Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2144886
,
FIELD OF THE INVENTION
The invention relates to lift trucks known as
forklift trucks, and in particular, to a video camera
guidance system for lift portions of such trucks.
BACKGROUND OF THE I~v~NllON
Forklift trucks are widely used in industry for
moving heavy loads of goods. Frequently, loads of goods
are stacked on shelving in a warehouse. The shelving may
reach a height of many feet. The forklift trucks
designed for this purpose usually have a elevator
mechanism by which the forks of the truck can be elevated
up to the level of a particular load, or a particular
shelf. The elevator mechanism raises the forks more or
less directly above the truck or vehicle on which they
are carried, and on which the operator is seated or
standing. Consequently, the operator has little or no
chance of actually observing the forks, at that height
directly above him, and determining whether or not the
forks are at the correct height, and whether or not the
forks are aligned to enter the pallet supporting the load
of goods.
Similarly, if the operator is placing a load of
goods on a high shelf, the same problems arise, and it is
easy for him to raise the load too high, or to place it
too low, and then to attempt to advance it into position
on the shelf, and likely cause damage.
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BRIEF SUMMARY OF THE INVENTION
With a view to overcoming the foregoing
disadvantages, the invention comprises a forklift truck
having a truck body adapted to be operated by an
operator, a fork assembly which can be elevated above the
level of the body, a video camera attached to said fork
assembly and servo motor means connected to said video
camera whereby said camera may be directed in various
directions, and connection cables connecting said video
camera to said vehicle, and a display monitor on said
vehicle and controls on said vehicle for directing said
camera , whereby an operator may observe through said
camera and said display monitor, the position of the
forks and the position of a load, and may adjust the
direction of the camera, so as to look at various
different portions of the load, and the forks, and the
shelving, and, a lighting device attached to the forks,
the lighting device providing illumination of the shelf
area in front of the forks, so as to illuminate the
objects being viewed by the camera.
In one form of the invention the lighting device is
fixed in position, and is aimed and directed so as to
direct its beam along a beam axis which is parallel to
the axis of the forks. In this way when the forks are
tilted up, or down, the light beam also tilts up or down,
and enables the operator to determine the exact angle of
tilt, through the monitor.
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In another form of the invention the lighting device
may be moveable in somewhat the same way as the camera
itself, so that it may both be used for examining a
larger area, as well as for aligning the forks with a
pallet.
The various features of novelty which characterize
the invention are pointed out with more particularity in
the claims annexed to and forming a part of this
disclosure. For a better understanding of the invention,
its operating advantages and specific objects attained by
its use, reference should be had to the accompanying
drawings and descriptive matter in which there are
illustrated and described preferred embodiments of the
invention.
IN THE DRAWINGS
Figure 1 is a schematic side elevation of a typical
forklift truck, showing portions of the camera and
lighting attached thereto and showing movement in
phantom;
Figure 2 is a front perspective illustration of the
forks of a forklift truck showing the location of the
camera and the light, and,
Figure 3 is an enlarged perspective of the camera
showing its mobile means of attachment and servo motors.
DESCRIPTION OF A SPECIFIC EMBODIMENT
Referring first of all to Figure 1, it will be seen
that the invention is there illustrated as applied to a
typical forklift truck indicated generally as 10.
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It will be appreciated that there are a wide variety
of different forms of such forklift trucks, and the one
illustrated is shown purely for the sake of example, by
way of illustrating the invention. The invention is not
restricted to any particular form of forklift truck, but
would be equally applicable to a wide variety of trucks
and lift vehicles with minor modifications.
Typically such a truck 10 will have a fork assembly
12, usually having forwardly extending tines 14 and a
back frame 16. The back frame 16 is usually mounted on a
elevator mechanism 18. In addition, the back frame is
mounted on an extension mechanism 20, by means of which
the fork assembly may be extended away from the elevator
mechanism, and retracted towards it and the forks
assembly incorporates a known tilt mechanism by which the
forks may also be tilted up or down.
All of these features are well known in the art
relating to lift trucks, and require no special
description.
As is well known to persons using or watching such
lift trucks in use, a load usually resting on a pallet,
is placed on the forks. Frequently, this is done at
ground level, or for example, from the bed of a truck
(not shown). At this level, it is relatively easy for
the operator to see what is happening and he can guide
the tines of the forks directly into appropriate openings
in the pallet. He can then operate the mechanism and
raise the pallet.
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Usually, he will then move the truck to a location
in the warehouse, where the goods are to be stored. At
this point, the warehouse may contain shelving many feet
high. It may then be necessary for the operator to raise
the forks upwardly by means of the elevating mech~n;sm
until he reaches a level of the shelves on which he
wishes to deposit the load. He must then advance the
extension mechanism so as to move the entire pallet and
forks over the shelf. He then lowers the tines so that
the pallet rests on the shelf. He then withdraws the
tines from the pallet, and lowers the forks back down to
ground level.
This part of the operation, i.e. placing a load on a
shelf, is relatively easy for a trained operator.
The reverse operation i.e. the retrieval of a pallet
load from elevated shelving takes place in the reverse
manner. It is, however, more troublesome and can lead to
accidents.
In the case of the pallet retrieval, the operator
does not have a view of what is happening at the level of
the forks and the pallet. These are both located many
feet above his head and it is impossible for him to see
what is happening. Consequently, accidents are not
infrequent. In fact, many forms of lift trucks
incorporate a roof 22 specifically to designed to protect
the operator in the event that a load is accidentally
dropped.
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In order to provide visual guidance for the operator
so that he can actually see the forks and the load and
the shelf at whatever height he is operating, the
invention provides a video camera 24 mounted on the
forks, typically on the rear frame 16. The camera is
mounted behind the frame, so as to avoid contact with a
load of goods on the tines. The video camera is mounted
on a up and down pivot mount 26, and is also mounted on a
side to side traverse mount 28. These two mounts are
controlled by servo motors 30 and 32. Operation of the
servo motors will therefore either tilt the camera up or
down, or rotate it from side to side. The camera may
also be equipped with a servo focusing mechanism such as
is well known in the camera art, so that the operator can
also focus on either near or distant fields.
Cables 34 connect the camera servo motors to
suitable controls 36 on the truck for controlling the
position of the camera, and of course, connect the camera
itself to a monitor display 38 these being mounted on
the vehicle or truck.
In order to illuminate the field in front of the
camera, and so as to provide additional means of guidance
for the operator, a light 40 is fastened to the frame 16
of the forks behind frame 16. In a typical case, this
light may simply be secured to the frame. Thus when the
tines are tilted upwardly, tilting the frame rearwardly,
the light beam will swing upwardly, and when the tines
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are tilted downwardly, the light beam will swing
downwardly.
This will provide the operator with the ability to
detect the angle of tilt of the tines, and will also
provide illumination for the pallet into which he must
insert the tines.
In order to provide greater versatility, it may be
desirable to provide the light with a mounting, similar
to the camera, so that it may be swung upwardly or
downwardly, or from side to side, so as to illuminate
fields over a greater area. In the simplest case
however, this is not intended, since the light, being
fixed to the frame of the forks, will tilt up or down
according to the tilting of the tines, and this will
provide adequate movement for the light beam in most
cases.
Again, cables 34 extend from the light down to the
vehicle, which provides a suitable source of power for
illuminating the light.
In addition, in order to permit extension of the
forks to a considerable elevation, the cables are
preferably wound around a level wind up device indicatéd
generally as 42, which will automatically retract the
cables as the forks are lowered and will permit them to
extend, as the forks are raised.
The operation of the invention is self evident from
the foregoing.
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The foregoing is a description of a preferred
embodiment of the invention which is given here by way of
example only. The invention is not to be taken as
limited to any of the specific features as described, but
comprehends all such variations thereof as come within
the scope of the appended claims.
