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.

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  4 B. 
       
    
    
     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°, 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  2 B, 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° 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&#39; drain pipe fittings. 
         [0029]      FIGS. 3A-3G  illustrate a variety of corrugation styles utilized in collapsible tubing. FIGS.  3 A and  3 E-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 α, and β, 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° with the longitudinal axis  18  of the pipe  10  so that the tuck angle α is 40.07°. The static side is at an angle of 39.1° with the longitudinal axis  18  so that the static angle β is 50.9°. The sum of α and β is about 91°. 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&#39;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 β to tuck angle α=127% 
         [0034]    Sum of α and β=91° 
         [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° with longitudinal axis  18  of drain pipe  10  so that tuck angle α=42.18° and static wall  51  is at an angle of 39.98° with longitudinal axis  18  so that static angle β=50.02° thereby resulting in a combined angle of 92.2° 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% 
         [0000]    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 α and β should be less than 110° and preferably less than 100°. Tuck angle α should be at least 3° less than static angle β, and the ratio of β to α 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  62   a  and a second portion  62   b  at slight angle. This allows the total tuck angle α of 48.65° between second tuck wall portion  62   b  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°, 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 α of 43.9° and a static angle β of 50.0 for a combined angle of 93.9° and a ratio of β to α of almost 114%. The tuck wall  72  has a length of 0.320 and the static wall  71   a  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.