US4120534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for controlling the steering mechanism of a mining machine
Assignee: Coal Industry Patents Ltd
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Filing: 1976-11-30
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Granted: 1978-10-17
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Expires: 1996-11-30
Abstract
Abstract Apparatus for controlling the steering mechanism of a mineral mining machine having a nucleonic sensor adapted to sense the cutting horizon of the machine's cutter head relative to a boundary of the mineral seam, the apparatus providing an electronic cavity detector which freezes the machine's steering mechanism according to two operational modes when a cavity or crack/undulation respectively is detected. Thus, the machine is not steered in accordance with an erroneous sensor signal derived when the sensor is adjacent to the cavity or crack/undulation.
Inventors
- 👤 George Thomas Addison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:30
CPC Classifications
E; E21; E21C; E21C35/00; E21C35/282; E21C35/302
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
133 words
Apparatus for controlling the steering mechanism of a mining machine having a detector for sensing the cutting horizon of the machine relative to the boundary of a mineral seam when the machine is mining in the seam, comprising first electrical means having a relatively long time constant for normally controlling the machine's steering mechanism in response to the detector's output signal, second electrical means having a time constant which is relatively short compared to the time constant of said first electrical means for overriding said first electrical means should the detector output signal reach a preselected condition, and third electrical means sensitive to a transient difference between the outputs of said first and second electrical means, said third electrical means overriding the first electrical means when the transient difference exceeds a preselected amount.
Claim 2
Dependent Claim
133 words
Apparatus for controlling the steering mechanism of a mining machine having a detector for sensing the cutting horizon of the machine relative to the boundary of a mineral seam when the machine is mining in the seam, comprising first electrical means having a relatively long time constant for normally controlling the machine's steering mechanism in response to the detector's output signal, second electrical means having a time constant which is relatively short compared to the time constant of said first electrical means for overriding said first electrical means should the detector output signal reach a preselected condition, and third electrical means sensitive to a transient difference between the outputs of said first and second electrical means, said third electrical means overriding the first electrical means when the transient difference exceeds a preselected amount.
Claim 3
Dependent Claim
15 words
Apparatus as claimed in claim 1, wherein the third electrical means comprises a comparator arrangement.
Claim 4
Dependent Claim
30 words
Apparatus as claimed in claim 1 comprising means for retaining the machine's steering mechanism in a set position when the first electrical means is overridden by the second electrical means.
Claim 5
Dependent Claim
31 words
Apparatus as claimed in clam 3, wherein said retaining means retains the machine's steering mechanism in a set position when said first electrical means is overridden by said third electrical means.
Claim 6
Dependent Claim
39 words
Apparatus as claimed in claim 1, wherein the second electrical means effectively short circuits at least a part of the first electrical means momentarily to reduce its time constant when the detector output signal falls below the preselected amount.
Claim 7
Dependent Claim
38 words
Apparatus as claimed in claim 1, wherein the third electrical means effectively short circuits at least a part of the first electrical means to reduce momentarily its time constant when the transient difference falls below a preselected amount.
Claim 8
Dependent Claim
107 words
A probe for controlling the steering mechanism of a mining machine including apparatus comprising first electrical means having a relatively long time constant for normally controlling the machine's steering mechanism in response to an input signal, second electrical means having a time constant which is relatively short compared to the time constant of said first electrical means for overriding said first electrical means should said input signal reach a preselected condition, and third electrical means sensitive to a transient difference between the outputs of said first and second electrical means, said third electrical means overriding said first electrical means when the transient difference exceeds a preselected amount.
Claim 9
Dependent Claim
107 words
A probe for controlling the steering mechanism of a mining machine including apparatus comprising first electrical means having a relatively long time constant for normally controlling the machine's steering mechanism in response to an input signal, second electrical means having a time constant which is relatively short compared to the time constant of said first electrical means for overriding said first electrical means should said input signal reach a preselected condition, and third electrical means sensitive to a transient difference between the outputs of said first and second electrical means, said third electrical means overriding said first electrical means when the transient difference exceeds a preselected amount.
References Cited (Backward Citations)
US3351385A
Cited
US3817578A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-16 | 1982-04-17 | 1982-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-16 | 1986-04-17 | 1986-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-16 | 1990-04-17 | 1990-10-17 | $7700.00 | Window Closed / Lapsed |