Certain Improvements in Rock Breakers.
Year: 1890

page_text: Date of Application, 14th Jan., 1890-Accepted, 15th Feb., 1890
COMPLETE SPECIFICATION.
Certain Improvements in Rock Breakers.
I, MILES BENJAMIN DODGE, residing at No. 8 Hill Street, in the city and county
of San Francisco, and State of California, one of the United States of America,
Mining Engineer, 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 :-
My invention relates to certain improvements in rock-breakers.
It consists of a box, within which the eccentric for operating the crusher-jaws
works, and by which box irregularity from wear will be taken up.
It also consists in the employment of springs, whereby the projecting lever-arm
of the movable jaw is kept in contact with the pitman of the operating eccentric ;
and further, in the employment of springs, whereby the lower part of the movable
jaw is drawn back from the face of the fixed jaw, together with certain details
of construction and adjustment, all of which will be more fully explained by
reference to the accompanying drawings, in which
Figure 1 is a vertical sectional view taken through the crushing-jaws, and actuating-
mechanism thereof, showing the manner of conveying the power from the eccentric to
the crushing-jaws through supplemental thrust-plates.
Figure 2 is a vertical section, showing a form of apparatus in which the power is
applied directly to a lever formed as an extension of one of the crushing-jaws.
Figure 3 is a perspective exterior view of a crusher, similar to that shown in
Figure 2, and showing the application of the exterior springs.
Figure 4 is a perspective view of a section of the movable jaws showing the
fulcrum-shafts of the movable-jaw and part of the box and collar with the tension
rod.
This invention is applicable to that class of rock-breakers in which one or more
reciprocating-jaws are caused to move to and from each other while the rock is passed
between them; this action of the jaw being effected by means of an eccentric upon
a driven shaft, and the eccentric is connected with the moving jaw of the rock-
breaker by connecting rods or arms in any suitable or well-known manner.
As all the wear and strain of the work is brought upon the eccentric at one
point of its circumference, while it is forcing the jaw forward against the material
which is passing between the two jaws, this eccentric soon becomes worn at the
point of greatest pressure so as to be untrue, and if the box is left loose it will
pound and greatly add to the wear and noise.
If, under these circumstances, any attempt should be made to take up the wear
upon one side by a rigid adjustment, it would make the fit too tight upon the other,
so that the box would be broken on account of the irregular shape of the eccentric.
The first portion of my invention consists in the application of springs to the
box so that it may open and close and accommodate itself to irregularities in the
shape of the eccentric.
In Figures 1, and 2, A is the main shaft, having a pulley B, to which power is
applied to rotate it, and a balance-wheel C, as shown.
D is the eccentric formed or secured upon the shaft and having a sufficient throw
to move the jaw of the rock-breaker as much as may be desired.
The shaft turns in suitable journal-boxes at each end, these boxes being supported
upon a frame, and the eccentric has a box enclosing it, situated between the two
stationary boxes, above referred to, and a connecting rod or pitman E, extends
from this box so that the rotation of the eccentric produces a reciprocating motion
of this pitman.

page_text: As shown in Figure 2, motion is imparted from this pitman directly to the rear
extension of the rock-breaker jaw, and, as shown in Figure 1, intermediate rods F
are employed, forming a knee-lever, between the adjacent ends of which the
reciprocating pitman E works, so that while the end of one of these rods F, abuts
against a stationary plate in the frame, the other one abuts against the crushing-jaw,
and thus moves it to and fro.
The box enclosing the eccentric consists of two parts G, and H, these parts being
held together by bolts I, with adjusting nuts J.
In order to allow the cap of the box to accommodate itself to such irregularities as
may occur in the form of the eccentric by reason of the unequal wear upon its surface,
I employ spiral, rubber, or other elastic springs K, which are so applied as to press
upon one part of the box.
It will be manifest that these springs may be arranged in various ways, which will
suggest themselves to the mechanic.
In Figure 1, bolts are shown as passing through the flanges of the upper part of
the box, and the ends of the horizontal bar L beneath.
Upon the central portion of this bar the adjusting cap H, is supported, and it will
be manifest that this cap will be allowed to move away whenever an irregularity or
enlarged portion of the eccentric passes over it, the elasticity of the springs allowing
of this movement, and whenever a smaller portion of the irregularly-shaped eccentric
passes over this cap, the tension of the springs will keep the cap in contact with the
surface; and in this manner will allow a free movement of the parts and will, at the
same time, prevent any looseness or pounding which would occur between the two
parts of a box which are rigidly maintained with reference to each other.
In Figure 2, the bolts are shown as passing through the flanges of the box and the
corresponding flanges of the cap, the springs resting upon the tops of the flanges,
and any desired tension being produced by screwing down the nuts upon the ends of
the bolts so as to press with greater or less force upon the springs.
It will be manifest that these elastic buffers may be of any material which will give
sufficient elasticity for the purpose. They serve to hold the cap closely against the
eccentric so that as it rotates within the box, the box will by reason of its motion
accommodate itself to any irregularities in shape.
The second portion of my invention is illustrated in Figures 3, and 4.
The side frames of the machine are represented by a, a, and the stationary
jaw b, is fixed at one end of these frames in a manner similar to that shown in
Figure 2.
c is the movable jaw having the lower end supported upon fulcrum-shafts d, which
vibrate in journal-boxes supported upon side frames a of the machine. From the
rear of the jaw c, a triangularly-shaped lever or extension e, projects, extending
backwardly between the side frames a, as shown plainly in Figure 3; and in its outer
end, farthest from the crushing-faces of the jaws, is a semi-cylindrical groove or
channel, which fits upon the corresponding upper end of the connecting rod or
pitman E, through which power is applied from the eccentric upon the shaft A, so as
to cause the lever-arm e, and the jaw c, to oscillate about its fulcrum-shaft d.
The lower edge of the crushing-face of the jaw c, is sufficiently above the fulcrum-
shaft d, to form with the face of b, a narrow discharge-throat, and the least movement
of the jaws to and from each other, takes place at this point, the upper and widest
portion of the jaws having the greatest movement.
When the machine is being run at a high rate of speed, it is difficult to
maintain a close contact between the end of the lever-arm e, and the connecting
pitman E, and in order to maintain this contact and prevent a separation and
pounding at this point, I have shown the shafts or trunnions h, projecting from the
sides of the connecting pitman E, and having sleeves or collars i, which fit loosely
'upon these trunnions.
These sleeves i, have upwardly-projecting extensions j, into which the bolts or rods
are secured, as shown.

page_text: These bolts pass upward from the extension j, through the lugs l, at the end of the
lever-arm e, and are surrounded by springs m, which rest upon the upper sides of the
lugs 1.
Above these springs m, are the washers n, and the nuts o may be screwed down upon
them, so as to compress the springs m, to any desired degree of tension.
By this means it will be manifest that the end of the lever e, and the upper end of
the pitman E, will be held firmly in contact with an elastic pressure, which may be
regulated at will by the tension of the springs m.
The boxes in which the fulcrum-shafts d vibrate, soon become worn and loose under
the heavy pressure required to crush the material between the jaws, and when the
discharge-throat is full of rock, the rock itself will act as a fulcrum, and the lower
part and the fulcrum-shafts will then acquire a to and fro motion in the boxes, which
greatly interferes with the efficiency of the crusher. In order to remedy this, I secure
collars P upon the projecting ends of the fulcrum-shafts d, by means of set-screws p,
or by other convenient means.
Upon these collars are stout eyes Q, standing in an approximately-horizontal line,
with the center of the fulcrum-shafts d. The hook-bolts R, are attached to these eyes
and extend horizontally along the sides of the frame a, passing through projecting
buttresses U, cast upon the sides of the frame a.
Strong elastic buffers or springs T, surround the projecting ends of the bolts R, and
washers S are forced against the springs by means of nuts s'. By these means the
fulcrum-shafts d, are strongly held against the rear sides of the bearing-boxes, and the
fulcrum is thus maintained at this point. This insures a slight to and fro movement
of the jaw at the throat, which, as before described, is above the plane of the fulcrum-
shafts, and it increases from this point to the top of the jaw, where the motion becomes
the greatest.
The journal-boxes V, of the fulcrum-shaft d, are fitted to slide in guiding slots in
the bottom of the frame a, and plates or washers W, are shown placed in the slots in
front of the boxes.
The whole being locked firmly by set-screws X.
The opening of the throat of the machine is regulated by means of these plates; one
or more of the plates may be removed from the fronts of the boxes and placed in the
rear, the set-screws being again tightened to hold them securely in place.
It will be seen that by screwing the nuts s¹, farther upon the bolts R, the tension
upon the springs T, will be increased to any required degree.
The jaws of the breaker are, preferably, made with removable dies which form the
faces of the jaws, and are held in place by bolts passing through them and the
jaws in any suitable manner.
These dies are, preferably, formed of alternate hard and soft surfaces by boring
holes into the faces of the dies and inserting hard steel plugs into them. These
plugs always projecting slightly above the surrounding surface of the die, so that
the irregularity of the surface, thus maintained, will serve to crush in a better manner
than the perfectly plain and smooth surface which wears equally in all parts.
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 two-part box enclosing the eccentric from which motion is transmitted to
the movable jaw of a rock-breaker, and the elastic springs or buffers by which the
parts of the box are held in contact with the eccentric, whereby the box is allowed
to automatically adjust itself to the irregularities in the shape of the eccentric,
substantially as described.
2. The fulcrum-shaft, about which the movable jaw oscillates, sleeves or collars
fixed upon the ends of the fulcrum-shaft, rods connected with said sleeves or collars
by hook and eye bolt or other mechanism, and having their opposite ends passing
through stationary lugs or buttresses with springs and nuts, whereby an adjustable

page_text: elastic pressure is brought upon the fulcrum-shafts to hold them in contact with the
rear portion of the boxes in which they turn, substantially as described.
3. In combination with the fulcrum-shafts of the oscillating jaw, the boxes in which
they turn fitted into open slots in the frame of the machine, and plates or shims placed
before or behind said boxes in the openings so as to regulate the amount of throat-
opening between the crushing-jaws, substantially as described.
4. The combination with the rearwardly-extending lever-arm by which the oscil-
lating jaw is moved, the eccentric and pitman through which motion is communicated
to said lever-arm, of the projecting trunnions extending outwardly from the thrust-
plate or pitman, sleeves loosely surrounding said trunnions, rods extending upwardly
from said sleeves through the sides of the oscillating lever, and springs with adjusting
nuts and washers, whereby their tension may be regulated, said springs acting to
hold the end of the lever and the thrust-plate or pitman in contact, substantially as
described.