Method of and Apparatus for Breaking Rock.
Year: 1898

page_text: Date of Application, 12th Apr., 1898-Accepted, 20th May, 1898
COMPLETE SPECIFICATION.
Method of and Apparatus for Breaking Rock.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from Thomas Alva Edison, of Llewellyn Park, in the
County of Essex and State of New Jersey, in the United States of America,
Inventor), and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The object of the invention is to produce a simple and effective method and
apparatus for the breaking of rock.
I employ a pair of rolls of massive size and weight, having suitably roughened
or irregular surfaces. To these rolls is applied a small power, sufficient to bring
the rolls up to a high speed when unloaded. The rolls are mounted side by side
in a suitable frame, and have a wide gap between their opposing surfaces. They
are rotated in opposite directions, the movement of the irregular surfaces being
downward through the gap. When the rolls have acquired their full speed, a
large piece of rock or several pieces will be elevated over the rolls, and being
guided by a hopper, will fall upon the rolls over the gap between them. The effect
is to almost instantaneously partially arrest the motion of the rolls, which retarda-
tion will take place in a fraction of a second, whereby will be developed or ex-
pended an enormous kinetic energy, which cracks the rock and breaks it into
sizes small enough to pass through the gap. To permit this reduction in speed
the power may be applied through friction clutches; or instead there may be used
a suitable device for disconnecting the rolls immediately before the rock is dumped
and reconnecting them immediately after the rock is broken, or even by allowing
the speed of the engine to be reduced with that of the rolls. While, another load
of the rock is being elevated, the rolls will be again brought up to their full
speed.
The rolls are faced with removable wearing plates, which are provided with
knobs, which engage the rock. There are also provided on one roll, one or more
lines of larger knobs, which give to the rock sledging blows, to reduce it to a size
to be broken by the smaller knobs. This double operation of sledging by the
larger knobs and then breaking by a rolling action of the smaller knobs makes
the rolls effective for the breaking of pieces of rock of a diameter even as large as
the distance between the centres of the rolls.
In the drawings:
Fig. 1 is a side elevation and partial section of the apparatus ;
Fig. 2 is a plan, partly in section, of the rolls;
Fig. 3 is a side elevation of the rolls ;
Figures 4 and 5 are views of the thrust bearing;
Figures 6 and 7 are a side elevation and a plan of a portion of one of the
friction bands; and
'
Fig. 8 is an enlarged view, showing the manner of applying the removable plates
to the rolls.
A and B are the two rolls, provided with wearing plates a, secured by bolts b,

page_text: (Figures 8 and 9) which pass through locking bars b¹, provided with shoulders b²,
abutting against shoulders on the wearing plates a, whereby each of said locking
bars serves to hold in place the adjoining edges of two of said plates. The wearing
plates have projecting knobs c of uniform height, and preferably at opposite
points on one roll is a line of larger knobs d for giving the sledging blows. These
sledging knobs are provided with inclined surfaces d', which strike the rock. By
employing the bars b¹, I prevent the impact of the rock from dislodging the
plates, since all of the bolts b around the entire circumference receive such impact.
C is the frame. On each shaft is a thrust bearing D, composed of split steel
rings e carried by grooves in the shaft, the shaft being surrounded by a two part
collar E, E¹ having grooves for receiving 'said rings. The parts E, E¹ are bolted
together by bolts e', and to the journal box by bolts e². A dust cap is secured to
the collar. Fis a loose 'pulley, on the other end of each shaft, and outside of this
pulley is a band wheel G secured to the roll shaft by bolts f¹. Around each band
wheel is a steel band H, carrying iron friction plates g. The band H may be
divided and the two parts secured together by an adjusting bolt h. Carried by
each pulley F is a bell 'crank i, see Fig. 3, the arins of which are secured to the ends
of the friction band H. The extreme end of the bell crank i is connected to the
rod j, passing through a plate k and carrying a coiled spring 'l and adjusting nut m.
The driving belt I passes over an idler J, thence over one pulley and in an opposite
direction over the other pulley. The belt I drives the rolls in opposite directions,
through the friction bands H, but when a mass of rock is dropped upon the rolls,
the friction bands slip upou the band wheels G, and after the rock has passed
through the rolls the friction bands continue to slip until the rolls are again brought.
up to speed.
In Fig. 1, the hopper K extends from the platform L, above which is an electric
crane M. The space between the platform Land the crane M is open at the front
of the building. The rock is loaded on open buckets N, which are brought on cars
to the front of the building. The crane is run out over the cars, the hoisting chain
P is lowered and its three hooks n are attached to the loaded bucket. The bucket
is then elevated and moved over the hopper K (Fig. 1, dotted lines).
The bucket is then moved to one side of the hopper and lowered until it rests.on
the wooden bars o on the platform. The two forward hoisting hooks n are then
detached, and the crane then pulls up on the hoisting chain P, which tilts the
bucket (see Fig. 1, full lines) and dumps the rock into the hopper K, the front edge
of the bucket engaging with one of the bars o so as not to move laterally. After
the load is dumped, the bucket is again lowered, the forward hooks are attached,
the bucket raised, and the crane moved so as to place the empty bucket again
on the car, when the hoisting chain is' attached to a loaded bucket and the operation
referred to is repeated.
Having now particularly described and ascertained 'the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I claim
*is:
1. The method of breaking rock, consisting in driving a pair of massive rolls at a
high speed, in periodically delivering charges of rock to said rolls so asito
partially arrest the motion thereof, thereby breaking the rock by kinetic energy,
and in restoring the speed of the rolls between the intervals of feeding the material
thereto, substantially as set forth.
2. The method of breaking rock, consisting in driving a'pair of massive rolls at a
high speed by means of a small power capable of running the rolls up to speed
when no work is being done, the power being connected to said rolls by a slipping
connection, whereby the speed of the rolls may be reduced without correspondingly
reducing the speed of the driving engine, in periodically delivering charges' of rock
to 'said rolls-so as to partially arrest the motion-thereof, thereby breaking the 'rock
by kinetic energy, and in restoring the speed of the rolls during the intervals or
sbetween the intervals of feeding, substantially as set forth.

page_text: 3. An apparatus for breaking rock by kinetic energy, consisting of two massive
rolls having roughened or irregular surfaces for catching the rock and subjecting
it to a rolling action, an engine for driving said rolls in opposite directions and
slipping connections between said engine and the rolls, whereby the speed of said
rolls may be reduced in breaking the rock without effecting a corresponding reduc-
tion in the speed of the engine, substantially as set forth.
4. An apparatus for breaking rock by kinetic energy, consisting of two
massive rolls having roughened or irregular surfaces for catching the rock and sub-
jecting it to a rolling action and provided with projections of greater extent for
sledging large pieces of rock and reducing them to a size small enough to be sub-
jected to the rolling action, an engine for driving said rolls in opposite directions,
and slipping connections between said engine and the rolls, whereby the speed of
said rolls may be reduced in breaking the rock without effecting a corresponding
reduction in the speed of the engine, substantially as set forth.
Dated April 12th 1898
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.