Improvements in or connected with Grinding Pans for Granulatable Materials.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in or connected with Grinding Pans for Granulatable
Materials.
I, HERBERT HAVELOCK HODGSON, of 46, Spencer Place, Leeds, in the County of
York, Quarry Owner, do hereby declare the nature of this invention to be as
follows:-
This invention has reference to the class of revolving grinding pans with solid
bottoms in which the usual rollers or edge runners are used for crushing granu-
latable material such as sand and the like.
The object of the invention is to provide pans such as the above with a suitably
agitated screening apparatus, which shall discharge the properly crushed material
on the outside of the pan, whilst that insufficiently dealt with is returned to the
pan for a further run under the rollers.
I find that a considerable advantage accrues from the prompt removal of the
crushed material, which allows the rollers to exert their power on the larger sized
material without being "cushioned," as it were, on that already reduced in size.
I carry our my object as follows:-I mount a suitable screen, provided with a
mesh of the desired size, at a moderate slant (that is moderately near the horizontal
line) and with its lower edge above the top edge of the revolving pan. The upper
part of the screen extends outwardly, so that any material passing through the
mesh may fall outside the pan, whilst any thing rolling off under vibration falls
back into the pan. The screen is mounted on a vibratable frame, pivoted preferably
on the standards of the machine itself. This frame may be so balanced that it
stands in its slightly lifted and tilted position when it carries no weight of material
on its mesh, and only when weighted falls back into its full gear or best working
position, as explained hereafter. From this pivoted screen a leg extends down-
wards and inwards towards the driving shaft of the revolving pan, and on this
shaft is fixed a suitable cam that engages with the toe of the aforesaid leg.
Hence at every revolution of the driving shaft a lift and shake is given to the
and this may be made violent enough to throw the material up off the
screen; another shake may take place on the rebound of the screen from off its
stops in the act of falling back.
screen,
From what is here set out it follows that an unladen screen can be made to
balance itself with its leg out of reach of the revolving cam or striking pin, and so
remain at rest when not required in action. There may be, of course, more than
one cam, according to the opportunities allowed for their introduction by the
build of the revolving pan, but one cam will do, and so will any ordinary build of
The screen
may be mounted so that its slant may be adjusted, and loose
secondary frames for interchanging different sizes of mesh may be arranged.
All that now remains for working this apparatus is a means of lifting the
crushed and semi-crushed material out of the pan and on to the agitating screen.
pan.

page_text: A simple mode of effecting this is to sling or otherwise fix up a balanced shovel
or scoop in a suitable position for allowing the attendant to fower the scoop into
the stream of the material and then lift it and discharge its contents on to the
screen.
Where it is desired to save the cost of this attendant, then a suitable set of
paddles or other appliance, worked from the driving shaft may be caused to revolve
or vibrate in the required direction to deal with the stream of the material and
lift it out automatically; having regard, however, to the grit that has to be
contended with, the amount of manual labour called for by the scoop arrangement
is not a paramount objection.
Improvements in or connected with Grinding Pans for Granulatable
Materials. .
I, HERBERT HAVELOCK HODGSON, of 46, Spencer Place, Leeds, in the County of
York, Quarry Owner, 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 has reference to the class of revolving grinding pans with solid
bottoms in which the usual rollers or edge runners are used for crushing granu-
latable material such as sand and the like.
The object of the invention is to provide pans such as the above with a suitably
agitated screening apparatus, which shall discharge the properly crushed material
on the outside of the pan, whilst that insufficiently dealt with is returned to the
pan for a further run under the rollers.
"
I find that a considerable advantage occurs from the prompt removal of the
crushed material, which allows the rollers to exert their power on the larger sized
material without being "cushioned as it were, on that already reduced in size.
In order to fully explain my invention have annexed a drawing on which
Fig. 1 is a plan view showing the principal parts of a grinding pan to which I
have added my screening apparatus, whilst Fig. 2 is a corresponding elevation;
in both of these figures ordinary parts of the grinding-pan itself are here and there
omitted or broken off in order to show portions of my apparatus more clearly.
Fig. 3 is a sectional elevation showing my discharging paddle, etc., whilst Fig. 4
is a corresponding side elevation of the same details. The same letters refer to
the same parts in all the figs., and arrows point.out the direction of revolution.
I carry out my object as follows:-I mount a suitable sieve or screen A,
provided with a mesh of the desired size, at a moderate slant (that is, moderately
near the horizontal line) and with its lower edge A¹ above the top edge of the
revolving pan B. The upper part of this sifting screen extends outwardly to the
right hand in the drawing, so that any material passing through the mesh may
fall outside the pan, whilst anything rolling off under vibration falls back into the
pan. The screen which is shown surrounded by a hood A² is mounted on. a
vibratable frame C, pivoted preferably on the standards of the machine itself,
as at D for instance. This frame may be so balanced, say, with weights at C',
that it stands, when it carries no weight of material on its screen, in a slightly
lifted and tilted position, and so that only when weighted can it fall back into its

page_text: full gear or best working position, as explained hereafter. The position shown on
the drawing is that of full gear due to a laden screen.
From this pivoted screen a leg E extends downwards and inwards towards the
driving shaft F of the revolving pan, and on this shaft is fixed a suitable cam F1
that engages with the toe of the aforesaid leg. Hence at every revolution of the
driving shaft a lift and shake is given to the screen, and this may be made violent
enough to throw the material up off the screen, another shake taking place on the
rebound of the screen from off its stops or banging blocks G, in the act of falling
back. To strengthen the position of this leg a straining bolt E' connects it with
the counter balancing arm of the frame C as shown.
From what is here set out it follows that an unladen screen can be made to
balance itself with its leg out of reach of the revolving cam or striking pin, and
so remain at rest when not required in action. There may be, of course, more than
one cam, according to the opportunities allowed for their introduction by the
build of the revolving pan, but one cam will do, and so will any ordinary build of
pan. The front of the screen where it bends over the pan is provided with an
apron A3 as shown in Fig. 3, and this must extend far enough down to fully
overlap the edge of the pan even when the screen is tilted to its highest position,
otherwise an undesirable escape hole for particles not sufficiently granulated is
left.
The screen may be mounted so that its slant may be adjusted, and loose
secondary frames for interchanging different sizes of mesh may be arranged.
The bottom of the screen may have an extra cross slant given to it so as to discharge
the "large" nearer to the roller next in order, as shown by the double arrow
in Fig. 1.
All that now remains for working this apparatus is a means of lifting the
crushed and semi-crushed material out of the pan and on to the agitating screen.
A simple mode of effecting this is to sling or otherwise fix up a balanced shovel
or scoop in the usual way in a suitable position for allowing the attendant to
lower the scoop into the stream of the material and then lift it and discharge its
contents on to the screen.
Where it is desired to save the cost of this attendant for working this balanced
shovel, then a suitable set of paddles, or other appliance, worked from the driving
shaft may be caused to revolve or vibrate in the required direction to deal with the
stream of the material and lift it out automatically; having regard, however,
to the grit that has to be contended with, the amount of manual labour called for
by the scoop arrangement is not a paramount objection to its use.
The position of my discharging paddle wheel H, is shown in Figs. 1 and 2,
and further details of it, and its spade and share, which guide and bring the
material to it, are shown in Figs. 3 and 4. The paddle wheel is mounted on
a shaft H which is purposely made light enough to allow the whole to spring
upward and out of the way of anything too large for it to deal with easily. This
shaft, whose bearings are in the end frames J, J, extends across the machine and
has a pulley K which is driven by a belt from another pulley, L, on the driving
shaft F. An advantage in this belt-drive lies in the fact that the belt may be
arranged to slip rather than allow the paddle to break itself should it become
completely choked. The paddle revolves in the direction shown and is fitted
with renewable shoes at the ends of its arms. These shoes should be so angled
that they strike the material somewhat obliquely in the manner shown by the
thick dotted line in Fig. 1, which represents the under blade in acțion. The
spade M extends underneath the paddle while the share N both directs the
material to it and forms an inclined guiding path up which the material is pro-
jected, without interfering with that falling off the screen back into the pan.
Should anything be projected too far it is caught by the hood A² before mentioned.
Both the spade and the share, which if desired may be formed in one piece, are
supported by the general stay ( which extends across the pan and supports the
ordinary guiding shares necessary for the crushing rollers; a stay bolt P further

page_text: steadies the share at its proper inclination for successfully guiding the material
up to the screen. The main parts of the grinding pan which is here taken as an
illustration will be easily followed, Q being the driving pulley on the shaft F
which carries a pinion (not shown) gearing into the bevelled wheel under the
pan J, J, are end frames, resting on foundation timbers R, R; S, S, are the
crushing rollers, and T the central vertical shaft.
I make a simple but important modification in the arrangement and mode of
using my granulating apparatus when the pan is fed with material a fair pro-
portion of which is sufficiently granulated to make a preliminary sifting desirable
In this case I mount another screen Z on the opposite side of the rocking frame C
as shown in dotted lines on Figs. 1 and 2, preferably pivotting the rocking frame
in the centre of the machine. I also arrange when necessary two rocking legs or
levers E or their equivalent, and if such be required an additional agitating cam,
completing the whole with additional stops or banging blocks under the new
screen. On to this additional screen, which has no hood, I feed the material for
granulating, and the preliminary shake causes the "small" to pass through
the seive and fall outside the pan, whilst the remainder rolls off into the pan, in
the same way as the other "large material does off the other screen. It is
obvious that by this simple addition one handling of the material at the outset
relieves the pan from the very first of any superfluous
"small and diminishes
the cushion" which such small"
"would otherwise have set up. The rest
of the process is the same as in the one screen arrangement already described,
that is to say, as the granulating proceeds the material is constantly lifted out and
on to the screen, when all "small" is discharged outside whilst the "large" rolls
back for further crushing. It will be understood that modifications in this
arrangement may be required to be made to suit different builds of pan, and these
may be easily arranged by following this description, without departing from the
spirit of the invention.
"
"
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. A solid-bottomed grinding pan fitted with a specially arranged and auto-
matically worked sifting-screen provided with an apron front, substantially as
described and shown, with the object and for the purpose set forth.
2. A solid-bottomed grinding pan fitted with a specially arranged and auto-
matically worked sifting-screen provided with an apron front, together with a
self-acting discharging paddle wheel and its accessories, substantially as described
and shown, with the object and for the purpose set forth.
3. A solid-bottomed grinding pan, fitted as described in Claims 1 and 2, together
with an additional automatically worked sifting-screen for receiving the material
and giving it a preliminary screening, substantially as described and shown, with
the object and for the purpose set forth.
Dated this 13th day of Avril 1899
WM. SNOWDON,
Agent for the Applicant,
24, Basinghall Street, Leeds, Yorks