Improvements in Coal Cutting Machines with Special Reference to the Application of Electrical Motive Power.
Year: 1892

page_text: Date of Application, 14th Apr., 1892
Complete Specification Left, 14th Feb., 1893-Accepted, 1st Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in Coal Cutting Machines with Special Reference to
the Application of Electrical Motive Power.
We, ROBERT JOHN CHARLETON and HENRY WALKER of 131 Pilgrim
Street, in the City and County of Newcastle upon Tyne, Electrical Engineers, do
hereby declare the nature of this invention to be as follows:-
Machines constructed according to this invention are specially intended for
working in thin seams of coal and to cut and "undercut" the coal, in such seams,
close down to the "floor,” at, or even beneath, the level of the rails carrying the
machine.
The chief advantages secured are :—
1st. Lightness and portability and special facility for erection in confined spaces.
2nd. Simplicity of driving gear and freedom from noise and jar.
3rd. Self propelling, giving the necessary "feed" advance and counteracting any
tendency of the machine to be displaced laterally from the rails and provided with
adjustable clutch gear to allow of "slip" when necessary.
4th. Special facilities for attaching and detaching the electric motor.
5th. Security from danger by sparking when working in explosive gas, or by
explosion of coal dust.
6th. The facility with which the cutters can be fixed upon the cutter bar, without
weakening the bar, and replaced when necessary.
The machine consists of two side frames, held together by cross stays and having
in them bearings to receive the shaft, to which will be attached, by means of
suitable coupling, the cutter bar. This shaft will be transverse to the machine and
the axis of the electric motor will be longitudinal, a helical gear wheel being fixed
in the motor armature shaft immediately over the corresponding wheel on the cross
shaft and engaging with same. The machine will be supported on 4 wheels, or
rollers, running on rails arranged in portable lengths and fixed to iron sleepers or
by other means to the floor. The traversing or "feed" motion of the machine is
effected by a drum upon a vertical shaft, which being slowly revolved by suitable
gearing from the cutter bar shaft winds upon it a wire rope or chain which is
moored to some fixed point "ahead" of the machine.
"
Or, in a modified arrangement, a rope or chain moored "ahead" and "astern
may be used, having a sufficient humber of turns round the drum to give the
required frictional propelling effect. In order to provide for " slip" in case of
necessity, a driving clutch is fixed upon the drum shaft and adjustably loaded by a
spring, or some equivalent device, by means of which the clutch will slip out of
gear and cease to drive the drum upon which the rope or chain is being wound and
so the forward advance of the machine will be stopped till the resistance, froin
whatever cause arising, is removed or overcome.
In order to obviate the tendency in the machine to be pushed off the rails or
displaced laterally by the backward pressure caused by the cutter bar, the wire
rope or chain is carried from the drum round a guide roller ou the side frame, next

page_text: the cutter bar side of the machine, and then passes round other two rollers
mounted on a bar fixed at one end to the machine framing the action being such as
to give a counteracting leverage to the machine as it travels forward and to resist
the displacing tendency of the cutter bar due to its considerable projection.
:-
As the machine may be required to work in an atmosphere impregnated with
dangerous explosive gases or explosive substances as coal dust the armature and
commutator of the motor will be entirely enclosed in an air tight and gas tight
casing and means will be taken to ventilate same such for instance as follows :-
On the end of the armature shaft at the commutator end will be mounted, so as to
revolve with it, in a suitable closed casing, a small air propeller or ventilator
revolving in such a manner as to discharge the air outwards from the interior of
the casing surrounding the armature. At the opposite end of the casing a
connection will be made to an air pipe through which the air will be drawn by the
action of the air propeller before mentioned, the supply of air being drawn from
some distant point where no danger of explosive gas exists.
The cutter bar will consist of a straight hexagonal, or other shaped, steel bar
having suitable coupling at one end for attachment to the coupling on the machine
shaft and having mounted on it a series of cutters of suitable shape. The cutters
consisting of discs having cutting points, are threaded on the bar, preferably in
tapered series, from the outer end and secured by a binding nut.
Dated this 14th day of April 1892.
T. J. DANSON,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in Coal Cutting Machines with Special Reference to
the Application of Electrical Motive Power.
We, ROBERT JOHN CHARLETON and HENRY WALKER of 131 Pilgrim Street
in the City and County of Newcastle upon Tyne Electrical Engineers do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
Machines constructed according to this invention are specially intended for
working in thin seams of coal and to cut and "undercut "the coal, in such seams,
close down to the "floor," at, or even beneath, the level of the rails carrying the
machine.
The chief advantages secured are:-
1st. Lightness and portability and special facility for erection in confined spaces.
2nd. Simplicity of driving gear and freedom from noise and jar.
3rd. Self propelling, giving the necessary "feed" advance and counteracting any
tendency of the machine to be displaced laterally from the rails and provided with
adjustable clutch gear to allow of "slip" when necessary.
4th. Special facilities for attaching and detaching the electric motor.
5th. Security from danger by sparking when working in explosive gas, or by
explosion of coal dust.
6th. The facility with which the cutters can be fixed upon the cutter bar, without
weakening the bar, and replaced when necessary.
The machine consist of two side frames, held together by cross stays and having
in them bearings to receive the shaft, to which will be attached, by means of
suitable coupling, the cutter bar. This shaft will be transverse to the machine and
the axis of the electric motor will be longitudinal, a helical gear wheel being fixed
in the motor armature shaft immediately over the corresponding wheel on the cross
shaft, and engaging with same. The machine will be supported on 4 wheels, or

page_text: rollers, running on rails arranged in portable lengths and fixed to iron sleepers or
by other means to the floor. The traversing or "feed" motion of the machine is
effected by a drum upon a vertical shaft, which, being slowly revolved by suitable
gearing from the cutter bar shaft, winds upon it a wire rope or chain which is
moored to some fixed point "ahead" of the machine.
Or, in a modified arrangement, a rope or chain moored "ahead" and "astern"
may be used, having a sufficient number of turns round the drum to give the
required frictional propelling effect. In order to provide for “ 'slip" in case of
necessity, a driving clutch is fixed upon the drum shaft and adjustably loaded by
a spring, or some equivalent device, by means of which the clutch will slip out of
gear and cease to drive the drum upon which the rope or chain is being wound and
so the forward advance of the machine will be stopped till the resistance, from
whatever cause arising, is removed or overcome.
In order to obviate the tendency in the machine to be pushed off the rails or
displaced laterally by the backward pressure caused by the cutter bar, the wire
rope or chain is carried from the drum round a guide roller on the side frame, next
the cutter bar side of the machine, and then passes round other two rollers mounted
on a bar fixed at one end to the machine framing the action being such as to give a
counteracting leverage to the machine as it travels forward and to resist the
displacing tendency of the cutter bar due to its considerable projection.
As the machine may be required to work in an atmosphere impregnated with
dangerous explosive gases or explosive substances as coal dust the armature and
commutator of the motor will be entirely enclosed in an airtight and gas tight
casing and means will be taken to ventilate same, such for instance as follows:-On
the end of the armature shaft at the commutator end will be mounted, so as to
revolve with it, in a suitable closed casing, a small air propeller or ventilator
revolving in such a manner as to discharge the air outwards from the interior of
the casing surrounding the armature. At the opposite end of the casing a connec-
tion will be made to an air pipe through which the air will be drawn by the action
of the air propeller before mentioned, the supply of air being drawn from some
distant point where no danger of explosive gas exists.
The cutter bar will consist of a straight hexagonal or other shaped steel bar
having suitable coupling at one end for attachment to the coupling on the machine
shaft and having mounted on it a series of cutters of suitable shape. The cutters
consisting of discs having cutting points, are threaded on the bar, preferably in
tapered series, from the outer end and secured by a binding nut.

page_text: to a drum P on the vertical shaft Q around which it takes a few turns to insure
frictional driving power and thence passes over a guide sheave R to a fixed point
astern. It will be seen that this leading of the rope or chain around the guide
pullies to and from the driving drum counteracts the tendency of the long projecting
cutter bar to force the machine sidewise off the rails.
The shaft carrying the drum P keyed upon it is driven by helical and worm
gearing from the main shaft D and has keyed upon it one half of a friction
Clutch S the other half of which is formed upon the worm wheel T of the driving
gear and the upper end of the shaft Q is fitted with a strong spring U which in
normal working keeps the clutch S in driving gear but when any obstruction to
the cutters is met with in the seam of coal the clutch S overcoming the resistance
of the spring U will slip out of gear and the drum being no longer driven by the
main shaft D will cease to wind upon the rope or chain and the traverse or feed of
ths machine will be arrested so as to avoid straining or breaking the cutters or the
cutter bar.
Referring now to Sheet 2 a form of motor is shewn in which the armature A
(shewn by dotted lines) and commutator B only are enclosed in an air and gas
tight casing C shewn in section excluding all dangerous explosive gases or substances
such as coal dust and to which pure air is introduced through an inlet at D by a
pipe from some part of the mine where no explosive gas is met with, by means of
a small ventilating fan F fixed upon and driven by the armature shaft H and
which expels the air at the outlet O which is preferably fitted with a self acting
non return valve V. The frame F which carries the brushes can be rotated around
the commutator B from outside the casing A by the small hand wheel W having
a worm spindle operating a worm upon the bearing of the frame, and access inay
be had through hand holes in the casing to replace the brushes when required.
The casing A is bolted against the magnets M and yoke piece M which theniselves
enclose the armature and at the other end a thin spun cover C completes the
enclosing casing, the brackets K bolted to the magnets carry a bearing L for the
armature and commutator shaft H the other end being carried in a bearing N
formed in the casing C. The motor is bolted to the frame of the coal cutting
machine by a bracket (P) part of which is shewn on Figure 5.
Although according to the drawing only the commutator and the armature are
enclosed in the casing we may so construct the latter as to enclose the magnets
and the coil but generally the danger of sparking will be perfectly provided against
by the method shown.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that we
do not claim generally enclosing the armature and commutator or other parts of
the motor and ventilating the same but what we claim is :-
1st. In coal cutting machines self propelled on a fixed rope or chain a system of
guide rollers on the machine so disposed relatively to each other that the rope or
chain being carried around them will as the machine travels forward counteract
the tendency of the backward strain on the projecting cutter bar to twist it
laterally upon, or displace it from the rails substantially as described and shewn.
2nd. In coal cutting machines working by electric motive power the particular
arrangement described and shewn whereby the armature and commutator of the
motor or such other parts as may be necessary are enclosed and kept constantly
supplied with pure air by the action of a small air propeller or equivalent ventilator
such as F on the armature shaft so that when working in dangerously explosive
places the risk of explosion by sparking is obviated substantially as described and
shewn.
3rd. A coal cutting machine operated by electrical motive power and self
propelling on a fixed rope or chain consisting of the various parts in combination
constructed and operating substantially as described and illustrated by the accom-
panying drawings or in such modified forms as may be required to adapt the

page_text: machine to work by other motive power than electricity the self propelling, cutter
bar and feed mechanism and the general construction of the machine remaining
practically the same.
T. J. DANSON, F.I.P.A.,
By L. W., per F. B.,
Agent for Applicants.