Metal working – Means to assemble or disassemble – To apply or remove a resilient article
Reexamination Certificate
2000-07-24
2001-05-01
Gerrity, Stephen F. (Department: 3723)
Metal working
Means to assemble or disassemble
To apply or remove a resilient article
C029S234000, C029S278000
Reexamination Certificate
active
06223408
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for placing an object in a syringe body. More particularly this invention concerns an apparatus for setting a partition piston or for filling a fluid into a syringe body.
BACKGROUND OF THE INVENTION
A standard prefilled hypodermic syringe comprises a tubular glass syringe body having a restricted front end that is provided with tip cap or needle. Around midway of its length the body is formed with a bypass passage constituted as a radially inwardly open and axially extending bypass groove. The interior of the syringe is subdivided by a front partition piston set just rearward of the bypass groove into a front compartment defined between the front partition piston and the front body end and a rear compartment bounded rearward by a rear piston fixed to a plunger that extends out a rear end of the body. A medicament, which may be a lyophilized powder or a liquid, is held in the front compartment and a solvent, typically water, is held in the rear compartment. For use the rear plunger is pressed forward so as to shift the front piston forward until it is level with the bypass passage which therefore opens into both the front and rear compartments, at which time the front piston stops moving while the liquid is forced by the rear piston through the bypass passage into the front compartment where it can mix with the medicament therein. Once the rear compartment is empty, the rear piston abuts the rear face of the front piston and the two move forward together to express the solution through the needle from the front compartment. The system can also be used with a medicament having two components that need to be mixed immediately before use.
Thus to make such a syringe it is necessary first to accurately set the front piston in place, then fill the rear compartment and set the rear piston and plunger in place, invert the assembly, and fill the medicament into the front compartment and install a tip cap or needle. Both of these operations—setting the rear piston in place and filling fluids into the compartments—are done by an apparatus which inserts a tube into the syringe body.
More particularly the front piston is set in place by compressing and fitting it into the front end of a setting tube whose outside diameter is slightly less than the inside diameter of the syringe body. This tube, with the piston fitted to its end, is inserted into the rear end of the piston until it is just rearward of where the piston should be set, then the piston is pressed forward out of the setting tube, whereupon its natural elasticity causes it to expand radially and set itself stably in place in the syringe body. Then the setting tube is withdrawn rearward.
To fill the fluid medicament or solid into one of the compartments, the syringe body is oriented with the compartment to be filled open upward and the filling apparatus inserts a filling tube down into the syringe. Once this tube is near the floor of the compartment, defined by the front face of the front piston, the medicament is fed out of the tube end. When dealing with a liquid, as when the apparatus is filling the rear compartment with solvent, it is standard to withdraw the filling tube upward as the liquid level rises in order to avoid turbulence.
In each of these operations it is essential that the syringe body be oriented accurately with respect to the setting or filling tube. Since, however, the syringe bodies are often formed of glass, they are gripped in holders with cushioned jaws so that the orientation of their axes cannot be guaranteed to lie on the center axis of the filling or setting tube. The result can be broken or scratched syringe bodies.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved apparatus for setting an object—a piston or a fluid—into a syringe body.
Another object is the provision of such an improved apparatus for setting an object—a piston or a fluid—into a syringe body which overcomes the above-given disadvantages, that is which inserts the tube into the syringe body exactly on the axis of the syringe body.
SUMMARY OF THE INVENTION
An object, e.g. a piston or a fluid medicament, is inserted into a tubular syringe body centered on a syringe axis and having a pair of ends by an apparatus having according to the invention a support movable axially forward toward and axially rearward away from the body and a tube extending along a sleeve axis generally parallel to the syringe axis, having a rear end fixed in the support and a front end fittable inside the syringe. A centering sleeve is formed centered on the sleeve axis with a generally frustoconical centering surface engageable with the rear body end surrounding the setting tube. This sleeve is displaceable axially on the support between a front position with the centering surface projecting axially forward past the tube front end and a rear position with the tube front end projecting axially forward past the centering surface. The support is displaced axially forward toward the body and thereby engages the centering surface coaxially with the body rear end. Thereafter the setting tube is pressed coaxially through the centering sleeve into the syringe body.
With this system, therefore, the centering sleeve serves for transversely displacing the front end of the setting tube and/or the rear end of the syringe body so that the syringe axis and the tube axis are perfectly aligned before the tube is actually inserted into it. Even if the syringe is not perfectly aligned with the setting tube, by the time the setting tube is advanced enough to poke into the rear syringe end, the two elements will be perfectly coaxial.
The centering surface can be axially flared toward the syringe body. Alternately it is axially tapered toward the syringe body. In the latter case the centering sleeve can be formed with a downwardly flared centering skirt centered on the tube axis and axially level with the centering surface. The taper of this skirt, which is normally of highly flexible material, is such that it engages the syringe rear end before the centering surface, something that is particularly useful with a syringe having a rolled rear-end rim since it allows the centering surface to be of downwardly tapering shape.
According to the invention a spring braced between the support and the centering sleeve urges the sleeve into the front position. The tube is normally somewhat elastically flexible so that its lower front end is somewhat transversely displaceable relative to the axes. The sleeve's front end can similarly move transversely so that when it fits with the syringe rear end, which can be offset transversely, it will move sideways and move the tube over too for perfect coaxial alignment.
The support in accordance with the invention is provided with a mounting sleeve generally centered on the tube axis and slidably surrounding the centering sleeve. Furthermore the centering sleeve and mounting sleeve define an axially extending space opening at the centering surface. The apparatus further has according to the invention means for aspirating gas in through the space. Thus any particles or droplets that might be generated by the filling operation will be aspirated right at the syringe rear end. To aid this aspiration one of the sleeves is formed with an axially extending and radially open groove extending a full length of the space and the centering surface is formed to seal tightly with the rear syringe end.
REFERENCES:
patent: 4141129 (1979-02-01), Martini
patent: 6012209 (2000-01-01), Whetstone
patent: 6108884 (2000-08-01), Casteman et al.
Hecht Anton
Steinbach Klaus
Vetter Udo J.
Arzneimittel GmbH Apotheker Vetter & Co. Ravensburg
Gerrity Stephen F.
Herbert Dubno Andrew Wilford
Wilson Lee
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