Rotary cutting head with water supply

A rotary cutting head (1) for a mineral mining machine, comprises a drive shaft (5) carrying a central drum (4), and beyond each end of the central drum (4), an outer drum (2,3), each drum being provided with an array of pick boxes (7) to receive an individual pick (8), wherein the drive shaft (5) has a longitudinal bore (10) housing at least one water conveying tube (11), which together with a network of bores (25) enable a single water admission cartridge interposed between an outer end of one of the drums (2), and an end face plate (16) of that drum (2) to supply water to all three drums (2, 3, 4).

This application claims priority with respect to British Application No. 0200880.3, filed Jan. 16, 2002.

FIELD OF THE INVENTION

This invention relates to a rotary cutting head for a mining or tunnelling machine, and to a machine provided with such a cutting head.

BACKGROUND OF THE INVENTION

In GB 2297989, is described a so-called continuous miner, in which the hitherto “dry” rotary cutting head, comprising a drive shaft carrying a centre drum and two, co-axial outer drums, is provided with a safe supply of pressurised water whereby, if and when a water leak occurs, there is no leakage eg into a gear box, but only to an exterior part of the cutting head, and hence onto the mine floor. It was envisaged in GB 2297989 that each of the three drums would have its own individual water feed by a cartridge unit. This system has been used in practice and has had some degree of success. Inevitably, rotary water seals wear requiring the dismantling or changing of the cartridges, but the changing of the central cartridge, which by necessity was constructed in two halves and built around the central drum, was a long labourious procedure.

An advantage of the original three-cartridge system was the phasing of the water on the heads. This was threefold:to reduce the amount of water used;to prevent the machine operator from getting wet; andto encourage the movement of fresh air into a cut zone.

OBJECT OF THE INVENTION

A basic object of the invention is the provision of an improved rotary cutting head of the kind described in GB 2297989, and mining machine incorporating such a cutting head.

SUMMARY OF A FIRST ASPECT OF THE INVENTION

According to a first aspect of the invention, there is provided a rotary cutting head for a mineral mining machine, the head comprising a drive shaft carrying a central drum, and beyond each end of the central drum, an outer drum, each drum being provided with an array of pick boxes to receive an individual pick, wherein the drive shaft has a longitudinal bore housing at least one water conveying tube, which together with a network of bores enable a single water admission cartridge interposed between an outer end of one of the drums, and an end face plate of that drum to supply water to all three drums.

SUMMARY OF A SECOND ASPECT OF THE INVENTION

According to a second aspect of the invention, there is provided a mineral mining machine incorporating a rotary cutting head in accordance with the first aspect.

ADVANTAGES OF THE INVENTION

By means of the invention, the presence in the prior art of GB 2297989 of a central cartridge is avoided, with the single cartridge employed being in a readily accessible location, with the design and construction of the single cartridge being such, that it has the capacity to feed water to the entire cutter head.

PREFERRED OR OPTIONAL FEATURES OF THE INVENTION

Preferably multiple water conveying tubes are employed.

Preferably four water conveying tubes are employed.

The main drive shaft is bored to give a connection to all three drums. It is then a relatively simple matter to make a non-rotating water seal between all three drums and the drive shaft.

At least the four water conveying tubes are adapted to provide a phased supply of water, such that only a selected sector of drum is supplied with water, not only providing for more economical use of pressurised water, but also avoiding the soaking of the machine operator or other personnel in the vicinity.

In detail, if the water feed cartridge is located at the right hand head, then the four tubes provide a phased water supply to the left hand head along the longitudinal bore of the drive shaft.

The water supply to the central head may or may not be phased.

The rotary cutting head1in accordance with the invention comprises three co-axial drums, being a right hand outer drum2, a left hand outer drum3, and a central drum4, the drums2,3and4being secured on a common drive shaft5, which is supported, in the well-known manner, from a pair of spaced-apart support arms projecting forwardly from a so-called continuous mining machine, the support arms housing a power drive train to the drive shaft5, and being pivotally attached to the machine under the control of hydraulic rams to raise or lower the head1, as dictated by mining requirements. The support arms penetrate the gaps6between each end of the central drum4, and the adjacent ends of the left hand, and right hand, drums3,2. For clarity, onlyFIGS. 1,3and4indicate pick boxes7that are welded at selected locations in a helical array around the drums2,3and4, each pick box being provided with a replaceable pick8.

For a variety of well known reasons, water sprays are required and one spray nozzle9is usually associated with each pick box7, but there exists the problem of introducing a water supply from a static supply pipe into a rotating cutting head1. A solution for achieving water introduction, which avoids collateral damage to drive gears etc upon the inevitable failure of a water seal of the cutting head is described in GB 2297989/PCT/GB94/02518. When the rotary seal of this system fails, water falls harmlessly onto the mine floor.

The present invention is a refinement of this system, in that the drive shaft5has a central bore10provided with four water delivery tubes11to convey water from the right hand drum2to a distribution plate12attached to the left hand drum3, and in the rotary cutting head1is provided a single water introduction cartridge14, which is trapped between a square drive extension member15secured by bolts to adjacent end of the right hand drum2, and an end face plate16secured by bolts17to the member15, the cartridge14in turn being secured by bolts to the member15.

The member15is closed off by a cover18secured by bolts19and outer protection rings20embrace the cartridge14. A static three piece ring21has lip seals22engaging adjacent faces of the rings20. A static and radially extending water feed arm23extends through the ring21. From the arm23, water is supplied to a water distribution network of the cutting head1, comprising bores24supplying the right hand drum2, and two axially extending pipes25,27, supplied by bores26. Pipe25supplies the central bore10and pipe27supplies the tube11. From one or other of the tubes11, water may readily be conveyed to the left hand drum4via distribution plate12.

In accordance with the invention, the one cartridge14only serves to introduce water from a static supply source23to all three rotating drums2,3and4. Consequently, compared with GB 2297989, the number of high pressure seals (not shown) that can, and will fail or wear out, is reduced from three pairs to one pair. However, even when the one pair of high pressure seals either fails, or require scheduled replacement, the sole cartridge14is provided in a readily accessible location to enable repair or maintenance work to be effected with minimal down time.