closed so as to reduce the size in section. In the body 
cavity, preferably, the tip end forceps pieces are widely opened. 
As shown in FIG. 9, however, the open angle .theta. of tip end forceps 
pieces 91 is restricted by the inner diameter of a trocar 100. In a 
related art forceps for an endoscopic operation which is configured as 
described above, therefore, the open angle .theta. is restricted by the 
both end openings of the trocar 100. 
The open angle .theta. is maximum when the fulcrum 92 is at to the middle 
of the trocar 100 in the longitudinal direction as shown in FIG. 9, and 
hence Tan(.theta./2) cannot be made large. Unless the trocar 100 is made 
unrealistically thick and short, consequently, a large open angle .theta. 
cannot be attained. 
Even when a diseased part is slightly large, therefore, the part cannot be 
surely grasped or cut. As a result, an endoscopic operation cannot be 
adequately performed. 
SUMMARY OF THE INVENTION 
In view of the above problems, an object of the invention is to provide a 
forceps for an endoscopic operation in which tip end forceps pieces can be 
widely opened under a state where the forceps is passed through a usual 
trocar. 
In order to attain the object, the forceps for an endoscopic operation of 
the invention includes: a pair of grip pieces which are pivotally 
supported to be mutually openable and closable about a first fulcrum; a 
pair of tip-end forceps pieces which are pivotally supported to be 
mutually openable and closable about a second fulcrum separated from the 
first fulcrum; and an operation transferring member which transfers 
opening and closing operations of the grip pieces about the first fulcrum 
to opening and closing operations of the tip-end forceps pieces about the 
second fulcrum. 
The operation transferring member preferably has a thickness which passes 
through a trocar. 
The operation transferring member may include an arm which is link-coupled 
to a first member provided on a first fulcrum side of the grip pieces, and 
to a second member provided on a second fulcrum side of the tip-end 
forceps pieces. 
The operation transferring member may include: a pin projected from one of 
a third member provided on a first fulcrum side of the grip pieces, and a 
fourth member provided on a second fulcrum side of the tip-end forceps 
pieces; and a long groove which engages with the pin and is formed in the 
other of the third member and the forth member. 
The operation transferring member may include a gear which meshes with a 
fifth member provided on a first fulcrum side of the grip pieces, and with 
a sixth member provided on a second fulcrum side of the tip-end forceps 
pieces. 
One of said tip-end forceps pieces may swing across a line connecting the 
first fulcrum with the second fulcrum, whereby being swingable to the side 
of the other of the tip-end forceps pieces. 
The operation transferring member may have a stopper regulating a swing 
range of the tip-end forceps pieces. 
One of the grip pieces and one of the tip-end forceps pieces may be fixed 
to each other. The tip-end forceps pieces may be scissors members or 
grasping members. 
The present disclosure relates to the subject matter contained in Japanese 
patent application No. Hei. 9-005422 filed on Jan. 16, 1997 and Japanese 
patent application No. Hei. 9-339549 filed on Dec. 10, 1997 which are 
expressly incorporated herein by reference in theirs entirety.

EXPLANATION OF THE FORCEPS FOR AN ENDOSCOPIC OPERATION 
This explanation will be described with reference to the accompanying 
drawings. 
FIG. 1 shows a cutting forceps which is a first forceps for an endoscopic 
operation and which is used in an endoscopic operation with being passed 
through a trocar. 
A pair of grip pieces 1 which are disposed on the basal end side are 
pivotally supported to be mutually openable and closable about a first 
fulcrum 3 which is disposed in the vicinity of an end of each of support 
side plates 2. Each of the grip pieces 1 can be independently swung about 
the first fulcrum 3. A ring-like finger hold la is formed in the end 
portion of each grip piece 1 on the basal end side. 
A pair of tip-end forceps pieces 4 on each of which a cutting edge 4a is 
formed are pivotally supported to be mutually openable and closable about 
a second fulcrum 5 which is disposed in the other end portions of the 
support side plates 2 so as to be separated from the first fulcrum 3. The 
opening and closing operations of the grip pieces 1 are transferred to the 
tip-end forceps pieces 4, by an operation transferring unit 10 which is 
disposed along the support side plates 2. 
FIG. 2 is an exploded view of the operation transferring unit 10. The 
paired support side plates 2 are disposed in the outsides on both sides. 
In each of the support side plates 2, shaft holes are opened at the 
fulcrums 3 and 5, respectively. Shafts 11 and 12 passing through the shaft 
holes at the fulcrums 3 and 5 are loosely fitted into shaft holes 1b and 
4b which are made in the grip pieces 1 and the tip-end forceps pieces 4, 
respectively. Therefore, the grip pieces 1 and the tip-end forceps pieces 
4 can be swung about the shafts 11 and 12, respectively. 
The base portion of each of the grip pieces 1 and the tip-end forceps 
pieces 4 is formed into a disk-like shape which is centered at the shaft 
hole 1b or 4b. End portions of rod-like arms 13 which couple the disk 
portions 1c of the grip pieces 1 with the disk portions 4c of the tip-end 
forceps pieces 4 are rotatably connected to the disk portions by small 
pins, respectively. 
A pair of arms 13 are disposed so as to respectively couple one of the grip 
pieces 1 with one of the tip-end forceps pieces 4, and the other grip 
piece 1 with the other tip-end forceps piece 4. When the grip pieces 1 on 
the basal end side are operated to be mutually opened or closed, 
therefore, the operation is transferred to the tip-end forceps pieces 4 
via the arms 13, so that the tip-end forceps pieces 4 are mutually opened 
or closed. 
The reference numerals 14 and 15 designate recesses (escapes) which are 
formed in the disk portions 1c and 4c in order to prevent the disk 
portions 1c and 4c and the arms 13 from interfering with each other in a 
required operation range. 
The recesses 14, 15 are formed in a shape which regulate the swing range of 
the tip-end forceps pieces 4 so that the arms 13 are abutted on side 
surfaces of the recesses 14, 15, when the tip-end forceps pieces 4 are 
swung about the second fulcrum 5. 
FIG. 3 schematically shows a state where the first forceps for an 
endoscopic operation is used with being passed through the trocar 100. The 
open angle .theta. of the tip-end forceps pieces 4 is restricted by the 
inner diameter of the trocar 100, particularly, the width of the both end 
openings. 
The first and second fulcrum 3 and 5 are located at positions which are 
closer to the both end openings than the middle of the trocar 100, 
respectively. Consequently, Tan(.theta./2) can be made larger, so that the 
tip-end forceps pieces 4 can be widely opened. 
In an endoscopic operation, therefore, even a large diseased part can be 
easily grasped or cut while passing the forceps through the usual trocar 
100. When the distance between the first and second fulcrum 3 and 5 is set 
to be no less than the length of the trocar 100, the open angle .theta. is 
not restricted by the dimensions of the trocar 100. 
As shown in FIG. 4, the pair of grip pieces 1 may be swung in the same 
direction about the first fulcrum 3. This causes the pair of tip-end 
forceps pieces 4 to be swung together about the second fulcrum 5. 
Consequently, operations such as grasping and cutting can be easily 
performed on even a diseased part which is not in front of the trocar 100. 
FIG. 5 shows a second forceps for an endoscopic operation. One of the grip 
pieces 1 and one of the tip-end forceps pieces 4 are coupled with each 
other by the arm 13 in the same manner as the first forceps, and the other 
grip piece and the other tip-end forceps piece are integrally formed via a 
coupling plate 18. 
According to this configuration, although only one of the paired tip-end 
forceps pieces 4 is operated by the grip pieces 1, the opening and closing 
operations of the tip-end forceps pieces 4 can be realized by a simple 
structure of the operation transferring unit 10. 
In this second forceps for an endoscopic operation, the swing range of the 
tip-end forceps pieces 4 is regulated by abutting the arm 13 on the recess 
15 of the tip-end forceps pieces 4 side. Such a single-fixed structure may 
be employed also in forceps for an endoscopic operation described below. 
FIGS. 6A and 6B show a third forceps for an endoscopic operation. The 
operation transferring unit 10 is configured by pins 21 respectively 
projected from end portions of the grip pieces 1 which swing about the 
first fulcrum 3, and long grooves 22a or long holes 22b respectively 
formed in end portions of the tip-end forceps pieces 4 which swing about 
the second fulcrum 5. 
The long grooves 22a or the long holes 22b are formed in the end portions 
of the tip-end forceps pieces 4 in the longitudinal direction of the 
tip-end forceps pieces 4. The pins 21 are formed so as to have a thickness 
at which the pins can be moved in the long grooves 22a or the long holes 
22b without backlash and resistance. 
When the grip pieces 1 are operated to be mutually opened or closed about 
the first fulcrum 3, therefore, the operation is transferred to the 
tip-end forceps pieces 4 via the pins 21 and the long grooves 22a or the 
long holes 22b, so that the tip-end forceps pieces 4 are mutually opened 
or closed. 
Alternatively, the pins 21 may be disposed on the tip-end forceps pieces 4 
and the long grooves 22a or the long holes 22b may be disposed in the grip 
pieces 1. As shown in FIG. 6B, the long holes 22b which close an outside 
ends of the tip-end forceps pieces 4 may be constructed so as to pass the 
pins 21. In this construction, the opening angle of the tip-end forceps 
pieces 4 is regulated by abutting the pin 21 on an outside ends of the 
long holes 22b. 
FIG. 7 shows a fourth forceps for an endoscopic operation. A gear 24 is 
supported on the support side plate 2 so as to be rotatable about a shaft 
25. The gear 24 meshes with a member on the side of the grip pieces 1 
which swing about the first fulcrum 3, and with a member on the side of 
the tip-end forceps pieces 4 which swing about the second fulcrum 5. 
According to this configuration, when the grip pieces 1 are operated to be 
mutually opened or closed about the first fulcrum 3, the operation is 
transferred to the tip-end forceps pieces 4 via the gear 24, so that the 
tip-end forceps pieces 4 are mutually opened or closed. 
FIG. 8 shows a fifth forceps for an endoscopic operation which is applied 
to a grasping forceps. In the fifth forceps, doughnut-shaped holding 
portions 4d are formed at the front ends of the tip-end forceps pieces 4, 
respectively. The holding portions may have any other adequate shape. Any 
one of the operation transferring units of the above-described forceps may 
be used as the operation transferring unit 10 of this fifth forceps. 
The foregoing description of the preferred embodiments of the invention has 
been presented for the purpose of illustration and description only. It is 
not intended to be exhaustive or to limit the invention to the precise 
form disclosed, and modifications and variations are possible in light of 
and within the scope of the invention. The preferred embodiments were 
chosen and described in order to explain the principles of the invention 
and its practical application to enable one skilled in the art to utilize 
the invention in various embodiments and with various modifications as are 
suited to the particular use contemplated. It is intended that the scope 
of the invention be defined by the claims appended hereto, and equivalents 
thereof. 
According to the above-described forceps, the grip pieces and the tip-end 
forceps pieces are respectively opened or closed about two fulcrums which 
are separated from each other. Therefore, the tip end forceps pieces can 
be widely opened under a state where the forceps is passed through a usual 
trocar, and even a large diseased part can be easily grasped or cut in an 
endoscopic operation.