US3611339A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mining machine motor current meter
Assignee: Joy Manufacturing Co
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Filing: 1968-09-06
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Granted: 1971-10-05
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Expires: 1988-09-06
Abstract
Abstract A method of preventing current overloading of electrical motors of a mining machine by means of a visible output signal which flashes at a rate proportional to the variation in current flow to such motors.
Inventors
- 👤 Lee M Richey
- 👤 Melvin N Norris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:52
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/085; F; F25; F25D; F25D13/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
117 words
A method of indicating current flow to prevent overloading of rated current electrical motors of an underground mining machine comprising the steps of: energizing at least one motor of a mining machine which is operable at a rated current through an electrically energizable input circuit; deriving a signal proportional to the current flow in said input circuit; and energizing by said derived signal at least one device having a visible output signal which flashes at a rate proportional to said current flow is at least equal to said rated current and is not greater than substantially twice said rated current and is a steady visible signal when said current flow is at least twice said rated current.
Claim 2
Independent Claim
117 words
A method of indicating current flow to prevent overloading of rated current electrical motors of an underground mining machine comprising the steps of: energizing at least one motor of a mining machine which is operable at a rated current through an electrically energizable input circuit; deriving a signal proportional to the current flow in said input circuit; and energizing by said derived signal at least one device having a visible output signal which flashes at a rate proportional to said current flow is at least equal to said rated current and is not greater than substantially twice said rated current and is a steady visible signal when said current flow is at least twice said rated current.
Claim 3
Dependent Claim
25 words
A method as specified in claim 1 wherein said steady visible signal occurs when said current flow is approximately 2 1/2 times said rated current.
Claim 4
Dependent Claim
36 words
A method as specified in claim 1 wherein said first-mentioned energizing is from an alternating current source and said deriving is of an alternating current signal, and additionally rectifying said signal prior to energizing said device.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |