Improvements in Ore Stamps.
Year: 1888

page_text: Improvements in Ore Stamps.
I, ALFRED DAVY, of 14, New Exchange Buildings, Sheffield, in the County of
York, 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 statenient:
My Invention has for its object to reduce the wear and tear, and effect an economy
in the working of ore crushing stamps worked by cam and tappet motions and
commonly known as gravitation stamps. The tappets although adjustable to com-
pensate for wear of the shoes and dies have heretofore been rigidly fixed to the stems
of the stamps and have been acted on directly by the cams which therefore raise the
stamps more or less suddenly and consequently meet with a resistance corresponding
to the weight and inertia to be overcome each time that they start the stamps from a
state of rest. The result is that each upward motion or lift of the stem is accom-
panied by a more or less violent blow between the cam and the tappet which causes
vibration throughout the whole of the machinery which tends to destroy it more or
less rapidly, according to the speed of working the stamp.
My Invention consists in interposing elastic cushions or springs between the cams
and the stamp stems so as to modify or lessen the blow and cause the cams to set the
stamps in motion more gradually.
Reference is to be had to the accompanying drawing forming part of this specifica-
tion wherein I have represented two modifications of my invention. The same letters
of reference serve for like parts in all the figures.
A is the stem of one of the stamps of a battery and B is the ordinary tappet
secured adjustably thereto by two cotters on one side of the tappet which are driven in
D

page_text: and impinge upon the side of the stem in the ordinary manner, so that it may be
shifted up or down the stem, as required, according to the state of wear of the shoes
and dies. It however, no longer acts as a tappet, but merely forms an abutment collar
for a spring cushion C which is interposed between the said collar B and the real
tappet D. This tappet is constituted by a flange D of about the same diameter as the
ordinary tappet and formed on the upper end of a tube or socket d fitted to slide
freely up and down on the stem A the cam (which is not shewn) acting on the under-
side of this flange at one side of the tube d. The said tube is of sufficient length to
ensure lateral stability and easy sliding motion of the tube, and also to bring the
lower end of said tube (which is also flanged) clear of the cam. This tube may either
be slipped into position on the stem, or it may be divided longitudinally into halves,
which are bolted together upon the stem, as will be readily understood.
The elastic medium C may be of india rubber or steel preferably the former, as
shewn in figure 1. in the form of rings a threaded or otherwise placed on the stem A
alternately with metal washers c¹ to distribute the pressure as nearly as possiblo
equally throughout the several elastic rings. These rings and the intervening washers
may be cut through radially at any point, so that by temporarily deflecting the
severed portions in opposite directions, they may be slipped laterally on to the stem A.
Thus, when the tube d is made in halves, as above mentioned, my invention may be
applied to a battery without dismounting any of the parts.
Instead of using india-rubber, I may employ metal springs as shown in figure 2
which may consist either of "buckled " discs of steel or of spiral springs.
To secure rotary motion of the elastic cushion with the tappet D and collar B, these
latter may be radially grooved in all directions on their acting faces if an india-
rubber cushion is used, or by pinning the spring, if of steel, to the collar B and the
tappet D.
As the object is, in any case, to prevent individual rotary motion of the parts, but
to cause the stem of the stamp to revolve about its vertical axis so as to equalize wear,
this rotary motion may be got by a groove and feather connection between the sliding
tube d and the stem A which will cause the latter to turn with the former under the
frictional contact of the cam without preventing the sliding motion of the tappet on
the stem.
To retain the sliding tappet in its proper position to be acted on by the cam, its
motion is limited by a collar E and to cushion it, when upon the escape of the cam
from beneath it it falls to its normal position, an elastic medium G is introduced
between said collar and its lower end which is flanged as at d¹. This elastic medium
may be either india-rubber discs with intervening metal washers, or steel springs as
before described for the upper cushion C, but I may prefer to use india-rubber at C
and steel at G. Both the flange D and collar E are recessed so as to receive the
adjacent ends of the clastic cushions. The collar E is adjustably secured in the same
way as the abutment B, or it may be made in halves cottered together tightly on the
stein A.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declaro that what I
claim is:-
1. The application between the cam and the stamp stems of a gravitation stamp
battery, of springs so as to modifiy the violence of the blow between the cams and
tappets, and cause the former to raise the stamps more gradually at the commencement
of each lift, substantially as specified.
2. The combination with the stem of a stamp worked by cam and tappet motion, of
a tappet sliding up and down on the stem, as described and an elastic cushion inter-
posed between such sliding tappet and an abutment collar adjustably 'fixed on the
stem.
3. The combination with the stem of a stamp worked 'by cam and tappet motion, of
a 'tappet 'formed of a flanged tube 'fitted 'to slide on the stem and transmit vertical

page_text: motion thereto through an elastic cushion and abutment and circular motion through
a groove and feather connection, as specified.
4. The combination with the stem of a stamp worked by cam and tappet motion, of
a sliding tappet thereon, as described, and of elastic cushions and adjustably fixed
abutments therefor both above and below the said tappet, as and for the purposes
specified.
A. DAVY.
By A. M. & Wm. Clark,
53, Chancery Lano, London,
Patent Agents.