Patent GB-191502697-A (GB)
Title: Improvements in and relating to Electric Maximum Cut-outs.
Inventor: SWAAY GERARDUS JACOBUS VAN
IPC: H01H73/42
Filed: 1915-02-19
Abstract: 2697. Swaay, G. J. van, and Keus, H. I. Feb. 19. Automatic circuit-breakers ; sparking, preventing.-A hand-operated rotary switch, provided with electro-magnetic means for releasing the contact member when the maximum allowable current passes through the switch, comprises a loose operating-handle 10 carrying the operating-member 11 having downturned limbs engaging on opposite sides of stops 12 on a coupling-member consisting of a. rotary disk 9 carrying a diametrically sliding pawl 15, pressed by a spring 17 and having a nose 16, which, when the coupling - member is rotated by the operating-member 11, serves to rotate, through the detent 7, the rotary core 6 of the cut-out electro-magnet. Below the coil 4, the core carries a disk 32 connected to the supporting- plate 3 of the coil by a spiral spring 31, and provided with a projection which engages stops downwardly projecting from the plate 3, whereby the angular movement of the core and the parts it carries is limited. The core carries also at its lower extremity an insulated contact member 22 serving to bridge contact springs in the ' on ' position of the switch. To close the switch, the handle is rotated in the clockwise direction, transmitting motion to the coupling- disk 9. During this motion, a spring detent 19, which in the ' off' position of the switch engages with an opening 20 in the upturned flange 8 of a fixed part of the magnet frame in which the disk 9 rotates, rubs against the inner surface of the flange, until, after a rotation of about three-quarters of a circle, the nose 16 engages with the detent 7 and the core is rotated against the action of the spring 31, carrying with it the contact member 22, through a further quarter of a circle, into the contact-making position. The disk 9 is prevented from rotating back by the spring pawl 19 again engaging the slot 20. The switch may be brought to the ' off' position by a small backward rotation of the handle, one of the limbs of the operating-member engaging a projection 29 on the pawl 15 and lifting the nose 16 free from the core, whereupon the spring 31 returns the contact member to the off ' position. The switch is brought to the ' off ' position automatically, in case of overload, by the attraction to the core of the armature 14 adjustably carried by the pawl, the magnetic field through the armature being concentrated by the provision in the vicinity of the armature of an iron strip 36 extending from the plate 3, which, together with the bottom plate 1, posts 2, and feet 5, is of iron so as to be included in the magnetic circuit. Sufficient stray field exists to act as a magnetic blow-out, and the plates 8, 9, 3 are slotted to reduce eddy currents. The insulating-plate 23 carrying the fixed contacts is secured to the casing by a sealed screw 28, and the terminals of the switch are enclosed in a casing 40 secured to the switch casing by a seal to prevent tampering with the mechanism. The switch is secured to a base-plate 42, secured to a switchboard and having an upstanding projection 43, by passing the projection through a lozengeshaped hole in the bottom of the plate of the switch and rotating the whole switch through 90 degrees.