Dispensing – With cutter and/or punch – To form dispensing opening in container
Reexamination Certificate
2001-04-16
2002-03-05
Derakshani, Philippe (Department: 3754)
Dispensing
With cutter and/or punch
To form dispensing opening in container
C222S137000
Reexamination Certificate
active
06352177
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for discharging a pasty two-component mixture, e.g. a mixture of a dental impression substance and a catalyst for initiating or accelerating the hardening.
SUMMARY OF THE INVENTION
For applying multi-component substances in mixed form, discharge devices are known which comprise a supply container with at least two chambers for respectively one of the pasty components of the mixture. Assigned to each chamber is an outlet stub for discharging the pasty substance upon application of pressure. To allow discharge of the pasty substances in mixed form, the outlet stubs of the known devices have a mixer unit mounted thereon, comprising a mixer housing including a substantially tubular portion and a coupling end for attachment to a supply container. In the tubular portion of the mixer housing, a mixer element is arranged by which the components, which have been supplied via separate channels, are subjected to a turbulence and mixing effect. Said channels are formed in the coupling end of the mixer housing and extend from the inlet stub of the coupling end to the mixer element. A device of this type is known e.g. from EP-A-0 730 913.
Depending on the composition of the pasty components, their mixing will result in the respectively desired chemical reactions. For instance, if one of the two pasty components is a dental impression substance, the adding of a second component initiates and accelerates the polymerisation of this impression substance. Should this second component (also referred to as a catalyst) penetrate, via the mixer unit, from the one chamber into the other chamber of the supply container or should already the outlet stub of the chamber for the dental impression substance by contaminated with the catalyst, the whole device will be rendered useless, which, depending on the extent to which the chambers are filled, will cause a considerable loss of expensive material. Therefore, the two component flows have to remain separated from each other for the longest possible stretch of their moving paths and be brought together only within the tubular portion of the mixer housing.
In the known discharge device for pasty two-component mixtures, the mixer housing is detachably locked to the supply container by means of a holding shell. The holding shell is supported for rotation on the mixer housing and is provided with radially outward locking projections formed in the manner of bayonet locks, which can be rotated to move under corresponding grip-over projections of the supply container.
The invention further relates to a device for opening a tube bag containing a pasty substance. Said device is further provided to guide the pasty substance out of the tube bag.
The pasty substances are offered in rigid containers or cartridges with displaceable bottom walls which are advanced by plunger elements arranged to be advanced by hand or by means of an engine in order to exert pressure on the pasty substances, thus discharging the substances from the cartridges and the cartridges or containers. In recent years, for reducing the packing material, the pasty substances have been increasingly offered in tube bags. For discharging the pasty substances, the tube bags have to be opened, preferably on their end sides. This is preferably performed by means of stationary piercing mandrels or the like cutting elements arranged on the end wall of a holding cap surrounding the end side of the tube bag and comprising a discharge stub. From EP-A-0 787 655, it is known to provide the inner projection of the holding cap with a piercing tube resiliently biased in the direction of the end face of the end of the tube bag. The as of yet known systems for automatic opening of tube bags are in need of improvement in so far as, for opening the tube bag, it is always required to exert pressure onto the tube bag and thus also on the pasty substance in the tube bag. Thus, the process of opening the tube bag is accompanied by the discharge of the pasty substance.
As already mentioned above, discharge devices are used intermittently, the period between two successive uses being possibly so long that the mixture in the mixer unit will harden. As a result, the mixer unit has to be removed and replaced by a new one before the discharge of a mixed substance can be continued. Thus, the mixer unit is a disposable component, making it desirable to keep the number of components of this disposable mixer unit as low as possible.
It is an object of the invention to provide a device for the discharge of a pasty two-component mixture, comprising a mixer unit with a reduced number of parts.
According to the invention, to achieve the above object, there is proposed a device for the discharge of a pasty two-component mixture comprising:
a supply container with two chambers for respectively one pasty component of the mixture, the supply container being provided with a respective outlet stub for each chamber,
a mixer unit comprising a tubular mixer housing with a mixer element arranged therein, the mixer housing comprising a coupling end to be coupled to the supply container and having a two inlet stubs and two channels for the pasty components of the mixture leading to the mixer element, and comprising, on its opposite end, an outlet opening for the mixture, the inlet stubs being adapted for insertion into the outlet stubs or vice versa, and
a holding shell for the coupling end of the mixer housing arranged for rotation on the supply container, the holding shell surrounding the two outlet stubs and comprising a recess of a shape at least in parts substantially identical with the cross sectional shape of the coupling end of the mixer housing, the holding shell being rotatable between a receiving rotational position in which the recess is oriented corresponding to the orientation of the coupling end of the mixer housing in the state where the inlet stubs are connected to the outlet stubs of the supply container, and
a locking rotational position in which at least a part of the recess edge of the holding shell is in engagement over parts of the coupling end of the mixer housing.
In the inventive discharge device, the holding shell holding the mixer unit is arranged not on the mixer housing but on the supply container. On this supply container, the holding shell is supported for rotation about its longitudinal axis. The holding shell surrounds the two outlet stubs of the supply container and is provided, on its front end facing away from the supply container, with a recess which in the first rotational position of the holding shell (receiving rotational position) allows the mixer housing to be mounted onto the outlet stubs of the supply container, while, in a second rotational position (locking rotational position) the edge of the holding shell delimiting the recess has been moved over partial regions of the coupling end, e.g. over radially projecting flange portions of the coupling end of the mixer housing, thus locking the mixer housing to the supply container. Therefore, the holding shell is not a component of the mixer unit anymore and thus will be preserved for the whole period during which the discharge device is used for application of the two-component mixture.
In an advantageous embodiment of the invention, the coupling end is provided with two diametrically opposite and radially extending projections, while the holding shell is formed with a recess of a shape identical with the cross sectional shape of the coupling end at the level of the projections of the latter. Particularly, the coupling end of the mixer housing is of a substantially oval shape in the region of the radial projections. The recess of the holding shell, when in its receiving rotational position, is arranged relative to the outlet stubs of the supply container in the same manner as the inlet stubs of the mixer housing relative to the outer projections. Thus, the coupling end of the mixer housing can be moved through the recess of the holding shell until the inlet stubs of the mixer housing have been r
Bublewitz Alexander
Suchan Matthias
Derakshani Philippe
Diller Ramik & Wight
Kettenbach GmbH & Co. KG
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