Bag discharge apparatus

A tie 24 seals an outer bag 26 and an inner line bag 28 of a container. The inner liner bag 28 is fed into a tubular discharge chute 30 and the tubular end of the outer liner bag is passed over the outside of a chute 30 to extend over an inflatable seal 32. Then two opposed pinch bars 34 on either side of the container, just below the tie 24, are actuated by pneumatic cylinders 36 to move towards each other and to pinch the inner and outer bags 26 and 28 just below the tie. Then a seal 32 is inflated to urge the seal against the inner face of the outer bag. Then the tie 24 is removed and the pinch bars are retracted before moving the chute 30 downwardly by retracting pneumatic cylinders 38 to take the lower end of the outer bag downwardly.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
The present invention relates to bag discharge apparatus and means for 
discharging a bag. 
Previous machines for discharging flexible bulk containers comprise 
supporting the bulk container over a discharge chute sealing the neck to 
the discharge chute and untying a neck at the bottom of the container to 
allow material to flow out of the container through the discharge chute. 
However, the neck of the container is often narrow and the neck can tend 
to stay bunched up once the neck is untied and impede the effective 
discharge of material. This is particularly the case where a thin 
extremely flexible and disposable liner bag is located within a heavy 
reuseable outer bag. 
Previous bag discharge machines have also suspended the bag from a support 
frame with the frame then being supported on spring biased poles and with 
the bottom of the bag being partially supported on a conical plate. As the 
weight of the bag on the support frame decreases during discharge spring 
means acting on the poles biases those poles and the frame support 
upwardly to assist in lengthening the main extent of the bag and allowing 
the bag base to drop downwards and therefore assist in causing material to 
leave the bag. However, the spring means are dependent upon the weight of 
material in the bag and, as that weight slowly decreases, the spring means 
slowly raises the bag to a limited extent and in a gradual manner. 
Furthermore the material in the bag can lock the base of the bag in 
position to act to stop the springs effectively raising the bag base 
thereby adversely affecting discharge. Accordingly, material can still 
tend to remain stacked up within the container without being effectively 
and smoothly discharged. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to attempt to overcome at least 
some of the above described disadvantages. 
According to one aspect of the present invention bag discharge apparatus 
comprises means to support a bag over a discharge opening, means to engage 
the lower region of a bag, and means to move the lower region of a bag 
downwardly relative to an upper region of the bag. 
By causing such relative movement of the lower region of a bag, the lower 
region is pulled open to ensure discharge. 
The means to move the lower region of a bag downwardly relative to an upper 
region of a bag may be arranged to occur before or during discharge of 
material from a bag. 
The discharge apparatus may include means to at least partially support a 
lower portion of a bag with the means to engage the lower region of a bag 
being beneath the means that provides partial support for a lower portion 
of the bag and the relative movement may be arranged to be between the 
means to at least partially support the lower region of a bag and the 
means to engage the lower region of a bag. The means to at least partially 
support a lower portion of a bag may include an opening through which a 
part of a bag may extend downwardly to the lower region of a bag. 
The means to engage the lower region of a bag may comprise a means to seal 
with a bag, such as an inflatable seal. The means to seal with a bag may 
be arranged to seal with the inner surface of the bag. The means that are 
arranged to engage the lower region of a bag may include a discharge chute 
that is arranged to move with the means to engage the lower region of a 
bag when the relative movement occurs. 
The apparatus may include clamping means arranged to engage a portion of a 
bag at a higher elevation than the region where the lower region of a bag 
is arranged to be engaged. The clamping means may comprise opposed pushers 
that are movable towards each other to engage opposed sides of a bag. The 
clamping means may be arranged to be located between the means that are 
arranged to engage the lower region of a bag and the means that are 
arranged to at least partially support a lower portion of the bag. 
The apparatus may include means arranged to move the lower region of a bag 
upwardly relative to an upper region of a bag after discharge of the 
contents of a bag. 
The present invention also includes a method of discharging a bag 
comprising locating a bag to be discharged over a discharge opening, 
engaging the lower region of the bag and moving the lower region of the 
bag downwardly relative to an upper region of the bag. 
The method may comprise causing the relative movement prior to or during 
discharge of the contents of the bag commencing. 
The method may comprise at least partially supporting a lower portion of a 
bag and causing said relative movement between a region of a bag lower 
than the at least partial support for the lower portion of the bag and the 
lower region that is engaged. 
The method may comprise engaging the lower region of a bag with a seal, 
such as an inflatable seal, before causing the relative downwards 
movement. 
The method may comprise locating the bag over a discharge opening and then 
engaging the lower region of the bag and then releasing a tie that retains 
the contents within the bag and then causing the relative downwards 
movement of the lower region of the bag. The method may comprise clamping 
the bag prior to releasing a restraint that retains the contents of the 
bag. 
The method may comprise moving the lower region of a bag upwardly relative 
to an upper region of the bag after discharge. 
According to a further aspect of the present invention bag discharge 
apparatus comprises support means for an upper region of a bag arranged to 
at least partially support a bag over a discharge opening and actuator 
means arranged to move the upper region of a bag upwardly relative to a 
lower region of the bag. 
Thus the actuator means are able to move the upper region of a bag 
upwardly, when desired. 
The apparatus may be arranged to move the upper region of a bag upwardly 
relative to the lower region from a first position to a second 
predetermined position. Either or both of those positions may be 
adjustable. The apparatus may be arranged to cause the relative movement 
from the first position to the second position, and then to a third or 
more position or positions. 
The actuator means may be arranged to move the upper region of a bag 
upwardly relative to a lower region upon sensing of a predetermined 
condition such as the weight of material remaining in the bag or the 
duration that the bag has been discharging from or the level within the 
bag. 
The actuator means may be arranged to move the upper region of a bag 
upwardly relative to a lower region of the bag when the bag is 
approximately one third full. 
The actuator means may be hydraulically or pneumatically actuated. 
The actuator means may be arranged to move the upper region of a bag 
upwardly away from the support means that have previously provided support 
for an upper region of the bag. 
According to a further aspect of the present invention a method of 
discharging a bag comprises at least partially supporting a bag over a 
discharge opening and subsequently actuating means to move the upper 
region of the bag upwardly relative to the lower region. 
The method may comprise moving the upper region of the bag from a first 
position to a second predetermined position. 
The method may comprise sensing the weight in the bag and then actuating 
the actuator means to move the upper region of the bag upwardly in 
response to the sensed weight. 
The method may comprise moving the upper region of a bag off the support 
that initially at least partially supports the upper region of the bag 
when the upper region of the bag is moved upwardly relative to the lower 
region. 
According to another aspect of the present invention bag discharge 
apparatus comprising a support for a bag having a generally quadrilateral 
cross-section when viewed in plan also comprises reciprocatable pushers 
arranged to move inwardly to, in use, urge a portion of the periphery of a 
bag inwardly, each pusher also being arranged to move outwardly is 
characterised in that the pushers are arranged to act on what, in use, 
will be a corner region of a quadrilateral bag. 
The pushers may be arranged to act from one corner region such that, when 
moving inwardly, the pusher moves generally towards what, in use, will be 
an opposed corner region of the bag. 
The pushers may be arranged such that a first pair of opposed corners of a 
bag are arranged to move inwardly and outwardly simultaneously and the 
pushers may be arranged such that a second pair of opposed corners 
different from the first pair are arranged to move inwardly and outwardly 
simultaneously. The pushers on the first pair of corners may be arranged 
to move inwardly when pushers on the second pair of corners are in an 
outer position and vice versa. Alternatively or additionally pushers may 
be arranged to act on each corner to move all corners inwardly 
simultaneously. 
Each pusher may include a first portion arranged to act along one side of a 
bag, a second portion arranged to act along a second adjacent side of a 
bag and a third portion extending between the first and second portions 
arranged to act on the corner region of a bag. When all pushers are in an 
inwards position they may define, in plan, a generally eight sided 
restriction. 
Each pusher may be arranged to cause a corner portion of the bag to move 
inwardly through a greater extent than the adjacent side portions of a 
bag. 
The present invention also includes a method of discharging material in a 
bag, which bag has a generally quadrilateral cross-section when viewed in 
plan, the method comprising causing pushers to reciprocate inwardly to 
push a corner region of a bag inwardly with each pusher also being movable 
outwardly. 
The pushers may be arranged to move inwardly simultaneously, or separately 
from each other, or in opposed pairs. The method may comprise moving 
pushers acting on each corner inwardly to be at an inner position after 
partial discharge of material from the bag and the pushers may remain in 
that inner position throughout the remainder of the discharge of material 
from the bag or the pushers may be retracted and possibly further 
reciprocated after they have all been at an inner position. 
According to another aspect of the present invention bag discharge 
apparatus includes a support for a bag, with the bag having an outlet 
located at the bottom thereof, the apparatus including first pushing means 
arranged to urge the side wall of the bag inwardly and arranged to act on 
the bag at one elevation and second pushing means arranged to urge the 
side wall of a bag inwardly at a lower elevation than the first pushing 
means. 
The second pushing means may be arranged to also push the wall of the bag 
upwardly when the wall of the bag is moved inwardly. 
The first pushing means may be arranged to act on the corner region or 
regions of the bag. 
According to another aspect of the present invention in a method of 
discharging a bag containing material in which the bag is located such 
that an outlet of the bag extends downwardly, the wall of the bag is 
caused to move inwardly at one elevation by a first pushing means and 
inwardly at a second, lower elevation by second pushing means. 
The sides of a bag at different elevations may be arranged to be urged 
inwardly at the same time or at different times. 
The method may comprise urging corner regions of the bag at the first 
elevation to move inwardly, either simultaneously or sequentially or in 
pairs with the walls of the bag at the lower elevation being caused to 
move inwardly either at the same time as the walls at the upper elevation 
or at a different time. 
The walls of the bag at the second elevation may be arranged to move 
upwardly at the same time that they are moved inwardly. 
According to a further aspect of the present invention bag discharge 
apparatus includes a support for a bag from which bag material is arranged 
to be discharged from an outlet at the lower region of the bag, the 
support being arranged to suspend such a bag and the apparatus further 
including abutment means arranged to be engaged by the support when the 
support is moved in a generally horizontal direction such that the support 
is arranged to accurately suspend the bag in the required position on the 
apparatus. 
The support may be arranged to engage the abutment means to locate the bag 
in a lateral horizontal direction or in the correct angular position, when 
viewed from above, or both. 
The abutment means may comprise two spaced members or upwardly extending 
means or both. 
The present invention also includes a method of aligning a support for a 
bag suspended therefrom with a bag discharge apparatus comprising moving 
the support in a lateral direction such that the bag engages abutment 
means to accurately align the support for the bag, and therefore the bag 
that is suspended therefrom in position over the machine. When the bag is 
moved into contact with the abutment means the bag may be arranged to be 
restricted from further lateral movement, when viewed from above, and may 
be caused to turn upon engagement with the abutment means to correctly 
align the support means, and therefore the bag in an angular position, 
when viewed from above. 
The present invention includes any combination of the herein referred to 
features or limitations. 
The present invention can be carried into practice in various ways but one 
embodiment will now be described, with reference to the accompanying 
drawings in which:

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE 
The container 12 shown in FIG. 2 is suspended from spaced parallel bars 16 
(only one of which is shown) which are connected together by spaced 
parallel bars (not shown) that extend inwardly of and perpendicular to the 
bars 16. Prior to the container being located over the emptying apparatus 
the container is rigged on to the frame comprised by the bars by passing 
four loops 18 over each protruding end of the bars 16. A fork lift truck 
or hoist then engages the frame by the forks extending under the frame 14 
between two opposed pairs of loops 18 with the fork then being raised to 
support the frame with the container 12 being suspended from the frame. 
The container is then moved to locate the container over the apparatus 10 
before the fork lift or hoist support is lowered to locate the bars 16 on 
support poles 20 of the emptying apparatus or on pneumatic lift cylinders 
22 the purpose of which will be described later. 
As shown in FIG. 8, the top of the frame may have a pair of spaced upwardly 
extending arms 50 (only one of which is shown). When the frame is swung 
over the apparatus by a hoist the bars of the frame can contact the arms 
50 to cause one of the bars 16 to swing around until it abuts both arms 50 
to accurately locate the frame and the suspended bag in position over the 
discharge chute. 
The frame is then in the position shown in FIG. 3 with the container being 
suspended from the frame and with the lower portion of the container 
resting on a conical support plate 23 having a central lower opening 25. 
The lower end of the container, which converges in a downwards direction to 
a tubular neck, extends through the opening 25, downwardly, to a tie 24 
that seals the outer bag 26 and an inner liner bag 28 of the container. 
The inner liner bag 28 is fed into a tubular discharge chute 30 and the 
tubular end of the outer liner bag is passed over the outside of the chute 
30 to extend over an inflatable seal 32. 
Then two opposed pinch bars 34 on either side of the container, just below 
the tie 24, are actuated by pneumatic cylinders 36 to move towards each 
other and pinch the inner and outer bags 26 and 28 just below the tie. 
Then, as shown in FIG. 4, the seal 32 is inflated to urge the seal against 
the inner surface of the outer bag 26 in the region of its free end to 
hold and seal with that bag. 
Following the holding and sealing of the outer bag the tie 24 is removed 
and the pinch bars are retracted before moving the chute 30 downwardly by 
retracting pneumatic cylinders 38 that are connected to a plate 40 that is 
fast with the chute 30. The chute 30 is then in the position shown in FIG. 
5 in relation to an angled discharge chute 32. Alternatively the chute can 
be lowered during discharge, if desired. 
In the position shown in FIG. 5 the lower end of the outer bag is stretched 
or pulled down to allow free discharge through the lower part of the 
narrower inner and outer bags without the outer bag tending to bunch up 
and impede the smooth discharge flow through the inner bag. 
The apparatus is also provided with four corner massage cylinders 44 
secured to a side support frame 45. The height of these corner massagers 
is adjustable possibly by reversing the orientation of the frame 45. Each 
cylinder 44 includes a pusher plate 46 that is caused to urge the corners 
and sides of the bag repeatedly inwardly before being retracted to massage 
the lower part of the container during discharge and to prevent material 
from clogging in the narrower discharge area of the bag. 
The corner massage cylinder 44 are shown more clearly in FIG. 10. Each 
plate 46 is movable from a first outer position to a second, inner 
position. The four plates are shown as 46A to 46D. The sequence during the 
majority of the discharge is for the plates 46A and 46C to be moved in and 
then, after retraction of those plates, for the opposing plates 46B and 
46D to be moved in and so on. 
When the bag is low in level, possibly after the top of the bag has been 
raised, all four pusher plates are moved inwardly simultaneously. The 
plates can either be held in that position during the remainder of the 
discharge or subsequently they can be moved out or they can resume their 
reciprocation. It can be seen from FIG. 10 that each plate includes a flat 
central extent and two end portions that extend parallel to the sides. 
These ensure that any material in the corners is dislodged during 
discharge and that the sides of the bag are also moved in to a 
considerable extent during massage. 
The apparatus is also provided with two opposed side pushers 52 that are 
pneumatically operated to push upwardly and inwardly on the base of the 
bag just above the neck of the bag. These pushers 52 can operate after the 
corner pushers have each been pushed in or out or in any relative 
sequence. 
When the container is approximately two thirds empty the frame 14 is raised 
by actuating the hydraulic or pneumatic lift cylinders 22 to move the bars 
16 upwardly, as shown in FIG. 6. This movement may directly lift the frame 
or may raise the frame off the poles 20. This movement straightens out the 
sides and base of the bag and pulls any material that may be locked in the 
corners out. As it may be a relatively quick movement, this will cause any 
build up of material in the lower region of the bag or adjacent to the 
side walls of the bag to be displaced and discharged. Alternatively the 
movement can be gradual. 
The apparatus can be used with bags of different heights by making the 
starting and finishing points of the cylinders adjustable. The cylinders 
may be arranged to raise the bag in steps such as by arranging for two 
cylinders in parallel to effect the lifting. 
The raising of the upper region of the bag may be arranged to occur when a 
predetermined level remains in the bag, after a predetermined period of 
discharge or when the weight of the bag reaches a predetermined value. 
Instead of cylinders to raise the upper portion screw jacks could be used 
with a linear motor actuator. 
As the neck of the bag is held at a low extended position, when the top 
frame is lifted by the actuators the bag will reduce in width and cause 
the lower corners of the bag to move in thereby causing any jamming or 
congestion of material in the lower region to be broken. The raising of 
the frame that supports the bag may lift the bag at least partially off 
the conical support 56 for the base of the bag. 
Bag massage with the pushers 34 continues until the bag is empty. When the 
bag is fully discharged the pushers 34 are retracted, the lift cylinders 
22 are retracted to lower the frame onto the poles and the neck 30 is 
raised by extending the pistons 38 and the pinch bars are applied. The tie 
on the container can then be replaced and the frame 14 can be engaged by a 
hoist or fork lift truck and raised to allow the frame and empty bag to be 
removed from the apparatus. Then a previously rigged container can be 
loaded and discharged as referred to above in order that the discharge 
apparatus is idle for the minimum time. 
The reader's attention is directed to all papers and documents which are 
filed concurrently with or previous to this specification in connection 
with this application and which are open to public inspection with this 
specification, and the contents of all such papers and documents are 
incorporated herein by reference. 
All of the features disclosed in this specification (including any 
accompanying claims, abstract and drawings), and/or all of the steps of 
any method or process so disclosed, may be combined in any combination, 
except combinations where at least some of such features and/or steps are 
mutually exclusive. 
Each feature disclosed in this specification (including any accompanying 
claims, abstract and drawings), may be replaced by alternative features 
serving the same, equivalent or similar purpose, unless expressly stated 
otherwise. Thus, unless expressly stated otherwise, each feature disclosed 
is one example only of a generic series of equivalent or similar features. 
The invention is not restricted to the details of the foregoing 
embodiment(s). The invention extends to any novel one, or any novel 
combination, of the features disclosed in this specification (including 
any accompanying claims, abstract and drawings), or to any novel one, or 
any novel combination, of the steps of any method or process so disclosed.