US3581206A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronically controlled speedometer with maximum speed indicator
Assignee: Dr Ing HCF Porsche AG
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Filing: 1969-04-03
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Granted: 1971-05-25
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Expires: 1989-04-03
Abstract
Abstract An electronically controlled speedometer wherein the inductive impulses from the ignition coil whose frequency is proportional to the speed of the motor are shaped and integrated to form a control signal which is applied to a servoamplifier connected to a servomotor forming a servo loop, the servomotor driving the instantaneous speed indicator dial which in turn drags a maximum speed dial therewith in the direction of increasing speed indication, and a critical speed indicator responsive to a critical value of said control signal for interrupting the ignition circuit.
Inventors
- 👤 Siegfried Strohm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:21
CPC Classifications
G; G01; G01P; G01P1/00; G01P1/07; G01P1/08; G01P1/10; G01P1/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
192 words
An electronically controlled speedometer for indicating the speed of a motor having an electrical control system including an ignition coil, comprising: indicating means driveable to selective positions indicative of instantaneous speeds in a range of speeds including a rotatable speed indicating dial, a reversible servomotor connected through a reduction gear arrangement to said speed indicating dial for effecting a driving thereof to said selective positions in response to a control signal, a servoamplifier connected to said servomotor to form a servo loop therewith, pulse transmitter means connected to said ignition coil for generating a pulse train whose frequency is proportional to the speed of said motor, integrator means connected between said pulse transmitter means and said servoamplifier for generating said control signal having a magnitude proportional to the speed of said motor, and a rotatable drag dial for indicating maximum speed, a cam member driven from said reversible servomotor through said reduction gear arrangement, and a lifting device carrying a pin contacting said cam member so as to be driven thereby only in one direction, said lifting device being connected to said drag dial to drive said drag dial in rotation therewith.
Claim 2
Dependent Claim
192 words
An electronically controlled speedometer for indicating the speed of a motor having an electrical control system including an ignition coil, comprising: indicating means driveable to selective positions indicative of instantaneous speeds in a range of speeds including a rotatable speed indicating dial, a reversible servomotor connected through a reduction gear arrangement to said speed indicating dial for effecting a driving thereof to said selective positions in response to a control signal, a servoamplifier connected to said servomotor to form a servo loop therewith, pulse transmitter means connected to said ignition coil for generating a pulse train whose frequency is proportional to the speed of said motor, integrator means connected between said pulse transmitter means and said servoamplifier for generating said control signal having a magnitude proportional to the speed of said motor, and a rotatable drag dial for indicating maximum speed, a cam member driven from said reversible servomotor through said reduction gear arrangement, and a lifting device carrying a pin contacting said cam member so as to be driven thereby only in one direction, said lifting device being connected to said drag dial to drive said drag dial in rotation therewith.
Claim 3
Dependent Claim
86 words
An electronically controlled speedometer as defined in claim 2, wherein said servomotor includes feedback means for providing a feedback voltage proportional in magnitude to the increasing speed indication of said speed indicating dial, said feedback means being connected to said servo amplifier to provide said feedback voltage in control thereof and including an elongated resistance element having a voltage source connected thereto, said cam member carrying a wiper contacting the surface of said resistance element, said wiper being elEctrically connected to an input of said servoamplifier.
Claim 4
Dependent Claim
54 words
An electronically controlled speedometer as defined in claim 2, wherein said pulse transmitter means comprises a detector connected to said ignition coil for detecting the inductive impulses generated in said ignition coil during running of the motor, said servoamplifier, said detector, said servomotor and said integrator means being mounted on a common wiring panel.
Claim 5
Dependent Claim
61 words
An electronically controlled speedometer as defined in claim 3, wherein said reduction gear arrangement includes a drive shaft connected to said rotatable speed indicating dial and said cam member, said lifting device being freely rotatable on said drive shaft with respect to said cam member and said drive shaft, said elongated resistance element being annular and concentric with said drive shaft.
Claim 6
Dependent Claim
33 words
An electronically controlled speedometer as defined in claim 4, wherein a manual spring ratchet member is connected to said lifting device to effect selective return of said drag dial to an initial position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |