Note: Descriptions are shown in the official language in which they were submitted.
CA 02741247 2011-05-27
TITLE OF THE INVENTION: AUTOMATIC BAG SLITTER, AND METHOD
OF USE THEREOF
FIELD OF THE INVENTION
This invention generally relates to a bag opening machine of the kind
which receives bags, in the form of sacks made from paper or sheet plastics
material, and
feeds them past means for cutting the bags to permit them to be opened for
emptying.
BACKGROUND OF THE INVENTION
Many kinds of bag opening and emptying machine are known. Commonly
encountered problems include the need to orientate and position the bags with
some
accuracy before presenting them to the cutting means. Also, an oft occurring
problem is
that the bags accidentally retain at least some of their granular product
material, after the
cutting and opening thereof, on account of the way in which the bag is cut or
subsequently manipulated for emptying, thus leading to inefficiencies due to
waste.
Another drawback of prior art bag slitting machines, is that they are
usually not suitable for food grade application, since in such applications,
at least some of
the entire bag conveyor assembly, cutter assembly and/or empty bag compactor,
are
exposed to the food during opening and emptying of the food material inside
the bag,
thus leading to high likelihood of contamination hazard of the food material
from
external contaminants before economical reclaim of the food material.
Moreover, known bag slitting machines usually cannot be washed or dried
without any impurities left over. In particular, in prior art slitting
machines, the male cam
rollers enter and exit the full loaded bag slitting and emptying chamber, and
slide over the
stationary female cams, thus undesirably creating conditions for accidental
contamination
of the product released from the bag.
1
CA 02741247 2011-05-27
,
,
Also, existing designs of bag slitting machines are complex, including many
nuts and
bolts, gaskets, PVC belting, washers, and others, which increase the risk of
maintenance
downtime.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide a bag opening
machine which overcomes, at least to some extent, the problems aforesaid.
A further object of the present invention is to improve upon the bag opening
machine
disclosed in United States patent N 4 504 183 issued March 12, 1985 to JSK
Company
Ltd (inventors Stewart Bennison and Ronald Linnik).
SUMMARY OF THE INVENTION
According to the present invention, there is disclosed an automatic bag
slitter preferably made of modular assemblies including: a spike star wheels
assembly
module, which can be slid in and out of the machine as one complete assembly;
an infeed
conveyor assembly module, which can be slid in and out of the machine as one
complete
assembly; a compactor module, which can be slid in and out of the machine as
one
complete assembly; and a vibrating screen and hopper module, which can also be
slid in
and out of the machine as one complete assembly.
The automatic bag opening and slitting machine has a spike star wheels
assembly comprising either of one or a combination of star wheels or
cylindroid drum
like object. The star wheels assembly is provided with spikes which convey a
bag,
impaled on the spikes when in an extended position, and extends beneath rotary
cutting
disks driven by two independent pneumatic or electric motors, that may make a
continuous cut around three sides of the bag, so that after cutting thereof,
the bag
comprises two halves joined only at the rear or trailing side of the bag.
These two bag
halves are unfolded as one half of the bag engaged by the spikes is drawn
around the
upstream end of the star wheels assembly, while the other half slides over the
rocker
arm/bag separation bar/slide guide bar, thus emptying the powder/granular
content of the
bag into a hopper and releasing the emptied bag by retraction of the spikes
from the bag
2
CA 02741247 2011-05-27
,
for collection therebelow into a chute, for disposal into an endless screw
which extrudes
the bag into a compaction tube. The compacted bags are thereafter pushed into
a waste
plastic bag for refuse disposal.
This invention provides more particularly a machine for opening, cutting and
emptying bags filled with granular/powder material and the like. This machine
comprises a conveyor in the form of a star wheels assembly equipped with a
spike bar
rotatably mounted thereon, the spike bar having integral spike members which
can be
extended radially outwardly from and retracted radially inwardly of the
conveying
surface of the star wheels assembly and means for feeding a bag to be opened
and
emptied to the star wheels assembly, which is arranged: (i) to convey the bag
(impaled
on the spikes thereof¨when in their radially extended positions) to and past
cutting
means which act to make a continuous cut around three sides of the bag so that
after
cutting thereof, the bag comprises two halves joined only at the rear or
trailing side of the
bag; (ii) to allow the two halves of the bag to unfold as the half thereof
engaged by said
spike members is drawn to the forward end of the conveyor, thus enabling full
emptying
of the contents of the bag into receiving means therefor, and (iii) to release
the empty
bag (by retraction of said spike members) to collection means therefor.
This machine is characterized by the use of modular type spike conveyor
assembly
with single axle to which are journaled multiple star wheels, spacedly from
one another.
A module is provided for cutting and emptying full loaded bags containing food
products. A further module is provided for emptying bags wherein the material
inside the
bag is treated in a controlled and/or sanitary and/or aseptic environment, not
excluding a
negative pressure environment to prevent accidental release of hazardous
material inside
the machine, or positive pressure environment to prevent accidental ingress of
contaminating external material. Also included is an improved bag cutting
knife arm
assembly, an improved cam design, an improved bag separation guide bar; and an
improved modular type impaling spikes assembly.
3
CA 02741247 2011-05-27
=
More particularly, the invention relates to a bag opening and emptying machine
for cutting bags inside a controlled environment bag slitting chamber, said
machine
comprising: a star wheels assembly, including rotatable integral shaft
transversely
carrying a set of star wheels spaced from one another, wherein a spacer gap is
formed
between each pair of successive said star wheels along said shaft, spike means
mounted
within corresponding said spacer gaps and extendible radially outwardly from
and
retractable radially inwardly of the periphery of said star wheels assembly,
means for
feeding a bag into the controlled environment chamber and onto a conveying
surface of
said star wheels assembly; means for extending said spike means radially
outwardly of
said star wheels assembly so as to impale the bag and firmly secure the latter
to said star
wheels assembly; cutting means adjacent the star wheels assembly past which
the bag is
conveyed in a conveying direction and which serve to make a continuous cut
around
three sides of the bag whereby the bag is cut into upper and lower halves
hingedly joined
at the rear or trailing side of the bag; the star wheels assembly serving to
convey one half
of the bag impaled on the spike means while the other half unfolds therefrom
to release
the contents of the bag, and defining peripheral quadrants; receiving means
for collection
of the contents of the bag, means for retracting said spike means to release
the empty bag
from the star wheel assembly, and collection means for the empty bag.
Preferably, the star wheels assembly is located beneath the path over
which the bags travel during ingress from said means for feeding a bag and
into said
chamber, said star wheels assembly unfolding the two halves of the bag by
drawing the
half thereof engaged by said spike means over said star wheel assembly, and
further
including screen means to support the upper half of the bag as the bag is fed
over the star
wheels assembly and before it is drawn to follow the lower half around said
star wheels
assembly.
A number of radially outwardly opening notches could be formed at the
periphery of each of said star wheels, and actuator rods each extending
through
registering said notches from corresponding successive said star wheels, said
actuator
rods cooperating with said spike means, with said means for extending the
spike means,
and with said means for retracting said spike means.
4
CA 02741247 2011-05-27
Said actuator rods could be rotatably mounted relative to said star wheels,
and wherein said spike means are arcuate hooks, each of the latter having a
sharp leading
edge, said notches and associated actuator rods distributed on successive
peripheral
quadrants of each of said star wheels.
Preferably, said means for extending said spike means and said means for
retracting said spike means consist of female cam means and resilient means
urging said
actuator rods to a position where the arcuate hooks protrude radially
outwardly from the
conveying surface, and a cam roller associated with each said actuator rod,
each said cam
roller cooperating with said female cam means such that the actuator rods are
rotated
against the action of said resilient means to retract said arcuate hooks and
subsequently
release said arcuate hooks at required positions in a closed loop.
Said star wheels assembly could form a modular component slidably mounted in
and out
of the controlled environment bag slitting chamber, for facilitating
maintenance thereof.
Said cutting means could include either two electric or two pneumatic drive
motors spaced from one another, each of said motors driving a shaft carrying a
rotatable
blade, each drive motor supported into said chamber, each such motor, shaft
and blade
located in an operative condition thereof inside said chamber.
Alternately, said cutting means comprises two cutters which are arranged for
movement inside said chamber in a conveying direction and laterally to said
conveying
direction to opposite sides respectively of said star wheels assembly,
including resilient
means which act to urge the cutters inwardly, one of said cutters being
located behind the
other in said conveying direction whereby each cutter engages each bag in
cutting
relationship in precisely the same position on the bag surface to ensure a
continuous cut
around three sides of the bag.
Each cutter may comprise a discoid cutting blade disposed in a plane parallel
with
an upper bag conveying surface of said star wheels assembly.
Preferably, there is further included air jet means mounted either in said
star
wheels assembly or in the rocker assembly, in closely spaced fashion relative
to the
5
CA 02741247 2011-05-27
downstream quadrant of said star wheels assembly and for engaging an inside
surface of
the bag as it is unfolded and emptied.
At least some of said spike means could include arcuate hooks, angled in
said conveying direction and wherein said bag conveying surface of said star
wheels
assembly extends substantially horizontally and immediately downstream of said
cutting
means.
Preferably, said cutting means drive motors, shafts and blades form a unitary
modular component slidably mounted in and out of said controlled environment
bag
slitting chamber, for facilitating maintenance thereof.
In one embodiment of the invention, a rocker type guide bar frame is pivotally
mounted into a downstream portion of the controlled environment bag slitting
chamber,
said guide bar frame registering with said conveying surface of star wheels
assembly and
enhancing bag separation after said bag is cut by said cutting means, said
rocker type
guide bar frame forming a module releasably mounted into said chamber wherein
maintenance of said guide bar frame is facilitated when released from said
chamber.
Such guide bar frame could be selected from the group comprising a cross-
sectionally
triangular shape frame and a cross-sectionally T-shape frame, and preferably
incorporating integral air outflow jet nozzles.
Preferably, said collection means for the empty bag consists of a bag
collection
chute, mounted beneath said star wheels assembly, and a powered endless screw
system,
operating within a compaction tube and pushing the empty bag away from said
chamber
toward a reclaim area, said endless screw system extruding the bag into
another chute
where the emptied bags are compacted and pushed into a waste plastic tube.
Said cam means could be a female cam groove, made into an anchor plate at one
end of said star wheels assembly, said female cam groove engaged by said cam
roller.
In one embodiment, said receiving means consists of a collection hopper,
mounted into said chamber beneath said star wheels assembly, and a fine mesh
screen,
mounted within said hopper.
6
CA 02741247 2011-05-27
Preferably, there is further included means inducing high frequency vibration
of
said mesh screen.
Preferably, said guide bar frame includes a hollow elongated frame element
having a series of lengthwisely spaced openings, the latter opening forming
air outflow
nozzles, and further including a pressurized air source feed means operatively
connected
to said guide bar frame element and enabling pressurized air ejection
outwardly
therefrom through said air outflow nozzles.
The invention also relates to a method of slitting open a bag with a bag
opening
and emptying machine of the above-noted type, wherein the method comprises the
following steps: actuating said means for feeding a bag and feeding a bag into
said
chamber; actuating said means for extending said spike members and holding in
position
said loaded bags with the spike members from the spike star wheels assembly;
actuating
said cutting means that slit open the loaded bag with the cutting performed on
three sides
of the bag; rotating said star wheels assembly shaft in the conveying
direction, when
holding steady the bottom of the bag by the spike members, while drawing the
bag
around the star wheels assembly, wherein the bag is turned inside out and the
material
inside the bag is discharged by gravity; sifting the material from the bag;
and compacting
the emptied bag.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic side elevational view of a preferred embodiment of
automatic bag slitter according to the invention;
Figures 2, 3, 4 and 5 are schematic side elevational views suggesting the
sequence of operation of the automatic bag slitter from feeding, slitting and
product
discharge to slitting and compaction;
Figure 4A is an enlarged view of the right hand side of figure 4, showing
an alternate embodiment of the invention with the grate beneath the star
wheels assembly
comprising a pressurized air outflow cleaning means;
7
CA 02741247 2011-05-27
,
Figure 4B is an enlarged perspective view of this air outflow cleaning
means;
Figure 6 is an exploded view of selected components of the present bag
slitter;
Figure 7 is a perspective view of the spike star wheels assembly forming
part of the present invention;
Figures 8 and 9 are plan views of a single star wheel from the star wheels
assembly, sequentially showing the radially outwardly mounted spike movement
during
one complete rotation cycle of the star wheels assembly;
Figures 10 and 10A are perspective views from two different perspectives
of the spike bar assembly;
Figures 11 and 11A are perspective views of an electrical and a pneumatic
type motor, respectively, and rotating blade cutting assembly for two bag
cutter station
embodiments of the invention;
Figure 12 is a view similar to figure 7, but modified to more clearly show
the present invention cam design;
Figures 13A and 13B are schematic perspective and side elevational views
respectively of a first embodiment of the guide bar assembly of the invention;
Figure 13C is a side elevational view of a second embodiment of guide bar
assembly;
Figures 14 and 15 are views similar to figure 7, but further showing same
in context into the present automatic bag slitter housing in partly broken
perspective
view, the spike star wheels assembly being shown in its operative condition
inside the
machine housing in figure 14 and in its inoperative maintenance accessible
condition
outside the machine housing in figure 15;
8
CA 02741247 2011-05-27
Figure 16 is a view similar to figure 11, but further showing the spring
means biasing the knife assembly support arm;
Figure 17 is an elevational end view of the components of figure 16;
Figures 18A to 18E sequentially show in plan view how the spring biased
knife assembly pivot arms pivot during passage of a bag G through the cutting
section A; and
Figures 19A to 19E are views similar to figures 18A to 18E, respectively,
but in elevational views.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
INVENTION
Referring to FIGS. 1 to 5 of the drawings, it will be seen that full bags G
(containing powder or granular material) to be opened and emptied are fed into
the
automatic bag slitting machine 20 by an infeed roller conveyor C, which
transfers them to
a spiked star wheels assembly 22, which carries them through a cutting
station, generally
indicated at A, and to an emptying station, generally indicated at B. Precise
positioning
and orientation of the bags on conveyor C and of star wheels assembly 22 is
not required
as will become apparent hereinafter. At the cutting station A are two
rotatable cutting
blades or discs 24 and 26, disposed in a common horizontal plane and mounted
for
rotation on vertically extending shafts 28 and 30 respectively, rotatably
driven in direct
drive by motors 40, 42, respectively. Motors 40, 42 are preferably pneumatic
(air driven),
while not excluding as alternate embodiment electric motors 40', 42' (fig 11),
and are
carried by L-shape arms 44 and 46 for relative movement about bearing mounts
34, 36,
journaled into a registering wall section of the large housing 32 (figures 14-
15) enclosing
the present machine components. Pneumatic type motors 40, 42, are preferred,
in
particular in case the bags G enclose foodstuff or hazardous (e.g.
inflammables or
explosives) powder or granular material.
9
CA 02741247 2011-05-27
Conveyor C has an inner portion, extending into the machine housing 32,
and an external portion, extending outwardly from the machine housing 32. As
illustrated, the downstream end portion of bag conveyor C comes in generally
vertical
register with the overhanging cutting station A, closely spaced from the top
section of
star wheels assembly 22. Also, downstream cutter 26, 42, comes in vertically
overhanging register with the top surface of star wheels assembly.
Arms 44 and 46 are free to turn about the axes of the bearing mounts 34, 36.
The arms
44 and 46 are urged inwardly and rearwardly by resilient tension spring means
400 (see
figures 16 to 19E, and as generally disclosed in prior art US patent 4 504
183, supra), to
position the cutting discs 24 and 26 substantially centrally of the path along
which the
bags G are conveyed by the conveyor C and star wheels assembly 22. Tension
spring
means 400 preferably consists of piano wire, air cylinder, or gas spring
means. Spring
means 400 keep knife pressure on the bag G as the bag advances through the
cutting
station A, wherein the knives 24, 26, cut the bag G. As bag G clears cutting
area A,
spring means 400 bring cutters 24, 26 into their initial unbiased condition of
figure 2, in
spring back fashion. Most importantly, one of the support arms, here 46, is
positioned
downstream of the other (upstream) arm 44, for reasons which will be discussed
hereinafter.
Referring now to FIGS 7 and 10, it will be seen that the star wheels
assembly 22 is formed from a number (for example six) of transversely
extending star
wheels 60, 60A, 60B, ... transversely journaled by a single shaft 62. Two
anchor plates
61, 61A are transversely fixedly secured to opposite ends of shaft 62 spacedly
from the
star wheels. Shaft 62 is supported at opposite ends by bearing mounts 63 on
two opposite
upright walls 32A, 32B (fig 15) of the present machine housing 32 enclosing
the
controlled environment bag cutting chamber 67.
Shaft 62 is directly driven by a gear reducer motor 66 (figures 7 and 15).
Each star wheel 60, 60A, ... is rotatable with shaft 62 and a few (for example
five)
radially outwardly opening notches 68, 70, 72, ... are formed radially
outwardly of each
discoid star wheel 60, 60A, ... Each of the notches 68 of star wheels 60,
coaxially
register with one registering notch 68 for each of the other star wheels 60,
60A, so that a
CA 02741247 2011-05-27
spike bar 74 can extend transversely through all star wheels 60 axially of
notches 68 and
generally parallel to star wheel shaft 62. Thus, corresponding number of spike
bars 74
engage corresponding sets of notches 68. Spike bars 74 are rotatably carried
at opposite
ends into cavities 75 made in the anchor plates 61, 61A. A number (for example
four)
arcuate spikes 76, 76A, 76B, ... are integrally carried in lengthwisely spaced
fashion to
each spike bar 74. Spikes 76 are sized to fit in the spacing gap between each
corresponding successive pair of star wheels 60, 60A, ... and to be rotatable
independently of the star wheels between a first limit position, nested within
this inter
star wheel gap and thus clearing the radially outward periphery of the star
wheel (steps 4
and 5 of figure 9) and a second limit position (steps 1 to 3 of figure 9)
where the elbowed
sharp edge tip portion thereof 77 projects radially outwardly of the star
wheel 22. The
leading tip portion 77(figs 8-9) of the spikes 76 is directed toward the bag
conveying
direction.
To the outer end of each spike bar 74 is transversely mounted a lever 81
(figs 10, 10A). Lever 81 carries a cam roller 80 opposite spike bar 74. In an
alternate
embodiment, cam roller 80 is replaced by a cam follower (not shown). Spike bar
74 is
provided endwisely with a cam roller 80, it is rotatable independently of and
relative to
star wheel 60. Cam means 83 are formed by the interplay of lever 81, cam
roller 80 and a
female cam groove 65 in anchor plate 61.
It is understood that cam means 83 allows the elbowed sharp tip portion 77
of spikes 76 to spring outwardly to impale the bags at the downstream end of
the star
wheels assembly 22.
The automatic bag slitter 20 is designed to slit open and empty full bags G
containing different types of material, in particular granular or powder
material, food,
feed, chemical and other product, hazardous or non-hazardous, explosive or non-
explosive, packaged in paper bags, plastic bags, polywoven bags, burlap bags,
jute bags
and other packages in bags or boxes.
As shown in figures 2 to 5 of the drawings, the sequence of operation of
the present machine is as follows:
11
CA 02741247 2011-05-27
a. feeding
An operator loads the full bags G (loaded with powder/granular material)
onto the infeed conveyor C which convey the loaded bags to the spike star
wheels
assembly 22, where the bags are spiked and held in position during the
slitting cycle.
b. slitting
The two rotary cutting blades 24, 26, automatically adjust to the different
full loaded bag sizes and neatly slit the full bag G on three sides for a
thorough gravity
discharge of the product content thereof inside the bag.
c. product discharge
The bottom of the emptied bag, G', is firmly held by the spikes 76 and is
drawn around and under the spike star wheels assembly, in one long sheet. In
the
process, the empty bag G' is turned inside out and the product P is discharged
by gravity.
Empty bag G' engages a bag separation guide rocker 110 (fig 13A), which starts
to tilt in
a downstream downwardly oriented direction.
d. Sifting and compaction
Any remaining residue of product P accidentally clinging to the interior
surface of
the envelope of emptied bag G' is removed by a blast of air jet from a
pressurized air
source (not shown). Oversized foreign particles are sifted on a fine mesh
screen S (fig 6)
in the collection hopper 112, which is preferably vibrated at high frequency.
Spikes 76,
76A, ... are retracted and the emptied bag G' extruded via the compactor into
a dust-free,
plastic waste receiving bag. Bag separation guide rocker 110 tilts away about
pivot 111
from spike star wheels assembly 22, guiding spent bag G downwardly along the
downstream and bottom quadrant periphery of the star wheels assembly 22,
clearing the
top mouth 112A of hopper 112, toward an empty bag collector compactor chute
118
equipped with an endless screw 120 powered by motor 121(located outside of
chamber
32) for remote reclaim.
12
CA 02741247 2016-10-19
. ,
More particularly, in use, bags G are fed by the infeed conveyor C
towards the rotatable star wheels assembly 22. As successive rows of spikes
76, 76A,
approach the underside of bags G so conveyed, the spikes they are radially
outwardly
tilted by disengagement of the cam rollers 80 from the female cam groove 65 to
impale themselves through the bag G under the action of torsional springs (not
shown)
and carry the bag forwardly through the cutting station A. Alternately, the
position of
male/female cam rollers 80/grooves 65 could be inverted, without affecting the
scope
of the present invention.
The bag G thus encounters the upstream cutting disc 24 which penetrates
the bag envelope and which is then forced laterally by continued progress of
the bag G
to cut half of the leading edge of the bag and down one side of the bag.
Shortly
thereafter, the upstream cutting disc 24 has begun to move laterally, the bag
G is
brought into engagement with the downstream cutting disc 26 at precisely the
same
position as the upstream cutting disc 24 first contacted the bag. In similar
manner, the
downstream cutting disc 26 is forced forwardly and laterally by continued
progress of
the bag to complete the cut through the leading edge of the bag and down the
other side
of the bag. As the bag G' reaches the downstream quadrant portion of the
spiked star
wheel assembly 22, the lowermost portion of the envelope of the bag which is
securely
impaled on the spikes 76 is pulled downwardly from the remainder of the bag G'
which
is supported as it is fed over the star wheels assembly before it is drawn
downstream to
follow the lower part of the bag by a rocker type bag separation guide bar
assembly 110
spacedly overlying a collection hopper 112 into which the contents of the bag
fall. The
envelope of the bag G' is conveyed by the spiked star wheels assembly 22. The
bag
envelope is conveyed downstream and released from the spiked star wheels
assembly 22
by retraction of the spikes 76, to fall into bag collection chute 118 equipped
with
powered endless screw 120 which serves to compact and convey the empty bag G
to
suitable disposal means, such as a collection sack or the like.
Since the length of the empty bag G' where it is removed is twice that of
the uncut bag, the infeed conveyor C is arranged to run at such an adjustable
speed as to
be suitable for different applications/constructions/configurations of the bag
G' to match
13
CA 02741247 2011-05-27
the star wheels assembly 22, whereby the machine will be able to handle,
without
interruption, a continuous supply of bags from the infeed conveyor C.
The cutter station shafts 28 and 30 are preferably adjustable as to height
relative to the arms thereof 44 and 46, to enable the machine to be set up to
deal with
bags of different size. Clearly, the cutting discs 24 and 26 should always be
at the same
horizontal plane level to ensure that they each engage the bag G in turn at an
identical
position to ensure a continuous cut around the bag, facilitating the full
emptying of its
contents as the undersurface of the bag envelope is peeled from the remainder
at the
emptying station.
Figure 7 shows the present improved spike conveyor assembly comprising
the following features:
-
the series of star wheels 60 manufactured out of plastic or sheet metal,
aligned in
series and the drive shaft 62 axially carrying all of these star wheels;
-
The two anchor plates 61, 61A transversely carrying the opposite ends of the
spike bar 74, wherein five or more spike bars 74 are used and anchored by the
two
anchor plates 61 on both opposite ends thereof;
- The drive shaft 62 carrying the entire spike star wheels assembly 22 is
driven
directly by a gear reducer motor 66. There are no nuts, bolts, gaskets or
belting
material used anywhere in the spike star wheels assembly, which is exposed and
in direct contact to the product;
- such a design is especially designed for food, feed, chemical or other
powder or
granular product which is packaged in any form of bag.
Figures 8 and 9 illustrate the travel path of a single spike 76 as the star
wheels assembly 22 rotates with its shaft 62 through one full turn by going
through four
successive quadrants of the star wheels assembly. The improved automatic bag
slitter 20
is strictly based on the engineering theory explained below. This theory
applies to the
spike star wheels assembly 22 and its operation through one complete rotation
and the
repeatability function for continuous operation with minimal expected
downtime. The
14
CA 02741247 2011-05-27
spike movement during one complete rotation cycle of the star wheels assembly
22 is
schematically shown in these figures.
The spike star wheels assembly 22 rotates clockwise using its shaft 62 as
the centre point; the spike bars 74 and their orbital path follow arrows ABC
(spike shaft
assembly travel) as shown in figure 9. The cam rollers 80 (figs 10, 10A)
engage and
follow the stationary groove or female cam, 65, in anchor plates 61, and
provide the
trajectory for the travel of spike sharp elbowed tip 77.
The sequence is as follows:
- Step 1: the spike bar 74, during its travel in the fourth upper
downstream quadrant
of star wheels assembly 22 as shown above, penetrates into the bag G by
rotating
on its own axis. The driving force is provided by the cam action of cam means
83
(components 80, 81, 65).
- In an alternate embodiment of the invention, an external torsional spring
(not
illustrated) can also be used instead of/or in combination with the cam means
83.
During this time, the bag G is spiked and held in position during the slitting
cycle.
- Step 2: the spikes 76 retain their position from a 12 o-clock position to
a 3
o'clock position via the same upper downstream quadrant of star wheels
assembly
22. During this time, the rotary cutting blades automatically adjust to
different
bag sizes and neatly slit open the bag on three sides only for a thorough
gravity
discharge of the product. The spikes 76 hold the bottom half of the bag during
the
product separation and discharge from the bag.
- Step 3: the spikes 76 retain their position from a 3 o'clock position to
a 6 o'clock
position in lower downstream quadrant of assembly 22, without turning on their
own axis 74, during which time the bottom of the bag G' is firmly held by the
spikes 76 and is drawn around under the spike star wheels assembly 22 in one
long sheet. In the process, the bag is turned inside out and the product is
discharged by gravity.
- Step 4: the spikes 76 turn on their own axis 74 and retract radially
inwardly back
in from the star wheels assembly 22 and release the empty bag for compaction
or
disposal in the third lower upstream quadrant of assembly 22. It should be
noted
CA 02741247 2011-05-27
that the star wheels assembly 22 top tangential surface is then used as a
support
base while the spikes 76 are retracted.
- Step 5: in the upper upstream quadrant of star wheels assembly 22,
the cycle of
extension/retraction of spikes 76 is repeated, and continue for the next full
turn.
In figure 10, it is understood that in the improved spike bar assembly, the
spike bar 74 is a rod or a bar or a tube. Spikes 76 project radially outwardly
from bar 74,
and are welded to the rod 74 or bar or tube. At one end of the bar 74, lever
81 carries
cam roller 80. Inside the machine 20, only the spikes 76 and the spike bar 74
are
exposed, thus there is no hardware used. Inside the machine 20, the spike bar
74 is
totally washable. The bar 74 could also be made out from plastic or polymer
and/or other
metal.
In figures 11-11A, the improved knife assembly comprises an electric motor 40,
42, mounted directly to the knife arm 44, 46. According to an alternate
embodiment of
the invention, donuts may be used to follow the contour of the full loaded
bags.
Alternately, and preferably, pneumatic (pressurized air) driven motors 40',
42', may be
used (replacing electric motors 40, 42). The entire system is completely
washable. The
system is safe enough to be usable for food grade applications, although non
foodgrade
applications are not excluded.
In the improved cam design of figure 12, the cam means 83 is made from cam
roller 80, lever 81, and a female cam or groove 65 made in fixed anchor plate
61. Cam
means 83 projects outside of the bag cutting and emptying chamber inside the
housing 32
enclosing the bag slitting and emptying chamber 20. Cam means 83 is thus an
integral
part of the spike star wheel assembly 22, but externally located relative to
the controlled
environment bag cutting and emptying chamber 32. The (male) cam rollers 80
thus
engage and follow the (female) cam groove 65 and provide a full rotational
capability.
All of the cam assembly 83, is entirely located outside of the bag slitting
and emptying
chamber, and thus provide a completely safe food grade environment for food
applications if required, without the hazard of accidental food product
contamination
when the bag is opened.
16
CA 02741247 2011-05-27
In an alternate embodiment of the invention, torsional springs (not shown) may
be
used to drive the spike in addition to/or as a replacement of the force given
by the path of
the cam means 83.
The improved guide bar assembly 110 shown in figure 13A, is one single
complete component manufactured without any hardware or springs. A rocker bag
separation guide bar 111 is pivoted at the opposite upright walls 32A, 32B of
the machine
housing 32. A flat grate 114 is fixedly mounted to pivotal guide bar 111 by
two pairs of
opposite inversely V-shape brackets 116, 118. The whole guide bar assembly 110
can be
removed very easily from housing 32, and cleaned and washed. Guide bar
assembly 110
is preferably manufactured out of carbon steel, stainless steel, or
plastic/polymer; and out
of tubing, bars or rods. Grate 114 includes an upstream elongated hollow tube
115
having a number of lengthwisely spaced bores 115A. A pressurized air source is
fluidingly connected to tube 115, for providing air outflow at F. Air flow F
cleans
passing bags G, as suggested in figure 4.
In the alternate embodiment of guide bar assembly 150 of figures 13A, 14 and
15,
a flat grate member 152 is supported by two opposite L-shape brackets 154,
156, these
brackets 154, 156 being pivotally mounted to opposite pivot mounts in upright
walls
32A, 32B of the machine controlled environment bag cutting machine chamber
housing
32.
Figures 14 and 15 suggest that for foodgrade application at cleaning mode of
the
star wheel assembly 22, this modular spike star wheel assembly can be slid
outwardly of
the machine controlled environment housing 32 for inspection, maintenance and
cleaning, along a telescopic support sliding rack 300. Rack 300 includes a
stationary
portion 302, permanently mounted inside housing 32, and a telescopically
extendable
portion 304, movable from a first limit position overlying the stationary
portion 302, to a
second limit position fully or almost fully extended outwardly from housing
32, for
maintenance access.
17
CA 02741247 2011-05-27
Preferably, dust filter means are provided about access areas of the
machine housing 32, to enhance atmospheric control of air borne contaminants
of the
controlled environment bag slitting chamber.
It is therefore understood that the components inside of the machine are
designed to be modularly mounted therein: the infeed conveyor C, the spike
star wheels
assembly 22, the rocker bag separation bar assembly 110 or 150, and the cutter
assembly
A. All of these modular components are easily removable manually without
tools, for
cleaning and general maintenance.
The inside of the machine housing 32 also preferably meets the clean-in-
place (CIP) standard.
The empty bag compactor 118, 120, may also slide out of the machine
housing 32 in the same way as the spike star wheels assembly 22. The integral
dust filter
may be modular, with the filter cartridge being easily removed.
It will be appreciated that as we do not intend to limit the invention to the
above examples only, many variations, such as might readily occur to one
skilled in the
art, being possible, without departing from the scope thereof as defined by
the appended
claims.
For optimal operation of the present bag opening and slitting machine, the
weight
load of powder/granular material inside the full bag G should most preferably
range
within approximately 5 to 250 pounds.
It is noted that each or some of the star wheels 60, 60A, 60B, ... of star
wheels
assembly 22 could be replaced by any other suitably designed disc-like or drum
like
element or object, hollow or solid, while remaining well within the scope of
the present
invention. However, a drum like star wheel element would not be optimal in
view of the
requirement of guaranteeing a contamination free environment inside the bag
opening
and slitting machine of the present invention.
18
