U.S. patent number 3,854,620 [Application Number 05/294,136] was granted by the patent office on 1974-12-17 for container.
This patent grant is currently assigned to Dana Corporation. Invention is credited to Glen W. Saidla.
United States Patent |
3,854,620 |
Saidla |
December 17, 1974 |
CONTAINER
Abstract
A container structure, as for use in storing or transporting
articles, has a pair of end caps at the axial ends of the
intermediate or hollow body portion thereof. The end caps have
inner and outer skins separated by and bonded to plastic foam
material. The inner and outer skins of the end caps each has an
annular lip portion extending axially inwardly toward the medial
portion of the body, with the lip of the inner skin extending
axially inwardly farther than the lip of the outer skin. The end
caps are placed on a mandrel and an inner body skin is wrapped
around the inner lip of the end caps while the outer body skin is
wrapped about the outer lip of the end caps. Plastic foam material
also separates and is bonded to the inner and outer body skins.
Also, the disclosure relates to the method of producing the
container structure.
Inventors: |
Saidla; Glen W. (Wyomissing
Hill, PA) |
Assignee: |
Dana Corporation (Toledo,
OH)
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Family
ID: |
26837197 |
Appl.
No.: |
05/294,136 |
Filed: |
October 2, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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139427 |
May 3, 1971 |
3802975 |
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Current U.S.
Class: |
220/616; 220/1.5;
220/902; 220/62.22; 220/668 |
Current CPC
Class: |
B29D
22/00 (20130101); B65D 90/029 (20130101); B29D
22/003 (20130101); B65D 88/121 (20130101); B29K
2105/06 (20130101); Y10S 220/902 (20130101) |
Current International
Class: |
B29D
22/00 (20060101); B65D 88/00 (20060101); B65D
90/02 (20060101); B65D 88/12 (20060101); B65d
011/22 () |
Field of
Search: |
;220/1.5,9R,9A,9F,10,12,15,71,73,80,84 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,804,739 |
|
May 1970 |
|
DT |
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1,906,143 |
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Aug 1970 |
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DT |
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Primary Examiner: Price; William I.
Assistant Examiner: Marcus; Stephen
Attorney, Agent or Firm: Shall; Harold D. Pollock; Robert
E.
Parent Case Text
SUMMARY OF THE INVENTION
This application is a division of my pending U.S. application Ser.
No. 139,427, filed May 3, 1971, now U.S. Pat. No. 3,802,975.
Claims
Having described this invention and the several embodiments shown
in the drawings, what is claimed is:
1. A container comprising (a) a hollow body section which is
rectangular when viewed in transverse cross-section, (b) at least
one end cap having inner and outer skins spaced from each other and
an inner and outer longitudinally extending lip portion which forms
a part of said inner and outer skins respectively with said inner
lip extending longitudinally beyond said outer lip, (c) a
transversely extending rectangularly shaped end skin portion
connected to said outer lip portion on said outer skin of said end
cap, (d) a rectangular metallic member including four pieces of
angle iron with one leg thereof bonded to said outer lip portion
and the other leg thereof bonded to said end skin portion and
having corner castings interconnecting said pieces of angle iron,
(e) a transversely extending rectangularly shaped end skin portion
on said inner skin connected to said inner lip portion and forming
an end wall for said container, (f) a second rectangular metallic
member comprised of four interconnected pieces of angle iron, (g)
said second rectangular member engaging the surface of said inner
skin which faces said outer skin at the junction of said inner lip
portion and said end skin portion of said inner skin, (h) a
plurality of interconnecting metallic elements connecting said
rectangular metallic members, (i) an inner body skin overlapping
and bonded to said inner lip portion and extending longitudinally
therefrom, (j) an outer body skin overlapping and bonded to said
outer lip portion and extending longitudinally therefrom in a
spaced and substantially parallel relationship with said inner body
skin, (k) a peripheral groove in said outer lip portion spaced
inwardly from the longitudinally inner end thereof and the
overlapping portion of said outer body skin fits into said
peripheral groove, and (l) a core of structural insulating material
disposed between and bonded to said inner and outer end skins and
body skins.
2. A container comprising, (a) a hollow body section, which when
viewed in cross-section includes endless inner and outer body skins
spaced from each other, (b) a structural core disposed in the space
between and bonded to said body skins, (c) an end cap for said
container having an inner and outer longitudinally extending lip
portion connected to opposed inner and outer end cap skins
respectively and said inner lip portion extends longitudinally
beyond said outer lip portion and said inner and outer body skins
overlap said inner and outer lip portions respectively and are
bonded thereto, (d) a peripheral groove in said outer lip portion
and said outer body skin overlaps said outer lip portion and fits
into said peripheral groove, and (e) a structural core between said
end cap skins and bonded to said structural core of said body
section.
3. A container comprising, (a) a hollow body section, which when
viewed in cross-section includes endless inner and outer body skins
spaced from each other, (b) a structural core disposed in the space
between and bonded to said body skins, (c) an end cap for said
container having inner and outer skins spaced apart and inner and
outer longitudinally extending lip portions with said inner lip
portions extending longitudinally beyond said outer lip portion and
said inner and outer body skins overlapping said inner and outer
lip portions respectively and are bonded thereto, (d) an outer end
skin portion of generally rectangular shape on said outer skin
portion of said end cap, (e) an inner end skin portion of generally
rectangular shape on said inner skin portion of said end cap, (f) a
metallic member interconnecting and bonded to said end cap skin and
outer lip portion of said end cap and being rectangular when viewed
in transverse cross-section, (g) a peripheral groove in said outer
lip portion and said outer body skin overlaps said outer lip
portion and fits into said peripheral groove, and (i) a structural
core between said end cap skins and bonded to said structural core
of said body section.
4. A container according to claim 3 wherein said body section has
four walls, one of said walls being a weight supporting wall and
the pair of walls adjacent thereto being side walls, said container
also including a pair of longitudinally extending elements, one of
said elements being secured to the outer surface of said outer skin
at the junction of said supporting wall and one of said side walls
and the other of said elements being secured to the outer surface
of said outer skin at the junction of said supporting wall and the
other of said side walls, the longitudinal ends of said elements
being secured to said rectangular metallic member of said end
caps.
5. A container according to claim 4 including a second pair of
longitudinally extending elements, one of said elements being
secured to the inner surface of said outer skin opposed to said one
of said first pair of elements, the other of said second pair of
elements being secured to the inner surface of said outer skin
opposed to the other of said first pair of elements, the opposed
longitudinal ends of said second elements being secured to said
rectangular members in said end caps, and means extending through
said outer skin to interconnect said first and second pair of
longitudinally extending elements.
6. A container comprising, (a) a hollow body section, which when
viewed in cross-section has four walls and includes endless inner
and outer body skins spaced from each other, (b) a structural core
disposed in the space between and bonded to said body skins, (c) an
end cap for said container having an inner and outer longitudinally
extending lip portion connected to opposed inner and outer end cap
skins respectively and said inner lip portion extends
longitudinally beyond said outer lip portion and said inner and
outer body skins overlap said inner and outer lip portions and are
bonded thereto, (d) one of said four walls being a weight
supporting wall and two other of said four walls are side walls
connected to said one wall, (e) a plurality of longitudinally
extending beam members disposed between said inner and outer body
skins and bonded thereto and overlapping the inner lip portion of
said end cap and being spaced from each other and embedded in said
structural core of said body section, (f) transversely extending
beam members having the transverse ends thereof abut the inner
surface of the outer body skins of said side walls, (g) a pair of
longitudinally extending right angle elements with one of said
elements engaging the inner surface of said outer skin at the
junction of said one wall and one of said side walls and the other
element engaging the inner surface of said outer skin at the
junction of said one wall and the other said side walls and said
elements also engaging said transverse beam members and the opposed
longitudinal ends of said elements being secured to said end caps,
(h) a peripheral groove in said outer lip portion and said outer
body skin overlaps said outer lip portion and fits into said
peripheral groove, and (i) a structural core between said end cap
skins and bonded to said structural core of said body section.
7. A container according to claim 6 including a second pair of
longitudinally extending elements, one of said elements being
secured to the outer surface of said outer skin at the junction of
said one wall and one of said side walls and the other of said
elements being secured to the outer surface of said outer skin at
the junction of said one wall and the other of said side walls, the
longitudinal ends of said second elements being secured to said end
caps and means extending through said outer skin and
interconnecting said first and second elements.
8. A container according to claim 7 wherein said elements are
pieces of angle iron.
9. A wall unit comprising (a) four interconnected wall members
forming a hollow body section which is rectangular when viewed in
transverse cross-section, (b) each of said walls when viewed in
transverse cross-section including inner and outer body skins
spaced from each other with each of said skins being continuous,
(c) at least one of said walls being a weight supporting wall and
including a plurality of spaced longitudinally extending beam
members disposed between said inner and outer body skins and bonded
thereto, (d) a pair of longitudinally extending elements, one of
said elements being secured to the outer surface of said outer skin
at the junction of said weight supporting wall and one of said
walls interconnected thereto, and the other of said longitudinally
extending elements being secured to the outer surface of said outer
skin at the junction of said weight supporting wall and the other
said walls interconnected thereto, (e) a structural core disposed
in the space between said body skins and between said beam members
and bonded to both said body skins and said beam members.
10. A wall unit comprising (a) four interconnected wall members
forming a hollow body section, which is rectangular when viewed in
transverse cross-section, (b) each of said walls when viewed in
transverse cross-section including inner and outer body skins
spaced from each other with each of said skins being continuous,
(c) at least one of said walls being a weight supporting wall and
two other of said walls being side walls, (d) a plurality of spaced
beam members disposed between said inner and outer body skins and
bonded thereto, (e) a structural core disposed in the space between
said body skins and said beam members, (f) a pair of longitudinally
extending elements, one of said elements being secured to the inner
surface of said outer skin at the junction of said one wall and one
of said side walls and the other of said longitudinally extending
elements being connected to the inner surface of said outer skin at
the junction of said one wall and the other of said side walls, (g)
a second pair of longitudinally extending elements, one of said
second elements being secured to the outer surface of said outer
skin at the junction of said one wall and one of said side walls,
and the other of said second elements being secured to the outer
surface of said outer skin at the junction of said one wall and the
other of said side walls.
Description
This invention is concerned with fabricated container structures
having improved structural characteristics and more particularly to
such a structure with inner and outer skins with insulating
structural material therebetween. It also relates to a container
structure wherein the end caps are securely connected to the medial
hollow body portion of the container.
In the prior art manufacture of container structures having inner
and outer skins separated by insulating material, such as that
shown in U.S. Pat. No. 3,295,279, the manner of securing separately
formed end caps to the body portion of the structure has presented
problems.
In the present invention, by forming the end caps with a pair of
axially extending lips, the inner of which is overlapped and bonded
to the inner skin of the body portion and the outer lip of the end
cap being overlapped and bonded to the outer skin of the body
portion, the end caps are intimately secured to the body
portion.
The present invention also provides the insulating material between
the inner and outer skins of the body portion of the container by
the novel method of first wrapping a mandrel with the inner skin,
placing a foam box about the inner skin, foaming the plastic
material as a core between the inner skin and the mandrel, removing
the foam box, then wrapping the outer skin around the foamed
material to provide a sandwich structure of inner and outer skins
with the foam material therebetween.
It is, therefore, an object of this invention to provide a wall
unit comprising a relatively thin inner and outer skin with foam
insulating material between the skins, which structure is
manufactured by rapid assembly and mass production methods.
It is another object of this invention to provide a container
wherein the wall or body portion is positively secured to end caps
and a manufacturing method for obtaining such structure.
Further and other objects of this invention will become apparent
from the detailed description and the following drawings,
wherein:
FIG. 1 is a perspective view of a container incorporating this
invention;
FIG. 2 is a longitudinal cross-sectional view of the end cap
portions of the container disposed on a mandrel utilized in
manufacturing the same, the end caps being viewed as though the
section was taken along lines 2--2 in FIG. 1;
FIG. 3 is a partial longitudinal sectional view taken similarly to
FIG. 2 with the inner skin of the body portion of the container
being shown in place;
FIG. 4 is a partial longitudinal sectional view taken similarly to
FIG. 3 with the intermediate insulating layer of the body portion
shown applied on the inner skin;
FIG. 5 is a partial longitudinal sectional view taken similarly to
FIG. 4 with the outer skin shown applied over the insulating layer
and outer lips of the end caps;
FIG. 6 is a longitudinal sectional view taken similarly to FIG. 2
of the end caps of a second embodiment of this invention, however,
the section has been taken with the bottom of the container facing
upwardly;
FIG. 7 is a partial transverse cross-sectional view taken along the
lines 7--7 of FIG. 6;
FIG. 8 is a partial longitudinal sectional view taken similarly to
FIG. 6 of the second embodiment of this invention with the inner
skin applied and a longitudinally extending I-Beam being shown in
position;
FIG. 9 is a partial longitudinal sectional view taken similarly to
FIG. 8 of the second embodiment of this invention with the outer
skin applied;
FIG. 10 is a schematic view of the mandrel of FIG. 6 as it appears
in transverse cross-section at a position intermediate its ends
with the inner skin being applied thereto by winding equipment also
shown schematically;
FIG. 11 is a schematic view in transverse cross-section similar to
that shown in FIG. 10 of the mandrel with the inner skin and
I-Beams as shown in FIG. 8, with a foam box in place, and also
showing foam supplying equipment schematically;
FIG. 12 is a schematic view similar to that shown in FIG. 11
showing the relationship of the foam box and the semi-completed
container shown in FIG. 3 for applying the body layer shown in FIG.
4;
FIG. 13 is a partial longitudinal cross-sectional view taken
similarly to FIG. 3 showing a wall of the foam box and its
relationship to the end caps of the mandrel;
FIG. 14 is a schematic view taken similarly to FIG. 10 showing the
outer skin being applied to the first embodiment of this
invention;
FIG. 15 is a plan view of a third embodiment of this invention, as
viewed from the bottom, prior to the outer skin and body layer of
insulating material being applied thereto; and,
FIG. 16 is a transverse cross-sectional view taken along the lines
16--16 in FIG. 15 after the container has been finished.
Referring now to the drawings and more particularly to FIGS. 1-5, a
container is shown generally at 10 and has a closed end 12, an open
end 14, and a medial body portion 16. While the container, as
shown, has a general rectangular cross-section, it is readily
apparent that many other cross-sectional configurations can
incorporate the features of this invention. It is understood that
while a closed end is shown at 12, the container can have both ends
made in the manner of the open end 14. Suitable closure means, such
as doors (not shown), can be mounted in the open end 14 to close
the same while providing for easy access into the container. The
closed end 12 is formed by an end cap 18, while the open end 14 is
formed by an end cap 20.
More particularly, the end cap 18 is generally rectangular in
transverse cross-section and includes four corner castings 22, one
at each outer corner thereof. Joining the corner castings 22, as by
being welded thereto, are four right angle shaped metallic members
24, the corner castings and the angle shaped members forming a
rectangular frame. Spaced radially and longitudinally inwardly of
the right angle members 24 is a rectangular member, shown generally
at 26 in FIG. 2, made from fabricated right angle metallic members
28. Interconnecting and welded to the right angle members 24 and
28, at spaced intervals, are a plurality of metallic struts 30.
The rectangular area between the right angle members 24 is enclosed
by an end skin 32 which can be made from a sheet of resin
impregnated material, preferably fiberglass. The end skin 32 may be
hand laid up in a mold (not shown) with the peripheral portions of
the skin overlapping the adjacent radially extending leg portion
24A of the angle member 24 and with portions of the skin being
wrapped around the struts 30 to interlock the skin and the angle
members 24.
An outer lip portion 34, which is rectangular when viewed in
transverse cross-section, extends longitudinally inwardly from the
longitudinally extending leg 24B of the right angle member 24. The
longitudinally outer edge of the lip portion 34 overlies the inner
surface of the leg 24B and is wrapped around a plurality of
inwardly projecting short lugs 36 that are welded to the inner
surface of the leg 24B at spaced intervals. The lip 34 is made from
a sheet of resin impregnated material, preferably fiberglass, which
may be hand laid up and cured in a suitable mold. The outer lip 34
is shaped to have a peripheral indentation or groove 38 spaced
longitudinally outwardly from the inner end thereof. The right wall
40 of the groove 38 is angled sharply upwardly to a longitudinally
inward shoulder 42 of the outer lip 34, while the left wall of the
groove slopes upwardly at a lesser angle to a shoulder 44 of the
lip; the shoulder 44 being spaced outwardly with respect to the
center of the container 10 to a greater distance than the shoulder
42. Accordingly, the outer skin of the end cap 18 includes the end
skin 32, the angle members 24 and the outer lip 34.
The end cap 18 also has an inner skin 48 which has a rectangularly
shaped end skin portion 50 and an inner lip portion 52 formed
integrally therewith and extending longitudinally inwardly
therefrom. The inner lip portion 52 is rectangular when seen in
transverse cross-section and has an inner end portion 54 that
extends longitudinally inwardly beyond the outer lip portion 34.
The junction of the end skin 50 and the inner lip portion 52 is
generally at right angles and fits into the angled portion of the
rectangular member 26. The inner skin 48 is made from a sheet of
resin impregnated material, preferably fiberglass, which may be
hand laid up and cured in a suitable mold.
The space between the inner and outer skins of the end cap 18 is
filled with a plastic foam insulating core material 55, such as a
closed cell polyurethane foam, more fully explained hereinafter,
with the foam in the lip portion of the end cap as shown in FIG. 2
extending longitudinally inwardly to the inner end of the outer lip
34; the inner portion 54 of the inner lip 52 projecting
longitudinally inwardly beyond the core material. In one manner of
making the end cap 18, the corner castings 22, with the angle
members 24 and 28, are placed in a female mold (not shown) and the
end skin 32 and lip portion 34 hand laid up into this mold. The
inner skin 48 is hand laid up around a male mold (not shown), the
male mold is then placed into the female mold with the inner skin
48 resting upon the angled frame 26, and the insulating material
foamed therebetween.
As seen in FIG. 2, in the manufacturing process the end cap 18 is
slipped over one end of a mandrel 56 which is rectangular in
cross-section and closely fits with the inner lip portion 52 of the
end cap. The specific details of the mandrel 56 do not form a part
of this invention, however, it is desirable that the mandrel is of
a structure which allows it to be collapsed and withdrawn from the
open end of the finished container.
The end cap 20 forming the open end 14 of the container 10 includes
four corner castings 60 and four channel shaped metallic members 62
joined to the corner castings as by welding to form a rectangular
frame. The open side of the channel faces longitudinally inwardly
and the inner surface of the inner and outer legs 64 and 66 of the
channel are provided with a plurality of spaced short lugs 68
welded thereon.
The end cap 20 has an outer lip portion 70 which can be made from a
sheet of resin impregnated material, such as fiberglass, which may
be hand laid up and cured in a suitable mold. The longitudinally
outer edge of the sheet overlies the inner surface of the outer leg
66 and is wrapped around the lug 68. The outer lip 70 is shaped to
have a peripheral indentation or groove 72 therein spaced
longitudinally outwardly from the inner end thereof. The left wall
76 of the groove 72 is angled sharply upwardly to a longitudinally
inward shoulder 78, while the right wall of the groove slopes
upwardly at a lesser angle to an outer shoulder 80; the shoulder 80
being at a greater distance from the center of the container 10
than the shoulder 78. Accordingly, the outer skin of the end cap 20
includes the lip portion 70, the outer leg 66 and the vertical wall
80 of the channel member 62.
The end cap 20 also has an inner lip portion 82 which can be made
from a sheet of resin impregnated material, such as fiberglass,
which may be hand laid up and cured in a suitable mold. The
longitudinally outer edge of the sheet overlies the inner surface
of the inner leg 64 and is wrapped around the lugs 68. The inner
lip 82 is rectangular when seen in transverse cross-section and has
an inner end portion 84 that extends longitudinally inwardly beyond
the outer lip portion 70. Accordingly, the inner skin of the end
cap 20 includes the inner lip portion 82 and the inner leg 64 of
the channel member 62.
The fiberglass portions of the end caps 18 and 20 may be made from
suitable types of fiberglass material such as either woven
fiberglass roving or chopped strand fiberglass mat. A material
which has been found to be satisfactory is referred to as chopped
strand mat, type M700 obtainable from the Owens-Corning Fiber Glass
Corporation, utilized with a polyester resin; a suitable resin
being obtainable from PPG Industries, Inc. and identified as number
50894. It should also be understood that the fiberglass portion of
the end caps 18 and 20 can be formed by the spray up or other
suitable method.
The space between the inner and outer skins of the end cap 20 is
filled with a plastic foam insulating core material 86, such as
closed cell polyurethane foam, more fully explained hereinafter,
with the foam in the lip portion of the end cap extending
longitudinally inwardly to the inner end of the outer lip 70; the
inner portion 84 of the inner lip 82 projecting longitudinally
inwardly beyond the insulating material. As seen in FIG. 2, in the
manufacturing process, the end cap 20 is slipped over the end of
the mandrel 56 oppositely from the end cap 18, with the mandrel
closely fitting within the inner lip portion 82 and inner flange 64
of the end cap 20. It is also understood, that in the manufacturing
process, suitable parting agents are first placed on the surface of
the mandrel before the end caps are inserted thereover to prevent
the various skin layers from adhering thereto in the manufacturing
operation and to provide for easy subsequent removal of the
mandrel.
A pair of supporting wheels 88 and 90 are attached to the end caps
18 and 20 for supporting and rotating the end caps and the mandrel
as necessary during the various production steps. More
particularly, the corner castings 22 and 60 are of hollow generally
cubic form, with a plurality of oblong openings 23 extending
through the walls thereof; one of the openings in each corner
casting facing longitudinally outwardly. The wheels 88 and 90 have
a diameter greater than the diagonal distance of an end cap when
measured through the corner castings 22 for the end cap 18 and when
measured through the castings 60 for the end cap 20. The wheel 88
is positioned coaxially with and adjacent to the end cap 18 with
suitable attaching means such as a shouldered bolt 92 securing the
wheel to each of the corner castings 22, while the wheel 90 is
similarly positioned relative to and secured to the corner casting
60. The periphery of the wheels 88 and 90 are formed with gear
teeth thereon.
Referring briefly to FIG. 10, a pair of laterally spaced floor
mounted pedestals 94 and 96 are disposed below the wheel 90 with
the pedestals rotatably mounting thereon a small toothed wheel 99
and 98, respectively, meshed with and supporting the wheel 90.
Referring to FIG. 2, the pedestal 96 has a motor 100 mounted
thereon, with the motor drivingly connected to the small wheel 98
of this pedestal, whereby the wheel 98 may rotate the mandrel 56
and end caps 18 and 20. A pair of laterally spaced pedestals, one
of which is seen at 101 in FIG., are disposed below the wheel 88,
with each pedestal mounting thereon a small toothed wheel 102
meshed with and supporting the wheel 88. The small wheels 99 and
102 need only be idler wheels performing no driving function unless
suitable modification is made if desired.
Referring now to FIG. 3, an inner body skin 104 is placed about the
mandrel 56 and overlapping the inner portions 54 and 84 of the
inner lip portions 52 and 82 of the end caps 18 and 20
respectively. While the inner body skin may be placed about the
mandrel in any one of several suitable methods, the preferred
method for rapid production purposes is shown schematically in FIG.
10. A supply of fiberglass roving, such as continuous strand
roving, number 891, Type 30, obtainable from the Owens-Corning
Fiber Glass Corporation, is shown at 106. This roving is lead
through a container 108 of suitable resin, such as a polyester
resin number 50894 obtainable from PPG Industries, Inc., so that
the resin thoroughly coats the roving. The roving is then lead to
the mandrel 56 and the mandrel rotated, thereby to wind the roving
about the mandrel 56 forming the inner body skin 104, which extends
over the lip portions 54 and 84. The winding is continued until the
desired thickness is obtained; it is understood that suitable means
are provided for insuring that the winding progresses for the
desired longitudinal extent. Such may be accomplished by providing
a supporting platform 109 which carries the resin container 108 and
a spindle 107 upon which the roving supply 106 is rotatably
mounted. The platform 109 is supported by a plurality of pairs of
wheels, one pair being shown at 111, interconnected by an axle 113;
the wheels 111 moving within a pair of spaced longitudinally
extending tracks 111A. A reversible motor 115 is carried by the
platform 109 and is drivingly connected to the axle by a gear set
115A, and suitable controls (not shown) are provided for energizing
the motor 115 to move the platform longitudinally as desired.
Referring again to FIG. 2, since the outer lip portions 34 and 70
terminate longitudinally outwardly of the portions 54 and 84, they
do not interfere with the application of the inner body skin 104.
At the location where the inner body skin 104 overlaps the lip
portions 54 and 84, there are a pair of spaced shoulders 108 and
110, however, since these are internal from the outer surface of
the container 10, they have no effect on function or
appearance.
Referring now to FIG. 4, a body layer of plastic foam insulating
core material 112 is now placed on the inner body skin and bonded
thereto. The body layer 112 abuts and is bonded to the foam
material 55 and 86 in the end caps 18 and 20 and its external
surface is level and even with the outer surface of the inner
shoulders 42 and 78 of the outer lips 34 and 70.
A preferred method of applying the body layer 112 will be now
described. As seen in FIG. 12, a foam box 114 is positioned about
the semi-finished container of FIG. 3; the mandrel 56, end caps 18
and 20 and body skin 104 are still supported at this time by the
wheels 88 and 90 and pedestals 94, 96 and 100. The foam box 114 is
a hollow structure, open at both ends and rectangular in transverse
cross-section. The bottom wall 116 of the box 114 is carried by a
vertically movable support, such as a piston 117 actuable by the
hydraulic cylinder 118, for moving the bottom wall upwardly to the
position shown in FIG. 12 to the desired space relationship to the
mandrel 56 and downwardly relative thereto after the foaming
operation is completed; the bottom wall having the longitudinally
extending edges thereof bent upwardly to form flanges 119. A pair
of side walls 120 and 122 sealingly rest on the bottom wall 116,
are disposed in a desired space relationship to the mandrel 56 and
abut the inner edges of the flanges 119. A top wall 124 sealingly
rests on top of the side walls 120 and 122 and has the
longitudinally extending edges thereof bent downwardly over the
outside of the side walls 120 and 122.
The relationship of the foam box 114 and the inner shoulders 42 and
78 of the outer lips 34 and 70 of the end caps 18 and 20 is shown
in FIG. 13 with reference to the wall 124; it being understood that
the relationship of the other walls of the foam box is
substantially similar. As clearly seen in this FIG. 13, the wall
124 (as do the walls 116, 120 and 122), at its longitudinal ends
overlaps and abuts the outer surface of the inner shoulders 42 and
78, so that the space between the inner surface of the wall and the
outer surface of the inner body skin 104 is the area into which the
body layer of plastic foam insulating core material 112 is
introduced, with the foam material 55 and 86 in the outer lips 34
and 70 of the end caps 18 and 20, respectively, forming the lateral
ends of the area into which the body layer 112 is placed, such area
being indicated generally at 125 in FIG. 12.
Referring now to FIG. 12, with the foam box 114 in place, a foam
machine 126 is actuated which supplies a properly mixed plastic
foam material through a supply line 128 through the bottom wall 116
of the box 114 to fill the are 125; the amount of plastic
introduced being sufficient to completely fill the are 125 when
foamed and provide a slight overflow through a plurality of vents
in the top of walls 124, one of such vents being shown at 130. A
rapid introduction of plastic foam is desired to insure that all
the area 125 is filled before the plastic begins to cure and entrap
air spaces. It is beneficial to provide that as foam begins to
overflow from a particular vent 130, such vent is closed; this
being repeated successively until overflow has been attained from
all the vents. The plastic foam of the body portion 112 will
securely adhere to the foam material 55 and 56 of the end caps 18
and 20 and will also securely adhere to the body skin 104 and the
inner edges of the lip portions 34 and 70.
In another method of providing the plastic foam insulating layer in
the container 10, the inner and outer skins of the end caps 18 and
20 can be formed and the resin impregnated fiberglass portions
thereof cured without the introduction of the insulating layer of
plastic foam therebetween at such time. After the body skin 104 is
wrapped over the inner end portions 54 and 84, the foam box 114 is
positioned in place and the body layer 112 and end cap material 55
and 86 is introduced in the same operation. In this method,
referring to FIG. 13, the mandrel 56 is provided with a shoulder 57
spaced inwardly from the end of the mandrel adjacent the closed end
cap 18 and a plate 57A is positioned between the shoulder 57 and
the end skin portion 50 of the inner skin 48 of the end cap 18 to
prevent inner movement of the end skin during the foaming of the
plastic. Similarly, a wheel 89, instead of being annular as the
wheel shown in FIG. 2, is provided with a central plate portion 89A
which abuts the outer side of the end skin 32 to prevent outward
movement thereof during foaming of the plastic. No such provision
need be made at the open end cap 20 (even if open end caps are used
at both ends of the container) since the channel member 62 forms
the longitudinal outer end of this end cap.
A suitable type of plastic molding compound for use as the end cap
material 55 and 86 and for the body layer 112 is obtainable from
PPG Industries, Inc. and identified as SELECTROFOAM 65008-6409
System. This is a two component polyurethane foam system which is
properly mixed in the foam machine 126 to start the chemical
foaming action. Additionally, to speed up the foam expansion
process and create a froth foam for more rapid filling of the end
caps and body layer, and subsequent to filling, less expansion
through chemical foaming, a suitable blowing agent such as Freon 12
is added to the two components at the mixing head. Polyurethane
foam has been found to be very satisfactory because of its inherent
structural strength, low thermal conductivity, low density, bonding
ability and its ability to completely fill a cavity into which it
is introduced.
Referring now to FIG. 5, the finished container 10 is shown with an
outer body skin 132 in place. The outer body skin 132 is made from
a suitable material such as resin impregnated fiberglass, reference
being made to the previous discussion of the inner skin 104 for
description of suitable materials, and overlies the body layer of
insulating material 112 and the outer lip portions 34 and 70 of the
end caps 18 and 20. The skin 132 at the grooves 38 and 72 of the
lip portions 34 and 70 is thickened and completely fills the
grooves so that the outer surface of the skin 132 is level with the
outer shoulders 44 and 80 of the end caps 18 and 20. Since the
inner body skin 104 overlaps and is bonded to the inner lip
portions 52 and 82 of the end caps 18 and 20, and the outer body
skin 132 overlaps and is bonded to the outer lip portions 34 and 70
and secured in the grooves 38 and 72, the end caps 18 and 20 are
intimately and securedly attached to the body portion 16 of the
container in a manner heretobefore unknown in the art.
Additionally, the structure of the end caps themselves, with the
inner and outer skins separately and intimately secured to the
rectangular assembly of the corner castings and connecting members,
provide a connnection hereinbefore unknown in the art.
While the outer body skin 132 may be placed about the body layer
112 and lip portions 34 and 70 in any one of several suitable
methods, the preferred method for rapid production purposes is
shown schematically in FIG. 14 after removing the cured
semi-finished container from the foam box 114 and suitably treating
the surface of the polyurethane foam body portion 112 to enhance
its bonding properties, such as by sanding, wiping with a solvent
such as methylene chloride, or chilling the foam box before removal
which provides a friable surface to the foam. The wheel 90 is
driven to rotate thereby rotating the semi-finished container to
wrap fiberglass roving from the supply 106, which has passed
through the resin container 108, around the outer lip portions 34
and 70 and the body layer 112. The motor 115 drives the platform
109 to move longitudinally of the container as required to warp the
outer skin 132, a dwell being provided in the platform's movement
in the area of the grooves 38 and 72 so that the grooves are
completely filled. Tracts 111A, shown in both FIGS. 10 and 14,
guide the movement of the wheels 111 supporting the platform
109.
Referring now to FIGS. 6 - 9, a second embodiment is shown. In FIG.
6, a pair of end caps 18A and 20A are shown which are the same as
end caps 18 and 20 except that the upper transverse wall 138
thereof, as seen in FIGS. 5 and 6, has been modified to provide a
plurality of longitudinally extending transversely spaced slots 140
in each end cap with each slot in end cap 18A being in an aligned
and paired relationship with a slot 140 in the end cap 20A; note
that the lower wall as seen in FIGS. 5 and 6 is not slotted, as is
the case with the two side walls. While the wall 138 is shown as
being the upper wall in these drawings, such is placed in the upper
position pg,16 for production purposes, and after the container 10A
of this embodiment is finished, as seen in FIG. 9, the upper wall
can be the bottom strengthened wall of the container in such cases
when the container carries its load on the bottom floor thereof, or
it can be used as the upper wall when the weight is suspended from
the upper wall.
The slots 140 are provided in the outer lip portions 34A and 70A of
the end caps, and both the outer skin and insulating material are
absent from the slots; the inner lip portions 52 and 82 of the end
caps are not slotted. The slots 140 extend longitudinally inwardly
almost to the outer end of the grooves 38A and 72A; the point of
intersection indicated at 142 is the same distance from the center
of the container as the outer surface of the shoulders 42A and 78A
of the outer lips 34A and 78A. As seen in FIG. 7, the outer side of
the laterally outermost grooves 140 are aligned with the outer
surface of the inner lip portion 52A of the side walls of the end
caps 18A. The same is true of the slots in the end cap 20A.
Referring now to FIG. 8, after the inner body skin 104 has been
wrapped around the mandrel and over the inner lip portions 52 and
82, a longitudinally extending I-beam 144 is placed in each pair of
the aligned slots 140. The beams 144 are conventionally shaped,
having upper and lower flanges 146 and 148 and a web 150. The
length of the I-Beams are such that they reach the longitudinal
outer ends of the slots 140 and the height thereof is such that the
top surface of the upper flange 146 is co-extensive with the outer
surface of the shoulders 42A and 72A. The width of the flanges 146
and 148 fits closely within the width of the slots 140. The medial
bottom portions of the beams 144 rest upon and are bonded to the
portion of the inner skin 104 intermediate the end caps 18A and
20A. Where the inner skin overlaps the inner lip portions 52 and
82, the lower flange 148 of the beams 144 are cut away to
accommodate the same. At the end of the overlap of the inner skin
104, the lower flanges 148 are cut away, but to a lesser extent
than at the overlap.
The end portions of the I-Beams 144 within the slots 140 and
longitudinally outwardly of the shoulders 42A and 78A are each
provided with a groove or indentation 152 which matches the groove
38A or 72A adjacent thereto. The I-Beams can be made of fiberglass
filled polyester resin which have been suitably formed. The
fiberglass and polyester resin for making the beams 144 can be the
same type as that previously utilized to wind the body skins 104
and 132. The beams are preferably bonded to the inner skin 104 and
the inner lip portions 52 and 82 outwardly of the area where they
overlap the body skin by the same type of polyester resin.
After the I-Beams 144 have been positioned as described, the
semi-completed container is placed in a foam box 114A as shown
schematically in FIG. 11, with the I-Beams disposed upwardly. The
bottom and side walls 116, 120 and 122 of the foam box 114A are the
same as the corresponding walls of the foam box 114 in FIG. 12, as
is the piston 117 and cylinder 118. The top wall 124A of the box
114A is provided with a plurality of vents 130A, with some disposed
so as to be open between the location of adjacent I-Beams and
between the outermost I-Beams and the side walls 120 and 122.
The top wall 124A also has a pair of longitudinal extensions (not
shown) which extend beyond the shoulders 42A and 72A and which
overlie and abut the outer ends of the I-Beams 144 and the lip
portions 34A and 70A to at least the point of intersection 142 of
the notches 140 and the outer lips.
A foam machine 126 is actuated which supplies properly mixed
polyurethane foam through a main supply line 154 through the bottom
wall 116 of the box 114A to fill the space between the side and
bottom walls of the box 114A and the container; it is noted that
the polyurethane foam reaches the top wall 124A of the box outside
of the outermost I-Beams 144, but cannot flow across between the
top wall and the container because these outermost I-Beams act as a
dam. A branch supply line 156 extends from the supply line 154 and
carries polyurethane foam to a top manifold supply 158 with a
plurality of branches 160; each branch extending through the top
wall 124A at a location intermediate a pair of adjacent I-Beams 144
to fill the area between the beams.
After the foam has cured, the foam box is removed and the outer
body skin 132, as seen in FIG. 9, is applied to complete the
container 10A. The skin 132 overlaps the end caps 18A and 20A and
at the location of the grooves 152 in the I-Beams the skin lies
within the grooves 152 and the grooves 38A and 72A of the end
caps.
Referring now to FIG. 15, a third embodiment of this invention is
shown at 10C prior to the outer body skin and body layer of
insulating material being applied. The end caps 18C and 20C are
constructed similar to the end caps of FIG. 2 (the minor
differences will be explained hereinafter) and placed on a mandrel.
The inner body skin 104 is then applied, subsequent to which a
plurality of transversely extending I-Beams 170 are spaced along
the container with their bottom flanges 171 (as seen in FIG. 16)
bonded to the body skin 104. The beams 170 extend beyond the inner
skin, preferably to such an extent as to be co-extensive with the
outer surface of the body layer of insulating material 174 which
will be applied, and the top surface of the top flange 175 of the
I-Beams is co-extensive with the top surface of the inner shoulder
176 of the end caps.
The upper side and outer end surface of each I-Beam at both of the
corners 178 thereof are provided with a notch 180, as seen in FIG.
16. Similarly, each of the top corners of the outer lips 34C and
70C of the end caps 18C and 20C, including the location at the
groove portion 38C and 72C therein, are likewise notched. A pair of
longitudinally extending pieces of angle iron 182 and 184 is
provided, with the angle iron 182 being fitted and bonded into the
notches 180 at one end of the I-Beams 170 and the corresponding
notch in the end caps. The angle iron 182 extends to the aligned
corner castings 22C and 60C and is welded thereto. The angle iron
184 is similarly fitted and bonded into the notches 180 at the
opposite end of beams 170 and into the notches in the corresponding
grooves in the end caps 18C and 20C, with the ends thereof welded
to the aligned corner castings 22C and 60C. The portion of the
angle irons 182 and 184 at the grooves 38C and 72C are deformed so
that the outer surfaces thereof are co-extensive with the surface
of the grooves.
The semi-finished container as shown in FIG. 15 is then placed in a
foam box 114 as shown in FIG. 12, the top wall 124 of the box
touching the top surfaces of the beams 170 and angle irons 182 and
184, and the side walls 120 and 122 of the box touching the lateral
ends of the beams and lateral sides of the angle irons.
Polyurethane foam is then injected into the box 114 through the
line 128 and completely fills the space between the box and the
semi-finished container, including the space between adjacent
I-Beams. After curing the polyurethane foam and removing the box
114, an outer skin 190 is placed around the body layer of
insulating material, the I-Beams 170 and the angle irons 182 and
184 in the same manner as shown in FIG. 14.
Another pair of longitudinally extending angle irons 192 are then
placed on the corners of the container 10C, under which corners are
the angle irons 182 and 184. These angle irons 192 are
longitudinally straight and fit to the corners of the outer skin
190 and the ends thereof are welded to the corner castings 22C and
60C. A plurality of aligned holes are then drilled through the
angle irons 182, 184 and the angle iron 192 adjacent thereto. These
holes also pass through the outer skin 190 and a rivet 194 is
placed in each set of aligned holes to securely fasten the angle
irons to each other.
* * * * *