Method of operating a stamping press
AssigneeBlackfoil Group Limited
InventorMichael Adrian Castleton
Life of this patent
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Abstract
A stamping press has a pair of plates defining a press gap between them, a hydraulic ram to produce relative movement between the plates to close the press gap and apply pressure to the die against a substrate in the gap, a hydraulic pump driven by an electric motor through a flywheel means for shutting off the motor on reaching a predetermined pressure in the circuit, and a dump valve for dumping hydraulic pressure from the circuit.
Claims5
A method of operating a stamping press which has a pair of plates defining a press gap between them, and a hydraulic ram to provide relative movement between the plates to close the press gap and apply pressure to a die to press the die against a substrate in the gap, wherein the hydraulic ram is fed with hydraulic fluid from a pump driven by an electric motor, the method comprising the steps of driving the motor to pressurize the hydraulic ram to a pressure below a maximum pressure to be achieved, shutting off electric current to the motor and allowing the motor to continue to run under its own inertia until it stalls to pressurize the hydraulic ram to a higher pressure, and opening a dump valve to dump the pressure after a predetermined time period after the motor stalls.
A method as claimed in any preceding claim, wherein the press is operated so that when the pressure in the hydraulic ram reaches the pressure below the maximum pressure, a first timer is started and after a pre-set time period electric current to the motor is switched off.
Dependencies are inferred from the claim text.