IMPROVEMENTS IN ANCHORS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Thomas Thomson at the Office
of the Commissioners of Patents, with his Petition, on the 13th
August 1872.
I, THOMAS THOMSON, of Bluff Harbor, Otago, New Zealand, now of
No. 8, Southampton Buildings, London, Harbour Master, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN ANCHORS,"
to be as follows :-
My said Invention relates first to furthur improvements in the
anchors described in the Specification of Letters Patent bearing date tho
4th day of January A.D. 1872, No 32, which improvements are designed
to increase the strength and holding capacity of the anchor, and
diminish the cost of its manufacture.
As described in the said former Specification the stock and shank are
secured together by means of a set screw passed through the shank into
grooves in the ends of the stock, but according to my present Invention
the parts forming the joints of the said stock and shank are either
clinched, forclocked, or connected by eyes. The ends of tho said stock

page_text: may be either round, or of any other convenient shape in transverse
section. I make the said stock of one piece, or two or more pieces, and
it may be cither open in the central portion or solid throughout, and
may be arranged with its sides either parallel with the shank or trans-
verse to the same. Or it may be made of angle or T iron, or of iron t
flanged on both edges. I also make the shanks of angle or T iron, or
flanged iron. I sometimes turn or bend the ends of the shanks outward
to assist in canting the anchor.
In the said former Specification the flukes are shown terminated at a
point of the arm above which the latter is bevelled on the inner side, 1
but according to my present Invention the flukes may extend to any part
of the arm or throat, the latter being bevelled or not bevelled, as desired.
I make the crown of one piece of wrought iron, bent to the required
shape. It may have the corners or toggles welded on or may be made
without them. I also make the said crown of cast steel or cast iron. ]
When the said crown is in two picces jointed at the centre, I make
the joint either level or half checked; I prefer to make the flanges or
outer edges of the arms corrugated to increase the canting of the
anchor.
I have heretofore constructed these anchors with the two parts of the
shank connected by a series of bolts passed through them, there being
a number of holes in the shank, wherein the said bolts may be
adjusted to vary the angle of the flukes when the anchor takes the
ground, but I now employ only one bolt for securing these parts, and
effect the variation of the angle of the flukes by means of washers or
rings of different diameters, either of which may be placed on the said
bolt.
Tho flukes of the single armed anchor described in the said former
Specifiation may be either rivetted or welded upon the arm.
The said Invention relates, secondly, to modifications of these im-
provements, whereby I convert an ordinary solid anchor into a hinged
anchor, or utilize parts of such solid anchors in the construction of my
improved anchors. I take an ordinary solid anchor and cut off its
shank close to the crown. The arms are then bent or curved into the
required shape, and has a hole made in it for the reception of the hinge
pin. Or the crown may be divided at the centre into two arms which
are jointed together and to the shank. If it is desired to retain the old
•

page_text: shank and stock 1 attach to the shank by rivetting, welding, or other--
wise two plates that form jaws, between which the arms are fitted, the
hinge pin being passed through the said jaws.
I sometimes connect the two arms to the shank by two separate hinge
pins, and in order to prevent the obstruction of the same by sand or
other substance lodging in the joint between the two arms I bevel the
edges of the latter so that their ends will not have sufficient surface to
hold any substances between them.
"
If it is desirable that the anchor should have a new shank and stock,
the same may be constructed as above described or as described in the said
former Specification. If the shank is made of two metal bars, the same
may have the form of a triangle at the portion nearest the stock, the said
bars at the remaining portion of the shank being brought together
parallel with each other. The said arms are rivetted or otherwise secured
to the outer ends of the stock as herein-before described. Or the said
shank may have its two bars or pieces placed together and secured by
rivetting or otherwise, to the centre of the stock. The lower ends of the
two bars form the jaws for the reception of-the crown or arms. -
To avoid the necessity of forming toggles on the flukes I provide the
shank of the anchor with a canting disc or movable arm to support the
flukes and ensure their taking the ground.