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US3228300A - Mining apparatus - Google Patents

Mining apparatus Download PDF

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Publication number
US3228300A
US3228300A US282396A US28239663A US3228300A US 3228300 A US3228300 A US 3228300A US 282396 A US282396 A US 282396A US 28239663 A US28239663 A US 28239663A US 3228300 A US3228300 A US 3228300A
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US
United States
Prior art keywords
pressure
roof support
line
roof
conduit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US282396A
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English (en)
Inventor
Potts Michael Charles
Bolton Douglas Herbert Hewlett
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dowty Mining Equipment Ltd
Original Assignee
Dowty Mining Equipment Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dowty Mining Equipment Ltd filed Critical Dowty Mining Equipment Ltd
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Publication of US3228300A publication Critical patent/US3228300A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
    • E21D23/006—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor provided with essential hydraulic devices
    • E21D23/0073—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor provided with essential hydraulic devices with advancing shifting devices connected therewith
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
    • E21D23/006—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor provided with essential hydraulic devices
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
    • E21D23/12—Control, e.g. using remote control
    • E21D23/14—Effecting automatic sequential movement of supports, e.g. one behind the other
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8158—With indicator, register, recorder, alarm or inspection means
    • Y10T137/8326—Fluid pressure responsive indicator, recorder or alarm

Definitions

  • the roof support assembly with which this invention is concerned includes a series of roof supports distributed along the working face of a mine, and each including one or more props extendable by fluid pressure against the roof to support the same, and contractible in like manner.
  • the prop is first contracted from its normal roof-supporting condition preparatory to undergoing an advance. Its contraction, its subsequent advance, its normally ensuing extension to reset it in the advanced position against the roof, and the transmission of a signal to the next-to-be-advanced roof support, are all accomplished automatically by fluid pressure controlled by mechanism that in its details is not a part of this invention. There may be some failure to follow the normal sequence of operations, from one cause or another, and if this occurs the sequence of operations ceases.
  • the present invention is concerned, in such a system, with indicating means automatically operable to indicate a stoppage to the operator, actuated, in the form shown herein, by the existence of a predetermined pressure in a pressure line that is part of the system, for more than a predetermined period of time, whenever the series of roof supports is undergoing an advancing sequence.
  • the indicating means may indicate the existance of a maximum pressure in the pressure line for more than the predetermined time when the series of roof supports is undergoing an advancing sequence, or it may indicate the existence of a predetermined low pressure in the pressure line for more than the predetermined time when the series of roof supports is undergoing an advancing sequence.
  • the support advancing means may include a hydraulic pilot line connected to a control valve of each roof support in turn, said control valves each closing the pilot line before an advancing sequence commences, being actuated by receipt of a hydraulic-pressure signal in the pilot line from the previous support in the series, to cause its roof support to undergo an advancing operation and opening the pilot line to next support upon completion of the advancing operation of its own roof support.
  • the indicating means is of the type to indicate existence of the maximum pressure in the pressure line for more than the predetermined period of time
  • the absence of a pressure in the pilot line may be arranged to render the indicating means inoperative.
  • the indicating means may include a device responsive to pressure in the pressure line, the device being arranged to actuate an electrical circuit, including an indicating device, when the pressure reaches the predetermined value.
  • FIGURE 1 is a diagrammatic view of mining apparatus, 'but with the hydraulic connections and roof bars omitted,
  • FIGURE 2 is a similar view on a larger scale showing the hydraulic connections
  • FIGURE 3 is a diagrammatic view of the stoppage indicating means
  • FIGURE 4 is a diagrammatic view of the hydraulic control valve assembly of a roof support.
  • mining apparatus includes a conveyor 1 extending along the working face 2 of a coal mine and a cutter 3 which passes along the working face 2 and is situated between the Working face 2 and the conveyor 1.
  • the conveyor 1 acts as a guide means for the cutter 3.
  • the mining apparatus also includes a roof support assembly located on the opposite side of the conveyor 1 to the cutter 3 and working face 2.
  • the roof support assembly includes a series of roof supports 4 arranged along the working face 2,.
  • Each roof support 4 includes a groundengaging sole beam 5 carrying three hydraulicallyoperable telescopic props 6, and the three props 6 carry a roof beam (not shown).
  • Each roof support 4 is connected to the conveyor 1 by a hydraulically-operable jack '7 for advancing the roof support 4 towards the conveyor 1, and every fourth roof support 4 has a further hydraulically-operable jack 8 for advancing the conveyor 1 relative to the roof support 4.
  • the mining apparatus also includes a hydraulic power unit 9 which has a main pressure source 10 from which a hydraulic pressure line 11 and a hydraulic return line 12 extend along the working face 2.
  • Each roof support 4 includes a hydraulic control valve 13, details of which will be given later, to which the pressure line ill and return line 12 are connected by lines 14 and respectively.
  • the control valve 13 of each roof support 4 is connected to its props 6, jack 7 and jack 8 (if provided).
  • the control valve 13 of each roof support provided with a jack 8 is so arranged that the jack 8 is urging the conveyor 1 towards the coal face continually except when the roof support 4 is being advanced. Actuation of the control valve 13 causes the following operations to take place in sequence:
  • Actuation of the control valves 13 is caused by a hydraulic pilot system.
  • the power unit 9 includes a source which in FIGURE 2 is designated 16, of hydraulic pressure for the pilot system, and a pilot line 17 extends from the pilot source 16 and passes through the control valve 13 of each roof support 4 in turn. Each control valve initially closes the pilot line 17.
  • the pilot source 16 is operated to pressurise the pilot line 17, the hydraulic pressure in the pilot line 17 acts as a signal to the control valve 13 of the first roof support 4.
  • This roof support 4 undergoes an advancing operation, as described above and when the roof support has been satisfactorily reset against the roof, the satisfactory resetting being sensed by the attainment of a desired hydraulic pressure in the props 6, the control valve 13 is caused to 3 open the pilot line so that the hydraulic pressure signal is then applied to the control valve 13 of the next roof support, which then undergoes an advancing operation.
  • each roof support in turn undergoes an advancing operation.
  • the hydraulic circuit relating to the advancing sequence is described in United States application Serial No. 282,760, filed May 23, 1963, and in United States application Serial No. 355,769, filed March 30, 1964.
  • valve assembly 13 of each roof support 4 includes six valve units A, B, C, D, E and F.
  • Valve unit A controls the supply of hydraulic fluid to the jack 8 in a jack-extending sense and is connected to the branch supply line 14 and to a line 53 leading to the jack 8.
  • Valve unit B is connected to the line 53 and to the branch return line 15.
  • Valve unit D controls the supply of hydraulic fluid to the jack 7 and jack 8 in a jack-contracting sense and is connected to the branch supply line 14 and to a line 54 leading to the jacks 7 and 8.
  • Valve unit C is connected to the line 54 and to the branch return line 15.
  • Valve unit E controls the supply of hydraulic fluid to the props 6 and is connected to the branch supply line 14 and to the props 6 through a line 55 including a restrictor 56 and a non-return valve 57.
  • Valve unit F controls the release of hydraulic fluid from the props 6 and is connected to a line 58 leading from the props 6 and to the branch return line 15.
  • the line 58 includes a nonreturn valve 59, and a pressure relief valve 61 is connected in parallel with the valve unit F between the line 58 and the branch return line 15.
  • valve units A and B are associated with a pivotallymounted lever 62 which is connected to a similar lever 63 associated with the valve units C and D.
  • the levers 62 and 63 coordinate the action of valve units A, B, C and D. In those roof supports without a double-acting jack 8, valve units A and B and lever 62 are omitted.
  • the action of valve units E and F are coordinated by a pivotally-mounted lever 64.
  • the levers 62, 63 are ganged to one another as shown by the connection 60.
  • the valve assembly of each roof support 4 includes a pilot valve 65 which, before an advance of the roof support begins, closes the pilot line 17.
  • the pilot valve 65 includes a valve member 66 urged towards a valve seat 67 by a spring 68, and also includes a piston 69 carrying a piston rod 71.
  • the piston 69 can be moved against the force exerted by a spring 72 by a sufiicient hydraulic pressure in a line 73 to cause the piston rod 71 to lift the valve member 66 off the valve seat 67.
  • the line 73 is connected to line 55.
  • the piston rod 71 has a bore 75 which, when the piston rod 71 is not engaging the valve member 66, brings one side of the valve member 66 into communication with the branch return line 15. When piston rod 71 engages the valve member 66, the valve member 66 closes the bore 75.
  • non-return valves 76 are connected in the pilot line 17 to enable the roof support to be caused to undergo an advancing operation by the receipt of a signal along pilot line 17 from the adjacent left hand roof support or from the adjacent right hand roof support.
  • a small restrictor 74 is connected in the pilot line 17 across pilot valve 65 to ensure that pressure cannot be trapped in the portion of pilot line 17 between valves 76 and valve unit C by providing a leak to the branch return line through the bore 75 in piston rod 71.
  • a prop resetting valve 83 is associated with the support-advancing jack 7.
  • the resetting valve 83 includes a valve member 84 urged by a spring 85 into a valve seat 86 to isolate the chamber 87 of the jack 7 from a line 88 connected to valve unit F and to line 55 through a nonreturn valve 89.
  • a lifter rod 91 can be moved to lift the valve member 84 oif its seat 36, as the jack 7 becomes contracted to the full extent intended, by a trip 93 carried by the piston rod 94 of the jack 7.
  • FIGURE 1 shows the cutting machine 3 traveling from left to right along the working face 2. After the cutting machine 3 has passed the first few roof supports 4 in the series, it is necessary to advance the conveyor 1 in front of these roof supports 4 and then to advance the roof supports 4.
  • Each roof support 4 having a conveyoradvancing jack 8 is operated to cause the jack 8 to apply an advancing force to the conveyor 1, the roof support 4 being set against the roof and acting as an anchorage.
  • pivoting lever 62 is an anticlockwise direction to open valve unit A and thus pressurizing the line 53 and the pushing side of jack 8. This movement of the lever 62 may be caused by manual operation of lever 62 or by pressurization of a hydraulic line 95 connected to valve unit B.
  • the line 95 may be connected through a manually or remotely controlled valve to the main supply line 11.
  • a springoperated latch 96 holds the lever 62 in this position.
  • the anticlockwise movement of lever 62 causes a similar movement of lever 63, but such movement does not change the state of valve units C and D from that shown in FIGURE 4.
  • the latch 96 is connected to the pilot line 17 in such a manner that pressurization of the pilot line 17 releases the latch 96 so that valve unit A closes and returns lever 62 and consequently lever 63 to the position in FIGURE 4.
  • the roof supports 4 can then be advanced.
  • the source 16 is operated to pressurize the pilot line 17 and hence a hydraulic pressure signal is sent along line 17 to the first roof support 4.
  • the hydraulic pressure signal reaches the roof support through the portion of line 17 shown in the upper left-hand part of FIGURE 4.
  • the hydraulic pressure signal releases the latch 96 and operates on valve unit C to cause clockwise movement of levers 62 and 63.
  • valve unit A closes, valve unit B opens, valve unit C closes and valve unit D opens.
  • the pushing or jack-extending side of jack 8 is connected to the branch return line 15, and the jackcontracting sides of the jacks 7 and 8 are connected through the line 54 with the branch supply line 14.
  • the conveyor-advancing jack 8 is not actually connected to the conveyor 1 but merely pushes against the conveyor 1 when applying an advancing force to it. Therefore, at this stage, the jack 8 contracts and takes no part in advancing the support.
  • Line 54 is also connected by a line 99 to valve unit F, and the pressurization of line 54 causes the valve unit F to be opened to bring the line 58 into communication with the branch return line 15, thus releasing the hydraulic pressure in the props 6 and so releasing the roof support 4 from the roof.
  • the jack 7 then contracts and advances the roof support 4 towards the conveyor 1 with the conveyor 1 acting as an anchorage.
  • the hydraulic pressure in line 88 is also present in line 73.
  • this value of pressure is arranged to operate on the piston 69 and to open pilot valve 65.
  • the portion of the pilot line 17 between the control valve 16 and the first roof support 4 is brought into communication with the portion of the pilot line 17 between the first roof support and the second roof support (that is the portion of the pilot line 17 in the lower left portion of FIGURE 4) with the result that the hydraulic pressure signal in the pilot line 17 reaches the second roof support in the series and causes it to undergo an advancing operation. In this way, each roof support in the group in advanced in turn.
  • valve assembly 13 If it is desired to operate the valve assembly 13 manually, this can be done by manually operating levers 62, 63, 64.
  • This invention adds to the hydraulically operated basic system for automatic sequential advance of the roof supports a means to indicate a stoppage in an advancing sequence, as a result of some fault or abnormality; for it is most important that the operator be warned so that he can take necessary corrective or precautionary measures at once, leading eventually to correction of the fault and resumption of the automatic sequential advance of the roof supports in the series. Absent such warning, the mine roof lacks support as near as possible to the working face.
  • roof supports do not advance when they should, operation of the cutter 3 and the conveyor 2 may have to be stopped immediately, and thus it is important, in carrying out the mining operation safely, that a stoppage in an advancing sequence should be brought to the attention of an operator soon as possible.
  • the pressure in the main pressure line 11 will fluctuate as the various props and jacks are operated in the sequence, and maximum pressure, if attained at all during an advancing sequence, will only be attained for short periods.
  • the pressure in the pressure line 11 will only be able to build up to and remain at maximum pressure, during an advancing sequence, if the advancing sequence stops before it is completed, for example by reason of a fault in a roof support or an obstruction preventing the advance of a roof support.
  • a sequence stoppage indicating means 18 includes a pressure gauge 19 which is connected to the main pressure line 11 so as to indicate the pressure in it.
  • the pressure gauge 19 has a pointer 21, which forms a movable contact in an electrical circuit.
  • a fixed contact 22 is located in the pressure gauge 19 at a position which corresponds to the position of the pointer 21 when the pressure in the pressure line 11 is the maximum.
  • the electrical circuit also includes a battery 23 and an audible and/ or visual warning device 24 which includes a conventional false start time delay and relay so that the device 24 is only actuated if the circuit is closed for more than a predetermined period of time, for example thirty seconds.
  • a hydraulic-pressure-operated electrical switch 25, biased to open, is also included in the electrical circuit and is connected to the pilot line 17 by a hydraulic line 26, so that a pressure in the pilot line 117 will be transmitted to the switch 25 so as to close it.
  • the pilot line 17 When an advancing sequence is taking place, the pilot line 17 is pressurized and this pressure is transmitted along line 26 to close switch 25. Each time the pressure in the pressure line 11 reaches the maximum, the pointer 21 engages the contact 22 and completes the circuit. However, temporary attainments of maximum pressure which may occur in the pressure line 11 during an advancing sequence will not cause the closure of the circuit since the time delay device at 24 permits closure only if the maximum pressure persists for more than the pre determined period of time.
  • the warning device 24 only operates if, during an advancing sequence, the pressure in the pressure line 11 remains at maximum for more than the predetermined period of time. As explained above, this can only happen if the advancing sequence stops before it is completed and, therefore, the operator is warned of such an event.
  • an advancing sequence may stop. Such a leakage will cause the pressure in the main pressure line 11 to fall to and remain at a low value.
  • the pressure in the pressure line 11 may fall to such a low value for short periods during an advancing sequence, for example when the props 6 are being reset, and, therefore, only a low pressure for more than a predetermined period of time will indicate failure of the hydraulic system by leakage or failure of the power unit 10.
  • the pressure gauge 19 includes a contact 27 which is engaged by the pointer 21 if the pressure line 11 falls below a predetermined value.
  • the contact 27 is connected to the warning device 24 by a connection which bypasses the switch 25. Therefore, the circuit to the warning device 24 will be completed eace time the pressure in the pressure line falls to the predetermined low value, but due to the delay included in the device at 24, the Warning device 24- will only operate if the low pressure is present for more than the predetermined period of time.
  • the operation of the warning device 24 by the occurrence of low pressure in the pressure line 11 is independent of the switch 25, that is to say if low pressure occurs for more than the predetermined period of time, the warning device 24 will operate whether an advancing sequence was in progress or not.
  • a roof support assembly including a series of fluidpressure-operated advanceable roof supports, a source of fluid pressure, a conduit connecting said source with each roof support, each roof support including at least one fluid-pressure-operated prop to which said conduit is connected, and a fluid-pressure-operated means to advance it also connected to said conduit, and a control valve assembly individual to each roof support and operable to supply pressure fluid from such source to cause its roof support to undergo an advancing operation, each control valve assembly being arranged to send a signal to the control valve assembly of the next roof support, to initiate advance thereof, upon completion of the advance of its own roof support, a Warning device including a pressuresensitive means operatively connected to said conduit, and operable by departure of pressure therein from its normal range fluctuation occurring during an advancing operation, to indicate interruption of such operation, and time delay means operatively connected to said indicating means to delay its indication during such normal pressure fluctuations, but effecting such indication in the event of a continuing abnormal pressure in said conduit.
  • a roof support assembly including a series of fluidpressure-operated adva'nceable roof supports; a main source and a pilot source of fluid pressure; a main pressure conduit pressurized from said main source and operatively connected to the several roof supports to effect their advance; each roof support including at least one fluid-pressure-operated prop to which the main pressure conduit is connected, and a control valve operable to cause its roof support to undergo an advancing operation; a pilot pressure conduit operatively connected between the pilot pressure source and the control valves of the several roof supports in sequence; each control valve being arranged to send a fluid pressure signal along the pilot pressure conduit from its own roof support to the control valve of the next roof support, upon completion of the advancing operation of its own roof support, to initiate an advancing operation of the next roof support; a warning device connected to the main pressure conduit and operable by departure or pressure therein from its normal range of fluctuation occurring during an advancing operation, to indicate interruption of such advancing operation; and means operatively connected to said warning device to delay its indication during normal pressure fluctuations, but
  • warning device includes pressure-sensitive means shiftable under the influence of pressure in the main pressure conduit, from a null position towards a maximum position, but arranged to remain between such positions under the influence of normal pressure fluctuations in said main pressure conduit during an advancing operation, and a warning signal arranged for operation by said pressuresensitive means upon its reaching its maximum position under the influence of maximum pressure in the main pressure conduit occurring as a result of stoppage of an advancing operation.
  • Warning device includes means operable by the pressuresensitive means when the latter is in its null position, and arranged to operate the warning signal when the pressure sensitive means remains for a predetermined period of time in its null position.
  • a roof support assembly as in claim 2 including a connection from the pilot pressure conduit to the Warning device, said warning device including a pressure gauge movable from a 'null position towards a maximum position by pressure in the main pressure conduit, an electrically operable warning signal, an electric circuit including a switch closable by the pressure gauge in its maximum position, and also including the time delay means and the warning signal, and a switch in said circuit biased to open, but arranged to be closed by pressure in the pilot pressure conduit.
  • a roof support assembly as in claim '7 the circuit also including a switch arranged to be closed by the pressure gauge when the latter is in its null position, and a by-pass connection from said latter switch directly to the time delay means and the warning signal, by-passing the pilot-pressure'operated switch, to energize the warning signal by the pressure drop in the main pressure conduit when no advancing operation is occurring.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Control Of Conveyors (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Measuring Volume Flow (AREA)
  • Lining And Supports For Tunnels (AREA)
US282396A 1962-05-25 1963-05-22 Mining apparatus Expired - Lifetime US3228300A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB20198/62A GB991007A (en) 1962-05-25 1962-05-25 Mining apparatus

Publications (1)

Publication Number Publication Date
US3228300A true US3228300A (en) 1966-01-11

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US282396A Expired - Lifetime US3228300A (en) 1962-05-25 1963-05-22 Mining apparatus
US282412A Expired - Lifetime US3217603A (en) 1962-05-25 1963-05-22 Mining apparatus

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Application Number Title Priority Date Filing Date
US282412A Expired - Lifetime US3217603A (en) 1962-05-25 1963-05-22 Mining apparatus

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US (2) US3228300A (de)
DE (2) DE1189504B (de)
FR (2) FR1356892A (de)
GB (2) GB991012A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3318328A (en) * 1965-05-26 1967-05-09 Combustion Eng Alarm system
US3320858A (en) * 1963-06-21 1967-05-23 Dowty Mining Equipment Ltd Roof support assemblies
US3379099A (en) * 1965-10-22 1968-04-23 Botalam Installation for the automatic control of hydraulic jacks or like devices
US3381581A (en) * 1964-10-12 1968-05-07 Carnegie James Roof support assembly having electrically operated signalling means
US3455329A (en) * 1966-08-05 1969-07-15 Gabriel Roth Pneumatic indicating device
US3589241A (en) * 1966-10-14 1971-06-29 Dowty Mining Equipment Ltd Mine roof support systems

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1022469A (en) * 1964-02-11 1966-03-16 Dowty Mining Equipment Ltd Roof support assembly suitable for use in mines
GB1126902A (en) * 1964-10-22 1968-09-11 Fairey Eng Improvements relating to hydraulic control systems
US3657964A (en) * 1969-07-14 1972-04-25 Gardner Denver Co Control system for nutsetter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US758819A (en) * 1902-10-28 1904-05-03 Robert G Callum Electric system for indicating the temperature of a distant point.
US2749536A (en) * 1953-09-16 1956-06-05 Sperling Gustav Electrically operated leak detector
US2959156A (en) * 1956-08-03 1960-11-08 Sarl Ratier Aviat Marine Hydraulic servo-device for controlling linearly or rotatably movable members, with indication of the position thereof
US3045627A (en) * 1956-05-24 1962-07-24 Robert C Eck Depth control system

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1312787A (en) * 1919-08-12 Intermittent-grip device
DE1069548B (de) * 1959-11-26
US627661A (en) * 1899-01-06 1899-06-27 Wilson E Symons Emergency-recorder for air-brakes.
US2711634A (en) * 1949-05-25 1955-06-28 Joy Mfg Co Mine roof supporting means
US2753036A (en) * 1952-03-06 1956-07-03 Joy Mfg Co Mine roof support-equipped mining apparatus
AT184539B (de) * 1954-04-12 1956-01-25 Kloeckner Bergbau Victor Icker Wandernder Ausbau mit durch ein Druckmittel betätigten Ausbaugespannen
FR1201174A (fr) * 1957-08-10 1959-12-29 Gewerk Eisenhuette Westfalia Procédé et dispositif pour la commande d'un soutènement hydraulique, utilisable notamment dans les mines
DE1109629B (de) * 1958-09-20 1961-06-29 Hoesch Bergbautechnik G M B H Anordnung zum mechanisierten Strebausbau

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US758819A (en) * 1902-10-28 1904-05-03 Robert G Callum Electric system for indicating the temperature of a distant point.
US2749536A (en) * 1953-09-16 1956-06-05 Sperling Gustav Electrically operated leak detector
US3045627A (en) * 1956-05-24 1962-07-24 Robert C Eck Depth control system
US2959156A (en) * 1956-08-03 1960-11-08 Sarl Ratier Aviat Marine Hydraulic servo-device for controlling linearly or rotatably movable members, with indication of the position thereof

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3320858A (en) * 1963-06-21 1967-05-23 Dowty Mining Equipment Ltd Roof support assemblies
US3381581A (en) * 1964-10-12 1968-05-07 Carnegie James Roof support assembly having electrically operated signalling means
US3318328A (en) * 1965-05-26 1967-05-09 Combustion Eng Alarm system
US3379099A (en) * 1965-10-22 1968-04-23 Botalam Installation for the automatic control of hydraulic jacks or like devices
US3455329A (en) * 1966-08-05 1969-07-15 Gabriel Roth Pneumatic indicating device
US3589241A (en) * 1966-10-14 1971-06-29 Dowty Mining Equipment Ltd Mine roof support systems

Also Published As

Publication number Publication date
GB991012A (en) 1965-05-05
GB991007A (en) 1965-05-05
FR1356891A (fr) 1964-03-27
DE1189504B (de) 1965-03-25
US3217603A (en) 1965-11-16
FR1356892A (fr) 1964-03-27
DE1176087B (de) 1964-08-20

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