US2217602A - Hypodermic needle - Google Patents

Description

Oct. 8, 1940. J. c. sMrrH HYPODERMIC NEEDLE Filed May 12, 1958 2 Sheets-Sheet l INVENTOR. Jesse Conrad/Snail@ Q Q o o Q Q QOOOQOOOOOOOOOQ w.@wwwwwwwwwwwwv ATTORNEYS Oct. 8, 1940. J. c. SMITH HYPoDERMIc NEEDLE 2 Sheets-Sheet 2 Filed May l2 1958 INVENTOR. @sse @bn/'ad /S'm Z SIBY r Ur/wv. ATTORNEYS. l

Patented Oct. 8, 1940 UNITED STATES PTENT oFFicE HYPODERMIO NEEDLE Jesse conrad smith, Merrick, N. y., assignmto MacGregor Instrument Company, Needham, Mass., a corporation of Massachusetts application May iz, 193s, sei-m No. 207,524 v claims. (ci. 12s-221) This invention relates to hypodermic needles and particularly to one of novel construction and increased eillciency and economy, this application being a re-ling in part of my previous ap- 5 plicatlon Serial No. 24,835, led June 4, 1935.

According to my inventions it can be produced at low manufacturing cost so as to be available to the professions and their service to the public without added charge and with greater safety in operative use.

The usual hypodermic needle, developed by long years of experience for use with syringes for giving various kinds of injections subcutaneously, had come to a rather standard type or types, generally accepted by doctors, dentists and `nurses for use on their patients. It generally consisted of a hub or base for engagement with the usual glass Luer syringe tip, and a so-called cannula which was really the needle portion of the instrument.

By highly developed processes these cannulae were eventually available as small seamless steel tubes of hollow wire-like formation. They were cut to length, tempered and carefully ground at one end to an angular incising point generally 'in a plane at an acute angle to the longitudinal axis of the hollow wire of the cannula stock.

The cannula of the hypodermic was usually set in a metal hub which was usually milled and turned out of contoured stock-and axially drilled and reamed for accurate'frlctionalv reception of the syringe tip. For the Luer type of syringe the hubs were formed with a conic recess to make careful frictional contact on the glass tip of the Luer or like syringe on which it was to be used as a combined instrument in the hand of the operator.

Unfortunately, in spite of high skill and the greatest of care, the cannulae of these hypo- 40 dermic needles would break while being thrust through the skin or underlying tissues of the patient. This was due to the fact that in most cases the steel needles or cannulae mounted in an independent hub tended to break at the joint line when the needle or cannula is set in the hub in a joint which formed a sharp fulcrum line. Such were often crystallized during soldering or by blows upon it when swaged in place.

Such breakages were nerve wracking to both operator and patient. Often the results were painful and so dangerous that various efforts were even made to provide needles that would break far enough back from the point to leave an external stub which couldbe located and surgically engaged for extraction.

Furthermore, needles which have rough surfaces or which carry particles or substances which adhere during the process of formation of the needles. and which are not removed, tend to carry infectious matter under the skin of the 5 patient, and such adhering particles or substances tend to come loose and be injected in the patients body tissues or circulatory system.

Moreover, irregularities in the interior surfaces or materials adhering to such surfaces, tend lo to obstruct the passage of injected fluid, and set up a point for rust formation or other co1'- rosive action which will weaken the needle, often to the point of breakage. `The removal of such irregularities or accumulated substancesl from the 15 outer surface may be readily accomplished but it is impossible as a practical matter to remove them from the inner surface after the fabrication of the needle is complete.

When an annealing process is utilized in the l0 formation of steel needles, scale, particularly in the form of oxides, tends to be formed and while such scale can be readily removed from the outer surface of the needle, that remaining in its bore is highly diilicult to eliminate. Needles produced 25 by Wide-drawing processes moreover, tend to gather particles of'carbon from the graphite lubricant employed, and to retain these particles. The usual steel needles tend to rust unless very carefullyhandled, and this tendency is often 3G accentuated by the sterilizing materials used.

It is of great importance that the bore of the needle be kept clear of the accumulation of any solids suspended in the injection fluid, and to this end it is desirable that a cleaning wire may 35 be readily inserted throughthe hub of the needle and passed along its length by continuous passage without encountering obstructions, and that the needle may be easily sterilized as to its interior. Accordingly my invention provides for 40 the avoidance of shoulders, pockets, or yother longitudinal obstructions Y which will tend to gather solid particles or oppose the movement of a cleaning wire or fluids.

Another important desideratum is the provision of a needle having a hub member which is sufliciently resilient frictionally to t over the nozzles of hypodermic syringes and the like even though the contours of these nozzles may vary slightly. 50

My concept, based on a careful study of the situation, was that of a hypodermic needle which would have no weakest place and so would stand up under adverse operative conditions and do so without embarrassing departure from acc vpteci 55 standards and the practice land habits formed thereon.

Needles according to my inventions have several advantages over those made with the old shaped hub with a swaged; soldered or brazed-in cannula. My needles, even under the strains imposedby the leverage of the syringe which the operator uses as a general handle, and evn with patients having tough resistant tissue to be penetrated, stand up in operative use because they transmit and absorb those stresses and strains which break the present type of hypodermic needle.

Aside from performance, the structures of my needles show consistently related factors which are self-explanatory to the professions and to those skilled in the manufacturing art.

For the purposes of ready comprehension of the novel construction of my needle and its advantages, it may be helpful at the outset to explain its novel basis of actual fabrication because of the long pre-conceived convictions of the trade to the contrary.

By reason of Patent Office classification the method and apparatus for making such needles is made the subject matter of a separate appli-- cation for patent, so that it is not claimed herein, but only suggested as explanatory of the accomplished fact which was supposed to be impossible.

Such a needle may be formed in one piece from a single blank of sheet metal. The provision for a one piece construction is highly advantageous. The metal used is desirably stainless steel, but in the broader aspects of the invention may be any metal or alloy which possesses, or which by treatment such as hardening and tempering, may be made to possess the desired hardness and other qualities, and which has enough ductility to permit it to be pressed and swaged in accordance with the invention. The term stainless steel is usedto define steel having a relatively high resistance to corrosion. A desirable stainless steel for use is, for example, commercial Carpenters No. 2, containing about 15% chromium and .3% carbon; alloys of berryllium with nickel (for example containing about 1.6% beryllium), alloys possessing properties which make them well adapted for use in accordance with the invention. Other beryllium alloys may be utilized. Nickel and various other hard metals and alloys which can be worked sufficiently for the purposes of the invention may be used. Cold rolled steel may be utilized where the needle is to be carefully protected or where for other reasons relative tendencies toward rusting are not an important draw back.

In accordance with my concept a. disc-like piece of sheet metal may be pressed into an elongated cup-like member. When the-cup-like member has been suiiiciently elongated and suitably shaped, as by die-pressing, the end which corresponds to the center of the die may, in carrying out theinvention, be elongated into needle form by a succession of swaging operations, each i' 'involving a series of intermittent pounding or squeezing actions which will be designated herein as blows, delivered at different points on the work schematically illustrated in an explanatory figure included in the drawings.

As illustrative of my inventions I have shown in the accompanying drawings novel needle types with indicated basis of fabrication. In these drawings:

Fig. 1 is a side elevation of a needle in accordance with my invention.

Fig. 2 is a central longitudinal section through the needle unit shown in Fig. 1.

Fig. 3 shows a modified form in elevation illustrating merging continuity of integral hub and cannula walls in my needle.

Fig. 4 shows a knurled cylindric form.

Fig. 5 indicates another type having more taper than that of Fig. 4, with a hub portion also cylindric and with parallel axial knurlings.

Fig. 6 is .an end view of the needle shown in Fig. 1 viewed from the open hub end.

Fig. 7 is a view partly sectioned indicative of the relation of one of my needles to a syringe tip on which lt is mounted and to an indicated area of application as of patient tissue.

Fig, 8 shows a section through its taper as at 8 8, Fig. 1. l

Fig. 9 is a similar section on the line 9 0, of Fig. 3, and

Fig. 10 shows an explanatory group of figures indicative of the progressive steps by which such a hypodermic structure may be developed to attain the continuous wall figure between integral hub and cannula according to-my concept of such a needle.

Embodiments of the invention are shown in the form of a hypodermic injection needle in Figs. 1, 2 and 3. As will be seen, the needle comprises a hub portion 9 and a cannula point portion l0 connected by a tapering portion I, which portions are formed of a single continuous wall of sheet metal. The needle so formed is without seams or breakage lines and has a thin practically uniform wall throughout its extent.

Such a needle exterior iiares in smooth longitudinal curves throughout the part where the hub portionv and the cannula portion merge so that there are no sharp fulcrum lines which would result in breakage. As will be apparent from consideration of Figs. 1 to 5, inclusive, the portion 8 connecting the hub 9 and cannula l0 is formed as a. concaved conic figure which merges with the straight cylindrical wall of the cannula I0 and preferably also with the h'ub 8,

.in a curve of a circle tangential to the walls of the cannula and hub. These will also be noted by comparisons of such sections as Figs. 8` and 9. The inner surface of the needle is likewise continuously smoothly curved longitudinally so as to be without shoulders or pockets which would interfere with easy washing or would obstruct the movement of a cleaning wire.

The point portion terminates in a sharp point II which may be of usual angular form ground and honed to incising sharpness. The inner surface of the hub has a slight taper to t about the nozzle`|2 of a hypodermic syringe I3 (Fig. 7). The bore of the point portion of the needle may be, say .005 in diameter, and the wall of this portion may be about .005" thick. 'I'he wall of the hub portion may have a thickness in the neighborhood of .020", if desired. Due to the uniform, thin contour of the upper portion of the hub, the hub has suincient elasticity to t snugly over a syringe nozzle having a periphery which does not exactly conform to the interior wall surface of its hub. Such needles are substantially free from breakage lines of any sort, and in accordance with my inventions the cannula portion can be semi-polished both inside and out and substantially free from surface irregularities and from adhering particles or substances which would roughen the surface or come loose in use.

For simple forms the needles are'preferably y finger hold in operation.

For the purposes of further visualizing the novel structure of my needles I have indicated in Fig. 10 certain significant steps in a method by which the invention may be commercially available and whereby a thin-walled tubular article like a needle may be produced. As exemplied such a method is adapted for the production vof needles such as are shown in Figs. l,l

2 and 3. Such a method involves turning up the edges of a disc-like piece of sheet metal to form a cup-like member. For example, a disc of stainless steel (or other suitable metal) as indicated at A, may be pressed into the blank indicated at B. For example, aldisc about the diameter of a quarter of a dollar, and about .017" in thickness may be utilized for the production of a hypodermic injection needle of usual commercial sizes. If desired, a disc-like piece may in a single operation be cut from a large sheet of metal and shaped to assume the conformation shown at B. By successive operations this may be pressed into successively elongated shapes which may include those shapes shown at C, D and E.

The shaping of the member may be conducted in any desired manner, for instance, in a punch press, wherein a suitably sized plunger serves to press the cup-like member through suitably proportioned and positioned dies. Desirably, when the cup-like member has been suitably elongated, its closed end is still furtherl narrowed, as indicated at F. In accordance with the invention, a portion of the member adjacent to its rim may be given an outwardly tapered conformation to provide a hub which will t firmly over the tapered nozzle of a hypodermic syringe. The hub walls may be readily thinned down during certain of the pressing operations in cases where a thick initial sheet was used or where the early pressing operations tendedto thicken the walls. I find in practice that a desirable wall thickness is from .015" to .020", but even when the thickness is considerably greater, the hub will have sufiicient flexibility to conform easily to tapered syringe nozzles of slightly varying contours. As likewise indicated at F, a bead may also be formed at the rim of the member. 'Ihe provision of the bead at this stage of the operation facilitates the holding of th e needle during subsequent ope erations.

As hypodermic needles as herein described may be of any standard design, I claim them as novel articles of that class.

What I therefore claim and desire to secure by Letters Patent is:

v1. A seamless, one-piece hypodermic needle formed from a blank of sheet material and cornprising a hollow hub portion of relatively large diameter for engagement with a syringe, a thinwalled cylindrical cannula portion having a sharpened penetrating end, and a hollow tapering portion connecting said hub and cannula portions, the outer surface of said connecting portion having a gradual concavely-curved mergence with the outer face of said cannula portion, and1 a gradual convexly-curved mergence with the outer face of said'hub portion, and the inner face of said connectingportion having a gradual convexly-curved kmergence with the'inner face of said cannula portion and a gradual concavely-curved mergence with the inner face of said hub portion, whereby the inner surfaces of the connecting portion, hub and cannula are continuously smooth for the free ow of' uid therethrough and whereby the bending strains applied to the cannula'are distributed over a substantial length of the needle.

2. A seamless, one-piece hypodermic needle formed from a blank of sheet material and comprising a hollow hub portion of relatively large diameter for engagement with a syringe, a thinwalled cylindrical cannula portion having a sharpened penetrating end and a hollow tapering portion connecting said hub and cannula portions, the outer face of said connecting portion having a gradual concavely-curved mergence with the outer face of said cannula portion, and the inner face of said connecting portion having a gradual convexly-curved mergence with the inner face of said cannula portion, whereby the inner surfaces of the connecting portion and cannula are free from seams and crevices wherein bacteria may collect and continuously smooth .to facilitate cleansing and sterilization and for the free flow of fluid therethrough and whereby the bending strains applied to the cannula are distributed over said connecting portion.

3. A seamless, one-piece hypodermic needle formed from a blank of sheet metal by successive drawing and swagingoperations to produce a relatively `thin resilient wall of substantially uniform metallic composition and homogeneity throughout and defining a hollow hub'portion of relatively large diameter for engagement with a syringe, a cylindrical cannula portionhaving a sharpened penetrating end, and a hollow tapering portion! connecting and merging with said hub and cannula portions. said connecting portion being formedy substantially as a concave conic figure and merging with the cannula in a curve tangential to the straight cylindrical wall of the cannula, the wail of said merging hub and connecting portions being of substantially the same thickness and of thel same configuration internally and externally, the inner merging surfaces of said cannula and connecting portion being free from seams and crevices-wherein bacteria may collect and continuously smooth for the free flow of fluid therealong, and said.

conic portion being of substantial length and transmitting and absorbing the bending strains applied to the cannula in use.

4. A seamless, one-piece hypodermic needle formed from a blank of sheet metal by succes-- sive drawing and swaging operations to produce a relatively thin resilient wall of substantially uniform metallic. composition and homogeneity throughout and defining a hub portion of relatively large diameter -and sumcient flexibility for engagement with syringe tips of slightly varying contours, a cylindrical cannula portion having a sharpened' penetrating end, and a tapering portion/connecting and merging with said hub and cannula portions, said connecting portion being formed substantially as a .relatively long cone, the apex ofthe cone gradually merging into the straight cylindrical wall of the cannula, the wallof' said merging hub and connecting portions beingv of substantially the same thickness andof the same configuration vinternally and externally, said connecting portion absorbing the bending strains`applied to said cannula portion in use, the inner merging surfaces of said cannula. and connecting portions being free from seams and crevices wherein bacteria may collect and continuously smooth for the free iiow of fluid therealong and to facilitate cleansing and sterilization.

5. A seamless, one-piece hypodermic needle formed from a blank of sheet metal by successive drawing and swaging operations to produce a relatively thin resilient wall of substantially uniform metallic composition and homogeneity throughout and dening a hub portion of relatively large diameter and sui'ilclent flexibility for engagement with syringe tips o1' slightly varying contours, a cylindrical cannula portion having a sharpened penetrating end, and a tapering portion connecting and merging with said hub and cannula portions. said connecting portion absorbing and transmitting the bending strains applied to the cannula during use and presenting a continuously smooth inner surface for the free ow of uid therethrough and to facilitate cleansing and sterilization, the inner merging surfaces of said cannula and connecting portions being free from seams and crevices wherein bacteria. may collect.

JESSE CONRAD SMITH.

Images