US2409979A - Hypodermic needle - Google Patents

Description

Oct. 2z, 1946. 'R HUBER 2,409,979

HYPODERMIC NEEDLE Filed March 14, 1946 INVENTOR ATTORNEYS Patented Get. .22, 1946 UNITED STATES PATENT OFFICE HYPODERMIC NEEDLE Ralph L. Huber, Seattle, Wash. Application March 14, 194.6, Serial No. 654,373

4 Claims.V (Cl. 12S-221) This invention relates to a structurally and functionally improved hypodermic needle. The present application is a continuation in part of my copending application Serial No. 478,737, filed March 11, 1943, for a Hypodermic needle.

It is an object of the invention to provide a hypodermic needle 'embodying a construction such that only minor pain Will be experienced by the patient as the needle penetrates the tissue. Moreover, a needle embodying the present teach ings may be thrust into position with minimum effort and also be readily withdrawn from that position.

An additional object of the invention is that of providing a hypodermic needle in which plug cutting, with resultant danger of embolism will, in effect, be eliminated.

Still another object vis that of designing a device of this type through which medicament may be readily injected into the tissues or veins of a patient with no danger of back-pressures being generated. Accordingly, it will be feasible to employ needles, the bodies of which will have minimum diameters Without reducing the volume or speed of the `injection of medicament or Withdrawal of blood.

Still another object is that of furnishing a hypodermie needle which will be of simple-and rugged design and which may be manufactured by quantity production methods at minimum expense.

With these and other objects in mind, reference is had to the attached sheet of drawing illustrating practical embodiments of the invention, and in which:

Fig. 1 is a fragmentary view of the outer end of a hypodermic needle;

Fig. 2 is a transverse sectional view, taken along the lines 2-2 and in the direction of the arrows as indicated in Fig. 1;

Fig. 3 is a side view of a needle end and showing an alternative form of construction; Y

Fig. 4 is a transverse sectional view taken along the lines 4 4 and in the direction of the arrows as indicated in Fig. 3; and

Fig. 5 isa face view of the parts as shown Vin Fig. 3.

In these views, the reference numera1 I0 indicates a cannula formed with a bore I I. As shown in Figs. 1 and 2, the outer end of this bore termi- 5o nates in an opening or space defined by edges I2. The area of this space is in excess of the crosssectional area of the bore II. Therefore, no back-pressures, such as Would require the use of a large diameter needle, Will be created when ends of the edges fluid is flowing from the bore and being ejected through the space or opening.

The edges I2 extend substantially parallel to the axis of the body I6 and in line with an edge portion of said body. This has been shown especially in Fig. 2. These edgesprovided by the Walls of the tube I-fdiverge from the outer part of the end portion of the needle to a Zone where they are separated toa maximum extent. Beyond this zone, they converge and merge into each other, as shown in Fig. 1. The Wall of the tubular body IU, Within the outer end portion of the needle, is of diminishing area and transversely curved. Where it joins with the outer edge portions I2, a tissue-piercing point I3 is provided.

The converging edges extend at acute angles with respect to each other and also with respect to the converging adjacent curved surface of the wall in the outer portion. The zones of juncture of the edges I2 and the rear Wall portion define opposed cutting surfaces. Due to the fact that the degree of longitudinal curvature of the outer end Wall portion is gradual such that it merges into the continuing surface defined by the eX- terior face of the tube body l, a cam surface is furnished which will function as a retractor. In other words, after the point has pierced the skin of the patient, the cutting edges Will enlarge this perforation in the form of a slit. Thereuponand during continued projection of the `needlethe curved surface of the outer portion will act to bulge or retract one side edge of the slit so that the aperture Willbe enlarged to accommodate the shank of the needle.

In the form of construction shown in. Figs. 3 to 5 inclusive, it will be observed that there is again` involved a body Iii which is preferably circular in cross-section and which has a tubular bore i I, terminating in a discharge end or outlet defined by the edges of the wall of the body as shown in Fig. 5. The body is bent through the zone indicated at I4, to provide a curved surface of dirninishing` area I5, extending in the direction of the vouter parts of the end portion `of the needle. This curved surface is interrupted by the edges I1 which, at their points of merger `with the curved surface, provide cutting edges.

In order that such cutting edges may embody maximum effectiveness, a grinding or sharpening operation is resorted to. This operation may occur in any proper surface to effect the desired results. However, it is preferably resorted to throughout the Zonerof divergence of the outer I'I. This Will result in beveled surfaces I8 which extend at proper angles with respect to the curved surface I5 so that sharp cutting edges are provided. Accordingly, a slitting function is achieved as the needle is caused to pierce the tissue. At the point of juncture of the surfaces I8 and I5, a tissue-piercing point is defined.

As will be understood from a consideration of the foregoing structures, a cannula is furnished in which a very fine piercing point is embodied, the' surfaces I2 or-I of which extend at an acute angle with respect to each other as well as with respect to the curved surface embodied in the outer end portion of the needle. Therefore, not alone will minimum pain result to the patient as the point of the needle pierces or initially perforates the tissue but also, pain will be held to a,

minimum incident to the fact that no tearing of the tissues occurs as the needle is continuously projected. More especially, as a consequence of the oppositely extending cutting surfaces or edges, substantially nothing more than a slit will be provided as the perforation is enlarged. Incident to the provision of the gently tapered surface I5, one edge of this slit is retracted or bulged Vunder continued projection of the needle. This results in an enlargement of the tissue opening to provide an aperture which will continue to expand as the needle isprojected, until the tissue rides over the curved surface I4 which defines the point or zone of merger between the outer end portion of the needle and its Vmain body I0. As shown, this zone is preferably inwardly of the inner end of the edges I2 or Il. Due to the fact that no heel portion is present, a patient will suffer no substantial pain in having the zone of merger between the needle end portion and the needle shank pass into the tissues. This will provide for the final enlargement of the tissue perforation or aperture to a diameter corresponding to that of thebody I.

As a consequence of the outlet end of the bore and cutting edges being disposed in a plane parallel to the direction of thrust, no plug cutting will result from the edges of the outlet moving laterally in contact with the skin. Also, due to the fact that a substantially flat face defines this outlet end and this face is disposed substantially in line'with the side edge of the needle shank, the inner end of the outlet will not'act as a cutting surface to shave off portions of tissue as it passes through the skin. Thus, pain in this connection will be eliminated aside from the'fact that any danger of severed tissue being injected into a vein, or otherwise, will be avoided. Moreover, due to the fact that only a straight and clean slit remains after the needle is withdrawn, healing is promoted and no permanent scars result. v

As will be understood,'a needle constructed in accordance with the present teachings might be formed in a number of'diferent manners. However, any method which is presently visualized, involves the employment of a single cannula in which both the body and end portion of the needle are integral with each other. To provide this end portion, the cannula is cut along a line extending, for example, at an angle of from `iifteen to thirty degrees to its axis. Bending is resorted to preferably after the cut has been achieved. In said event, the end portion is bent to extend in a manner such that the cut face is parallel to the axis of the needle and substantially in line with one straight outer edge of the body I0. In such bending, care is employed to be sure that the curved surface of the outer endV portion merges into the surface of the tube in a gradual manner so that no heel" results.

The sharpening of the oppositely extending cutting edges is preferably achieved before the bending operation in both of the illustrated forms. This sharpening in its initial stages may occur by a grinding operation. Such operation may also serve to in effect cut off or remove the outer end portion of the needle and to form the desired flat face in the outer end portion. This grinding and cutting operation may be followed by Va finishing phase, at which time the beveled surfaces may be produced. Such sharpening results not alone in satisfactory edges defined by sections of the tube walls at their zone of juncture with the curved ,Wall but. also in the creation of a finely pointed,

tissue-piercing end portion. Due to the fact that the opening defined by the edges I2 or I'I is ofgreater area than the cross-sectional area of the bore II, no back-pressures will result and a needle of minimum diameter will therefore be employed, either to express medicament into tissue or to withdraw body fluid from a vein or otherwise. Due to the fact that it is unnecessary to employ an oversize cannula in any particular instance, pain is again reduced to a minimum in the use of a needle constructed in accordance with the present teachings. Also, it is obvious that no seepage of body fluids will occur to any appreciable extent along the outer face of the needle shank because of the elasticity of the tissues and the fact that the aperture in the flesh will be substantially equal in area to the area of that shank. Also, when the needle is withdrawn, a clean slit remains, the edges of which will quickly grow together in a manner such that no visible scar results.

l'romV the foregoing it will be appreciated that, among others, the several objects of the invention as 'specically aforenoted are achieved. Obvi ously, numerous changes in construction and rearrangement of the parts might be resorted to without departing from the spirit of the invention as dened by the claims.

I claim: Y

1. A hypodermic needle comprising a tubular body having an end portion comprising a surface in which an aperture defining the end of the tubel bore is formed, said surface being substantially flat, with the inner edge thereof eX- tending in a plane substantially tangential to the curved outer surface of the tube, in substantial alignment with the straight longitudinal edge of the tube and in substantial parallelism with the longitudinal axis of the same and with no portion of the surface projecting substantially beyond said plane, a tissue-piercing point at the outer end of said surface, a transversely curved wall also forming a part of ,said end portion, said end wall being of diminishing area in the direction of said point and in the opposite direction mergingfree from any heel-into the curved outer tube surface, said wall extending from one to the other side edge of said'ilat surface, V4 the face of said flat surface adjacent its edges being beveled from said piercing 'point t'o the zoneiof maximum tube diameter, to provide cutting edges diverging from said piercing point whereby, upon bringing said piercing point intoI contact with tissue and thereupon exerting a continuing axial thrust in the direction of said point, a piercing of the tissue will initially occur, a cutting of theV tissue by such edges solely in lateral and outward directions to define a substantially straight slit will thereupon follow, and simultaneously with,A the formation of such slit the tissue contacted bythe curved outer wallrwill be retracted to dilate the orice formed by said piercing point to an area not substantially in excess of that of said tubular body.

2. A hypodermic needle comprising a straight tubular shank and an entry end formed at the outer end of said shank vsaid entry end including a bent portion of the needle and a ground surface which is substantially oval shaped, the inner edge of said surface being disposed in a plane that is substantially tangential with a longitudinal edge of said tubular shank and extending from said tubular shank in substantial alignment with said longitudinal edge of such shank and in substantial parallelism with the longitudinal axis of said shank and with no portion of the surface projecting substantially beyond said plane, the inner edge of said surface defining an outlet opening at one side of the needle and the outer edge of said surface at its inner end merging into the said longitudinal edge of said tubular shank so that such surface at its inner end forms an extension of such straight longitudinal edge to the inner edge of such surface, the outer edge of said surface at its outer end being sharpened to provide a piercing point and an incisive edge at the outer terminalend of the needle and the exterior surface of the portion of the needle forming said entry end being rounded and inclining toward and forming a juncture with said incisive edge.

3. A hypodermic needle substantially straight throughout its entire length and adapted to be inserted into the flesh of a patient by a straight thrust in the direction of its longitudinal axis, said needle comprising a straight tubular shank having a circular cross section and an entry end formed at the outer end of said shank, said entry end including a bent portion and a ground surface having its inner edge disposed in a plane that is substantially tangential with a longitudinal edge of said straight tubular shank, said ground surface being substantially oval shaped and extending from the outer end of said tubular shank so as to be substantially contained inside said tangential plane, the inner edge of said surface defining an unrestricted outlet opening to one side of the needle and the outer edge of such surface merging at its inner end into said longitudinal edge of the shank so that such surface at its inner end forms an extension of such straight longitudinal edge to the inner edge of such surface, the outer edge of such surface at its outer end being sharpened, to provide a piercing point and an incisive edge at the terminal end of the needle and extending from side to side of the needle and transversely to such longitudinal edge of the shank and the exterior surface of the needle tube forming said entry end being rounded and inclining lengthwise of the needle towards said incisive edge and forming a juncture with the latter.

4. A hypodermic needle adapted to be inserted into the flesh of a patient by a straight thrust in the direction of its longitudinal axis and comprising a tube substantially straight throughout its length and having at its outer extremity an entry portion of gradually diminishing thickness in one direction, said entry portion being bounded longitudinally by a bent portion of said tube which inclines in a lengthwise direction at an angle to the longitudinal axis of such tube and by a substantially oval shaped ground surface, the inner edge of said surface being disposed in a plane that is substantially tangential with a straight longitudinal edgeof said tube so that it extends in substantial alignment with such straight longitudinal edge of said tube and in substantial parallelism with the longitudinal axis of said tube with no portion of said surface projecting substantially beyond said plane whereby the straight 'bore of said tube for the major portion of its length has a uniform circular cross section, while in the entry portion of such tube the cross-sectional configuration of the bore is the segment of a circle, the areas of such cross sectional segments gradually diminishing towards the outer end of said ground surface, the inner edge of said surface defining at one side of the tube an outlet opening of greater areav than the circular cross-sectional area of the tube and the outer edge of said surface, at its outer end, being sharpened to provide a piercing point and an incisive edge at the entry end of the tube.

RALPH L. HUBER.

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