CA2045274C - Prop preloading apparatus - Google Patents
Prop preloading apparatusInfo
- Publication number
- CA2045274C CA2045274C CA 2045274 CA2045274A CA2045274C CA 2045274 C CA2045274 C CA 2045274C CA 2045274 CA2045274 CA 2045274 CA 2045274 A CA2045274 A CA 2045274A CA 2045274 C CA2045274 C CA 2045274C
- Authority
- CA
- Canada
- Prior art keywords
- frame
- prop
- bag
- limbs
- tray
- 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 - Fee Related
Links
- 230000036316 preload Effects 0.000 claims abstract description 13
- 239000000126 substance Substances 0.000 claims abstract description 9
- 229910000831 Steel Inorganic materials 0.000 claims description 15
- 239000010959 steel Substances 0.000 claims description 15
- 239000011440 grout Substances 0.000 claims description 6
- 238000010276 construction Methods 0.000 claims description 5
- 230000000452 restraining effect Effects 0.000 claims description 4
- 239000000945 filler Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000004677 Nylon Substances 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 230000003245 working effect Effects 0.000 description 1
Landscapes
- Revetment (AREA)
- Specific Conveyance Elements (AREA)
Abstract
The prop preloading apparatus comprises a frame and means for supporting the frame on an end of an elongate prop in a manner permitting at least limited swivelling movement of the frame relative to the prop about at least one axis transverse to the axis of the prop. The apparatus also includes a flexible preload bag which is inflatable with a settable substance and which is dimensioned to besupported by the frame.
Description
2~1~527~
BACKGROUND TO THE INVENTION
THIS invention relates to a preloading apparatus for an elongate prop such as isused in underground mines to provide a yielding support for a h~n~ing wall relative to a footwall.
A large proportion of the elongate props used under~,loulld in mines comprise orconsist of a timber pole. In use, the pole is cut to length and the prop is arranged upright between the h~nging and foot walls. The prop is then wedged into position between the h~nging and foot walls by means of separate timber wedges which are hammered into position between the upper end of the prop and the h~nging wall.
This wedging of the prop gives it stability to plcvenl it from falling over whennearby blasting takes place or the prop is impacted by under~oulld personnel or equipment.
In addition to merely wedging the prop in position, however, it would be desirable to apply to it some co~ ressive force such that the prop is immediately ready totake the full co~ ressive load which is imposed thereon when the h~nging wall closes on the footwall with passage of time.
SUMMARY OF THE INVENTION
A flrst aspect of the lnventlon provldes a prop preloadlng apparatus comprlslng a frame, means for supportlng the frame on an end of an elongate prop ln a manner permlttlng at least llmlted swlvelllng movement of the frame relatlve to the prop about at least one axls transverse to the axls of the prop, and a flexlble preload bag whlch ls lnflatable with a settable substance and whlch ls dlmensloned to be supported by the frame, whereln the frame lncludes a support member ln the form of a tray for recelving and supportlng the bag and whereln the apparatus includes a cover member which makes a telescoplc flt wlth the tray and whlch, ln comblnatlon wlth the support member, forms an enclosure for the bag.
The means for supportlng the frame on the end of the prop may lnclude an open-ended pot for recelvlng the head of the prop and means connectlng the tray to the pot ln a manner permlttlng the tray to bear upon the pot and to plvot relatlve to the pot about an axls transverse to the prop axls. The tray may have an arcuate bearlng surface whlch bears upon a complemental arcuate surface on the pot.
The lnventlon also provldes a prop preloadlng unlt comprlslng a frame of open constructlon and made up of elongate frame members, the frame lncluding a strap for passlng over the end of an elongate prop for supporting the frame on the end of the prop, and the frame belng adapted to support a flexlble preload bag whlch ls lnflatable with a settable substance, whereln the frame presents spaced apart limbs arranged to 204527~
locate on opposite sldes of the end of the prop and wherein the frame lncludes re-entrant restralnlng members flxed to opposlte edges of the frame to embrace opposlte edge reglons of the lnflatable bag thereby to restraln transverse movement of the bag relative to the frame.
The lnventlon also provldes such a prop preloadlng unlt ln comblnatlon wlth an lnflatable preload bag dlmensloned to be supported by the frame and adapted to be lnflated by settable grout under pressure.
Convenlently, but not necessarlly, the strap ls flexlble.
Typlcally, the frame ls an open frame presentlng spaced apart, V-shaped llmbs whlch locate ln use on opposlte sldes of the end of the prop. The frame preferably lncludes a pair of spaced members whlch span between the arms of the respectlve V-shaped llmbs, whlch recelve the end of the prop between them ln use, and whlch deflne the limlt of swlvelllng movement of the frame relatlve to the prop. Convenlently, the restralnlng means comprlse sheets of steel flxed to opposlte ends of the frame, the sheets belng bent lnwardly towards one another to deflne spaces between themselves and the frame lnto whlch the ends of the bag can be lnserted.
For ease of transportatlon, lt ls preferred that the ends of the strap are flxed to the llmbs at posltlons ad~acent to but off-set from the aplces of the V-shapes, the arrangement belng such that the frame can stack compactly wlth another slmllar frame wlth the llmbs nestlng snugly wlthln the llmbs of the other frame. For lightness, lt is preferred that the llmbs are of tubular steel and are connected to one another by tubular steel ~oining portions at opposite ends of the frame.
The bag has the same structure as a PACK SETTER bag.
BRIEF DESCRIPTION OF THE DRAWINGS
The lnvention wlll now be descrlbed ln more detall, by way of example only, wlth reference to the accompanylng drawlngs ln whlch:
Flgure 1 shows a slde vlew of the upper end of an elongate prop fltted wlth a flrst embodlment of a devlce of the lnventlon prlor to lnflatlon of the bag;
Flgure 2 shows a slmllar vlew of the device shown in Flgure 1 wlth the bag lnflated;
Flgure 3 shows a perspectlve vlew of a headboard settlng frame of the lnventlon;
Flgure 4 shows a slde vlew of the frame of Flgure 3 ln use;
, 64840-62 -6- 2~4 '~
Figure 5 shows and end view of what is seen in Figure 3;
Figure 6 shows a view similar to Figure 5, but with the device fitted on a prop of larger diameter;
Figure 7 shows a plan view of the infl~t~ble bag used for prelo~-ling;
Figure 8 shows a plan view of the frame seen in Figures 3 to 6; and Figure 9 shows how frames of the kind seen in Figure 3 can be stacked compactly together.
DESCRIPIION OF EMBODIMENTS
Referring firstly to Figures 1 and 2, the numeral 10 refers to the upper end of a typical elongate prop, such as the well known PIPESTICK The prop inclllcles a timber pole 12 which is received within a steel pot 14 having a base 16 which isarcuate in one plane. A shallow steel tray 18 having a base 20 and side walls ~ is pivoted to the pot by means of brackets 24 and pivot pins 26. Only one bracket and pivot pin combination is visible in the Figures, but it will be appreciated that a similar bracket and pin combination is provided symmetrically on the opposite side of the pot 14.
At the junctions of the side walls 22 and the base 20 of the tray 18, rehlrorcelllent is provided by lengths 30 of angle section steel.
7 2~ ~27~
A cover member 32 of open-top box shape and formed of steel mesh, ~Yp~ncled metal or the like is inverted over the tray 18 and makes a telescopic fit with the tray. In combination, the tray 18 and cover member form a rect~n~ r enclosure of variable height.
The device of the invention also includes a liquid-tight bag 34 which has a filler nozzle 36. The bag 34is sized to rest upon the tray and to fit into the enclosure defined by the tray and cover member. The filler nozzle 36 protrudes through an opening in the base of the tray and is ~cces~ihle from below through the open end of the cover member 32.
In use, with the device of the invention installed at the end of the prop and with the bag empty and in position as illustrated in Figure 1, the prop is arranged at anupright attitude between a h~nging wall 38 and a footwall (not visible in the drawings). The prop has already been cut to such a length that with the bottom end of the prop resting upon the footwall, the cover member 32is spaced a short distance below the h~nging wall.
A conduit extending from a pumped supply of a suitable cementitious mix or othersettable substance is connected up to the filler nozzle 36 and the grout is pumped into the bag to cause it to inflate. As the bag infl~tes~ the cover member 32 telescopes apart from the tray and eventually presses up against the h~nging wall.
the material of which the cover member is made is preferably fairly flexible so that it can take up the irregular shape of the h~nging wall.
With a suitable p~ ing pressure, a preload force of predetermined m~gnitllcle, typically a m~gnit~l~e of some tons, can be applied to the prop. The filler nozzle includes a non-return valve of any suitable killd to prevt;l~t the settable substance from flowing back out of the bag once a desired internal pressure has been attained -8- 2~ ?~
and the feed conduit is disconnected from the nozzle. The settable substance nowsets to m~int~in the desired compressive preload force on the prop.
Once preloaded in this way to an applo~liate level, the prop will immediately bein the condition to accept further colll~ressive load as the h~nging wall closes on the footwall with passage of time.
An important feature of the device described above is the provision for swivelling movement of the tray relative to the prop. As stated previously, the base 16 of the pot 14 is arcuate in one plane. The curvature of the base is matched by an arcuate depression 40 in the base 20 of the tray 18. The depression and the base of the pot mate with one another as illustrated and, with the described arrangement of brackets 24 and pins 26, the tray is capable of swivelling relative to the pot in one plane as indicated by the reference numeral 42. With this arrangement it is possible to orientate the prop, about its own axis, to suit any dip in the h~nging wall before the bag is inflated to lock the prop in position. Figure 2 shows the h~nging wall to have a substantial dip relative to the hori70nt~1, with the tray, cover member and bag orientated at the correct ~ttit~1de to suit the dip.
Figure 3 shows a perspective view of a preferred headboard setting frame. The frame 50 ha a tubular steel member 52 bent to the illustrated shape so as to provide two V-shaped, downwardly depending limbs 53. A stirrup 54 has its ends ~tt~ed to the dowllwardly depending limbs at position~ close to the apices thereof as illustrated.
The stirrup may be in the form of a rigid, U-shaped steel strap. Alternatively, it may be of flexible material, typically a thin gauge steel band or flexible woven webbing, say of nylon.
9 - 2 ~
In use, as illustrated in Figures 4 to 6, the headboard setting frame is arranged on the upper end of an elongate prop which, as in the first embodiment, incllldes atimber pole 56. When properly installed, the limbs 53 are located on opposite sides of the upper end of the timber pole, as will be particularly clear from Figures 4 and 5. The stirrup 54 passes over the head of the prop as illustrated, and ~revenls the frame from moving downwardly relative to the timber pole.
Figure 4 shows a timber pole of small diameter, while Figure S shows a prop of somewhat larger diameter. It will be appreciated that, if the stirrup is of flexible material, the same frame can be used with both props. On the other hand, if the stirrup is of rigid material, this component may have to be modified slightly for different prop diameters. Even in the latter case, the other components of the frame are unchanged. Thus the frame has a good deal of versatility to take account of different prop diameters.
Spanning between the V-shaped limbs 53 are members 58. The spacing between these members is somewhat greater than the largest diameter prop with which the frame will be used. Thus the frame is capable of at least limited pivotal or swivelling movement relative to the prop before the side of the prop abuts the relevant member 58. In Figure 4, the limited swivelling movement is about an axis into the plane of the paper. At the same time, because of the sp~cing between the limbs 53 and the sides of the prop, a limited degree of swivelling movement is permitted about a horizontal axis at right angles to the axis just referred to.
Figures 4, 5 and 6 also show an infl~t~ble bag 60 with its filler nozzle 61. The bag 60, which can be identical to the bag 34 of the first embodiment, is made of anysuitable material that can remain liquid tight while still withst~n(1ing the imposed loads in use. A typical construction for the bag will be that used for the knownPACK ~ l l ~K bags that are used to preload mat packs in mine workings.
2 7 i As illustrated, the bag 60 is placed on the head of the prop and is supported both by the prop itself and by cross-members 62 which span across the frame. An important feature of the frame design illustrated by Figures 3 to 6is the provision of restraining members 64. These members are in the form of rect~n~ r sheets of thin gauge steel. The sheets are welded to undersides of the end portions 66 of the frame 50 and are then bent over the ends of the bag 60 as illustrated. In practice, the sheets are bent over at the outset, and the un-inflated bag is slipped beneath them.
Once the frame, with the un-infl~te~l bag is installed on the head of the prop, the ~iopliate grout is pumped into the bag through the filler nozle 61. The preferred grout is that used in conjunction with the aforementioned PACK ~ l l 1;~ bags. As the bag is inflated with the grout under pressure, a preload force of some m~gnit~l~le is applied to the prop to preload it in the axial direction.
To l~rt;venl the V-shaped limbs 53 from splaying apart, i.e. in the sense to increase their apex angles, braces 70 are provided that span across the bases of the limbs 53 as illustrated. Usually, the braces will be in the form of steel rods or strips, but flexible braces may also be used. As a less preferred alternative to providing the braces on the frame itself, it is possible to incorporate longitll~lin~l braces within the bag 60. It will be appreciated that the cross-members 62 also prevenl splaying apart of the limbs, i.e. in the sense in which the limbs actually move away from one another as load is applied.
Another advantageous feature of the frame 50is its ability to stack compactly with other similar frames, as illustrated in Figure 9. It will be appreciated that with rigid stirrups 54, it is necessary to off-set their connection points to the limbs 53 as described above and as illustrated so that efflcient stacking can take place. Naturally the compactness with which the frames can be stacked facilitates their transport, 11 - 2 ~ J ~;? ,;~"
both to a mine and to underground sites within the mine.
The major component of each frame is of course the member 52. Being of tubular construction, the member 52 and, as a result, the entire frame, is quite light and is easily m~nh~n(1led.
Referring again to the resLlAi~ g members 64, it will be noted in Figure 4 that the h~nging wall bears against these members and that they prevent movement of the bag relative to the prop in the direction 72. Thus the bag is held in the correct position on top of the prop even if the prop should skew slightly.
In other versions of the frame 50, the stirrup 54 could be omitted. In such cases, it would be necessary to provide some or other means to prevent dowllward movement of the frame relative to the prop as co~ lessive loading is applied. This could be achieved suitable clamps or spikes on the frame to grip the periphery of the timber pole.
Accordhlg to a further alternative contemplated by the invention, the frame 50 could be of hinged construction, enabling it to be folded compactly for tra~nsportation. Typically, hinges could be provided at the apices of the V-shaped limbs 53.
BACKGROUND TO THE INVENTION
THIS invention relates to a preloading apparatus for an elongate prop such as isused in underground mines to provide a yielding support for a h~n~ing wall relative to a footwall.
A large proportion of the elongate props used under~,loulld in mines comprise orconsist of a timber pole. In use, the pole is cut to length and the prop is arranged upright between the h~nging and foot walls. The prop is then wedged into position between the h~nging and foot walls by means of separate timber wedges which are hammered into position between the upper end of the prop and the h~nging wall.
This wedging of the prop gives it stability to plcvenl it from falling over whennearby blasting takes place or the prop is impacted by under~oulld personnel or equipment.
In addition to merely wedging the prop in position, however, it would be desirable to apply to it some co~ ressive force such that the prop is immediately ready totake the full co~ ressive load which is imposed thereon when the h~nging wall closes on the footwall with passage of time.
SUMMARY OF THE INVENTION
A flrst aspect of the lnventlon provldes a prop preloadlng apparatus comprlslng a frame, means for supportlng the frame on an end of an elongate prop ln a manner permlttlng at least llmlted swlvelllng movement of the frame relatlve to the prop about at least one axls transverse to the axls of the prop, and a flexlble preload bag whlch ls lnflatable with a settable substance and whlch ls dlmensloned to be supported by the frame, whereln the frame lncludes a support member ln the form of a tray for recelving and supportlng the bag and whereln the apparatus includes a cover member which makes a telescoplc flt wlth the tray and whlch, ln comblnatlon wlth the support member, forms an enclosure for the bag.
The means for supportlng the frame on the end of the prop may lnclude an open-ended pot for recelvlng the head of the prop and means connectlng the tray to the pot ln a manner permlttlng the tray to bear upon the pot and to plvot relatlve to the pot about an axls transverse to the prop axls. The tray may have an arcuate bearlng surface whlch bears upon a complemental arcuate surface on the pot.
The lnventlon also provldes a prop preloadlng unlt comprlslng a frame of open constructlon and made up of elongate frame members, the frame lncluding a strap for passlng over the end of an elongate prop for supporting the frame on the end of the prop, and the frame belng adapted to support a flexlble preload bag whlch ls lnflatable with a settable substance, whereln the frame presents spaced apart limbs arranged to 204527~
locate on opposite sldes of the end of the prop and wherein the frame lncludes re-entrant restralnlng members flxed to opposlte edges of the frame to embrace opposlte edge reglons of the lnflatable bag thereby to restraln transverse movement of the bag relative to the frame.
The lnventlon also provldes such a prop preloadlng unlt ln comblnatlon wlth an lnflatable preload bag dlmensloned to be supported by the frame and adapted to be lnflated by settable grout under pressure.
Convenlently, but not necessarlly, the strap ls flexlble.
Typlcally, the frame ls an open frame presentlng spaced apart, V-shaped llmbs whlch locate ln use on opposlte sldes of the end of the prop. The frame preferably lncludes a pair of spaced members whlch span between the arms of the respectlve V-shaped llmbs, whlch recelve the end of the prop between them ln use, and whlch deflne the limlt of swlvelllng movement of the frame relatlve to the prop. Convenlently, the restralnlng means comprlse sheets of steel flxed to opposlte ends of the frame, the sheets belng bent lnwardly towards one another to deflne spaces between themselves and the frame lnto whlch the ends of the bag can be lnserted.
For ease of transportatlon, lt ls preferred that the ends of the strap are flxed to the llmbs at posltlons ad~acent to but off-set from the aplces of the V-shapes, the arrangement belng such that the frame can stack compactly wlth another slmllar frame wlth the llmbs nestlng snugly wlthln the llmbs of the other frame. For lightness, lt is preferred that the llmbs are of tubular steel and are connected to one another by tubular steel ~oining portions at opposite ends of the frame.
The bag has the same structure as a PACK SETTER bag.
BRIEF DESCRIPTION OF THE DRAWINGS
The lnvention wlll now be descrlbed ln more detall, by way of example only, wlth reference to the accompanylng drawlngs ln whlch:
Flgure 1 shows a slde vlew of the upper end of an elongate prop fltted wlth a flrst embodlment of a devlce of the lnventlon prlor to lnflatlon of the bag;
Flgure 2 shows a slmllar vlew of the device shown in Flgure 1 wlth the bag lnflated;
Flgure 3 shows a perspectlve vlew of a headboard settlng frame of the lnventlon;
Flgure 4 shows a slde vlew of the frame of Flgure 3 ln use;
, 64840-62 -6- 2~4 '~
Figure 5 shows and end view of what is seen in Figure 3;
Figure 6 shows a view similar to Figure 5, but with the device fitted on a prop of larger diameter;
Figure 7 shows a plan view of the infl~t~ble bag used for prelo~-ling;
Figure 8 shows a plan view of the frame seen in Figures 3 to 6; and Figure 9 shows how frames of the kind seen in Figure 3 can be stacked compactly together.
DESCRIPIION OF EMBODIMENTS
Referring firstly to Figures 1 and 2, the numeral 10 refers to the upper end of a typical elongate prop, such as the well known PIPESTICK The prop inclllcles a timber pole 12 which is received within a steel pot 14 having a base 16 which isarcuate in one plane. A shallow steel tray 18 having a base 20 and side walls ~ is pivoted to the pot by means of brackets 24 and pivot pins 26. Only one bracket and pivot pin combination is visible in the Figures, but it will be appreciated that a similar bracket and pin combination is provided symmetrically on the opposite side of the pot 14.
At the junctions of the side walls 22 and the base 20 of the tray 18, rehlrorcelllent is provided by lengths 30 of angle section steel.
7 2~ ~27~
A cover member 32 of open-top box shape and formed of steel mesh, ~Yp~ncled metal or the like is inverted over the tray 18 and makes a telescopic fit with the tray. In combination, the tray 18 and cover member form a rect~n~ r enclosure of variable height.
The device of the invention also includes a liquid-tight bag 34 which has a filler nozzle 36. The bag 34is sized to rest upon the tray and to fit into the enclosure defined by the tray and cover member. The filler nozzle 36 protrudes through an opening in the base of the tray and is ~cces~ihle from below through the open end of the cover member 32.
In use, with the device of the invention installed at the end of the prop and with the bag empty and in position as illustrated in Figure 1, the prop is arranged at anupright attitude between a h~nging wall 38 and a footwall (not visible in the drawings). The prop has already been cut to such a length that with the bottom end of the prop resting upon the footwall, the cover member 32is spaced a short distance below the h~nging wall.
A conduit extending from a pumped supply of a suitable cementitious mix or othersettable substance is connected up to the filler nozzle 36 and the grout is pumped into the bag to cause it to inflate. As the bag infl~tes~ the cover member 32 telescopes apart from the tray and eventually presses up against the h~nging wall.
the material of which the cover member is made is preferably fairly flexible so that it can take up the irregular shape of the h~nging wall.
With a suitable p~ ing pressure, a preload force of predetermined m~gnitllcle, typically a m~gnit~l~e of some tons, can be applied to the prop. The filler nozzle includes a non-return valve of any suitable killd to prevt;l~t the settable substance from flowing back out of the bag once a desired internal pressure has been attained -8- 2~ ?~
and the feed conduit is disconnected from the nozzle. The settable substance nowsets to m~int~in the desired compressive preload force on the prop.
Once preloaded in this way to an applo~liate level, the prop will immediately bein the condition to accept further colll~ressive load as the h~nging wall closes on the footwall with passage of time.
An important feature of the device described above is the provision for swivelling movement of the tray relative to the prop. As stated previously, the base 16 of the pot 14 is arcuate in one plane. The curvature of the base is matched by an arcuate depression 40 in the base 20 of the tray 18. The depression and the base of the pot mate with one another as illustrated and, with the described arrangement of brackets 24 and pins 26, the tray is capable of swivelling relative to the pot in one plane as indicated by the reference numeral 42. With this arrangement it is possible to orientate the prop, about its own axis, to suit any dip in the h~nging wall before the bag is inflated to lock the prop in position. Figure 2 shows the h~nging wall to have a substantial dip relative to the hori70nt~1, with the tray, cover member and bag orientated at the correct ~ttit~1de to suit the dip.
Figure 3 shows a perspective view of a preferred headboard setting frame. The frame 50 ha a tubular steel member 52 bent to the illustrated shape so as to provide two V-shaped, downwardly depending limbs 53. A stirrup 54 has its ends ~tt~ed to the dowllwardly depending limbs at position~ close to the apices thereof as illustrated.
The stirrup may be in the form of a rigid, U-shaped steel strap. Alternatively, it may be of flexible material, typically a thin gauge steel band or flexible woven webbing, say of nylon.
9 - 2 ~
In use, as illustrated in Figures 4 to 6, the headboard setting frame is arranged on the upper end of an elongate prop which, as in the first embodiment, incllldes atimber pole 56. When properly installed, the limbs 53 are located on opposite sides of the upper end of the timber pole, as will be particularly clear from Figures 4 and 5. The stirrup 54 passes over the head of the prop as illustrated, and ~revenls the frame from moving downwardly relative to the timber pole.
Figure 4 shows a timber pole of small diameter, while Figure S shows a prop of somewhat larger diameter. It will be appreciated that, if the stirrup is of flexible material, the same frame can be used with both props. On the other hand, if the stirrup is of rigid material, this component may have to be modified slightly for different prop diameters. Even in the latter case, the other components of the frame are unchanged. Thus the frame has a good deal of versatility to take account of different prop diameters.
Spanning between the V-shaped limbs 53 are members 58. The spacing between these members is somewhat greater than the largest diameter prop with which the frame will be used. Thus the frame is capable of at least limited pivotal or swivelling movement relative to the prop before the side of the prop abuts the relevant member 58. In Figure 4, the limited swivelling movement is about an axis into the plane of the paper. At the same time, because of the sp~cing between the limbs 53 and the sides of the prop, a limited degree of swivelling movement is permitted about a horizontal axis at right angles to the axis just referred to.
Figures 4, 5 and 6 also show an infl~t~ble bag 60 with its filler nozzle 61. The bag 60, which can be identical to the bag 34 of the first embodiment, is made of anysuitable material that can remain liquid tight while still withst~n(1ing the imposed loads in use. A typical construction for the bag will be that used for the knownPACK ~ l l ~K bags that are used to preload mat packs in mine workings.
2 7 i As illustrated, the bag 60 is placed on the head of the prop and is supported both by the prop itself and by cross-members 62 which span across the frame. An important feature of the frame design illustrated by Figures 3 to 6is the provision of restraining members 64. These members are in the form of rect~n~ r sheets of thin gauge steel. The sheets are welded to undersides of the end portions 66 of the frame 50 and are then bent over the ends of the bag 60 as illustrated. In practice, the sheets are bent over at the outset, and the un-inflated bag is slipped beneath them.
Once the frame, with the un-infl~te~l bag is installed on the head of the prop, the ~iopliate grout is pumped into the bag through the filler nozle 61. The preferred grout is that used in conjunction with the aforementioned PACK ~ l l 1;~ bags. As the bag is inflated with the grout under pressure, a preload force of some m~gnit~l~le is applied to the prop to preload it in the axial direction.
To l~rt;venl the V-shaped limbs 53 from splaying apart, i.e. in the sense to increase their apex angles, braces 70 are provided that span across the bases of the limbs 53 as illustrated. Usually, the braces will be in the form of steel rods or strips, but flexible braces may also be used. As a less preferred alternative to providing the braces on the frame itself, it is possible to incorporate longitll~lin~l braces within the bag 60. It will be appreciated that the cross-members 62 also prevenl splaying apart of the limbs, i.e. in the sense in which the limbs actually move away from one another as load is applied.
Another advantageous feature of the frame 50is its ability to stack compactly with other similar frames, as illustrated in Figure 9. It will be appreciated that with rigid stirrups 54, it is necessary to off-set their connection points to the limbs 53 as described above and as illustrated so that efflcient stacking can take place. Naturally the compactness with which the frames can be stacked facilitates their transport, 11 - 2 ~ J ~;? ,;~"
both to a mine and to underground sites within the mine.
The major component of each frame is of course the member 52. Being of tubular construction, the member 52 and, as a result, the entire frame, is quite light and is easily m~nh~n(1led.
Referring again to the resLlAi~ g members 64, it will be noted in Figure 4 that the h~nging wall bears against these members and that they prevent movement of the bag relative to the prop in the direction 72. Thus the bag is held in the correct position on top of the prop even if the prop should skew slightly.
In other versions of the frame 50, the stirrup 54 could be omitted. In such cases, it would be necessary to provide some or other means to prevent dowllward movement of the frame relative to the prop as co~ lessive loading is applied. This could be achieved suitable clamps or spikes on the frame to grip the periphery of the timber pole.
Accordhlg to a further alternative contemplated by the invention, the frame 50 could be of hinged construction, enabling it to be folded compactly for tra~nsportation. Typically, hinges could be provided at the apices of the V-shaped limbs 53.
Claims (11)
1. A prop preloading apparatus comprising a frame, means for supporting the frame on an end of an elongate prop in a manner permitting at least limited swivelling movement of the frame relative to the prop about at least one axis transverse to the axis of the prop, and a flexible preload bag which is inflatable with a settable substance and which is dimensioned to be supported by the frame, wherein the frame includes a support member in the form of a tray for receiving and supporting the bag and wherein the apparatus includes a cover member which makes a telescopic fit with the tray and which, in combination with the support member, forms an enclosure for the bag.
2. A prop preloading apparatus according to claim 1 wherein the means for supporting the frame on the end of the prop includes an open-ended pot for receiving the head of the prop and means connecting the tray to the pot in a manner permitting the tray to pivot relative to the pot about an axis transverse to the prop axis.
3. A prop preloading apparatus according to claim 2 wherein the tray has an arcuate bearing surface which bears upon a complemental arcuate surface on the pot.
4. A prop preloading unit comprising a frame of open construction and made up of elongate frame members, the frame including a strap for passing over the end of an elongate prop for supporting the frame on the end of the prop, and the frame being adapted to support a flexible preload bag which is inflatable with a settable substance, wherein the frame presents spaced apart limbs arranged to locate on opposite sides of the end of the prop and wherein the frame includes re-entrant restraining members fixed to opposite edges of the frame to embrace opposite edge regions of the inflatable bag thereby to restrain transverse movement of the bag relative to the frame.
5. The prop preloading unit according to claim 4 wherein the restraining members comprise sheets of steel fixed to opposite ends of the frame, the sheets being bent inwardly on themselves to define spaces between themselves and the frame into which the ends of the bag can be inserted in use.
6. A prop preloading unit according to claim 4 wherein the limbs are V-shaped.
7. A prop preloading unit according to claim 6 wherein the frame includes a pair of spaced members which span between the arms of the respective V-shaped limbs, which receive the end of the prop between them in use, and which define a limit of swivelling movement of the frame relative to the prop in use.
8. A prop preloading unit according to claim 6 wherein the ends of the strap are fixed to the limbs at positions adjacent to but off-set from the apices of the V-shapes, the arrangement being such that the frame can stack compactly with another similar frame with the limbs nesting snugly with the limbs of the other frame.
9. A prop reloading unit according to claim 8 wherein the frame includes bracing members spanning across the base of each V-shaped limb to prevent the limbs from splaying under load.
10. A prop reloading unit according to claim 9 wherein the limbs are of tubular steel and are connected to one another by tubular steel joining portions at opposite ends of the frame.
11. The combination of:
(a) a prop preloading unit comprising a frame of open construction and made up of elongate frame members, the frame including a strap for passing over the end of an elongate prop for supporting the frame on the end of the prop, and the frame being adapted to support a flexible preload bag which is inflatable with a settable substance wherein the frame presents spaced apart limbs arranged to locate on opposite sides of the end of the prop, and wherein the frame includes re-entrant restraining members fixed to opposite edges of the frame to embrace opposite edge regions of the inflatable bag thereby to restrain transverse movement of the bag relative to the frame; and (b) an inflatable preload bag dimensioned to be supported by the frame and adapted to be inflated by settable grout under pressure.
(a) a prop preloading unit comprising a frame of open construction and made up of elongate frame members, the frame including a strap for passing over the end of an elongate prop for supporting the frame on the end of the prop, and the frame being adapted to support a flexible preload bag which is inflatable with a settable substance wherein the frame presents spaced apart limbs arranged to locate on opposite sides of the end of the prop, and wherein the frame includes re-entrant restraining members fixed to opposite edges of the frame to embrace opposite edge regions of the inflatable bag thereby to restrain transverse movement of the bag relative to the frame; and (b) an inflatable preload bag dimensioned to be supported by the frame and adapted to be inflated by settable grout under pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2045274 CA2045274C (en) | 1991-06-24 | 1991-06-24 | Prop preloading apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2045274 CA2045274C (en) | 1991-06-24 | 1991-06-24 | Prop preloading apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2045274A1 CA2045274A1 (en) | 1992-12-25 |
| CA2045274C true CA2045274C (en) | 1998-05-12 |
Family
ID=4147891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2045274 Expired - Fee Related CA2045274C (en) | 1991-06-24 | 1991-06-24 | Prop preloading apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2045274C (en) |
-
1991
- 1991-06-24 CA CA 2045274 patent/CA2045274C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2045274A1 (en) | 1992-12-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |