Improvements in Sifting Devices.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Sifting Devices.
I, ANTON STEHLE of Caunstatt in the Kingdom of Wuerttemberg, Empire of
Germany, Farmer, do hereby declare the nature of this invention and in what manner
he same is to be performed, to be particularly described and ascertained in and by the
following statement :-
The object of this invention is a flat sieve having sifting wires lying side by side
and parallel to the length sides of the sieve, part of said wires being seenred at certain
equal distances from each other to cross-stays or bars attached to the sieve frame,
while the other part of the wires is likewise secured to cross stays or bars which are
adapted to be at pleasure so raised or lowered by means of the hereafter described
contrivance as to render the clear width between the sifting wires adjustable within
certain limits, while remaining uniform in any position relatively to each other.
Referring to the
he sccompanying drawings Sheet I
like parts
Hla lottaus damata
like parts.
Fig. 1 is a plan,
Fig. 2 a side view,
Fig. 4 a cross section of the improved device, while.
Figs. 3, 5, 6 and 7 illustrate on an enlarged scale part of the contrivance for raising
and lowering the sifting wires. In the drawings sifting wires of circular cross section
are represented as being employed; but also wires of quadrangular or any other
suitable cross section may be employed with the same facility. Furthermore the first,
fifth, niuth etc. sifting wires d' are in the drawing supposed to be attached to the cross
bars D', which on their part are secured to the sieve frame S, while the interme:liat>>
sifting wires, namely the second, sixth, tonth etc. are fastened to the cross bars D'
which are movable upwardly, the intermediate wires d³, namely the third, seventh,
eleventh etc. to the cross bars D³ movable vertically downwards, and the wires d',
namely the fourth, eighth, twelfth etc., to the cross bars D' which are again movable
upwardly.
Provision is made relatively to the raising of the cross bars D' and D, that to a
certain height these bars are lifted the same distance, while the descending cross
carriers D³, together with the sifting wires ³ do not undergo at first any alteration of
position. When the sifting wires d' and d² are so far raisel that their wean distances
from and d are equal to the distance between and d', the wires d' and to he
raised, must, in order to produce greater clear widths, be further raised, while the
sifting wires d³ i.e. the cross bars D must be lowered or pressed down. The sorting
proper is now produced only by the sifting wires d³ and d while the wires d' and
are so far lifted up as to allow the material or mixture to be sorted to reach
unimpededly the lower sifting wires. For this purpose the sifting wires d³ must be
lifted to their highest position.
To attain the above ends, the following essential arrangements are required:-
Of the superposed cross bars D¹, D², D and D³ which carry the sitting
wires d' d² dd, the bars D1 D2 and D³ are so rivetted or otherwise secured at both
ends to the cross bar carriers A', A², and A³ provided outside and along the sifting frame
as to cause, when raising and lowering the said carriers, also the sifting wires to be
raised or lowered. In order to obviate a longitudinal displacement of the cross bar
carriers, groove-like guidings ƒ for the same are provided at the four corners of the
sieve.
The raising or lowering of the cross bar carriers is effected by means of a contrivance
illustrated in Figs. 3, 5, 6 and 7. The sieve frame S is suspended by means of the
supports i from two suspension shafts T of the sieve which shafts carry rigidly secured
LDS37

page_text: thereto four cam disks E. The latter are fitted on one side with so-called lifting
nozzles e¹ serving to raise the cross bar carrier A' while on the other side two pivots
with rolls and are provided diametrically opposite each other, said rolls are
destined to lift A¹ and lower A' respectively.
The peg or nozzle el of the eccentric disk E engages, on the turning of the latter, !
under a nozzle of the lifting piece a² secured to the cross bar carrier A² and raises the
said piece together with A, thereby also lifting the cross bar carrier A resting freely
on A. When a certain height is attained, the tip or point of the peg e¹ arrives under
a curve-shaped projection of a nozzle of a³ and effects no further lifting of A' also on
further revolution of the cam disk E. But the rolls r¹ and 3 of the latter come now
in action by the roll, catching under a lifting piece a', bent round at the top, of the
cross bar carrier A', thereby raising the latter further, while presses on a sinking
piece of the cross bar carrier A and thereby lowers the latter.
The cross bar carrier A³ is returned to its normal position, by the action of the two
springs and the carriers A' and A' with appurtenances redescend through their
own weight.
In order to cause a uniform raising and lowering of the sifting wires d' d' and d³ to
take place in all parts of the sieve, the four equal excentric disks E are made to occupy
exactly the same position on the suspension shafts T and their displacement is effected
by means of two levers K lying in the same direction and connected with each
other by a rod r. The said levers K are detained in a certain position by aid of a
segmental hoop B secured to the sieve frame and in which the one of the
two cranks K is held fast by a pins which is placed through holes provided in
hoop B.
To allow the lifting of the cross bar carriers together with the cross bars and
sifting wires which in larger sieves sometimes represent a considerable weight-
to be effected with facility, one of the two suspension shafts T carries a horizontal
lever H having at its extremity a counter poise G of corre-pondingly determined
weight or size.
The improved adjustable flat sieve works as follows:-
:-
The mixture or material to be sorted is brought through a particular feed device in
a uniform layer on the rocking sieve, the whole of the sieve wires d' d' d' d³ lying in
the some plane, be, ovenpying their narrowest position. The smallest-sized material
which falls first through, having been collected in a suitable receptacle, the sitting
wires d' to dare, by means of the cranks K and other contrivances referred to,
raised and lowered i.e. the clear width of the sieve changed at certain intervals of time
and thus gradually enlarged until the coarsest material has passed through.
Subsequently the cranks K are returned to their normal position so as to re-establish
the narrowest widths of sieve and the sifting process is repeated with a new quantity
of material. The changing of the sieve widths may be effected by hand or auto-
matically and intermittently by means of a suitable device for this purpose.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
An adjustable flat sieve in which the sifting width can be changed through successive
uniform raising and lowering of parallel wire systems d' d' d³ relatively to a stationary
wire system d³, each of two cam disks E, which are rigidly mounted on the sieve
suspension shafts T and coupled by levers K and connecting rod e, being adapted to
operate by means of a pegel and two rolls the cross bars D D D³ of the
movable wire systems in the manner substantially as illustrated and described.
A TY V
ANTON STEHLE.
By Huelser & Co.,
142, Fleet Street, London, Attorneys.