DRIVER SOCKET FOR INSTALLATION OF A GROUND REINFORCEMENT BOLT

Abstract

A driver socket for installation of a ground reinforcement bolt is provided. The driver socket includes a cylindrical tube having a longitudinal axis, wherein a leading end of the driver socket is configured to be arranged in connection to the bolt and a trailing end of the driver socket is configured to be arranged in connection to a driving device. The driver socket includes a through hole having. The through hole has a varying cross-sectional area along its axial length. The through hole has comprising a first diameter in a mid-section thereof that is smaller than a second diameter in a leading section thereof. The through hole has a transition located between the mid-section and the leading section. The transition has a frustoconical shape. An installation system including a ground reinforcement bolt and the driver socket is also provided.

Claims

1. A driver socket for installation of a ground reinforcement bolt, the driver socket comprising: a cylindrical tube having a longitudinal axis, wherein a leading end of the driver socket is configured to be arranged in connection to the bolt and a trailing end of the driver socket is configured to be arranged in connection to a driving device and a through hole having an axial length, wherein the through hole along its axial length has a cross-sectional area including a first diameter (D1) in a mid-section and a second diameter (D2) in the leading section, the first diameter being smaller than the second diameter, and wherein the through hole includes a leading section and a mid-section and a transition located between the mid-section and the leading section, the transition having a frustoconical shape.

2. The driver socket as claimed in claim 1, wherein a plane of the transition defines an angle (?) in relation to the longitudinal axis, wherein the angle (?) is in a range of 30? to 60?.

3. The driver socket as claimed in claim 2, wherein the angle (?) is in the range of 40? to 50?.

4. The driver socket as claimed in claim 3, wherein the angle (?) is 45?.

5. The driver socket as claimed in claim 1, wherein a diameter ratio (D1/D2) between the mid-section and the leading section is ?.

6. The driver socket as claimed in claim 1, wherein the diameter ratio (D1/D2) between the mid-section and the leading section is ?.

7. The driver socket as claimed in claim 1, further comprising an outside diameter being 60 mm.

8. An installation system comprising: a ground reinforcement bolt; and a driver socket according to claim 1, wherein the bolt is a mechanical friction bolt.

9. The installation system according to claim 8, wherein the bolt includes a nut at a trailing end, and wherein the nut includes a display face with indicia at an annular end.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0020] A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0021] FIG. 1 is an external perspective view of a driver socket;

[0022] FIG. 2 is a cross-sectional perspective view of a driver socket;

[0023] FIG. 3 is an enlarged cross-sectional perspective view of a driver socket;

[0024] FIG. 4 is a side view showing the force transmittal in a driver socket and a rock bolt.

DETAILED DESCRIPTION

[0025] FIG. 1 discloses a driver socket according to a first embodiment and its use together with a mining machine will hereinafter be described with reference to the appended drawings. The driver socket 1 is used for installation of a ground reinforcement bolt in order to secure adequate ground support underground. When the bolt is inserted into the hole the driver socket 1 is rotated in order to complete the full engagement of the bolt in the formation. The driver socket 1 has an outside diameter D3 typically being 50, 60 or 70 mm.

[0026] Referring to FIG. 2, the driver socket 1 is disclosed to be orientated along a longitudinal axis A. The driver socket 1 has a leading end 10 that is intended to be arranged in connection to a rock bolt, and a trailing end 20 that is intended to be arranged in connection to a driving device. The driver socket 1 comprises a cylindrical tube 2 with a through hole having different sections comprising specific diameters, respectively. The through hole has a varying contour along its length. A mid-section 3 has a first diameter D1 of the cross-sectional area. At the leading end 10 there is a leading section 13 with a second diameter D2, which leading section 13 is chosen to fit the rock bolt nut. At the trailing end 20 there is a trailing section 23, which trailing section 23 is chosen to threadably engage with the driving device. The mid-section 3 has a longer longitudinal length then the leading section 13 and the trailing section 23 of the driver socket.

[0027] The mid-section 3 has the smallest diameter of the three sections. The value of diameter D1 is half of the value of diameter D2. The value of diameter D1 could also be one fourth of the value of diameter D2 or one fifth.

[0028] Between the mid-section 3 and the leading section 13 there is a transition 11. This is an intersection where the two sections meet. It is an inclined plane.

[0029] In FIG. 3 the leading end 10 with the leading section is shown. The transition 11 with its inclined plane is defined to have a specific angle ? in relation to the longitudinal axis A. This angle is an acute angle that should be well balanced, so it is not close to 90? nor close to 0?. A relevant value of the angle is somewhere in the range of 30? to 60?, more preferably 40?, 45? or 50?. This bevel gives a concentric fit around the nut.

[0030] FIG. 4 discloses the leading end 10 with the leading section fitted around a ground reinforcement bolt 100. During hammering the driver socket moves slightly back and forward, so it can be said to rattle back and forth.

[0031] The upper part of the figure shows the situation when the hammering starts. This is before the bolt 100 gets into contact with the transition 11. The forces represented by arrows are shown to be transmitted purely in an axial longitudinal direction along the driver socket and the rock bolt.

[0032] The lower part of the figure shows the situation when the driver socket moves forward, in which situation the hammering continues. So, the bolt hits the leading end 10 of the socket and the transition 11 thus makes contact with the bolt. The forces will then be distributed so that they also comprise a radial component in addition to the axial forces. This is represented in the lower part of FIG. 4 by the resultant force arrows shown in connection to the transition 11, which resultant force arrows being perpendicular to the transition 11.

[0033] While hammering in the rock bolt the driver socket's leading end 10 alternates between the backward position shown in the upper part of FIG. 4 and the forward position shown in the lower part of FIG. 4.