Method for remote control of a coal shearer
AssigneeStolar, Inc.
InventorsLarry G. Stolarczyk, David L. Baldridge
Life of this patent
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Abstract
A method for remotely controlling the mechanical functions of a coal cutting machine's electrohydraulic system which utilizes a medium frequency remote control communication system and a coal-rock interface sensor. The coal-rock interface sensor is a shielded resonant horizontal loop antenna.
Claims8
A method for controlling the thickness of a layer of coal left in a coal seam bordered by a layer of rock which comprises:
- a. calculating a control electrical conductance value;
- b. placing a sensor for measuring electrical conductance at a position near the coal seam such that said control electrical conductance value is registered by said sensor;
- c. moving said sensor transversely along said coal seam with a coal cutting drum which is positioned to cut into said coal seam at a discrete cutting depth;
- and
- d. readjusting said cutting depth of said coal cutting drum when said sensor detects a specified change in electrical conductance from said control electrical conductance value.
A method for remotely controlling the mechanical functions of a coal cutting machine's electrohydraulic system comprising:
- a. inductively coupling a medium frequency mobile transmitter to an AC power cable running to said coal cutting machine;
- b. coupling said AC power cable to a remote control unit of said coal cutting machine using a ferrite line coupler;
- c. enclosing the remote control unit and the ferrite line coupler inside of an explosion proof enclosure;
- d. encoding a command signal into a digital code format;
- e. applying the digitally encoded command signal to a frequency shift key encoder;
- f. frequency modulating a carrier frequency;
- g. transmitting the encoded command signal over the frequency modulated carrier frequency from said medium frequency mobile transmitter to said remote control unit;
- and
- h. transmitting the command signal from said remote control unit to an electrohydraulic system control unit.
A method for controlling the thickness of a layer of coal left in a coal seam bordered by a layer of rock which comprises:
- a. calculating a control electrical conductance value by:
- i. utilizing a coal cutting drum to cut through a coal seam until a layer of rock is encountered,
- ii. repositioning the coal cutting drum at a new cutting depth so that a first coal layer will be left between the layer of rock and the coal cutting drum after the coal cutting drum is advanced longitudinally into the coal seam,
- iii. advancing the coal cutting drum longitudinally into the coal seam an incremental distance,
- iv. stopping the advance,
- v. using a sensor designed to measure electrical conductance to measure a first electrical conductance value in the first coal layer,
- vi. storing the first electrical conductance value in a microcomputer,
- vii. repeating steps (ii) through (vi) so that a plurality of electrical conductance values are obtained for a plurality of coal layers having a plurality of thicknesses,
- viii. calculating the control electrical conductance value from at least some of the plurality of electrical conductance values;
- b. positioning the coal cutting drum at a cutting depth in the coal seam such that the control electrical conductance value will be registered by the sensor;
- c. moving the sensor longitudinally along the coal seam with the coal cutting drum while the coal cutting drum is cutting coal;
- and
- d. readjusting the cutting depth of the coal cutting drum when the sensor detects a specified change in electrical conductance from the control electrical conductance value.
Dependencies are inferred from the claim text.