GB1358730A - Time switches - Google Patents

Abstract

1358730 Time switches SANGAMO WESTONLtd 22 Sept 1972 [22 Sept 1971] 44237/71 Heading H1N A time switch having a timing dial 10 with adjustable ON and OFF operating tappets 14, 16, is provided with an omit disc 22 capable of receiving one or more detachable omit tappets 54 around its periphery, linkage means 38, 46 being arranged to be entrained by one only of said operating tappets 14 or 16 to step said omit disc 22, and a pair of omit arms 56 (58, Fig. 2, not shown) respectively associated with the ON and OFF switching functions are positioned adjacent to the omit disc 22 such that one or other of the arms is engageable by each fitted omit tappet 54, whereby stepping of the omit disc 22 is effective, depending upon the omit tappets carried by the disc, to inhibit the switching function of either the said one or the other operating tappet 14 or 16 until the next stepping of the omit disc 22. As shown, dial 10 rotates anti-clockwise and tappets 14, 16 act on respective levers 18, 20, which carry pawls not shown, to actuate contacts not shown. Omit arms 56, (58), when moved by a tappet 54 to a position such as 56a, render the appropriate pawl inoperative such that the engagement of the relevant tappet 14 or 16 with its lever 18 or 20 has no effect. The arms 56, (58) lie on each side of the plane of the omit disc 22, and clip-on tappets 54 have radially prominent tongues (55, Fig. 2, not shown) extending across not more than half the axial width of the tappet such that they can act on lever 56 or 58 according to their orientation when fitted. The disc 22 is stepped by an integral ratchet wheel 28 when the nose 39 of link 38 is moved by tappet 14 engaging a nose 52 on link 46. The disc 22 is mounted on a shaft (26) held in slots 30 in front and rear bearing plates, under bias of a detent arm 36, and can be readily exchanged for a twopositions-per-day disc (Fig. 3, not shown) if the timing dial has two ON and two OFF tappets, or a three-positions-per-day disc (Fig. 4, not shown) when three ON and three OFF tappets are provided on dial 10. In the latter case the ratchet wheel 28 has a larger diameter so that the movement of link 38 produces the requisite smaller angular step.