EP0430695A2
Expired / Lapsed
EP
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Weighing apparatus
Assignee: Ishida Co Ltd
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Filing: 1990-11-30
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Granted: —
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Expires: 2010-11-30
Abstract
Abstract A weighing apparatus has a scale cell (1) and a dummy cell (5), both similarly structured and cantilevered. A load to be measured is applied to the free end of the scale cell and a standard weight (6) is attached to the free end of the dummy cell. Analogue electrical signals from these cells are converted to digital data. The effect of the standard weight (6) is removed from the digital data from the dummy cell (5) to obtain the effect of external vibrations which effect is multiplied by a suitable coefficient dependent on the applied load and subtracted from the digital data from the scale cell (1). <IMAGE>
Inventors
- 👤 Yoshihiro Nakamura
- 👤 Kazufumi Naito
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 08:03
CPC Classifications
G; G01; G01G; G01G23/00; G01G23/06; G01G23/10; G01G3/00; G01G3/12; G01G3/14; G01G3/1414; G01G3/142; G01G3/147
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
147 words
Weighing apparatus comprising a weight-measuring load cell (1), one end of which is secured to a base (2) and the other end of which supports a load-carrying table; a dummy load cell (5), one end of which is secured to the base (2), a standard weight (6) being attached to the other end of the dummy cell; analogue-to-digital converter means (12,13) for converting analog electrical signals from said load cells to digital data; filter means (14,15) for filtering the digital data, multiplier means (20) for multiplying filtered digital data from the dummy load cell (5) by a coefficient which is dependent on the weight of an object being weighed; and subtractor means (21) for determining the difference between filtered, digital data from the weight-measuring load cell (1) and data from the multiplier means (20), so as to compensate for the effect of vibrations of the weighing apparatus.
Claim 2
Dependent Claim
87 words
A weighing apparatus according to claim 1, wherein the analogue-to digital converter means comprise first analogue-to-digital converter means (12) for converting analogue electrical signals from the weight-measuring load cell to digital data and second analogue-to-digital converter (13) means for converting analogue electrical signals from the dummy load cell (5) to digital data; and wherein the filter means comprise first filter means (14) for filtering digital data from said first analogue-to-digital converter means and second filter means (15) for filtering digital data from the second analogue-todigital converter means.
Claim 3
Dependent Claim
57 words
A weighing apparatus according to claim 1, further comprising signal multiplexing means (23) for alternately outputing signals from the weight-measuring load cell (1) and the dummy load cell (5) at a multiplexing frequency which is shorter than external vibration frequencies; and wherein the filtering means (15) filter digital data from the analogue-to-digital means at the multiplexing frequency.
Claim 4
Dependent Claim
39 words
A weighing apparatus according to claim 3, further comprising a common preamplifier means (31) for receiving outputs from the signal multiplexing means, and wherein the analogue-to-digital converter means (32) convert outputs from the preamplifier means (31) to digital data.
Claim 5
Dependent Claim
15 words
Weighing apparatus according to any preceding claim wherein the coefficient is proportional to the weight.
References Cited (Backward Citations)
No citation records indexed.
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