Abstract:
Systems and methods for automatically reordering parts are disclosed. In one embodiment, a system includes a tray adapted to support parts, and a resilient member operatively engaged with the tray that flexes according to the weight of parts stored on the tray. A switch generates a signal when the amount of parts on the tray is less than a predefined amount. A central processing unit coupled to the switch receives the signal generated by the switch and automatically reorders parts based on the received signal from the switch.

Description:
FIELD OF THE INVENTION 
   This invention relates generally to inventory control and, more specifically, to automated inventory control. 
   BACKGROUND OF THE INVENTION 
   Most prior inventory accounting methods have shortcomings at the input end. Often, inventory is initially taken manually. From then on, constant inventory accounting is maintained by accurate accounting of all transactions into and out of stock. However, that type of inventory accounting is slow, expensive, and requires meticulous acquisition and handling of inventory data. Often the inventory derived by the constant accounting of transactions into and out of stock is inaccurate because of unaccounted for transactions, spoilage, breakage, pilferage, improper identification of number or type of goods in stock, or for other reasons. Accordingly, means have been devised for accurately determining how many items are present at selected storage sites. 
   U.S. Pat. No. 4,419,734 issued Dec. 6, 1983 to Wolfson et al. is an example of a shelf weight sensing apparatus that analyzes solenoid signals produced by a weight sensor. The weight sensor is attached to a shelf in order to determine the precise number of inventory items located on the specified shelf. This type of system is expensive because it requires extensive circuitry for analyzing the signals received from multiple weight sensors. In addition, this type of system is made for stationary shelving systems which is not conducive to other forms of inventory storage and control. 
   Therefore, there exists an unmet need to provide a low-cost weight sensing inventory control system for moveable shelves or drawers. 
   SUMMARY OF THE INVENTION 
   The present invention provides systems and methods for automatically reordering parts thereby providing inventory control. In one embodiment, a system includes a tray adapted to support a plurality of parts, and a resilient member operatively engaged with the tray and adapted to flex according to the weight of parts stored on the tray. A switch generates a signal when the amount of parts on the tray is less than a predefined amount. A central processing unit coupled to the switch receives the signal generated by the switch and automatically reorders parts based on the received signal from the switch. 
   In one aspect of the invention, the resilient member includes a leaf spring or a helical spring. In another aspect of the invention, the tray is a slidable drawer having a floor supported by the resilient member. The switch engages one of the floor or the resilient member under a first weight condition and disengages with one of the floor or resilient member under a second weight condition. The first weight condition is greater than the second weight condition. 
   In a further aspect of the invention, a slidable rail structure supports the drawer and the resilient member supports the rail structure. The switch engages one of the rail structure or resilient member under a first weight condition and disengages one of the rail structure or resilient member under a second weight condition. The first weight condition is greater than the second weight condition. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings. 
       FIG. 1  illustrates a block diagram of an example system formed in accordance, with an embodiment of the present invention; 
       FIG. 2  illustrates a flow diagram of an example process performed by the system shown in  FIG. 1  in accordance with an embodiment of the present invention; and 
       FIGS. 3 ,  4 ,  5 A-C,  6 , and  7  illustrate various embodiments of weight sensors incorporated into a storage unit. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is directed to systems and methods for providing automatic inventory tracking of materials stored in moveable shelves or drawers. Many specific details of certain embodiments of the invention are set forth in the following description and in  FIGS. 1-5  to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description. 
   In one embodiment, the present invention is an automated inventory control system that uses movable weight sensing shelves or drawers for providing inventory trigger signals based on a sensed weight of a shelf or a drawer that stores an inventory of parts.  FIG. 1  illustrates an exemplary computer-based system  20  that automatically performs inventory sensing and automatic reordering based on a sensed inventory. The system  20  includes a plurality of weight sensors  24  located in conjunction with slidable shelves or drawers that are operatively coupled to a central processing unit (CPU)  30 . The CPU  30  is connected to memory  34  and to a supply system  32  over a public or private data network  36 . It will be appreciated that the CPU  30  may communicate in various other ways, such as, without limitation, by facsimile or electronic mail, with the supply system  32 . 
     FIG. 2  illustrates an exemplary method  40  performed by the system  20  ( FIG. 1 ) in accordance with an embodiment of the invention. First, at block  42 , each weight sensor  24  may generate a signal when the sensed weight of parts, materials, goods, etc. in the respective shelf falls below a predefined threshold amount. Next, at block  44 , the generated signal is sent to the CPU  30 . At block  46 , the CPU  30  identifies the part or parts that are associated with the weight sensor  24  that generated and sent the signal. In one embodiment, the CPU  30  may use information stored within the memory  34  to identify the part stored on the shelf or drawer associated with the weight sensor  24 . For example, the CPU  30  determines the part that is associated with the weight sensor  24  by comparing the identifier to a list or table previously stored in the memory  34 . In another embodiment, an identifier may be included in the signal generated by the weight sensor  24 . Next, at block  48 , the CPU  30  may inform inventory control personnel that the part within the shelf or drawer that is associated with the weight sensor  24  that generated and sent the signal is low. The CPU  30  may automatically request a re-order for the part associated with the shelf or drawer at block  49  via the network  36 , email, fax, etc. It will be appreciated that the CPU  30  can perform ordering in a number of ways, including, for example, by sending a message directly to a re-supplier or the supply system  32  over the network  36 . 
   In an alternate embodiment, the weight sensor  24  activates a light or some other indicator (visual or audible) at the shelf or drawer or at a central location for providing a visual indication of the need for restocking/re-ordering to an employee. 
     FIG. 3  illustrates a cross-sectional view of an exemplary inventory storage shelf  50  in accordance with another embodiment of the present invention. The shelf  50  includes a storage area  52  that is formed by sidewalls  54  and a weight sensing floor  56 . The weight sensing floor  56  is supported by a leaf spring  60 . The leaf spring  60  allows the weight sensing floor  56  to move within the storage area  52  based on the amount of weight the weight sensing floor  56  supports. The weight sensing floor  56  is preferably not permanently attached to any of the sidewalls  54 . In this embodiment, a switch  62  is positioned underneath the weight sensing floor  56 . The switch  62  maintains contact with the leaf spring  60  or the weight sensing floor  56  as long as the weight of the parts supported by the weight sensing floor  56  is greater than a threshold amount. If the weight of the items on the weight sensing floor  56  falls below the threshold amount, in other words the number of parts within of the shelf  50  is below a threshold amount, the leaf spring  60  forces the weight sensing floor  56  away from the switch  62  thereby toggling or triggering the switch  62 . The toggled switch  62  sends a signal to the CPU  30 . For example, if the shelf  50  includes a number of two-ounce bolts and the user wants the shelf  50  to begin a re-supply activity when there are only eight bolts left within the shelf  50 , then the type of leaf spring  60  is selected so it forces the weight sensing floor  56  away from the switch  62  when only a pound of parts (16 oz.) remains. 
     FIG. 4  illustrates a cross-sectional view of an exemplary inventory storage shelf  80  that includes a helical spring  84  and a switch  82  in accordance with yet another embodiment of the present invention. The helical spring  84  supports a weight sensing floor  86  similar in manner to the leaf spring  60  ( FIG. 3 ) described above. The switch  82  is coupled to the CPU  30  and operates similarly to the switch  62  ( FIG. 3 ). It will be appreciated that other devices may be used for creating weight induced movement within the shelves  50  or  80 . 
     FIG. 5A  illustrates a cross-sectional view of a slidable shelf  90  connected to a rail system  94  in accordance with another embodiment of the present invention. The rail system  94  allows the shelf  90  to slide within a larger cabinet or frame structure (not shown).  FIGS. 5B and 5C  illustrate further embodiments of the rail system  94 . As shown in  FIG. 5B , a helical coil  100  is connected to a support structure  102  and a base portion  104  of the rail system  94 . The base portion  104  is a stationary part (bottom rail) of the rail system  94 . A top rail (not shown) is slideably received by the base portion  104  and is attached to the shelf  90 . In one representative embodiment, the support structure  102  may be a cabinet. A horizontally sliding portion (not shown) of the rail system  94  supports the shelf  90  and is slideably received by the base portion  104 . A switch  120  is positioned between the base portion  104  and the structure  102 . The spring  100  and switch  120  operate similarly to those in the shelves  50  and  80  ( FIGS. 3 and 4 ). 
   As shown in  FIG. 5C , in another alternate embodiment, a leaf spring  110  may be used to support the base portion  104  with respect to the structure  102 . A switch  122  is positioned between the base portion  104  and structure  102 . The spring  110  and switch  122  operate similarly to those in the shelves  50  and  80  ( FIGS. 3 and 4 ). It will be appreciated that in further embodiments, the leaf and coil springs shown in  FIGS. 3-5  may be replaced with a variety of other resilient members, including, for example, rubber or other polymeric compressible members, hydraulic or pneumatic cylinders, or any other suitable resilient members. 
   As shown in  FIGS. 6 and 7 , switches operate by being depressed with lighter weight on a shelf. The rail structure can be configured to perform the same function. 
   While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not, limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.