Abstract:
The present invention is directed to a weight scale having a balance control system that detects unequal load distribution to the scale&#39;s load sensors and produces an output signal that enables the user to re-distribute weight until a predetermined level of balance is achieved. Various load sensors are positioned in an array in the scale and are in communication with a controller that receives signals from the sensors indicative of relative load applied to each sensor. The controller generates a signal that is displayed or emitted to the user indicative of the position of the user&#39;s center of gravity relative to the sensors.

Description:
This application is a continuation-in-part of Ser. No. 10/308.993 filed Dec. 2, 2002. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to weight scales. More particularly, the present invention relates to a weight position sensor system. The weight position sensor system has a balance control system that detects load distribution on the scale and provides an output signal to a user to indicate whether or not the user should re-position or shift weight in order to more equally distribute load and, thus, optimize scale accuracy. 
   2. Description of Related Art 
   Various known weight scales generally provide an upper platform for the user to stand on, having load detection cells positioned beneath the scales. The load from the weight of the user is transmitted from the platform to the load detection cells, which are mounted to a base. The load on the cells is measured by the cells and communicated to a controller, which causes an output display of the user&#39;s weight. The load detection cells are usually positioned in an evenly spaced array in an effort to position them where the load of the user is likely to be evenly distributed. This requires anticipation of precisely where the user is likely to stand on the scale and of how the user will distribute his or her weight in terms of distribution between front and back of the foot as well as right-vs.-left foot. The resultant scale reading is sometimes inaccurate because each user may stand on the scale in a different position and with different weight distribution, and each user has different size feet. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a weight position sensor system. 
   It is another object of the present invention to provide a weight position sensor system that has a balance control system that detects load distribution on the scale. 
   It is still another object of the present invention to provide a weight position sensor system that has an output signal to a user to indicate whether or not the user should re-position or shift weight in order to more equally distribute load. 
   It is a further object of the present invention to provide a weight position sensor system that has optimum scale accuracy. 
   These and other object and advantages of the present invention are achieved by a weight scale having a weight position sensor system. The weight position sensor system has a balance control system that detects unequal load distribution to the scale&#39;s load cells and produces an output signal that enables the user to re-distribute weight until a predetermined level of balance is achieved. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic, perspective view of a weight scale according to the present invention. 
       FIG. 2  is a schematic diagram of a balance control system for weight scales according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , there is provided a weight scale generally represented by reference numeral  10 . Weight scale  10  includes an upper platform or weight supporting surface  12 , a base  14  adapted to receive the platform, a display screen  16  preferably visible through the platform, and a plurality of load detection cells or sensors  18  (shown in phantom) positioned between the platform and the base. The cells  18  are mounted between the platform  12  and the base  14  in such a way that the load of the user&#39;s weight on the platform will be transmitted directly to the cells, as is generally known in the art. 
   The cells  18  may be of the type generally known in the art, which generally include a deflectable member (not shown) through which electric current is passed. When the deflectable member flexes under load applied to the platform  12 , it resistance properties are altered, and the change is monitored by measuring current flow. This is translated into a weight reading displayed to the user on the display screen  16 . Each load cell  18  is preferably a strain gauge. Such strain gauges are known in the art. In the preferred embodiment, there are four load cells that are applied one to each corner of the upper platform  12  thereby forming a generally rectangular pattern. 
   The upper platform or surface  12  is made of any material that permits any weight thereon to be directly transmitted to the cells  18 . The upper platform  12  can be made of plastic, metal, glass or other suitable material that can hold the weight of the user without breaking. Preferably, the upper surface  12  is made of plastic. 
   The base  14  is made of any material. Preferably, the base  14  is made of a material that protects the cells  18  from moisture or other undesired environmental effects that could adversely affect the performance of the cells. Accordingly, the cells  18  are preferably made of ceramic or plastic. 
   The scale  10  has a plurality of feet (not shown). Preferably, each foot is positioned in a corner of the scale  10 . Each load cell  18  is located directly above a different foot. Each foot is movable relative to the upper platform  12 . 
     FIG. 2  shows a schematic diagram of a balance control system  20  for the weight scale  10  according to a preferred embodiment of the present invention. The balance control system  20  shows four load detections cells  18 . A computer controller  21  of the type generally known, communicates with the cells  18  to process load signals from each cell, compare the signals from each cell, and provide an output signal that results from the comparison of each load signal, to the display screen  16  that indicates to the user whether or not the user&#39;s weight is evenly distributed. 
   In the preferred embodiment shown in  FIG. 1 , the load detection cells  18  are arranged in a uniform or evenly spaced, square configuration about the platform  12  such that if a user stands so that his/her center of gravity is in the center of the platform, and thus the center of the load detection cells, the load caused by the user&#39;s weight will be equally distributed and supported by each of the four load detection cells  18  so that the scale  10  will have equal load or weight distribution. It is understood that any number of cells  18  may be used, including only one cell. The cells  18  may be positioned in any pattern between the platform  12  and the base  14 . Preferably, the cells  18  are positioned in a symmetrically pattern about the geometry or configuration of the platform  12  (and base  14 ) so that it is easier to measure an unequal distribution on the platform. 
   Various types of display including one or more audible signals may be used to indicate to the user whether or not a state of equal weight distribution, or balance, is present. In the preferred embodiment shown in  FIG. 2 , a balance display  22  may be included in or separate from the display screen  16 . However, the balance display  22  is operatively connected to the display screen  16  and, thus, a computer controller  21 , so that the balance display communicates with the computer controller. In an alternative embodiment, the computer controller  21  can be operatively directly connected to the balance display  22 . 
   The balance display  22  may include a central light or diamond  26  and an array of lights  24 . Preferably, the array of lights  24  is arranged symmetrically about the central light. 
   When the user stands on the platform  12 , the lights on the balance display  22  light up in an array indicative of the user&#39;s position with respect to the center of gravity. For example, if the user&#39;s weight is centered with respect to the four cells  18 , only the central light  26  will be lit. If the user is leaning or standing too much to the right, both lights  24  to the right hand side of the central light  26  will light up. As the user leans or stands more to the left, only the single light directly to the right of the central light  26  will light up, thus indicating that the user&#39;s weight is shifted more toward the center. When the user finally shifts his weight to the center, only the central light  26  is lit. In a preferred embodiment, arrows are used as the indicators to show that weight needs to be shifted to, for example, the right and to the top of scale  10 . A shifting weight in the direction of the arrows until only the center light or diamond  26  lights, thus indicates the ideal balance for actuate and repeated weight measurement. Thus, the indications of the balance display  22  is achieved by the cells sending a signal or communicating to the controller  21  that in turn sends one or more signals that result in displays of indicated movement or shifting to the balance display. Accordingly, the cells  18  are preferably in a symmetrical or balanced (equally spaced apart pattern) pattern about the configuration of platform  12  to more precisely detect each variation of weight distribution. 
   Different balance indicators can be used in place of the precise embodiment described above. For instance, a different array of lights can be used, and the lighting or un-lighting sequences can be reversed depending on preference. Another way of indicating balance is to provide an audible signal that signals when the user&#39;s weight is centered, when it is not, and/or to which direction the user should re-position to achieve balance. 
   Operation of the above-described preferred embodiment will now be described. Initially, when the scale  10  is at rest, the scale is not powered. When the user desires to use the scale  10 , the user merely taps the platform  12 . Tapping the platform  12  loads the cells  18  and sends a communication to the controller  21  to initiate power-on switch  28  of the type generally known, which activates a power source  30 , such as a battery-powered pack. Alternatively, a manually activated power-on switch (not shown) may be provided for hand manipulation or toe-touch manipulation. After the scale  10  is powered on, the scale performs a self-zeroing routine as may be known in various existing scales. The self-zeroing routine generally signals to the controller  21  that in the instant condition, the weight output on the display screen  16  is zero. The self-zeroing operation is disclosed in a U.S. application that has been filed on Dec. 2, 2003 by the applicant of the present invention. This application is incorporated herein by reference. 
   Once the scale  10  has self-zeroed, the scale is now ready for the user to stand on the scale. The user then steps onto the scale  10 . The balance display  22  responds to the position of the user&#39;s center of gravity by lighting up accordingly, as described above, prompting the user to re-position or shift until the central light  26  illuminates. Optionally, the controller  21  may be programmed to not display the user&#39;s weight, thus displaying a blank screen or remaining at “0”, until the controller has indicated that the user&#39;s weight is centered. In lieu of, or in combination with, the visual signal, an audible signal may be produced by an audible output generator  32  that indicates relative position of the center of gravity and/or a balanced condition. 
   When the user&#39;s weight is sufficiently centered with respect to the load detection cells  18 , the balance display  22  will indicate the balanced condition. A signal indicating that balance is achieved will prompt the controller  21  to activate the display screen  16  to display the user&#39;s weight in pounds or kilograms. When the user steps off of the scale  10 , the controller  21  activates a time-out sequence to power-off the scale after a predetermined period. When the scale  10  is tapped again, the operational procedure repeats. 
   The scale  10  may be provided with additional features such as a display clock and calendar, a radio and/or audible signaling device, and programmable sounds. 
   While the preferred embodiment has been herein described, it is understood that various modifications can be made without departing from the scope of the present invention.