| 摘要 |
804,550. Automatic temperature control. EYNARD, M. Dec. 9, 1955 [Dec. 11, 1954], No. 35373/55. Class 38 (4). [Also in Group XL (b)] In an automatic control system, variation in the quantity to be controlled displaces an element whose position relative to a member, when in one sense, causes the member to energize means to vary the quantity in one direction and, when in the other sense, causes said means to be de-energized to vary the quantity in the other direction and the member is cyclically oscillated in a direction parallel to the displacement of said element. In the embodiment described, temperature variations control the angular position of a vertical spindle 6 carrying a pointer 1 moving over a dial 2. The pointer carries a rectangular vane 8 which moves in the focal plane of a lens 13 directing light from a lamp 11 and condenser 12 to a photo-cell 14, all located in a horizontal tube 10 having a slot into which the vane 8 penetrates. The tube 10 may be rotated by a knob 20 about an axis 17 coinciding with that of the spindle 6, to set a desired temperature indicated on the dial 2 by the index 33 which carries a stop 34 for the pointer 1. When the temperature reaches the desired value the vane 8 cuts off the light from the cell 14 to de-energize the heat source. In order to reduce hunting in the system, the tube 10 is cyclically oscillated about the axis 17 by a lever 26 operated by a cam 24 driven by an electric motor 23, so that as the temperature approaches the desired value the ratio of energization to de-energization time of the cell 14 is varied by its oscillatory movement relative to the vane 8. |
