초록 ▼

A measuring device for measuring the value represented by an indication on a graph, chart, map, or the like, having a calibration scale. The measuring device can accommodate any calibration scale over a wide range. The measuring device includes a first member, having a first reference indication on

A measuring device for measuring the value represented by an indication on a graph, chart, map, or the like, having a calibration scale. The measuring device can accommodate any calibration scale over a wide range. The measuring device includes a first member, having a first reference indication on it, and a second member, having a second reference indication on it. The second member is movable with respect to the first member between a closed position, in which the two reference indications are adjacent each other, and an extended position, in which the two reference indications are separated. A first voltage signal, indicative of the separation of the first and second members, is applied to a ratiometric digital voltmeter which also receives as an input a second voltage signal determined by the setting of a manually adjustable control. The ratiometric digital voltmeter provides an output signal that is indicative of the ratio of its two input voltages, and this output is indicated on a digital display unit. In use, the two reference indications are placed at the two ends of the calibration scale indication of the graph, chart, map, or other such paper, to apply to the ratiometric digital voltmeter a first voltage signal indicative of that calibration scale indication, and the manually adjustable control is adjusted until the calibration value represented by that calibration scale indication is shown on the digital display unit. The two reference indications are then placed at the two ends of the indication to be measured, and the ratiometric voltmeter output, shown on the digital display unit, then represents that measured value.

대표청구항 ▼

A measuring device comprising: a first member having a first reference indication; a second member having a second reference indication and movable with respect to said first member between a closed position, in which said first and second reference indications are adjacent each other, and an extend

A measuring device comprising: a first member having a first reference indication; a second member having a second reference indication and movable with respect to said first member between a closed position, in which said first and second reference indications are adjacent each other, and an extended position, in which said first and second reference indications are separated; a first rheostat adapted for connection across a voltage source and having a control permitting manual adjustment of the setting thereof for providing a calibration voltage signal indicative of the setting thereof; a second rheostat including a resistance element connected to one of said first or second members and a moving contact connected to the other of said first or second members to provide a second voltage signal indicative of the position of the second member with respect to the first member; a ratiometric digital voltmeter having a first input coupled to said first rheostat and a second input coupled to said second rheostat for providing a digital signal indicative of the ratio of the second voltage signal to the first voltage signal; and display means coupled to said ratiometric digital voltmeter for displaying the digital signal.