Paint toning machine

The object of the invention is a paint toning machine comprising at least one paste container (4, 5) for keeping toning paste and means (1, 2) attached to the paste container for dispensing the paste. To avoid drying of the toning paste in the paste container the paste container is essentially gas-tight and airless and comprises an intermediate container (4) of elastic material, such as plastic, and a replaceable refill container (5) likewise of elastic material, such as plastic, the refill container being connected to the intermediate container in such a way that the interiors of the containers are in contact with each other, both parts of the paste container being compressible and the volume of the interior of the paste container essentially corresponding to the amount of paste in the container at any given time.

This invention relates to a paint toning machine comprising at least one 
paste container for keeping toning paste and means attached to the paste 
container for dispensing the paste. 
In paint toning machines toning pastes of various types are used, the 
pastes being either water-thinned or solvent-thinned. It is common to all 
colour pastes that they dry rather easily when they come into contact with 
air. Some colour pastes may even deteriorate when they come into contact 
with air. In typical paint toning machines, however, colour pastes are 
placed in containers that contain a greater or smaller amount of air 
depending on the amount of paste in the container. When solvent-thinned 
colour pastes are concerned, the air in the container is saturated fairly 
quickly with solvent fume whereby drying is essentially inhibited. The 
problem is, however, the tightness of the containers in other respects, 
since on the one hand the containers should allow fresh air to enter the 
container as paste is dispensed therefrom but on the other hand they 
should not leak solvent fumes for reasons of health and especially of fire 
protection. 
The object of the present invention is to provide a paint toning machine in 
which the above problems of the known paint toning machines have been 
eliminated. This is achieved by means of a paint toning machine according 
to the invention, which is characterized in that the paste container 
comprises a compressible container of elastic material, such as plastic. 
Particularly advantageously the paste container is essentially gas-tight 
and airless and comprises an intermediate container of elastic material, 
such as plastic, and a replaceable refill container likewise of elastic 
material, such as plastic, which is connected to the intermediate 
container in such a way that the interiors of the containers are in 
contact with each other, both parts of the paste container being 
compressible and the volume of the interior of the paste container 
essentially corresponding to the amount of paste in the container at any 
given time. By means of the compressible intermediate container that can 
be closed in an airtight manner the paste is always kept in an airless 
space and the volume of the paste container is adjusted to the amount of 
paste in the container at any given time and it is not necessary to 
introduce air into the container to replace the paste dispensed. Thereby 
drying of the paste is inhibited completely and the risk of leaking any 
solvents present in the paste is also avoided. 
Preferably a valve is fitted between the intermediate container and the 
refill container to open and close a connection therebetween especially 
when the refill container is replaced. The most practical alternative is 
that the valve comprises means for opening a connecting aperture to the 
refill container when the container is connected to the intermediate 
container. 
Thus, in the paint toning machine according to the invention part of the 
paste container can be formed by a replaceable compressible refill bag or 
refill container of elastic plastic material which is replaced with a new 
full container when empty. Preferably the refill container is placed above 
the intermediate container to make the paste transfer gravitationally from 
the refill container to the intermediate container. Thereby the emptying 
of the refill container can be simply and effectively detected with means 
which is attached to the intermediate container and detects the 
compression thereof. In this kind of arrangement the intermediate 
container does not begin to be compressed until the refill container is 
completely empty. This is a simple and effective way of detecting the 
emptying of the refill container and avoiding the risk that the paste 
container would empty completely during dispensation.

The FIGURE shows an arrangement for one colour paste of the paint toning 
machine according to the invention for both keeping of paste and 
dispensation thereof. It is to be understood that a conventional paint 
toning machine comprises a plurality of such arrangements, one for each 
colour paste needed. The arrangement shown in the FIGURE for keeping of 
paste and dispensation thereof when necessary to a vessel 13 containing 
basic paint to be toned through an aperture made on the cover thereof 
comprises a paste container formed by a refill container 5 and an 
intermediate container 4 and means attached to the intermediate container 
4 for dispensation of the paste. Both the refill container 5 and the 
intermediate container 4 are of elastic material, such as plastic, the 
strength and composition of material whereof can be selected in line with 
the requirements of the type of paste that is to be used in the machine. 
The refill container 5 is a bag-like completely closed container to which 
a connection piece 8 presented as a tubular connection hose in the 
embodiment of the FIGURE is attached. The interior of this hose in the 
solution described is in direct contact with the interior of the bag 5 and 
closed only with a film fitted at the end of the hose 8. The intermediate 
container 4 is described as a tubular elongated bag closed at the ends 
thereof by puckering. The refill container 5 is connected to the 
intermediate container 4 in such a way that the interiors of the 
containers are in contact with each other. This contact is effected 
through the above-mentioned hose connection 8 and a connector 9 at the end 
thereof to a connecting valve 6 and from there through a connector 10 to a 
hose 11, which in turn is connected through a connector 12 to the 
intermediate container 4. When the valve 6 is open, the interiors of the 
containers 4 and 5 are in direct contact with each other. The container 5 
is placed above the container 4 in such a way that the paste in the 
container 5 runs gravitationally to the container 4 as paste is dispensed 
from the container 4. Preferably the connecting valve 6 has such a 
structure that when it is moved to a position effecting contact it also 
cuts the film closing the refill bag 5, whereby the paste is free to run 
from the bag 5 to the container 4. 
Dispensation from the intermediate container 4 is effected in a fairly 
conventional manner. For this a pipe connection 15 is attached to the 
intermediate container 4 by a connector 14, the pipe connection having a 
pump 1, such as a gear-type pump, driven by a motor 7 optionally through a 
gear system. From this pump the paste transfers through a pipe connection 
16 and a valve 2 operated both manually and with a magnet coil 3 either 
through a pipe connection 19 to a vessel 13 containing basic paint to be 
toned or through a pipe connection 17 and a connector 18 back to the 
intermediate container 4. Thus the paste can be recirculated through the 
connection 17 to the intermediate container to keep it suitably viscous. 
In the solution shown in the FIGURE four shafts 22 eccentrically mounted in 
bearings are fitted below the intermediate container 4 in connection 
therewith, and by twisting the shafts the paste in the intermediate 
container 4 can be stirred to keep it homogenous. Further, the container 4 
is connected with a detecting element, such a microswitch 21 provided with 
a detecting spring 20, which detects the compression of the intermediate 
container. The compression begins when the refill container 5 has emptied 
and no more paste runs therefrom to the intermediate container and 
dispensation from the intermediate container 4 begins. Thus, with the 
detecting element 21 it is possible in a very simple and effective way to 
observe the compression of the intermediate container when it begins to 
empty and above all to receive information about the emptying of the 
refill container and thereby replace it with a new refill container in 
good time before the risk arises that even the intermediate container 
might become empty. When the refill container 5 is replaced the valve 6 is 
naturally closed, whereby air cannot enter the intermediate container 4. 
Since the refill container 5 is also quite full and consequently airless 
when it is connected with the valve 6, the whole paste container, which is 
formed by the refill container 5 and the intermediate container 4, is kept 
completely airless in all steps of operation of the paint toning machine 
according to the invention. 
The paint toning machine according to the invention has been described 
above only by way of example by means of one structural solution and it is 
to be understood that the idea according to the invention concerning a 
compressible paste container could be applied in many other ways than in 
the way illustrated by the FIGURE. In the simplest embodiment the paste 
container can be formed by only one compressible container, which can be 
either fixed to the machine whereby a valve through which the container 
can be filled and by which it can be closed in an airtight manner is 
attached thereto, or be separate from the machine whereby it is formed by 
a replaceable bag essentially corresponding to the refill container 5. 
When the container is a fixed container the filling can be carried out 
either by pouring from a pot or by attaching such a refill pot to the 
valve for as long as it takes from the paste to run from the pot into the 
container. Naturally, the volume of the vessel from which the container is 
filled can be so great as to suffice for more than one refill of the 
container. One alternative structural solution is an application in which 
the dispensing pump is placed within the container 4. Thereby the valve 
conducting the paste to the circulation conduit or alternatively to 
dispensation could be placed within the container like the circulation 
conduit itself, whereby the container 4 would form a whole optionally 
comprising two bags at least partly within each other.