AU2016308437B2

AU2016308437B2 - Actuator for a reactionless rock bolt tensioner

Info

Publication number: AU2016308437B2
Application number: AU2016308437A
Authority: AU
Inventors: Rual ABRUE
Original assignee: Epiroc Drilling Tools AB
Current assignee: Epiroc Drilling Tools AB
Priority date: 2015-08-18
Filing date: 2016-08-18
Publication date: 2021-02-04
Anticipated expiration: 2036-08-18
Also published as: WO2017031511A2; WO2017031511A3; ZA201800598B; AU2016308437A1; PE20180494A1

Abstract

The invention provides a hydraulically actuated wrenching apparatus which includes a socket shaft which includes a tubular shaft body which longitudinally extends between a first end, which is adapted to engage with a rotatable part of a rock anchor engaged tensioning device, and a second end, a gear mounted on the shaft body, a locking shaft at least partially housed within the tubular body which is locked against rotational motion, which is moveable longitudinally relatively to the shaft body and which is adapted, at a free end which is adjacent the shaft body first end, to engage with a non-rotatable part of the tensioning device, a hydraulic motor and a drive shaft which engages with the gear and which angularly displaces the gear when driven by the motor to cause the shaft body to rotate.

Description

ACTUATOR FOR A REACTIONLESS ROCK BOLT TENSIONER FIELD OF THE INVENTION

[0001] The invention relates to a hydraulically actuated wrench ¥/hich is adapted for use with a rock anchor engaged tensioning device,

BACKGROUND OF THE INVENTION

[0002] In the specification to a PCT patent application no. PCT/ZA2015/000052, which is herein incorporated by reference, a rock anchor assembly is described which includes a rock anchor which longitudinally extends between a leading end and a trailing end and to which a tensioning device is engaged at the trailing end. The tensioning device includes an outer member having a first end and a second end and a threaded passage which extends through the member between the ends and in inner member whic thraadedly engages with the threaded passage of the outer member.

[0003] A faceplate is then engaged with the rock anchor between the leading end and the tensioning device such that, in use, with the rock anchor inserted in a borehole and anchored therein, and the faceplate positioned against the rock face and the first end of the outer member abutting the faceplate, the outer member is rotatable relatively to the inner member to cause the inner member to move within the passage towards the second end of the outer member, drawing on the rock anchor body to place the body in tension.

[0004] The tensioning device, whilst providing a solution to tensioning a rock anchor, comes with its own technical challenges. The device has to be actuated „

2 within a confined space of the mine excavation, using a power source avasiable within the mine and the drive means has to be able to rotationaiiy drive the outer member whiist the inner member is iocked against rotation movement

[OOOSJ The invention at ieast partially solves the aforementioned problems,

SUMMARY OF INVENTION

[SODS] The invention provides a hydraulically actuated wrenching apparatus which includes a socket shaft which includes a tubular shaft body which longitudinally extends between a first end, which is adapted to engage with a rotatable pad of a rock anchor engaged tensioning device, and a second end, a gear mounted on the shaft body, a locking shaft at Ieast partially housed within the tubular body which is Iocked against rotational motion, which is moveable longitudinally relatively to the shaft body and which is adapted, at a free end which is adjacent the shaft body first end, to engage with a non-rofatabJe part of the tensioning device_s a hydraulic motor and a drive shaft which engages with the gear and which angularly displaces the gear when driven by the motor to cause the shaft body to rotate,

[ 00TJ The first end of the tubular shaft body may be adapted to provide a wrench socket into which the rotatable part is received,

[0008] The free end of the locking shaft may be adapted to be insertable into a receptacle of the non-rotatable part to prevent the non-rotatafole part from rotating with the rotatable part of the tensioning device

[O 0S] The apparatus may include a housing which houses the gear and to which the tubular shaft body is mounted through a bearing. „

3

[0010] The locking shaft may be engaged with the housing at an end opposed to the free end to iock the locking shaft against rotational movement,

[0011] The wrench socket may be hex shaped to mate with an outer nut-part of a cable anchor tensioning device.

[001 ] The free end may be adapted to engage with an inner screw-part of a cable anchor tensioning device.

[0013] The gear may be a worm gear,

£0014] The drive shaft may be a worm shaft.

BRiEF DESCRIPTION OF THE DRAWINGS

[0015] The invention is described with reference to the following drawings in which:

Figure 1 is an isometric exterior view of a hydrauiically actuated wrenching apparatus in accordance with the invention;

Figure 2 is an isometric longitudinally sectioned view of the wrenching apparatus of Figure 1 ;

Figure 3 is an Isometric view of a drive chain of the hydrauiicaily actuated wrenching apparatus;

Figure 4 Is an isometric transversely sectioned view of the wrenching apparatus; and

Figure 5 Is en sometric transversely sectioned view of the wrenching device, in use, engaged with a rock anchor tensioning apparatus. 4

DESCRIPTION OF PREFERRED EMBODIMENTS

[©016] With reference to Figures 1 to 4, a hydrauiically inflated wrenching apparatus 10 is described which accords with the invention. The apparatus is designed to apply torque to a rock anchor engaging tensioning device which is described in the specification to a PCT patent application no. PCT/ZA2015/000052, which is herein incorporated by reference. However, it is anticipated within the scope of the invention that the wrenching apparatus can be applied to any rock anchor or rock bolt similarly adapted with a tensioning device described in the PCT application to apply torque to the rock anchor or bolt and that the invention is not limited to application with a rock anchor.

[0017] The wrenching apparatus 10 includes a socket shaft 12 and a locking shaft 14, each of which are adapted to respectively engage an outer nut-part 4 and an inner screw-part 6 of a tensioning devioe 7 engaged with a rock anchor 8 (see Figure 5).

[0018] The apparatus 10 includes a drive chain 16 (see Figure 3) which causes the socket shaft 12 to axially rotate to turn the outer nut-part 4 of the tensioning device 7 when engaged thereto. The drive chain includes a worm gear 18 which is mounted to the socket shaft, a hydraulic motor 20 and a worm shaft 22 which engages the gear and transmits rotational drive to the gear. A disc-shaped gearbox casing 24 completes the apparatus 10 in which, at least, the gear is housed.

|0 19] The socket shaft 12 has a tubular shaft body 28, which longitudinally extends between a first end 28 and a second end 30, disposed perpendicularly to the plane of the drive chain. At the first end, the body flares into a wrench socket 32. The „

5 wrench socket is internally shaped to mate with the shape of the nut-part of the tensioning device, for example hex-shaped.

[0020] The worm gear 18 engages wiih the shaft body 22 towards its second end 30. From the shaft, the gear radially and laterally extends to terminate at a perimeter edge 34 into which a plurality of gear teeth 38 are cut or formed. On either side of the location of attachment of the gear to the shaft body, support bearings (38A and 3SB) are located, engaged with the shaft body and internally mounted with the casing 22,

[0021] The locking shaft 14 is housed in the tubular body 22 of the socket shaft 12 and projects from both ends of the body_f terminating in a locked end 40 and a free end 42, The locked end extends through the casing 22 as illustrated in Figure 1 and passes through an aperture 44 in a reaction plate 48, The aperture is complementary shaped to the cross sectional shape of the shaft 14, which has a plurality of longitudinal splines 47 on its outer surface, thus preventing the locking shaft from rotating when the socket shaft rotates but allowing for movement in the longitudinal direction for the reason described below. f0022] The hydraulic motor 20 Is located exteriorly of the casing 24 but is in drive communication with the internally located gear 18 by means of the worm shaft 22 which is engaged with the motor and which penetrates the casing to present a helical spline 48 in meshed engagement with the gear teeth 34.

[0023] The hydraulic motor is connectabie to a hydraulic fluid source (not shown) to receive a hydraulic fiusd input info the motor which convents hydraulic pressure flow into torque which is transmitted down the drive chain 18 to the socket shaft 12. if the socket shaft 12 is engaged with the tensioning device 2, torque will be imparted on the outer nut-part 4 of the device to cause the rock anchor 8 to which the tensioning device is attached to be placed sn tension within a rock hole (see Figure 5),

[0024] The inner screw-part 6 of the tensioning device 7 is held against rotation by engagement with the free end 42 of the locking shaft 14. The free end 42 is adapted to mate with the screw-part by partial insertion as illustrated in Figure 5. fOQ2S] To accommodate the movement of the inner screw-part relatively to the outer outer-part in an axial direction (represented by a directional arrow in Figure 5) of the rock anchor, the locking shaft is moveable longitudinally within the shaft body 28.

[002S] The wrenching apparatus 10 can be used as a hands-free device which, when engaged with the tensioning device 7, can be adapted to hang from the device, freeing the operator to perform other functions. The apparatus can aiso be attached to a telescopic air-leg or mounted onto a boom of a mechanical bolt installation machine.

Claims

CL S

1 , A hydraulicaliy actuated wrenching apparatus which includes a socket shaft hsch includes a tubular shaft body which longitudinally extends between a first end, which is adapted to engage a rotable part of a rock anchor engaged tensioning device, and a second end; a gear mounted on the shaft body; a locking shaft at least partially housed within the tubular body, which is locked against rotational motion, which is moveable longitudinally relatively to the shaft body and which is adapted, at a free end which is adjacent the shaft body first end, to engage with a non-rotatable pari of the tensioning device; a hydraulic motor and a drive shaft which engages with the gear and which angularly displaces the gear when driven by the motor to cause the shaft body to rotate,
2. A hydrauiicaliy actuated wrenching apparatus according to claim 1 wherein the first end of the tubular shaft body is adapted to provide a wrench socket into which the rotatable part is received.
3. A hydraulicaliy actuated wrenching apparatus according to claim 1 or 2 wherein the free end of the locking shaft is adapted to be insertabie into a receptade of the non-rotatable part to prevent the non-rotatable part from rotating with the rotatable part of the tensioning device,
4. A hydraulicaliy actuated wrenching apparatus according to any one of claims 1 to 3 which includes a housing which houses the gear and to which the tubular shaft body is mounted through a bearing. 5, A hydraufeayy actuated wrenching apparatus according to claim 4 wherein the locking shaft is engaged with the housing at an end opposed to the free end to lock the locking shaft against rotational movement.

6, A hydraulicaiiy actuated wrenching apparatus according to any one of claims 1 to 5 wherein the gear ss a worm gear,

7, A hydrauiically actuated wrenching apparatus according to claim 8 wherein the drive shaft is a worm shaft.