Improved Means for Securing Propeller Blades to their Bosses
Year: 1899

page_text: Date of Application, 3rd Jan., 1899
Complete Specification Left, 21st June, 1899-Accepted, 29th July, 1899
PROVISIONAL SPECIFICATION.
Improved Means for Securing Propeller Blades to their Bosses,
I, LEWIS DAVIES, of No. 5, Fenwick Street, Liverpool, England, Ship Owner,
temporarily residing at Scott's Hotel, Collins Street, Melbourne, in the Colony
of Victoria, do hereby declare the nature of this invention to be as follows:-
:―
This invention relates to the means used for securing propellor blades to their
bosses and has been devised in order that such blades may be held more securely
in position than when fixed in the ordinary way.
Hitherto it has been usual to screw a cap over the ends of the studs or bolts
used for securing the blades to the boss of the propellor but this cap has been
liable to work loose and thus the blade has sometimes been either lost or broken.
Now according to my invention I form a hole preferably through the centre
of this cap and I pass a set screw through such hole and screw it into a hole in
the end of the bolt. The threads on this set screw are formed in the reverse direction
to those on the cap that is if the one has right hand screw threads the other has
left hand screw threads and vice versa. This set screw has a small passage through
it from end to end.
This invention effectually prevents the blade working loose because any back-
ward rotation of the cap will be taken up by the reverse movement of the set
screw.
As an additional safeguard the set screws might be secured by pins or other set
Borews against accidental rotation.
Dated this Twenty-fourth day of November One thousand eight hundred
and ninety-eight.
COMPLETE SPECIFICATION.
Improved Means for Securing Propeller Blades to their Bosses,
I, LEWIS DAVIES, of No. 5, Fenwick Street, Liverpool, in the County of
Lancashire, Ship Owner, 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 relates to the means used for securing propeller blades to their
bosses and has been devised in order that such blades may be held more securely
in position than when fixed in the ordinary way.

page_text: Hitherto it has beon usual to screw a cap-nut over the end of each of the studs
or bolts used in securing the blades of the propeller to its boss but these cap-nuts
have been liable to work loose and as a result the blades have sometimes been
either lost or broken.
Now according to my invention I employ studs or bolts and cap-nuts con-
structed as shown in the accompanying drawings of which
Fig. 1 is a central longitudinal section partly in elevation through one of the
studs or bolts that secure the blade to the boss; and Fig. 2 is an end view.
1 is the propeller boss into which the stud or bolt 2 is screwed and 3 is one
of the blades through the flange of which the stud or bolt 2 extends. 4 is a cap-
nut screwed upon the end of the bolt 2 and formed with an aperture 5 prefer-
ably of tapering form; as shown. In the end of the stud or bolt 2 there is also
formed a correspondingly arranged hole 6 which is screw-threaded and into
which is screwed a set screw 7 whose threads are formed in the reverse direction
to those of the cap-nut 4; that is, if the one has right hand screw threads, the
other has left hand screw threads. The set screw is formed with a tapering.
shoulder part to fit the aperture 5. The bolt 2 is formed with a small passage 8
extending from the hole 6 to its inner end, and the set screw 7 is also formed
with a small passage 9 from end to end so that water can escape from the holes
which receive the stud or bolt 2 and the set screw 7 as they are screwed into
them. As will be understood backward movement of the cap-nut 4 will be pre-
vented by the head of the set screw 7 which, owing to the friction between it
and the cap nut, will tend to turn with and in the same direction as the cap-nut;
the set screw 7 thus tends to become screwed further in, as the cap-nut tends to
become unscrewed. The set screw 7 is formed at regular intervals with aper-
tures 10 and the cap-nut with holes 11 arranged at irregular intervals; by bringing
one or other of the recesses 10 over one of the holes 11 and then screwing into
the latter a pin or screw 12 accidental unscrewing of the set screw 7 will be
prevented. The arrangement of the holes 10 and 11 is such that in no case is
more than a slight turning movement of the act screw necessary to bring one or
more of the holes 10 in line with one or more of the holes 11; thus whenever
the set screw 7 is screwed home or practically so it can be secured by the pin or
screw 12.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:
The improved means for securing propeller blades to their bosses comprising
studs or bolts screwed into the boss and each formed with a screw-threaded hole,
a reversely screw threaded.cap-nut formed with a central aperture, and a set screw
that extends through said aperture into the hole in the stud or bolt, and is
adapted to be itself secured in place by one or more pins or other set screws,
substantially as described with reference to and shown in the accompanying
drawings.
1 11.
01 1 1
T
1000