CERTAIN IMPROVEMENTS IN THE CONSTRUCTION, MAKING, OR MANUFACTURING OF SHIPS' ANCHORS, AND WINDLASSES, AND CHAIN CABLES, OR MOORINGS
Year: 1813

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BRUNTON, of Cooper's Row, Crutched Friars, in the City of London, Merchant,
send greeting.
WHEREAS His present Majesty King George the Third, by His Letters
Patent under the Great Seal of Great Britain, bearing date at Westminster,
the Twenty-sixth day of March now last past, did give and grant unto me, the
said Thomas Brunton, Ilis especial licence, full power, sole privilege, and
authority, that I, the said Thomas Brunton, my executors, administrators, and
assigns, and such others as I, the said Thomas Brunton, my executors, admi-
nistrators, or assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "CERTAIN
IMPROVEMENTS IN THE CONSTRUCTION, MAKING, OR MANUFACTURING OF SHIPS'
ANCHORS, AND WINDLASSES, AND CHAIN CABLES, OR MOORINGS;" in which said
Letters Patent there is contained a proviso, obliging me, the said Thomas
Brunton, by an instrument in writing under my hand and seal, particularly to
describe and ascertain the nature of my said Invention, and in what manner
the same is to be performed, and to cause the same to be inrolled in His said
Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said recited Letters Patent, as in and by
the said recited Letters Patent, reference being thereto had, will more fully
annear

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Brunton, do hereby declare that my said improvements in the con-
struction, or making, or manufacturing of ships' anchors, and windlasses, and
chain cables, or moorings, are described and specified in manner following,
reference being had to the Drawings or Figures hereunto annexed, that is
to say:
In manufacturing ships' anchors, in place of the common method of joining
the arms to the shank, which is by welding, and which requires the iron to be
so frequently heated as often to destroy and injure its tenacity, I make the
shank in one piece, and the two arms in another piece, as follows:-The piece
intended for the arms is formed into shape, and of such a thickness or
substance in the middle as to allow a hole to be made through the centre of
the solid piece to receive the thick end of the piece which forms the shank,
and the said hole in the arm piece is made somewhat conical or bill-mouthed,
so that no strain can separate the arins from the shank, by which means I
avoid the necessity of endangering the solidity of the materials, only one heat
being necessary to bring the thick end of the shank and the hole in the arm
piece into perfect contact, for I do not trust the strength of this important
part of the anchor to a union effected by welding, which may, and generally
is defective, but to the impossibility of drawing a thick, solid, conical piece
of iron through the smaller apperture of a conical opening into which it is
fitted. The arms with their flukes may be made of good. cast iron, taking
care to allow them sufficient substance. But anchors should not only have
the utmost strength which can be attained, but also be made as secure as
possible against the danger of being lost by the cable or chain by which they
are attached to the ship giving way. Cables made of hemp can never be
rendered safe, but chain cables may.
To convey correct ideas respecting my improvements in the construction of
chain cables or moorings, it is necessary that I should point out and illustrate
the principles which should guide the workman in his operations. These
when thoroughly understood will not only enable him to avail himself of my
improvements after the expiration of the said term, but will qualify him to
detect, and consequently to avoid those errors and mistakes in form and
construction which prevail more or less in all the chains that have hitherto
been employed for cables or moorings.
The object to be gained is the greatest possible strength from a given
quantity of materials, keeping in mind the direction in which the strain is to
be borne. If the tendency of a strain applied to a link of a bad form be once
properly conceived, a great step is gained towards the adoption of a good form.
F

page_text: Let A, B, Fig. 1, represent a circular link of a chain, the substance of the
iron one inch. Let tho outer circumference be fifteen inches, and let the
inner circumference be nine inches. If receding forces be applied to the
two links C and D (shewn in section), pulling C towards E, and D towards F,
the ultimate tendency of the effort of such forces is to change the form of the
circular link into one which shall have round ends, and parallel sides as
Fig. 2, but a very slight examination will shew that before this can be effected
the link must be destroyed, for in such a circular link the corresponding
segments of the outer and inner circumferences are in the proportion of five
to three, and therefore every effort to increase the distance between C and D,
or in other words to make the parts A and B approximate, must disturb the
relative position of every particle of the metal, and operate to destroy its
corpuscular attraction. Thus, (in Fig. 1) the segment M, N, of the outer
circumference, being taken equal to three inches, the corresponding segment of
the inner circumference will be one inch and eight-tenths of an inch. If this
segment of the link is by the force of a strain to be changed from a curved
to a straight form (as in Fig. 2), the corresponding segments of the outer and
inner circumference must be brought to one length, to effect which the
matter contained in three inches of the outer circumference must be com-
pressed into one inch and eight-tenths of an inch, or the matter which now
occupies only one inch and eight-tenths of an inch in the inner circumference
must be made to dilate itself to three inches without losing its cohesion, or
the required compression and expansion must be divided between the two,
all of which are impossible without a derangement of the relative postion of
every particle in the mass.
To be brief, the matter in this part of the outer circumference may be
conceived to present an infinite number of fulcrums over which the said
receding forces by an effort to render the curve straight must rupture and
seperate the matter of the inner circumference. Nor is this the only mischief
that must occur, as will appear by a consideration of what must take place
where the link folds round C and D, for the larger semicircles in Fig. 2,
each containing four inches and an half (nearly) of the outer circumference,
answering to two inches and seven-tenths of an inch of the inner circumference
of Fig. 1, must now correspond to the cemicircumference of the links C and
D, which are each only one inch and an half (nearly), so that in these parts
the effect produced by the action of the said forces would be the same as in the
former, but reversed in its operation, that is, the matter in these parts of the
inner circumference presents an infinite number of fulcrums, over which the
outer circumference must be ruptured and separated by the said forces.. A

page_text: circular is therefore a bad form, but from the foregoing it is obvious that if
the parts A and B of the circular link, Fig. 1, can be prevented from approxi-
mating each other, the evil that has been pointed out will be lessened.
Suppose a stay A, G, B, to be introduced for this purpose, and as before, let
receding forces be employed in the directions C, E, and D, F, what will be
the effect? The circular link will now be able to. resist. a greater force than
before, having two points of support; but the unsupported parts between
the points A, C, B, and D willby the effort of the said force endeavour to
assume a quadrilateral form, somewhat like Fig. 3, a change that cannot
be effected without a derangement of the matter in the link, which must
rupture and destroy it; such stays as A, G, B, (Figs. 1 and 3) have been used
in chains, but such a stay only supports two opposite points in the link, and
I have shown that the tendency of receding forces applied as before described
is to straighten, and consequently to rupture the parts that are still left
unsupported.
My said improvements in chain cables or. moorings are founded on con-
siderations drawn from the facts that have been alluded to. If a circular
link, instead of being supported only in the two opposite points A and B, have
its opposite sides supported by a stay embracing two considerable and opposite
segments, suppose H, I, and K, L, by the stay H, I, K, L, taking care to
leave such openings as shall allow sufficient play for the links to be received
into it, the link will be much stronger than with such a stay as A, G, B, but
still the link will prove to be of a bad form, for the tendency of receding
forces applied as before would break the piece. M, O, K, C, H, over the point
C, as a fulcrum, and the piece N, P, L, D, I, over the point D, as a fulcrum.
And, moreover, even if circular links could be made unobjectionable as to
strength, they should be avoided on account of the greater weight of metal,
which a given length of chain would require, than when formed of links of a
less exceptionable form. We have seen that the tendency of receding forces
applied to curved links is to draw portions of them into straight forms, and
hence it follows that twisted links of every kind should be avoided where
strength is required, for such links, even if their opposite sides be supported
by an interposed stay like A, G, B, must by the application of a sufficient
strain untwist themselves to become straight, and thus have the arrangement
of their particles disturbed. As the tendency of forces applied as before-
imentioned to curved or twisted links is to convert the curves or distortions
into straight positions as above described, it follows that links presenting in
their original construction straight parts between the points of strain are the
strongest that can be made with an equal portion of metal, and hence links

page_text: with parallel sides and cemicircular ends would in every caso be preferred,
wero it not necessary to the quality of good chain that it should be able to
resist lateral violence as well as a general strain operating by stretching.
Suppose that by any accident the link, Fig. 2, should have its ends drawn
towards Y and Z, while a resisting body at X opposes its motion in the
direction of the applied forces: the side of the link next to X would be bent
inward, and if in such a link, a stay like A, G, B, were introduced, then the link
would be solicited by the said force to assume a form somewhat like Fig. 4.
From the preceeding considerations it is evident that of all the forms and
constructions that can be given to a link, that form and construction which
shall be able to convert a lateral into an end strain, by yielding proper support
to the opposite sides of the link, is the one that should be preferred, and of such
a form and construction is the link, Fig. 5, with my broad-ended stay intro-
duced between the sides of the link; for if this link (which presents its principal
substance, and all its points of resistance in the same place,) be drawn towards
a and b, against an obstacle c, it is apparent from a bare inspection, that the
parts d, e, and d, f, which are supported by the parts g, e, and g, f, must be
drawn asunder before the link can give way, for the matter in e, g, and f, g,
cannot be made to penetrate itself, and the two sides are compelled to retain
their relative position by my interposed broad-ended stay h, a cross section of
which through its middle is shewn in Fig. 6.
I need hardly add that at the time that the stay h is introduced, the link is
wide enough to receive it, and the link being red hot at the time of its
introduction, and being pressed home to the stay by a die or press, or any
suitable mechanical means, takes a fast hold of it, and retains it in its place.
Other ways of introducing and retaining in its place my broad-ended stay
may be employed, but I have found the preceding exceedingly simple and
efficatious.
On my broad-ended stays I have only farther to remark, that they should
embrace the whole or the greater portion of the opposite curved parts of the
middle of the link, and even if the middle of the link be made to form two
opposite obtuse angles, the ends of the stay should not embrace much less
than the proportion exhibited in Fig. 5; but in making the said ends to
embrace any larger portion, provided sufficient room is left for the play of the
links received into it, there will be no harm, only the chain will thereby be
rendered heavier, which may sometimes though not generally be desirable.
For veering away cables in general, and particularly chain cables, a good
windlass has long been a desideratum.
My improvement in the construction of ships' windlasses consists in making

page_text: the same or parts
thereof to revolve on an axis, in place of having the whole
in one solid piece. The axis A, B, Fig. 7, receives upon the square part C,
the pall ratchet D, Fig. 8, and upon the cylindrical parts E and F it receives
the two pieces G and H, Fig. 8, round which the chain or cable receives one or
more turns. The said pieces G and H, are locked into D, or kept out of
geer at pleasure by the checks or stops a, a, a, Figs. 8 and 9, and the
counter checks or stops b, b, b, b, Figs. 8, 10, and 11, or by any other
means. And when out of geer they are kept asunder by any proper
formed prohibiter let down between them, as the piece, Fig. 12. The advan-
tage of this construction is simply this:-In veering away the cable or chain
the pieces. G and H, having power to revolve on their axis, the friction-
and consequent wear and injury of the cable or chain which is inseperable
from the usual method of allowing the same to be rubbed in their whole
course against a stationary windlass, is entirely avoided. The construction just
described has also this advantage, that the motion of the pieces G and H may
be regulated by the contrivance called a break, and which being in common.
use for regulating velocities by means of friction needs no description.
In witness whereof, I, the said Thomas Brunton, have hereunto set my
hand and seal, the Twenty-fourth day of September, in the year of our
Lord One thousand eight hundred and thistoon
Inrolled the same Twenty-fourth day of September, in the year above
written.