IMPROVEMENTS IN FRICTION COUPLINGS
Year: 1876

page_text: LETTERS PATENT to James Duncan, of Mincing Lanc, in the City of London,
for the Invention of "IMPROVEMENTS IN FRICTION COUPLINGS." A com-
munication from abroad by Albert Fesca, of Berlin, in the Empire of Germany
Sealed the 28th July 1876, and dated the 30th May 1876.
PROVISIONAL SPECIFICATION left by the said James Duncan at the Office
of the Commissioners of Patents on the 30th May 1876.
"IMPROVEMENTS IN
JAMES DUNCAN, of Mincing Lane, in the City of London.
FRICTION COUPLINGS." A communication from abroad by Albert Fesca, of Berlin,
in the Empire of Germany.
This Invention relates to friction couplings intended more particularly for use in
transmitting motion to centrifugal machines employed in the manufacture of sugar,
but is equally applicable in all cases where friction couplings are advantageous, and
it has for its object imparting to the machine a gradually accelerating speed in
order to prevent undue strain upon the driving straps when starting the machine.
In carrying out this Invention, as applied, for example, to a centrifugal machine,
the fast and loose driving pulleys, which receive motion from the steam engine or
other prime movor, are mounted upon a sleeve fitted to rotate upon a countershaft,
having keyed thereon a hollow drum or pulley, over which passes a strap for trans-
mitting motion to the machine. The fast driving pulley, which is, nevertheless, not
keyed on the shaft, is formed with an elongated cylindrical boss, which enters the
interior of the hollow drum keyed to the countershaft, and is surrounded by two
friction straps, connected by their ends to lugs formed on diametrically opposite
sides of the interior of the hollow drum. These friction straps are each provided
with springs, the tension of which is regulated by means of a screw and set nuts
for the purpose of adjusting the amount of friction required to be imparted to the
elongated boss of the fast driving pulley in order to prevent it from rotating on the
countershaft.
Upon starting the machine by shifting the driving belt from the loose pulley on
to the fast pulley, the latter, and the sleeve which carries it, will rotate at full speed
upon the countershaft, and the elongated boss rotating within the friction straps
will by its frictional contact therewith impart motion to the hollow drum to which
they are attached. At the commencement only a portion of the speed of the

page_text: driving pulley will be imparted to the drum, the boss partially rotating within the
straps, but after a short time the speed of the drum will be accelerated by reason of
the frictional contact of the straps, and will acquire the same speed as that of the
driving pulley, the fast pulley being prevented from rotating upon the countershaft
by the grip the frictional straps have upon its clongated boss. A hole is provided 5
in the elongated boss of the fast pulley for the introduction of lubricating material,
which enters between the sleeve and the shaft upon which it is mounted, which hole
is closed by means of a screw plug.
It is also necessary for the proper working of the coupling to maintain the long
boss in a perfectly lubricated condition by introducing the lubricating material 1
between the said boss and the friction straps.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said James Duncan in the Great Seal Patent Office on the 30th November
1876.
JAMES DUNCAN, of Mincing Lane, in the City of London. "IMPROVEMENTS IN
FRICTION COUPLINGS." A communication from abroad by Albert Fisca, of Berlin,
in the Empire of Germany.
The said Invention relates to friction couplings intended more particularly for use
in transmitting motion to centrifugal machines employed in the manufacture of sugar,
but is equally applicable in all cases where friction couplings are advantageous, and
it has for its object imparting to the machine a gradually accelerating speed in
order to prevent undue strain upon the driving straps when starting the machine.
And in order that the said Invention may be fully understood, I shall now pro-
cecd more particularly to describe the same, and for that purpose shall refer to the
several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in both the Figures.
Figure 1 of the accompanying Drawing represents a longitudinal sectional eleva-
tion of a coupling, constructed according to this Invention; and Figure 2 is a
tranverse soctional elevation of the same.
In carrying out this Invention, as applied to a centrifugal machine, for example, the
fast and loose pulleys A, A', which receive motion from a steam engine or other
prime mover, are mounted upon a countershaft B, having keyed thereon a hollow
drum or pulley C, over which passes a strap for transmitting motion to the machine.
The fast or driving pulley A, which is, nevertheless, not keyed on the shaft, is
formed with an elongated cylindrical boss D, which enters the interior of the hollow
drum C, and is surrounded by two friction straps E, E, the ends of which are
secured in the following manner:-The ends F of the straps E, E, are connected to
two lugs G, G, formed on diametrically opposite sides of the interior of the hollow
drum C, whilst the opposite ends of such straps are attached to bolts H, H, which
pass through metal eye pieces I, I, carried by the lugs G, and are surrounded by
springs K, the tension of which is regulated by means of set nuts L, L, for the
purpose of adjusting the amount of friction required to be imparted to the elongated
boss D of the driving pulley, in order to prevent it from rotating on the counter-
shaft.
Upon starting the machine by shifting the driving belt from the loose pulley A¹
on to the driving pulley A, the latter will rotate at full speed upon the counter-
shaft B and the elongated boss D, rotating within the friction straps E, E, will by
its frictional contact therewith impart motion to the hollow drum Ċ to which they
are attached. This motion at the commencement will be very slow, a portion only
of the speed of the driving pulley being imparted to the drum in consequence of
the friction of the straps not being so great as to entirely prevent the boss from
rotating within the straps; the speed of the drum, however, will be gradually

page_text: accelerated by reason of the engagement by the frictional contact of the straps over-
coming its vis inertia, and it will ultimately acquire the same speed as the driving
pulley. A hole a is provided in the elongated boss of the driving pulley for the
introduction of lubricating material, which passes between the boss and the shaft,
the hole being closed after the lubricant has been introduced by means of a screwed
plug b.
It is also necessary for the proper working of the coupling to maintain the outer
surface of the long boss D in a perfectly lubricated condition by introducing
lubricating material between the said boss and the friction straps.
It is obvious that the drum C, as well as the pulley A, may be mounted loose
upon the shaft B, and a similar result be obtained.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or inay be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, imparting a gradually accelerating speed to machinery or apparatus
in starting the same by transmitting motion from the driving pulley to the
machinery or apparatus to be driven by means of a drum connected to such pulley
by adjustable friction straps, substantially as horein-before described and illustrated
by the accompanying Drawings.
In witness whereof, I, the said James Duncan have to this my Specification
set my hand and seal, this Twentieth day of October, One thousand eight
hundred and seventy-six.
JAMES DUNCAN. (L.S.)