Abstract:
The present invention relates to a method and apparatus for dimensionally sorting a group of received articles, like fruits and vegetables, and using the determined different sizes for differentiation during the subsequent processing and handling of the articles. Generally, the size and shape of each article is determined by the degree of deflection of one or more sensor heads located along a path the article is traversing. The determined size and shape is then used to direct the article during the subsequent processing and/or handling of the article.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method and apparatus for dimensionally sorting a group of received articles, and using the determined different sizes for differentiation during the subsequent processing and handling of the articles. More particularly, the present invention relates to a method and system of sorting articles, where the nature of the articles is such that the articles, by their nature, have inherent size and shape differences, like fruits and vegetables. 
     BACKGROUND OF THE INVENTION 
     There are several types of items/articles, which traditionally come in varying non-standard shapes and sizes. Included among these types of articles are most types of fruits and vegetables, as well as other types of articles which are generally grown and/or are produced by nature. However articles which come in varying non-standard shapes and sizes are not limited to only those items which are produced by nature, but also can occur in items which are largely man-made. For example hand-made articles, especially articles made using less sophisticated manufacturing techniques, can also exhibit the same differences or non-uniformities in both shape and size. 
     Individual items within groups of articles, which have varying shapes and sizes, can sometimes require special packaging and/or handling as a result of their specific size and shape. For example, specific machine tooling or processing technique may be limited to or better suited for use with items having a size or shape, which falls into a particular range. 
     While in some instances the reasons for sorting the articles may be for purposes of managing the physical demands associated with the subsequent handling of the article, in other instances the reasons for sorting the articles may be strictly for purposes of satisfying customer preferences. For example, in some instances, it may be desirable to group items having like size and shape together, so as to provide the customer with multiple items which are more uniform in nature, especially where product uniformity is either desirable or important. In a somewhat related instance a customer may be willing to pay a premium for articles which exceed or fall within a particular size and shape criteria, thereby creating an economic advantage for segregating and/or sorting the articles within a group. 
     Apples are a good example of one type of article, which by its nature inherently has varying shapes and sizes, for which it may be beneficial to sort based upon their size and shape. Where an apple is being sold for direct consumption by the consumer, the consumers preference may be for apples which are larger in size. When the same type of apple is sold for use by a food processing company the size and shape of the article may be relatively less important. This may especially be the case for a food processing company, where the subsequent processed form is generally independent of the articles&#39; original size and shape. One such example may be a food processing company which produces apple sauce. 
     However bigger may not always be better. For example, there may be a market for smaller bite size tomatoes for use in salads, which could similarly be sorted to insure size conformance that is consistent with consumer demand. 
     Several prior systems have been used to dimensionally sort articles into groups, which vary as to size and shape. One such example includes systems which use holes in screened beds, which allow certain smaller sized articles to pass through, while blocking certain larger sized articles. However the holes in the screened beds are limited in accuracy and are not easily adjustable, when size requirements change. These systems further experience limitations in the amount of product which may be processed in a given square area, and in a given amount of time. 
     Further prior systems have used sensors, which determine the product density and water content as the product passes underneath the sensors. However these systems generally do not determine the size or shape of the product. 
     Still further, machine vision systems for determining relative dimensioning have been previously used. But the computational processing and analysis time required by the machine vision systems have generally placed significant limitations on the production volumes which are achievable for these types of systems. This is especially true when systems make use of machine vision data which distinguish between several different grey-scale levels. 
     Consequently, it would be desirable to provide a method and a system for dimensionally differentiating between a plurality of articles of varying sizes and shapes, which can be performed with enhanced accuracy and in a relatively small amount of time. It would be further beneficial to provide a method and system, where the same system can be readily adjusted so as to detect between different varying sizes and shapes, and/or adjusted to accommodate different types of articles. 
     These and other objects, features, and advantages of this invention are evident from the following description of a preferred embodiment of this invention, with reference to the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for dimensionally sorting a plurality of articles received as a group, each article having varying size and shape. The method comprises the articles being conveyed along a path. The articles are then singulated into one or more single file rows, as the articles traverse the path. The dimensional characteristics of the articles are then detected by detecting the deflection of one or more sensor heads which passively interfere with the progress of each of the articles, as the articles are conveyed. The articles are then differentiated between a plurality of respective size/shape groupings, based upon the detected dimensional characteristics. 
     In at least one further embodiment, differentiation of the articles between a plurality of respective size/shape groupings includes storing data associated with the detected dimensional characteristics for each of the articles. In some instances the data stored represents decision data for use in the subsequent processing of the article. In other instances the data stored represents data descriptive of the determined physical dimensional characteristics. 
     The present invention further provides a system for dimensionally sorting a plurality of received articles, each article having a varying size and shape. The system includes a conveyor having one or more paths along which the articles are formed and transported in single file rows. One or more sensor heads are positioned at one or more points along the one or more paths of the conveyor. Each sensor head includes a contact shaft which passively engages the articles and deflects an amount corresponding to the size/shape of the article passing in proximity thereto. A processing unit receives the sensor head readings and makes a determination of the size/shape of the articles and produces output data for later differentiation of the articles. 
     In at least one embodiment, the system further includes a memory for storing data corresponding to the determined size/shape characteristics of each of the articles. In some instances the data is representative of the physical characteristics. In other instances the data is representative of decision data to be used to determine or control the subsequent processing of the article. 
     In a further embodiment, the system includes a sorter for diverting the articles into one of a plurality of size/shape groupings based upon the determined size/shape characteristics of the article. 
     Other features and advantages of the present invention will be apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a dimensional sorter system, in accordance with the present invention, partially cut-away to better illustrate the sensor heads; 
     FIGS. 2A and 2B are both a side plan view and a top plan view of one embodiment of the dimensional sorter, shown in FIG. 1, as an add-on to an existing conveyor; 
     FIGS. 3A and 3B are both a side plan view and a top plan view of one embodiment of the dimensional sorter, shown in FIG. 1, as a stand-alone unit; 
     FIG. 4 is a top plan view of a dimension sorter for diverting the articles into one of a plurality of size/shape groupings based upon the determination of the size/shape characteristics of the article; 
     FIG. 5A is a front plan view of a sensor head arrangement using a photo-electric detection arrangement; 
     FIG. 5B is a partial schematic arrangement and cross sectional side plan view of the sensor head, shown in FIG. 5A; 
     FIG. 6A is a front plan view of a sensor head arrangement using a machine vision detection arrangement; 
     FIG. 6B is a partial cross sectional side plan view of the sensor head, shown in FIG. 6A; 
     FIG. 7A is a front cross sectional plan view of a sensor head arrangement using an absolute position encoder arrangement; 
     FIG. 7B is a partial side plan view of the sensor head, shown in FIG. 7A; 
     FIG. 8A is a front cross sectional plan view of a sensor head arrangement using a pulse encoder arrangement; 
     FIG. 8B is a partial side plan view of the sensor head, shown in FIG. 8A; 
     FIG. 9 is a schematic diagram and front plan view of a sensor head arrangement using a potentiometer; 
     FIG. 10 is a schematic diagram and front plan view of a dual sensor head arrangement using a pair of potentiometers; 
     FIG. 11 is a block diagram of a processing unit for use in the dimensional sorter system, illustrated in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described presently preferred embodiments with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     FIG. 1 illustrates an isometric view of a dimensional sorter system  10 , in accordance with the present invention. The dimensional sorter system either includes or rests upon a conveyor  12  which transports articles to be sorted through the dimensional sorter system. Generally, the dimensional sorter system  10  includes a plurality of path dividers or lane divider sidewalls  14  oriented substantially parallel to one another, thereby forming one or more singulating lanes or paths  16  therebetween, through which articles to be sorted can travel. 
     In FIG. 1, one of the lane divider sidewalls  14  has been partially cut away to more clearly illustrate several sensor heads, which are positioned at multiple points along each of the paths  16 . In the illustrated embodiment, one sensor head  18  or vertical axis sensor is supported by a cross mount  20  near the top and between two of the sidewalls  14 . The sensor head  18  is arranged such that an associated probe arm or contact shaft  22  extends downward at a slight angle. 
     The contact shaft  22  extends into the path  16 , through which articles to be sorted will travel, and passively engages any articles that pass therethrough. As articles pass beneath the sensor head  18 , and come into contact with the contact shaft  22 , the contact shaft  22  will deflect an amount corresponding to the size and shape of the article passing proximate thereto. In the case of the sensor head  18 , the amount of deflection corresponds to the height of the article. Generally, each path  16  has a corresponding sensor head  18  supported by a cross mount  20 . 
     The illustrated embodiment further includes a pair of oppositely facing sensor heads  24  or horizontal axis sensors, which extend inward towards the corresponding path  16  from respective sidewalls  14 . Similar to the contact shaft  22  of the vertical axis sensor, the horizontal axis sensors  24  have contact shafts  26 , which extend into the path  16  for passively engaging any articles passing therethrough. However, instead of deflecting upward, the contact shafts  26  of the horizontal axis sensors  24  together deflect outward an amount corresponding to the width of the article passing therebetween. 
     FIGS. 2A and 2B illustrate both a side plan view (FIG. 2A) and a top plan view (FIG. 2B) of one embodiment of the dimensional sorter  30 , consistent with the dimensional sorter system  10 , shown in FIG.  1 . Specifically the dimensional sorter  30  illustrated in FIGS. 2A and 2B could be used as an add-on to an existing conveyor  32 . Similar to the dimensional sorter  10 , discussed in connection with FIG. 1, the dimensional sorter illustrated in FIGS. 2A and 2B also includes a plurality of lane divider sidewalls  14 , which define one or more article paths  16 , and a plurality of sensor heads  18  and  24  positioned at multiple points along the length of the article paths  16 . 
     Additionally shown in FIGS. 2A and 2B are examples of a plurality of articles  34  being conveyed along the conveyor  32  and through the one or more paths  16 . In the specific example illustrated in FIGS. 2A and 2B, the shapes of the articles  34  correspond to the shapes of potatoes, one such type of article which is well suited for use with the present invention. In FIG. 2A, one of the articles, article  36 , is shown engaged with one of the contact shafts  22  of sensor head  18 . In FIG. 2B, an article  38  is shown engaged with the contact shafts  26  of a pair of sensor heads  24 . Contact shafts  22  and  26  are shown in both a deflected position and an undeflected position. 
     By monitoring the degree of deflection of the contact shafts  22  and  26  of both sets of sensor heads  18  and  24 , the dimensional sorter can determine both the varying height and width of the articles  34  being sorted. Generally as the article  34  passes the sensor heads  18  and  24 , a corresponding surface outline can be determined or a maximum magnitude can be determined in that dimension. It is further possible to determine length if the speed at which the articles  34  pass between or beneath the sensor heads  18  and  24  is known. 
     FIGS. 3A and 3B illustrate both a side plan view (FIG. 3A) and a top plan view (FIG. 3B) of a further embodiment of the dimensional sorter  40 , consistent with the dimensional sorter system  10 , shown in FIG.  1 . The dimensional sorter  40 , shown in FIGS. 3A and 3B is a stand-alone unit which can be interspersed between other elements in the processing path of the articles. While the top plan view, shown in FIG. 3B, is generally similar to the top plan view, shown in FIG. 2B, differences can be seen between the two side plan views, FIGS. 2A and 3A. The stand-alone dimensional sorter  40  includes its own conveyor  42 , and likewise its own supports  44 . 
     The system illustrated in FIG. 3A shows at least one further difference. Specifically, articles are conveyed to the dimensional sorter  40  via a vibratory feeder  46 , as opposed to a conveyor  32 . However one skilled in the art will readily recognize that any suitable method of conveying articles  34  could be used, including the use of a conveyor. 
     Otherwise the dimensional sorter  40  operates similar to the dimensional sorter  30 , shown in FIGS. 2A and 2B, including the operation of the sensor heads  18  and  24  in determining the dimensional characteristics of the articles  34 , not shown. 
     After the dimensional characteristics of the articles  34  are determined, subsequent processing stations can serve to sort or segregate the articles  34 , based upon the determined characteristics and the desired sort criteria. One example of a suitable dimension sorter  50  is illustrated in FIG.  4 . Specifically, the dimension sorter diverts the articles  34  between one of a plurality of size/shape groupings, based upon the determination of the size/shape characteristics of the article  34 . 
     In the specific example, deflection gates  52  can be selectively positioned to either allow the article  34  to continue along the path unobstructed, or can be positioned to divert the article  34  to an alternative path. The alternative path can then direct the article  34  to an alternative destination, or could further divert the article  34  to a further alternative path. In the illustrated embodiment, one of the paths  54  is represented by a conveyor which extends all the way to a subsequent article mover  56 . The other path or alternative path  58  is represented by a conveyor which stops short of the article mover  56 , thereby causing the article  34  to miss the article mover  56  and fall into a collection bin  60 . 
     In the present example, the articles  34  collected in the bin  60  might be of a desired size to be sold as is, while the articles  34  which continue on via the article mover  56  might be routed for further processing, like cutting into french fries. 
     The specific sensor heads, which passively interfere with the articles and detect the varying degrees of deflection of the associated contact shaft can take many different forms. Several examples of suitable sensor heads are described in the present application, and include photo-electric type sensors, potentiometer type sensors, encoder type sensors, electric type sensors, and machine vision state type sensors. One skilled in the art may recognize that other types of sensors would similarly be suitable without departing from the teachings of the present invention. 
     Of the included examples, the first of these, a photoelectric type sensor  70 , is illustrated in FIGS. 5A and 5B. Generally the sensor  70  includes a contact shaft  72  and two plate-like elements  74  and  76  which rotate with respect to one another. A first plate  74  remains relatively stationary, and the second plate  76  is coupled to the contact shaft  72 , and rotates as the contact shaft  72  is deflected. 
     The first plate  74  includes a window like opening  78 , which in the illustrated embodiment is rectangular in shape. The second plate  76  similarly includes an opening  80 , but instead of being rectangularly shaped, the opening  80  tapers along its length, and extends for a significant length beyond the limits of the window like opening  78  of the first plate  74 . Dependent upon the relative rotational orientation of the two plates  74  and  76 , a different portion of the tapered opening  80  will coincide with the window opening  78 . Thereby altering the size of the openings  78  and  80  which coincide with one another and creates a common opening which extends through both plates  74  and  76 . The size of the openings  78  and  80  which coincide with one another similarly affects the amount of light which can traverse through both of the openings  78  and  80 . 
     A light source or light emitting diode  82  is located on one side of the pair of plates  74  and  76  at a position which coincides with the window-like opening  78  in the first plate  74 , and a photo-detector transistor  84  is located on the opposite side of the pair of plates  74  and  76  at a position which similarly coincides with the window-like opening  78  in the first plate. The amount of light from the light emitting diode  82 , which traverses both openings, is detected by the photo-detector transistor  84 , which produces a correspondingly variable level signal that can be monitored to indicate the degree of deflection. 
     FIGS. 6A and 6B illustrate a machine vision state type sensor  90 . The machine vision state type sensor  90  similar to the photo electric type sensor  70  includes a pair of plate-like elements  92  and  94 , which rotate with respect to one another. Plate-like element  92  is relatively rotationally stationary, and plate-like element  94  is relatively rotationally non-stationary. Coupled to the non-stationary one  94  of the two plate-like structures is a contact shaft  96 . Each of the plate-like elements  92  and  94  have a plurality of holes  98 , which selectively align with corresponding holes  98  in the other plate-like element, depending upon the rotational orientation of the two plate-like elements  92  and  94 . 
     Similar to the photo-electric type sensor, when corresponding holes  98  in each of the plate-like elements  92  and  94  are aligned, light from a light source  100  on one side of the pair of plate-like elements  92  and  94  can be detected by a light detector or sensor array  102  located on the opposite side of the pair of plate-like elements  92  and  94 . Examples of suitable sensor arrays include CCD&#39;s (charge coupled devices), CID&#39;s (charge injection devices), and photo diodes or photo diode arrays. 
     Using a machine vision state sensor  90  of the type described in connection with FIGS. 6A and 6B, the corresponding holes  98  in the plate-like elements  92  and  94 , may be configured to align when the plate-like elements  92  and  94  are at a specific rotational orientation with respect to one another. Alternatively specific ones of the corresponding holes  98  may be configured to alternatively align dependant upon the degree of rotation. In this instance the sensor array  102  would be configured to discern which of the holes  98  are aligned in order to determine the degree of rotation. 
     An example of a first encoder type sensor head  110  is illustrated in FIGS. 7A and 7B. Similar to the other previously described types of sensor heads, the encoder type sensor head  110  also includes two plate-like elements  112  and  114 , which rotate with respect to one another. The first one of the plate-like elements  112  is relatively stationary, and the second one of the plate-like elements  114  rotates relative to the first one of the plate-like elements  112 . A contact shaft  116  is coupled to plate-like element  114 . 
     In the illustrated example, the first plate-like element  112  includes four contacts  118 , which extend towards and are aligned with a series of corresponding discontinuous tracks  120  located on the second plate-like element  114 . The presence and absence of the particular track segments  120  adjacent to the respective contacts  118  at a particular rotational orientation, can be used to uniquely identify the relative rotational orientation of the two plate-like elements  112  and  114 , with respect to one another. 
     In order to facilitate detection of when a particular contact is adjacent a particular track segment  120 , the track segments  120  could be formed of a conductive material and coupled to an electrical potential corresponding to a particular logic level. The logic level or electrical potential of the contact  118 , which could be biased through a resistor to an alternative logic level, could then be used to determine whether the contact  118  is adjacent to an existing track segment  120 . 
     Any number of tracks  120  and corresponding contacts  118  could be used. By using four tracks and four contacts, up to sixteen different zones could be defined. The use of more tracks and contacts would enable the sensor head to distinguish between an even greater number of zones. Additionally, while the illustrated example shows different zones defined which extend rotationally a full 360 degrees, the different zones could be restricted to an area less than 360 degrees, thereby allowing distinction between a finer degree of rotation using a fewer number of conductive tracks  120  and corresponding contacts  118 . 
     An alternative second encoder type sensor head  130  is illustrated in FIGS. 8A and 8B. The alternative encoder type sensor head  130  similarly has two plate-like elements  132  and  134 , which rotationally move with respect to one another, a first plate like element  132 , which is relatively rotationally stationary, and a second plate-like element  134  having a contact shaft  136  coupled thereto, and which rotates with respect to the first plate-like element  132 . 
     Similar to the other encoder type sensor head  110 , illustrated in FIGS. 7A and 7B, the first plate-like element  132  has a contact  138 . The second plate-like element  134  has a corresponding single row of discontinuous track segments  140 , which extends in a circle around the rotational center  142  of the two plate-like elements  132  and  134 . As the contact  138  travels across each one of the discontinuous track segments  140 , a pulse output is generated. 
     However instead of statically determining the rotational orientation of the two plate-like elements by determining, which ones of the plurality of contacts  118  are presently adjacent corresponding track segments  120 , as in the encoder type sensor head  110 , illustrated in FIGS. 7A and 7B, the alternative encoder type sensor head  130 , illustrated in FIGS. 8A and 8B, tracks the present rotational orientation or degree of deflection by counting the number of pulses received. By monitoring the number of pulses and the relative direction of rotation, a present indication of the rotational orientation of the two plate-like elements can be maintained. 
     A further sensor type is illustrated in FIG. 9, and includes a potentiometer type sensor  150 . However instead of incorporating two plate like elements, the potentiometer type sensor  150  has a sensor body  152 , which includes a resistor  154  having a length which extends circumferentially within the sensor body, around at least a portion of the sensor body, and an armature  156  coupled to a contact shaft  158 , which as the contact shaft  158  is deflected causes the armature  156  to contact the resistor  154  at differing points along the resistor&#39;s length. 
     One end of the resistor  154  is coupled to a first terminal  160  maintained at a first source electrical potential. The other end of the resistor  154  is coupled to a second terminal  162  maintained at a second source electrical potential. A third terminal  164  coupled to the armature  156  has an electrical potential which is dependent upon the point along the length of the resistor  154 , at which the armature  156  is in contact with the resistor  154 . In many instances the electrical potential at the third terminal is linearly proportional to the relative distances between the point of contact of the armature  156  and the two ends of the resistor  154 . 
     FIG. 10 illustrates an alternative embodiment of a potentiometer type sensor  170 , which incorporates two contact shafts  172  and  174 , each of which is associated with a different armature  176  and  178 , and a corresponding resistor  180  and  182 . While the respective ends of resistors  180  and  182  can be commonly coupled to corresponding source electrical potentials  184  and  186 , each armature is coupled to its own output terminal  188  and  190  for providing an output potential depending upon the contact shafts&#39; relative degree of deflection. 
     The illustrated potentiometer type sensor  170  incorporating two separate sensor outputs and corresponding contact shafts  172  and  174 , is particularly useful for use in connection with sensor heads  24 , illustrated in FIGS. 1-3, where the sensor is located in a divider sidewall  14  separating two adjacent article paths  16 . 
     One skilled in the art will readily recognize that other types of sensors would similarly be suitable without departing from the teachings of the present invention including other sensors of similar types but varying construction, and other sensors of different types. 
     The dimensional sorter system  10 , illustrated in FIG. 1, in at least one embodiment, further includes a processing unit  200 , which receives the detected sensor values, makes the corresponding determinations as to the size and shape of the articles  34 , and produces output data for use in the later differentiation of the articles  34 . A partial schematic of an example of one such processing unit  200  is illustrated in FIG.  11 . 
     The processing unit  200  includes a micro-controller  202 , which has one or more sensor input ports  204  and one or more output control ports  206 . The sensor input ports  204  are coupled to the various vertical and horizontal sensor heads  18  and  24 , for receiving signals indicative of the degree of deflection as articles pass adjacent to the sensors  18  and  24 . 
     Where the sensor heads output an analog signal, analog-to-digital converters  208  can be coupled between the sensor heads  18  and  24  and the micro-controller  202 , and used to convert the analog output signal into a digital form. In some instances the analog-to-digital converters  208  can be integrated as part of the micro-controller  202 . 
     The micro-controller  202  can then process the signals received from the sensor heads  18  and  24  and make determinations as to the size and shape of the articles  34 . The results of the processing can then be stored in a memory  210 , and/or used to directly control the subsequent processing of the article  34 . Storing the results can sometimes be beneficial where there is a delay between when the determination is made and when control signals for the subsequent processing needs to be received. In most systems, there is an inherent amount of time or delay required for the article  34  to be conveyed between the sensor heads  18  and  24  of the dimensional sorter system  10  and the subsequent processing stations where product differentiation data is used. 
     In some systems the dimensional data is stored as data indicative of the physical characteristics of size and shape of the article. In other systems the dimensional data is stored as decision data indicative of how the subsequent processing stations should alternatively handle the article  34 , during subsequent processing. In either instance, at the appropriate time, the micro-controller produces an output signal, which is provided via the one or more output control ports  206  to the subsequent processing stations for properly differentiating between the handling of the articles  34 . 
     Similar to the analog-to-digital converters  208 , the memory  210  could be integrated as part of the micro-controller  202  or could be maintained separate therefrom. 
     The micro-controller  202  receives a number of sensor input control signals  204 , which generally corresponds to the number of article paths  16  and the number of sensor heads  18  and  24  per article path  16 . The micro-controller further produces a number of output control signals  206 , which is generally dependant upon the number of subsequent processing stations and the number of signals required for each of the processing stations. 
     From the foregoing, it will be observed that numerous modifications and variations can be effected without departing from the true spirit and scope of the novel concept of the present invention. It is to be understood that no limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.