Improvements in Mills or Apparatus for Grinding or Crushing Hard Substances.
Year: 1895

page_text: Date of Application, 27th Dec., 1895
Complete Specification Left, 12th Aug., 1896-Accepted, 12th Sept., 1896
PROVISIONAL SPECIFICATION.
Improvements in Mills or Apparatus for Grinding or Crushing
Hard Substances.
We, HEINRICH CHRISTIAN MECKE of Uhlenhorst near Hamburg in the
German Empire, Managing Director of the following Company and the EISENWERK
(vorm. NAGEL & KAEMP) ACTIEN-GESELLSCHAFT, a company incorporated
according to the laws of the free City of Hamburg in the same place, do hereby
declare the nature of said invention to be as follows:-
:
For the purpose of grinding or crushing hard bodies, attempts have been made,
to employ grinding mills, wherein a number of rollers, by means of their shafts,
which shafts were extended upwardly through the lid of the grinding chamber,
were eccentrically suspended from the vertical grinding spindle in bearings
enabling them to swing, pendulum-like, in a plane determined by the axis of the
said spindle and the point of suspension. Grinding rollers arranged in this
manner however, when in operation, have a tendency of remaining behind their
point of suspension, so that their shafts form angles to the perpendicular, which
include this point, in planes practically tangential relatively to the circle of
revolution of the point of suspension. The consequence is that the two horizontal
suspension pivots of each roller, as their common axis is also tangentially directed
relatively to the said circle, are strained in an extremely unfavourable manner and
they are further overstrained owing to the fact that all the vibrations of each
roller occurring during the operation of the mill are transmitted to the pivots
except that small portion, which acts within the plane of oscillation of the grinding
rollers and in a tangential direction relatively to the circle of oscillation. Besides,
the want of yieldability of the rollers in the direction which is tangential to the
circle of the suspension point reacts upon the fineness of division of the material
ground, upon the expenditure of power necessitated by the operation of the mill
and upon the extent to which each grinding roller wears out, in a most objectionable
manner.
According to the present invention, these defects are remedied, firstly, by
substituting to the pair of tangential pivots a ball-and-socket joint, so that each
roller can swing in all directions, including tangential oscillation; and, secondly,
in order to avoid too great an amplitude of this tangential oscillation, by arranging
a driver on the grinding spindle preceding or following the roller shaft and
yieldingly connected with it by a loose sleeve or bearing on the shaft and an
elastic intermediate link, for instance a pressure-spring (when the shaft is pushed)
or a draw-spring (when the shaft is dragged).
The ball-and-socket joint, for the purposes of the present invention, is preferably
constructed in such a manner that, when the shaft of the roller revolves round its
axis, the said joint does not work and wear, the shaft being not immovably.
connected with the ball pivot, but the upper end of the shaft forming a gudgeon
by means of which the shaft rotates within the spherical pivot, so that the ball-
and-socket joint merely serves to allow the pendulum-like motion of the grinding
roller.
Dated the 27th December 1895.

page_text: Improvements in Mills or Apparatus for Grinding or Crushing
Hard Substances.
We, HEINRICH CHRISTIAN MECKE of Uhlenhorst near Hamburg in the
German Empire, Managing Director of the following Company and the EISENWERK
(vorm. NAGEL & KAEMP) ACTIEN-GESELLSCHAFT, a company incorporated
according to the laws of the free City of Hamburg in the same place, 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 :-
For the purpose of grinding or crushing hard bodies, attempts have been
nade, to employ grinding mills, wherein a number of rollers, by means of their
shafts, which shafts were extended upwardly through the lid of the grinding
chamber, were eccentrically suspended from the vertical grinding spindle in
bearings enabling them to swing, pendulum-like, in a plane determined by the axis
of the said spindle and the point of suspension. Grinding rollers arranged in this
manner however, when in operation, have a tendency of remaining behind their
point of suspension, so that their shafts form angles to the perpendicular, which
include this point, in planes practically tangential relatively to the circle of
revolution of the point of suspension. The consequence is that the two horizontal
suspension pivots of each roller, as their common axis is also tangentially directed
relatively to the said circle, are strained in an extremely unfavourable manner and
they are further overstrained owing to the fact that all the vibrations of each
roller occurring during the operation of the mill are transmitted to the pivots
except that small portion, which acts within the plane of oscillation of the grinding
rollers and in a tangential direction relatively to the circle of oscillation. Besides,
the want of yieldability of the rollers in the direction which is tangential to the
circle of the suspension point reacts upon the fineness of division of the material
ground, upon the expenditure of power necessitated by the operation of the mill
and upon the extent to which each grinding roller wears out, in a most objectionable
manner.
According to the present invention, these defects are remedied, firstly, by
substituting to the pair of tangential pivots a ball-and-socket joint, so that each
roller can swing in all directions, including tangential oscillation; and, secondly, in
order to avoid too great an amplitude of this tangential oscillation, by arranging
a driver on the grinding spindle preceding or following the roller shaft and
yieldingly connected with it by a loose sleeve or hearing on the shaft and an elastic
intermediate link, for instance a pressure-spring (when the shaft is pushed) or a
draw-spring (when the shaft is dragged).
The ball-and-socket joint, for the purposes of the present invention, is preferably
constructed in such a manner that, when the shaft of the roller revolves round its
axis, the said joint does not work and wear, the shaft being not immovably
connected with the ball pivot, but the upper end of the shaft forming a gudgeon by
means of which the shaft rotates within the spherical pivot, so that the ball-and-
socket joint merely serves to allow the pendulum-like motion of the grinding
roller.
One form in which this invention may be carried out is shewn by way of
example, in the two views given on the accompanying sheet of drawings, which
are, the upper one a vertical section, and the lower one a plan of the improved
grinding mill arrangement.
a is the grinding chamber, wherein is situated the grinding ring b upon which
two, or more, grinding rollers c are adapted to travel in a circular path receiving
a rotation around their axes from the ring 6 by friction. The shafts d, rigidly

page_text: connected with the said rollers, are extended upwardly and, about in the midst,
are carried through loose bearings e; while their upper ends, constructed to form
gudgeons fare fitted in bearings g. The bearings are outwardly ball-shaped and
rest in spherical or cup-shaped sockets or bearings h provided in the cross piece or
frame i, which is mounted upon the central spindle of the grinding mill. The
step bearing k of the grinding spindle is so arranged as to afford ready access
thereto. Above it the driver is secured to the spindle. The elastic or yielding
connection between the loose bearing e and the driver is formed by a spring m,
dragging the shaft d when the spindle rotates in the direction which is indicated
on the plan by an arrow. Stirring arms, blades, or wings n, arranged underneath
the rollers, move, or sweep, the material to be ground between the grinding path b
and the rollers c where it is crushed and ground to the condition of flour or powder.
Above the annular path, a sieve, or sifting frame, o is arranged, which retains the
coarser particles of the ground material, while allowing the finer particles to pass
through its meshes; whereupon these are discharged from the machine. Propelling
blades p are provided to drive, or throw, the ground material towards the sifting
frame. Above the sifting frame o the grinding chamber is closed in by means of
a casing 9. This mill be used for both dry or wet material.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is: :-
1. A pendulum mill for grinding or crushing hard substances provided with two
or more rollers, fast upon their shafts and, by means of such shafts, suspended
above the grinding chamber, eccentrically to the vertical grinding spindle; the
main feature of the mill being that-with a view to render the rollers yielding or
moveable in all directions, including that, which is tangential relatively to the
circle of revolution of the point of suspension-the rollers, or their shafts, are
suspended by means of ball-and-socket joints, such as g, h, while the requisite
limitation of the pendulum-like movements of the rollers, in about tangential
direction, is provided for by means of a driver, such as l, secured upon the grinding
spindle and pushing or dragging the shafts of the grinding rollers which may be
connected with this driver through the medium of loose bearings, such as e, and
yielding intermediate links, such as m, essentially as described.
2. A modified form of the pendulum mill referred to in the first claim, wherein
the hall-and-socket joint only serves the purpose of allowing the grinding
rollers to swing in all directions, while within the spherical pivot constructed as
at 9, the shaft of each grinding roller is made to revolve by means of a gudgeon,
such as f, essentially as described.
Dated this 12th day of Auơust 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.