IMPROVEMENTS IN APPARATUS FOR SECURING MAIN SHEETS' AND OTHER ROPES OR CHAINS WHOSE DIRECTION OF STRAIN IS LIABLE TO FREQUENT VARIATION
Year: 1881

page_text: LETTERS PATENT to Harold Blyth McIntosh, of Great Grimsby, in the
County of Lincoln, for an Invention of IMPROVEMENTS IN APPARATUS
FOR SECURING MAIN SHEETS' AND OTHER ROPES OR CHAINS WHOSE
DIRECTION OF STRAIN IS LIABLE TO FREQUENT VARIATION."
PROVISIONAL SPECIFICATION left by the said Harold Blyth MoIntosh at
the Office of the Commissioners of Patents on the 6th December 1881.
HAROLD BLYTH MCINTOSH, of Great Grimsby, in the County of Lincoln.
"IMPROVEMENTS IN APPARATUS FOR SECURING "MAIN SHEETS AND OTHER
ROPES OR CHAINS WHOSE DIRECTION OF STRAIN IS LIABLE TO FREQUENT
VARIATION."
In ships and other vessels the "main sheet" is usually attached to a pair of
blocks, the bottom block being shackled to an eye fixed to a large piece of wood,
which is bolted rigidly onto the deck, so that the deck bears the full shock when
the boom goes over. At each time that the vessel "goes about" the boom passing
over to the other side of the ship is brought suddenly to a standstill. A great
strain is brought to bear on the "main sheet," and the sudden jerk often causes
the boom or sheet to bo broken. The strain also affects the deck to which the
block is secured, opening the joints and causing it to leak, while the sudden jerk
is felt at the top-mast-head, causing damage to the topmast ropes and other gear.
It is to obviate these injurious results to the vessel that this my Invention is
designed.
To the deck of the vessel I firmly secure a frame, preferably a metal casting,
having two journals, into which are placed the trunnions of a cylinder capable of
swinging freely from side to side; other modes of swivelling the cylinder can be
adopted, such as a ball and socket or a universal joint. A piston is placed insido
the cylinder, and between the piston and the cover of the cylinder an india-rubber
[Price Gd.1

page_text: buffer or other spring smaller in diameter than tho interior of the cylinder, or
otherwise capable of expansion laterally under longitudinal compression. To an
eye in the piston rod I shackle the bottom block to which the main sheet is
attached, and when the sudden strain or shock consequent on the going about of
the vessel occurs its force is ensed by the spring or buffer. The frame, when
trunnions are used, may be so mounted on the deck as to swivel and then turn in
any direction according to the position of the main boom and the angle at which
the main sheet stands with the centre line of the vessel.
I do not confine myself to the exact details described, nor to the one application
of the Invention to main sheets, as it could be used in connection with other ropes
on board which were subjected to violent and sudden strains.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Harold Blyth MoIntosh in the Great Seal Patent Office on the
6th June 1882.
HAROLD BLYTH MCINTOSH, of Great Grimsby, in the County of Lincoln.
"IMPROVEMENTS IN APPARATUS FOR SECURING MAIN SHEETS AND OTHER
ROPES OR CHAINS WHOSE DIRECTION OF STRAIN IS LIABLE TO FREQUENT
VARIATION."
In ships and other vessels the "main sheet" is usually attached to a pair of
blocks, the bottom block being shackled to an eye fixed to a large piece of wood,
which is bolted rigidly onto the deck, so that the deck bears the full shock when
the boom goes over.
At each time that the vessel "goes about" the boom passing
over to the other side of the ship is brought suddenly to a stand still. A grent
strain is brought to bear on the "main sheet," and the sudden jerk often causes the
boom or sheet to be broken. The strain also affects the deck to which the block
is secured, opening the joints, and causing it to leak, while the sudden jerk is felt
at the top mast head, causing damage to the top mast ropes and other gear. It is
to obviate theso injurious results to the vessel that this my Invention is
designed.
To the deck of the vessel I firmly secure a frame, preferably a metal casting,
having two journals, into which are placed the trunnions of a cylinder capable of
swinging freely from side to side; other modes of swivelling the cylinder can be
adopted, such as a ball and socket or a universal joint. A piston is placed inside
the cylinder, and between the piston and the cover of the cylinder an indiarubber
buffer or other spring smaller in diameter than the interior of the cylinder, or
otherwise capable of expansion laterally under longitudinal compression. To an
eye in the piston rod I shackle the bottom block, to which the "main sheet" is
attached, and when the sudden strain or shock consequent on the going about of
the vessel occurs its force is eased by the spring or buffer. The frame, when
trunnions are used, may be so mounted on the deck as to swivel and then turn in
any direction according to the position of the main boom and the angle at which
the main sheet stands with the centro line of the vessel.
I do not confine myself to the exact details described, nor to the one application
of the Invention to main sheets, as it could be used in connection with other ropes
on board, which may be subjected to violent and sudden strains.
Reference being now had to the accompanying Drawings, in which liko letters
of reference represent like parts. Figure 1 is an elevation of the apparatus as it
would be seen upon the vessel when looking in a fore-and aft direction; Figure 2
is a vertical section, and Figure 3 is a plan.
A is the cylinder supported upon trunnions B carried in bearings C of standards
or framework D, so as to be capable of swinging or oscillating, as shown in the
dotted lines in Figure 1; E is a strong spring, by preference made of indiarubber,
down the centre of which passes the plunger rod F, having a nut F¹ screwed on its
lower end, and a plate, washer, or piston Fabutting against the spring. Another
plate or washer F³ is placed round the plunger rod on top of the spring. The
plunger rod F passes through the top of the cylinder, as shown in Figure 2, and
by links G and pins H it is connected with the block I, which communicates with
the boom by ropes, &c., in the ordinary manner. As the boom swings from side to
side of the vessel the cylinder adapts itself to the motion by swinging on its
trunnions, as shewn in Figure 1 (dotted lines). Owing to the radial motion of tho
boom there is a tendency to pull the plunger rod F over when the boom approaches its
extreme swing to either side; provision is made for this by elongating the holo in the

page_text: cylinder top in the required direction A', as shown in Figures 2 and 3. It will be
observed that the top end or cover is cast on the cylinder and the bottom one
separate and bolted on; this is the best arrangement, as if the top cover be
separate the whole strain comes upon the bolts which hold it, whereas by the
arrangement shown the strain is taken by the solid metal. Of course, however,
I can make the top cover removable if required. In the Drawings A³ is the bottom
cover.
Having now described my Invention, and the method of performing the same,
I wish it to be understood that what I claim and desire to protect under the
hereinbefore in part recited Letters Patent is,—
The hereindescribed spring "buffer" or apparatus for securing and easing the
strain upon "main sheets" and other ropes or chains whose direction of strain is
liable to frequent variation, substantially as set forth and shown.
In witness whereof, I, the said Harold Blyth M*Intosh, have hereunto set my
hand and seal, this Fifth day of June, in the year of our Lord One
thousand eight hundred and eighty two.