(57) Improvement in a spool of a copying distributor in a hydraulic circuit (3) for controlling
the motion of a cylinder for a hammer (4) in a punching machine, including a pressurized
fluid source (24a) in communication with said hydraulic circuit (3), a distributor
body (5) which is connected to said hydraulic circuit through pipe fittings and is
formed with pressurised-fluid supply lights (6, 33) and discharge light (7) communicating
with said pipe fittings, at least one valve means (9) arranged in said hydraulic circuit
to control the said distributor body (5), a spool (1) slidably mounted in said body
(5) and arranged cyclically to open and close the said lights (6, 33, 7), one operating
end (11) of said spool (1) extending outside said distributor body (5) through a calibrated
aperture (12) and being arranged to abut against a reference member (13) designed
to move rigid with said hammer (4). The improvement provides for a recess (14) formed
in said operating end (11) and having one end (15) thereof blind and its other end
(16) open, a pin (17) slidably mounted in said open end (16) and arranged to be displaced
therein by pressurised fluid flows controlled by said valve means (9), and at least
one duct (18) formed in said distributor body (5) and arranged to feed pressurised
fluid from said fluid source (24a) to said recess (14).
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