JPS63210731A - Weight measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a weight measuring device. In particular, the invention relates to a device for determining the "weight" or "force" exerted by an object.

(Prior Art) Conventional weight measuring devices measure the linear strain (
For example, it uses a spring whose strain is proportional to the applied force, or it uses the strain of a block object measured using a strain gauge as a load cell.

(Problems to be Solved by the Invention) The disadvantages of these measurement methods are that fatigue of the springs and load cells
It introduces uncertainty that increases over time. Thermal expansion of the object further impairs accuracy, which cannot be predicted without a temperature measurement device.

Changes in the Earth's magnetic field and atmospheric pressure are additional sources of error in devices that require extremely high sensitivity and accuracy.

The purpose of the invention is to overcome the above-mentioned drawbacks of conventional weighing devices. Furthermore, it is an object of the present invention to provide a weight measuring device in which errors due to fatigue, changes in atmospheric pressure, changes in the earth's magnetic field, and changes in temperature can be significantly reduced.

(Means for Solving the Problems) According to the present invention, a device for measuring the weight of an object is provided as comprising the following components. (i) a measuring platform containing a flowing material, the measuring platform being arranged to receive the object such that the flowing material is subjected to a pressure related to the weight of the object; (ii) sensing means coupled to said flow material for generating a signal indicative of said pressure; (iii) a processing device for receiving said signal and generating an output related to the weight of the object; (iv) said A display device to display the output.

Conveniently, the measurement platform desirably comprises a substantially incompressible material.

Furthermore, it is preferable that this substance is isotropic.

The material shall be capable of undergoing a pressure that varies depending on the force or weight applied to the material. The material is contained in a non-stretchable container. The container may be visible; the container may be made of plastic; for example, the container may be made of a fairly thin (about the thickness of a bathroom mat) bag. ing.

This bag or container can be filled with a substance such as a liquid. This liquid may be water.

The object whose weight or force is to be measured may be adapted to act on the substance in any suitable manner.

The bag or container may include a substantially hard surface portion, which hard surface portion may be integrally molded with the bag or container or may be molded separately and then attached. .

This substantially rigid part can constitute a measuring plate in the aforementioned surface area. This measuring plate is preferably substantially rectangular, but may be rounded or of any other suitable shape. This measuring plate is preferably placed on the object to be measured. It is best to have a size and shape that can accommodate the whole body.

The pressure exerted on a flowable substance is determined based on the weight or force exerted by the object to be measured and the substantially hard surface area. This output pressure P- is given by the following equation.

(1) P=transport g/A+constant where the cocoon is the mass of the object, g is the gravitational acceleration, and A is the substantially hard surface portion or surface area of the measuring plate 1-. By simply changing the surface area of the measuring plate,
It can be understood from equation (1) that a specific pressure value can be obtained for any force or weight.

The pressure sensing means preferably comprises a pressure sensing device such as a pressure transducer, which may be coupled to the fluid material in any suitable manner. The pressure transducer may be composed of a device whose output resistance value changes according to the pressure applied to its sensing element. In one example, this sensing means may consist of a strain gauge. This strain gauge may be constructed of a semiconductor device that utilizes a piezoresistance effect. Alternatively, a pressure transducer may have an output capacitance that changes when pressure is applied.

The processing means may be provided in any suitable manner. Preferably,
The processing means includes a suitably programmed microprocessor or microcomputer. The processing means are adapted to calculate the force or weight exerted by the object.

The processing means may include means for clearing the device before commencing the reading operation. This clearing operation may be performed during an initial scan by the processing means.

The signal from the pressure sensing means may be directly input to the processing means, or may be input via infrared rays, radio waves, an extension lead wire, or other transmission means.

The processing means may include storage means for storing one or more previously read weights. The storage means may consist of digital memory. As an example, the storage means may consist of random access memory. The storage means is preferably non-volatile.

The processing means are programmed to operate in one or several modes. The operating mode can be selected via a keyboard interfaced with the processing means.

(i) Standard mode By using the relationship in equation (1) above, the processing means is able to calculate the mass (a+) of the object to be measured placed on the measurement platform. This mass can be expressed in kilograms or bonds. This weight indication takes place immediately when the load is placed on the measuring platform. In one example, the processing means The weight is displayed for a period of 20 seconds after the object has been removed, after which the processing means will return to idle mode.

(ii) Idle Mode When powered up, i.e. connected to a power source, the processing means places it into an idle mode of operation. The 'rh source can consist of an alkaline battery or a rechargeable battery. When entering the idle mode, the number "8" is displayed on all digits of the display means for several seconds. After that, the numbers on the keyboard)
All displays are blank until a key is pressed or a load is placed on the measurement platform. If even one number key is pressed, the processing means displays the number "8" in all digits. This is used as a test function. Since idle mode is a no-load condition, this mode can be used to automatically achieve O regulation while taking into account changes in the earth's magnetic field, changes in atmospheric pressure, changes in gravitational acceleration, and changes in temperature. Can be done.

(iii) Addition mode The addition mode can be selected using the keyboard. When this mode is selected, an appropriate sign is displayed on the display means. When the first load is placed on the measuring platform, <kg or bond) i! ! The weight will be displayed depending on your selection. The initial load is then removed from the measurement platform, thereby starting the summing mode.

The initial weight is stored in the storage means and the display remains unchanged.

A second load is then placed on the measurement platform.
i is placed. (Processing means are arranged to enter idle mode if this is not done within 20 seconds). Thereafter, the display means displays the sum of the first and second loads.

The processing means is arranged to return to the idle mode if no load is placed on the measurement platform within 20 seconds after selecting the addition mode by pressing a key. This addition mode is used for weighing luggage, etc.

(iv) Comparison mode: For example, selection can be made by pressing the button together with numbers O to 9 (in other words, the individual's code number).

This number is used to access historical memory for storing measurement results obtained at any point in the past.

After selecting the comparison mode, the load is placed on the measurement platform. (If this is not done within 20 seconds,
Processing measures are taken to put it in idle mode)
. The weight is displayed in the following way (in kg or bond). If the new weight is equal to or smaller than the old weight stored in the storage device, the processing means is configured to first display the new weight for 5 seconds and then display the old weight for 5 seconds. being done. This display is repeated as long as a new load is placed on the measurement platform. If the new weight is greater than the old weight stored in the storage device, processing is performed so that the new weight is displayed for 0.5 seconds and then a blank space is displayed for 0.5 seconds. Measures have been taken. This display continues for 5 seconds. The old weight is then displayed continuously for 5 seconds. This sequence is repeated as long as a new load is placed on the measurement platform.

(v) Accumulation Mode The accumulation mode is selected to actually perform a substantial metrological action. This mode is used, for example, to measure the weight of an infant. First the mother gets on the measuring platform,
The mother's weight is displayed.

After 5 seconds, the display becomes 0 even though the mother remains on the measurement platform.

Then, when the infant is handed over to the mother, only the infant's weight is displayed.

The accumulation mode may include storage for storing the infant's weight for future reference. The infant's past weight will be recalled and displayed.

Assume that as 1rIA, a new weight Jl (for example, body weight) and an old weight I are displayed alternately for 5 seconds each for a total of 20 seconds. Preferably, the new weight is displayed in flashing mode and the old weight is displayed in steady mode, and then the new weight is stored in the memory in place of the old weight. Thereafter, the processing means returns to idle mode.

The temperature sensing device may include temperature sensing means for sensing the ambient temperature and/or the temperature of the flowing material within the metering platform. The temperature sensing means are adapted to compensate for pressure fluctuations due to changes in ambient temperature. The temperature sensing means can be coupled to the processing means via a suitable interface. The temperature sensing means may be of any suitable type, ie, a thermistor, thermocouple, semiconductor junction, or the like.

The human length display means may be configured to display the weight or force exerted by the object being measured.The zero display means may be constructed of any suitable type. In one example, the display means comprises a digital display such as a liquid crystal or a light emitting diode. The device is adapted to display weight or force in any unit of measurement, such as kg or bonds. The device may include means for converting weight or force from one unit of measure to another.

The display means may be provided in close proximity to the device itself, or may be provided at a location separate from the main body of the device.

For example, when the weight measuring device of the present invention is used as a scale, the display means may be provided substantially at line-of-sight level so that the weighed value can be easily viewed.

The device of the present invention can be adapted to a wide variety of loads. Due to the configuration of the present invention, the device of the present invention can be manufactured with a relatively simple construction that cannot be achieved with existing devices. . Bulky mechanical equipment and load demands (l
The device according to the invention is also less susceptible to somewhat rough handling compared to existing devices. By employing information processing technology, it is possible to save time and effort in zero-adjusting the device. The precision of the device is maintained over a long period of time, which is unparalleled.

Embodiment The weight measuring device of FIG. 1 consists of a measuring platform 10 which can be operatively coupled to a pressure sensing means 11. The weighing device shown in FIG. The output of the pressure sensing means 11 is input to the processing means 12 via a suitable interface means. Processing means 1
The output of 2 is given to display means 14 via appropriate interface means 15. The storage means 16 is connected to the processing means 12 for data storage.

The preferred embodiment of the device, illustrated in FIG. 2, includes a measurement platform consisting of a liquid-filled container 20 and a substantially rigid measurement plate 21. This measurement plate 21 is rectangular with area A.

The pressure transducer 22 is housed in a fluid-filled container 20 such that the sensing element of the pressure transducer can communicate with the substance (fluid) within the container 20.

The output of pressure transducer 22 is coupled to microprocessor 23 via interface circuit 24. Interface circuit 24 includes an operational amplifier and a Wheatstone bridge, of which pressure transducer 22 forms one of the bridges. This interface circuit 24 includes one A-D converter. The output of the operational amplifier is input to this AD converter. The microprocessor 23 may also include an AD converter.

The microprocessor 23 calculates the weight or force exerted by the measurement object on the measurement plate (area A) by utilizing equation (1). The microprocessor 23 further includes the measurement platform 20
In addition, all nonlinearities existing in the pressure sensing means 22 are linearized.

The keyboard 25 has numeric and non-numeric keys,
It is connected to a microprocessor 23 for controlling the measuring device, ie mode selection, power on/off, etc.

A storage device 26 is coupled to the microprocessor for storing one or more weight or force measurements for later recall.

The output of microprocessor 23 is coupled to a digital display 28 via a suitable interface circuit 27. Digital displays can be constructed with liquid crystal or light emitting diode display segments.

The electronic circuits of the present invention can also be assembled into integrated circuits to reduce unit cost.

It will, of course, be envisaged that various changes, modifications and/or additions may be made to the arrangements and arrangements of components described herein without departing from the spirit and scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a weight measuring device according to the present invention. FIG. 2 is a block diagram of a preferred embodiment according to the present invention. 10...Measuring platform 11...Pressure detection means 12...Processing means 13...
- Interface means 14... Display means 15... Interface 16... Storage means 20... Measurement platform 21... Source fixing plate 22... Pressure transducer 23.
...Microprocessor 24...Interface circuit 25...Keyboard 26...Storage device 27...
...Interface circuit 28...Digital display device import...Object to be measured (5 others) Procedural amendment (c) July 27, 1988 Director General of the Patent Office Kunio Ogawa 2, Name of invention Weight n1 fixed device 3, relationship with the amended person case Applicant address name Appliance Control Systems (Holdinges) Proprietary Limited 4, agent address Otemachi, Chiyoda-ku, Tokyo 2-2-1 Shin-Otemachi Building Room 206. 5. Date of amendment order: April 28, 1985 (old shipping) 6. Subject of amendment

Claims (1)

Claims: 1. A measurement platform comprising a fluid material adapted to receive an object, the fluid material being adapted to experience a pressure related to the weight of the object; pressure sensing means coupled and adapted to provide a signal indicative of said pressure; processing means adapted to receive said signal and provide an output related to the weight of said object; and display means for displaying the output. 2. The weight measuring device according to claim 1, wherein the measuring platform is a container filled with liquid. 3. The weight measuring device according to claim 1 or 2, wherein the pressure sensing means includes a pressure transducer. 4. The weight measuring device according to any one of claims 1 to 3, wherein the processing means includes a microprocessor. 5. The weight measuring device according to any one of claims 1 to 4, wherein the display means includes one or more digital display elements. 6. The weight measuring device according to any one of claims 1 to 5, further comprising a keyboard connectable to the processing means for controlling the operation of the device. 7. The keyboard is in standard mode, idle mode,
7. The weight measuring device according to claim 6, wherein one or more selectable operation modes can be selected, such as an addition mode, a comparison mode, and an accumulation mode.