Patent Document (Category 7):

turning now to the drawings , fig1 and 2 as described above illustrate a storage container system in which a plurality of essentially identical storage containers 10 - i for file folders capable of being electronically addressed by an associated local controller are arranged in a stacked configuration and electrically interconnected by means of data and power cables . each storage container 10 - i is provided with a storage container indicator 25 - i , which in the preferred embodiment is an led with a current draw when activated of about 15 . 0 ma . located within each storage container 10 - i is a storage container indicator activation circuit illustrated in fig3 . as seen in this fig ., a circuit board 50 has mounted thereon a resistor 51 , an amplifier 52 , a microcontroller unit ( mcu ) 53 , and an isolator circuit 58 . in the preferred embodiment , resistor 51 is a 0 . 5 ohm one watt resistor ; amplifier 52 is a type mcp6002 operational amplifier ; and mcu 53 is a type pic 16f1823 microcontroller unit available from microchip technology , inc . of chandler , ariz . isolator circuit 58 is used to isolate incoming signals on positive data conductor 55 from outgoing response signals generated by mcu 53 , such as the identification of the storage container in which mcu 53 is located ( the id send signal ). one terminal of resistor 51 is connected to the positive data conductor 55 of a usb bus . the other terminal of resistor 51 is coupled to the active signal input of amplifier 52 and to electrically conductive rail 17 . the output of amplifier 52 is coupled to a data input of mcu 53 . a control output of mcu 53 is coupled to the anode of indicator 25 of the associated storage container . the cathode terminal of indicator 25 is connected to the negative data conductor 56 of the usb bus . in operation , an incoming address on positive data conductor 55 is coupled via resistor 51 and rail 17 to the electronic circuitry in brace 21 of all folders operationally installed in all storage containers interconnected in the manner described above with reference to fig2 . when the incoming address matches the address stored in the electronic circuitry in one of the braces 21 , such as the brace 21 illustrated in fig3 , the visible address match indicator 24 on that brace 21 is activated . activation of the visible address match indicator 24 causes substantial current to flow through resistor 51 of the storage container containing the addressed brace 21 . this causes the output of amplifier 52 to change state , which signals mcu 53 to generate a signal to activate the storage container visible indicator 25 . since the incoming address is unique , no other folder brace visible indicator 24 will be activated . consequently , only the storage container visible indicator 25 in the storage container in which the addressed folder is located will be activated . as a result , a human operator can merely look for the storage container having the activated visible indicator 25 and proceed to that storage container to retrieve the sought file folder 20 . as noted above , each file folder 20 is provided with a visible power on indicator 23 which is activated whenever the associated file folder 20 is operationally installed in the storage container . in establishing the initial parameters for the storage container indicator activation circuit , the total current draw of the visible power on indicators 23 for the maximum number of file folders 20 which can be accommodated by a given storage container is calculated and the resultant value is used to set the operating threshold of amplifier 52 . this ensures that amplifier 52 will only signal mcu 53 to generate the activation signal for visible indicator 25 when an address match has occurred within a file folder 20 in that storage container . as will now be apparent , storage containers incorporating the invention afford the advantage of providing a unique observable response to the presentation of a file folder address to a file folder having electronic circuitry containing that file folder address . in particular , one and only one of the storage container visible indicators 25 will be activated in response to an address match between an address presented on the data conductor 55 of the data bus and a folder address stored in the folder brace circuitry . since only one storage container visible indicator 25 will be activated , locating the storage container housing the sought folder identified by the presented address on the bus is reduced to a simple matter of looking for the storage container with the activated visible indicator 25 . although the above provides a full and complete disclosure of the preferred embodiments of the invention , various modifications , alternate constructions and equivalents will occur to those skilled in the art . for example , while the invention has been described and illustrated with reference to a visible indicator 25 , it is equally applicable to storage container arrays having audible indicators , or a combination of both visible and audible indicators . in addition , while the invention has been described and illustrated in the context of an array of vertically stacked storage containers , it is equally applicable to an array of storage containers which are arranged horizontally or both horizontally and vertically . moreover , the invention is also conformable to other types of storage container bus interconnection arrangements than the cable arrangement shown and described . one such alternate interconnection arrangement is shown and described in commonly - assigned , co - pending u . s . patent application ser . no . 13 / 987 , 352 filed jul . 16 , 2013 for “ two stage draw latch for stackable storage box with removable cover ”, the disclosure of which is hereby incorporated by reference . therefore , the above should not be construed as limiting the invention , which is defined by the appended claims 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