Communications: electrical – Vehicle position indication
Reexamination Certificate
1999-11-08
2001-10-16
Wu, Daniel J. (Department: 2632)
Communications: electrical
Vehicle position indication
C701S224000, C701S301000, C033S351000
Reexamination Certificate
active
06304195
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device to alter the path of a boat having an automatic pilot with a magnetic compass that is activated upon the reception of an alarm signal and comprises means to fix the compass of the automatic pilot on a fictitious North.
There is a security device of the above type already known from the international patent application WO 94/06679. This security device is now being commercially distributed under the reference ADSM “Sea Rescue Apparatus” by the firm ADSM Inc., Miami, Fla. It requires no physical connection to the automatic pilot and may be installed on every type of boat.
As can be seen in
FIG. 1
, the safety device
1
that is commercially distributed has at least one transmitter
2
carried by the navigator, sending a radio signal, an on-board receiver
3
, a coil B in the vicinity of the magnetic compass
5
of the automatic pilot
6
and a circuit
7
for the control of the coil. The control circuit
7
receives a list signal Si and a course signal Sr at input. The course signal Sr is delivered by a selector switch
8
with four positions N (North), S (South), W (West) and E (East). The list signal Si is delivered by a tilt indicator
9
provided with an integrator circuit
10
and represents the mean direction of listing of the boat, portside (wind on starboard) or starboard (wind on portside).
When the receiver
3
no longer receives the radio signal, it activates an alarm signal Sa that activates the control circuit
7
and locks the listing signal Si to the output of the tilt indicator
9
. The circuit
7
then sends an excitation voltage V (or a current) into the coil so as to create a fictitious North which fixes the compass
5
in a specified position. By reaction, the automatic pilot
6
makes the boat turn so as to retrieve the lost course, in such a way that the boat keeps going around in circles so long as the alarm signal Sa is maintained.
Table 1 here below gives a more detailed description of the working of the device
1
By convention, the coil is placed to the left of the compass, namely on the portside. The direction of movement SM of the boat is identified by an arrow in FIG.
1
. Depending on the sign of the excitation voltage V, the coil creates a fictitious North NF1 on portside or a fictitious South on portside equivalent to a fictitious North NF2 on starboard side.
TABLE 1
Course
Fictitious
(Sr)
Listing (Si)
North
Turning
North (N)
starboard
NF1
portside
portside
NF2
starboard
South (S)
starboard
NF2
portside
portside
NF1
starboard
East (E)
—
NF2
variable
West (W)
—
NF1
variable
Since it is necessary to obtain a minimum rudder angle of 30° in an emergency, the fictitious North dictated by the coil is imperatively at starboard (NF2) when the boat is heading East. Indeed, in this case, the magnetic North of the compass is oriented towards the coil as shown in
FIG. 1
so that a portside fictitious North (NF1) would not make the compass rotate. For the same reason, the fictitious North is imperatively oriented to the portside (NF1) when the boat is heading substantially towards the West. In both these directions, the list signal Si is not taken into account as can be seen in Table 1.
In the case of a sail boat, when there are strong winds, it is desirable however, in order to prevent the breaking of the boom by jibing, that the boat should not veer downwind. The boat should therefore preferably veer against the wind.
This problem, identified in the international patent application WO 94/06679 has not been resolved to date except when the boat is heading substantially Northwards or substantially Southwards. On the contrary, when the boat is heading substantially Eastwards or substantially Westwards (with the selector switch in the East or West position), the sense of the turn made by the boat when the alarm signal Sa is activated is not controlled. Depending on the exact position of the compass when the safety device is activated, the boat may turn to starboard or port when the selector switch
8
is in the East or West position.
The present invention seeks especially to overcome this drawback.
More particularly, a general goal of the present invention is to provide for a device to alter the course of a boat that takes account of the direction of the list whatever the course being followed.
This goal is achieved by means of a device to alter the course of a boat of the type described here above, wherein the means to fix the compass comprise two coils positioned in the vicinity of the compass along complementary axes, means to excite each of the coils and means to distribute the excitation of the coils as a function of a course signal and a boat list signal, arranged to take the compass into a fixed position in making it turn preferably counter-clockwise when the listing is to starboard and clockwise when the listing is to port.
Preferably, the coils are arranged so as to make the compass rotate by an angle at least equal to 45° whatever the course taken by the boat. For example, the device may include two coils positioned in substantially orthogonal axes.
According to one embodiment, the means for distributing the excitation of the coils comprise means for selecting either one of the coils as a function of the course signal, and means for delivering a signal for the excitation of the selected coil, the polarity of which is a function of the course signal or of the listing signal.
According to one embodiment, the means for distributing the excitation of the coils comprise means for the simultaneous application, to each of the coils, of an excitation signal whose value and polarity are determined as a function of the course signal and of the list signal.
Advantageously, the means for simultaneously applying an excitation signal to each of the coils comprise a memory receiving the course signal and the listing signal at its address inputs.
According to one embodiment, the course signal is delivered by a selector switch or a manual selector. The course signal may be encoded in the form of a binary word.
According to one embodiment, the device of the invention comprises an automatic detector of the terrestrial magnetic North, delivering a divergence signal representing the angle between the terrestrial magnetic North and a reference axis of the boat, and a computation means receiving the list signal and the divergence signal at input, arranged to deliver weighted signals for the excitation of each of the coils.
The present invention also relates to an anticollision system for a boat equipped with an automatic pilot with magnetic compass, comprising a device for the detection of obstacles delivering an alarm signal when an obstacle is detected, and a device to alter the course of the boat in accordance with the present invention, controlled by the alarm signal delivered by the obstacle detection device.
REFERENCES:
patent: 3888201 (1975-06-01), Zuvela
patent: 4179741 (1979-12-01), Rossani
patent: 4336596 (1982-06-01), Martin
patent: 4725957 (1988-02-01), Alberter et al.
patent: 4791729 (1988-12-01), Suda
patent: 5287295 (1994-02-01), Ives et al.
patent: 5313397 (1994-05-01), Singh et al.
patent: 5357437 (1994-10-01), Polvani
patent: 5440303 (1995-08-01), Kinoshita
patent: 2 643 607 (1991-08-01), None
patent: 2 695 904 (1994-03-01), None
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
Tweel , Jr. John
Wu Daniel J.
LandOfFree
Device for altering the course of a boat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for altering the course of a boat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for altering the course of a boat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2557983