U.S. patent number 3,695,478 [Application Number 05/062,389] was granted by the patent office on 1972-10-03 for flexibly deformable stopper for a hypodermic syringe.
Invention is credited to Hendrik Alle Post, Tjwan Khing Sie.
United States Patent |
3,695,478 |
Sie , et al. |
October 3, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
FLEXIBLY DEFORMABLE STOPPER FOR A HYPODERMIC SYRINGE
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.
Inventors: |
Sie; Tjwan Khing (Emmasingel,
Eindhoven, NL), Post; Hendrik Alle (Emmasingel,
Eindhoven, NL) |
Family
ID: |
19807732 |
Appl.
No.: |
05/062,389 |
Filed: |
August 10, 1970 |
Foreign Application Priority Data
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Aug 23, 1969 [NL] |
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6912907 |
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Current U.S.
Class: |
604/200; 220/277;
220/800; 604/201 |
Current CPC
Class: |
A61M
5/286 (20130101); B65D 51/002 (20130101) |
Current International
Class: |
A61M
5/28 (20060101); B65D 51/00 (20060101); B65d
039/12 (); B65d 041/00 (); A61m 005/28 () |
Field of
Search: |
;128/218,213,215,216,220,217,272,276 ;215/47,52 ;220/42,42B |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: McGowan; J. C.
Claims
What is claimed is:
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.
Description
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 different
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--I 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.
The stopper 1 shown in FIGS. 1 and 2 comprises a neck 3 having a
central channel 5 which is closed at one end 7 by a flat
thin-walled diaphragm 9 and which is open at the other end 11. At
the closed end 7 the stopper comprises an annular flange 13 which,
in the example shown, has a rhombic profile 15. The four sides 17,
19, 21 and 23 of the profile 15 form describing lines of four
conical surfaces which bound the front face 25, the outer
circumference 27, the rear face 29 and the inner circumference 31,
respectively, of the flange. The front face 25 and the rear face 29
extend in the same direction and enclose an acute angle .alpha.
with the center line 33 of the neck 3, the outer edge 35 of the end
face 25 projecting beyond the front side 37 of the diaphragm 9. The
apices 39 of the end face 25 and the rear face 29 lie on the part
of the center line 33 facing the open end 11. The outer
circumference 27 and the inner circumference 31 likewise extend in
a same direction and enclose an acute angle .beta. with the center
line 33, their apices 41 being situated on the part of the center
line 33 remote from the open end 11. The inner circumference 31
which adjoins the neck 3 is connected to the outer circumference 45
of the neck 3 by a rounded section 43 having a wall thickness d
which is smaller than the maximum axial wall thickness D of the
flange 13. Viewed in the cross-section, the radial distance R from
the apex 35 projecting beyond the front side 37 to the center line
33 is larger than the corresponding distance r of the apex 49
facing the neck 3. The neck 3 furthermore comprises a number of
longitudinal 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. The hypodermic syringe 53
comprises a cartridge 55 and adjoining flange 59. A hollow
injection needle 61 is secured in a needle holder 63 which
comprises a chamber 65 and has a flanged portion 67. During
assembly, the neck 3 of the stopper 1 is inserted in the narrowed
neck 57 of the cartridge 55, the longitudinal ribs 51 facilitating
the insertion of the stopper. The flange 13 of the stopper 1
becomes situated between the flange portion 67 of the needle holder
63 and the flange 59 of the cartridge 55 in which, as is shown in
FIG. 3, the outer edge 35 of the end face 25 contacts the flange
portion 67 first, while the inner edge 49 of the rear face 29
contacts the flange 59. Due to the rhombic 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 the hypodermic syringe 53 with the stopper 1 in the
mounted clamped condition in which the flange 13 is compressed
between the flange portion 67 and the flange 59 by means of a
bent-over collar 69. In this example the collar 69 forms part of
the needle holder 63 which is manufactured from metal. Clamping the
needle holder 63 to the cartridge 55 can be effected in any other
conventional manner, for example, by means of a separate ring
separated from the needle holder 63, in which the needle holder may
be manufactured from a synthetic resin. During clamping of the
needle holder 63 to the cartridge 55, the flange 13 experiences a
bending action on the part situated at the area of the rounding 43,
so that the originally conical end face 25 becomes located in the
flat plane of the flange portion 67 and the rear face 29 becomes
located in the plane of the flange 59. Due to this bending of the
flange 13, the diaphragm 9 is tautly stretched and subjected to a
pre-stress after which the stopper 1 is clamped in this condition
by bending over the collar 69. As a result of the free space
available between the flange 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 the hypodermic syringe 53, filled, for example, with a
medicament 71, a pressure is exerted on the medicament 71 in the
cartridge 55 by means of the piston 73, so that the diaphragm 9
begins to bulge into the chamber 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 the diaphragm 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 the stopper 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, the needle 61 comprises, at its end facing the diaphragm
9, a sharp tip 75 which extends in the chamber 65. The bursting of
the diaphragm is introduced by the contact with the sharp tip.
Instead of providing the needle 61 with a sharp tip 75, other sharp
elements known per se may be provided in the needle holder 63.
FIG. 5 shows another embodiment of the stopper according to the
invention. This stopper 1 likewise comprises a flange 13 having a
rhombic profile 15, the front face 25 and the rear face 29 of which
enclose an acute angle .alpha. with the center line 33 of the neck
3, said faces forming parts of conical surfaces the apices 39 of
which are situated on the part of the center line facing the open
end 11. The outer circumference 77 extends parallel to the center
line 33, while the rear face 29 adjoins the cylindrical outer
circumference 45 of the neck 3 directly or via an annular chamber
78. In this embodiment also a bending of the flange 13 relative to
the neck 3 takes place during the clamping operation of the stopper
1 so that the diaphragm 9 comes under a pre-stress.
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.
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