Bearings – Rotary bearing – Antifriction bearing
Patent
1996-06-07
1998-08-18
Hannon, Thomas R.
Bearings
Rotary bearing
Antifriction bearing
173149, 173216, 175170, E21C 110
Patent
active
057950792
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a shaft bearing in a rock and ground-drilling machine which includes a gear housing in which there is journalled a shaft which embraces a drill string in the manner of a sleeve and which is secured to the shaft with the aid of a chuck connected thereto, wherein the chuck is manoeuvred by means of pressure fluid which is delivered to the chuck through the medium of a commutator which acts between the gear housing and the shaft.
A shaft bearing of this kind is known, for instance, from SE 324 747. In the case of this known shaft bearing, the drill shaft is journalled in at least two journal bearings. This requires accurate manufacture with regard to the angular correctness and the concentricity between the bearing positions. In addition, when the gear housing is comprised of two parts, these parts must be made to match one another and must therefore be sold in pairs as spare parts and must not be mixed together when several gear housings are repaired at one and the same time. Despite this matching of the gear housing parts, it is necessary to expect some deviation from a perfect form and from perfect measurement tolerances, and it is therefore necessary to provide the journal bearings with a certain clearance.
The object of the present invention is to eliminate the aforesaid problems and to provide a shaft bearing which will enable the shaft to adjust freely in the bearing without jamming or binding therein. In the case of impact drilling, or hammer drilling, it is also an advantage when the journal bearing is completely free of any play, or when the bearing is pre-stressed. This object is achieved with a shaft bearing according to claim 1. The depending Claims define suitable embodiments that further assist in achieving this solution.
The invention will now be described in more detail with reference to the accompanying drawings, in which
FIG. 1 is a side view, partly in section, of a rock and ground-drilling machine which includes an inventive shaft bearing;
FIG. 2 is a sectional view of the drill gear-housing, taken on the line 2--2 in FIG. 1; and
FIG. 3 is an enlarged view of part of FIG. 2.
The drill illustrated in FIG. 1 includes a feed bar 11 which is supported in rock by expansion bolts 12. It will be understood, however, that the feed bar 11 may be supported in some other way, for instance by means of a wheeled carriage. The drilling machine also includes a gear housing 14 which is supported by a slide 13 which can be moved along the feed beam 11 with the aid of chains 15, 16, and a drive motor in the form of a piston-cylinder device 17, which includes two delivery lines 18, 19. When pressure fluid is delivered through the delivery line 18, the piston rod 20 is moved upwards in FIG. 1 and the chain 16 will pull the slide 13 downwards in FIG. 1. When pressure fluid is delivered through the line 19 instead, the slide 13 will be pulled upwards by the chains 15.
The front end of the feed beam 11 carries a chuck 21 which functions to grip and release a drill string, for instance a drill tube 23. The drill string 23 is comprised of a plurality of drill string elements, i.e. tube sections which are mutually screwed together, and a drill bit 26. In the case of rock drilling, the drill bit 26 may have the form of a tubular diamond drill bit and the first tube section may have the form of a so-called core tube for collecting drill core. The machine also includes a water swivel 24, for delivering rinsing water to the drill tube.
A chuck 27 for transferring rotational and axial movements to the drill string 23 is mounted beneath the gear housing 14. This chuck accompanies the gear housing 14 as it moves axially.
FIG. 2 is a longitudinal sectioned view of the gear housing. The illustrated housing 14 is comprised of two parts, an upper gear-accommodating part 28 and a lower part 29, said parts being joined together by means of a screw assembly 30. The actual tubular drill shaft 31 is journalled in the gear housing 14. A gear wheel 32 is secured to the shaft 31 by means of a screw j
REFERENCES:
patent: 2904938 (1959-09-01), Bassoff
patent: 3613804 (1971-10-01), Jonsson
patent: 4637477 (1987-01-01), Jonsson
patent: 4643262 (1987-02-01), Jonsson
patent: 4877094 (1989-10-01), Ebeling
Jonsson Gunnar
Nordqvist Ulf
Atlas Copco Craelius AB
Hannon Thomas R.
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