Control means for operating a pilot valve or relay controlling a source of power for effecting a cyclic operation in a plant or installation

摘要

702,327. Time switches. HUMPHREYS & GLASGOW, Ltd., and MITCHAM, G. E. May 30. 1951 [July 19, 1950], No. 18081/50. Class 38(5) [Also in Group XXIX] Control means for operating a pilot valve or electrical relay 32, Fig. 1, controlling the source of power for effecting a cyclic operation in a plant or installation, comprises a beam 17 for operating the valve or relay 32 and urged by a spring 22 to contact the profiles of rotating cams 25, 26, movement of either end of the beam towards the axis of its adjacent cam, permitted by depressions 34SP1/SP, 35SP1/SP, operating the valve or relay in one direction or the other through links 30, 31, bell-cranks 28, 29, a wheel 36, Fig. 2, a member 15 slidable on bars 37, and a rod 38. When the plant operation initiated by actuation of the valve or relay is completed, the beam is moved out of the cam depression by a device 40 to which power is automatically supplied, and which acts through a rod 39, a member 16 slidable on the bars 37, and a wheel 56 which engages the appropriate belt-crank. A projection 27, Fig. 3, is formed on each cam and cooperates with a bar 41 slidable in the beam 17 and engaging a trip lever 42 which, when turned, triggers mechanism which shuts down the plant. This occurs when the projection 27 engages the bar 41 as would happen if the plant operation is not successfully completed or if for any other reason the device 40 fails to operate. The bellcranks may be made inoperative by turning a cam 51 through 90‹ on its shaft 52 and the valve or relay may then be hand operated by a lever 53. Two or more control means may be combined to operate in sequence, in which case all the cams 25, 26 are mounted on common shafts 18, 19, respectively, the cams 51 are all on a common shaft 52 for rendering all the control means inoperative simultaneously and interlocking means is provided to prevent operation out of a desired sequence for both automatic and manual operation. Clockwise rotation of a cam 57 raises the beam out of contact with the cams so that each control means may be rendered inoperative individually. The cams are driven from a driving pinion 45 through a gear 46 which engages spur wheels 47, 48 on the cam shafts 18, 19 respectively. In a modification, latches are pivoted on bar 41 for co-operation with the projections 27.