US 3473524 A
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Oct. 21, 1969 J. DREWE 3,473,524
' SYRINGE AMPOULES Filed Jan. 23, 1967 i5 i4 l3 16 M 3 18 ited States Patent 3,473,524 SYRINGE AMPOULES John Drewe, Buntingford, England, assignor to Britampoula A.G., Chur, Switzerland Filed Jan. 23, 1967, Ser. No. 610,898 Claims priority, application Great Britain, Feb. 8, 1966, 5,55 4/ 6 6 Int. Cl. A611) /10; A61m 27/00 US. Cl. 128-2 5 Claims ABSTRACT OF THE DISCLOSURE CROSS-REFERENCES TO RELATED APPLICATIONS Reference is directed to copending patent application Ser. No. 383,777 filed on July 20, 1964 in the name of Arthur Bane, now US. Patent 3,340,869.
This invention relates to ampoules which are provided, or are adapted to be provided, at one end with a hypodermic needle so as to form a surgical hypodermic syringe or a device for taking and storing specimens of blood or other body fluids.
More specifically the invention is concerned with an ampoule comprising a collapsible chamber having two coaxially aligned, opposed, frusto-conical walls united at their base ends, one of which walls is resiliently deformable, when a predetermined axial compression force is applied to said chamber, from its normal expanded position, past a dead-centre position, into an inverted collapsed position, in which it lies close against the inner surface of the other wall, where it will be biased to remain until an axial tension force is applied to the chamber to return the said one wall past the dead-centre position to its expanded position. The inherent resilience of the said one wall of such an ampoule will act in opposition to the applied axial compression or tension force until the dead-centre position is reached, after which the direction in which the said inherent resilience acts will be reversed so that the said one wall will be biased to complete its movement into the collapsed or expanded position respectively.
The expression ampoule of the character referred to will be used hereafter and is used in this specification to mean an ampoule constructed and arranged to operate in the manner hereinbefore described.
An ampoule of the character referred to may be made of a transparent or translucent material and fitted at one end with a hollow needle so as to form a device taking samples of body fluids or a hypodermic syringe. When such an ampoule is to be used as part of a device for taking samples of body fluids, the collapsible chamber thereof may be the only collapsible portion which, when expanded, is capable of containing a gas or liquid, whereas, when such an ampoule is to be used as part of a hypodermic syringe, its collapsible chamber preferably constitutes one section, or some but not all sections of a concertina-type collapsible bellows, as in the case of the ampoule forming the subject of the aforementioned US. Patent 3,340,869.
An important advantage of which is achieved by using the ampoule according to my said copending patent application is that it enables the so-called aspiration test to be carried out reliably and safely.
The procedure for carrying out this aspiration test with a syringe comprising an ampoule according to said copending patent application is as follows. The syringe which has been prefilled with a predetermined quantity of a liquid drug is held preferably with the needle uppermost, and the independently collapsible bellows sections (or each such section if there is more than one) is collapsed, thereby expelling all air and surplus liquid from the ampoule, while leaving the remaining bellows sections filled with the liquid drug. The neede is then inserted into the patient, after which the independently collapsible bellows section (or each of such sections) is pulled out so that it returns to a partially expanded position. As a result of the return movement of the independently collapsible bellows section or sections, suction will be applied at the needle point. If blood is drawn into the ampoule, the user will know that the needle has penetrated a blood vessel. In cases where intravenous injection is required, the liquid drug can now be injected by collapsing the remaining bellows element or elements. Otherwise, e.g. in cases where intramuscular injection is required, the needle must be withdrawn and the test repeated at one or more different injection sites until no blood is drawn in as a result of the pulling out of the independently collapsible bellows section (or sections) to its (or their) partially expanded position.
It is of course important to ensure that the independently collapsible section or sections will remain in the fully collapsed condition while the needle is being inserted for purposes of the aspiration test. If, however, the deadcentre position of the or each independently collapsible section is close to its fully collapsed position, any distortion of the ampoule as a whole during insertion of the needle is liable to cause the or each independently collapsible element to return prematurely to its expanded position.
It is accordingly an object of this invention to provide an improved ampoule of the character referred to in which the dead-centre position is located sufliciently far from the fully collapsed position to avoid any appreciable risk of accidental or premature return of the independently collapsible element or elements to the fully expanded position.
With this object in view the invertible frusto-conical wall of the collapsible chamber of the ampoule according to this invention has an apex angle of between and while the other frusto-conical wall of the said chamber is not only stiffer (i.e. more resistant to deformation by an axial compression force applied to the ends of the container portion) than the invertible wall, but also has an apex angle which is not appreciably smaller and not more than 5 larger, than the apex angle of the invertible wall. Preferably, the apex angle of the said other wall is from 3.5 to 4.5 larger than that of the invertible wall.
The lower limit of 90 for the apex angle of the invertible wall and the limit of 5 for the extent to which the apex angle of the said other wall may exceed that of the invertible wall are imposed by practical considera tions. For example, if the apex angle of the invertible wall is made substantially less than 90, excessive force will have to be applied in order to deform this wall to its dead-centre position; also, if the apex angle of this wall is more than about 5 smaller than the apex angle of the other wall, then the invertible wall will not lie closely against the inner surface of the other wall. Furthermore, the said other wall, if its apex angle were to be more than 5 greater than that of the invertible wall,
would need to be made of substantial wall thickness or to be reinforced by substantial stifiening ribs in order to ensure that it is stiffer than the invertible wall.
It will of course be appreciated that the location of the dead-centre position of the invertible wall is also affected by other factors, including, the external diameter of the collapsible chamber, the material of which this chamber is made and the thickness of the invertible wall. Suitable materials include nylon polymers, polyethylene, polypropylene and surgical grades of polyvinyl chloride and the wall-thickness of the invertible wall will be so chosen, having regard to the nature of the material of which it is composed, the diameter of the bellows section and its apex angle, that the force required to deform this wall as far as the dead-centre point will not be greater than that which can be applied manually without undue effort. In the case of a syringe ampoule designed for administering a 1 cc. dose and made from a certain grade of polyethylene, it was found that a range of wall thickness from 0.005 to 0.02 inch was suitable when the bellows diameter was in the range of 0.6 to 0.8 inch.
According to a further feature of this invention, the collapsible chamber is closed at the smaller diameter end of the invertible frusto-conical wall by means of a substantially flat, circular platform which is thicker than the said invertible wall, but not so thick as to be incapable of undergoing substantial resilient deformation during collapse of the latter after the dead-centre point has been passed, and which has a diameter such that it will not interfere with the other wall as it moves into the fully collapsed position. The platform preferably has a centrally located, externally projecting operating stud formed integrally with it and the arrangement is advantageously such that, when the stud is pressed in, the platform will remain almost flat until the invertible wall has been collapsed beyond the dead-centre-point, whereupon it will progressively be deformed into a shape between that of a segment of a sphere and that of a cone.
A preferred embodiment of this invention will now be described by way of example with reference to the accompanying drawings:
FIGURE 1 is a partly sectioned side elevation of a surgical hypodermic syringe embodying an ampoule which is shown in the fully expanded position and FIGURE 2 is a fragmentary view of the ampoule with a section thereof collapsed.
The syringe has a bellows-type ampoule which comprises two zbellows sections 11 for containing a predetermined quantity of a liquid drug and a third bellows section 12 which is independently collapsible and expandable for carrying out what is commonly known as the aspiration test. A nozzle 13 projects coaxially from the end of the ampoule which is remote from the bellows section 12 and is fitted with a hypodermic needle 14 which has a removable cover 15 applied over it. At the other end of the ampoule is closed by a platform 16, the centre portion of which carries a stud having a head 17 and a neck 18.
The independently collapsible bellows section 12 is collapsible by applying to the stud 17, 18 an axial force which is smaller than that required to collapse the bellows sections 11 and furthermore it is so constructed and arranged that it collapses with an over-dead-centre action, i.e. an axial force applied to the head 17 of the stud in the direction towards the needle 14 displaces the platform 16 and the adjoining wall 21 to a position just beyond a dead-centre position (not shown), after which the wall 21 will continue to move in the same direction under the action of its own inherent resilience until it reaches the fully collapsed position shown in FIGURE 2.
To restore the bellows section 12 to the fully expanded position shown in FIGURE 1, the user pulls the stud 17, 18 in the direction away from the needle 1 until the platform 16 and wall 21 pass the dead-centreposition in the reverse direction, whereupon the expansion of the bellows section 12 will be completed by the continued movement of the wall 21 under the action of its own resilience.
Those features of construction and operation of the hypodermic syringe illustrated in FIGURES 1 and 2 which have been described so far are, in general, the same as corresponding features of the syrings described in and illustrated by FIGURES 1 and 2 of the specification of US. Patent 3,340,869. The present syringe, however, incorporates certain improvements which will now be described.
Referring to FIGURE 1, the apex angle 04 of the frusto-conical wall 21 is 96 while the apex angle 6 of the wall 22 is 4 larger, i.e. 100. Due to the relatively small size of its apex angle a of the wall 21, a corresponding high axial force must be applied against the head 17 of the stud in order to effect inversion of the wall 21 from the expanded position shown in FIGURE 1 into the collapsed position shown in FIGURE 2. As has previously been made clear the wall 22 must remain substantially undeformed during inversion of the wall 21 and in order to compensate for the reduction in stiffness which results from its larger apex angle 5, this wall 22 is made substantially thicker than the wall 21. It has been found that both the choice of 96 for the apex angle a of the wall 21 instead of a larger angle such as for example and the fact that the apex angle of the wall 22 p is 4 larger than the apex angle or have the effect of increasing the distance between the dead centre position of the wall 21 and its fully collapsed position and hence ensuring a more reliable over-dead-centre action and more positive retention of the wall 21 in its fully collapsed position.
Further improvements in the reliability of the overdead-centre action and in the stability of the wall 21 when in the fully collapsed position shown in FIGURE 2 are obtained by the construction and arrangement of the platform 16. This platform 16 is made substantially thicker than the wall 21, but not so thick as to prevent it from undergoing resilient deformation from the flat shape which it has when the wall 21 is in its expanded position (FIG. 1) to inwardly curved shape which it has when the wall 21 is in its collapsed position (FIGURE 2). The diameter of the platform 16 when fiat is somewhat less than that of the constricted opening between the wall 22 and its junction with the adjoining wall 23 of the nearer bellows element 11. The neck 18 of the stud is made of as small diameter as possible without rendering it liable to bend when axial pressure is applied to the head for the purpose of collapsing the wall 21. Since the neck 18 and the platform 16 are moulded integrally with each other, the angle between them is rounded as shown at 24. The radius of the rounded surface 24 is, however, as small as possible in order to avoid undue interference with the flexing of the platform 16 during the last part of its movement into the fully collapsed position.
When force is applied to the head 17 of the stud to collapse the bellows element 12, the platform 16 will remain almost flat until the dead-centre-position is reached and will thereafter be progressively deformed until, when the element 12 is fully collapsed, it assumes the shape shown in FIGURE 2 which is something between a segment of a hollow cone and a segment of a hollow sphere.
The present invention is not only applicable to ampoules for hypodermic syringes, as described above with reference to the drawings, but also to blood-sampling devices in which case there is no need to provide bellows sections corresponding to those shown at 11 in FIGURE 1 of the accompanying drawings.
1. A syringe ampoule, comprising:
a collapsible chamber having two coaxially aligned,
opposed, frusto-conical walls united at their base ends, one of said walls being resiliently deformable under a predetermined axial compression force from an expanded position into an inverted collapsed position in which it lies close against the inner surface of the other wall and having an apex angle of between 90 and 100, and
the other of said walls being stiffer than said one wall and having an apex angle which is not substantially smaller and not more than 5 larger than the apex angle of the said one wall, and
a mounting for a hypodermic needle provided on one end of said collapsible chamber and having a delivery and suction duct extending through it and communicating with the interior of said chamber.
2. A syringe ampoule according to claim 1, wherein the apex angle of the said other wall is from 3.5 to 45 larger than that of the said one wall.
3. A syringe ampoule according to claim 1, comprising in addition:
a substantially flat circular platform disposed with its main surfaces at right angles to the central axis of the collapsible container and closing said collapsible chamber at the smaller end of the said one wall,
said platform being thicker than the said one wall and having a diameter such that it remains out of contact with the inner surface of the said one wall when the collapsible chamber is collapsed,
an externally projecting operating stud formed integrally with and located centrally with respect to said platform, and
a nozzle constituting the said needle mounting and projecting axially from the smaller diameter end of said other Wall.
4. An ampoule comprising a collapsible chamber having two coaxially aligned, opposed, frusto-conical walls united at their base ends, one of which walls is resiliently deformable, when a predetermined axial compression force is applied to said chamber, from its normal expanded position, past a dead-centre-posltion, into an inverted collapsed position, in which it lies close against the inner surface of the other wall, where it will be biased to remain until an axial tension force is applied to the chamber to return the said one wall past the dead-centreposition to its expanded position, wherein the invertible frusto-conical wall of the collapsible chamber has an apex angle of between and while the other frusto-conical wall of the said chamber is not only stiffer than the invertible wall, but also has an apex angle which is not appreciably smaller and not more than 5 larger, than the apex angle of the invertible wall.
5. An ampoule according to claim 4 and comprising the addition: a substantially flat circular platform formed integrally with and extending transversely across the smaller diameter end of the said invertible frusto-conical wall, said platform being thicker than said invertible wall, and a centrally located externally projecting operating stud formed integrally with said platform, the arrangement being such that, when the stud is pressed in, the platform will remain substantially flat until the invertible wall has been collapsed beyond the dead-centreposition, whereupon it will be progressively deformed into a shape between that of a segment of a sphere and that of a cone.
References Cited UNITED STATES PATENTS 900,182. 10/1908 Mayers 128-232 X 2,673,561 3/1954 Peterson 128216 2,717,598 9/1955 Krasno 128-216 2,911,972 11/1959 Elinger 128-216 3,340,869 9/1967 Bane 1282 3,390,821 7/1968 Mullan 222-215 X RICHARD A. GAUDET, Primary Examiner MARTIN F. MAJESTIC, Assistant Examiner U.S. Cl. X.R. 128-216; 222-215