US3240021A - Mine roof supporting structure - Google Patents

Mine roof supporting structure Download PDF

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Publication number
US3240021A
US3240021A US211344A US21134462A US3240021A US 3240021 A US3240021 A US 3240021A US 211344 A US211344 A US 211344A US 21134462 A US21134462 A US 21134462A US 3240021 A US3240021 A US 3240021A
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US
United States
Prior art keywords
extension
roof
extension member
recess
extensions
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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
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US211344A
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English (en)
Inventor
Meriaux Michel
Lablache-Combier Michel
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.)
MINES DOMANLALES DE POTASSE D
MINES DOMANLALES DE POTASSE D'ALSACE
Original Assignee
MINES DOMANLALES DE POTASSE D
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.)
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Application filed by MINES DOMANLALES DE POTASSE D filed Critical MINES DOMANLALES DE POTASSE D
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Publication of US3240021A publication Critical patent/US3240021A/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
    • E21D17/00—Caps for supporting mine roofs
    • E21D17/02—Cantilever extension or similar protecting devices
    • E21D17/08—Cap joints for obtaining a coal-face free of pit-props
    • E21D17/082—Cap joints for obtaining a coal-face free of pit-props of sliding type
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D17/00—Caps for supporting mine roofs
    • E21D17/02—Cantilever extension or similar protecting devices
    • E21D17/0206—Hydraulically operated extension devices
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D17/00—Caps for supporting mine roofs
    • E21D17/02—Cantilever extension or similar protecting devices
    • E21D17/08—Cap joints for obtaining a coal-face free of pit-props
    • 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
    • E21D23/063—Retractable cantilever extensions therefor

Definitions

  • movable supporting elements in present day embodiments are very often equipped with extensions of different types, intended to support the roof above the working passage; these extensions are usually clamped against the roof by a mechanical system; sometimes they are of the hydraulic-lift type.
  • a mine roof supporting structure comprises an extension which is adapted to be slidably mounted in a recess in a roof supporting member for movement between a retracted position and an extended position in which it projects forwardly from the said member, and a hydraulic clamping device which is operative to force the extension, in its extended position, against a mine roof.
  • a second extension is provided which is housed in the first extension, and is movable between a retracted position and an extended position, and can be clamped in its extended position between the first extension and the mine roof.
  • Such a structure can be so arranged that, when the said extensions are fully extended, they can immediately sup port the roof which is uncovered after the cutting machine has passed; in addition, the extensions may be capable of being fully retracted into the cover of the main supporting element should the roof subside or also should the cutting machines be particularly bulky, and this possibility enables the working passage to be completely cleared for the said machines to pass. Moreover,
  • extension system may be retracted at the last moment, that is to say even if the front part of the cutting machine is already engaged under the said extensions; in addition to this great flexibility in use conferred on it by its mechanical design, this system of extensions is designed to be hydraulically clamped against the roof, that is to say it exhibits all the advantages of the hydraulic supporting system.
  • FIGURE 1 is a sectional elevation of a supporting structure in accordance. Wtih the invention.
  • FIGURE 2 is a part-sectioned elevation, similar to FIGURE 1, showing some parts in different relative positions;
  • FIGURE 3 is an elevation similar to FIGURE 1, showing parts in other different relative positions;
  • FIGURE 4 is an elevation of a variant of embodiment.
  • the supporting structure comprises a first extension l which can retract fully into the cover 2 of a main roof supporting element, and a second extension 3 which can be fully retracted into the extension 1.
  • the second extension 3 need not be provided unless there is a large degree of overhang to be supported; if less protection is suflicient, the structure need comprise only the single extension l.
  • the first extension it consists of a steel box-girder element, of a profile which enables heavy stresses to be withstood, while leaving the internal space la required for the second extension 3 to be able to be fully accommodated therein.
  • the first extension ll At its forward end, the first extension ll comprises bearing portion 1b which is forced against the roof when clamping takes place, and, if required lugs (not illustrated), intended to facilitate extending and retracting movements of the said extension.
  • the extension 1 is formed with a stroke-limiting abutment 1c which can cooperate with a cross-member 2a mounted in the cover 2 in order to prevent the extension from emerging from the said cover when not required to do so.
  • this abutment may be used to guide the extension 1 inside the recess 2b in the cover 2.
  • the extension 1 In its lower face, the extension 1 has a spherical cavity 1d intended to receive the head 4a of a hydraulic jack 4 which will be described later.
  • the extension comes to bear under the action of the jack 4 against the abutment 1c and against the head 4:: of the jack, while the bearing portion 1b comes into contact with the roof 5 of the working passage (see FIGURE 2).
  • the stroke of the stern of the jack 4 and the dimensions of the extension 1 are so calculated that this contact can be made with large amounts of inclination between the extension and the cover 2: for example, angles of 7 to 8 may easily be obtained for extension lengths of 800 to 1000 mm.
  • the aperture in the cover 2 may also be made of flared shape in order to give increased possibilities of clearance to the extension l, and to enable the system of extensions to be adapted to very undulating roofs (see positions A, B, C, FIGURE 2).
  • the second extension 3 is intended to lengthen the extension 1 up to the face of the workings in order to support the new roof uncovered by the cutting machine, just after the latter has passed.
  • the latter may be a single strip of spring steel, or ordinary steel, according to the roofs encountered. If circumstances require, it may also be a profiled member of any shape.
  • This secnd extension 3 retracts fully into the internal space 1a of the extension 1; it is furthermore fitted with a strokelimiting abutment 3a which can cooperate with a shoulder 16 on the upper wall of the recess 1a in order to prevent the extension 3 from emerging completely from its recess.
  • this extension 3 may be clamped against the roof, without any need to touch the extension 1, by virtue of an auxiliary clamping system using a wedge 6.
  • This clamping device enables the extension 3 to be correctly clamped against the roof 5, even if the latter comprises undulations or irregularities (see FIGURE 3).
  • the hydraulic clamping device is intended on the one hand to clamp the whole telescopic unit against the roof, and on the other hand to control lowering of the roof by offering a definite resistance. It takes the form of a hydraulic jack mounted on a bracket 7 fast with the cover 2 of the supporting element.
  • the jack 4 may be a single-acting hydraulic jack, the weight of the extensions as a whole being quite sufficient to force the ram into the cylinder when the jack is re lieved of pressure. Its stroke must be sutficient to give clearance for the higher extensions (positions A, B, C, FIGURE 2), and the force which it develops is clearly a function of the loads which it is desired to support at the end of the extensions 1 and 3, and must consequently be adapted to the resistance to bending exhibited by the said extensions. For example, for the loads envisaged above on the extensions 1 and 3, a force of 8 to 9 tons for the jack 4 is very suitable.
  • the jack may be fed by a single conduit which gives both feed and return, inlet (when the feed pump is running) or exhaust (when the pump is stopped) being via the same Valve (needle-tap, poppet valve or any other similar device).
  • a safety valve for relieving the pressure in the jack whereby to allow the jack to telescope under a predetermined mine roof pressure.
  • the pressure required for clamping purposes must be very close to the pressure at which the valve will open in order to limit as far as possible the effects due to elastic deforma tion of the extensions. For example, if clamping is to take place at 200 kg./cm. the safety valve may be set for a pressure of 250 kg./cm.
  • the safety valve may be mounted on the jack unit itself, and may exhaust to atmosphere. In view of the small cross-section of the jack, the volume of liquid to be discharged if sliding occurs will remain practically negligible.
  • the auxiliary clamping device 6 enables the extension 3 to be locked or unlocked independently of the extension 1.
  • This device is a simple wedge which can be attached by a small chain to the end of the extension 1.
  • this wedge is inserted and clamped under the extension 3 at the entrance to the recess 1a; the extension 3 is then forced against the roof 5, and bears against the stroke-limiting abutment 3a and the wedge 6.
  • the system of extensions is furthermore so calculated that if a load is applied at any point on one of the extensions 1 or 3 when they are fully extended the jack 4 will collapse before the elastic limit of one of the said extensions is reached.
  • the lengths of the two extensions 1 and 3, their profiles, their mechanical resistances, and the force developed by the jack 4 and its stroke are clearly a function of the local conditions of the roof, the width of the working passage, and the depth of cut of the cutting machine.
  • each of the extensions 1, 3 may be clamped against the roof in any position intermediate its retracted and fully extended positions, which clearly gives the system very great flexibility in use by allowing the bearing portion of the extension 1 or of the extension 3 to be placed at a carefully chosen point. For example it may be desired to support a particular portion of the roof which is cracked or fractured or is otherwise of doubtful strength. Similarly, if the working passage is abnormally contracted one or other of the two extensions, or both, may be used partially or fully extended.
  • the first extension 1 (FIGURE 2) is fully extended from the cover 2 of the main supporting element; the extension 1 is clamped against the roof 5 by the jack 4; with the second extension 3 normally in its retracted position in the extension 1, the wedge 6 being simply lodged under the extension 3 at the entrance to the recess 1a. If roof conditions are difiicult, the extension 3 may be extended from the extension 1 as far as the face of the workings, thus giving protection to the whole working passage.
  • the extensions 1 is retracted into the cover 2 at the last moment.
  • the jack 4 is exhausted and the extension 1 is freed and can thus be retracted into the cover 2, the extension 3 still remaining inside the extension 1.
  • This operaion may be carried out in all cases at the very last moment, even if the front part of the machine is already engaged under the extension, and this is a considerable advantage with respect to known pivoting or demountahle extensions, the removal of which involves insoluble problems once the machine is engaged.
  • the extension 3 which is much less thick than the extension 1, may in certain cases be extended and re-clamped against the roof; this additional protection may be advantageous with very difficult roofs.
  • the jack 4- is unclamped, the extension 1 is brought fully extended from the cover 2 again, the extension 3 is extracted from the extension 1, the wedge 6 is placed in position, and the whole is re-clamped against the roof by the jack 4; as in the foregoing case, the roof which has been uncovered is supported immediately the machine has passed.
  • the jack 4' instead of being mounted on a bracket fast with the cover 2, is fixed at the end of the first extension 1, and moves in unit with the said extension.
  • This jack may be fed by a flexible pipe 472 which is fitted inside the cover 2 in order not to hinder movement of the system of extensions.
  • a bearing plate is pivoted at the entrance of the recess 2b.
  • the jack 4' acts vertically upwardly on the upper wall of the recess 2b to bring the extension 1 to bear both against the piece 20 and the head 4a of the said jack.
  • This system of extensions is used in the same way as the system of extensions described above.
  • the structure primarily is intended for incorporation in any hydraulic supporting system, in particular a moving supporting system; however, it may be adapted to any kind of supporting system comprising a cover which will enable the extension 1 to be accommodated in the retracted position.
  • the structure described above gives virtually complete safety in working faces in return for very simple operations. Its flexibility and convenience in use are its essential qualities: it makes it possble to uncover only the very minimum required for the cutting machine to pass, which is an indispensable condition in the case of poor roofs.
  • a mine roof supporting structure comprising a mine roof supporting member having a hollow interior defining a recess, an extension member slidably disposed in said recess in a telescoping arrangement, said extension member being movable from a retracted position in the recess to an extended position relative to the recess, one end of said extension member remaining Within said recess, a bearing member positioned within said recess adjacent one end of said supporting member, said bearing member adapted to engage said extension member intermediate the ends thereof to thereby provide a fulcrum for the extension member when at the extended position, hydraulic clamping means secured to said extension member in proximity to said one end thereof, said hydraulic clamping means being carried as a.
  • said hydraulic clamping means including a hydraulic jack having a ram element, said ram element being movable into engagement with the interior of said supporting member, whereby said extension member is pivoted about the bearing member such that said one end of said extension member moves in one direction and the opposite end of said extension member is moved in the opposite direction and forced against a mine roof.
  • wedging means is operatively disposed between said extension member and said second extension member.

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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)
  • Architecture (AREA)
  • Structural Engineering (AREA)
  • Safety Valves (AREA)
  • Lining And Supports For Tunnels (AREA)
US211344A 1961-07-22 1962-07-20 Mine roof supporting structure Expired - Lifetime US3240021A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR868738A FR1303511A (fr) 1961-07-22 1961-07-22 Système de rallonges télescopiques à portance hydraulique pour éléments de soutènement en taille

Publications (1)

Publication Number Publication Date
US3240021A true US3240021A (en) 1966-03-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
US211344A Expired - Lifetime US3240021A (en) 1961-07-22 1962-07-20 Mine roof supporting structure

Country Status (6)

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US (1) US3240021A (fr)
BE (1) BE618721A (fr)
FR (1) FR1303511A (fr)
GB (1) GB981568A (fr)
LU (1) LU41944A1 (fr)
OA (1) OA00401A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3352081A (en) * 1963-09-09 1967-11-14 Hunnebeck Ag Extensible girder construction and clamping means therefor
US3365893A (en) * 1964-02-12 1968-01-30 Gullick Ltd Mine roof supports
US3425229A (en) * 1962-11-10 1969-02-04 Karl Maria Groetschel Mine roof support
US4048803A (en) * 1973-12-07 1977-09-20 Banyaszati Kutato Intezet Mining shield support apparatus
US4124984A (en) * 1976-09-24 1978-11-14 Huwood Limited Mine roof supports
DE3221486A1 (de) * 1982-06-07 1983-12-08 Gewerkschaft Eisenhütte Westfalia, 4670 Lünen Vorpfaendeinrichtung fuer hydraulische schreitausbaugestelle
US4480946A (en) * 1981-10-19 1984-11-06 Kelley Jay H Gob canopy for a mine roof support
US4483644A (en) * 1982-09-15 1984-11-20 Johnson Thomas P Cantilevered mobile marine rig with hydraulic load equalizer
US4492495A (en) * 1982-07-09 1985-01-08 Dowty Mining Equipment Limited Roof support for use in mines
US4565263A (en) * 1985-06-10 1986-01-21 Southworth Ted J Sawhorse with extendible and contractible leg assemblies
CN102305090A (zh) * 2011-09-29 2012-01-04 郑州四维机电设备制造有限公司 伸缩梁机构

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2196371B (en) * 1986-10-15 1990-05-09 Gullick Dobson Ltd Mine roof supports

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1192849A (fr) * 1957-04-20 1959-10-28 Hoesch Werke Ag Allonge de soutènement
GB823586A (en) * 1956-06-05 1959-11-11 Hoesch Westfalenhutte Ag Improvements in or relating to mine roof supports
DE1077618B (de) * 1959-04-16 1960-03-17 Hermann Schwarz Kommanditgesel Nachgiebige Streckenstuetze
FR1245142A (fr) * 1959-01-16 1960-11-04 Gullick Ltd Dispositifs à vérin hydraulique particulièrement applicables aux soutènements detoit de mine
US3127748A (en) * 1960-05-10 1964-04-07 Gullick Ltd Mine roof supports

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB823586A (en) * 1956-06-05 1959-11-11 Hoesch Westfalenhutte Ag Improvements in or relating to mine roof supports
FR1192849A (fr) * 1957-04-20 1959-10-28 Hoesch Werke Ag Allonge de soutènement
FR1245142A (fr) * 1959-01-16 1960-11-04 Gullick Ltd Dispositifs à vérin hydraulique particulièrement applicables aux soutènements detoit de mine
DE1077618B (de) * 1959-04-16 1960-03-17 Hermann Schwarz Kommanditgesel Nachgiebige Streckenstuetze
US3127748A (en) * 1960-05-10 1964-04-07 Gullick Ltd Mine roof supports

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3425229A (en) * 1962-11-10 1969-02-04 Karl Maria Groetschel Mine roof support
US3352081A (en) * 1963-09-09 1967-11-14 Hunnebeck Ag Extensible girder construction and clamping means therefor
US3365893A (en) * 1964-02-12 1968-01-30 Gullick Ltd Mine roof supports
US4048803A (en) * 1973-12-07 1977-09-20 Banyaszati Kutato Intezet Mining shield support apparatus
US4124984A (en) * 1976-09-24 1978-11-14 Huwood Limited Mine roof supports
US4480946A (en) * 1981-10-19 1984-11-06 Kelley Jay H Gob canopy for a mine roof support
DE3221486A1 (de) * 1982-06-07 1983-12-08 Gewerkschaft Eisenhütte Westfalia, 4670 Lünen Vorpfaendeinrichtung fuer hydraulische schreitausbaugestelle
US4492495A (en) * 1982-07-09 1985-01-08 Dowty Mining Equipment Limited Roof support for use in mines
US4483644A (en) * 1982-09-15 1984-11-20 Johnson Thomas P Cantilevered mobile marine rig with hydraulic load equalizer
US4565263A (en) * 1985-06-10 1986-01-21 Southworth Ted J Sawhorse with extendible and contractible leg assemblies
CN102305090A (zh) * 2011-09-29 2012-01-04 郑州四维机电设备制造有限公司 伸缩梁机构

Also Published As

Publication number Publication date
OA00401A (fr) 1966-05-15
FR1303511A (fr) 1962-09-14
BE618721A (fr) 1962-10-01
GB981568A (en) 1965-01-27
LU41944A1 (fr) 1962-08-27

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