Rotary Cutter For Mining With Fluid Supply Chambers

Abstract

A rotary cutter head for a mineral mining machine, has a hub for mounting on a driven machine shaft, a drum secured around the hub and cutter tool holders secured around the drum, the head being provided with a plurality of angularly arranged chambers for dust suppression fluid, each extending axially along the inner periphery of the drum and arranged to feed fluid from a distribution unit adjacent to the hub towards the cutting zone of the head.

Description

This invention relates to rotary cutters for mineral mining machines and in particular to such cutters which are provided with means for feeding dust suppression fluid into the cutting zone.

A rotary cutter has been proposed which comprises a hub, a cylindrical component secured co-axially around the hub, and two loading vanes for cut mineral secured helically around the outer periphery of the component, and which further comprises means for feeding dust suppression fluid from a hollow drive shaft upon which the hub is mounted to the radial edges of the vanes. These means comprise a distributor in the form of a `T` piece, two flexible pipes leading from the ends of the `T` piece to two further pipes which follow helically along the bases of the vanes around the outer periphery of the component. A plurality of radial pipes feed the fluid from the helical pipes to the radial edges of the vanes.

Such a known cutter has the disadvantage that the two flexible and two helical pipes are unable to pass sufficient fluid to feed the plurality of radial pipes. Thus the radial pipes which are most remote from the flexible pipes receive little or no fluid and soon become blocked with fine particles of cut mineral. Also, as the pipes extend helically around the component they are long and the fluid is subject to a large pressure drop and this often results in an insufficient amount of fluid being fed to the cutting zone to suppress the dust efficiently.

It has also been proposed to feed dust suppression fluid to only the segment of the cutter which is cutting mineral. As the cutter rotates the fluid is fed in sequence to the segments of the cutter in the cutting zone. A further disadvantage of the above mentioned cutter is that as the pipes extend helically around the component it is not possible to feed fluid to only one segment of the cutter. It is also not possible with this known cutter to feed fluid to the segments in sequence.

Other known rotary cutters have been proposed comprising a hollow cylindrical component but such cutters have the disadvantage that apart from not lending themselves to the feeding of fluid to only one segment of the cutter, hollow components are difficult and expensive to manufacture.

An object of the present invention is to provide a rotary cutter which is provided with means for feeding dust suppression fluid into the cutting zone and which overcomes the above mentioned disadvantages.

It is also an object of the invention to provide a relatively inexpensive and reliable cutter.

According to the present invention a rotary cutter for a mineral mining machine, comprises a hub adapted to be mounted on a driven shaft of the machine, a cylindrical component secured co-axially around the hub, cutter tool holders secured around the component, a plurality of elongated members angularly arranged around, and secured to the component so as to form chambers extending parallel to the axis of rotation of the cutter, an inlet to each chamber for dust suppression fluid, and outlets from the chambers for directing fluid radially outwardly away from the component.

The members may be plates and the chambers may have a length substantially equal to the axial width of the component. Advantageously, the plates are secured to the inner periphery of the component and the chambers may have a total circumferential area equal to at least a major portion of the area of the inner periphery of the component.

Preferably, the component can be split into two parts along a plane normal to the axis of rotation and each chamber is formed of two sections secured end to end on the two parts, respectively, and interconnected so that dust suppression fluid can flow between the two sections.

Preferably each of the inlets is connected to distribution means positioned adjacent to the hub.

The distribution means may comprise a phasing unit arranged to feed fluid sequentially to only the chambers which momentarily are in a selected segment of the cutter as the cutter rotates.

Preferably, a flexible tube is connected to each outlet to feed fluid to the cutter tool holders. The tubes may be of nylon and may feed fluid to a nozzle located within the tool holder adjacent to a cutter tool. Alternatively, the end of the tube may be adapted to form an outlet for the fluid, the outlet being positioned adjacent to the cutter tool.

By way of example only, one embodiment of a rotary cutter constructed in accordance with the invention will be described with reference to the accompanying drawings in which :

FIG. 1 is a section along the line I--I of FIG. 2 showing a part of the rotary cutter;

FIG. 2 is a section along line II--II of FIG. 1;

FIG. 3 is an incomplete sectional view similar to that shown in FIG. 2 but with an alternative arrangement for feeding dust suppression fluid; and

FIG. 4 is an incomplete sectional view similar to that shown in FIG. 2 but with a further alternative arrangement for feeding dust suppression fluid.

Referring now to FIGS. 1 and 2 which show a part of a rotary cutter of the kind used on shearer type mineral mining machines, the cutter comprises a hub 2 which is adapted to be mounted on a driven shaft (not shown) of the machine. Secured co-axially around the hub 2 is a cylindrical component 4. Two annular discs 6 and 8 and three pairs of radial spokes 10 (only one pair of which is shown) interconnect the component 4 with the hub 2.

Two loading vanes 12 (only parts of which are shown) for cut mineral extend helically around the outer periphery of the component 4 and are arranged to guide cut mineral axially across the width of the rotating cutter towards a conveyor (not shown) on which the machine is mounted. Holders 14 for cutter tools 16 are secured adjacent to the radially outer edges of the vanes 12.

The hub 2 and the component 4 are each split into two parts 18 and 19, 20 and 21, respectively, along a plane extending normal to the common axis of rotation 22. Such splitting of the cutter facilitates transporting the cutter, the parts 18 and 19, and 20 and 21, being bolted together by bolts 24 (see FIG. 2) when the cutter is mounted on the machine.

The cutter also comprises nine elongated members (only three of which are shown ) each formed by four aligned plates 26 which are welded to the inner periphery of the component 4 to provide chambers 28 for dust suppression fluid extending substantially across the whole axial width of the component 4. Each chamber is formed in two sections 28a, 28b extending end to end on the parts 20, 21 of the component 4, respectively. Each pair of sections 28a, 28b are interconnected by a pipe 30 and adaptors 32, 34.

Each of the sections 28a, 28b is further sub-divided by the annular discs 6, 8, respectively, the sub-divisions being interconnected by bores 36 formed in the discs 6 and 8.

Dust suppression fluid is fed into the chambers 28 by a flexible feed pipe 38 which extends from distributor means 40 to adaptors 41 (see FIG. 2). The distributor means 40 is supplied with fluid through the hollow shaft of the machine and may comprise a phasing unit which as the cutter rotates is arranged to feed fluid to only those feed pipes 38 momentarily located within a desired segment of the cutter. Means may be provided so that the segment within which the feed pipes 38 are fed with fluid can be changed. One example of such a distributor means is described in the assignee's prior British Pat. No. 1,110,763.

The chambers 28 have radial outlet bores 42 (see FIG. 1) formed in the component 4 which lead to adaptors 43 secured to the outer periphery of the component 4. Dust suppression fluid is fed from the adaptor 43 to adaptors 44 on the cutter tool holders 14 by nylon tubes 46 which extend along the back face of the loading vanes 12. Shields 48 are welded to the loading vanes 12 to protect the tubes 46 from cut mineral. The fluid is fed along bores 50 in the holders 14 to nozzles 52 located adjacent to the leading face of the cutter tools 16.

In operation, as the machine is traversing along the face cutting coal, dust suppression fluid is fed through the hollow shaft, the distributor means 40 and sequentially to the feed pipes 38 located within the desired segment of the rotating cutter, to the chambers 28 momentarily within the said segment. From the chambers 28 the fluid is fed along the nylon tubes 46 and bores 50 to the nozzles 52 so that a spray of fluid is directed along the leading faces of only the cutter tools 16 which are actually cutting.

This ensures that the dust suppression fluid is used efficiently.

As the plates 26 form chambers 28 which have a total circumferential area almost equal to the area of the inner periphery of the component 4, the radial outlet bores 41 may be located at the most suitable position determined by the ppsition of the tool holder 14 and irrespective of the position of the holder 14 on the lacing pattern of the cutter. Thus the nylon tubes 46 can be kept short and can be positioned adjacent to the loading vane 12 where they are given some protection against cut material flowing in the cutting. Tubes 46a and 46b (see FIG. 2) indicate possible alternative locations of the tube 46. Tube 46b is connected directly in to the outlet bore 42, no adaptor being required.

A circular cover plate 54 (see FIG. 1) is secured to the hub 2 by means not shown to protect the feed pipes 38 and distributor means 40 from cut mineral.

FIG. 3 shows a slightly modified arrangement in which the nylon tubes 46 (only one of which is shown) extend from the outlet bores 42, through the bores 50 in the cutter tool holders 14 to the nozzles 52.

FIG. 4 shows another modified arrangement in which the nylon tube 46 (only one of which is shown) extends from the outlet bore (not shown in FIG. 4) through the bore 50 in the cutter tool holder 14 and provides outlet nozzle means 58 adjacent to the cutter tool 16. The outlet nozzle means 58 is formed by having the end of the tube 46 inclined to the longitudinal axis of the tube 46 and by having a restrictor 60 located in the tube 46 adjacent to the tapered portion. The restrictor 60 is fitted in the tube 46 so that if the inclined portion of the tube becomes damaged the tube can be pulled further along the bore 50 to ensure the end of the tube 46 provides a shroud for the orifice in the restrictor 60. The holder 14 has a projection 59 to protect the end of the nylon tube 46. The restrictor 60 is retained in position by the cutter tool 16, and the tube 46 is retained in position in the bore 50 by a locking adaptor 61. in this case the projection 59 provides the shrouding for the orifice in the restrictor 60.

In a still further modification the projection 59 can be removable from the holder 14.

The cutter tool 16 shown in FIG. 4 is of the kind which necessitates the nylon tube 46 being located on the leading side of the loading vane 12 where it is more likely to be damaged due to the movement of cut mineral. To guard against the possibility of such damage occurring the nylon tube 46 is housed within a metal pipe 62 secured to the loading vane 12.

In modified forms of this arrangement the locking adaptor 61 is replaced by an `O` ring in which case the pipe 62 can extend up to the tool holder 14 and provide maximum protection for the nylon tube 46.

In further modified embodiments of the cutter the plates 26 overlap each other, and the chambers 28 have a total circumferential area equal to the area of the inner periphery of the component 4.

The means for feeding dust suppression fluid is suitable for use with cutter having one or more than two loading vanes. The means can also be used with distributor means which do not include a phasing unit. With such cutters fluid is discharged simultaneously from all the nozzles on the cutter.

In an alternative embodiment of the invention to that shown in FIG. 1 the two chamber sections 28a and 28b are interconnected by means of a bush connector comprising an inner metal tube and an outer rubber sleeve which is bonded to the metal tube and the ends of which are a sliding fit in bores provided in the two adjacent end walls of the chamber sections 28a and 28b, respectively. The metal tube ensures that the bush connector can withstand the pressure of the dust suppression fluid and the rubber sleeve seals the ends of bush connector in the associated bores. In addition the thickness of the rubber is sufficient to allow a small amount of relative angular movement of component parts 20, 21 to take place while still providing a seal for the dust suppression fluid. Such relative angular movement frequently occurs during cutting due to manufacturing and fitting tolerances necessary between the hub 2 and the mining machine shaft and to the cutting forces acting on the cutter head.

Claims

We claim:

1. A rotary cutter for a mineral mining machine, comprising a hub adapted to be drivably mounted on a driven shaft of the machine, a cylindrical component secured co-axially around the hub, cutter tool holders secured around the component, a plurality of elongated members angularly arranged around, and secured to, the component so as to form chambers extending parallel to the axis of rotation of the cutter, the chambers having a length substantially equal to the axial width of the component and having a total circumferential area equal to at least a major portion of the adjacent circumferential area of the component, inlet means to each chamber for dust suppression fluid, and outlet means from the chambers for directing fluid radially outwardly away from the component.

2. A rotary cutter as claimed in claim 1, in which the component can be split into two parts along a plane normal to the axis of rotation of the cutter and each chamber is formed of two sections secured end to end on the two parts, resepctively, and interconnected so that dust suppression fluid can flow between the two sections.

3. A rotary cutter for a mineral mining machine, comprising a hub adapted to be drivably mounted on a driven shaft of the machine, a cylindrical component secured co-axially around the hub, cutter tool holders secured around the component, a plurality of elongated members angularly arranged around, and secured to, the component so as to form chambers extending parallel to the axis of rotation of the cutter, the chambers having a length substantially equal to the axial width of the component and having a total circumferential area equal to at least a major portion of the adjacent circumferential area of the component, inlet means to each chamber for dust suppression fluid, outlet means from the chambers for directing fluid radially outwardly away from the component, and distributing means positioned adjacent to the hub and connected to the inlet means.

4. A rotary cutter as claimed in claim 3, in which the distributing means constitutes a phasing unit arranged for feeding dust suppression fluid sequentially to only those of the chambers which momentarily are in a selected segment of the cutter as the cutter rotates.