Abstract:
A mobile weighing apparatus in the form of a wheeled support structure (e.g., a wheelchair, wheeled bed, gurney, cart, motorized truck, etc.) that is especially adapted to weighing a human being supported by said apparatus. The apparatus employs a plurality of load cells that are respectively attached to a plurality of vertical support elements of said apparatus. Signals from each load cell are routed to a microprocessor which processes the signals and displays the weight carried on the apparatus.

Description:
FIELD OF THE INVENTION 
     This invention generally relates to weighing apparatus. More particularly, it relates to mobile weighing apparatus that are especially well suited for weighing incapacitated human beings. 
     BACKGROUND OF THE INVENTION 
     Although scales are commonly available for weighing human beings who are ambulatory, it is sometimes difficult and/or cumbersome to weigh humans who are not ambulatory or who are otherwise incapacitated. For example, an incapacitated person in a wheelchair must be wheeled to a scale of the type commonly used to weigh people who can readily step up on such a scale. Then the incapacitated person must be moved to an unsupported standing position on the scale in order to get a reasonably accurate weight measurement. The incapacitated person then must be safely returned to the wheelchair. If the person cannot stand, this weighing procedure is not feasible. 
     Weighing a severely incapacitated person who is generally confined to a bed, gurney, etc. is an even more difficult task because it generally requires that the incapacitated person be greatly assisted in getting out of, and back into, the bed, gurney, etc. Indeed, in some cases, a sling may be needed to lift a severely incapacitated person out of a bed or gurney for such a weighing. Such a person then may need to be vertically supported in a standing position on a scale. To the extent that vertical support is rendered to that severely incapacitated person, the weight reading is “falsified”. 
     It also is possible to weigh a person who is confined to a wheeled apparatus such as a wheelchair, wheeled bed, gurney, cart and the like by rolling the wheeled apparatus, and the person on it, upon a scale adapted for receiving such a wheeled apparatus. The total combined weight of the person and the wheeled apparatus is thus obtained. At some point in time, it also is necessary to weigh the wheeled apparatus (e.g., a wheelchair) alone in order to subtract the weight of that apparatus from the combined weight of the person (and his or her clothing, bedding, etc.) and the wheeled apparatus. This weighing procedure does not greatly disturb the incapacitated person, but it does require a special type of scale that is not commonly available—and rather expensive. 
     In short, all of these procedures for weighing incapacitated people are difficult, not well suited to giving accurate weight readings and/or require specialized, expensive, scales. Use of some of these weighing procedures also involves risk of injury to the incapacitated person and/or those attending such a person whenever the incapacitated person is removed from, and returned to, a wheelchair, wheeled bed, gurney, etc. 
     SUMMARY OF THE INVENTION 
     The present invention provides mobile weighing apparatus that enable a wheeled support structure such as a wheelchair, wheeled bed, gurney, cart, etc. to also serve as a scale for weighing an object carried by that wheeled structure. The object weighed by applicant&#39;s apparatus may be inanimate or animate in nature. For example, the mobile weighing apparatus of this invention might be a cart upon which commercial goods of virtually any kind may be weighed and transported. The mobile weighing apparatus of this invention are however especially useful in medical care situations because the weight of an incapacitated person in a wheelchair, wheeled bed, gurney, cart and the like can be easily determined without requiring the incapacitated person to get out of the mobile weighing device, step up on a scale and come to an unsupported, standing position. 
     This invention achieves these weighing objectives by connecting a load cell to each of a plurality of load-bearing, substantially vertical, support elements of a mobile weighing apparatus. A plurality of load cell-generated electrical signals are routed to, and processed by, a microprocessor which, after making appropriate computations, displays the weight of an object on the mobile weighing device. To this end, the mobile weighing apparatus of this patent disclosure will generally comprise: (1) a frame that includes a plurality of load-bearing, substantially vertical, support elements; (2) a plurality of wheels carried on axles attached to the frame; (3) a plurality of load cells that are respectively connected to each of a certain number of the plurality of load-bearing, substantially vertical, support elements (e.g., connection of each respective load cells to at least two, preferably three, and most preferably four, load-bearing, substantially vertical, support elements of the frame is highly preferred); and (4) a microprocessor that is electrically connected to each load cell in the plurality of load cells and which is capable of processing electrical signals from each load cell in a manner such that it determines the weight of an object (and especially a human being) carried by the mobile weighing apparatus and then displays that weight. Again, the frame of applicant&#39;s mobile weighing apparatus may define any number of vehicle types e.g., a wheelchair, a wheeled bed, a gurney, a cart, etc. Indeed, the mobile weighing apparatus of this patent disclosure may even be a motorized vehicle such as an electrically powered wheelchair. 
     In one preferred embodiment of this invention, the mobile weighing apparatus will constitute a wheelchair comprising: (1) a frame having (i) at least two, opposing, right front, load-bearing, substantially vertical, support elements, (ii) at least two, opposing, left front, load-bearing, substantially vertical, support elements, (iii) at least two, opposing, right rear, load-bearing, substantially vertical, support elements and (iv) at least two, opposing, left rear, load-bearing, substantially vertical, support elements, (2) a right front wheel that is rotatably mounted on the frame; (3) a left front wheel that is rotatably mounted on the frame; (4) a right rear wheel that is rotatably mounted on the frame; (5) a left rear wheel that is rotatably mounted on the frame; (6) a load cell connected to the at least two, opposing, right front, load-bearing, substantially vertical, support elements; (7) a load cell connected to the at least two, opposing, left front, load-bearing, substantially vertical, support elements; (8) a load cell connected to the at least two, opposing, right rear, load-bearing, substantially vertical, support elements; (9) a load cell connected to the at least two, opposing, left rear, load-bearing, substantially vertical, support elements, and (10) a microprocessor that is electrically connected to each load cell and which is capable of processing electrical signals from each load cell in a manner such that it determines the weight of a person in the wheelchair and then displays that weight. 
     In another, particularly preferred, embodiment of this invention, the mobile weighing apparatus will constitute a wheelchair comprising: (1) a frame having (i) two, upper, right front, load-bearing, substantially vertical, support elements and two, opposing, lower, right front, load-bearing, substantially vertical, support elements, (ii) two, upper, left front, load-bearing, substantially vertical, support elements and two, opposing, lower, left front, load-bearing, substantially vertical support elements, (iii) an upper, right rear, loadbearing, substantially vertical, support element, an opposing, lower, right rear, load-bearing, substantially vertical, support element, (iv) an upper, left rear, load-bearing, substantially vertical, support element and (v) an opposing, lower, left rear, load-bearing, substantially vertical, support element; (2) a right front wheel that is rotatably mounted to the frame; (3) a left front wheel that is rotatably mounted to the frame; (4) a right rear wheel rotatably mounted to the frame; (5) a left rear wheel rotatably mounted to the frame; (6) a load cell connected to each of the two, upper, right front, load-bearing, substantially vertical, support elements and to each of the two, opposing, lower, right front, substantially vertical support elements; (7) a load cell connected to each of the two, upper, left front, load-bearing, substantially vertical, support elements and to each of the two, opposing, lower, left front, substantially vertical, support elements; (8) a load cell connected to the upper, right rear, load-bearing, substantially vertical, support element and to the opposing, lower, right rear, load-bearing, substantially vertical, support element; (9) a load cell connected to the upper, left rear, load-bearing, substantially vertical, support element and to the opposing, lower, left rear, load-bearing, substantially vertical, support element; and (10) a microprocessor that is electrically connected to each load cell and which is capable of processing electrical signals from each load cell in a manner such that it determines the weight of a person in the wheelchair and then displays that weight. 
     Other advantages and features of the mobile weighing apparatus of this invention will become more apparent from the following drawings and more detailed descriptions. Once again, a wheelchair will be used to further illustrate the mobile weighing apparatus of this patent disclosure, but it warrants repeating that the principles taught herein can be applied to other kinds of mobile weighing apparatus as well. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a wheelchair made according to the teachings of this patent disclosure wherein said wheelchair includes a front load cell that is attached to two, opposing, load-bearing, substantially vertical, support elements. 
     FIG. 2 is an enlarged, cut-away, view of a load cell connected to two, opposing, load-bearing, substantially vertical, support elements in the manner generally shown in FIG.  1 . 
     FIG. 3 is an enlarged, cut-away, view of a load cell connected to three, load-bearing, elements, two of which are not truly vertical, but which still fall under applicant&#39;s hereinafter given definition of the term “substantially vertical”. 
     FIG. 4 is a side elevational view of a wheelchair made according to another embodiment of this patent disclosure wherein said wheelchair includes a front load cell that is connected to each of two upper, load-bearing, substantially vertical, support elements and likewise connected to each of two, opposing, lower, substantially vertical, support elements. 
     FIG. 5 is an enlarged, cut-away view of a load cell connected to two, upper, load-bearing, substantially vertical, support elements and two, opposing, lower, substantially vertical, support elements in the manner generally shown in FIG.  4 . 
     FIG. 6 is an enlarged, cut-away, view of a load cell connected to an upper, load-bearing, substantially vertical support element and a lower support element comprised of a tubular element bent in such a manner that it does not address the load cell at a truly vertical angle and which has extended level portion that supports the underside of a load cell. 
     FIG. 7 is an electrical circuit diagram of a representative load cell such as those shown in FIGS. 2,  3 ,  5  and  6 . 
     FIG. 8 a rear view of the wheelchair shown in FIG.  1 . 
     FIG. 9 shows a representative weight-indicating display that is electrically connected (e.g., by electrical wires) to a microprocessor that receives and processes electrical signals from the load cells. 
     FIG. 10 is a rear view of an alternative embodiment of this invention wherein a wheelchair is provided with three, load-bearing, substantially vertical, support elements (each comprised of a single upper element and a single lower element) and three wheels (rather than the four wheels shown in the mobile weighing apparatus depicted in FIG. 6) and wherein said three wheels are so adapted and arranged that a single front wheel can be used to steer the wheelchair. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a partially exploded, side elevational view of a wheelchair  10  generally constructed according to the teachings of this patent disclosure. The wheelchair  10  has an overall frame  12  comprised of various tubular elements  12 A,  12 B,  12 C,  12 D,  12 E,  12 F,  12 G,  12 H,  12 I, etc. This overall frame  12  includes a plurality of load-bearing, substantially vertical, support elements such as  12 B,  12 B′,  12 I,  12 E,  12 E′, etc. The frame  12  also includes certain substantially horizontal members, e.g., horizontal member  14 A, that serves to help support a seat  16  upon which a load such as a portion of the weight of an incapacitated human being (not shown) is placed. Ultimately, the overall frame  12  is supported by its load-bearing wheels&#39; contact with a ground or floor surface  17 . 
     FIG. 1 shows the wheelchair  10  provided with a relatively large, rear wheel  18 A and a relatively small, front wheel  20 A. As can be better seen in FIG. 8, a corresponding rear wheel  18 B and a corresponding front wheel  20 B are mounted on the opposite side of the wheelchair  12  depicted in FIG.  1 . Thus, observing this mobile weighing apparatus  10  from the rear (e.g., in the manner shown in FIG.  8 ), rear wheels  18 A and  18 B might be termed, respectively, the right rear wheel and the left rear wheel. This same “right/left” terminology can be applied to the front wheels  20 A (right) and  20 B (left) as well. A “left” horizontal member  14 B for supporting seat  16  also can be seen in FIG.  8 . 
     The wheelchair  10  shown in FIG. 1 is shown provided with a footrest  22 , an elbow rest  24  and a back rest  26 . The footrest  22  is shown mounted on a rotatable collar  28  that is mounted on front vertical support element  12 B in ways known to those skilled in the wheelchair manufacturing arts. So mounted, the footrest  22  constitutes another element of the overall frame  12 . FIG. 1 also generally indicates that the wheelchair  10  is provided with a microprocessor  34  that resides in a housing  36  having a weight display  38 . A representative wire  31 A( 15 ) leading from a load cell (e.g., leading from load cell  31 A as shown in FIG. 2) is depicted leading to the microprocessor  34  shown in FIG.  1 . 
     Load-bearing, substantially vertical, support elements  12 E,  12 E′,  12 B and  12 B′ of frame  12  are each shown mechanically connected to a respective load cell. For example, the top surface of load cell  30 A is shown mechanically connected to an upper, right rear, load-bearing, substantially vertical, support element  12 E. An opposing, lower, right rear, substantially vertical, support element  12 E′ is shown connected to the bottom surface of load cell  30 A. Via the structure of the overall frame  12 , support element  12 E′ is ultimately supported by wheel contact with the floor surface  17 . Thus, regardless of the magnitude of a downward force  32 A placed upon it, the lower, right rear, substantially vertical, support element  12 E′ will provide an, opposing, upward, force  32 A to any downward force  32 A′ placed on the load cell  30 A by the upper support element  12 E. Consequently, load cell  30 A will be compressed between downward force  32 A and upward force  32 A′. The resulting mechanical compression placed on the load cell  30 A by opposing forces  32 A and  32 A′ is detected and transduced by the load cell  30 A, in ways hereinafter more fully described, into an electrical signal (e.g., a voltage signal) that is sent to microprocessor unit  34 . 
     Similarly, a downward force placed on load cell  31 A by certain components of the weight of the wheelchair—and a person in it—is generally depicted by downward force direction arrow  32 B on the upper, right front vertical support element  12 B. In the general manner just discussed with respect to the downward force  32 A on load cell  30 A, the downward force  32 B on lead cell  31 A may be thought of as being opposed by an opposing or upward force  32 B′ placed on the bottom of load cell  31 A by a lower, right front, load-bearing, substantially vertical support element  12 B′ (here again, this upward force  32 B′ is ultimately provided by wheel contact with the ground  17 ). Thus, load cell  31 A likewise experiences a compression action when it is pressured between opposing forces  32 B and  32 B′. A strain on load cell  31 A resulting from these opposing compressive forces is likewise detected and transduced into an electrical signal which is sent to the microprocessor  34 . It also should be noted that the downward force  32 B placed on load cell  31 A need not necessarily be of the same magnitude as the downward force  32 A placed on load cell  30 A. Such differences are taken into account by a computer program that constitutes a part of the microprocessor  34 . 
     It might also be noted here that those forces placed on the overall frame  12  by various cantilevered force components, (e.g., for example, the cantilevered force component depicted by downward direction arrow  32 C (e.g., such as those resulting from the cantilevered weight of the wheelchair occupant&#39;s legs and feet) will, to some degree, become a component of the loads placed on the load cells of this mobile weighing apparatus  10 . This is especially true of those load cells, e.g., load cell  31 A, that are connected to a vertical support, e.g., vertical element  12 B, to which a cantilevered load such as that depicted by direction arrow  32 C is transferred. Be these cantilevered forces as they may, the microprocessor unit  34  can be programmed in ways known to those skilled in this art to deal with cantilevered force components, such as the one generally depicted in FIG. 1 by force direction arrow  32 C. 
     Methods of connecting load cells with load bearing, vertical support elements such as members  12 B and  12 B′ of applicant&#39;s overall frame  12  are well known to those skilled in making, mounting and using such load cells. However, for purposes of illustration, a variety of detailed representative vertical support element/load cell connections are given in FIGS. 2,  3 ,  5  and  6 . For example, FIG. 2 depicts, in exploded, cut-away detail, the load cell  31 A shown in FIG.  1 . This load cell  31 A has a top surface  31 A( 1 ), a bottom surface  31 A( 2 ), a left side surface  31 A( 3 ), a right side surface  31 A( 4 ), an outside face piece  31 A( 5 ) and an inside face piece  31 A( 6 ). The upper, load-bearing, vertical support element  12 B is shown in abutting mechanical connection with the top surface  31 A( 1 ) of load cell  31 A. For example the vertical support element  12 B can be welded, screwed or glued to the top surface  31 A( 1 ) of the load cell  31 A. A downward force or load placed on vertical support element  12 B is again depicted by downward force direction arrow  32 B. This downward force  32 B also is depicted as being transmitted as a continuum of downward vertical force components  32 B( 1 ),  32 B( 2 ), etc. over the outside face piece  31 A( 5 ) of the load cell  31 A. Such forces create a strain in the load cell which are detected and transduced into electrical signals. FIG. 2 also illustrates that vertical support element  12 B is preferably tubular in nature. Hence, it is shown provided with a hollow core region  12 B( 1 ) through which electrical connection wires, such as wire  31 A( 15 ), may be conveniently passed in order to electrically connect the load cell  31 A with the microprocessor  34  in the manner generally suggested in FIG.  1 . 
     Similarly, FIG. 2 depicts a lower, opposing, vertical support element  12 B′ in abutting contact with the bottom surface  31 A( 2 ) of load cell  31 A. Vertical support element  12 B′ is also shown provided with a hollow center region  12 B′ ( 1 ). The upward force carried by lower vertical support element  12 B′ is depicted by upward force direction arrow  32 B′. This force  32 B′ also is, in turn, depicted as being transmitted as a continuum of upward vertical force components  32 B′ ( 1 ),  32 B′ ( 2 ), etc. over the outside face piece  31 A( 5 ) of the load cell  31 A. Thus, the right face piece  31 A( 5 ) is subjected to a compression force between these downward forces and upward forces. 
     FIG. 2 also shows various strain gauge element attached (typically by gluing a flat face side of the strain gauge to a rear side  31 A( 5 )′ of the outside face piece  31 A( 5 ), of the load cell  31 A). A strain placed on the load cell—and particularly on its right rear side  31 A( 5 )—is detected by such strain gauge elements which, under compression, undergo strain and an accompanying change in the electrical resistivity of their strain gauge element(s). Again, it is this change in electrical resistivity that is detected and transduced into an electrical signal that is sent to the microprocessor  34 . 
     Those skilled in the arts of making and using load cells will appreciate that such load cells are generally comprised of an array of strain gauge elements, resistor elements and voltage detection elements. These elements are usually electrically connected in a Wheatstone bridge type circuit such as the one depicted in FIG.  7 . The representative circuit described in FIG. 7 also is shown, by way of example, as part of the load cell  31 A detailed in FIG.  2 . This representative circuit includes a series of strain gauges  31 A( 7 ),  31 A( 8 ),  31 A( 9 ) and  31 A( 10 ). Each of these strain gauges respectively has at least one strain detector element, e.g.,  31 A( 7 )′,  31 A( 8 )′,  31 A( 9 )′ and  31 A( 10 )′ whose function is to transduce the mechanical strain that it experiences into electrical signals. Preferably, all of these strain gauge elements are attached to the same vertical surface. For example, FIG. 2 depicts all of these strain gauge elements attached to the rear surface  31 A( 5 )′ of outside face piece  31 A( 5 ). In any case, these electrical signals are then further processed through use of resistor pattern elements such as those indicated by item numbers  31 A( 11 ) and  31 A( 12 ) in FIG.  2 . Such load cell circuits also typically include compensation resistor elements such as those depicted by item numbers  31 (a) 14  and  31 A( 17 ) . The electromotive force E o  produced by such a load cell circuit is also generally depicted by a voltage detection device  31 A( 16 ). The connector wires needed to create this load cell circuit are generally indicated by item number  31 A( 13 ) throughout the load cell circuit indicated in FIG.  2 . Once created and detected by such a load cell circuit, a resulting voltage can be transmitted, e.g., via line  31 A( 15 ), to the microprocessor  34 . 
     FIG. 3 depicts, in exploded, cut-away detail, a load cell  31 A that is very similar to the load cell  31 A shown in FIG.  2 . The only difference is the fact that the load cell  31 A shown in FIG. 3 is shown being supported by two support elements  12 B′ ( 1 ) and  12 B′ ( 2 ) rather than the single, lower, vertical support element  12 B′ shown in FIG.  2 . Thus, a vertical component  32 B′ ( 1 ) of the force carried by support element  12 ′ ( 1 ) and a vertical component  32 B′ ( 2 ) of the force carried by support element  12 B′ ( 2 ) each serve to support the load cell  31 A against any downward force (e.g., downward force  32 B) placed on the load cell via upper vertical support element  12 B. 
     FIG. 3 also shows that vertical support elements  12 B′ ( 1 ) and  12 B′ ( 2 ) each contact the bottom surface  31 A( 2 ) of the load cell  31 A at an angle θ, i.e., an angle θ relative to vertical line  12 B′ ( 3 ) or relative to vertical support line  12 B′ ( 4 ). Thus, support elements  12 B′ ( 1 ) and  12 B′ ( 2 ) are not truly “vertical”. Nonetheless, such elements can be used to mechanically support the load cells (e.g., load cell  31 A) of this invention and thereby create strain forces upon a load cell&#39;s strain gauge elements. Hence, for the purposes of this patent disclosure, the term “vertical” (e.g., as in the terms “vertical support element”, “substantially vertical support elements”, etc.) can be taken to mean a support element that is connected to a load cell at an angle from the vertical of 45° or less. In this regard, applicant also would note that use of truly vertical support elements (e.g., those whose angle θ of element connection to the load cell from a true vertical line such as vertical lines  12 B′ ( 3 ) and  12 B′ ( 4 ) in FIG. 3 is substantially zero degrees) are preferred; but that support elements (e.g.,  12 B′ ( 1 ) and  12 B′ ( 2 ) that address a bottom or top surface of the load cell at an angle of 45° or less can also be employed. 
     FIG. 4 is a side elevational view of a wheelchair made according to another teaching of this patent disclosure wherein said wheelchair includes a front load cell that is attached to each two, upper load-bearing, substantially vertical, support elements and two, opposing, lower, vertical support elements. 
     FIG. 5 is an enlarged, cut-away view of a load cell connected to two, upper, load-bearing, substantially vertical, support elements and to two, opposing, lower, vertical support elements in the manner shown in FIG.  4 . In FIG. 5, the load cell  31 A is shown compressed from above by two, upper, load-bearing, substantially vertical support elements  12 B and  12 B( 1 ). The load carried by vertical support element  12 B is depicted by force direction arrow  32 B. Vertical support element  12 B is shown provided with a core  12 B( 1 )′ through which a wire  31 A( 15 ) passes. The other, upper, vertical support element  12 B(l) carries a downward force  32 B and also is tubular in nature as indicated by its core  12 B( 1 )″. The lower, vertical support element that generally opposes the upper support element  12 B is designated  12 B′. It carries an opposing, upward, vertical force  32 B′ and is depicted with a core  12 B′ ( 1 )′. Similarly, lower, vertical support element  12 B′ ( 1 ) carries an upward force  32 B′ and has a core  12 B′ ( 1 )″. 
     FIG. 6 is an enlarged, cut-away view of a load cell whose underside is supported by a load-bearing, substantially vertical support element that is bent in a manner such that an extended portion of the tubular element abuts against, and hence supports, the bottom  31 A( 2 ) of load cell  31 A. In other words the lower support element  12 X is a bent tubular element having a left end  12 B′ ( 1 ) that approaches the bottom  31 A( 2 ) of the load cell  31 A at an angle θ and a right end  12 B′ ( 2 ) that approaches the bottom of the load cell at an angle θ′. 
     FIG. 7 shows a load cell circuit employing an array of strain gauges and resistor elements. For example, the strain gauges  31 A( 7 ),  31 A( 8 ),  31 A( 9 ) and  31 A( 10 ) shown in this circuit diagram are shown forming a part of a Wheatstone bridge circuit. Such Wheatstone bridge circuits serve to produce an electromotive force that is generally depicted as E o  in FIG.  2 . That is to say that a mechanical strain experienced by a load cell surface and detected by one or more strain gauge elements  31 A( 7 )′,  31 A( 8 )′, etc. are transduced into a voltage E o  that is detected and sent to the microprocessor unit  34 . 
     The more specific character and design criteria of such load cells are well known to those skilled in this art and are described in the appropriate literature. For example, they are described in a booklet entitled “Strain Gages, Bondable Resistors, Installation Accessories”, published by Micro-Measurement Division, Measurement Group, Inc., Raleigh, N.C. 27611. This booklet is incorporated herein by reference. Those skilled in the load cell manufacturing and application arts also will appreciate that these load cell circuits can be programmed to make various refinement computations, e.g., (1) zero balance calculations, (2) zero temperature shift calculations, (3) zero creep compensation calculations, etc. For example, a zero balance computation can be programmed into the microprocessor  34  to “subtract out” the weight of the wheelchair and display only the weight of the person in it. 
     FIG. 8 shows a rear view of a wheelchair  10  such as the one shown in FIG.  1 . FIG. 8 particularly illustrates that rear wheel  18 A can be mounted on its own axle  22 A and rear wheel  18 B can be mounted on its own axle  22 B. FIG. 8 also illustrates that axles  22 A and  22 B can be respectively mounted in a journal element of such load cells  30 A and  30 B. Similarly, front wheel  20 A is shown mounted to its own axle  24 A while front wheel  20 B is mounted to its own axle  24 B. FIG. 8 also illustrates that the frame  12  of such a wheelchair can be laterally folded through use of pivotally mounted cross support elements  12 F and  12 G by applying lateral forces F, F′, G and G′ in the manner generally suggested in FIG.  8 . 
     FIG. 9 shows a microprocessor housing  36  having a weight display window  38 . The housing  36  contains a microprocessor  34  (which is not actually shown) that is connected via lead wires  31 A( 15 ),  31 A( 15 ) ( 1 ),  31 A( 15 ) ( 2 ) and  31 A( 15 ) ( 3 ) to the microprocessor  34 . Thus, the microprocessor  34  can receive electrical voltage signals from each of the load cells  30 A,  30 B,  31 A,  31 B, etc. via these lead wires. The housing  36  is preferably rotatably mounted on a tubular vertical frame element (e.g., vertical frame element  12 E) so that the weight display  38  can be rotated and, hence, seen by the person in the wheelchair as well as by those attending to that person. To this end, the housing  36  can further comprise an arm element  40  whose wheelchair frame contacting end  42  is tubular in nature so that it can be rotatably mounted on a tubular vertical element  12 E of the frame  12 . Preferably this vertical element  12 E will end in a horizontal portion  44  to which a hand grip  46 A can be attached for the convenience of the person pushing the wheelchair  10 . 
     FIG. 10 depicts a mobile weighing device  10 ′ mounted on three wheels. In effect the wheelchair  10  shown in FIG. 1 has been modified such that the front of said wheelchair  10 ′ is supported on a single front wheel  48  mounted on a vertical support element  50  having prongs SOA and SOB which serve as a mounting for an axle  52  for the front wheel  48 . FIG. 10 also suggests that this front wheel  48  may be guided by a guide bar  54  which is operated by the wheelchair&#39;s occupant. Indeed, FIG. 10 further illustrates the case where a mobile weighing apparatus  10 ′ of this patent disclosure may be a motor vehicle such as one powered by an electric motor. That is to say that the mobile weighing apparatus of this patent disclosure may be provided with a power source such as a battery powered electrical motor  56  or a gasoline powered engine. 
     Those skilled in this art also will appreciate that while this invention generally has been described in terms of the general discussions, specific examples, drawings and preferred embodiments, none of these should be taken individually as a limitation upon the overall inventive concepts which are set forth in the following claims.