US5182979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linear position sensor with equalizing means
Assignee: Mid-America Commercialization Corp
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Filing: 1992-03-02
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Granted: 1993-02-02
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Expires: 2012-03-02
Abstract
Abstract An apparatus is adapted to detect the linear extension, velocity and acceleration of a hydraulic cylinder. The hydraulic cylinder defines a variable length coaxial resonant cavity. Under the control of a controller, an RF transmitting section and an RF receiving section are used to determine the resonant frequency of the cavity. The receiving section includes an equalizer circuit for compensating for the insertion losses of the hydraulic cylinder. The linear extension of the cylinder is determined as a function of the resonant frequency.
Inventors
- 👤 Denny E. Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:16
CPC Classifications
F; F15; F15B; F15B15/00; F15B15/20; F15B15/28; F15B15/2815; F15B15/2869; F02; F02B; F02B77/00; F02B77/08; F02B77/087; B; B29; B29C; B29C49/00; B29C49/42; B29C49/78; B29C2049/7879; Y; Y10; Y10S; Y10S91/00; Y10S91/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
138 words
An apparatus for detecting a linear position of a piston and a piston rod being movable within a housing of a hydraulic cylinder, comprising: means for producing an electromagnetic signal and delivering said electromagnetic signal into said hydraulic cylinder, said electromagnetic signal having a frequency varying between predetermined minimum and maximum values; means for determining a resonant frequency of the hydraulic cylinder, said resonant frequency detecting means including means for sensing an electromagnetic wave signal within said hydraulic cylinder and equalizing said received electromagnetic signal, said equalization accounting for the losses of said hydraulic cylinder, comparing said equalized electromagnetic wave signal with a predetermined constant and responsively producing a frequency signal, said frequency signal being indicative of said resonant frequency; and means for receiving said frequency signal and responsively determining the position of said piston and piston rod.
Claim 2
Independent Claim
138 words
An apparatus for detecting a linear position of a piston and a piston rod being movable within a housing of a hydraulic cylinder, comprising: means for producing an electromagnetic signal and delivering said electromagnetic signal into said hydraulic cylinder, said electromagnetic signal having a frequency varying between predetermined minimum and maximum values; means for determining a resonant frequency of the hydraulic cylinder, said resonant frequency detecting means including means for sensing an electromagnetic wave signal within said hydraulic cylinder and equalizing said received electromagnetic signal, said equalization accounting for the losses of said hydraulic cylinder, comparing said equalized electromagnetic wave signal with a predetermined constant and responsively producing a frequency signal, said frequency signal being indicative of said resonant frequency; and means for receiving said frequency signal and responsively determining the position of said piston and piston rod.
Claim 3
Dependent Claim
35 words
An apparatus, as set forth in claim 1, wherein said piston, piston rod, and housing define a variable length coaxial cavity and said electromagnetic signal is a transverse electromagnetic wave delivered into said coaxial cavity.
Claim 4
Dependent Claim
43 words
An apparatus, as set forth in claim 1, wherein said position determining means includes means for determining a resonant frequency of said coaxial cavity and wherein the position of said piston and piston rod is determined as a function of said resonant frequency.
Claim 5
Independent Claim
29 words
An apparatus, as set forth in claim i, wherein said comparing means includes means for detecting the amplitude of said electromagnetic wave signal and responsively producing a detected signal.
Claim 6
Dependent Claim
39 words
An apparatus, as set forth in claim 1, wherein an impedance of said equalizing means is substantially equal to the inverse of the impedance of said hydraulic cylinder over the frequency range defined by said minimum and maximum values.
Claim 7
Dependent Claim
30 words
An apparatus, as set forth in claim 1, wherein the gain of said equalizing means approaches a predetermined maximum as the frequency of said electromagnetic signal approaches said minimum value.
Claim 8
Dependent Claim
30 words
An apparatus, as set forth in claim 1, wherein the gain of said equalizing means approaches a predetermined minimum as the frequency of said electromagnetic signal approaches said maximum value.
Claim 9
Dependent Claim
47 words
An apparatus, as set forth in claim 1, wherein said equalizing means includes a first voltage gain component, X c , and a second impedance voltage gain, X e , and wherein the overall voltage gain of said equalizing means is approximately X c /X e .
Claim 10
Dependent Claim
24 words
An apparatus, as set forth in claim 8, wherein said first voltage gain component includes a first resistor and a capacitor connected in series.
Claim 11
Dependent Claim
25 words
An apparatus, as set forth in claim 8, wherein said second voltage gain component includes a second resistor and a first inductor connected in parallel.
Claim 12
Dependent Claim
41 words
An apparatus, as set forth in claim 8, wherein said first voltage gain component includes a first resistor and a capacitor connected in series and said second voltage gain component includes a second resistor and a first inductor connected in parallel.
Claim 13
Dependent Claim
70 words
An apparatus, as set forth in claim 1, wherein said equalizing means includes: a transistor; a first resistor connected to the collector of said transistor; a capacitor connected between said first resistor and the base of said transistor, said first resistor and said capacitor being connected in series; a second resistor connected between the emitter of said transistor and ground; and an inductor connected in parallel with said second resistor.
Claim 14
Independent Claim
185 words
An apparatus for detecting a linear position of a piston and a piston rod being movable within a housing of a hydraulic cylinder, comprising: means for producing an electromagnetic signal and delivering said electromagnetic signal into said hydraulic cylinder, said electromagnetic signal having a frequency varying between predetermined minimum and maximum values; means for determining a resonant frequency of the hydraulic cylinder, said resonant frequency detecting means including means for sensing an electromagnetic wave signal within said hydraulic cylinder and equalizing said received electromagnetic signal, said equalization accounting for the losses of said hydraulic cylinder, comparing said equalized electromagnetic wave signal with a predetermined constant and responsively producing a frequency signal; wherein said equalizing means includes: a transistor; a first voltage gain component, X c , connected between the collector and the base of said transistor; a second voltage gain component, X e , connected to the emitter of said transistor; wherein the overall voltage gain of said equalizing means is approximately X c /X e ; and means for receiving said frequency signal and responsively determining the position of said piston and piston rod.
Claim 15
Independent Claim
185 words
An apparatus for detecting a linear position of a piston and a piston rod being movable within a housing of a hydraulic cylinder, comprising: means for producing an electromagnetic signal and delivering said electromagnetic signal into said hydraulic cylinder, said electromagnetic signal having a frequency varying between predetermined minimum and maximum values; means for determining a resonant frequency of the hydraulic cylinder, said resonant frequency detecting means including means for sensing an electromagnetic wave signal within said hydraulic cylinder and equalizing said received electromagnetic signal, said equalization accounting for the losses of said hydraulic cylinder, comparing said equalized electromagnetic wave signal with a predetermined constant and responsively producing a frequency signal; wherein said equalizing means includes: a transistor; a first voltage gain component, X c , connected between the collector and the base of said transistor; a second voltage gain component, X e , connected to the emitter of said transistor; wherein the overall voltage gain of said equalizing means is approximately X c /X e ; and means for receiving said frequency signal and responsively determining the position of said piston and piston rod.
References Cited (Backward Citations)
US2520604A
Cited
US3589177A
Cited
US3726191A
Cited
US4365503A
Cited
US4588953A
Cited
US4901628A
Cited
US4689553A
Cited
US4737705A
Cited
US4757745A
Cited
US4987823A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-02-02 | 1996-08-03 | 1997-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-02 | 2000-08-03 | 2001-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-02 | 2004-08-03 | 2005-02-02 | $7700.00 | Window Closed / Lapsed |