Method of manufacturing an FIBC, FIBC

Abstract

A novel method for manufacturing a cubicle flexible intermediate bulk container is disclosed. At least two opposing sidewalls of the cubicle FIBC has a lower portion and an upper portion, both of which are formed of a combination of sheet material cut in rectangular and trapezoidal geometries.

Claims

1. A method of manufacturing a Flexible Intermediate Bulk Container (FIBC), comprising the steps of; a) cutting flexible sheet material in the form of a rectangular envelope for forming a sidewall of the FIBC; b) marking the envelope such that the envelope has an upper portion and a lower portion; c) folding right and left side edges of the upper portion such that the upper portion has a first upper portion in the form of a rectangle having a predetermined height, a second upper portion in the form of an isosceles trapezoid whose upper base is wider than its lower base and whose side edge is inclined with an angle of α1 with respect to the vertical axis, a third upper portion in the form of an isosceles trapezoid whose upper base is wider than its lower base and whose side edge is inclined with an angle of β1 with respect to the vertical axis; d) folding right and left side edges of the lower portion such that lower portion has a first lower portion in the form of a rectangle having a predetermined height, a second lower portion is in the form of an isosceles trapezoid whose lower base is wider than its upper base and whose side edge is inclined with an angle of α2 with respect to the vertical axis, a third lower portion is in the form of an isosceles trapezoid whose lower base is wider than its upper base and whose side edge is inclined with an angle of β2 with respect to the vertical axis; e) tacking the folded right and left side edges of the lower portion and the upper portion; f) stacking three upper portions and three lower portions to form the sidewall of the FIBC, wherein the sidewall has narrowed width in its middle parts and full width in first and last portions along the vertical direction; g) stitching side edges of four sidewalls to each other such that all sidewalls of the FIBC are formed; h) stitching a bottom wall to the lower edges of the four sidewalls; and i) stitching a plurality of handles to the sidewalls of the FIBC.

2. The method of manufacturing an FIBC as set forth in claim 1 wherein the angles made by the side edges of the trapezoids are in the following ranges: 7°≤α1≤15° 9°≤α2≤16° 2°≤β1≤7° 2°≤β2≤7°.

3. The method of manufacturing an FIBC as set forth in claim 1 wherein the maximum amount of offset folded at a junction of third upper portion and the third lower portion is made at a vertical position ranging from 38% to 46% of a total height of the sidewall, measured from the lower edge of the sidewall.

4. A FIBC obtained by the manufacturing method of claim 1.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

(1) The figures whose brief explanations are herewith provided are solely intended for providing a better understanding of the present invention and are as such not intended to define the scope of protection or the context in which said scope is interpreted in the absence of the description.

(2) FIG. 1 shows a 2-dimensional view of the sidewall of an FIBC according to the present invention,

(3) FIG. 2 shows a 2-dimensional view of an envelope used for forming the sidewall of an FIBC according to the present invention,

(4) FIGS. 3a, 3b and 3c show a plurality of sidewalls of an FIBC according to the present invention, side edges of said sidewalls are shown as tacked but unstitched state,

(5) FIGS. 4a-4d show perspective and side views of an FIBC whose two opposing side walls are manufactured according to the present invention,

(6) FIGS. 5a-5d show perspective and side views of an FIBC whose four side walls are manufactured according to the present invention,

(7) FIG. 6 shows a two dimensional view of the sidewall of an FIBC according to the present invention where reference is made to lower, upper and side edges of a sidewall of an FIBC with respect to the vertical axis (y) and horizontal axis (x).

DETAILED DESCRIPTION OF THE INVENTION

(8) The list of reference numerals used in the appended drawings is as follows;

(9) 1 FIBC

(10) 10 Envelope

(11) 11 Sidewall

(12) 12 Side edge

(13) 14 Upper edge

(14) 15 Lower edge

(15) 16 Filling spout

(16) 17 Discharge spout

(17) 18 Handle

(18) The stacking of known FIBCs one above the other is hampered by generally the convergent shape of the FIBC. If FIBCs have to be stacked in confined spaces such as shipping containers, the bulge in the middle and lower part and the constriction in the upper part of the FIBCs leads to stability problems. In order to solve the problems occurring in the prior art, the FIBC according to the present invention does not present the known rectangular shape when in the unfilled state. FIG. 1 and FIG. 2 shows a 2-dimensional view of the sidewall of an FIBC according to the present invention. As clearly seen, the sidewall of an FIBC is made by folding the two side edges of a perfectly rectangular envelope (10) which is shown by dashed lines on the right and left part of FIG. 2. As the FIBC is made of a flexible material, such as a polypropylene fabric, folding the two side edges of the envelope (10) made out of sheet material is easy. Folded portions of the envelope (10) are illustrated in dashed lines.

(19) As clearly seen in FIG. 2, folding the two side edges of the envelope (10) is made uniformly along the vertical dimension of the sidewall (11) of the FIBC. The sidewall (11) of the FIBC according to the present invention is wider in the upper and lower portions of the FIBC as compared to the width in approximately the middle portion. The sidewall is formed of an upper portion UP formed of three portions UP1, UP2 and UP3. While the first upper portion UP1 has a rectangular geometry, the remaining upper portions UP2 and UP3 are in the shape of an isosceles trapezoid. The lower portion LP of the sidewall of the FIBC is formed of three portions LP1, LP2 and LP3. While the first lower portion LP1 has a rectangular geometry, the remaining lower portions LP2 and LP3 are in the shape of an isosceles trapezoid. The six portions forming the sidewall (11) of the FIBC are stacked such that a sidewall has narrowed width in its middle parts and full width in the first and last portions along the vertical direction.

(20) As isosceles trapezoid is a closed geometry having a lower base and an upper base which are parallel to each other and which have different lengths. The two side edges have the same length and are symmetric to each other, implying that they make the same internal corner angles with both the upper base and the lower base.

(21) FIGS. 3a, 3b and 3c show a plurality of sidewalls of an FIBC according to the present invention. The side edges of the sidewalls (11) are shown as in a tacked state. Once the two side edges are folded towards the inside of the sidewall (11), they are tacked in order to preserve the modified geometry of the sidewall until the time the tacked side edge is stitched to the side edge of a neighboring sidewall of the FIBC. The tacked parts of the sidewalls are shown by hatch lines in FIGS. 3a, 3b and 3c.

(22) FIG. 4a to FIG. 4d show perspective and side views of an FIBC whose two opposing side walls are manufactured according to the present invention. This implies that two opposing sidewalls present a rectangular geometry while the remaining two opposing sidewalls have an upper portion UP and a lower portion LP which have varying width in the vertical direction (y) of the FIBC (1) as taught by the present invention. The vertical dimension of the FIBC is the direction starting from the lower edge (15) of a sidewall (11) towards the upper edge (14) of the same sidewall.

(23) FIG. 5a to FIG. 5d show perspective and side views of an FIBC whose four side walls are manufactured according to the present invention. This implies that the all four sidewalls (11) of the FIBC (1) have a lower portion (LP1, LP2, LP3) and an upper portion (UP1, UP2, UP3). The FIBC (1) according to the present invention may have a filling spout (16) and a discharge spout (17) as shown in FIG. 5b.

(24) FIG. 6 shows the markings made on an envelope (10) made of sheet material. Vertical direction (y) of an FIBC is defined as the direction starting from the lower edge (15) of a sidewall (11) towards the upper edge (14). As the lower edge (15) of a sidewall is parallel to the upper edge (14) of the same sidewall, the vertical direction (y) is perpendicular to both of the upper and lower edges (14,15). The horizontal direction of the FIBC is the x-direction as shown in FIG. 6.

(25) The method of manufacturing a sidewall (11) of an FIBC (1) according to the present invention starts with the step of method of manufacturing an FIBC, comprising the steps of cutting flexible sheet material in the form of a rectangular envelope for forming a sidewall of the FIBC. As shown in FIG. 6, the envelope is marked such that the envelope has an upper portion (UP1, UP2, UP3) and a lower portion (LP1, LP2, LP3). The method further comprises the steps of;

(26) Folding the right and left side edges of the upper portion UP such that the upper portion has a first upper portion (UP1) in the form of a rectangle having a predetermined height (a), a second upper portion (UP2) in the form of an isosceles trapezoid whose upper base is wider than its lower base and whose side edge is inclined with an angle of α1 with respect to the vertical axis (y), a third upper portion (UP3) in the form of an isosceles trapezoid whose upper base is wider than its lower base and whose side edge is inclined with an angle of β1 with respect to the vertical axis (y),

(27) Folding the right and left side edges of the lower portion (LP) such that lower portion has a first lower portion (LP1) in the form of a rectangle having a predetermined height (f), a second lower portion (LP2) in the form of an isosceles trapezoid whose lower base is wider than its upper base and whose side edge is inclined with an angle of α2 with respect to the vertical axis (y) a third lower portion (LP3) is in the form of an isosceles trapezoid whose lower base is wider than its upper base and whose side edge is inclined with an angle of β2 with respect to the vertical axis (y), as illustrated in FIG. 6.

(28) Once a sidewall (11) is obtained by the folding steps outlines above, the folded side edges of the lower portion (LP1, LP2, LP3) and the upper portion (UP1, UP2, UP3) are tacked. Thereafter, side edges of four sidewalls are stitched to each other such that all sidewalls of a cubical FIBC are formed.

(29) According to the present invention, at least two opposing sidewalls shall be manufactured as outlined by the folding steps taught above. In such a case, the remaining two sidewalls may be in the form of the known rectangular sidewalls. Should any bulging occurs in the sidewalls having the known rectangular geometry, the FIBC may be rotated 90 degrees to so that it may fit into a limited width of a confined box, such as a shipment container. Alternatively, all four sidewalls may be manufactured as taught by the folding steps above. The remaining method steps include stitching a bottom wall to the bottom edges of the four sidewalls and stitching a plurality of handles to the sidewalls of the FIBC.

(30) Referring now back FIG. 6, the applicant has found that the total height of the upper portion (UP1, UP2, UP3) shall not be same with the total height of the lower portion (LP1, LP2, LP3). The reason is simply the fact that the pressure on the lower portion LP is higher than the pressure in the upper portion UP. Furthermore, the applicant further found out that the angles (α1, β1) made by the side edges of the trapezoids (UP2, UP3) of the upper portion shall not be the same with the angles (α2, β2) made by the side edges of the trapezoids (LP2, LP3) of the lower portion. In order to obtain the best result, which implies most reduced bulging of a sidewall, the concerned angles, as illustrated in FIG. 6, shall be in the range of;

(31) 7°≤α1≤15°

(32) 9°≤α2≤16°

(33) 2°≤β1≤7°

(34) 2°≤β2≤7°

(35) for any FIBC having a total height in between 1 m to 2 m, as most commonly used by the industry.

(36) FIG. 6 further shows the amount of folding the side edges of the upper portion (UP1, UP2, UP3). Said amount corresponds to the offset in the x-direction. For the first upper portion UP1, the offset amount is (g), which is the smallest among the offset amount (h) for the second upper portion (UP2) and the offset amount (i) for the third upper portion (UP3). The maximum amount of folded offset occurs at the joint of third upper portion (UP3) and the third lower portion (LP3), designated as (i) in FIG. 6. This maximum amount of folded offset, designated as (i) in FIG. 6, shall be located in the range of 38% to 46% of the total height of the sidewall (11). Assuming a sidewall having a total height of 1 m in y-direction, the maximum amount of folded offset (i) shall be somewhere in between 38 cm to 46 cm height measured from the lower edge (15) of a sidewall (11).