Patent US3585457A successfully refreshed from Google Patents.
US3585457A
Expired / Lapsed
US
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Material level sensing device and indicating system
Assignee: Fuller Co
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Filing: 1969-05-01
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Granted: 1971-06-15
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Expires: 1989-05-01
Abstract
Abstract This invention relates to the art of level sensing devices and more particularly to a sensing device and associated circuit for providing an indication when the level of material in a chamber has reached a predetermined position. The sensing device comprises a vibratory reed of length substantially equal to three-quarters of a wavelength and resiliently mounted at two points substantially one-half wavelength apart and projecting from one of said resilient mounts by a distance of substantially one-quarter of a wavelength, the reed having associated drive and pickup coils which are in an oscillatory circuit including an amplifier and a limiter, the latter determining the maximum drive potential applied to the drive coils, the circuit including a control device adapted to be actuated when the signal fed thereto from the amplifier falls a predetermined amount below a reference level of value proportional to the maximum output from the limiter.
Inventors
- 👤 Carl J Zaander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:28
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/296; G01F23/2966; G01F23/2967
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
150 words
A level sensing system comprising a sensing device having a body portion, an elongated vibratory reed of magnetic material mounted in said body portion and protruding outwardly from one end thereof, a drive coil unit and a pickup coil unit mounted in said body portion, means to amplify the signal from said pickup unit to provide an alternating current voltage, means to limit the maximum amplitude of said alternating current voltage to a predetermined amount, means to feed the output of said limiting means to said drive unit, means to rectify the amplified output from said amplifier to provide a direct current potential, a time delay unit having an input fed by said direct current potential and a control device connected to the output of said time delay unit and adapted to be actuated when the value of the output of said time delay unit falls below a predetermined amount.
Claim 2
Dependent Claim
150 words
A level sensing system comprising a sensing device having a body portion, an elongated vibratory reed of magnetic material mounted in said body portion and protruding outwardly from one end thereof, a drive coil unit and a pickup coil unit mounted in said body portion, means to amplify the signal from said pickup unit to provide an alternating current voltage, means to limit the maximum amplitude of said alternating current voltage to a predetermined amount, means to feed the output of said limiting means to said drive unit, means to rectify the amplified output from said amplifier to provide a direct current potential, a time delay unit having an input fed by said direct current potential and a control device connected to the output of said time delay unit and adapted to be actuated when the value of the output of said time delay unit falls below a predetermined amount.
Claim 3
Dependent Claim
55 words
The combination set forth in claim 1 in which said control device is a relay having a coil, said time delay unit comprises a resistor and a capacitor, the coil of said relay being connected across said capacitor, whereby said relay will be actuated when the voltage across said capacitor falls below a predetermined amount.
Claim 4
Dependent Claim
100 words
The combination set forth in claim 1 in which the reed has a length substantially equal to three-quarters of a wavelength and is resiliently mounted in said body portion at two longitudinally spaced positions, one of said positions being adjacent one end of said body portion, the distance between said two positions being substantially equal to one-half a wavelength with the portion of the reed protruding from said one end of said body portion being of Length substantially equal to one-quarter of a wavelength, the drive and pickup units being positioned adjacent the point of maximum amplitude of the reed.
Claim 5
Dependent Claim
30 words
The combination set forth in claim 3 in which the drive and pickup units are positioned on opposed sides of said reed, symmetrically located between the two resilient mounts thereof.
Claim 6
Dependent Claim
28 words
The combination set forth in claim 4 in which each of the drive units comprises an electromagnetic device, said devices being longitudinally spaced, whereby electrical coupling is minimized.
Claim 7
Dependent Claim
94 words
The combination set forth in claim 1 in which the body portion of said sensing device is elongated, having two opposed end portions and an intermediate portion, said body portion having a longitudinal passageway therethrough through which said reed extends, said reed being resiliently mounted at two longitudinally spaced positions located respectively in the ends of said body portion, the distance between said resilient mounts being substantially equal to two-thirds of the length of the reed and the protruding portion of said reed being substantially equal to one-third of the length of the reed.
Claim 8
Dependent Claim
99 words
The combination set forth in claim 6 in which each of said end portions has a cylindrical bore therethrough defining a part of said longitudinal passageway, one of said bores having a seat in its outer end, a resilient disc retained on said seat, the protruding portion of said reed extending through said resilient disc, the latter defining one of the resilient mounts, a clamp member of resilient material mounted in the outer end of said other bore, the free end of said reed being gripped by said resilient clamp to define the other resilient mount of said reed.
Claim 9
Dependent Claim
123 words
A level sensing system comprising a vibratory reed, a drive coil and a pickup coil associated with said reed, means to amplify the signal from said pickup coil to provide an alternating current output, a limiter fed by said alternating current output to provide a drive signal of maximum predetermined value, means to feed said drive signal to said drive coil, means to rectify the amplified signal from said amplifier to provide a direct current signal and a current controlled actuating device fed by said rectifier, said current controlled device being designed to be actuated when the direct current signal applied thereto falls a predetermined amount below a reference level, said reference level being determined by the maximum output signal from said limiter.
Claim 10
Dependent Claim
123 words
A level sensing system comprising a vibratory reed, a drive coil and a pickup coil associated with said reed, means to amplify the signal from said pickup coil to provide an alternating current output, a limiter fed by said alternating current output to provide a drive signal of maximum predetermined value, means to feed said drive signal to said drive coil, means to rectify the amplified signal from said amplifier to provide a direct current signal and a current controlled actuating device fed by said rectifier, said current controlled device being designed to be actuated when the direct current signal applied thereto falls a predetermined amount below a reference level, said reference level being determined by the maximum output signal from said limiter.
Claim 11
Dependent Claim
45 words
The combination set forth in claim 8 in which means are provided to maintain the signal on said control device above the actuating point for a predetermined period of time after the direct current signal form the rectifier means has fallen below such predetermined amount.
Claim 12
Dependent Claim
66 words
The combination set forth in claim 9 in which said signal maintaining means comprises a resistor-capacitor network, said capacitor being chargeable to a maximum amount determined by the predetermined maximum output signal from said limiter, said resistor-capacitor network having a time constant equal to the period for which the signal applied to the actuating device from said network is to be maintained above the actuating point.
Claim 13
Dependent Claim
142 words
A sensing device comprising an elongated body portion having two opposed end portions and an intermediate portion, said body portion having a passageway extending longitudinally therethrough, an elongated vibratory reed of magnetic material extending longitudinally through said passageway and protruding beyond one of said end portions, means in each of said end portions mounting said reed, and an electromagnetic drive unit and pickup unit positioned in said intermediate portion on opposed sides respectively of said reed, said reed having a length substantially equal to three-quarters of a wavelength and the distance between the mounts for said reed in said end portions is substantially equal to one-half of a wavelength and the length portions is substantially equal to one-quarter of a wavelength, said drive coil and said pickup coil being symmetrically located with respect to the midportion of said reed between said mounts.
Claim 14
Dependent Claim
142 words
A sensing device comprising an elongated body portion having two opposed end portions and an intermediate portion, said body portion having a passageway extending longitudinally therethrough, an elongated vibratory reed of magnetic material extending longitudinally through said passageway and protruding beyond one of said end portions, means in each of said end portions mounting said reed, and an electromagnetic drive unit and pickup unit positioned in said intermediate portion on opposed sides respectively of said reed, said reed having a length substantially equal to three-quarters of a wavelength and the distance between the mounts for said reed in said end portions is substantially equal to one-half of a wavelength and the length portions is substantially equal to one-quarter of a wavelength, said drive coil and said pickup coil being symmetrically located with respect to the midportion of said reed between said mounts.
Claim 15
Dependent Claim
24 words
The combination set forth in claim 11 in which said pickup coil and said drive coil are longitudinally displaced to minimize electrical coupling therebetween.
Claim 16
Dependent Claim
51 words
The combination set forth in claim 11 in which said end portion from which said reed protrudes is of larger diameter than said intermediate portion and said other end portion and an elongated casing encompassing said body portion is removably secured to said larger diameter end portion in sealing engagement therewith.
Claim 17
Dependent Claim
50 words
The combination set forth in claim 13 in which said larger diameter end portion is externally threaded and said casing comprises a tubular member internally threaded at one end to coact with threaded end portion, said tubular member extending rearwardly from said threaded end portion to which it is secured.
Claim 18
Dependent Claim
86 words
The combination set forth in claim 11 in which each of said end portions has a cylindrical bore therethrough, which bores define portions of said longitudinal passageway, a resilient washer is seated on the outer end of the bore in the end portion from which the reed protrudes, said reed extending through said resilient washer which defines a resilient mount, a resilient strip being positioned in the outer end of said other bore and engaging the end of said reed to define a second resilient mount.
Claim 19
Dependent Claim
27 words
The combination set forth in claim 15 in which said resilient washer is molded integrally with said reed hermetically to seal one end of said longitudinal passageway.
Claim 20
Dependent Claim
79 words
The combination set forth in claim 15 in which an end plate is provided for the outer end of said other bore, said strip of resilient material being mounted on the inner surface of said end plate, the free end of said reed being encompassed by said strip, means to secure said end plate to the end wall of said end portion and means to compress said strip resiliently to clamp the free end of the reed in position.
Claim 21
Dependent Claim
76 words
The combination set forth in claim 17 in which a substantially U-shaped slip of flexible material is positioned against the inner surface of said end plate, said strip of resilient material being positioned between the legs of said clip, said strip having longitudinal slot in which the free end of the reed is received and means to move the opposed legs of said clip together to clamp said strip against the free end of said reed.
Claim 22
Dependent Claim
133 words
The combination set forth in claim 17 in which said end plate has a recess in its inner surface, a substantially U-shaped clip of flexible material is positioned in said recess with the legs of said clip extending outwardly therefrom, said strip of resilient material is positioned between the legs of said clip, said strip having a slit extending inwardly from its outer surface, the free end of said reed being positioned in said slit, said plate having bosses extending outwardly from the inner surface thereof on opposed sides of said clip, said bosses having longitudinally threaded bores therethrough and a setscrew in each of said threaded bores adapted to react against the legs of said clip when tightened to compress said resilient strip, thereby resiliently clamping the free end of said reed.
Claim 23
Dependent Claim
172 words
The combination set forth in claim 11 in which each of said end portions is substantially cylindrical and said intermediate portion comprises a pair of spaced parallel strips extending between said end portions, said end portions having longitudinally aligned bores therethrough leading into a recess defined between said strips, said reed extending longitudinally through said aligned bores and said recess, and protruding beyond one of said end portions, said reed being mounted in said end portions with said mounts being spaced by substantially two-thirds the length of the reed with the protruding portion of said reed being substantially equal to one-third of the length of the reed, a pair of coil assemblies are provided, one comprising a drive unit and the Other a pickup unit, each of said coil assemblies having a baseplate secured to the inner surface of an associated strip and having core portions extending inwardly from said base portion, each of said core portions having an encompassing coil, said reed extending between said drive unit and said pickup unit.
Claim 24
Dependent Claim
95 words
The combination set forth in claim 20 in which a transverse wall is positioned adjacent the outer end of the bore in said end portion from which the reed protrudes, said wall having an elongated slot therethrough through which said reed protrudes, the outer end of said bore having an enlarged diameter recess defining an annular shoulder, a gasket of resilient material seated on said shoulder, said reed extending through said gasket and being bonded thereto, said gasket defining a resilient mount for said reed and means securely to clamp said gasket on said seat.
Claim 25
Dependent Claim
102 words
The combination set forth in claim 11 in which a guard member extends longitudinally outward from the end of said body portion from which the reed protrudes, said guard member being U-shaped and having a pair of spaced parallel legs extending outward from the rear end thereof and a crosspiece at the outer ends of said legs formed integral therewith, means securely to retain the rear end of said guard to said end of said body portion, said reed extending longitudinally between the legs of said guard with the free end of said reed being spaced from the crosspiece of said guard.
Claim 26
Dependent Claim
38 words
The combination set forth in claim 22 in which each of the legs of said guard and said crosspiece is substantially triangular in cross section in the form of an isosceles triangle having the apex thereof directed inwardly.
Claim 27
Dependent Claim
73 words
The combination set forth in claim 22 in which the rear end of said guard defines an end wall longitudinally spaced from and parallel to the crosspiece of said guard, said end wall having a central bore therethrough and means to secure the end wall of said guard to the end wall of said end portion, with the central opening of said guard longitudinally aligned with the longitudinal passageway of said body portion.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |