U.S. patent number 3,659,608 [Application Number 04/884,861] was granted by the patent office on 1972-05-02 for snap-acting surgical lancet.
This patent grant is currently assigned to Damon Corporation. Invention is credited to Wesley G. Perry.
United States Patent |
3,659,608 |
Perry |
May 2, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
SNAP-ACTING SURGICAL LANCET
Abstract
A new snap-acting surgical lancet has a spring urging the
forward ends of two opposed arms apart. A lower of the two arms
carries a downwardly protruding lancing blade. Latching elements on
the two arms hold them cocked with their front ends close together,
and are releasable to allow the spring to snap the end of the lower
arm downward, carrying the blade downward to lance the skin. A stop
carried on one arm engages the other arm to limit this snap-apart
travel of the arm ends. A single piece of spring material is
readily formed to provide all of the foregoing structure, thereby
providing a one-piece lancet.
Inventors: |
Perry; Wesley G. (Wayland,
MA) |
Assignee: |
Damon Corporation (Needham
Heights, MA)
|
Family
ID: |
25385583 |
Appl.
No.: |
04/884,861 |
Filed: |
December 15, 1969 |
Current U.S.
Class: |
606/182;
30/366 |
Current CPC
Class: |
A61B
5/150442 (20130101); A61B 5/15113 (20130101); A61B
17/32093 (20130101); A61B 5/150022 (20130101); A61B
5/15142 (20130101); A61B 5/15117 (20130101); A61B
5/150175 (20130101); A61B 5/150839 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); A61b 017/32 (); A61b
017/34 () |
Field of
Search: |
;30/164.5,164.6,164.7,164.8,366,367,368 ;83/586
;128/253,305,314,315,316,329,330,333 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pace; Channing L.
Claims
Having described the invention, what is claimed as new and secured
by Letters Patent is:
1. A surgical lancet comprising
A. a first, handle-forming, elongated member having front and back
ends,
B. a second, blade-carrying, elongated member having front and back
ends,
C. a spring element
1. connected between said first and second members and disposing
them substantially lengthwise of each other with said front ends
opposite each other and said back ends opposite each other,
2. constraining said members from lengthwise movement relative to
each other and,
3. resiliently urging said members to snap from a cocked position
in which said front ends are proximal to each other to a lancing
position in which said front ends are further removed from each
other in a direction transverse to the elongation of said second
member,
D. a lancing blade carried on said second member adjacent the front
end thereof and protruding therefrom in the direction in which said
front end of said second member moves relative to said first member
in moving from said cocked position to said lancing position,
and
E. releasable latching means for holding said members in said
cocked position and releasable to allow said spring element to snap
the front end of said second member away from said first member and
into said lancing position.
2. A surgical lancet as defined in claim 1 further comprising a
stop member carried on one of said first and second members and
extending therefrom to beyond the other of said members and
interferingly engaging said other member when said members are in
said lancing position to limit the distance the front ends of said
members snap apart in moving from said cocked position into said
lancing position.
3. A surgical lancet as defined in claim 1 further comprising
A. a leg member extending from said first member in the direction
toward said second member, and
B. a pressure foot carried on said leg member and disposed beyond
said second member relative to said first member and adjacent the
protrusion of said blade from said second member when said second
member is in said lancing position.
4. A lancet as defined in claim 3 in which said pressure foot is
further disposed opposite said second member in the direction away
from said first member to block the travel of the front end of said
second member beyond said lancing position.
5. A lancet as defined in claim 1 in which said latching means
includes
A. an arm extending from said second member in the direction
opposite to said blade and, when said members are in said docked
position, to beyond said first member, and
B. a latch element on said arm and engageable with the side of said
first member facing away from said second member to hold said
members in said cocked position, said arm and latch element being
moveable to release said latch element from said engagement with
said first member.
6. A lancet as defined in claim 5 in which
A. said first member has an aperture therethrough, and
B. said arm is disposed to carry said latch element through said
aperture when said first and second members are in said cocked
position and into latching engagement with said side of said first
member.
7. A surgical lancet as defined in claim 1 in which said latching
means includes
A. a leg member extending from said first member adjacent the front
end thereof in the direction toward said second member, and
B. latching shoulder means on said leg member for releasably
engaging said second member when in said cocked position.
8. A lancet as defined in claim 7 further comprising a stop member
protruding from said leg member beyond said second member relative
to said first member and limiting the travel of the front end of
said second member away from said first member beyond said lancing
position.
9. A surgical lancet comprising
A. a folded U-shaped strip spring having first and second elongated
members joined at said fold and resiliently deformable to allow
portions of said members remote from said fold to move toward each
other into a cocked position and resiliently urging said portions
apart into a lancing position,
B. a lancing blade protruding from said second member at said
portion thereof and in the direction away from said portion on said
first member,
C. releasable catch means carried with one of said first and second
members for holding said members with said portions thereof in said
cocked position and movable to release said members thereby
allowing said portions thereof to spring apart into said lancing
position, and
D. stop means carried with one of said first and second members and
engaging the other member to limit the separation of said portions
from each other beyond said lancing position.
10. A lancet as defined in claim 9 in which said strip spring
further comprises a leg member depending from said portion of said
first member toward said second member and carrying said stop means
thereon.
11. A lancet as defined in claim 9 in which said stop means is
carried on said first member and underlies, when said portions are
in said lancing position, said second member closely adjacent the
protrusion of said blade from said second member, thereby to form a
pressure foot.
12. A surgical lancet comprising:
A. a loop of strip spring having disconnected ends and having, in
succession about said loop from one said end thereof,
1. a stop foot,
2. a leg member substantially perpendicular to said stop foot,
3. a handle member extending substantially perpendicularly from
said leg member along the same direction as said stop foot,
4. a blade-carrying member extending substantially lengthwise of
said handle member towards said leg member with a terminal portion
thereof overlying and normally being resiliently urged against the
side of said foot opposite said handle member,
B. a lancing blade carried on said blade-carrying member and
protruding therefrom away from said loop and from the juncture of
said leg and handle members, and
C. first and second latching means carried on said handle and
blade-carrying members respectively, said latching means
automatically engaging one another when said terminal portion of
said blade-carrying member and said handle member are moved
proximal to each other from said normal position and manually
disengageable to allow said terminal portion of said blade-carrying
member to snap into said normal position.
13. A surgical lancet as defined in claim 1
A. in which said latching means includes a leg member
1. extending from said first member adjacent the front end thereof
in the direction toward said second member,
2. having a first end at the juncture thereof with said first
member,
3. having a second end disposed, at least when said first and
second members are in said cocked position, beyond the side of said
second member facing away from said first member, so that said
second end can bear against a surface to be lanced,
4. said leg member having at least a portion thereof between said
ends which is further removed than said first end thereof from said
back end of said first member, and
B. in which said latching means further includes latching shoulder
means on said portion of said leg member for releasably engaging
said second member when in said cocked position, said latching
shoulder means
1. including a protrusion extending longitudinal to the elongation
of said second member between said front end and said back end
thereof,
2. engaging with said protrusion said front end of said second
member to provide said latching engagement,
3. being displaced away from said front end of said second member,
thereby to release said latching engagement, in response to a force
on the front end of said first member directed toward the front end
of said second member and opposed by a reaction force directed on
said leg member from said second end thereof to said first end
thereof.
14. A surgical lancet comprising
A. a first, handle member having front and back portions,
B. a second, blade-carrying member having front and back ends,
C. a spring element
1. connected between said first and second members and disposing
them substantially lengthwise of each other with said front end and
front portion lengthwise adjacent each other and with said back end
and back portion lengthwise adjacent each other,
2. constraining said members from lengthwise movement relative to
each other, and
3. resiliently urging said members to snap from a cocked position
in which said front end and front portion are proximal to a lancing
position in which said front end and front portion are distal,
D. a lancing blade carried on said second member adjacent the front
end thereof and protruding therefrom in the direction in which said
front end of said second member moves relative to said first member
in moving from said cocked position to said lancing position,
E. releasable latching means for holding said members in said
cocked position and releasable to allow said front end of said
second member to snap into said lancing position, and
F. a foot member mounted with said first member and disposed
opposite, in said first direction, to said front end of said second
member; said foot member interferingly engaging said second member,
when in said lancing position, adjacent the protrusion of said
lancing blade therefrom to fix its location in said lancing
position.
15. A surgical lancet comprising
A. a handle member,
B. a presser foot on the handle member,
C. a lancing blade,
D. an elongated blade-carrying member
1. having front and back portions and connected at said back
portion to said handle member to extend lengthwise thereof,
2. having a spring section constituting at least a portion thereof
between said connection to said handle member and said front
portion, said spring section rendering said front portion movable
relative to said handle member between a cocked position where said
front portion is retracted from said presser foot and a lancing
position where said front portion abuts said presser foot, the
resiliency of said spring section urging said front portion into
said lancing position, and
3. carrying said lancing blade at said front portion thereof
disposed to be retracted from said presser foot in said cocked
position and to protrude therefrom in said lancing position,
and
E. releasable latching means for holding said front portion of said
blade-carrying member in said cocked position and releasable for
allowing said front portion to assume said lancing position.
Description
BACKGROUND OF THE INVENTION
This invention relates to a surgical lancet for slicing dermal
tissue to sever plural capillaries and thereby produce a flow of
blood for collection for analysis and like purposes. In particular,
the invention provides such a lancet that is simply constructed to
be of such low cost as to be disposable after use with a single
patient. The lancet is diminutive in size so as not to excite fear
or other anxiety in the patient. The lancet is used in a manner
that allows it to be positioned at the desired site of incision
before forming the incision.
Dermal puncture lancets of many constructions are known, including
the seemingly simple pin-like blade mounted in a plastic handle and
used with a stabbing motion. A drawback of this type of lancet is
that a certain skill is required to aim the pin to the point of the
desired incision. A misplaced puncture can, for example, bruise the
patient's bone, which is most undesirable.
An older dermal puncture instrument has a hollow hand-held barrel
containing a pointed rod that is spring loaded to protrude out of
the end of the barrel. The rod is retractable within the barrel,
compressing a spring, and latchable in this position. Depression of
a button on the barrel releases the rod and the spring drives it
forward, driving the blade beyond the end of the barrel to make the
incision.
This lancet construction is too costly to dispose after each use,
but is of relatively complex structure so as to made sterilizing or
other pathogen-free cleansing difficult. Also, repeated use often
requires that the blade be sharpened, which is inconvenient.
U.S. Pat. Nos. 16,478; 16,479; and 2,646,799 disclose other prior
lancet constructions. The former two patents disclose relatively
complex structures that would be too costly to be disposed after
each use. The lancet of the latter patent requires the operator to
manually depress the blade to make the desired cut.
Accordingly it is an object of this invention to provide an
improved lancet for making a dermal puncture for obtaining a blood
sample.
Another object of the invention is to provide such a lancet that
can be made at such a low cost that it can reasonably be discarded
after each use. A lancet meeting these objectives can be furnished
to the medical practitioner in a sterile enclosure and then
disposed after a single use. This ensures that the lancet is
sufficiently sharp to form a clean incision and is truly
pathogen-free to protect the patient from infection and the
practitioner from malpractice liability.
It is another object of the invention to provide a surgical lancet
that can be prepositioned at the desired site of incision prior to
forming the incision.
It is also an object of the invention to provide a lancet of the
above character that operates with a snap-acting lancing
operation.
A further object is to provide a lancet of the above character that
is diminutive in appearance and hence can be used with pediatric
and geriatric patients, as well as others, without inciting fear or
other traumatic anxiety.
Other objects of the invention will in part be obvious and will in
part appear hereinafter.
SUMMARY OF INVENTION
The present surgical lancet can be formed from a single strip of
spring material to have a loop-like shape with opposed handle and
blade-carrying arms and with a spring joining the back ends of the
arms and urging the front ends apart. The arms carry a releasable
latch for holding them in a cocked position where the spring is
taught, and carry a stop for limiting the separation of the arm
front ends when the latch is released and the spring snaps the arms
apart.
This lancet structure is easily sterilized, inexpensive enough to
be discarded after a single use, and easily operated with minimum
skill to position and orient the incision as desired. Further, a
portion of the lancet loop structure is normally pressed against
the tissue immediately adjacent the point of incision, thereby
dulling the nerves of the patient so that the incision is formed
with minimal discomfort.
The invention accordingly comprises the features of construction,
combinations of elements and arrangement of parts exemplified in
the constructions hereinafter set forth, and the scope of the
invention is indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the
invention, reference should be had to the following detailed
description taking in connection with the accompanying drawings, in
which:
FIG. 1 is a pictorial representation showing a lancet embodying the
invention positioned on the finger of a patient and ready for
release to make an incision;
FIG. 2 is a side elevation view of the lancet of FIG. 1 in the
lancing position;
FIGS. 3 and 4 are side elevation views of another lancet embodying
the invention and showing it respectively in cocked and lancing
positions; and
FIG. 5 is a top plan view, partly broken away, of the lancet shown
in FIG. 4.
DESCRIPTION OF ILLUSTRATED EMBODIMENTS
FIG. 1 shows a lancet 10 according to the invention in a cocked
position and positioned on a finger in which a dermal puncture is
to be cut for obtaining a sample of blood. The lancet is operated
by pressing down on it slightly in the direction of arrow 32 and by
then moving a release element in the forward direction as indicated
with arrow 28. Upon being released, the arms of the lancet snap
apart to the lancing condition shown in FIG. 2, where the blade
protrudes downward to make the desired incision.
More particularly, FIG. 1 shows a one piece lancet 10 formed by
folding a strip of spring material to provide a handle arm 12
oppositely above a blade-carrying arm 14 and with the fold 16
joining the two arms together at back ends thereof. At the front
end of arm 14, the spring strip is bent transversely to the arm to
form a downwardly protruding lancing blade 18 and an upwardly
extending latch arm 20. The latch arm has, in upward succession, a
wide section 20a, a narrow section 20b, and an intermediate width
top section 20c. The juncture between sections 20b and 20c forms a
latching shoulder, and the top section 20c also forms a release
element.
As also shown in FIG. 1, at the front end of the handle arm 12 the
spring strip is bent to form a downwardly depending leg 22
terminating in a foot 24 that extends longitudinally of the arms 12
and 14 and is disposed below the arm 14.
The handle arm 12 has a latching aperture 26 therethrough adjacent
the front end of the arm. The aperture has a wide section 26a, the
forward end of which is essentially at the juncture of the handle
arm 12 and leg 22 so that when the arms 12 and 14 are pressed
together to the position shown in FIG. 1, the top section 20c of
the latch arm can slide along the leg 22 directly into the aperture
section 26a. The aperture 26 further has a narrow section 26b
extending to the back along arm 12 from the wide section 26a. The
wide aperture section 26a is of sufficient width for the top
section 20c of the latch arm to pass therethrough, and the aperture
section 26b is narrower than the latch arm top section 20c but
wider than the latch arm narrow section 20b.
With further reference to FIGS. 1 and 2, the sections of the arm 20
are angled relative to the front end of the blade-carrying arm 14
so that when the arms 12 and 14 are pressed together, the wide
section 20c of the upstanding arm passes through the aperture wide
section 26a. With further pressing of the arms 12 to 14 together,
the latch arm section 20b passes through the aperture 26 and snaps
back into the aperture section 26b. Hence, if the arms are now
released so that the resiliency of the fold 16 urges the front ends
of arms 12 and 14 apart, the shoulder noted above engages the sides
of the aperture section 26b. This engagement holds the arms 12 and
14 in the cocked position shown in FIG. 1, with their front ends
relatively proximal to each other.
The lancet remains securely cocked in this position. However the
lancet is released simply by urging the top, release element,
section 20c of the latching arm forward, in the direction indicated
with arrow 28 in FIG. 1. This disengages the latching shoulder of
the arm 20 from the aperture section 26b and thereby releases the
front end of arm 14 so that the spring action of fold 14 snaps the
front ends of arms 12 and 16 apart, to the position shown in FIG.
2. With the handle arm 12 of the lancet held by the operator, this
snap-apart action drives the blade 18 downward, thereby cutting the
desired incision.
It should be noted that the illustrated lancet 10 has an elongated
ridge-like stiffening rib 34 extending forward on the handle arm 12
from adjacent the fold 16. The rib maintains the arm 12 essentially
straight, so that it does not bend appreciably when the lancet is
cocked. Hence, the rib constrains more of the bending to the fold
16 than would occur where the arm 12 were only equally as stiff as
the fold 16. As a result, the blade 18 undergoes less longitudinal
movement, i.e. along the direction in which the arms 12 and 14
extend, when the lancet opens from the cocked position to the
lancing position. Where desired, the blade carrying arm 14 can be
similarly stiffened.
As also shown in FIG. 1, the foot 24 of the lancet extends only
part way across the width of the spring strip and the blade extends
only across the portion of the strip width where the foot does not
extend. The illustrated embodiment provides this arrangement by
having a notch 30 through the foot through which the blade 18
passes when in the lancing condition of FIG. 2.
The foot 24 serves two functions in the lancet 10. One is to stop
the travel of the arms 12 and 14 as they snap apart to the lancing
position. This function is readily attained by having the foot 24
block the movement of the front end of the blade-carrying arm 14 as
it snaps away from the arm 12. It will also be noted that the depth
of the cut which the lancet makes is positively limited to the
length of the blade 18 protruding below the stop 24, as shown in
FIG. 2.
The other function of the foot 24 is to provide a pressure pad
directly adjacent the site of the incision which the blade 18
makes. In use, the operator applies a slight downward pressure, in
the direction of arrow 32, and the lancet leg 22 carries this
pressure to the foot 24 which accordingly presses against the
patient's skin closely about the site of the incision. As is known,
this pressure desensitizes the dermal nerves of the patient and
hence the patient feels hardly any discomfort when the lancet is
released from the cocked position and makes the desired
incision.
It will also be seen from the roughly approximate relative sizes in
FIG. 1 of the finger and of the lancet that the lancet 10 is of
such diminutive size that the patient in truth hardly notices it,
especially when the handle arm 12 is held between the thumb and
middle finger of the operator and his forefinger is placed on the
top of the arm 12 ready to urge the latch arm top section 20c
forward in the direction of arrow 28. This small size of the lancet
makes it particularly acceptable for use with children, the
elderly, and others likely to be distraught by the sight of a
larger surgical instrument such as the hollow barreled lancet
discussed hereinabove.
Turning to FIGS. 3,4 and 5, the present folded spring strip
construction for a surgical lancet can be applied to a lancet 40
that is even simpler than the lancet 10 of FIGS. 1 and 2. As with
the lancet 10, the lancet 40 has a strip of spring material folded
to provide a handle arm 42 and a blade carrying arm 44 joined
together by a resilient spring fold 46; the arms 42 and 44 and fold
46 together having a generally U-shape. A leg 48 depends from the
forward end of the handle arm 42 and has at its base end a foot 50
that serves the same stop and pressure foot functions as the foot
24 of the lancet 10. A blade 52 protrudes downwardly from adjacent
the front end of the lancet arm 44; the blade illustratively is
formed by stamping it from the strip material in the arm 44 as
shown in FIG. 5. When the lancet is in the lancing condition, FIGS.
4 and 5, the blade is disposed next to the edge of the foot 50.
With this construction, the foot 50 can extend the full width of
the spring strip as also shown in FIG. 5.
FIG. 3 shows the lancet 40 in a cocked position and FIG. 4 shows it
in the lancing position where the foot 50 blocks the front end of
the blade-carrying arm 44 from traveling further from the handle
arm 42.
The latching structure for the lancet 40 is simply a detent 54
protruding inward, i.e. into the loop shape of the lancet 40, on
the leg 48. The forward edge of the blade-carrying arm 44 is
arranged to rest on the shoulder formed by the detent as shown in
FIG. 3.
The lancet is released from this cocked position simply by pressing
downward on it, at the position and in the direction indicated with
arrow 56 in FIG. 3. The geometry of the lancet is such that this
force, combined with the reaction force developed in the upward
direction at the foot 50, deform the lancet slightly to move the
leg 48 and the forward edge of the arm 44 apart, thereby releasing
the arm 44 from the detent 54 so that the arm 44 snaps down against
the foot 50 under the resilient spring force of the fold 46. More
specifically, as shown in FIGS. 3 and 4, the leg 48 extends from
arm 42 and the lower end of the leg is below arm 44. The leg 48
mounts the detent 54 spaced from the fold beyond (ie. to the left
in the FIGURES) the juncture of the leg and arm 42. Hence when the
arm 42 and foot 50, at the lower end of the leg, are pressed
together, the detent 54 is displaced further from the fold 46,
thereby releasing the free end of arm 44.
The lancet 40 is illustrated with a second detent 58 disposed lower
on the leg 48 than the detent 54, the holding the lancet cocked
with a lesser snap-apart force. The detents 54 and 58 are
preferably wedge-shaped protrusions from the leg 48 as seen in the
side views of FIGS. 3 and 4 so that the front edge of the
blade-carrying arm 44 easily slides upward into the latching
position when the arms 42 and 44 are pressed together.
The invention thus provides a truly disposable but yet
spring-driven snap-acting surgical lancet. Further, the lancet is
prepositioned at the exact site desired for the puncture, and it
desensitizes the puncture site. These features ensure the patient
of the utmost in safety, even with relatively unskilled medical
personnel and the minimum of discomfort.
It will thus be seen that the objects set forth above, among those
made apparent from the preceding description, are efficiently
attained and, since certain changes may be made in the above
constructions without departing from the scope of the invention, it
is intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the scope of the invention
which, as a matter of language, might be said to fall
therebetween.
* * * * *