Note: Descriptions are shown in the official language in which they were submitted.
ROTARY CUTTING HEAD
This invention relates to a rotary cutting head
particularly, though not exclusively, for the cutting of
minerals such as rock by a so-called roadheader machine for
example.
With such a machine, the cutting head is usually
hollow and is mounted at one end of a boom carried on a
machine chassis, with the boom capable of being displaced to
various positions to cut a roadway or tunnel to the desired
profile. As a means of minimising the airborne dust
generated, conventional practice is to provide a pressurised
water supply to the cutting head for discharge from a
plurality of water spray nozzles located at various points
around the head, usually in the vicinity of picks with which
the head is armed, and also usually in the vicinity of a
terminal collar at one end of the head. In order not only
to maintain water pressure but also to minimize weakening of
the head, the head is provided with relatively fine ~e.g. 5
mm) distribution passageways, but inevitably in the course of
manufacture/repair/refurbishing difficulties are encountered
in ensuring tha~ all~ the drillings are removed from the
passageways, so as to avoid their blockage o the water flow.
~; Currently, such heads are produced in~two or more; ~ , ;
parts, principally from a sold bar or castingj and machined,
.
with the parts then welded together, with an internal water
gallery defined between the welded parts. However, machining
~:
swarf or weld splatter cannot always be detected and/or
:.
.. .: : -, - . ~ . .: : - . :
- 2 ~ r3
flushed out and conse~uently these debris might inadvertently
cause blockage of water passageways. In addition, despite
the use of ~ilters, "clean" water supply cannot always he
guaranteed, particularly in mine conditions, and conse~uently
contamination might be introduced into the head by the water
supply. Furthermore, because of the welded construction, any
blocked head must be returned to the surface for disassembly
and re-welding, if a coal mine is involved.
On examination of used heads, it is discovered that
although, as indicated previously, the water entering the head
is filtered, there is a residue of sludge, possibly formed by
the rusting of the internal parts of the head.
According to the present invention there is providea a
rotary, mineral cutting head, comprising two parts being a
lS base, which has means for attachment to a machine, and a dome,
which is adapted externally to carry pick-receiving boxes,
with a water gallery defined between an external portion of
the base and an internal portion of the dome, and with the two
parts releasably secured together by bolts or studs.
Thus, the head in accordance with the invention by
avoiding welds avoids potential contamination by weld splatter
but furthermore provides the advantagous possibility of
disassembly underground to clear any blockage, resulting in
minimum down time.
Furthermore, it has been proposed to counter the
propensity to rust by plating, e.g. with nickel, internal
surfaces of the head, and with the two-part construction in
accordance with the invention, re-plating can if necessary be
,
.' '
: .
- 3 ~ 3
effected as this may be done after the pick boxes are welded
externally to the dome so that the resultant temperature
increase during box weldlng is not permitted to hava a
deleterious effect on the nickel etc. plating.
Preferably, the dome is provided with a radially
extending planar seating face adapted to abut a corresponding
seating face of the base; and a deformable water sealing ring
may be strategically located between the dome and base.
Securing of the two parts together may be by a plurality of
bolts, e.g. eight, passing through plain holes about a common
pitch circle of the base into correspondingly located, blind
tapped holes in the dome, the bolt axes being parallel to the
axis of rotation of the head. Preferably, the base is
provided with a projecting, generally cylindrical nose which
substantially fills the hollow interior of the dome and has a
central water inlet bore to convey water to an annular
distribution gallery in fluid flow communication with a
plurality of water supply passageways leading to water
distribution nozzles.
The invention will now be described in greater detail,
by way of example with reference to the accompanying drawing,
which is an axial sectional view through a head in accordance
with the invention.
The head 1 comprises a first part, being a base 2, and
a second part, being a hollow interior dome 3. The base 3 is
provided with a stepped abutment surface 4 of a profile to
match that of a complementary support surface of a boom (not
shown), of a road header machine (not shown), to which boom
' '.
- , . .
,. , - :
: ~. ~ . -
,
.
- 4 - ~ r~
the head 1 is attachad by conve~tional means, to be powered
about an axis of rotation 5.
The dome 3 is provided at an inner end with a radially
extending, planar seatiny surface 6 leading, ~ia a chamfer 7
s to a circumferential location surface 8 of an internal
mounting collar 9. At selected locations around an external
surface 10 of the dome 3 are secured, by weld metal 11, a
plurality of pick boxes 12 each housing a replacable pick 13.
Also welded at selected locations to the external surface 10
are a plurality of water spray nozzles 14 in fluid flow
communication with a water supply passageway 15 pro~ided in
the wall structure of the dome and extending to an annular
water distribution gallery 16 deined between internal
surfaces 17 of the dome 3 and external surfaces 18 o~ a
cylindrical nose 19 integral with, and projecting from, the
base 2 and substantially filling the hollow interior of the
dome 3. The nose 19 is also provided with a circumferential
location surface 20 of diameter such that the location surface
8 is a close fit on the surface 20, the latter terminating at
a radially extending, planar seating surface 21 of the base 2,
with a deformable water sealing ring 22 located between the
chamfer 7 and a corner defined at the junction of surfaces 20
and 21, while a central water inlet bore 23 serves to convey
water from a supply source on the boom to the passageways lS
and hence to the nozzles 14.
The dome 3 is secured to the base 2 by a plurality of
studs 24 (typically eight) located about a common pitch circle
and passing throtlgh plain holes 25 in the base 2 and into co-
.,
,
-: :
-~ .. . .
:
~ ' :... ... .
~ 3
-- 5
axial tapped holos 26 in the dome 3, the holes 25 being
countersunk to accommodate bolt heads 27, and the bolt axes 28
being parallel to the axis o rotation 5.
, :
.
. , .
~: . .. - , . . .
.;~: . ~ , : . : , . .
:: ' :' :'
,
