| 摘要 |
<p>1,212,953. Electromagnetic presses. AMP Inc. 17 April, 1969 [3 May, 1968], No. 19658/69. Heading B3H. An electromagnetic press comprises a ram 24 with a die 20 to compress a workpiece against a die 50, tractive electromagnets 30, 32 to drive the ram and means to control the signal to the electromagnets to control the compression. The die 50 is mounted on a piezo-electric transducer 52 to produce a signal dependent on the compression force. The lower electromagnet 30 is fixed to the press frame 18 and has a plastics buffer plate 34 against which the other electromagnet 32 hits. The electromagnet 32 is fixed to the ram 24 and the ram is spring-biased upwards. The windings WI, WII are energized to move the ram downwards and the force exerted against a ferrule F to be crimped on to a wire L is transmitted to the transducer whose signal is fed to the power supply. Alternatively, the transducer is omitted and the windings supplied with a current pulse. The connectors C may be fed to the press in a strip which is sheared by the dies. The magnetic material of the electromagnets may become saturated before the end of the stroke. The ram force, velocity, acceleration, dwell time and stroke can be regulated by controlling the current applied to the windings. A power source (60), Fig. 4 (not shown), is connected to a pulse control device (62) which is connected to the press actuator 64, i.e. the windings. The duration of the pulse can be controlled to alter the dwell time and the amplitude of the current to control the ram force. The pulse control device may be manually triggered by a pedal or triggered by the connector feed mechanism. If the transducer is used, Fig. 5 (not shown), the power supply (66) is connected to a gate (68) controlled by a comparator (72) with a potentiometer. The power supply may be a battery to allow the press to be portable.</p> |
