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Dual latching Solenoid With Single Input Terminal

IP.com Disclosure Number: IPCOM000053119D
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Jensen, BH: AUTHOR [+2]

Abstract

The latching relay shown latched in Fig. 1 is selected and latched or not latched by a signal at one input. The electrical path to the magnet latch coil for the latching arm is separated from the input by a capacitor. A short pulse passes the capacitor and drives the latch coil so as to hold back the latch, while a long pulse is blocked by the capacitor and the latch operates.

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Dual latching Solenoid With Single Input Terminal

The latching relay shown latched in Fig. 1 is selected and latched or not latched by a signal at one input. The electrical path to the magnet latch coil for the latching arm is separated from the input by a capacitor. A short pulse passes the capacitor and drives the latch coil so as to hold back the latch, while a long pulse is blocked by the capacitor and the latch operates.

In many applications, it is necessary to vary the length of time a solenoid is engaged. Solenoids designed for intermittent duty, however, cannot be energized for prolonged periods of time without damaging the device. Also, power supplies must be excessively large if many solenoids are required to be simultaneously held down for prolonged periods.

Therefore, to engage the solenoid for prolonged periods, mechanical latches such as that shown in Fig. 1 are employed. Such latches have been operated by a separate input, which increased the circuitry required. The second input is eliminated by the circuit shown in Fig. 2. A long pulse sets the latch while a later, short pulse releases the latch.

The latching solenoid of Fig. 1 may be conventional. It comprises a solenoid coil 1, energization of which pulls down a plunger 3. The top of plunger 3 carries an outwardly extending washer 5. A return spring 7 is located between coil 1 and washer 5.

A pivoted latching or actuator arm 9 is urged by spring 11 toward a position over washer 5. A flat, stop member 12 is mounted on the end of arm 9. A latch coil 13 is effective when energized to magnetically hold arm 9 against coil 13 and out of possible engagement with washer 5. When the mechanism is in the latched position, stop 12 positions arm 9 just over the edge of washer 5.

In the control circuit, shown in Fig. 2, low impedance coil 17 of solenoid 1 is connected between potential source +V and the collector of driver transistor 19. Diode 20 is in parallel with coil 17 and is of a polarity to provide a discharge path when energization is terminated.

High impedance coil 21 of latch magnet 13 is connected in parallel with a capacitor 23 and discharging diode 25. Resistor 26 limits the current through capacitor 23 and capacitor 29...