US3827471A

US3827471A - Flexible transporting containers

Info

Publication number: US3827471A
Application number: US00290108A
Authority: US
Inventors: G Gregory; D Benedict
Original assignee: FALSE CREEK IND Ltd
Current assignee: FALSE CREEK IND Ltd
Priority date: 1971-10-18
Filing date: 1972-09-18
Publication date: 1974-08-06
Anticipated expiration: 1991-08-06
Also published as: ZA727260B; GB1394226A; FR2156795A1; DE2250757A1; AU447234B2; AU4767672A; JPS4849582A; CA1013309A; ZM16672A1; SE377554B

Abstract

A container in the form of a tube-like bag open at the top and bottom and having a bottom section that can be folded over the lower end of the bag and up the side of the latter. Securing means releasably connects the folded-over bottom section to the side of the bag. The container can be rolled or folded up for storage and shipment, and it can be opened into tubular form and filled with particulate material through the upper end thereof. Release of the securing means when the bag is lifted up or suspended allows the bottom section to straighten out and the material to discharge from the container.

Description

United States Patent [19] Gregory et al.

[ FLEXIBLE TRANSPORTING CONTAINERS [75] Inventors: Gerald H. Gregory, Surrey, British Columbia; Donald W. Benedict, Beach Grove, British Columbia, both of Canada [73] Assignee: False Creek Industries Ltd.,

Vancouver, British Columbia, Canada [22] Filed: Sept. 18, 1972 [2]] Appl. No.: 290,108

[30] Foreign Application Priority Data [11] 3,827,471 Aug.6, 1974 Primary Examiner-Herbert F. Ross A tzorney, Agent, or F irm-Fetherstonhaugh & Co.; Kellard A. Carter 5 7] ABSTRACT A container in the form of a tube-like bag open at the top and bottom and having a bottom section that can be folded over the lower end of the bag and up the side of the latter. Securing means releasably connects the folded-over bottom section to the side of the bag. The container can be rolled or folded up for storage and shipment, and it can be opened into tubular form and filled with particulate material through the upper end thereof. Release of the securing means when the bag is lifted up or suspended allows the bottom section to straighten out and the material to discharge from the container.

8 Claims, 12 Drawing Figures FLEXIBLE TRANSPORTING CONTAINERS This invention relates to flexible containers for transporting material in particulate form, and particularly materials such as ore concentrates, cement, fertilizer, bentonite, iron pellets, and other materials that are shipped in bulk form.

This transporting container is particularly designed for heavy particulate material, for example, ore concentrates, and for the sake of convenience will be described herein relative to ore concentrates. However, it is to be understood that the transporting containers can be used for any particulate, granular, or bulk transportable material.

At the present time, a great amount of ore concentrate is transported by truck, rail, vessel and aircraft around the world. The methods by which these materials are handled and shipped have not changed substantially over the years despite the many known disadvantages of these methods.

Ore concentrates are shipped from the mine to the smelter. The ore may be transported directly to the smelter by one conveyance, but more often there are numerous changes of conveying vehicles. For example, the ore is often transported by truck to a rail head, by rail either to the smelter or to a tide water port from which it is transported to an overseas smelter. There are numerous problems involved in handling the heavy ore concentrates, abd losses due to spillage and dusting are great.

For example, a concentrate, such as copper concentrate, when transported from the mine to the smelter, rail head or port must be transported in specially constructed semi-trailer trucks. This is due to the fact that the concentrate is a very heavy material, and in order to achieve acceptable axle loadings, special trucks are used and the bodies thereof are usually constructed of aluminum in order to reduce the overall weight. A serious drawback with such vehicles is that they cannot be used to transport many materials which must be hauled back to the mine and, therefore, additional trucks must be used to transport mill equipment and supplies. As these second transports are not acceptable for the transport of concentrates, many of the trucks used carry payloads in one direction only.

When the trucked ore concentrate reaches its destination, it is dumped from the semi-trailer into a suitable receiver. This dumping process results in some additional loss. When the material is transported in a gondola or open rail car, there are additional losses. Losses in the total transportation systems have been reported as high as 1.5 percent. As the value of copper concentrate is something of the order of $250.00 per ton, the losses which occur between the mine head and the smelter can be serious. Furthermore, materials such as copper concentrate must be kept dry. When copper concentrate is rained upon the material can very quickly approach a slurry state which can leak out of the truck or railroad car, thereby increasing losses. More important, however, it becomes an extremely difficult material to handle. Concentrate with excessive moisture content should not be loaded in a cargo vessel because of its thixotropic characteristics which make it dangerous in the vessel hold.

There are numerous prior shipping containers in existence, but these are not completely satisfactory for use with heavy particulate material such as ore concentrates. Some of the difficulties are cost of the containers themselves, problems in rapid loading and unloading, strength of the containers and their ability to stand up under the prevailing conditions, and the problem and cost of returning empty containers to the source of the material to be transported.

The purpose of the present invention is to eliminate or greatly reduce the numerous problems set out above. A transporting container in accordance with this invention comprises a tube-like bag having a peripheral wall forming a main holding section, a tubelike bottom section aligned with and connected to a lower end of the bag wall, said bottom section being foldable over and across the adjacent end of the holding section and upwardly along the outer surface of the peripheral wall to close the end of the holding section, and releasable securing means co-acting between the bottom section and the adjacent peripheral wall of the holding section releasably to secure said bottom section and said wall together, whereby when there is particulate material in the holding section of the bag, the weight of said material pressing against the folded-over bottom section helps to seal the lower end of the bag and yet release of said securing means results in the bottom section straightening out and instant discharge of the particulate material when the bag is supported near the top thereof.

Although this container is in the form of a bag, it can be placed on a supporting surface, such as a pallet, the bed of a truck or rail car, a dock or a deck of a vessel, and it will remain upright. The particulate material within the container bag tends to shift downwardly and outwardly when the container is deposited on a surface so that it shapes the flexible bag into a relatively large substantially flat bottom. The weight of the particulate material tends to seal the lower end of the bag against any possible leakage, and also keeps undue strain off the securing means which is up the side of the bag.

The transporting container is usually loaded when it is supported at the top of the bag which is held open while the particulate material is poured into the bag. As the pouring continues, the bag swells out to its fullest extent while the weight of the material presses against the folded-over bottom section of the bag. The foldedover arrangement of the bottom section is such that much of the strain against the bottom section is taken by the peripheral wall of the bag. In order to unload the container, it is only necessary to release the securing means and, if necessary, to start the folded-over portion of the bottom section to swing downwardly, at which time the weight of the material in the bag tends to open up the folded bottom section so that the particulate material will flow freely through the open end of the bag. The securing means can be released while the bag is suspended in the air, or while the bag is resting on a support. In the latter case, the bag is raised to cause the bottom section to straighten out under the weight of the material. This in effect is lifting the bag '01? the material which stays on the support.

After the discharge of the particulate material, the bottom section can be folded over and secured to the peripheral wall of the bag, and the the container can be rolled or folded into a small bundle for return shipment and storage.

A very substantial advantage of this invention is the fact that ordinary vehicles can be used for transporting these containers, and these vehicles can be used to transport supplies back to the mine so that they are not running with a payload in one direction only.

The use of these flexible containers greatly reduces the losses associated with the normal transportation system, and this is a substantial benefit to the industry and offsets the cost of the containers, and helps to reduce air pollution caused bydust at numerous intermediate loading and unloading points and during transit. In addition, these flexible containers enclose and protect the product, thereby eliminating the necessity for large warehouses for storage purposes. At the present time, small lots of concentrates are not normally shipped, and the material must be stocked piled in a warehouse prior to being loaded in bulk. The use of these flexible containers makes it possible to load the particulate material as ordinary general cargo or as a partial load and, therefore, the large warehouse is not required.

Preferred forms of the invention are illustrated in the accompanying drawings, in which FIG. 1 is an isometric view of a transporting container in fully open condition,

FIG. 2 is a view similar to FIG. 1 with the bottom and top of the container closed, this being for illustrative purposes,

FIG. 3 is a side elevation of the empty container in partially collapsed condition and with the bottom section folded over almost to its final latched position,

FIG. 4 is a plan view of the container as shown in FIG. 3,

FIGS. 5 and 6 successively illustrate two stages of the closing of the top of the loaded container,

FIG. 6 being turned around relative to FIG. 5,

FIG. 7 is a diagrammatic view showing the loaded container resting on a flat surface,

FIG. 8 is a diagrammatic isometric view of the loaded container suspended from a crane or the like,

FIG. 9 is a view similar to FIG. 8 but showing the bottom section unlatched and moving towards the open position,

FIG. 10 is another view of the suspended container after the contents thereof have been discharged,

FIG. 11 is an isometric view of the upper end of a container having an alternative cover or closure arrangement, and

FIG. 12 is an alternative way of supporting the container during loading thereof.

Referring to FIGS. 1 to 10 of the drawings, 10 is a transporting container in accordance with this invention which consists mainly of a tube-like flexible bag 11 which has an open top 12 and an open bottom 13. Although bag 11 may have any desired cross-sectional shape, such as circular or oval, it is preferably substantially rectangular in cross-section when empty, as clearly shown in FIGS. 1 and 2. Bag 11 has a peripheral wall 16 which is made up of opposed plain front and

back panels

17 and 18, and opposed inwardly

foldable side panels

20 and 21. Container or bag 11 has a tubelike bottom section aligned with and connected to the lower end of peripheral wall 16. Bottom section 25 is formed with front and back

plain panels

27 and 28, and inwardly

foldable side panels

30 and 31. It is preferable to make bag 11 and bottom section 25 of a single piece of suitable flexible material so that

panels

27, 28, 30 and 31 are integrally connected to

panel

17, 18, 20 and 21, respectively. Although not absolutely necessary, it usually is desirable to provide container 10 with a plurality of circumferentially spaced flexible reinforcing strips 35 extending the length of peripheral wall 16 and extending into the bottom section 25, as shown. In this example, a reinforcing strip is provided at each corner of the bag, and another strip is provided centrally of each of the front, back and side panels. Each strip 35 has a loop 37 formed at its upper end adjacent the upper end at 12 of bag 11.

Suitable cover means and fastening means are provided for the bag. In this example, the bag is formed with a tubular cover section 39 which is an extension of the bag itself. This cover section has front and

back panels

40 and 41, and

side panels

42 and 43.

Grommets

46 and 47 are formed in

side panels

42 and 43 near the outer or free edges thereof. Stiffening strips 50 and 51 extend along and are secured to the free edges of front and

back panels

40 and 41. The illustrated container bag has a plurality of resilient straps 53 secured at one end thereof to the back panel 18 of the bag near the back cover panel 41, see FIG. 6, each strap having a hook 54 connected to its opposite end. A grommet 56, see FIG. 5, is provided on front panel 17 for each hook 54.

Back panel 28 of bottom section 25 is produced downwardly beyond the other panels of the bottom sec tion to form a flap 60 which actually constitutes part of the bottom part of the container. This flap has a reinforcing piece 61 secured thereto near its free end, and a slot 62 extends through this reinforcing piece and the adjacent portion of the flap.

Suitable securing is provided for container 10, and in this example the securing means is in the form of a latch 65. This latch consists of a trigger plate 67 swingably connected by a hinge 68 to a base plate 69 which is secured to front panel 17 of the peripheral wall 16. It is preferable to provide a reinforcing piece 70 at the point where base plate 69 is secured to the wall panel. A loop 73 is secured to base plate 69 and projects outwardly therefrom, and is positioned to extend through a slot 74 formed in trigger plate 67 near the outer end of the latter when this plate is swung upwardly and inwardly towards the peripheral wall of the bag. A lanyard loop 77 is connected to and projects outwardly from the free end of trigger plate 67, and a lanyard 78 is secured at one end to this loop and at its opposite end to a locking pin 79.

When container 10 is not in use, it usually is collapsed so that it can be folded or rolled up for storage or shipment. FIGS. 3 and 4 illustrate bag 11 almost in the completely collapsed state. In order to collapse the bag,

side panels

20, 30 and 21, 31 are pressed or folded inwardly and this draws the front and back panels towards each other so that the entire container can be laid flat with flap 60 projecting from one end thereof. Bottom section 25 can now be folded over roughly along the line 83 in FIG. 1 and at 84 in FIG. 3 so that it lies over front panel 17 of the peripheral wall of the bag. At this time, trigger plate 67 is swung upwardly and inwardly to cause loop 73 to project through its slot 74. Flap 60 is moved towards the bag to cause loop 73 to project through slot 74 of this flap. When pin 79 is inserted through a protruding portion of loop 73, the bottom section is latched or secured into its bag-closing position. The container may now be folded or rolled up into a compact bundle for shipment or storage.

When it is desired to fill container 10, the top thereof is supported and held open in any desired manner.

Cover section 39 is held open at this time, and the ore concentrate or other particulate material is directed into bag 11 through the open top thereof. This completely fills out the bag. As the bag fills, the front, back and side panels thereof move outwardly, but since the bottom section 25 of the bag is folded over the lower end thereof and extends part way up the outer surface of peripheral wall 16, the lower portions of each of the

side panels

20 and 21 fold downwardly roughly along the

lines

94 and 95, see FIGS. 1 and 2, which are arranged approximately in a V relative to each other. When the bag is full, the bottom section is flattened as shown in FIG. 7. After

side panels

42 and 43 of cover section 39 are folded inwardly, see FIG. 5, they are secured together in any suitable manner, such as by means of a hook 96 hooked into

grommets

46 and 47. Following this, stiffening strips 50 and 51 are brought together, FIG. 6, and then rolled towards the main portion of the bag, as shown in FIG. 2, at which time the cover section 39 rolls around these strips until the roll is stopped by the material in the bag. Straps 53 are moved over the rolled cover section and hooks 54 are engaged in grommets 56 to retain the cover section in this rolled position. The ore concentrate is now completely enclosed within the container bag.

The filled bag can be lifted in any desired manner. For example, it can be lifted by a plurality of cables 97 having hooks 98 on their lower ends which engage loops 37 at the upper end of the body of bag 11. These can be connected to a common ring 99 which may be placed over the hook of a crane or the like.

When the loaded container is placed on a flat surface 100, as diagrammatically illustrated in FIG. 7, the ore tends to spread the lower portionof the bag outwardly, as shown, so that a flat bottom 101 is created upon which the load rests. The bag is now quite stable and can be left in this position without any support at the top thereof. At the same time, the weight of the material is on the folded-over portion of bottom section 25 so that there is no possibility of any of the material getting out of the bag, and moisture cannot get into it. It will be noted that the free edge of bottom section 25 is positioned well above the supporting surface at this time so that even if the bag is sitting in water, the latter cannot get into the bottom section. The bottom of the bag is sealed by the weight of the material in it.

FIG. 8 diagrammatically illustrates loaded container as it appears when suspended from a crane or the like. When it is desired to unload the container, it is only necessary to withdraw pin 79 from loop 73. This can be done, when the container is suspended, by means of a rope 102 connected to pin 79. When the pin is withdrawn, there is a tendency for flap 60 and bottom section 25 to remain in the closed position. A further pull by means of rope 102 will swing trigger plate 67 outwardly on its hinge 68 to shift flap 60 off loop 73. At this time, the contents of the bag tend to slip down through tubular bottom section 25 and this swings the bottom section and the flap downwardly until the material freely runs out of the bottom of the bag. FIG. 9 shows the bottom section and the flap moved partly to the fully open position, while FIG. 10 shows these in the fully open position and the bag emptied. The bag now can be folded up as described above and shipped back for another load.

The material to be transported may be of a powdery nature, in which case there is danger of pollution of the air and product loss if this container is loaded and unloaded as described above. An alternative form of container 10a, see FIG. 11, is provided for this purpose. The container bag 11 is provided with a cover section in the form of a flexible cover 106 in place of cover section 39, said cover 106 being connected to the peripheral wall 16 of the bag almost completely closing the top of the bag. A flexible or collapsible tubular sleeve 108 is secured to cover 106 and opens into the bag. This sleeve is adapted to fit over a spout 110, which discharges the material to be transported into the bag. The sleeve may be large enough to fit loosely over the spout so as to permit air to discharge from the bag during the filling operation, or it can be clamped to the spout, in which case a flexible vent tube 112 may be provided, and this tube can extend back to the hopper containing the material.

When the container bag is full, sleeve 108 and tube 112 may be rolled up in the same manner as cover section 39 of container 10 and secured in place by straps and hooks similar to straps 53 and hooks 54 or by a suitable flap.

FIG. 12 illustrates a way of supporting a container 10b while it is being loaded through a spout 115. A plurality of cables 116 are hooked to some of the loops 37 and extend upwardly and over pulleys 117 to a common counterbalance 118.

When the container bag is empty, it hangs with its folded-over bottom section 25 spaced a little above a support 120. As material is poured into the bag, the latter first fills out as described above, and then as the weight in the bag increases, the bag moves downwardly until it rests on support 120. This allows the folds of the material of the bottom of the bag to shift into their proper positions before the weight of the material seals the bag bottom. In this way it is not necessary to support the total weight of the load during the loading operation.

It is obvious that container 10 can be supported during loading in the manner illustrated in FIG. 12.

When it is desired to unload the transporting container with a minimum of dust being discharged to the atmosphere, the latch is released while the bag is resting on a support such as illustrated in FIG. 7. Then the bag is raised by a crane through cables 98. As the bag moves upwardly, the bottom section thereof unfolds and allows the material to flow out of the bag on to the support, which may be the bottom of a bin. In all unloading operations there is relative movement between the material and the bag, and in the last-described operation, the bag in effect moves relative to the material, whereas when the container is completely suspended at the movement of discharge, the material moves relative to the bag.

Bag

10, 10a or 10b and the elements integrally connected thereto may be formed of any suitable strong and waterproof material. For example, up to 5 tons of ore concentrate have been successfully carried in a bag made from polyvinyl chloride-coated woven polyester material weighing 26 ozs. per square yard. Two-inch nylonbraided webbing having a breaking point of 6,000lbs. has been found suitable for reinforcing strips 35. Alternatively, these strips can be made of a material that can be welded to the bag material rather than being sewn thereto. Although the bag may have any suitable dimensions, the bag used for up to 5 tons of concentrate was approximately 3 feet on each side and had a height of about 5.5 feet.

We claim:

1. A container for transporting particulate material comprising a flexible tubular bag of substantially rectangular cross section and having a peripheral wall forming a main holding section, a tube-like bottom section of substantially rectangular cross section and aligned with and connected to a lower end of the bag wall, said peripheral wall and said bottom section hav ing opposed side panels that fold inwardly when the bag is collapsed and having opposed plain other panels, said side panels of the bottom section when the bag is collapsed being foldable inwardly relative to the adjacent end of the holding section, said plain panels of the bottom section being foldable inwardly over said infolded side panels and said end of the holding section to close the end of the holding section and one of said plain panels extending upwardly along the outer surface of the peripheral wall, and releasable securing means coacting between the bottom section and the adjacent peripheral wall of the holding section releasably to secure said bottom section and said wall together, said securing means comprising a trigger plate having a slot therein and hingedly secured to a plain panel of the peripheral wall, a loop secured to said wall and positioned to extend through the plate slot when said plate is swung towards the peripheral wall, a slot formed in said upwardly extending plain panel and positioned to fit over the loop when the bottom section is folded into theclosing position with said upwardly extending plain panel overlying the trigger plate, and pin means engageable with the portion of the loop extending through the plate slot and the plain panel slot releasably to prevent the trigger plate and the upwardly extending plain panel from being swung away from the peripheral wall, and when the plate is swung away from the peripheral wall after withdrawal of the pin means said upwardly extending plain panel is moved off the loop to free the bottom section, whereby when there is particulate material in the holding section of the bag, the weight of said material pressing against the foldedover bottom section helps to seal the lower end of the bag and yet when said upwardly extending plain panel is moved off the loop the bottom section straightens out and the particulate wall is instantly discharged when the bag is supported near the top thereof.

2. A container for transporting heavy particulate ma terial, comprising a tube-like bag having a peripheral wall forming a main'holding section, a tube-like bottom section aligned with and connected to a lower end of the bag wall, said bottom section being foldable over and across the adjacent end of the holding section and upwardly along the outer surface of the peripheral wall to close the end of the holding section, said folded-over portion of the bottom section supporting the load of the heavy particulate material in the bag when the bag is suspended from the top thereof and the load pressing against said folded over portion helping to seal the lower end of the bag, securing means in the form of interconnectable and releasable securing members on the bottom section and the adjacent peripheral wall of the holding section respectively, said securing means comprising a slot formed in a portion of the bottom section which extends over the outer surface of the peripheral wall of the bag when the bottom section is folded over into the closing position, a loop secured to the peripheral wall and positioned to extend through said slot when the bottom section is folded over, a trigger plate having a slot therein and hingedly secured to the peripheral wall, said plate being positioned so that said loop extends through the plate slot when the plate is swung towards the peripheral wall, and pin means engageable with the portion of the loop extending through the slots in the bottom portion and the plate releasably to prevent the bottom section and the trigger plate from moving away from the peripheral wall, and when the plate is swung away from the peripheral wall after withdrawal of the pin means said portion of the bottom section being moved off the loop to free the bottom section so that said bottom section straightens out under the load and permits instant discharge of the particulate material during suspension of the bag.

3. A container for transporting heavy particulate material as claimed in claim 2 including a flap secured to and forming part of said one plain panel and extending upwardly along the outer surface of the peripheral wall, said slot of said one planed panel being formed in said flap.

4. A transporting container as claimed in claim 2 including flexible reinforcing strips connected to and extending the length of said peripheral wall and extending into said bottom section.

5. A transporting container as claimed in claim 2 including a tube-like cover section connected to an upper end of the bag wall and foldable inwardly to close the main holding section of the bag.

6. A transporting container as claimed in claim 4 including fastening means for releasably retaining said cover section in the inwardly folded position.

7. A transporting container as claimed in claim 2 including a flexible cover connected to an upper end of the bag wall, and a flexible sleeve secured to said cover and opening into the holding section.

8. A transporting container as claimed in claim 3 including loops connected to upper ends of the reinforcing strips by means of which said bag can be lifted.

Claims

1. A container for transporting particulate material comprising a flexible tubular bag of substantially rectangular cross section and having a peripheral wall forming a main holding section, a tube-like bottom section of substantially rectangular cross section and aligned with and connected to a lower end of the bag wall, said peripheral wall and said bottom section having opposed side panels that fold inwardly when the bag is collapsed and having opposed plain other panels, said side panels of the bottom section when the bag is collapsed being foldable inwardly relative to the adjacent end of the holding section, said plain panels of the bottom section being foldable inwardly over said infolded side panels and said end of the holding section to close the end of the holding section and one of said plain panels extending upwardly along the outer surface of the peripheral wall, and releasable securing means coacting between the bottom section and the adjacent peripheral wall of the holding section releasably to secure said bottom section and said wall together, said securing means comprising a trigger plate having a slot therein and hingedly secured to a plain panel of the peripheral wall, a loop secured to said wall and positioned to extend through the plate slot when said plate is swung towards the peripheral wall, a slot formed in said upwardly extending plAin panel and positioned to fit over the loop when the bottom section is folded into the closing position with said upwardly extending plain panel overlying the trigger plate, and pin means engageable with the portion of the loop extending through the plate slot and the plain panel slot releasably to prevent the trigger plate and the upwardly extending plain panel from being swung away from the peripheral wall, and when the plate is swung away from the peripheral wall after withdrawal of the pin means said upwardly extending plain panel is moved off the loop to free the bottom section, whereby when there is particulate material in the holding section of the bag, the weight of said material pressing against the folded-over bottom section helps to seal the lower end of the bag and yet when said upwardly extending plain panel is moved off the loop the bottom section straightens out and the particulate wall is instantly discharged when the bag is supported near the top thereof.

2. A container for transporting heavy particulate material, comprising a tube-like bag having a peripheral wall forming a main holding section, a tube-like bottom section aligned with and connected to a lower end of the bag wall, said bottom section being foldable over and across the adjacent end of the holding section and upwardly along the outer surface of the peripheral wall to close the end of the holding section, said folded-over portion of the bottom section supporting the load of the heavy particulate material in the bag when the bag is suspended from the top thereof and the load pressing against said folded-over portion helping to seal the lower end of the bag, securing means in the form of interconnectable and releasable securing members on the bottom section and the adjacent peripheral wall of the holding section respectively, said securing means comprising a slot formed in a portion of the bottom section which extends over the outer surface of the peripheral wall of the bag when the bottom section is folded over into the closing position, a loop secured to the peripheral wall and positioned to extend through said slot when the bottom section is folded over, a trigger plate having a slot therein and hingedly secured to the peripheral wall, said plate being positioned so that said loop extends through the plate slot when the plate is swung towards the peripheral wall, and pin means engageable with the portion of the loop extending through the slots in the bottom portion and the plate releasably to prevent the bottom section and the trigger plate from moving away from the peripheral wall, and when the plate is swung away from the peripheral wall after withdrawal of the pin means said portion of the bottom section being moved off the loop to free the bottom section so that said bottom section straightens out under the load and permits instant discharge of the particulate material during suspension of the bag.