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Description  |
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BACKGROUND OF THE INVENTION
The present invention broadly relates to laparoscopic surgical instruments.
More particularly, the invention relates to disposable surgical
instruments which include disposable end effectors such as cutters,
graspers, and dissectors which are useful in a laparoscopy procedure.
The laparoscopy procedure has recently become a widely practiced surgical
procedure. A laparoscopy procedure involves incising through the navel and
through the abdominal wall for viewing and/or operating on the ovaries,
uterus, gall bladder, bowels, appendix, or general abdominal surgery.
Typically, trocars are utilized for creating the incisions. Trocar tubes
are left in place in the abdominal wall so that laparoscopic surgical
tools may be inserted through the tube. A camera or magnifying lens is
often inserted through the largest diameter trocar tube (e.g. 10 mm
diameter) which is generally located at the navel incision, while a
cutter, dissector, or other surgical instrument is inserted through a
smaller diameter trocar tube (e.g. 5 mm diameter) for purposes of
manipulating and/or cutting the internal organ. Sometimes it is desirable
to have several trocar tubes in place at once in order to receive several
surgical instruments. In this manner, organ or tissue may be grasped with
one surgical instrument, and simultaneously may be cut or stitched with
another surgical instrument; all under view of the surgeon via the camera
in place in the navel trocar tube.
The laparoscopic tools of the prior art are primarily reusable stainless
steel tools. Between each use of a stainless steel tool, the tool must be
soaked, scrubbed, and disinfected. The usual procedure is then to dry the
tool, wrap it, and put it in a steam autoclave. The tool is kept sterile
until just prior to use when it is removed from the autoclave and
unwrapped in the locale of the sterile field of use.
While reusable laparoscopic tools have functioned well for their intended
purpose, the process of sterilizing the tool is problematic. Small pieces
of tissue or organ often become lodged in the end effectors, and much
labor is required to ensure that complete sterility is obtained and
maintained. In addition, over time, sharp laparoscopic instruments such as
a scissors get dull and must be discarded. However, prior to use of a
particular instrument, the surgeon is not able to discern the state of the
instrument and whether the instrument will satisfy the surgeon's
requirements.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide disposable
laparoscopic surgical instruments.
It is another object of the invention to provide disposable laparoscopic
surgical instruments having investment cast end effectors.
It is a further object of the invention to provide disposable single and
double-acting laparoscopic surgical instruments which utilize improved
linkage systems.
It is yet another object of the invention to provide disposable
laparoscopic surgical instruments which utilize a uniform push rod and
handle end, to which any of a plurality of end effectors are attached.
It is even a further object of the invention to provide disposable Maryland
dissector suitable for insertion in a 5 mm trocar tube.
Additional objects of the invention include providing disposable
laparoscopic surgical instruments of improved design with smooth
transitions from an insulating shrink wrap to the end effectors and to the
handle.
In accord with the objects of the invention, a disposable laparoscopic
surgery instrument generally includes, a tube, a push rod which extends
through the tube, an actuating means engaging the tube and the push rod
for imparting reciprocal axial motion to the push rod, end effector means
coupled to the push rod by linkage means which are also coupled to the
push rod, and a clevis coupled to the tube at its proximal end and to the
end effector means at its distal end, wherein axial movement of the push
rod effects movement of the end effector means in a plane parallel to the
longitudinal axis of the push rod. Plastic shrink wrap is preferably
utilized to electrically insulate the disposable instrument and extends
over the aluminum tube and over at least an adjacent portion of the
clevis. The tube and push rod are preferably made of aluminum, the clevis
is preferably made of a high-strength aluminum alloy, the actuating means
is preferably made of plastic and aluminum, and the end effector means is
preferably made of investment cast bronze.
The clevis of the invention is preferably a separately formed clevis having
a knurled rod-like proximal end for mating with the end of the aluminum
tube, and a post-supporting U-shaped distal portion for holding the end
effector means. The post in the distal portion is perpendicular to the
legs of the U-shaped distal portion and is arranged to extend through
hole(s) in the end effector means. In this manner, the blades or prongs of
the end effector means are held by, but can rotate around the post. Each
leg of the U-shaped distal portion of the clevis also preferably includes
a notch which serves as a terminating location for the shrink-wrap.
Another aspect of the clevis relates to the forming of the post integral
with one of the legs of the distal portion of the clevis.
The end effector means of the invention can take any of many forms, such
as, e.g., a scissors, a dissector, or a grasper. Additionally, the end
effector means can be double acting or single acting. Regardless of the
type of end effector utilized, the end effector is arranged with a hole to
accept the post of the clevis so that the end effector can rotate around
the post.
According to one aspect of the invention the push rod is flattened on its
distal end, and the linkage means which couples the push rod and the end
effector is a staple which extends through a hole in the flattened end of
the push rod as well as another hole in the proximal end of the end
effector. Because the outer tube is positioned at a fixed distance from
the rotation hole in the end effector (due to the clevis), when the push
rod is moved axially relative to the tube, the end effector cannot move
axially. However, because the push rod is also a fixed distance away from
another hole in the proximal end of the end effector (due to the staple),
movement of the push rod relative to the tube causes rotation of the end
effector in a plane. In other words, movement of the push rod relative to
the tube causes the hole through the end effector through which the staple
extends to rotate along an arc centered at the rotation hole in the end
effector through which the post of the clevis extends. Movement in this
manner typically effects a cutting, dissecting or grasping action.
Single acting end effectors can include one hole in the flattened end of
the push rod and one staple for connecting the moving prong or blade of
the end effector to the push rod. A double acting end effector
correspondingly includes two holes in the flattened end of the push rod
and two staples; one for each prong or blade. If desired, a single acting
end effector can eliminate the staple by forming one end of the pull wire
into a "dog's leg" and by inserting the dog's leg pull rod end into the
hole in the proximal end of the end effector.
According to other aspects of the invention, a 5 mm Maryland Dissector with
jaws which are slightly less severely curved than that of the prior art,
but with more than a 5 mm tip to top offset is provided. The 5 mm Maryland
dissector utilizes an identical push rod, tube, staple connector, and
clevis as does the double acting scissors. The through-holes in the jaws
through which the post of the clevis extends are slightly larger than the
similar through-holes located in the other end effectors of the invention.
With the slightly larger holes, when pushing the 5 mm Maryland dissector
through a 5 mm trocar tube, the jaws of the Maryland dissector are
angularly displaced relative to the clevis. Upon passing through the
trocar tube to the surgery situs, the jaws can resume their normal
position.
Additional aspects of the invention include: a ferrule which is snapped
onto the handle ridge for guaranteeing continuity of insulation from the
tube to the handles; a knurled knob handle lever for allowing activation
of the lever when the fingers of the surgeon are holding the ferrule area
rather than the scissor like gripping handles of the actuator;
modifications in shape to the proximal portion of the end effectors for
reinforcement purposes; and a single acting scissors which utilizes a
zigzag in the push rod instead of a staple connector.
A better understanding of the disposable laparoscopic surgical instruments
of the invention, and additional advantages and objects of the invention
will become apparent to those skilled in the art upon reference to the
detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view, partly in section, of a disposable
laparoscopic instrument prior to insertion into a trocar tube, and, in
partial phantom format, after insertion into a trocar tube;
FIG. 2a is a side elevation view, partly in section, of the clevis of the
invention in conjunction with the distal end of the tube and shrink wrap
of the invention;
FIG. 2b is a cross-section view of the device of FIG. 2a;
FIG. 3 is a side elevation view of an alternate clevis embodiment of the
invention prior to assembly with end effectors
FIG. 4a is a partially broken-away side elevation view of the actuating
handle of the disposable laparoscopic instrument of the invention;
FIG. 4b is a rear elevation view of the device of FIG. 4a;
FIG. 5a is a side elevation view, partly in section, of a double acting
dissector in conjunction with the clevis and the distal ends of the rod
and tube of the disposable laparoscopic instrument of the invention, with
the staple linkage means shown in perspective and broken out views;
FIG. 5b is a plan view of the device of FIG. 5a;
FIG. 5c is an enlarged side view of the connection of the distal end of the
rod and the proximal ends of the staple linkage means of FIG. 5a;
FIGS. 5d and 5e are enlarged top views of the distal end of the rod and the
proximal ends of the staple linkage means when the blades of the double
acting dissector are in open and closed positions respectively;
FIG. 5f is a side elevation view of a double acting dissector utilizing a
crossed staple linkage means;
FIG. 5g is an enlarged top view of the distal end of the rod and the
proximal end of the crossed staple linkage means
FIG. 6a is a side elevation view of a first embodiment of a single acting
scissors of the invention in conjunction with the clevis, and the distal
ends of the rod and tube of the disposable laparoscopic instrument of the
invention;
FIG. 6b is a side elevation view of a second embodiment of a single acting
scissors;
FIG. 7a is an elevation view in cross-section of a Maryland dissectors
according to the invention;
FIG. 7b is a plan view of the Maryland dissector of FIG. 7a;
FIG. 8a is a plan view of one element of an investment cast end effector in
accordance with the present invention;
FIG. 8b is a side elevation view of the device of FIG. 8a;
FIG. 9a is a side elevation view in section of a ferrule shielding device
of the present invention engaged with the shrink wrapped aluminum tube and
handle of the invention; and
FIG. 9b is a cross-section view of the device of FIG. 9a.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIG. 1, a disposable laparoscopic surgical instrument is
indicated at 10. The disposable laparoscopic surgical instrument 10
broadly comprises an aluminum tube 15 surrounded by a peripheral
insulating shrink wrap layer of plastic 20, a clevis means 30, end
effectors 40, actuating means 50, and a push rod 60. The clevis means 30
is advantageously a separately formed aluminum piece which fixedly engages
aluminum tube 15 as described in more detail hereinafter. The clevis 30
also engages the end effectors 40 which are pivotally engaged to clevis 30
at pivot pin 45. The end effectors 40 are preferably formed of investment
cast bronze as disclosed in copending U.S. Ser. No. 07/521,766 which was
previously incorporated by reference herein. The push rod 60, which is
also formed of aluminum, is engaged at its distal end 65 to the end
effectors 40, as hereinafter more fully described, and is connected at 70,
at its proximal end to a manually operable actuating means 50. For purpose
herein, the "distal end" of the instrument 10 or any part thereof, is the
end closest to the surgical site and distant from the surgeon, while the
"proximal end" of the instrument 10 or any part thereof, is the end most
proximate the surgeon and distant the surgical site.
In use, the laparoscopy instrument 10 is inserted with the blades or
graspers 90, 92 of the end effector 40 in the closed position, into trocar
tube 80, as indicated at the arrow 85 of FIG. 1. The distal portion of the
instrument 10 passes through the trocar tube 80 into body incision 100.
Upon the distal portion of the laparoscopy instrument 10 exiting the
trocar tube 80, the blades 90, 92 can be opened and closed as indicated at
105 by reciprocal motion of push rod 60 which results from operation of
the manual actuating means 50. As is discussed more fully hereinafter, the
clevis effectively translates the reciprocal motion of the push rod 60
into the end effector means action indicated at 105.
Turning to FIGS. 2a and 2b, a preferred configuration of the clevis 30 of
the present invention is seen. The clevis has a knurled rod-like proximal
portion 34 for mating with the end of the aluminum tube 15, and a
post-supporting U-shaped distal portion 32 for holding the end effector
means. The outer diameter of the distal portion 32 of the clevis is larger
than the outer diameter of the proximal portion 34; shoulder 39 being
formed therebetween. The proximal portion 34 of the clevis is preferably
hollow, as indicated at 33, to permit the push rod 60 to extend
therethrough. The distal portion 32 of the clevis 30 is provided with legs
36 and a post or pivot pin 45. The post 45 is generally perpendicular,
i.e. transverse, to the legs 36 of the clevis and is arranged to extend
through hole(s) 39 in the end effector means 40. In this manner, the
blades or prongs of the end effector means 40 are held by, but can rotate
around, i.e. are rotatably engaged with the post 45.
As seen in FIG. 2a, a recess or notch 380 is provided which extends across
each leg 36 of the clevis 30. Consequently, a peripherally applied
electrically insulating plastic wrap 20 can be end-cut at recess 380 and a
smooth transition from the end effector means 40 via the clevis 30 to tube
15 can be achieved. Even if slight outward flaring of wrap 20 occurs at
the end-cut, as is common, this flaring can be tolerated as it will be
within the envelope of the normal outer surface indicated at 43.
Clevis 30 is preferably made from a high strength aluminum base alloy (e.g.
2024 alloy of Alcoa) which is preferably harder than the aluminum base
alloy (e.g. 6061 or 6063 alloys of Alcoa) from which tube 15 is
fabricated. The post portion of the clevis may be made out of the
identical alloy or, for added strength, out of a stainless steel nail. In
assembly of the laparoscopy surgical instrument 10, serrated or knurled
portion 34 of clevis 10 is fit snugly into tube 15 such that the walls of
tube 15 abut the peripheral shoulder 39 of clevis 30, with the outer
surface of tube 15 and the adjacent outer surface of clevis 30 having
essentially the same diameter. Mechanical pressure is then applied to tube
15 peripherally at the location of knurled portion 34, thereby crimping
the end portion of tube 15 onto the knurled portion 34. Mechanical
pressure causes the projections of the knurls to bite into and firmly
engage tube 15 as indicated at 37 due to the higher hardness of the clevis
material. Once the clevis 30 and tube 15 have been properly joined, the
plastic shrink wrap 20 can be applied over the tube 15 and an adjacent
portion of the clevis 30 and end-cut at recess 380.
FIG. 3 shows an alternate embodiment for the clevis means of the present
invention wherein the clevis 30 is formed and machined from aluminum base
alloy as one integral element. As seen in FIG. 2b, the arms 36' of clevis
30 are bent outwardly away from each other. Pivot pin 45' is integral with
one arm 36' as indicated at 48 and has a terminal portion 47 of reduced
diameter which will engage slightly larger hole 49 when the arms 36 are
bent inwardly and parallel with each other (i.e. after end effectors 40 of
FIG. 2a are attached). Upon bending of the arms 36', the tip of terminal
portion 47 engages and is suitably flattened in recess 59 as indicated at
53.
With reference to FIGS. 4a and 4b, manually operable actuating means are
indicated at 50 which includes an electrically insulating housing 914
having a fixed handle portion 410 integral therewith and a lever portion
420 pivotally engaged to housing 914 at pivot pin 430. Push rod 60 passes
through aluminum tube 15 (covered by shrink wrap 20) and engages cross pin
440 at 454; set screw 441 being used to extend into cross pin 440 and set
push rod 60 in the cross pin 440. The cross pin 440 is fixedly positioned
in lever member 420. Upon pivotal motion of lever arm 420, as indicated at
450, using a conventional hand grip as indicated at 455 to apply pressure
to extended handle element 456 of lever member 420, push rod 60 will move
linearly as indicated at 460 to actuate an end-effector (not shown in FIG.
4a) coupled thereto as hereinabove described. There may be occasions, in
the course of certain laparoscopic procedures, that certain surgeons will
prefer to hold the actuating means 50 in the manner indicated at 465 with
fingers grasping housing 914 and the thumb 467 adjacent a portion 470 of
lever member 420 which is positioned on the opposite side of cross-pin 440
from extended handle element 456.
Thus, in accord with one aspect of the invention, a roughened knurled or
serrated surface 480 is provided integral with portion 470 of lever member
420 to enable a frictional engagement with thumb 467. Utilizing serrated
surface 480, when thumb motion as indicated at 490 is initiated, pivotal
motion of lever arm 420 is accomplished, as indicated at 450, as is the
linear motion of push rod 60 as indicated at 460.
With reference to FIGS. 5a-5g, details are seen of an end effector 40 and
the linkage means for linking the end effector 40 to the push rod 60. In
particular, in FIGS. 5a-5g, a double acting dissector is shown with blades
90', 92' which are respectively rotatably mounted on pivot pin 45 of
clevis 30'. Each blade 90', 92' of the dissector has a forwardly extending
manipulating portion 94, and a rearwardly extending planar base portion 96
with a through-hole 98. Each of the through-holes 98 of planar base
portions 96 is separately engaged by a separate connecting or linkage
means 110, 112.
As shown in FIG. 5a, according to one preferred embodiment, each linkage
means 110, 112 is in the form of a thin metal member generally in the
shape of an outwardly flared staple. Each linkage means may be generally
described as having a U-shaped section 114 with a base 111 perpendicular
to and bridging the arms 118 of the U, and two generally parallel spaced
apart outwardly extending side or tab elements 113 which are generally
parallel to base 111. Each of the linkage means 110, 112 has one of its
tab elements 113 engaged in a through-hole 98 of a planar base 96, with
the U-shaped section of the linkage means extending respectively in
opposite directions as illustrated. The other tab element 113 of the
linkage means 110, 112 engage through-holes 120 formed in a flattened
plate-like terminal portion 122 of push rod 60 (as seen more clearly in
FIGS. 5d-5f). As can be seen from FIG. 5a, movement of push rod 60 in the
direction indicated at 124 will cause blades 90', 92' to move in the
direction indicated at 127 to the position 129 without interference
between the oppositely positioned staple-like linkage means 110, 112.
Correspondingly, the tab elements 113 of the linkage means 110, 112 which
extend through the flattened terminal portion 122 of push rod 60 will move
from their position shown in FIG. 5d, to the position shown in FIG. 5e.
That manipulators (blades) 90' and 92' open and close in response to the
axial movement of push rod 60 may be understood by understanding the
relationship of the clevis 30' and linkage means 110, 112 to the blades
90', 92', the push rod 60, and the tube 15. In particular, due to the fact
that the clevis 30' is rigidly attached to the tube 15 (as described above
with reference to FIG. 2a), the tube 15 is a fixed distance from the
rotation pin 45 of the clevis, and hence to the holes in the blades 90'
and 92' through which rotation pin 45 extends. Thus, when the push rod 60
is moved axially relative to the tube 15 (the tube being fixed in place),
the blades of the end effector cannot move axially with the push rod.
However, because the push rod 60 is also a fixed distance away from holes
98 in the base portion of the end effector blades (due to staple linkage
means 110, 112), movement of the push rod relative to the tube must cause
movement of the holes 98 in the end effector blades. Because one part each
blade is fixed, but another part must move when the push rod 60 is moved
relative to the tube 15, end effector blades 110 and 112 rotate along an
arc centered at the fixed rotation hole in the end effector through which
the post 45 of the clevis 30' extends. Movement in this manner typically
effects a cutting or grasping action.
FIGS. 5f and 5g show another embodiment of the linkage means which
increases the stability of the end effector means 40. In FIGS. 5g and 5h
it is seen that the linkage means 110', 112' do not respectively engage
the nearest of the through-holes 120 transversely aligned in the
plate-like terminal portion 122 of push rod 60, but instead cross-over as
indicated at 130. With this arrangement the angle 73 , indicated at 135,
is increased. The increase in this angle affords a more stable instrument,
because the amount of "shake" which results from the unavoidable
clearances at the pivot 45 is reduced; i.e., as .THETA. approaches
90.degree., the amount of free movement at the end of an end-effector
blade 90', 92' is minimized.
FIGS. 6a shows a single acting scissors. Essentially, the single acting
scissors is identical to the double acting scissors of FIGS. 2a-2g except
that blade 692 is stationary; hence no staple is used to connect blade 692
to rod 660. While blade 692 is stationary, blade 690 pivots as indicated
at 627 around pin 645. To ensure rotational movement of blade 690 upon
axial movement of rod 660, the end 22 of rod 660 should be supported.
FIG. 6b shows a preferred embodiment of a single acting scissors where
instead of utilizing a pull rod with a flattened end, pull rod 660' is a
very thin wire of staple thickness (e.g. 25 mils) which has a rigid
dog's-leg or Zig-Zagged end which extends through hole 698 of the proximal
end of scissor blade 690. A similar pull rod is shown in previously
incorporated U.S. Ser. No. 07/521,766, where instead of a single acting
scissors, a radial jaw biopsy forceps is shown.
With reference to FIGS. 7a and 7b a disposable laparoscopic Maryland
dissector for use in a 5 mm diameter trocar tube 80 is shown; the actual
inner diameter 720 of a "5 mm" trocar tube typically being about 6 mm).
Traditionally, relatively large trocar tubes (e.g. 10 mm) are required
when using Maryland dissectors, as the distance from the blade tips 701 to
the top of rod (i.e., the width of the curved jaws as indicated at 710) is
relatively large. Of course, larger trocar tubes inflict more trauma on
the patient. Thus, it is desirable to be able to place a Maryland
dissector in a smaller diameter trocar tube, e.g. a 5 mm trocar, such as
indicated at 720.
In conjunction with curved jaws or blades 700, the 5 mm Maryland dissector
of the invention preferably utilizes an actuator mechanism such as shown
in FIGS. 4a and 4b, tube 715, push rod 760, linkage means such as shown in
FIG. 5a, and clevis 730 which are substantially identical to the double
acting equivalent devices seen in the double acting dissector embodiments
of FIG. 1 and FIGS. 5a-5g. In the Maryland dissector of the present
invention, the curve of jaws 700 is slightly less severe than a standard
Maryland Dissector. However, the less severe curve does not by itself
permit accommodation in a 5 mm trocar tube. Rather, the pivot holes 797 in
the end effector blades of the Maryland dissector are arranged to be large
enough to accommodate the required angular displacement (as indicated by
angle B in an exaggerated manner) of the blades relative to the clevis and
pivot axle 745. In other words, extra clearance is provided where pivot
axle 745 of the clevis 730 fits into the rear portion of the end effector
such that the end effectors can assume an angled position of preferably up
to eight degrees (745) when the Maryland dissector is being pushed through
trocar tube 80, and can assume their normal position (745') which is
substantially parallel to the arms 736 of the clevis 730 when the jaws 700
have passed through the trocar tube 80 and have assumed their normal
position (700'). In addition, the flexibility of the aluminum tube, which
is greater than that of a stainless steel tube which is used in
traditional instruments, allows freedom for the curved instrument to pass
through the trocar tube as indicated at 775.
With reference to FIGS. 8a and 8b, when an investment castable metal, such
as bronze, is used in the making of an end effector 92', all features of
the end effector are formed during casting to provide an integral end
effector element. This is in contrast with the prior art practice of
stainless steel end effectors which involved forging and machining to
achieve the desired finished forms. While stainless steel is stronger than
bronze, the use of investment cast bronze eliminates the need for forging
and machining and also abrasive blasting and pickling and other treatments
required in stainless steel fabrication which interfered with the
achievement of close tolerances. Since investment cast bronze, while of
considerable strength, is not as strong as stainless steel, it is
advantageous to provide a novel configuration for the end effectors, e.g.
92', by including integral reinforcing elements in the investment cast end
effector. In FIGS. 8a and 8b the extended cutting portion 94 and the base
portion 96 are conventionally laterally offset as indicated at 98. In the
prior art, the offset portions 94,96 join at essentially a right angle
whereas in the present invention an integral mass of investment cast
metal, in the form of a fillet 129, bridges the offset base and cutting
portions and significantly strengthens the end effector. As shown in FIG.
8a, the flared staple linkage means 110 pivotally rotates in through-hole
98 in the base end effector portion 96, with its tab element 113 rotating
through the angular segment 101 defined by radii 105, 107 extending from
through-hole 98. Angular segment 101 is less than 180.degree. of arc, e.g.
typically 90.degree.-120.degree.. The supplementary arc segment 108 is
more than 180.degree., typically 240.degree. to 270.degree., which is the
angular difference between segment 101 and 360.degree.. Segment 108 is
filled with an integral mass of cast metal 119 adjacent and enveloping
through-hole 98 which strengthens base 96 but does not interfere with the
rotation of flared element 113. The height of the segmental metal mass 119
is preferably at least equal to the diameter of tab element 113.
With reference to FIGS. 9a and 9b, and in reference to another aspect of
the invention, a ferrule type connecting means 910 is shown. Ferrule 910
provides a secure electrically insulating connection which peripherally
bridges the exposed peripheral, electrically conductive, lateral portion
912 of aluminum tube 20 located between electrically insulating plastic
shrink wrap 20 and the electrically insulating housing 914 of manually
operable actuating means 50 which closely surrounds the aluminum tube 15.
The portion of electrically insulating housing adjacent the terminal
portion 916 of electrically insulating shrink wrap 20 is provided with a
flat-surfaced peripheral ridge 920. Ridge 920 has a substantially
perpendicular wall 922 in the direction away from the shrink wrap 20. Wall
922 forms one side of a frusto-conical peripheral groove 921 which slopes
upwardly away from perpendicular wall 922 until it terminates at wall 923.
Ridge 920 further has a substantially frusto-conical surface 924 which
slopes toward and is closely adjacent but slightly spaced from the shrink
wrap 20 as indicated at 926.
Ferrule means 910 has a generally conical outer surface 929. The inner
surface of ferrule means 910 is provided with a cylindrical passage 930
which is adapted to be closely adjacent to and surround a portion of
shrink wrap 20, and is slidable with respect thereto. Contiguous to
cylindrical passage 930, and coaxial therewith, is an outwardly flaring
frusto-conical passage 932 which bridges and is spaced from the peripheral
electrically conductive portion 912 of aluminum tube 20. Outwardly flaring
frusto-conical passage 932 is bounded at its wider flared end by a flat
peripheral rim of extension 934 which is adapted to abut the flat surfaced
peripheral ridge 920 of the portion 914 of the electrically insulating
housing 50. An axially inwardly depending perpendicular peripheral wall
936 of the outwardly flaring frusto-conical projection 938 abuts the
peripheral wall 922 of the electrically insulating housing 914 of
actuating means 50. Projection 938 is matingly seated in the extended
frusto-conical peripheral groove 940 of the housing 914 and causes the
ferrule connecting means 910 to be secured to the housing 914 while
shielding the electrically conductive peripheral portion 912 of aluminum
tube 20.
Ferrule connecting means 910 is suitably made of a strong, resilient,
electrically insulating plastic material such as polypropylene or
polycarbonate. In a preferred embodiment, the ferrule is a colored
plastic, with the color utilized to identify the type of instrument of
which it is a part. For example, a blue ferrule might identify a Maryland
dissector, while a red ferrule might identify a single acting scissors.
Regardless of color, the ferrule is installed by being moved slidably
along shrink wrap 20 in the direction indicated at 945. When the ferrule
means 910 is moved in the direction indicated, at some point, the portion
of the frusto-conical projection 938 located adjacent wall 936 resiliently
deforms outwardly to pass over rim 934 of rigid plastic housing 914. After
wall 936 passes wall 922, the frusto-conical projection 938 snaps back
into a mating engagement with groove 940 of the rigid plastic housing 914.
In this mated position, the electrically insulating ferrule connecting
means 910 overlaps peripheral electrical conductive portion 912 of
aluminum tube 20 as well as substantial portions of the electrically
insulating shrink wrap 20 and the electrically insulating housing 914. In
this manner, the ferrule connecting means 910 ensures that the possibility
of short circuiting and electrical disruption is eliminated.
The preferred laparoscopy instruments of the invention are preferably
assembled in the following fashion. The knurled portion 34 of the clevis
30 of the invention is inserted into the aluminum tube 15 which had been
previously insert molded in the fixed handle portion 914, 410 of the
actuating means 50. The aluminum tube 15 is crimped over the knurls 37 to
effect mating. Shrink wrap 20 is then applied over the aluminum tube 15
and end-cut at grooves 380 in the arms 36 of the clevis 30. Ferrule 910 is
slid over the distal end of the aluminum tube 15, up over the end of the
housing 914, and snapped into place, thereby providing complete
insulation. The rod 60, staples 110, 112, and end effectors (e.g. 90, 92)
are assembled, with the staples coupling the rod to the end effectors. The
rod is slid through the clevis and down the aluminum tube, until the end
effectors are located between the arms of the clevis. When the holes in
the proximal end of the end effectors (e.g. 96, 98) are lined up with the
through-holes 39 in the arms of the clevis, the rotation post 45, which
may either be integral with the clevis, or a separate post or nail, is
inserted through the holes in the end effectors, and secured in the holes
of the clevis arms such as by tapping. At this point, all that remains to
be assembled is the actuating means 50. To assemble the actuating means, a
cross pin 440 is inserted in handle 420. Handle 420 is then arranged such
that the push rod 60 which extends out of the fixed handle portion will
extend through the cross pin 440. With rod 60 in the cross pin 440, handle
420 is lined up with handle 410 such that the handle rotation pivot pin
430 can be inserted. With pivot pin 430 in place, and with the end
effectors in the closed position, set screw 441 is tightened into the
cross pin until it bites into rod 60, thereby holding rod 60 in place
relative to cross pin 440.
There has been described and illustrated herein a disposable laparoscopic
instrument. While particular embodiments of the invention have been
described, it is not intended that the invention be limited exactly
thereto, as it is intended that the invention be as broad in scope as the
art will permit. Thus, while particular end effectors were disclosed, it
will be appreciated that other end effectors such as, e.g., duck-bill
graspers, duck-bill dissectors, atraumatic graspers, and traumatic
(rat-tooth) graspers, could be utilized. Also, while various materials
were described as being preferred for various parts, it will be
appreciated that other materials could be utilized. By way of example
only, and not by way of limitation, while the tube and clevis are
preferably made from aluminum alloys, with the clevis being harder than
the tube, if desired, the tube could be harder than the clevis. In such a
situation, rather than crimping the tube over the clevis, the clevis could
be welded or press fit into the tube. Therefore, it will be apparent to
those skilled in the art that other changes and modifications may be made
to the invention as described in the specification without departing from
the spirit and scope of the invention as so claimed.
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