Brown, Patrick C.;

Low tension winding apparatus

A plurality of photo sensitive devices arranged in vertical orientation monitors the sag of a loop of optical fiber extending between a feed capstan and a take-up spool. Each detector is connected to a respective switching circuit which, when activated by the presence of the fiber adjacent to its associated detector, generates a unique voltage. The switching circuits are connected to a motor control circuit by a sample and hold circuit which supplies to the motor control circuit a voltage proportional to the voltage generated by the most recently activated switching circuit. The speed of the motor driving the take-up spool is thus adjusted to cause the fiber catenary to return to a predetermined position.

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I claim:

1. An apparatus for automatically controlling the sag depth of a catenary between a feed apparatus that supplies material to the catenary and a take-up apparatus that removes material from the catenary, comprising

a motor for driving said take-up apparatus,

means for illuminating said material in the vicinity of said catenary,

a plurality of photosensitive devices arranged in vertical orientation in the region of the catenary,

a first plurality of voltage generators equal in number to said photosensitive devices, each of said first plurality of voltage generators comprising a switching circuit which is connected to a respective one of said photosensitive devices, and an output resistor, one terminal of which is connected to said switching circuit, the remaining terminal of said output resistor being connected to a power supply by a common output resistor, each said voltage generator being capable of generating a unique voltage which depends upon the vertical position of the photosensitive device connected thereto,

motor speed control means connected to said motor for controlling the rate at which said take-up apparatus removes material from said catenary, and

means for applying to said motor control means a voltage proportional to the voltage generated by the most recently activated voltage generator.

2. The apparatus of claim 1 wherein said last named means comprises a sample and hold circuit, the signal input terminal of which is connected to each of said first plurality of voltage generators, said sample and hold circuit having an enable input terminal and an output terminal, the voltage appearing at said output terminal being dependent upon the voltage at said input teminal at the time that an enable pulse appears at said enable terminal, and pulse generator means connected to said photo sensitive detectors for providing an enable pulse to said sample and hold enable terminal.

3. Apparatus in accordance with claim 2 wherein said pulse generator means comprises a pulse generator, a second plurality of voltage generators equal in number to said number of photosensitive devices, each of said second plurality of voltage generators being connected to a respective one of said photosensitive devices, and means for connecting the outputs of each of said second plurality of voltage generators to the input terminal of said pulse generator.

4. An apparatus for automatically controlling the sag depth of a catenary between a feed apparatus that supplies material to the catenary and a take-up apparatus that removes material from the catenary, comprising

a motor for driving said take-up apparatus,

motor speed control means connected to said motor for controlling the rate at which said take-up apparatus removes material from said catenary,

means for illuminating said material in the vicinity of said catenary,

a plurality of photosensitive devices arranged in a vertically spaced orientation along the distance between the maximum and minimum permisable excursions of the catenary,

a first plurality of switching circuits equal in number to said photosensitive devices, each of said first plurality of switching circuits being connected to a respective one of said photosensitive devices, a plurality of output resistors, one terminal of each of said output resistors being connected to a respective one of said first plurality of switching circuits, the remaining terminals of said output resistors being connected to a power supply by a common output resistor,

a sample and hold circuit, the signal input temrinal of which is connected to the junction between said plurality of output resistors and said common output resistor, said sample and hold circuit having an enable input terminal and having an output terminal which is connected to said motor speed control means, the voltage appearing at said output terminal being dependent upon the voltage at said signal input terminal at the time that an enable pulse appears at said enable terminal, and

pulse generator means connected to said photosensitive detectors for providing an enable pulse to said sample and hold enable terminal.

5. Apparatus in accordance with claim 4 wherein said pulse generator means comprises a pulse generator, a plurality of voltage generators equal in number to said number of photosensitive devices, each of said plurality of voltage generators being connected to a respective one of said photosensitive devices, and means for connecting the outputs of each of said plurality of voltage generators to the input terminal of said pulse generator.