US3695478A - Flexibly deformable stopper for a hypodermic syringe - Google Patents

Abstract

A flexibly deformable stopper for a hypodermic syringe consisting of a neck having a central channel, a diaphragm at one end of the neck and an annular flange having a quadrangular cross-section at the closed end. The front face and the rear face of the flange enclose an acute angle with the neck and extend in the same direction, the outer edge projecting beyond the front side of the diaphragm in such manner that during the clamping operation of the flange the diaphragm is pre-stretched.

Description

United States Patent [151 3,695,478 Sie et al. [4 1 Oct. 3 1972 [54] FLEXIBLY DEFORMABLE STOPPER 2,848,130 8/1958 Jesnig ..215/52 FOR A HYPODERMIC SYRINGE 2,847,996 8/1958 Cohen et al ..128/218 M [72] Inventors: gjvtvtalmolhigg Sie; Henldl'ill; g; P081, FOREIGN PATENTS OR APPLICATIONS o mmasm e in oven, Netherlands g 990,823 9/1951 France ..215/52 [22] Filed: 1970 Primary Examiner--Richard A. Gaudet [21] Appl. No.: 62,389 Assistant Examiner-J. C. McGowan Attorney-Frank R. Trifari [30] Foreign Application Priority Data [57] ABSTRACT Aug- 23, Netherlands A deformable for a Syr inge consisting of a neck having a central channel, a [52] US. Cl ..2l5/52,12228(;/24l28l?i 11228521752, diaphragm at one end of the neck and an annular flange having a quadrangular cross-section at the i qf g g g g closed end. The front face and the rear face of thel 1 fi gfi fi 25/117 flange enclose an acute angle with the neck and extend in the same direction, the outer edge projecting beyond the front side of the diaphragm in such [56] References Cited manner that during the clamping operation of the UNITED STATES PATENTS flange the diaphragm is pre-stretched. 3,424,155 1/1969 Sarnoff ..128/218 NV 3,091,240 5/ 1963 McConnaughey et 4 Claims, 5 Drawing Figures a1. ..128/218 NV L i 1 I 7 PATENTEDuura m2 3.6953178 SHEET 1 0F 2 4 /41R 13 35 19 17 37 9 25 1 1 1Km D d j r 45 1 51 I 5w 33I T 1 Fig.1

INVENTORS HENDRIK A. POST B Y TJWAN K. SIE

33K, PAM t:

AGENT FLEXIBLY DEFORMABLE STOPPER FOR A I-IYPODERMIC SYRINGE The invention relates to a flexibly deformable stopper for a hypodermic syringe consisting of a neck having a central channel which is open at one end and is closed at the other end by a diaphragm and comprising at the closed end an annular flange having a quandrangular cross-section.

Such stoppers are used in hypodermic syringes which have a cartridge forming a piston, which may be filled with a medicament. In this syringe the stopper separates the cartridge from the injection needle which is supported by the cartridge.

Communication of the medicament between the cartridge and the needle is known to be effected by causing the diaphragm to burst as a result of a fluid pressure which is exerted on the diaphragm by means of the piston, in which the diaphragm is stretched and is or is not contacted, prior to bursting, with the sharp end of the needle or with other perforation elements. The stoppers used in said syringes should be of such a construction that, during the injection of a medicament, clogging of the needle is prevented and, during the aspiration of moisture or blood, the flow aperture of the diaphragm remains free.

Stoppers of the known type, are of such a construction that due to the deformation of the flange during the clamping-in thereof between the cooperating parts of the hypodermic syringe, the flange will expand in the direction of the center line of the stopper so that the diaphragm is compressed in the radial direction and is not tautly stretched in the clamped condition of the stopper. The compression of the diaphragm results in requiring it to be considerably stretched in order to cause it to burst. As a result of this the operation of the diaphragm during the injection and the aspiration is adversely affected.

It is the object of the invention to provide a stopper for a hypodermic syringe which will overcome the disadvantages of prior stoppers and which is of such a construction that the flow aperture of the burst diaphragm is maintained unobstructed in all circumstances, both during the injection of a medicament and during the drawing of blood or fluid.

In accordance with the present invention, the above stated object is achieved by providing that both the front face and the rear face of the flange enclose an acute angle with the neck and said faces extend in the same direction, the outer edge of the front face projecting beyond the front of the diaphragm remote from the neck, all this in such manner that, during the clamping operation of the flange, the diaphragm is pre-stretched. During the clamping operation of the stopper between two flanges of the hypodermic syringe, the flange of the stopper is deformed and bent backwards in the direction of the open end of the neck so that the diaphragm is tautly stretched (pre-stressed). Because the diaphragm is pre-stressed the relaxation after expanding the material from which the stopper is manufactured is compensated for. The burst diaphragm tends to shrink in the radial direction towards the flange, so that a flow aperture is obtained which remains free. Experiments have proved that this is possible with stoppers manufactured from various materials having different medical properties and dif ferent relaxation properties.

According to a preferred embodiment of the stopper in accordance with the present invention, the flange has a substantially rhombic cross-section the sides of which form describing lines of four conical surfaces, the apices of which are situated on the center line of the neck. As a result of the flange design, space is created on its circumference to accommodate the radial expansion of the flange during the clamping operation. During the compression the flange is pressed radially to the outside, so that the prestress of the diaphragm is increased.

According to a further preferred embodiment of the stopper according to the invention, the face of the flange which adjoins the neck adjoins the outer circumference of the neck with a rounding. The stopper at the area of the transition has an axial wall thickness which is smaller than the maximum axial thickness of the flange. Due to the rounded transition between the flange and the neck a deformation of the neck is prevented. At the area of the transition, a bending of the flange relative to the neck occurs during the clamping operation in which the surface and the rear face of the flange contact the cooperating flanges of a syringe with the whole surface so that a good seal is obtained.

According to a further preferred embodiment of the stopper according to the invention, the radial distance, viewed in the cross-section, from the vertex of the flange projecting beyond the front side of the diaphragm to the center line is larger than the radial distance to the center line of the oppositely located vertex facing the neck. Due to the difference in the radial distances of the two vertices a lever action is obtained during the clamping operation of the flange as a result of which the stretching of the diaphragm is stimulated.

According to the invention the above-described stopper can advantageously be used in a hypodermic syringe comprising a cartridge which has at one end a narrowed neck with adjoining flange, a needle holder comprising a chamber and a hollow needle and a flange part near the end of the chamber remote from the needle, a stopper having a neck being provided in the narrowed neck of the cartridge, a flange of the stopper being clamped, by means of a connection part, between the flange part of the needle holder and the flange of the cartridge in a deformed condition and in a sealing manner. In this case the flange of the stopper is bent backwards relative to the neck so that the diaphragm is under a stretched condition.

In order that the invention may be readily carried into effect, it will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which FIG. 1 is a cross-sectional view of an embodiment of the stopper according to the invention taken on the line I-l of FIG. 2,

FIG. 2 shows the stopper viewed in the axial direction taken on the line II-II of FIG. 1,

FIG. 3 is a partial longitudinal cross-sectional view of a hypodermic syringe comprising a stopper according to the invention prior to clamping the flange;

FIG. 4 is a longitudinal cross-sectional view of the hypodermic syringe with the stopper in the clamped condition, and

FIG. 5 is another embodiment of a stopper according to the invention.

Thestopper 1 shown in FIGS. 1 and 2 comprises aneck 3 having acentral channel 5 which is closed at one end 7 by a flat thin-walled diaphragm 9 and which is open at theother end 11. At the closed end 7 the stopper comprises anannular flange 13 which, in the example shown, has arhombic profile 15. The foursides 17, 19, 21 and 23 of the profile form describing lines of four conical surfaces which bound thefront face 25, theouter circumference 27, therear face 29 and theinner circumference 31, respectively, of the flange. Thefront face 25 and therear face 29 extend in the same direction and enclose an acute angle a with thecenter line 33 of theneck 3, theouter edge 35 of theend face 25 projecting beyond the front side 37 of thediaphragm 9. Theapices 39 of theend face 25 and therear face 29 lie on the part of thecenter line 33 facing theopen end 11. Theouter circumference 27 and theinner circumference 31 likewise extend in a same direction and enclose an acute angle B with thecenter line 33, theirapices 41 being situated on the part of thecenter line 33 remote from theopen end 11. Theinner circumference 31 which adjoins theneck 3 is connected to theouter circumference 45 of theneck 3 by a rounded section 43 having a wall thickness d which is smaller than the maximum axial wall thickness D of theflange 13. Viewed in the cross-section, the radial distance R from theapex 35 projecting beyond the front side 37 to thecenter line 33 is larger than the corresponding distance r of theapex 49 facing theneck 3. Theneck 3 furthermore comprises a number oflongitudinal ribs 51, in the present example four such longitudinal ribs are provided.

FIG. 3 shows a part of a hypodermic syringe having a stopper, the flange of which is not yet clamped. Thehypodermic syringe 53 comprises acartridge 55 and adjoining flange 59. Ahollow injection needle 61 is secured in aneedle holder 63 which comprises achamber 65 and has a flangedportion 67. During assembly, theneck 3 of thestopper 1 is inserted in the narrowedneck 57 of thecartridge 55, thelongitudinal ribs 51 facilitating the insertion of the stopper. Theflange 13 of thestopper 1 becomes situated between theflange portion 67 of theneedle holder 63 and the flange 59 of thecartridge 55 in which, as is shown in FIG. 3, theouter edge 35 of theend face 25 contacts theflange portion 67 first, while theinner edge 49 of therear face 29 contacts the flange 59. Due to therhombic profile 15, free space is present between the conical surfaces of the flange and the adjacent wall parts of the hypodermic syringe in the non-deformed condition of the flange.

FIG. 4 shows thehypodermic syringe 53 with thestopper 1 in the mounted clamped condition in which theflange 13 is compressed between theflange portion 67 and the flange 59 by means of a bent-over collar 69. In this example thecollar 69 forms part of theneedle holder 63 which is manufactured from metal. Clamping theneedle holder 63 to thecartridge 55 can be effected in any other conventional manner, for example, by means of a separate ring separated from theneedle holder 63, in which the needle holder may be manufactured from a synthetic resin. During clamping of theneedle holder 63 to thecartridge 55, theflange 13 experiences a bending action on the part situated at the area of the rounding 43, so that the originallyconical end face 25 becomes located in the flat plane of theflange portion 67 and therear face 29 becomes located in the plane of the flange 59. Due to this bending of theflange 13, thediaphragm 9 is tautly stretched and sub jected to a pre-stress after which thestopper 1 is clamped in this condition by bending over thecollar 69. As a result of the free space available between theflange 13 and the adjacent wall parts, said flange, during the clamping operation, can expand towards the outside in a radial direction remote from the center line, so that the pre-stress is increased.

When using thehypodermic syringe 53, filled, for example, with amedicament 71, a pressure is exerted on themedicament 71 in thecartridge 55 by means of thepiston 73, so that thediaphragm 9 begins to bulge into thechamber 65, is subjected to a tensile stress and ultimately bursts, the tensile stress being mainly removed during bursting. On the basis of the relaxation power of flexible materials, a diaphragm tends to return to the original condition in a delayed manner. Since, however, in the stopper according to the invention thediaphragm 9 is pre-stretched, the relaxation influence is removed and even overcompensated in accordance with the material used. The diaphragm tends to shrink in a radial direction away from the center line, so that the burst diaphragm shows a flow aperture which remains free in all circumstances.

The construction of thestopper 1 is such that in most of the cases the diaphragm can be made to burst as a result of the fluid pressure. In order also to cause diaphragms having too large a wall thickness deviating from the required thickness to burst with certainty, theneedle 61 comprises, at its end facing thediaphragm 9, asharp tip 75 which extends in thechamber 65. The bursting of the diaphragm is introduced by the contact with the sharp tip. Instead of providing theneedle 61 with asharp tip 75, other sharp elements known per se may be provided in theneedle holder 63.

FIG. 5 shows another embodiment of the stopper according to the invention. Thisstopper 1 likewise comprises aflange 13 having arhombic profile 15, thefront face 25 and therear face 29 of which enclose an acute angle a with thecenter line 33 of theneck 3, said faces forming parts of conical surfaces theapices 39 of which are situated on the part of the center line facing theopen end 11. Theouter circumference 77 extends parallel to thecenter line 33, while therear face 29 adjoins the cylindricalouter circumference 45 of theneck 3 directly or via anannular chamber 78. In this embodiment also a bending of theflange 13 relative to theneck 3 takes place during the clamping operation of thestopper 1 so that thediaphragm 9 comes under a prestress.

The invention is not restricted to the examples described but also comprises other constructions, for example, a stopper in which the boundary lines of the profile are curved, a stopper in which the front face and the rear face of the flange do not extend in parallel, or a stopper the flange of which has the profile of a trapezium.

What is claimed is:

l. A stopper of flexibly deformable material for a hypodermic syringe comprising a neck having a central channel being open at one end thereof and closed at its other end, a diaphragm forming the closure at the closed end of said neck, an annular flange attached to said neck at its closed end, said flange having a quadrangular cross-section, a front face and a rear face extending in parallel directions and forming acute angles with the center line of the neck in the direction of the closed end, the outer edge of the front face projecting beyond the front of the diaphragm remote from the neck whereby the diaphragm will be stretched when said flange is clamped in the syringe.

2. The stopper according toclaim 1 wherein said flange has a substantially rhombic cross-section the sides of which form describing lines of four conical surfaces, the apices of which are located on the center line of the neck.

3. The stopper according toclaim 1 further comprising a rounded section connecting the face of the flange with the outer circumference of the neck, the axial wall thickness of said rounded section being smaller than the maximum axial thickness of the flange.

4. The stopper according toclaim 1 wherein the radial distance from said outer edge of the front face projecting beyond the front of the diaphragm to the center line of said neck is larger than the radial distance from the outer edge of the rear face closest to said neck to the center line of said neck.

732 33 I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3695478 v DatedOct 3 1972 I TJWAN KHING SIE ET AL It is Certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, after [7 Inventors: Tjwan Khing Sie; p

Hendrik Alle Post, both of Emmasingel, Eindhoven, Netherlands" Ineert: [73] Assignee U.S .Philips Corporation Signed and sealed this 8th day of May 1973.

Attest: v

EDWARD MQFLETCHERJR. ROBERT GOTTSGHALK Attesting Officer Commissioner of Patents

Claims (4)

1. A stopper of flexibly deformable material for a hypodermic syringe comprising a neck having a central channel being open at one end thereof and closed at its other end, a diaphragm forming the closure at the closed end of said neck, an annular flange attached to said neck at its closed end, said flange having a quadrangular cross-section, a front face and a rear face extending in parallel directions and forming acute angles with the center line of the neck in the direction of the closed end, the outer edge of the front face projecting beyond the front of the diaphragm remote from the neck whereby the diaphragm will be stretched when said flange is clamped in the syringe.

2. The stopper according to claim 1 wherein said flange has a substantially rhombic cross-section the sides of which form describing lines of four conical surfaces, the apices of which are located on the center line of the neck.

3. The stopper according to claim 1 further comprising a rounded section connecting the face of the flange with the outer circumference of the neck, the axial wall thickness of said rounded section being smaller than the maximum axial thickness of the flange.

4. The stopper according to claim 1 wherein the radial distance from said outer edge of the front face projecting beyond the front of the diaphragm to the center line of said neck is larger than the radial distance from the outer edge of the rear face closest to said neck to the center line of said neck.

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