WO2004085113A1

WO2004085113A1 - An arrangement for adjusting the setting of a grinding machine

Info

Publication number: WO2004085113A1
Application number: PCT/SE2004/000284
Authority: WO
Inventors: Hans Lindgren
Original assignee: Atlas Copco Secoroc Ab
Priority date: 2003-03-10
Filing date: 2004-03-02
Publication date: 2004-10-07
Also published as: SE0300635D0

Abstract

An arrangement for adjusting the setting of a machine for grinding drill bits (6), wherein the machine includes a grinding arrangement (3) which can be displaced in the horizontal plane to enable it to be centred above a button bit (8) in the drill bit (6) to be ground. The grinding arrangement (3) is mounted in a bracket structure (4) that is carried by a fixedly mounted carrier arm (2) in a manner such as to enable the bracket structure (4) to be displaced in the horizontal plane in relation to the carrier arm (2); and in that locking devices (22) are provided for locking the bracket structure (4) in relation to the carrier arm (2) in a selected position.

Description

AN ARRANGEMENT FOR ADJUSTING THE SETTING OF A GRINDING MACHINE

The present invention relates to an arrangement for adjusting "he setting of a grinding machine, and more specifically to "he setting of a back-carried grinding machine for grinding or honing drill bits.

Drill bits are subjected to a great deal of wear and must be well-honed in order to drill effectively in rock. Bits that are poorly sharpened do not only impair the efficacy of rock drilling, but also cause the drill string and the drilling rig to be subjected to a great deal of stress and strain and also wear.

There is therefore a great need for grinding, honing, button bits at regular intervals. There exist to this end special semi-automatic grinding machines for grinding the button bits and also for grinding down the steel included in the drill bit, at the same time. Transportable grinding machines that enable the button bit to be ground at the site where drilling ^~akes place are also available commercially. These machines may be semi-automatic machines or manually operated machines and are exclusively of the type that use grinding cups.

Consequently, there has been developed a grinding machine of "he aforesaid kind that can function at least serni- automatically and that can be mounted on a drilling rig or on a separate readily transportable device. This grinding ma- chine is the subject of a separate patent application filed at the same time as the instant application. One difficulty "o be solved in respect of such grinding machines is the ability to centre and lock the machine firmly over the button bits to be ground, in a simple fashion. Accordingly, an object of the present invention is to provide an arrangement for adjusting the setting of a grinding machine by means of which the grinding machine can be positioned in relation to the button bit to be ground and locked fii ly in said position in a simple fashion.

This object is achieved with an arrangement for adjusting the setting of a button bit grinding machine which comprises a grinding arrangement which is mounted for displacement in the horizontal plane so that it can be centred above the button bits in the drill bit crown to be ground. According to the invention, the grinding arrangement is mounted in a bracket structure that is carried by a fixedly mounted carrier arm such as to enable the bracket structure to be displaced rela.ive to the carrier arm in the horizontal plane, wherein the grinding arrangement includes means for locking the bracket structure firmly m relation to the carrier arm in any selected position.

The invention will now be described in more detail with reference to a non-limiting exemplifying embodiment and also with reference to the accompanying drawings, in which Fig. 1 LS a side view of the grinding machine in an adjusted set- zing, in which the grinding wheel is centred about a button bit of a drill bit crown, and shows the grinding machine provided with an arrangement for adjusting the setting of said machine in accordance with the invention; Fig. 2 is a front view of he grinding machine; Fig. 3 illustrates a part A of the Fig. 2 illustration; and Fig. 4 is a sectional view zaken on the line B-B in Fig. 2.

The grinding machine illustrated in the accompanying drawings Is intended to be mounted on a drilling rig and includes a carrier frame 1 intended for fastening to a drilling rig, not shown. The frame 1 has an upper, outwardly projecting carrier arm 2 which carries the grinding arrangement 3 of said grinding machine via a bracket structure 4 that can be displaced in the horizontal plane. The grinding arrangement 3 can be raised and lowered in the bracket structure 4, i.e. can be displaced in the vertical plane. The frame 1 also includes a holder arm 5 which is located beneath the grinding arrangement and adapted to hold firmly a drill bit crown 6. The drill bit crown β can be readily fitted to and locked in the holder aim 5, with the aid of a locking lever 7. The crown 6 includes a number of button bits 8. The number of button bits 3 included, and their size and placement on the crown 6, may vary. The crown may also be locked obliquely in the holder arm 5, to enable correct grinding of the peripheral button bits 8a in the drill bit crown 6.

The grinding arrangement 3 includes a grinding unit 9 which, in turn, includes a motor 10, a spindle 11 and a grinding wheel 12 carried on the end of the spindle 11. The grinding unit 9 is fitted so that the spindle will slope slightly in relation to the horizontal plane, wherein the grinding wheel L2 rotates about said spindle. The grinding wheel 12 is of a <no n type and is provided with a diamond coating and may be designed for grinding spherical or ballistic button bits, The grinding unit 9 is carried by an arm 13 on the grinding arrangement and can be swung about a generally vertical shaft L4 with the aid of a pivot cylinder 15 which is adapted to swing the grinding unit 9 forwards and backwards between the positions shown in Figs. 3 and 4, i.e. with a pendulum move- ment of about 180°, preferably slightly greater than 180°. The shaft 14 is arranged so that an extension of he shaft will pass through the centre of the grinding disc 12 and so that as the grinding unit 9 swings forwards and backwards the grinding wheel will move about a point which corresponds to -he top of one of the button bits 8 when the grinding arrangement 3 is correctly adjusted. The geometric axis about which the grinding unit 9 moves forwards and backwards is a generally vertical axis which coincides with the geometric centre axis of the button bit 8 when the grinding arrangement 3 has been correctly adjusted in relation to the button bit 8. The grinding unit 9 thus moves forwards and backwards in a pendulum movement in the horizontal plane, so as to be able -o grind or hone a button bit 8 that extends generally vertically on the grinding occasion concerned.

Adjustment to the setting of the grinding arrangement 3 is achieved with the aid of a centring body 16 which can be placed and centred over a button bit 8, as shown in Fig. 1. En this position, the centring body is located in the extension of the shaft 14 and on the geometric axis about which ^~he grinding unit 9 is intended to swing. When the grinding arrangement 3 has been centred over a button bit in this way, ^~he arrangement 3 is locked against movement in the horizon- -al plane and can then be solely raised and lowered.

The bracket structure 4 in which the grinding arrangement 3 is mounted is connected to the carrier arm 2 via the intermediate coupling of a carrier plate 19. A first array of linear bearings 20 is provided between the carrier plate 19 and the carrier arm 2, while a second array of linear bearings 21 is provided between the carrier plate 19 and the bracket structure 4. The first array of linear bearings 20 is disposed at right angles to the second array of linear bearings 21, -hereby enabling the bracket structure 4 and the grinding arrangement 3 carried thereby to be moved selectively in the horizontal plane, although naturally within applicable outer limits . The grinding arrangement 3 includes an operating lever 17 with which the grinding arrangement can be moved in the horizontal plane to a correct position for adjusting the setting of the machine with the aid of the centring cup 16.

However, before grinding can take place, it is necessary that ^~he grinding arrangement 3 can be locked firmly in the position set in the horizontal plane. Locking devices 22 are provided to this end between the bracket structure 4 and the carrier plate 19 and also between the carrier arm 2 and the carrier plate 19. The illustrated locking devices 22 are pneumatic piston-cylinder devices whose pistons are adapted IO project out and press against the carrier plate 19 so that said plate will no longer be able to move, therewith locking ,:he grinding arrangement 3 firmly in its set position. Located in connection with the operating lever 17 is a control means 18 by means of which the piston-cylinder devices 22 can be activated/released. The control means 18 are preferably adapted to release the locking means in response to operation of the control means 18, and to release the locking means immediately the control means 18 are released. The pneumatic connections 23 for driving the piston-cylinder devices are shown in the drawings .

Et will be understood that the locking means 22 may have forms other than said piston cylinder devices, for instance the form of electromagnets when the carrier plate 19 is comprised of magnetic material.

The locking capacity between the locking means 22 and the carrier plate 19 can be enhanced by providing the locking means and/or the carrier plate with a friction enhancing surface, for example with the aid of a rubber fabric or some other friction-enhancing covering. As before mentioned, a grinding machine that includes the machine setting arrangement according to the invention is suitably moun eo on a drilling rig and supplied with appro- priate operating power, electrical, pneumatic or hydraulic pov/er, and water from the drilling rig. This supply also applies, of course, to the supply of power to the locking devices 22. Alternatively, the grinding machine and said setting arrangement may, of course, be mounted on an own transportable device, for instance a wagon or carriage, although this will require additional external power supply of electricity, air or hydraulic medium for driving the grinding machine and the locking devices. A grinding machine that includes the setting arrangement in accordance with the in- vention may, of course, also be used conveniently in a fixed unit in a workshop environment .

Claims

I. An arrangement for adjusting the setting of a machine for grinding drill bits (6), wherein the machine in- eludes a grinding arrangement (3) which can be displaced in -he horizontal plane to enable it to be centred above a button bit (8) in the drill bit (β) to be ground, characterised in that the grinding arrangement (3) is mounted in a bracket structure (4) that is carried by a fixedly mounted carrier arm (2) in a manner such as to enable the bracket structure (4) to be displaced in the horizontal plane in relation to ^~he carrier arm (2); and in that locking devices (22) are provided for locking the bracket structure (4) in relation to nhe carrier arm (2) in a selected position.

2 . A setting arrangement according to Claim 1, characterised in that the bracket structure (4) is connected to the carrier arm (2) via the intermediate coupling of a carrier plate (19) .

3. A setting arrangement according to Claim 2, characterised by a first array of linear bearings (20) disposed between the carrier plate (19) and the carrier arm (2), and by a second array of linear bearings (21) disposed between :he carrier plate (19) and the bracket structure (4), wherein he first array of linear bearings (20) is disposed at right angles tc the second array of linear bearings (21) .

4. A setting arrangement according to Claim 2 or 3, characterised in that the locking devices (22) are disposed between the bracket structure (4) and the carrier plate (19) and also between the carrier arm (2) and the carrier plate (19) .

5. A setting arrangement according to Claim 4, characterised in that the locking devices (22) are adapted to press against the carrier plate (19) .

6. A setting arrangement according to Claim 5, characterised in that the locking devices (22) are pneumatic piston-cylinder devices.

7. A setting arrangement according to Claim 5, charac- terised in that the locking devices (22) are electromagnets; and in that the carrier plate (19) is comprised of magnetic material .

8. A setting arrangement according to any one of the preceding Claims, characterised in that the operating lever

(17) is adcipted to displace the grinding arrangement (3) in the horizontal plane.

9. A setting arrangement according to Claim 8, charac- terised in that activating devices (18) for manoeuvring the locking devices (22) are arranged in connection with the operating lever (17) .

10. A setting arrangement according to any one of Claims 4-9, characterised in that the locking devices (22) and/or the carrier plate (19) is/are provided with a friction enhancing surface.