Folding digital scale

A portable digital scale is foldable for ease of storage and transport. The scale includes a fluid-filled elastomeric bladder and electronic module disposed in a hard-sided case that is opened in use and folded to encase the bladder and electronic module during transport and storage. The electronic module includes a pressure sensor for detecting the fluid pressure in the bladder as a measure of the user's weight, and a user interface and digital display for displaying the weight and/or other parameters requested by the user. Preferably, the electronic module includes a memory device capable of storing multiple weight measurements and a data port for down-loading stored weight data to a personal computer or PDA for tracking weight variation of one or more users over time.

TECHNICAL FIELD

The present invention relates to a digital scale for measuring a person's weight, and more particularly to a scale designed to be portable.

BACKGROUND OF THE INVENTION

The term digital scale as used herein refers to any electronic weighing device designed to support the weight of a standing person, and to indicate the person's weight on a digital display. A scale is generally considered to be portable if it is relatively small and lightweight, but even scales of this type are not particularly convenient to transport or store due to their size. Accordingly, what is needed is a digital scale that is designed for portability and storage.

SUMMARY OF THE INVENTION

The present invention is directed to an improved digital scale that is foldable to facilitate storage and transport. The scale includes a fluid-filled elastomeric bladder and electronic module disposed in a hard-sided case that is opened in use and folded to encase the bladder and electronic module during transport and storage. The electronic module includes a pressure sensor for detecting the fluid pressure in the bladder as a measure of weight applied to the scale, and a user interface and digital display for displaying the weight and/or other parameters requested by a user. Preferably, the electronic module includes a memory device capable of storing multiple weight measurements and a data port for down-loading stored weight data to a personal computer or PDA for tracking weight variation of one or more users over time.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 1,2and5, the reference numeral10generally designates a folding digital scale according to the present invention. The digital scale10comprises an electronic module12and three foldable layers14,16,18disposed in a foldable hard-sided case20. The scale10may be open for usage as illustrated inFIGS. 1–2or folded for storage and/or transport as illustrated inFIG. 5. An inwardly extending flange22of case20engages the marginal periphery of electronic module12and top layer18to retain the various components within the case20.

The case20may be formed of ABS or other strong but lightweight plastic, and includes an integral living hinge that allows the case halves20a,20bto lie flat against a floor or other flat surface when the case20is open as depicted inFIGS. 1–2. In the illustrated embodiment, the living hinge is implemented with a flexible polyurethane sheet24that spans the case halves20a,20b, and is preferably insert-molded with the case20.

The first or bottom layer14is a felt pad26that that rests on the floor28of case20. The felt pad26cushions the second or middle layer16, and protects it from damage due to pinching and the like. Materials other than felt may be used, but felt is preferred due to its low cost and light weight.

Referring toFIG. 4, the second or middle layer16is a fluid-filled elastomeric bladder30formed by joining upper and lower sheets of elastomeric material to form a closed volume, and then filling the closed volume with a suitable liquid such as silicone oil. The upper and lower elastomeric sheets are joined by an outer peripheral weld32, and an inner weld34divides the bladder30into left and right sides30a,30b. A pair of channels36a,36bdefined by the outer and inner welds32,34enable fluid communication between the left and right bladder sides30a,30b. The bladder material30cwithin the inner weld34may be removed if desired. Also, the upper and lower sheets of bladder30within the left and right sides30a,30bmay be joined by a pattern of spot welds38to prevent pooling of the bladder fluid. The right side30bof bladder30is undercut as shown to accommodate the electronic module12, and a fluid port42in the periphery of bladder30adjacent the location of electronic module12enables measurement of the fluid pressure within bladder30by a pressure sensor44of electronic module12as described below in reference toFIG. 3.

Referring toFIGS. 1–3, the electronic module12houses a digital (LCD or LED) display46, a pair of user interface switch inputs48, a pressure sensor44, a set of control and memory integrated circuit (IC) chips50,52mounted on a circuit board54, a serial data port56and a battery compartment58. The pressure sensor44is coupled to the fluid port42of bladder30by a pressure tube59, and a sensor output signal responsive to the fluid pressure in bladder30is coupled to control IC50via conductor traces on circuit board54. The control IC50determines a weight corresponding to the sensed fluid pressure (and possibly other factors such as temperature, etc.) and displays the weight on digital display46. The user switch inputs48can be used to select the displayed weight measurement units (i.e., metric or English) and to associate the weight with a user profile stored in memory IC52. When the user is not standing on the scale10, the user switch inputs48can be manipulated to display a stored weight history for a selected user, and the stored weight data can be downloaded from memory IC52to a personal computer or PDA via serial data port56.

The third or top layer18is a foldable polypropylene pad60that covers the bladder30. The pad60serves as an interface between the user (and footwear, if any) and the bladder30; it protects the bladder30from damage and helps distribute the user's weight. Foldability of the pad60can be facilitated by a living hinge of flexible material such as polyurethane bonded to the inboard face of pad60as shown.

In summary, the present invention provides a portable digital scale that is foldable for ease of stowing and transport. Foldability is enabled by using a fluid filled elastomeric bladder to measure weight, and the foldable outer case protects the bladder when the scale is not in use. While the present invention has been described with respect to the illustrated embodiment, it is recognized that numerous modifications and variations in addition to those mentioned herein will occur to those skilled in the art. Accordingly, it is intended that the invention not be limited to the disclosed embodiment, but that it have the full scope permitted by the language of the following claims.