US4405025A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic weighing apparatus of induction type
Assignee: Tanita Corp
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Filing: 1981-09-15
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Granted: 1983-09-20
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Expires: 2001-09-15
Abstract
Abstract An electronic weighing apparatus of induction type comprises a weighing member adapted to be moved according to the weight of a load to be measured, a variable inductance element consisting of a coil and a magnetic core which is movable relatively to the coil through the coil, a connecting member for connecting the weighing member with one of the coil and the magnetic core of the inductance element so that the one can be moved with respect to the other according to the movement of the weighing member and thus the inductance of the inductance element can be changed proportionally to the movement of the weighing member, a sensor oscillator including the variable inductance element as one of its oscillating parameters for generating a series of pulses having a characteristic representative of the inductance of the variable inductance element, a converting circuit for converting the characteristic of the output pulses from the sensor oscillator into a weight signal indicative of the weight of the load, and a display for receiving the weight signal from the converting circuit and providing an indication of the weight of the load.
Inventors
- 👤 Shuichi Yanagita
- 👤 Tsutomu Miyoshi
- 👤 Masashi Miyane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:11
CPC Classifications
G; G01; G01G; G01G23/00; G01G23/18; G01G23/36; G01G23/37; G01G7/00; G01G7/02; G01G7/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
258 words
An electronic weighing apparatus of the induction type comprises a weighing member adapted to be moved according to the weight of a load to be measured, a variable inductance element consisting of a coil and a magnetic core which is movable relative to said coil and through said coil, means for connecting said weighing member with one of said coil and said magnetic core of said inductance element so that said one can be moved with respect to the other according to the movement of said weighing member and thus the inductance of said inductance element can be changed proportionally to the movement of said weighing member, a sensor oscillator for generating at an output a series of pulses having a period representative of the inductance of said variable inductance element, means connected to receive said pulses and arranged for converting said period of said output pulses from said sensor oscillator into a weight signal indicative of the weight of said load, a display for receiving said weight signal from said converting means and providing an indication of the weight of said load, said sensor oscillator comprising a comparator having an inverting input terminal, a non-inverting input terminal and an output terminal and an integrator having an inverting input terminal, a non-inverting input terminal and an output terminal, said coil of said variable inductance element being connected between said output terminal of said comparator and said non-inverting input terminal of said intergrator, and said output terminal of said comparator being connected to the output of said sensor oscillator.
Claim 2
Dependent Claim
258 words
An electronic weighing apparatus of the induction type comprises a weighing member adapted to be moved according to the weight of a load to be measured, a variable inductance element consisting of a coil and a magnetic core which is movable relative to said coil and through said coil, means for connecting said weighing member with one of said coil and said magnetic core of said inductance element so that said one can be moved with respect to the other according to the movement of said weighing member and thus the inductance of said inductance element can be changed proportionally to the movement of said weighing member, a sensor oscillator for generating at an output a series of pulses having a period representative of the inductance of said variable inductance element, means connected to receive said pulses and arranged for converting said period of said output pulses from said sensor oscillator into a weight signal indicative of the weight of said load, a display for receiving said weight signal from said converting means and providing an indication of the weight of said load, said sensor oscillator comprising a comparator having an inverting input terminal, a non-inverting input terminal and an output terminal and an integrator having an inverting input terminal, a non-inverting input terminal and an output terminal, said coil of said variable inductance element being connected between said output terminal of said comparator and said non-inverting input terminal of said intergrator, and said output terminal of said comparator being connected to the output of said sensor oscillator.
Claim 3
Dependent Claim
86 words
An electronic weighing apparatus as defined in claim 1 wherein said means for converting comprises a first counter for counting a predetermined number of output pulses from said sensor oscillator and outputting a pulse having a pulse width proportional to the time required to count the predetermined number of the output pulses, a clock pulse generator and a second counter for counting the clock pulses from said clock pulse generator for a time period equal to the pulse width of the pulse from said first counter.
Claim 4
Dependent Claim
46 words
An electronic weighing apparatus as defined in claim 1 wherein said coil of said variable inductance element consists of at least three windings arranged along the axis of said coil, the outer ones of said windings having a larger number of turns than the inner ones.
Claim 5
Dependent Claim
79 words
An electronic weighing apparatus as defined in claim 1 further including a first resistor connected between said non-inverting input terminal of said integrator and said output terminal of said integrator, a second resistor connected between said output terminal of said integrator and said inverting input terminal of said comparator, a third resistor connected between said inverting input of said comparator and said non-inverting input terminal of said comparator and said non-inverting input terminal of integrator being connected to ground.
Claim 6
Dependent Claim
38 words
An electronic weighing apparatus as defined in claim 1 including means connected across said coil for linearizing the relation of said period of said output pulses of said sensor oscillator with the moved distance of said magnetic core.
Claim 7
Dependent Claim
20 words
An electronic weighing apparatus as defined in claim 4 wherein said means connected across said coil is a compensating resistor.
Claim 8
Dependent Claim
47 words
An electronic weighing apparatus as defined in claim 5 further including means connected between the output terminal of the integrator and the non-inverting input terminal of the integrator for compensating for a change in oscillating pulses from the sensor oscillator due to a change in ambient temperature.
Claim 9
Dependent Claim
33 words
An electronic weighing apparatus as defined in claim 7 wherein said means connected between the output terminal of the integrator and the non-inverting input terminal of the integrator is a temperature sensitive element.
Claim 10
Dependent Claim
17 words
An electronic weighing apparatus as defined in claim 8 wherein said element has a positive temperature coefficient.
Claim 11
Dependent Claim
39 words
An electronic weighing apparatus as defined in claim 1 further including means connected across said coil for linearizing the relation of said period of said output pulses of said sensor oscillator with the moved distance of said magnetic core.
Claim 12
Dependent Claim
20 words
An electronic weighing apparatus as defined in claim 10 wherein said means connected across said coil is a compensating resistor.
Claim 13
Dependent Claim
47 words
An electronic weighing apparatus as defined in claim 10 further including means connected between the output terminal of the integrator and the non-inverting input terminal of the integrator for compensating for a change in oscillating pulses from the sensor oscillator due to a change in ambient temperature.
Claim 14
Dependent Claim
33 words
An electronic weighing apparatus as defined in claim 12 wherein said means connected between the output terminal of the integrator and the non-inverting input terminal of the integrator is a temperature sensitive element.
Claim 15
Dependent Claim
17 words
An electronic weighing apparatus as defined in claim 13 wherein said element has a positive temperature coefficient.
References Cited (Backward Citations)
US4173263A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-19 | 1987-03-21 | 1987-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-19 | 1991-03-21 | 1991-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-19 | 1995-03-21 | 1995-09-20 | $7700.00 | Window Closed / Lapsed |