| 摘要 |
756,352. Photo-electric control system. MICRO BALANCING, Inc..June 30, 1953 [Aug. 21, 1952], No. 18050/53. Class 40 (3). [Also in Group XXXVII] In a street lighting control system a photocell responsive to ambient illumination operates a thermostat to control the light. As shown, the photo-cell 1 feeds an amplifier 2 which energizes the heating coil of a thermostatic element having bimetallic arms 5, 6. Arm 5 deforms and contacts a fixed stop 13 thereby rocking the element as a whole about a pivot 7 until the other arm 6 opens a switch 10 in the light circuit. If ambient temperature changes, both arms deform but remain parallel so that the element rocks about pivot 7 but switch 10 is not operated. Incident light causes A.C. fed photo-cell 1 in series with resistors 25, 27 and 29 to conduct thereby increasing the conductivity of A.C.-fed triode 20. The voltage developed across the cathode load triggers a glow discharge tube 21 in the circuit of which is heating coil 3 of the bimetallic element. The Specification states that the heat from the discharge tube itself may be used to heat this element. The bimetallic element may be helical so that if heat is applied to one end the helix rotates but changes of ambient temperature merely alter the spacing of the turns. |
