Instrument for measuring film thickness

Claim 2

An electromagnetic instrument having a main body for measuring a thickness of a surface processing film on a metal, said instrument comprising: (a) a plurality of instruction executing keys provided on a front surface of said main body; (b) a recording apparatus and an indicator enclosed in said main body; (c) a terminal located on said main body for connecting a probe wound by a coil, the probe generating an electromagnetic field in said metal and detecting an electrical signal corresponding to said film thickness in accordance with a distance to said metal when said probe is pressed onto said film coated on said metal; (d) a converting circuit for converting said electrical signal obtained from said probe to a digital value indicative of said film thickness; and (e) an operating circuit for performing processing on said digital value in accordance with instructions inputted from said instruction executing keys; wherein the results of said processing are outputted to said recording apparatus in response to pressing operations of said probe for a predetermined number of measurement times, the predetermined number of measurement times being preliminarily inputted from said instruction executing keys.

Claim 3

An instrument according to claim 1, further comprising an analog power source for supplying power to said converting circuit for only a predetermined time after the depression of the instruction executing keys.

Claim 4

An electromagnetic measuring instrument having a main body for measuring a thickness of a surface processing film on a metal, said instrument comprising: (a) a plurality of instruction executing keys provided on a front surface of said main body; (b) a recording apparatus and an indicator enclosed in said main body; (c) a terminal located on said main body for connecting a probe wound by a coil, said probe generating an electromagnetic field in said metal and detecting an electrical signal corresponding to said film thickness in accordance with a distance to said metal when said probe is pressed onto said film coated on the metal; (d) a converting circuit for converting said electrical signal obtained from said probe to a digital value indicative of the film thickness; (e) an operating circuit for performing processing on said digital value in accordance with instructions inputted from said instruction executing keys, and (f) a holding circuit for holding the digital value, the digital value corresponding to the minimum value of the distances between the probe and the metal; wherein an average of said film thicknesses and its standard deviation are calculated and, together with a number of measurements of the film thickness, outputted to said recording apparatus and to said indicator in response to pressing operations of said probe for a predetermined number of measurement times, said predetermined number of measurement times being preliminarily inputted from said instruction executing keys.

Claim 5

An electromagnetic measuring instrument having a main body for measuring a thickness of a surface processing film on a metal, said instrument comprising: (a) a plurality of instruction executing keys provided on a front surface of said main body; (b) a recording apparatus and an indicator enclosed in said main body; (c) a terminal located on said main body for connecting a probe wound by a coil, said probe generating an electromagnetic field in said metal and detecting an electrical signal corresponding to said film thickness in accordance with a distance to said metal when said probe is pressed onto said film coated on the metal; (d) a converting circuit for converting said electrical signal obtained from said probe to a digital value indicative of the film thickness; (e) an operating circuit for performing processing on said digital value in accordance with instructions inputted from said instruction executing keys, and (f) a holding circuit for holding the digital value, the digital value corresponding to the minimum value of the distances between the probe and the metal; wherein an average of said film thicknesses and its standard deviation are calculated and, together with a number of measurements of the film thickness, outputted to said recording apparatus and to said indicator in response to pressing operations of said probe for a predetermined number of measurement times, said predetermined number of measurement times being preliminarily inputted from said instruction executing keys.