An Improved Pulley with Adjustable Diameter.
Year: 1896

page_text: Date of Application, 11th Nov., 1896-Accepted, 23rd Jan., 1897
COMPLETE SPECIFICATION.
An Improved Pulley with Adjustable Diameter.
I, PAUL RICHARD SCHUBERT, Engineer of Chemnitz Saxony in the Empire
of Germany, do hereby declare the nature of my invention and in what manner
the same is to be performed to be particularly described and ascertained in
and by the following statement :-
The present invention consists of an improved sheave pulley with adjustable
diameter.
In order to render the present specification more easily intelligible reference is
had to the accompanying drawing in which similar letters of reference denote
similar parts throughout the several views :-
Fig. 1 is an end elevation of a pulley constructed according to the present
invention having the rim cut away,
Fig. 2 is a side elevation of the pulley adjusted to the smallest diameter and
Fig. 3 a similar elevation with the pulley adjusted to the largest diameter.
The pulley represented in the drawing consists of a disc a having a projecting
boss a fixed to the shaft by means of set screws a 2 or the like, which are
advantageously covered by a casing a 3. In this disc a are arranged dovetail
grooves running radially and adapted to form guides for the sliding spokes b
which support the rim g of the pulley. The spokes b are provided with
projecting pins c which engage in curved slots d' of a disc d mounted to turn on
the shaft on which the disc a is supported. The rim 9 is advantageously
provided with downwardly extending edges which grip round the upper ends of
the sliding spokes b and one end of the said rim is made fast to one of the spokes,
the opposite end being guided by means of a pin g' in a slot of the said rim.
The disc d is provided at one part of its rim with teeth d 2 in which a pawl e
pivoted to the disc a engages said pawl being held in engagement by means of
spring f. The boss of the disc d is square or hexagonal so that the said disc
may be turned on the shaft by means of a spanner. The spokes, with the
exception of the one attached to the rim slide in the groove formed by the
latter.
The operation of the device takes place in the following manner :-
If it is required to enlarge the diameter of the pulley, the disc d is turned on
the shaft and forces the spokes outwardly by means of the slots d' acting on
the pins c of the spokes, during this movement the pawl e slides over the teeth d 2
of the disc and falls into the same as soon as the required diameter has been
attained. The disc d may further be retained in position by means of a nut c¹
on one of the pins c which may be clamped to the said disc. The pin carrying
the clamping nut is advantageously covered by a cap c 2. The ends of the spokes
which are actuated outwards by this movement of the disc d slide in the rim 9 the
end of which is guided by the pin g' in the slot in the said rim.
The rim as also all the discs may be made in two parts if desired as will be
obvious.
In the case of rope pulleys, the rim may be grooved, or in some cases the rim
may be dispensed with and the rope guided on the ends of the spokes.
When it is required to reduce the diameter of the pulley, the pawl e is lifted out
and the disc d turned in the opposite direction, the rim g being pressed on to the
spokes as they are reduced in length. The rim will probably follow the motion

page_text: of the spokes as it is of steel and adapted to clasp round the said spokes. When
the disc has been sufficiently reduced in diameter the nut c may be tightened up
and the pawl allowed to fall into engagement with the teeth of the disc d.
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 :-
A sheave or rope pulley having an adjustable diameter, characterised by a
revoluble disc d adapted by means of curved slots and pins guided therein to
actuate several radially guided spokes by means of which the circumference of
a smooth rim or a rim provided with edges overlapping the ends of the spokes
may be increased or reduced the ends of said rim overlapping, and being retained
in any desired position by means of a spring pawl or clamping mechanism sub-
stantially as described.
Dated this 11th day of November 1896
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.