Improvements in Pulleys.
Year: 1895

page_text: Date of Application, 6th Aug., 1895-Accepted, 12th Oct., 1895
COMPLETE SPECIFICATION.
[Communicated from abroad by DARIUS EPHRAIM NEWELL. of 421 West
23rd Street, New York, in the State of New York, United States of America,
Merchant.
Improvements in Pulleys.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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:-
As a
My invention is directed toward the overcoming of difficulties and inconveniences
which arise during the running of ordinary belts upon ordinary pulleys, namely,
the so-called air cushion or layer of air, which is drawn in between the surface of
the pulley and the inner surface of the belt as the two approach each other.
result of this air cushion, the belt does not have that adhesion to the surface of the
pulley which it is essential it should have to exert its proper effect in rotating the
pulley, and slipping oftentimes ensnes. Especially is this slipping action liable to
occur in belts having high linear velocity.
To obviate this defect, I provide pulleys having recesses or cavities designed to
prevent the formation of this air cushion or which offers a vent to such layers of
air when formed.
I will describe a pulley in which the features of my improvement are
embodied.
In the accompanying drawing,
Figure 1 is a front view of a pulley embodying my improvement. Figure 2 is a
section thereof.
Figure 3 is a front view of a pulley of modified form embodying my improve-
ment.
Similar letters of reference designate corresponding parts in all the figures.
My improvement is applicable to all forms and material of pulleys, including
wooden pulleys, cast pulleys or those which are of a built up construction, and
has reference solely to the manner in which the outer surface or periphery is
formed.
A designates a pulley whose outer surface is provided with a number of slots or
recesses a. Any suitable number may be used. B is the shaft to which the pulley
may be secured. These slots a may be of any convenient depth, and may pass
through the periphery of the pulley midway of their length, as shown in Figs. 1
and 2. the areas of these holes or openings at their inner surfaces being less than
the area of the recesses or pockets at the outer surface of the pulley. They may
be formed on the surface of the pulley by a milling machine, but if the pulley is
cast, the slots may be formed in the pulley at the time of molding the same.
They may, however, not extend through the periphery of the pulley, as shown
in Fig. 3, but consist of recesses or pockets therein. Each slot tapers centrally;
that is, its depth at its central portion is greater than the depth near the ends of
the slot.
In positioning the slots over the surface of the pulley, I preferably employ the
arrangement shown in the figures. As there shown, cach slot is disposed with its
longitudinal dimension extending approximately at right angles to the shaft B,
while the several slots are arranged in groups across the periphery of the pulley.

page_text: The several slots in each group are also arranged in line with the spaces between
the slots in an adjacent group, presenting thus a staggered appearance.
Having now particularly described and ascertained the nature of my inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. A pulley having a rim provided with a number of centrally tapering recesses
or pockets positioned circumferentially and arranged in groups over its outer
surface, the edges of the recesses or pockets on all sides being formed within the
peripheral surface of the pulley, and the recesses or pockets being provided
midway with holes or openings at their bottoms extending through the inner
surface of the rim, the areas of these holes or openings at their inner surfaces
being less than the area of the recesses or pockets at the outer surface of the
pulley, and the recesses in the several groups being relatively staggered, substan-
tially as specified.
2. A pulley having a rim provided with a number of centrally tapering recesses
or pockets positioned circumferentially and arranged in groups over its outer
sui face, the edges of the recesses or pockets on all sides being formed within the
peripheral surface of the pulley, substantially as specified.
Dated this 6th day of August 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.