The present invention can be used advantageously for supporting a rotating thrusting roller employed in pressing machines comprising at least two opposite and counter-rotating rollers.

The device is therefore suitable for use in the rolling of ductile materials, pressure compaction and drying and may be advantageously applied to continuous-cycle operating machines.

Background art In many production processes it is required to compress continuously and for a certain period of time an object or a product being processed. In most cases this is obtained by passing continuously the object to be processed through one or more facing rollers rotating on parallel axes in opposite directions, in such a way as to exert on said rollers a pressure in a direction perpendicular to their contact surface.

Generally the facing rollers are supported at their ends by means of bearings which are in turn fixed to suitable supports.

Fig. 1 shows a simple known arrangement of a roller thrusting or pressing assembly comprising a first fixed roller A and a second movable roller B which are supported at their ends by lever arms C pivotably mounted at D. Pressure means,

consisting for example of an hydraulic cylinder E, act on the other arm of the levers C so as to compress the movable roller B against the fixed roller A.

An object to be processed P is passed between the roller A, B and is subjected to a continuous pressure between the opposite surfaces of these rollers.

A drawback of this known arrangement consists in the relative complexity and the excessive number of mechanical components which must be suitably dimensioned to withstand the various stresses.

A further drawback consists in the large volume of the device as a whole, especially in production zones where a small amount of space must be occupied.

Summary of the invention The main object of the present invention is to eliminate or at least reduce the drawbacks mentioned above by providing a support device for a roller, with a thrusting device, composed of a small number of parts.

A particular object is that of allowing the manufacture of a strong, compact and small-volume structure.

Another object is that of providing a support device which has high reliability and durability characteristics at a low cost.

These objects, together with others, which will appear more clearly below, are achieved by a roller support device which can be applied to a thrust roller assembly of the type comprising a movable roller acting against a fixed roller by suitable pressure means so as to compress an object arranged in between, said support device being characterized in that it comprises, in the region of the support zone of said movable roller, a bearing which is slidably mounted on guide means

having a rectilinear sliding direction substantially parallel or selectively inclined with respect to the line joining the axes of said rollers.

Thanks to this arrangement, the device has a small number of components and extremely small overall dimensions compared to the known support devices of the prior art, being devoid of bulky levers and being particularly compact and strong.

Brief description of the drawings Further features and advantages of the invention will be more clearly understood in the light of the following detailed description of several preferred, but not exclusive embodiments of a roller support device, illustrated by way of a non- limiting example with reference to the attached drawings sheets in which: FIG. 1 shows a schematic side view of an embodiment of a pressing assembly according to the prior art; FIG. 2 shows a schematic side view of a pressing assembly which uses a support according to the invention; FIG. 3 shows a cross-section through a first embodiment of the support device according to Fig. 2; FIG. 4 shows an axial section through the support device of Fig. 3; FIG. 5 shows a cross-section through an isolated detail of Fig. 3; FIG. 6 shows a cross-section through a second embodiment of the support according to the invention.

Detailed description of some preferred embodiment (s) With reference to Figures 2 to 6, a support device according to the invention, generally indicated with the reference number 100, is mounted on a thrust roller assembly which essentially comprises a fixed roller 1 mounted by means of end supports on a stationary column 101 and a movable column 2 mounted on the support device 100.

The support device 100 comprises inside it pressure means-not shown in the drawings and of a type known per se-acting on the roller 2 so as to press it against the fixed roller 1 with a force 40.

According to the invention, the support device 100 comprises, at each end of said movable roller 2, a bearing 3, for example, but not necessarily of the roller type 4, with an external thrust piece 5 mounted slidably on guide means-indicated overall by 6-having a rectilinear sliding direction C substantially parallel or selectively inclined with respect to the line joining the axes of said rollers.

The guide means 6 comprise a slide 7 associated with the external thrust piece of the bearing 3 with a predetermined maximum travel 8 in the abovementioned sliding direction.

The slide 7 comprises a movable annular element 8 which can be fixed peripheral to the external thrust piece 5 of the bearing 3 and is provided on its outer cylindrical surface with at least one flat sliding surface 9.

In particular, the movable annular element 8 comprises a pair of flat sliding surfaces 9', 9"formed in diametrically opposite positions on its outer cylindrical surface.

In a first embodiment, the flat sliding surfaces are formed by a pair of cut-away portions 12,12"of material along the periphery of said movable annular element 8 in the form of a circular segment of predetermined camber T.

The guide means comprise an annular element or support 10, having a central hole or cavity C which is substantially circular and intended to house the movable annular element 8, and flat opposite guide surfaces 10', 10"intended to guide slidably the flat sliding surfaces 9', 9".

The flat guide surfaces 10', 10"are formed on a pair of radial projections 11 in the form of a circle segment, in diametrically opposite positions on the internal cavity C of the annular element or fixed support 10.

In a first preferred embodiment, the radial projections 11 are formed by a pair of inserts 11', 11"which can be fixed in diametrically opposite positions along the surface of said internal cavity C of said fixed annular element 10.

Each radial projection 11', 11"has a cross-section in the form of a circle segment of predetermined high R.

Advantageously, the sum of the highs R of the inserts 11', 11"is at least equal to the sum of the highs T of the radially cut-away portions 12 plus the maximum travel S of the guide means.

The maximum travel S is equal to the distance between the minimum diameter D of the said internal cavity C of said fixed annular element and the maximum diameter F of the movable annular element 8.

Advantageously, the fixed annular element 10 and the movable annular element 8 have the same axial thickness so as to form laterally closed pressure chambers which will be described in more detail below.

The external diameter of the circle segments 11', 11"coincides with the internal diameter d'of the fixed support 10 and their flat part is in direct contact with the corresponding flat surface formed on the outside of the annular element 8 with removal of the two circle segments 12.

Of course, the central cavity C of the annular element or fixed support 10 may also be obtained by removing directly the material inside the support 10 so as to obtain the same configuration described above.

In this case, however, the direction of movement of the internal support 9 is predefined and cannot be modified as would instead be possible if the two circle segments 11', 11"can be suitably positioned at a predefined angle a with respect to the line L joining the axes of the rollers 1,2 as can be seen in Fig. 6, so as to determine a given direction of reaction with respect to the direction L.

The annular element 8 is therefore free to move both ways in the direction L parallel to the flat surfaces of the two circle segments 11, until the space left free by the difference in the internal diameter d'of the fixed support 10 and the external diameter d of the annular support 9 is taken up.

Two chambers 15 and 16, with a cross-section in the form of angular section of a circular rim, are thus formed.

The introduction, into one or both the chambers 15 and 16, of a fluid under pressure, for example oil or compressed air, produces a thrust which moves the annular support 9 in the desired direction, parallel to the flat surfaces of the segments 11. The lateral pivot of the movable roller is driving during its movement. In this way a force is produced against the fixed opposition roller.

The sealing action of the pressurised chambers 15 and 16 against the circle segments 11 is obtained by reducing to a minimum the free space between the flat surfaces of the circle segments 11', 11"and the corresponding flat surface of the annular element 8, thus allowing a small quantity of fluid under pressure to pass through the resultant space between the corresponding flat surfaces of the circle segments 11', 11"and the annular element 8.

Preferably, the space between the flat surfaces of the circle segments 11 and the flat surface of the support 9 is equal to about 0.05 mm. Advantageously, oil is used as the pressurised fluid inside the chambers 15 and 16 and seepage through the slit ensures efficient lubrication of the two flat surfaces which slide against each other.

As shown in Fig. 3, two chambers 21 and 22 are formed over the whole width of the circle segments 11, in the central zone of the flat lateral surfaces of the support 8, said chambers collecting both the fluid passing through the slits between the circle segments 11 and the support 9 and the fluid passing between the front surfaces of the circle segments 11 and the side walls 13 and 14. The fluid thus collected is drained via the ducts 23 and 24 or using some other equivalent drainage system.

As illustrated in Fig. 4, the sealing action of the pressurised chambers 15 and 16 with respect to the lateral surfaces 13 and 14 is achieved by means of ordinary seals 17,18,19,20 which are arranged in an arc of a circle in the vicinity of the external diameter of the support 8 and extend over the whole length of the said arc.

The seals thus obtained are not completely fluid-tight. The fluid passing out at the ends of the seals 17,18,19,20 and between the front flat surfaces of the circle segments 11 and the front walls 13 and 14 is thus collected inside the two annular chambers 27 and 28 where the oil which lubricated the bearing 3 is also collected.

Two front annular seals 25 and 26 are therefore provided between the rings 29 and 30 fixed to the fixed support and the movable elements 31 and 32. These elements are guided by the rings 33 and 34 integral with the movable support 9 so as to move at the same time as and in a similar manner to the shaft 7 of the roller which is supported by the support. The movable elements 31 and 32 on the one hand slide against the external surface of the side walls 13 and 14 and on the other hand against the front annular seals 25 and 26 and also form a seal with respect to the rotating shaft 7 by means of the seals 35 and 36.

Inside the chambers 27 and 28 there is no pressure. In this way a perfect seal with respect to the exterior is ensured. The oil which collects inside the two chambers 27 and 28 is then drained externally via the ducts 37 and 38.

Lubrication of the bearing 3 may be performed directly by one of the two pressurised chambers 15 and 16 via the calibrated duct 39.

Positioning of the two circle segments 11', 11"may be performed either by fixing them rigidly to the fixed support 10 in a position exactly opposite each other or more advantageously by fixing them rigidly to the lateral surface 13.

With this arrangement, by angularly positioning the lateral surface 13 in a suitable manner, it is possible to orient in any direction the movement and the thrust of the annular element 8 in the sliding direction L.

The embodiment shown in Fig. 6 differs from that in Fig. 3 precisely with regard to the angle of inclination of the line of sliding L with respect to the line joining together the centres of the axes of the rollers 1 and 2.

Even though the support device according to the invention has been described with particular reference to the accompanying drawings, it may be subject to numerous modifications and variations which fall within the inventive idea expressed in the accompanying claims and are also regarded as protected.

Moreover all the details may be replaced by technically equivalent elements and the materials may vary in accordance with requirements.