Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD FOR WRAPPING A LOAD
Field of the invention
The present invention relates to an apparatus and method for wrapping a
load by means of a flexible material. More specifically the invention relates
to an
apparatus for treating the two tails, or ropes, of a flexible wrapping
material in a
pallet wrapping machine.
Descriution of the prior art
Pallet wrapping machines are well known in the art, and consist essentially
of a frame on which is rotatably mounted a roll of flexible material. The
flexible
material is brought close to a load, usually conveyed by a conveyor to a
wrapping
area.
Presently, flexible material producers are marketing film material that can
be stretched up to 300% of the original length, which creates considerable
tension
during the wrapping cycle (tension is created when the wrapping material is
stretched because it is trying to get back to its original length).
Producers are also adding a tacky side to the material which helps one
layer to stick to the one previously applied. Static is also produced when
film is
stretched which also helps to stick to the previously applied layer.
Another material that is frequently used in pallet wrapping machines is
netting, commonly used for fresh fruits and vegetables. A few years ago,
netting
was not stretchable, but now netting producers are marketing netting that can
be
stretched up to 200%. Netting does not have a tacky side, nor does it produce
enough static to make the web stick to the load. A load wrapped with netting
would start unwrapping itself as soon as the web would be cut free to wrap a
subsequent load.
Known in the art is U.S. Patent no. 4.432.185 to Geisinger, which discloses
a pallet wrapper including a mechanism to hold a portion of the flexible
material in
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position prior to wrapping a load. The pallet wrapper includes an anvil member
movable into a position against the side of the pallet, and a clamp movable
with
the anvil and adapted to hold the portion of the flexible material. Once the
anvil
and the clamp are positioned against the side of the pallet, wrapping of the
pallet
is effected by known means. After the pallet has been wrapped at least by
covering with the flexible material the portion of the flexible material held
by the
clamp, the clamp is released and retracted and the wrapping of the pallet
completed. After the pallet is completely wrapped, the clamp is moved back
into
position to clamp a roped section of the web adjacent the clamp and a securing
mechanism is advanced to cooperate with the anvil to secure the web adjacent
the
clamp to the underlying roped layer of the web. A cut-off mechanism is
advanced
to cut the web between the clamp and the point of securement.
However, this pallet wrapper relies on the fact that there is a small amount
of tension in the wrapping material to maintain the portion of the flexible
material in
position during transportation of the pallet. If the flexible material is
stretchable
netting in the Geisinger machine, this portion of the flexible material is
loose, and
can unwind during transport. Using the Geisinger machine with stretchable
netting
is not an efficient, nor satisfactory process, since the portion of the
flexible material
that is "held" by the wrapped flexible material will not stay in place, and
the pallet
will eventually become unwrapped.
Summary of the invention
It is an object of the present invention to provide an apparatus for wrapping
a load by means of a flexible material which ties a first and second rope
portions
together, preventing the flexible material from unwrapping itself. In
accordance
with the invention, this object is achieved with an apparatus comprising:
supplying means for supplying the flexible wrapping material as a rope or as a
full
web;
first positioning means for positioning a portion of a first rope supplied by
the
supplying means at a predetermined location;
means for effecting relative movement between the load and the supplying means
to wrap the load by means of a full web supplied by the supplying means;
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second positioning means for positioning a portion of a second rope supplied
by
the supplying means at the predetermined location;
fastening means for fastening together said portions of the first and second
ropes
at said predetermined location;
cutting means for cutting the second rope between the portion thereof that has
been fastened and the supplying means; and
controlling means connected to the supplying means, the first and second
positioning means, the means for effecting relative movement, the fastening
means and the cutting means, for controlling operation thereof.
According to the present invention, there is also provided a method for
wrapping a load, comprising the steps of:
(a) supplying a flexible material as a first rope having an end portion;
(b) positioning the end portion of the first rope at a predetermined location;
(c) after step (b), supplying the flexible material as a full web;
(d) wrapping the load by means of the full web;
(e) after step (d), supplying the flexible material as a second rope;
(f) extending a portion of the second rope at the predetermined location;
(g) fastening the end portion of the first rope to the portion of the second
rope at the predetermined location;
(h) cutting a section of the second rope that is upstream to the
predetermined location.
Brief description of the drawings
The present invention and its advantages will be more easily understood
after reading the following non-restrictive description of preferred
embodiments
thereof, made with reference to the following drawings in which:
Figure 1 is a top view of an apparatus according to a preferred embodiment
of the invention where the conveyor is fixed;
Figure 2 is a side elevational view of the apparatus of Fig. 1;
Figure 3 is a rear elevational view of the apparatus of Fig. 1;
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Figure 4 is a schematic perspective view of the apparatus according to the
present invention, showing schematically the location of the first positioning
means, the second positioning means, the fastening means and the cutting
means, there are also shown the conveyor and the load;
Figures 5 to 13 are enlarged views of the circled portion of Fig. 4, showing
components of the apparatus in different operating position;
Figure 14 is a top view of a variation of the apparatus of the invention,
including a rotatable conveyor;
Figure 15 is a rear elevational view of the apparatus of figure 14;
Figure 16 is a side elevational view of the apparatus of figure 14;
Figures 17 and 18 are side views of the supply means showing the delivery
of the flexible material as a full web (Fig. 17) and as a rope (Fig. 18); and
Figure 19 is a schematic representation of the control means for controlling
operation of the apparatus according to a preferred embodiment of the
invention.
Description of preferred embodiments of the invention
Referring now to Figs. 1-3, the apparatus of the present invention includes a
frame 1 through which a conveyor 2 runs. On the frame 1 is mounted a flexible
material carriage 5. The flexible material carriage 5 includes a roll of
flexible
material 10 rotatably mounted on the carriage 5.
A load 3 to be wrapped is conveyed into a wrapping area by the conveyor 2.
As in the prior art, the apparatus includes means for effecting relative
movement
between the load and the supplying means in order to wrap the load. Figs. 1-3
show a preferred embodiment of the apparatus, where the supplying means are
mounted on an arm 4 through a boom 8, the arm 4 being rotatably mounted on the
frame 1 through a ring gear 7. Relative movement of between the load and the
supplying means is effected by moving the arm 4 around the load.
Referring now to figures 4 to 13, the present invention, as mentioned
above, concerns the addition, to a prior art apparatus, of first positioning
means for
positioning a portion of a first rope supplied by the supplying means at a
predetermined location; second positioning means for positioning a portion of
a
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second rope supplied by the supplying means at the predetermined location;
fastening means for fastening together said portions of the first and second
ropes
at said predetermined location; and cutting means for cutting the second rope
between the portion thereof that has been fastened and the supplying means.
5 More specifically, figure 4 shows schematically the location of the first
positioning means, the second positioning means, the fastening means and the
cutting means, identified by reference numeral 9. The supplying means are
mounted on the carriage 5 shown in figures 1 to 3.
Referring again to Figs. 4-13, the first positioning means include a first
gripper 35 for gripping an end of a portion of the first rope 39 upstream of a
predetermined position 40 (see Fig. 9); and a first finger 27 located
downstream of
the predetermined location 40 for positioning the portion of the first rope
from the
first gripper 35.
The second positioning means include a second finger 36 for locating an
end of a portion of a second rope 44 upstream of the predetermined location; a
movable guiding wheel 33 for positioning and guiding the second rope; and
moving means 30 for moving the guide wheel between a standby position and an
active position, where the portion of the second rope is positioned downstream
from the second finger, at the predetermined location.
The fastening means preferably include a clipper 34 for clipping together
the portions of the first and second ropes together at the predetermined
location
44, and means 30 for moving the clipper 34 between an operative position and
an
inoperative position.
The cutting means preferably include a heat wire 32, and means for moving
the heat wire 32 from an inoperative position to an operative position, where
the
heat wire is in contact with the second rope 44. Also preferably, the cutting
means
further include a second gripper 35 for gripping the second rope between the
portion thereof that has been fastened and the supplying means so that the
second rope is held in position to be cut between the second gripper and the
portion thereof that has been fastened. In this preferred embodiment, the
first
gripper and the second gripper are a single gripper 35 which is movable
between
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a first operating position and a second operating position, as will be
hereinafter
detailed.
At the very beginning, a first rope 39 is made from the flexible material 10,
and the rope 39 is loaded into the gripper 35 by pressing push-button 43 to
open
the gripper. As can be seen in Fig. 5, the gripper 35 is mounted on a rod-less
cylinder 38 via a rod-less carriage 29, the rod-less cylinder being mounted
between two up/down movement cylinders 31 and 26, each fastened to the
apparatus frame.
A load 3 is brought to the wrapping area by means of the conveyor 2. The
supplying means are directed to supply the flexible material as a rope, and
relative
movement between the supplying means and the load is effected. As this
movement occurs, the rope 39 catches on the first finger 27, as seen in Fig.
6.
After the rope 39 passes the first finger 27, the supplying means are
directed to supply the flexible material 10 as a full web, and wrapping of the
load 3
by usual procedures is effected. Preferably, the load can be tied by rotating
the
rope 39 around the load before it is wrapped.
Once the load has been wrapped, the supplying means are directed to
supply the flexible material 10 as a second rope 44 (see now Fig. 7).
The second finger 36, which is movable between an operative position and
an inoperative position, is brought from the inoperative position to the
operative
position, i.e. it is raised. The second rope 44 is caught by the second finger
36 in
order to place the second rope 44 in the required position. At this point,
relative
movement between the load 3 and the supplying means is stopped.
The guide wheel 33 is mounted on a clipping arm 42, in turn mounted on a
clipping arm rotary actuator 30. The actuator 30 is mounted to a lifting arm
25 and
secured to the frame by a bracket 24 and a lifting arm pivot point 37. The
lifting
arm is movable between a rest position and an operative position by means of a
lifting arm cylinder 28.
The clipping arm 25 is moved from the rest position (Fig. 7) to the operative
position (Fig. 8). The actuator is then rotated from its rest position to its
operative
position, causing the guide wheel 33 to push against the second rope 44
(Figure
9), and thus align the two ropes at a predetermined position 40.
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As can be seen from the Figures, the clipper is also preferably mounted on
the clipping arm 42. When the guide wheel pushes against the second rope 44 to
align the first and second ropes together, the clipper is actuated to clip the
first and
second ropes together.
Once the first and second ropes have been clipped together, a heat wire 32
may be activated to cut a portion of the second rope 44 downstream of the
predetermined position 40, thereby releasing the load. This would however mean
that a person would have to manually reload the gripper 35 for the next cycle.
Accordingly, and advantageously, prior to cutting the portion of the second
rope, the gripper 35 is opened to release the first rope 39. Subsequently, as
shown in Fig. 10, the gripper up/down cylinders 26, 31 are actuated to move
the
gripper downwardly to clear the clipping arm 42. The gripper 35 is then
retracted
laterally, passing under the clipping arm 42 (Fig. 11 ). The gripper up/down
cylinders are then actuated to move the gripper upwardly (Fig. 12), so that
the
gripper is now located between the guide wheel 33 and the heat wire 32, and
the
gripper is closed to secure the portion of the second rope 44 therein.
Finger 27 is then brought down to an inoperative position to release the
portion of the first rope 39. The heat wire is then activated to cut the
second rope
44 between the gripper 35 and the clipped rope 41. Finger 36 is retracted to
release the clipped rope 41, which, by virtue of the tension present, remains
against the load 3. The load is thus now released, and free to move on the
conveyor.
The rod-less cylinder 38, the actuator 30 and arm 25 are then moved back
to their initial positions, and the system is ready for the next load.
It should be noted that although a specific embodiment of the invention has
been described, the present invention consists in the combination of a typical
load
wrapping machine, with first and second positioning means, fastening means for
fastening the first and second ropes together and cutting means for cutting
the
second rope upstream of where it has been fastened to the first rope. Although
fingers, grippers, heat wires, clippers, etc. have been specifically described
and
illustrated, the objects of the present invention could easily be met with
other
mechanical devices fulfilling the same functions. Furthermore, in a preferred
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embodiment of the invention, the first and second grippers are a single
gripper
movable between a first and second operative positions, but two individual
grippers would without difficulty achieve the same function. Also, the clipper
34,
guide wheel 33 and heat wire 32, shown being mounted on a single arm, could
also be individually mounted and controlled.
Referring now to figure 19, in order to control operation of the machine and
timing thereof, a controller 50 is provided, which is preferably housed in
control
panel 6. The controller has a plurality of inputs 51-61 and a plurality of
outputs 62-
72. Inputs 56 and 57 are indicated as referring to finger "A" and finger "B"
respectively, which correspond to the first 27 and second 36 fingers,
respectively.
The inputs are provided through reed switches, proximity sensors and
photosensitive sensors which sense displacement and location, so that
controller
"knows" where all of the components are at any time in the cycle, and sends
out
the appropriate outputs.
The apparatus according to the present invention can thus wrap loads 3
with traditional film or netting, both of which are included in the expression
"flexible
material" used in the present description and claims.
In an alternative embodiment of the invention, shown in Figs. 14-16, the
supplying means are mounted on a tower 13 and the load is conveyed to a
turntable conveyor 11, so that the load is fixed but the turntable conveyor
rotates
to effect relative movement between the load and the supplying means. In such
a
case, the apparatus base frame 20 supports a ring gear 23, and the turntable
conveyor 18 is driven by motor 22 through reducer 21. The supplying means
comprise a roll of film 15. A film delivering carriage 14 supports the roll of
film 15.
Referring now to figures 17 and 18, the carriage 5 has guiding means, here
preferably including a cylinder 17. The cylinder 17 is spaced apart to an
elongated
element to delimit an elongated gap through which the flexible material 10 is
supplied. A roping wheel 16 and moving means for moving the roping wheel 16
along the gap are provided so that in a first operating position, the flexible
material
10 is supplied as a full web 12, and in a second operating position, the
flexible
material 10 is supplied as a rope 39 or 44.
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Although the present invention has been explained hereinabove by way of a
preferred embodiment thereof, it should be pointed out that any modifications
to
this preferred embodiment within the scope of the appended claims is not
deemed
to alter of change the nature and scope of the present invention.
