Improvements in Ore Concentrators.
Year: 1897

page_text: Date of Application, 30th Oct., 1897-Accepted, 23rd Apr., 1898
COMPLETE SPECIFICATION.
Improvements in Ore Concentrators.
I, FRANK LLOYD ROUDEBUSH, of 32, Old Jewiy, London, Promoter, do hereby
declare the nature of this invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
く
My invention relates to improvements in ore concentrators and consists of the
features hereinafter described and claimed, all of which will be fully understood
by reference to the accompanying drawings, in which
.
Fig. 1 is a side elevation of the apparatus, partly in section.
Fig. 2 is a top or plan view of the same.
Fig. 3 is a plan view of the table.
Fig. 4 is a side elevation of the same.
Fig. 5 is a cross section, of the table:
Fig. Gis a detail view of a lever forming a part of the operating mechanism.
Fig. 7 is a perspective view on a larger scale of one of the riffles.
Similar reference characters indicating corresponding parts in these views, let
the numeral 5 designate the table provided with longitudinal riffles 8 attached to
its upper surface. These riffles are of unequal length and angular in cross section.
The vertical or upwardly projecting part of the 'riffle is designated by the 'refer-
ence character 8, and the upper part which lies parallel with the bed of the table
is designated by the reference character 8°. The table tapers from the head
towards the foot, where it is narrowest. It is transversely inclined (see Fig. 5),
the gangue being 'discharged at its lower edge and the mineral at the tail thereof.
The riffles increase in length from the upper edge of the table downward, where
they are longest. The lowermost riffle extends nearly the full length of the table.
To the left of the riffle extremities (see Fig. 3) there is a triangular portion A of
the table which is smooth or free from riffles. The function of this smooth portion
of the table will be hereinafter described. The table has a longitudinal reciprocat-
inig movement; and is supported on rollers 7' mounted on a suitable stationary
support.
th..
The mechanism, for actuating the table will now he described. The extremity
of the table farthest to the left (see Figs. 1 to 4 of the drawings) will; for con-
venience of description in this specification, be termed the head; while the opposite
extremity is termed the tail of the table. To the head end of the table is attached
a keeper 9 which is engaged by one, extremity of a vertical lever 16 fulcrumied at 12
on a support 13 mounted on a stationary frame 14. The upper arm of the lever !0
is slotted (see Fig. 6) to receive a bolt 15, which holds a block TG in place on the
lever. This block carries an antifrictional roller 17 which engages the outer wall
of the keeper 9. The block 10 is adjustable for the purpose of changing the
bearing point on the keeper and thereby regulating the length of the table's stroke.
The lower arm of the lever 10 is provided with a bearing 18 which is engaged
by one extremity of a link 19. This link is connected at 21 with a link 20 forming
a toggle joint. One extremity of the link 20 engages 'a bar 22 attached to the

page_text: stationary frame. The pin 21 connecting the two toggle parts also passes through
one extremity of a pitman 23, whose opposite extremity is connected with a
wrist 24 on a crank 25 carried by a shaft 26. journalled in an upright support 27
mounted on the stationary frame 14. The shaft 26 is provided with a pulley 28
which may be connected with any suitable motor for operating the mechanism.
The outer extremities of the toggle are open, being simply recessed or forked to
engage the bearings 18 and 22 respectively. Hence, as the shaft 26 is rotated, the
toggles only impart the backward movement to the table or move it toward the left
(see Fig. 3); the forward or reverse movement is effected or imparted by the
recoil of a spring 29, which is compressed or placed under tension by the table
during its backward movement.
In the operation of the machine, the material to be treated is discharged in the
form of pulp upon the upper left hand corner of the table (see Fig. 3). The gangue
passes transversely downwardly over the angular longitudinal riffles and is dis-
charged over the lower edge of the table which, as before stated, is transversely
inclined. All the mineral, together with a portion of the gangue is first caught
by the riffles, and under the influence of the table's motion is carried longitudinally
toward the foot of the table, until it reaches the smooth or unriffled portion A of
the table, where it is acted on by the water which effects a perfect or approximately
perfect separation of the gangue from the mineral. As the material caught by the
uppermost and shortest riffle passes to the portion A of the table, the action of the
water, which is fed to the upper edge of the table, carries the gangue downward
to the next riffle, while the mineral remains on the smooth portion A and is carried
towards the tail of the table, where it is finally discharged. It is expected that
some of the mineral caught by the uppermost and shortest riffle will be carried
downward with the gangue to the next riffle which is longer. After leaving this
last named riffle and passing to the smooth or unriffled portion of the table, the
water again acts on the material and carries the gangue downward to the next riffle,
leaving the clean material on the smooth portion of the table. If any mineral
escapes with the gangue the second time, it will be caught by the riffle next below
and again subjected to the separating action of the water as soon as it reaches the
smooth portion A of the table. In this manner, the material is carried transversely
downward and longitudinally forward, the gangue being discharged at the lower
edge of the table, completely impoverished of its mineral values, while the latter
are discharged at the foot or tail of the table. A portion of the gangue, that is to
say, the lighter part thereof, passes over each riffle in succession from the shortest
or uppermost to the longest or lowermost riffle. The mineral and the heavier
gangue are caught by the riffles and finally separated on the smooth portion A of
the table. This combination in a concentrating table, of riffles of varying length
for catching the mineral, and a smooth, plain, or unriffled portion at the extremities
of the riffles where the final separation is effected through the action of the water,
is believed to be entirely new in an apparatus of this class. A riffle is the best
means of catching the mineral; while a smooth, plain, or unriffled surface is the
best for effecting the separation of the mineral from the gangue caught with the
mineral by the riffles, the separation being effected by the action of water.
While I prefer to employ the angular riffle shown and described in this applica-
tion, I do not limit the invention to any special construction of riffle. The function
of the angular riffles will now be described in detail. The part 8 of the riffles
would be sufficient alone to catch the larger and heavier particles of mineral; but
some of the more, minute particles would be forced over the riffles and carried
downward with the gangue and perhaps finally lost, were it not for the part 8° of the
riffles which checks this tendency and allows specific gravity to prevail, the same
as in hand panning. It is well known that the finest particles of mineral can be
saved by hand panning. The specific gravity of the finest particles of gold is, of
course, the same as the largest nugget, and if the proper conditions exist, the
minute particle can be saved as well as the nugget. The object of my angular
riffles is to produce the conditions necessary to save, not only the largest, but also

page_text: the finest mineral particles. Under ordinary conditions, these fine particles, when
acted on by a current of water, are carried along with the water, and consequently
Flost with the gangue. The upper part 8° of my riffle checks the tendency of these
light particles to pass over the riffles with the water. Hence, they are confined
by the bed of the table below the part 8° of the riffles above, while the part 8° of
the riffles checks their downward movement. Hence, under the influence of the
table's movement or vibration, the mineral particles, both fine and coarse, are caught
by the riffles.
It will be observed by an inspection of my operating mechanism that the length
of the table's stroke may be regulated without changing, altering or interfering
with the quality of the movement imparted by the toggle. With other toggle
movements, as applied to this class of machines, the length of stroke is regulated
by changing the point where the lower extremity of the connecting rod or pitman
is attached to the toggle. This is equivalent to changing the length of the pitman
and, of course, not only changes the length of the table's stroke, but also the
quality of the movement. For instance, if the pitman be made shorter, the point
where the toggle links are connected must move further upward but not so far
downward, and vice versa. In other words, by changing the length of the pitman
(or changing the point where it is attached to the toggle, which is the same thing),
the angle of the links becomes greater when the table has reached its limit of move-
ment in one direction, and less when the table has reached its limit of movement
in the opposite direction. Hence, in such constructions, the speed of the table at
a given point in its stroke varies as the length of the stroke is changed.
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. A transversely inclined concentrating table having a movement whose ten-
dency is to carry the material longitudinally forward toward the tail or foot of the
table, said table being provided with a number of riffles extending longitudinally
a portion of the distance from its head towards its foot, said riffles varying in length
for the purpose specified, the table having a smooth, plain, or unriffled portion
extending from the extremities of the riffles toward the tail of the table, whereby
the inaterial as it leaves the riffles is subjected to the action of the water on the
smooth portion of the table and the final separation of the mineral from the gangue
effected.
2. A transversely inclined concentrating table having a number of longitudinal
riffles extending a portion of the table's length from the head toward the foot,
said riffles being of unequal length, the uppermost heing the shortest while the other
rifiles increase in length from the upper edge to the lower edge of the table, the
table having a plain or unriffled portion lying at the extremities of the riffles and
alapted to receive the material caught by the riffles.
3. The combination of a transversely inclined concentrating table having a num-
ber of longitudinal riffles of unequal length extending from the head toward the
tail of the table, said riffles increasing in length from the upper toward the lower
edge of the table, said table being provided with a plain or unriffled portion at the
extremities of the riffles, and means for imparting to the table a longitudinally
reciprocating movement comprising a toggle, and operating pitman and a lever,
one link of the toggle engaging one arm of the lever, while the other arm of the
lever is connected with the head of the table.
4. The combination of a transversely inclined concentrating table having a num-
ber of longitudinal riffles extending from the head toward the foot of the table, the
table being provided with a plain or unriffled portion located at the extremities
of the riffles, and means for imparting to the table a longitudinal reciprocating
movement comprising a toggle joint, an operating pitman and a lever, one link of
the toggle engaging one arm of the lever while the other arm of the lever is con-

page_text: nected with the table and provided with an adjustable roller adapted to engage a
keeper carried by the table."
5. The combination of a transversely inclined concentrating table having a
series of longitudinal riffles extending from the head toward.the. foot of the table,
the table being provided with a plain or unriffled portion extending from the riffle
extremities to the foot of the table, and means for imparting to the table a longi-
tudinally reciprocating movement, said means comprising a toggle joint, an
cperating pitman and a lever, one link of the toggle engaging one arm of the lever,
while the other arm of the lever is connected with the table, and provided with an
adjustable roller, said roller being mounted on a block adjustably attached to the.
lever.
6. The combination of a transversely inclined concentrating table having a 1 um-
ber of longitudinal riffles extending from the head toward the tail of the table,
the table being provided with a plain or unriffled portion located at the extremities
of the riffles, and means for imparting to the table a longitudinally reciprocating
movement, comprising a toggle joint, an operating pitman and a lever, one link
of the toggle engaging one arm of the lever, while the other arm of the lever is
connected with the table and provided with a vertical slot and a block held in place
by a bolt passing through the slot and carrying an anti-frictional roller engaging
a keeper on the table.
7. The combination of a transversely inclined concentrating table having a series
of rifles extending longitudinally from the head toward the tail of the table, said
riffles being of unequal length, the uppermost being the shortest and the riffles
increasing in length from the upper to the lower edge of the table, the table being
provided with a plain or unriffled portion of suitable area located at the extremities
of the riffles, means for feeding the material to the upper portion of the table's
head, means for discharging water on the upper edge of the table, and suitable
means for imparting to the table a longitudinally reciprocating movement of a
.character adapted to move the material from the head toward the tail of the table.
Dated this 30th day of October 1897.
ALLISON BROS.,
Agents for the Applicant.