Improvements in Weston's Centrifugal Machines.
Year: 1891

page_text: Date of Application, 9th Apr., 1891-Accepted, 9th May, 1891
COMPLETE SPECIFICATION (AMENDED).
Improvements in Weston's Centrifugal Machines.
I, JOHN LAIDLAW, of the firm of Watson Laidlaw & Co. of 98 Dundas Street,.
Kingston, Glasgow, North Britain, Engineers, 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:—
My invention relates to improvements in that class of centrifugal machines used>
in the manufacture of sugar which are suspended from above by elastic bearings
to allow of the basket revolving round the proper axis corresponding to the
distribution of materials in the basket. Centrifugal machines of this class are
well known and have been in use for many years, and known as the Weston
centrifugal. The present invention relates more particularly to improvements in
details to render the machine more convenient to operate and to increase its
efficiency.
In order that my invention may be properly understood and readily carried into
effect I have hereunto appended three explanatory sheets of drawings in the
several figures of which corresponding parts are marked with the same letters of.
reference.
Figure 1 is an elevation; and Figure 2 a plan of the machine.
Figure 3 is a cross section at a b, Figure 2.
-Figure 4 is a part section of one half of the driving wheel.
Figure 5 is a part vertical section at c d, Figure 1.
Figure 6 is an enlarged section of the elastic support for suspending the machine,
and driving pulley.
The frames e, e are made of a suitable section as shown at Figure 3, so that
between the two frames e, e of each centrifugal and underneath the driving belt a
number of boards or laths of wood f, f, or other material may be placed, and
bolted to the frames e, e as shown at Figure 3, to form a protection, so that the
attendant can work the machine when he is underneath the driving pulleys and
belts without danger.
The guide-pulley 9, Figure 2, for the driving belt, instead of being a loose
pulley on an arm from the frame is fixed on to the shaft which revolves in
ournals i, i on the framework of the machine.
The machine is driven by a belt from a centrifugal friction pulley, one half of
which is shown in enlarged section at Figure 4. K is the pulley proper which
carries the belt and rides loose on the shaft jj. L, Figure 4, is a double arm
bolted or keyed to the shaft at L₁, and revolving with it, which carries a toe-
ever pivoted at m. To this toe-lever an arm is attached, which is connected
o the friction shoe M, and likewise to the driving arm L by means of a steel
pring. The friction shoe M is faced with leather, and turned to the same
017
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page_text: curvature as the inside of the rim of the pulley. As the driving arm L revolves
with the shaft, it carries with it the toe-lever 1, the arm, and the friction shoe M,
with steel spring 13. The toc-lever being pivoted at m the friction shoe M is
free to fly outwards by centrifugal action and press against the rim of the
pulley K, and carry the latter round with it. As shown in Figure 4 this tendency
is resisted by the projecting wedge-shaped prongs X, X, cast in one piece with
the sliding sleeve t, but by moving the sleeve t a short distance along the shaft
by means of the hand lever, Figure 2, the friction shoe M is free to move out-
wards and transmit its motion to the pulley K. This form of centrifugal friction
pulley is well known, and the present improvement relates to means for adjusting
the arm to the proper length.. One end is screwed as shown at 7, and passes
through a slightly oval hole in 1, and two nuts 1, 15 are screwed on to the end
of . The inside of nut is made spherical to allow the necessary movement in
toe-lever . By altering the position of the nuts 1, 2, the position of the curved
friction shoe M may be adjusted relatively to the rim of the pulley K, so that it
may be suitably controlled by the travel of the toe-lever sliding upon the
wedges X X of the sleeve t, and the two nuts 1, lock each other to prevent the
length altering after adjustment.
The outer casing m is fixed to the frame of the machine by four bolts n, n², n³, n³,
Figure 5, so that, after detaching the machine from the overhead suspending
beam, when the upper two bolts n, n³ are removed, the outer case with the basket
may be turned round upon the other two, as shown in dotted lines at Figure 1,
to allow the basket to be removed for repairs and to be readily got at for
cleaning.
The elastic bearing for suspending the centrifugal spindle which carries the
basket, illustrated at Figure 6 is an improvement on that described in Weston's
Specification No. 2550, A.D. 1870. The improvement consists of making. the
india-rubber or other clastic pieces o, o of wedge-shaped cross-section with the"
smaller area near the spindle p, as shown on the drawing. This gives a more"
uniform pressure for different positions of the spindle.
The combined brake and driving pulley ry is constructed of larger diameter
and with parallel sides at the lower part, to give a greater surface for the brake to
act on; while the upper part for the belt is of smaller diameter. Thus a ledge or
flange is formed between the two parts, which acts as a guide to prevent the belt
from falling down and being destroyed by coming in contact with the brake strap.
This pulley is put on to the shaft from above. The hole in the centre is of
smaller diameter at the top, and is fixed firmly to this shaft by a feather r¹ below.
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 the Weston self-balancing suspended centrifugal machines which are driven"
by a pulley at the top, the providing of a guard between the frames and under-
neath the driving belt in the manner and for the purpose described.
2. In the Weston self-balancing suspended centrifugal machines, the guide
pulley for the belt fixed on to a shaft revolving in stationary journals carried by
the two side frames of the machine.
3. In the Weston self-balancing suspended centrifugal machines, the adjustable
arm for controlling the friction arrangement of the driving wheel, substantially as
described with reference to Figure 4.
4. In the Weston self-balancing suspended centrifugal machines, the method of
attaching the outer casing. to the framework by means of four bolts or their
equivalent, as and for the purpose described with reference to Figure 5.
5. In the Weston self balancing suspended centrifugal machines, the improved
shape of elastic bearing, substantially as described with reference to Figure 6.
65. In the Weston self-balancing suspended centrifugal machines, the combined
brake and driving pulley r q constructed of larger diameter and with parallel sides

page_text: at the lower part, and of smaller diameter at the upper part, and having a ledge
or flange between the two parts, substantially as described with reference to
Figure 6.
Dated this 8th day of April, 1891.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.