Abstract:
A weighing system for use in retrofitting a pallet handling apparatus to provide weighing functionality. The system comprises a control unit and two fork units. The electronic control unit has a display, an electronic weight calculation controller, and at least one control switch. Each fork unit is for substitution with one fork of the pallet handling apparatus. Each fork unit comprises a rigid frame member having an elongated configuration, a plurality of load cells fixedly connected to the frame member, the load cells being disposed in laterally oriented pairs, and a fork member communicatively connected to the frame and engaging the load cells.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY 
   This application claims the benefit under 35 U.S.C. §119(e) of co-pending U.S. Provisional Patent Application Ser. No. 60/526,423, filed Dec. 1, 2003, which is hereby incorporated by reference. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO A MICROFICHE APPENDIX, IF ANY 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates, generally, to weighing apparatus and methods. Particularly, the invention relates to pallet truck and pallet walkie scale apparatus and methods. Most particularly, the invention relates to an electronic scale retrofit system for an existing pallet walkie or lift truck. The invention may apply to other apparatus and methods. 
   2. Background Information 
   The state of the art includes the PW800™ pallet truck scale, which integrates a weigh scale into a lift truck and is provided by Intercomp Company of Minneapolis, Minn. USA. Intercomp Company has also disclosed electronic weigh scales systems and components in the following U.S. Pat. Nos. 5,228,527; 5,232,064; 5,646,376; and 5,894,112. 
   Lift trucks or “walkies” are hand movable forks which are used to move pallets of material in various commercial and industrial settings. A large number of walkies exist without a scale. A need is believed to exists for the present invention to add a weigh scale to such existing walkies. 
   All U.S. patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention provides a walkie retrofit apparatus and method which is practical, reliable, accurate and efficient, and which is believed to fulfil the need and to constitute an improvement over the background technology. 
   The system transforms an existing pallet truck, walkie or lift truck, including class II, III, IV and bar mount carriages, into a mobile weighing station. It can be used on standard 48 inch single pallet and 96 inch double pallet apparatus, with capacities up to 10,000 lbs. Power is supplied from the walkie&#39;s existing power pack without appreciably reducing overall run time. It can be configured for bar code scanning, data printout and RF wireless capabilities. 
   The invention enables fast and accurate weighing during movement of a pallet. This maximizes efficiency and minimizes guesswork in shipping, receiving, manufacturing, and other materials handling environments. Specifically, it an added process step and reliance on centralized stationary scales. Time is saved and accountability is improved. 
   In a general aspect the invention provides a weighing apparatus for a pallet handling apparatus, comprising a frame member, at least one load cell connected to the frame member, and a fork member communicatively connected to the frame and engaging the at least one load cell. 
   In a more specific aspect, the invention provides a weighing system for use in retrofitting a pallet handling apparatus to provide weighing functionality. The system comprises a control unit and two fork units. The electronic control unit has a display, an electronic weight calculation controller, and at least one control switch. Each fork unit is for substitution with one fork of the pallet handling apparatus. Each fork unit comprises a rigid frame member having an elongated configuration, a plurality of load cells fixedly connected to the frame member, the load cells being disposed in laterally oriented pairs, and a fork member communicatively connected to the frame and engaging the load cells. 
   The features, benefits and objects of the invention will become clear to those skilled in the art by reference to the following description, claims, and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates an embodiment of the electronic weigh scale system of the invention. 
       FIG. 2  further illustrates the system. 
       FIG. 3  is a perspective view of an embodiment of a false fork member of an embodiment of a retrofit scale assembly of the invention. 
       FIG. 4  is a perspective view of an embodiment of a frame member of the retrofit scale assembly. 
       FIG. 5  is a further perspective view of the frame member. 
       FIG. 6  is another perspective view of the frame member. 
       FIG. 7  is a top view of the frame member. 
       FIG. 8  is a side view of the frame member. 
       FIG. 9  is an end view of the frame member. 
       FIG. 10  is a detailed view of a portion of the end view of  FIG. 9 . 
       FIG. 11  is a perspective view of the false fork member. 
       FIG. 12  is a top view of the false fork member. 
       FIG. 13  is a side view of the false fork member. 
       FIG. 14  is an end view of the false fork member. 
       FIG. 15  is a perspective view of an embodiment of a fork back member of the retrofit scale assembly. 
       FIG. 16  is a side view of the fork back member. 
       FIG. 17  is a front view of the fork back member. 
       FIG. 18  is a perspective view of a push rod of the retrofit scale assembly. 
       FIG. 19  is a top view of the push rod. 
       FIG. 20  is a side view of the push rod. 
       FIG. 21  is perspective view of a summing box of the retrofit scale assembly. 
       FIG. 22  is an end view of the summing box. 
       FIG. 23  is a side view of the summing box. 
       FIG. 24  is a top or front view of the summing box. 
       FIG. 25  is a perspective view of an alternative embodiment of the retrofit scale assembly frame. 
       FIG. 26  is a bottom view of the frame of  FIG. 25 . 
       FIG. 27  is a side view of the frame of  FIG. 25 . 
       FIG. 28  is an end view of the frame of  FIG. 25 . 
       FIG. 29  is a detailed view of  FIG. 28 . 
       FIG. 30  is a perspective view of the top plate member of the frame of  FIG. 25 . 
       FIG. 31  is another perspective view of the top plate member of  FIG. 30 . 
       FIG. 32  is a side view of the top plate member of  FIG. 30 . 
       FIG. 33  is a top view of the top plate member of  FIG. 30 . 
       FIG. 34  is an end view of the top plate member of  FIG. 30 . 
       FIG. 35  is a perspective view of another embodiment of the frame member. 
       FIG. 36  is another perspective view of the frame member shown in  FIG. 35 . 
       FIG. 37  is a top view of the frame member. 
       FIG. 38  is a side view of the frame member. 
       FIG. 39  is a bottom view of the frame member. 
       FIG. 40  is an end view of the frame member. 
       FIG. 41  is a detailed view of the frame member shown in  FIG. 40 . 
       FIG. 42  is a perspective view of yet another embodiment of the frame member. 
       FIG. 43  is another perspective view of the frame member shown in  FIG. 42 . 
       FIG. 44  is a top view of the frame member of  FIG. 42 . 
       FIG. 45  is an end view of the frame member. 
       FIG. 46  is a bottom view of the frame member. 
       FIG. 47  is an end view of the frame member. 
       FIG. 48  is a detailed view of the frame member shown in  FIG. 47 . 
       FIG. 49  illustrates an embodiment of a control panel of the system of the invention. 
   

   DETAILED DESCRIPTION 
   The present invention provides embodiments of an electronic weigh scale retrofit system and method for a pallet truck, walkie or lift truck. It enables a quick and effective retrofit of an existing pallet device, for example a 48 inch single pallet walkie or a 96 inch double pallet walkie. Power is supplied from the walkie&#39;s existing power pack. The system can be configured for 12, 24 or 48 VDC. The system can be configured for various capacities, fork lengths and widths, and heights, lifting heights, and pallet apparatus accessories. Exemplary weighing capacities include, but are not limited to 10,000 pounds. 
     FIGS. 1 and 2  show an embodiment of the retrofit weigh scale system  10  of the present invention operatively connected to an electric walkie  15 . 
   Referring to  FIGS. 3 and 4 , an embodiment  20  of the retrofit scale system comprises a pair of fork/scale unit  20  (one associated with each fork of the pallet apparatus), each of which comprises a horizontally disposed frame or frame member  22 , a fork member or false fork  24  disposed parallel to the frame  22 , and a vertically disposed fork back  26  connected to the proximal or back end of the false fork  24 . At least one electronic load cell  28 , in this case six (6) are connected to the frame  22 . The connection is preferably made by flat socket head cap screws  30   a,b , socket head cap screw  32 , load cell spacer  34 , spherical washers  36   a,b , and nuts  38 . This assembly is constructed and arranged to permit the fork to move vertically a small amount, for example about 0.125 inches in this embodiment. Aperture  40  permits extension of the pallet device fork wheel (not shown). The load cells  28  are electronically communicatively connected to a control system  42 . The load cells  28  convert mechanical force received from the contents of the pallet (not shown) disposed on the false fork  24  to electrical signals, which are transmitted to the control system  42  to yield an equivalent weight value. The load cell  28  configuration receives sensitive vertically oriented forces which are the result of the pallet load, but is relatively insolated from horizontal forces caused by bumping, jarring, starting, stopping and other movement associated with pallet transportation. 
   Referring to  FIGS. 5-10 , the length and width of the frame  22  is dependent upon the dimensions of the pallet device fork which it is substituted for. This embodiment of the frame  22  comprises a pair of rear or proximal top plates  50 , a long, central top plate  52 , and a short, distal top plate  54 . The rigid, preferably metal plates are connected to proximal, long bottom straps  56  and distal, short bottom straps  58  as shown. Outside strap  60  is connected to the bottom straps  56  and  58 . Long, proximal inside straps  62  and short, distal inside straps  64  are also connected to the bottom straps  56  and  58 . Subplates  66  are preferably disposed under proximal top plates  50 . Pivot supports  68  are connected to the outside strap  60 . Pivot blocks  70  are connected to the pivot supports  68 . Angle supports  72  are disposed about aperture  74 . This assembly yields a strong, rigid frame  22  structure. 
     FIGS. 11-14  show the rigid, elongated structure of a false fork  24 . The length, width, and height of the false fork  24  is variable depending upon the dimensions of the frame  22 . 
     FIGS. 15-17  show the structure of the fork back  26 . Preferably, the back  26  comprises a frame center member  80 , a frame side member  82  and a frame bottom member  84 . 
     FIGS. 19-20  show an embodiment of a push rod  90 . 
     FIGS. 21-24  show an embodiment of a summing box  92 . The summing box  92  securely holds and protects electronic summing hardware (not shown) which is communicatively connected to each load cell  28  and to the pallet apparatus power supply. 
     FIGS. 25-29  show an alternative embodiment of the retrofit scale assembly frame  122 , for use with dual wheel pallet devices, comprising a top plate  124 , proximal bottom straps  126 , proximal inside straps  128 , distal bottom straps  130  and distal inside straps  132 . The configuration of the top plate  124  is further shown in  FIGS. 30-34 . 
     FIGS. 35-41  show another embodiment of the frame member  222  comprising a top plate  224 , proximal, middle and distal top plate under supports  226 ,  228  and  230 , pivot side straps  232 , pivot axle supports  234 , distal under supports  236  and distal top plates  238 . 
     FIGS. 42-48  show another embodiment of the frame member  322 . 
     FIG. 49  shows an embodiment of a control panel  400  of the system including a display  402  and a plurality of self explanatory control buttons, the general function of which is described below: 
   ON/OFF
         Press and hold this button 1 second to turn the scale on and off. The scale tests itself; when this test is completed successfully the system begins weighing. The product I.D. and software version number are display for a couple seconds upon power up. The number on the left is the product ID and the number on the right is the software version number.       

   NUMERIC KEYPAD
         Many operations require the operator to enter a number. The 10-key numeric keypad is used to enter numbers. These keys also have specific functions (as labeled) when the scale is in normal weighing mode.       

   ENTER
         Press the ENTER key after entering a number.       

   CLEAR
         If operator want to clear the number displayed (while in the process of entering a number), press the Clear key.       

   ZERO
         Tells the scale to display zero weight. This button is used any time the scale shows a non-zero value with no weight on the load cell. If operator press ZERO with weight on the load cell, that weight becomes the zero condition for the scale. This can be useful to cancel the weight of any weighing fixtures, such as barrels or boxes. When this weight is removed, a negative number is displayed until the system is re-zeroed. The ‘zero’ command will be delayed any time a change in weight is detected. While the scale is stabilizing, the display will show “-0-”. If there is continuous motion for about 15 seconds, the zero command will be rejected and the scale will return to normal weighing.       

   AZT (Auto Zero Tracking)
         This system contains a feature called Auto Zero Tracking (AZT), which corrects slight zero changes during normal operation. If small weights are added while the display is at or near zero, the scale may zero them off.       

   PRINT
         Press PRINT after operator have the displayed weight on the SYSTEM and wish to send the information to operator system/device.       

   NET/GROSS
         Toggles the readout between net weight and gross weight. Net weight applies only when there is a tare set. The indicator on the left side shows if the SYSTEM is displaying gross or net weight.
 
Net=Gross−Tare
       

   TARE
         Use this button to read a tare weight into memory. This tare weight will be subtracted from the gross weight, giving operator the net weight. This is useful for canceling the weight of a container used in weighing. A segment in the lower left corner of the display shows that the net weight is being calculated. Operator may press the TARE SET/DISPLAY button to show the tare weight anytime the scale is in net mode; the tare weight will show while operator press the button. To clear the tare press the TARE and CLEAR keys simultaneously. Tare does not function in pieces unit.       

   PRESET TARE
         Pressing the PRESET TARE key will bring up a screen that allows the user to enter a tare value. Enter the tare value using the numeric keypad and then press ENTER. To clear the tare press the TARE and CLEAR keys simultaneously.       

   UNITS/PIECES
         Toggles the weighing system between pound (English), and kilogram (SI metric), and ‘pieces’ (quantity of items) units of measure. When operator press this switch, the systems witches to the nearest comparable value in the selected system. The current unit of measure is shown by indicator segments on the left side of the main display.       

   SAMPLE
         Sample is used to so operator can view the weight in pieces. Place a number of items on the scale. A good rule of thumb is to place 3%-5% of the total number of pieces operator intend to weigh. With a known quantity of items on the scale press the SAMPLE key. Enter the number of items on the scale. The sample measurement is saved in the scale&#39;s memory. The scale will switch to the unit ‘pieces’ and display the number of pieces on the scale. To clear the sample measurement saved in memory, press the SAMPLE and CLEAR keys simultaneously.       

   APW
         APW is the abbreviation of Average Piece Weight. Press the APW key. Enter the average weight of one piece. The scale switches to ‘pieces’ unit and displays the number of pieces on the scale. To clear the APW press the APW and CLEAR keys simultaneously. If operator need to enter piece weights less than 1 lb. or 1 kg, see the APW decimal position section in ‘Calibration’. This can setup the SYSTEM to record APW&#39;s by tenths (1 decimal place) or by hundredths (2 decimal places).       

   TOTAL
         This function is used to record an accumulated total. When operator press the TOTAL key, the weight that is to be added to the accumulated total will blink for about 5 seconds. To add this to the total, press the TOTAL key again before the value stops blinking. The accumulated total will be displayed for about 2 seconds and return to the previous weighing mode.   If operator just want to view the total, press and hold the TOTAL key for about 3 seconds. The weight will be displayed until operator release the key. To clear the accumulated total, press the TOTAL and CLEAR keys simultaneously.       

   PEAK HOLD
         The peak hold feature will remember the maximum weight applied. While in peak mode it will not display any weight less than the maximum weight. To turn on the peak mode press PEAK, to turn off the peak mode press PEAK again. The peak indicator will be blinking if in peak mode. To clear the current peak weight press the ZERO key.       

   SET POINT 1
         This is an optional feature that allows for an external set point. When the specified weight (set point) is reached, a logic level high will be on the set point connection. Setpoints are used with some other device (e.g. alarm, relay) in conjunction to the SYSTEM. To activate a set point press the Set Point 1 (or Set Point 2) key. Enter the weight operator wants the set point to activate.       

   SET POINT 2
         Operates the same as Set Point 1.       

   The descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with an embodiment or embodiments thereof, it should be understood by those skilled in the art that there may be other embodiments which fall within the scope of the invention as defined by the claims. Where a claim, if any, is expressed as a means or step for performing a specified function it is intended that such claim be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof, including both structural equivalents and equivalent structures, material-based equivalents and equivalent materials, and act-based equivalents and equivalent acts.