IMPROVEMENTS IN FIXING THE BLADES OF SCREW PROPELLERS TO THE BOSSES
Year: 1883

page_text: LETTERS PATENT to Edward Philemon Timmins, and Joseph Rose, both of
Cardiff in the County of Glamorgan, for an Invention of IMPROVEMENTS IN
FIXING THE BLADES OF SCREW PROPELLERS TO THE BOSSES
PROVISIONAL SPECIFICATION left by the said Edward Philemon Timmins
and Joseph Rose at the Office of the Commissioners of Patents on the
24th February 1883.
EDWARD PHILEMON TIMMINS and JOSEPH ROSE, both of Cardiff in the County
of Glamorgan, "IMPROVEMENTS IN FIXING THE BLADES OF SCREW PROPELLORS
TO THE BOSSES,"
This invention consists in shaping the propellor blades, at the root or end fitting
into the boss, to the form of a wedge-shaped tennon or shoulder, corresponding
dovetailed recesses being sunk in the propellor boss, at the desired angle, to receive
the blades which are secured in place by keys or wedges inserted, one on each side
and from opposite ends, between the said tennons or shoulders and the sides of the
said recesses in the boss. The keys, which are tapered both in the direction of their
length and breadth, or longitudinally and transversely, are furnished at their outer
ends with a shank or projection having screw-threads cut thereon to receive a nut
which, bearing against the face of a recess formed in the boss, prevents the keys
from sliding backwards. The pitch of the propellor blades is capable of adjustment
and variation by altering the degree of taper of the keys.
Under a modification of this invention, one key only is required, and a flange is
formed along the diagonal recess or groove in the boss. The blade is secured, on
one side, to this flange by bolts, and the key is inserted between the tennon or
wedge-shaped shoulder of the blade, on the other side, and the side of the recess or
groove.
By this invention, economy over the present methods of preparing both the
propellor blades and bosses is effected, labour in fixing is reduced and attachment
and detachment, being simple, may be readily effected and without necessitating
the docking of a ship or the discharge of cargo.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Philemon Timmins and Joseph Rose in the Great Seal
Patent Office on the 13th August 1883.
EDWARD PHILEMON TIMMINS and JOSEPH ROSE, both of Cardiff in the County
of Glamorgan IMPROVEMENTS IN FIXING THE BLADES OF SCREW PROPELLORS TO
THE BOSSES
Our said invention consists in shaping the propellor blades, at the root or end
which fits into the boss, in the form of a wedge-shaped tennon or shoulder,
corresponding dovetailed recesses or grooves being sunk in the propellor boss, at the
desired angle, to receive the blades which are secured in place by keys or wedges
inserted, one on each side and from opposite ends, between the said tennons or
shoulders and the sides of the recesses or grooves in the boss. Each key, tapered
in one or more directions as desired, is furnished at one end with a shank or
projection having screw threads cut thereon to receive a nut and washer which,
when screwed into place, prevent any "slacking back" action.
And in order that our said invention may be properly understood, we now
proceed more particularly to describe the same, reference being had to the
accompanying sheet of illustrative drawings and the figures and letters marked
thereon.
Figs 1 and 2 represent respectively an end elevation and a side elevation of a
screw propellor the blades of which are secured in the boss in accordance with one
method under which our invention is applied. Fig. 3 is a sectional plan, the
section being taken immediately beyond the periphery of the boss.
At the root, the propellor blades A are shaped to the form of a wedge-shaped
tennon or shoulder. Corresponding dove-tailed recesses or grooves are sunk in the
boss B, at the desired angle, to receive the blades which are secured in place by the
keys or dges O inserted, one on each side and from opposite ends of the boss.
The keys or wedges C, a side elevation and plan of which are shown at Figs 4
and 5, are furnished at one end with a shank or projection e having screw threads
cut thereon to receive the nut d and washer o which, when screwed into place, in
the recesses formed for their reception in the boss, prevent the propellor blades
from "slacking back."
Figs 6 and 7 represent respectively an end view and sectional plan of a
modification of our said invention under which wedges or keys are dispensed with.
The root of the blade A is formed to fit closely in the recess or groove b sunk in
the boss B, and "slacking back" is prevented by the guard ring G secured to the
boss by means of the bolts g. The ordinary propellor nut may be made to serve
the latter purpose.
Under the modification shown at Figs 8 and 9, the root of the blade A is secured
in place in the recess or groove b by means of the bolts i extending through the
root of the blade and through the sides of the grooves. If desired, bolts may be
used on one side only, and a key or wedge be driven on the other side between the
root of the blade and the side of the dove-tailed recess.
Under this invention, economy in preparing both the propellor blades and bosses
is effected, labour in fixing is lessened, and attachment and detachment, being
simple in method, may be readily effected without necessitating docking of a ship
or discharge of her cargo.
Having now described our said invention and some of the modes in which the
same may be practically carried into effect, we claim as the invention secured to us
by the herein before in part recited Letters Patent.-
Fixing the blades of screw propellors in the bosses by fitting the wedge-shaped

page_text: roots into corresponding grooves formed in the bosses, and maintaining the same in
place by means of wedges, keys, bolts or guard rings, substantially as described and
shown on the accompanying sheet of drawings.
In witness whereof we, the said Edward Philemon Timmins and Joseph Rose
have hereunto set our hands and seals this thirty first day of July in the year
of Our Lord one thousand eight hundred and eighty three.