CA2059575A1 - Yieldable roof support system - Google Patents
Yieldable roof support systemInfo
- Publication number
- CA2059575A1 CA2059575A1 CA002059575A CA2059575A CA2059575A1 CA 2059575 A1 CA2059575 A1 CA 2059575A1 CA 002059575 A CA002059575 A CA 002059575A CA 2059575 A CA2059575 A CA 2059575A CA 2059575 A1 CA2059575 A1 CA 2059575A1
- Authority
- CA
- Canada
- Prior art keywords
- support
- bar
- threads
- mandrel
- base member
- 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
- 230000002452 interceptive effect Effects 0.000 claims abstract description 5
- 230000000763 evoking effect Effects 0.000 claims abstract description 4
- 230000033001 locomotion Effects 0.000 claims description 19
- 230000000670 limiting effect Effects 0.000 claims description 6
- 235000012489 doughnuts Nutrition 0.000 claims description 5
- 239000004567 concrete Substances 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000003245 coal Substances 0.000 description 2
- VXTWEDPZMSVFEF-UHFFFAOYSA-N pheniprazine Chemical compound NNC(C)CC1=CC=CC=C1 VXTWEDPZMSVFEF-UHFFFAOYSA-N 0.000 description 2
- WWYNJERNGUHSAO-XUDSTZEESA-N (+)-Norgestrel Chemical compound O=C1CC[C@@H]2[C@H]3CC[C@](CC)([C@](CC4)(O)C#C)[C@@H]4[C@@H]3CCC2=C1 WWYNJERNGUHSAO-XUDSTZEESA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 101100410811 Mus musculus Pxt1 gene Proteins 0.000 description 1
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 1
- 235000018936 Vitellaria paradoxa Nutrition 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 230000001228 trophic effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
- E21D15/14—Telescopic props
- E21D15/16—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure
- E21D15/22—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure with member, pin, cross- piece, or the like, ruptured, sheared through, or permanently deformed upon excessive pressure
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)
- Conveying And Assembling Of Building Elements In Situ (AREA)
- Forms Removed On Construction Sites Or Auxiliary Members Thereof (AREA)
- Joining Of Building Structures In Genera (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
YIELDABLE ROOF SUPPORT SYSTEM
A support includes a base member having an open end and a hollow interior, a forcing member having an end extending through the open end of the base member into the hollow interior thereof and having threads thereon and a mandrel or sliding nut capable of engaging the threads of the forcing member at an adjustable position and providing an interfering relationship between the base and forc-ing members as a compressive load is applied there-to. The support is particularly adapted for use in supporting the roof of a mine.
YIELDABLE ROOF SUPPORT SYSTEM
A support includes a base member having an open end and a hollow interior, a forcing member having an end extending through the open end of the base member into the hollow interior thereof and having threads thereon and a mandrel or sliding nut capable of engaging the threads of the forcing member at an adjustable position and providing an interfering relationship between the base and forc-ing members as a compressive load is applied there-to. The support is particularly adapted for use in supporting the roof of a mine.
Description
~ ~ 5 9 ~ 7 a PATENT APPLICATION
~I~LDA~L~ ROOP SUPPO~T S~STEM
Technical Field The present invention rel~tes generally to ~upports, and more particularly to a nupport that yield~ in a controlled fashion in respon~e to an applied load.
Back~round Art There i~ a need in mining operations, particularly in longwall mines, for ~ roof ~upport that yields in a contrQlled fashion in re~ponse ~o roof lo~d~. In the past, mine operators h~ve used po~t-type roof supports in the form of wood timbers and cribbing. The timbers absorb the initial roof lo~d and the cribbing yield~ a~ load i9 applied thereto 80 that cata~trophic failure of the roof ~upport i~ prevented. Th$s type of roof support ~yste~ i~ one attempt to approYi~ate an ideal sy~te~ which would be very stiff to handle the initial load and ye~ have the ability to yield in a controlled f~hion. ~owever, timbers and cribbing pres~nt a fire haz~rd, are expensive and are labor inten~ive. Al~o, timbers and cribb$ng occupy a relati~ly l~rge volume of ~p~ce and oan thu~
interfer~ with ventilation and complicate ~ove~ent of materials and personnel into and out of ~ mine.
A yield~ble steel post ~or use in ~upport-ing a roof of a mine is di~closed in Coal ~a~azine, June 1990, pages 136 and 137. The post includes a ~g~
PATENT APPLICATION
bottom leg telescoped within an upper leg wherein each leg comprises a length of pipe. A tapered expansion ring i9 welded on the lower leg at a desired position and bottom and top plates are welded to the lower nd upper legs and are adapted to engage a floor and a roof, respectively, of a mine. As a compressive load is applied to the post, the expansion ring radially deform3 the upper leg outwardly as the top leg moves relative to the bottom le~-A prior art yieldable roof support uti-lizes an upper slotted leg of hollow pipe tele-scoped within a lower leg also of hollow pipe~ A
wedge is driven into the slot in the upper leg at a de~ired po~ition. The ~edge cause~ the upper leg to have an interference fit with the lower leg at thi~ position. As load is applied to the support, the lower leg i~ radially deformed by the upper section of leg at the location of the wedge.
A urther type of yieldable post is sold by Jennmar Corp. of Pitt burgh, Pennsylvania. Thi~
type of roo~ support includes an upper channel nested within a lower channel and one or more clamps that couple the upper and lower channels 2~ together.
Other types of roof Ruppor~s include con-crete donuts or cribbing and are described in an article appearing in Coal Age, March 1987, pages 30-33.
None of the foregoing post-type roof sup-port~ has been found to be entirely satisfactory in terms of expense, ease of manufacture and a ~embly and qupport capability.
2 ~ 7 ~ ~AT~NT APPL_CAT-ON
In addition to post-type supports, anchor-type yieldable roof supports for tunnels and the like have been designed wherein a supporting rod extending through the surface of the rock into the tunnel includes a deformation member carried on one end of the rod in axial alignment with a steel tube. When the rod is placed in tension, the deformation member is deflected within the steel tube, thereby deforming the tube radially outwardly 1~ and permitting limited movement of the rod. Such a design is shown in Austrian Patent 378,823.
West German published patent specification 33 14 858 Al discloses a yieldable roof support including a rod having a series of stepp~d portions separated by tapered portions on one end thereo dispo~ed within a steel tube. The stepped and tapered sections deform the steel tube radially outwardly when the rod i placed in tension.
Summary of the Invention A yieldable support for a compressive load is capable of deflecting in a controlled fashion as a load i~ applied thereto and is readily adaptable to many different load conditions.
More particularly, a support comprises a base member having an open end and a hollow interi-or, a forcing member having threads thereon and an end extending through the open end of the ba~e member into the hollow interior thereof and means c~pable of engaging the threads of the forcing member at an adjustable position for providing an interfering relationship between the base and ~orc-?A T ENT Ai?pr CAT rON
2~ 7~ 30055 ing members as a compressive load is applied there-to.
Preferably, according to one aspect o~ the present invention, the providing means comprises a tapered mandrel having a threaded bore therethrough in engagement with the threads on the forcing mem-ber. Also p~eferably, the mandrel and the base member are circular in cross-section, the base member has an inner diameter of a first size throughout its length and the mandrel has an outer diameter of a second size less than the first size at one end thereof and a third size greater than the fir~t size at another end thereof. Purther in accordance with the preferred embodiment, the outer diameter of the mandrel increases linearly from the second size to the third size over a portion of itq length.
If desired, means may be carried by the forcing member and di~posed within the base member for centering the forcing mem'car a~ relative move-ment occurs between the members in response toapplication of load thereto. In accordance with thi~ aspect of the present invention, the centering means preferably comprises a cylindrical nut di~-posed on the ends of the forcing member.
Still further in accordance with thisaspect of the present invention, the forcing member preferably comprises a threaded bar and the base member co~prises a pipe which is radially expanded by the forcing member during relative movement of the members.
PATENT APPL~CATrON
~0~9~7~
In accordance with a further as?ect of the present invention, the providing means comprises a sliding nut and the base member has an inner diame-ter of a first size and the sliding nut has an outer diameter of a second size larger than the first size. Preferably, the sliding nut includes a bore therethrough having threads in engagement with the forcing member threads wherein the forcin~
member threads have a first shear strength and the bore threads have a second shear strength greater than the first shear strength so that the bore threads shear off the forcing member threads as load is applied to the members.
Preferably, means are carried by the forc-ing member and disposed within the base member for centering the fosclng member as relative movementoccurs between the members in response to applica-tion of load thereto. In accordance with this aspect of the present invention, the sliding nut and the end of the base member are complementarily shaped to ascist in centering of the forcing mem-ber.
Further, means may be provided for limit-ing relative movement of the members wherein the ~5 limiting means compri~es a nut carried by the forc-ing member.
The support of the present invention is simple in design and effec~ive to yieldably support compre~sive loads. Also, the length thereof may be easîly adjusted so that mine roofs of differing heights can be accommodated.
?A~NT A~PLrcAT ON
- 6 - 20~7~
Brief Descri~tion of the Drawings Figure 1 comprises an elevational view, partly in section, of a support according to the present invention before application of load there-to;
Figure 2 comprises a view similar toFigure l of the support of the present invention after application of load thereto;
Figure 3 comprises a sectional view of the base member of Figures l and 2;
Figure 4 comprises a plan view of the base member;
Figure S comprises a sectional view of the top plate of ~igures l and 2, Figure 6 comprises a bottom view of the top plate of Figure 7;
Figure 7 comprises a partial sectional view of the mandrel of Figures l and 2;
Figure 8 comprise a plan view of the mandrel;
Figure 9 comprises a partial sectional view of the cylindrical nut of Figures l and 2;
Figure lQ comprises a plan view of the cylindrical nut;
Figure 11 comprises a view similar to Figure l of a further embodiment of the present invention;
Figure 12 comprises a fragmentary eleva-tional view, partly in section, of a modification of the embodiment of Figure ll; and Figure 13 comprises an elevational view of yet another embodiment of the present invention.
PATENT APPL'CATION
_ 7 _ 2 ~ 7 ~
De~cription of the Preferred ~bodiments ~ eferring now to Figure 1, a qupport 10 for supporting a compressive load, such as a roof of a mine, includes a base member 12 having an open 5 end 14 and a hollow interior 16 and a forcing mem-ber 18 in the form of a bar having a series of threads 20 thereabout wherein a first end 22 of the bar extends through the first end 14 of the base member 12 into the hollow interior 16.
Referring now to Figures 3 and ~, the base member 12 may comprise a section of ordinary pipe. In one example of the present invention adapted to support a particular roof load, the base member 12 comprises seamless or butt welded carbon steel pipe constructed in accordance with one or more oF A5TM standards A53, A106 and A120, Schedule 40. Welded to a second end 24 of the base member 12 is a 3teel bottom plate 26 which is adapted to rest on a floor of a mine.
Referring now to Figures 5 and 6, a top plate 28 i5 welded to a hexagonal lock nut 30 which has a series of female threads 32 surrounding a bore 34. The female thread~ 32 accept the threads 20 of the bar 18 located at a second end 36 there-of. The top plate 28 is adapted to engage a roofof a mine.
It should be noted that the bottom plate 26, the top plate 28 and the lock nut 30 are optional in the sense that the base member 12 and bar 18 may be secured to a floor and roof of a mine or other structures, such as a truss, by different means, if desired.
?AT~NT .~:'PL ~CAT -ON
- 8 - 20~9~7~
Referring again to Fi~ure 1, means in the form of a mandrel 40 is capable of engaging the threads 20 of the bar 18 at an adjustable position and provides an interfering relationship between the base member 12 and the bar 18 as a compressive load applied thereto. More specifically, and with reference to Figures 7 and 8, the mandrel 40 includes a bore 42 therethrough having ~emale threads 44 disposed thereabout which are sized to accept the threads 20 of the bar 18. The mandrel is preferably circular in cross-section and includes a first end 46 of a first size or dia-meter, a second end 48 of a second size or diameter and an intermediate portion 50. Preferably, the diameter of the intermediate portion 50 increases linearly (i.e. uniformly) from the first diameter 46 to the second diameter 48, although the diameter `may increase in other than a linear fashion, if desired. The mandrel 40 thus includes an outer surface 52 which is tapered and forms a certain angle with respect to a longitudinal axis 54 of the mandrel 40.
If desired, flat surfaces 55 may be pro-vided on the mandrel 40. The flat surfaces 55 afford engagement of the mandrel 40 by a tool (not shown~ so that the mandrel 40 may be turned to permit the poqition of the mandrel 40 on the bar 18 to be adiusted. This, in turn, permits the height o~ the support 10 to be adjustably variable ~o that the support 10 can be used to support mine roofR of differing heights.
~ATENT APPL-CA~ION
9 2~g~7~
Disposed on the first end 22 of the rod 18 is means in the form of a cylindrieal nut 60 for centering the bar 18 as relative movement between the bar and pipe occurs in response to the applica-S tion of compressive load thereto. The cylindricalnut 60 is fabricated of any suitable material, such as metal or plastic, and is shown in greater detail in Figures 9 and 10. The nut 60 includes an inte-rior bore 62 having female threads 64 therein adapted to engage the threads 20 on the bar 18.
rn the preferred embodiment, the mandrel 40 is fabricated of ductile iron GR 80-55-06 manu-factured to ASTM standard A536-80 BHM 187/255. The rod 18 is No. 18 THREADBAR~ sold by Dywidag Systems International, U.S.A., Inc., located in Lemont, Illinois, a subsidiary of the assignee of the pres-ent application, although a different size bar could be used, if desired. Also, in one example of the present invention, the various parts have the dimensions indicated in Table A presented below, although it should be noted that the following dimensions are optional and are not to be construed as limiting the ~cope of the present invention (reference letters are indicated in the Figures and all dimension are in inches unless otherwiYe indi-cated).
~ATENT APPLTCAT'ON
lo- 2~5~57~
Table A
Reference Letter Dimension ~ __ _ _ A 36.000*
8 0.500 C ~ . 000 D 3.548 E 6.000 F
G 2.000 6.000 I 3.250 J 4.535 K 2.248 L 5.000 M 1.000 ~ 3.000 0 1.000 p 3.423 Q 10.5 degrees R 3.423 S 0.63 T 0.125 U
V 2.248 ~he lengths of the base member 12 and the bar 18 depend upon the height of the mine ~oof above the floor and vary with the particular installation.
PATENT Appr _CA~'ON
20~5~
Referring again to Figures 1 and 2, before the bar 18 and base member are subjected to com-pressive loading, the bar 18 is inserted into the base member 12 such that the cylindrical nut 60 and S a portion of the mandrel 40 are disposed within the interior 16 of the base member 12. As noted pre-viously, the height of the support 10 is adjusted by turning the mandrel 40 so that the support 10 is disposed between and in contact with the roo~ and 100r of a mine. As a compressive load is applied to the bar 18 and the base member 12, celative movement occurs between the bar 18 and the base member 12 in the axial direction. Thls axial move-ment causes radial deformation of the base member 12 due to the interference fit of the mandrel 40.
The radial deformation permits the support 10 to yield in response to applied loads in a controlled fashion so that catastrophic failure of the support 10 is preven~ed. During relative movement of the rod 18 and the base member 12, the cylindrical nut 60 acts to keep the rod 18 centered within the base member 12. As can be seen with reference to ~igure 1, the height of the support 10 prior to relative movement of the rod 18 and the base member 12 may be adjusted by rotating the mandrel 40 on the threads 20 to thereby change the elevation there-of. The support 10 may thus be readily adapted for diferent roof heights a~ needed.
The material for the base member 12 and relative dimension~ of the mandrel 40 and the base member 12 are selected so that the maximum load carrying eapacity of the support 10 i8 less than ~?A~ T A2Pr CATrOt`l 30055 20~575 the calculated buckling capacity thereof by a desired safety margin. Also, the angle Q shown in the drawings may be any angle that provides the desired load handling capacity, although angles S within a range between 7 and 15 degrees have been ~ound to result in a most advantageous arrange-ment.
~ hen a compressive load is first applied, the mandrel 40 trasmits a radially outward ~orce against the walls of the base member 12. The walls of the base member 12 deform as increasing load is applied until the yielding limit of the base member 12 is reached. Thereafter, the support 10 yields and provides a substantially constant and continu-ou~ upward force resisting the applied load untilthe full travel limit of the support 10 i5 reach ed.
Pigure ll illustrates an alternative embodiment of the present invention. Elements common between Figure~ l-lO and ll are assigned like reference numerals. As with the previous embodiment, the rod 18 extends into the hollow interior 16 of the base member 12. In this embodi-ment, the base member 12 must have a load carrying capacity in exces3 of the breaking load limit of the bar 18. Al~o, the threaded rod is received within a threaded bore of a sliding nut 70. The ~liding nut 70 includes a reduced diameter pcrtion 72 which is received within the first end 14 of the base member 12 and a second enlarged diameter por-tion 74 which is disposed atop the end 14 and whichhas a diameter at least equal to the inner diameter ?ATENT A~PLlCAT-5N
- 13 - 2~ 7~
of the base member 12. The first end of the base member 12 and the sliding nut 70 are complementar-lly shaped to assist in centering of the rod 18 within the base member 12 during relative movement thereof.
Referring to Figure 12, the sliding nut 70 may instead be replaced by a different sliding nut having a rounded lower surface 82 which is received within a cylindrical seat 84 formed on end walls of the base member 12. Again, the sliding nut and the end of 14 of the base member 12 are complementarily shaped to assist in centering of the rod 18 within the base member 12. Each of the ~liding nuts 70, 80 includes female threads 90 which are shaped to engage the threads 20 on the rod 28. Preferably, although not necessarily, and as seen in Figure 12, the threads 20 do not extend continuously about the bar 18. Rather, the threads 20 are discontinuous in the sense that adjacent threads 20 are separated from one another at one or more regions 91 extending axially along the bar 18. The threads 90 have a higher shear strength than the threads 20 so that, a a compressive load is applied to the bar 18 and the ba3e member 12, the threads 30 sequentially shear off individual threads 20. Thi~ shearing permits relative move-ment oÇ the bar 18 and the ba~e member 12 in respon~e to applied load so that the support yields in a co~trolled fashion in response to applied load.
It can be seen that, as with the previous embodimçnt, ylelding is permitted by an interfer-2ATE~T ~PPL-CA~ ON
- 14 - 20~957~
ence fit between relatively movable members so that loads can be supported without catastrophic failure of the support.
More particularly, the supports of Figures ll and 12 resist deflection until a load of a mag-nitude sufficient to shear one of the threads 20 is applied. The upward force resisting the compres-3ive load then drops and thereafter rises until a load magnitude is applied which causes shea~ing of the next thread 20. The resisting force thereafter rises and falls as threads 20 are sheared, allowing the support to yield in a controlled fashion.
If desired, an optional safety nut 100 may be threaded on the rod 18 at an appropriate height to limit relative movement of the bar 18 and the support member 12. The safety nut 100 is designed to carry a load in excess of the breaking load of the bar 18.
It should be noted that projections other than threads may be used to provide the interfer-ence fit between the sliding nut 70 or 80 and the bar 18, if desired. Also, a different complemen-tary fit between the sliding nut 70 or 80 and the base member 12 may be utilized.
~t should be noted that the sliding nut 70 or 80 and the rod 18 may be supported by any other ~tructure having an opening or aperture there-through to permit travel of the rod 18. In any case, the support structure i~ preferably capable of carrying a load in excess of the breaking load limit of the bar 18. Thus, for example, Figure 13 illustrates an alternative embodiment of the pre-?A.-N~ ~??....CA~ '~)N
3005~
- 15 - 20~77 sent invention wherein the support of Figures 11 and 12 may be used together with conventional wooden cribbings or concrete donuts to yieLdably support a load. The embodiment of Figure 13 pro-vides greater resistance against buckling as com-pared with the embodiment of Figures 11 and 12.
More specifically, one or more threaded bars 18 are disposed within one or more sliding nuts 70 or 80 that are in turn disposed atop collars 108. A
series of wooden cribbings or concrete donuts 110 are stacked beneath the bars 18, the sliding nut 70 or 80 and the collars 108 and include aligned aper-tures or bores 112 therein. Disposed atop the bars 18 are top plates 128 secured to the bars 18 by nuts 136 welded thereto.
As a roof load is applied to the bars 18 atop the plates 128, the sliding nuts 70 or 80 shear threads on the bars 18, as before. The bars 18 thus extend into the bores 112 in the cribbings or donuts 110.
The embodiment of Figure 13 has the advan-tage in that only a relatively short length of bar 18 i~ needed and a high yielding path i5 provid-ed.
It should be noted that multiple supports according to the present invention can be used together and joined between a common top plate and bottom plate to form a multiple unit for supporting a compressive load.
Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing ?A'n-NT A?P' _C~3.T 'ON
3005, - 16 -- 20~9~7~
description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out l:he invention. The de-tails of the structure may be varied substantiallywithout departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.
~I~LDA~L~ ROOP SUPPO~T S~STEM
Technical Field The present invention rel~tes generally to ~upports, and more particularly to a nupport that yield~ in a controlled fashion in respon~e to an applied load.
Back~round Art There i~ a need in mining operations, particularly in longwall mines, for ~ roof ~upport that yields in a contrQlled fashion in re~ponse ~o roof lo~d~. In the past, mine operators h~ve used po~t-type roof supports in the form of wood timbers and cribbing. The timbers absorb the initial roof lo~d and the cribbing yield~ a~ load i9 applied thereto 80 that cata~trophic failure of the roof ~upport i~ prevented. Th$s type of roof support ~yste~ i~ one attempt to approYi~ate an ideal sy~te~ which would be very stiff to handle the initial load and ye~ have the ability to yield in a controlled f~hion. ~owever, timbers and cribbing pres~nt a fire haz~rd, are expensive and are labor inten~ive. Al~o, timbers and cribb$ng occupy a relati~ly l~rge volume of ~p~ce and oan thu~
interfer~ with ventilation and complicate ~ove~ent of materials and personnel into and out of ~ mine.
A yield~ble steel post ~or use in ~upport-ing a roof of a mine is di~closed in Coal ~a~azine, June 1990, pages 136 and 137. The post includes a ~g~
PATENT APPLICATION
bottom leg telescoped within an upper leg wherein each leg comprises a length of pipe. A tapered expansion ring i9 welded on the lower leg at a desired position and bottom and top plates are welded to the lower nd upper legs and are adapted to engage a floor and a roof, respectively, of a mine. As a compressive load is applied to the post, the expansion ring radially deform3 the upper leg outwardly as the top leg moves relative to the bottom le~-A prior art yieldable roof support uti-lizes an upper slotted leg of hollow pipe tele-scoped within a lower leg also of hollow pipe~ A
wedge is driven into the slot in the upper leg at a de~ired po~ition. The ~edge cause~ the upper leg to have an interference fit with the lower leg at thi~ position. As load is applied to the support, the lower leg i~ radially deformed by the upper section of leg at the location of the wedge.
A urther type of yieldable post is sold by Jennmar Corp. of Pitt burgh, Pennsylvania. Thi~
type of roo~ support includes an upper channel nested within a lower channel and one or more clamps that couple the upper and lower channels 2~ together.
Other types of roof Ruppor~s include con-crete donuts or cribbing and are described in an article appearing in Coal Age, March 1987, pages 30-33.
None of the foregoing post-type roof sup-port~ has been found to be entirely satisfactory in terms of expense, ease of manufacture and a ~embly and qupport capability.
2 ~ 7 ~ ~AT~NT APPL_CAT-ON
In addition to post-type supports, anchor-type yieldable roof supports for tunnels and the like have been designed wherein a supporting rod extending through the surface of the rock into the tunnel includes a deformation member carried on one end of the rod in axial alignment with a steel tube. When the rod is placed in tension, the deformation member is deflected within the steel tube, thereby deforming the tube radially outwardly 1~ and permitting limited movement of the rod. Such a design is shown in Austrian Patent 378,823.
West German published patent specification 33 14 858 Al discloses a yieldable roof support including a rod having a series of stepp~d portions separated by tapered portions on one end thereo dispo~ed within a steel tube. The stepped and tapered sections deform the steel tube radially outwardly when the rod i placed in tension.
Summary of the Invention A yieldable support for a compressive load is capable of deflecting in a controlled fashion as a load i~ applied thereto and is readily adaptable to many different load conditions.
More particularly, a support comprises a base member having an open end and a hollow interi-or, a forcing member having threads thereon and an end extending through the open end of the ba~e member into the hollow interior thereof and means c~pable of engaging the threads of the forcing member at an adjustable position for providing an interfering relationship between the base and ~orc-?A T ENT Ai?pr CAT rON
2~ 7~ 30055 ing members as a compressive load is applied there-to.
Preferably, according to one aspect o~ the present invention, the providing means comprises a tapered mandrel having a threaded bore therethrough in engagement with the threads on the forcing mem-ber. Also p~eferably, the mandrel and the base member are circular in cross-section, the base member has an inner diameter of a first size throughout its length and the mandrel has an outer diameter of a second size less than the first size at one end thereof and a third size greater than the fir~t size at another end thereof. Purther in accordance with the preferred embodiment, the outer diameter of the mandrel increases linearly from the second size to the third size over a portion of itq length.
If desired, means may be carried by the forcing member and di~posed within the base member for centering the forcing mem'car a~ relative move-ment occurs between the members in response toapplication of load thereto. In accordance with thi~ aspect of the present invention, the centering means preferably comprises a cylindrical nut di~-posed on the ends of the forcing member.
Still further in accordance with thisaspect of the present invention, the forcing member preferably comprises a threaded bar and the base member co~prises a pipe which is radially expanded by the forcing member during relative movement of the members.
PATENT APPL~CATrON
~0~9~7~
In accordance with a further as?ect of the present invention, the providing means comprises a sliding nut and the base member has an inner diame-ter of a first size and the sliding nut has an outer diameter of a second size larger than the first size. Preferably, the sliding nut includes a bore therethrough having threads in engagement with the forcing member threads wherein the forcin~
member threads have a first shear strength and the bore threads have a second shear strength greater than the first shear strength so that the bore threads shear off the forcing member threads as load is applied to the members.
Preferably, means are carried by the forc-ing member and disposed within the base member for centering the fosclng member as relative movementoccurs between the members in response to applica-tion of load thereto. In accordance with this aspect of the present invention, the sliding nut and the end of the base member are complementarily shaped to ascist in centering of the forcing mem-ber.
Further, means may be provided for limit-ing relative movement of the members wherein the ~5 limiting means compri~es a nut carried by the forc-ing member.
The support of the present invention is simple in design and effec~ive to yieldably support compre~sive loads. Also, the length thereof may be easîly adjusted so that mine roofs of differing heights can be accommodated.
?A~NT A~PLrcAT ON
- 6 - 20~7~
Brief Descri~tion of the Drawings Figure 1 comprises an elevational view, partly in section, of a support according to the present invention before application of load there-to;
Figure 2 comprises a view similar toFigure l of the support of the present invention after application of load thereto;
Figure 3 comprises a sectional view of the base member of Figures l and 2;
Figure 4 comprises a plan view of the base member;
Figure S comprises a sectional view of the top plate of ~igures l and 2, Figure 6 comprises a bottom view of the top plate of Figure 7;
Figure 7 comprises a partial sectional view of the mandrel of Figures l and 2;
Figure 8 comprise a plan view of the mandrel;
Figure 9 comprises a partial sectional view of the cylindrical nut of Figures l and 2;
Figure lQ comprises a plan view of the cylindrical nut;
Figure 11 comprises a view similar to Figure l of a further embodiment of the present invention;
Figure 12 comprises a fragmentary eleva-tional view, partly in section, of a modification of the embodiment of Figure ll; and Figure 13 comprises an elevational view of yet another embodiment of the present invention.
PATENT APPL'CATION
_ 7 _ 2 ~ 7 ~
De~cription of the Preferred ~bodiments ~ eferring now to Figure 1, a qupport 10 for supporting a compressive load, such as a roof of a mine, includes a base member 12 having an open 5 end 14 and a hollow interior 16 and a forcing mem-ber 18 in the form of a bar having a series of threads 20 thereabout wherein a first end 22 of the bar extends through the first end 14 of the base member 12 into the hollow interior 16.
Referring now to Figures 3 and ~, the base member 12 may comprise a section of ordinary pipe. In one example of the present invention adapted to support a particular roof load, the base member 12 comprises seamless or butt welded carbon steel pipe constructed in accordance with one or more oF A5TM standards A53, A106 and A120, Schedule 40. Welded to a second end 24 of the base member 12 is a 3teel bottom plate 26 which is adapted to rest on a floor of a mine.
Referring now to Figures 5 and 6, a top plate 28 i5 welded to a hexagonal lock nut 30 which has a series of female threads 32 surrounding a bore 34. The female thread~ 32 accept the threads 20 of the bar 18 located at a second end 36 there-of. The top plate 28 is adapted to engage a roofof a mine.
It should be noted that the bottom plate 26, the top plate 28 and the lock nut 30 are optional in the sense that the base member 12 and bar 18 may be secured to a floor and roof of a mine or other structures, such as a truss, by different means, if desired.
?AT~NT .~:'PL ~CAT -ON
- 8 - 20~9~7~
Referring again to Fi~ure 1, means in the form of a mandrel 40 is capable of engaging the threads 20 of the bar 18 at an adjustable position and provides an interfering relationship between the base member 12 and the bar 18 as a compressive load applied thereto. More specifically, and with reference to Figures 7 and 8, the mandrel 40 includes a bore 42 therethrough having ~emale threads 44 disposed thereabout which are sized to accept the threads 20 of the bar 18. The mandrel is preferably circular in cross-section and includes a first end 46 of a first size or dia-meter, a second end 48 of a second size or diameter and an intermediate portion 50. Preferably, the diameter of the intermediate portion 50 increases linearly (i.e. uniformly) from the first diameter 46 to the second diameter 48, although the diameter `may increase in other than a linear fashion, if desired. The mandrel 40 thus includes an outer surface 52 which is tapered and forms a certain angle with respect to a longitudinal axis 54 of the mandrel 40.
If desired, flat surfaces 55 may be pro-vided on the mandrel 40. The flat surfaces 55 afford engagement of the mandrel 40 by a tool (not shown~ so that the mandrel 40 may be turned to permit the poqition of the mandrel 40 on the bar 18 to be adiusted. This, in turn, permits the height o~ the support 10 to be adjustably variable ~o that the support 10 can be used to support mine roofR of differing heights.
~ATENT APPL-CA~ION
9 2~g~7~
Disposed on the first end 22 of the rod 18 is means in the form of a cylindrieal nut 60 for centering the bar 18 as relative movement between the bar and pipe occurs in response to the applica-S tion of compressive load thereto. The cylindricalnut 60 is fabricated of any suitable material, such as metal or plastic, and is shown in greater detail in Figures 9 and 10. The nut 60 includes an inte-rior bore 62 having female threads 64 therein adapted to engage the threads 20 on the bar 18.
rn the preferred embodiment, the mandrel 40 is fabricated of ductile iron GR 80-55-06 manu-factured to ASTM standard A536-80 BHM 187/255. The rod 18 is No. 18 THREADBAR~ sold by Dywidag Systems International, U.S.A., Inc., located in Lemont, Illinois, a subsidiary of the assignee of the pres-ent application, although a different size bar could be used, if desired. Also, in one example of the present invention, the various parts have the dimensions indicated in Table A presented below, although it should be noted that the following dimensions are optional and are not to be construed as limiting the ~cope of the present invention (reference letters are indicated in the Figures and all dimension are in inches unless otherwiYe indi-cated).
~ATENT APPLTCAT'ON
lo- 2~5~57~
Table A
Reference Letter Dimension ~ __ _ _ A 36.000*
8 0.500 C ~ . 000 D 3.548 E 6.000 F
G 2.000 6.000 I 3.250 J 4.535 K 2.248 L 5.000 M 1.000 ~ 3.000 0 1.000 p 3.423 Q 10.5 degrees R 3.423 S 0.63 T 0.125 U
V 2.248 ~he lengths of the base member 12 and the bar 18 depend upon the height of the mine ~oof above the floor and vary with the particular installation.
PATENT Appr _CA~'ON
20~5~
Referring again to Figures 1 and 2, before the bar 18 and base member are subjected to com-pressive loading, the bar 18 is inserted into the base member 12 such that the cylindrical nut 60 and S a portion of the mandrel 40 are disposed within the interior 16 of the base member 12. As noted pre-viously, the height of the support 10 is adjusted by turning the mandrel 40 so that the support 10 is disposed between and in contact with the roo~ and 100r of a mine. As a compressive load is applied to the bar 18 and the base member 12, celative movement occurs between the bar 18 and the base member 12 in the axial direction. Thls axial move-ment causes radial deformation of the base member 12 due to the interference fit of the mandrel 40.
The radial deformation permits the support 10 to yield in response to applied loads in a controlled fashion so that catastrophic failure of the support 10 is preven~ed. During relative movement of the rod 18 and the base member 12, the cylindrical nut 60 acts to keep the rod 18 centered within the base member 12. As can be seen with reference to ~igure 1, the height of the support 10 prior to relative movement of the rod 18 and the base member 12 may be adjusted by rotating the mandrel 40 on the threads 20 to thereby change the elevation there-of. The support 10 may thus be readily adapted for diferent roof heights a~ needed.
The material for the base member 12 and relative dimension~ of the mandrel 40 and the base member 12 are selected so that the maximum load carrying eapacity of the support 10 i8 less than ~?A~ T A2Pr CATrOt`l 30055 20~575 the calculated buckling capacity thereof by a desired safety margin. Also, the angle Q shown in the drawings may be any angle that provides the desired load handling capacity, although angles S within a range between 7 and 15 degrees have been ~ound to result in a most advantageous arrange-ment.
~ hen a compressive load is first applied, the mandrel 40 trasmits a radially outward ~orce against the walls of the base member 12. The walls of the base member 12 deform as increasing load is applied until the yielding limit of the base member 12 is reached. Thereafter, the support 10 yields and provides a substantially constant and continu-ou~ upward force resisting the applied load untilthe full travel limit of the support 10 i5 reach ed.
Pigure ll illustrates an alternative embodiment of the present invention. Elements common between Figure~ l-lO and ll are assigned like reference numerals. As with the previous embodiment, the rod 18 extends into the hollow interior 16 of the base member 12. In this embodi-ment, the base member 12 must have a load carrying capacity in exces3 of the breaking load limit of the bar 18. Al~o, the threaded rod is received within a threaded bore of a sliding nut 70. The ~liding nut 70 includes a reduced diameter pcrtion 72 which is received within the first end 14 of the base member 12 and a second enlarged diameter por-tion 74 which is disposed atop the end 14 and whichhas a diameter at least equal to the inner diameter ?ATENT A~PLlCAT-5N
- 13 - 2~ 7~
of the base member 12. The first end of the base member 12 and the sliding nut 70 are complementar-lly shaped to assist in centering of the rod 18 within the base member 12 during relative movement thereof.
Referring to Figure 12, the sliding nut 70 may instead be replaced by a different sliding nut having a rounded lower surface 82 which is received within a cylindrical seat 84 formed on end walls of the base member 12. Again, the sliding nut and the end of 14 of the base member 12 are complementarily shaped to assist in centering of the rod 18 within the base member 12. Each of the ~liding nuts 70, 80 includes female threads 90 which are shaped to engage the threads 20 on the rod 28. Preferably, although not necessarily, and as seen in Figure 12, the threads 20 do not extend continuously about the bar 18. Rather, the threads 20 are discontinuous in the sense that adjacent threads 20 are separated from one another at one or more regions 91 extending axially along the bar 18. The threads 90 have a higher shear strength than the threads 20 so that, a a compressive load is applied to the bar 18 and the ba3e member 12, the threads 30 sequentially shear off individual threads 20. Thi~ shearing permits relative move-ment oÇ the bar 18 and the ba~e member 12 in respon~e to applied load so that the support yields in a co~trolled fashion in response to applied load.
It can be seen that, as with the previous embodimçnt, ylelding is permitted by an interfer-2ATE~T ~PPL-CA~ ON
- 14 - 20~957~
ence fit between relatively movable members so that loads can be supported without catastrophic failure of the support.
More particularly, the supports of Figures ll and 12 resist deflection until a load of a mag-nitude sufficient to shear one of the threads 20 is applied. The upward force resisting the compres-3ive load then drops and thereafter rises until a load magnitude is applied which causes shea~ing of the next thread 20. The resisting force thereafter rises and falls as threads 20 are sheared, allowing the support to yield in a controlled fashion.
If desired, an optional safety nut 100 may be threaded on the rod 18 at an appropriate height to limit relative movement of the bar 18 and the support member 12. The safety nut 100 is designed to carry a load in excess of the breaking load of the bar 18.
It should be noted that projections other than threads may be used to provide the interfer-ence fit between the sliding nut 70 or 80 and the bar 18, if desired. Also, a different complemen-tary fit between the sliding nut 70 or 80 and the base member 12 may be utilized.
~t should be noted that the sliding nut 70 or 80 and the rod 18 may be supported by any other ~tructure having an opening or aperture there-through to permit travel of the rod 18. In any case, the support structure i~ preferably capable of carrying a load in excess of the breaking load limit of the bar 18. Thus, for example, Figure 13 illustrates an alternative embodiment of the pre-?A.-N~ ~??....CA~ '~)N
3005~
- 15 - 20~77 sent invention wherein the support of Figures 11 and 12 may be used together with conventional wooden cribbings or concrete donuts to yieLdably support a load. The embodiment of Figure 13 pro-vides greater resistance against buckling as com-pared with the embodiment of Figures 11 and 12.
More specifically, one or more threaded bars 18 are disposed within one or more sliding nuts 70 or 80 that are in turn disposed atop collars 108. A
series of wooden cribbings or concrete donuts 110 are stacked beneath the bars 18, the sliding nut 70 or 80 and the collars 108 and include aligned aper-tures or bores 112 therein. Disposed atop the bars 18 are top plates 128 secured to the bars 18 by nuts 136 welded thereto.
As a roof load is applied to the bars 18 atop the plates 128, the sliding nuts 70 or 80 shear threads on the bars 18, as before. The bars 18 thus extend into the bores 112 in the cribbings or donuts 110.
The embodiment of Figure 13 has the advan-tage in that only a relatively short length of bar 18 i~ needed and a high yielding path i5 provid-ed.
It should be noted that multiple supports according to the present invention can be used together and joined between a common top plate and bottom plate to form a multiple unit for supporting a compressive load.
Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing ?A'n-NT A?P' _C~3.T 'ON
3005, - 16 -- 20~9~7~
description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out l:he invention. The de-tails of the structure may be varied substantiallywithout departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.
Claims (30)
1. A support, comprising:
a base member having an open end and a hollow interior;
a forcing member having an end extending through the open end of the base member into the hollow interior thereof and having threads thereon;
and means capable of engaging the threads of the forcing member at an adjustable position for providing an interfering relationship between the base and forcing members as a compressive load is applied thereto.
a base member having an open end and a hollow interior;
a forcing member having an end extending through the open end of the base member into the hollow interior thereof and having threads thereon;
and means capable of engaging the threads of the forcing member at an adjustable position for providing an interfering relationship between the base and forcing members as a compressive load is applied thereto.
2. The support of claim 1, wherein the providing means comprises a tapered mandrel having a threaded bore therethrough in engagement with the threads on the forcing member.
3. The support of claim 2, wherein the mandrel and the base member are circular in cross-section, the base member has an inner diameter of a first size throughout its length and the mandrel has an outer diameter of a second size less than the first size at another end thereof.
4. The support of claim 3, wherein the outer diameter of the mandrel increases linearly from the second size to the third size over a por-tion of its length.
PATENT APPLICATION
PATENT APPLICATION
5. The support of claim 1, further including means carried by the forcing member and disposed within the base member for centering the forcing member as relative movement occurs between the members in response to application of load thereto.
6. The support of claim 5, wherein the centering means comprises a cylindrical nut dis-posed on the threads of the forcing member.
7. The support of claim 1, wherein the forcing member comprises a threaded bar.
8. The support of claim 1, wherein the base member comprises a pipe which is radially expanded by the forcing member during relative movement of the members.
9. The support of claim 1, wherein the providing means comprises a sliding nut.
10. The support of claim 9, wherein the rod has a breaking load limit and the base member has an inner diameter of a first size and has a load carrying capacity less than the breaking load limit of the rod and the sliding nut has an outer diameter of a second size larger than the first size.
PATENT APPLICATION
PATENT APPLICATION
11. The support of claim 10, wherein the sliding nut includes a bore therethrough having threads in engagement with the forcing member threads wherein the forcing member threads have a first shear strength and the bore threads have a second shear strength greater than the first shear strength so that the bore threads shear off forcing member threads as load is applied to the members.
12. The support of claim 11, further including means carried by the forcing member and disposed within the base member for centering the forcing member as relative movement occurs between the members in response to application of load thereto.
13. The support of claim 12, wherein the sliding nut and the end of the base member are complementarily shaped to assist in centering of the forcing member.
14. The support of claim 13, wherein the limiting means comprises a nut carried by the forc-ing member.
PATENT APPLICATION
PATENT APPLICATION
15. A roof support for a mine, compris-ing:
a pipe having first and second ends and walls defining a channel therethrough of circular cross-section having a substantially constant dia-meter over its length.
a bar having first and second ends and threads about an outer periphery thereof;
a mandrel having a threaded bore there-through in engagement with the threads on the bar whereby the mandrel may be positioned at a desired point on the bar by turning the mandrel relative to the bar, the mandrel further including and outer surface of first diameter smaller than the substan-tially constant diameter at a first end thereof and of second diameter larger than the substantially constant diameter at a second end thereof opposite the first end;
wherein the first end of the bar extends through the first end of the pipe and the mandrel is disposed at least partially within the pipe channel such that the outer surface thereof is in interfering contact with the walls of the pipe; and top and bottom plates disposed on the second ends of the bar and pipe, respectively, and adapted to engage a roof and a floor, respectively, of a mine.
PATENT APPLICATION
a pipe having first and second ends and walls defining a channel therethrough of circular cross-section having a substantially constant dia-meter over its length.
a bar having first and second ends and threads about an outer periphery thereof;
a mandrel having a threaded bore there-through in engagement with the threads on the bar whereby the mandrel may be positioned at a desired point on the bar by turning the mandrel relative to the bar, the mandrel further including and outer surface of first diameter smaller than the substan-tially constant diameter at a first end thereof and of second diameter larger than the substantially constant diameter at a second end thereof opposite the first end;
wherein the first end of the bar extends through the first end of the pipe and the mandrel is disposed at least partially within the pipe channel such that the outer surface thereof is in interfering contact with the walls of the pipe; and top and bottom plates disposed on the second ends of the bar and pipe, respectively, and adapted to engage a roof and a floor, respectively, of a mine.
PATENT APPLICATION
16. The roof support of claim 15, further including a cylindrical nut carried by the bar and disposed within the pipe channel for centering the bar as relative movement occurs between the bar and pipe in response to application of load thereto.
17. The roof support of claim 15, wherein the mandrel includes a longitudinal axis and the mandrel outer surface includes an intermediate tapered portion of uniformly increasing diameter and disposed at a certain angle with respect to the longitudinal axis.
18. The roof support of claim 17, wherein the certain angle is within a range between 7 and 15 degrees.
19. The roof support of claim 18, wherein the certain angle is equal to 10.5 degrees.
20. The roof support of claim 15, wherein the substantially constant diameter is equal to 3.548 inches and the second diameter is equal to 4.535 inches.
21. The roof support of claim 20, wherein the first diameter is equal to 3.423 inches.
PATENT APPLICATION
PATENT APPLICATION
22. A roof support for a mine, compris-ing:
a support structure having a support sur-face and an aperture therethrough;
a bar having first and second ends and a projection about an outer periphery thereof, the projection having a first shear strength;
a sliding nut having a bore therethrough and having a portion in engagement with the pro-jection on the bar whereby the portion of the sliding nut has a second shear strength greater than the first shear strength;
wherein the first end of the bar extends into the aperture and the sliding nut is disposed in contact with the support surface of the support structure; and top and bottom plates disposed on the second ends of the bar and support structure, respectively, and adapted to engage a roof and a floor, respectively, of a mine.
a support structure having a support sur-face and an aperture therethrough;
a bar having first and second ends and a projection about an outer periphery thereof, the projection having a first shear strength;
a sliding nut having a bore therethrough and having a portion in engagement with the pro-jection on the bar whereby the portion of the sliding nut has a second shear strength greater than the first shear strength;
wherein the first end of the bar extends into the aperture and the sliding nut is disposed in contact with the support surface of the support structure; and top and bottom plates disposed on the second ends of the bar and support structure, respectively, and adapted to engage a roof and a floor, respectively, of a mine.
23. The roof support of claim 22, wherein the support structure comprises a pipe.
24. The roof support of claim 23, further including a cylindrical nut carried by the bar and disposed within the channel for centering the bar as relative movement occurs between the bar and pipe.
PATENT APPLICATION
PATENT APPLICATION
25. The roof support of claim 22, wherein the support structure comprises wooden cribbings.
26. The roof support of claim 22, wherein the support structure comprises concrete donuts.
27. The roof support of claim 22, wherein the projection on the bar comprises a series of threads and wherein the threads are sheared off the bar as relative movement occurs between the bar and support structure system in response to application of a compressive load thereto.
28. The support claim 22, wherein the sliding nut and the support surface are complemen-tarily shaped to assist in centering of the bar.
29. The support claim 22, further includ-ing means for limiting relative movement of the bar and support structure.
30. The support of claim 29, wherein the limiting means comprises a nut carried by the bar.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64500091A | 1991-01-22 | 1991-01-22 | |
| US645,000 | 1991-01-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2059575A1 true CA2059575A1 (en) | 1992-07-23 |
Family
ID=24587241
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002059575A Abandoned CA2059575A1 (en) | 1991-01-22 | 1992-01-16 | Yieldable roof support system |
Country Status (6)
| Country | Link |
|---|---|
| AU (1) | AU651653B2 (en) |
| CA (1) | CA2059575A1 (en) |
| FR (1) | FR2671829A1 (en) |
| GB (1) | GB2252114A (en) |
| PL (1) | PL293251A1 (en) |
| ZA (1) | ZA92159B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USD649434S1 (en) | 2010-02-08 | 2011-11-29 | Thomas & Betts International, Inc. | Multi-purpose roof-top support |
| US9677690B2 (en) | 2010-02-08 | 2017-06-13 | Thomas & Betts International, Llc | Multi-purpose roof-top support |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5314161A (en) * | 1992-05-29 | 1994-05-24 | Bochumer Eisenhutte Heintzmann Gmbh & Co. Kg | Mine prop |
| GB2302578B (en) * | 1995-06-23 | 1999-02-17 | R G Manufacturing Ltd | Nudge bar and energy absorbing device |
| RU2155266C2 (en) * | 1997-02-07 | 2000-08-27 | Атрушкевич Аркадий Анисимович | Temporary support prop |
| CN104179366B (en) * | 2014-08-21 | 2016-04-27 | 四川金锋建设有限公司 | Recessed device prevented by large span thin plate |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE875335C (en) * | 1950-07-19 | 1953-04-30 | Walter Murmann | Flexible multi-part extension stamp |
| AU542884B2 (en) * | 1980-07-31 | 1985-03-21 | Dipl.Ing. Dr. Mont. Franz Powondra | Resilient yieldable device |
| AT376009B (en) * | 1982-12-13 | 1984-10-10 | Powondra Franz Dipl Ing Dr | METHOD FOR OBTAINING A FLEXIBLE CONNECTION BETWEEN A METALLIC ROD-SHAPED BODY AND A BRACKET THROUGH IT |
| DE3503012A1 (en) * | 1985-01-30 | 1986-07-31 | Dyckerhoff & Widmann AG, 8000 München | TENSIONING DEVICE FOR THE TIE LINK OF AN ANCHOR, ESPECIALLY A ROCK ANCHOR |
-
1992
- 1992-01-07 AU AU10083/92A patent/AU651653B2/en not_active Ceased
- 1992-01-09 ZA ZA92159A patent/ZA92159B/en unknown
- 1992-01-14 GB GB9200725A patent/GB2252114A/en not_active Withdrawn
- 1992-01-16 CA CA002059575A patent/CA2059575A1/en not_active Abandoned
- 1992-01-21 FR FR9200573A patent/FR2671829A1/en active Pending
- 1992-01-22 PL PL29325192A patent/PL293251A1/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USD649434S1 (en) | 2010-02-08 | 2011-11-29 | Thomas & Betts International, Inc. | Multi-purpose roof-top support |
| US9677690B2 (en) | 2010-02-08 | 2017-06-13 | Thomas & Betts International, Llc | Multi-purpose roof-top support |
Also Published As
| Publication number | Publication date |
|---|---|
| AU651653B2 (en) | 1994-07-28 |
| FR2671829A1 (en) | 1992-07-24 |
| ZA92159B (en) | 1992-10-28 |
| PL293251A1 (en) | 1992-10-05 |
| GB9200725D0 (en) | 1992-03-11 |
| GB2252114A (en) | 1992-07-29 |
| AU1008392A (en) | 1992-07-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |