Apparatus and method for detecting printing press web breakage

A method for detecting a position of a web, comprising:

• transmitting periodically a burst of energy for a period of time, the burst of energy being reflected off the web thereby producing an echo signal;
• receiving a first portion of the echo signal by a first transducer;
• receiving a second portion of the echo signal by a second transducer;
• determining a strength of the first portion of the echo signal and a strength of the second portion of the echo signal;
• comparing the strength of the first portion of the echo signal with the strength of the second portion of the echo signal;
• and
• calculating an amount of time elapsed between transmission of the burst of energy and receipt of the portion of the echo signal by the transducer which received the strongest echo signal, thereby detecting whether the web position is acceptable.

A method of minimizing an effect of a web wrinkle or angular distortion during web break detection, comprising:

• transmitting periodically a burst of energy for a period of time, the burst of energy being reflected off the web thereby producing an echo signal;
• receiving a first portion of the echo signal by a first transducer;
• receiving a second portion of the echo signal by a second transducer;
• adding the first portion of the echo signal and the second portion of the echo signal to arrive at a resultant signal;
• and
• analyzing the resultant signal to determine the presence of a web break.

An apparatus for detecting a web break, comprising:

• a first transducer for periodically emitting a burst of energy for a period of time, the burst of energy being reflected off of the web thereby producing an echo signal;
• a second transducer adapted to receive a first portion of the echo signal;
• and
• a third transducer adapted to receive a second portion of the echo signal;
• a comparator in communication with said second transducer and said third transducer for determining whether the first portion of the echo signal or the second portion of the echo signal is stronger, and
• a controller in communication with said communicators which utilizes the stronger portion of the echo signal to detect whether the web is broken.

An apparatus for detecting a position of a web of material traversing a machine for feeding the web, comprising:

• a housing adapted to receive three transducers;
• a first transducer disposed in said housing, adapted to periodically emit a burst of energy for a period of time, the burst of energy being reflected off an object thereby producing an echo signal;
• a second transducer disposed in said housing adjacent to said first transducer, said second transducer adapted to receive a first portion of the echo signal;
• a third transducer disposed in said housing adjacent to said first transducer, said third transducer adapted to receive a second portion of the echo signal;
• and
• an analyzer disposed in communication with said second and third transducers, said analyzer adapted to receive and compare said first and said second portions of the echo signal to determine the stronger portion of the echo signal and the presence of a web break.

An apparatus for detecting a position of a web, comprising:

• a controller;
• an ultrasonic transmitter in communication with the controller for periodically emitting a burst of sonic energy for a period of time in response to a control signal from the controller, the burst of sonic energy having a predetermined amplitude, frequency and phase angle and being reflected off the web thereby producing an echo signal, the echo signal having an amplitude, frequency and phase angle determined by a speed and position of the web;
• a plurality of ultrasonic receivers, each of said plurality of receivers detecting a portion of the echo signal reflected toward each receiver;
• means for determining relative strengths of the portions of the echo signal detected by each of said plurality of receivers;
• and
• means for transmitting to said controller a signal comprising the strongest portion of the echo signal detected by one of said plurality of receivers,
• wherein said controller calculates an amount of time elapsed between transmission of the burst of sonic energy and receipt of the signal comprising the strongest portion of the echo signal detected by one of said plurality of receivers, thereby detecting whether the web position is acceptable.