Improvements in Sieves.
Year: 1896

page_text: Date of Application, 11th Jan., 1896-Accepted, 15th Feb., 1896
COMPLETE SPECIFICATION.
Improvements in Sieves.
I, HERMANN DEMANT, of Leipzig-Connewitz, in the Kingdom of Saxony,
German Empire, Manufacturer, 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 refers to sieves, especially flat or horizontal ones; my improve-
ments in said sieves relate to means for quickly and securely stretching the gauze
or cloth of the same. I attain that object by bending the rim of said gauze rect-
angularly off so as to lie parallel to the mantle of the sieve, and by arranging
inside the latter an expansible frame situated close to the gauze or cloth, and
bearing upon said bent-off' rim, and having a mechanism by means of which said
frame may be expanded so as thereby to stretch the said gauze.
I have shown one form of construction of my novel device in the accompanying
drawing, in which similar letters denote similar parts throughout the different views
and in which :-
Figure 1 is a vertical section through my improved sieve;
Figure 2 is a horizontal section taken on line 4-5 of Figure 1, and
Figure 3 is a slightly modified form of the expanding screw C.
The expansible frame is in the form of construction shown, which is formed by a
band-like ring A, the end a¹ of which laps over the end a 2. Said ring A is at or
near it ends provided with two projections b' b2; the projection b¹ carries the
screw C, the quadrangular head c¹ of which lies against the projection 62.
The frame or ring Å bears upon the bent-off rim of the gauze or cloth B, and is
expanded by turning the screw C by means of a suitable key adapted to be put
laterally upon the head c¹; the direction of turning is, as a matter of course, to be
such a one, that the projection moves away from the projection 62. The ring A
is thereby powerfully pressed upon said beut-off rim of the gauze, and the latter is
thus stretched. If the gauze or cloth is to be exchanged, the screw C c' need simply
be turned in the reverse direction, when the expanded ring will contract by reason
of its elasticity.
Said contraction may, however, be effected also compulsorily by using a double-
headed screw, such as shown in Figure 3, in which the right-hand end proper of
the screw is furnished with the auxiliary head c 2. The projection 62 is, as a
matter of course, provided with a slit instead of with a simple aperture as in the
form of construction first described.
To secure the gauze and ring fully against axial displacement, I prefer to provide
the mantle D of the sieve with two inner collars d' d2, and to arrange said parts
between said collars. The latter may, as a matter of course, be replaced by pro-
jections or ledges of other configuration, and instead of securing the gauze and
ring from the upper and lower side, it will in many cases be sufficient to do that.
only from the lower one.
It will, furthermore, be clear to everyone versed in the art in question, that the
screw C c¹ or C c c 2 may well be replaced by any other suitable mechanism, may
be a fixed screw with movable nut, an eccentric disk, a toggle-lever, and the like.
Moreover, the frame A need not indispensably consist of one piece only, but may
be composed of two or more, especially if the sieve is not a circular, but, for
instance an angular one.
The several parts or portions of the ring or frame may be connected by wires E
secured to ears e¹ of said ring or frame.

page_text: 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. In a sieve, the combination with the gauze having its rim bent off so as to lie
parallel to the mantle, of an expansible frame arranged inside said mantle close to
said gauze, and adapted to bear upon said bent-off rim; means for expanding said
frame, for the purpose as described.
2. In a sieve, the combination with the gauze having its rim bent off so as to lie
parallel to the mantle, of an expansible frame arranged inside said mantle close to
said gauze, and adapted to bear upon said bent-off rim; means for expanding said
frame, and for securing it against axial displacement, for the purpose as described.
3. In a circular sieve, the combination with the gauze having its rim bent off so
as to lie parallel to the mantle, of an annular frame broken at one place, and
arranged inside said mantle close to said gauze; said frame having projections
extending inwards, and situated near to the broken place; means for expanding
the said frame so as to press the latter upon said bent off rim, said means being
carried by said projections, for the purpose as described.
4. In a circular sieve, the combination with the gauze having its rim bent off so
as to lie parallel to the mantle, of an annular frame arranged inside said mantle
close to said gauze, and adapted to be expanded so as to press upon said bent-off
rim; a collar arranged so as to form a support for said rim; means for expanding
the latter, for the purpose as described.
5. In a circular sieve, the combination with the gauze having its rim bent off so
as to lie parallel to the mantle, of an annular frame arranged inside said mantle
close to said gauze, and adapted to be expanded so as to press upon said bent-off
rim; collars arranged so as to prevent axial displacement of said ring and gauze in
either direction, for the purpose as described.
6. In a circular sieve, the combination with the gauze having its rim bent off so
as to lie parallel to the mantle, of an annular frame broken at one place, and
arranged inside said mantle close to said gauze; said frame having projections
extending inwards, and situated near to the broken place; a headed screw having
its nut part formed by one of said projections, and bearing with its head against
the other of the said projections, for the purpose as described.
Dated this 11th day of January 1896.
HERMANN DEMANT,
By Geo. Thos. Hyde,
1, Broad Street Buildings, Liverpool Street, London, E.C.,
Agent for the Applicant.