Thermal measuring and testing – Thermal testing of a nonthermal quantity
Reexamination Certificate
2002-07-10
2004-04-20
Gutierrez, Diego (Department: 2859)
Thermal measuring and testing
Thermal testing of a nonthermal quantity
C374S148000, C374S185000, C073S204240, C198S502100
Reexamination Certificate
active
06722781
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a method and apparatus for assessing the motion of flat objects moved through a channel. In particular, the invention is related to such a method and apparatus where the measurement is based on the output of at least one anemometric sensor affected by the airflow associated with movement of the flat object.
BACKGROUND OF THE INVENTION
Various conventional motion-checking methods are known in the art, e.g., methods of using electromechanical sensors (U.S. Pat. No. 6,220,103; U.S. Pat. No. 6,192,285; U.S. Pat. No. 5,814,778; U.S. Pat. No. 5,324,898, U.S. Pat. No. 4,687,928, etc.), ultrasound methods (U.S. Pat. No. 6,331,964; U.S. Pat. No. 4,414,591, etc.), methods of using piezoelectric sensors (U.S. Pat. No. 5400,012; U.S. Pat. No. 5,258,743 etc.,) capacitive and charge sensitive methods (U.S. Pat. No. 5,391,859, U.S. Pat. No. 4,833,281 etc.), methods of using microwave technique (U.S. Pat. No. 6,333,691, U.S. Pat. No. 4,981,158 etc.), methods of using pyroelectric sensors (U.S. Pat. No. 6,215,399; U.S. Pat. No. 6,163,025; U.S. Pat. No. 4,943,712 etc.), methods of using optical images (U.S. Pat. No. 6,219,455; U.S. Pat. No. 5,824,916; U.S. Pat. No. 5,212,379; U.S. Pat. No. 4,896,966; U.S. Pat. No. 4,099,886 etc.), and its computer processing (U.S. Pat. No. 6,317,136, U.S. Pat. No. 6,188,798; U.S. Pat. No. 5,568,203; U.S. Pat. No. 4,906,846 etc.), methods of using coherent lighting (U.S. Pat. No. 5,212,379; U.S. Pat. No. 4,334,777 etc.). It is difficult or expensive to use any of these methods for evaluating the movement of currency papers due to the changing,size, thickness, material, surface appearance, configuration and deterioration characteristics of currency paper. Currency paper, when moved through a channel, also has a significant vibration making the assessment more difficult.
U.S. Pat. No. 6,203,194 to Beerwerth et al., describes the thin film multipair thermopile sensor for multipurpose motion detector which is provided with diaphragms and/or focusing elements arranged so that a moving object focused images passes by the hot and cold junctions of the sensor element alternatively, causing a corresponding sensor output signal to be generated. However, this method needs a fixed lighting of testing objects and an extensive optical set for focusing a large object to the thermopile sensor.
It is known to include in paper transport arrangement, a paper jam detector (U.S. Pat. No. 4,734,744 and U.S. Pat. No. 4,203,589). An expensive array of optical sensors check the passageway for the absence of a paper sheet in the specified place at the specified point in time. However, all these detectors have a significant time delay between an actual paper jam and the detector identifying a paper jam.
Airflow detection using a previously heated anemometer is known (U.S. Pat. No. 6,101,872; U.S. Pat. No. 5,827,960; U.S. Pat. No. 5,710,380; U.S. Pat. No. 5,629,481; U.S. Pat. No. 5,558,099; U.S. Pat. No. 5,394,883; U.S. Pat. No. 5,272,915; U.S. Pat. No. 5,263,370; U.S. Pat. No. 5,094,105; U.S. Pat. No. 5,081,866; U.S. Pat. No. 4,884,215). However, the prior art detectors are complicated and designed for relative slow movement and cannot detect in real time, short weak airflow vibration typical of airflow vibration waves from leading and trailing edges of a banknote.
The present invention provides a contactless method of sensing the motion or unexpected stoppage of currency papers with arbitrary size, thickness and deterioration, by measurement of the airflow movement around moving currency paper or air movement associated with the unexpected stoppage thereof.
The present invention provides an apparatus for checking the currency paper motion including at least one sensor for real-time measurement of the speed changes of the airflow associated with the motion or unexpected stoppage of currency paper.
In a preferred aspect of the invention, the apparatus contains at least two airflow sensors for measuring the instantaneous speed changes of the airflow associated with the currency paper.
In a further aspect of the invention, the apparatus contains a line of airflow sensors and the signals thereof are processed to provide real-time position information of currency paper edges.
In an aspect of the invention, the apparatus contains a two-dimensional matrix of airflow sensors for detecting the real-time position of currency paper in a transporting channel.
According to yet a further aspect of the invention, a low cost failsafe compact planar heat-loss airflow sensor for sensing changes in airflow is provided.
A preferred motion checking apparatus, according to the present invention, is inexpensive and easily incorporated into banknote validators.
The real-time information about currency paper motion is used to control currency transportation and to reduce paper jams in validity checking machines, including validators, banknote dispensers, and automated payment systems for receiving and dispensing of banknotes.
SUMMARY OF THE INVENTION
The present invention provides an improved contactless method and apparatus for rapid and inexpensive motion checking of flat objects by detecting of air turbulence around the object especially adjacent its front and back edges. The objects need not be identical in surface appearance, configuration and deterioration. The objects preferably may be of substantially any size or thickness and need not be less than some maximum size or within some narrow range of thickness.
A contactless method of checking the motion or unexpected stoppage of flat objects according to the present invention includes measuring the instantaneous cooling rate of a previously heated thin sensor wire or small bead thermistor located in the airflow associated with the moving test object.
All objects that move through an atmosphere cause a corresponding tight-fitting air movement. Thin end moving flat objects produce front and back shock waves that are distinguishable from the almost uniform airflow associated with the middle portion of the object. Unexpected stoppage of a flat object causes vibrations of airflow, especially when objects are thin like currency papers. These shock and vibration airwaves produce a change in airflow which cools the heated thin metal wire with a corresponding decrease of its resistance &Dgr;R. The corresponding voltage drop on this wire &Dgr;U=I×&Dgr;R where I is a current through wire. When NTC thermistor is used one can get the corresponding voltage increase. Alternating component of this signal is practically independent of any surrounding quasi-steady airflow and temperature, whereby the voltage drop is indicative of the motion status of the object.
In accordance with the present invention, an apparatus for motion checking of flat object includes at least one heat-loss sensor located parallel to one side of a testing object with the sensor connected to a steady current source and amplifier which forms a signal proportional to the instantaneous rate of sensor cooling.
Further in accordance with preferred embodiment of the present invention, the heat-loss sensor is connected to an alternating voltage amplifier through derivation circuit. The preferred time constants of amplifier and derivation circuit are similar to typical flat object motion time along the wire or to flat object oscillation period under unexpected stoppage.
Further in accordance with a preferred embodiment of the present invention, the said sensor includes a series of heat-loss elements connected sequentially and positioned at equal distances from one another and parallel to frontal edge of a testing object. To get the optimal time resolution of motion process optimal distance d between adjacent elements is less than d=
3
&tgr;×&ugr;, where &ugr; is the rate of object movement, &tgr;—time constant of heated single sensing element.
Still further in accordance with a preferred embodiment of the present invention, the heat-loss sensor includes a two-dimensional ⊥-type matrix of heat-loss elements connected seq
Baydin Dmytro
Bazhenov Mykhaylo
Lukonin Oleksandr
Mishunin Bogdan
Cashcode Company Inc.
Pruchnic Jr. Stanley J.
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