US3786883A — Electromagnetically-compensated balance having se…

Claim 1

Independent Claim 322 words

An electromagnetically-compensated balance including, in combination, a stationary housing (2); load (12) and reference (13) assemblies connected for independent movement relative to said housing, said assemblies normally having no-load neutral positions relative to said housing; load (10) and reference (11) compensation coils connected with said load and reference assemblies, respectively; means (3) establishing a magnetic field common to said load and reference compensation coils; and means for energizing said load and reference compensation coils when the assemblies associated therewith are displaced from their neutral positions in sUch a manner relative to said magnetic field as to return said assemblies to their neutral positions, respectively, said energizing means comprising a. a direct-current voltage source (S) having a first terminal connected with one end of the load compensation coil; b. a reference current regulator (21) connected in series with the reference compensation coil to define a series branch one end of which is connected with the other terminal of said voltage source; c. switch means (23) alternately operable between first and second conditions for connecting and disconnecting the other end of said series branch with the other end of said load compensation coil, respectively; d. reference position detector means (19, 19'', 20) for generating a reference control voltage that corresponds with the displacement of the reference assembly from its neutral position, said reference position detector means being connected with said reference current regulator means to regulate the current in said series branch as a function of the magnitude of the reference control voltage; e. load position detector means (18, 18'', 25) for generating a load control voltage that corresponds with the displacement of the load assembly from its neutral position; and f. means (27) connected with said load position detector means for controlling the operation of said switch means to cause the periods of time that said switch means is in the first condition to correspond with the magnitude of the load control voltage.

Claim 2

Dependent Claim 322 words

An electromagnetically-compensated balance including, in combination, a stationary housing (2); load (12) and reference (13) assemblies connected for independent movement relative to said housing, said assemblies normally having no-load neutral positions relative to said housing; load (10) and reference (11) compensation coils connected with said load and reference assemblies, respectively; means (3) establishing a magnetic field common to said load and reference compensation coils; and means for energizing said load and reference compensation coils when the assemblies associated therewith are displaced from their neutral positions in sUch a manner relative to said magnetic field as to return said assemblies to their neutral positions, respectively, said energizing means comprising a. a direct-current voltage source (S) having a first terminal connected with one end of the load compensation coil; b. a reference current regulator (21) connected in series with the reference compensation coil to define a series branch one end of which is connected with the other terminal of said voltage source; c. switch means (23) alternately operable between first and second conditions for connecting and disconnecting the other end of said series branch with the other end of said load compensation coil, respectively; d. reference position detector means (19, 19'', 20) for generating a reference control voltage that corresponds with the displacement of the reference assembly from its neutral position, said reference position detector means being connected with said reference current regulator means to regulate the current in said series branch as a function of the magnitude of the reference control voltage; e. load position detector means (18, 18'', 25) for generating a load control voltage that corresponds with the displacement of the load assembly from its neutral position; and f. means (27) connected with said load position detector means for controlling the operation of said switch means to cause the periods of time that said switch means is in the first condition to correspond with the magnitude of the load control voltage.

Claim 3

Dependent Claim 23 words

Apparatus as defined in claim 1, and further including buffer means (22) connected in series between said series branch and said switch means.

Claim 4

Dependent Claim 27 words

Apparatus as defined in claim 2, wherein said buffer means has a 1:1 amplification ratio and forms a galvanic coupling between the load and reference compensation coils.

Claim 5

Dependent Claim 17 words

Apparatus as defined in claim 3, wherein said buffer means includes at least one field effect transistor.

Claim 6

Dependent Claim 28 words

Apparatus as defined in claim 1, and further including means for stabilizing the switching characteristic of said switching means when said switching means is in the second condition.

Claim 7

Dependent Claim 49 words

Apparatus as defined in claim 5, wherein said stabilizing means comprises a dummy load (24) connected at one end with said first terminal of said voltage source, said switch means being operable in said second condition to connect the other end of said dummy load with said series branch.

Claim 8

Dependent Claim 39 words

Apparatus as defined in claim 5, wherein said stabilizing means comprises catching diode means (d) connected at one end between said series branch and said switch means, the other end of said catching diode means being connected with ground.

Claim 9

Dependent Claim 60 words

Apparatus as defined in claim 1, wherein said means for controlling the operation of said switch means comprises sawtooth waveform generator means including an oscillator (28), and pulse length modulator means (27) for comparing said sawtooth waveform and said load control voltages to produce switch control voltage pulses the lengths of which are a function of said load control voltage.

Claim 10

Dependent Claim 57 words

Apparatus as defined in claim 8, and further including counter means (33) for counting pulses produced by said oscillator means during the time periods of said switch means is in said first condition, and indicator means (36) for indicating as a function of the total count of said counter means the load applied to said load assembly.

Claim 11

Dependent Claim 126 words

Apparatus as defined in claim 9, wherein said counter means further includes a forward-reverse counter (33), and taring means for initially subtracting from said counter means counting pulses corresponding with the tare value of the balance, said taring means including tare store means (38) for storing the tare count, forward-reverse logic means (39) connected with said counter means, zero detector means (41) connected between said tare store means and said forward-reverse logic means for reversing the direction of said counter means when the count stored in said tare storage means equals zero, and counter control means (32) for introducing the initial tare count into said tare storage means and for controlling the operation of said forward-reverse logic means, said counter means, and said tare storage means.

Claim 12

Dependent Claim 27 words

Apparatus as defined in claim 1, and further including resilient means (14,14'' and 15,15'') for supporting said load and reference assemblies for movement relative to said housing.

Claim 13

Dependent Claim 59 words

Apparatus as defined in claim 11, wherein said housing contains a chamber and wherein said means establishing a magnetic field comprises a permanent magnet (3) mounted within said housing chamber to define an annular air gap (9), said load and reference assemblies and said load and reference coils comprising concentrically arranged annular members contained in said annular air gap.

Claim 14

Dependent Claim 50 words

Apparatus as defined in claim 12, wherein each of said load and reference detector means comprises a pair of annular capacitors connected with said housing on opposite sides of said load and reference coils, said detector means being colinearly arranged relative to the axis of said load and reference assemblies.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-01-21	1977-07-23	1978-01-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-01-21	1981-07-23	1982-01-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-01-21	1985-07-23	1986-01-22	$7700.00	Window Closed / Lapsed

Electromagnetically-compensated balance having series connected coils

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag