Improvements in and relating to Sheaves for Fishing or other Boats.
Year: 1889

page_text: Date of Application, 19th Nov., 1889
Complete Specification Left, 15th Sept., 1890-Accepted, 15th Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in and relating to Sheaves for Fishing or other
Boats.
I, WILLIAM LAWRENCE MITCHELL, Junior, of Abbotshall Foundry, Kirkcaldy,
Fifeshire, Engineer, do hereby declare the nature of my invention to be as
follows:-
This invention has reference to and comprises a new or improved construction or
arrangement and combination of the parts of hoisting or hauling pulley block sheaves
and their containing frames and fittings, specially adapted for the mastheads of fishing
or other boats for the hoisting of the main or lug sails, and such like purposes, in
which the pulley turns with the wire or other rope passing round it in the direction
of, and while hoisting the sail, but has a special ratchet arrangement by which it
cannot turn back with the lowering of the sail and slackening of the rope, which thus
has to slide over the pulley as a friction or brake action and so is not so severe on
the hoisting gear of the rope, and holds the sail firmer in its "taut" or hoisted position,
and which arrangement of sheaves and their fittings will be more durable and efficient
than such sheaves as heretofore constructed.
According to one construction of this improved stop sheave or pulley mechanism,
and its block or case, the pulley or sheave is made with a half round groove, and from
six to ten or twelve inches in diameter and of a width of from inch and half to two
inches, according to the size and strength of wire rope used to run in the groove of
the sheave. This sheave is made of a ring-like form, that is, with a large hollow bored
eye, which may either rotate on a large solid turned boss, on its case, or block, or
preferably on small antifriction rollers filling up an annular space between the turned
eye and boss, the rollers being nearly the depth of the eye of the pulley sheave to
rotate freely within it, and work with less friction, or lubrication than on the solid
boss. The case or block in which the pulley is mounted is preferably made of cast-
malleable iron or steel, and has the deep boss or eye on which the pulley turns cast on
the centre of one of its sides with square ends also cast on it projecting fully the depth
of the pulley when so mounted on the projecting central eye or boss, the portable or
removable side of the block or case being flat and checked into these ends, secured by
corner bolts passing through these ends to bolt the case together, and secure the sheave
between them as hereinafter described. The central boss has a bored part into which
a shallow projecting eye on the removable side of the case enters to keep all concentric
with the eye of the pulley, and a hole is cast or bored through the centre of these
retaining central bosses for a bolt to pass through, with sunk recesses for the head and
nut to retain and strengthen the sides at the centre.
A special improvement consists in forming the pulley or sheave with an inner
projecting flange on the one side of its eye next the side or cheek of the block on
which the deep eye is cast, and in forming this flange with ratchet teeth, into which
a vertical sliding pawl works through the bottom part of the eye, sliding up into the
recess formed for the head of the centre bolt, with a slot on its outer end working on
a collar part of the head of the bolt as a guide for the ratchet pawl, which works
radially up and down gliding over the teeth as the pulley is turned by the wire rope
in raising the lug sail; and when the hoisting is stopped the pawl falls into the nearest
ratchet tooth and holds the pulley from turning in the backward direction. The inner
sides of the case are formed with narrow projecting segments over the edges of the
pulley to guide the rope truly on to the groove and prevent it riding on its edges.
When the two parts of the case are put together with the pulley mounted within on
the projecting eye and antifriction rolls, and secured as described by the corner and
centre bolts, the whole is ready for inserting the rectangular case firmly within the

page_text: large slot or mortise formed for it in the head of the mast, to which it is secured by
two central end rivets or bolts passing through the case and mast. The wire rope
from the sail is passed over the pulley which turns and acts all as described when the
sail and wire rope is hoisted or lowered.
In the case mentioned where the sheave is mounted on the solid eye and lubricated
by oil, the ratchet teeth would preferably be cast or formed in the centre of the hollow
eye of the pulley; and the solid eye on the case would be made large and hollow, and
have the check formed in the centre of the solid boss for the radial pawl passing down
into these ratchet teeth, and rise and fall radially in gliding over the ratchet teeth on
the middle of the central securing bolt, instead of on the end of it as in the former
arrangement, as the pulley was turned in the hoisting direction, but fall and secure
the pulley from turning backwards when the hoisting ceased; otherwise this arrange-
ment would be of the same construction as the former.
Dated the 18th November 1880
COMPLETE SPECIFICATION.
Improvements in and relating to Sheaves for Fishing or other
Boats.
WILLIAM LAWRENCE MITCHELL Junior, of Abbotshall Foundry, Kirkcaldy Fife-
shire, Engineer 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 :-
This invention has reference to and comprises a new or improved construction or
arrangement and combination of the parts of hoisting or hauling pulley block sheaves
and their containing frames and fittings, specially adapted for the mastheads of fishing
or other boats for the hoisting of the main or lug sails, and such like purposes, in
which the pulley turns with the wire or other rope passing round it in the direction
of and while hoisting the sail, but has a special ratchet arrangement by which it cannot
turn back with the lowering of the sail and slackening of the rope, which thus has to
slide over the pulley as a friction or brake action and so is not so severe on the hoisting
gear of the rope, and holds the sail firmer in its "taut or hoisted position, and which
arrangement of sheaves and their fittings will be more durable and efficient than such
sheaves as heretofore constructed.
"
According to one construction of this improved stop sheave or pulley mechanism,
and its block or case. the pulley or sheave A is made with a half round groove, and
from six to ten or twelve inches in diameter and of a width of from inch and half to
two inches, according to the size and strength of wire rope used to run in the groove
of the sheave. This sheave is made of a ring-like form, that is, with a large hollow
bored eye, which may either rotate on a large solid turned boss B, on its case or block,
or preferably on small antifriction rollers R filling up an annular space between the
turned eye and boss, the rollers being nearly the depth of the eye of the pulley sheave
to rotate freely within it, and work with less friction, or lubrication than on the solid
boss. The case or block in which the pulley is mounted is preferably made of cast
malleable iron or steel, and has the deep boss or eye B on which the pulley turns cast
on the centre of one of its sides with square ends also cast on it projecting fully the
depth of the pulley when so mounted on the projecting central eye or boss B, the
portable or removable side of the block or case being flat and checked into these
ends secured by corner bolts passing through these ends to bolt the case together, and
secure the sheave between them as hereinafter described.
The central boss B has a bored part into which a shallow projecting eye C on the
removable side of the case enters to keep all concentric with the eye of the pulley,
and a hole is cast or bored through the centre of these retaining central bosses for a
bolt D to pass through with.sunk recesses for the head and nut to retain and strengthen
the sides at the centre.

page_text: A special improvement consists in forming the pulley or sheave with an inner
projecting flange E on the one side of its eye next the side or cheek of the block on
which the deep eye is cast, and in forming this flange with ratchet teeth, into which
a vertical sliding pawl F works through the bottom part of the eye, sliding up into
the recess formed for the head of the centre bolt, with a slot on its outer end working
on a collar part of the head of the bolt as a guide for the ratchet pawl, which works
radially up and down gliding over the teeth as the pulley is turned by the wire rope
in raising the lug sail; and when the hoisting is stopped the pawl falls into the nearest
ratchet tooth and holds the pulley from turning in the backward direction. The inner
sides of the case are formed with narrow projecting segments over the edges of the
pulley to guide the rope truly on to the groove and prevent it riding on its edges.
When the two parts of the case are put together with the pulley mounted within on
the projecting eye and antifriction rolls, and secured as described by the corner and
centre bolts, the whole is ready for inserting the rectangular case firmly within the
large slot or mortice formed for it in the head of the mast, to which it is secured by
two central end rivets or bolts passing through the case and mast. The wire rope
from the sail is passed over the pulley which turns and acts all as described when the
sail and wire rope is hoisted or lowered.
In the case mentioned where the sheave is mounted on the solid eye B and lubri-
cated by oil, the ratchet teeth E would preferably be cast or formed in the centre of
the hollow eye of the pulley; and the solid eye on the case would be made large and
hollow, and have the check formed in the centre of the solid boss for the radial
pawl F passing down into these ratchet teeth, & the pawl would rise and fall radially
in gliding over the ratchet teeth on the middle of the central securing bolt D instead
of on the end of it as in the former arrangement, as the pulley was turned in the
hoisting direction, but would fall and secure the pulley from turning backwards when
the hoisting ceased; otherwise this arrangement would be of the same construction
as the former.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is ;
The combination of large hollow bearing, antifriction rollers, ratchet and pawl
herein described to hoisting pulley block sheaves and as adapted to masthead
sheaves.
Dad thin 10th Jane of Avant 1800
W. L. MITCHELL, JUNR.