IMPROVEMENTS IN ROLLER MILLS
Year: 1880

page_text: LETTERS PATENT to Carl Pieper, Civil Engineer and Patent Agent, of
109-110, Gneisenau Strasse, Berlin, S.W., Prussia, for an Invention of
"IMPROVEMENTS IN ROLLER MILLS." A communication from Moritz Martin,
Engineer, of Bitterfeld, Prussia.
PROVISIONAL SPECIFICATION left by the said Carl Pieper at the Office of
the Commissioners of Patents on the 30th June 1880.
CARL PIEPER, Civil Engineer and Patent Agent, of 109-110, Gneisenau Strasse,
Berlin, S.W., Prussia. "IMPROVEMENTS IN ROLLER-MILLS." A communication
from Moritz Martin, Engineer, of Bitterfeld, Prussia.
This Invention relates to a roller-mill in which the two rollers are pressed against
each other by springs, and which is provided with special arrangements serving
for the purpose of regulating the space between the rollers and of equalising the
pressure of the springs on the four bearings of the rollers.
The machine is provided on either side with one or two wedge-shaped pieces (or
simply wedges) sliding in vertical guides, and which can be pressed downward
between the bearings of the rollers by means of screws. These screws are operated
upon by two worm-wheel gearings, whose worms are keyed on one shaft. The
rotation of the said shaft thus causes the wedges to be shifted downward or to rise,
whereby the space between the rollers is regulated. The pressure of the main
springs on the roller-bearings is maintained equal in the following manner :-
On each of the said wedges, of which there are by preference two on either side
of the machine, a spring (to be called regulating-spring) presses from above.
Moreover each wedge acts on one arm of a lever, catching with its other arm, and
in common with the corresponding arms of the other levers, into a sliding bar
suitably guided in the centre of the machine, so that any motion imparted by a
regulating spring to one wedge is transferred to all the other wedges. In case the
pressure of one of the main springs should by accident become less at, for instance,
the front end, and if in consequence the corresponding roller-end should yield more
during the grinding operation than the rear end, the wedge opposite to the weaker
or front part of the main spring being relieved of counter-pressure will be
forced downward by its regulating spring, but it will at the same time cause all
the other wedges to be shifted in the same manner, whereby the pressure of the
two rollers against each other at both ends is equalised again.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Carl Pieper in the Great Seal Patent Office on the 29th December
1880.
CARL PIEPER, Civil Engineer and Patent Agent, of 109-110, Gneisenaustrasse,
Berlin, S.W., Prussia. "IMPROVEMENTS IN ROLLER-MILLS." A communication
from Moritz Martin, Engineer, of Bitterfeld, Prussia.
This Invention relates to a roller-mill in which the two rollers are pressed against
each other by springs, and which is provided with special arrangements serving for
the purpose of regulating the space between the rollers, and of equalising the
pressure of the springs on the four bearings of the rollers.
The machine is provided on either side with one or two wedge-shaped pieces (or
simply wedges) sliding in vertical guides, and which can be pressed downward
between the bearings of the rollers by means of screws.
These screws are
operated upon by two worm-wheel gearings, whose worms are keyed on one shaft.
The rotation of the said shaft thus causes the wedges to be shifted downward or
to rise, whereby the space between the rollers is regulated.
The pressure of the main springs on the roller-bearings is maintained equal in
the following manner :-
On each of the said wedges, of which there are by preference two on either side
of the machine, a spring (to be called regulating-spring) presses from above.
Moreover, each wedge acts on one arm of a lever, catching with its other arm, and
in common with the corresponding arms of the other levers, into a sliding bar
suitably guided in the centre of the machine, so that any motion imparted by a
regulating spring to one wedge is transferred to all the other wedges. In case the
pressure of one of the main springs should by accident become less at, for instance,
the front end, and if in consequence the corresponding roller-end should yield more
during the grinding operation than the rear end, the wedge opposite to the weaker
or front part of the main spring being relieved of counter-pressure will be forced
downward by its regulating spring, but it will at the same time cause all the other
wedges to be shifted in the same manner, whereby the pressure of the two rollers
against each other at both ends is equalised again.
The improved machine is represented on the annexed two Sheets of Drawings.
Fig. 1 shows an end-view partly in section, the hopper being removed; Fig. 2 is a
longitudinal vertical section; Fig. 3, a section of the hopper with adjacent parts;
Fig. 4, a part of the plan; while the Figures 5 to 7 represent the new parts on a
larger scale.
The rollers a, a, made of chilled cast-iron, porcelain, or other suitable material,
revolve by their journals b, b, in bearings m, m, which are either capable of sliding
in horizontal guides formed by the frame of the machine, or which are made
movable in any other suitable manner; d, d, are springs composed in the style of
carriage-springs of a series of steel blades, and pressing on the said bearings. The
tension of these springs, and consequently the pressure of the rollers against each
other, can be regulated by the screws e,' e.
The arrangement serving to adjust the interval between the rollers, and which
constitutes the first part of this Invention, is as follows:-
Against an incline on the bearings m, m, the pieces k, k¹, k², and k³, act by their
inclined faces x, x, (see Figs. 1 and 5). Each of these pieces consists of two plates
of equal shape united by a bridge or guide-block i, the latter serving to guide the
said piece k, k¹, &c., between one of the cheeks c, c, of the frame and the center rib
of the crossbeam t, as may be seen to best advantage from the Figures 5 and 7, the
latter representing the said beam t with parts relating to the same in a view from
below. On each of the bridges i presses from above a pin g, the two pins on either

page_text: side of the machine being fixed in a plate operated upon by a screw p; whose
nut forms a worm-wheel gearing with a worm 8. The two worms 8 (one on
either side) being keyed on 'one shaft s', 'all the pieces k, &c., will be pressed
downward uniformly when the hand-wheel y is turned in the proper sense.
In consequence of such lowering of the said pieces these will act by their inclined
faces x, x, as wedges against the bearings m, and press the rollers apart from each
other equally at both ends. During their operation the pieces k, &c., bear with
their back against the projections n on the frame of the machine. The screws p, p,
being drawn back the springs d, d, cause the rollers to approach each other again,
while the bearings m, m, press the wedge-pieces k, k¹, k³, k³, upward.
The interval between the rollers can thus be regulated with great nicety, and
in case the rollers are adjusted very close to each other, the described arrangement
prevents one roller striking against the other, if any foreign body, such as a
stone, should happen to fall between the rollers, and to force them apart during
its passage.
The second part of my Invention consists in arrangements for maintaining equal
the pressure of the springs d on the four bearings of the rollers, even when the
tension of either spring should become less at one end from some accidental cause.
For this purpose the following combination has been adopted:
Between the wedges k, &c., and the ends of the beam t, the springs ƒ, ƒ¹‚ ƒ³, ƒ³,
(regulating springs), which may be of spiral or other suitable shape, are inserted.
Each of these springs tends to press downward, and against the force of the spring d,
the wedge k, k¹, k², or k³, on which it acts. Any motion actually imparted to one
of the wedges, for instance k, is however transferred to the parts k¹, k², and k³, in
the following manner :-h, h', h³, and h, are four levers of equal size pivoted at
their centre to the cross-beam t, and penetrating with one end into a recess in the
corresponding part k, whereas their other ends enter together into a hole at the
lower end of the sliding-bar w, which is guided in a hollow boss in the centre of
the beam t. It follows from this arrangement that when one wedge-piece is shifted
the other corresponding parts will be displaced in the same manner.
Supposing now the pressure of one of the springs d to become less at one end
from any cause whatever, such as, for instance, a want of uniformity of the metal
out of which it is made, the end of the roller on which the weaker part of the
spring acts cannot compress to the saine extent the substances to be crushed, and
will therefore recede further from the cooperating roller than the end acted upon
with the full force by the other spring part. But as soon as this occurs the wedge-
piece corresponding with the roller-end which recedes further, for instance the
piece k, will be pushed downward by its regulating-spring f, whereby the end of
the lever h engaging with k is also made to descend, while its other end catching,
together with the corresponding ends of the levers h¹, h2, and h³, into the sliding-
bar w, causes this bar to rise, and the levers h1, h2, h3, to be shifted in the same
manner as h. The part of the force of the spring f which had become free by the
decrease of the resistance acting against it, is thus caused to assist the other
springs f, f, f³, in overcoming the stronger counter-pressure of the springs d to
which they are exposed until a balancing of the forces has taken place at the four
points, and the pressures against the bearings of the rollers have become equal.
The wear of the surface of the rollers is thereby rendered uniform upon their
whole length.
As a point of secondary importance, not constituting an essential part of this
Invention, may yet be mentioned the ductors q. These are pivoted by their
levers to arms fixed to the bearings m, so that they will be shifted together with
the rollers, and that they consequently always act upon them in the same manner.
Each ductor consists of two blades, of which one is pressed against the roller by
the weight at the end of the lever, while the other blade is caused to operate by
means of a spring attached to the first blade. .
The material to be ground is fed in between the rollers from a hopper u by
means of a feed-roller u¹, which is put in rotation in any suitable manner. The

page_text: rollers are by preference both provided with a pulley, so that they may each be
driven by a separate strap.
With regard to modifications of the described machine it is to be observed that
the wedge-pieces on either side of the same may be united in one if preferred.
Thus k and k¹ on one hand, and k³ and k³ on the other, may form one piece, and
each of these combined parts need be provided but with a single spring f and a
single lever h, while the pins g, g, are replaced by an elongation of the screw p.
Having thus described the nature and object of this Invention, and the manner
in which it is to be carried out in practice, as communicated to me by my
correspondent, I claim as new and important features of the same,-
1. The combination with the rollers a rotating in movable bearings m, and
provided with springs d, of a mechanism consisting of the wedge-pieces k, k³, k³, k³,
which may be united in pairs, these pieces acting on the bearings m while they are
simultaneously operated upon by the screws p, actuated by two worm-wheel
gearings, substantially as and for the purpose described. .
2. The combination with the rollers a, movable bearings m, springs d, and wedge-
pieces k, k¹, k, k³, which may be united in pairs, of two or four regulating springs
ffff, and two or four levers h, h', h³, h³, operating together in the manner
herein before described.
In witness whereof, I, the said Carl Pieper, have hereunto set my hand and
seal, this Fourteenth day of December, in the year of our Lord One thousand
eight hundred and eighty.
CARL PIEPER. (LS.)