A concentric-ring single-sided dovetail groove ceramic tile back mold core is disclosed. A back mold core surface vulcanized rubber comprises raised patterns and recessed patterns integrally formed, pasted and covered on a back mold core iron substrate. The raised patterns are equidistantly offset outwards layer by layer with a central position of the back mold core as a center; and a side of each raised pattern close to the center is of an equiangular obtuse angle, and a side of each raised pattern far away from the center is of an acute angle with an angular equal difference gradually decreasing.

A press die for producing a clay roof tile, including a first die half and a second die half, which can move between a pressing position, in which they define a receiving space that represents the form of the finished roof tile, and a filling position, in which they are mutually spaced and the receiving space can be filled with a plastically deformable clay material. At least one of the first and the second die half has at least one depression which represents a projecting part of the finished roof tile; a first compression element is provided at the depression, and movable between an initial position, in which it is retracted in relation to the form of the finished roof tile, and a compacting position, in which some sections of the first compression element represent the surface of the finished roof tile.

A pressing device, comprising: a lower punch (10), provided with a pressing surface (10a) facing upwards; an upper punch (11), provided with a pressing surface (11a), facing downwards; at least one of the two punches is movable nearingly and distancingly relative to the other in order to perform pressing of a layer (L) of a ceramic material; a first movable belt (2) comprising an active portion (3) arranged at least partially between the upper punch (11) and the lower punch (10); a second movable belt (4) comprising an active portion (5) arranged at least partially between the first movable belt (2) and the upper punch (13); a shaped profile (6), which is so structured as to at least partially delimit a pressing chamber, which is detachably associated to the lower punch (10) or to the upper punch (11) in a projecting manner.

A format compensator for a pressing device, comprising a compensating element (7) of a given thickness (S), structured so as to be interposed between the lower punch and the upper punch (10, 11) of a pressing device so as to be arranged in contact with the punches (10, 11) during pressing.

A pressing device, comprising: a lower presser (10), provided with a pressing surface (10a) facing upwards; an upper presser (11), provided with a pressing surface (11a), facing downwards; at least one of the two pressers is movable towards and away relative to the other in order to perform pressing of a layer (L) of a ceramic material; a pressing space (V) delimited inferiorly and superiorly by the lower presser (10) and by the upper presser (11); a lower belt (2), movable along a forward direction (Y) and comprising an active portion (3) arranged at least partially between the upper presser (11) and the lower presser (10); an upper belt (4), movable along the forward direction (Y) and comprising an active portion (5) arranged at least partially between the lower belt (2) and the upper presser (11); two side barriers (13,14,15), arranged to laterally contain the layer (L) within the pressing space (V).

A press die for producing a clay roof tile, including a first die half and a second die half, which can move between a pressing position, in which they define a receiving space that represents the form of the finished roof tile, and a filling position, in which they are mutually spaced and the receiving space can be filled with a plastically deformable clay material. At least one of the first and the second die half has at least one depression which represents a projecting part of the finished roof tile; a first compression element is provided at the depression, and movable between an initial position, in which it is retracted in relation to the form of the finished roof tile, and a compacting position, in which some sections of the first compression element represent the surface of the finished roof tile.

A pressing device, comprising: a lower presser (10), provided with a pressing surface (10a) facing upwards; an upper presser (11), provided with a pressing surface (11a), facing downwards; at least one of the two pressers is movable towards and away relative to the other in order to perform pressing of a layer (L) of a ceramic material; a pressing space (V) delimited inferiorly and superiorly by the lower presser (10) and by the upper presser (11); a lower belt (2), movable along a forward direction (Y) and comprising an active portion (3) arranged at least partially between the upper presser (11) and the lower presser (10); an upper belt (4), movable along the forward direction (Y) and comprising an active portion (5) arranged at least partially between the lower belt (2) and the upper presser (11); two side barriers (13,14,15), arranged to laterally contain the layer (L) within the pressing space (V).

Manufacturing process of a stone providing for the following steps: positioning a die and a base platform under punches of a press, filling cavities of the die with a sand layer, placing a tube on the sand, actuating the actuation means to actuate the punches from the idle position to the operating position so that each punch presses the tube in the sand and presses the sand in the cavities of the die, actuating the actuation means to raise the punches, placing the stones in a drying station, extracting the solidified sand inside the tube from each stone, and placing a lighting device in the tube.

A pressing device, comprising: a lower punch (10), provided with a pressing surface (10a) facing upwards; an upper punch (11), provided with a pressing surface (11a), facing downwards; at least one of the two punches is movable nearingly and distancingly relative to the other in order to perform pressing of a layer (L) of a ceramic material; a first movable belt (2) comprising an active portion (3) arranged at least partially between the upper punch (11) and the lower punch (10); a second movable belt (4) comprising an active portion (5) arranged at least partially between the first movable belt (2) and the upper punch (13); a shaped profile (6), which is so structured as to at least partially delimit a pressing chamber, which is detachably associated to the lower punch (10) or to the upper punch (11) in a projecting manner.

A format compensator for a pressing device, comprising a compensating element (7) of a given thickness (S), structured so as to be interposed between the lower punch and the upper punch (10, 11) of a pressing device so as to be arranged in contact with the punches (10, 11) during pressing.