US3845375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic rotational sensor
Assignee: McLaughlin Ward and Co
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Filing: 1973-11-09
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Granted: 1974-10-29
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Expires: 1993-11-09
Abstract
Abstract A circuit for sensing the rotational rate of electric motor driving apparatus, such as a conveyor or material handler, wherein the motor driving the apparatus is deenergized upon the apparatus rate of rotation decreasing below permissible limits. A pulsating electronic signal having a frequency determined by the rotating apparatus is created by electronic light sensing means and the pulsating signal is modified to create pulses of equal duration. Charging means in the form of capacitors produce a ramp voltage at a rate proportional to the rate of apparatus rotation, and is discharged by an SCR controlled by the modified signal. Upon the ramp voltage increasing beyond a predetermined level, electronic switch means are energized operating a relay which deenergizes the motor circuit. Bypass switch means are employed to permit manual starting of the motor to obtain an operational rate of rotation.
Inventors
- 👤 A Stiebel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:08
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/10; G; G01; G01P; G01P1/00; G01P1/07; G01P1/08; G01P1/10; G01P1/103; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/4802; G01P3/481; G01P3/486; H; H02; H02H; H02H7/00; H02H7/08; H02H7/093
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
201 words
A rotation sensing electric motor control for motor driven apparatus comprising, in combination, signal producing means producing a pulsating current flow having a frequency output proportional to the rate of rotation of the apparatus driven by the electric motor to be controlled and a variable pulse width, pulse durationequalizing means connected to said frequency output equalizing the duration of the pulse widths of said frequency output, voltage charging means connected to a constant supply voltage and charging at a predetermined rate producing a ramp voltage, discharge Means connected to said voltage charging means controlling the discharge thereof and controlled by and connected to the output of said pulse duration equalizing means, ramp voltage sensing means connected to and controlled by said ramp voltage producing a control signal upon said ramp voltage attaining a predetermined value, and motor switch means connected to said ramp voltage sensing means operated by said control signal whereby said motor switch means is actuated to a motor deenergizing position upon the frequency of said pulsating current falling below the predetermined rate necessary to operate said discharge means and prevent said ramp voltage from attaining a value sufficient to produce said control signal and operate said switch means.
Claim 2
Dependent Claim
201 words
A rotation sensing electric motor control for motor driven apparatus comprising, in combination, signal producing means producing a pulsating current flow having a frequency output proportional to the rate of rotation of the apparatus driven by the electric motor to be controlled and a variable pulse width, pulse durationequalizing means connected to said frequency output equalizing the duration of the pulse widths of said frequency output, voltage charging means connected to a constant supply voltage and charging at a predetermined rate producing a ramp voltage, discharge Means connected to said voltage charging means controlling the discharge thereof and controlled by and connected to the output of said pulse duration equalizing means, ramp voltage sensing means connected to and controlled by said ramp voltage producing a control signal upon said ramp voltage attaining a predetermined value, and motor switch means connected to said ramp voltage sensing means operated by said control signal whereby said motor switch means is actuated to a motor deenergizing position upon the frequency of said pulsating current falling below the predetermined rate necessary to operate said discharge means and prevent said ramp voltage from attaining a value sufficient to produce said control signal and operate said switch means.
Claim 3
Dependent Claim
22 words
In a rotation sensing electric motor control as in claim 1, amplifying means connected to said frequency output and amplifying said output.
Claim 4
Dependent Claim
66 words
In a rotation sensing electric motor control as in claim 1 wherein said signal producing means includes light emitting means and light sensing means receiving light from said light producing means, and a light shield operated by the motor driven apparatus being controlled interrupting the light path between said light emitting and sensing means at a rate proportional to the rate of rotation of the apparatus.
Claim 5
Dependent Claim
21 words
In a rotation sensing electric motor control as in claim 1 wherein said pulse duration equalizing means comprises a monostable multivibrator.
Claim 6
Dependent Claim
31 words
In a rotation sensing electric motor control as in claim 1 wherein said charging means comprises a capacitor and said discharge means comprises an SCR connected in parallel with said capacitor.
Claim 7
Dependent Claim
56 words
In a rotation sensing electric motor control as in claim 5, first and second resistances of different values in parallel with each other and in series with said capacitor, and switch means selectively connecting one of said resistances across said capacitor to permit adjustment of the duration of the rate of increase of said ramp voltage.
Claim 8
Dependent Claim
35 words
In a rotation sensing electric motor control as in claim 1 wherein said ramp voltage sensing means includes a unijunction and an SCR and said motor switch means includes a relay operated by said SCR.
Claim 9
Dependent Claim
70 words
In a rotation sensing electric motor control as in claim 1, wherein said motor switch means includes a first relay directly controlled by said ramp voltage sensing means, a motor starter, a second relay operating said motor starter in series with said first relay, and a bypass switch directly connecting said second relay to a power source bypassing said first relay to permit the motor to attain an operating speed.
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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) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |