Abstract:
A dispensing and dosing machine for dyestuffs includes pins having the same diameter as ducts wherein which the pins are located, the pins acting to both dispenses dyestuffs and clean the walls of the ducts.

Description:
BACKGROUND OF THE INVENTION 
     This invention proposes a dispensing and dosing machine for dyestuffs, paints and the like, equipped with a central unit for simultaneous dispensing of one or more dyestuffs or viscous liquids and a nozzle cleaning system composed of a multiple number of axially sliding pins, moved by a stepwise motor and inserted into the dispensing nozzles from above so as to ensure a complete discharge of the dyestuff and form a seal preventing the liquid in the channels from drying out. 
     DESCRIPTION OF THE RELATED ART 
     A number of devices for dispensing and dosing dyestuffs are known, which comprise a multiple number of tanks holding a different dyestuff base each, and dispensing devices capable of dispensing a predetermined quantity of dyestuff. Some electronic systems control these dispensing devices so that each of them supplies the quantity of dyestuff needed to achieve the require tinting after being mixed. 
     Modern dyestuffs are prepared by mixing a certain quantity of dyestuff base such as for instance white or gray with a small percentage of one or more dyestuffs, in a combination designed to achieve the final tinting required. 
     These dyestuffs are employed in extremely limited quantities, often just a few drops, which means that a plugging in one or more of the dispensing channels affects the quantity of the discharged material and therefore the final tinting of the product. 
     Some dosing machines are already known, such as for instance those described in the U.S. Pat. Nos. 4,314,653 and 5,042,699 by the same Applicant. 
     The patent application of the Italian utility model no. MI96U 0105 describes a dyestuff dispensing machine comprising a multiple number of dyestuff tanks arranged in a radial pattern around a central dispensing head equipped on its lateral wall with a multiple number of radial fittings for connecting to as many supply tanks, and on the bottom wall a discharge outlet connected to said fittings by passages provided inside the head. 
     The U.S. Pat. No. 5,449,028 describes a dyestuff dispensing device of a type comprising a multiple number of dispensing channels, each connected to a tank and arranged so as to discharge the dyestuff through some nozzles set in the lower wall, which provides for a removable lid for the sealing of said lower wall, shaped in a way to form a tightly sealed chamber surrounding the area for discharging the channels. 
     This sealing lid has been provided to limit the nozzles&#39; contact with air, in an attempt to prevent or at least retard the drying out of the product left over in the discharge channels. 
     The dyestuff pastes of a water base or other kind in fact have an extremely limited drying time which is a considerable source of drawbacks, as some plugs of dried-out liquid form inside the dispensing channels and to affect the dispensing process. 
     This makes it necessary to ensure a rigorous cleanliness of the dispensing channels. 
     The known systems described above, in particular that of the U.S. Pat. No. 5,449,028 have been developed precisely in the attempt of limiting this drying-out phenomenon. 
     Despite the fact that appreciable results have been achieved, the problem is still not entirely solved, as even with the use of a sealing lid the dyestuff is still left behind in the channels, and if the machine is left standing for a certain period of time, dries out and re-proposes the problem. 
     SUMMARY OF THE INVENTION 
     A solution of this problem is now offered by this invention, which proposes a dispensing and dosing machine of a type comprising a multiple number of tanks directing the dyestuff toward a central dispensing head equipped with dispensing channels, a machine fitted with a number of pins coaxial with the terminal portion of the discharge channels and having the same diameter of the latter, which are inserted into these channels from the top so as to evacuate them completely and simultaneously achieve a tight seal. 
     This solution thus allows on one hand a complete discharge of the dyestuff without risking their partial entrapment in the channels, and on the other hand prevents the drying out of the material, due to the fact that these pins achieve a perfect seal on the entire surface of the dispensing channels. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This innovation will now be described in detail, for exemplifying but not limiting purposes, with reference to the enclosed figures in which: 
     FIG. 1 describes the machine of the invention in a simplified overall form, 
     FIG. 2 is a simplified assembled view of the tanks and of the dispensing units, 
     FIG. 3 is a cross-section of the dispensing unit equipped with the cleaning system according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the FIGS. 1 and 2, the number  1  indicates the foundation of a machine mounting a multiple number of radially arranged units  2 , each comprising a tank  3  for the dyestuff, a dosing pump  4  and a dispensing complex  5 . 
     A platelet  6  is set above the dispensing and dosing units, attached to a multiple number of stems  7  respectively connected to blades designed to remove the dyestuff from the tanks which aspirate a certain amount of dyestuff from these tanks and direct it toward the dispensing devices  8 . 
     The latter are connected to a central discharging head, indicated in its overall form by the number  9  and illustrated in a vertical cross-section in FIG.  3 . 
     The number  10  indicates the body of the dispensing head, which exhibits a number of joints  11  for connecting to the dispensing devices on its lateral sides, and on the lower wall  12  of a discharge outlet  13 , a series of discharge channels connected to said joints  11 . 
     The dispensing devices pick up the dyestuff from the tanks and pump it to the joints  11 , which discharge it through the channels  14  so a to drop it into an underlying vessel. 
     The number  15  indicates the structure of the machine mounting the dispensing head. 
     A characteristic of the innovation is to provide a series of pin-type elements  11 , one for each dispensing channel  14 , attached to a disc  17  set on top of the dispensing head and actuated by a step-wise motor  18  so as to move in an alternating motion in an essentially vertical direction. 
     The pins  16  have the same diameter of the channels  14  and are coaxial with the same. 
     The shaft  20  of the motor  18  is threaded and engages with a bushing  21  which is firmly attached to the pin supporting disc  17 . 
     The run of the pin supporting disc  17  is such as to take the latter from a raised position shown on the left side of FIG. 3, in which the pins release the dispensing channels  14  thus allowing them to communicate with the joints  11 , to a lowered position shown on the right side of the same FIG. 3, in which the pins fit entirely into the channels  14 , up to the point of reaching the lower wall  12  of the discharge outlet  13 . 
     This descending motion of the pins leads to fully expelling the dyestuff and to simultaneously cleaning up the walls of the channels. 
     The pins&#39; terminal portion will preferably be pointed so as to favor the detachment of even minimal quantities of dyestuff. 
     Moreover, each pin will preferably provide some annular gaskets  25 , for instance of a lip-type, capable of ensuring a good seal and performing the function of perfectly cleaning the surface of the pin, whenever the latter is raised. 
     The operation is as follows. 
     When the product is to be dosed, the operator sets the quantity and type of the required dyestuff, by acting on certain electronic control devices of the machine. The control determines the quantity of each dyestuff to be dispensed, and actuates is the motor  18  to command the lifting of the disc  17  up to the point of moving the pins  16  above the passage connecting the channel  14  with the joints  11  (FIG. 3 to the left). 
     At this point the dosing devices dispense the required quantity of each dyestuff according to a known technology, by discharging it from the outlet  13  through the channels  14 . 
     Once the dosage has been completed, the control switches the motor  18  with the pins  16  to a reverse rotating motion, so that each of the pins penetrates into its respective channel  14 . 
     During this motion the pins, whose diameter is exactly the same as the internal diameter of the channels, totally expel the residual dyestuff and clean up the walls. 
     Once the disc  17  with the pins  16  has terminated its descent, all channels remain perfectly closed and sealed, without affording the dyestuff any chance to come in contact with the air and thus to dry up. 
     This has produced a device for the simultaneous dispensing of dyestuffs, equipped with a central self-cleaning dispenser capable of avoiding all drawbacks due to the drying-out of the material in the dispensing channels, typical of the known art. An expert in the trade may further provide for various executions of the same concept, all of which are however to be held as falling within the scope of this invention.