IMPROVEMENTS IN STEERING GEAR
Year: 1885

page_text: I, THOMAS ARCHER, junior, of Dunston Engine Works, Dunston, Gateshead, in
the County of Durham, Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN STEERING GEAR to be as follows:-
My invention of Improvements in Steering Gear consists in an arrangement of
worm working in a worm wheel or in a segment of a worm wheel fixed to a spindle
carrying the chain or rope sheave round which the chain or rope is wound which
actuates the rudder the worm before referred to is fixed on the spindle of the
steering wheel and is so proportioned as to pitch as to make steering easy.-By
this arrangement I obtain the advantage of having the steering gear self holding;
that is to say the strain on the rudder is by this gear so indirectly transmitted to
the steering wheel that the tendency of the rudder to move from any position in
which it may be placed is restrained in a much more effectual manner than by
a mere arrangement of multiplying wheels, and the necessity to hold the wheel is
avoided. Another part of my invention consists in fixing a pointer on the spindle
of the chain wheel and an index below it so as to indicate to the steersman the
position of the helm at all times.-This part of my invention is applicable to other
forms of steering gear as well as that particular form described above.

page_text: I, THOMAS ARCHER, junior, of Dunston Engine Works, Dunston, Gateshead, in
the County of Durham, Engineer, do hereby declare the nature of my invention
for IMPROVEMENTS IN STEERING GEAR, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement
My invention of Improvements in Steering Gear consists in an arrangement of
worm working in a worn wheel, or in a segment of a worm wheel fixed to a spindle
carrying the chain or rope sheave round which the chain or rope is wound which
actuate the rudder, the worm before referred to is fixed on the spindle of the
steering wheel and is so proportioned as to pitch as to make steering easy-By
this arrangement I obtain the advantage of having the steering gear self holding;
that is to say, the strain on the rudder is by this gear so indirectly transmitted to
the steering wheel that the tendency of the rudder to move from any position in
which it may be placed, is restrained in a much more effectual manner than by
a mere arrangement of multiplying wheels, and the necessity to hold the wheel is
avoided.
Another part of my invention consists in fixing a pointer on the spindle of the
chain wheel and an index below it so as to indicate to the steersman the position
of the helm at all times.-This part of my invention is applicable to other forms of
steering gear as well as that particular form described above.
Having thus described the nature of my Invention I will proceed more
particularly to describe the manner in which the same is to be operated reference
being bad to the drawings hereto attached.
A. A. Fig. 1. and Fig. 2 is the steering wheel of any ordinary construction the
spindle of which is provided with a screw B. B. gearing into the worm wheel
segment C. C.-The worm wheel segment is keyed fast upon the spindle D. D. on
which is also. keyed the chain wheel E. E. on this chain wheel the chain for
actuating the rudder makes a complete turn in spiral grooves as usual being
fastened to the wheel at one part so as to be actuated by the wheel without
slipping. The pointer I have mentioned as indicating to the steersman the position
of the helm is shewn at F. F. and the index is shewn at G. G the former being fast
on the spindle carrying the worm wheel and the latter fast on the frame work of
the apparatus the gearing of the whole being such as that the helm is in the centre
where the index is, and hard over to either side by so much movement of the
worm wheel spindle as is required to traverse the index by the pointer in either
direction. I do not confine myself to these details of construction which are
capable of variation in many ways and which I have chosen to illustrate only
because they afford means of simple explanation of my invention.-The chain may
be replaced by wire rope, the worm wheel may conveniently be made as a crown
wheel and inverted with the screw underneath it and the pointer may be fixed on
the frame while on the top of the worm wheel may be figured the position of the
helm, and many other variations may be made without departing from the essential
features of my invention.

page_text: By this arrangement it will be seen that while ample power for steering is
obtained with a small expenditure of force at the steering wheel, any force exerted
in the opposite direction from the rudder on the steering wheel is not only
diminished by the gear, but is so indirectly applied through the worm wheel and
screw as to be practically inoperative to move the wheel, and the gear thereby
becomes self-holding or very nearly so, at the same time by the arrangement of index
the position of the helm is always discoverable without regard to consideration of
the mere turning of the steering wheel.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1st The employment of screw and worm wheel for controlling the helm in ships
so as to make a practically self holding gear, and
2nd The arrangement of index to shew the position of the helm substantially as
described.