Note: Descriptions are shown in the official language in which they were submitted.
1036~6
In Canadian Patent No. 953,997 issued September 3,
1977 to United States Surgical Corporation, there is disclosed a
surgical stapler for joining the disunited skin of a patient. The
surgical stapler disclosed in this application employs a staple-
carrying cartridge comprising an anvil adapted to lie flush with
the skin, a plurality of staples which are to be folded around
the anvil, and a pusher for ejecting and bending the staples
around the anvil. The surgical stapling instrument adapted to
accept the staple-carrying cartridge in this application is pow-
ered by a pressurized gas. Later developments of the gas-powered
stapler and cartridge for applying surgical staples to external
skin and internal fascia are disclosed in U.S. Patent No. 3,662,939
issued May 16, 1972 to United States Surgical Corporation.
Although these gas-powered instruments represent a
marked advanced over the state of the art, there are certain dis-
advantages associated with the use of gas-powered units of this
type. One of the obvious disadvantages is the necessity for re-
placing the gas cartridges after their contents have been exhaust-
ed, and a second is the inconvenience associated with storing and
maintaining a supply of these cartridges. Also, the powering
mechanism is complex, is hence somewhat costly, and comprises
numerous close-tolerance elements which tend to be susceptible
to malfunction. For these and other obvious reasons, it would
be advantageous to have a simple surgical stapling instrument
adapted to accept staple-carrying cartridges of the type disclosed
in the above patent application and patent, but which is powered
manually and without the intervention of a gaseous medium and
the disadvantages associated therewith.
Accordingly, it is a broad object of the present in-
vention to provide a surgical stapling instrument for staplingthe disunited skin or fascia of a patient which is manually pow-
ered and wholly operated by mechanical means. ~-
2-
.~
`
036~
It is another object of the present invention to provide
a surgical stapler in which the staple-carrying cartridge is
mounted so that it is rotatable relative to the hand-held main
body portion of the instrument so that the staples can be
applied at any angle without the necessity for rotating th~
hand-held portion of the instrument.
It is yet another object of the present invention to
provide a surgical stapler with means for ensuring that the
staple-advancing drive means of the instrument is activated only
once in each stapling operation.
Another object of the invention is to provide means for
preventing a driving stroke of a surgical stapler absent the
association with a staple-carrying cartridge.
It is yet a further object of the present invention
to provide means for preventing the insertion of a staple-
carrying cartridge into the sur~ical stapler until the driving
mechanism of the stapler has been returned to its initial
position.
It is still a further object of the present invention
to provide a surgical stapler with means to alert the surgeon
when a staple has been advanced into the ready position and is
about to be ejected and formed.
hese and other objects of the invention, as well as
-~ many of the attendant advantages thereof, will become more
readily apparent when reference is made to the following
description taken in conjunction with the accompanying drawings.
In accordance with the invention in one aspect there is
provided a surgical stapling instrument for applying sterilized
staples to the disunited skin or fascia of a patient for
effecting a joining of the skin or fascia, the instrument
- adapted to associate with a staple-carrying cartridge that
houses a plurality of staples therein, and includes a pusher
,~ .
,, " 1036~6
element slidably mounted therein for ejecting staples from said
cartridge and for forming said staples around an anvil means,
and means for advancing said staples in said cartridge, said
surgicai stapling instrument comprising: a main body portion;
means for mounting said staple-carrying cartridge on said main
body portion; drive means to activate said staple-advancing
means and for driving the pusher element forward to eject a
staple from the staple-carrying cartridge and to form said staple
around an anvil means; said instrument being manually powered,
and further comprising trigger means for transmitting a manually
applied force to said drive means to power said drive means.
In accordance with the invention in a further aspect there
is provided a surgical stapling instrument for applying sterilized
staples to the disunited skin or fascia of a patient for effecting
a joining of the skin or fascia, the instrument adapted to
associate with a staple-carrying cartridge having anvil means
at one end thereof and adapted to house a plurality of staples
therein, a pusher element slidably mounted therein for ejecting
staples from said cartridge and for forming said staples around
said anvil means, and means for advancing said staples in said
cartridge, said surgical stapling instrument comprising: a main
body portion; means for mounting said staple-carrying cartridge
~- on said-main body portion; drive means to activate said staple-
-~ advancing means for driving the staples toward said anvil means
and for driving the pusher element forward to eject a staple
from the staple-carrying cartridge and to form said staple around
said anvil means; said instrument being manually powered, and
further comprising trigger means for transmitting a manually
applied force to said drive means to power said drive means.
A typical embodiment of the surgical stapling instrument
~ generally comprises a main body portion having a nose portion
rotatably mounted therein and adapted to receive and mount a
staple-carrying cartridge. The nose portion of the stapler houses
. the drive means -3a-
~0~6.~86, . l
for advancing and forming the staples. A pusher-activating
means for driving the pusher element of the staple-carrying car-
tridge to eject and form the staples around the anvil means of
the cartridge comprises a thrust bar slidably mounted for recipro-
cative movement in the nose portion of the stapler. The thrust
bar is attached to and adapted to move with a collar element
slidably mounted on the nose portion of the stapler. A trigger
means comprises a handle which is pivotally mounted on the main
body portion of the stapler and has means for engaging the collar
element so that the thrust bar is moved forward by squeezing the
trigger. A return spring attached to the trigger and to the main
body portion of the stapler functions to return the thrust bar to
its initial position after the thrust stroke of the bar has been
completed.
The drive means to activate the staple-advancing means
~ in the staple-carrying cartridge for driving the staples toward
; the anvil comprises pinion gears and pinion shafts also housed
; within the nose portion of the stapler. The teeth of the pinion
gears mesh with the teeth of a main gear which is adapted to
rotate in unison with a ratchet. The main gear and ratchet are
rotatably mounted in the rear nose portion of the stapler. An
index pawl pivotally attached to the thrust bar and operatively
associated with the ratchet causes the ratchet, main gears, and
pinions to rotate when the thrust bar is initially moved forward
and thus activates the staple-advancing means in the cartridge.
As was the case in the above-mentioned application and
patent, it is desirable to rotate the particular drive screws of
the staple-carrying cartridge 360 each time a staple is being
ejected by first overdriving and then return-driving the screws.
Accordingly, and similar to the gear boxes disclosed in the above-
mentioned application and patent, the drive means for advancing
1036~86
advancing staples of the present invention is adapted to be over-
driven and then returned to a position wherein the drive screws
of the cartridge are rotated exactly 360. The return movement
of the staple-advancing drive means is accomplished by a spring
pawl which cooperates with the above-mentioned ratchet. This
spring pawl also functions as a stop, preventing excessive
return rotation of the ratchet.
Means are also provided for preventing more than one
staple from being placed in the ready position of the staple-
carrying cartridge during the stapling operation. This meanscomprises a clutch means which prevents the return of the thrust
bar to its initial position until it has completed a full stroke,
thereby ejecting a staple from the staple-carrying cartridge.
The clutch means includes a cam block mounted in the forward end
of the nose portion of the stapler and having an inclined sur-
face facing the thrust bar. The forward end of the thrust bar
passes through the cam block and operatively engages a cylindri-
cal roller positioned between the thrust bar and the inclined
surface of the cam block. The cam block houses a spring-biased
wedge which cooperates with the cylindrical roller. The coopera-
tion between these elements is such that the cylindrical roller
prevents the thrust bar from being returned to its initial posi-
tion until it has completed a full driving thrust movement.
Means are further provided for preventing the forward
movement of the thrust bar until a staple-carrying cartridge has
been mounted on the stapler. This means comprises a cartridge
interlock housed in the forward end of the nose portion of the
stapler and spring biased into a position such that it blocks
the forward movement of the thrust bar until a cartridge is prop-
erly mounted. In its initial position, the forward end of thethrust bar abuts the rear face of the cartridge interlock. When
the staple-carrying cartridge is mounted, the cartridge interlock
--5--
1036~6
is forced upward by the staple-carrying cartridge, thereby regis-
tering an opening in the cartridge interlock with the forward
end of the thrust bar such that the thrust bar is capable of
being moved forward and driving the pusher element of the staple-
carrying cartridge to eject and form the staples.
The forwardmost staple in the staple-carrying cartridge
is advanced into the ready position during the initial stage of
the forward thrust stroke of the thrust bar. At this point, and
with the thrust bar partially advanced, it is possible to remove
the staple-carrying cartridge from the stapler. Under these cir-
cumstances, the clutch means prevents the thrust bar from return-
ing to its initial position. Accordingly, the thrust bar must be
fully advanced before it will be automatically returned to its
initial position. The surgeon or his attendant may not remember
to follow this procedure, however, and may attempt to mount a
staple-carrying cartridge in the stapler while the thrust bar is
in this partially advanced position. This procedure could result
in jamming the drive mechanisms of the staple-carrying cartridge
or other undesirable mechanical difficulty.
To prevent such jamming, means are provided for pre-
venting a cartridge from being mounted unless the thrust bar has
returned to its initial position. This means comprises a car-
tridge stop lock mounted in the forward end of the nose portion
of the stapler. When the thrust bar is in its initial position,
the cartridge stop lock is oriented so that a staple-carrying
cartridge can be easily locked in the stapler. If the thrust
bar is not in its initial position, however, but rather is in a
partially advanced position, the cartridge stop lock is spring
biased into a blocking position so that a staple-carrying car-
tridge cannot be fully mounted in the stapler.
While the initial movement of the trigger advances the
staples and the intermediate movement readies the cartridge for
10~6
the stapling operation, only the final stages of trigger movement
effect the ejection and formation of a staple. Accordingly, it
is desirable to alert the surgeon to the fact that a staple is
about to be ejected so that the surgeon can be sure that the
instrument is properly positioned. In fact, the inventive instru-
ment could be operated remote from the patient until the last
stage of trigger movement, and only then oriented in readiness
for a stapling operation. As part of the present invention, the
stapler is provided with a spring-biased wedge housed in the nose
portion of the stapler which snaps into a notch on the top sur-
face of the thrust bar with an audible "click" just before a
staple is to be ejected. At the same time, the surgeon will
also feel a slight but noticeable change in the force required
to squeeze the trigger, thus further alerting him to the fact
that a staple is about to be ejected.
As just described, the drive means for advancing sta-
ples in the staple-carrying cartridge and for ejecting staples
therefrom are housed in the nose portion of the stapler which is
rotatably mounted in the main body portion. Since the staple-
carrying cartridge is mounted in the nose portion and rotatable
therewith, it is possible to change the stapling angle of the
stapler by merely rotating the nose portion while maintaining
the hand-held main body portion in a fixed position.
Fig. 1 is a vertical cross section of the surgical
stapling instrument of the present invention;
Fig. 2 is a horizontal cross section taken along line
2-2 of Fig. l;
Fig. 3 is similar to Fig. 2 but shows a portion of
the stapler during the stapling operation;
Fig. 4 is a horizontal, fragmentary view of a portion
of the staple-advancing drive mechanism of the stapler during
the stapling operation;
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~036886
Fig. 5 is a vertical cross section of the stapler look-
ing rearwardly;
Fig. 6 is a side view, partially in section, of the
staple-carrying cartridge mounting portion of the stapler after
the cartridge is mounted and ready for use;
Fig. 7 is a front view of the stapler with the staple-
carrying cartridge mounted and ready for use;
Fig. 8 is a vertical cross section taken along line
8-8 of Fig. 2 and showing the clutch means;
Figs. 9-12 are sequential views showing the operation
of the clutch means during a stapling operation;
Fig. 13 is a vertical cross section taken along line
13-13 of Fig. 2 and showing the position of the cartridge inter-
lock before the staple-carrying cartridge is inserted;
Fig. 14 is similar to Fig. 13 but shows the cartridge
interlock after the insertion of the staple-carrying cartridge
which is shown in phantom lines;
Fig. lS is a vertical cross section taken along line
15-15 of Fig. 2 and showing the position of the cartridge stop
lock before the thrust bar has been advanced;
Fig. 16 is similar to Fig. 15 but shows the cartridge
stop lock after the thrust bar has been partially advanced;
Fig. 17 shows the cooperation between the inclined
surfaces of the thrust bar and cartridge stop lock;
Fig. 18 is a horizontal cross section taken along line
18-18 of Fig. 1 and showing the location plate for locating the
cartridge interlock, cartridge stop lock, and pusher-engaging
portion of the thrust bar;
Fig. 19 is an enlarged view of the rear portion of a
staple-carrying cartridge with its cover removed;
10~6;
Fig. 20 is a cross section taken along line 20-20 of
Fig. 19;
Fig. 21 is a vertical cross section of the front por-
tion of a staple-carrying cartridge; and
Fig. 22 is a view of the front portion of the car-
tridge during the stapling operation with the cover removed.
With reference first to Figs. 1-6, the surgical stapler
of the present invention will be described in general terms.
The stapler shown generally at 10 comprises housing 12 having
main body portion 14 and handle portion 16. Nose portion 20 of
stapler 10 is rotatably mounted in main body portion 14 of hous-
ing 12. Nose portion 20 includes a front section 22 extending
out of housing 12 and adapted to mount staple-carrying cartridge
26. Nose portion 20 further includes a rear section 24 located
inside housing 12 and acting to house the driving means for
advancing, ejecting, and forming staples from the staple-carrying
cartridge. Nose portion 20 is conveniently formed in two parts,
upper and lower, held together by a pair of screws 21 and held
in relative alignment by dowel pins 23 and 25. Staple-carrying
cartridge 26 is shown fitted into nose portion 20 of stapler 10
in Fig. 6.
The staples in staple-carrying cartridge 26 are
advanced, ejected, and formed by mechanical means only and
without the intervention of a gaseous medium. Accordingly, the
power for advancing, ejecting, and forming the staples in car-
tridge 26 comes from the manipulative force supplied to stapler
10 by the surgeon. This force is transmitted to the drive means
of stapler 10 by means of trigger 28 which generally comprises a
handle pivotally attached to housing 12. Pivoting of trigger 28
causes a thrust bar 30, the pusher-activating means, to drive
the pusher element of staple-carrying cartridge 26 forward to
10~6
eject and form a staple around the anvil means. At the same
time, a ratchet 32 and a main gear 34 housed in the rear portion
24 of nose 20 are caused to rotate. Main gear 34, in turn,
rotates a pair of pinion gears 36 and pinion shafts 38 which
associate with the cartridge 26 to advance the staples.
With reference now to Figs. 1 and 5, trigger 28 will
be described. Trigger 28 is pivotally mounted to housing 12 by
means o stud 40 and drive pin 42. Trigger 28 is of appropriate
size and shape to be conveniently gripped by the operating hand
of a surgeon. The trigger includes a rearward extending portion
44 to which is attached one end of a return spring 46. The other
end of return spring 46 is attached to housing 12 and functions
to return trigger 28 and thrust bar 30 to their initial positions
after staple forming has occurred. Trigger 28 is of "Y" shape
and includes a lower hand-engaging portion 48 and an upper force-
transmitting yoke portion 50. Yoke 50 embraces a collar 52
slidingly mounted around the midsection of nose portion 20 and
adapted to rotate therewith. Collar 52 includes a cylindrically-
shaped body member 54 having outwardly and radially extending
flange portions 56 at each end. Yoke 50 is positioned around
cylindrically-shaped body member 54 and between flange portions
56. Shoulder portions 55 and 57 of nose portion 20 limit the
forward and rearward movement, respectively, of collar 52.
Pivoting of trigger 28 results in longitudinally directed force's
being exerted on collar 52 by yoke portion 50 of trigger 28.
Accordingly, when the trigger is activated, collar 52 simulta-
; neously slides along the midsection of nose 20. Also, by this
arrangement, collar 52 is free to rotate relative to trigger 28.
As best seen in Figs. 1, 3, and 17, the means for driv-
ing the pusher element of the staple-carrying cartridge to eject
and form staples comprises thrust bar 30 which includes an elon-
gated central section 58 having a wing portion 60 near the rear
--10--
10368~6
end thereof. A pusher-engaging extension 62 and an inclined
surface 64 are positioned at the forwardmost end of thrust bar
30. Inclined surface 64 is adapted to engage a stop lock mecha-
nism which will be discussed subsequently. Also located near
the front end of thrust bar 30 is an elongated notch 66 which
forms part of the clutch means of the present invention. Locat-
ed near the rear end of thrust bar 30 is a second notch 68 which
engages the forward end of index pawl 70. Thrust bar 30 is
slidingly mounted in nose portion 20 and is adapted to rotate
therewith. As illustrated in Fig. 2, wing portion 60 of thrust
bar 30 lies near the midsection of collar 52, conveniently
formed as two semi-circular parts, and is rigidly attached to
collar 52 by means of bolts 53. Accordingly, thrust bar 30
reciprocates back and forth with collar 52 when trigger 28 is
pivoted, and collar 52 rotates with thrust bar 30 when nose
portion 20 is rotated.
The staple-advancing drive means of the stapler lO is
arranged so that when thrust bar 30 is moved forward, the ele-
ments forming a part of this arrangement are activated; that is,
the forward motion of the pusher-activating element causes the
rotation of the screws of staple-carrying cartridge 26, thereby
advancing the staples. And, as will be more fully described
below, the staples are slightly overdriven during the forward
stroke of thrust bar 30 and are then returned to their proper
positions as will be discussed subsequently.
With reference now to Figs. 1-4, the staple-drive
mechanism will be explained. The index pawl 70 is pivotally
attached to the rear end of thrust bar 30. The transverse base
portion 74 of spring 72 passes through aperture 76 in thrust bar
30, and the inturned end of upstanding leg 78 of spring 72 fits
into one end of an aperture 80 in the rear end of thrust bar 30,
~0368~6
and the inturned end of upstanding leg 82 fits through an aper-
ture 84 in index pawl 70 and then into the other end of aperture
80 in thrust bar 30. An upstanding leg 86 on the forward end of
index pawl 70 fits into notch 68 in thrust bar 30. Notch 68 is
trapezoidal in shape and has inclined surface 88. The combina-
tion of spring 72 and inclined surface 88 of notch 68 allows
index pawl 70 to pivot outwardly.
Index pawl 70 rides along one wall of a six-tooth
ratchet 32 and engages one of the teeth thereof. The index pawl,
pivotally mounted on thrust bar 30, is biased toward ratchet 32
by spring 72. Ratchet 32 is attached to, and rotates with, a
main gear 34. Ratchet 32 and main gear 34 are of unitary con-
struction, as illustrated, and are rotatably mounted in the rear
end 24 of nose portion 20 by means of shaft 90. The teeth of
main gear 34 mesh with the teeth of two pinion gears 36, both
of which are seen in the drawings. Pinion gears 36 are, in t~urn,
attached to pinion shafts 38 which are housed in, and extend
longitudinally through, the nose portion 20 of stapler 10. A
tapered cylindrical body portion 92 on the ratchet 32 and main
gear 34 assembly provides a stop for pinion gears 36 which have
a rear portion 94 which abuts body portion 92 of the ratchet 32
and main gear 34 assembly. (See Fig. l,) This arrangement pre-
vents the pinion shafts from inadvertently being moved out of
their proper longitudinal position.
Thrust bar 30, index pawl 70, and ratchet 32 are
arranged in such a manner that the forward stroke of thrust bar
30 causes ratchet 32 and, accordingly, main gear 34 to move
slightly more than 60. As noted previously, it is desired to
ultimately rotate the screws associated with staple-carrying
cartridge 26 precisely 360 for each staple-driving operation.
The staple-advancing drive means in stapler lO is arranged so
-12-
10~6~6
that for each 60 turn of ratchet 32 and main gear 34, pinion
shafts 38 and the screws in cartridge 26 are rotated 360. How-
ever, to ensure that the staples are advanced a proper amount,
it has been found desirable to overdrive the screws in cartridge
26, and thus the staples, and then to reverse the rotation of
the screws so that ultimately they experience a net 360 rota-
tion. It is for this reason that six-tooth ratchet 32 is rotated
slightly more than 60. It becomes necessary, therefore, to
provide means for returning ratchet 32 to its 60 position. The
ratchet return is brought about by means of spring pawl 96 as
will be discussed subsequently.
With particular reference now to Figs. 2-4, the opera-
tion of the drive means for activating the staple-advancing mech-
, anism of the staple-carrying cartridge and for driving the staples
; toward the anvil will be described. As shown in Fig. 2, thrust
bar 30 is in its initial at-rest position. In this position,
index pawl 70 is in engagement with ratchet 32. Tooth portion
102 of index pawl 70, which is the driving region thereof, is
removed from the nearest tooth on ratchet 32 to allow for slight
"play" before the ratchet 32 is rotated.
When thrust bar 30 moves forward during a stapling
operation, index pawl 70 rotates ratchet 32. Ratchet 32 is
rotated in a clockwise direction as index pawl 70 is moved for-
; ward with thrust bar 30. When ratchet 32 has been rotated
through approximately its desired maximum angle of slightly
greater than 60, the back surface of an advancing tooth of
ratchet 32 engages planar portion 104 near the end of index pawl
70 and forces tooth portion 102 of index pawl 70 out of engage-
ment with ratchet 32. (See Fig. 4.) The maximum angle through
which ratchet 32 is rotated is greater than that needed to
advance each staple one "staple unit". Thus, the staple-
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lQ3~6
advancing drive means is momentarily overdriven; however, this
condition is automatically corrected by spring pawl 96.
Referring now to Figs. 2 and 4, it can be seen that
spring pawl 96 is attached to the rear end 24 of nose portion 20
by means of a pin 97 and comprises an arcuate section terminat-
ing at end 106. Spring pawl 96 contacts ratchet 32 at two
points in its initial position. First, end 106 of spring pawl
96 contacts one of the teeth of ratchet 32. Second, a point on
spring pawl 96 partially between end 106 and the arcuate section
contacts the back surface of the adjacent tooth. Accordingly,
when ratchet 32 is momentarily overdriven, spring pawl 96 is
cammed outward as shown in Fig. 4; however, ratchet 32 is then
immediately returned to an exactly 60 rotation by the biasing
action of spring pawl 96. It will be noted that the counterclock-
wise rotation of ratchet 32 terminates when end 106 of spring
pawl 96 contacts a tooth on ratchet 32. Accordingly, when thrust
bar 30 and index pawl 70 are in the fully advanced position,
shown in solid lines in Fig. 3, spring pawl 96 has the same rela-
tionship to ratchet 32 as it did when thrust bar 30 and index
pawl 70 were in their initial positions illustrated in Fig. 2.
After the forward thrust of thrust bar 30 has been com-
pleted and a staple ejected from the cartridge and formed in the
patient, return spring 46 returns thrust bar 30 to its initial
position. During this phase of operation, the end portion 106
of spring pawl 96 prevents counterclockwise rotation of ratchet
32. At the stage of the thrust bar return stroke when sloped
surface 107 on index pawl 70 contacts a tooth on ratchet 32, the
index pawl begins to be cammed against the force of spring 72.
Further camming action then occurs when the tooth portion 102 of
index pawl 70 contacts the backside of a tooth of ratchet 32.
At this stage, index pawl 70 is pivoted outwardly into the posi-
tion shown in phantom lines in Fig. 3. This outward pivotal
~ .O~B6`'
movement is permitted by spring 72 and the inclined surface 88
of notch 68 of thrust bar 30. Finally, index pawl 70 reassumes
the position shown in Fig. 2. At this point, stapler 10 is ready
for another firing.
As previously stated, it is desirable to alert the sur-
geon to the fact that a staple is about to be ejected and formed
so that the surgeon can be sure that cartridge 26 is properly
positioned to effect a neat suture. This is accomplished by
means of spring-biased means 115 housed in nose portion 20 of
stapler 10. Spring-biased means 115 comprises an upper U-shaped
member 116 which bears against housing 12 and a lower member 117
terminating in a V-shaped point which rides along the top of
i thrust bar 30. Members 116 and 117 are spring biased apart by
a coil spring 118. A notch 119 is provided on the top surface
of thrust bar 30, in alignment with member 117, and is adapted
to receive the V-shaped pointed end of member 117 at a stage of
the stapling operation just before a staple leaves the cartridge.
At this stage, member 117 is snapped into notch 119 on the top
, surface of thrust bar 30 by spring 118 with an audible "click".
Further movement of thrust bar 30 in the forward direction
forces member 117 upward against the force of spring 118 so that
thrust bar 30 can continue its forward movement. This sequence
of events will also cause the surgeon to feel a slight but
noticeable change in the force required to squeeze the trigger,
thus further alerting him to the fact that a staple is about to
be ejected. Member 116 also functions to provide additional
frictional resistance between housing 12 and nose portion 20 to
avoid uncontrolled rotation between nose portion 20 and housing
12 during normal handling and use.
Turning now to Fig. 8, there is illustranted an end
view of a clutch means 120. Clutch means 120 includes a cam
-15-
10~86
block 122 mounted in an opening 124 in forward end 22 of nose
portion 20. Cam block 122 has an inclined surface 126 facing
thrust bar 30 which passes through an opening 128 in cam block
122. Inclined surface 126 is positioned relative to thrust bar
30 such that the spacing 130 between inclined surface 126 and
thrust bar 30 increases in the forward thrust direction of the
thrust bar. A cylindrical cam roller 132 is positioned between
inclined surface 126 of cam block 122 and thrust bar 30. An
elongated wedge pin 134 is housed in an aperture 136 in cam
block 122. The forward end of wedge 134 is "V" shaped and
extends into opening 130 between inclined surface 126 and thrust
bar 30. The wedge pin 134 is spring biased toward thrust bar 30
by means of a spring 138 housed in a recess 140 in cam block 122.
Recess 140 lies perpendicular to aperture 136, and the end of
spring 138, which is hook-shaped, is seated in a bore 142 through
wedge 134. Cam roller 132 lies adjacent elongated notch 66 in
thrust bar 30, and its movement is confined by notch 66 as will
be discussed subsequently. The cooperation between these ele-
ments is such that cylindrical roller 132 prevents thrust bar 30
from being returned to its initial position until completion of
a full thrust stroke.
Figs. 9-12 are sequential views showing the operation
of clutch means 120 during a stapling operation. Turning first
to Fig. 9, thrust bar 30 is shown in its initial position. In
this position, cam roller 132 lies in a shallow cutout 144 posi-
tioned at the forwardmost end of notch 66. Cam roller 132 is
positioned in the narrowest part of opening 130 and at the rear
of clutch means ~20. Spring-biased wedge pin 134 maintains the
cam roller 132 toward the rear end of clutch means 120.
Turning now to Fig. 10, the clutch means 120 is illus-
trated during the forward stroke of thrust bar 30. Cam roller
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132 is shown rotating in a counterclockwise direction. During
this stage of thrust, the surface of cam roller 132 contacts
base 146 of notch 66 and inclined surface 126, and is rotated
by the movement of thrust bar 30. This rotational movement is
permitted since cam roller 132 is, in effect, rotating "downhill"
toward the widest part of opening 130. At the same time, cam
roller 132 bears against spring-biased wedge 134 which restrains
the longitudinal forward movement of cam roller 132 so that the
cam roller is kept in the narrowest part of opening 130.
Still referring to Fig. 10, it can be seen that an
attempted return movement of thrust bar 30 to its initial posi-
tion from its partially advanced position would cause the cam
roller to rotate in a clockwise direction. This movement is not
permitted by clutch means 120, however, since clockwise rotation
of cam roller 132 causes càm roller 132 to "lock" itself between
thrust bar 30 and inclined surface 126 of cam block 122, thereby
preventing all but the slightest movement of thrust bar 30 toward
its initial position. This occurs because cam roller 132 is, in
effect, rotating "uphill" toward the narrowest part of opening
130. Furthermore, cam roller 132 would no longer be bearing
against spring-biased wedge 134.
Turning now to Fig. 11, clutch means 120 is seen at
the forward end of the stroke of thrust bar 30. In this position,
cam roller 132 has been forced to the other side of wedge pin 134
by shoulder portion 148 of notch 66 and lies in the widest region
of opening 130. Once cam roller 132 has so passed wedge 134, it
is housed in an area wider than its diameter and hence is free to
rotate in any direction. Accordingly, cam roller 132 permits
thrust bar 30 to move rearward toward its initial position. A
portion of this operational sequence is shown in Fig. 12 illus-
trating thrust bar 30 during its return stroke. Here, base por-
tion 146 of notch 66 of thrust bar 30 may still lightly contact
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cam roller 132. However, cam roller 132 can freely rotate since
opening 132 is sufficiently wide at this location. Near the end
of the return movement of thrust bar 30 to its initial position,
cam roller 132 is moved into cutout 144 in notch 66 and is then
forced past wedge 134 by shoulder portion 150 of notch 66. Cut-
out portion 144 allows cam roller 132 to be moved past wedge 134
and back to its intial position shown in Fig. 9, without "lock-
ing" before the completion of the return stroke.
Turning now to Fig. 13, there is shown an end view of
a cartridge interlock 152 in its initial blocking position which
prevents the initiation of a thrust stroke until a cartridge is
properly installed on the stapler. Cartridge interlock 152 lies
in blocking and abutting relationship with the forwardmost end
of thrust bar 30 when thrust bar 30 is in its initial position.
Cartridge interlock 152 is positioned in an opening 154 in the
forward end 22 of nose portion 20 and comprises a body portion
156 and leg portions 158. As shown in Fig. 13, cartridge inter-
lock 152 is spring biased into its initial blocking position by a
pair of coil springs 160. In this position, leg portions 158 of
cartridge interlock means 152 extend through openings 165 in a
location plate 164. When a cartridge 26 is mounted on the sta-
pler 10 as shown in Fig. 6, cartridge interlock 152 is forced
upward against the action of springs 160 and into the position
illustrated in Fig. 14. In this position, opening 166 in car-
tridge interlock 152 registers with thrust bar 30 and allows
thrust bar 30 to pass therethrough. Accordingly, cartridge inter-
lock 152 is in the position shown in Fig. 13 when a cartridge is
absent and thrust bar 30 is in its initial position, and i5 in
the position shown in Fig. 14 the remainder of the time.
Referring now to Fig. 15, there is shown an end view of
a cartridge stop lock 170 in its initial position. Cartridge stop
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10~
lock 170 is adapted to prevent the mounting of a staple-carrying
cartridge 26 in stapler 10 unless thrust bar 30 is in its fully
retracted initial position. Cartridge stop lock 170 is mounted
in an opening 172 in forward end 22 of nose portion 20. The car-
tridge stop lock 170 comprises a body portion 174 and leg por-
tions 176. Opening 178 in cartridge stop lock 170 registers with
thrust bar 30 when thrust bar 30 is in its initial position. In
the position shown in Fig. 15, leg portions 176 are retracted
above the bottom of location plate 164. Accordingly, staple-
carrying cartridge 26 can be easily mounted on stapler 10.
As best seen in Fig. 17, the cartridge stop lock 170
is held in its initial position by the inclined surface 64 of
thrust bar 30 which engages a correspondingly inclined surface
180 of cartridge stop lock 170 when thrust bar 30 is in its ini-
tial position. After thrust bar 30 has left its initial position
and is in the thrust or return portion of its storke, cartridge
stop lock 170 is spring biased downward by a pair of coil springs
182 and into the position shown in Fig. 16. In this position,
leg portions 176 extend through openings 184 in location plate
164 and below the bottom thereof to prevent the mounting of
staple-carrying cartridge 26 until thrust bar 30 has been
returned to its initial position. The return of thrust bar 30
to its initial position causes cartridge stop lock 170 to be
forced upward against the action of springs 182 as best shown
in Fig. 17, wherein the initial positions of thrust bar 30 and
stop lock cartridge 170 are shown in phantom lines.
Fig. 18 shows a top view of the location plate 164,
with thrust bar 30 in its initial position. Location plate 164
is housed in an opening 185 in the forward end 22 of nose portion
20. As previously described, location plate 164 has openings
165 and 184 therein for receiving leg portions 158 and 176 of
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~036~6
cartridge interlock 152 and cartridge stop lock 170, respectively.
Location plate 164 also has a longitudinally extending opening
186 which receives pusher-engaging extension 62 and thereby
allows thrust bar 30 to reciprocate.
With reference now to Figs. 6, 7, 19, and 20, the asso-
ciation of the staple-carrying cartridge 26 with the stapler 10
will be explained. Staple-carrying cartridge 26, as can be seen
in the figures, is detachably mounted on nose portion 20. Staple-
carrying cartridge 26 is elongated and has a pair of upwardly
extending spaced tabs 202 at its rear end. The spacing between
tabs 202 is sufficient to allow pusher-engaging extension 62 to
freely slide therebetween, and tabs 202 are dimensioned and posi-
tioned so as to engage surface 203 at the rearmost end of loca-
tion plate 164. Therefore, when tabs 202 engage surface 203,
staple-carrying cartridge 26 cannot be inadvertenetly pulled out
of the nose, and cartridge 26 is fixed against forward movement
during the ~tapling operation.
Staple-carrying cartridge 26 is mounted in stapler 10
by inserting the end of cartridge 26 into opening 110 in nose
portion 20. The rearward end of staple-carrying cartridge 26
engages a leaf spring 108 which ,urges the cartridge 26 upwardly
until tabs 202 are positively locked into their associated inden-
tations in the body of nose portion 20. With cartridge 26 in
this position, the rearward ends 228 of the drive screws 218
forming a part of staple-carrying cartridge 26 are engaged by
slots 39 of pinion shafts 38. The cartridge 26 is removed from
the stapler 10, when exhausted of staples, by reversing the
insertion steps.
With specific reference now to Figs. 19-22, the con-
struction and operation of the staple-carrying cartridge 26 will
be explained. The cartridge 26 is defined by a main body 200 and
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1036~B6
has an anvil 204 at its forwardmost region projecting out as an
extension of the top of cover plate 206. Staple-carrying car-
tridge 26 houses a plurality of staples 208, whose crossbars 210
lie transverse to the length of cartridge 28 and whose points
212 face anvil 204. A pusher element 214 covers staples 208 and
is slidingly mounted within indentations 216 in cover plate 206.
Pusher element 214 is adapted to be engaged by pusher-engaging
extension 62 of thrust bar 30 and serves both to eject staples
208 from the cartridge 26 and to form the ejected staples
around anvil 204.
The means for advancing staples 208 along the length of
cartridge 26 comprises a pair of drive screws 218. Screws 218
are provided with threads 220 for guiding and propelling staples
208 along main body ledges 222 between the lateral walls 221.
The pusher element 214 is guided between the tops of screws 218
and the bottom of cover plate 206, and serves to hold each of the
staples 208 against ledges 222, except during the driving opera-
tion. Then, the forwardmost staple 208 is advanced out of the
screw-guiding threads 220 by means of inclined surfaces 224, at
the forward ends of ledges 222, into the plane of pusher element
214, and is propelled forward, out of the main body portion and
against anvil 204.
Each screw 218 is provided at its rearwardmost end with
an extension 226 fitted at its extremity with a flat projection
228. Screws 218 are threaded so that when they, by means of
projections 226 associating with pinion shaft 38, are rotated
through 360, each staple 208 moves one staple unit. A "staple
unit" is defined as that distance which is required to move the
second staple from its readiness position into a position ready
to be fired. Thus, in Fig. 21, one staple unit is shown at "a".
In operation, while pusher element 214 is moving for-
ward by thrust bar 30, and after the forwardmost staple has been
-21-
raised into the plane of t~e pus ~ pusher element 214 makes
contact with the staple as illustrated in Fig. 22. ~hen, the
staple is ejected and formed in the disunited skin or fascia of
the patient.
Above there have been described specific embodiments
of the present invention. It should be noted, however, that the
above description was given for illustrative purposes only and
that many alterations and modifications may be practiced by those
skilled in the art without departing from the spirit or the scope
of the present invention. It is the intent, therefore, that the
present invention not be limited to the above but be limited only
as defined in the appended claims.
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