Mining or in situ disintegration of hard material – Cutter tooth or tooth head – Wear shield or replaceable wear sleeve
Patent
1996-08-30
1998-04-14
Bagnell, David J.
Mining or in situ disintegration of hard material
Cutter tooth or tooth head
Wear shield or replaceable wear sleeve
299106, E21C 35197
Patent
active
057384150
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a pick box and liner sleeve combination, adapted to receive the shank of a replaceable, mineral cutter pick, and to a mineral cutter drum provided with such a pick box, as are used extensively in mineral mining operations, in tunnelling operations, in quarrying operations, and in so-called road planing operations.
It is known to insert a replaceable liner sleeve (also known as an adaptor) into a circular section aperture of a pick box, into which liner sleeve is fitted the shank of the pick, so that the sleeve is interposed between the aperture of the pick box and the shank of the pick. The advantage of a liner sleeve is that in-service wear (which occurs due to pick and/or sleeve rotation and impaction) is inflicted on the liner sleeve rather than the box, because when wear has occurred to such an extent that a pick shank cannot be retained satisfactorily, the worn sleeve may be removed and replaced by a fresh sleeve, which avoids the need to remove the associated cutting drum to a safe zone of a mine, or even out of the mine, so that a damaged pick box may be removed and a fresh pick box welded in place. Furthermore, sleeve removal may be necessary not because the sleeve is damaged, but because a pick has been broken off, and its shank remains in the sleeve.
Ideally, the sleeve should be a non-rotating, and hence tight, fit to minimise premature wear, but difficulties are however encountered in removing "tight" liner sleeves, as these have usually been firmly impacted in the aperture of the pick box due to loading which occur in service. Thus, currently, miners are obliged to employ tools such as screw-jacks and/or hydraulic jack for insitu removal of a tight sleeve, assuming the box is of open construction, whereby the rear of the sleeve is exposed and hence engageable by the screw-jack. Screw-jack operation in the confines of a mineral face on a rotary cutter drum provided with say 50 picks, is an awkward and time consuming operation, with loss of mineral production until the cutter drum is ready for service. With a closed box, screw-jack removal is impossible. Frequently, sleeve extraction difficulties, which difficulties themselves sometimes lead to the need to remove the cutting drum from the mining machine to a safe area, or even out of the mine, for the burning-off of pick boxes that house liner sleeves that cannot be extracted--the very action that the use of a liner sleeve seeks to avoid. Hence, an alternative option has been to provide loose-fit liner sleeves and to accept the disadvantages of premature wear.
Sleeve extraction has been a long recognised problem with, to date, no satisfactory solution. Thus, in 1979, in DE 2915510, the VOEST company proposed the introduction of a lubricant being the outer periphery of a sleeve of constant external diameter and the sleeve-receiving bore of the pick box.
In contrast to the constant diameter sleeve of VOEST, a stepped sleeve positively retained mechanically in the sleeve-receiving bore of the pick box by a roll pin is described in U.S. Pat. No. 4,678,238 of the Fansteel but Applicants are unaware whether the Fansteel system has ever been used in service. In the Fansteel system, which addresses the problem of pick cooling to minimise metallurgical damage--as the picks frequently "glow" in action with a tendency for spontaneous methane ignition in coal mining--and also to wash dust and debris away from the pick by used cooling water existing as a spray from an outlet bore of the sleeve.
A basic object of the present invention is to provide a pick box and sleeve combination, in which the sleeve can be readily and quickly removed, e.g. whilst located at an underground mineral face.
According to a first aspect of the present invention there is provided a pick box and sleeve combination comprising; use, to receive the shank of a mineral cutter pick; of the sleeve and the aperture; and and in fluid flow communication with the zone of differential area, whereby upon admission of hydraulic fluid under sufficient pressure to the zon
REFERENCES:
patent: 4678238 (1987-07-01), Emmerich
patent: 5498069 (1996-03-01), Siebenhofer et al.
Bagnell David J.
Minnovation Limited
LandOfFree
Pick holder and fixing sleeve for an extraction machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pick holder and fixing sleeve for an extraction machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pick holder and fixing sleeve for an extraction machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-629705