US2857125A - Mine roof supports - Google Patents

Mine roof supports Download PDF

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Publication number
US2857125A
US2857125A US412303A US41230354A US2857125A US 2857125 A US2857125 A US 2857125A US 412303 A US412303 A US 412303A US 41230354 A US41230354 A US 41230354A US 2857125 A US2857125 A US 2857125A
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United States
Prior art keywords
pressure chamber
roof
prop
reservoir
liquid
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
US412303A
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English (en)
Inventor
Joseph A W Mills
Hugh L Holt
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 Hydraulic Units Ltd
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Dowty Hydraulic Units Ltd
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Filing date
Publication date
Application filed by Dowty Hydraulic Units Ltd filed Critical Dowty Hydraulic Units Ltd
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Publication of US2857125A publication Critical patent/US2857125A/en
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/44—Hydraulic, pneumatic, or hydraulic-pneumatic props
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/50—Component parts or details of props
    • E21D15/51—Component parts or details of props specially adapted to hydraulic, pneumatic, or hydraulic-pneumatic props, e.g. arrangements of relief valves
    • E21D15/517—Extension elements
    • 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
    • E21D23/04—Structural features of the supporting construction, e.g. linking members between adjacent frames or sets of props; Means for counteracting lateral sliding on inclined floor
    • E21D23/06—Special mine caps or special tops of pit-props for permitting step-by-step movement

Definitions

  • each prop is provided with a head-piece which engages the top of the prop and straddles the roof bar to have direct engagement with the roof at each side of the bar.
  • the bar is loaded into engagement with the roof by wedge members driven between the roof bar and the parts of the prop head-pieces directly below it.
  • the props still support the roof by direct engagement through the sides of their head-pieces. After each bar has been advanced and the wedges re-set, the rearmost prop of each row is released and erected at the front, so that the row of props is thereby advanced.
  • the head-pieces which straddle the roof bars form guides for the bars during their forward movements.
  • the present invention has for an object to provide improved props for use in a roof-supporting system of the general type referred to and in which two roof bars are employed with a single row of props, and according to this invention, a telescopic prop of the hydraulicallyactuated kind comprising a reservoir, a pressure chamber, pump means for transferring liquid under pressure from the reservoir into the chamber, and relief valve means in a return communication between the pressure chamber and reservoir, is provided with hydraulic thrust means adapted to engage and load a pair of roof bars disposed one at either side of the upper end of the prop, said hydraulic thrust means comprising a pressure chamber adapted to receive pressure liquid from the pump associated with the main pressure chamber of the prop, and to relieve into the prop reservoir independently of said main pressure chamber.
  • the pressure chamber of the hydraulic thrust means 2,857,125 Patented Oct. 21, 1958 may be in two parts constituted by two hydraulic jack devices for association with the two roof bars respectively.
  • a single pressure chamber which may be annular and surround the upper part of the prop, or which may be cylindrical and formed inside the upper part of the prop, may be arranged to load the two roof bars thr-e gh mechanical connection comprising two arms or equivalent members which are movable with the movable casing part of the pressure chamber.
  • the relief valve means associated with the main pressure chamber of the prop serves in known manner to limit chamber pressure automatically under increasing roof loading during use of the prop, and enables the pressure to be relieved at will under manual control.
  • the relief valve means associated with the pressure chamber of the hydraulic thrust means will likewise serve to limit the pressure in the chamber automatically, and to relieve the pressure in the chamber under manual control.
  • Figure 1 is a sectional side elevation of an arrangement wherein the pressure chamber of the hydraulic thrust means is cylindrical and situated inside the prop;
  • Figure 2 is a sectional view as seen on the line lIlI in Figure 1;
  • Figure 3 is a sectional view taken on the line III-Ill in Figure 1 and showing the relief valve means associated with the main pressure chamber of the prop;
  • Figure 4 is a sectional view taken on the line IV-IV in Figure 1, and showing the relief valve means associated with the pressure chamber of the hydraulic thrust means;
  • Figure 5 is a side elevation partly in section showing the upper end of a prop embodying a modified arrangement wherein the pressure chamber of the hydraulic thrust means is constituted by two hydraulic jack de vices, and
  • Figure 6 is a sectional side elevation showing the upper end of a prop embodying a further modified arrangement wherein the pressure chamber of the hydraulic thrust means is formed as a single annular chamber surrounding the prop.
  • the hydraulic prop comprises an upper tubular part indicated at 11 which has a head-piece 12 at its upper end and which is closed by a disc 13 at its lower end, and a lower tubular part 14 which is closed at its lower end by a foot piece 15 and which is sealed with respect to the upper part 11 by a high pressure sealing gland 16 carried by the disc 13.
  • the upper end of the tubular part 14 has a low pressure seal 17 engaging the outer surface of the tubular part 11 and serving to prevent dust and other foreign matter from passing down between the tubular parts 11 and 14.
  • the space inside the upper tubular part 11 forms a reservoir 18 for hydraulic liquid and accommodates a pump 1% the piston of which is adapted to be reciprocated from a rock shaft 20 to which a handle can be attached.
  • the pump 19 withdraws liquid from the reservoir 18 and delivers through an outlet passage 21 into the main pressure chamber 22 of the prop.
  • the upper tubular part 11. of the prop is raised until the top of the prop engages the mine roof and the requisite setting pressure has been created in the pressure chamber 22.
  • the tendency for the mine roof to sag increases the load on the prop and raises the pressure in the chamber 22.
  • a relief valve 23 blows to open a return communication extending between the said pressure chamber and the reservoir 18.
  • a conduit 24 which opens at its lower end into the pressure chamber 22 and which opens at its upper end into a bore 25 which is normally closed by the relief valve 23 but which, when the relief valve blows, communicates through a side port 26 with the reservoir 18.
  • the relief valve 23 can also be withdrawn from its seating when'relea'se of pressure in the chamber 22 is desired, as when the prop is to be withdrawn from service or shifted to a new position of support.
  • a loop 27 situated externally of the prop and which is connected with a stem 28 against a shoulder on which bears the relief valve spring 29.
  • the upper end of the tubular part 11 embodies hydraulic thrust means adapted to engage a pair of roof bars disposed one at either side of the prop and indicated at B and B in Figures 1 and 2.
  • a tubular extension 11a forming part of the upper tubular part 11 of the prop.
  • the inner cylindrical surface at the lower end of the tubular extension 11a forms the working cylindrical surface for a piston 30 which is sealed to the said surface by a sealing gland 31 secured to the piston.
  • the piston 30 carries a cross pin 32 which extends out at opposite sides of the prop through vertically extending slots 33 formed in'the tubular extension 11a, and the ends of which determine the limits of movement of the piston.
  • the pin 32 also extends through closely fitting holes in a thin sleeve 34 surrounding and slidably fitting the tubular extension 11a.
  • This sleeve 34 serves at all times to cover the otherwise exposed portions of the slots 33 and thus prevents dirt and other foreign matter from passing in through the slots 33.
  • the outer ends of the pin 32 are in pivotal connection with a roof-bar-engaging member 35 which comprises an oval-shaped tubular portion 36 and a pair of oppositely extending arms 37 which are suitably strengthened by webs 38.
  • the arms 37 present upper surfaces 39 for engagement with the underside of the roof bars B and B, and have upstanding end portions 40 which act as outward guides for said bars.
  • the space 43 inside the tubular extension 11a and situated below the piston 30 communicates with the outlet of the pump 19 through a tube 41.
  • the pump 19 when the pump 19 is operated, it not only delivers through the passage 21 into the main pressure chamber 22 of the prop but also delivers through a passage 42 and through the tube 41 into the pressure chamber 43, the top of which is constituted by the lower surface of the piston 30.
  • the piston 30 and with it the pin 32, sleeve 34 and roof-bar-engaging member 35 thus move up when the pump is operated. This upward movement continues until the arms 37 press the roof bars B and B against the mine roof and the requisite setting pressure is created in the pressure chamber 43.
  • the maximum pressure in the chamber 43 is determined by a relief valve 44 controlling a return communication extending between the tube 41 and the reservoir 18. Also, the valve 44 can be permitted to unseat by an outward and upward pull on a hand lever 45 which, by its connection with a stem 46, frees the valve from the etfect of its spring 47.
  • the ability of the roof-bar-engaging member 35 to pivot on the pin 32 ensures an equal distribution of the loads on the roof bars B and B.
  • a single hand pump therefore serves to supply pressure liquid into the main pressure chamber 22 to extend the prop into supporting engagement with themine roof, and also serves to supply pressure liquid into the chamber 43 to give the necessary loading to the roof bars B and B.
  • the pressures in the two chambers are not interdependent, and either chamber can be relieved and released independently of the other.
  • the pressure chamber of the hydraulic thrust means is formed in two parts constituted by two similar hydraulic jack devices and 51.
  • Each such device comprises a fixed lower cylindrical part 52 which carries at its upper end a piston 53 having a central opening 54.
  • the piston 53 has a high pressure sealing gland 55 which seals the fixed cylindrical part 52 with respect to'a movable upper cylindrical part 56 which is closed at its upper end by a head-piece 57 adapted to engage the undersurface of the corresponding roof bar.
  • the fixed cylindrical parts 52 of the jacks 50 and 51 are mounted on platforms 58 secured at the lower ends of U-shaped casings 59 which are welded along edges 60 to the upper tubular part 61 of the prop.
  • the pressure chambers within the jacks 50 and 51 communicate through conduits 62 and 63 respectively with the upper end of a conduit 64 which leads down to the outlet of the pump'of the prop.
  • the conduit 64 is thus the equivalent of the tube 41 of Figure 1.
  • the conduits 62, 63 and 64 also communicate' along a short conduit 65 with one side of a relief and release valve 66, the other side of which communicates through a conduit 67 with the reservoir of the prop.
  • the valve 66 may function automatically as a relief valve to limit pressure in the jacks, and may be releasable under manual control to relieve pressure in the jacks when desired.
  • the pump-actuating shaft is indicated at 68, and the manual control over the relief valve of the main pressure chamber of the prop' is indicated at 69.
  • the roof bars B and B are loosely guided during advancement thereof between a part of the corresponding casing 59 and an upstanding n'b 70 on the head-piece 57 of the corresponding jack.
  • the roof bars B and B are adapted to be loaded by hydraulic thrust means comprising a single pressure chamber 71 which is annular and surrounds the upper tube 72 of the prop.
  • the inner boundary of the pressure chamber 71 is thus formed by the tube 72, and the lower boundary by a flange 73 on said tube.
  • the outer boundary of the pressure chamber 71 is formed by a tube 75, and the upper boundary by a flange 76 on the tube 75. Below the flange 76 there is provided a further high pressure sealing gland 77.
  • the tube 75, flange 76, and sealing gland 77 are slidable up and down on the tube 72.
  • Pressure liquid is fed into the chamber 71 through a conduit 78 extending from the outlet of the pump of the prop.
  • the tube 78 has a branch 79 leading to a valve 80 which controls communication between the branch 79 and a side port 81 communicating with the reservoir of the prop.
  • the valve 80 operates automatically as a relief valve to limitthe pressure in the chamber 71, and a manual control is'provided whereby the pressure in the chamber 71 can be relieved at will.
  • the manual control comprises a screw plug 82 which can be turned through a squared boss 83 to withdraw the spring 84 and plunger 85 away from the valve 80.
  • a platform structure 86 of adequate strength is rigid with the tube 75 of the pressure chamber 71 and carries head-pieces 87 for engagement with the undersurfaces of the roof bars B and B. Short lengths of channel section metal 88 form loose guides for the bars during advancing movements of the latter.
  • the relief and release valve assembly of the main pressure chamber of the prop is indicated generally at 89, said valve communicating with said main pressure chamber through a pipe line 90.
  • the upper end of the prop which has direct engagement with the roof carries a short bar member capable of rocking movement relative to the prop. This distributes the load evenly over a suitable roof area.
  • a hydraulic pit prop for use in mines comprising inner and outer tubes closed at their outer ends and at ranged in overlapping slidable sealing relationship, the outer end of the inner tube being adapted for direct engagement with the mine roof, a transverse wall in the inner tube, said wall enclosing a space in the inner tube forming a liquid reservoir and, in conjunction with the outer tube, defining a main pressure chamber of variable volume, a pump mounted in the inner tube and arranged for transferring liquid from the reservoir into the main pressure chamber, first valve means interposed between the pressure chamber and the reservoir, said first valve means being operative, automatically, to relieve and, manually, to release pressure of the liquid in the main pressure chamber, auxiliary hydraulic jack means consisting of two relatively movable parts together forming an auxiliary pressure chamber, separate from the main pressure chamber, one of said parts being fixed to the outer end portion of the inner tube and the other of said parts being movable axially of the prop, two thrust arms mounted upon and extending to opposite sides of said other movable part, adapted to engage
  • a hydraulic pit prop for use in mines comprising inner and outer tubes closed at their outer ends and arranged in overlapping slidable sealing relationship, the outer end of the inner tube being adapted for direct engagement with the mine roof, a transverse wall in the inner tube, said wall enclosing .
  • a space in the inner tube forming a liquid reservoir and, in conjunction with the outer tube, defining a main pressure chamber of variable volume, a pump mounted in the inner tube and arranged for transferring liquid from the reservoir into the pressure chamber, first valve means interposed between the pressure chamber and the reservoir, said first Valve means being operative, automatically, to relieve and, manually, to release pressure of the liquid in the main pressure chamber, auxiliary' hydraulic jack means consisting of a cylinder formed by the outer end portion of the inner tube, a piston slidably fitting said cylinder and a transverse partition in the inner tube separating the jack cylinder from the liquid reservoir, a pin mounted transversely in said piston and projecting at opposite ends through longitudinally elongated slots formed in
  • a hydraulic pit prop for use in mines comprising inner and outer tubes closed at their outer ends and arranged in overlapping slidable sealing relationship, the outer end of the inner tube being adapted for direct engagement with the mine roof, a transverse wall in the inner tube, said wall enclosing a space in the inner tube forming a liquid reservoir and, in conjunction with the outer tube, defining a main pressure chamber of variable volume, a pump mounted in the inner tube and arranged for transferring liquid from the reservoir into the pressure chamber, first valve means interposed between the pressure chamber and the reservoir, said first valve means being operative, automatically, to relieve and, manually, to release pressure of the liquid in the main pressure chamber, two auxiliary hydraulic jacks secured one at each side to the inner tube at the outer end portion thereof and parallel thereto, the jacks being adapted to engage a pair of roof bars disposed one at either side of the outer closed end of the inner tube, a liquid passageway extending from the delivery side of said pump to the cylinder of each hydraulic jack, and second valve means interposed
  • a hydraulic pit prop for use in mines comprising inner and outer tubes closed at their outer ends and arranged in overlapping slidable sealing relationship, the outer end of the inner tube being adapted for direct en gagement with the mine roof, a transverse wall in the inner tube, said wall enclosing a space in the inner tube forming a liquid reservoir and, in conjunction with the outer tube, defining a main pressure chamber of variable volume, a pump mounted in the inner tube and arranged for transferring liquid from the reservoir into the pressure chamber, first valve means interposed between the pressure chamber and the reservoir, said first valve means being operative, automatically, to relieve and, manually, to release pressure of the liquid in the main pressure chamber, an annular auxiliary jack surrounding the inner tube at the outer end portion of the latter, said jack consisting of two relatively movable parts together forming an auxiliary pressure chamber, one of said parts being secured to said inner tube, and the other of said parts being movable axially of the prop, thrust means connect-ively associated with said other movable part, said thrust
  • a hydraulic pit prop of the character described comprising a floor-engaging tubular member and a roofengaging tubular member cooperating to define a vertically extensible mine roof support and an internal pressure chamber, and each formed at its outer end to provide a broad bearing area, the interior of one of said tubular members defining a hydraulic reservoir, pump means located within the mine roof support defined by said tubular members, and operatively interposed be tween said reservoir and said pressure chamber for delivering fluid from the reservoir under pressure into said pressure chamber to force said roof-engaging tubular member upwardly into supporting engagement with the roof, by reaction directly from said floor-engaging tubular member, a second roof-engaging member straddling said first-mentioned roof-engaging member and formed with two supporting arms at the respectively opposite sides of the latter, hydraulic piston and cylinder means carried the one by said roof-engaging tubular member and the other operatively connected to said two-armed roof-engaging member, to press the latter upwardly by reaction from the roof-engaging tubular member, conduit means connecting said pump with
  • a hydraulic pit'prop for use in mines comprising inner and outer tubes arrange in overlapping sli dable sealing relationship, one of sai tubsbeing adapted for direct'enga g'emen't' with" the roof, said inner tube having longitudinally spaced transverse partitionmeans enclosing a space 'in thel in'ne'rtube forming a liquid reservoii', said outer tube having transverse partition means defining' in conjunctioriwith the inner tube a main pressure chamber of a volume variable by relative axial move ment between the tubes first valve means int erposed between the pressure chamber and the reservoir, said first valve means being operative automatically to relieve and manually'torelease ressur dr the liquid in the main pressure chamber, pump means mounted in the inner tube 'and'arranged for transferring liquid from the reservoir iiito said main pressure chamber auxiliary hydraulic jack means consisting of two relatively movable parts together forming" an auxiliary pressure chamber separate from'said'main ress

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Architecture (AREA)
  • Actuator (AREA)
  • Press Drives And Press Lines (AREA)
US412303A 1953-02-25 1954-02-24 Mine roof supports Expired - Lifetime US2857125A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5311/53A GB741150A (en) 1953-02-25 1953-02-25 Improvements in mine roof supports

Publications (1)

Publication Number Publication Date
US2857125A true US2857125A (en) 1958-10-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
US412303A Expired - Lifetime US2857125A (en) 1953-02-25 1954-02-24 Mine roof supports

Country Status (6)

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US (1) US2857125A (de)
BE (1) BE526791A (de)
DE (1) DE946528C (de)
FR (1) FR1096391A (de)
GB (1) GB741150A (de)
NL (1) NL185384B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3830456A (en) * 1972-12-22 1974-08-20 Fletcher J & Co Mining apparatus
AT377058B (de) * 1981-05-12 1985-02-11 Alsace Mines Potasse Mechanische verbindung zwischen dem kopf oder dem fuss eines grubenstempels und der kappe oder der fussplatte eines ausbaubocks
CN102562100A (zh) * 2010-12-13 2012-07-11 襄樊禹仁机电液压科技有限公司 一种自动排气的单体液压支柱

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1094209B (de) * 1954-09-10 1960-12-08 Rheinstahl Gmbh Wanheim Grubenstempel
DE1023436B (de) * 1955-11-24 1958-01-30 Hermann Schwarz Kommanditgesel Hydraulischer Grubenstempel
BE553228A (de) * 1955-12-08
DE1062654B (de) * 1956-04-03 1959-08-06 Kloeckner Bergbau Viktor Icker Hydraulischer Grubenstempel
DE1081397B (de) * 1956-06-25 1960-05-12 Becorit Grubenausbau Gmbh Hydraulischer Grubenstempel
GB845918A (en) * 1957-02-06 1960-08-24 Dowty Mining Equipment Ltd Improvements in fluid pressure relief valves
GB894292A (en) * 1957-07-30 1962-04-18 Mastabar Mining Equip Co Ltd Improvements in or relating to hydraulic props, particularly pit props
GB948255A (en) * 1959-03-03 1964-01-29 Dobson Ltd W E & F Improvements in or relating to hydraulic pit props
FR1280684A (fr) * 1960-11-22 1962-01-08 Sagem étançon hydraulique

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE289904C (de) *
GB636568A (en) * 1953-07-20 1950-05-03 George Herbert Dowty Improvements in pit props and other telescopic struts
FR1009955A (fr) * 1948-07-15 1952-06-05 Soutènement de galerie de mine
US2641906A (en) * 1948-09-01 1953-06-16 Dowty Equipment Ltd Mine roof support

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE289904C (de) *
FR1009955A (fr) * 1948-07-15 1952-06-05 Soutènement de galerie de mine
US2641906A (en) * 1948-09-01 1953-06-16 Dowty Equipment Ltd Mine roof support
GB636568A (en) * 1953-07-20 1950-05-03 George Herbert Dowty Improvements in pit props and other telescopic struts

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3830456A (en) * 1972-12-22 1974-08-20 Fletcher J & Co Mining apparatus
AT377058B (de) * 1981-05-12 1985-02-11 Alsace Mines Potasse Mechanische verbindung zwischen dem kopf oder dem fuss eines grubenstempels und der kappe oder der fussplatte eines ausbaubocks
CN102562100A (zh) * 2010-12-13 2012-07-11 襄樊禹仁机电液压科技有限公司 一种自动排气的单体液压支柱

Also Published As

Publication number Publication date
BE526791A (de)
GB741150A (en) 1955-11-30
FR1096391A (fr) 1955-06-20
NL185384B (nl) 1958-04-15
DE946528C (de) 1956-08-02

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