Process of and apparatus for shaping extrudable material
BACKGROUND OF THE INVENTION 
     The invention relates to a shaping device for extrudable material, for example for manufacturing food products, and in particular for ice confections, the shaping device comprising at least one extrusion nozzle and a movable support surface arranged at some distance from the nozzle for directly receiving extruded product therefrom, each nozzle having feeding means for extrudable material, all nozzles being arranged on a common carrier, which is at least rotatable with respect to the support surface about an axis of rotation which is not an axis of complete rotational symmetry of all nozzles, and motor means for effecting the relative movement of the carrier and the support surface. 
     DESCRIPTION OF THE PRIOR ART 
     An apparatus of this general kind is described and shown in EP 44,689, allowing the manufacture of twisted products. However, there is continuing need of more varied products, either as regards pattern, or ornament, or configuration, or shape, or texture or any combination thereof. 
     It is the aim of the present invention to provide a method and apparatus for easily manufacturing such varied and complex products. 
     SUMMARY OF THE INVENTION 
     According to the invention, this may be realized by using a shaping device of the general kind as described above, the motor means of which are adapted for both relative rotational and translational movement in at least one direction of the carrier and the support surface, the actuation of these motor means being controlled by a programmable computer. 
     For even more freedom of shape and flexibility of manufacture, the carrier may be mounted in a frame which is movable along guides in at least two orthogonal directions. 
     For manufacturing products having a height of several centimeters, it is to be preferred that the carrier be movable up and down with respect to the support surface. 
     Even more variegation can be accomplished if the nozzles each are provided with valve means, the action of which is controlled by the same computer as the motor means, which valve means are arranged at a small distance from the actual nozzle opening so that, in use, no material will be leaking out of the nozzle opening after closing the valve means. Usually, this distance will not be in excess of 5 cm, and more preferably not in excess of 3 cm. As a result, a reliable action is obtained, resulting in shapes of proper definition. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Some characteristic examples of devices according to the invention are given below and shown in the accompanying drawings, in which: 
     FIG. 1 is a schematic representation of a first embodiment of a device according to the invention. 
     FIG. 2 is a schematic representation of a second embodiment of a device according to the invention. 
     FIG. 3 is a partial sectional view of a nozzle for use in a device according to the invention. 
     FIG. 4 is a partial perspective view of a third embodiment according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawing, FIG. 1 shows a belt conveyor 1, forming a supporting surface for directly receiving extruded products from an extrusion device 2 arranged above this conveyor. The extrusion device comprises two nozzles 3,4, which are arranged in a common carrier 5 and which each have separate supply means 6,7, through which extrudable materials may be fed to the nozzles. 
     The carrier 5 is attached to, and supported by, a central shaft 8 which may be driven for rotation by a stepper motor 9. The actuation, i.e. rotational direction, speed, acceleration, can be controlled at will by a programmable computer 10. Usually, a stepper motor driver unit 11 is arranged between the computer 10 and the motor 9. 
     The device shown in FIG. 2 also comprises a belt conveyor 12, along which guides 13, 14, 15 are arranged in three orthogonal directions. These guides are slidable with respect to each other. Inside the guides, stepper motors (not shown) are accommodated which, by suitable transmission means such as a chain or a worm transmission, may effect a mutual movement of the guides as indicated by the double arrows. 
     The guide 15 supports a carriage 16, which is slidably arranged on said guide and which supports an extrusion gear. On top of the carriage, a stepper motor 17 is supported, the shaft 18 of which is rotatably supported in the carriage 16. The lower end of the shaft 18 supports a disc-shaped carrier 19, to which, at regular angular distances, extrusion nozzles 20, 21, 22 are attached. The nozzles may be supplied with extrudable material through flexible hoses 23. The flow of material through the nozzles can be controlled by an internal valve, better shown in FIG. 3. 
     In FIG. 3 a longitudinal section through a nozzle 20 is shown. This nozzle comprises a body 24 supported on the carrier 19. The flexible supply hose 23 is attached to a lateral stud 25, through which material is supplied into the body 24. Inside the body, a valve body 26 can be reciprocated towards and from a valve seat 31 by a motor means 27, such as a pneumatic actuator, which is connected to the valve stem 28. The valve is shown in the open position; the closed position is shown, using interrupted lines. 
     The motor means 27 of the valves 26, the stepper motor 17 of the carrier 19 and the stepper motors arranged in the guides are connected in a working relationship to a programmable computing means 29. For synchronisation with the conveyor 12, the driving means 30 of said conveyor may be connected to the computing means too. 
     The term &#34;complete rotational symmetry&#34; in this specification and claims is meant to refer to a figure having rotational symmetry, resulting in a figure of the same shape after rotation by any angle about its axis of symmetry. 
     The words &#34;move&#34; and &#34;movement&#34; are used in their broadest sense, comprising translation, rotation, vibration, swivel, pivor movement and any combination. 
     Although stepper motors are preferably used in the devices according to the invention because of their easy control by electronic or computing means, it should be noted that any well-controllable motor can be used for this purpose. 
     The embodiment, as partially shown in FIG. 4, comprises a round support plate 32, which is rotatably mounted on,  and drivable by, a motor 33. On the support plate 32, which is driven in the direction as indicated by the arrow 34, extrudable material 35, extruded through three extrusion nozzles 36, is received. By suitably controlling the extrusion velocity and the rotational speed of the support plate 32, differently shaped products can be made. During the extrusion and shaping process, the nozzles 36, which are attached to a common central supply pipe 37 forming a carrier, are gradually moved upwards by actuating a motor 38 which, through a rack and a pinion drive, can move the supply pipe 37 through a fixed bearing block 39 as indicated by a double arrow 40. A flexible hose 41 connects the supply pipe 37 to a supply of extrudable material. Both motor 33 and motor 38 are connected to a common programmable computer 42. If desired, this computer can be used for controlling any valves in the nozzles 36. 
     The invention also relates to a process of shaping extrudable material, an exemplary embodiment being shown in FIG. 2, by extruding said material through at least one extrusion nozzle 20,21,22, which is arranged with its nozzle opening at some distance from a movable support surface 12 for directly receiving the material extruded therethrough, driving each nozzle for rotation about a common axis which is not an axis of complete rotational symmetry of all nozzles and for translation in at least one direction, the rotation and translation being relatively to the support surface, wherein the rotation and the translation are controlled by a common computer. 
     According to a preferred embodiment, resulting in shapes of more proper definition, the computer means are also adapted to control valve means arranged at a small distance of particularly not more than 5 and preferably less than 3 cm from the opening of each nozzle, so that, in use, no material will be leaking out of said opening after closing the respective valve.