Sensing device for detecting changes in variable quantities

A remote sensing and data accumulating system for detecting changes in temperature and producing logic signals of different binary significance as inputs to an incremental data accumulator comprising:

• (a) power supply means for supplying said input signals;
• (b) sensing means including a thermal bimetal element having a fixed end and a free end, said free end being movable responsive to changes in said temperature, producing movement in said free end, said movement in one direction indicating an increase in, temperature and in a different direction indicating a decrease in temperature, a movable arm carried connected to said element including magnetic means movable therewith, means for attaching said arm to said element, means for converting movement of said free end into rotational movement of said arm and magnetic means;
• (c) a plurality of electrically groundable magnetic switches disposed in fixed relation to said sensing means and positioned to be serially actuated by said magnetic means to close and actuate an electrical circuit, the closing of said circuit providing a binary signal of one significance, and said switches serially actuated by said magnetic means to open said circuit, the opening of said circuit providing a binary signal of a significance different than said closing signal significance;
• (d) circuit means electrically coupling said groundable switches and the input signals from said power supply means for distributing said binary signals;
• and,
• (e) logic circuit means connected to said groundable switches in binary input signal receiving relation including a plurality of multiple input logic gates for providing selected binary output signals which are representative in a sequence corresponding to the direction of increase or decrease in said temperature, each of said gates producing a single binary output which may be either of first or second binary significance, said output being of first binary significance only when one of said input signals is of one of said first and second binary significances and all of said other input signals are the other of said first and second binary significances said gates arranged in said circuit means in a sequence of a first to a last gate in order, said first gate of said sequence having a grounded input and at least one additional input connected to said power supply means through a load resistor for producing a binary input signal of said first binary significance, said remaining gates in said sequence each having an input connected to said additional input of a gate preceding it and an additional input connected to said power supply means through a load resistor and to said groundable switches, whereby said input is held at a value of first binary significance until grounded and said value of first binary significance is changed to a value of second binary significance.