GB1393386A - Electromagnetically operated solid state circuit controlled timing device - Google Patents

Abstract

1393386 Magnetically held switches SQUARE D CO 14 June 1972 [17 June 1971] 27785/72 Heading H1N [Also in Divisions G3 and H3] In an arrangement for timed control of electric circuits a switch 18 is actuated by first electromagnet 14, 26, 28, 30 with a time delay introduced by a permanent magnet holding device 20 and determined by a timing circuit (Fig. 10, not shown) which pulses a second electromagnet the flux of which opposes that of the permanent magnet, to release the holding device. The switch may be single pole double throw snap acting type. Thus the switch will be actuated from a first position to a second position a predetermined interval after the first electromagnet is energized (TDE mode) or alternatively will remain in its actuated second position for a predetermined interval after the first electromagnet is de-energized, (TDD mode). The first electromagnet coil 28 has a secondary winding with terminals 36 connected to the timing circuit Fig. 10. When A.C. is applied to the coil 28 it is energized to cause armature 30 to move upwards into engagement with magnetic core part 26, and produces an output from secondary terminals 36. Movement of the armature 30 causes an actuator 16 and a cam 25 (detailed Fig. 7, not shown) to move upwardly. A cam surface 104 of the cam 25 engages a downwardly facing surface 113 of a lever 70 (detailed Fig. 6, not shown) causing the lever to rotate counter-clockwise to its actuated position (illustrated Fig. 3, not shown). Movement of lever 70 causes an armature 86 of the holding device, to rotate counter clockwise to a position whereat its portion 98 engages a pole face 92 and causes a lever 122 (detailed Fig. 6, not shown) to rotate counter clockwise to move a plunger 130 against a spring bias, so as to actuate the snap switch 18. When the first electromagnet 14 is de-energized the armature 30 and actuator 16 will move downwardly to deactuated position. The lever 70 however, is prevented from moving since permanent magnet 76 holds the armature 86 which is coupled to the lever 70. Thus levers 70, 122, plunger 130 and switch 18 are held in actuated positions. The magnet coil 78 is energized briefly by circuit Fig. 10, a predetermined interval after coil 28 is de-energized, thereby releasing the armature and allowing the levers and switch to return to their deactuated positions, assisted by the spring loaded plunger. The armature may be used manually. Similarly the switch may be actuated a predetermined interval after energization of coil 28.