A New or Improved Method of Driving Rotary Sieves.
Year: 1892

page_text: Date of Application, 3rd June, 1892
Complete Specification Left, 3rd Mar., 1893-Accepted, 20th May, 1893
PROVISIONAL SPECIFICATION.
A New or Improved Method of Driving Rotary Sieves.
I, JOHN MCDONELL, of 21 Upper Cecil Street, Limerick, Ireland, Mechanical
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to a new or improved method of transmitting
rotary motion to a single sieve, or a series of sieves, whether the series be arranged
one over the other, or side by side, or in line following each other longitudinally, by
means presently described.
In order to facilitate description of the invention, we will first take for example
a series of sieves arranged vertically one over the other.
At the end of the frame in which the sieves are hung, a vertical shaft is
mounted provided with a suitable crank for each sieve in the series. To each
crank is connected a horizontal oscillating link by means of brasses and set screws
in such a way as to allow to its free end a universal movement, .r., a vertical and
lateral movement. The free end of the oscillating lever is connected to a pivot
device hereinafter described fixed in the centre of the sieve. To the centre of this
oscillating lever are attached the ends of suitable chains or rods, whose opposite
ends are coupled up to eye bolts forming fixtures, so that the chains, or rods lie in
a horizontal plane, and at right angles to the oscillating link. These eye bolts are
fitted with threads and nuts for the purpose of adjusting the tension of the chains
or rods, and also with suitable springs to compensate for the variations in the length
of the chains due to their movement out of direct line.
The device to which the free ends of the oscillating links are connected consists
of a disk provided with four radiating rods or bolts, the outer ends of which are
attached to clamps fixed at or near the corners of the sieves. This device serves
the double purpose of providing for the attachment of the oscillating links, and
also for communicating the motion to the corners of the sieve where of course the
frame is strongest.
The action of the apparatus thus described is briefly this: As the vertical
shaft revolves, the to and fro movement of sieve is effected directly by the crank
and link, while the lateral movement is effected through the chains acting as a
fulcrum for the oscillating link. The two movements combined produce the desired
rotary motion.
The principle of the arrangement may be thus described.
If the central point of a lever is so guided that it may only move in a
longitudinal straight line, and if one end of the lever is caused to travel round
a relatively small circle having its centre en said line, the other end of the lever
will describe approximately a corresponding circle.
For driving a series of sieves by means of a horizontal shaft, according to my
invention, the cranks are connected in the first instance by oscillating links to the
sieves in the manner already described. The cranks however are made sufficiently
long to allow the brasses to rove a distance more than equal to half the movement
of the sieve on either side of the central position.
To suitable lugs on the brasses are connected chains or rods having their free
ends attached to eye bolts, similar to those above described, and arranged so that
the chains will be in a vertical plane, and at an angle of 45 degrees with the shaft.
The action is thus: As the shaft revolves, the to and fro movement is effected
direct by the crank and link, while the brasses (with the end of oscillating link
attached) will be caused to move upwards and downwards as the crank travels from
its highest to its lowest position, and vice versa, and the brasses being controlled by
the chains will move in an oblique direction thereby imparting a side or lateral

page_text: movement to the sieves, which combined with the to and fro movement will produce
the required rotary motion.
Dated this 1st day of June 1892.
J. K. FAHIE & SON,
9, Westland Row, Dublin, Agents for Applicant.
COMPLETE SPECIFICATION.
A New or Improved Method of Driving Rotary Sieves.
I, JOHN MCDONELL, of 21 Upper Cecil Street, Limerick, Ireland, Mechanical
Engineer, 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 has reference to a new or improved method of transmitting
rotary motion to a single sieve, or a series of sieves-whether the series be arranged
one over the other, or side by side, or in line following each other longitudinally-
by means presently described.
In order to facilitate description of the invention, we will first take for example
a series of sieves arranged vertically one over the other, and driven by a vertical
shaft.
Fig. 1, of drawings annexed hereto represents one of these sieves with its
accompanying driving attachments.
a, a, is the sieve; b, is section of crank on the vertical shaft mounted in front of
the sieve. To this crank is connected a horizontal oscillating link e, by means of
brasses and set screws, and its free end is pivoted to the centre of the sieve by
pivot d.
Midway between both ends of this link a square recess e, is provided for the
reception of the heads of two radius rods. These radius rods enter the recess
through elongated slots, and are provided with heads y, g, between which and the
walls of the recess are mounted double convex washers h, h. The free ends of the
rods penetrate suitable brackets in the framework 2, 2, and are provided with india-
rubber washers 3, 3, flat solid washers 4, 4, double convex washers 5, 5, and jam
nuts 6, 6.
This arrangement or combination of india-rubber pads and double convex washers
admits of an oscillating movement to the radius rods, while the jam nuts provide
for adjusting their tension to the required extent.
The action of this driving gear is this:-
As the vertical shaft revolves, the to and fro movement of sieve is effected
directly by the crank and link, while the lateral movement is effected through the
radius rods acting as a fulcrum for the oscillating link. The two movements combined
produce the desired rotary motion.
The principle of the arrangemeent may be thus described :-If the central
point of a lever is so guided that it may only move in a longitudinal straight
line, and if one end of the lever is caused to travel round a relatively small circle
having its centre on said line, the other end of the lever will describe approximately
a corresponding circle.
In order to drive a single sieve or a series of sieves arranged side by side by
means of a horizontal shaft according to my invention, the oscillating links are
attached to the sieves by an ordinary universal joint, while the arrangement of
radius rods is exactly similar in every respect to that just described.
The lateral
motion in this case is obtained as follows:-The driving crank on the horizontal
shaft Fig. 2, is made sufficiently long to allow the link brasses k, to rove a distance
more than equal to half the movement of the sieve on either side of the central
position. To suitable lugs on these brasses are attached chains or rods 1, 1, having
their free cnds attached to. eye bolts 7, 7, forming fixtures and so arranged that

page_text: the chains or rods will be in a vertical plane, and at an angle of 45 degrees with
the shaft.
The action is thus:--As the shaft revolves, the to and fro movement is
effected direct by the crank and link, while the brasses (with the end of
oscillating link attached) will be caused to move upwards and downwards as the
crank travels from its highest to its lowest position, and vice, versa, and the brasses
being controlled by the chains will move in an oblique direction, thereby imparting
a side or lateral movement to the sieve, which combined with the to and fro
movement will produce the required rotary motion.
The eye bolts are provided with threads and nuts for the purpose of adjusting
the tension of the chains, and also with suitable flat springs 8, 8, to compensate
for the variations in the length of the chains due to their movement out of direct
line. Instead of chains and eye bolts, rods rigged similarly to the radius rods f, f,
may be used.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I would have it understood,
that what I claim is :-
First. In the operation of communicating motion to rotary sieves, the use and
application of an oscillating link c, and radius rods ff, in combination with the
crank of vertical or horizontal driving shafts, arranged and operating substantially
as herein described and set forth.
Second. In driving rotary sieves, the arrangement of india-rubber washers, and
parallel flat, and convex washers for the purpose of enabling the radius rods to
oscillate to a certain extent, in the manner substantially as specified.
Dated 2nd day of March 1893.
J. K. FAHIE & SON,
9, Westland Row, Dublin, Agents for Applicant.