US2621631A - Telescopic hydraulic mine roof support - Google Patents

Telescopic hydraulic mine roof support Download PDF

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Publication number
US2621631A
US2621631A US58949A US5894948A US2621631A US 2621631 A US2621631 A US 2621631A US 58949 A US58949 A US 58949A US 5894948 A US5894948 A US 5894948A US 2621631 A US2621631 A US 2621631A
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US
United States
Prior art keywords
prop
valve
ram
tube
handling member
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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
US58949A
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English (en)
Inventor
George H Dowty
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 Equipment Ltd
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Dowty Equipment Ltd
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Filing date
Publication date
Priority claimed from GB92548A external-priority patent/GB636568A/en
Application filed by Dowty Equipment Ltd filed Critical Dowty Equipment Ltd
Application granted granted Critical
Publication of US2621631A publication Critical patent/US2621631A/en
Anticipated expiration legal-status Critical
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
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/60—Devices for withdrawing props or chocks
    • 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
    • E21D15/45—Hydraulic, pneumatic, or hydraulic-pneumatic props having closed fluid system, e.g. with built-in pumps or accumulators

Definitions

  • This invention relates to hydraulically actuat- I ed telescopic struts intended primarily for use as props in shoring up ceiling sections in mines.
  • the invention is concerned with that type of strut or prop which comprises a ram, usually hollow to constitute a liquid reservoir, which acts as a plunger in an upright external cylinder which below the ram constitutes a pressure chamber, so that extension can be effected by pumping pressure fluid from the reservoir into the pressure chamber, and contraction can be effected by relieving or venting the pressure in such pressure chamber back to the reservoir by way of a valvecontrolled return duct. Contraction may occur automatically when the roof weight exceeds a predetermined weight, and whether or not contraction is automatic, it must occur under manual control when it is desired to dislodge and remove the prop.
  • contraction whether automatically or manually effected occurs by opening of a single valve, which is ordinarily biased to closed position but which is so connected to an external prop-handling member that a pull upon the latter from a safe distance will open the valve.
  • Continuation of the same pull acts, through a first lost-motion connection, to pull aside or drag away the prop.
  • a biasing force which may be the one which biases the valve to close, or a different one, serves to maintain the prop-handling member in a given relationship to the props casing and to the first lost-motion connection, such that that member must be pulled in a manner to open the valve and to bottom the lost-motion connection before it is effective to drag away the prop.
  • connection of thevalve to the prop-handling member is preferably arranged, through a second lost-motion connection, which not only supplements the action of the first lost-motion connection in allowing automatic opening of the valve for relief without corresponding movement of the prop-handling member from that given relationship, in the event pressure within the return duct exceeds a predetermined pressure, but has the further advantage that a blow on exterior valve-operating parts can not be transmitted to the valve itself, to damage or to jam it under the rough treatment to which it is necessarily subjected in use.
  • the condition of the prop or strut'at the time withdrawal is desired is generally such that the pressure of the actuating fluid acting on the valve and tending to unseat it will substantially balance the force acting on the valve by the control member and tending to seat it, the magnitude of the pull on the control member necessary to bring about contraction of the prop or strut is very small indeed.
  • control member in two parts with the second lost-motion connection between them whereby the relief valve and its seating are not subject to shocks caused by inward blows directed against the external part of the control member.
  • the external part of the control member associated with the valve is preferably enshrouded by a rigid shield extending out from the ram.
  • a prop or strut in accordance with the invention can very conveniently be removed from a position of support by attaching a cord or cable to the outer end of the control member and by pulling the cord or cable firstly to relieve the pressure in the chamber below the ram and secondly to cause the prop or strut to topple over about its lower end.
  • the operator can thus 'remove the prop orstrut while standing a safe distance away from the supported area, and he can remove the fallen prop or strut by dragging it endwise towards him. Its construction to these ends is a very important safety consideration in a pit prop.
  • Figure 1 is an axial sectional view of the upper end of the pit prop, and Figure 2 is a similar View of the lower end thereof, being in effect an axial continuation of Figure 1;
  • Figure 3 is a perspective view of the upper end of the prop, illustrating particularly the prophandling member
  • Figure 4 is a detail, in side elevation, and partly broken away, of the first lost-motion connecting means, between the prop-handling means and the casing.
  • the prop shown comprises a hollow tubular ram I which is closed at its upper end 2 and is slidable at its lower end telescopically within an outer cylinder 3 closed by a foot piece 4.
  • the lower end of the hollow ram I mounts a c1osure disc which is glanded at 6 to the inner surface of the cylinder 3.
  • the closure disc 5 is rigid with a co-axial tube I which extends for a short distance upwards into the ram to form the cylinder for the piston 8 of a reciprocating pump.
  • the piston 8 has a connecting rod 9 extending upwards through the ram to where it is pivotally connected to the pin II) of a crank II which can be oscillated between stops from the outside of the ram I by a detachable handle (not shown) engaging the square-section end of the crankshaft I2.
  • the piston 8 and the closure disc 5 have appropriate non-return valves I3 and I4 respectively whereby reciprocatidn of the piston 8 causes actuating fluid to be transferred from the interior of the ram I through the valve I I into the cylinder space below the ram I.
  • a generally tubular housing I5 for a relief valve for a relief valve.
  • the housing I5 has a transverse partition I6 situated within the ram, which partition I5 is formed with a co-axial passage II leading into a radial passage I8 which is in communication with the cylinder space below the ram I by means of a fixed tube I9 extending down from the partition I6 and through the closure disc 5 at th bottom end of the ram.
  • a ball valve co-operates with the seating formed by the passage I!
  • which in eifect is part of the valve, which is glanded at 22 to the inner surface of the housing I5 and is pressed against the ball 2!] by a spring 23 which bears at one end against the piston 2
  • is rigid with an apertured co-axial cup 25 having within the cup the head of a bolt 25 which extends out through the cup and is screwed into a control member 2'! which extends through the annular abutment 24 to the outside of the ram.
  • the control member 2'! and bolt 26 are in effect integral.
  • the thickness of the head of the bolt is less than the depth of the cup 25 so E that there is lost-motion connection (referred to above as the second lost-motion connection) between the control member 27 and the piston 2!.
  • a cross pin 28 extends through the control member 2'! and with clearance through holes 29 in the housing I5. This clearance is part of the first lost-motion connection, referred to above.
  • a handling loop 30 is attached to the ends of the cross pin 28, and ordinarily hangs downwardly therefrom.
  • the part of the housing I5 which is external of the ram I serves as a protection for the control member 2?. If, despite this precaution, the control member 21 should be subjected to any blows, the lost-motion will ensure that these will not be imparted to the ball valve 20.
  • of rubber or like material At the opposite end of the housin 25 there is provided an air valve 3
  • This valve 3% can be depressed from the outside against a spring 32 to permit air to pass into the upper part of the ram through three equally spaced passages of which one is shown in the drawingat 33.
  • the valve 3! is hollow and has a breather slit 3d through which air may escape from within the ram. The valve 3I thus ensures that the air pressure in the upper part of the ram will not depart substantially from atmospheric pressure.
  • the ram will be filled with hydraulic fluid to the level indicated at 35.
  • This level will be difierent for props of different lengths.
  • the filling operation can be achieved by unscrewing the end plug 33 and by tilting the prop so that the hydraulic fluid can be poured into th ram through two of the passages 33 whilst, air is escaping through the other passage 33.
  • the plug 33 with the air valve therein is replaced.
  • end closures 2 and Q at the upper and lower ends respectively of the prop extend in the radial sense to form flanges. These increase the areas of support, and if the prop should topple over, act to safeguard the tubes I and 3.
  • the housing I5 is first passed through diametrically opposite bores in the thickened upper part 4
  • the closure disc 5 with the tube I welded thereto is entered into the lower end of the tube I so that the tube I receives the piston 8 and the tube I9 is received in the corresponding bore in the disc 5.
  • the disc 5 can now be welded to the lower end of the tube I at 46, and the tube I9 welded to the disc 5.
  • the prop is completed by threading over the tube I the assembly comprising the tube 3, the foot piece 4 and the protecting tube 37.
  • the sleeve 38 is of course positioned around the upper end of the protecting tube 3! and the ring 39 for the gland 40 is welded to the upper end of the tube 3.
  • the pump When the prop is to support a ceiling section, the pump is operated to transfer actuating fluid from the reservoir within the hollow ram into the 'cylinderfspace below the ram. The prop will then extend and be clampedbetween the floor and ceiling. If the roof weight should exceed a predetermined weight due to the tendency for the roof to sag, the liquid acting on the relief valve 20, 2
  • is provided to permit air to pass into the upper end of the ram I when a considerable extension of the prop is being brought about by operation of the pump. There would otherwise be created in the ham a partial vacuum which would interfere with the proper operation of the pump. Also when the prop contracts a considerable amount the air in the upper part of the ram is correspondingly compressed and some of it may escape by forcing its way through the breather slit 34 in the valve.
  • jack casing formed of two relatively collapsible and extensible members defining an expansible-volume work chamber therebetween, a storage chamber in one of the members, said storage chamber containing and the work chamber being filled with a motive fluid during operation as a prop, admission duct and valve means between the chambers permitting flow of such fluid from the storage to the work chamber, a return duct between the chambers, means to apply pressure to the fluid to move the fluid from the storage to the Work chamber for extending said members, a prop-handling member adapted to receive a pull for dragging the prop, a reciprocable, lost-motion connecting means interconnecting said prop-handling member and said casing, holding means normally operable to hold said prop-handling member in a given relationship to said casing and yielda-ble by a pull on said prop-handling member to enable the latter and said lost-motion connecting means to move relative to said casing from said given relationship into positive pulling engagement with said casing with the
  • a jack casing formed of two relatively collapsible and extensible members defining an expansible-volume work chamber therebetween, a storage chamber in one of the members, said storage chamber containing and the work chamber being filled with a motive fluid during operation as a prop, admission duct and valve means between the chambers permitting flow of such fluid from the storage to the work chamber, a return duct between the chambers, means to apply pressure to the fluid to move thefiuid from the storage to the work chamber for extending said members, a valve located in and controlling communication through said return duct, holding means retaining said valve normally in closed position, whereby to maintain the prop extended in load-bearing condition, a prop handling member adapted to receive a pull for dragging the prop, said holding means being operatively connected to said prop handling member to retain the latter in a given relationship to said casing means, but being yieldable by a pull on said prophandling member, initially to enable opening of said valve
  • a hydraulic pit prop as in claim 4 including a bolt interconnecting the valve and the prophandling member for positive movement of said member to its given relationshi upon movement of the valve to closed position, a spring urging the valve into closed position and constituting the holding means, a second lost-motion means interconnecting the bolt and one or the other of the prop-handling member and the valve, for opening of the valve in opposition to said spring for relief of duct pressure in excess of a predetermined value, independently of movement of said prop-handling member.
  • a hydraulic pit prop as in claim 4 including an elongated valve housing directed transversely of and secured rigidly to the casing adjacent its upper end, the return duct including said valve housing, and the valve being guided in and for opening and closing movement lengthwise of said housing, means including a bolt interconnecting the prop-handling member and the valve, through the housing, a spring constituting the holding means and reacting between the valve housing and the valve to hold the latter yieldably closed, and through said bolt urging the prop-handling member into its given relationship to the casing, said prop-handling member being arranged for operative movement from such given relationship by a pull in a direction generally transverse to the casing.
  • a hydraulic pit prop as in claim 4 including an elongated valve housing directed transversely of and secured rigidly to the casing adjacent its upper end, the return duct including said valve housing, and the valve being guided in and for opening and closing movement lengthwise of said housing, means including a bolt interconnecting the prop-handling member and the valve and directing lengthwise of the valve housing, a spring constituting the holding means, disposed within the casing and urging the valve into closed position, and through said bolt urging the prop-handling member into its given relationship to the casing, and the prop-handling member being formed as a handle loop pivotally hung from said bolt, externally of the casing, for pulling engagement from a distant point to release the valve and to drag away the prop.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Safety Valves (AREA)
  • Control Of Presses (AREA)
US58949A 1948-01-12 1948-11-08 Telescopic hydraulic mine roof support Expired - Lifetime US2621631A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB92548A GB636568A (en) 1953-07-20 1948-01-12 Improvements in pit props and other telescopic struts
GB2011253A GB726384A (en) 1953-07-20 1953-07-20 Improvements in pit props and other telescopic struts

Publications (1)

Publication Number Publication Date
US2621631A true US2621631A (en) 1952-12-16

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Family Applications (1)

Application Number Title Priority Date Filing Date
US58949A Expired - Lifetime US2621631A (en) 1948-01-12 1948-11-08 Telescopic hydraulic mine roof support

Country Status (5)

Country Link
US (1) US2621631A (en(2012))
BE (1) BE486663A (en(2012))
DE (1) DE808225C (en(2012))
FR (2) FR978701A (en(2012))
NL (1) NL76043C (en(2012))

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2713773A (en) * 1953-09-24 1955-07-26 Dowty Auto Units Ltd Hydraulic pit prop or jack
US2888231A (en) * 1952-05-27 1959-05-26 Mining Engineering Co Ltd Roof supports
US2888230A (en) * 1952-06-16 1959-05-26 Mining Engineering Co Ltd Roof supports
US2895454A (en) * 1955-06-10 1959-07-21 Mastabar Mining Equip Co Ltd Props, especially for use in coal mines
US2899976A (en) * 1959-08-18 Release relief valve
US2981199A (en) * 1956-06-28 1961-04-25 Becorit Grubenausbau Gmbh Fluid pumps
US2985418A (en) * 1958-10-29 1961-05-23 Mastabar Mining Equip Co Ltd Extensible hydraulic supports
US2996888A (en) * 1959-01-26 1961-08-22 Raymond Int Inc Hydraulic pile puller
US3000358A (en) * 1959-02-23 1961-09-19 Dowty Mining Equipment Ltd Hydraulic props or struts
US3001808A (en) * 1957-01-31 1961-09-26 Dowty Mining Equipment Ltd Telescopic tubular pit props
US3012404A (en) * 1955-12-13 1961-12-12 Rheinstahl Wanheim Gmbh Hydraulic support
US3134398A (en) * 1960-06-17 1964-05-26 Acrow Eng Ltd Hydraulic prop valve
US3142156A (en) * 1960-12-22 1964-07-28 Dowty Mining Equipment Ltd Telescopic hydraulic props
US3321372A (en) * 1964-01-17 1967-05-23 Soc Anglo Belge Vulcain Sa Nuclear reactor control mechanism
US4237769A (en) * 1978-04-03 1980-12-09 Commercial Shearing, Inc. Relief valves and mine props incorporating the same
US4252476A (en) * 1978-09-12 1981-02-24 Bochumer Eisenhutte Heintzmann Gmbh & Co. Hydraulically operated mine prop with safety valve
US5051039A (en) * 1988-07-04 1991-09-24 Heiliger Martha Catharina Hydraulic steel mine prop
US5205676A (en) * 1990-05-11 1993-04-27 Heiliger Robert W Hydraulic steel mine prop
US5297901A (en) * 1991-12-06 1994-03-29 Grubenausbau Gmbh Individual hydraulic prop with filling/drawing valve and pressure fluid return
US5611646A (en) * 1993-07-14 1997-03-18 Richard Voss Grubenausbau Gmbh Support prop with integrated pressure limiting valve and nailed pipes
US5720581A (en) * 1993-05-07 1998-02-24 Dorbyl Limited Support prop
US20120148350A1 (en) * 2010-12-10 2012-06-14 Kenneth Poulson Mine prop jack and method of prestressing a mine prop
US10352167B2 (en) * 2016-11-03 2019-07-16 China University Of Mining And Technology Process method for withdrawing and recovering mechanical constant-resistance single prop

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1072941B (de) * 1960-01-14 -Ing H Joe Rheinbay Marienheide Dipl (RhId) Hydraulisch betätigter mit einem durch Atmosphären- oder Preßluftdruck beauf schlagten Schwimmkolben ausgerüsteter Grubenstempel
GB700790A (en) * 1951-07-19 1953-12-09 Dowty Auto Units Ltd Improvements relating to valves
GB746862A (en) * 1953-09-04 1956-03-21 Dowty Hydraulic Units Ltd Improvements in hydraulic pit props
GB767012A (en) * 1953-11-12 1957-01-30 Coal Industry Patents Ltd Improvements in or relating to pit or like props
DE1131625B (de) * 1955-08-13 1962-06-20 Kronprinz Ag Hydraulischer Grubenstempel
DE1062654B (de) * 1956-04-03 1959-08-06 Kloeckner Bergbau Viktor Icker Hydraulischer Grubenstempel
DE1108157B (de) * 1957-02-11 1961-06-08 Hermann Schwarz K G Druckmittelraum fuer Elemente des Grubenausbaus
GB894292A (en) * 1957-07-30 1962-04-18 Mastabar Mining Equip Co Ltd Improvements in or relating to hydraulic props, particularly pit props
DE1061273B (de) * 1958-01-13 1959-07-16 Kloeckner Bergbau Victor Icker Hydraulischer Grubenstempel
NL233516A (en(2012)) * 1958-11-24 1965-06-25
GB962542A (en) * 1959-08-21 1964-07-01 Acrow Eng Ltd Improvements in and relating to hydraulic props
DE1137406B (de) * 1960-06-30 1962-10-04 Kronprinz Ag Hydraulischer Grubenstempel
FR1280684A (fr) * 1960-11-22 1962-01-08 Sagem étançon hydraulique
DE1215635B (de) * 1963-11-29 1966-05-05 Rheinstahl Gmbh Wanheim Reibungsstempel mit hydraulischer Setz- und Spannvorrichtung
DE2603978C3 (de) * 1976-02-03 1982-10-14 Thyssen Industrie Ag, 4300 Essen Gebirgsschlagventilanordnung in einem hydraulischen Grubenstempel

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US151670A (en) * 1874-06-02 Improvement in hydraulic lifting-jacks
US1133270A (en) * 1913-05-03 1915-03-30 Charles E Dale Pump appliance.
US1598426A (en) * 1925-07-03 1926-08-31 Ingersoll Rand Co Shank and bit punch
US1706309A (en) * 1927-02-04 1929-03-19 May Sumner Hydraulic and other fluid pressure lifting jack
US1805588A (en) * 1926-01-05 1931-05-19 Manley Mfg Company Hydraulic jack
US2284228A (en) * 1940-03-18 1942-05-26 Herbert E Page Pressure multiplying mechanism

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US151670A (en) * 1874-06-02 Improvement in hydraulic lifting-jacks
US1133270A (en) * 1913-05-03 1915-03-30 Charles E Dale Pump appliance.
US1598426A (en) * 1925-07-03 1926-08-31 Ingersoll Rand Co Shank and bit punch
US1805588A (en) * 1926-01-05 1931-05-19 Manley Mfg Company Hydraulic jack
US1706309A (en) * 1927-02-04 1929-03-19 May Sumner Hydraulic and other fluid pressure lifting jack
US2284228A (en) * 1940-03-18 1942-05-26 Herbert E Page Pressure multiplying mechanism

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899976A (en) * 1959-08-18 Release relief valve
US2888231A (en) * 1952-05-27 1959-05-26 Mining Engineering Co Ltd Roof supports
US2888230A (en) * 1952-06-16 1959-05-26 Mining Engineering Co Ltd Roof supports
US2713773A (en) * 1953-09-24 1955-07-26 Dowty Auto Units Ltd Hydraulic pit prop or jack
US2895454A (en) * 1955-06-10 1959-07-21 Mastabar Mining Equip Co Ltd Props, especially for use in coal mines
US3012404A (en) * 1955-12-13 1961-12-12 Rheinstahl Wanheim Gmbh Hydraulic support
US2981199A (en) * 1956-06-28 1961-04-25 Becorit Grubenausbau Gmbh Fluid pumps
US3001808A (en) * 1957-01-31 1961-09-26 Dowty Mining Equipment Ltd Telescopic tubular pit props
US2985418A (en) * 1958-10-29 1961-05-23 Mastabar Mining Equip Co Ltd Extensible hydraulic supports
US2996888A (en) * 1959-01-26 1961-08-22 Raymond Int Inc Hydraulic pile puller
US3000358A (en) * 1959-02-23 1961-09-19 Dowty Mining Equipment Ltd Hydraulic props or struts
US3134398A (en) * 1960-06-17 1964-05-26 Acrow Eng Ltd Hydraulic prop valve
US3142156A (en) * 1960-12-22 1964-07-28 Dowty Mining Equipment Ltd Telescopic hydraulic props
US3321372A (en) * 1964-01-17 1967-05-23 Soc Anglo Belge Vulcain Sa Nuclear reactor control mechanism
US4237769A (en) * 1978-04-03 1980-12-09 Commercial Shearing, Inc. Relief valves and mine props incorporating the same
US4252476A (en) * 1978-09-12 1981-02-24 Bochumer Eisenhutte Heintzmann Gmbh & Co. Hydraulically operated mine prop with safety valve
US5051039A (en) * 1988-07-04 1991-09-24 Heiliger Martha Catharina Hydraulic steel mine prop
US5205676A (en) * 1990-05-11 1993-04-27 Heiliger Robert W Hydraulic steel mine prop
US5297901A (en) * 1991-12-06 1994-03-29 Grubenausbau Gmbh Individual hydraulic prop with filling/drawing valve and pressure fluid return
US5720581A (en) * 1993-05-07 1998-02-24 Dorbyl Limited Support prop
US5611646A (en) * 1993-07-14 1997-03-18 Richard Voss Grubenausbau Gmbh Support prop with integrated pressure limiting valve and nailed pipes
US20120148350A1 (en) * 2010-12-10 2012-06-14 Kenneth Poulson Mine prop jack and method of prestressing a mine prop
US10352167B2 (en) * 2016-11-03 2019-07-16 China University Of Mining And Technology Process method for withdrawing and recovering mechanical constant-resistance single prop

Also Published As

Publication number Publication date
FR69104E (fr) 1958-10-01
NL76043C (en(2012)) 1954-05-15
DE808225C (de) 1951-07-12
BE486663A (en(2012))
FR978701A (fr) 1951-04-17

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