Improvements in Stamps for Crushing Ores.
Year: 1889

page_text: Date of Application, 29th Jan., 1889
Complete Specification Left, 29th Oct., 1889-Accepted, 18th Jan., 1890
PROVISIONAL SPECIFICATION.
Improvements in Stamps for Crushing Ores.
I, PERCY JOHN OGLE, of 4 Bishopsgate Street Within, London E.C., in the County of
Middlesex, Engineer, do hereby declare the nature of this Invention to be as
follows:-
This invention relates to gravitation stamps, in which the stamp is lifted directly
or indirectly by means of cains, and has for its object the attainment of greater
efficiency in working by enabling the stamps to be driven at a higher speed, and also
if desired to increase the force of the blow.
In practice a gravitation stamp can seldom be driven faster than 80 drops per
minute, by reason of the fact, that if driven faster the impetus imparted to the
stamps by the cam, during the upstroke, would cause it to rise above the path described
by the cam, and thus retard the commencement of the downward stroke to such an
extent, that the cam would have completed its revolution and be in position to raise
the stamp again before it had completed its downward stroke. According to this
invention I provide an elastic buffer or spring which will oppose this tendency of the
stamp to rise above the path of the cam, and which will cause the stamp to fall the
moment it is disengaged from the cam, and at the same time impart a certain velocity
to it, and consequently increase the speed of its downward stroke. This buffer may
consist of one or more metallic springs, or other elastic material, so arranged that
the buffer will be compressed or extended by the tappet, or a collar fixed to the stein
of the stamp during the whole or part of the upstroke.
In its simplest form I employ a metallic spring fixed above the tappet, the stem or
spindle of the stamp passing up through the said spring so that when the stamp is
raised the tappet compresses the spring, and on the completion of the upstroke the
spring by its downward pressure on the tappet accelerates the speed of the stamp and
increases its force. The position of the spring or springs, is preferably unde
adjustable so that the amount of the compression can be regulated.
Dated this 20th day of Janusz 1880
PERCY JNO. OGLE.
COMPLETE SPECIFICATION.
Improvements in Stamps for Crushing Ores.
I, PERCY JOHN OGLE, of 4, Bishopsgate Street Within, in the City of London,
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 :-
This invention relates to ore-stamping mills in which the stamps or pestles are
lifted directly or indirectly by means of cams and allowed to fall by gravitation.
In practice a gravitation stamp can seldom be driven at more than eighty drops per
minute by reason of the fact that, if driven faster, the impetus imparted to the stamp
by the cam during the upstroke, would cause it to rise above the path of the cam and
thus retard the commencement of the downward stroke to such an extent that the
cam would have completed its revolution and be in position to raise the stamp again
before the latter had completed its downward stroke.
The object of my invention is to obtain greater efficiency in working, than hereto-
fore, by enabling the stamps to be driven at a higher speed and also, if desired, with
an increase in the force of the blows.
In carrying out my invention I provide an elastic buffer or spring which will
oppose the tendency of the stamp to rise above the path of the cani, and which will

page_text: cause the stamp to fall the moment it is disengaged from the cam, and, at the same
time, impart a certain velocity to it and consequently increase the speed of its down-
ward stroke. This buffer may consist of one or more metallic springs or of other elastic
material, so arranged that it will be compressed or extended by a tappet, or a collar
fixed to the stem of the stamp or by the stem itself during the whole or part of the
upstroke.
To enable my invention to he fully understood, I will describe how it may be carried
into practice by reference to the accompanying drawings, in which
Figure 1 is a front elevation, partly in section, of a two stamp ore crushing mill
provided with my improvements; and
Figure 2 is a central vertical section of the same.
Similar reference letters indicate similar parts in both the figures.
a is the frame of the mill having the cross pieces b, b₁, and c, c are the pestles or
stamps which slide in guides in the cross pieces b, b¹ and are driven from the shaft d
by the cams e, e acting on the tappets f, f. All the said parts however being of
ordinary construction require no further description.
9,9 are the buffers arranged according to my invention, the said buffers, as shewn
in the drawings, being helical springs arranged around the stems of the stamps.
Each of these springs is arranged between, and at its ends attached to, two plates h, h²,
the upper of which is secured to the cross piece band has connected with it pins i, i
serving as guides upon which the lower plate slides. The springs by being thus
confined are prevented from becoming displaced by the rotary motion imparted to the
tappets by the cams.
By this arrangement of buffers it will be obvious that, when the stamps are raised
by the cams e, e, the tappets ff will impinge against the undersides of the plates h¹, h¹
and compress the springs g, g as shown at the right hand of Figure 1, which will thus
act upon the stamps to prevent their rising above their normal height. On the
completion of each upstroke and after the cams have moved out of engagement with
the fappots ff the springs by their downward pressure accelerate the speed of the
stamps and thereby increase the force of the blows which they deliver.
In some
cases the buffers are so placed that they will only be compressed by the tappets when
the latter rise above their normal path.
The position of the springs may be made adjustable, if required, by varying the
normal position of the plates h³, by means of screw nuts on the guide pins i, i or by
other desirable means.
Although I have shown metallic springs it will be obvious that springs of other
elastic material can be used and that instead of compressing the said springs by
the upward movement of the stamp springs may be arranged so as to be extended
when the stamps are raised.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
(1.) In an ore-crushing mill the employment of buffers for preventing the stamps
from rising above their normal height, whereby such stamps can be driven at a higher
speed than heretofore, substantially as set forth.
(2.) The application to an ore-crushing mill of buffers arranged substantially in
the manner hereinbefore described and illustrated in the accompanying drawings, for
the purpose specified.
(3.) The manufacture and use of stamp mills having elastic buffers arranged sub-
stantially as hereinbefore described for the purpose specified.
Dated the 29th day of October 1889.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.