SYSTEME DE GUIDAGE

STEERING SYSTEM

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
A steering system comprising in combination at least two steering
directing members, e.g. hand wheels or the like, each of which is connected
via a flexible, rotatable and torque transferring shaft to a mechanism
capable of converting a rotary motion into a linear movement. This mech-
anism can be a ball-nut mechanism. There is also a device arranged for
optional disconnecting of any one of said shafts from said converting device.
The conversion device incorporates two rotatable wheels drivin by a shaft
each. These wheels cooperate for transferring a torque and are optionally
disconnectable from a wheel arranged on a rotatable element.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A steering system comprising at least two steering directing
members, a device for conversion of torsional movement into a linear move-
ment, which linear movement during operation of the system is used for steer-
ing purposes, two rotatable and torque transmitting shafts with each shaft
connecting and transferring movement from one of said directing members to
said conversion device, and means for optional disconnection of either one
of the shafts from said device.
2. A steering system according to claim 1, wherein the conversion
device incorporates a number of rotatable wheels driven by a shaft each,
which wheels cooperate for transferring a torque and being optionally dis-
connectable from a wheel arranged on a rotatable element, the rotation of
which inside the device is converted into a linear movement performed by a
member cooperating with said rotatable element.
3. A steering system according to claim 2, wherein at least one of
the wheels driven by the shafts is always in engagement with the wheel
arranged on the rotatable element.
4. A steering system according to claim 3, wherein the afore-
mentioned wheels are cog wheels and the wheel arranged on the rotatable
element is axially displaceable for optional cooperation with one of the
wheels driven by the shafts, which last mentioned wheels are arranged with
a mutual axial space which is less than the axial extension of the wheel
arranged on the rotatable element.
5. A steering system according to any one of claims 1 to 3 wherein
a particular motor is disengageably connected to the device for conversion

of the torsional movement to a linear movement for the driving of the
device.

Description

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The present invention refers to a steering system incorporating
a steering directing member, the movement of which is transferred via a
rotatable and torque transmitting shaft to a device for conversion of a
torsional movement into a linear movement. The latter movement is used for
~teering purposes.
Such steering systems are known ~or use, e.g. in boats, whereby
the steering directing member is a steering wheel and the linear movement is
used for actuation of a helm or the like. The device for converting a
tor~ional movement into a linear vement is preferably a ball screw cylin-
der. It is also known to connect a servo device to such a ~teering system,
whereby this servo device can be used as autopilot steering or for obtaining
a dual control. At such a d~ control the capacity of one of the steering
positions as to swiftness and exactness i8 however depending on the capacity
of the servo device in these respects. It is in certain connections deslr-
able or even a dem~nd that it shall be possible to actuate the two dual con-
trol steering positions fully manually ~nd mechanically to ascertain that the
steering characteristics in both cases are equal and lt i8 thereby impossible
to use a dual control which uses the servo device as its only torque generat-
ing member in one steerine position.
The purpose of the present invention is to produce a possibility to
connect a fully mechanically and manually actuable dual control to a steering
system of the kind mentioned in the preamble in a simple manner
According to the invention, a steering system comprises at least
two steering directing members, a device for conversion of torsional move-
ment into a linear movement, which linear movement during operat~on of the
system i6 used for steerin~ purposes, two rotatable and tor~ue transmitting
shafts ~ith each shaft connecting and transferring movement from one of said
directing members to said conversion device, and means for optional discon-
-- 1 --

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nection of either one of the shafts from said device.
The steering system described herein has a compact design which
only requires small space and which can be easily adapted for cooperation
with components and accessories of different types. It is furthermore easy
to operate, it has a safe operation and it can be manufactured at a com-
paratively low cost.
A preferred embodiment of the invention will hereinafter be further
described with reference to the accompanyine drawings.
Figure 1 shows a perspective view of essentail details in the
system according to an embodiment of the invention, Figure 2 is a longitudi-
nal section through the details shown in figure 1, and Figure 3 shows a sec-
tion along line III - III in figure 2.
The steering system according to the invention incorporates two
steering directing members, e.g. two steering wheels ~not shown) located at
different positions in a motor boat. The motions of the steering wheels are
transferred ~ia two preferably flexible, rotatable and torque transferring
shafts to a device for transforming the torsional mo~ement into a linear
movement. This device is shown in figure 1 and it incorporates a housing 1,
the contents of ~hich are further described herebelow and which housing has
two connections 2, 3 for the not sho~n flexible shafts. The connections
incorporate in the embodiment shown non~circular shaft ~ournals intended to
be pushed into a corresponding aperture in each one of the ends of the flex-
ible, rotatable shafts and sleeve nuts intended for tightening against
threaded portions at the end of the non-rotatable casing of each shaft.
The portion of the device which moves linearly and is used for
steering i5 designated 4. This part can for instance be connected to a helm
or the like, whereby the housing 1 is prefera~ly fixed to the hull of the
boat preferably in connection to the helm

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As can be best seen from figures 2 and 3 the housing 1 has a casing
5 inside which is arranged three cog wheels 6, 7, 8 with straight cogs. The
wheel 6 i8 non-rotatably connected to a shaft 9, which is rotatably sup-
ported in the casing and which is rotated from one of the steering wheels by
means of the flexible torque transferring shaft which is connected to the
connection 2. The wheel 7 is in a corresponding manner arranged on a shaft
10, which cooperates with the connection 3 and the flexible shaft from the
other one of the steering wheels. The shafts 9 and 10 are parallel and the
cog wheels 6 and 7 are axially displaceable relative to each other. The cog
wheel 8 is non-rotatably but axially displaceably arrangea on a shaft 11,
e.g. by means of splines. The shaft 11 is at one of its ends provided with
a shaft ~ournal 12 covered by a cover 13. The opposite end of the shaft 11
i8 non-rotatably connected to a rotatable screw or nut in a ball nut cylin-
der, whereby the nut or the screw at rotatlon of the shaft will be linearly
displaced in the ball screw cylinder in a manner known per se. The shaft
~ournal 12 can via a suitable coupling e.g. a magnetic coupling or a free
wheel coupling be connected for instance to a servo motor or a motor for
autopilot steering. The cover 13 can thereby be substituted for a motor or
a coupling attachment which can be fixed in the sa~e manner as the cover.
The displacement of the cog wheel 8 for its intermeshing with one of the cog
wheels 6 or 7 is carried through by means of a control lever 14, which is
connected at one hand to a pull wire 15, which in turn is connected to a not
shown control lever and on the other hand to a pressure spring 16, which
presses the arm 14 in a direction opposite the pullinK directiGn of the wire
15. The cog wheel 8 is provided with an annular groove 17, wherein is
introduced the outer race ring of a ball bearing 18 which is arranged on the
arm 1~. At displace~ent of the arm 1~ and thereby the ~earing 18 to the
left or to the ri~ht (figure 2) the cog wheel 8 is thus ~.aking the same

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movement. The outer race ring of the bearing 18 rotates during operation due
to its friction against the groove 17. In the position shown in figure 2,
where the arm 14 is displaced to the right, wheels 6 and 8 are interconnected
wherea wheel 7 i6 disengaged. When the arm 14 is displaced to the left the
groo~e 17 will occupy the position shown with dash and dot lines and the
wheels 7 and 8 are thereby interconnected whereas wheel 6 is disengaged. In
order to ascertain that the steering always can take place with at least one
of the steering wheels the axial extension of the cog wheel 8 is bigger than
the mutual axial space between wheels 6 and 7, whereby all three wheels 6,
~ and 8 are interconnected when the arm 14 is located in its intermediate
position.
The invention is not limited to the embodiment described here-
above. It is for instance possible tbat other elements than the ball nut
device can be used for transforming the torsional movement into a linear
movement, e.g. by gear racks. The operation of the cog wheel 8 can for
instance be carried through with hydraulic or electromagnetic members or with
a push/pull transferring rod or cable. It i8 possible to use more than two
steering directing members ~n the system, whereby more cog wheels correspond-
ing to wheels 6 and 7 are arranged to be connectable to wheel 8. A servo
motor or a motor for autopilot steering can if desired be connected to the
steering system via cog wheels corresponding to wheels 6 and 7 instead of
via the shaft ~ournal 12. The arrangement according to the shown embodiment
with the wire 15 and the shafts 9, 10, 11, 12 arranged in the same plane has
however the ad~antage th~t the housing 1 can be made slender and compact
which gives a high degree of freedom at mounting in narrow spaces.