US2803444A - Mine roof support systems - Google Patents

Mine roof support systems Download PDF

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Publication number
US2803444A
US2803444A US566712A US56671256A US2803444A US 2803444 A US2803444 A US 2803444A US 566712 A US566712 A US 566712A US 56671256 A US56671256 A US 56671256A US 2803444 A US2803444 A US 2803444A
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Prior art keywords
prop
roof
unit
conveyor
support
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Expired - Lifetime
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US566712A
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English (en)
Inventor
Potts Michael Charles
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Dowty Mining Equipment Ltd
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Dowty Mining Equipment Ltd
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    • 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
    • E21D23/0052—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor 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
    • E21D23/08—Advancing mechanisms
    • E21D23/081—Advancing mechanisms forming parts of the roof supports
    • E21D23/085—Advancing mechanisms forming parts of the roof supports acting on a conveyor or a guide for the mining machine
    • 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
    • E21D23/16—Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices

Definitions

  • This invention relates to a method of and apparatus for supporting the roof of a coal mine in conjunction with coal cutting and conveying machinery constructed for mining operations by the long wall method.
  • the term coal cutting machinery is used to comprehend cutter loaders, coal ploughs and the like which are arranged to traverse the long wall.
  • One object of the invention is to provide an improved system of support for the mine roof behind the newly cut face, while a related object is to reduce the time interval in the setting of the individual supports in this position.
  • Another object is to provide improved regulation in the controlled collapse of the mine roof behind the supports, and in particular to the determination of a uniform break-line behind which the roof may collapse after the removal of the support therefrom.
  • the method in a method of supporting the roof of a coal mine during long wall mining operations utilizes a plurality of extensible support units of two kinds disposed alternately along the coal face in connective association with an extended structure such as a conveyor framework, and each unit being constructed to provide extended support for the mine roof behind and over the structure; the method comprising the steps of releasing and advancing the support units of the first kind successively towards the newly cut face when the coal cutter has passed clear in its progress along the face, extending each unit so advanced to support the newly exposed roof, advancing the structure progressively towards the newly cut face in the wake of the coal cutter, releasing and advancing the support units of the second kind successively into alignment with the advanced support units of the first kind after the adjacent part of the structure has advanced fully to the position required for the next traverse of the coal cutter, and extending each unit so advanced to support the roof between the support units of the first kind.
  • the apparatus for carrying the method into effect comprises a plurality of support units each having a vertically adjustable roof bar, and being of two kinds disposed alternately in connective association with the structure, with their roof bars extending transversely thereto, the roof bars having forward cantilever extensions which are longer in the first kind of support unit than in the second so as to be capable of being advanced to a position in which they support the newly exposed roof in the wake of the coal cutter before the structure to which the units are connected can be advanced, and a feed jack forming the connection between the structure and each support unit for effecting relative movement between them.
  • the structure, to which the support units are connected may be the framework of a conveyor which is installed along the coal face, the framework being articulated or otherwise inherently fiexible so it can be advanced progressively over a part of its length.
  • the important thing is not that the supports be connected to a conveyor frame,
  • Figure l is a diagram in plan view of the roof support systems in the mine, shown in simple form to illustrate the manner of operation;
  • Figure 2 is an isometric view of part of a conveyor with the roof supports which are associated with that p Figure 3 is a side elevation of the forward end of a roof support unit and its connection to the conveyor, certain parts of the support unit being broken away to show interior details, and
  • Figure 4 is a hydraulic diagram to illustrate the working of the hydraulic components of each unit.
  • the coal face is shown at 10 on the lefthand side and the newly exposed coal face 11 at the centre and right, while a power-operated cutter loader 12 is moving to the left to extend the newly exposed face 11.
  • the cutter loader 12 is guided by a conveyor 13 which extends in a straight line along the coal face being cut and adjacent the cutter loader 12, but it snakes forwardly behind the cutter loader and lies in a straight line along the newly exposed face 11 at the right-hand side of the diagram.
  • Each roof support unit of the first kind 14 comprises a roof bar 15 supported by two hydraulic props 16 and will hereinafter be termed a two prop unit.
  • Each roof support unit 17 of the second kind comprises a roof bar 18 supported by three hydraulic props 19 and will hereinafter be termed "a three prop unit.
  • a cantilever portion of each roof bar extends forwardly over the conveyor, the cantilever extension 21 on each two prop unit 14 being longer than the cantilever 22 on each three prop unit 17.
  • the length of the cantilever 21 is such as to enable each two prop unit to be advanced towards the newly exposed face once the cutter loader 12 has passed it, while the length of the cantilever 22 of each three prop unit is such that the latter can only be advanced towards the newly exposed face 11 when the adjacent part of the conveyor has also been advanced towards the newly exposed face, the limitation of advance of the three prop unit being imposed by the proximity of the forward prop 19 of each unit 17 to the conveyor.
  • each three prop unit is better adapted to support the mine roof over the length of the roof bar, the provision of two prop units 14 alternating with them does enable a substantial degree of support to be given to the newly exposed roof in the wake of the cutter loader 12 by immediately advancing each two prop unit 14 as the cutter loader 12 passes.
  • Each roof support unit is connected to the conveyor 13 by means of a hydraulic jack, and this connection together with details of the construction of each unit will now be described with reference to Figures 2 and 3.
  • the three prop unit 17 shown in the foreground of Figure 2 comprises a box-section base member 23 whose lower face is formed as a skid plate 24.
  • a rear prop 25 and intermediate prop 26 are each socketed into the base member 23, while a front hydraulic prop 27 is similarly socketed into a bucket-shaped mounting 28 which surmounts the forward end of the base member 23.
  • the base of the prop 27 is of shallow convex form and has a central spigot 29 projecting loosely into a central aperture 31 at the base of the mounting 28.
  • a collar 32 of rubber or like material surrounds the base portion of the prop 27 and it is raised within the mounting 28 by a distance piece 33 which rests on the bottom of the mounting.
  • the prop 27 can thus rock to a certain extent from the vertical but is centralized by the rubber collar 32. Dirt is prevented from entering the mounting by a two-part shield plate 34 fitting around the prop, and whose front and rear edges.
  • the telescopic portion 37 of the prop has a shallow convex cap 38 bearing within the roof bar 18 which is of inverted channel shape.
  • a bearing plate 39'for the cap 38 is secured by a bolt 41 having a conical head 42 which extend with clearance through a central conical aperture 43 in the cap 38;
  • the bolt 41 thus locates the head of the prop but permits limited angular movement to take place between the prop 27 and roof bar 18 as may arise when the props are engaged in thrust between a mine roof and floor which are not strictly parallel or which have other irregularities.
  • the rear prop 25 and intermediate prop 26 are mounted at their bases and top caps in similar manner, though the mountings for the bases are actually within the box-section base member 23.
  • the mounting 28 for theforward prop 27 is arranged above the base member to allow the installation of a feed jack within the cavity in the forward part of the base member 23.
  • This feed jack 44 shown in Figure 3 is double-acting and comprises a cylinder 45 whose forward end is held by vertical pivots 46 (see Figure 3) in a gimbal ring 47, the gimbal ring being supported in turn by transverse pivots 48 which project through opposite sides 49 of the box-section base member 23.
  • the piston rod 51 extending from the cylinder 45 has a forked head 52 secured by a transverse pivot 53 on a block 54 which is in turn pivoted on a pin 55 mounted vertically in the side of the conveyor 13.
  • the pin 55 is supported at its ends in a channel 56 at the side of the conveyor 13.
  • the cylinder 45 and piston rod 51 are thus connected by universal joints to the base member 23 and conveyor 13 respectively which allow for angular misalignment, while the length of the pin 55 exceeds the height of the block 54 to allow for changes in level between the conveyor and the base member 23.
  • the piston rod 51 is substantially protected by means of an extensible shield 57 comprising an inverted channel-shaped plate having slotted cars 58 engaged by a transverse pin 59 in the head 52 of the piston rod.
  • the shield slides with the piston rod in the open forward end of the base member 23 and at all times covers the piston rod 51 from above.
  • each two prop unit is basically similar except that it has a shorter base member 61 having only two props, the front prop 62 being held in a mounting 63 which surmounts the base member 61, and a rear prop 64 which is socketed into the rear end of the base member.
  • the roof bar 15 is, nevertheless, of the same length as the roof bar 18 of each three prop unit and is connected to the heads of the props 62 and 64 as described with reference to Figure 3.
  • the base member 61 has the cylinder of a feed jack secured thereto by a gimbal hearing as in the three prop unit and the piston rod 65, visible in Figure 2, is connected to a pin 66 on the side of the conveyor 13 by a universal joint as shown in Figure 3.
  • the piston rod is likewise protected by a shield 67 though this shield has a number of transverse holes 68into a selected one of which a stop bar 69 may be inserted for a purpose which will be described.
  • the distance between the front and rear props 62 and. 64 is equal to that between the front and intermediate props-27 and 26 of the three prop unit while the distance between the intermediate and rear props 26 and 25 of the latter is substantially equal to the maximum advancingmovement of each unit as provided by the feed jack.
  • the power for operating the feed jacks 45 and for settmg the props is supplied by ahydraulic power unit, not shown, which. supplies two pressure mains 71 and 72 and receives a return main 73, .all three of which extend, along.
  • One pressure main 71 supplies power for the three prop units while the other pressure main 72 supplies power for two prop units, but if desired a single pressure main can supply all the units.
  • the supply and return of hydraulic fluid to each feed jack 44 is by way of a selector valve 74 mounted on the side of the conveyor, this valve 74 being operable by a control shaft 75 into which a Tommy bar for turning the shaft may be inserted.
  • Each support unit has a pressurizing valve and a release valve disposed thereon behind the mounting 28 for the front prop, the pressurizing valve being operable by a control shaft 76 and the release valve being operable by a control shaft 77, Figure 2.
  • the selector valve 74 has valve plungers 78 and 79 shiftable by a rocker 81 on the control shaft 75 and loaded towards the rocker by springs 82 and 83 respectively. In the central position of the rocker 81, the plungers 78 and 79 close a pressure port 84 which is connected by a passage 85 with the pressure main 71.
  • the piston rod 51 of the feed jack 44 has a tubular insert 93 dividing a central passage 94 which is connected by line 95 with the feed port 86, from an outer passage 96 which is connected by line 97 with the feed port 87.
  • the central passage 94 opens through the piston 98 into the piston chamber 99 of the jack while the outer passage 96 opens through an aperture 101 in the piston rod 51 into the rod chamber 102.
  • a block 103 is situated adjacent the jack 44 and has a check valve 104 therein permitting flow from the rod chamber 102 through a connecting line 105 to another line 106 which is connected to the inlet 107 of the pressurizing valve 108.
  • the pressurizing valve 108 has a spring-loaded plunger 109 which may be lifted by a cam 111 on the control shaft 76 to open the inlet port 107 to an outlet port 112.
  • the outlet port 112 is connected by way of a branched line 113 with three check valves 114, 115, 116 which permit flow through lines 117, 118 and 119 into the hydraulic jacks 27, 26, 25 respectively.
  • the check valves 114, 115, 116 are contained in a block 121 which houses three further check valves 122, 123 and 124 which permit flow through the lines 117, 118 and 119 from the props 27, 26 and 25 respectively into a branched line 125.
  • the branched line 125 is connected to an inlet port 126 of a relief valve 127 which is operable also as a release valve by means of a cam 128 on the control shaft 77, and a spring-loaded valve plunger 129.
  • the inner end of the-valve plunger 129 contains a spring-loaded relief valve 131 which opens under excessive pressure in the branched line 125 from any of the props 27, 26 or 25, to allow liquid to escape to the outlet port 132 of the valve 127. Alternatively all three props can be released at will by turning the control shaft 77 and cam 128 to lift the plunger 129.
  • the outlet port 132 is connected by a line 133 with two further check valves 134 and 135 in the block 103, the valve 134 permitting flow into the line 105 which is connected with the rod chamber 102 of the jack cylinder 45, and the valve 135 permitting flow into a line 136 which is connected with the piston chamber 99.
  • the check valves 134 and 135 permit escape of pressure liquid at all times from the relief valve into either jack chamber 99 or 102, whichever is at low pressure, and thence through line 95 or 97 and the selector valve 74 to the return main 73.
  • the check valve 104 in the block 103 admits liquid from the rod chamber 102, when this is under pressure, to the pressurizing valve 108, and when the latter is operated, liquid may pass in the manner described to all three jacks 27, 26 and 25, and enable the roof bar carried thereby to be set against the roof of the mine.
  • Each two prop unit has a feed jack, a pressurizing valve and a relief valve incorporated in a hydraulic circuit as described with reference to Figure 4 with the exception there are two hydraulic props instead of the three illustrated.
  • the feed jack of the two prop unit shown in Figure 2 has a control shaft 75a part of which is seen, a control shaft 76a for the pressurizing valve and a control shaft 77a for the release valve therein.
  • the two and three prop units behind the coal face about to be cut are in line with their cantilevers 21 and 22 respectively overlying the conveyor which in that region is adjacent the coal face.
  • the feed jacks 44 on each two prop unit will be fully extended while the feed jacks of the three prop units will be fully contracted.
  • the operator turns the control shaft 77a of the release valve to allow the roof bar to fall clear of the mine roof, and by then turning the control shaft 75a of the selector valve, hydraulic pressure may be admitted into the rod chamber 102 of the feed jack 44 to contract the prop and thus enable the two prop unit to draw itself forwardly on the conveyor 13.
  • the amount of feed may be determined by placing the stop bar 69 in an appropriate hole 68 in the shield 67 so that forward movement is limited by engagement of the forward end of the base member 61 with the stop bar 69.
  • the operator While pressure is maintained in the rod chamber 102 of the jack 44, the operator turns the control shaft 76a of the pressurizing valve to cause pressure liquid to enter the hydraulic props 62 and 64 and thus reset the roof bar 15 against the mine roof.
  • the two prop units of Figure 1 shown in the wake of the cutter loader 12 are all in this advanced position up to the unit shown at 14a.
  • the operator turns the control shaft 75a of the selector valve into its neutral position so that both chambers of the jack 44 are at return pressure.
  • the rear props 64 of the two prop units will be in line with each other and with the intermediate props 26 of the three prop units.
  • the thrust in the latter will tend to initiate a roof crack along the line of the rear props 64, so that when each three prop unit is subsequently advanced the roof will tend to subside uniformly behind the predetermined line of the initial roof crack.
  • the next step is to advance the part of the conveyor 13 6 behind the cutter loader progressively forward in a snaking movement, which the operator does by turning the control rod 75 of each selector valve to admit fluid pressure into the piston chamber 99 of the feed jack 44 of each adjacent three prop unit 17. Since the three prop units 17 are jammed between the floor and the roof, their feed jacks 44 together exert a moderate advancing thrust on the conveyor which is reacted against by the natural resilience of the conveyor without permanent deformation. As each portion of the conveyor is thus advanced into proximity with the newly exposed coal face as at the position shown adjacent the three prop unit 17a, the operator may advance the three prop unit 17a singly to bring it into line with the already advanced two prop units.
  • Mine roof supporting apparatus for use in conjunction with coal cutting and conveying machinery which has a structure such as a conveyor framework extending along the coal face, said apparatus comprising a plurality of support units of first and second kinds disposed alternately along said structure, each unit having a roof bar extending transversely to said structure, means for adjusting the height of the roof bar, and a feed jack operatively interposed between said unit and said structure for effecting relative movement between them, said roof bars having forward cantilever extensions which are longer in the first kind of support unit than in the second kind, whereby said units of the first kind are capable of being advanced by their feed jacks relative to said structure to support the newly exposed roof in the wake of the coal cutter before said structure and said units of the second kind can be advanced.
  • Mine roof supporting apparatus for use in conjunction with coal cutting and conveying machinery which has a flexible conveyor framework extending along the coal face, said apparatus comprising a plurality of support units of first and second kinds disposed alternately and extending transverse to the coal face behind the conveyor framework, each support unit having a base member, a feed jack interposed between the base member and the conveyor framework for effecting relative movement between them, at least two extensible hydraulic props mounted on the base member, and a roof bar supported over its rearward length on the props so that the forward length constitutes a cantilever extension, the cantilever on each support unit of the second kind being of a length to support the mine roof over the conveyor when said unit is in proximity with the conveyor, and the cantilever on each support unit of the first kind being of greater length whereby each such unit may be advanced into proximity with the conveyor and in that position support the newly exposed roof in the Wake of the coal cutter.
  • Mine roof supporting apparatus for use in conjunc tion with coal cutting and conveying machinery which has a flexible conveyor framework extending along the and extending transverse to the coal face behind the.
  • each support unit having a base member, a feed jack interposed between the base member and the conveyor framework for effecting relative movementbetween them, at least two extensible hydraulic props supported by mountings respectively at the front and rear of the base member, and a roof bar, of the same length in the two kinds of support unit, comprising a rearward portion supported on the props and a forward portion constituting a cantilever which projects beyond the front of the base member, the base member and cantilever in units of the first kind being respectively shorter and longer than the base member and cantilever in units of the second .kind.
  • Mine roof supporting apparatus including interengaging means interconnecting the bottom end of each prop and the base member and between the top end of each prop and the roof bar, each such interengaging means locating one member to the other but being loose to permit angular movement between them, and resilient means disposed in the mounting for the base of each prop, said resilient means acting to restore the prop to the vertical with respect to the base member.
  • each base member comprises a hollow body with the feed jack disposed within its open forward portion, while the mounting for the front prop is fixed above the forward end of the hollow body.
  • mine roof supporting apparatus wherein the feed jack is a telescopic hydraulic jack having a cylinder mounted at its forward end in the forward part of the base member by a universal joint, and
  • a plurality of extensible support units of two kinds disposed alternately along the coal face in connective'asso ciation with an extended structure such as a conveyor, and each unit being constructed to provide support for the mine roof behind and over the structure by means: of a roof bar whose forward portion constitutes a canti-' lever, this cantilever being longer in the units of the first kind than in units of the second kind; the method com-,

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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)
  • Excavating Of Shafts Or Tunnels (AREA)
US566712A 1955-02-23 1956-02-20 Mine roof support systems Expired - Lifetime US2803444A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5450/55A GB823127A (en) 1955-02-23 1955-02-23 Improvements in and relating to mine roof support systems

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US2803444A true US2803444A (en) 1957-08-20

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US566712A Expired - Lifetime US2803444A (en) 1955-02-23 1956-02-20 Mine roof support systems

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US (1) US2803444A (enrdf_load_stackoverflow)
BE (1) BE545472A (enrdf_load_stackoverflow)
FR (1) FR1146211A (enrdf_load_stackoverflow)
GB (1) GB823127A (enrdf_load_stackoverflow)
NL (1) NL204785A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910282A (en) * 1957-07-15 1959-10-27 Dowty Mining Equipment Ltd Mine roof support devices
DE1182184B (de) * 1957-12-24 1964-11-26 Emil Weber Einrichtung zum schrittweisen Strebausbau
US3333426A (en) * 1964-04-11 1967-08-01 Gullick Ltd Self-advancing hydraulically extensible mine roof supports
US3856356A (en) * 1972-03-24 1974-12-24 Gullick Dobson Ltd Method of mining mineral
US4957327A (en) * 1988-07-20 1990-09-18 Klockner-Becorit Gmbh Methods of translating a face support
CN101787889A (zh) * 2010-03-18 2010-07-28 北京昊华能源股份有限公司 一种悬移支架综合机械化采煤方法
CN104453971A (zh) * 2014-12-09 2015-03-25 辽宁威跃集团机械制造有限公司 双组拆安设备
CN111255499A (zh) * 2020-03-17 2020-06-09 兖矿集团有限公司 滑顶移架用控制装置及相应的液压支架和滑顶移架方法

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1119803B (de) * 1958-09-13 1961-12-21 Rheinstahl Gmbh Wanheim Mechanisierter Strebausbau
DE1142569B (de) * 1959-10-09 1963-01-24 Gewerk Eisenhuette Westfalia Einrichtung zum Ruecken von Foerderern
DE1103268B (de) * 1959-10-31 1961-03-30 Bwg Bergwerks Und Walzwerk Mas Wandernder Stuetzrahmen fuer den Ausbau von Grubenraeumen
DE1198307B (de) * 1959-11-23 1965-08-12 Nuesse & Graefer Maschf Rueckverfahren zum Ruecken eines Ausbaus in Gestalt von Ausbaugestellen und eines Foerderers
DE1205036B (de) * 1960-06-30 1965-11-18 Kloeckner Werke Ag Wandernder Strebausbau mit Rahmen
DE1170354B (de) * 1960-07-13 1964-05-21 Rheinstahl Gmbh Wanheim Fuehrungsvorrichtung fuer maschinell rueckbare Ausbaurahmen
DE1408718B1 (de) * 1960-10-25 1972-12-14 Gewerk Eisenhuette Westfalia Rueckvorrichtung fuer wandernde Ausbauelemente
DE1199725B (de) * 1962-02-07 1965-09-02 Maschf Strebausbau, bestehend aus im Abstand nebeneinander aufgestellten rahmenartigen, hoehenverstellbaren Ausbaugestellen, die mittels Rueckzylinder vorziehbar sind
DE1280785B (de) * 1963-01-14 1968-10-24 Becorit Grubenausbau Gmbh Wanderpfeilerausbau fuer untertaegige Grubenbetriebe
DE1280183B (de) * 1964-11-17 1968-10-17 Dowty Mining Equipment Ltd Wandernder Strebausbau
CN103557024B (zh) * 2013-11-19 2015-11-11 辽宁鑫丰矿电设备制造有限公司 一种折叠式调向回撤平台

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE18491E (en) * 1932-06-14 Method oe and means fob supporting roof strata during the mining oe
US2657028A (en) * 1949-06-15 1953-10-27 Joy Mfg Co Walking jack

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE18491E (en) * 1932-06-14 Method oe and means fob supporting roof strata during the mining oe
US2657028A (en) * 1949-06-15 1953-10-27 Joy Mfg Co Walking jack

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910282A (en) * 1957-07-15 1959-10-27 Dowty Mining Equipment Ltd Mine roof support devices
DE1182184B (de) * 1957-12-24 1964-11-26 Emil Weber Einrichtung zum schrittweisen Strebausbau
US3333426A (en) * 1964-04-11 1967-08-01 Gullick Ltd Self-advancing hydraulically extensible mine roof supports
US3856356A (en) * 1972-03-24 1974-12-24 Gullick Dobson Ltd Method of mining mineral
US4957327A (en) * 1988-07-20 1990-09-18 Klockner-Becorit Gmbh Methods of translating a face support
CN101787889A (zh) * 2010-03-18 2010-07-28 北京昊华能源股份有限公司 一种悬移支架综合机械化采煤方法
CN104453971A (zh) * 2014-12-09 2015-03-25 辽宁威跃集团机械制造有限公司 双组拆安设备
CN111255499A (zh) * 2020-03-17 2020-06-09 兖矿集团有限公司 滑顶移架用控制装置及相应的液压支架和滑顶移架方法

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FR1146211A (fr) 1957-11-07
GB823127A (en) 1959-11-04
NL204785A (enrdf_load_stackoverflow) 1963-10-15
BE545472A (enrdf_load_stackoverflow)

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