CN102239310A - rock bolt parts - Google Patents

Abstract

A rock bolt (10) comprising at least two elongate axially aligned rods (14) having adjacent ends (18), the adjacent ends (18) being interconnected by relative movement (50) perpendicular to a longitudinal axis (28A), whereby a tension load and torque transferring undercut formation (24) on one elongate rod engages a complementary formation on the other elongate rod.

Description

rock bolt parts

Background of the invention

The present invention relates to a rock bolt suitable for strengthening rock.

As used herein, "rock" includes rock formations, cementitious bodies, or similar hard materials.

Providing support is critical in underground mining excavations. This support must be provided in a cost-effective manner.

Examples include hydraulically or mechanically extendable mining helical studs, slender wooden supports, wire bound square timber rafts, mechanically actuated or grouted rock bolts or wire anchors, and bags or pipes filled with settable material The supporting structure of the body is used to provide support.

In narrower excavations, mechanically secured anchors or rock bolts are not widely accepted due to space constraints. In narrow and confined spaces, it is difficult to drill vertical holes up to 2 meters long for steel anchors. Extended drilling techniques using coupling rods must be relied upon. There are also problems with the installation of steel anchors. Steel anchors should have a length approximately twice the height of the working face to be supported and therefore must consist of a number of shorter sections bolted together when installed using extension sleeves. An example of this approach is disclosed in Au 2005 204239.

Polyester resin is usually used to anchor the shank in the hole. The amount of resin required to fill the annular space around the bolt shank in the bore can be substantial and the resin is expensive. Also, if the amount of resin is very large, the bonding strength of the resin may decrease and the steel anchor may not be able to bear its design load. Also, it is difficult to assess the quality of the installation because the bolt shank must be rotated during installation to break the resin capsule and mix the resin. Insufficient or excessive rotation adversely affects the shear strength of the resin.

A nut engaged with the protruding threaded end of the bolt shank is fastened to a face plate engaged with the bolt shank and resting on the rock surface. The protruding end of the bolt shank remains exposed, which is undesirable because the protruding bolt shank may significantly restrict the movement of personnel and machinery in shallower excavations.

The object of the present invention is to provide a rock bolt which can be configured in various lengths according to needs and which solves the above-mentioned problems.

Contents of the invention

The present invention provides a rock bolt component comprising an elongated shaft including a body having opposed first and second ends, and the elongated shaft has a set of first locking formations at the first end, wherein the locking At least one of the formations has an undercut surface perpendicular to the longitudinal axis of the elongated rod.

Each locking formation may take the form of a rib and a corresponding recess may be provided between each pair of adjacent ribs.

As used herein, "undercut" means that a corresponding formation can engage a complementary formation in a similar rod only in a sliding action in which one elongated rod is drawn perpendicular to the longitudinal axis of the other elongated rod. to move.

Preferably, the undercut locking formations are such that there is a natural tendency to align the bars longitudinally with each other when a complementary formation on the second bar engages therewith. This can be achieved by forming the undercut surface with an arcuate or V-shape when viewed from one side (not in cross-section).

The rod may include a set of second locking formations at the second end. The second formation may be complementary in shape to the first locking formation.

It is an object of the invention that if a first formation on a first part is joined to a second formation on a second part, the joint thus formed between the two parts is capable of transmitting a tensile stress exceeding a predetermined minimum value, And the maximum width of the joint (in a direction perpendicular to the longitudinal axis of the joint) should not be significantly greater than the width or diameter of the body of each component.

In one version of the invention, the first formation is an undercut formation that is arcuate relative to the longitudinal axis of the rod. Each formation may be a rib flanked by opposing recesses and having opposing side walls sloped towards the longitudinal axis of the body such that the outermost surface of the rib is wider than the base of the rib.

The first formations may be axially spaced from each other at the first end.

Since the shape of the second formation is complementary to the first formation, the same features as described above with respect to the first formation apply to the second formation.

The surface of the body may comprise any suitable type of mixing or anchoring formations.

In a variant of the invention, the part comprises an anchoring formation or anchoring mechanism at one end of the rod. Such formations or mechanisms may be of any suitable type. In one embodiment, a wedge-shaped structure is used which, when actuated, enlarges or increases the effective cross-sectional dimension of said end of the rod.

The present invention also provides a rock bolt comprising at least first and second rock bolt parts, each rock bolt part being a rock bolt part of the type described above, wherein the longitudinal axis of one part relative to the other part is sideways. Moving groundwardly engages the first formation of the first component with the second formation of the second component. The lateral movement may be performed in a straight line or alternatively in an arcuate movement.

The rock bolt may include a third rock bolt component of the type described above, which engages the second component in a manner similar to that described. This process can be repeated to extend the overall length of the rock bolt.

Due to the undercut nature of the locking formations, torque can be transmitted from one component to another, eg to mix grout or resin.

A tubular sleeve is threadably engageable with the second end of the first rock bolt component.

The sleeve may include formations engageable with an external tool such that the sleeve may be rotated in a first direction or in a second direction opposite the first direction.

An end of the sleeve remote from the first rock bolt component is engageable with a load distribution washer.

The present invention also provides a rock bolt comprising: a first part and a second part, the first part including a body having a first end and a second end; a tubular sleeve threadedly engaged with the second end; a locking portion , the locking portion allows torque to be transmitted between the first part and the sleeve so that the sleeve and first part can rotate together in a first direction, and the locking portion allows the sleeve to rotate relative to the first direction in a second direction opposite to the first direction. The parts rotate; the second part is axially aligned with the first part, the two parts comprising complementary interengaging tensile load and torque transmitting undercut formations at adjoining ends.

The sleeve engaging the first part is preferably connected to the load transfer washer.

The undercut formations of the first and second parts may be brought into mutual engagement by moving one part perpendicular to the longitudinal axis of the other part. Such movement may be linear, but preferably such movement follows an arcuate path.

The present invention also provides a method of extending the length of the shaft of a rock bolt, the rock bolt comprising a first member having an elongated body and a plurality of undercut formations at one end of the elongated body that transmit tensile loads and torque, the The method includes the step of engaging a tensile load and torque transmitting undercut formation at the end of the second member with a formation on the first member.

Once the rock bolt rod is inserted into the hole in the rock mass, the hole walls ensure that the formations remain engaged with each other.

Description of drawings

The present invention is further described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a side view of a type of rock bolt according to the present invention;

Figure 2 shows a cross-sectional view of the rock bolt of Figure 1;

Figure 3 is an enlarged side view of a joint formed between two adjacent components in the rock bolt of Figure 1;

Figure 4 is an enlarged cross-sectional view of one end of the rock bolt in Figure 1;

Figure 5 is an enlarged cross-sectional view of a joint between two adjacent components in a rock bolt;

Figure 6 shows the rock bolt during installation;

Figure 7 shows the upper end of the rock bolt;

Fig. 8 and Fig. 9 are similar to Fig. 5 and Fig. 6 respectively, and Fig. 8 and Fig. 9 show the variation of the present invention; And

Figure 10 is similar to Figure 4 and shows a variant of the invention.

Detailed ways

FIG. 1 of the drawings shows a side view of a rock bolt 10 comprising a first component 12 and a plurality of additional components 14 in accordance with the present invention. As will become apparent from the description below, the components 14 are generally identical except for one uppermost component ( FIG. 1 ), labeled 14A.

The number of components that can be included in a rock bolt can vary as desired.

Figure 2 shows a side sectional view of the rock bolt.

Also partially shown in FIG. 4 is an enlarged cross-sectional view of component 12 , which includes an elongated body 16 having a first end 18 and a second end 20 . The elongated body has on the outside a plurality of grooved formations 22 (see FIG. 1 ) which aid in the mixing of resin or grout and also serve as retention or locking formations when rock bolts are installed.

The first end 18 is formed with a plurality of first formations 24 , enlarged cross-sectional views of the formations 24 are shown in FIGS. 5 and 6 . The formations are irregular in shape, but generally the formations are undercut. In this example of the invention, the formations can be classified into two ribs 24A and 24B and two grooves 24C and 24D, respectively. Rib 24A has a planar outer surface 26 generally parallel to the longitudinal axes 28 and 28A of the component, and sloping walls 28 and 30 , each having a tapered shape away from planar outer surface 26 and toward each other. surface. These features give the ribs their undercut nature.

Slot 24C has a flat base 32 and is bounded by a wall 30 on one side and a wall 34 generally perpendicular to longitudinal axes 28 and 28A. The rib 24B has a flat outer surface 36 flanked by a wall 34 and a wall 38 having a surface inclined away from the surface 36, so that the rib 24B also has an undercut nature. The groove 24D has a flat base 40 bounded by a sloped wall 38 and an opposing wall 42 .

Component 14 adjacent component 12 has a first end 40 and a second end 46 . An enlarged detailed cross-sectional view of the second end is shown in FIG. 5 , and the second end is provided with a plurality of formations 48 whose cross-sectional shape conforms to the formations 24 . Due to the undercut nature of the ribs and grooves, it is apparent that the formation 48 can only engage the formation 24 when the set of formations is moved perpendicular to the longitudinal axes 28 and 28A so that the formations can be moved by a mutual sliding movement. join each other.

FIG. 3 is a view rotated 90° about the axes 28 and 28A of the view in FIG. 5 . Component 12 is shown in dashed lines where it is aligned with component 14 and is shown in solid lines where longitudinal axis 28 of component 12 is inclined toward longitudinal axis 28A of component 14 . Formations 24A to 24D extend perpendicular to longitudinal axis 28 . There are two possibilities for this connection. If the sides of the ribs and grooves (30, 34, 38, 42) are both perpendicular to the longitudinal axes 28 and 28A, one component moves linearly laterally relative to the other, causing the complementary ribs and grooves to engage each other. Alternatively, as shown in FIG. 3 , the surfaces 30 , 34 , 38 , 42 may each lie on an arc whose center lies on the longitudinal axis 28 . With this arrangement, it is only possible to engage a formation on one part with a complementary formation on the other part if, as shown, one part is initially tilted relative to the other part. Thus, the joining process is a process (as shown) in which part 12 is moved relative to the other part along an arcuate path (as shown by arcuate arrow 50 in Fig. 3) until the two parts are axially aligned.

The arc formation and motion have many advantages. First, if tension is applied to the mutually engaging parts, whether by mechanical means or by gravity, there is a tendency for the parts to self-align longitudinally with respect to each other. Second, the parts cannot be disengaged from each other simply by moving one part sideways relative to the other. This means that when the components are installed into the holes in the rock mass, as shown in Figure 6, the components remain engaged with each other. No retaining means (eg tubes) are required to keep the components engaged with each other. Also, the joint is capable of transmitting torque. A third factor is that the pivotal type of movement required to couple one component to another is advantageous in limited space conditions, e.g. narrow slopes, because the components only work when they are pushed into a hole in the rock mass are completely axially aligned with each other.

The end 40 of the part 14 has a formation 52 which is identical in all important respects to the formation 24 except that the formation 52 faces in the opposite direction to the formation 24 when the formation 46 is engaged with the formation 24 .

FIG. 4 shows an enlarged cross-sectional view of the second end 20 of the component 12 . The second end has a threaded rod 64 protruding from the remainder of the body 16 . One end 72 of the tubular sleeve 68 has internal threads 70 . The locking wire 74 acts between the threaded rod 64 and the threaded part 70 .

The opposite end of the sleeve 68 has an enlarged flare 76 adjoining the edge 78 of a load distribution washer 80 having a central bore 82 through which the sleeve extends. A drive formation 84 is formed on the inner side of the protruding flare 76 .

The part 14A at the end of the rock bolt 10 remote from the load distribution washer 80 has an inboard end 88 carrying a formation 90 similar to the formation 24 . The outboard end 92 of the body 94 of the component 14A is axially bisected by a longitudinally extending slot 96 , see FIG. 7 . The elongated wedge member 98 has a front end 100 that is inserted into the slot 96 such that the sides of the wedge member frictionally engage the sides of the slot. FIG. 2 shows a cross-sectional view of an assembled rock bolt, and FIG. 6 shows an enlarged view of a rock bolt installed in a hole 102 formed in a rock body 104 from a rock surface 106 .

The rock bolt 10 is easily assembled on site. Part 14A with wedge member 98 is inserted into hole 102, but end 88 protrudes slightly from the hole. Subsequently, adjacent parts 14 are connected to part 14A generally in the manner shown in FIG. The undercut formations of adjoining ends engage each other. Once mutual engagement is achieved, part 14 is moved into the hole, part 14A advancing towards the end of the hole.

The joint between the two parts then moves into the hole 102 . Once the joint is in the hole, the parts cannot disengage from each other because the parts can only disengage from each other when one part moves in an arcuate path relative to the other, this movement is when the mutually engaged ends of the parts are in the hole is impossible. Due to the centering action of the arcuate formations, when the parts are tensioned, one part is not laterally biased to a great extent relative to an adjacent part, effectively eliminating any bias.

The above process continues in this manner, wherein the effective length of the rock bolt 10 is extended by adding the next component 14 as required.

The final component to be added to the assembly is component 12 carrying the load distribution washer 80 . The component 12 and gasket 80 are delivered to the installation site in an assembled state. Fully screwing the threaded rod 64 into the sleeve 68 prevents damage to the threads on the screw rod by the sleeve. The initial formation surface 106 is spaced apart from the gasket. The hole 102 is drilled to a length that ensures that the front end 108 of the wedge member 98 abuts the end 110 of the hole 102 . Thus, the rock bolt may be set by mechanically applying an impact force to the protruding end 76 to drive the component axially into the bore 102 . The wedge member 98 is then urged into the slot 96 whereby the end 92 of the component 14A expands radially.

One or more resin or grout bladders (not shown) are inserted into the holes 102 prior to performing the foregoing process. The contents of these pockets are released into holes 102 as the rock bolt is pushed in sufficiently so that the wedge member and front end 92 of component 14A pierces the pockets. A tool (not shown) engages the formation 84 on the protruding end 76 of the tubular member 68 . The tool is actuated to cause the rock bolt to rotate in the hole so that the contents of the bladder are thoroughly mixed and ensure that the mixture is distributed along the length of the rock bolt to the outside of the rock bolt. Thereafter, the described actuation process is started, thereby mechanically setting the rock bolt. As the case may be, the resin or grout mixture is then allowed to set to create a bond between the outer surface of the rock bolt and the hole wall. This bond is enhanced by grooved formations 22 on the outer body surface of each component.

Torque can be transmitted from the sleeve 68 in a counterclockwise direction to the rest of the rock bolt by means of the locking wire 74 which prevents the sleeve from being unscrewed off the threaded rod 64 . Once the settable material (resin or grout) has set, the tool re-engages the formation 84 and rotates the sleeve 68 in a clockwise direction. The sleeve can be advanced in a helical fashion along the rod 64, during which time the distribution washer 80 is pressed against the rock surface 106 and the bolt is stressed in the axial direction. The direction of the threads on the threaded rod and correspondingly on the sleeve is only exemplary, since in some countries right-handed threads may be prevalent, while in other countries left-handed threads may be prevalent.

Mechanical placement provides immediate support, while the settable material forms permanent support after setting.

It will be apparent from inspection of the drawings that the length of the rock bolt can be extended as desired by use of additional components 14, if desired.

Once the rock bolt is installed, the load distribution washer 80 and the end 76 of the sleeve 68 are practically flush with the formation surface 106, and the load distribution washer 80 and the end 76 of the sleeve 68 themselves do not interfere in the excavation. Movement of people or machines.

The formations used to interconnect adjacent components are formed using conventional milling techniques. The size and number of these formations can vary as desired. FIG. 8 is similar to FIG. 5 and shows the interengaging formations 124 and 146 located at adjoining ends 118 and 146 of the modified components 112 and 114 respectively. Comparing Figures 5 and 8, it can be seen that Figure 8 shows that the formations 124 and 148 both have dovetail properties, whereas in Figure 5 one set of formations has flat sides perpendicular to the longitudinal axes 28 and 28A. The dovetail structure shown in FIG. 8 is slightly more difficult to manufacture than the structure shown in FIG. 5 . In both cases, however, a good lock is ensured and, as mentioned, no retaining member is required to surround the joint to ensure that the parts remain engaged with each other. In effect, the wall of the hole in the rock acts as a sleeve surrounding the joint, which is supported by the wall of the hole and the surrounding grout.

FIG. 9 is similar to FIG. 6 and shows components 112 and 114 of rock bolt 10A. The front end of the rock bolt does not have the wedge-shaped structure shown in FIG. 7 . In this case, the rock bolts are glued or fixed in place by resin and thereafter tensioned by advancing a threaded sleeve 68 at the mouth of the hole 102 on the rock surface 106 .

The front end of the rock bolt may also carry a mechanically actuated expansion housing assembly of the type known in the art. The invention is not limited in this respect.

Figure 10 shows another variant of the invention. In this variant, a resiliently compressible element 184 , made of, for example, a rubber block, is provided on an inner surface 188 of the gasket 80 . The rubber element has a central channel 188 through which the tubular sleeve 68 passes.

The rock bolt shown in Figure 10 was used in a similar manner to that described herein. As the sleeve 68 is rotated in a clockwise direction, the sleeve advances in a helical fashion along the rod 64 in order to tension the rock bolt, during which time the element 184 is compressed. As a result, the rock bolt is stressed in the axial direction.

Claims (11)

CLAIMS 1. A rock bolt component comprising an elongated shaft comprising a body having opposed first and second ends, and the elongated shaft has a set of first locking formations at the first end, Wherein at least one of the locking formations has an undercut surface perpendicular to the longitudinal axis of the elongated rod. 2. A rock bolt component as claimed in claim 1, wherein each locking formation is in the form of a rib and a corresponding recess is provided between each adjacent pair of ribs, said bottom when viewed from one side The cut surface has an arc or V shape. 3. The rock bolt assembly of claim 1 , wherein said elongated shaft includes a set of second locking formations at said second end, said second formations intersecting with said first locking formations. Complementary shapes. 4. The rock bolt component of claim 1, wherein said first formations are undercut formations that are arcuate with respect to the longitudinal axis of said elongate shaft, each formation being flanked by opposing The ribs of the recesses have opposite side walls inclined toward the longitudinal axis of the body such that the outermost surfaces of the ribs are wider than the bases of the ribs. 5. The rock bolt assembly of claim 1 , wherein said rock bolt assembly includes a wedge device at one end of said elongated shaft, said wedge device being actuatable to increase the length of said elongated shaft. The effective section size of the end. 6. A rock bolt comprising at least first and second rock bolt components, each rock bolt component being a rock bolt component according to claim 1 , wherein the longitudinal axis of one component relative to the other is sideways. Moving groundwardly engages the first formation of the first component with the second formation of the second component. 7. The rock bolt of claim 6, wherein the rock bolt includes a tubular sleeve engageable with a load distribution washer, threaded with the second end of the first rock bolt component and the tubular sleeve includes formations engageable with an external tool such that the sleeve can be rotated in a first direction or in a second direction opposite to the first direction. 8. A rock bolt comprising: a first component comprising a body having a first end and a second end; a tubular sleeve threadedly engaged with the second end; a locking portion , the locking portion allows torque to be transmitted between the first member and the sleeve so that the sleeve and the first member can rotate together in a first direction, and the locking portion allows the sleeve relative to said first member in a second direction opposite to said first direction; and a second member axially aligned with said first member; the two members comprising complementary interengagement at abutting ends Undercut formations that transmit tension loads and torques. 9. The rock bolt of claim 8, wherein the undercut formations of the first and second members are interengaged by moving one member transversely relative to the longitudinal axis of the other member. 10. A method of extending the length of the shaft of a rock bolt comprising a first member having an elongated body and a plurality of tensile load and torque transmitting bottoms located at one end of the elongated body The method includes the step of engaging a tensile load and torque transmitting undercut formation at the end of the second member with the formation on the first member. 11. A method of installing a rock bolt into a hole in a body of rock, the method comprising the steps of: extending the length of the shaft of the rock bolt outside the hole using the method of claim 10; The formations are inserted into the holes, so that the holes prevent the formations from detaching from each other.

Images