Electro-magnetic Compensating Devices for Power Steering Mechanism.
Year: 1899

page_text: Date of Application, 30th June, 1899-Accepted, 19th Aug., 1899
COMPLETE SPECIFICATION.
Electro-magnetic Compensating Devices for Power Steering
Mechanism.
I, JOHN DUNLAP WILLIAMSON, Junior, of Richmond and York Streets, in
the City of Philadelphia, State of Pennsylvania, United States of America,
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 ascertained
in and by the following statement:---
The object of my invention is to provide power steering apparatus with an
electro magnetic compensating device whereby any variation between the actual
position of the rudder and that indicated by the telltale at the steering wheel
will be automatically corrected whenever the rudder is set amidships.
I will describe my invention with reference to the accompanying drawings of
whichi Figs. 1 and 2 represent in side elevation and plan respectively sufficient
of a power operated steering gear to illustrate my invention.
Fig. 3 is an enlarged vertical section of part of the mechanism.
Fig. 4 is a sectional plan view of part of the same; and
Figs. 5 and 6 are diagrams illustrating the electrical connections and parts
operating in conjunction therewith.
The steering wheel (represented at 1 in Fig. 1) is carried by a short horizontal
shaft 2 at the top of a standard 3, which also has bearings for a vertical shaft 4,
the latter being geared by means of suitable bevel wheels 5 and 6 to the steering
wheel shaft 2. The latter shaft is also connected by worm or other gearing to
the spindle of a pointer or telltale 7 at the top of the standard 3, so that as the
steering wheel is turned, to port or starboard, motion in a corresponding direction
is imparted to the said telltale. The lower end of the shaft 4 is coupled to the
upper end of a shaft 8, (Fig. 3) which is adapted to suitable bearings in a frame 9
beneath the platform or deck on which the standard 3 is mounted, and to other
bearings in the said frame is adapted a shaft 10, parallel with the shaft 8 and
situated a short distance laterally therefrom, the said shaft 10 having upon it
a spur wheel 11 and two spur pinions 12 and 13. The spur wheel 11 gears with
a spur pinion 14, fast on the shaft 8, and the pinion 12 gears with a spur
wheel 15 free to turn independently of the shaft 8 and carrying certain electrical
contact plates hereinafter referred to. The pinion 13 gears with a spur wheel 16
which is secured to the hub of a spur pinion 17 (see Fig. 3) likewise free to
turn on the shaft S and engaging with a longitudinal rack 18, which is suitably
guided in a bearing in the frame 9 and is connected to the rod 19 of a piston
contained in a cylinder 20, pipes 21 and 22 providing communication between
the opposite ends of this cylinder and the opposite ends of a cylinder 23, which
contains a piston having a rod 24, connected to a bell crank lever 25, which is
connected to the rod 26, whereby the operation of the rudder moving mechanism
is governed, or the movement of the piston rod 24 may be transmitted directly to
the rudder, of desired, in the smaller class of vessels."
As the steering wheel is turned in one direction or the other therefore the
piston will be caused to traverse back and forth in the cylinder 20, and the

page_text: .
liquid with which the said cylinder is filled will be forced through the pipes 21
and 22 so as to cause movement of the piston in the cylinder 23.
For convenience the cylinder 20 may be called the " transmitting cylinder'
and the cylinder 23 the "controlling cylinder."
The rudder operating mechanism is such that the position of the rudder
corresponds with the position of the piston in the controlling cylinder 23-that
is to say, when the said piston is at one extreme of its movement the rudder is
hard over to starboard, when the piston is at the other extreme of its movement
the rudder is hard over to port, and when the piston is in the intermediate
position or mid-stroke, the rudder is amidships.
These positions of the piston in the cylinder 23 should, when the apparatus is
working properly, be attended by like adjustments of the piston in the trans-
mitting cylinder 20; but it sometimes happens, because of leakage around the
latter piston or from other causes, that the two pistons are not in proper relation
that is to say, when the piston in the controlling cylinder 23 is at mid-stroke
the piston in the transmitting cylinder 20 may be more or less to one side of
mid-stroke, and as the tell-tale on the standard 3 corresponds with the position
of the piston in the cylinder 20 it may, when the helm is actually amidship,
indicate a position of helm more or less to port or starboard. For this reason
it has been proposed to provide the cylinder 20 with pipes 27 and 28, forming
a communication between the opposite ends of the cylinder, the pipes 27 being
provided with check valves 29, and suitable stop valves 30 being placed at
the junction of the pipes 27 and 28 so that these valves can, when necessary,
be opened, so as to provide a free passage of liquid from one end of the cylinder 20
to the other, consequently permitting movement of the piston in said cylinder 20
without any flow of liquid through the pipes 21 and 22 and without any corre-
sponding movement of the piston in the cylinder 23.
Hitherto, in order to detect variance between the true position of the rudder and
its position as indicated by the telltale at the top of the standard 3, it has
been necessary to have in the pilot house a second telltale connected to the rudder
and indicating the true position of the latter, and constant comparison of these
two telltales by the steersman was necessary in order that any variance might
be detected and corrected. Such correction was effected by mechanical means
operated by the steersman, the devices shown in the drawing comprising
plate 31 at the base of the standard 3, the stem of this foot plate being con-
nected to a bell crank lever 32 and the latter by means of a cord or wire 33
being connected to levers 34 whereby the valve 30 could by pressure upon the
plate 31 be opened at the proper times, so as to provide free communication
between the opposite ends of the cylinder 20.
a foot
The above is a description of the present state of the art as known to me,
and my invention consists in providing electro magnetic devices whereby the
compensation of the actuating cylinder 20 may be effected automatically.
These devices I will now proceed to describe.
On the top of the spur wheel 15 is a metallic ring 36, (Fig. 3) suitably insulated
from the said wheel and having throughout about one-half of its extent, a
projecting segment 37 (Fig. 5) and on the underside of the said spur wheel 15
is a ring 38 which is likewise insulated from the wheel and has throughout
about one-half of its extent a projecting segment 39, the two segments 37 and 39
occupying positions on opposite sides of the axial line of the said spur wheel 15,
as shown in the diagram Fig. 5.
Suitably mounted on the frame 9 are upper and lower contacts 40 and 41,
preferably yielding contacts, the upper contact 40 being in line with the upper
contact ring 36 of the spur wheel 15 and the lower contact 41 being in line with
the lower contact ring 38 of the said wheel. At the opposite side of the frame 9
are upper and lower contacts 42 and 43 which are in line, respectively, with the
upper and lower contact segments 37 and 39, the latter being so arranged in
respect to the said contacts 42 and 43 that when the piston occupies a mid-

page_text: position in the cylinder 20 both of the said contacts 42 and 43 will be free from
ngagement with their respective segments, movement of the spur wheel 15
nd its plates in one direction bringing the contact 42 into engagement with the
segment 37 and movement of the spur wheel and its plates in the opposite
lirection bringing the contact 43 into engagement with the segment 39. The
contacts 42 and 43 are connected by means of a wire a to one pole of a battery X
or other generator of electricity, the contacts 40 and 41 being connected by a
wire w to the coils of an electro magnet 44. This electro magnet acts upon an
armature 45 carried by a lever 46 which has a plate 47 acting through the medium
of springs 48 upon the levers 34, which actuate the valves 30, whereby com-
munication is opened between the opposite ends of the cylinder 20. The coils of
the electro magnet 44 are also connected by a wire to a terminal 50, suitably
mounted adjacent to the end of the bell crank lever 25 which is operated by
the piston in the cylinder 23.
Mounted alongside of the terminal 50 is a similar terminal 51, which is con-
nected by means of a wire y to that pole of the battery or other generator of
electricity opposite to the pole which is connected to the contacts 42 and 43.
The end of the bell crank lever 25 is widened and carries a contact with two
lugs 52 and 53, and when the bell crank lever is in the mid-position corre-
sponding with the midship position of the rudder these lugs strike the terminals 50
and 51, respectively, and electrically connect the said terminals. If at this time
the spur wheel 15 is also in midship position, the contacts 42 and 43 will be free
from engagement with the segments 37 and 39, and hence the circuit through
the coils of the electro magnet 44 will be broken and there will be no actuation
of the armature 45 and lever 46 and no opening of the valves 30; but if the
spur wheel 15 occupies a position to one side or the other of the mid-ship line,
implying a departure of the piston in the cylinder 20 from its proper midship
position, one or other of the contacts 42 and 43 will be in engagement with
its respective segment and consequently the electrical circuit through the
magnet 44 will be completed, the said magnet will be energized, the armature 45
attracted, and the valves 30 opened, the said valves remaining open until the
piston in the cylinder 20 and the spur wheel 15 have been restored to mid-
position and the electrical circuit again broken.
To insure proper electrical connections between the contacts 40, 41, 42 and 43
and the rings 36 and 38 and segments 37 and 39 and to prevent more than
one of the contacts 42, 43, from being in engagement with its segment at one time,
I prefer to move the spur wheel 15 positively up or down on the shaft S on each
change in the direction of movement of the steering wheel, and this I accomplish
in the following manner:-
Secured to the shaft 8 are upper and lower cam collars 55 and 56, (Fig. 3)
these collars acting upon the upper and lower ends of a sleeve 57, which surrounds
the shaft 8, is free to turn and to move up and down thereon, and serves as a
bearing for the hub of the spur wheel 15, suitable collars 59 and 60, secured to
the said sleeve above and below the hub of the spur wheel insuring the vertical
movement of the latter with the sleeve. The upper collar 59 is grooved and acted
upon by a segmental friction brake shoe 61, which is hung to a pin 62 at one side
of the shaft 8, and at the other side of the said shaft is acted upon by a spring 63
surrounding a pivoted rod 64, which passes freely through an opening in the free
end of the said brake shoe. (See Fig. 4).
The frictional hold of the brake shoe upon the collar 59 is sufficient to prevent
turning of the sleeve 57 when it is first acted upon by either of the cam collars
55 or 56, hence the first action of either of the said collars is to force the sleeve
upward or downward on the shaft S, so as to carry the spur wheel 15 up or down
with it until the contact plates on the said wheel are pressed firmly against the
5 upper or lower contacts mounted upon the fixed frame, further rotative movement
of the shaft 8 being then imparted to the sleeve 57 the brake shoe 61 slipping
over the collar 59 until the direction of motion is reversed. The cam collars

page_text: are such that the wheel 15 will be pressed upward when moving in the direction
of the arrow, Fig. 5, and downward when moving in the reverse direction. Hence
each segment will be pressed against its contact when the wheel is moving
toward the midship position with respect to that segment and each segment may
therefore extend up close to the midship line.
While therefore I prefer to use mechanism for moving the spur wheel 15
longitudinally on the shaft S on each reversal of the direction of movement of
the steering wheel, the same is not absolutely essential to the proper carrying out
of my invention and may be omitted if desired, the contacts 42 and 43 having
resilient spring-backings and the said contacts or the ends of the segments 37
and 39 being bevelled, so that the contacts will easily ride onto the segments as
the latter are moved beneath the same. In this case, however, the ends of the
segments cannot approach closely to the midship line of the wheel, as a sufficient
space on each side of the midship line will have to be left to insure the breaking
of the current until the contact of the lever 25 is moved away from the terminals
50 and 51, hence the regulation cannot be so accurate as when the wheel 15 moves
longitudinally on the shaft S.
Various means other than the valves 30 and valve levers 34 may be employed
for opening communication between the opposite ends of the cylinder 20. "In
fact, the mechanical details of the apparatus may be varied in many ways without
departing from the essential features of my invention so long as electro magnetic
compensating devices are employed which rely for their action upon want of
correlation between the piston operated by the steering wheel and that which
operates the rudder moving devices.
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 :-
-
1. Power steering apparatus in which are combined a transmitting cylinder
having a piston operated by the steering wheel, a controlling cylinder having a
piston governing the operation of the rudder moving devices, means whereby
movement of the piston in the transmitting cylinder is caused to impart move-
ment to the piston in the controlling cylinder electro magnetically operated
mechanism whereby movement of the piston in the transmitting cylinder is
permitted without corresponding movement of the piston in the controlling
cylinder, and connections whereby the said electro magnetic devices are rendered
operative by want of correlation in the positions of the two pistons, substantially
as hereinbefore described.
2. Power actuated steering apparatus having in combination a transmitting
cylinder with piston actuated by the steering wheel, a controlling cylinder with
piston governing the rudder moving devices, means whereby movement of the
piston in the transmitting cylinder causes movement of the piston in the con-
trolling cylinder, electro magnetic devices for permitting movement of the
piston in the transmitting cylinder without movement of the piston in the con-
trolling cylinder, and two circuit closers, one operated by the piston of the
controlling cylinder, and the other by the steering wheel substantially as herein-
before described.
3. Power actuated steering apparatus having in combination a transmitting
cylinder with piston actuated by the steering wheel, a controlling cylinder with
piston governing the rudder moving devices, means whereby movement of the
piston in the transmitting cylinder causes movement of the piston in the con-
trolling cylinder, electro magnetic devices for permitting movement of the
piston in the transmitting cylinder without movement of the piston in the
controlling cylinder, and two circuit closers, one operated by the piston of the
controlling cylinder and the other by the steering wheel, the latter circuit
closer having two contacts, one operative when the rudder moves to star-board,

page_text: and the other operative when the rudder moves to port, substantially as herein-
before described.
4. Power actuated steering apparatus having in combination a transmitting
cylinder with piston actuated by the steering wheel, a controlling cylinder with
piston governing the rudder moving devices, means whereby movement of the
piston in the transmitting cylinder causes movement of the piston in the con-
trolling cylinder, electro-magnetic devices for permitting movement of the piston
in the transmitting cylinder without movement of the piston in the con-
trolling cylinder, and two circuit closers, one operated by the piston of the con-
trolling cylinder and the other by the steering wheel, the latter circuit closer
having two contacts, one operative when the rudder moves to star-board and the
other operative when the rudder moves to port, and being combined with means
whereby the contacts are alternately thrown into and out of action by the port
and starboard movements of the steering wheel, substantially as hereinbefore
described.
.5. The combination in power steering mechanism, of a wheel having upper
ad lower contacts with projecting segments on opposite sides of the axial line
the wheel, fixed contacts forming part of an electric circuit, one adapted to
ngage with one segment and the other with the opposite segment, and means
for moving the said contact carrying wheel in unison with the movements of
the steering wheel, substantially as hereinbefore described.
6. The combination in power steering mechanism, of a wheel having contact
plates on opposite sides, terminals disposed on opposite sides of the wheel, a
shaft in operative connection with the steering wheel, and cam collars on said
shafts whereby the contact carrying wheel will be moved longitudinally thereon
whenever the direction of movement of the steering wheel is reversed sub-
stantially as herein before described.
7. The combination in power steering mechanism, of a wheel having contact
plates on opposite sides of the same, contacts disposed on opposite sides of the
wheel, a shaft operatively connected with the steering wheel, a sleeve carrying
the contact wheel and free to turn and to move longitudinally on the said shaft
cam collars for effecting such longitudinal movement, and a friction brake for
preventing rotation of the sleeve during the first action of the cam collars;
substantially as hereinbefore described.
Tatod this 30th day of T. 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.