Code Recognition Apparatus And Method

Abstract

Code-reading apparatus for identifying articles carried past a code reader by a conveyor, the apparatus using single and multiple digit codes.

Description

The automated handling of articles such as packages carried by a conveyor has become important in the operation of warehouses, post offices, etc. The articles are to be delivered by the conveyor selectively to various discharge points automatically, economically, and in a dependable manner. In automated conveyor systems, it has been common to apply to an article an encoding device which identifies the article in some respect. Commonly, the article is identified with the conveyor discharge point, or the article identification may signify the particular product, or the identification may signify both the discharge point and the product category. The encoding device need not be applied directly to the article but instead it may be applied to a part of the conveyor adjacent to the article.

An object of the present invention resides in providing article identification systems especially useful with conveyors. More specifically an object of the invention resides in providing a novel system including an encoding device and a code reader for interpreting identification codes and, more particularly, for recognizing a prescribed article identification code, the system being at once highly dependable in operation, and simple and easy to use by the conveyor attendants.

In the illustrative disclosure that follows, an article may be identified by a single number. The identification code consists of two tracks of code elements, one track having a series of pulse generation elements and another track that has a single control element. Both tracks are sensed concurrently, each by its own sensor. The sensed pulse generation elements provide pulses to a counter. The position of the control element in the second track corresponds to the number that it represents. The control element is located in its track at a position to be sensed by its sensor when the sensor of the pulse generation track has sensed a corresponding number of pulse generation elements. The number involved may be any value, from zero to nine or higher.

The described code reader also includes a present reference device that represents the article identification number against which the article code identification is to be checked. The comparison of the number in the counter and the present number in the reference device takes place under control of the sensor of the second code track. A signal is produced in the event of a match between the preset reference device and the count in the counter, and this evidence of match is stored.

As a further feature of the disclosed system, counting of the pulse generation elements is stopped under control of the second sensor, regardless of whether the value in the counter matches or does not match the preset value. In this way, the value registered by the counter represents the article-identifying code. This value can be used to activate a display device, and the value in the counter may also be supplied to accounting or data-accumulating systems.

As a further feature of the disclosed system, the article identification code can be enlarged to provide a multiple-digit article identifying number. A code that represents multiple numbers includes a track of pulse generation elements and plural control tracks each containing a control element in a position corresponding to one of the digits in the number represented by the code. A sensor is provided for sensing the pulse generation elements of the code and additional sensors are provided for sensing the control element tracks. The number of pulse generation elements can be counted up to the time that each control element is sensed. The count reached by the counting means up to the time that each control element is sensed is separately compared with a corresponding preset reference device. If each comparison provides an affirmative result, then a coincidence signal is produced showing identity of the multiple-digit article identification code and the multiple-digit number represented by the preset reference devices. If any one of the digits represented by any reference device differs from the count attained when its related control element is sensed, no article recognition or coincidence signal will be produced.

As a still further feature of the disclosed system as it relates to multiple-digit codes, multiple counters are used, each counter being arranged to count the pulse generation elements. Operation of the separate counters in counting pulse generation elements is stopped when the related control element in each of the several control element tracks is sensed. In this way, the values stored in the counters represents an interpretation of a multiple-digit code. The counters represent the code that is read, and the values in the counters can be used to provide a display of the article code or to transmit the article code to a central data collector, or for any other purposes.

The nature of the invention will be more fully appreciated from the following discussion of an illustrative embodiment of the invention which is shown in the accompanying drawings.

In the drawings:

FIG. 1 shows a novel article identification system, as an illustrative embodiment of the various features of the invention. FIG. 1 includes a block diagram of a code reader together with an article-identifying encoding device;

FIG. 2 is a simplified block diagram of a code reader utilizing some of the features of the embodiment in FIG. 1,

FIG. 3 is a diagrammatic perspective of a modification of a code scanner with an article-identifying code, useful in the system of FIG. 1.

Referring now to FIG. 1, a belt conveyor 10 is shown supporting an article 12 to which there is attached a code-bearing device 14. In the form illustrated, code-bearing device 14 has three tracks A, B and C generally represented by arrows. In the form illustrated, track A includes nine rectangular areas 16 on a background of contrasting color or reflectivity or both. Preferably sensed elements 16 are made up of glass beads on a bright reflecting coating so as to form a retroreflector. Other forms of retroreflectors are also useful such as an area covered by numerous three-sided right-angled reflecting corners. Other forms of photoelectrically sensed elements can be used, and indeed other forms of sensing devices and sensed elements may be utilized such as magnetic, pneumatic, etc., in installations where such alternatives are practical. In the preferred apparatus as shown, photodetector 18 is arranged to sense the separate elements 16 of track A, and a light source 20 directs a beam of light at the sensed reflecting surface of a half-silvered mirror 22 arranged to project the light beam to a small area of track A. A suitable complement of lenses (not shown) is ordinarily included with such photodetectors.

Tracks B and C contains respective control elements 24 and 26 that are formed of the same material as pulse generation elements 16. Control elements 24 and 26 are carried by respective plates 24a and 26a having formations at the back surface thereof complementary to support rails 28 and 30 of code-bearing device 14. These rails have detent formations 32 for engagement by the conforming parts of plates 24a and 26a. In this way control elements 24 and 26 can be located accurately in relation to any one of the pulse generation elements 16 in track A. Photodetectors 34 and 36 are directed for sensing those parts of tracks B and C which are in alignment with a pulse generation element of track A being sensed or which has just been sensed by photodetector 18. Lamps 38 are arranged to project beams against the reflecting surfaces of half-silvered mirrors 40 for illuminating the areas of tracks B and C being sensed by photodetectors 34 and 36 respectively.

It may be assumed that conveyor 10 carries article 12 from right to left and accordingly tracks A, B and C are sensed from left to right as the code-bearing device 14 moves leftward in relation to sensors 18, 34 and 36. In the course of this relative motion a series of pulses are produced by photodetector 18, and accordingly elements 16 are here called pulse generation elements. Elements 24 and 26 are sensed when none, one or more of pulse generation elements 16 have been sensed. Accordingly, depending on its position, each element 24, 26 produces a pulse output at its sensor 34 or 36 that represents a number of the generated pulses. Element 24 as shown is in the sixth position along track A and element 26 is at the third position in relation to track A, so that the code represented by encoding device 14 in this example is 25. If a control element 24 or 26 were located so as to be sensed before the first pulse generation element 16, then the number represented by that track would be zero.

Pulse-shaping circuit 42 transmits a train of pulses to gates 44 and 46 which normally transmit those pulses to counters 48 and 50. Gates 44 and 36 are bistable. Control pulses from photodetectors 34 and 36 are transmitted through pulse shapers 52 and 54 to a gate-closing connection of each of gates 44 and 46. When this occurs, gates 44 and 46 no longer transmit pulses to counters 48 and 50 even though the pulse shapers 42 may continue to emit pulses produced in response to pulse generation elements 16.

One adjustable preset device 56 is included for providing a representation of a number for comparison with the value represented by track B and another adjustable preset device 58 provides a numerical representation for comparison with the number represented by the control element 26 in track C. The value represented in the counter 48 when the related control element 24 is sensed is compared in comparer 60 with the numerical representation provided by preset 56, and likewise the value represented in counter 50 when the related control element 26 is sensed is compared in comparer 62 with the representation of preset 58. For example, counter 48 may be a series of binary stages and preset 56 may be combination-coded contact wheels having a pair of brush contacts for each of the binary stages in counter 48; and the comparer 60 may consist of a diode matrix in the nature of an "AND" gate suitably connected to the counter and the brushes of preset 56. Comparison networks are known in a variety of forms for detecting identity between the number represented by a preset and the number attained by a counter; and the preset and the counter can also assume a variety of different forms.

When gates 44 and 46 have both been closed by a signal from each of the sensors 34 and 36, each gate applies a control signal to AND-gate 64 whose output is connected to one input of AND-gate 66. Two other input signals to AND-gate 66 come from comparers 60 and 62. Thus, when the control elements 24 and 26 of both tracks B and C have been sensed, the value represented by the code-bearing device has been entered into the code reader. Gate 64 represents a device for providing an output signal showing that the reading of the number-representing control elements has been completed.

No transitory signal evidencing agreement between a preset and a value momentarily in counter 50 will have any lasting effect. A significant output is produced only in the event that the value in the counter is compared to the related preset when the corresponding control element 24 or 26 is sensed. For example, preset 56 might be set to a value "3" and if that were the case, there would be momentary agreement between preset 56 and counter 48 when the value in the counter reaches "3." However, this agreement would have no effect because gate 66 would be blocked at that time. The significant condition of a match between the preset and the counter occurs when the value in the counter at the time that a control element is sensed matches the related preset. Bistable gate 44, counter 48, preset 56 and comparer 60 all act together to produce and store an indication of a significant match condition having occurred. By virtue of storage gate 44, there is no possibility of a transitory match between the counter and the preset having any lasting effect. Moreover, by virtue of the bistable gate 44, the output in case of a match is held for use at a later time at the input connections of AND-gate 66. Likewise, gate 46, counter 50, preset 58 and comparer 62 act together to provide an indication of significant match between the preset and the value in the counter when the related control element is sensed, and to hold or store that indication at the related input to gate 66. Finally, when an indication is received that the code reading process has been completed (due here to an output signal from AND-gate 64) an article recognition signal will appear in the output of AND-gate 66 if the values represented by control elements 24 and 26 match the values represented by presets 56 and 58. That article recognition signal activates the utilization circuit at the output of AND-gate 66. In the illustrated diagram, the utilization circuit includes an amplifier 68 having a "hold" timer 70 arranged as a feedback loop to develop an extended output pulse for energizing a relay 72. Contacts 72a of this relay can be used to energize and conventional eject mechanism associated with the conveyor at or near the code-reading station or to activate a counter, or for both these purposes and others.

As indicated above, AND-gate 64 produces an output signal when the code reading process has been completed. That condition is evidenced by detection of a control element in every one of the control tracks B and C. When the code-reading process has been completed, the output signal from AND-gate 64 activates a delay timer 74. After a delay interval following an activating input signal, delay timer 74 produces a pulse for activating reset pulse generator 76 for resetting gates 44 and 46 for resetting counters 48 and 50. The delay timer is set to take effect after a delay interval long enough to allow time for utilization means 68, 72 to operated.

The code and code-reading system thus far described provides a means for recognizing whether or not the code of an article matches a present number. The particular form of the code reader provides a still further useful result. The actual value represented by code device 14 as read by the photoelectric sensors is entered into counters 48 and 50, as has already been noted, and the value is stored in the counters because gates 44 and 46 block subsequent input pulses. The counters are equipped with visual readout devices represented by rectangle 51 so that the sensed code of any given article is displayed by the counters in the code reader irrespective of whether or not the code of any particular article matches the value represented by a particular preset 57 and 59. By like token the value represented by code device 14 and stored in counters 48 and 50 when gates 44 and 46 become blocked is available for transmission via gates 80 to remote record-keeping equipment when AND-gate 64 produces an output signal showing that the operation of reading of the whole code is complete.

FIG. 2 illustrates a somewhat simplified system resembling that in FIG. 1. The code device 14 and the photosensitive scanning elements of FIG. 1 are not shown in FIG. 2. However, it is to be understood that a code device like that of FIG. 1 is to be used with the system of FIG. 2 having a track A of pulse-generating elements 16 and having one more track B in which there is a control element 24. The components of FIG. 2 that correspond to those in FIG. 1 bear corresponding primed reference numbers.

Pulse shaper 42' transmits a train of pulses in response to the successively sensed pulse generation elements in track A of the code device, and pulse shaper 52' provides a control pulse in response to sensing of a number-representing control element such as element 24 in track B of code device 14. The train of pulses is applied to gate 44' which normally transmits the pulses to counter 48'. When a control pulse from pulse shaper 52' blocks gate 44', pulse transmission stops. Preset 56' and counter 48' apply their number-representing signals to comparer 60'. When the control element of the code device has been sensed, then gate 44' is closed and gate 44' applies an enabling signal to AND-gate 66. This signifies the fact that the control element has been sensed.

In case a match should develop between counter 48' and preset 56' at some low value before a control element is sensed, there will be no output from gate 66'. This is because there is no enabling signal on the input of gate 66' from gate 44'. An output from gate 66' does occur if comparer 60' produces an agreement signal when the control element 24 is sensed. At that time and so long as gate 44' remains in its blocked state, the counter contains that value which the control element represents. After agreement has been determined in this way, the signal indication of a "match" is stored, in that gate 66' continues to provide an output signal. The output of gate 66' is transmitted to a suitable utilization circuit such as a relay for activating an article ejection device associated with the code-reading station or to a counter or to a central statistical machine.

The value in the counter 48' at the time that gate 44' is blocked is available for display and for transmission to central data-receiving equipment. This is so even in the event that the preset and the value in the counter representing a particular article should not match.

Output from gate 66' supplies a delay pulse source 74' to activate a reset pulse generator 76' for resetting counter 48' and for opening gate 44' in readiness to transmit pulses during sensing of the next article code device.

The article-identifying code device 14 and the code reader as described in connection with FIG. 1 is effective to provide an output in the event that the code represented by device 14 matches the values represented in presets 56 and 58. The values are ordinary digits from "0" to "9." However, and particularly in case only one control track is used, any practical number of pulse generation elements 16 can be used. Thus, there may be any number of pulse generation elements 16 such as 12 or more, and control element 24 can then be selectively positioned to represent any value from zero to 12 or more.

In ordinary practice article 12 is carried by a moving conveyor. Stationary sensors 18, 34 and 36 effect a scanning operation due to the motion of code device 14 past the sensors. However, it is not necessary to rely on the motion of the conveyor. The detectors can be mounted on a suitably driven scanning support such as is illustrated in FIG. 3. In that figure, the conveyor 10A carries an article that bears an encoding device 14A. The article may be stationary or slowly moving. Three photosensitive detectors 18A, 34A and 36A are driven to scan along the code-bearing tracks of device 14A. It will be understood that the sensors in FIG. 3 advantageously carry with them the light sources, the reflecting mirrors and the lenses that are customarily a part of the code-reading light-sensitive sensors.

Claims

I claim:

1. Apparatus for recognizing a code representing a multidigit number, comprising:

at least three readers, each reader including a light and a photoelectric sensor;

a code-bearing device having tracks disposed for sensing by said sensors, respectively, said tracks including a pulse generation track having a series of 10 retroreflective pulse generation elements and plural control tracks each having a retroreflective control element selectively movable to any one of 10 number-representing discrete positions to be sensed by its related sensor when a corresponding number of pulse generation elements have been sensed by the sensor of the pulse generation track, each discrete position located in alignment with one of the pulse generation elements;

plural means for counting output pulses produced by the pulse generation sensor, a different means for counting being associated with each of said control tracks;

gating means associated with each of said control tracks and a corresponding one of said means for counting and operative to halt each means for counting at a count corresponding to the position of its respective selectively movable element on said control track;

plural digit-reference-representing devices;

means for comparing the digits represented by each of said digit-reference-representing devices with the count reached by a respective counting means; and

means responsive to the comparing means for producing a multiple-digit number-recognition output signal but only in case of agreement of all counts reached by the counting means with its respective digit represented by each said digit-reference-representing device.

2. Apparatus in accordance with claim 1, wherein said means responsive to the comparing means includes an AND gate having plural inputs from said comparers respectively whereby lack of an agreement signal at any one of said inputs of the AND gate will prevent the AND gate from providing a recognition signal.

3. Apparatus in accordance with claim 1 including plural bistable devices controlled by said control track sensors respectively for preserving conditions separately attained by the comparing means when each control element is sensed and until all of the control elements have been sensed.