ROTARY PRESS MACHINE FOR THE PRODUCTION OF PRESSED

PRODUCTS

Technical field

This invention relates to a rotary press machine for the production of pressed products.

More specifically, this rotary press machine for pressed products is used for the formation of solid food products in the form of pressed stock cubes, such as those with a cubic or in any case polyhedral shape.

Background art

The rotary press machines currently comprise a circular compression turret, rotating around a vertical axis.

The turret comprises a table equipped with a plurality of dies arranged along its circumference and with which are combined a plurality of pressing punches supported and guided by an annular bell positioned on a plane lower than the die table. Each die has the geometrical shape corresponding to that of the desired end product.

The machine also comprises a dosing station for dosing a product to be pressed in the dies.

The product is fed (in powder or granular form) from the top towards each of the dies, whilst the respective punches act as a lower base to keep the product inside the die.

The machine comprises a primary unit or drive configured to rotate the compression turret around the axis of rotation, in such a way that the plurality of dies and the punches move along a common closed pressing path, in particular a circular path.

The machine also comprises a compression station equipped with:

- a compression unit (positioned below the punches) configured for moving the punches inside the respective dies for compressing the product to be pressed;

- at least one pressing plate positioned at the free surface of the table and opposite the punches.

There are usually two pressing plates, in succession along the closed path, for performing a first and a second pressing along the path of the table.

Each pressing plate comprises a supporting shaft with a vertical axis on which the respective pressing plate is keyed and rotatable.

According to a first prior art solution, each pressing plate is keyed freely rotatably on the supporting shaft and its rotation (in the opposite direction to the direction of rotation of the table) occurs by a friction generated by contact with the material of the product being compressed pushed upwards by the punches (true?).

According to a second prior art solution, each pressing plate is connected to a dedicated drive unit and configured to rotate the pressing plate around its vertical axis of rotation (parallel to the axis of rotation of the axis of rotation of the table).

However, these two solutions for moving the or pressing plate(s) have drawbacks.

The pressing plates moved by friction with the granular product may have speeds of rotation which are not constant with sudden decelerations and accelerations as a function of the contact with the product and with consequent increase in temperature of the material of the pressing plate. These two factors, speed and temperature, tend to accelerate a phenomenon of wear of the pressing plate with consequent machine stoppages for their replacement. In addition to this factor, there is the fact that the pressing plate with an irregular speed can determine an incorrect compression of the product with potential reduction in the quality of the final product.

The pressing plates with independent drive units have a greater regularity of rotation speed, but require a bulkier structure inside the machine and a system for controlling the components which is more complex and combined with the drive unit of the compression table.

These factors therefore make the machine bulkier and more costly also due to the maintenance necessary on a large number of drive units present on the machine.

Aim of the invention

The aim of the invention is to provide a rotary press machine for the production of pressed products which overcomes the above-mentioned drawbacks of the prior art.

More specifically, the aim of the invention is to provide a rotary press machine for the production of pressed products which is able to reduce the overall dimensions of the machine and at the same time maintains a high production speed.

A further aim of the invention is to provide a rotary press machine for the production of pressed products structured in such a way as to guarantee coordinated speeds between the rotary components without affecting the overall costs of the machine.

Said aims are fully achieved by the rotary press machine for the production of pressed products according to the invention as characterised in the appended claims.

Brief description of the drawings

These and other features of the invention will become more apparent from the following detailed description of a preferred, non-limiting embodiment of it, with reference to the accompanying drawings, in which:

- Figure 1 is a schematic perspective view, with some parts cut away to better illustrate others, of a rotary press machine for the production of pressed products;

Figure 2 is a top plan view, with some parts cut away in order to better illustrate others, of the press machine of Figure 1 ;

Figure 3 is a side view, with some parts cut away in order to better illustrate others, of the press machine of the preceding drawings;

Figure 4 is a schematic front view, with some parts cut away in order to better illustrate others, of the press machine of the preceding drawings.

Detailed description of preferred embodiments of the invention

With reference to the accompanying drawings, and with particular reference to Figures 1 and 2, the rotary press machine according to the invention for the production of pressed products is denoted in its entirety by the numeral 100.

Preferably, but not necessarily, this rotary press machine for pressed products is used for the formation of solid food products in the form of pressed stock cubes, such as those with a cubic or in any case polyhedral shape.

The machine 100 comprises a rotary compression turret 1 having a die table 2 provided, along a circumference of it, with a plurality of dies 3 and a respective plurality of punches 4.

According to this invention, the term dies is also used to mean the pockets made directly on the table 2.

Each die 3 is made / applied on the perimeter (annular) surface of the table 2 and has a shape correlated with the final shape of the product to be formed.

Each punch 4 has a pressing head with a shape matching the die 3.

The machine 100 comprises a primary movement unit 5 configured to rotate the compression turret 1 around a first axis of rotation X1 , in such a way that the plurality of dies 3 and punches (4 move along a common closed pressing path (circular path).

The machine 100 comprises a dosing station 6 for dosing a product 7 to be pressed in the dies 3.

The dosing station 6 doses the powdered or granular product in the dies 3 from the top down.

The machine 100 also comprises a compression station (see also Figure 4) provided with a compression unit 8 configured to move the punches 4 inside the respective dies 3 to compress the product to be pressed.

The compression station comprises at least one pressing plate 9 opposite the punches 4 and with the dies 3 interposed between the punches 4 and the pressing plate 9.

The machine 100 comprises a secondary movement unit 10 configured to rotate the at least one pressing plate 9 around a second axis of rotation X2 parallel to the first axis of rotation X1.

As illustrated, the secondary movement unit 10 comprises at least one rotatable member 11 acting in conjunction with the punches 4 in such a way that the rotary movement of the punches 4 around the first axis of rotation X1 rotates the at least one rotatable member 11 around a third axis of rotation.

Again as illustrated, the at least one rotatable member 11 is in turn connected to the at least one pressing plate 9 for rotating it around the second axis of rotation X2.

In other words, the pressing plate 9 takes the motion, thanks to the rotatable member 11 , from the movement of the punches 4. This system allows a precise phase coordination in the relative rotation speeds between the turret 2 and the pressing plate 9 without the need for further independent drive units.

It should be noted that the turret 2 is rotated, in the case illustrated in a direction V, in this case anticlockwise.

The rotatable member 11 and the pressing plate 9 rotate due to their kinematic connection in a direction V1 opposite to the direction V of the turret 2 (in this case, a clockwise direction).

Preferably, the rotatable member 11 comprises a rotating starwheel provided with a plurality of recesses 12 shaped to mesh with the punches 4 while it rotates around said third axis of rotation. The geometrical profile of the recesses 12 of the starwheel allows a matching meshing due to the cylindrical cross-section of the punches 4 which allows a thrust on the inner surface of each recess 12 during their passage so as to obtain a continuous rotation of the starwheel and consequently of the pressing plate 9.

As illustrated, the third axis of rotation is parallel to the first axis of rotation X1 and to the second axis of rotation X2.

In light of this, the second axis of rotation X2 coincides with the third axis of rotation.

Preferably, the rotatable member 11 and the pressing plate 9 are keyed to a common rotational shaft 13.

It should be noted that the pressing plate 9 is keyed (vertically) on the rotational shaft 13 rotatably supported by a frame.

The shaft 13 extends beyond the pressing plate 9 (in this case downwards) and is connected to the rotatable member 11 (the starwheel) to allow the passage of motion to the pressing plate 9.

It should be noted that each punch 4 is housed in the respective die 3 along a respective longitudinal axis parallel to the first axis of rotation X1. In Figure 3 the numeral X4 denotes a single longitudinal axis of a punch 4. In light of this, the plurality of punches 4 is supported by a circular bell 14, consisting of a plate, provided with a plurality of hollow guides 15 (through holes) slidably engaged by the plurality of punches 4.

The circular bell 14 lies in a parallel plane and at a different height to the plane in which the die table 2 lies.

It should be noted that the rotatable unit 11 of the pressing plate 9 is positioned in the space between the two planes in which the bell 14 and the die table 2 lie.

In light of this, the circular bell 14 rotates around the first axis of rotation X1.

The rotary member 11 is therefore positioned in an area already present in the structure of the turret 1 and, thanks to the constant presence of the punches 4, the motion necessary for moving the pressing plate 9 is obtained.

According to the accompanying drawings, the structure of the machine 100 comprises two pressing plates (labelled 9 and 16) positioned one after the other with reference to the direction of rotation of the die table 2 and along the surface of the table 2 for holding the dies 3.

The first pressing plate labelled 9 determines a first pressing (or pre pressing) of the product 7 in the dies 3, whilst the second pressing plate 16, having a diameter greater than the diameter of the pressing plate 9, determines the second pressing (final pressing).

The second pressing plate 16 comprises a structure similar to the first pressing plate 9.

In light of this, the second pressing plate 16 comprises a second supporting shaft 17 (rotating around an axis X17) and a second rotatable means 18 kinematically connected to the second shaft 17 and acting in conjunction with the punches 4.

The second rotatable member 18 comprises a rotating starwheel provided with a plurality of recesses 19 shaped to mesh with the punches 4 in such a way as to allow a rotation around its axis of rotation X17 (parallel to the axis of rotation of the rotatable member 11) in a manner similar to that described for the other rotatable member 11.

As shown in Figure 4, the compression turret 1 comprises, below the table 2 for holding the dies 3, the above-mentioned bell 14 for supporting the punches 4.

The bell 14 is provided with a cam profile 20 in which a plurality of cam follower bases 21 integral with the plurality of punches 4 slide.

At the zone of compression of the product 7 along the closed circular path of the table 2 for holding the dies 3 there are two pre-compression 22 and compression 23 rollers configured to allow a thrust on each punch 4 in transit along a direction perpendicular to the feed direction of the punch 3 which is able to move the punch 4 inside the die 3 (at that moment facing the first 9 or the second 16 compression plate) to allow compression of the product 7.

Each roller 22 or 23 generates the thrust on the punch 4 through a tangential contact with the cam follower base 21.

A method is also described for the production of pressed products in a rotary press machine 100 comprising the rotary compression turret 1 having the die table 2 provided along a circumference of the plurality of dies 3 and a respective plurality of punches 4.

The method comprises the following steps:

- rotating the compression turret 1 with continuous motion around a first axis of rotation X1 , in such a way that the plurality of dies 3 and punches 4 move along a common closed pressing path;

- dosing in the dies 3 the product 7 to be pressed;

- compressing the product 7 dosed in the dies 3 by moving the punches 3 against at least one pressing plate 9 with the product 7 interposed between the pressing plate 9 and the punch 4;

- rotating the pressing plate 9 around a second axis of rotation X2 parallel to the first axis of rotation X1.

The step of rotating the pressing plate 9 is performed by means of the rotatable member 11 acting in conjunction with the punches 4 in such a way that the rotary movement of the punches 4 around the first axis of rotation X1 rotates the rotatable member 11 around the third axis of rotation.

The rotatable member 11 is in turn connected to the pressing plate 9 for rotating it around the second axis of rotation X2.

Preferably, the rotatable member 11 is rotated by meshing with the punches 4.

The press machine structured in this way therefore fully achieves the preset aims thanks to the presence of a rotatable member which is capable of taking motion from the movement of the punches and thus obtains the rotation of the pressing plate. This system allows the pressing plate(s) to be moved in synchrony without the need for further and expensive independent drive systems.

Further, the structure of the turret allows the motion transmission starwheel to be positioned in a relatively free zone and always present (space between the die table and the punch supporting bell necessary for the working strokes of the punches) without altering the structure of the press machine.