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US 4,166,246 AGranted
Digital control system for automatically compensating for conveyer movement changes
AssigneeNordson Corporation
InventorTimothy S. Matt
Life of this patent
Estimating the term…
Abstract
A digital control system is disclosed for activating a responsive device, such as a dispenser, at a preselected time after an initiating event, for a predetermined duration period. The system can be used for example in the packaging industry to apply adhesive at precise locations on a box moving on a conveyor. The system automaticaly compensates for conveyor speed and for the pull-in time and/or drop-out time of the responsive device.
Claims21
A controller to activate a responsive device at a preselected time after initiating event, for use with articles moving on a conveyor, comprising:
- a distance sensing circuitry adaptable to provide output pulses for preselected increments of conveyor travel;
- triggering means adaptable to be responsive to an initiating event, to provide an output signal upon the occurrence of said initiating event;
- at least a first counter for said pulses from said distance sensing circuitry, said counter being settable to a preselected count within a range, the counter being controllable to count in response to the output signal of said triggering means, and which provides an output signal at a predetermined count;
- and
- an update control circuit responsive to said counter, and said triggering means to be effective to set the counter to said preselected count prior to the occurrence of said initiating event;
- wherein the output signal of said counter is adaptable to control the activation of said responsive device.
3 more elements
A control circuit to activate a responsive device for use in conjunction with a conveyor comprising:
- a sensor means to detect articles moving on the conveyor at a first location and to provide an output signal thereupon;
- pulse tachometer means to provide output pulse signals for each predetermined increment of conveyor travel;
- a triggerable timer means operative to provide an output signal for a time duration corresponding to delay characteristics of said responsive device;
- a pulse generating means to provide output pulses for each increment of conveyor travel, the pulses from said pulse generating means being out of phase with said pulses from said pulse tachometer means;
- a counter means automatically settable to a count representative of the distance between said sensor means at said first location and a responsive device at a second location plus the distance from the triggering edge of said article to the point at which said responsive device is to operate on said article, said counter being operative to count pulses from said pulse tachometer means and from said pulse generating means and being operative to provide a carry-out signal at a count of zero;
- update circuit means to periodically trigger said timer means and sets said counter to said representative count, except while said counter is counting to said carry-out signal;
- control means to enable said counter to count pulses from said pulse generating means only during said output signal from said timer means, and count pulses from said pulse tachometer means in response to the signal from said sensor means at least until a carry-out signal is generated by said counter means, and
- means responsive to said carry-out signal to activate said responsive device.
5 more elements
A method of controlling a responsive device to treat articles moving on a conveyor comprising the steps of:
- sensing articles moving on said conveyor at a first location and providing an output signal thereupon;
- generating first and second pulses out of phase with each other for each predetermined increment of conveyor travel;
- setting a counter to a count representative of the number of increments of conveyor travel between said first location and the location of said article where said responsive device is to operate on said article;
- counting first pulses down from said set representative count to zero in response to sensing an article traveling on said conveyor, and generating a carry-out signal at zero count;
- periodically, except while said counter is counting to said carry-out signal, triggering a timer means operative to provide an output signal for a time duration corresponding to delay characteristics of said responsive device and setting said counter to said representative count;
- counting said second pulses with said counter only while providing said output signal from said timer;
- and
- activating said responsive device in response to said carry-out signal;
- counting said second pulses with said counter only while providing said output signal from said timer;
- and
- activating said responsive device in response to said carry-out signal.
8 more elements
A control circuit for a responsive device used to treat articles moving on a conveyor comprising:
- a sensor located upstream from said responsive device and effective to provide an output in response to articles moving therepast on said conveyor;
- means to provide at least first pulses representing incremental conveyor travel;
- a counter automatically settable to a first count and controllable to count said first pulses from said first count to a second count, and to provide an output signal effective to control operation of said responsive device at said second count, the difference between said first count and said second count representing conveyor travel between the time said sensor provides an output signal and the time the article is to be treated;
- periodic update means to periodically, except while said counter is counting from said first count to said second count, cause said counter to be adjusted in count by a count representative of current conveyor travel in the time required for said responsive device to operate after receiving a control signal;
- and
- control circuitry means to sequence the response of said counter to said sensor signal and said periodic update means.
3 more elements
Dependencies are inferred from the claim text.