Anti cross-contamination dual cartridge dispenser

The present invention is directed to an apparatus for dispensing a two-part adhesive. The apparatus includes a cartridge body having two vessels for containing separate liquid components, respectively. Each vessel has a corresponding nozzle with an orifice in fluid communication with the corresponding vessel. The apparatus also has a cap frangibly connected to the nozzles to seal the orifices prior to opening the vessels. The cap is constructed so that separation from the nozzles opens the orifices. Once disconnected, the cap is removably securable to the nozzles. The cap also has a receptacle that conforms to the profile of the nozzles to prevent cross-contamination of the liquid components.

FIELD OF THE INVENTION 
The present invention generally relates to the field of dual compartment 
dispensers. In particular, the invention relates to dispensers used to mix 
two, otherwise separated, components for use. 
BACKGROUND OF THE INVENTION 
Dual compartment dispensers are available for separately containing liquid 
or flowable components that react when mixed. For example, one such 
compartment may contain an epoxy-based resin and the other compartment may 
contain a hardener. A dual plunger structure is manually compressed, 
dispensing the previously separated liquid adhesive components onto the 
work surface. The epoxy and hardener are mixed and react to form an 
adhesive that cures to form a strong bond. 
Because it is desirable for the adhesive components to react quickly, it is 
important to prevent any unused liquid from mixing and reacting. That 
problem is known in the art as "cross-contamination." Cross-contamination 
is highly undesirable because at least a portion of the liquid contents 
are lost or wasted. Moreover, if the cross-contamination is severe enough, 
most or all of the entire contents of the dispenser may be lost. To save 
any remaining uncontaminated liquid, the hardened resin plugging the 
orifices must be cut away along with the orifice structure. That procedure 
is highly undesirable because the structure may be so damaged that it 
cannot be resealed, or reused, resulting in loss of any remaining or 
unused liquid. 
Another disadvantage of prior dual compartment or cartridge dispensers is 
that the orifice structures themselves cause cross-contamination. Prior 
orifices are positioned so close together that the liquids, by design, mix 
immediately upon exiting their respective orifices. Such orifice 
structures are known in the art as "mix nozzles." Other dispensers employ 
a structure attachable to the orifice that combines the two exiting 
liquids into one stream. Such structures may facilitate mixing, however, 
the last-remaining liquid after an application is cross-contaminated. Such 
liquid will cure and harden, plugging the orifice and the associated 
channel. 
Still other prior dual dispensers employ a cap or plug structure to reseal 
and to prevent the liquid contents from drying out and plugging the 
orifice. However, such cap structures fail to prevent cross-contamination 
because the cap can be secured to the dispenser "both ways." By "both 
ways" it is meant that the cap has identical portions for each dispenser 
chamber orifice. Thus, the cap can be secured over either of the orifices 
interchangeably. Because of such interchangability, the user will 
eventually inadvertently secure the cap both ways, causing 
cross-contamination through residual material held in the cap. 
Another disadvantage of prior dual compartment dispensers is that, prior to 
the initial use, the orifices are sealed with cumbersome structures. Such 
structures include molded-in, plug-shaped seals that must be cut with a 
sharp metal object, such as a knife. Such non-frangible seals are 
cumbersome and potentially dangerous. 
Hence, there exists a long-felt need for a dual cartridge dispenser that 
overcomes the disadvantages and problems in the prior devices as discussed 
above. 
OBJECTS OF THE INVENTION 
One object of the present invention is to provide an improved dual 
cartridge dispenser that is constructed to protect against 
cross-contamination of the liquid contents. 
Another object of the present invention is to provide an improved dual 
cartridge dispenser in which a cap is replaceable on the nozzles in only 
one manner to avoid cross-contamination. 
Yet another object of the present invention is to provide an improved dual 
cartridge dispenser where the cap is frangibly connected to the nozzles to 
seal the same prior to use, and to facilitate the opening of the dispenser 
without the use of tools. 
SUMMARY OF THE INVENTION 
The above-identified objects are met or exceeded by the present apparatus 
for dispensing a two-part adhesive. The apparatus includes a cartridge 
body having two vessels each containing respective liquid components. Each 
vessel has a corresponding nozzle that defines an orifice in fluid 
communication with the corresponding vessel. 
The apparatus also includes a cap integrally formed with and frangibly 
connected to the nozzles. That connection seals the orifices prior to 
opening the vessels. The cap has an outer shell that is constructed to 
separate from the nozzles by twisting the cap, thus opening the orifices. 
The cap also has a construction which prevents cross-contamination of the 
respective liquid components. Preferably, the nozzles each have a distinct 
profile, and the cap includes two receptacles, each configured to conform 
to a respective nozzle profile so that one receptacle can only engage one 
nozzle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIGS. 1 and 2, the assembled dual cartridge dispenser of 
the present invention is generally designated 10 and includes a unitary 
cartridge body 12 having two generally cylindrical, hollow cartridges or 
vessels 14,16 and a transversely projecting body flange 18 located at a 
first end 19 of the body 12. Each vessel 14, 16 is provided with a 
corresponding liquid component, such as an epoxy resin in one vessel, and 
a hardener in the other. The cartridge body 12 also includes two nozzles 
20,22 each in fluid communication with the vessels 14, 16 (best seen in 
FIG. 2). The nozzles 20, 22 are located at a second end 23 of the body 12 
opposite the first end 19. 
A unitary plunger 24 has a pair of parallel piston shafts 26,28 and a 
flange-like plunger activating bridging portion 30 disposed at one end of 
the plunger 24. In the preferred embodiment, the piston shafts 26,28 
include support formations such as gussets 32. 
At the ends of the shafts 26, 28 opposite from the bridging portion 30, 
each shaft 26,28 has a corresponding piston head assembly 34. The piston 
head assemblies 34 are substantially identical to each other, and each 
includes a pair of sealing rings 36,38 axially spaced by a shaft segment 
40 of the corresponding shaft 26, 28. The construction and operation of 
unitary plunger 24 is provided in greater detail in commonly assigned U.S. 
Pat. No. 4,121,739 which is incorporated herein by reference. 
Referring now to FIGS. 1-3, a cap 42 is integrally formed with, and 
frangibly connected at an outer shell 43 to the ends of the nozzles 20,22. 
Each nozzle 20,22 has a curved profile 44,46 which is oblong and flattened 
when viewed from the bottom (best seen in FIG. 4) and, when viewed from 
the side with one generally straight wall portion 45 and one generally `S` 
shaped wall portion 47 (best seen in FIG. 3). The nozzles 20,22 are 
constructed and arranged on the body 12 to be mirror images of each other. 
The cap 42 is configured to be disconnected from the nozzles 20,22 by 
manually breaking the frangible seals 48,49 formed therebetween. 
Since the cartridge body 12 and the cap 42 are preferably molded as a 
single piece, it is important that the seals 48,49 are thick enough to 
permit the flow of liquid plastic through the mold to form the cap. At the 
same time, the seals 48,49 cannot be made too thick or they will lose 
their frangibility. 
The cap 42 includes two receptacles 50,52 each having a wall surface 54,56 
defining an inner shape or profile. The wall surfaces 54,56 are also 
preferably mirror images of each other. The shape or profile of the wall 
surfaces 54,56 generally correspond to the respective nozzle profiles 
44,46 as shown in FIGS. 5 and 6. The nozzle profiles 44,46 and the 
receptacle wall surface profiles 54,56 are configured to conform to each 
other so that the cap 42 is removably secured to, or engages, the nozzles 
20,22. 
The receptacles 50,52 are generally configured in a "V" shape, when viewed 
from the front of the dispenser 10 (best seen in FIG. 2). Also, the 
receptacles 50, 52 each have a generally S-shaped wall 51 corresponding to 
the curved wall portion 47 of the nozzles 20,22 and a straight wall 53 
corresponding to the wall portion 45. The receptacle wall surface profiles 
54,56 generally correspond to the nozzle profiles 44,46, which are also 
generally configured in a "V" shape (best shown in FIG. 6). 
A prong 58,60 is located in each of the receptacles 50,52 and is preferably 
integrally joined at a base 59 of the cap 42. Each prong is dimensioned to 
matingly engage a corresponding orifice 62, 64 formed by the nozzles 20, 
22 when the removal of the cap 42 breaks the seals 48, 49. It is preferred 
that the prongs 58,60 are disposed in the corresponding receptacles 50,52 
near adjacent ends to create an "offset" or "cross-eyed" appearance (best 
seen in FIG. 2). The prongs 58,60 engage and seal the orifices 62,64 when 
the cap 42 is removed and releasably secured to the nozzles 20,22. In the 
preferred embodiment, tips 66,68 of the prongs 58,60 are tapered to 
facilitate entry into the orifices 62,64. 
Referring now to FIG. 6, once the cap 42 is removably secured to the dual 
cartridge dispenser body 12, the nozzle profiles 44,46 fit and conform to 
the profile of the receptacle wall surfaces 54,56. To obtain this properly 
closed relationship, it is readily apparent that the cap 42 may only be 
removably secured to the nozzles 20,22 in the configuration shown. For 
example, the cap 42 could not be secured to nozzles 20,22 if the cap 42 
was rotated 180.degree. because the nozzle profiles 44,46 would not 
conform to the receptacle wall surface profiles 54,56. For that reason, 
cross-contamination of the liquid vessel contents is prevented. 
In operation, the dispenser 10 is provided with the cap 42 in the position 
shown in FIGS. 2 and 3. Thus, the cap forms the seals of the nozzles 20, 
22. To open the dispenser 10, the user merely twists the cap 42, which due 
to the frangible attachment at the seals 48, 49, radially breaks off, 
creating the orifices 62,64. The contents of the dispenser 10 may then be 
used by depressing the plunger 24. When closure is desired, the cap 42 
(once disconnected) is rotated 90.degree. from its position seen in FIG. 3 
and is axially manipulated so that the receptacle wall surfaces 54,56 
match the nozzle profiles 44,46 (best seen in FIGS. 5 and 6). In this 
position, the prongs 58, 60 are matingly engaged in the orifices 62,64. 
While a particular embodiment of the anti cross-contamination dual 
cartridge dispenser of the invention has been shown and described, it will 
be appreciated by those skilled in the art that changes and modifications 
may be made thereto without departing from the invention in its broader 
aspects and as set forth in the following claims.