Improvements in Sheaves for Pulley Blocks.
Year: 1897

page_text: Improvements in Sheaves for Pulley Blocks.
I, DAVID MCLACHLAN, of Lanfine House, Corporation Road, Cardiff, in the
County of Glamorgan, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to an improved method of making sheaves, or pulley
blocks, as commonly used on ship board. The sheaves usually constructed, have.
a series of live rollers, running in a cage in the centre of the sheave. These.
rollers and their attached cage frequently give way, and get adrift, in consequence
of the number of small and complicated parts, employed.
In my invention, I reduce the number of parts to a large extent, and do away
entirely with the cage, allowing the rollers to run freely in a prepared channel.
made as hereinafter to be described. I firstly form a shell with Hanges both
internal and external, the internal flange supporting the rollers, and the external
Hange the wood portion of the pulley. I make another flange almost similar in
shape, which lies closely up against the one previously described, and between
which the rollers revolve. This pair of flanges is not rivetted together, but is
formed in such a way that a male, and female screw is formed upon them, so that
one Hange is screwed into the other by means of a suitable key, thus enclosing
the rollers in the centre portion and the wood portion of the sheave on the outer
periphery small projecting lugs are formed upon one of the flanges and recesses
are cut into the wood work, so as to prevent any movement taking place between
the wood and metal portions, the flanges being screwed together, holds the wood
part of the sheave, taut and firm, rendering the usual rivets entirely unnecessary.
The metal portion thus described, can be made of any suitable noncorrosible metal,
as may be found most convenient.
Instead of having a wood external portion of the sheave one of the metal flanges
might be extended so as to form the sheave itself, the screwed flange being re-
cessed flushed into the face of its companion.
These rollers can be made barrel shape if necessary the shell being bored out
of the same shape.
Dated his 16th day of Monoh 1807
PHILLIPS & LEIGH,
Agents for the Applicant.
Improvements in Sheaves for Pulley Blocks.
I, DAVID MCLACHLAN, of Lanfine House, Corporation Road, Cardiff, in the
County of Glamorgan, Engineer, do hereby declare the nature of my invention
[Price 8d.]

page_text: and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement;―
This invention relates to improvements in the construction of sheaves for pulley-
blocks such as commonly used on shipboard. Such sheaves as usually con-
structed have a series of live rollers running in a cage mounted in the centre of
the sheave. These rollers and cage frequently give way and get adrift in con-
sequence of the number of small and complicated parts employed.
In my present invention the number of parts employed is comparatively small,
and the cage is entirely dispensed with, the rollers being allowed to run freely
in a prepared channel tormed as hereinafter described.
Accordingly, I form a cylindrical shell with internal and external flanges at
both ends. The central holes formed by the internal walls of the circular tanges
serve for the reception of the pintle or axle on which the sheave turns. The
internal flange supports the loose rollers, and the external one the wooden portion
of the sheave or part extending from the said shell to the periphery of the sheave.
The said shell may be in one piece, but is preferably made in two parts screwing
one into the other in such manner that when so screwed the internal surface of
the annular cavity thus formed by them is quite flush; this is effected by providing
one of the parts with an external screw thread, and the other part with an internal
thread and also a shoulder or circular ledge just the width of the thickness of the
substance of the one part upon which the external thread has been cut.
A perforated diaphragm or plate fi is or may be interposed in the annular
cavity between the two halves of the shell to keep the rollers from contact with
each other.
The rollers, which may be of cylindrical, barrelled, spherical, or any other suit-
able form, are placed loosely around the pintle in the annular space formed by,
the internal surface of the shell so that on screwing the two parts of the shell
together the rollers are thereby enclosed or boxed up, but free to revolve both
upon their own axis and around the pintle, for which they thus form a free roller
bearing. When screwed quite home the external surface of the flanges of the
said shell or box is or may be quite flush with the face of the sheave.
To prevent any bodily movement of one half of the shell while the other half
is being screwed into it, small snugs or projections are provided on the one half
which fit into corresponding holes or recesses made in the sheave.
The flanges being screwed together hold the wood or body part of the sheave
taut and firm, rendering the usual rivets entirely unnecessary.
The box or shell may be made of any suitable non-corrosible metal or other
substance as may be found most convenient.
The substance of the sheave extending laterally from the shell to the periphery,
instead of being of wood as usual, may be of the same substance as the shell, and in
fact may be simply an extension of the outer flange of the shell.
In the accompanying drawings representing my invention:-
Figure 1 is a sectional elevation of a sheave made according to this invention.
Figure 2 is a cross-section through the sheave..
Figure 3 is a cross-section through a pulley or sheave formed entirely of metal.
Figures 4 and 5 are front and side elevation, respectively, of the perforated
plate E.
Figure 6 shews the arrangement when the rollers are barrel form.
a is one half or part of the cylindrical shell or box, and b is the other part;
c are the external flanges and d the internal flanges; e and c¹ are the screw-
threads by means of which one part of the shell is screwed in the other, and f is
the circular shoulder or ledge upon which the internal rim of a rests as shewn
in Figure 3; g is the internal central annular cavity between the two internal
flanges of the shell, h are the loose rollers and i is the pintle or axle of the sheave,
jare the snugs or projections which drop into corresponding recesses in the
sheave to keep the half shell a from turning round bodily while the other half b
is being screwed therein.

page_text: Any convenient key may be employed to effect the screwing together of the
two halves of the shell.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is:-
1. A sheave for a pulley-block, consisting of a wheel the nave or boss of which
is formed of two cylindrical rings each provided with a circular internal and ex-
ternal flange and adapted to screw or lock one into the other and form an internal
central annular cavity adapted to receive and retain loose rollers or balls which
form a bearing for the pintle, substantially as described and set forth.
2. A sheave for a pulley-block, constructed substantially as herein described
and illustrated.
Patch at both day of Decentver lost.
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant,