US3760809A - Surgical lancet having casing - Google Patents

Abstract

A surgical lancet which has a blade resiliently driven to lance dermal tissue with a snap action has a presser foot that forms a cavity directly over the dermal tissue being lanced and has a cavity-encircling rim for placing against tissue adjacent the lancing site. The rim presses against the dermal tissue to pucker tissue at the lancing site into the cavity and to constrict veinal capillaries adjacent the lancing site. The puckered tissue ensures that the lance is not pressed into bone structure, and the vasoconstriction causes a localized engorgement at the lancing site. The lancet further has a manually holdable casing that forms an aseptic enclosure for the lancing blade, with a septum that the blade pierces in snaping to the lancing position.

Description

[.45] Sept. 25, 1973 SURGICAL LANCET HAVING CASING Stephen P. Campbell, Jr., Brookline, Mass.

[73] Assignee: Damon Corporation, Needham Heights, Mass.

22 Filed: Oct. 22, 1971 21 Appl.No.: 191,948

[75] Inventor:

3,659,608 5/1972 Perry 128/314 Primary ExaminerChanning L. Pace Attorneyl-lerbert W. Kenway et a1.

[57] ABSTRACT A surgical lancet which has a blade resiliently driven to lance dermal tissue with a snap action has a presser foot that forms a cavity directly over the dermal tissue being lanced and has a cavity-encircling rim for placing against tissue adjacent the lancing site. The rim presses against the dermal tissue to pucker tissue at the lancing site into the cavity and to constrict veinal capillaries adjacent the lancing site. The puckered tissue ensures that the lance is not pressed into bone structure, and the vasoconstriction causes a localized engorgement at the lancing site. The lancet further has a manually holdable casing that forms an aseptic enclosure for the lancing blade, with a septum that the blade pierces in snaping to the lancing position.

6 Claims, 7 Drawing Figures PATENTEflstrzslsn SHEET 1 0F 2 FIG. 3

FIG.2

'IIIIIII PAIEm nsirzslsra VIIIIIIII SURGICAL LANCET HAVING CASING BACKGROUND 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.

The invention provides improvements for the lancet described in the commonly-assigned and copending US. Pat. application Ser. No. 884,861 filed Dec. 15, 1969 in the name of Wesley G. Perry for Snap-Acting Surgical Lancet. As indicated in the record of that copending application, prior art regarding this invention is set forth in US. Pat. Nos. 6,288; 16,478, and 16,479.

An object of the invention is to provide a surgical lancet that does not require packaging to maintain the lancing blade aseptic prior to use.

Another object of the invention is to provide a surgical lancet having an innocuous appearance. In particular, it is an object to provide a small, compact surgical lancet in which the lancing blade and blade-driving mechanism are hidden from view.

A further object of the invention is to provide a surgical lancet that precludes the lancing blade from bruising the patients bone, even when the lancet is pressed firmly against a finger or other dermal tissue which overlies bone structure.

It is also an object of the invention to provide a surgical lancet construction that enhances the delivery of a significant volume of blood to a dermal puncture.

Another object of the invention is to provide a surgical lancet construction that securely holds the lancing blade in a cocked position, and yet is readily manipulated to release the blade for lancing.

A further object of this invention is to provide a low cost and readily assembled construction for a lancet of the above character. In particular, it is an object to provide a lancet of the above character of such low cost as to be economically disposable.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

SUMMARY OF THE INVENTION A surgical lancet according to the invention has a casing by which the lancet is manually held and operated and, further, which provides an aseptic enclosure for the lancing blade. The lancet accordingly does not require separate aseptic packaging. The casing includes a septum that the lancing blade pierces upon being released to form the desired dermal puncture. Further, the casing carries the blade-releasing actuator by means ofa web that allows ready operation of the actuator while maintaining the aseptic enclosure intact.

The lancet further has a presser foot or pad that puckers dermal tissue, and that develops a localized congestion of blood, at the lancing site. These features ensure that the lancing operation does not bruise the patients bone structure because of undue pressing of the lancet against a patients skin. Also, the localized engorgement enhances the collection of a significant volume of blood from the dermal puncture.

The invention provides these features with a recess or cavity in the presser foot surface directly above the lancing site, and with a cavity-encircling rim or shoulder. When the lancet is pressed against the tissue to be punctured, the rim constricts veinal capillaries around the lancing site, but the more rigid arterial vessels resist constriction. Accordingly, blood congests in the tissue at the lancing site, thereby enhancing the volume of blood that is available at the puncture. Further, the pressing of this presser foot against the tissue at the lancing site tends to pucker the tissue into the cavity, and the amount of puckering tends to increase with the force with which the lancet is pressed against the tissue.

The invention provides the foregoing features with a lancet construction that is of such low cost that it is economical to use the lancet only once and then discard it.

The invention accordingly comprises the features of construction, combinations of elements and arrangements 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, taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspectiveview, partially broken away, of a surgical lancet embodying the invention;

FIG. 2 is a sectional view, partially broken away, of the lancet of FIG. 1 in the cocked position;

FIG. 3 is an enlarged fragmentary view, similar to FIG. 2, of the lancet of FIG. 1 showing the lancet actuator partially depressed to release the lancing blade;

FIG. 4 is an elevation view similar to FIG. 2 and showing the lancet of FIG. 1 in the lancing position;

FIG. 5 is an exploded view of the lancet of FIG. 1;

FIG. 6 is a perspective view, partially broken away, of a modified lancet construction in accordance with the invention; and

FIG. 6A is a fragmentary enlarged sectional view of i the construction in FIG. 6, when closed, with the section being taken throughsocket element 94 of FIG. 6.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS FIGS. 1 and 5 show alancet 10 having an. innerhousing 12 that mounts a blade-carryingarm 14. Thehousing 12 restrains the blade in a cocked position, shown in solid lines, until the arm is released to snap to a lancing position, shown in dashed lines. Thehousing 12 seats within acasing cover 16, and acasing bottom 18 sealingly fits onto the cover to enclose thehousing 12 andarm 14 fully. With further reference to FIGS. 1 and 5, thearm 14 has a mounting section 14a, a blade-drivingspring section 14b, and alatch section 14c. Further, the arm carries alancing blade 20, formed integral with the arm in the illustrated embodiment. As further illustrated. the arm is preferably made from a single strip of material, such as metal, which provides the strong bladedriving spring force and provides the requisite blade sharpness.

More specifically, a portion of the arm-forming strip is bent upward at essentially a right angle to form the upstanding mounting section and the other, forward end of the strip is angled upward relative to the intermediate spring section to form thelatch section 14c. Thus, a side elevation view of the arm when in the lancing position has roughly a U-shape, with the tom of the U7 The latch section of thearm 14 further is fabricated to form twoprongs 22 and 24, each of which has an outwardlyflaring barb 26, 28 at the extreme end.

Theblade 20 protrudes orthogonally from thearm spring section 14b, in the direction opposite to the direction in which the illustrated mounting section 14a andlatch section 14c extend. As shown in FIG. 1, the illustratedblade 20 has two side edges, a forward side edge 20b and a rear side edge 200, that extend transversely from the arm spring section adjacent the juncture of that section with thelatch section 14c. The two side edges diverge from each other with increasing distance from the arm spring section, and the forward edge 20b is significantly longer than therear edge 20c. The illustratedcutting edge 20a is straight and, by virtue of the flaring geometry of the side edges, engages each forward edge with an acute angle. With this geometrical arrangement, only theblade edge 20a cuts tissue being lanced; hence, for cost savings, it is the only blade edge which needs to be sharpened.

Theinner housing 12 serves to mount thebladecarrying arm 14, and to hold it in the cocked position until released. The arm and housing are assembled first in the fabrication of thelancet 10, after which the arm is cocked. The sub-assembly of these twoelements 12 and 14 is then readily assembled with casing-formingcover 16 and bottom 18. The illustrated housing has a box-like section formed by fourperipheral walls 30, 32, 34 and 36, has an open bottom, and has a truncated, pyramid-like superstructure adjacent the forward end to provide two upwardly-facing barb-engaging latching surfaces 38 and 40. The convergingwalls 37, 39 that form those latching surfaces form barb-deflecting cams. The illustratedhousing 12 further has atop panel 42 spanning the peripheral walls about the superstructure.

The housing backwall 36 hasslots 44, 44 extending upward therein for seatedly receiving the tab-like mounting section 140 of the blade-carryingarm 14. After assembly of the blade-carryingarm 14 with theinnerhousing 12 in this manner, the arm is cocked by bending it from the normal dashed-line position 14 (FIG. to the cocked position shown with solid lines. This bending of the arm moves the pronged,forward latch section 14c upward between theinwardlywedging camming walls 37 and 39. The resultant camming action squeezes theprongs 22 and 24 together until the arm is fully cocked, at which point thebarbs 26 and 28 protrude outward from theinnerhousing 12 above the latching surfaces 38 and 40, which the barbs engage to hold the arm in the cocked position.

Thecasing cover 16 has four peripheral walls: afront wall 46, aback wall 48, and twoside walls 50 and 52, that form a socket-like receptacle into which thehousing 12 slidably seats, with the latch elements of the housing andarm 14 adjacent thefront wall 46. A downwardly facing shelf orshoulder 54 on the inner surfaces of the walls 46-52 fixes the position of thehousing 12 within thecasing cover 16.

Atop panel 56 of the cover has athin web 58, like an annular diaphragm, that mounts arelease actuator 60 to the top panel. Therelease actuator 60 is an essentially rigid button having two outwardly-flairing, barbcompressing earns 61 and 63 extending into the cover interior from the inner surface of thetop panel 56. The actuator is adjacent the forward end of the lancet with the cams above thebars 26 and 28 of thebladecarrying arm 14 when in the cooked position, as shown in FIG. 1.

The casing bottom 18 has abottom panel 62 from which four walls: afront wall 64, aback wall 66 and twoside walls 68 and 70 protrude upwardly. These walls are spaced inwardly from the edges of thepanel 62 to form a bottom panel lip that matingly seats against the bottom edges of the casing cover walls 46-52 in the assembled lancet. Abarbed sealing rib 72 is preferably provided encircling the walls 64-70 for seating in a mating recess in the cover walls 4652. The casing bottom walls 64-70 telescopingly fit within the cover walls 46-52 with a secure aseptic seal therebetween enhanced by therib 72. Thus, the casing bottom snaps onto the casing cover to form an aseptic enclosure for thehousing 12 and blade-carryingarm 14, and with the upper edges of the bottom walls 64-70 securing thehousing 12 in place.

Theback wall 66 of the casing bottom 18 abuts under the back end of the blade-carryingarm 14, and inner portions of thehousing wall 36 abut the arm directly thereabove, to minimize bending at this juncture of thearm sections 14a and 14b in addition to securing the arm mounting section in thehousing 12.

As further shown in FIGS. 1 and 2, adjacent the front end, the casing bottom 18 has apresser foot portion 74. This portion, which is placed over dermal tissue at the site to be punctured, has a recess orcavity 76 in the lower surface of the casing bottom, formed by reducing the thickness of thebottom panel 62. The remaining thin wall of the bottom panel within thepresser foot portion 74 forms aseptum 78, which the lancing blade pierces and through which it produces when in the lancing position, FIG. 4. The full thickness of the bottom panel around the edges of theseptum 78 encircling thechamber 76 forms avasoconstricting rim 80.

Thelancet 10 is used as follows. Thecasing cover 16 provides a manually holdable body element for the casing, the operator grasps theopposed side walls 50 and 52 between thumb and forefinger, with the index finger ready to depress theactuator 60. With the lancet thusly held, thepresser foot portion 74 is placed against the dermal tissue, typically a fingertip as indicated in FIG. 4, to be punctured. As the operator presses the presser foot portion firmly against the fingertip, thebottom panel 62, and particularly therim 80 thereon encircling theseptum 78, vasoconstricts veinal vessels in the patients dermal tissue, but the arterial vessels, being inherently more rigid, do not collapse under this pressure. The vasoconstriction causes a localized engorgement in the dermal tissue of the patient at the lancing site bounded by therim 80. This localized conjustion of blood at the lancing site enhances the volume of blood that will be available for collection from the laneing site when it is punctured with the lancing blade.

Further, the recessed bottom panel surface. which forms thecavity 76, allows the dermal tissue to pucker up into the void space. This puckering of the dermal tissue maintains the inner surface of the lancet bottom panel spaced a sufficient distance from whatever bone structure lies under the dermal tissue, so that even when the lancet is pressed against this tissue with unusual force, the puckered tissue spaces the lancet from any bone structure which may be present, thereby significantly diminishing the likelihood that the lancing blade will injure the bone structure.

With the lancet held over the lancing site in the foregoing manner, the operator simply depresses therelease actuator 60, typically with the index finger. FIG. 2 shows the position of the release actuator when the lancet is cocked. As the operator depresses theactuator 60, the barb-compressing earns 61, 63 increasingly engage thebarbs 26, 28 and resiliently deflect theprongs 22, 24 together, as indicated in FIG. 3. This releasing action quickly disengages thebarbs 26, 28 from thehousing 12 latching surfaces 38, 40, which releases thearm 14 to snap from the cocked position to the lancing position. As the arm snaps into the lancing position, theblade 20 pierces theseptum 78, as shown in FIG. 4, at the center of the presser foot portion and protrudes therebeyond to effect the desired dermal puncture.

Thelancet bottom panel 62 interferingly engages with the blade-carryingarm 14 to limit the movement of the arm into the lancing position. This blocking action by thebottom panel 62 in engaging the bladecarrying arm, together with the length of theblade 20, provide secure control of the depth of the puncture which the lancet provides.

The lancet housing, and casing cover and easing bottom shown in FIGS. 1-5 can bemolded of synthetic resin, such as a thermoplastic material. In one instance, a lancet as shown has thehousing 12,casing cover 16 and casing bottom 18 each molded of polyethylene. Further by way of example, this lancet has aseptum 78 with a minimum thickness of 0.002 inch and aweb 58, on thecasing cover 16, approximately 0.01 inch thick. Other constructions than the illustrated one detailed hereinabove can of course be used to fabricate lancets in accordance with the invention. As an elementary example, alternative to having aseparate casing cover 16 andinnerhousing 12, thehousing 12 can be eliminated and the casing cover provided with structure like thehousing slot 44 for mounting the blade-carryingarm 14. Further, the casing cover of this modified construction can also include the camming and latching elements which the illustratedhousing 12 provides, by molding or otherwise forming them directly on the inside of thecasing cover walls 50 and 52.

FIG. 6 shows still another way of fabricating a lancet in accordance with the invention. The FIG. 6lancet 84 has only two parts, a clam-shell type casing 86 and aspring arm 88 that carries the lancing blade and hence is similar to the blade-carryingarm 14 and blade described with reference to FIGS. l-5. Thecasing 86 has twomating parts 86a and 86b integrally joined by acontinuous hinge 86c. The casing parts are formed withmating edges 90a and 90b that form, when the two parts are folded together and mated, an overlapping or other aseptic seal, as shown in the detail view of FIG. 6A. The twocasing parts 86a and 86b preferably also have interengaging latching connector elements. One such latching connector shown has amale element 92 mountingly carried on the inner side wall of thecasing part 86a, and has a latchingsocket element 94 mountingly carried on the inner side wall of thecasing part 86b and positioned to telescopingly receive and hold themale element 92, as in FIG. 6A.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained. 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.

Having described the invention, what is claimed as new and secured by Letters Patent is:

l. A surgical lancet having i. a manually holdable first member,

ii. a presser foot disposed on said first member for placing against dermal tissue to be lanced,

iii. a lancing blade pointed in a first direction, and

iv. means mounting said blade to said first member for movement relative to said first member between a lancing position where said blade protrudes in said first direction beyond said presser foot, and a retracted position where said blade is removed from said presser foot in a second direction opposite to said first direction, and

having the improvement wherein said presser foot A. has vasoconstricting rim means at least partially encircling a first area through which said blade protrudes when in said lancing position and adapted to constrict along the periphery of said area veinal capillaries of the dermal tissue to be lanced by said blade, and

B. forms cavity means within said rim means and recessed from said rim means in said second direction for a depth sufficient to receive, without significant constriction of veinal capillaries therein, dermal tissue bounded by said rim means.

2. A lancet according to claim 1 having the further improvement in that said presser foot has an initially unbroken septum forming at least part of a wall bounding said cavity means, and through which said blade protrudes when in said lancing position.

3. A lancet according to claim 1 having the further improvement in that said rim means of said presser foot is contoured to seat on a human finger.

4. A surgical lancet having i. a manually holdable first member,

ii. a presser foot disposed on said first member for placing against dermal tissue to be lanced,

iii. a lancing blade pointed in a first direction, and

iv. means mounting said blade to said first member for movement relative thereto between a lancing position where said blade protrudes in said first direction beyond said presser foot, and a retracted position where said blade is removed from said presser foot in a second direction opposite to said first direction, and

having the improvement comprising a body casing totally enclosing said mounting means and blade and forming an aseptic enclosure therefor, said casing forming said first member and said presser foot, and having a normally intact septum forming part of said enclosure and pierced by said blade in the movement thereof from said retracted position to said lancing position.

5. A lancet according to claim 4 having the further improvement wherein A. said mounting means includes an elongated spring member having a mounting section at a first end,

a latch section at another end and a blade-driving position, and spring section therebetween which carries said 3. carrying a release actuator movable to disengage blade, said spring member resiliently urging said said latch section from said latching means for blade thereon to move with a snap-action from said allowing said blade to snap into said lancing posiretracted position to said lancing position, and tion.

B. two matingly engaging casing elements form said 6. A lancet according to claim 5 wherein said casing aseptically-enclosing casing, said casing elements elements further form flexible web means forming part 1. forming said septum, of said casing enclosure and mounting said release ac- 2. carrying latching means engageable with said tuator for said disengaging movement.

latch section to hold said blade in said retracted 10

Claims (8)

1. A surgical lancet having i. a manually holdable first member, ii. a presser foot disposed on said first member for placing against dermal tissue to be lanced, iii. a lancing blade pointed in a first direction, and iv. means mounting said blade to said first member for movement relative to said first member between a lancing position where said blade protrudes in said first direction beyond said presser foot, and a retracted position where said blade is removed from said presser foot in a second direction opposite to said first direction, and having the improvement wherein said presser foot A. has vasoconstricting rim means at least partially encircling a first area through which said blade protrudes when in said lancing position and adapted to constrIct along the periphery of said area veinal capillaries of the dermal tissue to be lanced by said blade, and B. forms cavity means within said rim means and recessed from said rim means in said second direction for a depth sufficient to receive, without significant constriction of veinal capillaries therein, dermal tissue bounded by said rim means.

2. A lancet according to claim 1 having the further improvement in that said presser foot has an initially unbroken septum forming at least part of a wall bounding said cavity means, and through which said blade protrudes when in said lancing position.

2. carrying latching means engageable with said latch section to hold said blade in said retracted position, and

3. carrying a release actuator movable to disengage said latch section from said latching means for allowing said blade to snap into said lancing position.

3. A lancet according to claim 1 having the further improvement in that said rim means of said presser foot is contoured to seat on a human finger.

4. A surgical lancet having i. a manually holdable first member, ii. a presser foot disposed on said first member for placing against dermal tissue to be lanced, iii. a lancing blade pointed in a first direction, and iv. means mounting said blade to said first member for movement relative thereto between a lancing position where said blade protrudes in said first direction beyond said presser foot, and a retracted position where said blade is removed from said presser foot in a second direction opposite to said first direction, and having the improvement comprising a body casing totally enclosing said mounting means and blade and forming an aseptic enclosure therefor, said casing forming said first member and said presser foot, and having a normally intact septum forming part of said enclosure and pierced by said blade in the movement thereof from said retracted position to said lancing position.

5. A lancet according to claim 4 having the further improvement wherein A. said mounting means includes an elongated spring member having a mounting section at a first end, a latch section at another end and a blade-driving spring section therebetween which carries said blade, said spring member resiliently urging said blade thereon to move with a snap-action from said retracted position to said lancing position, and B. two matingly engaging casing elements form said aseptically-enclosing casing, said casing elements

6. A lancet according to claim 5 wherein said casing elements further form flexible web means forming part of said casing enclosure and mounting said release actuator for said disengaging movement.

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