Hypodermic needle

Oct. 14, 1969

3,472,227

G. K. BURKE

HYPODERMIC NEEDLE

Filed Aug. 18, 1965

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INVENTOR

GEORGE K BURKE

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ATTORNEYS

3,472,227

Patented Oct. 14, 1969

United States Patent Office

472 227 HYPODERMIC NEEDLE George K. Burke, Bethlehem, Pa., assignor to Burron Medical Products, Inc., Bethlehem, Pa., a corporation of Pennsylvania

Filed Aug. 18, 1965, Ser. No. 480,617

Int. Cl. A61m 5/32

U.S. Cl. 128—221 9 Claims

ABSTRACT OF THE DISCLOSURE

The hypodermic needle includes four elements, namely the cannula, hub means, separate member and an adhesive substance. The hub means is of plastic material and has an opening therethrough extending from front to rear. The separate member which has an opening from front to rear is positioned within the hub and interlocked therewith with its front end spaced inwardly from the front end of the hub. The bore of the separate member includes an integral portion peripherally engaging the cannula at points spaced inwardly from its front end. The adhesive material substantially fills the space defined by said cannula and the adjacent portions of the hub and separate member for bonding the same in fixed operative position.

The present invention relates to a new and novel hypodermic needle, and more particularly to a hypodermic needle adapted to be used with a disposable syringe whereby the needle is ordinarily used one time and then discarded.

Since the hypodermic needle of the present invention is of the disposable type, it is essential from an economic standpoint that the manufacture of the needle be as inexpensive as possible. Hypodermic needles formed completely of metal have been used for many years, but it has been found that substantial reduction in cost can be obtained if certain portions of the needle are formed of a cheaper material such as plastic or the like.

The hypodermic needle as employed with conventional syringes generally includes two parts identified as the cannula portion and the hub portion. In order to provide a sufficiently sharp point to enable the needle to be inserted through human skin, the cannula portion for all practical purposes must be constructed of a metallic substance such as stainless steel.

On the other hand, the hub portion can be manufactured of other types of material, and the hub portion can be economically manufactured of a plastic substance such as polypropylene and the like.

It accordingly appears that the most desirable arrangement from an economic standpoint is to provide a hypodermic needle including a cannula portion of metal and a hub portion of plastic. However, when these two substances are employed in combination, it is difficult to provide a suitable means for securing the parts together. The most suitable substance for securing the metal cannula portion and the plastic hub portion together seems to be an adhesive substance such as an epoxy resin or the like. Conventional adhesive substances of this type have a good affinity for the metallic cannula portion, or in other words, the adhesive substance will form a very good bond with the metal. On the other hand, this type of adhesive substance does not form a particularly good bond with the plastic substance, although it is bonded thereto to a cerain extent.

A particular problem then arises as to the manner in which a sufficiently good connection can be obtained with the plastic hub portion in order that the hypodermic needle may provide an adequate interconnection between the cannula portion and hub portion so that it can pass the pull test and push test ordinarily required for the needle to meet minimum standards required in the medical field. It is apparent that the cannula means must be fixed with respect to the hub means to a sufficient extent ₅ that the cannula means will not move into the hub means when the cannula portion of the needle is inserted into a bottle or into the skin of a patient. The hub means and the cannula means are accordingly provided with directly contacting interengaging portions which impede 10 relative movement therebetween. These interengaging portions will tend to impede any relative movement and therefore will resist movement of the cannula means into the hub means as well as resist movement of the cannula means out of the hub means since it is also apparent that 15 it is necessary for the cannula means to remain in the hub means when the needle is withdrawn from a bottle or a patient’s skin.

The problem of obtaining a sufficiently good interconnection between the cannula means and the plastic hub portion is compounded by the fact that the adjacent surfaces of the cannula means and the hub portion are of very small dimension thereby providing a very small area for obtaining the necessary holding power between the parts. In a typical example wherein the cannula means may have a diameter of no more than approximately .040 inch, and further wherein the length of the adjacent surfaces on the cannula means and the hub portion are on the order of .225 inch in length, the total area available for obtaining a good interconnection between the cannula portion and the hub portion is only about 0.28 square inch. It is evident that this very small area does not afford a sufficient contact area for obtaining a very effective adhesive bond.

In order to assure that the necessary holding power will be obtained between the cannula portion and the hub portion, the present invention incorporates a novel structural arrangement such that the adhesive substance is in contact with a maximum area of the cannula means to provide the greatest possible bond therewith, and further wherein the hub means incorporates a novel arrangement for providing an effective mechanical interconnection between the body of the adhesive substance and the hub means. The hub means in fact defines a holding surface which engages against the body of the adhesive substance to maintain the cannula means in operative position and to resist movement of the cannula means out of the hub means.

A number of different modifications are illustrated herein, and the holding means for retaining the cannula means in the bore of the hub means may comprise the body of adhesive substance bonded both to the cannula means and the hub means and further having a mechanical interconnection with the hub means.

In addition to providing the necessary mechanical interconnection between the hub means and the cannula means, the arrangement of the present invention also ensures that an effective liquid-tight seal will be provided between these components so as to prevent any liquid from leaking between the cannula means and the hub means which is of course an important feature in any hypodermic needle. The interconnection will of course also be an air-tight arrangement so as to prevent air or any other gas from leaking past or between the hub portion and the cannula portion.

Certain portions of the hub means, which may be integral either with the main body portion of the hub means or the separate member incorporated in some forms of the hub means are adapted to be contacting engagement with portions of the outer surface of the cannula means so as to ensure proper alignment of the cannula means with respect to the hub means and to resist any tilting or

3,472,227 canting movement of the cannula means with respect to the hub means.

An object of the present invention is to provide a new and novel hypodermic needle of the disposable type which can be manufactured as economically as possible.

Another object of the invention is the provision of a hypodermic needle which is capable of passing the standard pull tests and push tests required in the medical field.

Still another object of the invention is to provide a hypodermic needle which employs relatively inexpensive materials which are ordinarily incompatible with one another and difficult to combine in an effective needle structure.

A still further object of the invention is to provide a hypodermic needle including a metallic cannula portion and a plastic hub portion interconnected by an adhesive substance and wherein a novel arrangement is incorporated for inserting a good mechanical interconnection between the adhesive material and the plastic material of the hub portion.

Yet another object of the invention is to provide a hypodermic needle including a metallic cannula portion, a plastic hub portion, and an adhesive substance to secure the portions together and wherein the arrangement is such that the adhesive substance will contact a maximum area of the cannula portion.

Yet a further object of the invention is the provision of a hypodermic needle including separate cannula and hub portions and wherein means is provided for forming an effective liquid and gas-tight seal between the cannula portion and the hub portion.

Still another object of the invention is to provide a hypodermic needle which is quite simple and inexpensive in construction, and yet which is quite efficient and reliable in use.

Other objects and many attendant advantages of the invention will become more apparent when considered in connection with the specification and accompanying drawings, wherein:

FIG. 1 is a longitudinal section through a further modified form of the invention;

FIG. 2 is a sectional view taken substantially along line 2—2 of FIG. 1 looking in the direction of the arrows;

FIG. 3 is an exploded view of certain of the components illustrated in the structure shown in FIG. 1;

FIG. 4 is a longitudinal section through a still further modified form of the invention; and

FIG. 5 is an exploded view of certain of the components illustrated in the structure shown in FIG. 4.

Referring now particularly to FIGS. 1 through 3 inclusive, the invention is illustrated wherein the hub means is indicated generally by reference numeral 600, and the cannula means is indicated generally by reference numeral 602. The hub means may be formed of a suitable plastic such as polypropylene, and the cannula means may be formed of stainless steel and the like. The cannula means includes a substantially cylindrical main body portion 604 which terminates in a relatively flat end portion 606 which extends substantially perpendicular to the longitudinal axis of the cannula means.

Hub means 600 is provided with an outer surface 610 which tapers to the left as seen in FIGS. 1 and 3 and which may be provided with oppositely extending flanges 612 at one end thereof. Surface 600 joins with an inwardly tapered surface 614 which in turn joins with a generally hexagonal shaped outer surface portion 616 which in turn joins with rather sharply tapered end portion 618 which joins finally with a small generally cylindrical surface 620 at the terminal end of the outer surface of the hub means.

Hub means 600 has a bore formed completely therethrough and opening through opposite ends thereof, the bore opening at one end and tapering inwardly along a surface 630 which joins with a surface 632 which tapers to the left as seen in FIG. 4, a groove indicated generally by reference numeral 634 being provided in surface 632 and adjacent surface 630. The groove is defined by a pair of reversely angled surfaces 636 and 638 which define angles of approximately 20 degrees with the adjacent surface 632 and are joined by generally cylindrical surface 640.

A more sharply tapered bore surface 644 joins with tapered surface 632, and a surface 646 of polygonal shape and which may for example be octagonal in configuration as seen most clearly in FIG. 2, joins with surface 644. A holding surface 648 is provided at one end of the bore, and a pair of diametrically opposite radially inwardly extending ribs 650 are provided. A generally cylindrical bore portion 652 is provided adjacent holding surface 648 and joins with an outwardly flared surface 654 which defines the end of the bore through the hub means.

The holding means of this form of the invention includes a separate member indicated generally by reference numeral 660 and having a pair of outer surfaces 662 and 664 joined by a peripherally extending outwardly directed rib indicated generally by reference numeral 666. This rib 666 includes a first surface 668 extending angularly from surface 662 and a second surface 672 extending angularly from surface 664, surfaces 668 and 672 being joined by a generally cylindrical surface 670. Surface 668 defines an angle of approximately 30 degrees with respect to surface 670, and surface 672 describes an angle of approximately 20 degrees with respect to surface 670.

Rib means 666 is adapted to fit snugly within the groove means 634 in the hub means for securing the separate member in operative position as seen in FIG. 1.

Surface 664 joins with an inwardly tapered surface 676 adapted to fit flush against surface 644 of the hub means, and surface 676 joins with a surface 678 of generally octagonal configuration which is adapted to fit snugly within surface 646 of the hub means. Surfaces 646 and 678 provide interlocking engaging geometric surfaces to provide a very effective seal therebetween.

Separate member 660 has a bore formed completely therethrough, this bore including a first surface 680 which tapers inwardly to the left as seen in the drawings from the open end thereof and which joins with a generally cylindrical bore portion 681 which in turn joins with an inwardly tapered surface 682 which in turn joins with a generally radially extending surface 683. Three substantially equally spaced inwardly directed ribs 684 are provided and extend inwardly from surface 682.

A pair of reversely tapered surfaces 685 and 686 extend to the left from a central opening provided through radial wall 686 and surface 684 joins with an outwardly flared surface 687. These surfaces cooperate to provide a pair of spaced annularly extending ribs 688 and 690 which are adapted to engage spaced portions of the outer surface of a cannula means for impeding relative movement between the cannula means and the hub means when in assembled relationship.

Surface 687 joints with an outwardly flared surface 692 which in turn joins with a generally cylindrical surface 694 at the opposite end of the bore through the separate member.

As seen in FIG. 1, separate member 660 has been inserted in operative position within the hub means and is held in place by the interengaging rib and groove means. The cannula means has been inserted in position such that the cylindrical body portion of the cannula means is snugly received and engaged by the rib portions 688 and 690 of the separate member. This will serve to impede relative movement between the cannula means and the hub means.

In addition a body of suitable adhesive material is provided, indicated by reference numeral 696. It will be noted that the adhesive material is in intimate contact with the outer surface of the cannula means and substantially fills the space between the outer surface of the

3.472.227 cannula means and the adjacent portions of the hub means and separate member. It is evident that the adhesive substance will fill in the space around the ribs 650 and will engage the holding surface 648 to firmly hold the cannula means in operative position and to prevent removal thereof from the hub means.

It should be noted that the surface 680 of the separate member may comprise a standard Luer taper such that the barrel of the syringe is adapted to fit snugly within the Luer taper portion of the separate member. With such an arrangement, there is no possibility of any medicament within the syringe leaking around the separate member and between the outer surface of the separate member and the inner surface of the surrounding hub portion.

In a typical example wherein the hub portion 600 may have an over-all length of 0.596 inch, the outer diameter of the right-hand end of the body portion may be approximately 0.246 inch, and the inner diameter of the bore portion at the intersection of surfaces 630 and 636 may be approximately 0.203 inch. The center of surface 640 may be spaced a distance of approximately 0.046 inch from the right-hand edge portion of the body means, and the groove means may have a depth of approximately 0.006 inch from surface 632.

The octagonal surface 646 may have a diameter from one corner to an opposite comer thereof approximately 0.140 inch and may have a length of approximately 0.168 inch. The surface 652 may have a longitudinal dimension of approximately 0.010 inch and a diameter of approximately 0.095 inch. The octagonal surface 646 may also taper slightly toward the left as seen in the drawings.

The separate member 660 may have an over-all length of approximately 0.540 inch, and the outer diameter thereof at the right-hand portion thereof may be approximately 0.205 inch. The rib portion 666 may be located such that the center of surface 670 is spaced a distance of approximately 0.046 inch from the right-hand edge portion of the separate member.

The Luer taper surface 680 of the separate member may have a longitudinal dimension of approximately 0.250 inch, while the surface 682 may have a longitudinal dimension of approximately 0.046 inch. The outer hexagonal surface 678 of separate member may also be slightly tapered and may have an outer diameter at the left-hand end portion thereof of approximately 0.132 inch. The surface 694 may have an inner diameter of approximately 0.100 inch. Each of the rib portions 688 and 690 may have an inner diameter of approximately 0.032 inch, and each of rib portions may be spaced apart a distance of approximately 0.046 inch.

A particular advantage of the modification shown in FIGS. 1 through 3 is the fact that the two spaced rib portions 688 and 690 permit use of cannulas of different outer diameter due to the inherent resilience of these rib portions which are adapted to tightly frictionally engage cannula means of slightly different size.

Referring now particularly to FIGS. 4 and 5, a modified form of the invention is illustrated wherein the hub means is indicated generally by reference numeral 700, and the cannula means is indicated generally by reference numeral 702. The hub means may be formed of a suitable plastic material such as polypropylene, and the cannula means may be formed of stainless steel and the like. The cannula means is substantially identical to those previously described and includes a substantially cylindrical main body portion 704 which terminates in a relatively flat end portion 706 which extends substantially perpendicular to the longitudinal axis of the cannula means.

As seen particularly in FIG. 5, the hub portion 700 includes an outer surface portion 710 which tapers inwardly toward the left as seen in FIG. 5 and which joins with a generally cylindrical surface 712 which in turn joins with a sharply tapered outer surface 714 which further joins with a generally cylindrical surface 716.

A bore is formed completely through portion 700 and opens at one end thereof and tapers inwardly as indicated at 720, this inwardly tapering surface joining a groove indicated generally by referfence numeral 722 and defined by reversely tapered surfaces 724 and 726 joined _g by generally cylindrical surface 728. A generally cylindrical bore surface 730 extends to the left from the groove 722, and a holding surface 732 is provided at one end of the bore.

A pair of diametrically opposite radially inwardly exj₀ tending ribs 734 are provided. A generally cylindrically bore portion 736 is formed adjacent the holding surface 732 and joins with an outwardly flared surface 738 which defines the end of the bore through the hub means.

A separate member is indicated generally by reference 15 numeral 740 and includes an outer surface 742 which tapers slightly to the left as seen in FIG. 5, a pair of flanges 744 being provided at the outer end thereof. Surface 742 joins with generally radially extending outer surface 746 which in turn joins with an inwardly tapered 2o outer surface 748. Surface 748 terminates in a peripherally extending outwardly directed rib indicated generally by reference numeral 750 and being defined by a pair of reversely tapered surfaces 752 and 754 which are joined by a generally cylindrical connecting surface 756. Each of sur25 faces 754 and 752 may define an angle of approximately 20 degrees with surface 756. An outer surface 758 which is generally cylindrical extends from the rib portion 750 to the left hand portion of the separate member as seen in the drawings.

Separate member 740 is provided with a bore formed completely therethrough and the bore opens at one end thereof and tapers to the left along a surface 760 which may comprise a conventional Luer taper surface. Surface 760 joins with an inwardly tapered surface 762.

Surface 762 then joins with a generally cylindrical surface 764 which in turn joins with a tapered surface 765. A reversely tapered surface 766 joins with another generally cylindrical surface 767. Reversely tapered surfaces 765 and 766 are joined by a generally cylindrical surface 40 768. Surface 768 provides peripherally extending inwardly directed rib which is adapted to engage the outer surface of the cannula means frictionally for impeding relative movement between the cannula means and the hub portion.

Surface 766 joins with a generally radially extending 45 surface 770 which in turn joins with a generally cylindrical surface 772 which further joins with an outwardly flared surface 774 defining the opposite end portion of the bore through the separate member.

As seen particularly in FIG. 4, the separate member 50 has been inserted in operative position within the hub means, and the cannula means has been inserrted in position such that the cylindrical body portion thereof is snugly received within the bore in the separate member and is frictionally engaged with the rib portion 768. This 55 serves to limit relative movement between the hub portion and the cannula means and to hold the cannula means firmly in operative position. In addition, a body of suitable adhesive material is provided similar to that previously described, and the adhesive material is indicated by ref₆₀ erence numeral 780. It will be noted that the adhesive material in this modification is also in intimate contact with the outer surface of the cannula means and substantially fills the space between the outer surface of the cannula means and the adjacent portions of the hub means and 65 separate member. It is evident the adhesive substance will fill in the space around rib 732 and will engage the holding surface 734 to firmly hold the cannula means in operative position and to prevent removal from the hub means.

In a typical example, the separate member 740 may have an over-all length of 0.561 inch with an outer dimension at the right-hand portion of surface 742 of approximately 0.220 inch and an outer dimension at the left-hand end portion of the separate member of approxi75 mately 0.120 inch. The surface 758 may have a longi

3,472,227 tudinal dimension of approximately 0.112 inch, and the rib 750 may have a longitudinal dimension of approximately 0.078 inch.

The distance from the left-hand end of surface 762 to the radial surface 770 may be approximately 0.093 inch, while the cylindrical surface 768 may have a longitudinal dimension of approximately 0.005 inch and the inner diameter of surfaces 764 and 777 may be approximately 0.036 inch. Surface 772 may have an inner diameter of approximately 0.046 inch. jq

It is apparent from the foregoing that there is provided according to the present invention a new and novel hypodermic needle of the disposable type which can be used with disposable syringes and further which can be manufactured in an extremely economical manner. Both the 15 cannula means and hub means are formed in a very inexpensive manner and employ cheap materials which are ordinarily incompatible and difficult to combine. The structural arrangement is such as to enable the needle assembly to pass standard pull tests and push tests as 20 required. The cannula means in each case is formed of a metallic substance such as stainless steel and the hub means is formed of a relatively inexpensive substance such as plastic. The various needle assemblies ensure that an effective liquid-tight and gas-tight seal will be pro- 25 vided between the hub means and the cannula means. In those modifications which employ a body of adhesive material for securing the hub means and cannula means together, a unique structural arrangement is incorporated for providing an effective mechanical interconnection be- 30 tween the body of adhesive substance and the hub means, it being considered that the adhesive substance ordinarily provides a sufficient bond with the metallic substance of the cannula means without the necessity of providing additional interconnecting means. The arrangement is 35 such that a maximum area of contact between the adhesive substance and the cannula means is afforded in the various modifications of the invention to enhance the bonding effect with the cannula means. The hypodermic needle of the present invention is quite simple and in- ⁴⁰expensive in construction, and yet at the same time is quite efficient and reliable in use.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the 45 invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims. 50