(57) A hydraulic device, typically for ceramic moulds comprising a vertically mobile bottom
die (24) provided with cavities (21) for loading the soft clay and a counter-die (240)
provided with corresponding cavities (210), said cavities (21), (210) being closed
at their rear by respective punches (20), (200) for forming the laying and exposed
faces of the tiles respectively, said punches (20), (200) being connected to the hydraulic
circuit of the press which operates the ceramic mould, in such a manner as to be driven
independently of said bottom die and counter-die, comprises two intercommunicatlng
chambers (122, 22) with a valve (4) therebetween, the first (122) being connected
to the hydraulic circuit (66) for driving the lower punches (20) relative to the bottom
die (24), and the second (22) being connected to at least one hydraulic chamber (280)
for driving the upper punches (200) relative to the counter-die (240). The valve (4)
is elastically urged towards a forward slidable push rod (5, 6) the seat of which
is connected to said first chamber (122) such that when this latter is put under pressure
by the hydraulic fluid from said circuit (66) the push rod (5, 6) causes the valve
(4) to open with simultaneous fluid entry into said hydraulic chamber (280) and advancement
of the upper punches (200). When the upper punches (200) move rearwards during a pressing
stage, the valve (4) closes after fluid discharge from said hydraulic chamber (280).
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