Tables.
Year: 1887

page_text: Date of Application, 24th Oct., 1887
Complete Specification Left, 24th July, 1888
Complete Specification Accepted, 31st Aug., 1888
.
of Rotary Tables.
We ARTHUR STANLEY DOUGLAS, Mining Engineer, and RALPH HALL OUGHTON,
Mechanical Engineer, both of Peases West Collieries, by Darlington, in the County
of Durham, do hereby declare the nature of this invention to be as follows:-
This invention has for its object the screening, sizing, and cleaning of coal and
other minerals at Pits and Mines, and relates to the manner in which the coal or
other mineral being placed upon one, two, or more revolving tables, is sorted or sized
to facilitate cleaning.
The invention consists of one or more circular tables made of screen bars, in
sections, the openings to vary according the necessities of the work, and to be
adjustable when required. These tables are keyed upon a vertical shaft, and are
made to revolve at suitable speed by gearing, the coal or mineral being retained, or
permitted to pass through the first table on to the second, and so on to the next
fable if required, and after being examined and the rubbish or refuse taken out, the
whole either simultaneously or separately is swept off each table into or through
spaces left for the purpose near the vertical shaft, by a sweeper bar stretched into
position. The Coal or mineral falling down into a hopper or into the truck wagon
or other receptacle.
The tables may be of different diameters when preferred, the lower ones
increasing gradually in diameter, and may be caged in with a wire screen if found
necessary.
The coal in falling through the screening bars of the different tables is caught upon
wire screens and spread upon the table below.

page_text: COMPLETE SPECIFICATION.
Screening, Sizing, and Cleaning Coal and other Minerals by Means
of Rotary Tables.
We ARTHUR STANLEY DOUGLAS and RALPH HALL OUGHTON, of Pease's West
Collieries, near Darlington, in the County of Durham, 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:-
This invention has for its object the reception, sorting, sizing and cleaning of
Coal and other minerals at Pits and Mines, and relates to the manner in which the
coal or other mineral is operated upon by one, two or more revolving circular
tables, and is sorted or sized by this operation, to facilitate cleaning by hand picking.
The invention consists of one or more circular tables constructed to receive
arrangements of screen bars or gratings in separate segments, the openings or
interstices of which will vary according to the necessities of the case and the kind
and quality of the mineral or the purpose for which it is required.
These screen bars are made in two ways. Where the coal or mineral on the
upper or any subsequent table is required of large size, cast gratings of steel or iron
with suitably wide interstices, are made in segmental form, and dropped into segmental
recesses prepared in the frame of the table to receive them, so as to make up the
table top.
When the coal or other mineral on the lower tables is required smaller, these
segmental recesses are filled by a cast iron or cast steel frame and loose bars of
tapered section, of steel or iron curved to the varying diameters are inserted in the
frame and are kept in their places by through bolts and distance pieces. Thus varying
sizes of minerals can be obtained by varying the thickness of these distance pieces.
The rotary tables are each keyed upon a vertical shaft, and are made to revolve at
such a speed as shall be found convenient by suitable gearing, the coal or mineral
being retained on, or permitted to pass through the first table to the second and so on
to the next table if required, and after being examined and the rubbish or refuse
picked out, the remainder either simultaneously from the different tables or separately
from each is swept off into the centre or to the outside of the table by a sweeper bar
to each table stretched and fixed in position, and worked separately, or the whole
connected by coupling rod, and worked by hand lever at the same moment. The
coal or mineral falls down the centre of the table or at the outside thereof into trucks
or other receptacles.
The tables are of different diameters the first or upper one being the smallest the
others below increasing in diameter.
The coal in falling through the screening bars of the different tables is caught upon
sloping iron screens and directed and spread upon the table immediately below in
each case.

page_text: In the accompanying drawings
Fig. 1. shows a plan of half the upper table.
Fig. 2. shows a plan view of half of the upper and lower table, when two tables
only are used.
Fig. 3. shows a sectional elevation of our rotary screening machine with two
tables.
Fig 4. shows an enlarged plan of a segment of a table constructed with loose bars
and changeable distance pieces.
Fig. 5. shows an enlarged plan of the cast grating as used for coarse sifting.
Fig. 6. shows an enlarged longitudinal section of the frame of the upper table
with cross sections of the arm at 3 different points.
A. is the shaft.
B. is the upper table frame.
C. is the lower table frame.
D. is the sweeper bar.
E. is the sloping screen.
F. F. are distance pieces.
G. is the through bolt.
H. is the arm of the upper table frame.
I. is the recess to receive grating.
K. is a section of the arm H at the line O. P.
L. is a section of the arm Hat the line Q. R.
M. is a section of the arm H at the line S. T.
Having now particularly described and ascertained the nature of our said Inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. A rotary screening, sizing and cleaning machine with revolving tables, tier
above tier, and sloping screens between the said tables for coal and other minerals,
as herein explained and set forth.
2. The method of spreading the mineral over a large surface during the screening
operation, while still keeping it within a small compass by means of circular tables
one above the other, sloping screens and spreader bars, as herein explained and set
forth.
3. The construction of segmental frames containing separate curved bars with
varying distance pieces and through bolts, or of segmental gratings fitting into
recesses in the table frame of a rotary screening machine, as herein explained and
set forth.
4. The mode of delivering the mineral from table to table, or of discharging it
from each rotary table by means of sweeper bars, either by the centre opening or from
the outer edge of the table, as herein explained and set forth.
S. S. BROMHEAD,
97, Newgate Street, E.C.,
Patent Agent.