GB1367071A - Control devices - Google Patents

Abstract

1367071 Time switches SMITHS INDUSTRIES Ltd 28 June 1971 [26 March 1970] 14630/70 Heading H1N A control device comprises a time scale, two arrays of selectors, each selector being individually movable manually into a selected one of a plurality of settings, and a respective and predetermined one of each array of selectors being associated at all times with a respective portion of the time scale, and means for performing a control function dependent upon time and on the settings of the selectors associated with the pertinent portion of the time scale. As shown, a programmer for a central heating system comprises a motor 35 deriving, through gearing and planetary stepping means 53, 57 (and 52, 56, Fig. 4, not shown), three parallel cylindrical rollers, of which the centre one 12 carries helical colouring visible through a slot in display panel 10 such that its edge 13 indicates time of day on a scale 11. The outer rollers 25 (and 24, Fig. 2, not shown) each lie beneath a respective row of manually slidable selectors 14 or 17, each selector of each row being associated with a respective two-hour period of the time scale 11. Each roller 25 (24) carries twelve cam-like projections 23 angularly spaced by thirty degrees, and the rollers are stepped at two-hourly intervals to bring the projections 23 successively beneath respective selectors 14 and 17. The selectors have dependent fingers such that a roller 25 (24) is displaced axially if a finger is positioned to be engaged by the associated projection 23. Each selector 17 has three possible positions (see Fig. 1) and two dependent fingers (see Fig. 3). In the "Frostguard" position neither finger lies in the path of a projection 23, but in the "Background" position one finger moves roller 25 axially to the right, and in the "Comfort Heat" position the other finger moves roller 25 to the left. A circumferential slot 30 in roller 25 receives one end of a lever 31, pivoted at 32, such that the axial movements of roller 25 actuate microswitches 33 and 34, respectively, to connect suitable thermostats (not shown) into circuit. Each selector 14 has two possible positions and one dependent finger to cooperate with projections 23 on its roller (24) which is axially movable to operate a microswitch for control of the water heater.