US20140072374A1 - Support prop - Google Patents
Support prop Download PDFInfo
- Publication number
- US20140072374A1 US20140072374A1 US13/651,926 US201213651926A US2014072374A1 US 20140072374 A1 US20140072374 A1 US 20140072374A1 US 201213651926 A US201213651926 A US 201213651926A US 2014072374 A1 US2014072374 A1 US 2014072374A1
- Authority
- US
- United States
- Prior art keywords
- tubular member
- volume
- closure
- wedge
- support prop
- 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.)
- Abandoned
Links
- 239000007788 liquid Substances 0.000 claims abstract description 9
- 238000009412 basement excavation Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Images
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
- E21D15/50—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
- E21D15/512—Arrangement of valves
-
- 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
- E21D15/28—Telescopic props with parts held relatively to each other by friction or gripping
- E21D15/43—Details of wedges
-
- 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
Definitions
- This invention relates to a support prop suitable for use in an underground excavation, for providing support between a hanging wall and an opposed foot wall.
- An object of the invention is to provide a support prop which can be pre-stressed, at the time of installation, so that the prop can provide its rated load-bearing capability as soon as possible and which, thereafter, can yield at a controlled rate which can be varied, within reason, according to requirement by user selection process.
- the invention provides a support prop which includes:
- the seal is preferably a cup seal positioned at a periphery of the closure, facing said volume. In this way a positive pressure effect is achieved i.e. as the pressure in the volume increases the effectiveness of the seal is automatically increased.
- the wedge member may be one of a plurality of similar wedge members.
- the invention is not limited in this regard.
- the wedge member includes a body which, in said axial direction, is tapered in cross-section and which, in cross-section in a direction which is transverse to said axial direction, has a curved shape.
- a surface of the wedge member which opposes said outer surface is serrated.
- FIG. 1 illustrates in cross-section a support prop according to the invention
- FIGS. 2 and 3 are different views of a wedge member used in the support prop.
- FIG. 1 of the accompanying drawing illustrates from one side and in cross-section a support prop 10 according to the invention.
- the prop includes an outer elongate tubular member 12 with an inner surface 14 , a first end 16 which has an open mouth 18 , a second end 20 , and a plate 22 which is welded to the second end so as to seal the second end.
- the prop further includes an inner elongate tubular member 38 with an outer surface 30 , a leading end 32 , a closure 34 which is engaged with and which seals the leading end, and a trailing end 36 which is covered by a plate 38 .
- a cup seal 40 is fixed to a peripheral edge 42 of the closure.
- the cup seal automatically is in sealing contact with the closure.
- the cup seal bears on the inner surface 14 and is in sliding contact therewith.
- a pressure relief valve 50 is fixed to the closure and overlies an aperture 52 in the closure.
- the pressure relief valve is of a type known in the art and allows liquid to flow through inlet apertures 54 in a side of the valve to an outlet 56 which is aligned with the aperture 52 when the pressure difference between the inlet and outlet apertures exceeds a predetermined level.
- the level can be set according to requirement using techniques which are known in the art.
- a one-way inlet valve 60 is fixed to the outer tubular member 12 .
- the valve 60 is in communication with a volume 62 which is bounded by the closure, part of the inner surface 14 and the plate 22 .
- the mouth 18 of the member 12 is slightly flared.
- a number of wedge members 70 are located in a small annular interface between opposing sections of the outer surface 30 and of the inner surface 14 .
- FIG. 2 shows, on an enlarged scale, a wedge member 70 from one end while FIG. 3 shows the wedge member in cross-section, taken on a line 3 - 3 in FIG. 2 .
- the wedge member has a body 74 which is curved.
- the curvature corresponds to the curvature of the interface between the outer surface 30 and the inner surface 14 of the tubular members.
- the body 74 has an inner side 76 and an outer side 78 . Referring to FIG. 3 it can be seen that the body has a tapered dimension and decreases in cross-sectional dimension from an upper end 80 towards a lower end 82 .
- the inner surface 76 is stepped, and is formed with a number of serrations 84 .
- the outer surface 78 is smooth.
- a small channel 90 is formed, in a circumferential sense, in the outer surface.
- the wedge member has a first wedge angle 84 A which is of the order of 15° and which facilitates placement of the wedge member between opposing surfaces of the inner and outer tubular members. This is followed by an increased wedge angle 84 B which typically is of the order of 25°.
- a tie is positioned in the channel 90 to keep the wedge member attached to the remainder of the support, e.g. for transport and storage purposes.
- the plate 22 is positioned on a foot wall 94 in an underground excavation 96 and plate 38 at the trailing end is opposing a hanging wall 98 in the excavation.
- Pressurized liquid e.g. water
- the volume 62 is expanded in an axial direction 100 and the tubular members are thereby telescopically extended.
- the pressure inside the volume 62 is well below the release pressure of the valve 50 .
- the volume 62 is pressurized in order to bring opposing surfaces of the prop into contact with the foot wall and the hanging wall respectively. Further pressurization places the prop under an axially directed compressive loading force, to a predetermined level, to pre-stress the prop. This is a desirable feature for it enables the prop to take up its desired load-bearing capability at the time of installation.
- a number of the wedge members 70 are placed into the gap between the flared mouth 18 and the outer surface 30 .
- the wedge members are tapped into the interface using a hammer or similar tool. In this way the serrations 84 are brought into frictional and mechanical engagement with the outer surface 30 .
- leading wedge angle 84 A is relatively small, about 15°, and this helps in the initial placement of each wedge member into the gap.
- the pressure in the volume 62 is increased.
- water can flow through the apertures 52 and exit from the valve into the interior of the tubular member 30 .
- This provides a pressure release function and the prop is therefore capable of yielding at a controlled rate which is determined by the setting of the valve.
- the wedge members are formed between the outer surface 30 and the inner surface 14 .
- the inner tubular member can only move into the outer tubular member if the wedge members deform the inner tubular member.
- the deformation of the inner tubular member is primarily attributable to the increase in the wedge angle to 84 B. It is this wedge angle which can be varied to control the yielding action of the prop, in one respect.
- the inner tubular member is preferably made of a thinner gauge material than the outer tubular member. This promotes deformation of the inner tubular member, rather than the outer tubular member. This occurs despite the serrations 84 which assist to drag each wedge to the end of the flared portion of the outer tubular member.
- the net effect is that the yielding action of the prop is controlled by two factors, namely the setting of the pressure relief valve and the deformation action of the wedge members.
- the pressure relief valve can be chosen according to requirement and its setting can be determined beforehand taking into account a particular application, yield rate and the like. Similar considerations apply in respect of the wedge members. Firstly, the number of wedge members can be varied. Secondly, the size of each wedge member and, in particular, its length and wedge angle can also be varied according to requirement to achieve an appropriate yielding effect.
- the wedge angle 84 B is, as noted, typically of the order of 25°. It can be varied from as low as 15° to promote rapid yielding to a value as high as 40° to create a situation in which a high force is required before yielding takes place. A particular benefit in this respect is that, at the time of installation, a particular yielding action can be provided for purely by selecting and using the wedge members appropriately.
Landscapes
- 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)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
A support prop which includes telescopically interengaged inner and outer tubular members, a one-way valve for introducing pressurized liquid into a volume inside at least one of the members, a pressure relief valve for releasing liquid from the volume when the liquid pressure in the volume exceeds a predetermined value and a number of wedges which are located between opposing surfaces of the tubular members and which are engaged with one member and which deform the inner member when telescopic yielding action of the members takes place.
Description
- This invention relates to a support prop suitable for use in an underground excavation, for providing support between a hanging wall and an opposed foot wall.
- An object of the invention is to provide a support prop which can be pre-stressed, at the time of installation, so that the prop can provide its rated load-bearing capability as soon as possible and which, thereafter, can yield at a controlled rate which can be varied, within reason, according to requirement by user selection process.
- The invention provides a support prop which includes:
- (a) an outer elongate tubular member with an inner surface, an interior bounded by the inner surface, a first end which has an open mouth, a second end and a plate which is engaged with, and which seals, the second end,
- (b) an inner elongate tubular member with an outer surface, a leading end, a trailing end, and a closure which is engaged with, and which seals, the leading end,
- (c) the inner tubular member and the outer tubular member being aligned in an axial direction with said leading end being inserted into said open mouth so that the inner tubular member extends telescopically into the outer tubular member,
- (d) a seal which is engaged with the closure and which is in sliding contact with said inner surface whereby a volume in at least the outer tubular member is enclosed by a portion of said inner surface, the plate and the closure at said leading end,
- (e) an inlet valve, secured to the outer tubular member, through which liquid can be introduced into said volume thereby to pressurise the volume,
- (f) a pressure relief valve engaged with the closure, the pressure relief valve allowing liquid, in the volume, at a pressure in excess of a predetermined level, to flow from the volume through the pressure relief valve into said interior,
- (g) at least one wedge member located between opposing sections of said outer surface and said inner surface, and
- (h) wherein the inner tubular member is movable in said axial direction into the outer tubular member against a yielding force which is determined by
- (i) said predetermined pressure level, and
- (ii) deformation of the inner tubular member by the at least one wedge member which is movable, together with the inner tubular member, into the outer tubular member.
- The seal is preferably a cup seal positioned at a periphery of the closure, facing said volume. In this way a positive pressure effect is achieved i.e. as the pressure in the volume increases the effectiveness of the seal is automatically increased.
- The wedge member may be one of a plurality of similar wedge members. The invention is not limited in this regard. Preferably the wedge member includes a body which, in said axial direction, is tapered in cross-section and which, in cross-section in a direction which is transverse to said axial direction, has a curved shape. Preferably a surface of the wedge member which opposes said outer surface is serrated.
- The invention is further described by way of example with reference to the accompanying drawings in which:
-
FIG. 1 illustrates in cross-section a support prop according to the invention, and -
FIGS. 2 and 3 are different views of a wedge member used in the support prop. -
FIG. 1 of the accompanying drawing illustrates from one side and in cross-section asupport prop 10 according to the invention. - The prop includes an outer elongate
tubular member 12 with aninner surface 14, afirst end 16 which has anopen mouth 18, asecond end 20, and aplate 22 which is welded to the second end so as to seal the second end. - The prop further includes an inner elongate
tubular member 38 with anouter surface 30, a leadingend 32, aclosure 34 which is engaged with and which seals the leading end, and atrailing end 36 which is covered by aplate 38. - A
cup seal 40 is fixed to aperipheral edge 42 of the closure. The cup seal automatically is in sealing contact with the closure. The cup seal bears on theinner surface 14 and is in sliding contact therewith. - A
pressure relief valve 50 is fixed to the closure and overlies anaperture 52 in the closure. The pressure relief valve is of a type known in the art and allows liquid to flow throughinlet apertures 54 in a side of the valve to anoutlet 56 which is aligned with theaperture 52 when the pressure difference between the inlet and outlet apertures exceeds a predetermined level. The level can be set according to requirement using techniques which are known in the art. - A one-
way inlet valve 60 is fixed to the outertubular member 12. Thevalve 60 is in communication with avolume 62 which is bounded by the closure, part of theinner surface 14 and theplate 22. - The
mouth 18 of themember 12 is slightly flared. A number ofwedge members 70 are located in a small annular interface between opposing sections of theouter surface 30 and of theinner surface 14. -
FIG. 2 shows, on an enlarged scale, awedge member 70 from one end whileFIG. 3 shows the wedge member in cross-section, taken on a line 3-3 inFIG. 2 . - The wedge member has a
body 74 which is curved. The curvature corresponds to the curvature of the interface between theouter surface 30 and theinner surface 14 of the tubular members. - The
body 74 has aninner side 76 and anouter side 78. Referring toFIG. 3 it can be seen that the body has a tapered dimension and decreases in cross-sectional dimension from anupper end 80 towards alower end 82. Theinner surface 76 is stepped, and is formed with a number ofserrations 84. Theouter surface 78 is smooth. Asmall channel 90 is formed, in a circumferential sense, in the outer surface. - The wedge member has a
first wedge angle 84A which is of the order of 15° and which facilitates placement of the wedge member between opposing surfaces of the inner and outer tubular members. This is followed by an increasedwedge angle 84B which typically is of the order of 25°. - A tie, not shown, is positioned in the
channel 90 to keep the wedge member attached to the remainder of the support, e.g. for transport and storage purposes. - In use of the prop the
plate 22 is positioned on afoot wall 94 in anunderground excavation 96 andplate 38 at the trailing end is opposing ahanging wall 98 in the excavation. Pressurized liquid, e.g. water, is introduced through the one-way filler valve 60 into thevolume 62. At this stage thewedge members 70 are not present. Thevolume 62 is expanded in anaxial direction 100 and the tubular members are thereby telescopically extended. The pressure inside thevolume 62 is well below the release pressure of thevalve 50. - The
volume 62 is pressurized in order to bring opposing surfaces of the prop into contact with the foot wall and the hanging wall respectively. Further pressurization places the prop under an axially directed compressive loading force, to a predetermined level, to pre-stress the prop. This is a desirable feature for it enables the prop to take up its desired load-bearing capability at the time of installation. - After the prop has been hydraulically installed, in the manner described, a number of the
wedge members 70 are placed into the gap between the flaredmouth 18 and theouter surface 30. The wedge members are tapped into the interface using a hammer or similar tool. In this way theserrations 84 are brought into frictional and mechanical engagement with theouter surface 30. - As noted the leading
wedge angle 84A is relatively small, about 15°, and this helps in the initial placement of each wedge member into the gap. - If closure of the hanging and foot wall takes place then the pressure in the
volume 62 is increased. When the release pressure of thevalve 50 is exceeded water can flow through theapertures 52 and exit from the valve into the interior of thetubular member 30. This provides a pressure release function and the prop is therefore capable of yielding at a controlled rate which is determined by the setting of the valve. The wedge members are formed between theouter surface 30 and theinner surface 14. The inner tubular member can only move into the outer tubular member if the wedge members deform the inner tubular member. - The deformation of the inner tubular member is primarily attributable to the increase in the wedge angle to 84B. It is this wedge angle which can be varied to control the yielding action of the prop, in one respect.
- The inner tubular member is preferably made of a thinner gauge material than the outer tubular member. This promotes deformation of the inner tubular member, rather than the outer tubular member. This occurs despite the
serrations 84 which assist to drag each wedge to the end of the flared portion of the outer tubular member. - The net effect is that the yielding action of the prop is controlled by two factors, namely the setting of the pressure relief valve and the deformation action of the wedge members.
- The pressure relief valve can be chosen according to requirement and its setting can be determined beforehand taking into account a particular application, yield rate and the like. Similar considerations apply in respect of the wedge members. Firstly, the number of wedge members can be varied. Secondly, the size of each wedge member and, in particular, its length and wedge angle can also be varied according to requirement to achieve an appropriate yielding effect. The
wedge angle 84B is, as noted, typically of the order of 25°. It can be varied from as low as 15° to promote rapid yielding to a value as high as 40° to create a situation in which a high force is required before yielding takes place. A particular benefit in this respect is that, at the time of installation, a particular yielding action can be provided for purely by selecting and using the wedge members appropriately.
Claims (5)
1. A support prop which includes:
(a) an outer elongate tubular member with an inner surface, an interior bounded by the inner surface, a first end which has an open mouth, a second end, and a plate which is engaged with, and which seals, the second end,
(b) an inner elongate tubular member with an outer surface, a leading end, a trailing end, and a closure which is engaged with, and which seals, the leading end,
(c) the inner tubular member and the outer tubular member being aligned in an axial direction with said leading end being inserted into said open mouth so that the inner tubular member extends telescopically into the outer tubular member,
(d) a seal which is engaged with the closure and which is in sliding contact with said inner surface whereby a volume in at least the outer tubular member is enclosed by a portion of said inner surface, the plate and the closure at said leading end,
(e) an inlet valve, secured to the outer tubular member, through which liquid can be introduced into said volume thereby to pressurise the volume,
(f) a pressure relief valve engaged with the closure, the pressure relief valve allowing liquid, in the volume, at a pressure in excess of a predetermined level, to flow from the volume through the pressure relief valve into said interior,
(g) at least one wedge member located between opposing sections of said outer surface and said inner surface, and
(h) wherein the inner tubular member is movable in said axial direction into the outer tubular member against a yielding force which is determined by
(i) said predetermined pressure level, and
(ii) deformation of the inner tubular member by the at least one wedge member which is movable, together with the inner tubular member, into the outer tubular member.
2. A support prop according to claim 1 wherein the seal comprises a cup seal, on a periphery of the closure, which faces said volume.
3. A support prop according to claim 1 wherein the wedge member includes a body which, in said axial direction, is tapered in cross-section, and which, in cross-section in a direction which is transverse to said axial direction, has a curved shape.
4. A support prop according to claim 3 wherein a surface of the wedge member, which opposes said outer surface, is serrated.
5. A support prop according to claim 3 wherein said tapered cross-section has a wedge angle of from 15° to 40°.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/651,926 US20140072374A1 (en) | 2012-09-07 | 2012-10-15 | Support prop |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201213606512A | 2012-09-07 | 2012-09-07 | |
US13/651,926 US20140072374A1 (en) | 2012-09-07 | 2012-10-15 | Support prop |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US201213606512A Continuation-In-Part | 2012-09-07 | 2012-09-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20140072374A1 true US20140072374A1 (en) | 2014-03-13 |
Family
ID=50233428
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/651,926 Abandoned US20140072374A1 (en) | 2012-09-07 | 2012-10-15 | Support prop |
Country Status (1)
Country | Link |
---|---|
US (1) | US20140072374A1 (en) |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1765200A (en) * | 1927-11-17 | 1930-06-17 | Bullough Enoch | Pit prop |
US3292892A (en) * | 1965-10-14 | 1966-12-20 | Oscar J Abbott | Adjustable form shore |
US4167361A (en) * | 1978-08-30 | 1979-09-11 | Mine Safety Appliances Company | Temporary mine roof prop |
US4185940A (en) * | 1977-11-08 | 1980-01-29 | Klaus Spies | Method and system for supporting a roof |
US5165824A (en) * | 1991-02-11 | 1992-11-24 | Corcoran Dan M | Elongated shoring device |
US5273378A (en) * | 1991-05-10 | 1993-12-28 | Volker Merz | Support column |
US5413436A (en) * | 1993-05-17 | 1995-05-09 | Mbk-Hydraulik Meuwsen & Brockhausen Gmbh | Support column |
US5564867A (en) * | 1993-11-13 | 1996-10-15 | Bochumer Eisenhutte Heintzmann Gmbh & Co. Kg | Resilienty compressible support column for use in a mine |
US5720581A (en) * | 1993-05-07 | 1998-02-24 | Dorbyl Limited | Support prop |
US5921718A (en) * | 1995-04-20 | 1999-07-13 | Kolk; Theodor | Prop for use in underground mining or tunnel construction |
US6056480A (en) * | 1995-04-20 | 2000-05-02 | Kolk; Theodor | Support for underground mining and tunnel construction |
-
2012
- 2012-10-15 US US13/651,926 patent/US20140072374A1/en not_active Abandoned
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1765200A (en) * | 1927-11-17 | 1930-06-17 | Bullough Enoch | Pit prop |
US3292892A (en) * | 1965-10-14 | 1966-12-20 | Oscar J Abbott | Adjustable form shore |
US4185940A (en) * | 1977-11-08 | 1980-01-29 | Klaus Spies | Method and system for supporting a roof |
US4167361A (en) * | 1978-08-30 | 1979-09-11 | Mine Safety Appliances Company | Temporary mine roof prop |
US5165824A (en) * | 1991-02-11 | 1992-11-24 | Corcoran Dan M | Elongated shoring device |
US5273378A (en) * | 1991-05-10 | 1993-12-28 | Volker Merz | Support column |
US5720581A (en) * | 1993-05-07 | 1998-02-24 | Dorbyl Limited | Support prop |
US5413436A (en) * | 1993-05-17 | 1995-05-09 | Mbk-Hydraulik Meuwsen & Brockhausen Gmbh | Support column |
US5564867A (en) * | 1993-11-13 | 1996-10-15 | Bochumer Eisenhutte Heintzmann Gmbh & Co. Kg | Resilienty compressible support column for use in a mine |
US5921718A (en) * | 1995-04-20 | 1999-07-13 | Kolk; Theodor | Prop for use in underground mining or tunnel construction |
US6056480A (en) * | 1995-04-20 | 2000-05-02 | Kolk; Theodor | Support for underground mining and tunnel construction |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ELBROC MINING PRODUCTS (PTY) LTD, SOUTH AFRICA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ROACH, GRANT;CHALMERS, GRAEME;REEL/FRAME:029132/0474 Effective date: 20121003 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |