GB2043748A - Assembly for securing rock bolts - Google Patents

Abstract

An assembly for securing rock bolts includes a rock drilling machine 46, a resin injection device 5, Fig.5 (not shown), for injecting resin into a hole drilled by the drilling machine, and a bolt introducing device 48 for introducing an anchoring bolt into said hole. <IMAGE>

Description

SPECIFICATION Assembly for securing rock bolts The present invention generally relates to an assembly for securing rock bolts and, for example, of the kind having a rock drilling machine, a resin injection device for injecting resin into a hole drilled by said drilling machine, and a bolt introducing device for introducing an anchoring bolt into said hole containing resin which on setting fixedly secures the bolt.

For injecting the resin, cartridges have been used containing two separate spaces, one for the resin and the other one for a setting agent. After introduction of a cartridge into the drill hole the envelopes of the two spaces are crushed on the introduction of an anchoring bolt, and resin and setting agent are mixed by rotation of said bolt.

Based upon inter alia, the use of the abovementioned cartridges and a far reaching mechanisation of the drilling, cartridge introduction, and bolt introduction steps it has been possible to design rock bolting assemblies which make possible a rapid fastening of a set of anchoring bolts in a mine drift roof.

Such assemblies are described in e.g., French Patents 1,362,691 and 77,10169.

A disadvantage of the use of cartridges is the comparably high cost by the fact that they need special manufacture. The means in a rock bolting assembly necessary for the manipulation and transport of the cartridges also put a natural limit on how far it is possible to reach as concerns mechanisation and automisation of the steps of operation to be carried through by the assembly.

A further problem with rock bolting devices of the kind described is the difficulty of centering the resin feeding device and the bolt along the line of operation coinciding with the drill hole. This difficulty is due to the comparatively great tolerances which must be admitted at the movements of the different parts of the assembly in order not to raise the costs of the assembly by using unrealistically close manufacturing tolerances.

One object of the present invention is to provide a system by means of which the costs for the resin will be reduced as compared with assemblies using cartridges.

Another other object is to use such a resin injection system for total automisation of the successive steps of operation that must be carried through with a rock bolting assembly for securing a number of anchoring bolts in rock.

Still a further object is to provide means for allowing exact guidance of the resin feeding device along the line of operation determined by the drilling of the drill hole.

According to the invention an assembly for securing rock bolts comprises a rock drilling machine, a resin injection device for injecting resin into a hole drilled by said drill machine, and a bolt introducing device for introducing an anchoring bolt into said hole, the resin injection device including two conduits for separate but simultaneous feeding of resin and setting agent into the drill hole, and connected, respectively, via pumps, to a resin container and a separate setting agent container.

The invention may be carried into practice in various ways but one specific embodiment will now be described more closely below with reference to an embodiment illustrated in the accompanying draw ings, in which:- FIGURE lisa side view schemat- ically shows a vehicle carrying a rock bolting assembly; FIGURES 2,3 and 4 in sideview, planview and end view, respectively, partly schematically show the bolt drilling assembly; FIGURE 5 in sideviewshows a resin injection device including in the assembly according to Fig ures 24; FIGURE 6 shows a connecting diagram for the resin injection device according to Figure 5; and FIGURE 7 in side view and partly in axial section shows a resin pump for the resin injection device.

The vehicle combination according to Figures 1 and 2 includes a traction vehicle 2 and a semitrailer or trailer 4. The trailer carries an unright support 6 for a hydraulic boom arrangement 8. The hydraulic boom arrangement 8 carries at its end a rock bolting assembly 10. The assembly 10 is movable sidewardly as well as vertically by means of the hydraulic boom 8. Furthermore, a rotational movement of the rock bolting assembly around the longitudinal axis of the hydraulic boom is possible.

The rock bolting assembly is carried by a longitudinal frame 12 which in turn is rotatably carried by the hydraulic boom 8 around a transverse shaft 14. The rotational movement is attained by means of a hydraulic cylinder 16 acting between the frame 12 and an end assembly 18 on the hydraulic boom. The end assembly 18 comprises a rotational motor for attaining the rotational movement of the hydraulic boom 8 around its longitudinal axis and is attached to the end of the hydraulic boom by means of a mounting flange 20. The assembly 10 is shown below the frame 12 in Figure 1, and rotated (about the longitudinal axis) to above the frame 12 in Figure 2.

The frame 12 carries two shaft supports 22, one of which is shown in Figure 2, and carrying between them a fixed shaft journal not visible in the Figures.

On this shaft journal is rotatably mounted a cylinder shaft 24. On the shaft 24 is attached a mounting plate 26 by means of flanges 28. On both sides of the shaft 24 the plate 26 carries a pivot bracket 30 for the end of a piston rod 32 of a hydraulic cylinder 34 of a pair of oppositely acting cylinders 34,36 in line with each other. A piston rod 38 of the cylinder 36 is connected at its end to the lower end of a bracket 40, that is rigidly attached to the frame 12.

By means of the cylinders 34,46, on each side of the frame 12, the shaft 24 can be rotated about its axis and thereby the mounting plate 26 be tilted sidewardly in either direction.

Referring to Figure 3, on the plate 26 feed rails 42 and 44 for a rock drill machine 46 and a bolt rotating device 48, respectively, are fixedly mounted in parallel with the shaft 24. Between the drill machine and bolt rotating units 42,46 and 44,48, respectively, extends a resin feeding and injection device 50 having an injection opening at 52.

The function of the rock bolting assembly in operation will now be described briefly. A hole is first drilled by means of the rock drill machine 46 in the wall of a shaft or the like, the surrounding rock of which is secure. This hole is filled by a rapidly setting resin via the device 50, whereupon finally a securing bolt is rotated into the resin filled hole by means of the bolt rotating device 48. A centering device is mounted at the fore end of the frame 12. By means of this centering device each one of the three above described operation steps are centered along an axis or working direction 54. The coarse setting into this axis of the drill rod, the resin feeding device and roof bolt in turn is realised by tilting the carrying plate 26 sidewardly by means of the two pairs of cylinders 34, 36.The drill machine 46, the bolt rotating device 48 and the resin feeding device 50 are drivable forwardly in the working direction 54 along their respective feed rails via the centering device by means of an endless chain drive, in each case, not shown in Figures 24, in a way that is conventional in connection with e.g., rock drill machines.

The centering device shown in Figures 2 and 3 comprises a frame 55 fixed to the fore end of the frame 12. The frame 55 carries a supporting block 56 e.g., of hard rubber. Above the block 56 the frame 55 carries a centering sleeve 57, the axis of which coincides with the axis 54, and which is axially split along a plane containing essentially the axis 54 and the longitudinal axis of the frame 12.

The sleeve 57 on its end facing the assembly, has a funnel-like widened and axially split end portion 57', of which each half is attached to its corresponding sleeve portion. At the opposite end the sleeve 57 is surrounded by a conical, and axially split protection wall 58, of which each a half is associated with its corresponding sleeve portion. The sleeve portions and their associated respective half end portions are pivotally carried by the frame 55 and are swingable outwardly from each other by means of a hydraulic cylinder 59 (see Figure 2), The above mentioned operational steps for securing a bolt into rock follow upon a localisation step in which the block 56 is forced into firm engagement with the wall of the shaft in a position such that the axis 54 points to the desired bolting position.The sleeve 57 with its end portions 57' and 58 is normally closed and serves, by its rearwardly directed funnel-shaped end portion 57' to guide the drill rod, the resin feeding device and the roof bolt when commencing the respective operation steps. The funnel 57' is big eneough to compensate for added coarse tolerances in the assembly determining the respective coarse setting position of the three mentioned members on the tilting movement around the axis of the shaft 24.

Sometimes there can be demands that the anchoring bolt at its outer end is provided with an anchoring plate to engage the rock wall in a conventional manner. In such instances the anchoring bolt, with its rear end provided with said plate, is guided into the drill hole via the centering sleeve 57 is described above. To allow for passage of said plate, the sleeve halves are finnaly opened by means of the cylinders 59.

In operation of the assembly the interior of the conical protection wall 58 is connected to a flexible suction tubing for drill cuttings.

On the same side as the feed rail 44 a bolt magazine is arranged, generally indicated at 60 (see Figures 2 and 3).

In the Swedish patent application 7901617-6, filed on February 22nd 1979, the bolt magazine 60 and its function is described more closely.

The resin injection device 50 includes a feed rail 62, (Figure 3) which, by means of a mounting end flange 64, is connected with the feed rails 42 and 44.

Near the flange 64 a housing 66 for a hydraulic motor of a rotational type is mounted on the rail 62 (see Figures 3 and 5). The hydraulic motor drives a chain wheel indicated at 68, driving a chain 70 which is shown more in detail only over a short portion of its path. The chain 70 also runs over a chain wheel 72 attached near the other end of the rail 62 and forms an endless loop together with a carriage 74 slidable on the rail 62.

As shown in Figure 5, the carriage 74 carries one end of a double tubing of essentially the same length as the feeding rail 62. This double tubing consists of an outer tube 76 and an inner tube 78 arranged coax iaily therein. At their ends located on the carriage 74 the tubes 76 and 78 have separate upwardly curved inlets with connecting means 80 and 82, respectively, for flexible feed conduits 84 and 86, respectively (see Figure 6). At the other end of the double tubing the inner tube 78 protrudes a short distance outside the outer tube 76 and is coaxially held relatively to this by struts 88. At the same end the outer tube 76 is guided in a cylinder shaped housing 90 (Figure 5), that is attached at the corresponding end of the rail 62. The housing 90 contains electric heating coils along its whole length.

Via the conduit 84 the tube 76 is intended to receive a resin from a container 92 (Figures 1 and 6) via a piston pump 94. The tube 78 receives a setting agent for the resin via the conduit 86 from a container 96 by means of a screw pump 97. The resin and the setting agent should be of a type that rapidly sets on mixing. The resin is e.g., a low viscous and thixotropic polyester and the setting agent secures rapid setting thereof.

The pump 94 is driven by a hydraulic motor 98 and the pump 97 is driven by a hydraulic motor 99. Figure 6 includes a hydraulic diagram forth two hydraulic motors.

In Figure 1 the locations of the container 92 and the pump 94, respectively, on the trailer 4 are indicated.

As shown in Figure 7, the pump 94 has an inlet tube 100 leading from the bottom of the container 92 and via a non-return valve leading to a cylindrical chamber 102 in a cylinder 103. The non-return valve includes a valve body 104 spring biased and closing against the inlet direction.

A hydraulic cylinder 106 is coaxially attached to the end of the cylinder 103. The cylinder 106 has at its ends hydraulic fluid inlets 108 and 110, respectively, with inlet connections 112 and 114, respectively, at the end of the cylinder. The cylinders 103 and 106 contain pistons 116 and 118, respectively, which are interconnected by means of a common piston rod 120 passing from one chamber to the other via a sealing body 122. Into the free end of the cylinder 106 an axiallysettable rod 124 extends through a sealing body. More particularly, the rod 124 has a threaded end portion 126 extending through a nut 128, which is fixed relatively to the cylinder 106. A lock nut is indicated at 130.

The cylinder 103 in the vicinity of its input end has a radially extending outlet stud 132 containing a non-return valve with a valve body 134 closing and spring biased against the outlet direction.

In operation, when resin is to be fed into a drill hole the double tubing 76,78 is fed forwardly via the centering sleeve 57 to the inner end of the drill hole, whereupon the pumps 94 and 97 are put into operation while the double tubing 76,78 is simultaneously and successively drawn out of the drill hole. During operation of the pump 94 the piston 116 is drawn to the right in Figure 7 by means of the piston 118 of the hydraulic motor 98, whereby suction is generated that lifts the valve body 104 from its seat and presses the valve body 134 against its seat. A charge of the resin in the container 92 is thereby drawn via the inlet valve into the cylinder chamber 102. The amount is determined by the length of the stroke of the hydraulic piston 118, that in turn is set by means of the stop formed by the end of the settable rod 126.

Discharge of the charge on un-hardened resin drawn into the cylinder 102 is realised in that the piston 116 by means of the hydraulic motor 98 is moved to the left in Figure 7, the valve body 104 then being pressed against its seat and the valve body 134 being lifted from its seat.

The operation of the hydraulic motors 98 and 99 of the two pumps 94 and 98 is synchronised so that resin and setting agent are fed out simultaneously from the double-tubing 76,78. Likewise, a simultaneous synchronisation of the hydraulic motor drive of the carriage 74 is provided. In operation, the tubes 76,78 are furthermore filled with the resin and setting agent, respectively, also between the resin injection steps; thus one can obtain preheating of this filling by means of the heating coils located in the cylinder 90, before next resin injection step is to be carried out, i.e., during bolt introduction into a hole already filled with resin and drilling of a next hole. If necessary it is therefore possible to reduce the setting time of a portion of the resin filling closest to the inner end of the drill hole so that the anchoring bolt adheres immediately upon introduction.During introduction of the bolt it is simultaneously rotated so that resin and setting agent are mixed. Possibly, the bolt can also be further rotated for a short time, for example, under the control of a time relay.

The hydraulic circuits of the three hydraulic motors 66, 98, 99 included in the resin injection device, can as mentioned above, be interconnected to allow, when required, synchronisation and/or co-ordination of their operations. Likewise these hydraulic circuits can in turn be included in a greater hydraulic system including all the hydraulic circuits of the hydraulic drives included in the rock bolting assembly for co-ordination and/or synchronisation of the operations of the drill machine, the resin injection device and the bolt introduction device. This can in turn be controlled by means of contactless sensors e.g., of an inductive type, arranged on the different movable elements and, effecting the operation of the valves of the hydraulic system. By the aid of a program it is possible completely to automate the successive introduction of the anchoring bolts accommodated in the magazine 60, six in the embodiment shown, cf. also the abovementioned Swedish patent application. During these automated operations operation personnel may be protected in the cabin of the drive vehicle 2 remote from the working area.

Realisation of the above briefly indicated hydraulic control system with position sensors and program work will be realised by an expert within the field.

Claims (12)

1. An assemblyforsecuring rock bolts, comprising a rock drilling machine, a resin injection device for injecting resin into a hole drilled by said drilling machine, and a bolt introducing device for introducing an anchoring bolt into said hole, the resin injection device including two conduits for separate but simultaneous feeding of resin and setting agent into the drill hole, and connected respectively, via pumps, to a resin container and a separate setting agent container.

2. An assembly according to Claim 1, in which the conduits are arranged to be forwardly feedable in the direction of their length on a feed rail.

3. An assembly according to Claim 1 or Claim 2 including a device for preheating the conduits and their contents before injection into the drill hole.

4. An assembly according to Claims 2 and 3, in which the preheating device is mounted on the fore end of the feed rail and is in the form of a guide tube with heating means.

5. An assembly according to any of the preceding claims, in which the conduits consist of two tubes arranged coaxially one in the other, the inner tube, the fore end of which protrudes slightly from the outer tube, being connected to the setting agent container, whereas the interspace between the tubes is connected to the resin container.

6. An assembly according to any of the preceding claims, in which the resin injection pump comprises a piston pump.

7. An assembly according to Claim 2, in which a hydraulic motor for forward feeding of the conduits, and two hydraulic drive motors for the resin injection and setting agent pumps, respectively, are connected into a common hydraulic control circuit for co-ordination and synchronisation of the operation of the three motors.

8. An assembly according to Claim 7, in which hydraulic motors for driving the rock drill machine and the bolt introducing device, are likewise included in the common hydraulic control circuit, contactless sensors for sensing the positions of the movable means included in the assembly controlling the valves in the common hydraulic circuit.

9. An assembly according to any one of the preceding claims in which the rock drilling machine, the conduits and the bolt introducing device are carried on a frame in the vicinity of a line of operation along which the operation steps are to be carried and through and into which they are introducable, a supporting means being arranged for engagement with the rock wall into which the drill hole shall be drilled, for keeping said frame in a fixed relationship to said wall, and a centering device for exact guidance of the drill rod, the conduits and the bolt into and along a common feed line is fixedly arranged with respect to said supporting means, at least for commencement of the operations.

10. An assembly according to Claim 9, in which the centering device is a guide funnel carried by said frame coaxially with said common feed line.

11. An assembly according to Claim 10, in which said funnel is longitudinally split, the parts thereof being outwardly movable.

12. An assembly for securing rock bolts substantially as specifically described herein.