Improvements in or relating to High Speed Steam Stamps for Crushing Ores.
Year: 1898

page_text: Date of Application, 22nd Mar., 1898-Accepted, 23rd Apr., 1898
COMPLETE SPECIFICATION.
Improvements in or relating to High Speed Steam Stamps for
Crushing Ores.
We, FREDERICK ALEXANDER PARNELL, of 10, New Broad Street, in the City of
London, and CHARLES SPENCER MADAN, of 10, Belfield Road, Didsbury;
Manchester, in the County of Lancashire, Mechanical 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:
Our invention relates to direct-acting high-speed steam stamps for crushing gold
and other ores of the kind referred to in the Letters Patent No. 7300 of A.D. 1897
granted to F. A. Parnell. In the stamp therein described a partial to and fro
rotary action is imparted to the stamp at each upward and downward stroke, by
means of a rifled bar attached to the cylinder cover and working through a rifled
nut fixed in a hollow in the reciprocating piston. According to this arrangement
the stamp head although it is rotating at the moment of striking the ore, yet always
strikes the ore in the same position.
According to our present improvement we provide a continuous step-by-step
rotation of the stamp head always in the same direction so as to equalize the wear
on the stamp head, in combination with the rotation at the moment of striking the
ore which is attained by the former invention.
The special means we employ for causing and ensuring a certain and positive
step-by-step rotary action always in the same direction and in any required degree.
of the stamp head, on its downward stroke, not only ensure equal wear of the
working face of the stamp head owing to its never coming twice in succession in
the same position on the ore, but also facilitate the percussive grinding action
which is included in the former invention. In stamps of the Parnell type a light
framework preferably of steel and substantially of the form illustrated herein is
used, and on the base of this are mounted the "California" stamp boxes and
also the necessary uprights and cross beam for carrying the stamp actuating
mechanism. A direct-acting high speed steam stamp usually consists of a number
of adjacently arranged similar steam cylinders placed vertically one above each
stamp head, each cylinder being provided with a piston and piston-valve, and each
piston rod attached to its stamp spindle by a taper coupling-clip adapted to be
disconnected when required. By one method of applying our improvement to such
stamps each cylinder is provided with an internal rifled bar not fixed but capable
of rotation and working through a rifled nut fixed in the piston-recess; such rotary
rifled bar is provided with ratchet gear by means of which the required intermittent
step-by-step rotary motion always in the same direction is imparted to the piston
and to the stamp head at each downward stroke. By an alternative method we
dispense entirely with any means located within the cylinder for intermittently
rotating the stamp and employ external and hence more readily accessible means
for effecting the same result. Such means consist of a rifled or spirally
grooved part or sleeve formed on or applied to each stamp stem and a ratchet
wheel having an elongated boss internally rifled throughout its entire length
CD 077

page_text: through which the said rifled part of the stem works. The internally rifled ratchet
wheel is suitably mounted in the frame and its step-by-step rotation is maintained
in the same direction by a pair of adjacently disposed spring-pressed pawls acting
upon it in the same way as above indicated.
We will now fully describe our improvements in reference to the accompanying
drawings in which Fig. 1 is a longitudinal section through one cylinder and piston
of a stamp, showing internal means for intermittently rotating the piston and
stamp. Figs. 2 and 3 are sections respectively on lines 1-2 and 3-4 of Fig. 1.
As in the Parnell arrangement above referred to, in the upper end of the piston P
is a tapped recess into which is screwed the rifled nut N, through which works the
rifled bar R. This is not fixed as in the former arrangement but is mounted in
such manner as to be free to be rotated; for this purpose the rifled bar is provided
with a collar which is supported by the ring. B resting on an elastic bearing band
to its upper part is fixed a ratchet wheel M Figs. 1 and 3, secured by a nut N
fitting within a recess in the cylinder cover C. L Lare races for lubricant provided
with stop studs and ww are rubber rings or coiled spring cushions for minimising
shocks. The ratchet wheel and rifled bar are prevented from rotating in one
direction, that is to say, during the downward strokes of the piston by stop
pawls p p always pressed into engagement with its ratchet teeth by springs 88
Fig. 3, and thus on each downward stroke of the piston the rifled bar R being held
firmly by the pawls p and prevented from rotating the piston itself must be rotated
and with it the stamp head: the rifled bar, however, is free to be rotated idly
during each upward stroke of the piston which therefore is not rotated.
Referring now to our improved externally arranged means for obtaining the
same result, Fig. 4 is a side elevation partly in section and Fig. 5 a front elevation
of a direct-acting high-speed percussive and rotary steam stamp battery of the
"California" type. Fig. 6 is a plan of the ratchet-wheel with rifled boss and
controlling pawls, and Fig. 7 an enlarged view showing the rifled part of the stem
and other detail.
Upon the stem S of each stamp we make a rifled part R of rather greater length
than the full stroke of the stamp. This rifled part may either be cut or twisted
in the stem itself; or a separate rifled sleeve of tough or "tool" steel may be
slipped over or otherwise applied to and fixed upon an ordinary stem in the proper
position; in the cross beam D or in a suitable bracket or fitting bolted thereto is
placed a ratchet wheel M made of steel, gunmetal, phosphor-bronze or other hard a
metal and having a long boss m internally rifled throughout its entire length with
rifling corresponding to that of the stem which works through it; the ratchet wheel
is controlled by two pawls pp forced into engagement with its teeth by springs 8 8
such as above described. It is advantageous to encase the ratchet gear in a dust-
tight box as shown at T which may be fitted in any convenient way to the cross 4
bar D. A specially long bearing H with stuffing box h and preferably metallic
packing is fitted for preventing any oil entering the stamp box A, since, as is well
known, the effect of oil in the ore is injurious to the subsequent process of
amalgamation with copper plates. By this arrangement as before at each upstroke
of the piston the ratchet wheel M is idly rotated, but on each downstroke the 4
ratchet wheel is held firmly by the pawls p p and cannot be rotated as the rifled
part R passes through it and hence the stem and stamp must be rotated.
obtain an intermittent rotation of the stamp by which wear of the head is greatly
reduced and more efficient work results.
Thus we
We prefer to impart to the stamps a partial rotation of at each down-stroke so 5
as to obtain eight blows to one complete revolution of the stamp.
"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 what
we claim is:
1. In a direct-acting high-speed steam stamp of the kind above referred to, 5
the use in combination with a rilled nut fixed in a recess in the piston of a

page_text: rifled bar working therethrough not fixed but capable of free rotation in one
direction only, this being effected by ratchet and pawl gear, so as to ensure a
step-by-step rotary motion of said piston and stamp at each downward stroke and
always in the same direction, as and for the purpose herein described and illus-
trated in Figs. 1 2 and 3 of the drawings.
2. In direct-acting. high-speed steam stamps such as herein referred to, the
combination with each stamp and mechanism for operating same, of external means
for imparting the step-by-step rotary motion to the stamp head in the same direction
at each downward stroke, comprising a rifled part formed upon or a rifled sleeve
fixed to the stamp stem working through a ratchet wheel with correspondingly
rifled boss suitably mounted and controlled by pawls, substantially as and for the
purpose described and illustrated in Figs. 4, 5 and 6 of the drawings.
Dated the 22nd day of March 1898.
For the Applicants,
J. C. CHAPMAN,
Chartered Patent Agent, 70, Chancery Lane, London, W.C.