Web break detector

Claim 1

A system for monitoring a moving web for breaks in the web, said system comprising wA. a light source, B. a clock for generating a train of pulses, said clock being connected to the light source so that the clock pulses intermittently excite the light source, C. a light sensor responsive to the light from the light source so as to generate sense pulses in response to light from the source, C. a light sensor responsive to the light from the light source so as to generate sense pulses in response to light from the source, D. means for positioning the light source and sensor so that they are aimed at a selected point in the path of a moving web, E. a monitor circuit responsive to the sense pulses for generating an alarm signal, and F. a gate in circuit between the sensor and the monitor circuit, said gate being activated by the coincidence of clock pulses and sense pulses so that the monitor circuit generates an alarm signal depending upon the presence or absence of web at the selected point in the web path, said positioning means being arranged to mount the light source and light sensor in a position close to the web path and on opposite sides of a center line perpendicular to the web path each at an angle relative to the center line such that the system is sensitive to a slack web condition at the selected poinnt, but insensitive to a fluttering web at the selected point.

Claim 2

A system for monitoring a moving web for breaks in the web, said system comprising wA. a light source, B. a clock for generating a train of pulses, said clock being connected to the light source so that the clock pulses intermittently excite the light source, C. a light sensor responsive to the light from the light source so as to generate sense pulses in response to light from the source, C. a light sensor responsive to the light from the light source so as to generate sense pulses in response to light from the source, D. means for positioning the light source and sensor so that they are aimed at a selected point in the path of a moving web, E. a monitor circuit responsive to the sense pulses for generating an alarm signal, and F. a gate in circuit between the sensor and the monitor circuit, said gate being activated by the coincidence of clock pulses and sense pulses so that the monitor circuit generates an alarm signal depending upon the presence or absence of web at the selected point in the web path, said positioning means being arranged to mount the light source and light sensor in a position close to the web path and on opposite sides of a center line perpendicular to the web path each at an angle relative to the center line such that the system is sensitive to a slack web condition at the selected poinnt, but insensitive to a fluttering web at the selected point.

Claim 8

A system for monitoring a moving web for breaks in the web, said system comprising A. a light source directed on the web to be monitored, B. a clock connected to the light source, said clock generating a train of pulses for intermittently exciting the light source, C. a light sensor positioned so as to receive the reflections of the source light from the web and generate sense pulses in response thereto, D. a comparator circuit connected to receive the sense pulses and compare the level thereof to a predetermined level, said comparator circuit generating an output pulse each time a sense pulse exceeds said predetermined level, E. a monitoring circuit responsive to pulses from the comparator for generating an alarm signal in the absence of a selected number of comparator output pulses, and F. a gate connected between the monitoring circuit and the comparator circuit, said gate being activated by the coincidence of the clock pulses and the comparator output pulses so that the monitor circuit receives output pulses from the comparator and does not generate an alarm signal as long as web is present between the light source and the light sensor.

Claim 9

A system for monitoring a moving web for breaks in the web, said system comprising A. a light source directed on the web to be monitored, B. a clock connected to the light source, said clock generating a train of pulses for intermittently exciting the light source, C. a light sensor positioned so as to receive the reflections of the source light from the web and generate sense pulses in response thereto, D. a comparator circuit connected to receive the sense pulses and compare the level thereof to a predetermined level, said comparator circuit generating an output pulse each time a sense pulse exceeds said predetermined level, E. a monitoring circuit responsive to pulses from the comparator for generating an alarm signal in the absence of a selected number of comparator output pulses, and F. a gate connected between the monitoring circuit and the comparator circuit, said gate being activated by the coincidence of the clock pulses and the comparator output pulses so that the monitor circuit receives output pulses from the comparator and does not generate an alarm signal as long as web is present between the light source and the light sensor.

Claim 16

A system for monitoring a moving web for breaks in the web, said system comprising A. a light source, B. a clock for generating a train of pulses, said clock being connected to the light source so that the clock pulses intermittently excite the light source, C. a light sensor responsive to the light from the light source so as to generate sense pulses in response to light from the source, D. means for positioning the light source and sensor so that they are aimed at a selected point in the path of a moving web, E. a monitor circuit responsive to the sense pulses for generating an alarm signal, and F. a gate in circuit between the sensor and the monitor circuit, said gate being activated by the coincidence of clock pulses and sense pulses so that the monitor circuit generates an alarm signal depending upon the presence or absence of web at the selected point in the web path, said positioning means being arranged to mount the light source and light sensor in a position close to the web path and on opposite sides of a center line perpendicular to the web path each at an angle relative to the center line such that the system is sensitive to a slack web condition at the selected point, but insensitive to a fluttering web at the selected point.

Claim 17

A system for monitoring a moving web for breaks in the web, said system comprising A. a light source, B. a clock for generating a train of pulses, said clock being connected to the light source so that the clock pulses intermittently excite the light source, C. a light sensor responsive to the light from the light source so as to generate sense pulses in response to light from the source, D. means for positioning the light source and sensor so that they are aimed at a selected point in the path of a moving web, E. a monitor circuit responsive to the sense pulses for generating an alarm signal, and F. a gate in circuit between the sensor and the monitor circuit, said gate being activated by the coincidence of clock pulses and sense pulses so that the monitor circuit generates an alarm signal depending upon the presence or absence of web at the selected point in the web path, said positioning means being arranged to mount the light source and light sensor in a position close to the web path and on opposite sides of a center line perpendicular to the web path each at an angle relative to the center line such that the system is sensitive to a slack web condition at the selected point, but insensitive to a fluttering web at the selected point.