Abstract A web width monitor which includes a long-line infrared light source located on one side of a running web and parallel to the width dimension to be monitored, a primary photodetector arranged on the opposite side of the web, and a motion detector and pulse former arranged to provide electrical control signals related to length of web motion. A reference photodetector is connected in series with the primary photodetector device and arranged to minimize signal drift due to ambient and circuit operating temperature changes. A first subcircuit linearizes the width indicating photo signal and impresses it on a meter and recorder. This first subcircuit is also connected to a signal integrator circuit arranged to provide counter signal pulses at a recurring rate proportional to tow width. These signals are impressed on a decade counter for a timed interval regulated by a timer device. This provides a readout of integrated average tow width over the time interval. The first subcircuit is, in addition, arranged to furnish analog width signals to a width level detector circuit which is arranged to gate a counter power circuit which in turn is connected to the web motion detector. The counter power circuit is separately gated to two decade counters, one arranged to indicate web length which has greater than a specified width and the other length of web having less than a predetermined width. Each counter is connected to a trip and hold alarm circuit which is actuated when that counter reaches a preselected level.
An apparatus for monitoring variations in width of a continuously moving web and for furnishing indications of length of web having widths above or below a preselected value and average web width for a timed interval comprising: a source of light positioned on one side of said web; a photodetector positioned on the other side of the web to receive light from said source as modified by the width of the web and to produce a first signal the amplitude of which varies in accordance with the width of the web; a motion detector coupled to the web for producing a second signal related to length of web motion; width level circuit means connected electrically to said photodetector and actuated by said first signal for producing an output signal corresponding to variations in web width above or below preselected values; means electrically connected to said motion detector and said width level circuit and actuated by said output signal and said second signal for indicating the length of web having a width above or below the preselected values; integrator circuit means connected electrically to said photodetector and actuated by said first signal, said integrator circuit having components for providing pulses at a rate proportional to the width of the web; a counter connected to said integrator circuit means and actuated by said pulses; and means for simultaneously energizing the integrator circuit means and the counter for a timed interval.
Claim 2
Independent Claim
238 words
An apparatus for monitoring variations in width of a continuously moving web and for furnishing indications of length of web having widths above or below a preselected value and average web width for a timed interval comprising: a source of light positioned on one side of said web; a photodetector positioned on the other side of the web to receive light from said source as modified by the width of the web and to produce a first signal the amplitude of which varies in accordance with the width of the web; a motion detector coupled to the web for producing a second signal related to length of web motion; width level circuit means connected electrically to said photodetector and actuated by said first signal for producing an output signal corresponding to variations in web width above or below preselected values; means electrically connected to said motion detector and said width level circuit and actuated by said output signal and said second signal for indicating the length of web having a width above or below the preselected values; integrator circuit means connected electrically to said photodetector and actuated by said first signal, said integrator circuit having components for providing pulses at a rate proportional to the width of the web; a counter connected to said integrator circuit means and actuated by said pulses; and means for simultaneously energizing the integrator circuit means and the counter for a timed interval.
Claim 3
Dependent Claim
79 words
The apparatus of as defined in claim 1, said components comprising: a constant current source connected electrically to said photodetector, said source being modulated by said first signal; a capacitor electricaLly connected in parallel with said source, said capacitor being charged by said current source, and means connected in parallel with said capacitor for discharging said capacitor whenever its charge reaches a preset level and for generating repetitive switch actuating signals at a repetition rate proportional to web width.