Dispensing – Plural sources – compartment – containers and/or spaced jacket – With discharge assistant for each source
Reexamination Certificate
2000-09-25
2001-11-06
Shaver, Kevin (Department: 3754)
Dispensing
Plural sources, compartment, containers and/or spaced jacket
With discharge assistant for each source
C222S567000
Reexamination Certificate
active
06311869
ABSTRACT:
BACKGROUND INVENTION
The invention relates to an apparatus for dispensing a mixed multi-component compound, in particular for dental purposes.
For producing multi-component dental impression compounds, use is made of units which are designed for accommodating a plurality of component-containing containers and for discharging the components from the containers. On the end side of the units, the containers have exposed outlet openings, to which the inlet openings of a mixing nozzle may be connected. The components come together in the mixing nozzle and leave the latter in the mixed state. Following the mixing operation, the compound hardens. This also applies to those components of the mixture which remain in the mixing nozzle once an impression-compound portion has been produced. Said mixing nozzle is configured such that the components only come together therein at a certain distance from the outlet openings of the cartridges, with the result that the hardening operation within the mixing nozzle remains restricted to a region sufficiently remote from the outlet openings of the containers. This makes it possible for a mixing nozzle which is used for producing an impression-compound portion and is rendered unusable by some of its contents hardening to be left on the unit in order to protect the outlet openings until the next portion is required. It is only then that the mixing nozzle is exchanged for a new one.
In a known unit disclosed in U.S. Pat. No. 5,333,760 the mixing nozzles are retained by a rotatable bayonet closure. A bayonet ring is retained on the mixing nozzle in an axially fixed but rotatable manner and, following the attachment of the nozzle to the outlet openings of the containers, is rotated in order to come into positively locking engagement with a pair of claws on the end side of the containers. The ring involves high outlay in terms of its connection to the mixing nozzle and because a comparatively large number thereof is required, specifically one for each mixing nozzle. This applies correspondingly to another known arrangement (EP-A-730 913), in which the bayonet coupling elements are arranged on the mixing-nozzle housing, which contains, in a rotatable manner relative to the housing, an insert which forms the inlet opening of the mixing nozzle. A design (DE-U-298 20 831) in which a locking means is arranged on the unit for the purpose of retaining the mixing nozzle involves less outlay. This means that it is not necessary for each individual mixing nozzle to be equipped with a bayonet element. However, it has been found that this design does not afford sufficient stability.
The apparatus according to
FIG. 4
from U.S. Pat. No. 4,753,536 comprises two component-containing containers which are fixed to one another and bear outlet connection stubs adjacent to one another on the end sides. It is possible to fit onto the outlet connection stubs a mixing nozzle which can be secured in the fitted position by a coupling device. The coupling device comprises a coupling plate which is borne by the outlet connection stubs and forms a guide, running transversely to the direction of the outlet connection stubs, for two coupling slides. The latter can be displaced into a closed position on the guide in opposite directions and bear coupling strips which, in the closed position, engage over a coupling flange of the mixing nozzle through 180° in each case.
SUMMARY OF THE INVENTION
The object of the invention is to provide an apparatus of the type mentioned in the introduction which has improved handling.
For this purpose, provision is made for the coupling slide to be in the form of a frame, and for displacement from the closed position into an open position, in which the coupling strips are free of the coupling flange, to be limited by contact with the coupling slide on a frame side.
The actuation of one coupling slide means reduced outlay in comparison with the actuation of two coupling slides, as in U.S. Pat. No. 4,753,536. Contact with the coupling slide on a frame side provides a defined open position, which allows the mixing nozzle to be attached to the outlet connection stubs and also allows the removal of the mixing nozzle. In the open position, the coupling slide remains on the unit and does not have to be attached laboriously again for a renewed closing operation. Considerably easier handling is achieved overall.
On its side which is directed towards the plate, the mixing nozzle is preferably bounded by a surface which rests over a large surface area on the surface of the plate.
Since the coupling plate is arranged directly on the containers and/or the connection stubs thereof, positional tolerances between the containers and the unit do not affect the securing of the mixing nozzle. Rather, the coupling forces are transmitted over an extremely short distance from the mixing nozzle to the outlet connection stubs. This makes it possible for the relevant components to be of less rigid design, consequently involving less outlay, than if the force transmission were to extend over a larger distance.
In the closed position, the coupling slide grips, by means of its coupling elements, the coupling flange of the mixing nozzle in such a way that the mixing nozzle is retained in sufficiently firm and sealed abutment against the outlet connection stubs and/or the coupling plate. Said coupling flange is gripped at least at two points which are offset by 180° in relation to one another. The coupling action expediently covers an angle of at least 180°, with the result that the coupling flange does not lack support over more than 180°. If a plurality of grip points are provided, these are spaced apart from one another by not more than 180°. If a single coupling element, which covers the border of the coupling flange continuously, is provided, this has to extend over at least 180° . If a plurality of coupling elements are provided, this is not necessary.
In one embodiment of the invention, the guide for the coupling slide is formed by two parallel strips on the coupling plate and two strips, engaging behind the same, of the coupling slide. The latter can thus be displaced in a translatory manner transversely to the direction of the outlet connection stubs. The guide strips are expediently continuous. Of course, however, it is also possible for in each case one of these to be made up of a plurality of spaced-apart protrusions. The slide has coupling strips in its region which interacts with the coupling flange of the mixing nozzle in the closed position. If, following the attachment of the mixing nozzle, the slide is pushed into its closed position, then the coupling strips are pushed over that part of the mixing-nozzle coupling flange which is adjacent to them in each case and thereby prevent the mixing nozzle from moving away from the coupling plate. As a result, the mixing nozzle is secured in the coupled position.
In a further embodiment, the coupling plate and the coupling flange have corresponding and adjacent coupling borders, and there is provided a coupling slide which can be pushed over the two borders, from the side, in order to enclose the same in the closed position of said coupling slide.
REFERENCES:
patent: Re. 34487 (1993-12-01), Keller
patent: 4767026 (1988-08-01), Keller et al.
patent: 4981241 (1991-01-01), Keller
patent: 5333760 (1994-08-01), Simmen
patent: 5924600 (1999-07-01), Keller
Horth Hans
Pauls Harald
Alix Yale & Ristas, LLP
Ernst Muhlbauer KG
Shaver Kevin
Wilatt Stephanie
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