GB2126654A - Device for dispensing viscous materials - Google Patents

Abstract

The device is provided with a container (6) for material such as printing ink or glue in the lower part of which there is a pipe (9) through which the material is supplied to a housing (10) occupied by a horizontal axis, conical endless screw (11), perpendicular to the axis of the container (6), the housing (10) being provided with a horizontal outlet pipe (12) for feeding the material to a nozzle (2). Variable, intermittent rotatory movement is given to the conical endless screw (11) through a cam (17) and a rocker arm (15), the latter being keyed, via a free wheel coupling, to a shaft integral with the conical endless screw (11). Regulation of the quantity of material supplied to rollers (3) may be effected by manual adjustment of a screw 20 or automatically by an optical device (21) and a servo motor (22). <IMAGE>

Description

SPECIFICATION Device for dispensing viscous materials The invention relates to a device for dispensing viscous materials such as, for example, glue, printing ink and similar, that have to be supplied in determinate quantities on to surfaces, spreader rollers in particular, in thin film form.

More specifically, the invention relates to devices for dispensing ink to printing groups employed for placing decorative borders and/or repetitive wording or wrapping and tissue paper etcetera, wherein for this purpose use is made of inks that are so concentrated as to be pasty.

A device of the aforementioned type is known (described in U.S. Patent No. 3 345 943), in which printing ink is placed in the inside of a cylindrical container provided with an expulsion nozzle.

The ejection of the ink from the nozzle is achieved through a piston assembled hermetically inside the container and able to slide intermittently therein.

With a device of this particular type it is not possible to obtain, even when one is able to set in amplitude the strokes of the piston, a fast,, accurate response to control instructions for varying or suspending the outgoing flow of ink.

The reason for this can be attributed both to the interposition between the piston and the nozzle of the entire mass of ink in the inside of the container, and to the elastic deformation potential of the container.

Variations in the viscosity of the ink consequential to the prolonged period of time the ink has been inside the container, or to changes in the ambient conditions, contribute to worsening the said problem.

The object of the invention is to make available a device for dispensing viscous materials that is provided with means for regulating the outgoing flow with extreme rapidity and precision, with everything being done through a solution which, in relation to the results achieved, is both simple and functional.

This and other objects too are all attained by the device according to the invention for dispensing viscous materials, of the type comprising: a containerforthe said material, an expulsion nozzle, a connecting pipe between the said container and the said nozzle, and thrust means for forcing the said viscous material towards the said nozzle, constituted by a conical endless screw rotatable inside a corresponding housing, the latter provided with an outlet pipe that forms part of the said connecting pipe and ends at the said nozzle, the said endless screw being dependent on control means designed to cause it to undergo a variable intermittent rotatory movement.

Further characteristics and advantages of the device according to the invention will become more apparent from the description that follows of one embodiment, shown purely as an unlimited example on the accompanying drawings, in which: Figure 1 shows, diagrammatically, in a lateral view, the device forming the subject of the invention, with certain parts in sectional form; Figure 2 shows, diagrammatically, the device depicted in Figure 1 along the line Il-Il.

With reference to the above listed figures, shown globally at 1 there is a device for dispensing viscous materials, suited in particular to be utilized as an inking device for supplying, through a nozzle 2, pasty state concentrated ink to the inking rollers 3 of a printing group 4.

The ink is stored inside a cartridge 5 placed in a container 6 that comprises a lower body 7 and an upper cover 8.

In the said body 7, a vertical pipe 9 places an outlet aperture in the said cartridge 5 in communication with a housing 10 containing thrust means constituted by a horizontal axis conical endless screw 11.

The housing 10 is provided with an outlet pipe 12, this too horizontal, perpendicular to the axis of the said housing 1 0 and ending at the said expulsion nozzle 2.

A shaft 13, integral with the endless screw 11 and coaxial thereto, projects externally from the lower body 7, and to this is connected, through a free wheel coupling constituted by a non-return roller 14, a rocker arm 1 5. The latter is provided in the centre with a roller 1 6 that is designed to cooperate with a cam 1 7 fixedly mounted on a shaft 18, carried in continuous rotation connected to the means that drive the machine on which the device in question is being utilized.

Contact between the roller 1 6 and the cam 1 7 is, in this way, fostered by a spring or elastic means 19 exerting an effect on one extremity of the rocker arm 15, while in another way, it is obstructed by an abutment element constituted by an adjustable screw 20, which also exerts an effect on the said extremity of the rocket arm 1 5.

The operation of the device is as follows. When coming into contact with the roller 16, the cam 1 7 that is given continuous rotatory motion causes the rocker art 1 5 to undergo continuous oscillatory movement and this in turn, by virtue of the non return roller 14, determines an intermittent rotation of the shaft 1 3 and, therefore, of the conical endless screw 11.

The extent of the said rotation can be set by the screw 20 on which the amplitude of the angle of contact between the roller 16 and the cam 1 7 is dependent.

By adjusting suitably the oscillation of the rocker arm 15, it is possible to regulate the flow, that is to say, the quantity of material supplied to the inking rollers 3. The operator can be entrusted with effecting the said regulation after a visual check has been made on the characteristics of the print, or alternatively the regulation can be automatic, for example by means of an optical type element 21 connected to a servomotor group 22 that moves directly the adjusting screw 20.

In case of need, in order to increase the regulation potential of the entire device, instead of being connected to control means provided with continuous rotatory motion, the shaft 1 3 can be connected to control means provided with variable rotatory motion.

To conclude, at 23 has been shown a hole, made in the cover 8, which is connected to the outside atmosphere or to a non-illustrated source of compressed air.

Differently from what has been stated à propos of the known art, the ink thrusting element (namely the conical endless screw 11) is placed in the inside of a housing that is not subjected to elastic deformation, in the immediate vicinity of the expulsion nozzle.

This enables the regulation of the outgoing flow to be fast and accurate; furthermore, it makes the blocking possible, in an almost instantaneous fashion, of the delivery of the oil in, for example, the event of the machine coming to a halt.

Note should also be taken of the fact that the material contained in an extremely reduced quantity in the housing 10 and kept agitated by the endless screw, is liable to undergo only very limited variations in the viscosity thereof.

The embodiments of the device according to the invention can differ in form from what has been outlined above and, in particular, numerous modifications of a practical nature may be made without, because of this, there being any deviation from the framework of protection afforded to the invention.

Claims (6)

Claims

1. A device for dispensing viscous materials, the device comprising a container for the viscous material, an expulsion nozzle, a connecting pipe between the container and the nozzle, and thrust means for forcing the viscous material towards the said nozzle and constituted by a conical endless screw rotatable inside a housing, the latter being provided with an outlet pipe that forms part of the connecting pipe and terminates at the nozzle, the endless screw being dependent on control means adapted to cause it to undergo a variable intermittent rotational movement.

2. A device according to claim 1, wherein the control means are constituted by a rocker arm connected, through a free wheel coupling, to a shaft integral with the conical endless screw, and provided in the centre with a roller adapted to cooperate with a cam fixedly mounted on a continuously rotatable shaft and connected to a source of motion, elastic means being provided that exert a force on the rocker arm to urge it into contact with the cam, and there being an adjustable abutment element that also acts on the rocker arm to define the relative positions of the cam and the roller.

3. A device according to claim 2, comprising servomotor means for moving the abutment element, the input of the servomotor means being connected to an element for verifying the characteristics of the print when the device is applied to printing apparatus.

4. A device according to any one of claims 1 to 3, wherein the conical endless screw has an axial extension substantially perpendicular to the axis of the container.

5. A device according to any one of claims 1 to 3, wherein the conical endless screw has an axial extension substantially perpendicular to the axis of the nozzle.

6. A device for dispensing viscous materials, substantially as hereinbefore described with reference to the accompanying drawings.