IMPROVEMENTS IN THE CONSTRUCTION OF SHEAVES OR PULLEYS
Year: 1878

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake, &
Co., Patent Agents, Southampton Buildings, London, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF SHEAVES OR PULLEYS." A com-
munication from abroad by Herbert Loud, of Boston, Massachusetts, United
States of America.
Sealed the 17th January 1879, and dated the 18th November 1878.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 18th November 1878.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE CONSTRUCTION OF
SHEAVES OR PULLEYS." [A communication from abroad by Herbert Loud, of
Boston, Massachusetts, United States of America].
This Invention relates to the construction of sheaves or pulleys of metal and
wood combined as herein-after described.
The said improved sheaves or pulleys have a body made of cast-iron with an
annular recess in each of its sides. Into each recess is tightly driven a corre-
sponding annular block or piece of lignum-vitæ, and each of these wooden blocks
is greater in thickness than the depth of its recess, and each of the said blocks
projects slightly beyond the sides of the body.
The metal body at its centre is bored to receive the axial pin of the block, and
its edge or periphery is covered with brass cast thereon and grooved for the
rope.
A sheave or pulley made as above described, that is to say, of a cast metal body
with lignum-vitæ blocks let into its sides, combines in itself all the advantages
belonging to a sheave or pulley made simply of cast-iron, while at the same time
it is lighter than such a sheave; moreover it combines all the advantages belonging
to a sheave made simply of lignum-vitæ, while at the same time it is stronger
Prino 71

page_text: stiffer, and more rigid than such a sheave; and furthermore by the union of
all the advantages of a cast-iron sheave and of a lignum-vitæ sheave in one
and the same sheave the disadvantages of each are obviated, and as the lignum-
vitæ projects at each side of the sheave the rim of the sheave is kept from contact
with the cheeks of the block; this construction prevents the wear of the cheeks and
the sharpening of the edges of the rim, which sharpening if it occurred would be
apt to cut the rope running on the rim.
It is obvious that other metals may be substituted for the cast-iron, but cast iron
is preferable as it is sufficiently durable and yet cheap, and other wood may be sub-
stituted for the lignum-vitæ, but lignum-vitæ is preferable.
The brass covering for the periphery of the sheave affords a smoother and better
running-surface for the ropes than the cast-iron would give, and it is advantageous to
combine it with the cast-iron body as described, but this covering may be dispensed
with, or other metals may be substituted for brass. Or the sheave body may be made
entirely of brass or other metal that would present a similar running-surface on the
sheave for the rope; but as brass and such other metals are costly compared with
cast-iron, and as cheapness in the sheave is desirable if it can be obtained con-
sistently with other requisites, it is preferable to use cast-iron, obtaining the other
desirable features for the sheave by applying or attaching to such a body such other
materials as will secure them, as for instance, lignum-vita and brass, as above
described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the 16th
May 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE CONSTRUCTION OF
SHEAVES OR PULLEYS." A communication from abroad by Herbert Loud, of
Boston, Massachusetts, United States of America.
This Invention relates to the construction of sheaves or pulleys of metal and
wood combined as hereinafter described, and as illustrated in the accompanying
Drawing in which,
Figure 1 is a side view, and
Figure 2, a cross-section of a sheave or pulley constructed according to this
Invention.
Figure 3 is an edge view of the sheave in its block, drawn to a reduced scale.
A represents my improved sheave or pulley; B is its body, made of cast-iron
with an annular recess C in each of its sides D. Into each recess C is tightly
driven a corresponding annular block or piece E of lignum-vitæ, and each of these
wooden blocks is greater in thickness than the depth of its recess C, and each of the
said blocks projects beyond the sides D of the body B as shown at a, a.
The metal body B at its centre b is bored to receive the axial pin of the block,
and its edge or periphery G is covered with brass H. cast thereon and grooved as
at c for the rope.
A sheave or pulley made as above described, that is to say, of a cast metal body
with lignum-vitæ blocks let into its sides, combines in itself all the advantages
belonging to a sheave or pulley made simply of cast-iron, while at the same time
it is lighter than such a sheave; moreover it combines all the advantages belonging
to a sheave made simply of lignum-vitæ, while at the same time it is stronger,
stiffer, and more rigid than such a sheave; and furthermore by the union of all the
advantages of a cast-iron sheave and of a lignum-vitæ sheave in one and the same
sheave the disadvantages of each are obviated, and as the lignum-vitæ projects at
each side of the sheave the rim of the sheave is kept from contact with the cheeks
of the block, thus preventing the wear of the checks and the sharpening of the
edges of the rim, which sharpening if it occurred would probably cut the rope
running on the rim.
It is obvious that other metals may be substituted for cast-iron, but cast-iron is
preferable as it is sufficiently durable and yet cheap, and other wood may be sub-
stituted for the lignum-vitæ, but lignum-vitæ is preferable for reasons
known.
well
The brass covering H for the periphery of the sheave affords a smoother and
better running surface for the ropes than the cast-iron would give, and it is
advantageous to combine it with the cast-iron body as described, but this covering
may be dispensed with or other metals substituted for brass. Or the sheave body
B may be made entirely of brass or other metal that will present a similar running-
surface on the sheave for the rope, but as brass and such other metals are costly
compared with cast-iron, and as cheapness in the sheave is desirable if it can be
obtained consistently with other requisites, it is preferable to use cast iron and to
obtain the other desirable features for the sheave by applying or attaching to its
body such other materials as will secure them, as, for instance, lignum-vitæ and
brass as above described.
The checking or splitting of the lignum-vitæ, if not wholly, is practically pre-
vented by its confinement in the sides of the metal body of the sheave.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I do not limit myself to any particular thickness of the wood-blocks or to the

page_text: precise manner of attaching the wood and the brass or other covering to the iron
body, and I claim-
First. A sheave or pulley with a metal body and wooden blocks or cheeks
inserted or inlaid in recesses in its sides, substantially as and for the purpose set
forth.
Second. A sheave or pulley with a metal body and an attached metal rim, sub-
stantially as described and for the purpose specified.
Third. A sheave or pulley with a metal body and an attached metal rim and
provided with wooden blocks, substantially as described and for the purposes set
forth.
Fourth. A sheave or pulley with a metal body fitted with wooden blocks and
either with or without the metal rim and in which the wood projects at the sides
of the sheaves, as and for the purpose specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Sixteenth day of May, in the year of our Lord One
thousand eight hundred and seventy-nine.