Abstract:
Commercial material processing machines such as garment laundering often entail conveyors and large containers (e.g., dryer drum, washer) that pose safety hazards to workers who work in proximity to the equipment, even safety procedures if followed would preclude the worker from inadvertently entering the machine. Having an interrogator antenna within the machine and a transmitter attached to the worker, such as a Radio Frequency Identification (RFID) tag provides a means for sensing when a worker is in a hazardous position. When sensed, safety circuitry shuts off actuators to prevent further conveying of material into the machine and movement of the large container (e.g., drum).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application hereby claims the benefit of the nonprovisional patent application Ser. No. 10/974,399, entitled “Garment Processing System and Method Thereof” to Jeffrey Aldridge, filed 27 Oct. 2004, and the two provisional patent application Ser. Nos. 60/866,942 and 60/894,706 filed respectively on filed 22 Nov. 2006 and 14 Mar. 2007, both to Jeffrey Aldridge and both entitled “Means For Limiting Access to Identifying Data”, the disclosures of which are hereby incorporated by reference in their entirety. 
         [0002]    The present application is related to two co-pending and commonly-owned nonprovisional patent applications filed on even date herewith entitled “RFID Private Protocol Apparatus” and “Garment Processing Personnel Safety Apparatus”, both to Jeffrey L. Aldridge, the disclosures of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0003]    The present invention relates, in general, to devices that enhance the productivity and safety associated with large volume garment processing (e.g., sorting, washing, drying, repair/replacement, storage and delivery), and more particularly to such improvements that prevent or mitigate injury to personnel who incorrectly operate such equipment having large openings and internal volume. 
       BACKGROUND OF THE INVENTION 
       [0004]    Commercial and industrial laundering facilities have become increasingly sophisticated in order to meet customer demand efficiently and economically. These facilities are generally large-scale operations and are capable of laundering and organizing thousands of garments per day. Although numerous equipment and procedural safeguards exist, it is desirable to add additional automated safety features. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0005]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention. 
           [0006]      FIG. 1  is a schematic representation of a generally-known example of a process for laundering, drying and sorting garments based upon a pre-sort buffer. 
           [0007]      FIG. 2  is a schematic representation of an example of a process for laundering, drying and sorting garments incorporating a multi-destination storage capability in lieu of a required pre-sort buffer. 
           [0008]      FIG. 3  is a schematic representation of an example of the process of  FIG. 2  further incorporating a garment tracking system. 
           [0009]      FIG. 4  is a rear view in elevation of a Radio Frequency Identification (RFID) Reader Station with a rear cover removed for the garment tracking system of  FIG. 3 . 
           [0010]      FIG. 5  is an isotropic view of the RFID Reader Station of  FIG. 5  with a magnetic flux diagram depicted for one ferrite horseshoe element. 
           [0011]      FIG. 6  is a front view of an illustrative pass-through garment dryer advantageously incorporating a drum RFID Reader Antenna for the processes for laundering, drying and sorting garments of  FIG. 1 ,  2  or  3 . 
           [0012]      FIG. 7  is a side view of the pass-through garment dryer of  FIG. 6  with an exemplary laundry conveyor system being misused. 
           [0013]      FIG. 8  is a diagram of an RFID tag and reader incorporating a two stage privacy algorithm. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    Referring now to the figures,  FIG. 1  shows a schematic of a generally-known process for laundering, drying, and sorting garments. Garments  12 , which are typically soiled, are delivered to the laundering facility by delivery vehicles  10 , typically delivery trucks. Each delivery of soiled garments  12  corresponds to a specific route. The soiled garments  12  are unloaded from the vehicle and may undergo a pre-wash sort  20  where the garments  12  may be separated by the type of garment  12  (e.g. garage wear, lab wear, etc.), by color (e.g. light, dark, etc.) and the like. Each garment  12  may include a permanent or temporary unique identifier  22 , such as an alphanumeric code, which may be unique to each garment or a class of garments. The identifier may be manually readable by workers or may be encoded in a machine readable format, such as a bar code, radio frequency (RF) chip, and the like. While the following embodiment is described in the context of machine readable identifiers, it is understood that it may be easily modified to accommodate manually readable identifiers. 
         [0015]    After the pre-wash sort  20 , the garments  12  are transferred to washing machines  30 , where they are washed. For the purposes of this description, “wash”, “washing” and “washed” may mean traditional laundering, dry cleaning, and the like and “washing machine” may refer to an apparatus for washing. After washing  30 , the garments  12  are transferred to dryers  40  where they are dried. Alternatively, the garments  12  may be dried as they pass through a steam tunnel  60 . Once dried, the garments  12  are transferred to an inspection station  50 . At the inspection station  50 , a worker may inspect the garments for damage such as rips, tears, missing buttons and such. After inspection, each garment  12  is configured for processing and placed on a conveyor  51 . Garments  12  may be configured for processing by being hung on hangers, folded or the like. The garments  12  may be delivered as configured for processing or may be subsequently configured for delivery by being hung on hangers, folded or the like. In one embodiment, a garment  12  is configured for processing by being hung from a clothes hanger  52  where the hanger  52  is attached to a carrier  54  that interfaces with the conveyor  51 . The carrier  54  may have an identifier (not shown) thereon. The identifier may be manually readable by workers or may be encoded in a machine readable format, such as a bar code, radio frequency (RF) chip, and the like. While the embodiment is described in the context of machine readable identifiers, it is understood that it may be easily modified to accommodate manually readable identifiers. A worker may then scan the garment&#39;s machine readable identifier. Once placed on the conveyor  51 , the garment&#39;s machine readable identifier  22  and carrier&#39;s machine readable identifier may be automatically associated in the sorter&#39;s computer (not shown). Once on the conveyor  51 , each garment  12  is conveyed to a repair station  70 , the steaming station  60 , or pressing station (not shown). Alternatively, the garments  12  may be steamed or pressed any time after washing, or not at all, and do not necessarily have to be steamed or pressed prior to sorting. While the garments  12  are being conveyed, the carrier  51  may be read at various points along the conveyor. Alternatively, it may be unnecessary to use carriers  54 . Instead, a machine readable identifier in the garment  12  may be read during conveying. 
         [0016]    The garments  12  not needing repair are steamed  60  to reduce wrinkles and conveyed to and collected in a pre-sort buffer  80 . For the purposes of this description, a “buffer” is a temporary accumulation of garments as part of serialized operations. For example, a buffer may hold garments  12  pending a predetermined subsequent operation. In such case, a buffer is coupled to a designated operation. Typically, a buffer would hold garments on the order of magnitude of hours. For instance, a buffer may hold garments  12  for less than eight working hours where “working hours” means the hours of operation of a laundering facility and does not include breaks such as overnight, when the facility is closed, or machine downtime for such things as repair, maintenance and the like. Furthermore, “pre-sort buffer” will refer to a type of buffer where garments are presorted based on route and temporarily accumulated as an immediate preceding step to a sorting operation. 
         [0017]    The pre-sort buffer  80  consists of several rails  82 , where each route is temporarily assigned to one or more rails. Based on reading the machine readable identifiers, each garment is conveyed to a pre-sort buffer rail  82  corresponding to its route. Once all, or a substantial majority, of the garments  12  for a route are collected on a rail  82 , the garments  12  may be directly conveyed to a sorter  90  where they are sorted by delivery sequence within the route. For instance, the sequence may be the order of deliveries to customers, by employees within a customer, by type of clothing, or any other order deemed desirable. Sorting may be performed manually by one or more workers or by sorting machines  90 . Once sorted, the garments  12  are automatically and immediately conveyed to storage  100  where they are stored until they are scheduled to be loaded for delivery  120 . For the purposes of this description, “storage” will refer to longer term holding, often, but not necessarily, encompassing a magnitude of days. Storage  100  is often where garments are kept prior to loading on a truck  10 , but may also include a temporary holding area for garments to be removed from the route prior to their delivery to a stockroom (not shown). Storage may also have no predetermined subsequent process step. For instance, one or more garments in storage could be routed to a variety of different locations or processes (e.g., repair, loading, removal, sorting, resorting, etc.). 
         [0018]    The garments  12  conveyed to the repair station  70  are repaired. Once a garment  12  is repaired, it may be placed onto the conveyor  51  and conveyed to the steaming station  60 , to the pre-sort buffer  80  and sorted  90  and stored  100  with other garments  12  of the route. However, if the route has already been sorted, the repaired garment  12  may be placed onto the conveyor  51 , conveyed to the steaming station  60 , to the pre-sort buffer  80 , sorted  90 , and a worker will then have to manually place the garment  12  in its proper place within storage  100  (e.g. with the garments  12  for the same customer, with the garments  12  for the same employee of the customer, etc.). 
         [0019]    Also, from time to time, it may be necessary to add new garments  12  to the route (e.g. for a new employee of a customer, etc.), add stragglers, or remove garments  12  from the route (e.g. for an employee who no longer works with a customer, etc.)  110 . For the purposes of this disclosure, “stragglers” will refer one or more garments  12  associated with a route that are separated from the remainder of the route. For example, a straggler may be a garment that is inadvertently left on or near the delivery vehicle  10 , dropped on its way to a washing machine  30  or a drying machine  40 , delayed in another process, separated from its hanger  52 , separated from the conveyor  51 , etc. For a new garment  12  or straggler, the garment  12  may be placed onto the conveyor  51  and conveyed to the steaming station  60 , to the pre-sort buffer  80  and sorted  90  and stored  100  with other garments  12  of the route. However, if the route has already been sorted, a worker will have to manually place the garment  12  in its proper place within the route within storage  100 . 
         [0020]    Referring now to  FIG. 2 , another embodiment of a process for laundering, drying and sorting garments is shown. Garments  12  are delivered to the laundering facility by delivery vehicles  200 , typically delivery trucks. Each delivery of soiled garments corresponds to a specific route. The soiled garments are unloaded from the vehicle and may undergo a pre-wash sort  210  where the garments may be separated by the type of garment  12  (e.g. garage wear, lab wear, etc.), by color (e.g. light, dark, etc.) and the like. Each garment  12  may include a permanent or temporary unique identifier  22 , such as an alphanumeric code, which may be unique to each garment or a class of garments. The identifier  22  may be manually readable by workers or may be encoded in a machine readable format, such as a bar code, radio frequency (RF) chip, and the like. While the following embodiment is described in the context of machine readable identifiers, it is understood that it may be easily modified to accommodate manually readable identifiers. 
         [0021]    After the pre-wash sort  210 , the garments  12  are transferred to washing machines  220 , where they are washed. After washing  220 , the garments are transferred to dryers  230  where they are dried. Alternatively, the garments may be dried as they pass through a steam tunnel  250 . Once dried, the garments are transferred to an inspection station  240 . At the inspection station  240 , a worker inspects the garments for damage such as rips, tears, missing buttons and such. After inspection, each garment  12  is configured for processing and placed on a conveyor. In one embodiment, a garment  12  is hung from a clothes hanger  52  where the hanger  52  is attached to a carrier  54  that interfaces with the conveyor. The carrier  54  may have an identifier thereon (not shown). The identifier may be manually readable by workers or may be encoded in a machine readable format, such as a bar code, radio frequency (RF) chip, and the like. While the embodiment is described in the context of machine readable identifiers, it is understood that it may be easily modified to accommodate manually readable identifiers. A worker will then scan the garment&#39;s machine readable identifier  22 . Once placed on the conveyor  51 , the garment&#39;s machine readable identifier and carrier&#39;s machine readable identifier may be automatically associated in the sorter&#39;s computer. While the garments  12  are being conveyed, the carrier  54  may be read at various points along the conveyor  51 . Alternatively, it may be unnecessary to use carriers  54 . Instead, a machine readable identifier  22  in the garment  12  may be read during conveying. 
         [0022]    Once on the conveyor  51 , each garment is conveyed to a repair station  260 , to a steaming station  250  (or pressing station (not shown)), or to storage  270 . The garments may be steamed  250  to reduce wrinkles prior to being conveyed to storage  270 , or the garments may be conveyed directly to storage  270  and steamed  250  at a later time. The garments  12  are grouped together in storage  270  based on route, but may be out of sequence. Based on reading the machine readable identifiers  22 , each garment  12  is conveyed to a storage rail corresponding to its route. The garments  12  may remain in storage  270  until it is determined that they may be sorted. This determination may be based on proximity to delivery date, the sorter being idle and the like. In one embodiment, the garments may be stored for at least 8 working hours prior to sorting. In another embodiment, the garments  12  may be sorted less than 36 clock hours from when they are scheduled to be loaded for delivery; where “clock hour” means one of the 24 equal parts of a day. From storage  270 , the garments  12  may be conveyed to a sorter  280  where they are sorted by delivery sequence within the route. For instance, the sequence may be the order of deliveries to customers, by employees within a customer, by type of clothing, or any other order deemed desirable. Sorting may be performed manually by one or more workers or by sorting machines. Once sorted, the garments  12  may be conveyed to a staging area (not shown) prior to loading for delivery  290 , may be loaded for delivery  290 , or may be conveyed back into storage  270  and loaded for delivery  290  at a later time. 
         [0023]    Also, garments  12  may be conveyed to the repair station  260  from the inspection station  240 , from storage  270  or from the steaming station  250 . The garments conveyed to the repair station  260  are repaired. Once a garment  12  is repaired, it may be placed onto the conveyor  51 , conveyed to the steaming station  250 , or conveyed to storage  270  and stored with other garments  12  from the same route. If the route has previously been sorted, the garment  12  may be conveyed to the end of the rail for the route and the route may be re-sorted by the sorter  280  to include the repaired garment  12  in its proper position within the route. Once re-sorted, the garments  12  may be conveyed to a staging area (not shown) prior to loading for delivery  290 , loaded for delivery  290 , or conveyed back into storage  270  and loaded for delivery  290  at a later time. Also, from time to time, it may be necessary to add new garments  12  to the route (e.g. for a new employee of a customer, etc.), add stragglers, or remove garments from the route (e.g. for an employee who no longer works with a customer, etc.). For a new garment  12  or straggler, the garment  12  may be placed onto the conveyor  51 , conveyed to the steaming station  250 , conveyed to storage  270  and stored with other garments  12  from the same route. If the route has previously been sorted  280 , the garment  12  may be conveyed to the end of the rail for the route and the route may be re-sorted by the sorter  280  to include the new garment, or straggler, in its proper position within the route. Once re-sorted, the garments may be loaded for delivery  290 , or may be conveyed back into storage  270  and loaded for delivery at a later time. For garments that are to be removed from the route, they may be conveyed from storage  270  to the stockroom (not shown). 
         [0024]    RFID AUTOMATED GARMENT PROCESSING. In  FIG. 3 , a process for laundering, drying and sorting garments is depicted that is similar if not identical to the process depicted and described above for  FIG. 2 , but with illustrative placement of sensing passive RFID tags  22 . As mentioned above, placing RFID tags  22  on garments  12  enhances identifying and tracking garments  12  as processed through a garment processing plant. Although one or more stationary RFID reader antennas (interrogator)  310  are depicted at various locations, it should be appreciated that handheld, steerable antennas with direction gain, or additional stationary antennas may be incorporated as desired or warranted. Typically, the stations  310  are configured such that an RFID tag  22  passes through or travels past the reception area for the station  310 . For example, a first station  310  is placed alongside an overhead rail  312  conveying a plurality of sling bags  314 , each containing in turn a plurality of garments  12 . Thus, the RFID tags  22  may be oriented in various directions (for instance, attached to a clean garment hanging on a hanger which is being conveyed on a conveyor, or attached to a soiled garment in a sling bag being conveyed on an overhead rail system). Illustrating other locations for RFID detection, another station  310  is placed alongside a hanger conveyor  316  between the steam tunnel  250  and storage  270  and a third station  310  is placed between storage  270  and delivery  290 . 
         [0025]    The RFID tag  22  is coupled electrically to the reader via electromagnetic induction (like the output coil of a transformer is coupled inductively to the input coil), both for providing power to the garment tag (i.e., the garment tag is passive, meaning it uses the power it receives from the reader signal to operate), and for communicating data between the garment tag and the reader (and optionally also from the reader to the garment tag). 
         [0026]    To get sufficient inductive coupling between the reader antenna and the garment tag antenna for successful communication between the reader and the garment tag, a certain minimum amount of magnetic flux generated by the reader antenna has to pass through the antenna coil of the garment tag  12 . If the garment tag is parallel or nearly parallel to the lines of magnetic flux at the point in space where the garment tag is located, sufficient inductive coupling will not be achieved. 
         [0027]    One typical approach to incorporating an RFID antenna into a garment  12  is to embed a tag antenna (not shown) within a protective coating or within a fluid impermeable pouch (not shown). This prevents contamination or physical damage to the very fine copper wire or lithographically applied conductive traces on printed circuit board of the garment tag coil. To get sufficient coupling, the plane of the garment tag coil (although the garment tag coil wouldn&#39;t necessarily have to be planar) has to be penetrated by a certain concentration of magnetic flux lines at an angle sufficiently perpendicular to the plane of the garment tag coil. 
         [0028]    In some applications, it is advantageous to use materials of high magnetic permeability (for example, magnetically-soft ferrites) to direct, steer, or shape the magnetic flux generated by the reader antenna  310  in such a way that as the garment tag  22  passes through the field of the reader antenna, it will, at some point along its path through space, encounter at least one place where the local intensity and direction of the lines of magnetic flux generated by the reader will be sufficient to allow successful communication with the reader. Previous attempts to create this condition necessary for successful communication have relied on one or more of the following: (a) physically varying the orientation of the garment tag antenna relative to the reader antenna  310  (by moving either the garment tag or the reader, or both) as it passes through the reader field; (b) using various shapes, configurations, and combinations of active and passive reader coils and other antenna elements (e.g., closed- or open-loop reflectors) that are electrically conductive; (c) electrically or electronically switching the reader signal between various antenna configurations or orientations; (d) passing the garment tag through or beside multiple readers with different antenna configurations or orientations. 
         [0029]    However, generally-known approaches fail to address shaping the detection magnetic field by use of materials of high magnetic permeability specifically for the purpose of directing or shaping the magnetic field generated by the reader antenna coil or coils to overcome tag orientation problems, although similar magnetic materials have been used for the purpose of shielding RFID reader fields from adjacent regions of space or from electrically conductive structures or devices. 
         [0030]    In  FIGS. 4-5 , an illustrative reader antenna  310  includes a generally vertically aligned serpentine conductor (e.g., copper pipe)  400  formed of alternating left and right rounded right angle bends  412 . For each bend  412 , a respective shallow ferrite horseshoe  414  is placed with its opening  416  toward a front surface  418  of a rectangular cabinet  420  that transversely faces the path of the sling bags  314 . An inner arm  422  or each horseshoe  414  is vertically aligned with the other inner arms  422 , residing inside of the laterally pointing apex formed by each bend  412 . The outer arm  424  of each horseshoe  414  is positioned vertically lower than the inner arm  422  of the same horseshoe  414  and on the other side of the bend  412 . Each horseshoe  414  alternates, approximately perpendicularly aligned with vertically adjacent horse shoes  414  and parallel to each horseshoe  414  above and below respectively the two that are adjacent. With particular reference to  FIG. 5 , each horseshoe  414  forms a canted magnetic flux field  428  such that any RFID tag  22  passing by the front  418  of the reader antenna  310  passes through flux fields  428  of multiple orientations ensuring a successful read. 
         [0031]    The use of these magnetic materials for the purpose of overcoming tag orientation problems also provides the additional benefits of: (a) making the reader antenna  310  more efficient by concentrating more of the energy of the generated magnetic field in the desired “read zone” of the reader antenna, and also by providing a lower reluctance path for the magnetic flux to travel through the non-read-zone regions of space; (b) reducing stray magnetic fields outside the read zone of the antenna which could cause undesired effects such as electromagnetic interference or health concerns; (c) creating a more compact read zone with well defined boundaries (important in some applications, for instance where one desires to know from the garment tag reads the order or spacing of tags that are conveyed sequentially into the read zone, or where one wishes to write information specifically to tags in the read zone without also writing it to nearby tags just outside the read zone). 
         [0032]    GARMENT ZIPPER SORT. With enhanced automated tracking of individual garments  12 , further enhancements are enabled with this ability to individually identify garments. The invention generally relates to garment processing in automated garment processing facilities. After garments are laundered, they are hung on hangers, each garment is given a unique serial number, and the garments are transported about the facility along conveyor rails. As garments are processed in an automated facility, they generally end up being out of order. The conveyor rails can branch, garments can be selectively routed along the various branches, and garments can be accumulated along rails. 
         [0033]    A random sequence of garments are accumulated in the initial buffer, which could entail a pre-sort buffer, a hanger conveyor, or a storage unit. As the garments  12  enter the initial buffer, they are scanned to determine their serial numbers. Once the conveyor buffer is completely populated (which could include 1000 or more garments), a computer system determines the correct sequence for the garments. Using a sorting algorithm (discussed in more detail below), the computer then calculates which garments  12  should be placed in which sorting buffers. The initial buffer is released and each garment  12  is conveyed to its respective sorting buffer. Once the sorting buffers are populated, one at a time a garment is released, in sequential order, from its sorting buffer until all the garments have been sequenced. 
         [0034]    An example of the sorting algorithm is illustrated in Tables. As shown in Table I, a random sequence of ten garments are populated in an initial buffer. As shown in Table II, the first garment (#3) is conveyed to the first sorting buffer. As shown in Table III, the second garment (#7) is conveyed to the second sorting buffer. As shown in Table IV, the third garment (#4) is conveyed to the first sorting buffer. The process continues until the initial buffer is emptied. Table V shows the garments placed in the sorting buffers. Once the sorting buffers are populated, one at a time a garment is released in sequential order. As shown in Table VI, garments 0-3 have been sequenced. Table VII shows the sequencing process completed. 
         [0035]    As described above, the sorting and sequencing is accomplished in a single batch run, but it is also contemplated that the sorting procedure could be accomplished in two or more iterations. With an iterative process, the garments leaving the sorting buffers would only be partially sequenced and would be conveyed back to the pre-sorting buffer to complete the sequencing. 
         [0036]    Optionally, the rail downstream from the presort buffer could branch to enable bi-directional population of the sorting buffers. In other words, rather than populating the sorting buffers only from the top, the buffers could also be populated from the bottom. Thus, the number of sorting buffers could be reduced. Table VII illustrates an example of how the sorting buffers could be populated. 
         [0000]    
       
         
               
             
           
               
                 TABLE I 
               
               
                   
               
             
             
               
                 accumulate garments in pre-sort buffer 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE II 
               
               
                   
               
             
             
               
                 begin sorting garments 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE III 
               
               
                   
               
             
             
               
                 continue sorting 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE IV 
               
               
                   
               
             
             
               
                 continue sorting 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE V 
               
               
                   
               
             
             
               
                 sorting completed 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE VI 
               
               
                   
               
             
             
               
                 sequencing garments 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE VII 
               
               
                   
               
             
             
               
                 garments sequenced from 0–9 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
           
               
                 TABLE VII 
               
               
                   
               
             
             
               
                 optional bi-directional population of sorting buffers 
               
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
               
                   
               
             
          
         
       
     
         [0037]    RFID-BASED PERSONNEL SAFETY SYSTEM. In  FIGS. 6-7 , a person  500  entering, falling into, or being pulled into an industrial washer or dryer  502  can be seriously injured or killed. Because of how quickly the person  500  may fall or be pulled in, or just due to physical distances, the person  500  may not be able to actuate an emergency stop switch to deactivate the equipment. Generally known approaches have limitations, such as a fixed-location emergency stop switch. A person  500  may not have time or be able to physically reach an emergency stop button, cord, or crash-bar mounted on the equipment. Another example is a mobile emergency stop switch. An emergency stop switch may be worn by the person that communicates to the equipment via radio frequency signals. However, even though it is physically located on the person, the person  500  may still be unable to actuate it for any of several reasons, including the speed of events, or the person being subjected to violent motion, or being injured or incapacitated. Also, depending on where the receiving antenna is located, the radio frequency signals may be blocked by the metal enclosure of the equipment. 
         [0038]    Advantageously, a badge or device  504  that may be worn or carried on the person  500  of someone working around dangerous equipment (e.g., industrial washers or dryers, document shredding machines)  502  that, when detected by the equipment  502  as being in a danger zone, would inhibit operation of the equipment  502  or would otherwise render it safe (e.g., stop motion and heat on a dryer), and optionally also set off an alarm  506 . This device  504  may use radio frequency signals, either actively emitting them or using them passively (e.g., like an Electronic Article Surveillance, Surface Acoustic Wave, or Radio Frequency Identification tag) to make its presence known to the equipment. 
         [0039]    In one possible implementation, an RFID (Radio Frequency IDentification) reader antenna  508  would be mounted on a non-rotating surface (for instance, on the inside of a dryer door)  510  such that the reader can detect RFID tags located anywhere within the interior of the dryer drum  512  and/or in close proximity to an opening  514  of the drum. On detecting the presence of an RFID tag which is normally worn by or carried on a person, the RFID reader antenna  508  would send a signal to the dryer  502  to cease all operations that may be hazardous to a person (i.e., in the case of a dryer  502 , to stop the drum rotation and turn off the heat). The signal may also cause other adjacent equipment (e.g., a loading or unloading device  516 ) to be stopped or otherwise put into a safe state. The alarm  506  may also be activated to alert others to the person&#39;s possible need for assistance. 
         [0040]    RFID PRIVATE PROTOCOL. With RFID, barcodes, or any other means intended to identify objects, animals, people, etc., there exist many problems with the potential for use of the identifying data by unauthorized entities (people, corporations, governments agencies, etc.), or for unauthorized purposes. For instance, these problems include compromising of the privacy of persons who can be associated with the identifying data, compromising of the security of data (such as social security or credit card numbers) that could be used to access financial or other confidential information, and compromising of data that could be used to track various activities of a person, corporation, or other entity. 
         [0041]    A means is needed for the representation of the identifying data (code) to be changed, either each time it is read or based on time or other events, such that only those (authorized) readers with the proper non-public knowledge will be able to decipher from the changing representation a persistent, unchanging code that can be used to identify the object, animal, person, etc. The advantages of being able to uniquely identify garments  12  during laundering, sorting and delivering are thus retained while preserving the anonymity of wearers of a particular garment  12 . 
         [0042]    A two-step transformation on the persistent identifying code creates a changing representation that can be displayed, transmitted, or otherwise made available to a reader. First, a triggering event (time, a counter, an external signal, etc.) causes a random or pseudo-random or otherwise changing code to be generated or otherwise obtained. This code is then applied to the persistent identifying code in a way such that authorized readers will be able to extract or deduce from the resulting intermediate code, the original persistent identifying code. For instance, the random or pseudo-random or otherwise changing code could be simply appended or pre-pended to the persistent code, or interspersed (as individual digits in binary or any other specific base or combination of bases) among the persistent code at known locations, or multiplied by a constant code that is numerically larger than the persistent code and arithmetically added to the persistent code. Other means of application are also possible. 
         [0043]    The second step of the transformation is to encrypt the intermediate code using any encryption means that will make it difficult or impossible for any reader or observer of the resulting representation to extract or deduce the original persistent identifying code without first decrypting the representation to recover the intermediate code in its unencrypted form. Only authorized readers will have access to the non-public key or keys required to perform this decryption, thus protecting the persistent identifying code from disclosure with strength at least equal to that of the encryption means used. Further protection may be afforded by the fact that certain additional information about how the random or pseudo-random or otherwise changing code was applied to the original persistent identifying code to create the intermediate code may be necessary in order to extract or deduce the original persistent identifying code from the intermediate code. 
         [0044]    Security can be enhanced by recursively performing both the first and second steps of the transformation (in alternating fashion) multiple times, using different random or pseudo-random or otherwise changing codes and/or different means of applying said codes, and different encryption keys and/or different encryption algorithms. Alternately, the first step could be performed once and then selectively omitted between various multiple applications of the second step, using different random or pseudo-random or otherwise changing codes and/or different means of applying said codes, and different encryption keys and/or different encryption algorithms. Using asymmetric encryption algorithms (which use separate keys for encryption and decryption) provides the added security benefit that the non-public key or keys required to perform the decryption do not need to be known to or stored by the encrypting device or entity. Version identifiers can be appended to the representation to indicate to the reader which of multiple means of applying the random or pseudo-random or otherwise changing codes, encryption keys, encryption algorithms, and sequences of steps were used to produce the representation. These version identifiers can either be appended to the representation prior to the application of any subsequent transformation steps, or later in the transformation process, including after the final transformation step. The particular set of means of applying the random or pseudo-random or otherwise changing codes, encryption keys, and encryption algorithms used and the particular sequence in which they are applied could vary between different encrypting devices or entities, and/or could be different at different times on any given encrypting device or entity. 
         [0045]    The diagram of  FIG. 8  shows an example of one possible implementation of this invention as it could be applied to the design of an RFID tag and reader. The values and lengths of all codes, keys, ID&#39;s, version numbers, and ID representations were arbitrarily chosen for illustrative purposes only. 
         [0046]    It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. 
         [0047]    While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications may readily appear to those skilled in the art.