GB1391991A - Actuating device for switchgear - Google Patents

Abstract

1391991 Retractive switches LA TELEMECANIQUE ELECTRIQUE 17 April 1972 [21 April 1971] 17729/72 Heading H1N An actuating device for a limit switch comprises a housing supporting a rockable shaft 2, two substantially coaxial members 11 and 13 having ends 15 and 16 engaging a flattened portion of shaft 2, resilient means 14 urging the members 11 and 13 against the flattened portion, said members 11 and 13 being relatively movable in an axial direction, whilst being prevented from relative rotation, and a first one 11 of said members being selectively engageable by one or both edges 6 and 8 of the flattened portion, in response to rocking of the shaft 2, in order to transmit the movement of the shaft to the limit switch (operating button 12 only being shown in Fig. 3), and a rotatable adjusting member 7 coupled to at least one of the coaxial members 11 and 13 for turning them and selecting whether said first member 11 is enengageable by only one or both of said edges 6 and 8, said adjusting member 7 being disposed in the housing about the coaxial members 11 and 13 and the resilient means 14 and being turnable from outside the housing via one or more openings 19. As shown, the members 11 and 13 have respective semi-circular portions 15 and 16 which may be cammed by the edges 6 and/or 8 when shaft 2 is rocked by an external lever (3, Fig. 1, not shown). Cylindrical member 7 has a knurled portion 5 accessible via openings 19 and is keyed at 9, 10 to member 11 whereby members 11 and 13 are conjointly rotatable, the flange 15 abutting the ends of portion 16. Member 7 forms a seating for spring 14 and sealingly bears on main housing 1, on which a head part 4 is scoured by screws (23, Fig. 2, not shown). A seal 41 is also provided between member 7 and head 4. When index marks 21 and 22 are aligned as shown, rocking of shaft 2 in respective directions causes edge 6 or 8 to cam member 11 to actuate switch button 12. If portion 5, and hence members 11 and 13, is turned through 90 degrees then rotation of shaft 2 in one direction causes edge 6 (or 8) to actuate the switch but rotation of shaft 2 in the other direction causes the other edge 8 (or 6) to act on member 13 only, and there is no actuation of button 12. Inadvertent rotation of member 7 during actuation of shaft 2 is prevented by the increased friction on surface 20. A ball detent arrangement (Fig. 7, not shown) between member 7 and shaft 2 serves to locate member 7 and also to lock it while shaft 2 is in an actuated condition. An alternative means of rotating member 7 may comprise bevel gearing on its upper edge co-operating with a bevel gear (26, Fig. 6, not shown) coaxial with shaft 2 and having a screwdriver slot (27) accessible externally of head 4.