Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02073863 2001-04-30
TOW VEHICLE ALIGNMENT METHOD AND APPARATUS
FIELD OF THE INVENTION
The present invention relates to a novel method
and apparatus for monitoring towed vehicles. More particu-
larly, the method pertains to one or more markers which are
mounted on the towed vehicle and one or more monitors which
are mounted in alignment on the towing vehicle to thereby
enable the relative displacement of each vehicle to be
monitored through one or more rear view mirrors.
BACKGROUND OF THE INVENTION
There are many types of towed vehicles, such as
trailers and the like, which are not visible in one or more
rear view mirrors mounted on the towing vehicle. The
problem is particularly acute with wide recreation vehicles
or motor homes. Since a narrow vehicle being towed behind
a motor home is not visible t~-the driver of the motor home
in the sight lines of any of his side mounted rear view
mirrors, or the centre mounted rear view mirror, if appli-
cable, the driver has no idea whether the vehicle is
behaving properly.
There are many things which can go wrong with a
towed vehicle. The hitch can fail or come loose. One of
the tires can become flat. A wheel bearing can seize. An
axle can bend or fail. Some part of the suspension can
fail. The towed vehicle can be struck from the rear.
Since the motor home or towing vehicle is heavy and has a
lot of momentum, it is very difficult for the driver of the
towing vehicle to sense through the feel in the steering
wheel that something is wrong with the towed vehicle,
particularly if it cannot be seen.
In the absence of a timely warning to the driver
of the towing vehicle, hitch failure may result in the loss
of the towed vehicle or the development of various hazard-
CA 02073863 2001-04-30
- 2 -
ous conditions. Without the generation of an early warning
to the driver when tire, bearing, axle, or suspension
problems begin to develop, the driver of the towing vehicle
will carry on until a serious problem has occurred such as
having the trailer dragged behind the towing vehicle
thereby resulting in damage or destruction of the towed
vehicle. The heat generated by dragging a trailer over a
prolonged distance, with a low or flat tire or with metal
in contact with pavement, presents ~a danger of fire to
inflammable components which may then consume the towed
vehicle when the towing vehicle is eventually stopped.
Minor rear end impact is difficult to detect, yet it can be
sufficient to damage a towed vehicle without alerting the
driver of the tow vehicle.
When the towed vehicle is or is not visible to
the driver of the towing vehicle, it is still a problem
with long towed vehicles such as trailers to determine in
the rear view mirror the precise position of the rear end
of the trailer. When the markers are mounted at the
extreme side rear of the towed vehicle, the markers ident-
ify the rear point, giving the driver increased judgement
for safer lane changes, maneuvering through tight spots,
parking and backing up. For example, with-a boat behind a
motor home, it is difficult for the driver to back the boat
or boat trailer to the water without jack-knifing. The
markers mounted on each side of the boat trailer duplicate
the movement or location of the boat and assist in backing
up.
The foregoing problems have recently been ad-
dressed by "high tech" solutions, such as mounting a video
camera on the back of the towing vehicle with the camera
focused upon the towed vehicle. The video camera solution
is expensive and does not provide a complete solution
because it does not give an early warning of developing
problems. The camera is unavoidably mounted on the top of
CA 02073863 2001-04-30
- 3 -
the towing vehicle and is focused on the top of the towed
vehicle. If the video camera is mounted on either side, it
is vulnerable to damage by vandalism or colliding with a
stationary object. A problem manifesting itself in a
change in the positioning of the towed vehicle must be well
advanced in order for the problem to be visible in the
video camera from that vantage point.
U.S. Patent No. 4,257,706, Smith, issued March
24, 1981, discloses motor vehicle back-up limit gauging
methods and apparatus which include a pair of line-of-
sight indicators affixed to the left side of the vehicle.
They are placed in such positions that the driver of the
vehicle when seated in the driving position may establish
a line-of-sight by aligning these indicators through the
existing rear view mirror. He or she may then back the
vehicle to a safe distance from a building wall or other
marker by halting the backward progress of the vehicle when
the aligned indicators coincide with the ground line of the
wall, or with the marker. There is no teaching of a marker
and monitor system which relates the position or condition
of the towing vehicle with the towed vehicle.
The invention disclosed in U.S. Patent No.
2,984,011, Hamilton, issued May 16, 1961, relates to a
towed vehicle hitching guide which may be used in conjunc-
tion with a rear view mirror on the driver's side of the
vehicle to enable the driver to properly steer the towing
vehicle while backing it up to line up the hitching connec-
tion on the towing vehicle with the corresponding connec-
tion on the towed vehicle. This system does not enable the
driver to monitor the position or condition of the trailer.
SUMMARY OF THE INVENTION
The present invention provides a method for
monitoring the position or location of towed vehicles, such
CA 02073863 2001-04-30
- 4 -
as trailers and the like, which are visible or not visible
in one or more side mounted rear view mirrors of a towing
vehicle. The method comprises, firstly, attaching one or
more markers to a towed vehicle such that the marker ( s ) are
visible to the driver on at least one side of the towing
vehicle to which the towed vehicle is coupled. The mar-
ker s) can have enlarged ends to thereby improve the
visibility of the markers) in the rear view mirrors of the
towing vehicle. Secondly, one or more reference markers
are attached to one or both sides of the towing vehicle in
a position such that the reference markers are in linear
alignment with the markers) when viewed from one or more
side mounted rear view mirrors of the towing vehicle. When
the markers) cease to be in linear alignment with the
reference markers) during driving, the driver of the
towing vehicle knows there has been an alteration in the
relative position of the towed vehicle and the towing
vehicle thereby indicating a potential problem which
requires stoppage of the vehicles.
The invention provides a method of monitoring the
relative orientation of a towed vehicle coupled to a towing
vehicle equipped with one or more side mounted rear view
mirrors which comprises: (a) attaching a reference marker
to the side of the towed vehicle, the marker being visible
in the rear view mirror of the towing vehicle; (b) attach-
ing a monitor to the side of the towing vehicle in a
position that the monitor intersects the line of sight
between the marker and the rear view mirror.
In another aspect, the invention includes an
apparatus which can be used in accordance with the teach-
ings of the described method. The marker mounted on the
towed vehicle can be a tubular telescopic body having a
first end which attaches to the towed vehicle. The first
end can be secured to the towed vehicle by a spring to
enable the telescopic body to pivot relative to the towed
CA 02073863 2001-04-30
- 5 -
vehicle. The second end remote from the towed vehicle can
be enlarged to enhance visibility. The second end can be
coated with a fluorescent or reflective material or can be
illuminated.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will
become more apparent from the following description in
which reference is made to the appended drawings, wherein:
Figure 1 represents a side elevation of a motor
home towing an automobile with the front wheels mounted on
a towed trailer.
Figure 2 represents a top view of the two ve-
hicles illustrated in Figure 1.
Figure 3 represents a driver's view through a
rear view mirror side mounted on the motor home.
Figure 4 represents a side elevation of the
vehicles illustrated in Figure 1, except that the vehicle
being towed has a flat tire.
Figure 5 represents a driver's view through a
rear view mirror side mounted on the towing vehicle when
the trailer has a flat tire as illustrated in Figure 4.
Figure 6 represents a side elevation of a single
axle vehicle being towed by a motor home.
Figure 7 represents a side elevation of the
vehicles illustrated in Figure 6, except that the hitch of
the vehicle being towed has disconnected.
CA 02073863 2001-04-30
- 6 -
Figure 8 represents a top view of the two ve-
hicles illustrated in Figure 7.
Figure 9 represents a side elevation of the same
vehicles illustrated in Figure l, except that the front
wheels of the vehicle being towed have moved partially off
the trailer.
Figure 10 represents a top view of the two
vehicles illustrated in Figure 9.
Figure 11 represents a driver's view through a
rear view mirror mounted on the side of the towing vehicle
illustrated in Figures 7 or 9.
Figure 12 represents a perspective view of a
specific embodiment of a marker mounted on a trailer.
Figure 13 represents a top view of a specific
method of illuminating the marker apparatus illustrated in
Figure 12 by the tail lights of the towing vehicle for
night operation.
Figure 14 represents a detailed view of a tail
light adapted to illuminate the marker illustrated in
Figure 13.
DETAILED DESCRIPTION OF SPECIFIC
EMBODIMENTS OF THE INVENTION
Specific embodiments of the method and apparatus
of the invention will now be described in detail with
reference to Figures 1 through 14. The basic concept of
the described method is that a potential problem with a
vehicle which is being towed, or the towing vehicle itself,
will manifest itself by an alteration in the alignment of
one or more markers mounted on the towed vehicle and one or
CA 02073863 2001-04-30
_ 7 _
more reference markers mounted on the towing vehicle. If
the towing vehicle develops a problem such as a leaking
tire, its position relative to the towed vehicle will
become altered. If a problem develops with the towed
vehicle, for example, a disconnected hitch, its position
relative to the towing vehicle will also become altered.
The method of the invention therefore enables the relative
positioning of both the towing vehicle and the towed
vehicle to be monitored. The method is particularly
adapted to monitor towed vehicles, such as trailers and the
like, which are not visible in a side mounted rear view
mirror of a tow vehicle.
The method of the invention in a specific version
comprises the following steps, as illustrated with refer-
ence to Figures 1 and 2. Firstly, a pair of marker rods 12
is attached to each side of a towed vehicle 14. The rods
12 are preferably attached adjacent each axle 16 of the
towed vehicle. In Figures 1 and 2, two rods 12 are used,
whereas with the single axis trailer illustrated in Figure
6, only one rod is used. However, only one pair of rods 12
can be used in the embodiment shown in Figures 1 and 2 if
desired. The pair of rods 12 are arranged to extend
laterally from each side of the towed trailer 14 until they
are visible beyond each side 18 of the towing vehicle 20 to
which towed vehicle 14 is coupled. The unattached end 22
of each of the rods 12 are enlarged so as to be clearly
visible in the side mounted rear view mirrors 26 of the
motor home 20. Secondly, a pair of reference markers 24
are attached to each side 18 of the towing vehicle 20 in a
position such that each reference marker 24, when seen in
the side mounted rear view mirror 26 from the driver's
seat, is in linear alignment with the respective enlarged
unattached ends 22 of the respective rods 12. The desired
linear alignment as viewed by the driver in the rear view
mirror 26 is illustrated in Figure 3. As can be seen, the
reference marker 24 virtually covers the enlarged end 22.
CA 02073863 2001-04-30
If the enlarged attached end 22 of either rod 12 ceases to
be in linear alignment with the reference marker 24 during
highway driving, the misalignment serves as a signal to the
driver of the tow vehicle 20 that there has been an alter-
s ation in the respective positioning of the towed vehicle 14
and the towing vehicle 20 thereby indicating a potential
problem which probably requires stoppage of the vehicles 20
and 14.
A typical linear misalignment of the marker 12
and reference marker 24 is illustrated in Figure 4 with
respect to a flat tire on the towed vehicle 14. When a
flat tire occurs, the towed vehicle 14 becomes lower on
that side and the driver of the tow vehicle 20 sees in side
mounted rear view mirror 26 the marker-reference marker
misalignment as illustrated in Figure 5. The marker 22 has
dropped out of alignment with reference marker 24 and the
driver then knows that a problem has occurred.
A further example of linear misalignment is
illustrated in Figures 7 and 8, where a single axle trailer
14 as illustrated in Figure 6 has developed a disconnection
at the hitch. In Figure 6, the reference marker 24 and the
marker 22 are in visual alignment when seen from rear view
mirror 26. However, when the hitch 25 becomes disconnected
as illustrated in Figures 7 and 8, misalignment occurs.
This results in towed vehicle 14 not travelling snugly and
securely behind tow vehicle 20. The towed vehicle 14 in
such a case usually begins to whip or swing back and forth
from side to side. In the absence of the apparatus and
method of the invention, the lateral movement of towed
vehicle 14 would not be visible to the drive of tow vehicle
20 until the trailer "jack-knifed" which is a dangerous
condition because the towing vehicle 20 may be thrown out
of control. With the apparatus and method of the inven-
tion, the driver of towing vehicle 20 would see in rear
view mirror 26 that the marker 22 was moving from side to
CA 02073863 2001-04-30
_ g _
side and was out of alignment with reference marker 24.
Such a situation is illustrated in Figure 11.
A further example of misalignment is illustrated
in Figures 9 and 10. Towed vehicle 14, as illustrated in
Figures 9 and 10, consists of the combination of a car 13
with its front wheels 15 mounted on a single axle trailer
17. In Figures 9 and 10, towed vehicle 14 is illustrated
in a condition where one of the tie downs for the front car
wheels 15 has come loose thereby permitting one of the
wheels 15 of the car to come off the trailer 17. This is
a situation which is quite common in the trailer industry.
In the absence of the applicant's apparatus and method, the
car 13 would be dragged down the highway at an angle
thereby wearing away the rubber on the tires of rear wheels
19 of the car 13 and eventually even the metal rims of the
rear wheels 19. With the method and apparatus of the
invention, the driver of the tow vehicle 20 would see in
the side mounted rear view mirror 26 the view that is
illustrated in Figure 11, and can be alerted to a problem.
It is to be understood that the method and
apparatus of the invention perform properly in alignment
when the towing vehicle and the towed vehicle are travel-
ling down a horizontal straight road. The markers and the
reference markers move out of alignment when curved or
hilly grades are encountered. The driver is aware of this
and checks the markers and reference markers when travel-
ling on level straight roads. However, with experience,
the driver can learn to use the markers and reference
markers even on curves or hills.
Figure 12 illustrates an isometric view of a
specific rod-like apparatus 12 for monitoring towed ve-
hicles. Rod 12 consists of a plurality of tubular sections
30 which are telescopically connected. The sections 30 may
be telescopically extended to lengthen the rod 12 or
CA 02073863 2001-04-30
- 10 -
telescopically nested to shorten the rod 12 , in order to
accommodate various widths of towing vehicles 20. Rod 12
has a first end 32 which is secured to the towed vehicle 14
and a bulbous enlarged second end 22, which is readily
visible to the driver in the rear view mirror 26. It is
advantageous that the bulbous enlarged second end 22 is
made of materials which reflect light or are capable of
illumination in some way so as to improve visibility. It
is also advantageous that the bulbous enlarged second end
22 be adapted to withstand considerable abuse because it
will undoubtedly collide at some point with a stationary
object. For this reason, the construction materials used
must be durable, impervious to the elements, and impact
resistant in the event that the bulb 22 is struck against
another object. The applicant has found that a fluorescent
coloured cylinder with an impact resistant bumper on the
end is suitable for the purpose.
When the rod 12 is installed, first end 32 of rod
12 is secured by a spring 34 to the towed vehicle 14. The
spring 34 is advantageous because it enables pivoting.
Otherwise, the rod 12 will tend to break as a result of
excessive vibration on rough roads, or as a result of
striking a stationary object. An example where an object
may be struck by bulbous unattached end 22 of rod 12 is in
turning a tight corner where a power pole is positioned
immediately adjacent the corner. Rod 12 must be secured to
towed vehicle 14 in such a manner as to permit adjustment
on a vertical plane in order to allow bulbous unattached
end of marker rod 12 to be placed in linear alignment with
monitor projection 24. The specific embodiment illustrated
uses a bracket 36 which permits pivotal movement of the rod
12, not only for linear adjustment but also for movement
into a stored position when the rods 12 are not required
for monitoring purposes.
CA 02073863 2001-04-30
- 11 -
In a specific embodiment, the marker 22 may be
coloured yellow and the reference marker 24 may be coloured
red. In this way, the driver can readily identify each
component, by using any contrasting colour. If a middle
marker is used, it can be coloured amber, for example. In
another embodiment, the marker rod may be mounted horizon-
tally and the reference marker may be mounted vertically.
In this way, they act as one quarter of a set of cross
hairs. Thus the driver can readily detect when there has
been a change in the angle between the marker rod and the
reference marker.
The use of the apparatus illustrated has been
described in relation to the method of the invention. Rods
12 are pivoted from a stored position to an operative
position. The operative position is when the enlarged
bulbous ends 22 of rods 12 are extended telescopically
until they are visible beyond each side 18 of a tow vehicle
20. The spring 34 provides the resiliency required so that
when objects are struck during use, the rods 12 do not
become bent or break off.
In order to use the specifically described method
and apparatus at night, the enlarged ends 22 of the rods 12
must be visible to the driver of the tow vehicle 20 in his
side mounted rear view mirror 26. Light bulbs can be
installed in the enlarged ends 22. However, this is
relatively expensive. Further, the light bulb, and even
the wiring to the light bulb can break due to any impact
that the rods 12 receive when they strike stationary
objects. An alternative, less expensive and more trouble-
free method of illumination has been invented as illus-
trated in Figure 14. The method involves drilling a hole
41 through each of the rear tail lights 40 of the two
vehicles 20 and 14. An optic fibre 42 or a group of fibres
is then inserted into each of the holes 41. The optic
fibre 42 would normally be sealed in position by a clear
CA 02073863 2001-04-30
- 12 -
sealant 43 to keep water and dirt out of the rear tail
light. The optic fibre 42 in each rear light is aligned
with the respective enlarged ends 22 of the applicable rods
12 on the respective sides of the vehicle. Light from each
light bulb 46 within each rear tail light 40 then shines
through respective optic fibre 42 and produces a beam of
light 44 which is focused upon the enlarged end 22 of the
rod 12 that is located rearwardly of that light. This
makes the end 22 visible to the driver for night driving.
10~ In appropriate cases where two sets of rods 12 are used on
each side, a similar procedure would be followed by insert-
ing an optic fibre 50 into tail lights 48 of towed vehicle
14 to project beams of light 52 upon the bulbous enlarged
ends 22 of the rearwardly positioned rods 12. The fluor-
escent material on the ends 22 readily reflects the beamed
light and is easily seen in the rear view mirror 26. In
certain cases, it may be advantageous to illuminate the
moni~ors. However, generally, the monitor does not have to
be illuminated because it is used only to obscure the
marker. If the illuminated marker becomes visible to the
driver, then it has moved out from behind the monitor and
the driver knows then that there has been a change in
position.
The method as described provides a simple and
inexpensive method of monitoring towed vehicles, such as
trailers and the like, which are, or are not, visible in a
side mounted rear view mirror of a tow vehicle. The
apparatus, as described, provides an effective device for
use in accordance with the teachings of the method. It
will finally be apparent to one skilled in the art that
modifications may be made to the specific embodiments of
the apparatus. In particular, enlarged unattached end 22
of rods 12 need not be bulbous, as a different geometric
figure can be used. Also, various ways of illuminating the
markers can be used.
CA 02073863 2001-04-30
- 13 -
As will be apparent to those skilled in the art
in the light of the foregoing disclosure, many alterations
and modifications are possible in the practice of this
invention without departing from the spirit or scope
thereof. Accordingly, the scope of the invention is to be
construed in accordance with the substance defined by the
following claims.
