Patent GB-403801-A (GB)
Title: Improvements in or relating to multi-position electric switches, such as for controlling electric motors
IPC: H01H1/20
Filed: 1932-12-05
Abstract: 403,801. Snap-action switches; motor controllers. IGRANIC ELECTRIC CO., Ltd., 147, Queen Victoria Street, London, and WRIGHT, S. R., 113, London Road, Bedford. Dec. 5, 1932, Nos. 34448/32 and 7619/33. [Classes 38 (iii) and 38 (v).] A multi-pole switch, which may be used as a star-delta starter for a three-phase fourspeed squirrel-cage motor having a low speed and a high speed winding, comprises four rows of fixed contacts and a rotatable insulating plate carrying two movable rows of bridging contacts, one row of bridging contacts being adapted to bridge contacts of two of the fixed rows when the plate is rocked in one direction, while the other row of bridging contacts is adapted to bridge contacts of the other two fixed rows when the plate is rocked in the other direction. In one construction, Figs. 1, 3 and 4, the bridging contacts b<1> ... b<5> are carried by an insulating plate 3 which is slidably and rotatably mounted, by means of a metal member 4 having apertured lugs 4a, 4b, on a fixed shaft 2. Each row of fixed contacts comprises contacts f<1> ... f<8>, and the bridging contacts may be caused to engage either the odd or even contacts of each pair of rows by sliding the plate 3 to the right or to the left, as seen in Fig. 1, and then rotating it ; the movements of the plate being effected by a lever 12 provided with a universal pivot 13. The lever co-operates with lugs 18 on the casing 21, which serve as guides for the longitudinal movements, and prevent the rocking of the plate 3 except when the bridging contacts are in one or other of the positions in which they can engage the fixed contacts. The lug 4b on the rocking member engages rollers 5, 6 in a spring-controlled pivoted frame 7, to give a snap action to the movements of the rocking member. In a modified construction, Figs. 5 and 9, the fixed contacts f<1> .... f<5> are distributed in four rows on two bases 22, 23, and the co-operating bridging contacts are mounted on separate insulating members 25, 26, each of which is connected by links 31, 32 to a pair of push buttons 29, 30, by operating which it can be rocked in either direction about a shaft 24. Lugs 39 on the rocking members cooperate with rollers 40 in spring-controlled plates 41 to give a snap-action to the switching movements. A ball 46, co-operating with recesses in the lugs 39, is adapted to lock either of the rocking members in the "off" position whenever the other is moved into one of its " on " positions. A stop push button 33 is also provided, having a plate 34 adapted to engage both plates 25, 26 ; operation of this button ensures that both plates 25, 26 shall be in their " off " positions. In a modification, Fig. 11, the connecting rods 32 of the plates 25, 26, instead of being connected to separate push buttons, arc connected to cross beams 61 formed with bosses 62 loosely mounted on a shaft 63, which is capable of both longitudinal and rotary movement. Longitudinal movement of the shaft clutches it to one or other of the bosses 62 through one of a pair of cross pins 64, whereupon rotation of the shaft moves one or other of the rows of bridging contacts into engagement with the co-operating fixed contacts. The shaft is operated by a handle 66, which engages a slot 67 in a lug 68 on the casing to ensure correct operation. In all the arrangements each bridging contact is carried by a stirrup 55, Fig. 9, and is formed with a hole 56 engaged by the end of a flanged spring-controlled rod 57, to allow the bridging contact to adjust itself to the fixed contact.