Improvements in Steam Steering Gear.
Year: 1889

page_text: 'Date of Application, 22nd Mar., 1889
Complete Specification Left, 20th Dec., 1889-Accepted, 25th Jan., 1890
PROVISIONAL SPECIFICATION.
Improvements in Steam Steering Gear.
I, WILLIAM HORATIO HARFIELD, of Mansion House Buildings, in the city of
London, Mechanical Engineer, do hereby declare the nature of this invention to
be as follows:-
My invention relates to improvements in actuating the valve gear of engines used
for steering ships and more particularly applies to that kind of gear where the direction
of motion of the said engines is changed or reversed by an auxiliary valve which
transposes alternately the pressure and exhaust sides of the ordinary slide valves.
This auxiliary valve (usually termed a reversing valve" but which also acts as a
starting and stop valve) has to be controlled by the steersman so that the engines
will follow concurrently the motions of the steering wheel. Now in order to effect
this concurrent motion more efficiently than hitherto I connect to the rod actuating
tho reversing valve a small worm wheel which has two worms or screws gearing into
it, one on either side. One of these worms is in connection with and turned by
shaft driven by the engine. The other worm is in connection with and turned by
the steering wheel. If now the steering wheel be turned then the worm connected
with it revolves the worm wheel, rolling it along the other worm as upon a rack and
causes the valve rod to be moved, thereby opening the valve and starting the engine
which immediately revolves the other worm and (as 1 so arrange it) draws or works
back the worm wheel in the contrary direction tending to close the valve.
Dated the 22nd day of Norah 1880
aL
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Steam Steering Gear.
I, WILLIAM HORATIO HARFIELD, of Mansion House Buildings, in the city of
London, Mechanical Engineer, 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 :-
My invention relates to improvements in actuating the valve gear of engines used
for steering ships, and more particularly applies to that kind of gear where the direction
of motion of the said engines is changed or reversed by an auxiliary valve which
transposes alternately the pressure and exhaust sides of the ordinary slide valves.
This auxiliary valve (usually termed a "reversing valve" but which also acts as a
starting and stop valve) has to be controlled by the steersman so that the engines
will follow concurrently the motions of the steering wheel. Now in order to effect
this concurrent motion more efficiently than hitherto I connect to the rod actuating
the reversing valve a small worm wheel which has two worms or screws gearing into
it, one on either side. One of these worms is in connection with and turned by a
shaft driven by the engine. The other worm is in connection with and turned by
the steering wheel. If now the steering wheel be turned then the worm connected
with it revolves the worm wheel, rolling it along the other worm as upon a rack,
and causes the valve rod to be moved, thereby opening the valve and starting the
engine which immediately revolves the other worin and (as I so arrange it) draws or
works back the worm wheel in the contrary direction tending to close the valve.
To enable my invention to be fully understood I will describe the same with
reference to the accompanying drawing, which is a plan partly in section of a steering
engine provided with my improvements.

page_text: a, a are the engine cylinders each of which is provided with a piston band with a
valve-chest c containing a slide valve d, and e is the crank shaft, all of which parts
are of ordinary construction and form no part of my invention.
g
is the auxiliary or reversing valve which, as shown, is of cylindrical form. This
valve is located in a chainberg between the valve-chests e, c and is supplied with
steam from the boiler through the orifices h, h! i, i, j, j are two pairs of passages for
establishing communication between the chamber and the valve chests c, c, which
passages are so placed that they can be opened or closed simultaneously by the valve/
and that they will lead to the outer and inner sides of the valves d, d respectively. The
valve is shown in the mid or closed position, but either the passages i orj can be
opened by moving the valve to the right or left hand. When one set of passages,
say, is open steam will pass to the engine slide valves while the other set of
passages will serve for the return or exhaust and vice versa when the passages j, i
are opened.
m,
The rod of the valve is connected to a bar which carries, upon a pin or stud
a small worm wheel n. With this wheel n, but upon opposite sides thereof, gear
two screws or worms o, p which are parallel with each other and carried in two cross
pieces mounted upon the bed plate of the engine and serving as a guide or support
for the bar. The worm o is geared with the crank shaft e of the engine through
the medium of the worm wheel and the worm s while the worm p is rotated by the
steering wheel which may be placed in any position in the ship and connected with
the said worm by shafting.
?"
The operation of my improved apparatus is as follows:-Suppose that the steering
wheel t is turned in the direction indicated by the arrows 1, 1, the worm > then acts
upon the wheel n turning it upon its stud and rolling it along the other worm o, thus
drawing the bar and valve f forwards, or towards the right. This at once opens the
passages i, i so that steam is admitted to the valve-chests and cylinders and the engine
starts. The worms and worm wheel then rotate the worm o in the direction, shown
by the arrow 2, this direction being contrary to and counteracting that of the worm p
thereby tending to move the valve f back again to close the ports and stop the engine,
which it will do should the steersman cease to move the wheel t. The engine will
always work concurrently with all the steersman's movements, that is to say, it will
run fast when the wheel t is moved quickly, and slowly if the wheel is moved slowly,
because the engine works back the valve until the rates of motion of the worms o
and p correspond. For instance, should the worm p move faster than the worm o then
the passages i, i are opened to a greater extent than otherwise and the engine getting
more steam turns the worn o at a greater rate until it corresponds with the worm p,
when the valve ceases to open the passages i, i further. Or, should the worm p be
moved more slowly, then the worin o outruns the worm p and forces back the valve,
thereby reducing the opening of the passages i, i and consequently slowing down the
engine until the worms are again revolving at equal speeds. Again, if the steering
wheel t be turned in the opposite direction to that indicated by the arrows, then the
valvequickly closes the passages i, i owing to the combined action of both worms
in one direction, and then opens the passages j, j to the steam, the passages i, i serving
for the exhaust. The engine then commences running in the contrary direction to
that previously described and it will act in the reverse manner in accordance with
the movements of the steering wheel.
Although I have described my improvements as applied to engines operated by
steam it is to be understood that they are also applicable to engines operated by air;
water or other fluid pressure.
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
claim is
(1) In engines for use in steering ships, the combination of two worms or screws
with a worm wheel for exerting a counteracting effect upon a valve which controls the
admission of steam to the cylinders, substantially as described..

page_text: (2) The manufacture and use of steering gear the engines of which are provided
with the improved mechanism herein before described and illustrated in the accom-
panying drawing.
Dated the 20th day of December 1889.
W. H. HARFIELD.
G. F. Redfern & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.