U.S. patent application number 13/012980 was filed with the patent office on 2012-07-26 for collapsible drum with reinforced ends.
Invention is credited to James A. Colony, John H. Lapoint, III, John Stuart.
Application Number | 20120187116 13/012980 |
Document ID | / |
Family ID | 46543409 |
Filed Date | 2012-07-26 |
United States Patent
Application |
20120187116 |
Kind Code |
A1 |
Lapoint, III; John H. ; et
al. |
July 26, 2012 |
COLLAPSIBLE DRUM WITH REINFORCED ENDS
Abstract
The present invention is directed to a collapsible drum for
transporting materials. The present invention solves problems
associated with reusing and efficiently transporting shipping
containers designed for retaining bulk materials, including
hazardous substances, and insuring reliable structural integrity
with every use. The collapsible drum of the present invention is
adapted for integration with standard handling equipment, and has a
permanently secured, collapsible drum floor and fluted sidewalls
that enable an operator to collapse and roll the empty drum into a
compact tube. The collapsible drum provides one or more removable,
ribbed disc-shaped inserts for reinforcing the drum floor and/or
drum lid.
Inventors: |
Lapoint, III; John H.;
(Kennebunk, ME) ; Stuart; John; (Belgrade, ME)
; Colony; James A.; (Harvard, MA) |
Family ID: |
46543409 |
Appl. No.: |
13/012980 |
Filed: |
January 25, 2011 |
Current U.S.
Class: |
220/4.09 ;
220/1.6; 220/7 |
Current CPC
Class: |
B65D 37/00 20130101;
B65D 88/1625 20130101 |
Class at
Publication: |
220/4.09 ;
220/1.6; 220/7 |
International
Class: |
B65D 8/14 20060101
B65D008/14; B65D 90/08 20060101 B65D090/08; B65D 88/08 20060101
B65D088/08 |
Claims
1) A collapsible drum for handling materials, the collapsible drum
comprising: a) a plurality of vertical ribs for supporting the wall
of the drum in an erected state, the plurality of vertical ribs
being connected or disconnected along the circumferential plane of
the drum; b) a flexible skin covering the external surfaces of the
vertical ribs; c) a flexible drum floor permanently secured to the
flexible skin covering the external surfaces of the ribs; d) one or
more lifting features secured to a pair of diametrically opposed
vertical ribs thereby facilitating lifting of a loaded or partially
loaded drum by drum handling equipment; and e) one or more
removable ribbed disc-shaped reinforcement inserts layered upon the
inside surface of the flexible drum floor such that the planar
surfaces of the one or more removable disc-shaped reinforcement
inserts are parallel to the drum floor and such that the entire
circumferential edge of each of the one or more ribbed disc-shaped
reinforcement insert is adjacent the inner surface of the wall of
the drum in an erected state.
2) The collapsible drum of claim 1 wherein the pair of
diametrically opposed vertical ribs having one or more lifting
features thereon have higher shear strength than the remainder of
the plurality of vertical ribs.
3) The collapsible drum of claim 1 wherein at least a subset of the
vertical ribs is connected along the circumferential plane of the
drum and this subset of ribs is produced from rigid fiberboard
scored to form the ribs.
4) The collapsible drum of claim 3 wherein the rigid fiberboard is
scored evenly from both sides and to the same depth on both sides
so that the compressed portion of the fiberboard is centered
between the inner and outer surfaces of vertical ribs.
5) The collapsible drum of claim 1 wherein at least a subset of the
vertical ribs is connected along the circumferential plane of the
drum and this subset of ribs is produced by extrusion.
6) The collapsible drum of claim 1, wherein at least a subset of
the vertical ribs is connected along the circumferential plane of
the drum and this subset of ribs is produced by injection molding
onto the flexible skin.
7) The collapsible drum of claim 1 wherein at least a subset of the
vertical ribs is connected along the circumferential plane of the
drum and this subset of ribs is produced by pressing a deformable
rigid material.
8) The collapsible drum of claim 1, further comprising an inner
lamination layer disposed on the internal surfaces of the plurality
of vertical ribs and overlapping the top edges and bottom edges of
the plurality of vertical ribs to adhere to the external surfaces
of the plurality of vertical ribs.
9) The collapsible drum of claim 8 wherein the flexible skin
covering the external surfaces of the vertical ribs overlaps the
top edges of the plurality of vertical ribs to securely adhere to
the inner lamination layer and extends beyond the bottom edges of
the plurality of vertical panels to create a free-hanging bottom
margin.
10) The collapsible drum of claim 9 wherein the free-hanging bottom
margin of the flexible skin covering the external surfaces of the
vertical ribs folds inward along the radius of the drum to lie
parallel to the flexible drum floor during mating.
11) The collapsible drum of claim 10 wherein the flexible drum
floor is permanently attached to the bottom margin by stitching the
two layers together in a continuous circumferential loop in the
plane of the flexible drum floor.
12) The collapsible drum of claim 10 wherein the flexible drum
floor is permanently attached to the bottom margin by welding the
two layers together in a continuous circumferential loop in the
plane of the flexible drum floor.
13) The collapsible drum of claim 10 wherein the flexible drum
floor further comprises at least two parallel layers and wherein
the bottom margin of the flexible skin covering the external
surfaces of the vertical ribs is sandwiched between the two
parallel layers prior to mating.
14) The collapsible drum of claim 1 wherein the flexible drum floor
is made of the same material as the flexible skin covering the
external surfaces of the vertical ribs.
15) The collapsible container of claim 1 wherein the flexible drum
floor is manufactured from a non-rigid woven material with a low
modulus of elasticity.
16) The collapsible drum of claim 1 wherein the flexible drum floor
is manufactured from a material chosen from the group consisting of
woven polyurethane, reinforced polyethylene, woven fiberglass, and
polymeric material.
17) The collapsible drum of claim 1 wherein the inner lamination
layer is manufactured from a material chosen from the group
consisting of woven polyurethane, reinforced polyethylene, woven
fiberglass, and polymeric material.
18) The collapsible drum of claim 1 wherein the flexible skin
covering the external surfaces of the vertical ribs is manufactured
from a material chosen from the group consisting of woven
polyurethane, reinforced polyethylene, woven fiberglass and
polymeric material.
19) The collapsible drum of claim 1 wherein the a plurality of
vertical ribs are made from a material chosen from the group
consisting of fiberboard, cardboard, high density polyethylene,
wood, metal, composite and polymeric material
20) The collapsible drum of claim 1, further comprising a retaining
element secured to the inner surface of the flexible drum floor for
retaining a disposable liner disposed within the containment
cavity.
21) The collapsible drum of claim 20 wherein the retaining element
is Velcro.RTM. and a mating Velcro.RTM. portion is attached to an
outer surface of the disposable liner.
22) The collapsible drum of claim 1 wherein the one or more ribbed
disc-shaped reinforcement inserts further comprise an outer skin
layer.
23) The collapsible drum of claim 22 wherein the outer skin layer
is adhered to the outer surfaces of the one or more disc-shaped
reinforcement inserts.
24) The collapsible drum of claim 22 wherein the outer skin layer
is shrink wrapped around the one or more disc-shaped reinforcement
inserts.
25) The collapsible drum of claim 22 wherein the one or more
disc-shaped reinforcement inserts are injection molded onto the
outer skin layer.
26) The collapsible drum of claim 22 wherein the outer skin layer
is manufactured from a material chosen from the group consisting of
woven polyurethane, reinforced polyethylene, woven fiberglass, and
polymeric material.
27) The collapsible drum of claim 1 wherein at least a subset of
the ribs of the one or more disc-shaped reinforcement inserts are
parallel and connected, and wherein this subset of ribs is produced
from rigid fiberboard scored to form the ribs.
28) The collapsible drum of claim 27 wherein the rigid fiberboard
is scored evenly from both sides and to the same depth on both
sides so that the compressed portion of the fiberboard is centered
between the top and bottom surfaces of the ribs.
29) The collapsible drum of claim 1 wherein at least a subset of
the ribs of the one or more disc-shaped reinforcement inserts are
parallel and connected, and wherein this subset of ribs is produced
by extrusion.
30) The collapsible drum of claim 1 wherein at least a subset of
the ribs of the one or more disc-shaped reinforcement inserts are
parallel and connected, and wherein this subset of ribs is produced
by pressing a deformable rigid material.
31) The collapsible drum of claim 1, further comprising two ribbed
disc-shaped reinforcement inserts wherein the ribs on each insert
are parallel.
32) The collapsible drum of claim 31 wherein the two ribbed
disc-shaped inserts are inserted into the drum such that the
parallel ribs of one ribbed disc-shaped insert are aligned at an
angle between 0 and 180 degrees relative to the parallel ribs of
the other ribbed disc-shaped reinforcement insert.
33) The collapsible drum of claim 31 wherein the two ribbed
disc-shaped inserts are inserted into the drum such that the
parallel ribs of one ribbed disc-shaped insert are aligned at an
angle at or between 30 and 150 degrees relative to the parallel
ribs of the other ribbed disc-shaped reinforcement insert.
34) The collapsible drum of claim 31 wherein the two ribbed
disc-shaped inserts are inserted into the drum such that the
parallel ribs of one ribbed disc-shaped insert are aligned at an
angle of 90 degrees relative to the parallel ribs of the other
ribbed disc-shaped reinforcement insert.
35) The collapsible drum of claim 1 further comprising an
integrated lid attached to the collapsible drum and manufactured
from a flexible material.
36) The collapsible drum of claim 35 wherein the flexible material
is a material chosen from the group consisting of woven
polyurethane, reinforced polyethylene, woven fiberglass, and
polymeric material.
37) The collapsible drum of claim 35 further comprising a buckle
closure extending between the integrated lid and the external
surface of the collapsible drum.
38) The collapsible drum of claim 35 further comprising Velcro.RTM.
extending between the integrated lid and the external surface of
the collapsible drum.
39) The collapsible drum of claim 35 further comprising one or more
snaps extending between the integrated lid and the external surface
of the collapsible drum.
40) The collapsible drum of claim 35 further comprising one or more
ties extending between the integrated lid and the external surface
of the collapsible drum.
41) The collapsible drum of claim 35 further comprising a ribbed
disc-shaped insert disposed on and parallel to an inside surface of
the integrated lid.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a collapsible
shipping container for transporting bulk materials and more
specifically to a reusable collapsible drum with a permanently
attached, collapsible bottom panel and at least one selectively
removable panel insert for reinforcing the collapsible bottom panel
in its expanded state.
[0003] 2. Discussion of Background information
[0004] Plastic and steel drum-style shipping containers commonly
retain bulk materials for transportation. These drum containers
often transport hazardous liquid and powder materials over long
distances without any loss or seepage. Securely retaining hazardous
materials in a transport drum is a highly desirable goal, but
standard drums present a number of drawbacks that result in
inefficiencies, lost profits, injuries and negative environmental
impact.
[0005] First, standard drums are cumbersome to maneuver. Operators
managing these drums typically employ specialized handling
equipment designed for engaging these heavy drums and evacuating
contents. Once emptied, these standard drums, such as the
commonplace 55 gallon steel drum, remain heavy and cumbersome to
handle and load onto and off of pallets and shipment trucks. An
operator manually moving empty drums and loading them onto a
flatbed for shipping to a reconditioning center for example, must
move one drum at a time onto a pallet and/or into a truck bed.
These heavy 50-60 pound standard 55 gallon drums lack ergonomic
handholds and require an operator to execute many repetitive,
physically awkward motions to load a fully emptied shipment of
drums back onto a truck or shipment pallet. This repetitive
movement lacks efficiency and raises the potential for injury every
time an operator manually lifts or rolls each
ergonomically-challenged drum.
[0006] Second, standard shipping drums made of steel, plastic, and
aluminum, for example, occupy a significant amount of space during
transport, even when the drums are empty. A standard 53 foot
flatbed trailer truck can transport only 208 of the standard 55
gallon steel drums. A single standard pallet will hold only about 4
drums. This increases the number of trucks required to ship a large
number of drums and thereby increases fuel consumption and harmful
emissions associated with the carbon footprint of the shipping
vessels.
[0007] In addition to causing increased carbon emissions, increased
risk of injury and decreased efficiency related to maneuverability,
standard drums induce frequent replacement costs because the number
of reuses of each drum is limited. Reconditioning a used steel
drum, for example, typically requires rinsing and sandblasting the
inner surfaces so that all contents are completely removed. These
procedures wear the drum walls down and decrease wall thickness,
thereby decreasing structural integrity. UN shipping standards
require certain minimum wall thicknesses and drum compression
strengths for viability. This means that each drum will last
through only a few rounds of reconditioning before failing to
surpass minimum UN requirements. Standard metal and plastic drums
also are susceptible to structural compromise. One dent in a
sidewall will create a zone of weakness, lessening the axial
compression strength and potentially leading to catastrophic
collapse of the drum. Standard steel and plastic drums, therefore,
lack resiliency and catastrophically may fail UN compression
strength tests after suffering a single indentation.
[0008] Some shipping container designs address issues with regard
to reuse and compaction during empty transport. These bags and
collapsible boxes typically are only semi-rigid at best, tend to
bow outward when filled, and are difficult to lift and stack when
filled. Their bottoms typically attach to their sidewalls via
standing seams that can weaken and separate under the forces
applied by container contents. Furthermore, these designs typically
fail to integrate with existing drum handling equipment.
[0009] A need therefore exists for a reliable, environmentally
friendly, highly reusable, fully collapsible rigid drum for use in
transporting solid and liquid material governed by the dangerous
goods code of the UN regulations. A need exists for such a drum
that is designed for integration with existing transportation and
handling equipment, wherein the drum is capable of withstanding
substantial compression forces without diminishment and capable of
collapsing into a compact roll for ergonomic maneuvering and
efficient transport when empty. Furthermore a need exists for such
a drum having an optional, removable stiffening element for
reinforcing a non-rigid, flexible bottom layer of the drum so as to
prevent puncture and subsequent leakage of liquid and powered
products contained within the drum, wherein the stiffening
mechanism, upon removal, collapses with the drum for efficient
portage.
SUMMARY OF THE INVENTION
[0010] The present invention solves the problems associated with
reusing and efficiently transporting shipping containers designed
for retaining bulk materials, including hazardous substances, and
insuring reliable structural integrity with every use. The
collapsible drum of the present invention is adapted for
integration with standard handling equipment. The collapsible drum
has a permanently secured, collapsible drum floor and fluted
sidewalls that enable an operator to collapse and roll the empty
drum into a compact tube.
[0011] One embodiment of the collapsible drum of the present
invention comprises a plurality of vertical ribs for supporting the
wall of the drum in an erected state, the plurality of vertical
ribs being connected or disconnected along the circumferential
plane of the drum. The embodiment further comprises a flexible skin
covering the external surfaces of the vertical ribs and a flexible
drum floor permanently secured to the flexible skin covering the
external surfaces of the ribs. One or more lifting features secure
to a pair of diametrically opposed vertical ribs, thereby
facilitating lifting of a loaded or partially loaded drum by
standard drum handling equipment.
[0012] In one embodiment, the plurality of vertical ribs are
manufactured from scored fiberboard, and the flexible floor is
permanently attached to the flexible skin by fusing the two
components together in the plane of the flexible drum floor thereby
creating a flat, overlapped, non-standing seam. For example, the
seam may be stitched, welded, glued and/or bonded in any permanent,
continuous loop disposed on, in and/or through the flexible drum
floor.
[0013] In one embodiment, the collapsible drum further comprises
one or more removable ribbed disc-shaped reinforcement inserts
sized and shaped for placement along the bottom of the drum. In one
embodiment, the ribbed disc-shaped inserts are formed in the same
manner and from the same materials as the collapsible drum such
that the ribbed disc-shaped inserts, upon removal, flexibly curl
around the collapsed, rolled drum for efficient, compact
portage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] One will better understand these and other features,
aspects, and advantages of the present invention following a review
of the description, appended claims, and accompanying drawings:
[0015] FIG. 1A depicts a side view of one embodiment of the
collapsible drum of the present invention.
[0016] FIG. 1B depicts a cross sectional top view of one embodiment
of the collapsible drum of the present invention.
[0017] FIG. 1C depicts a side view of one embodiment of the
collapsible drum of the present invention with a cover
attached.
[0018] FIG. 1D depicts an enlarged partial view of the embodiment
of FIG. 1C.
[0019] FIG. 1E depicts a perspective bottom view of one embodiment
of the collapsible drum of the present invention.
[0020] FIG. 2A depicts a cut away cross sectional end view of one
embodiment of the collapsible drum of the present invention.
[0021] FIG. 2B depicts an enlarged partial view of the embodiment
of FIG. 2A.
[0022] FIG. 3A depicts a cross sectional, cut away side view of the
top end of one embodiment of the collapsible drum of the present
invention.
[0023] FIG. 3B depicts a cross sectional, cut away side view of the
bottom end of one embodiment of the collapsible drum of the present
invention prior to attachment of a bottom panel.
[0024] FIG. 4 depicts a perspective end view of one embodiment of
the collapsible drum of the present invention in a semi-collapsed
state.
[0025] FIG. 5 depicts the embodiment of FIG. 4 in a further
collapsed state.
[0026] FIG. 6 depicts a perspective end view of one embodiment of
the collapsible drum of the present invention in a fully-collapsed
state.
[0027] FIG. 7A depicts a front view of one embodiment of a
removable ribbed disc-shaped insert of the collapsible drum.
[0028] FIG. 7B depicts a perspective view of one embodiment of the
removable ribbed disc-shaped insert of FIG. 7A.
[0029] FIG. 7C depicts a side view of one embodiment of the
removable ribbed disc-shaped insert of FIG. 7A.
[0030] FIG. 7D is a blown out, enlarged view of a portion of FIG.
7C.
[0031] FIG. 8A depicts a front perspective exploded view of one
embodiment of two removable ribbed disc-shaped inserts poised for
insertion into the collapsible drum.
[0032] FIG. 8B depicts a side view of FIG. 8A.
DETAILED DESCRIPTION
[0033] The present invention solves the problems associated with
standard drum-style shipping containers.
[0034] FIGS. 1A through 1E depict one embodiment of the collapsible
drum 100 of the present invention. The drum 100 comprises a
plurality of vertical ribs 105 and a permanently attached, flexible
bottom panel 107. The plurality of vertical ribs 105 are rigid
members that support the wall, or body 110, of the drum 100 in an
erected state. Each of the plurality of vertical ribs 105 extends
the entire length of the body 110 and preferably has a continuous
cross sectional profile throughout its length. This uniform cross
sectional profile insures that no weak point exists that would
cause a vertical rib 105 to buckle at that localized weak point
under the application of forces associated with retaining contents
during shipment and handling the drum 100 during stacking, filling
and evacuation processes.
[0035] As FIGS. 2A and 2B depict, the plurality of vertical ribs
105 may be connected along the circumferential plane 115 of the
drum 100. In other embodiments (not shown), the plurality of
vertical ribs 105 may be disconnected along the circumferential
plane 115 of the drum 100. For example, in a disconnected
embodiment, individual loose ribs may be disposed in pockets formed
in a unifying tubular sleeve. In such a loose rib embodiment, the
pockets and ribs therein would be spaced apart by the semi-rigid
sleeve material so that an operator could collapse and roll the
drum into a compressed tube, as indicated in the stages of collapse
depicted in FIGS. 4 to 6. In yet another disconnected rib
embodiment (not shown), individual ribs may be adhered or
mechanically bonded to a flexible tubular sleeve such that the
individual ribs are spaced apart sufficiently to enable compaction
as shown in FIGS. 4 to 6. For example, the ribs may be formed by
injection molding flowable plastic into flexible tubular sleeves of
woven polypropylene or injected in rib form onto woven
polypropylene or any other durable, flexible material capable of
withstanding the temperature and pressures associated with an
injection mold, such as but not limited to woven polyurethane,
reinforced polyethylene, woven fiberglass, and other polymeric
materials. In such an embodiment, the injected plastic will seep
through the scrim of the woven fabric, bonding to the threads
thereof for secure attachment. Alternate embodiments may comprise a
combination of one or more subsets of connected ribs 105 and one or
more subsets of disconnected ribs 105.
[0036] In all embodiments, the plurality of vertical ribs 105 are
preferably evenly spaced with vertical score lines 120, or gaps,
therebetween that enable the body 110 to curve into a cylindrical
shape. The number and size of vertical ribs 105 varies along with
drum size so that all embodiments of the drum 100 take a
cylindrical drum shape. As FIGS. 2A and 2B depict, in one
embodiment, the plurality of ribs 105 are connected and formed by
scoring a single piece of material from both sides to create a
symmetrically necked in area 122 at the vertical score line 120.
Although not required, this symmetry assists with compressing and
rolling the collapsible drum 100 with little resistance. The
symmetrically necked in area 122 requires less physical exertion to
compress the drum 100 into itself as depicted in FIG. 4 and roll
compactly as depicted in FIGS. 5 and 6. If the necked in area 122
were asymmetric so that the material therein were placed more
toward the interior or exterior surface of the body 110, resistance
forces would increase at those locations thereby impeding bending
the body 110 into a rolled shaped. The symmetrical placement of the
necked in area 122 allows the plurality of ribs 105 on the inside
505 of rolled drum 100 to compress toward one another during
collapse and compaction. The symmetrical placement of the necked in
area 122 simultaneously allows the plurality of ribs 105 on the
outside 510 of the rolled drum 100 to expand and fan outward. The
rolling process thereby produces a compact tube such as that
depicted in FIG. 6.
[0037] In addition to compressing fiberboard at selective locations
to form the plurality of vertical ribs 105, other methods of rib
formation exist. In addition to fiberboard, materials of
manufacture may include but are not limited to cardboard, high
density polyethylene, wood, metal, rigid and flexible composites,
fluted plastics, and honeycomb composite. For example, the body 110
of the drum 100 maybe formed of fluted plastic that may be molded,
heat formed or extruded to form the plurality of ribs 105. The body
110 may be manufactured from a stamped flexible sheet metal such as
aluminum or steel alloy. Any number of methods exist for forming
the plurality of ribs 105, but all materials and methods of
manufacture produce a body 110 capable of resisting high
compression strength while enabling collapse during non-use.
[0038] Preferably, the material chosen for the plurality of ribs
105 is lightweight and resistant to both longitudinal and radial
compression and expansion forces. Fiberboard, for example, is
significantly lighter than steel and exhibits high compression
strength in an axial direction. A stack load test conducted on an
embodiment the drum 100 of present invention resulted in
withstanding 7000 pounds of force without any indication of radial
expansion or buckling. The tested embodiment was manufactured from
platen pressed fiberboard comprising one and one half inch wide,
interconnected ribs 105 wrapped in woven polypropylene and lined
inside with four (4) mil woven polyethylene. This trial comprised
more strenuous test conditions than those required by UN shipping
regulations which require dropping each of six equally sized drums
only once for each test. A single 22'' diameter, 34'' high drum of
the fiberboard embodiment of the present invention, dropped sixes
times repeatedly from 1.8 meters, continued exhibiting the 7000 lbf
compression load strength results. A standard steel drum of similar
dimensions typically withstands only 1200 pounds of force under the
less strict UN testing requirements.
[0039] Returning to the embodiment of pressed fiberboard, as the
cross sectional views of FIGS. 2A and 2B depict, the compressed
material located in the neck in area 122 at the vertical score line
120 and connecting adjacent ribs 105 is centered between the inner
and outer surfaces of the plurality of ribs 105. The neck in area
122 at the vertical score line 120 comprises material compressed to
a thickness .tau. that is least half the overall cross sectional
thickness T of each of the plurality of ribs 105 and more
preferably at least a third of the overall thickness T of each of
the plurality of ribs 105. In some embodiments, the neck in area
122 may be compressed so as to be completely planar and sheet-like
in thickness .tau.. Using a driven platen or rotary press and a
compressible material, such as fiberboard, to form the plurality of
ribs 105 enables accurate and efficient production of a drum body
110 having highly compressed material at the neck in area 122 along
each of the vertical score lines 120.
[0040] The out press ridges impact the fiberboard and
simultaneously produce the vertical score lines 120 and the
plurality of ribs 105 therebetween. The press ridges therefore may
be sized so that the vertical score lines 120 have a desired width
.omega.. Wider score lines 120 (i.e. wider gaps between the
plurality of ribs 105) may be preferable for enabling compression
and compaction of a large drum 100 and/or a body 110 having wide
ribs 105. The platen press ridges also may be spaced apart at
particular intervals to produce ribs 105 of desired width W. The
plurality of ribs 105 may be equally sized or may comprise ribs 105
of two or more varying widths W, W'.
[0041] As with selecting the width w of the vertical score lines
120, selecting the spacing between the platen ridges and thereby
determining the width W of each of the plurality ribs 105 may
depend on the overall dimensions of the collapsible drum 100. For
example, a ratio of rib width W to drum diameter D may be between
11:1 and 36:1 and more preferably may be between 17:1 and 25:1. A
ratio of 22:1 enables easy compaction and tight rolling of a drum
having standard drum dimensions of approximately 22 inches in
diameter and 34 inches in height while producing compression
strength results described in the above trial. In such an
embodiment, trials indicated that a compressible drum 100 with
these standard dimensions rolled up into itself more compactly and
with less exertion when each of the plurality of ribs 105 was one
inch wide instead of two inches wide.
[0042] Returning now to FIGS. 2A and 2B, whether the plurality of
ribs 105 are partially or wholly connected and/or disconnected,
embodiments of the collapsible drum 100 further comprise a flexible
skin 125. FIGS. 2A and 2B depict one embodiment wherein the
plurality of ribs 105 are connected and encapsulated by a flexible
skin 125. The flexible skin 125 protects the plurality of ribs 105
from damage from the elements and damage associated with shipping
and handling. Additionally, the flexible skin 125 assists the body
110 with resisting radial forces and preventing bulging during use,
shipping and handling. The flexible skin 125 may be a material such
as, but not limited to, woven polyurethane, reinforced
polyethylene, woven fiberglass, and other polymeric materials.
Preferably the material comprising the flexible skin has a low
modulus of elasticity and therefore contributes to the high bulk
modulus of the collapsible drum 100 of the present invention. The
fibers of the flexible skin 125 preferably exhibit high shear
strength so as to withstand radial and axial compression forces
both under load and under compression while the flexible skin 125
remains supple enough to avoid fiber degradation and shear strength
degradation after repeated compaction and rolling of the drum. For
example, a flexible skin 125 comprising woven polypropylene
counteracts radial expansion forces and produces the above
described trial results in the described fiberboard embodiment of
the collapsible drum 100 of the present invention.
[0043] The flexible skin 125 may be permanently disposed on the
body 110 of the drum 100 using a method such as but not limited to
gluing, epoxying, welding, injection molding, and shrink wrapping.
One embodiment of a method of manufacturing the drum 100 comprises
applying a flexible skin 125 to fiberboard prior to press formation
of the plurality of ribs 105 and vertical score lines 120. This
insures that the flexible skin contours the ribs 105 and vertical
score lines 120 and thereby further assists with withstanding
radial expansion forces acting on the body 110 during periods of
use and enabling efficient collapse and rolling of the drum 100
during periods of non use.
[0044] In one embodiment depicted in the cut away cross sectional
views of FIGS. 3A and 3B, the drum 100 further comprises an inner
lamination layer 130 applied to the interior surfaces of the
plurality of ribs 105. In the embodiment shown, the inner
lamination layer 130 overlaps the end of the plurality of ribs 105
and adheres to the outer surface of the body 110. The inner
lamination layer permanently affixes to the body 110 through means
such as but not limited to gluing, epoxying, welding, injection
molding, and shrink wrapping. Furthermore, the inner lamination
layer 130 may be comprised of a material such as, but not limited
to, woven polyurethane, reinforced polyethylene, woven fiberglass,
and other polymeric materials. In one embodiment, the inner
lamination layer 130 is made of polyethylene and/or polyethylene
film and thereby provides a clean surface against which an optional
disposable inner receptacle, i.e. a liner, may slide during
installation and removal.
[0045] As FIGS. 3A and 3B depict, embodiments of manufacturing the
collapsible drum 100 may comprise applying the inner lamination
layer 130 prior to applying the flexible skin 125. In the
embodiment of FIGS. 3A and 3B, the drum 100 comprises a flexible
skin 125 applied to the outside of the plurality of ribs 105
comprising the body 110 and disposed on the folded over portion of
the inner lamination layer 130 so that the flexible skin overlaps
the inner lamination layer 130 on the inside surface of the
plurality of ribs 105 comprising the body 110. This overlapped
configuration produces a secure bond between the flexible skin 125
and inner lamination layer 130 and thoroughly contributes the
protecting of the ends of the plurality of ribs 105 from
environmental and materials damage. The combination of overlapped
flexible skin 125 and inner lamination layer 130 further
contributes to the high bulk modulus of the drum 100.
[0046] As FIG. 3B depicts, one embodiment of a method of
manufacturing the collapsible drum 100 of the present invention
comprises permanently attaching the flexible drum floor 107 to the
flexible skin 125. The flexible drum floor 107 of the present
invention affixes to the body of the drum 110 at an overlapping
horizontal seam between the flexible skin 125 and the flexible drum
floor 107. Like the flexible skin, the drum floor 107 is made from
a flexible but strong material. Because the drum floor 107 is
flexible, an operator may collapse and roll the drum 100 without
having to remove the drum floor 107. The drum floor 107 material
remains supple and compressible while retaining a low modulus of
elasticity. For example, the flexible floor 107 may be a material
such as, but not limited to, woven polyurethane, reinforced
polyethylene, woven fiberglass, and other polymeric materials.
Preferably the material comprising the flexible skin has a low
modulus of elasticity and therefore contributes to the high bulk
modulus of the collapsible drum 100 of the present invention. The
fibers of the flexible floor 107 preferably exhibit high shear
strength so as to withstand radial and axial compression forces
both under load and under compression while the flexible floor 107
remains supple enough to avoid fiber degradation and shear strength
degradation after repeated compaction and rolling of the drum. For
example, a flexible floor 107 comprising woven polypropylene
counteracts radial expansion forces and produces the above
described trial results in the described fiberboard embodiment of
the collapsible drum 100 of the present invention.
[0047] As the embodiment in FIG. 1E depicts, the flexible drum
floor 107 is permanently secured to the body 110 in a manner that
eliminates the need for a standing seam. Standard drums and bulk
bags typically comprise a floor attached to the sidewalls at a
standing seam. Methods of manufacturing such existing drums are far
more simplistic when the floor attaches at an easily manipulated
standing seam. In such drums, the bottom panel often separates from
the sidewall(s) at the point of attachment when drum contents
induce radial and axial expansion forces. In contrast, the
collapsible drum 100 of the present invention solves this problem
associated with standing seams and provides a highly secure method
of attachment that enables repeated reuse of the drum 100 without
concern of catastrophic failure. As FIG. 3B depicts, the flexible
skin 125 applied to the outside surface of the body 110 extends
beyond the lower ends of the plurality of ribs 105 to form a
free-hanging bottom margin 135. The free-hanging bottom margin 135
then folds inward along the radius of the drum 100 (i.e. at an
angle of 90 degrees from the body) and in the direction of arrow
140 so that the free hanging bottom margin 135 lies parallel to the
plane of the flexible drum floor 107. The flexible drum floor 107
is then disposed on the free hanging bottom margin 135 so that the
flexible drum floor 107 and circumferential free-hanging bottom
margin 135 overlap. Accordingly, the flexible drum floor 107 is
permanently attached to the bottom margin 135 through a permanent
bonding means applied in the plane of the drum floor 107.
[0048] In one embodiment depicted in FIG. 1E, the two layers are
stitched together in a continuous circumferential loop 109 in the
plane of the flexible drum floor 107. In other embodiments, the
drum floor 107 may be permanently attached to the bottom margin 135
by any number of affixation methods including by not limited to
stitching, welding, heat fusing, stapling, and epoxy bonding.
Regardless of the method of attachment, in all embodiments, the two
layers are affixed in a continuous circumferential loop in the
plane of the flexible drum floor 107 so that the drum floor 107
stays securely and permanently affixed to the body 110. Because the
drum floor and bottom margin 135 are bonded in the plane of the
drum floor 107, rather than at a vertical standing seam around the
periphery of the drum 100, no separation risk exists when the drum
100 is in use. Furthermore, in some embodiments, the drum floor 107
may comprise two layers such that the bottom margin 135 is
sandwiched between the two layers of the drum floor 107 prior to
bonding the drum floor 107 to the bottom margin 135. This
configuration strengthens the bond between the bottom margin 135
and the drum floor 107 and further protects the bottom margin 135
from fraying and potentially detaching from the drum floor 107.
[0049] Additionally, a retaining feature (not shown) may be
disposed on the inner surface of the drum floor 107 for retaining a
disposable liner (not shown) within the drum 100. For example, in
one embodiment the retaining feature may be a Velcro.RTM. system,
with a sizeable Velcro.RTM. panel secured to the inside surface of
the drum floor 107 and a mating Velcro.RTM. portion secured to the
liner. Securing at least one Velcro.RTM. panel on at least a third
of the inner surface of the drum floor 107 enables retention of the
disposable liner during contents evacuation. As one of skill in the
art will recognize, other retention systems are capable of
producing the same result such as but not limited to snaps,
zippers, hook and latch, tie downs, and static charge. Such liners
enable transport of hazardous and/or liquid materials without
degrading the components of the collapsible drum and thereby
increase the potential number of reuses of a drum.
[0050] Because the collapsible drum 100 of the present invention is
designed for industrial use, further reinforcement of the drum
floor 107 is desirable during transport of liquid or powdered
materials that could seep out if the drum floor 107 were ruptured
or punctured. Because the drum floor 107 is typically made from a
collapsible fabric as described above, punctures are conceivable
during industrial handling. Reinforcing the drum floor 107 with one
or more stiff, removable ribbed disc-shaped inserts 600 eliminates
the risk of puncturing the drum floor 107 and/or the disposable
liner and adds rigidity to the erected drum 100.
[0051] As shown in FIGS. 7A through 8B, one embodiment of the
disc-shaped insert comprises a plurality of parallel ribs 605. The
disc-shaped insert 600 may be manufactured in the same variety of
ways and from the same materials described in reference to the body
110 of the collapsible drum 100. For example, in one embodiment,
the disc-shaped insert 600 may be manufactured from pressed
fiberboard laminated with one or more woven fiber materials, such
as but not limited to, woven polyurethane, reinforced polyethylene,
woven fiberglass, and other polymeric materials. This low cost,
efficient manufacturing process is described above with regard to
the formation of the vertical ribs 105 of the collapsible drum 100.
As with the vertical ribs 105 of the collapsible drum 100, the
parallel ribs 605 of one embodiment of the disc-shaped insert 600
may be formed by scoring fiberboard from both the top and bottom
planar surfaces of the insert 600.
[0052] Additionally, the laminated outer layer may be a comprised
of one or more sections applied to one or both surfaces of the
insert 600. For example, in one embodiment, a first layer of woven
polyurethane is applied to the top surface of the insert and folded
over and adhered onto the bottom surface. A second layer of woven
polyurethane is applied to the bottom surface and folded over and
adhered to the top surface of the insert 600, atop the first layer
of woven polyurethane. Other embodiments may include, for example,
heat welding a top layer and bottom layer together along the
circumferential edge of the insert 600 or overlapping and adhering
the two layers along the circumferential edge. In all embodiments,
preferably the laminated out layer comprises no raised seam along
the circumferential edge, thereby aiding in the ease of insertion
and removal of the insert 600 into and out of the collapsible drum
100.
[0053] Turning now to the completed construction of the insert 600,
as the side view of FIG. 7C and blown out view 7D depict, the
material of the insert 600 located in the neck in area 622 at the
disc rib score line 620 and connecting adjacent ribs 605 is
centered between the top and bottom surfaces of the plurality of
parallel ribs 605. The neck in area 622 at the disc rib score line
620 comprises material having a thickness t' that is at least half
the overall cross sectional thickness T' of each of the plurality
of parallel ribs 605 and more preferably at least a third of the
overall thickness T' of each of the plurality of parallel ribs 605.
In some embodiments, the neck in area 622 may be completely planar
and sheet-like in thickness t'.
[0054] In one embodiment, using a driven platen or rotary press and
a compressible material, such as fiberboard, to form the plurality
of parallel ribs 605 enables accurate and efficient production of a
ribbed disc-shaped insert 600 having highly compressed material at
the neck in area 622 along each disc rib score line 620. The out
press ridges impact the fiberboard and simultaneously produce the
disc rib score lines 620 and the plurality of parallel ribs 605
therebetween. The press ridges therefore may be sized so that the
disc rib score lines 620 have a desired width w'. Wider score lines
620 (i.e. wider gaps between the plurality of parallel ribs 605)
may be preferable for enabling compression and compaction along
with a collapsible large drum 100 and/or a body 110 having wide
vertical ribs 105. The platen press ridges also may be spaced apart
at particular intervals to produce parallel ribs 605 of desired
width W'. In one embodiment, W'' is smaller than width W associated
with the drum body 110, and the ribbed disc-shaped insert 600
therefore comprises a plurality of parallel ribs 605 that are
narrower than the plurality of vertical ribs 105 of the body 110
(i.e. more parallel ribs 605 per inch on the disc-shaped insert 600
than vertical ribs 105 per inch on the drum body 110). This is
advantageous at least for providing more flexibility in curling a
removed insert 600 around and along the exterior of the rolled drum
100 in its collapsed and compacted state.
[0055] The one or more ribbed disc-shaped inserts 600 therefore are
designed for insertion into the drum during use and for collapsing
with the drum during rolling and compaction. As indicated in FIGS.
8A and 8A, in one embodiment, the one or more ribbed disc-shaped
inserts 600 are sized so that the diameter of each insert 600 is
slightly shorter than the diameter D of the drum 100. The one or
more ribbed disc-shaped inserts 600 therefore, in one embodiment,
contact the inner surface of the drum body 110, enabling the one or
more disc-shaped inserts 600 to self center during insertion.
Because a disc-shaped insert 600 overlies the inside surface of the
drum floor 107, in one embodiment, the non-permanent attachment
means, such as Velcro.RTM., for retaining a disposable liner may be
located along the inner surface of the body 110 in one or more
locations. Furthermore, in one embodiment the one or more
disc-shaped inserts may further comprise non-permanent attachment
means, such as Velcro.RTM. for secure attachment to the inside
surface of the drum floor 107. In an embodiment having at least two
disc shaped inserts, the bottom insert 600 further may comprise
secure but non-permanent attachment means, such as Velcro.RTM., on
a top surface for mating with a corresponding attachment means on
the bottom surface of the top insert 600.
[0056] The plurality of disc ribs 605 of the one or more inserts
600 therefore align parallel with the diameter of the drum 100, and
therefore stiffen the plane of the flexible drum floor 107. The
insert 600 forms a barrier between external elements, such as
pallets, forklifts and other industrial handling equipment, and the
contents of the drum 100. Additionally, the plurality of disc ribs
605 add compression strength along the longitudinal length of the
ribs 605 and thereby assist with expanding and holding the erected
drum 100 in a full drum shape when first unrolled and opened.
Introducing more than one insert 600 further augments all of these
advantages. For example, as indicated in FIGS. 8A and 8B, adding
two inserts with their disc ribs 605 aligned at a non-parallel
angle relative to each other stiffens the flexible floor 107 and
the body 110 so that the drum 100 holds its cylindrical shape and
so that contents therein are protected from external forces. These
external forces could be, for example, industrial handling
equipment that could improperly or roughly engage the drum 100 and
puncture the drum floor 107 and any liners within the drum, thereby
allowing the contents to evacuate undesirably.
[0057] Furthermore, aligning the two inserts 600 so that the axes
of their ribs are at a non-parallel angle relative to one another
assists the drum 100 in holding its cylindrical shape, particularly
immediately following expansion of the drum from a collapsed state.
During the expansion process the drum 100 may present kinks
imparted during collapse and compaction, and the disc-shaped
inserts 600 impart stiffness to the drum body 110 and assist with
opening the cylindrical drum 100 to a fully cylindrical cross
sectional shape.
[0058] In one embodiment, the top rim of the drum 100 further
comprises markings for aligning the axes of the ribs of two disc
shaped inserts 600 so that the disc ribs 605 of one insert 600 form
an angle relative to the disc ribs 605 of the other insert. In one
embodiment, that angle is greater than 0 degrees and less than 180
degrees. Preferably, in one embodiment, the axes of the ribs 605 of
one disc-shaped insert 600 are at an angle at or between 30 and 150
degrees relative to the axes of the ribs 605 of the second
disc-shaped insert 600. In one embodiment, the axes of the ribs 605
of one disc-shaped insert 600 are at an angle of 90 degrees
relative to the axes of the ribs 605 of the second disc-shaped
insert 600, and the rim of the drum 100 is marked accordingly for
aligning the axis of the central rib 605 of each of the two disc
shaped inserts 600. For example, the rim of the drum 100 may be
marked with two diametrically opposed red dots for aligning the
ends of a central rib 605 of a first disc shaped insert 600 and two
diametrically opposed yellow dots for aligning a central rib 605 of
a second disc shaped insert, where a vector between the two red
dots is positioned at a 90 degree angle to a vector between the two
yellow dots. Aligning the two disc shaped inserts 600 so that axes
of their respective ribs form an angle of 90 degrees increases
resistance of the drum wall to radial compression forces especially
applied at or near the drum floor, such as, for example, forces
applied by a misaligned forklift
[0059] Additionally, in one embodiment, a disc shaped insert 600 is
inserted into the lid 160 of the drum and held in place via
frictional forces and/or non-permanent attachment means such as a
two-part Velcro.RTM. system. Adding an insert to the lid 160,
especially a flexible lid 160 made of a woven material such as
woven polypropylene, assists with protecting that flexible member
and provides an additional barrier against puncture by external
elements.
[0060] Furthermore, in some embodiments, the at least one
disc-shaped insert 600 inserted into the drum 100 and any
additional disc-shaped inserts 600 inserted into the drum 100
and/or lid 160, further comprise means for easily grasping and
removing the one or more inserts 600. For example, the one or more
disc-shaped inserts 600 may comprise one or more loops of material
applied to an accessible surface for grasping and pulling the one
or more inserts free of the drum 100 and/or lid 160. The one or
more loops may be made of the same material as the outer lamination
layer and may be applied by techniques such as, but not limited to
stitching, welding, gluing, epoxying, heat welding, stapling and
riveting. In this embodiment, removing an insert 600 from the drum
100, for example, simply requires grasping the loop with one or
more fingers and pulling upward until the insert is free of the
drum 100. Following removal of the insert 600 and compaction of the
drum 100, the insert 600 folds around the compacted drum 100 and
may be secured thereto with a non-permanent attachment means such
as, for example a lace, tie, Velcro.RTM. strap, ratchet strap, etc.
In another embodiment, the insert 600 is left in the drum 100, but
pulled upward so that the insert 600 lies along and contours to the
inner surface of the body 110. The raised disc-shaped insert 600
then is compacted with the drum 100 during the compaction process
discussed hererin with regard to FIGS. 4 through 6. In any
embodiment, storing the one or more inserts 600 adjacent to and
contoured with the collapsed drum 100 saves space and assists with
porting the elements in a tidy, unified package.
[0061] Turning now to the exterior of the drum 100, the present
invention is designed for full integration with existing handling
equipment designed for maneuvering standard, non collapsible
shipping drums. Most notably, the collapsible drum 100 of the
present invention comprises one or more lifting features 145
secured to a pair of diametrically opposed vertical ribs 105. The
lifting features 145 enable handling equipment to securely grasp
the drum 100 during lifting and evacuation processes without the
drum sliding free of the handling equipment. The lifting features
145 thereby facilitate lifting a loaded or partially loaded drum
100 with drum handling equipment. In some embodiments, lifting
features 145 may be disposed on more than two of the plurality of
ribs 105 so as to avoid limiting the directionality of the handling
equipment when engaging the drum 100. Selecting the number and
placement of lifting features 145 depends in part on the volume of
the lifting features 145 and how tightly the drum 100 needs to
collapse and roll for efficient handling and shipment during
periods of non-use.
[0062] In one embodiment depicted in FIG. 2B, the lifting features
145 are rectangular shaped blocks mechanically fastened to the
outside of the drum 100 by a mechanical fastening means 150. The
lifting features 145 may be manufactured from a light weight, solid
material such as but not limited to wood, plastic, metal and epoxy
impregnated fiberglass. The mechanical fastening means 150 are any
known fastening devices such as but not limited to rivets, screws,
nails, glue, welds, and clamps. In the embodiment of FIGS. 2A and
2B, the mechanical fastening means 150 secure the lifting features
145 to a clamping plate 155 wound within the flexible skin 145 and
spaced apart from the plurality of ribs 105. In this embodiment,
the mechanical fastening means 150 pierce only the clamping plate
155 without potentially compromising the structural integrity of
the rib 105 therebeneath.
[0063] In other embodiments, the mechanical fasteners 155 attach
directly to a rib 105 by first puncturing the flexible skin 125. In
these embodiments, the rib 105 to which a mechanical fastener
attaches has a higher shear strength than the remainder of the
plurality of vertical ribs 105 so that attaching the lifting
features 145 does not decrease compression strength and bulk
modulus of the overall drum 100. In some embodiments, these ribs
105 to which mechanical fasteners 155 apply are wider and/or
thicker than the remainder of the plurality of ribs 105. In some
embodiments, the ribs 105 to which mechanical fasteners 155 apply
may be formed integrally with the remainder of the plurality of
ribs 105 or they may be added later as independent panels of the
same or different material of manufacture. In the case of
independent ribs 105 being added for support of lifting features
145, those independent ribs 105 may be joined to the remainder of
the plurality of ribs 105 by a fastening mechanism such as but not
limited to tape, screws, adhesive, pegs, rivets, and nails.
Alternatively, the flexible skin 125 and/or inner lamination layer
130 may hold independent ribs 105 in alignment with adjacent ribs
105.
[0064] In addition to lifting features 145, embodiments of the drum
100 of the present invention also comprise an integrated fabric lid
160. The lid 160 may be made of any flexible, durable material
capable of collapsing with the drum 100 during storage and
providing a barrier between drum contents and the external
environment. The flexible material may be, but is not limited to,
woven polyurethane, reinforced polyethylene, woven fiberglass, or
polymeric material. The lid may be fully detachable or partially
attached in a permanently or semi-permanently manner so as to
insure lid retention and ready availability. In one embodiment
depicted in FIGS. 1A, 1C and 1D, the lid 160 is semi-permanently
attached through a buckle closure 165 extending between the lid and
the outside of the drum 100. Other means of attachment may include
but are not limited to Velcro.RTM., snaps, zippers, and tie downs.
Additionally, in some embodiments, the portion of the lid 160
extending over the outside surface of the drum 100 further may
comprise an elastic tension element integrated therein for securely
attaching the lid 160 to the drum 100. In further embodiments, the
lid 160 may be solid or may comprise a solid feature for forming a
hermetic seal around the drum 100 and/or the liner therein.
[0065] The spaced rib configuration of the present invention
enables an operator to collapse the drum into a sea-shell shape as
indicated in FIG. 4, and roll the drum 100 into a compact tube as
indicated in the stages of rolling depicted in FIGS. 5 and 6. Some
embodiments of the drum of the present invention may include a
latch system 500, such as a two-piece Velcro.RTM. hook and loop
stay, for maintaining the drum 100 in a collapsed and compactly
rolled state. Compacting a standard sized collapsible drum 100
(i.e. 22 inch diameter, 34 inches high) enables an operator to lift
and maneuver the drum 100 without any exertion and without
requiring any specialized handling equipment. Furthermore, a pallet
typically holds only four(4) similarly sized fifty to fifty-five
(50-55) gallon shipping drums, which limits a standard 53 foot
flatbed trailer to transporting only about 208 empty conventional
drums. In comparison, a 53 foot flatbed trailer can transport
approximately eighteen hundred and seventy-two (1872) collapsible
drums 100 of the present invention in their rolled state that
enables the placement of thirty-six(36) units per shipment skid.
This reduces diesel usage and thereby lessens the carbon footprint
associated with the reuse market and shipment of empty drums.
Compaction of the collapsible drums 100 of the present invention
also decreases the required labor associated unloading pallets
and/or boxes of typical standard 50-55 gallon drums.
[0066] It is noted that the foregoing examples have been provided
merely for the purpose of explanation and are in no way to be
construed as limiting of the present invention. While the present
invention has been described with reference to an exemplary
embodiment, it is understood that the words, which have been used
herein, are words of description and illustration, rather than
words of limitation. Changes may be made, within the purview of the
appended claims, as presently stated and as amended, without
departing from the scope and spirit of the present invention in its
aspects. Although the present invention has been described herein
with reference to particular means, materials and embodiments, the
present invention is not intended to be limited to the particulars
disclosed herein; rather, the present invention extends to all
functionally equivalent structures, methods and uses, such as are
within the scope of the appended claims.
* * * * *