US 4,364,442 AGranted

Digital scale

AssigneeL. & D. Sales Corporation

InventorJon M. Flickinger

Life of this patent

Estimating the term…

Abstract

A digital scale and circuitry therefor, includes a power supply electrically connected to a control logic circuitry and a bridge supply circuitry. The bridge supply circuitry is electrically attached to a strain gage bridge which is electrically connected to an amplifier circuitry. The amplifier circuitry electronically engages an AD converter which electrically connects to a logic circuit and the control logic circuitry. The logic circuit and the control logic circuitry are electrically interconnected and each electrically attach to a display driver circuitry for displaying digits on a digital screen.

Claims6

Dependent claims

A digital scale having a digital screen for displaying digits comprising,

a. a power supply means;
b. a bridge supply means;
c. a control logic means, said bridge supply means and control logic means being electrically engaged by said power supply means;
d. strain gauge bridge means including at least two strain gauges and electrically engaged by said bridge supply means in two places;
e. an amplifier means electrically engaging said strain gauge bridge means in two places;
f. an A-D converter means electrically connected to said amplifier means and to said control logic means;
g. a logic means electrically attached to said A-D converter means and to said control logic means;
and
h. a display driver means electrically connected to said logic means to said control logic means, and to said digital screen for displaying digits thereon;
i. a base;
a support means attached to said base;
at least one beam attached to said support means, said beam having one of said two strain gauges attached on the top thereof and the other strain gauge connected on the bottom thereof;
at least one U-shaped mounting member mounted on each beam;
and a weigh plate means resting upon said U-shaped mounting member;
said bridge supply means includes a bridge supply circuitry including a first conductor, a first operational amplifier means connected to said first conductor, a first transistor means electrically connected to said first operational amplifier means, a second conductor electrically connected to said operational amplifier means, and to the collector electrode of said transistor means, a third conductor connected to the emitter electrode of said first transistor means and to a second operational amplifier means;
said third conductor having a first resistor means;
a first capacitor means and a second circuit common connection means, in series and in order stated, electrically connecting from said first conductor;
a second resistor means, a third resistor means, and a first circuit common connection means, in series and in order stated, electrically connecting from said third conductor between said first transistor means and said first resistor means, said third resistor being variable and electrically connecting to said first operational amplifier means;
a third circuit common connection means electrically connected to said second operational amplifier means, a fourth conductor connecting from said third conductor, at a point between said second operational amplifier means and said first resistor means, to said second operational means, said fourth conductor including a fourth resistor means, and a second transistor means, in series and in order stated, from said third conductor;
and a fifth conductor connecting from said second transistor means to said second operational amplifier means;
said driver display means includes each of said display digits of said digital screen having a circuitry comprising a third transistor means having an emitter electrode electrically connected to a 7-segment decoder/driver means, a fifth resistor means electrically connected to said third transistor means, said display digits being electrically connected in series with each other and further in series with said 7-segment decoder/driver means;
said logic means comprises a six decade counter means electrically connected in series with said 7-segment decoder/driver means, said fifth resistor means being electrically connected in series to said decade counter means;
said control logic means comprises at least one monostable multivibrator means directly electrically connected to said six decade counter means, a first flip-flop means directly electrically attached to said 7-segment decoder/driver means, a second flip-flop means directly electrically engaging said flip-flop means, and at least one R-5 flip-flop nor gate means electrically engaging said at least one monostable multivibrator means.

20 more elements

Dependencies are inferred from the claim text.

patentgrep

Loading patent…

Abstract

A digital scale having a digital screen for displaying digits comprising,

a. a power supply means;
b. a bridge supply means;
c. a control logic means, said bridge supply means and control logic means being electrically engaged by said power supply means;
d. strain gauge bridge means including at least two strain gauges and electrically engaged by said bridge supply means in two places;
e. an amplifier means electrically engaging said strain gauge bridge means in two places;
f. an A-D converter means electrically connected to said amplifier means and to said control logic means;
g. a logic means electrically attached to said A-D converter means and to said control logic means;
and
h. a display driver means electrically connected to said logic means to said control logic means, and to said digital screen for displaying digits thereon;
i. a base;
a support means attached to said base;
at least one beam attached to said support means, said beam having one of said two strain gauges attached on the top thereof and the other strain gauge connected on the bottom thereof;
at least one U-shaped mounting member mounted on each beam;
and a weigh plate means resting upon said U-shaped mounting member;
said bridge supply means includes a bridge supply circuitry including a first conductor, a first operational amplifier means connected to said first conductor, a first transistor means electrically connected to said first operational amplifier means, a second conductor electrically connected to said operational amplifier means, and to the collector electrode of said transistor means, a third conductor connected to the emitter electrode of said first transistor means and to a second operational amplifier means;
said third conductor having a first resistor means;
a first capacitor means and a second circuit common connection means, in series and in order stated, electrically connecting from said first conductor;
a second resistor means, a third resistor means, and a first circuit common connection means, in series and in order stated, electrically connecting from said third conductor between said first transistor means and said first resistor means, said third resistor being variable and electrically connecting to said first operational amplifier means;
a third circuit common connection means electrically connected to said second operational amplifier means, a fourth conductor connecting from said third conductor, at a point between said second operational amplifier means and said first resistor means, to said second operational means, said fourth conductor including a fourth resistor means, and a second transistor means, in series and in order stated, from said third conductor;
and a fifth conductor connecting from said second transistor means to said second operational amplifier means;
said driver display means includes each of said display digits of said digital screen having a circuitry comprising a third transistor means having an emitter electrode electrically connected to a 7-segment decoder/driver means, a fifth resistor means electrically connected to said third transistor means, said display digits being electrically connected in series with each other and further in series with said 7-segment decoder/driver means;
said logic means comprises a six decade counter means electrically connected in series with said 7-segment decoder/driver means, said fifth resistor means being electrically connected in series to said decade counter means;
said control logic means comprises at least one monostable multivibrator means directly electrically connected to said six decade counter means, a first flip-flop means directly electrically attached to said 7-segment decoder/driver means, a second flip-flop means directly electrically engaging said flip-flop means, and at least one R-5 flip-flop nor gate means electrically engaging said at least one monostable multivibrator means.

20 more elements