U.S. patent application number 10/875818 was filed with the patent office on 2005-12-29 for s-beam garment hanger.
Invention is credited to Fleming, Patrick J..
Application Number | 20050284898 10/875818 |
Document ID | / |
Family ID | 35504515 |
Filed Date | 2005-12-29 |
United States Patent
Application |
20050284898 |
Kind Code |
A1 |
Fleming, Patrick J. |
December 29, 2005 |
S-beam garment hanger
Abstract
This injection molded plastic garment hanger has a body part
formed as a horizontal beam having a generally S-shape cross
section, a hook at the top and optional spring clamps, hooks and
projections on the beam for engaging, holding and supporting
garments.
Inventors: |
Fleming, Patrick J.;
(Cuyahoga Falls, OH) |
Correspondence
Address: |
Kenneth P. George, Esq.
Amster, Rothstein & Ebenstein
90 Park Avenue
New York
NY
10016
US
|
Family ID: |
35504515 |
Appl. No.: |
10/875818 |
Filed: |
June 24, 2004 |
Current U.S.
Class: |
223/85 |
Current CPC
Class: |
A47G 25/488 20130101;
A47G 25/28 20130101; A47G 25/50 20130101 |
Class at
Publication: |
223/085 |
International
Class: |
A41D 027/22 |
Claims
1. An injection molded plastic garment hanger, comprising: a. a
hook having a top part, a stem extending downward from said top
part and a bottom part, and b. a body part formed as a generally
horizontally extending beam having a central part and arms
extending oppositely from said central part and terminating in
opposite ends, said bottom part of said hook being joined to said
central part of said beam, said beam's central part and arms
comprising a web having upper and lower portions and extending
lengthwise of said beam and extending downward from said hook, said
web in cross-section defining a generally S-shape comprising upper
and lower portions thereof, said web's upper portion having a top
part which extends forwardly as a top front flange of said beam
terminating in a font edge, and said web's lower portion having a
bottom part which extends rearwardly as a bottom rear flange of
said beam terminating in a rear edge.
2. A garment hanger according to claim 1 wherein said upper and
lower portions of said S-shape define a set of continuous reverse
curves.
3. A garment hanger according to claim 1 wherein said web further
comprises a top rear flange extending rearwardly from said top
portion of said web along the length thereof, and a bottom front
flange extending frontwardly from said bottom portion of said web
along the length thereof.
4. A garment hanger according to claim 3 wherein said top rear
flange and said top front flange extend generally oppositely from
each other, and said bottom front flange and said bottom rear
flange extend generally oppositely from each other.
5. A garment hanger according to claim 3 wherein said web's upper
portion forms a top foot with said top front and top rear flanges
being top toe and heel elements of said top foot, and said lower
portion forms a bottom foot with said bottom front and rear flanges
being bottom toe and heel elements of said bottom foot.
6. A garment hanger according to claim 5 wherein said top toe and
heel elements extend generally in a top plane and said bottom heel
and toe elements extend generally in a bottom plane generally
parallel to said top plane.
7. A garment hanger according to claim 3 wherein said top front and
top rear flanges extend generally horizontally in a common top
plane, and said bottom front and bottom rear flanges extend
generally horizontally in a common bottom plane.
8. A garment hanger according to claim 1 wherein said web has a
generally uniform thickness.
9. A garment hanger according to claim 4 wherein said web defines a
central vertical plane extending lengthwise therethrough, and said
front top and bottom flanges and said rear top and bottom flanges
have front edges and rear edges respectively which extend forward
and rearward respectively of said central vertical plane by
generally equal distances.
10. A garment hanger according to claim 9 wherein said upper and
lower curves of said S-shape extend forward and rearward of said
central vertical plane generally by the same distance as said front
and rear flanges extend.
11. A hanger according to claim 9 wherein said S-shape in cross
section defines an area forward of said central vertical plane of
said web that is substantially the same as the cross-sectional area
rearward of said central vertical plane.
12. A hanger according to claim 1 wherein said garment hanger is a
one piece injection molded product.
13. A hanger according to claim 1 wherein said S shape cross
section has height to breadth ratio of about 2:1.
14. An injection molded plastic garment hanger, comprising: a. a
hook having a top part, a stem extending downwardly from said top
part and a bottom part, and b. a body part formed as a beam
extending transversely of said hook, said beam having a central
part and arms extending oppositely from said central part and
terminating in opposite ends, said bottom part of said hook being
joined to said central part of said beam, said beam's central part
and arms comprising a web having upper and lower portions extending
lengthwise of said beam and extending downward from said hook, said
web in cross-section defining a generally Z-shape comprising a
stem, with upper and lower portions of said web forming
respectively a top front flange extending forwardly and terminating
in a front edge, and a bottom rear flange extending rearwardly and
terminating in a rear edge.
15. A garment hanger according to claim 14 wherein said web in
cross-section comprises a set of upper and lower Z-shapes, where
each Z-shape has upper and lower generally horizontal feet, and
where the lower foot of the upper Z-shape comprises the upper foot
of the lower Z-shape, this common foot being an intermediate flange
between said top front and bottom rear flanges.
16. A garment hanger according to claim 15 wherein said top front
flange, bottom rear flange and intermediate flange have
substantially the same thickness and depth.
17. A hanger according to claim 14 wherein said garment hanger is a
one piece injection molded product.
18. A hanger according to claim 14 wherein said upper and lower Z
shapes have essentially the same size and shape.
19. A hanger according to claim 14 wherein said web's cross section
has height to breadth ratio of about 2:1.
20. A hanger according to claim 14 wherein said web's cross section
has height to breadth ratio in the range of about 1.7 to 2.4.
21. An injection molded plastic garment hanger comprising: a. a
hook having a top and bottom parts, and b. a body part formed as a
transversely extending beam having a central part and shoulder
parts extending outward from said central part and terminating in
opposite ends, said bottom part of said hook being joined to said
central part of said beam, said shoulder parts situated at an
elevation different from said central part, said beam's central
part and shoulder parts comprising a web extending lengthwise of
said beam and extending downward from said hook, said web in
cross-section defining a generally S-shape comprising upper and
lower portions thereof, said web's upper portion having a top part
which extends forwardly as a top front flange of said beam
terminating in a front edge, and said web's lower portion having a
bottom part which extends rearwardly as a bottom rear flange of
said beam terminating in a rear edge.
22. A hanger according to claim 21 wherein said shoulder parts
curve outward and downward from said central part.
23. A hanger according to claim 21 wherein shoulder parts are at an
elevation above said central part.
Description
FIELD OF THE INVENTION
[0001] This invention is in the field of injection molded plastic
garment hangers for transporting and displaying garments on racks,
and particularly garment hangers of the type where the body part of
the hanger below the rack-engaging hook is a generally straight
horizontal bar having a plurality of spring clamps, hooks and/or
projections for engaging, holding and supporting garments.
BACKGROUND OF THE INVENTION
[0002] Common molded plastic garment hangers of the type whose body
parts are thin straight beams, often bend and sometimes twist and
buckle when loaded. Since these hangers are made, used and
discarded by the millions, economy of manufacture is important, and
accordingly, these hangers are frequently designed to have a thin
I-beam cross-section which requires a relatively small amount of
plastic for a moderately strong hanger.
[0003] The problems of twisting and buckling are common because of
the nature of loading of the hangers, where garment straps or other
garment elements are attached at the ends of the beam, thus
producing cantilever loads and bending, twisting and buckling
stresses. I-beam design, while common, is limited in its usefulness
because the size dimensions of garment hangers are restricted, and
the amount of plastic that can be economically used is also
restricted. One example of a prior art molded garment hanger with
an I-beam structure is U.S. Pat. No. 5,129,557 which is
incorporated herein by reference.
[0004] I-beams, whether used for building, machinery or garment
hanger construction, follow well recognized and well studied
scientific rules of bending, shear and twisting stress loading and
deflection. When using I-beams for building and machinery
construction, a design engineer typically calculates the required
thicknesses and breadths of the I-beam's webs and flanges, with
size, weight and cost being secondary to strength and safety
requirements. In the field of garment hanger construction, attempts
have been made to utilize this knowledge of I-beam construction;
however, it is not feasible to simply make the hangers larger,
thicker or increase flanges of an I-beam body shape, primarily
because of the increased cost of material and manufacture in this
very high volume industry and also because added weight or size is
undesirable.
[0005] The present invention involves the development of a
different and non-traditional beam structure, which provides the
desired strength and resistance to twisting and buckling, with the
quantity of plastic required per hanger and the cycle time for
manufacture essentially the same or less than what is required for
prior art I-beam hangers.
SUMMARY AND OBJECTS OF THE NEW INVENTION
[0006] One object of this invention is to provide a new molded
garment hanger which has greater strength and resistance to
buckling when loaded with a garment than prior hangers which were
considered unreliable. Buckling in this application means excessive
bending primarily in the forward and downward directions, which may
be forward twisting. It is an object to provide hangers that resist
such buckling and thus support and present the garments in a more
desirable manner.
[0007] It is a further object to provide buckling resistant molded
garment hangers which have generally the same outer dimensions as
prior art hangers, and preferably have similar cross-sectional area
which means they would contain essentially the same amount of
plastic.
[0008] It is a still further object in certain embodiments of the
invention that the new hangers have cross-sections that are
generally uniform.
[0009] It is an additional object that the new hangers have greater
resistance to buckling than prior art hangers having I-beam or
M-beam construction.
[0010] Another object is to provide molded hangers that are
economical in regard to cost of material and cost of
manufacture.
[0011] In summary, it is an object to provide molded hangers that
are better in resistance to buckling and in other regards than
prior art hangers.
[0012] Hangers of the new invention may have a variety of known
body part shapes including but not limited to a straight horizontal
beam shape, rounded shoulders shape, and a low profile shape with
opposite shoulders elevated above the central section. In a first
embodiment the new invention is an injection molded plastic garment
hanger having a straight horizontal beam body part with an S-shape
cross-section. Load and displacement plots from test results reveal
that a beam having this new S-shape cross-section has greater
strength and resistance to buckling than do beams of generally
equal cross-sectional area in prior art I-beam or prior art M-beam
configurations.
[0013] In this first preferred embodiment the S-shape cross-section
has upper and lower curves which together form a continuous central
web. Each of said upper and lower curves has a free end formed as a
generally horizontally extending foot with an oppositely extending
heel. The foot and heel at the top and bottom of the new S-shape
correspond generally to the top and bottom flanges of a prior art
I-beam. The web and the flanges of the new S-shape have generally
uniform thickness.
[0014] Within this S-beam cross-section is a central longitudinal
axis which divides the cross-section, such that there is
essentially equal lateral extension or equal area on each side of
the central vertical axis. Corresponding to this central vertical
axis of the S-shape is a central vertical plane extending
lengthwise of the S-beam. With respect to this central vertical
plane, the toe of the lower flange foot, the upper curve of the web
and the heel of the upper flange all extend the same distance
forward, thus establishing a front plane of the beam. The toe of
the upper flange foot, the lower curve of the web and the heel of
the lower flange all extend the same distance rearward of the
central vertical plane, thus, establishing a rear plane of the
beam.
[0015] A garment hanger using the new S-beam has a typical
rack-engaging hook extending from the top of the beam. This
preferred embodiment also has spring clamps at the opposite ends of
the beam respectively for engaging garments, and has spaced apart
fingers extending downwardly from the bottom edge of the beam for
engaging the garment.
[0016] The first preferred embodiment may be summarized as an
injection molded plastic garment hanger comprising:
[0017] a. a hook having a top part, a stem extending downward from
said top part and a bottom part, and
[0018] b. a body part formed as a generally horizontally extending
beam having a central part and arms extending oppositely from said
central part and terminating in opposite ends,
[0019] said bottom part of said hook being joined to said central
part of said beam,
[0020] said beam's central part and arms comprising a web having
upper and lower portions and extending lengthwise of said beam and
extending downward from said hook,
[0021] said web in cross-section defining a generally S-shape
comprising upper and lower portions thereof, and
[0022] said web's upper portion having a top part which extends
forwardly as a top front flange of said beam terminating in a font
edge, and said web's lower portion having a bottom part which
extends rearwardly as a bottom rear flange of said beam terminating
in a rear edge.
[0023] In a further embodiment of the new hanger, said continuous
upper and lower curves of the S-shaped cross-section define a web
with top and bottom flanges which extend generally horizontally in
opposite directions respectively, each of said flanges comprising a
foot having a toe portion that extends forwardly and a heel portion
that extends rearwardly.
[0024] In a still further embodiment of the new hanger said S-shape
has a generally central vertical axis corresponding to a central
vertical plane of said S-beam, wherein said top and bottom flanges
extend forwardly and rearwardly substantially the same distances
respectively from said central vertical plane.
[0025] In a second preferred embodiment of the new garment hanger,
the straight horizontal beam body part has a modified Z-shape
cross-section formed as an upper Z directly above a lower Z, where
the bottom horizontal foot of the upper Z serves as the top
horizontal foot of the lower Z. These top and bottom feet
correspond to transverse flanges in an I-beam. The material between
the top and bottom horizontal feet is a zig-zag web which has
generally uniform thickness. The top and bottom feet have thickness
similar to that of the web thickness. In this double Z combination
beam the upper and lower Zs share a common central vertical axis,
which is not an axis of symmetry because of the nature of the
double Z shape.
[0026] The Z-beam hanger, in summary, comprises:
[0027] a. a hook having a top part, a stem extending downwardly
from said top part and a bottom part, and
[0028] b. a body part formed as a beam extending transversely of
said hook, said beam having a central part and arms extending
oppositely from said central part and terminating in opposite
ends,
[0029] said bottom part of said hook being joined to said central
part of said beam,
[0030] said beam's central part and arms comprising a web having
upper and lower portions extending lengthwise of said beam and
extending downward from said hook,
[0031] said web in cross-section defining a generally Z-shape
comprising a stem, with upper and lower portions of said web
forming respectively a top front flange extending forwardly and
terminating in a front edge, and a bottom rear flange extending
rearwardly and terminating in a rear edge.
[0032] In a still further embodiment of the Z-shape hanger the web
in cross-section comprises a set of upper and lower Z-shapes, where
each Z-shape has upper and lower generally horizontal feet, and
where the lower foot of the upper Z-shape comprises the upper foot
of the lower Z-shape, this common foot being an intermediate flange
between said top front and bottom rear flanges.
[0033] In a further embodiment said upper and lower feet define
upper and lower flanges respectively of said Z-beam, and said
shared foot defines a middle flange.
[0034] As indicated above, the S-beam and Z-beam cross-sections may
be incorporated into various body part shapes including a hanger
having traditional rounded shoulder hanger and a hanger having low
profile shoulders that rise above a central part.
[0035] The low profile hanger, in summary, comprises:
[0036] a. a hook having a top and bottom parts, and
[0037] b. a body part formed as a transversely extending beam
having a central part and shoulder parts extending outward from
said central part and terminating in opposite ends,
[0038] said bottom part of said hook being joined to said central
part of said beam,
[0039] said shoulder parts being at an elevation above said central
part, wherein said central part and said shoulder parts define a
generally low profile shape, said beam's central part and shoulder
parts comprising a web extending lengthwise of said beam and
extending downward from said hook,
[0040] said web in cross-section defining a generally S-shape
comprising upper and lower portions thereof,
[0041] said web's upper portion having a top part which extends
forwardly as a top front flange of said beam terminating in a front
edge, and said web's lower portion having a bottom part which
extends rearwardly as a bottom rear flange of said beam terminating
in a rear edge.
[0042] On comparing stress/displacement plots for the new S-beam
and the prior art I-beam, the results for straight horizontal test
beams demonstrate that the S-beam shows less twisting and buckling
deflection from the same vertical loading. Details of the loading
and deflection plots are presented below, which demonstrate
impressively how the S-beam is substantially stronger than the
I-beam against buckling loads, despite the fact that both beams
have essentially the same cross-sectional areas, consume
essentially the same quantity of plastic, and have about the same
height.
[0043] Further features and advantages of the invention as well as
the structure and operation of various embodiments of the present
invention are described in detail below with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a front elevational view of a first embodiment of
the new garment hanger having an S-beam cross-section,
[0045] FIG. 2 is a rear elevational view of FIG. 1,
[0046] FIG. 3 is a sectional view taken along line 3-3 in FIG.
1,
[0047] FIG. 4 is a sectional view similar to FIG. 3 of a second
embodiment of the new garment hanger having a Z-beam cross-section,
taken along line 4-4 in FIG. 5,
[0048] FIG. 5 is a fragmentary front elevational view of the beam
of the second embodiment hanger represented by FIG. 4,
[0049] FIG. 6 is a rear elevational view of FIG. 5,
[0050] FIG. 7 is a schematic perspective view showing vertical
cantilever loading of a prior art I-beam having restraints at one
end in the vertical and transverse directions,
[0051] FIG. 8 is a schematic perspective view of the I-beam of FIG.
7 showing Y-displacements (vertical) from vertical loading,
[0052] FIG. 9 is a schematic perspective view of the I-beam of FIG.
7 showing Z-displacement (transverse/horizontal) from vertical
loading,
[0053] FIG. 10 is a schematic perspective view 180.degree. rotated
about a vertical axis from FIG. 7, showing buckling in a forward
twisting orientation from vertical loading of the I-beam of FIG.
7,
[0054] FIG. 11 is a schematic perspective view showing vertical
cantilever loading of the S-beam for use in the garment hanger of
FIGS. 1-3,
[0055] FIG. 12 is a schematic perspective view (load plot) showing
Y-displacement (vertical) from vertical loading of the S-beam of
FIG. 11,
[0056] FIG. 13 is a schematic perspective view (load plot) showing
Z-displacement (transverse/horizontal) from vertical loading of the
S-beam of FIG. 11,
[0057] FIG. 14 is a schematic perspective view showing buckling in
a forward twisting orientation from vertical loading of the S-beam
of FIG. 11,
[0058] FIG. 15 is a schematic perspective view showing vertical
cantilever loading of the Z-beam for use in the garment hanger of
FIGS. 4-6,
[0059] FIG. 16 is a schematic perspective view (load plot) showing
Y-displacement (vertical) from vertical loading of the Z-beam of
FIG. 15,
[0060] FIG. 17 is a schematic perspective view (load plot) showing
Z-displacement (transverse/horizontal) from vertical loading of the
Z-beam of FIG. 15,
[0061] FIG. 18 is a schematic perspective view (load plot) similar
to FIG. 10 showing buckling in a forward twisting orientation from
vertical loading of the Z-beam of FIG. 15,
[0062] FIG. 19 is a top front perspective view of a further
embodiment showing a rounded shoulder hanger with an S-shape
cross-section,
[0063] FIG. 20 is a schematic front elevation view of a still
further embodiment showing a first low profile hanger with an
S-shape cross-section,
[0064] FIG. 21 is a schematic front elevation view of a further
embodiment showing a second low profile hanger with an S-shape
cross-section, and
[0065] FIGS. 22-26 are sectional views taken along lines 22-22,
23-23, 24-24, 25-25 and 26-26 respectively in FIG. 21.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0066] A. The S-beam Garment Hanger
[0067] The new S-beam garment hanger 10, as seen in FIGS. 1 and 2,
as a one-piece injection molded product, has a typical hook 11 at
the top and a body portion 12 formed basically as a horizontal
beam. There is resilient clamp 14 at each end of beam 12 and a
plurality of finger-like projections 16 spaced apart and extending
downwardly from beam 12. Each clamp 14 has a pair of jaws, the
inner jaw 18 being relatively rigid due to the supporting web 19
and the outer jaw 20 being resiliently pivotable away from jaw 18,
to receive and hold a strap or other part of a garment. Each of the
projections 16 has a supporting web 16A which strengthens and
stiffens it. The hook 11 has an I-beam cross-section which enhances
its strength.
[0068] Beam 12 of hanger 10, shown in cross-section in FIG. 3, has
a modified S-shape. More specifically, this cross-section defines a
central upright S-shaped web 22 formed by a set of upper and lower
continuous reverse curves 22A, 22B respectively.
[0069] The bottom of web 22 is formed as a horizontally extending
foot 23 having a toe portion 24 and an oppositely extending heel
portion 25. At the top of web 22 is a similar but opposite foot 26
having a toe portion 27 and an oppositely extending heel portion
28. A central vertical axis Y1-Y1 divides this cross-section into
essentially equal but non-symmetrical halves. Corresponding to this
central vertical axis is a central vertical plane extending
lengthwise through the S-beam.
[0070] In the cross-section as seen in FIG. 3, there are indicated
front and rear planes P1 and P2 respectively that are parallel to
the central vertical plane Y1-Y1. The top flange heel 28, the upper
curve front part 22 and the bottom flange toe 24 all extend forward
to said front plane P1. Similarly, but in reverse, the top flange
toe 27, the lower curve rear part 22B and the lower flange heel 25
all extend rearward to said rear plane P2. As seen, the top and
bottom flange and reverse curved web between said flange all have
generally the same constant wall thickness, except for the tips of
the toes and heels which are rounded to a lesser thickness. The
height of the cross-section is in the range of 0.395 to 0.405
inches and the breadth is in the range of 0.183 to 0.193 inches,
with a ratio of about 2.047 to 2.213 or about 2:1.
[0071] B. The Z-beam Garment Hanger
[0072] The second embodiment of the garment hanger of the present
invention is called the Z-beam hanger, which is very similar to the
above-described S-beam hanger, except for the fact that its
horizontal beam defines in cross-section a set of upper and lower Z
elements, 32 and 33 respectively, as seen in FIGS. 4, 5 and 6. The
upper Z element 32 has upper horizontal foot 34, angled web 35 and
lower foot 36; the lower Z element 33 has lower foot 37, angled web
38 and upper foot 39 which is the same as lower foot 36 of the
upper Z element. A central vertical axis Y2-Y2 divides this
cross-section into two essentially equal but non-symmetrical
halves. Corresponding to the central vertical axis Y2-Y2 is a
central vertical plane extending lengthwise through the Z-beam.
[0073] In the cross-section as seen in FIG. 4, there are indicated
front and rear planes P3 and P4 respectively that are parallel to
the central vertical plane Y2-Y2. The front edges of the top flange
34, the middle flange 36, 39 and the bottom flange 37 all extend
forward to plane P4. Similarly, but in reverse, the rear edges of
the top, middle and bottom flanges all extend rearward to plane P4.
The wall thicknesses of these three flanges and of the inclined web
parts 35 and 38 all have generally the same uniform thickness.
[0074] The load or stress on these hangers will vary depending on
where and how a garment is attached and how the garment's weight is
distributed. The above-described I-beam, S-beam and Z-beam elements
have been tested under loading conditions simulating actual garment
hanger loading, with the results shown in FIGS. 7-14 and discussed
in later sections herein. For these tests the three beams of
different cross-sectional shapes, namely I-beam, S-beam and Z-beam,
each had essentially the same height and the same cross-sectional
area and thus the same mass of plastic.
[0075] C. An S-beam Rounded Shoulder Hanger
[0076] FIG. 19 shows a rounded shoulder S-beam hanger 70 as a
further embodiment of the present invention. This hanger has
central part 71 with traditional rounded shoulders 72 on each side
and a hook 73 at the top. The central part 71 and the shoulders 72
are formed as a continuous beam 73 of S-shape cross-section,
generally similar to the S-shape cross-section described above in
connection with the straight beam hangers. In this S-beam structure
the upper part 73a of the beam 73 curves outward toward the viewer,
and the lower part 73b curves away from the viewer. This hanger has
optional notches or recesses 74 at the tops of the shoulders to
engage straps or other parts of garments.
[0077] D. An S-beam Low Profile Hanger
[0078] FIG. 20 shows a low profile S-beam hanger 75 having a hook
76, a body part formed as a continuous beam comprising a central
section 77 and arms 78 which rise to an elevation above the central
part, and an array of clips or clamps 79 at the end of each arm.
The S-shaped cross-section, generally as seen in earlier described
embodiments herein, is employed along the length of the body part,
namely along the central section 77 and along the arms 78. The line
77a schematically represents the frontward and rearward curvatures
of the S-shape form of this beam. Further detail construction of
this S-shape beam are seen in FIGS. 3 and 11; however, the height
and proportions of the S-shape vary slightly along the length of
the beam. The clips or clamps are conventional which include both
rigid and resilient types
[0079] E. A Second S-beam Low Profile Hanger
[0080] FIG. 21 shows a second embodiment of a low profile S-beam
hanger 80 having a hook 81, a body part formed as a continuous beam
comprising a central section 82 and shoulders 83 which are elevated
from the central section, and hooks, clips or clamps 84 extending
downward from the shoulders 83. The S-shape cross-section,
generally as seen in earlier described embodiments herein, is
employed along the length of the body part, namely along the
central section 82 and along the shoulders 83. The line 82a
represents the transition area between the frontward and rearward
curvatures of the S-shape form of this beam. The cross-section of
this S-beam varies along its length, as indicated by the sectional
views in FIGS. 22-26, where FIG. 22 has the tallest section, FIG.
24 has the shortest section and all sections have substantially the
same front-to-rear depth. As evident in FIG. 22, the upper and
lower flanges 85, 86 respectively are substantially never parallel
to each other, as the beam tapers slightly along each section of
its length. Further detail construction of this S-shape beam is
seen in FIGS. 3 and 11.
[0081] Following below are descriptions of load/displacement/stress
plots for a prior art I-beam as a point of reference, and for the
new S-beam and the new Z-beam. Each of these plots utilizes an X,
Y, Z coordinate system where Y represents the vertical load
direction and vertical displacement axis, Z represents the lateral
load direction and lateral displacement axis, and X represents the
beam's longitudinal axis.
[0082] F. I-beam: Load/Displacement/Stress Plots
[0083] In FIG. 7 the I-beam 40 in a cantilever loading
configuration has its first end 42 fixed by Z, X and Y restraints
and its distal or free end 44 loaded with a one pound force F1 in
the Y or vertical direction. This beam is five inches long and has
cross-sectional area A1 and predicted weight of 0.006334 lbs.
[0084] FIG. 8 shows the vertical load and vertical displacement
plot of the I-beam 40 of FIG. 7 with the one pound vertical force
F1 as seen in FIG. 7. The beam 40 in a non-loaded state is
represented as the semi-transparent structure 40A, and in the
loaded state is represented by the solid structure 40B. This format
of transparent lines for non-loaded versus solid lines for loaded
is used in connection with the remaining load/displacement/stress
plots herein. Displacement D1 at the distal end 44 under this
vertical load was 0.257 inches which produced a 2,153 psi von Mises
stress.
[0085] FIG. 9 shows the vertical load and lateral displacement plot
of 0.000241 inches in the Z-direction of the I-beam 40, where the
beam has deflected laterally as a result of the vertical load.
[0086] FIG. 10 shows the buckling displacement in both Y and Z
directions from a buckling load of 2.396 lbs.
[0087] G. S-beam: Load/Displacement/Stress Plots
[0088] FIG. 11 shows an S-beam 50 in a cantilever loading
configuration with its first end 52 fixed by Z, X and Y restraints
and its distal or free end 54 loaded with a one pound force F2 in
the vertical direction. This beam has length of five inches and
cross-sectional area A2 and predicted weight of 0.006022 lbs.,
essentially the same cross-sectional area A1 and weight as that of
the I-beam of FIG. 7.
[0089] FIG. 12 shows the vertical load and vertical displacement
plot of the S-beam 50 with the one pound vertical force F2 as shown
in FIG. 11. Displacement D2 at the distal end 54 under this
vertical load was 0.3027 inches which produced a 6.206 psi von
Mises stress. As noted earlier, the non-loaded beam is represented
by the semi-transparent structure, and the loaded beam is
represented by the solid structure.
[0090] FIG. 13 shows for the S-beam 50 the vertical load F3 and
lateral displacement plot in the Z-direction, with displacement
D3=0.2015 in.
[0091] FIG. 14 shows the buckling displacement in both Y and Z
directions, from a buckling load of 2.901 lbs.
[0092] H. Z-beam: Load/Displacement/Stress Plots
[0093] FIG. 15 shows a Z-beam 60 in a cantilever loading
configuration with its first end 62 fixed by Z, X and Y restraints
and its distal or free end 64 loaded with a one pound force F3 in
the vertical direction. This beam has length of five inches and
cross-sectional area A3 and predicted weight of 0.006374 lbs.,
essentially the same as cross-sectional areas A1 and A2 and weights
of the S-beam of FIG. 11 and of the I-beam of FIG. 7,
respectively.
[0094] FIG. 16 shows the vertical load and vertical displacement
plot of the Z-beam 60 with the one pound vertical Force F3 shown in
FIG. 15. Displacement D4 at the distal end 64 under the vertical
load was 0.308 inches, which produced a 2,557 psi von Mises
stress.
[0095] FIG. 17 shows for the Z-beam the vertical load and lateral
displacement plot in the Z direction, with displacement D5=0.04608
in.
[0096] FIG. 18 shows for the Z-beam a buckling displacement in both
Y and Z directions from a buckling load 0.875 lbs.
[0097] Table 1 shown below displays a comparison of the
above-described displacement plots for the I-beam, S-beam and
Z-beam, where all of these beams have the same length, load and
cross-sectional area, but have different cross-sectional
configurations. As seen in Table 1, when subject to the one pound
vertical loading:
[0098] a. Y-Displacement: the I-beam had the least vertical (y)
displacement (0.257 in.), the S-beam was next (0.303 in.), and the
Z-beam had the greatest displacement (0.308 in.)
[0099] b. Z-Displacement: the I-beam had the least lateral (z)
displacement (0.000 in.), the Z-beam was next (0.046 in.), and the
S-beam had the greatest (0.202 in.), and
[0100] c. Buckling Load: the S-beam supported the greatest buckling
load 2.901 lbs., the I-beam was next with 2.396 lbs, and the Z-beam
supported the least with 2.016 lbs.
[0101] Table 2, as expected, shows the S-beam (which supported the
greatest buckling load) had the lowest von Mises stress of 1,426
psi compared to 1,872 psi for the I-beam and 1,755 psi for the
Z-beam.
1TABLE 1 Summary of Maximum Vertical Load Results Y- Z- Support End
Buckling Displacement Displacement Von Mises Stress Load Design
(inch) (inch) (psi) (lbs.) I-beam 0.257 0.000 1,495 2.396 S-beam
0.303 0.202 2,153 2.901 Z-beam 0.308 0.046 1,912 2.016
[0102]
2TABLE 2 Summary of Maximum Lateral Load Results Z-Displacement Von
Mises Stress Design (inch) (psi) I-beam 0.743 1,872 S-beam 0.457
1,426 Z-beam 0.652 1,755
[0103] In all these beams the plastic was Acrco HM20Z1
Polypropylene having a modulus of 220,000 psi.
[0104] These results demonstrate that as compared to I-beams and
Z-beams, the S-beam has significantly greater buckling strength. As
noted above, all three beams had approximately the same
cross-sectional area and thus used approximately the same amount of
plastic.
[0105] While various embodiments of the present invention have been
described above, it should be understood that they have been
presented by way of example, and not limitation. It will be
apparent to persons skilled in the relevant art that various
changes in form and detail can be made therein without departing
from the spirit and scope of the invention. Thus the present
invention should not be limited by any of the above-described
exemplary embodiments, but should be defined only in accordance
with the following claims and their equivalents.
* * * * *