Surgical Lancet Having Casing

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

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 U.S. 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 U.S. 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 patient's 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 of a 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 patient's bone structure because of undue pressing of the lancet against a patient's 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 perspective view, 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 the construction in FIG. 6, when closed, with the section being taken through socket element 94 of FIG. 6.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS

FIGS. 1 and 5 show a lancet 10 having an inner-housing 12 that mounts a blade-carrying arm 14. The housing 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. The housing 12 seats within a casing cover 16, and a casing bottom 18 sealingly fits onto the cover to enclose the housing 12 and arm 14 fully.

With further reference to FIGS. 1 and 5, the arm 14 has a mounting section 14a, a blade-driving spring section 14b, and a latch section 14c. Further, the arm carries a lancing 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 blade-driving 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 14a and the other, forward end of the strip is angled upward relative to the intermediate spring section to form the latch section 14c. Thus, a side elevation view of the arm when in the lancing position has roughly a U-shape, with the mounting section 14a and the latch section 14c forming the legs of the U and the spring section forming the bottom of the U. The latch section of the arm 14 further is fabricated to form two prongs 22 and 24, each of which has an outwardly flaring barb 26, 28 at the extreme end.

The blade 20 protrudes orthogonally from the arm spring section 14b, in the direction opposite to the direction in which the illustrated mounting section 14a and latch section 14c extend. As shown in FIG. 1, the illustrated blade 20 has two side edges, a forward side edge 20b and a rear side edge 20c, that extend transversely from the arm spring section adjacent the juncture of that section with the latch 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 the rear edge 20c. The illustrated cutting 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 the blade edge 20a cuts tissue being lanced; hence, for cost savings, it is the only blade edge which needs to be sharpened.

The inner housing 12 serves to mount the blade-carrying arm 14, and to hold it in the cocked position until released. The arm and housing are assembled first in the fabrication of the lancet 10, after which the arm is cocked. The sub-assembly of these two elements 12 and 14 is then readily assembled with casing-forming cover 16 and bottom 18. The illustrated housing has a box-like section formed by four peripheral 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 converging walls 37, 39 that form those latching surfaces form barb-deflecting cams. The illustrated housing 12 further has a top panel 42 spanning the peripheral walls about the superstructure.

The housing back wall 36 has slots 44, 44 extending upward therein for seatedly receiving the tab-like mounting section 14a of the blade-carrying arm 14. After assembly of the blade-carrying arm 14 with the innerhousing 12 in this manner, the arm is cocked by bending it from the normal dashed-line position 14' (FIG. 5) to the cocked position shown with solid lines. This bending of the arm moves the pronged, forward latch section 14c upward between the inwardly-wedging camming walls 37 and 39. The resultant camming action squeezes the prongs 22 and 24 together until the arm is fully cocked, at which point the barbs 26 and 28 protrude outward from the innerhousing 12 above the latching surfaces 38 and 40, which the barbs engage to hold the arm in the cocked position.

The casing cover 16 has four peripheral walls: a front wall 46, a back wall 48, and two side walls 50 and 52, that form a socket-like receptacle into which the housing 12 slidably seats, with the latch elements of the housing and arm 14 adjacent the front wall 46. A downwardly facing shelf or shoulder 54 on the inner surfaces of the walls 46-52 fixes the position of the housing 12 within the casing cover 16.

A top panel 56 of the cover has a thin web 58, like an annular diaphragm, that mounts a release actuator 60 to the top panel. The release actuator 60 is an essentially rigid button having two outwardly-flairing, barb-compressing cams 61 and 63 extending into the cover interior from the inner surface of the top panel 56. The actuator is adjacent the forward end of the lancet with the cams above the bars 26 and 28 of the blade-carrying arm 14 when in the cocked position, as shown in FIG. 1.

The casing bottom 18 has a bottom panel 62 from which four walls: a front wall 64, a back wall 66 and two side walls 68 and 70 protrude upwardly. These walls are spaced inwardly from the edges of the panel 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. A barbed sealing rib 72 is preferably provided encircling the walls 64-70 for seating in a mating recess in the cover walls 46-52. The casing bottom walls 64-70 telescopingly fit within the cover walls 46-52 with a secure aseptic seal therebetween enhanced by the rib 72. Thus, the casing bottom snaps onto the casing cover to form an aseptic enclosure for the housing 12 and blade-carrying arm 14, and with the upper edges of the bottom walls 64-70 securing the housing 12 in place.

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

As further shown in FIGS. 1 and 2, adjacent the front end, the casing bottom 18 has a presser foot portion 74. This portion, which is placed over dermal tissue at the site to be punctured, has a recess or cavity 76 in the lower surface of the casing bottom, formed by reducing the thickness of the bottom panel 62. The remaining thin wall of the bottom panel within the presser foot portion 74 forms a septum 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 the septum 78 encircling the chamber 76 forms a vasoconstricting rim 80.

The lancet 10 is used as follows. The casing cover 16 provides a manually holdable body element for the casing, the operator grasps the opposed side walls 50 and 52 between thumb and forefinger, with the index finger ready to depress the actuator 60. With the lancet thusly held, the presser 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, the bottom panel 62, and particularly the rim 80 thereon encircling the septum 78, vasoconstricts veinal vessels in the patient's 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 the rim 80. This localized conjustion of blood at the lancing site enhances the volume of blood that will be available for collection from the lancing site when it is punctured with the lancing blade.

Further, the recessed bottom panel surface, which forms the cavity 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 the release 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 the actuator 60, the barb-compressing cams 61, 63 increasingly engage the barbs 26, 28 and resiliently deflect the prongs 22, 24 together, as indicated in FIG. 3. This releasing action quickly disengages the barbs 26, 28 from the housing 12 latching surfaces 38, 40, which releases the arm 14 to snap from the cocked position to the lancing position. As the arm snaps into the lancing position, the blade 20 pierces the septum 78, as shown in FIG. 4, at the center of the presser foot portion and protrudes therebeyond to effect the desired dermal puncture.

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

The lancet housing, and casing cover and casing bottom shown in FIGS. 1-5 can be molded of synthetic resin, such as a thermoplastic material. In one instance, a lancet as shown has the housing 12, casing cover 16 and casing bottom 18 each molded of polyethylene. Further by way of example, this lancet has a septum 78 with a minimum thickness of 0.002 inch and a web 58, on the casing 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 a separate casing cover 16 and innerhousing 12, the housing 12 can be eliminated and the casing cover provided with structure like the housing slot 44 for mounting the blade-carrying arm 14. Further, the casing cover of this modified construction can also include the camming and latching elements which the illustrated housing 12 provides, by molding or otherwise forming them directly on the inside of the casing cover walls 50 and 52.

FIG. 6 shows still another way of fabricating a lancet in accordance with the invention. The FIG. 6 lancet 84 has only two parts, a clam-shell type casing 86 and a spring arm 88 that carries the lancing blade and hence is similar to the blade-carrying arm 14 and blade 20 described with reference to FIGS. 1-5. The casing 86 has two mating parts 86a and 86b integrally joined by a continuous hinge 86c. The casing parts are formed with mating 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 two casing parts 86a and 86b preferably also have interengaging latching connector elements. One such latching connector shown has a male element 92 mountingly carried on the inner side wall of the casing part 86a, and has a latching socket element 94 mountingly carried on the inner side wall of the casing part 86b and positioned to telescopingly receive and hold the male 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.

Claims

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

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.

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

1. forming said septum,

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.

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.