Mining tool with automatic sprinkler control

A mining tool with a rotary body carrying a number of peripherally spaced cutters has a water channel terminating in the vicinity of each cutter at a spray nozzle for the irrigation of particles such as coal dust detached from the mine face. The water supply for each nozzle is controlled by the associated cutter so as to be unblocked only when its working edge encounters resistance sufficient for a limited swing of the cutter shank about a pivotal axis against the force of a biasing spring, thereby opening a valve normally held closed by that spring.

FIELD OF THE INVENTION 
My present invention relates to a mining tool of the type having a rotary 
body which carries a number of peripherally spaced cutters or picks that 
are each provided with a working edge facing in the direction of rotation. 
BACKGROUND OF THE INVENTION 
Such a tool may be used to work at a mine face on a seam of anthracite 
coal, for example, whose fragmentation by the rotating cutters gives rise 
to considerable dust development. Continuous sprinkling of the detritus 
with water enables the dust to be precipitated and to be carried off for 
further processing. For economic reasons, and to simplify the recovery by 
avoiding the need for a separate drying step, it is desirable to hold the 
water supply within moderate limits, e.g. at or below 6% by weight of the 
extracted coal. Thus, rotary heads carrying axially projecting picks have 
been provided in the past with valves which block the flow as long as the 
picks are not in contact with a mine face. The valve responds to axial 
pressure and thus unblocks the flow intermittently as the tool is 
progressively advanced into the seam. 
When the cutters project generally radially from the periphery of the 
rotary body, e.g. with shearer-type mining tools or augers as described 
for example in U.S. Pat. Nos. 3,747,982 and 4,219,239, such a control 
cannot be used since the cutters are not axially shiftable. Moreover, each 
individual cutter comes into working contact with the mine face only 
during part of a revolution. The cutters, therefore, need not be supplied 
with water during their nonworking phases. For this purpose it is known, 
e.g. as noted in the aforementioned U.S. Pat. No. 3,747,982, to control 
the water supply by means of a distributor cutting off the flow to a 
segment remote from the mine face, yet this will not prevent the unneeded 
emission of water from an opposite segment when the cutters thereof are 
not in contact with the mine face. 
OBJECT OF THE INVENTION 
Thus, the object of my present invention is to provide a mining tool of the 
type referred to with means for effectively controlling the supply of 
water in accordance with the activity of each cutter. 
SUMMARY OF THE INVENTION 
I realise this object, in accordance with my present invention, by mounting 
the shank of each cutter on its supporting body with freedom of limited 
pivotal motion in a plane perpendicular to the axis of rotation and 
providing biasing means acting upon the shank to urge the working edge of 
the cutter forward in the direction of rotation. A conduit connected to a 
supply of water under pressure includes a channel which terminates at an 
outlet in the vicinity of each cutter, the outlet being provided with one 
or more nozzles sprinkling water onto a mine face being worked at and onto 
the mineralic matter detached from that face, referred to hereinafter for 
convenience as coal. A valve interposed between the channel and its outlet 
significantly reduces or completely blocks the flow of water to the nozzle 
or nozzles in a normal position but is displaceable by the shank of the 
associated cutter into an unblocking position upon repression of the 
working edge of the cutter against the force of the biasing means by 
contact with the mine face. 
According to the embodiment more particularly described hereinafter, the 
shank of each cutter is pivotally mounted in a holder having a bore 
generally perpendicular to that shank which communicates with the 
associated channel and its outlet. The valve controlled by the cutter 
comprises a piston which is movable in the bore and is urged into contact 
with the cutter shank by a spring constituting the biasing means. The 
piston has a passage, preferably a peripheral groove, which opens onto the 
outlet only in the unblocking position but advantageously has an extension 
through which water under pressure can reach the back of the piston in 
order to supplement the retaining action of the biasing spring in the 
normal position.

SPECIFIC DESCRIPTION 
The drawing illustrates part of a rotary body 2 which could be a drum of 
the type shown in U.S. Pat. No. 4,049,318, for example. Body 2 carries a 
number of generally radially projecting holders 3, 3' etc. (only two 
shown) accommodating respective cutters or picks 1, 1' etc. Though these 
holders are shown positioned directly on the periphery of body 2, they 
could also be mounted on one or more helical loading vanes when that body 
is designed as an auger shaft of the type described in the two U.S. 
patents mentioned earlier. 
Cutter or pick 1, which of course is representative of all other cutters of 
the mining tool, has a shank 4 which in contrast to conventional 
arrangements is not fixedly mounted in its holder but is limitedly 
pivotable about a pin 23 in a plane perpendicular to the axis of body 2. 
Shank 4 has a flattened side 24 which is in permanent contact with tip 11 
of a piston 10 slidable in a cylinder bore 12 of a block 7 adjoining the 
holder 3; piston extremity 11 is received in a transverse bore 28, formed 
in the wall of holder 3, and carries a packing ring 13 designed to prevent 
the escape of water under pressure which enters the cylinder 12 from a 
central conduit 27 in body 2 through a branch channel 26 and an aperture 6 
in the inner wall of block 7. Similar branch channels 26', 26" are seen to 
extend from central conduit 27 within body 2 to corresponding blocks 
mounted adjacent holder 3' and other holders not shown. 
Piston 10 is provided with further packing rings 14 flanking an annular 
groove 18 which permanently communicates with channel 26 via aperture 6 
and, in the illustrated unblocking position, opens onto an outlet 8 into 
which a spray nozzle 5 is inserted with the aid of threads 9. Piston 10 is 
biased toward the left, into contact with shank 4, by a compression spring 
17 partly received in a cavity 22 of a cap nut 15 engaging internal 
threads 16 of the right-hand end of bore 12, the nut resting against a 
shoulder 20 of that bore. An axial bore 19 in piston 10 communicates 
through a radial extension thereof with groove 18 and opens at its 
opposite end into the part of cylinder 12 containing the spring 17. 
In operation, body 2 is assumed to rotate clockwise about its axis whereby 
a working edge 25 of pick 1 cuts into an adjoining mine face during part 
of a revolution. Fragments of rock and coal broken from that mine face are 
irrigated by water emitted from nozzle 5 to suppress dust formation; this 
is possible because the reaction of the mineral matter attacked by the 
pick represses same against the force of spring 17 to swing it from a 
normal position into the illustrated unblocking position in which its 
flank 24 rests against the wall of holder 3 while the groove 18 of piston 
10 communicates with outlet 8 to let the water from channel 26 reach the 
nozzle. When the pick 1 leaves the mine face, spring 17 advances the 
piston 10 to the left so that pick 1 swings into its normal or inactive 
position as groove 18 cuts off the outlet 8 while remaining in 
communication with aperture 6; this lets water under pressure flow through 
bore 19 into the right-hand part of cylinder 12 to reinforce the biasing 
action of spring 17 tending to hold the pick in its normal position. The 
beginning unblocking of outlet 8 upon initial contact with the mine face 
creates a toggle effect accelerating the restarting of the water jet. The 
biasing force can be reduced, if necessary, by partly unscrewing the nut 
15, e.g. with interposition of one or more washers between that nut and 
shoulder 20. 
In order to facilitate disassembly for purposes of inspection or repair, 
the right-hand end of bore 19 is advantageously provided with female 
threads 21 enabling the engagement of piston 10 by a complementarily 
threaded implement by which the piston can be extracted. 
As will be apparent from the foregoing description, the pivotal mounting of 
pick 1 in its holder 3 and the associated valve assembly in block 7 
ensures that water from supply conduit 27 is emitted by the associated 
nozzle 5 only when that pick is actually cutting into a mine face. The 
disclosed assembly can be readily installed on existing mining augers or 
cutter-carrying drums; it should also be noted that the valve assembly 
10-22 is well protected by block 7 against damage by mineral fragments 
striking the peripheral surface of the tool. 
When the piston 10 is nonrotatably held in its cylinder bore 12, the 
peripheral groove 18 could be replaced by a throughgoing diametrical 
passage opening directly into axial bore 19. 
If desired, the outlet 8 could be slightly enlarged or shifted to the left 
so that the outflow of spray water is throttled but not completely stopped 
in the normal position of pick 1. In any event, the significant reduction 
or blocking of the water supply to the nonworking picks enable the flow to 
the active picks to be intensified for effectively cooling same while 
precipitating the evolving dust. This will help prevent sparking and thus 
will minimize the risk of underground explosion.