U.S. patent application number 12/725149 was filed with the patent office on 2010-07-08 for portable flexible and extendable drain pipe.
Invention is credited to E. Michael Boettner, Billy J. Hall, Frank T. Hoffman.
Application Number | 20100170589 12/725149 |
Document ID | / |
Family ID | 37871992 |
Filed Date | 2010-07-08 |
United States Patent
Application |
20100170589 |
Kind Code |
A1 |
Boettner; E. Michael ; et
al. |
July 8, 2010 |
Portable Flexible and Extendable Drain Pipe
Abstract
A flexible collapsible corrugated drain pipe has a corrugation
structure that permits a tight bending radius and relatively facile
collapsing and expansion of corrugations, thereby permitting
convenient manipulation and installation of drain pipe and
packaging, display, storage and transportation of the collapsed
pipe sections.
Inventors: |
Boettner; E. Michael;
(Cleveland, TN) ; Hall; Billy J.; (Cleveland,
TN) ; Hoffman; Frank T.; (Cleveland, TN) |
Correspondence
Address: |
DOUGLAS T. JOHNSON;MILLER & MARTIN
1000 VOLUNTEER BUILDING, 832 GEORGIA AVENUE
CHATTANOOGA
TN
37402-2289
US
|
Family ID: |
37871992 |
Appl. No.: |
12/725149 |
Filed: |
March 16, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11446026 |
Jun 2, 2006 |
7677271 |
|
|
12725149 |
|
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|
60714772 |
Sep 8, 2005 |
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Current U.S.
Class: |
138/119 ;
138/121 |
Current CPC
Class: |
F16L 11/15 20130101;
F16L 37/084 20130101 |
Class at
Publication: |
138/119 ;
138/121 |
International
Class: |
F16L 11/00 20060101
F16L011/00 |
Claims
1. A flexible collapsible corrugated drain pipe comprising a first
end section, an intermediate section of annular corrugations and a
second end section, in which the corrugations comprise smaller
rings joined by tuck walls connected at tuck angles to larger rings
so that tuck walls are hingedly connected at larger rings to static
walls extending at static angles and connecting the larger rings to
next adjacent smaller ring where the ratio of the static angles to
the tuck angles is less than 1.20.
2. The flexible collapsible corrugated drain pipe of claim 1
wherein the wall thickness is less than about 0.04 inches.
3. The flexible collapsible corrugated drain pipe of claim 1 having
an expanded length greater than 10 feet.
4. The flexible collapsible corrugated drain pipe of claim 1
wherein the ratio of the diameter of the larger rings to the
diameter of the smaller rings is less than 1.20.
5. The flexible collapsible corrugated drain pipe of claim 1
wherein the ratio of the bend radius of the pipe to the diameter of
the larger rings of the pipe is less than 1.4.
6. The flexible collapsible corrugated drain pipe of claim 1 having
a collapse ratio greater than 5.
7. The flexible collapsible corrugated drain pipe of claim 1
wherein the ratio of the length of the static wall to the length of
the tuck wall is less than 1.3.
8. A flexible collapsible corrugated drain pipe having a corrugated
annular section comprised of a corrugation with a first smaller
ring having a minimum diameter connected by a tuck wall to a larger
ring having a maximum diameter and a static wall connecting the
larger ring to a second smaller ring wherein the ratio of the
maximum diameter to the minimum diameter is less than 1.2 and
having a collapse ratio greater than 5.
9. The flexible collapsible corrugated drain pipe of claim 8
wherein the ratio of the length of the static wall to the length of
the tuck wall is less than 1.3.
10. The flexible collapsible corrugated drain pipe of claim 8
wherein the corrugated annular section has a bend radius such that
the ratio of the bend radius to the maximum diameter is less than
1.3.
11. The flexible collapsible corrugated drain pipe of claim 8
having an expanded length greater than then feet.
12. The flexible collapsible corrugated drain pipe of claim 8
wherein the thickness of each of the tuck walls and the static
walls is less than 0.04 inches.
13. A flexible collapsible corrugated drain pipe comprising: (a) a
first end section; (b) a second opposite end section; (c)
corrugated annular section intermediate said first and second end
sections wherein said corrugated section has corrugations with:
minor diameter rings joined to first ends of tuck walls; said tuck
walls having second opposite ends joined at a tuck angle to major
diameter rings; static walls having first ends joined to major
diameter rings opposite the tuck walls, at a static angle, said
static walls having second opposite ends joined to minor diameter
rings opposite the tuck walls; wherein the ratio of the size of the
major diameter rings to the minor diameter rings is less than 1.2
and wherein the corrugated annular section has a bend radius such
that the ratio of the bend radius to the diameter of the major
diameter rings is less than 1.3.
14. The flexible collapsible corrugated drain pipe of claim 13
wherein the force needed to expand a tuck wall from a collapsed
position against an adjacent static wall is less than about twelve
pounds.
15. The flexible collapsible corrugated drain pipe of claim 13
wherein the ratio of the static angles to the tuck angles is less
than 1.20.
16. The flexible collapsible corrugated drain pipe of claim 13
having a collapse ratio greater than 5.
17. The flexible collapsible corrugated drain pipe of claim 13
wherein the ratio of the length of the static wall to the length of
the tuck wall is less than 1.3.
18. The flexible collapsible corrugated drain pipe of claim 13
having an expanded length greater than ten feet.
19. The flexible collapsible corrugated drain pipe of claim 13
wherein the thickness of each of the tuck walls and the static
walls is less than 0.04 inches.
20. The flexible collapsible corrugated drain pipe of claim 13
wherein in an expanded position, the sum of the tuck angle and the
static angle at a major diameter ring is at least 92.degree. and
the static angle is at least 3.degree. larger than the tuck angle.
Description
[0001] The present application is a continuation of U.S. patent
application Ser. No. 11/446,026 filed Jun. 2, 2006, which claims
priority to U.S. Provisional Patent Application Ser. No. 60/714,772
filed Sep. 8, 2005, which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to plastic drain pipe. In particular,
the invention relates to a drain pipe particularly designed to
provide a flexible and extendable pipe and to facilitate both the
packaging and the connections of pipe segments.
BACKGROUND OF THE INVENTION
[0003] This invention is directed to providing an improved drain
pipe, and particularly to providing an improved drain pipe of the
type used in the drainage of soil and the transportation of surface
water by gravity for agricultural, septic, residential, civil
construction, or recreational purposes. Typical product sold to
residential end users is nominally four inches in diameter and sold
in ten foot straight lengths or in rolls of 50 to 300 feet in
length. Typically, the color is black and the material is high
density polyethylene (HDPE). The plastic drain pipe is corrugated
on the exterior and may or may not have a smooth interior wall.
Both straight lengths and rolls of the corrugated pipe are not
collapsible, and as a result are bulky. Some types of corrugated
pipe require connectors to join pieces or elbows to cause the pipe
to hold a curved position. Pipe sold in rolls tends to retain a
memory making it difficult to place in a trench without elbows or
weighting the pipe sections down with ballast such as rocks or a
building block. Both the straight lengths and rolled corrugated
pipe need to be cut to length. Corrugated pipe sections that are
adapted to connect with adjacent sections often utilize proprietary
connecting configurations and are rendered inoperable with pipe
sections manufactured by other suppliers.
[0004] In the field of gutter downspouts, collapsible corrugated
tubing has been utilized by Gutter World, Inc. as reflected in U.S.
Pat. Nos. 5,813,701; 5,915,735; 6,041,825; and 6,223,777. These
downspout extensions have male and female rectangular end sections
to connect with gutter downspouts and adjacent extensions. In
addition, the corrugated collapsible downspout extension pipes have
only been used in relatively short lengths, approximately six to
eight feet long when fully extended, have utilized thick wall
corrugations, and have utilized a profile that did not optimize
either the collapse ratio or the bend radius of the product. It is
believed that the downspout extension products have only been sold
in a straight collapsed configuration which, with non-collapsible
end sections, results in a longitudinal product between two and
three feet in overall length.
[0005] Gutter World, Inc. has also manufactured a rectangular
profile collapsible gutter spout tubing in lengths of less than
about two feet when fully extended. Although this rectangular
product approximates some measurements in its straight walled
corrugations to the annular corrugations of the present invention,
rectangular corrugated products have inherently irregular wall
thicknesses. When fabricated on a corrugator, the midpoints of
straight walls are thicker than the walls near corners, and thus
the entire tubing must be made with relatively thick walls to
ensure adequate coverage in the corner areas. This leads to thicker
midpoints of walls in comparison to the corners, causing the
resulting rectangular product to collapse irregularly.
[0006] Most other collapsible corrugated tubing has been
constructed for medical uses in smaller diameter sizes such as
about 1 to 1.5 inches. These tubings are much smaller and lighter
than drainage tubing, which typically has a diameter at least about
3 inches and must possess some rigidity so that it is not crushed
when buried in a trench. Due to the relatively small sizes and thin
walls of these prior collapsible tubes, it has been possible to
work with small tubes even when they were not optimized for
portability and ease of manipulation.
SUMMARY OF THE INVENTION
[0007] It is therefore an object of the invention to provide a
collapsible drain pipe that may provide one or more of the
following benefits: ease of use and handling; improved corrugation
profile for manufacturing and performance characteristics; and
convenient packaging and storage.
[0008] In furtherance of these objectives, a collapsible corrugated
drain pipe is disclosed with integrated male and female cuff
sections at opposed ends and having therebetween a central section
of collapsible and extendable rings alternating between a large
diameter and a small diameter to allow the pipe to be fixedly
directed in desired orientations, extended or reduced in length,
and to be folded and packaged for convenient sale and handling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention may be better appreciated with reference to
the following drawings in which like numerals refer to like
elements throughout the several views:
[0010] FIG. 1 is a side view of an embodiment of the present
invention bent to demonstrate the flexibility of the tubing.
[0011] FIG. 2A is a side sectional view of the female end section
of the drain pipe shown in FIG. 1.
[0012] FIG. 2B is a perspective view of the female end section of
the drain pipe shown in FIG. 2A.
[0013] FIG. 2C is a side sectional view of the male end section of
the drain pipe shown in FIG. 1.
[0014] FIG. 2D is a perspective view of the male end section of the
drain pipe shown in FIG. 2C.
[0015] FIG. 3A is an enlarged view of expanded corrugations of a
prior art large diameter collapsible gutter extension in
isolation.
[0016] FIG. 3B is an enlarged view of expanded corrugations of the
drain pipe of FIG. 1 in isolation.
[0017] FIG. 3C is a sectional view of the corrugations of the drain
pipe of FIG. 1 taken along the line C-C.
[0018] FIG. 3D is an enlarged view of collapsed corrugations of the
drain pipe of FIG. 3C.
[0019] FIG. 3E is a side view of prior art corrugations for small
diameter tubing including a bent tuck edge.
[0020] FIG. 3F is a prior art side view of rectangular gutter
tubing.
[0021] FIG. 3G is an end view of the corrugations of FIG. 3F.
[0022] FIG. 4A is a representative packaging design for collapsible
drain pipe according to the present invention.
[0023] FIG. 4B is an alternative packaging design for collapsible
drain pipe according to the present invention.
[0024] FIG. 4C is another alternative packaging design for a
collapsible drain pipe according to the present invention.
[0025] FIG. 5 is an illustration of the folding and securing of a
drain pipe according to the present invention for use in the
packaging of FIG. 4A or 4B.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring now to the drawings, FIG. 1 depicts an exemplary
drain pipe 10 according to the present invention with a first male
end section such as cuff 20 and an opposite female end section such
as cuff 30 positioned about an intermediate collapsible portion 12
comprised of a plurality of annular corrugations of alternating
smaller, minimum or minor diameter rings 16 separated by larger,
maximum or major diameter rings 17 being respectively connected by
alternating static walls 51 and tuck walls 52 to permit a section
of the pipe to be in: an extended state 13; a collapsed state 15;
or a curved or directed state 14. An enlarged view of expanded
corrugations is shown in FIG. 3B, and an enlarged view of collapsed
corrugations is shown in FIGS. 3C and 3D. Generally, the drain pipe
is in a compressed state when the corrugations are collapsed so
that tuck sides 52 are folded inward against static sides 51 as
shown in FIG. 3D. The drain pipe is in expanded state when tuck
sides 52 are folded outward apart from static sides 51 to the
extent possible, generally achieving an angular orientation between
the tuck and static sides of about 90.degree., and possibly even a
slightly greater angular orientation. Of particular note are
tooling points, shown as uncollapsible rings 19 with reverse arch
shapes, which are desirable for aiding in the manipulation of the
tubing for packaging.
[0027] Turning then to FIGS. 2A, and 2B, a female end section such
as cuff 30 is shown with interior channel 32 defined by externally
sloped wall 34 and side wall 33 which is nearly normal to the
longitudinal axis 18 of the cuff 30. A transition section 31
connects cuff 30 to the expandable portion of the pipe 10, where
cuff 30 will typically join either a small ring 16 or large ring
17. The walls of cuff 30 are reinforced by structural supports 35,
and toward the end of the cuff 30 beyond channel 32 is an end lip
36. The channel 32 preferably extends annularly about the entire
interior of cuff 30 so that it may engage with detents or flanges
of a variety of configurations of male end sections manufactured by
drain pipe producers.
[0028] FIG. 2B illustrates a male end section such as male cuff 20
again having a transition section 21 to engage with the expandable
section of the pipe at a small ring 16 in the illustrated diagram.
Detents 22 are oriented about the cuff 20, preferably separated by
90.degree. of angular orientation. Detents are formed by forward
sloping sides 24 and rear sides 23 that are nearly normal to the
longitudinal axis of cuff 20. Forward of the detents 22 is the
front lip. It will be seen that pipe sections may be joined by
interfitting front lip 26 of male cuff 20 within the end lip 36 of
female cuff 30 and pushing male and female cuffs together until
detents 22 are engaged within channel 32 of female cuff 30.
Alternative detent configurations are possible on the male cuff,
and the illustrated configuration is selected in order to provide
the capability of engaging with a variety of companies' drain pipe
fittings.
[0029] FIGS. 3A-3G illustrate a variety of corrugation styles
utilized in collapsible tubing. FIGS. 3A and 3E-G illustrate prior
art. The prior art corrugation design in FIG. 3A is utilized in the
commercial embodiments of the Flex-A-Spout brand product sold by
Gutter World, Inc. These corrugations consist of a tuck wall 42
connecting a smaller diameter ring 44 to a larger diameter ring 45
and having a hinge 43 connecting to a static wall 41, the static
wall connecting the larger diameter ring 45 to the next smaller
diameter ring 44. The illustrated hinge 43 is a bubble hinge
intended to make the folding of the tuck wall 42 against the static
wall 41 easier and require less force. The compression ratio of the
tubing is determined by the tuck and static angles .alpha., and
.beta., as well as the radius of the hinge 43, the length of the
tuck side wall 42 and the length of the static side wall 41. In the
typical Flex-A-Spout configuration, the smaller ring inner diameter
is 3.664 inches, the length of the tuck wall 42 including the 0.009
inch height of bubble hinge 43 is 0.504 inches, and the length of
the static wall 41 is 0.704 inches. The larger diameter ring 45 has
an inner diameter of 4.590 inches. In expanded state, the tuck wall
42 is at an angle of about 49.93.degree. with the longitudinal axis
18 of the pipe 10 so that the tuck angle .alpha. is 40.07.degree..
The static side is at an angle of 39.1.degree. with the
longitudinal axis 18 so that the static angle .beta. is
50.9.degree.. The sum of .alpha. and .beta. is about 91.degree..
The expanded width of a single corrugation is 1.0 inches.
[0030] A greater variation in size between larger ring 45 diameter
and smaller ring 44 diameter produces threefold effects. First, the
longer distance between interior pivot hinges 47 and outer hinges
43 means that when manufacturing corrugated tubes, the HDPE, or
other plastic being applied, will tend to be thicker at the
interior hinges 47 and thinner at the outside hinges 43. Indeed, at
the interior hinges 47 the tubing of FIG. 3A achieves a thickness
near 0.035 inches, but at the outside hinges 43 thins to near 0.020
inches in places. This variance in wall thickness is partially
attributable to the large ratio between static wall length and the
large ratio between large and small ring diameter. This gives rise
to the possibility of inadequate thickness at the outside hinges 43
and the possibility of product defects. The greater thickness at
interior hinges 47 may make it more difficult to collapse those
hinges, and may require hinges to have large radii to permit the
walls 41, 42 to fold together when the corrugation is collapsed.
Finally, when the tuck wall 42 swings across the tuck and static
angles to close against static wall 41, it is necessary for the
tuck wall 42 to flex or the smaller ring 44 to compress so that the
tubing can collapse. The greater the difference between smaller
diameter ring 44 and larger diameter ring 45, the greater the
amount of tuck wall 42 flex and inner diameter ring 44 compression
required. If thin walled tubing is used, collapsing can be
irregular with a resulting potato chip type appearance of larger
ring edges instead of closely spaced and vertically aligned ridges.
When utilizing the dimensions of the corrugation described in FIG.
3A, relatively thick walls are required and, in fact, it becomes
impractical to collapse any substantial length of expanded drain
pipe without the use of special devices and it is similarly
difficult to expand any substantial length of pipe. Indeed,
frequently fifteen pounds of force is required to expand a
collapsed corrugation of the pipe of FIG. 3A. In particular, to
overcome the shortcomings of the prior art, the present drain pipe
invention can be advantageously practiced with the corrugation
design illustrated in detail in FIG. 3B.
[0031] Some background about the measurements applied to corrugated
tubing is helpful to their understanding. Corrugated tubing is
manufactured in expanded state, typically on a corrugator. Then the
expanded tubing is collapsed, and some permanent deformation
occurs. If the collapsed tubing is again expanded, it will not
reach its original manufactured length but will typically be about
5%-15% shorter. Subsequent collapsing and expansion does not
significantly alter the tubing's length. Accordingly, all
measurements are taken after the tubing has been collapsed and then
re-expanded after manufacture.
[0032] For the Flex-A-Spout tubing described in FIG. 3A, the
following characteristics are observed:
[0033] Ratio of static angle .beta. to tuck angle .alpha.=127%
[0034] Sum of .alpha. and .beta.=91.degree.
[0035] Collapse ratio=less than 4.5
[0036] Bend radius=6.625 inches
[0037] Ratio of bend radius to maximum diameter=144.3%
[0038] Maximum diameter=4.59 inches
[0039] Minimum diameter=3.664 inches
[0040] Ratio of maximum diameter to minimum diameter=125.27%
[0041] Length of static wall=0.704 inches
[0042] Length of tuck wall=0.504 inches
[0043] Ratio of static wall to tuck wall=139.6%
[0044] FIG. 3B shows expanded corrugations with tuck wall 52 having
a length of 0.38 inches, and connected at hinge 53 to static wall
51 having a length of 0.445 inches. Tuck wall 52 is at an angle of
47.82.degree. with longitudinal axis 18 of drain pipe 10 so that
tuck angle .alpha.=42.18.degree. and static wall 51 is at an angle
of 39.98.degree. with longitudinal axis 18 so that static angle
.beta.=50.02.degree. thereby resulting in a combined angle of
92.2.degree. being formed between tuck wall 52 and static wall 51.
The minor rings 54 have inner diameter of 3.494 inches and the
major rings 55 have inner diameter of 4.09 inches. The shorter wall
lengths and lesser difference between diameters of minor rings 54
and major rings 55 facilitate the collapsing of the corrugation, as
does the thinner wall thickness of about only 0.035 inches that is
required due to the simple hinge 53 and shorter distance between
smaller and larger rings 54, 55, in comparison to the walls of the
embodiment of FIG. 3A. A relatively uniform wall thickness can be
produced on a corrugator. Each corrugation has a width of about
0.667 inches in expanded form. The corrugation of FIG. 3B is shown
in collapsed form in FIGS. 3C and 3D. FIG. 3D is an enlarged view
of one end of the section of FIG. 3C taken along line D-D. FIG. 3D
shows how the tuck wall 52 moved from its original position shown
in phantom through the arc 58 pivoting at hinge 53 so that tuck
wall 52 folds against static wall 51. As the tuck wall 52 proceeded
along arc 58 at the position 59, at which time tuck wall 52 is
substantially aligned with the lateral axis or diameter of a major
ring 55, the greatest pressure is exerted to bend tuck wall 52 and
compress minor ring 54 so that the tuck wall 52 and smaller ring 54
defined by interior hinge 57 could pass through and be collapsed.
In the corrugation design described in FIGS. 3B-3D, expansion of
corrugations manually can be reasonably achieved as a force of only
about ten pounds is required in comparison to the fifteen pounds of
force required for the embodiment described in connection with FIG.
3A. In addition, the bend radius is only 4.5 inches compared to a
bend radius of 6.625 inches of configurations of FIG. 3A.
[0045] Thus for this example of collapsible drain pipe, the
following measurement are applicable:
[0046] Wall thickness=0.035 inches
[0047] Collapse ratio=5.1
[0048] Bend radius=5.5 inches
[0049] Ratio of bend radius to maximum diameter=1.34
[0050] Maximum diameter=4.09 inches
[0051] Minimum diameter=3.494 inches
[0052] Ratio of maximum diameter to minimum diameter=117%
[0053] Length of static wall=0.445 inches
[0054] Length of tuck wall=0.380 inches
[0055] Ratio of static wall to tuck wall length=117.1%
In particular, a number of desirable characteristics are
demonstrated, which provide advantages individually and in
combination. For a collapsible drain pipe, it is desirable that the
wall thickness be less than 0.04 inches. It is also desirable that
the collapse ratio of the corrugated sections be at least about 5.
Of particular significance for packaging, and precise deployment,
it is desirable to achieve a ratio of bend radius to maximum
diameter of less than 1.5, and preferably less than 1.40 or 1.35.
The illustrated embodiment achieves a ratio of static wall to tuck
wall length of less than 1.2 at about 117.1%. The ratio of the
length of the static wall to the tuck wall is preferably less than
1.35, 1.30, 1.25 or 1.20. The sum of the angles .alpha. and .beta.
should be less than 110.degree. and preferably less than
100.degree.. Tuck angle .alpha. should be at least 3.degree. less
than static angle .beta., and the ratio of .beta. to .alpha. should
be less than 1.25 and preferably less than 1.20. The force required
to expand a corrugation should be no more than about twelve or even
ten pounds of force. The ratio of the maximum diameter to minimum
diameter and the ratio of static wall to tuck wall length can also
be optimized to be similar, within about 10% of one another.
[0056] FIG. 3E illustrates another prior art corrugation design 60
with static wall 61 at 0.138 inches, hinge 63 and tuck wall having
a first portion 62a and a second portion 62b at slight angle. This
allows the total tuck angle .alpha. of 48.65.degree. between second
tuck wall portion 62b and the longitudinal axis 18 of pipe 10 to be
greater and the reach obtained between the interior hinges 67 to be
greater than would otherwise be allowed by the hinge 63. In this
design, the static wall has a length of 0.195 inches and a static
angle of 51.51.degree., a maximum diameter of 1.326 inches and a
minimum diameter of 1.064 inches. However, this corrugation design
has been used only with small diameter tubing, on the order of one
inch or less, with correspondingly reduced wall thicknesses, on the
order of 0.020 inches. When used on larger diameter tubing, there
appears to be no practical effect in the collapsibility or
compression ratio of the tubing, as compared to that achieved by a
straight tuck wall extending to the same end point. Small diameter
tubing on the order of less than two inches in diameter is not
fairly comparable with the three to five inch diameter tubing used
in drain pipes because the force to collapse the smaller thin
walled tubing is much less, even if the smaller tubing is not
optimally designed, and storage concerns are not as severely
implicated.
[0057] The other principal prior art gutter spout design pipe
configuration is of a generally rectangular shape as shown in FIGS.
3F and 3G. This tubing 70 has a tuck angle .alpha. of 43.9.degree.
and a static angle .beta. of 50.0 for a combined angle of
93.9.degree. and a ratio of .beta. to .alpha. of almost 114%. The
tuck wall 72 has a length of 0.320 and the static wall 71a length
of 0.445 for a ratio of static wall to tuck wall of over 139%. Each
corrugation has a width of about 0.645 inches in expanded form.
[0058] Due to the rectangular shape, this pipe 70 has different
ratios and performs differently along its major (vertical) and
minor (horizontal) axes. Specifically, along the major axis, the
maximum diameter 75 is 4.978 inches and the minor diameter 74 is
4.382 so that the ratio of maximum to minor diameter is 113.6%. The
bend radius in this direction is 8.5 inches, or a ratio of over
170% to the maximum diameter. In the direction of the minor axis,
the minimum diameter 78 is 3.387 inches and the maximum diameter 79
is 3.923 inches so that the ratio of maximum to minor diameter is
nearly 118%. The bend radius is 6.25 inches so that the ratio of
bend radius to maximum diameter is 159.3%.
[0059] In order to utilize the drain pipe of the invention,
typically a trench is excavated to a desired depth, including the
thickness of the pipe plus the thickness of bedding material to
place beneath the pipe and the haunching and backfill to be placed
above the pipe. Because the pipe with corrugation according to
FIGS. 3B-3D can bend around a 4.5 inch radius, it is possible to
plot a very direct route for excavating the trench. The pipe may
also be provided with holes in the side wall so that it may receive
drainage through the side wall, especially the upper side wall.
Although if used in septic applications, the pipe may allow
drainage out through the side wall, especially the lower side
wall.
[0060] After the trench is prepared at appropriate grade to allow
for drainage, and large rocks are removed from the bottom or sides
of the trench, then bedding material to provide firm but not hard
support for the drain pipe is placed in the trench. If the
unexcavated bottom of the trench is used as bedding, it should be
relatively flat and free of large rocks or obstructions. Then, the
drain pipe is extended to its full length by bending it to the
right and the left while pulling. Generally, no more than about ten
pounds of force is required. If the length is longer than one pipe
section, then male 30 and female 20 cuffs are snapped together from
adjacent pipe sections. The pipe is laid along the side of the
trench and the pipe is bent by collapsing one side as necessary to
form the desired shape. The excess pipe may be trimmed with a knife
or other cutting instrument, or unneeded length may be left in
collapsed form, and the pipe dropped into place in the trench. Then
haunching is preferably added on either side of the pipe and
covering the pipe. Then layers of backfill are added and compacted
in layers until the drain pipe is covered by the desired depth.
[0061] A particular advantage of the bend radius achieved by
expandable flexible drain pipe is illustrated in FIGS. 4A-4C. The
drain pipe may be oriented lengthwise in compressed form and bent
in half to form a first bend 87 placing the female cuff 20 and male
cuff 30 adjacent to one another. Then the bent pipe may be bent
again to form second and third bends 88, 89 resulting in the cuffs
20, 30 being adjacent to the first bend 87. This results in the
drain pipe 10 being configured as four lengths of compressed tubing
that may be encircled by a four panel box 70 advantageously having
a top panel 71 with a grip such as handhold 72. The open front end
74 and open rear end 75 of the four panel box enables the drain
pipe 10 to be easily inspected by consumers. Fold-in corners 76 of
the box provide some rigidity to the structure and the resulting
generally rectangular assembly is easily stacked on retailer
shelves, in carts and in consumer vehicles for transport. To
achieve this compact packaging form, it is desirable that the drain
pipe have a ratio of bend radius to major diameter of no more than
1.4, and desirable results are obtained when this ratio is less
than 1.35, 1.30, 1.25, 1.20 and 1.15. When packaged, the length of
each compressed segment of tubing is preferably no more than 24
inches to optimize palletizing of the packaged tubing for
shipment.
[0062] Alternative packaging configurations are also possible such
as rectangular box 80 having a top panel 81 and handle 82, side
panel 83 with window 84 permitting consumer inspection of drain
pipe 10. Typically, the drain pipe is again folded with first,
second and third folds 87, 88, 89 as shown in FIGS. 4A and 5 and
placed in box 80 where it is conveniently displayed for sale and
transport by consumers. An alternative tall panel package 90 with
handle 92 and front panel 93 is also possible. The tall package 90
has open front end 94 and open back end 95 to readily permit
consumer inspection of drain pipe 10. The compressed drain pipe
extends from male cuff 30 through first collapsed section to first
bend 97 through a second compressed section to second bend 98 and
third compressed section to third bend 99 and a fourth compressed
section to female cuff 20. In this instance, the four compressed
sections of drain pipe 10 are vertically stacked to present a
different product configuration that is still easily displayed by
retailers and easily carried and transported by consumers. An
extremely tight bend radius is not as critical in this form of
packaging, however, it is still preferred that the ratio of bend
radius to maximum diameter be no more than 1.5.
[0063] FIG. 5 demonstrates a method of securing the folded drain
pipe 10 where the collapsed drain pipe is bent in the middle to
bring male cuff 30 and female cuff 20 together thereby forming
first bend 87. In order to make this bend, tooling points such as
uncollapsible rings 19 are positioned at either side of the
midpoint during manufacture. After being manufactured in expanded
state, the corrugated drain pipe is collapsed, however, the
uncollapsible rings 19 do not collapse, and may be easily grasped
manually or by tooling to accurately make the middle bend in the
drain pipe. Then the cuffs 20, 30 are folded over into proximity to
first bend 87 thereby creating second and third bends 88, 89, and
wraps 38 are placed about the four compressed sections of drain
pipe 10 thereby holding the entire folded product in place. Similar
tooling points 19 are preferably placed on either side of the
second and third bends. It is to be understood that packaging of
the drain pipe is not required and it might be advantageously sold
in a straight compressed six foot length, or with only a single
bend into two compressed sections.
[0064] All publications, patents, and patent documents are
incorporated by reference herein as though individually
incorporated by reference. Although preferred embodiments of the
present invention have been disclosed in detail herein, it will be
understood that various substitutions and modifications may be made
to the disclosed embodiment described herein without departing from
the scope and spirit of the present invention as recited in the
appended claims.
* * * * *