GB689257A - Improvements relating to electrical change-over switches - Google Patents

Abstract

689,257. Snap-action switches. MONNHAMPS, A. Aug. 9, 1950 [Aug. 9, 1949], No. 19837/50. Class 38 (v) A switch adapted for the rapid and alternate connection of a conductor 1 to one of two conductors 2, 2a, comprises two banks of fixed and movable contacts, Fig. 4, each having a main contact 3, or 3a and auxiliary contacts 4 .. 8 or 4a .. 8a which are in parallel therewith and in series with a contact impedance, such as an inductance 9. The movable contacts, four being shown in Fig. 1 at 40, 41, 40a, 41a, are resiliently mounted on rods 20, 20a between stops 32, 33, and cooperate with fixed contacts 47, 48, 47a, 48a, the auxiliary contacts having series blow-out coils 49 formed therein. In the closed position, the stops 33 are spaced from their corresponding movable contacts by increasingly large gaps x, y so that the contacts are engaged and disengaged progressively on rectilinear movement of the rods. The latter are linked by a rocker arm 23 co-operating with a cam 28 on a shaft 29, so that the rods move simultaneously in opposite directions to operate the two banks of contacts simultaneously, i.e. when a contact in one bank opens, the corresponding contact in the other bank closes. The shaft 29 is rotated to-and-fro through a limited angle by a mechanism comprising an arm 52 loose thereon and connected to an operating arm 54, a slotted arm 55 fixed to the shaft, and an arm 58 loose on a spindle 59 and having a pin 57 engaging in the slot 56, the parts being held in the extreme positions e.g. that shown, by a spring 65 connected to the pin 57 and to the outer end 53 of the arm 52. Rotation of the arm 52 by reciprocating movement of member 54, eventually moves the spring across the spindle 59 so as to pivot the arm 58 and thus the arm 55 and shaft 29. A toothed segment 62 fixed to arm 52 rotates a pinion 61 having a pin 63 adapted to engage the arm 58 to provide positive actuation if the spring fails.