GB2219816A - Reinforcement means, method and apparatus for reinforcing substrata - Google Patents

Abstract

A method of reinforcing substrata e.g. in mines or buildings using a novel reinforcement bar and apparatus is described in which a reinforcement bar (10) is secured in a hole (14) in substrata e.g. by known curing resin. An end portion (18) of the bar projects through a hole (20) in a reinforcement plate (12) which is deformed to grip the bar (10) and to urge the plate (12) firmly against the substrata (16) by a presser member (24) of the tool. Head (56) of the bar (10) is gripped by complementary half collets (48, 50) which also grip a head (42) of the piston rod (40) of the setting apparatus, the half collets (48, 50) being retained in gripping engagement by the presser member (24) which is in the form of a sleeve (44). When the reinforcement plate is set in position, the head (56) is detached from the bar (10) under the applied load thus indicating that the reinforcement is adequately loaded. <IMAGE>

Description

REINFORCEMENT MEONS, METHOD AND APPARATUS FOR REINFORCING SUBSTRATA This invention is concerned with reinforcement means and a method of and apparatus for installing reinforcement means for ! reinforcing substrata, for example mine roof strata or concrete structures.

Both the mining industry and the civil engineering industry utilise reinforcement steel bars, the mining industry to reinforce roof or wall strata in mines whilst the civil engineering industry use such bars to reinforce concrete structures, in addition to the -metal reinforcement often incorporated in concrete structures during their initial casting.

One type of reinforcement means currently in use comprises a hardened steel bar which is inserted into a hole in the substrata to be reinforced, a curing resin having been previously inserted into the hole; the steel bar is then rotates to thoroughly mix the resin which is allowed to cure and lock the steel bar in position. The bars are commonly rotated using prevailing torque nuts to provide the rotating torque necessary to mix the resin, the nuts after the resin has hardened being run up a screw thread on an exposed end portion of the bar to tighten it to the surface of the substrata to be reinforced via a washer plate.The nuts used are relatively expensive and, furthermore, some of the air operated drilling machines in use in mines do not develop sufficient torque to overcome the prevailing torque of the nut and thus cannot be used to tighten the nut, therefore requiring manual tightening which is more time consuming and thus costly.

In the past, use has been made of steel reinforcement bars which has been through-hardened.

However, in civil engineering, a type of reinforcement bar is now acceptable which has a hardened skin and A softer core. This type of bar can be more difficult to skim prior to threading as well as being somewhat weaker at the thread than the through-hardened counterpart.

However, it is considerably less expensive than through-hardened bar.

The applicants have now discovered a method of installing reinforcement means, includiny a novel reinforcement bar, which is simple to use and which overcomes some of the problems which have been encountered with the previously known methods.

In one aspect the invention provides a method of installing relnrorcement means comprising a reinforcerent bar and support means for reinrorcing substrata comprising securing a reinforcement oar in a bole in the substrata with an end portion projecting therPfroa and project through a hole in the support means, and deforming the support means bounding the hole into gripping engagement with the bar with the support means in supporting engagement with a surface of the substrata.

A suitable support means is a generally flat reinforcement plate.

In a preferred method in accordance with the invention the projecting end portion of the bar is gripped by a suitable tool and a presser member of the tool is pressed into engagement with the plate to urge the plate firmly into engagement with said surface and to deform the reinforcement plate. Preferably the projecting portion of the bar has a head to provide means by which the bar can be gripped by the tool.

Preferably, in a method in accordance with the invention using a headed bar, a weakened portion of the bar between the head and the remainder of the bar is arranged to break when the load applied reaches a pre selected level sufficient that the force applied to deform the plate into gripping engagement with the bar will have been sufficient to achieve a pre-defined adequate tripping force. Suitably the weakened portion is provided by a necked portion of the bar.

In a preferred method a curing resin is introduced into the hole in the substrata, the bar is introduced into the hole and rotated to mix the resin and the resin allowed to cure to secure the bar in the hole.

In another aspect the invention may be considered to provide a reinforcement bar suitable for use in reinforcing substrata comprising a first portion adapted to be inserted in a hole in substrata to be reinforced and a second portion adapted to protect from the hole, the second portion comprising a head and a weakened portion by which the head is separated from the remainder of the second portion. Preferably the weakened portion is provided by a necked portion of the bar.

In yet another aspect the invention may be considered to provide a reinforcing assembly suitable for use in reinforcing a substrata comprising a reinforcement bar as set out in the last preceding paragraph and support means on the second portion of the bar the second portion being received in a hole in the support means.

Preferably the support means is a generally flat reinforcement plate having deformable portions bounding the hole. Suitably the deformable portions comprise opposed ears bent out of the plane of the plate towards the head of the bar.

In another aspect the invention may be considered to provide apparatus suitable for use in installing a reinforcement means for reinforcing substrata in which the reinforcement means comprises a bar adapted to be inserted into a hole in the substrata with an end portion projecting and support means on the projecting end portion with the end portion received in a hole in the support means, the apparatus comprising gripping means adapted to grip the projecting end portion of the bar, a presser member adapted to engage a portion of the support means and means for effecting relative movement of the gripping means and the presser member in a direction lengthwise of a bar gripped by the gripping means in the operation of the apparatus whereby to deform the support means bounding the hole into gripping engagement with the projecting end portion of the bar.

Preferably said means for effecting relative movement comprises a hydraulic piston and cylinder arrangement.

Preferably apparatus in accordance with the invention is adapter to be rotated, whilst a bar is gripped oy the yripping means, thus to rotate tbe bar about an axis extending lengthwise of the bar.

preferred apparatus in accordance with the Invent Ion comprises gripping means for gripping a headed portion provided at the extremity of the projecting end portion.

Preferably the gripping means comprises complementary half collets adapted to b slidingly received in a sleeve which provides the presser member. The collets encompass and grip the headed portion of the bar when assembled in the sleeve, the construction and arrangement being such that the assembled collet can be connected to said means for effecting relative movement. In preferred apparatus the sleeve is adapted to be rotated to rotate the collet, thus to rotate the bar.

There now follows a detailed description, t6 be read with reference to the accompanying drawings, of apparatus, reinforcement means and a method embodying the invention. It will be realised that the apparatus, reinforcement means, and method have been selected for descrpton to illustrate the invention by way of example.

In the accompanying drawings: Figure 1 is a diagrammatic view in section of apparatus embodying the invention: Figure 2a is a pers!pective view of reinforcement means embodying the invention; Figure 2b is a perspective view showing s reinforcement plate of reinforcement means embodying the invention; Figure 3 is a perspective view with parts broken away showing three reinforcement bars embodying the invenion; Figure 4 is a perspective view of a sleeve or apparatus emoouying the invention; Figures 5a - Sc are views showiny collet parts of apparatus embodying the invention; Figure 6 is a view in section of an alternatlve illustrative apparatus; and Figure 7 is a view in section of a holder for the apparatus of Figure 6.

In Figure 1 apparatus embodying the invention is shown, suitable for use, in carrying out a method embodying the invention, of installing a reinforcement means for reinforcing substrata for example in mines or buildings.

The illustrative apparatus is suitable for use in installing reinforcement means (see Figure 2a) comprising a reinforcement bar 10 and reinforcement plate 12, the bar 10 being adapted to be inserted into a hole 14 in substrata 16 with an end portion 18 of the bar projecting and with support means, provided by the reinforcement plate 12, carried on the projecting end portion 18 with the ena portion received in a hole 20 in the reinforcement plate. The illustrative apparatus comprises gripping means 22 (to be described in more detail hereinafter) adapted to grip the projecting end portion 18 and a presser member 24 having a face 26 adapted to engage a portion of the reinforcement plate 12.The illustrative apparatus further comprises means comprising a piston and cylinder arrangement 28 for effecting relative movement of the gripping means 22 and the presser member 24 in a direction lengthwise of the bar 10 gripped by the gripping means 22 in the operation of the apparatus whereby to deform the reinforcement plate 12 bounding the hole 20 into gripping engagement with the projecting end portion 18 of the bar 10.

The means for effecting relative movement of the gripping means 22 and presser member 24 comprises a hydraulic piston and cylinder arrangement 28 including an outer cylinder 30 in which is mounted, for sliding movement a piston 32. The cylinder 30 has a threaded portion 38 for connection to a suitable operating device ny wnich hydraulic fluid under pressure, e.g. water may be fed through a pipe system 34 to a chamber 36 in the cylinder 30 in front of the piston 32. If necessary a pressure intensifier of known construction may be included, to increase hydraulic pressure.Supply of fluid to the chamber 36 is effective to move the piston 32 relative to the cylinder 30 in the direction indicated by the arrow A; the piston 32 may be returned in the opposite direction by a suitably positioned spring (not shown) or by supply of hydraulic fluid at the opposite side of the piston 32 whilst exhausting the chamber 36.

Connection of the cylinder 30, for example by the threaded portion 38, to a suitable operating device e.g.

a drill is such as to rotate the cylinder 30 about an axis X of the cylinder 30 which extends in the lengthwise direction of the reinforcement bar 10 in the operation of the illustrative apparatus. A high pressure water swivel of known construction may conveniently be used for this purpose. Such a device accepts water or other hydraulic fluid into a sealed non- rotating body having a rotating hollow shaft: this allows water or other hydraulic fluid to be injected e.g. into a drill string or the illustrative apparatus sq that the feed hose remains static while the illustrative apparatus can be rotated to mix the resin; thereafter the pressurised fluid can be supplied with the swivel to set the reinforcement assembly.

The piston rod 40 terminates in a connecting portion conveniently provided by a head 42 at the end of the piston rod 40.

The presser member 24 comprises a sleeve 44 (see Figure 4) which when the illustrative apparats is in use is coaxial .rJ sith the cylinder 30. Sleeve 44 is provided wltn an opening 46 (hexagonal in the illustrative apparatus) in which the gripping means 22, namely half collets 4d, 50 (see also Figure 5) are adapted to be slidingly received. The sleeve 44 also comprises an opening 52 in the presser face 26 of the presser member 24. The presser member 24 further comprises doys 54 positioned at the opposite end to the presser face 26 and adapted to engage in complementary recesses in the end portion of the cylinder 30 adjacent the presser member 24 when the illustrative apparatus is assembled in operative condition.Rotational movement of the cylinder 30 about its axis is thus transmitted to the presser member 24 through the dogs 54.

Half collets 48, 50 are complementary and are adapted to encompass and grip a head 56 on the projecting end portion 18 of a reinforcement bar 10 when the hal-f collets 48 50 are assembled in the opening 46 in the sleeve 44. When in this assembled condition the collet also encompasses and grips the head 42 on the end of the piston rod 40 thus to connect the assembled collets to the piston and cylinder arrangement 28. As can be seen viewing Figure 1, the end portion 18 of the reinforcement bar 10 extends through the opening 52 in the sleeve 44 into the opening 46 for engagement by the collet halves 48, 50. 1 As can be seen viewing Figure 5, the two collet halves, when assembled, are also of hexagonal configuration complementary with the configuration of the opening 46.Thus, rotation of the sleeve 44, driven by the cylinder 30 is effective to also rotate the collet halves 48, 50. Likewise, movement of the piston 32 in the direction indicated by the arrow A is effective, through the head 42, to move the collet halves 48, 50 in the direction of the arrow A.

Turning now to Figure 3, three different reínrorcenent bars 10a, lob, 10c each having a head 56 are shown. The reinforcement bars each comprise a first portion ó0 adapted to be inserted into a hole (for example the hole 14) and a second portion, namely the end portion 18 adapted to project from the hole 14. Each of the bars 10 comprises a weakened portion 62 by which the head 56 is separated from the remainder of the end portion lt3; as can be seen from Figure 3 the weakened portion 62 is in each case provided by a necked portion of the bar. The necked portions of the bars 10a and 10b both comprise flatted portions 64. The necked portion of the bar 10c is of cylindrical configuration; however, the bar 1Oc comprises flat portions 66, 68 on the head 42 and portion 18. The half collet 48 shown in Figure Sc is intended to be used wither with the bar 10a or the bar 10b; when used with the bar 10b, the half collet 50 used in conjunction with the collet 48 will be of identical configuration and the portion 64 will receive the projection 70. The head 42 on the piston rod 40 will be received in the collet with a flatted portion (not shown) in engagement with the shoulder 72 in the collet half 48.

The collet half 48 shown in Figure Sc will also be used in conjection with the collet half 50 shown in Figure 5a with the reinforcement bar 10b, the cylindrical portion of the projecting end 18 opposite the flatted portion 64 being received in the cylindrical opening 74 in the collet half 50. The piston rod 40 in both cases is received in an opening 76 in the collet halves 48, 50 shown in Figures 5a and 5c.The collet half 48 shown in Figure 5b is intended for use with the reinforcement bar 10c, the piston rod 40 being similarly received in the opening 76 with the head 42 within the collet, whilst the cylindrical necked portion 62 of the bar 10c is received in a hal cylindrical recess 79. A shoulder (not visible in Figure Sb) within the collet engages the flat surface 6s on the head 56. In each case, tlerefcre, engagement of portions of the half collets, 48, 5C with the flatted portions 64, 66 of the reinforcement bars 10 is effective to transfer rotary movement about the axis X of the cylinder from the gripping means 22 to the reinforcement bar 10.

A reinforcement bar 10 and reinforcement plate 12, when assembled, provide a reinforcing assembly (see Figure 2a). The reinforcement plate 12 is generally flat but has deformable portions provided by ears 80 bent out of the plane of the reinforcement plate 12, the ears 80 being bent towards the head of the bar 10 (see Figure 1).

Suitably the reinforcement plate 12 is made of an appropriate grade of steel. The reinforcement ba-r 10 may have ribs 82 extending lengthwise of the bar; these may facilitate location in the plate 12 for gripping by the ears 80 in carrying a method of using a reinforcement assembly.

In carrying out a method embodying the invention of installing reinforcement means comprising a reinforcement bar 10 and reinforcement plate 12 for reinforcing substrata in mine roofs or concrete structures the bar 10 is secured in the hole 14 with the end portion 18 projecting through the hole 20 in the reinforcement plate 12 as shown in Figure 1 of the drawings. The reinforcement bar 10 is preferably secured in the hole by a known system in which curing resin is introduced into the hole 14 for example in a two-part pacK and the bar 10 is then introduced into the hole and rotated to break the pack seal and to mix the resin. The resin is allowed to cure to secure the bar in the hole. In order to rotate the steel bar, the illustrative apparatus is used.

Before the bar 10 is inserted into the hole 14 the collet halves 48, 50 are assembled about the heads 42, 56 of the piston rod 40 and the bar 10 respectively and the sleeve 44 (which has previously been positioned on the bar 10 in the correct orlentation) is slid over the collet halves 4d, 50 to the position to which it is shown in Figure 1 to hold the collet halves 4, 5 in gripping engagement around the bar 10 and piston rod 40. The dogs 54 are engaged in recesses in the cylinder 30.The cylinder 30 is then connected by means of the threaded portion 38 to a suitable device e.g. a high pressure water swivel as outlined above and the cylinder 30 rotated, thus to rotate the sleeve 44, collet halves 48, 50 and thereby the bar 10 to mix the resin.

When the resin in the hole 14 has cured, the bar 10 will be firmly secured in the hole in the position in which it is shown in Figure 1 of the drawings. Hydraulic fluid, namely water, under pressure is introduced into the chamber 36 to drive the piston 32 in the direction of the arrow A relative to the cylinder 30. As the bar 10 is firmly secured by the resin in the substrata 16, this actually causes the cylinder 30 to move in the direction opposite the arrow A, that is towards the substrata 30, thereby urging the presser member 24 towards the reinforcement plate 12.The pressing face 26 of the presser member 24 engages. the ears 80 and deforms the reinforcement plate by crushing the ears 80 bounding the hole 20 into gripping engagement with the bar at the same time forcing the flat portion of the reinforcement plate 12 into firm supporting engagement with an outer surface 86 of the substrata 16. The reinforcement bar 10 is designed sp that the bar fractures at the necked portion 62, detaching the head 56 when the load applied by the illustrative apparatus reaches a pre-selected level sufficient that the force applied to deform the plate 12 into gripping engagement with the bar 10 will be sufficient to achieve a predefined setting load.

In an alternative apparatus, shown in Figure 6, a high pressure swivel is not used, as such is only necessary where the mine roor is high and difficult to reach. The alternative apparatus is generall similar (except as herein described) to the apparatus. shown in Figure 1 and like numbers represent like parts; as can be seen, the pressing face 26 of this alternative apparatus.

is domed. The alternative apparatus has a hexagon drive shaft 90 instead of the threaded portion 38 and the shaft 90 is adapted to be received in the chuck of a drill (not shown) so that the apparatus can be rotated, thus to rotate the bar 10 whereby to mix the resin. After the resin has been mixed it cures in about thirty seconds.

The drill chuck is removed and the apparatus connected to a supply of water (or other hydraulic fluid) which is supplied through a passage 92 in the shaft 90 and an extension 91 thereof into a chamber 94 in the piston 32.

Passages 96 in the piston 32 connect the chamber 94 with the chamber 36 in the cylinder. Sealing means 98 creates a seal between the extension 91 and piston 32 so that movement to and rro in the direction of the arrow A can take place.

Figure 7 shows an adapter 100 by which a hose may be connected to the shaft 90. The adapter has a feed tube terminating in a socket 104 adapted to receive the shaft 90. At the opposite end of the tube 102 to the socket is a hose connection 106 e.g. a 1/4" (0.635 mm) BSP hose connection to which a hose can be connected. A release sleeve 108 is slidably mounted round the feed tube 102 for movement in the direction indicated by the arrow B.

When retracted so that an end portion 110 of the sleeve 108 is clear of the socket 104, the shaft 90 may be inserted in the socket 104 until a connecting nipple 112 on the shaft 90 engages in a recess 114 in the socket 104: the passage 92 is thus connected with a feed passage llo in the tuse 102 through which liquid under pressure can be supplied by a hose attached to the connection 106.

In order to retain the adapter 100 in place the sleeve 108 is slid to the position in which it is shown in Figure 7 with the spcket 104 received in the end portion 110. When in this position balls 118 housed in the socket 104 are urged into an annular groove 120 in an end portion of the shaft 90, thus locking the adapter 100 to the shaft 90. After the bar 10 has been inserted the head 56 breaks off and the apparatus can be removed using the sleeve 108 as a handle. The adapter 100 may be removed from the shaft 90 by again retracting the sleeve 108 along the tube 102, allowing the balls 118 to leave the groove 120.

The reinforcement bars 10 are suitably of a steel material having a hardened skin and a softer core so that the necked position (which extends considerably into the softer core) readily can be made significantly weaker than the remainder of the bar.

The illustrative method allows the use of bars with softer cores and hardened skins thus effecting a consideraole saving In material costs by comparison with known through-hardened reinforcement bars and furthermore eliminates the need for skimming and threading of the projecting end portion of the bar without significantly changing the overall strength of the reinforcement bar 10. Furthermore, the threaded bolts currently in use have to be random checked after installing to ensure that they have been adequately tightened. The illustrative method in which the head 56 of the bar 10 is pulled off when a predetermined load is reached ensures that each reinforcement assembly is proof load tested on installation. Furthermore, the method can be simply introduced with little need for further specialised equipment.

Claims (26)

1. Apparatus suitable for use in installing a reinforcement means for reinforcing substrata in which the reinforcement means comprises a bar adapted to be inserted into a hole in the substrata with an end portion projecting therefrom and support means on the projecting end portion with the end portion received in a hole in the support means, the apparatus comprising gripping means adapted to grip the projecting end portion of the bar, a presser member adapted to engage a portion of the support means and means for effecting relative movement of the gripping means and the presser member in a direction lengthwise of a bar dripped by the gripping means in the operation of the apparatus whereby to deform the support means bounding the hole into gripping engagement with the projecting end portion of the bar.

2. Apparatus according to Claim 1 wherein said means effecting relative movement comprises a hydraulic piston and cylinder arrangement.

3. Apparatus according to either one of the preceding claims adapted to be rotated whilst a bar is gripped by the gripping means, thus to rotate the bar about an axis extending lengthwise of the bar.

4. Apparatus according to any one of the preceding claims wherein the gripping means is adapted to grip a headed portion provided at an extremity of the projecting end portion of the bar.

5. Apparatus according to Claim 4 wherein the -gripping means comprises complementary half collets adapted to be slidingly received in a sleeve which provides the presser member, the half collets encompassing and gripping the headed end portion of the bar when assembled in the sleeve.

6. Apparatus according to Claim 5 so constructed and arranged that the assembled collet can be connected to said means for effecting relative movement.

7. Apparatus according to either one of Claims 5 and 6 wherein the sleeve is adapted to rotate a collet gripping a bar thus to rotate the bar.

8. Apparatus suitable for use in installing a reinforcing means for reinforcing substrata constructed arranged and adapted to operate substantially as hereinbefore described with reference to either one of Figures i and 6 of the accompanying drawings.

9. A method of installing reinforcement means comprising a reinforcement bar and support means for reinforcing substrata comprising securing a reinforcement bar in a hole in the substrata with an end portion projecting therefrom and projecting through a hole in the support means, and deforming the support means bounding the hole into gripping engagement with tne bar with the support means in supporting engagement with a surface of the substrata.

10. A method according to Claim 9 wherein the support means is a generally flat reinforcement plate.

11. A method according to Claim 10 wherein the reinforcement plate comprises opposed ears bounding the hole the ears being deformed into gripping engagement with the bar.

12. A method according to any one of Claims 9 to 11 wherein the projecting end portion of the bar is gripped by a suitable tool and a presser member of the tool is pressed into engagement with the support means -to urge the support means firmly into engagement with said surface and to deform the support means.

13. A method according to Claim 12 wherein the projecting portion of the bar has a head to provide means by which the bar can be gripped by the tool.

14. A method according to Claim 13 wherein the bar is provided with a weakened portion between the head and the remainder of the bar which is arranged to break when the load applied reaches a pre-selected level sufficient that the force applied to deform the plate into gripping engagement with the bar will have been sufficient to achieve a predefined adequate gripping force.

15. A method according to Claim 14 wherein the weakened portion is provided by a necked portion of the bar.

16. A method according to any one of Claims 9 to 15 wherein the bar is secured in the hole in the substrata by a curing resin.

17. A method of installing reinforcement means comprising a reinforcement bar and support means for reinforcing substrata substantially as hereinbefore described with reference to the accompanying drawings.

18. A reinforcement bar suitable for use in reinforcing substrata compr sir.g a first portion adapted to be inserted in a hole in substrata to be reinforced and a second portion adapted to project from the hole, the second portion comprIsing a head and a weakened portion by which the head is separated from the remainder of the second portion.

19. A reinforcement bar according to Claim 18 wherein the weakened portion is provided by a necked portion of the bar.

20. A reinforcement bar suitable for use in reinforcing substrata substantially as hereinbefore described and as shown in Figure 3a of the drawings.

21. A reinforcement bar suitable for use in reinforcing substrata substantially as hereinbefore described and as shown in Figure 3b of the drawings.

22. A reinforcement bar suitable for use in reinforcing substrata suostantially as hereinbefore described and as shown in Figure 3c of the drawings.

23. A reinforcing assembly suitable for use in reinforcing substrata comprising a reinforcement bar according to any one of Claims 18 to 22 and support means on the second portion of the bar the second portion being received in a hole in the support means.

24. A reinforcing assembly according to Claim 23 wherein the support means is. a generally flat reinforcement plate having deformable portions bounding the hole.

25. A reinforcing assembly according to Claim 24 wherein the deformable portions. comprise opposed ears bent out of the plane of the plate towards the head of the bar.

26. A reinforcing assembly suitable for use in reinforcing substrata substantially as hereinbefore described with reference to Figure 2a of the accompanying drawings.