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AssigneeTa-Ro Progetti S.N.C. Di Tagliati Rodolfo E C.
InventorsDaniele TAGLIATI, Davide Tagliati, Michele Tagliati
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An isostatic die for tile forming comprising a metal body (2) and an elastically deformable membrane (6, 6′, 6″) which is solidly gripped to the metal body (2) in a plurality of distinct predetermined fixing zones (25, 28, 290, 21, 22, 24′, 24″), such that an intermediate hermetically sealed chamber is delimited between the elastic membrane (6, 6′, 6″) and the metal body (2), which chamber is destined to contain an incompressible fluid. Rigid bushings (5, 5″) are sunk into the elastic membrane (6, 6′, 6″), each of which rigid bushings (5, 5″) is located at a fixing zone (25, 28, 290, 21, 22, 24′, 24″) of the elastic membrane (6, 6′, 6″) to the metal body (2), and defines a breather mouth lo (52) which passes into a body of the elastic membrane (6, 6′, 6″) and which communicates with an outside environment through a system of discharge conduits (9) afforded in the metal body (2), each rigid bushing (5, 5″) receiving a respective obturator body (7), which obturator body (7) enables passage of air and at least partially prevents passage of ceramic powder.
1). An isostatic die for tile forming comprising a metal body (2) and an elastically deformable membrane (6, 6′, 6″) which is solidly gripped to the metal body (2) in a plurality of distinct predetermined fixing zones (25, 28, 290, 21, 22, 24′, 24″), such that an intermediate hermetically-sealed chamber is delimited between the elastic membrane (6, 6′, 6″) and the metal body (2), which chamber is destined to contain an incompressible fluid, characterised in that rigid bushings (5, 5″) are sunk into the elastic membrane (6, 6′, 6″), each of which rigid bushings (5, 5″) is located at a fixing zone (25, 28, 290, 21, 22, 24′, 24″) of the elastic membrane (6, 6′, 6″) to the metal body (2), and lo defines a breather mouth (52) which passes into a body of the elastic membrane (6, 6′, 6″) and which communicates with an outside environment through a system of discharge conduits (9) afforded in the metal body (2), each rigid bushing (5, 5″) receiving a respective obturator body (7), which obturator body (7) enables passage of air and at least partially prevents passage of ceramic powder.
2). The die of claim 1, characterised in that each obturator body (7) is constituted by a compact body which partially obstructs the breather mouth (52) of the relative rigid bushing (5, 5″), leaving a narrow passage fissure perpetually open.
3). The die of claim 2, characterised in that the narrow fissure is of such a size as to enable passage of air during a pressing stage and to limit infiltration therein of the ceramic powder.
4). The die of claim 1, characterised in that the obturator body (7) is solidly fixed to the metal body (2) of the isostatic die, such as to be stationary with respect to the rigid bushing (5, 5″).
5). The die of claim 1, characterised in that the obturator body (7) is associated to respective means for activating (70, 71, 41) which move the obturator body (7) alternatingly between a rest position, in which it is internal of the relative rigid bushing (5), and an extraction position in which it projects externally thereof.
6). The die of claim 5, characterised in that each obturator body (7) is fixed to an end of a valve stem (70) which valve stem (70) is slidable in a hole (4) which is afforded in the metal body (2) behind the respective rigid bushing (5).
7). The die of claim 6, characterised in that the valve stem (70) comprises a scraper body (75) which is coaxial to the obturator body (7) and is lo transversally larger, which scraper body (75) passes substantially snugly internally of the breather mouth (52), during displacement of the obturator body (7) from the rest position to the extraction position thereof, such as to push any ceramic powder which may be present in the breather body (52) in an externalwise direction.
8). The die of claim 6, characterised in that the means for activating comprise a portion of the valve stem (70) which, operating as a piston, is pushed by a pressurised fluid to slide internally of a relative cylindrical seating (41) afforded in the metal body (2).
9). The die of claim 8, characterised in that each valve body (7) is associated to means for recall (74) which return the valve body (7) to the rest position thereof.
10). The die of claim 9, characterised in that the means for recall comprise a spring (74) which acts on the piston in contrast to the pressurised fluid.
11). The die of claim 9, characterised in that the means for recall comprise an auxiliary hydraulic circuit which supplies pressurised fluid into the cylindrical seating (41) in order to push the piston in an opposite direction with respect to the extraction direction.
12). The die of claim 8, characterised in that the cylindrical seatings (41) of all the means for activating the valve bodies (7) are hydraulically connected through a same conveying conduit (8) of the pressurised fluid.
13). The die of claim 8, characterised in that the cylindrical seatings (41) of the means for activating the valve bodies (7) are hydraulically connected to a plurality of independent conduits (8) for conveying the pressurised fluid.
14). The die of claim 1, characterised in that each rigid bushing (5, 5″) is inserted in a respective through-hole in the elastic membrane (6, 6′, 6″), and exhibits a circumferential channel (51, 51″) by which it couples with a rib (60, 60′, 60″) of the elastic membrane (6, 6′, 6″) which rib (60, 60′, 60″) projects from an internal wall of the through-hole.
15). The die of claim 1, characterised in that an end of the rigid bushing (5, 5″) is in line with an active surface of the elastic membrane (6, 6′, 6″).
16). The die of claim 1, characterised in that the metal body (2) exhibits a hollow (23) conformed in plan view as a grid, in which a grid (3) of a suitable shape is housed, which grid (3) is more rigid than the elastic membrane (6) and is interposed between the elastic membrane (6) and the incompressible fluid chamber,
17). The die of claim 16, characterised in that the face of the elastic membrane (6) which is close to the grid (3) exhibits a grid in relief which snugly inserts in the hollow (23) of the metal body (2).
18). The die of claim 16, characterised in that the grid (3) is strongly gripped to the elastic membrane (6, 6′, 6″).
19). The die of claim 16, characterised in that the grid (3) is made of an elastomer material.
20). The die of claim 1, characterised in that each of the fixing zones comprises a grooved cavity (28) afforded in the metal body (2) in which a corresponding protuberance in relief of the elastic membrane (6′) is snugly coupled.
21). The die of claim 1, characterised in that each of the fixing zones is delimited by a respective annular channel (290) afforded in the metal body (2), in which annular channel (290) a respective annular rib in relief of the elastic membrane (6″) is snugly coupled.
22). The die of claim 1, characterised in that the discharge conduit system (9) is connected to an aspirating device, which aspirates any ceramic material possibly present in the discharge conduits (9).
23). The die of claim 1, characterised in that the discharge conduit (9) system is connected to a blower device, which injects pressurised air internally of the discharge conduits (9).