GB926697A - Improvements in electric switches - Google Patents

Abstract

926,697. Electrically - tripped switches. LICENTIA PATENT - VERWALTUNGSG.m.b.H. March 16, 1961 [March 16, 1960; April 14, 1960; Sept. 23, 1960], No. 9736/61. Addition to 926,200. Class 38 (5). A switch generally similar in construction to that of the parent Specification has its T-shaped base assembly comprised of two parts, each of generally L-shaped cross-section and arranged back-to-back .to form the partition and base, Fig. 10 (not shown). The partition may have cavities to accommodate part of the switch mechanism which may be further supported by abutments formed on the groove Fig. 11 (not shown). In a modification, the L-shaped parts 1, 2 have recesses forming a chamber 7 containing the operating mechanism which comprises a rocking lever 9 having a slot engageable by the pin 12 of a pivoted dolly lever 11, one end of the lever 9 being hinged to a slide 13 and the other end being engageable with the pawl arm 15 of a bell-crank lever pivoted at 14. The horizontal arm of this lever has a projection 37 and is engageable with a rod 28 operable by the plunger 27 of a trip coil 8, and with a rod 29 operable through an adjusting screw 41 by a bi-metal strip 26. The slide 13 acts on the central limb 17 of a pivoted E-shaped bridge, whose outer limbs extend into the arc chambers 5, 6 and carry contacts cooperating with fixed contacts 21 biased by springs 25, a spring 18 acting on the bridge in the contact opening direction. The parts 1, 2 have projections 32, 33 carrying arc-quenching plates 31, the end plate of each stack being formed by one arm of a U-shaped metal member 34. The lever 11, the bell-crank lever and the plunger 27 have return springs 38, 39, 40. To close the switch the lever 11 is rotated clockwise firstly engaging lever 9 with the pawl 15 and then rotating the lever 9 to close the contacts, movement of the pin 12 in the slot latching the lever 11 in the " on " position. Upon short-circuit plunger 27 moves the bellcrank lever clockwise to unlatch members 9, 15, the projection 37 engaging the limb 17 to separate the contacts and members 9, 13 being restored by the spring 18. Upon overload the strip 26 moves the bell-crank lever to unlatch members 9, 15 and allow the spring 18 to open the contacts. In a further modification, Fig. 7 (not shown), the chamber containing the operating mechanism is completely closed off from the arc chambers. In another modification, Figs. 8 and 9 (not shown), the trip coil is housed in a chamber situated below the switch base and the partition engages a groove in the cover for securing thereto. Each arc chamber contains a rectilinearly-movable contact bridging a pair of fixed contacts. Parts 1 and 2 may be moulded by pressing perpendicularly to their plane of division, ie. in the direction of the least dimension, and may be secured together or held in place by the cover.