Note: Descriptions are shown in the official language in which they were submitted.
CA 02416241 2003-O1-14
BOTTOM SAW BLADE HEIGHT ADJI1STMENT
FIELD OF THE INVENTION
The present invention relates to the recycling field and more specifically to
the handling of
empty bottles returned in their originally provided carton for re-use or
recycling. In particular,
the invention is concerned with separating in a continuous manner empty
bottles from cardboard
cartons containing same.
BACI~GROIIND OF THE INV~:NTION
In the beverage industry, particularly the brewing industry, there are certain
advantages to the
use of refillable primary containers, such as glass bottles, in preference
over cans or other non-
refillable containers. Refillable bottles are ecologically friendly and enjoy
a very high return rate
because there is an incentive for consumers to return the bottles - namely, to
obtain a mandatory
refundable deposit on the bottles. It may be noted however, that the non-
refillable primary
containers are frequently returnable for recycling as scrap metal, glass etc.
and separation of
those containers from their package must also be effected.
A disadvantage of using refillable bottles, from the standpoint of the
bottler, is that refillable
bottles can be difficult or awkward and expensive to handle. They must be
separated from the
packaging in which they have been returned, labels removed, cleaned, and
sterilized before they
are re-used. There are numerous machines available for many of the required
activities e.g. the
cleaning and sterilizing steps of the bottles. Design of a machine at
reasonable cost in these
areas of handling can be simplified somewhat by the standardized sizes and
shapes of bottles.
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CA 02416241 2003-O1-14
It is more difficult, however, to automate those steps of the bottle handling
process dealing with
removal of the bottles from their associated packaging which, obviously must
take place before
individual bottles can be dealt with. Most bottles are returned to a facility
in the packaging in
which the bottles were sold to the consumer. In Canada, beer bottles are
packaged most
frequently in six, twelve and twenty-four bottle cartons, the twelve
frequently having a three
bottle by four bottle configuration, and the twenty-four having a six bottle
by four bottle
configuration. The twelve and twenty-four battle cartons are generally made
from cardboard, the
former usually paperboard and the latter, the thicker corrugated cardboard.
It will be appreciated that a carton full of empty bottles when returned may
be wet, bent, ripped,
folded in an unusual manner, have missing parts, filled with debris or broken
glass, or otherwise
not in an ideal condition for handling. The inconsistent condition of returned
cartons makes
them difficult to process automatically, but because of the low value of their
contents, they must
be processed very quickly and efficiently to keep costs at an acceptable
level. Furthermore, it is
common for the brewer to receive cartons of various sizes together on the same
pallet. For
example, a layer of 24's will sit on a layer of 12's.
Heretofore, one of the most efficient ways of removing bottles from returned
cardboard cartons
has been to use a band saw to cut across a carton near its base, thereby
severing the base from the
walls of a carton and then hand stripping the loose walls of the carton then
in the form of a
sleeve - from over the bottles. A problem with this method is that the saw
blade, upon initially
contacting the case side wall, a bottle inside the carton higher than is
optimally desirable if bottle
damage is to be avoided.
A further problem centres around the fact that the heel of the bottle is made
of relatively thick
glass, but the main body above the heel is not and is therefore, more
susceptible to damage if
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struck by a saw blade. It is therefore very important that the saw blade is
accurately positioned
above the conveyor surface to ensure that it does not strike bottles in the
carton above the heel.
Moreover, the various types and sizes of carton may be made of different
materials which
usually do not have the same thickness. For example, 6-packs (6-packs have one
layer but the
returns are in trays) and 12-packs (12-packs have only one layer for its
bottom) are usually made
of relatively thin chipboard whereas 24-packs are made of thicker corrugated
board (24-packs
have two layers of board for its bottom). Consequently, the bottles in
different sized cartons
moving on the same conveyor are spaced from the conveyor surface different
amounts.
Unfortunately a mixture of carton sizes are returned together to the brewer
and it is not really
feasible to sort these prior to them being carried to the saw device for
treatment. In the
circumstances, if continuous operation is to be maintained, a compromise or
average position
above the conveyor surface is usually chosen which can cause problems of the
type discussed
above.
Canadian Patent No. 2,216,395 provides a method of cutting open the beer
carton to expose the
neck of the beer bottles in the carton, so that the bottles can be accessed by
in-line equipment,
rather than by overhead equipment. The patent teaches a complex device using
multiple rotary
saw blades to cut through the side walls of opposed sides of cartons from end
to end as said cases
are moved past said saws and, subsequently, carton orienting means are
situated downstream of
said saws to present the uncut side walls of said cartons towards the sides of
said conveyor; and
further saws are arranged at the sides of said conveyor belt to cut through
the remaining two side
walls of said cartons from end to end as said cases are moved past the further
saws to sever the
tops and a portion of said side wall. This is obviously a complex and
expensive system requiring
significant maintenance.
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It is an objective of the present invention to provide a method and apparatus
for use in a system
for continuously separating bottles from cartons in which they are enclosed
thereby allowing
same to be economically re-used or recycled.
SUl~~IIVIAItY O~' TIIE INVENTION
This is achieved by providing a saw station to which the filled cartons are
lead and at which, a
saw severs the base or bottom by cutting through a lower portion of the carton
walls to which the
base is attached. The saw blade is arranged to cut the walls just above the
surface of the base or
bottom on which the bottles rest thus minimizing contact between the saw blade
and the bottles.
An important feature of the invention is that the height between the saw blade
and the support
surface or table on which the filled cartons are sitting when treated be
variable at least at the
place of contact between the carton and the saw blade so that the saw blade
can be maintained at
an optimum position to minimize adverse contact with the bottles despite
variances in thickness
of the material of the bases of the cartons arriving at the station. These
variances of course,
result in the distance the base of the bottle is from the support surface also
varying and increased
risk of the blade contacting and chipping etc. the bottle higher up or above
the heel. The
adjustment of the vertical distance between the saw blade and at least the
edge of the table
adjacent the saw blade can be achieved by arranging for the saw blade or the
table edge, or both,
to be vertically moveable relative to the other. It is preferred that the
table edge be movable
relative to the saw blade. Moreover, it is most preferred that the relative
movement to achieve
optimum by aligned cutting action be made automatically to accommodate each
carton as it
enters the saw station. The desired adjustment may be effected mechanically or
by providing
means, such as a pneumatic or hydraulic simple piston and cylinder
arrangement, to lift or lower
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the table vertically toward or away the saw blade, or vice versa, which means
may be operated
by hand but preferably automatically. In a preferred aspect of the invention,
it is activated in
response to a signal from a sensor (sensors) located in an inspection station
upstream from the
saw station. The sensor (sensors) is (are) programmed to differentiate between
(24's and 12's
using the handle opening of the 12-packs) cartons having bases or bottoms of
differing thickness
travelling on a feed conveyor; evaluate the table setting for each identified
container based on
preprogrammed table height criteria and, following a delay calculated to allow
each specific
carton to reach the saw station and thereby be located on the table, make any
required height
adjustment. In this way, it is ensured that the vertical height or distance
between the saw blade
and the adjacent downstream edge of the table is optimum for the thickness of
the base of the
specific container then located at the saw station. The carton at the station
is generally urged
through the station by the following carton.
Preferably the saw blade is a band saw blade operating in a continuous loop
mariner although
other types, such as a reciprocating band saw could be used. Also, the blade
may be oriented at
an angle to the longitudinal axis of the station and carton support so that
butting of the carton
wall commences initially at one corner of the carton and then progresses
across the carton. This
provides a cleaner cut especially at rapid carton treatment rates.
It is also preferred to provide a slot or opening below the saw blade through
which the severed
base can enter and be removed. Following exiting the saw station, the carton
walls and top, if
any, are readily removed manually or by mechanical means, such as gripping
claws or suction
devices.
In this specification, removal of bottles from a carton and removal of a
carton from enclosed
bottles are considered the same.
CA 02416241 2003-O1-14
The present invention will be described with reference to the accompanying
drawings which
show a preferred embodiment thereof and in which:
FIG. 1 is an angled perspective showing in part a saw station of the present
invention;
FIG. 2 is a similar view to FIG. 1 but showing the saw blade in its raised
position;
FIG. 3 is a top perspective of the upstream conveyor delivering bottle-filled
cartons to the saw
station;
FIG. 4 is a view from below of part the piston - cylinder arrangement which
provides the vertical
movement of the carton table saw arrangement;
FIG. 5 is a part cross-section through a carton and one enclosed bottle
located on a carton
support at a saw station of the present invention.
In the following, the bottle recovery line is set up to handle a mix of 12-
packs and 24-packs (and
6-packs in trays) of empty beer bottles.
In the drawings, a saw station, generally designated 10 and shown in detail in
FIGS. 1, 2 and 3,
is served by an upstream plate conveyor 12 which brings cartons 14 and 15 to
the station 10 and
downstream or exit conveyor 16 which carries away bottles enclosed within a
carton, the bottom
of which has been severed and removed at the station 10. The station 10
effectively connects
conveyors 12 and 16 and comprises a carton supporting-table 18 having a
downstream edge 19
and, adjacent thereto, saw blade 20, all but the cutting edge 22 thereof being
located under dead
plate 24 which has an upstream edge 26 which restricts blade 20 from
significant vertical
movement. Between cutting edge 22 and edge 26 of plate 24 is a slot 28. It
should be noted,
please refer FIG. 5 that blade cutting edge 22 is not only laterally spaced
from plate edge 26 but
also vertically spaced, a height or distance "h" calculated to ensure that
cutting edge 22 contacts
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the side wall 30 of a carton 32 arriving at table 18 at the correct pre-
determined height. The
objective is to minimize saw contact with the bottle 33, specifically the
bottle wall 34, radially
outermost bulge 36 formed at the join of the bottle wall 34 and bottle base 38
- refer FIG. 5 - It
may also be noted that carton table 18 has a length less than the length of
the carton 30 and
consequently, the carton (not shown) following carton 30 which is on plate 24
continues to move
under the influence of conveyor 12 to smoothly urge carton 30 which is on the
plate, through the
station 10.
The edge 22 of saw blade 20 is preferably angled at about 20° to the
longitudinal axis of table 18.
This ensures that severing of the container walls commences at one relatively
small locality and
then progresses across the carton front or end wall 32 simultaneously with a
side wall. This
assists in providing a clean cut especially when handling tartans at higher
speeds.
Included in FIGS. 1 and 2 for illustrative purposes is a rectangular member 37
which has a slot
39 cut in at one end. This shows the two height settings for the blade 20 in
this embodiment.
FIG. l, the blade 20 is at its lower position where it can optimally handle
thin bottomed 12-
packs and in FIG. 2, blade 20 is at its elevated position to better handle
thicker based 24-packs.
Turning to FIG. 3, an upstream section of conveyor 12, is provided with
optical sensors 40 and
42. Sensors 40 and 42 are adapted to detect handholes, if any, in the longer
side wall 44 of a
carton 44. In this situation, if a handhole is detected, this identifies that
specific carton as a 12-
pack which has a bottom made of relatively thin paperboard. If no handhole is
detected, then the
carton must be a 24-pack, where the handholes are on the end or short walls,
which has a bottom
made of relatively thick corrugated board. The blade 20 and its edge 22 is
maintained for
example at the height required for 24-packs. Consequently, if a 12-pack is
detected, then the
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table 18 will need to be raised or lowered to reduce height "h" to the level
optimum for thinner
bottomed 12-packs.
Detection of which of the two types of carton a specific carton is made a
distance upstream from
the saw station. Consequently, when sensor 42 detects a case and sensors 38
and 40 detect a
hole, a signal is send to raise table 18 after a length of time determined by
an encoder. This
depends on a number of factors such as the conveyor 20 speed; distance from
the inspection
station to the saw station 10; etc. and is readily calculated for each
specific conveyor line
situation.
Table 18 is carried by brackets 46 which are mounted on beam 48 which itself
is support on
pneumatic pistons 50 associated with cylinders 52. Cylinders 52 are supplied
with plant
compressed air via lines 54. The cylinders are activated to raise the table by
a simple controller
(not shown) in response to the delayed signal from the sensors 40 or 42. The
table 18 adjusting
pneumatic system receives a constant stream of actuating signals from the
sensors 40 or 42 and
adjusts the table 18 or maintains it as is depending on each signal.
Obviously, if only one type of
carton, say 24's are being handled, the table 18 will not move at all
following it being set for that
carton size.
Turning to FIG. 5, this illustrates in detail the problem being addressed by
the present invention.
A carton generally designated 56 having a base 58 and one bottle 33 of the
complement of
bottles in the carton are shown sitting on carton support table 18. Bottle 33
has a main
cylindrical body 34 (shown in part), a base 38 and a configured heel 36.
Laterally and vertically
spaced from table 18 are band saw blade 20 and associated dead plate 24. The
vertical distance
between table 18 and saw blade 20 is termed "cutting height" and is indicated
as "h" in FIG. 5.
As will be appreciated, the optimum height "h" is one wherein saw blade 20
would, when it had
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cut through carton side wall 34, pass along a plane parallel to and
immediately above carton base
58. An elongate slot 60 is provided between saw blade 20 and table 18 into
which the base 58 as
it is severed by saw 20, commences entering and, when totally severed from all
from side walls
of the carton, falls totally into and is collected. During that action, bottle
33 and the other bottles
in the carton together with the bottomless carton ride up and onto dead plate
24 and, since they
are pushed and urged continuously by the next carton (not shown), continue
onward to exit
conveyor 16. It should be noted that the saw blade 20 contacts the radial heel
36, if at all,
generally most at its lower part and not at its middle part or thereabove. If
the saw 20 strikes the
heel higher than the centre of the bulge 36 not only is there a real risk of
damage to the bottle 33
up to breaking it open but also the saw can be damaged and consequently have a
shorter useful
life etc. Moreover, a shutdown of the line is most probable and, but not
least, there are possible
health risks of broken glass despite a "box" or cage being positioned around
the saw station to
minimize the broken glass risk and also to cut down on the noise generated.
In any event the present invention ensures that the correct cutting height "h"
is used
notwithstanding the different thickness of base 58 of the different types of
cartons being handled,
especially since on most occasions, the cartons being handled are not of one
type and
consequently, bases of different thicknesses have to be dealt with.
The 24-packs are made of relatively thick corrugated board which results in a
relatively "thick"
carton base or bottom which requires the saw blade 20 to be set a certain
predetermined height
above table top 18. However, a 12-pack carton is made of relatively "thin"
paperboard which
means that the blade 20, if maintained at the optimal height for 24-packs,
could strike the bottles
over the bottle heel and chip the bottles resulting in leakers or weakened
bottles which could
subsequently explode upon being refilled.
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