Special receptacle or package – For mixing
Reexamination Certificate
2001-05-23
2003-04-08
Luong, Shian (Department: 3728)
Special receptacle or package
For mixing
C206S063500
Reexamination Certificate
active
06543611
ABSTRACT:
The present invention relates to a mixer capsule and a mixer unit which includes a mixer capsule, in particular for the production of a dental material.
Mixer capsules which are filled with two or more components in separate chambers by the manufacturer are used to produce mixtures of the components. The components are brought into communication and mixed with one another by the user, for example by the destruction of a wall separating the chambers.
Mixer capsules for the production of dental materials which are often mixed from a pulverulent component and a liquid component, the mixing operation usually taking place in a shaker unit, are known in the dental sector. The fully mixed substance is then discharged directly onto the working area, for example into a tooth cavity, through a discharge spout formed integrally on the mixer capsule.
DE 36 35 574 has disclosed a mixer capsule which is intended for the production of jointing and sealing compounds. In an exemplary embodiment described in this document, an auxiliary chamber which is present in the discharge piston is delimited, on the side which faces the main chamber of the capsule, by a sheet and, on the opposite side, by an auxiliary piston which is arranged displaceably in the discharge piston. In the starting state of the mixer capsule, as well as the second component, a mixer body is accommodated in the auxiliary chamber, which body initially serves to destroy the sheet by manual displacement of the auxiliary piston and then assists with the mixing operation. To allow the reduction in volume which is necessary for displacement of the inner piston together with ball, a gas cushion is provided in the mixing chamber.
In a further embodiment of the known mixer capsule, the mixer ball is initially situated in the main chamber. In this case, the auxiliary chamber which is present in the piston is closed off from the main chamber by means of a cover and on its rear side by a bellows. As a result of manual pressure being applied to the bellows, the cover is pressed away from the piston, so that the two chambers are brought into communication for the purpose of activation of the capsule.
In both cases, a dedicated working step which has to be carried out manually is required for activation of the capsule. Furthermore, a gas cushion is required in order to allow the reduction in volume which is required for removal of the cover.
In a multicomponent mixer capsule for dental purposes which is known from DE 94 00 374 U1, a first component is contained in a mixing chamber and a second, liquid component is contained in a film bag which is arranged in an auxiliary chamber which is separated from the mixing chamber by a displaceable wall element. A cylindrical mixing body which is present in the mixing chamber is used to displace the wall element at the start of the mixing operation and thus to compress the film bag, so that the latter bursts open and releases the liquid component through a liquid passage which is present in the wall element.
One difficulty of this device consists in designing the wall element, the film bag and the capsule itself in such a way and in dimensioning these components with sufficiently low tolerances for the wall element to be held in its starting position while the capsule is being stored and transported but to be displaced sufficiently far and with such force, under the action of the mixing body, that the film bag bursts open. In this context, it should be borne in mind that the fact that the film bag is often only partially emptied leads to undesirable changes in the mixing ratio and therefore to deterioration in the properties of the finished mixture. Another drawback is that this arrangement is only suitable for mixing, but not for application of the paste.
DE 93 03 268 U1 describes a multicomponent mixer capsule with ejection device for a mixed compound, primarily for dental purposes. This mixer capsule has an activation mandrel which is located in the interior of the capsule and is anchored against the direction of ejection by means of holders in the interior of the capsule body, and a liquid compartment, which is accommodated in the interior of a ram and is sealed with respect to the activation mandrel by a destructible membrane. The activation mandrel fits flush into the empty vessel in the interior of the ram and seals the latter while the material is being forced out. While the material is being forced out in the longitudinal direction, the liquid passes through the thin capillary, which comes to lie in the interior of the activation mandrel, into the mixing space. It is explained that, even during the mixing operation in a vibration mixer and during the discharge of the compound via the ejection nozzle, a small residue of liquid, which is not precisely reproducible, always remains in the capillary. This impairs the quality of the results of mixing.
Consequently, the present invention is based on the object of providing an improved mixer capsule which avoids the abovementioned problems without impairing the desired results of mixing.
This object is achieved by a mixer capsule and a mixer unit which includes this mixer capsule as described in the claims.
The mixer capsule according to the invention has, inter alia, the following advantages:
The moveable body which is present in the mixer capsule serves not only to activate the capsule by destroying the separating device and to assist the mixing operation, but also as a displacement body during emptying.
Since, in the starting state, the body is situated in the main chamber, the activation preferably takes place automatically at the start of the mixing operation, by contrast to the activation steps known from the prior art, which have to be carried out manually.
Since, furthermore, the auxiliary chamber is separated from the main chamber by the separating device through which the body can penetrate, during the subsequent mixing operation it forms part of the mixing chamber itself. This ensures that the second component, which is contained in the auxiliary chamber, completely enters the mixture which is being formed.
Moreover, the unification of main chamber and auxiliary chamber advantageously increases the mixing volume available.
In the final phase of the discharge operation, the body assists with the virtually complete emptying of the interior of the mixer capsule which is formed by the main chamber and auxiliary chamber.
A further advantage is the small number and simple design of the components of the mixer capsule.
The moveable body is preferably of spherical design. The diameter of the ball preferably lies in the range from 4-10 mm, particularly preferably in the range from 5-8 mm.
The weight of the moveable body is adjusted to the condition of the separating device in such a manner that, during normal transport and normal handling, the separating device is not damaged by the moveable body. The separating device can only be penetrated once acceleration values of, for example, 100-500 g (1 g=9.81 ms
−2
), preferably 200-400 g, which customarily occur in capsule mixer units are reached.
The auxiliary chamber is preferably in the shape of a hemisphere with a radius which is slightly larger than that of the body. This is favorable for the mixer capsule to be emptied with the minimum possible amount of residues.
It is advantageous if the separating device adheres to an annular surface, which delimits the auxiliary chamber, of the piston and the transition between the annular surface and the inner wall of the auxiliary chamber has a sharp-edged region.
This sharp-edged region preferably runs over a part of the circumference, preferably over substantially 60°-120°, particularly preferably from 70°-90°. The transition between annular surface and the inner wall of the auxiliary chamber is preferably rounded in the remaining region. This embodiment prevents the foil from tearing off altogether.
In a particular embodiment, the separating device has a desired breaking point, which contributes to controlled and reliable opening of the auxil
Hager Gabriele
Hartung Martin
Peuker Marc
Stenger Angela
3M ESPE AG
Crowell & Moring LLP
Luong Shian
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