OTHER MACHINES

The present invention relates to a protective lining for walls of mills, mixers, hoppers and other machines, in particular a protective lining which can be applied to these walls for protecting them from moving material.

EP 1479442, EP 1810752 and EP 1990086 disclose protective linings comprising panels or other elastomeric members having a high wear resistance. For further improving the resistance, rigid inserts can be inserted in the elastomeric material before its vulcanization, as in the first embodiment of DE 2061554. For avoiding the accidental detachment of the rigid inserts from the panel which is partially worn out during the use, the inserts must be degreased with solvents and coated by one or more layers of a primer for allowing their perfect adhesion to the panel during the vulcanization. Said chemical treatments however increase the manufacturing costs and times, and further they are ecologically disadvantageous.

In the last four embodiments of DE 2061554 the base of a spike is snap-fitted into a seat made in an elastomeric panel. The tip of said spike protrudes from the panel and has a circular transversal section, so as to carry out a function substantially different from the function of said known rigid inserts.

GB 1431618 and WO 2007/054959 disclose a rigid layer snap-fitted onto an elastomeric layer, which thus does not comprise any functional protective surface. Therefore, the combined effect of rigid insert and elastomeric panel having coplanar protective surfaces, as in the first embodiment of DE 2061554, cannot be obtained.

US 2155215 discloses rigid inserts molten together with a metal panel. Since it is free from an elastomeric panel with a functional protective surface, also this known lining cannot be used as the lining according to the first embodiment of DE 2061554.

It is therefore an object of the present invention to provide a protective lining which is free from said disadvantages. Said object is achieved with a lining, whose main features are disclosed in claim 1, while other features are disclosed in the remaining claims.

Thanks to the snap-fit joints of the elastomeric panel and of the rigid insert, one or more inserts can be snap-fitted into particular seats made in the panel, so as to obtain a resistant coupling between panel and inserts without chemical treatments.

Thanks to the particular shape and to the particular arrangement of the joints, the coupling between panel and insert is maintained also when their protective surface is consumed by the use.

Preferably, the outer profile of the transversal section of the inserts is substantially constant, so that inserts with different sizes can be manufactured by cutting with different lengths a single piece having the same outer profile.

Furthermore, the inserts can be applied to the linings also after the vulcanization of the panel, even after the installation of the linings on the walls to be protected, so as to simplify their assembly, since the panels without inserts are lighter and thus easier to be raised for their installation.

According to a particular aspect of the invention, the synergic effect of the combination of the materials employed for the panel and for the inserts, as well as of their shapes and arrangements, allows to obtain a lining having a wear resistance which is much higher than the resistance of the known linings, also when they are provided with rigid inserts.

The protective surface of the insert is preferably flush with the protective surface of the panel around the seat which houses the insert, so as to reduce the consumption of electric energy during the milling and the wear of the milling means which come into contact with the lining.

Further advantages and features of the protective lining according to the present invention will become clear to those skilled in the art from the following detailed and non-limiting description of two embodiments thereof with reference to the attached drawings, wherein:

figure 1 shows a top view of the first embodiment of the lining;

figure 2 shows a side view of the lining of figure 1 ;

figure 3 shows an exploded side view of the lining of figure 1;

figure 4 shows a perspective exploded side view of the lining of figure 1;

- figure 5 shows a top view of the second embodiment of the lining; and

figure 6 shows a side view of the lining of figure 5. Referring to figures 1 and 2, it is seen that the lining according to the first embodiment of the present invention comprises in a known way an elastomeric panel 1, in particular made of rubber with a hardness comprised between 35 Shore A and 97 Shore A or of polyurethane with a hardness comprised between 35 Shore A and 55 Shore D. The outer surface of panel 1, namely the lower surface in the figures, is preferably provided with at least one shaped groove 2, for example with a transversal section having an outer profile substantially mushroom-shaped, for coupling panel 1 with a corresponding shaped profile fastened to the surface of the machine to be protected. The lateral surfaces of panel 1 are preferably provided with complementary grooves 3 and/or ridges 4 for coupling panel 1 with one or more adjacent panels. The protective surface of panel 1, namely the upper surface in the figures, which is the consumable surface which comes into contact with the material from which the machine has to be protected, can be provided with at least one protrusion 5, in particular a partially cylindrical bulge arranged along the shaped groove 2.

Referring to figures 3 and 4, it is seen that panel 1 is provided with one or more seats 6, 7 (shown with broken lines in figure 3) which are open at least toward the protective surfaces and are internally shaped toward the bottom for forming at least one snap-fit joint. In particular, said snap-fit joint comprises one or more flexible ribs 8, 9 projecting from lateral surfaces of seats 6, 7 and having one or more rounded edges. Base 10 of seats 6, 7 is tapered toward the bottom.

In the present embodiment, one or first seats 6 comprise at least two parallel ribs 8, 9 projecting from opposite lateral surfaces. First seats 6 are substantially parallelepiped-shaped and are arranged in a substantially parallelepiped portion of panel 1 along parallel columns and/or offset rows, in particular with a quincuncial arrangement. One or more second seats 7 are substantially arc-shaped and are arranged in protrusion 5 of panel 1. Second seats 7 comprise at least two pairs of flexible ribs 8, 9 arranged one parallel to the other at the ends of the arc of second seats 7. Second seats 7 are also arranged parallelly along protrusion 5, so that shaped groove 2 is arranged in the arc of second seats 7.

One or more protective inserts 11, 12 made of a rigid material, in particular a sintered ceramic material with a content of alumina equal to or higher than 80%, a density equal to or higher than 3,1 g/cm ³ and a Rockwell 45N hardness equal to or higher than 70, namely a material more rigid than the material of panel 1 , are suitable for being arranged in seats 6, 7, respectively, of panel 1 and have a shape substantially complementary to these seats, namely substantially parallelepiped- or arc-shaped, so that inserts 11, 12 do not protrude from the respective seats 6, 7 and the protective surface of an insert 11, 12 is flush with the protective surface of panel 1 around seat 6, 7 which houses insert 11, 12, as it is clearly shown in the figures. For this purpose, the base of protective inserts 11, 12 is provided with at least one snap -fit joint suitable for being inserted into the snap-fit joint of seats 6, 7. The snap-fit joint of protective inserts 11, 12 comprises one or more grooves 13, 14 which are made along lateral surfaces of inserts 11, 12 and have one or more rounded edges, so as to be easily coupled with flexible ribs 8, 9 of seats 6, 7 of panel 1. Base 15 of inserts 11, 12 is tapered, so as to easily bend flexible ribs 8, 9 for carrying out the snap-fit coupling. The distance between grooves 13, 14 and the protective surface of inserts 11, 12 is substantially equal to the distance between flexible ribs 8, 9 and the protective surface of panel 1.

In the present embodiment, first inserts 11 are substantially parallelepiped-shaped and are snap-fitted into first seats 6 of panel 1 thanks to at least one pair of parallel grooves 13, 14 made along opposite lateral surfaces of first inserts 11. Second inserts 12 are substantially arc-shaped and are snap-fitted into second seats 7 of panel 1 thanks to at least two pairs of parallel grooves 13, 14 made at the ends of the arc of second inserts 12. Panel 1 is preferably vulcanized before inserts 11, 12 are inserted therein.

Referring to figures 5 and 6, it is seen that the lining according to the second embodiment of the invention comprises an elastomeric panel 16 made of the same material of panel 1 but with a substantially circular or annular, in particular annular, sector shape. The outer surface of panel 16 is preferably provided with one or more shaped grooves 17 (shown with broken lines in figure 5) which are arranged along radial axes, while the lateral surfaces are preferably provided with complementary grooves 18 and/or ridges 19.

Panel 16 is provided with one or more seats which are open at least toward the protective surface and are internally shaped for obtaining a snap-fit joint similar to the joint of seats 6. Said seats, as well as the ribs of the relevant snap-fit joints, are arranged along radial axes of panel 16. Protective inserts 20 made of the same material and shaped substantially with the same transversal section of inserts 11 are snap-fitted into the seats of panel 16.

The outer profile of the transversal section of inserts 11, 12, 20 is substantially constant along a longitudinal axis thereof. In the same way, the inner profile of the transversal section of seats 6, 7 of panel 1, as well as of the seats of panel 16, is substantially constant along a longitudinal axis thereof.

Possible modifications and/or additions may be made by those skilled in the art to the hereinabove disclosed and illustrated embodiments while remaining within the scope of the following claims.