Improvements in Roller Screens for Sorting or Screening Coal and the like.
Year: 1897

page_text: Date of Application, 20th May, 1897-Accepted, 26th June, 1897
COMPLETE SPECIFICATION.
Improvements in Roller Screens for Sorting or Screening Coal and
the like.
A communication to me from BRUNO, BARON VON STEINÄCKER, of Lauba 1,
Silesia, in the Empire of Germany, Mine Owner.
I, EDMUND EDWARDS, of the Firm of Edwards and Co., Patent Agents and
Engineers, of 65 and 66, Chancery Lane, in the County of Middlesex, 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, and accompanying drawing, that is to say :-
The different forms of roller screen apparatus heretofore usel for the purpose of
sorting and screening coal and the like, have always been constructed on the
supposition that it is absolutely necessary that the openings or passages
between the rollers should be of a shape closed all round. This is not,
however, in all circumstances the case, though coal generally breaks into
pieces of cubical or similar shape, pieces having a flat shape being seldom
met with.
By the present invention the shape of the openings through which the coal or
other material passes between the rollers of the apparatus is made zigzag, and in
this manner the following advantage is obtained.
Under the supposition that each single opening or passage is to be closed in or
surrounded on all sides, the projections upon each two adjoining bars are made to
fit at their points close up against each other. In this way it is evidently
impossible for pieces of coal to fall through, if they exceed in width that of
the opening, as they cannot move laterally since the projections upon one roller fit
close to those of the adjoining ones. By the present invention, a certain amount
of such lateral movement is possible.
The accompanying drawing illustrates (in plan) two forms of roller screening
apparatus constructed according to this invention.
In the form of arrangement shewn in Figure 1 the zigzag shape of the opening a
is obtained by making the projections b, formed of a cylindrical part and two conical
parts connecting it with the body of the roller, upon one roller come opposite to
the recesses c between the projections upon the adjoining rollers. In order to
prevent more certainly the pieces of coal from being carried, by the proportionally
greater speed of revolution of the outer parts of the projections, over the parts of
the spaces corresponding with their size, and to direct the pieces of coal in the
proper direction to facilitate their automatic passage through the openings, the
projections and recesses between them may be well rounded, as shewn in Figure 2
at b and c, or formed of shallow zigzag lines, as shewn in dotted lines.
In the form shewn in Figure 1 the surfaces d and d', and in the form shewn in
Figure 2 the surfaces b, c, d, may be grooved.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what [
claim is :-
:-
1 In roller screens, for sorting or screening coal and the like, the method of

page_text: making the openings a between the several rollers, zigzag in form, the
projections (Figure 1) or b' (Figure 2) upon one roller being opposite to
the recesses c or cupon the adjoining rollers, substantially as described and
illustrated.
Dated this 20th day of May 1897.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.