Description Technical field The present invention relates to a packaging machine for loose products having an elongated shape, such as, in particular, long pasta, e. g., spaghetti and the like.

More specifically, the invention relates to a packaging machine for the production of packages of loose products with a weldable plastic film, the said packaging machine comprising in combination: zea duct for introduction of the loose product ; 'along the duct, a section for loading of the loose product; 'downstream of the loading section, a section for forming the package; and a pusher to push successive batches of loose product from the loading section towards the section for forming the package.

State of the art A packaging machine of the above mentioned type is described, for example, in EP-A-0 860 359. In this known machine, the pusher comprises a plunger which moves along the duct with a reciprocating motion and is rigidly connected to a rod of length greater than the overall length of the duct itself.

The movement is conferred on the plunger and on the rod by a chain run over pulleys, one of which is motor-driven, and to which is connected the end of the rod opposite to the one with which the plunger is rendered integral. Since the duct along which the loose product is fed is of considerable length, there being set along it (in addition to the loading station) also a forming collar which winds the film around the duct, as well as longitudinal sealing means for sealing the edges of the film longitudinally, the overall length of the machine reaches large dimensions, with consequent problems for its location in production environments.

Objects and summary of the invention The purpose of the present invention is to provide a packaging machine of the above mentioned type which is not affected by the aforesaid drawbacks

and which, in particular, can be built having smaller overall dimensions.

The above and further objects and advantages, which will emerge . t N clearly for persons skilled in the art from the ensuing text, are achieved, according to the invention, by envisaging that the pusher comprises a mobile slider that moves along the duct through which the loose material is fed, said slider being constrained to a semi-flexible member, which is in turn connected to a rotating actuator provided with reciprocating rotary motion, so that the semi-flexible member is wound and unwound by means of the rotating actuator, causing the slider to perform a travel of great length, notwithstanding the limited overall dimensions of the rotating actuator.

According to a particularly advantageous embodiment of the invention, the semi-flexible member is connected by a first end to the mobile slider and by the other end to the periphery of a rotating member that forms part of the rotating actuator, on which the semi-flexible member is alternately wound and unwound to impress on the mobile slider the reciprocating translational motion inside the duct.

It is, for instance, possible to make the semi-flexible member in the form of a chain which can bend in one direction but not in the opposite direction, for example by the application of appropriately shaped plates, as will be clarified in what follows with reference to a practical example of embodiment. When the semi-flexible member consists of a chain, the rotating member can conveniently consist of a crown wheel for chains.

The slider may be represented by a simple cylindrical member, or a member having another shape corresponding to the cross section of the duct in which it has to slide. Preferably, however, according to an advantageous embodiment of the invention, the slider has a disk-shaped element forming the surface of thrust for pushing the loose product, the cross section of said disk-shaped element substantially corresponding to the cross section of the duct. The disk-shaped element is connected in a preferably rigid way to a guide element that can slide along the internal surface of the duct.

The effect of this arrangement is to confer on the slider a better guide.

The ensemble formed by the disk-shaped element and the guide element may

be advantageously rendered replaceable, with the provision of sliders of different diameters for the various transverse dimensions of the loose product - to be handled. When the transverse dimensions of the package changes, the duct is replaced by another duct of different cross section, and consequently also the slider is replaced. Instead, adjustment of the machine to different longitudinal dimensions of the product is obtained by a suitable setting of the parameters of the control program for modifying the travel of the slider.

The slider can be equipped with a guide rod arranged between the disk- shaped element that moves inside the duct and the corresponding end of the semi-flexible member.

Advantageously, to improve the guide of the pusher it is possible to provide, at the mouth of the duct, a rectilinear guide for the semi-flexible member and possibly for the rectilinear guide rod with which the slider is equipped.

Further advantageous characteristics and embodiments of the packaging machine according to the invention are set forth in the attached claims.

The invention also relates more in general to a pusher for pushing successive batches of a product along a feed duct, which comprises in combination: a mobile slider provided with reciprocating motion which moves along the feed duct ; a semi-flexible member constrained at one end to said slider and at the opposite end to a rotating actuator provided with reciprocating rotary motion.

Further advantageous characteristics of the pusher according to the invention are described in the attached dependent claims.

Brief description of the drawings A better understanding of the invention will be obtained by following the description and the attached drawings illustrating a practical, non-limiting, embodiment of the invention. More in particular, in the drawings: Fig. 1 is an overall side view of the machine;

Fig. 2 is an enlarged side view of the rotating actuator, the semi-flexible member, and the slider ; Fig. 3 is a section according to the plane indicated by III-III in Fig. 2; Fig. 4 is an enlarged side view of a length of the semi-flexible member; Fig. 5 is an enlarged side view of the loading section for loading of the loose product; and Figs. 6A and 6B are cross sections according to the plane indicated by VI-VI in Fig. 5 in two distinct configurations of the loading section.

Detailed description of a preferred embodiment According to what is illustrated in the example of the attached drawings, the machine comprises a duct designated as a whole by 1, along which there is provided a section for loading the loose product, designated as a whole by 3 and described in greater detail in what follows. Downstream of the loading section 3, located outside the duct 1, is arranged a forming collar 5 which (in a way known per se) folds a plastic film F, coming from a reel B, to form a tube wound on the outside of the duct 1, which is then sealed by a longitudinal sealing machine 7 and transversely sealed and cut in a section for forming the package, designated as a whole by 9. This forming section can be made in various ways, according to the known art of the field. An example of embodiment is illustrated in EP-A-0860359, to which reference is made for further details.

A slider, designated as a whole by 11, translates with reciprocating motion inside the duct 1, the movement of said slider being indicated by the double-headed arrow f11. The slider 11 has a disk-shaped element 15, which is rigidly constrained to a guide element 17. The disk-shaped element 15 has a cross section substantially corresponding to the cross section of the duct 1.

The guide element 17 has a disk-shaped cross section (in the example illustrated) to slide along the internal surface of the duct 1, but could also be of a different shape provided that it is such as to provide a guide for sliding along the internal surface of the duct 1 The slider 11 is hinged, in 19, to a bar 21 that is able to slide in a pair of horizontal guides 23 and 24 set upstream (with respect to the direction of feed

of the loose product) of the mouth of the duct 1 and hence upstream of the loading section 3. The bar 21 is constrained, at the end opposite to the point 19 of constraint to the slider 11, to a first free end of a semi-flexible member 25, the opposite end of which, designated by 25A, is constrained to a rotating actuator 27.

In practice, as shown in the example illustrated, the semi-flexible member consists of a chain, the links 29 of which are constrained together by shaped plates 31. The rotating actuator 27 accordingly consists of a chain wheel and is driven in rotation in alternate directions by a motor 33 and a belt 35.

As may be seen in particular in Fig. 4, each plate 31 has, at a first end, a surface 31A, which is approximately parallel to the plane that joins the axes 29A in which the links 29 of the chain are hinged, and substantially orthogonal to two plane side surfaces 31 B and 31 C. The opposite end of the plate 31 has a first surface 31 D, which is substantially parallel to the surfaces 31 B and 31 C, a second surface 31 E, which is inclined with respect to the plane joining the axes 29A, and a further surface 31 F, which is also inclined.

As may be seen in the drawing (Fig. 4), the plates 31 thus shaped enable the chain made up of the links 29 and constituting the semi-flexible member 25 to bend, resting on the wheel 27, but prevent the chain from bending in the opposite direction, so conferring on the chain 25 the characteristic of semi-flexibility.

In fact, the inclination of the surface 31 E and the inclination of the surface 31 F enable two adjacent plates 31 to be inclined with respect to one another until an angle is formed between them whereby the surface 31A of one plate impinges upon the surface 31 E of the other plate, and the surface 31 C of one plate impinges upon the surface 31 F of the other plate. Bending in the opposite direction is rendered impossible by the fact that the two surfaces 31 D and 31 B of the two adjacent plates impinge upon one another when the axes 29A of the two plates are aligned on the same plane.

The reciprocating rotation according to the double-headed arrow f27 of the wheel 27 in this way causes sliding of the slider 11 within the duct 1. The

slider 11 thus translates inside the duct 1 in the same way as a plunger connected to a cylinder-piston system of length and axial dimension much greater than the rotating actuator 27 described herein.

The slider 11 may be interchangeable together with the duct 1, and a number of sliders 13 of different diameters can be used as required each time in combination with respective ducts 1 according to the cross section of the elongated loose material that is to be handled by the machine. The replacement of the slider and of the duct can become necessary as a result of the change of the type of loose product and/or the change of the amount of product to be fitted into each package.

The loading section 3 of the machine has, in the example illustrated, two guide surfaces 41 and 43, which form a sort of hopper in which the loose material (for example, spaghetti or other long pasta P) drops into the duct 1 in the direction of the arrow F from a conveyor or chute (not shown) located higher up. In a position corresponding to the hopper formed by the guide surfaces 41 and 43, the duct 1 has a door or hatch 45 hinged, in 47, about a horizontal axis, or in any case an axis parallel to the duct 1. Two brackets 49 enable connection of the oscillating door 45 to an actuator (not shown) possibly via an appropriate lever mechanism. The actuator can consist of a brushless motor or of some other actuator means. Figs 6A and 6B show two positions that the oscillating door 45 can assume, i. e., respectively an open position for allowing the loose material to drop into the duct 1, and an almost closed position. Once complete closing of the oscillating door 45 has been achieved, pushing of the loose product inside the duct 1 by means of the pusher 11 is enabled. The oscillating door 45 co-operates with a piece made of shaped section 51 constituting a prolongation of the surface 41 and having a shape such as to prevent the loose product from getting stuck when the oscillating door 45 is closed.

Operation of the machine described so far is as follows. The oscillating door 45 is repeatedly opened by oscillation about the axis 47 in order to introduce, into the duct 1, at a position corresponding to the loading section 3, a weighted batch of loose product. Once this has dropped into the duct 1, the

oscillating door 45 is closed, and the loose product is pushed by the slider 11 along the duct 1 up to the section 9 for forming the package, where it is . t- packaged in a known way. The slider 11 then returns backwards until it frees the loading section 3, so as to enable-after prior opening of the door 45- loading of a new batch of loose product.. The reciprocating movement of the slider 11 along the duct 1 is obtained by means of an oscillating rotary motion of the actuator 27, with consequent winding and unwinding of the semi-flexible member 25 on the rotating actuator 27 itself. The slider 11 and the rotating actuator 27 together form the pusher for pushing the loose material inside the duct 1.

It is understood that the drawings only illustrates a possible embodiment of the invention, which may vary in its embodiments and arrangements without thereby departing from the scope of protection defined by the attached claims. The possible presence of reference numbers in the attached claims in no way limits the scope of protection, but merely has the purpose of facilitating reading of the claims reference being made to the foregoing description and the annexed drawings.