Improvements in or relating to Ships' Screw Steering Gears.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Ships' Screw Steering Gears.
I, THOMAS LINTON LIVINGSTON, of Dunedin House, Jarrow-on-Tyne, Naval
Architect, do hereby declare the nature of this invention to be as follows:-
The principal object of my invention is to dispense with the necessity, when
changing the steering power from hand to steam, or from one steering motor to
another, for disconnecting the steering gear with the one motor and connecting
it with the other, thereby overcoming the difficulty and delay hitherto incidental
to this operation.
The usual arrangement of screw-steering gear as hitherto adopted, consists of a
substantial screw shaft, having right and left-handed threads, on which are fitted
two nuts, one in way of each of the threads. These nuts are attached to sliding
sleeves, which travel along guide rods, fitted at each side of the screw shaft, the
sleeves being connected by means of connecting rods, with a crosshead fixed on
the rudder. The vessel is steered by rotating the screw shaft, which causes the
nuts to travel along the screw threads, and thereby actuate the cross-head and
rudder.
My invention consists in fitting the nuts, so that they will be able to rotate,
either in bearings in the sliding sleeves or otherwise, and making each nut or a
part thereof with projections all round the circumference, in the form of a toothed
wheel; also in introducing an additional shaft, having in way of the travel of the
nuts longitudinal grooves or projections around the circumference, in the form
of a toothed wheel, and fitting this shaft so that, when, rotated, the toothed part
will fit into and work smoothly with the toothed part of the nuts, and cause the
latter also to rotate, and travel along the threads on the screw shaft.
To effect the object of my invention, the hand or other steering motor is con-
nected with one of the shafts, and the steam or other steering motor with the
other, so that if the motor in connection with the toothed shaft, be kept sta-
tionary, the rudder can be actuated as before described by rotating the screw
shaft; and if the motor in connection with the screw shaft be kept stationary,
the rudder can be actuated by rotating the toothed shaft, thereby causing the nuts
to rotate and travel along the screw shaft.
Consequently a change of steering motor can be effected by simply stopping
the one motor, and setting the other in motion, or if both motors be simultaneously
set in motion they will work smoothly together and assist each other.
Clutches, couplings, or other gearing can also be introduced to enable each
of the steering motors to be connected with either of the shafts.
In the foregoing description reference is made only to the usual centre screw
shaft arrangement, but my invention is applicable to any other arrangement of
screw steering gear; for example two screw shafts may be used, one with right-
handed and the other with left-handed threads, in combination with one or more
toothed shafts; or the nuts may be made stationary and the screw shafts arranged

page_text: to travel through the nuts, the connecting rods from the cross-head on the rudder,
in the latter case, being connected to the screw shafts, and an ordinary toothed
wheel, substituted for each toothed shaft; or other modifications may be adopted.
It will be evident that my invention is not limited only to the details of con-
struction as herein before described; for example, plain nuts may be used, and
the toothed parts made separate, and keyed or otherwise secured to the nuts;
and in a similar manner a plain shaft may be used, and the toothed part made
separate, and keyed or otherwise secured to the shaft; or other modifications may
be adopted.
Dated this Oth day of M 1000
Improvements in or relating to Ships' Screw Steering Gears.
I, THOMAS LINTON LIVINGSTON, of Dunedin House, Jarrow, in the County of
Durham, Naval Architect, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
This invention has reference to improvements in or relating to ships' screw
steering gears of the kind adapted to be operated by one of two driving means
either of which can be employed alternatively and which may comprise for example
hand and steam driving means or it may be two separate driving motors. Here-
tofore in changing from one driving means to the other, say in the case of break-
down or for other reason, it has been necessary to disconnect the steering gear
from the one driving means and connect it to the other. Now the principal object
of this invention is to dispense with such disconnecting and connecting opera-
tions thereby obviating the difficulties and delay incidental thereto.
One arrangement of screw steering gear as hitherto frequently employed com-
prises a shaft formed with right and left hand screw threads and provided with
two nuts one right hand and the other left hand. Each nut is attached to a
sliding sleeve or collar sliding on guide bars conveniently situated at opposite
sides of the screwed shaft, the sliding sleeves or collars being suitably connected
by means of connecting rods with a cross beam mounted on the rudder head.
Rotation of the screwed shaft causes the nuts to travel thereon in opposite direc-
tions and move with them the sliding sleeves whereby the cross beam on the
rudder head is turned and the ship steered thereby.
Steering gear of this description but embodying the present invention is illus-
trated in the accompanying drawings which show, by way of example, steering
gear adapted to be operated by hand and steam power, Fig. 1 being a side eleva-
tion, Fig. 2 a plan partly in Eorizontal section, and Fig. 3 a cross section on the
line t x, Fig. 1.
For steering by steam power there is employed an ordinary screwed shaft 1
formed with right and left hand screw threads 2 and 3 and provided at one end
with a gear wheel 4 which engages with another gear wheel 5 fixed to a shaft 6
driven by the engine. Upon the screwed shaft 1 are provided two screwed nuts 7
one on each of the oppositely screw threaded portions of the shaft each nut being
rotatably mounted in a sleeve 8 but fixed endways therein by means of a collar
screwed on the said nut and secured in place by screws 7b. The sleeves 8 are
adapted to slide on guide rods 9 and are suitably connected, as by means of
links 10, to a part or parts for conveying the movement of the sleeves to the rudder

page_text: In the example shown the links 10 are connected to a crosshead 11 fixed to the
rudder head 12.
For adapting the steering gear to be operated by another driving means in
accordance with this invention, the nuts 7 are provided with gear teeth 7°, and
upon a spindle 13 suitably mounted in bearings 14 there is fixed a long toothed
pinion 15 in gear with the teeth of both nuts 7. The spindle 13 is connected
with the alternative driving means herein shown as hand wheels 16. As will be
seen the arrangement is such that when the steam operated driving means is
employed, the rotation of the screw shaft 1 produces longitudinal movement of
the nuts 7 in opposite directions, the said nuts being prevented from rotating by
the engagement of their gear teeth with the teeth of the pinion 15, and that on
operating the hand wheels 16, the shaft 6 being at rest, the rotation of the
pinion 15 produces rotation of the nuts 7 thereby causing the latter to move
longitudinally in opposite directions on the screwed shaft, the nuts in each case
operating the crosshead 11 and rudder head 12.
If desired the long pinion 15 may be made shorter by being provided with
flanges and adapted to slide endways on the spindle 13; or instead of a long
pinion such as 15, a separate pinion may be provided for each nut. Figs. 4
and 5 show respectively in vertical section and end view one of the nuts and its
pinion draw to a larger scale than the previous figures. The gear teeth 7° of
the pinion 7 engage with similar teeth of a shrouded pinion 17 which is secured
on the spindle 13, as by a key 17 in the pinion fitting a groove or keyway 13"
in the shaft 13 so as to be rotated by the latter but capable of sliding freely
endways thereon. The side flanges 176 of the pinion serve to maintain the pinion
and nut constantly in gear.
To enable each of the driving means to be connected with either the screw
shaft 1 or the spindle 13, couplings of any suitable kind, or toothed gearing, may
be employed.
It will be obvious that, as well as being adapted for use with a single shaft
having right and left handed screw threads formed thereon, this invention is also
applicable to various other forms of steering gear, for example, gear comprising
two screwed shafts, the threads of one being oppositely directed to the threads of
the other and each shaft being provided with a nut such as 7 the gear teeth
of which engage with a pinion such as 15, or with shrouded pinions such as 17,
means being provided for simultaneously rotating both of the said screwed shafts
in the same direction.
In steering gear embodying the above described improvements both driving
means are always in gear so that either can be at once, brought into operation.
As the spindle 13 does not carry the weight of the sliding sleeves, or of the
screw nuts and is not subjected to strains from the movements of the rudder
it can be made of comparatively small diameter and thereby be more applicable
for use with hand power. The connection between the screwed shaft 1 and the
spindle 13 is such that though both driving means may be in operation at the
same time whether in the same or in opposite directions they will not obstruct
each other.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:-
1. Ships' steering gear of the kind in which motion is imparted to the rudder
by means of a screw-threaded shaft provided with two correspondingly screw
threaded nuts, or by two screw threaded shafts each provided with a corre-
spendingly screw threaded nut, wherein the nut or nuts is or are provided with
gear teeth adapted to engage with corresponding teeth of a gear wheel or wheels
on a spindle or spindles adapted to be rotated by driving means other than the
driving means for imparting rotation to the said screw threaded shaft or shafts,
substantially as described.

page_text: 2. Steering gear constructed, arranged and operating, substantially as herein-
above described with reference to and shown in Figs. 1, 2 and 3; or modified
according to Figs. 4 and 5 of the accompanying drawings.
Dated this 10th day of Falimony 1900
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.