Abstract:
A fluid conduit includes a flexible member having a tubular wall for conveying a fluid and a circumferential structural member positioned adjacent to the tubular wall. The structural member is disposed about a central axis of the conduit so as to form a plurality of spaced segments along the wall. The segments are spaced apart relative to each other to define a gap therebetween. The gap is sized to be closed by contact between adjacent segments upon a predetermined flexure of the flexible member. A method of forming the fluid conduit includes forming a flexible member with a tubular wall and forming a groove about a central axis of the conduit in a portion of the tubular wall. The groove is formed by removing material from the tubular wall or compressing material on the tubular wall.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/785,261, filed Mar. 14, 2013, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to fluid conduits and, more particularly, to flexible hoses. 
       BACKGROUND 
       [0003]    Flexible hoses are widely utilized in a wide variety of industrial, household, and commercial applications. One commercial application for hoses are garden or water hoses for household or industrial use. For instance, the hoses are used for watering grass, trees, shrubs, flowers, vegetable plants, vines, and other types of vegetation, cleaning houses, buildings, boats, equipment, vehicles, animals, or transfer between a fluid source and an appliance. For example, the appliance can be a wash stand, a faucet or the like for feeding cold or hot water. Another commercial application for hoses are automotive hose for fuel delivery, gasoline, and other petroleum-based products. Another application for hoses are vacuum cleaner hoses for household or commercial applications. For instance, the hoses are used with vacuum cleaners, power tools, or other devices for collecting debris or dispensing air. Fluids, such as beverages, fuels, liquid chemicals, fluid food products, gases and air are also frequently delivered from one location to another through a flexible hose. 
         [0004]    Flexible hoses have been manufactured for decades out of polymeric materials such as natural rubbers, synthetic rubbers, thermoplastic elastomers, and plasticized thermoplastic materials. Conventional flexible hoses commonly have a layered construction that includes an inner tubular conduit, a spiraled, braided, or knitted reinforcement wrapped about the tubular conduit, and an outer cover. 
         [0005]    Kinking and collapsing are problems that are often associated with flexible hoses. Kinking occurs, for example, when the hose is doubled over or twisted. A consequence of kinking is that the flow of fluid through the hose is either severely restricted or completely blocked. Kinking becomes a nuisance and causes a user undue burden to locate and relieve the kinked portion of the hose. 
         [0006]    There have been previous attempts to make hoses more resistant to kink, collapse, crush, and/or burst by incorporating a spiral or helical reinforcement strip into the outer tubular layer of the hose. This construction, however, has often made these reinforced hoses unduly stiff because the embedded helix lacks the ability to flex freely. This construction in some cases has often required thicker and more rigid inner tubular layers. What is needed, therefore, is a spiral reinforced fluid conduit in which the spiral reinforcement is readily customizable to suit the different performance needs of its users. 
       SUMMARY 
       [0007]    A fluid conduit in one embodiment includes a flexible member having a tubular wall configured to convey a fluid, the tubular wall defining a central axis extending through the flexible member, and a circumferential structural member located adjacent to the tubular wall, the structural member disposed about the central axis so as to form a plurality of segments along the tubular wall, the segments being spaced apart relative to each other to define a gap therebetween, the gap sized to be closed by contact between adjacent segments upon a predetermined flexure of the flexible member. 
         [0008]    A method of forming a fluid conduit in one embodiment includes forming a flexible member with a tubular wall, the tubular wall defining a central axis extending through the flexible member, and forming a circumferential structural member adjacent to the tubular wall, the structural member disposed about the central axis so as to form a plurality of segments along the tubular wall, the segments being spaced apart relative to each other to define a gap therebetween, the gap sized to be closed by contact between adjacent segments upon a predetermined flexure of the flexible member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a section cut through a portion of a flexible fluid conduit having a structural layer formed in accordance with the present disclosure; 
           [0010]      FIG. 2  is a perspective view of the structural layer of  FIG. 1 ; 
           [0011]      FIG. 3  is a side plan view of the structural layer of  FIG. 1 ; 
           [0012]      FIG. 4  is an auxiliary view of a one-half revolution of a strip forming the structural layer; 
           [0013]      FIG. 5  is a section cut through the strip of  FIG. 4  along line A-A; 
           [0014]      FIGS. 6-8  are section cuts through three embodiments of a conduit having the structural layer of  FIG. 1  positioned differently in each embodiment; 
           [0015]      FIGS. 9-12  are front plan views illustrating alternative methods to alter an intermediate layer of the conduit for integration with the structural member; 
           [0016]      FIGS. 13-17  are section cuts through the conduit of  FIG. 1  depicting the interaction between adjacent segments of the structural layer when the conduit is bent; 
           [0017]      FIGS. 18-22  are section cuts through the conduit of  FIG. 1  illustrating how dimensional changes to the features of the structural layer impact the flexibility of the conduit when the conduit of is bent along its central axis; 
           [0018]      FIGS. 23-24  are section cuts through the conduit of  FIG. 1  illustrating how the flexibility and compressibility of the intermediate layers and the segments of the structural layer effect the flexibility of the conduit; 
           [0019]      FIG. 26  is a section cut through a portion of the conduit of  FIG. 8  having a structural layer configured to move relative to the intermediate layers; and 
           [0020]      FIGS. 27-28  are section cuts through a portion of the conduit having a portion of an intermediate layer embedded between the segments of the structural layer. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the disclosure is thereby intended. It is further understood that the disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one skilled in the art to which this disclosure pertains. 
         [0022]      FIG. 1  shows a straight portion of flexible fluid conduit  100  sectioned along its central axis  102 . The conduit  100  includes an outer liner  106  and inner liner  104  that forms a flow path through the conduit  100 . In the embodiment shown, the conduit  100  further includes a structural layer  108  positioned between the inner and outer liners  104 ,  106 . The structural layer  108 , as discussed in more detail below, is configured to prevent the restriction of fluid flow along the flow path due to bending or kinking of the conduit  100 . 
         [0023]    As best shown in  FIGS. 2 and 3 , the structural layer  108  is embodied as a strip of semi-flexible material that is positioned helically about the central axis  102 . For purposes of this disclosure, the central axis  102  of the structural layer  108  and the central axis  102  of the conduit  100  are coincident, and any further reference to “central axis” refers to both axes. Each revolution of the strip has a gap  109  formed therebetween. In other embodiments, the gap  109  is vacuum or air filled. The consecutive gaps along the length of the structural layer  108  enable the structural layer  108  to flex and to extend and compress axially. 
         [0024]    In some embodiments, the structural layer  108  is formed by wrapping the strip around a form. In other embodiments, the structural layer  108  is formed by extruding a tube and then spiral shaping the tube to form helical grooves about the central axis  102 . The spiral cut in some embodiments is made entirely through the wall of the tube and in other embodiments is made partially through the wall of the tube. 
         [0025]    When viewed along the section depicted in  FIG. 1 , the spacing between each helical revolution of the strip forms a series of spaced segments  110  above the central axis  102  and a series of spaced segments  110  below the central axis  102 . As discussed in more detail below, it is the interaction between the spaced adjacent segments in the series of segments  110  that enables the structural layer  108  to prevent restrictions in the flow path when the conduit  100  is subjected to a collapsing or bending force. 
         [0026]      FIG. 4  depicts an auxiliary view of a one-half revolution  112  of the strip when the strip is viewed from the arrow  114  of  FIG. 3 .  FIG. 5  shows a cross section of the one-half revolution of the strip of  FIG. 4  taken along line A-A with the section line oriented perpendicular to the helical path of the strip. In the embodiment shown, the strip has a rectangular cross section with a constant width W and a constant height H. In other embodiments, however, the width W and the height H of the cross section can vary over the length of the structural layer  108 . 
         [0027]      FIGS. 6-8  show three embodiments  116 ,  117 ,  118  of a conduit with the structural layer  108  at a different position on the conduit in each embodiment. The conduit of each of the embodiments includes an inner liner  104 , a woven sleeve  120 , a foamed liner  122 , and an outer liner  106  each radially positioned from inside to outside about the central axis  102 . In the embodiments shown, the woven sleeve  120  is depicted as a one-dimensional line between adjacent conduit layers. The structural layer  108  in each embodiment is at a different position within the conduit. For example,  FIG. 6  shows the structural layer  108  positioned on the exterior of the conduit  116  adjacent to the outer liner  106 .  FIG. 7  shows the structural layer  108  of the conduit  117  positioned between the foamed liner  122  and the outer liner  106 .  FIG. 8  shows the structural layer  108  positioned within the interior of the conduit  118  adjacent to the flow path on the inside and the inner liner  104  on the outside. The embodiments of  FIGS. 6-8  show the conduit as comprising five layers with the structural layer  108  positioned at three different locations within these layers. In other embodiments, the conduit can include lesser or greater numbers of layers with the structural layer  108  positioned between any of the provided layers. 
         [0028]    The structural layer  108  in some embodiments is free to move or float rotationally around and/or axially along the central axis  102  of the conduit regardless of its position within the conduit. In other embodiments, the structural layer  108  is bonded to one or more adjacent layers of the conduit to restrict its relative movement about or along the central axis  102 . The bonding of the structural layer  108  in these embodiments can be accomplished by any practical method. In one embodiment, an adhesive is used to secure the structural layer  108  to one or more of the adjacent conduit layers. 
         [0029]    In some embodiments in which movement of the structural layer  108  is at least partially restricted, the structural layer  108  and at least one adjacent layer are integrated into a single layer. The integration of the structural layer  108  and the at least one adjacent layer can be accomplished as part of the extrusion process that forms the adjacent layer or by altering the adjacent layer after the extrusion process. 
         [0030]      FIGS. 9-12  schematically illustrate methods to alter an adjacent layer  124  for integration with the structural layer  108 .  FIG. 9 , for example, depicts the use of a tool  125  to press form or cut a helical groove  126  about the extruded adjacent layer  124  while the layer  124  is still soft. In some embodiments, the tool  125  is a forming tool rotated about the adjacent layer  124  in the direction of arrow  127  to form the helical groove  126  for the structural layer  108 . In other embodiments, the forming tool  125  is fixed and the adjacent layer  124  is rotated in the direction of arrow  128  to form the groove  126 . In other embodiments, the tool  125  of  FIG. 9  is a rotating cutting tool used to mechanically remove material from the adjacent layer  124  to form the groove  126 . In other embodiments, the tool  125  of  FIG. 9  is a rolling tool used on the adjacent layer  124  to relieve or remove material from the adjacent layer  124 , depending on the application, to create the void  126 . 
         [0031]    In some embodiments, such as the embodiment shown in  FIG. 10 , a fixed cutting tool  129  is used and the adjacent layer  124  is rotated about the fixed cutting tool  129  to form the structure  126 . The tool can be, for example, a rotating padding tool, a blade or scribing tool ( FIG. 10 ), or the like, or any combination thereof.  FIG. 11  depicts the use of a tool  130 , such as a laser, to thermally remove material from the adjacent layer  124  to form the groove  126 . In other embodiments, the use of the laser  130  can modify a portion of the material from the adjacent layer  124  to release the structural layer  108 . In some embodiments, the tool  130  forms the helical groove  128  by a non-thermal, non-contact method. The tool  130  in these embodiments directs an effect such as a frequency pulse, air wave, ripple effects or the like at the adjacent layer  124  to form the void or groove  126 .  FIG. 12  illustrates the use of a forming feature  131  protruding from the ring portion  132  of an extrusion device  133  to form the groove  126 . In this embodiment, as the adjacent layer  124  is moved through the extrusion device  133 , the ring portion  132  rotates about the adjacent layer  124  and the forming feature  131  forms the helical groove  126 . Although specific tools and methods have been described with reference to  FIGS. 9-12 , any tool or method can be used to form the groove  126  in the adjacent layer during or after extrusion. 
         [0032]      FIGS. 13-17  schematically depict the interaction between adjacent segments  110  of the structural layer  108  when the conduit  100  of  FIG. 1  is bent along its central axis  102 .  FIG. 13  shows the conduit  100  of  FIG. 1  having a downward bend along its central axis  102 . In the embodiment of  FIG. 13 , the downward bend of the conduit  100  produces an outer bend  134  along the conduit  100  above the central axis  102  and an inner bend  136  along the conduit  100  below the central axis  102 . 
         [0033]    For purposes of this disclosure, the relative directions “down”, “downward”, or “downwardly” refer to a direction pointing toward the bottom of the drawing sheet and the relative directions “up”, “upward”, or “upwardly” refer to a direction pointing toward the top of the drawing sheet. Similarly, the terms “bottom” or “below” refer to relative positions closer to the bottom of the drawing sheet and the terms “top” or “above” refer to relative positions closer to the top of the drawing sheet. 
         [0034]    The following subscripts are used in conjunction with the letter X to denote the various segment-to-segment gap distances shown in the figures: (s)=straight conduit, (d)=downward bent conduit, (o)=outer bend position, (i)=inner bend position, (t)=tip gap between adjacent segments, and (b)=base gap between adjacent segments. For example, the gap distance X dot  refers to the gap measured on a downward bent conduit (the subscript “d”) at the outer bend position (the subscript “o”) at the tip of the segments (the subscript “t”). 
         [0035]      FIG. 14  shows two adjacent segments  110  positioned above the inner liner  104  at the approximate position of the outer bend  134  before the conduit  100  is bent. In the straight conduit of  FIG. 14 , the facing sides  138  of the adjacent segments  110  are parallel with respect to each other. Accordingly, the gap between the segments  110  at the base of the segments  110  or the base gap X sob  and the gap between the segments  110  at the tip of the segments  110  or the tip gap X sot  are equal. In other words, the base gap X sob  and the tip gap X sot  can be collectively referred to as the straight gap X so  of the straight conduit at the position of the outer bend  134 . When the conduit  100  is bent downward at the outer bend  134  as depicted in  FIGS. 13 and 15 , the base gap of the bent conduit X dob  is approximately equal to or greater than the straight gap of the straight conduit X so . The tip gap of the bent conduit X dot , however, is typically greater than the straight gap of the straight conduit X so  since the adjacent segments  110  rotate away from each other as the inner liner  104  bends downward. 
         [0036]      FIG. 16  shows two adjacent segments  110  positioned below the inner liner  104  at the approximate position of the inner bend  136  before the conduit  100  is bent. In the straight conduit of  FIG. 16 , the facing sides of the adjacent segments  110  are parallel with respect to each other. Accordingly, the gap between the segments  110  at the base of the segments  110  X sib  and the gap between the segments  110  at the tip of the segments X sit  are equal. In other words, the base gap X sib  and the tip gap X sit  can be collectively referred to as the straight gap X si  of the straight conduit at the position of the inner bend  136 . 
         [0037]    When the conduit  100  is bent downward at the inner bend  136  as depicted in  FIGS. 13 and 17 , the base gap of the bent conduit X dib  is approximately equal to or less than the straight gap of the straight conduit X si . The tip gap of the bent conduit X dit , however, can range from slightly less than the straight gap of the straight conduit X si  to zero. In other words, after a predefined amount of bending, the tips of the segments  110  at the inner bend  136  contact each other and provide a positive stop to prevent further bending of the conduit  100  at positions adjacent to the contacting segments  110 . The segment-to-segment contact between each of the adjacent segments in the series of segments  110  prevents the conduit  100  from collapsing into the flow path and substantially restricting the fluid flow therethrough. 
         [0038]      FIG. 18  shows two adjacent segments  110  positioned above the inner liner  104  at an inner bend  136  of the conduit  100  after the conduit  100  of  FIG. 1  has been bent upwardly (not shown). The adjacent segments  110  have a height H, a width W, a base gap X, and form a contact angle A having its vertex at the contact point of the segments  110 . The maximum contact angle A formed between each of the adjacent segments in the series of segments  110  is one of a number of factors that determines the relative amount of bend of the conduit  100  over its length. 
         [0039]    As shown by comparing  FIGS. 18 and 19 , reducing the base gap between the adjacent segments  110  from X to X′ while holding constant the height H c  and the width W c  of the segments  110  reduces the contact angle from A to A′ and, therefore, reduces the overall amount of bend in the conduit  100 . The contact angle A′ is reduced because the reduction in the base gap between the adjacent segments  110  moves the effective pivot points of the segments  110  closer together as the conduit  100  bends in the upward direction. Accordingly, the segments  110  rotate less before the tips of the segments  110  contact each other. If the base gap X between the adjacent segments  110  of  FIG. 19  is increased, the contact angle A similarly increases, allowing more overall bend in the conduit  100  before the tips of the segments  110  contact each other. 
         [0040]    As shown by comparing  FIGS. 18  and  FIG. 20 , reducing the height of the adjacent segments  110  from H to H′ while holding constant the base gap X c  between the segments  110  and the width W c  of the segments  110  increases the contact angle from A to A″ and, therefore, increases the overall amount of bend in the conduit  100 . The contact angle A″ is increased because the reduction in the height of the adjacent segments  110  allows the segments  110  to rotate further about their effective pivot points before the tips of the segments  110  contact each other. If the height H of the adjacent segments  110  of  FIG. 20  is increased, the contact angle A decreases, allowing less overall bend in the conduit  100  before the tips of the segments  110  contact each other. 
         [0041]    As explained with reference to  FIGS. 21 and 22 , reducing the width of each of the segments  110  from W ( FIG. 21 ) to W′ ( FIG. 22 ) while holding constant the base gap X c  between the segments  110  and the height H c  of the segments  110  results in more flex regions  140  between the segments  110  for the same overall length of conduit  100 . Increasing the number of flex regions along the length of the conduit increases the overall flexibility of the conduit because the cumulative length of the conduit capable of flexing increases with each added flex region. 
         [0042]    As shown in  FIGS. 23 and 24 , a reduction in the flexibility of the liner  104  can reduce the overall flexibility of the conduit  100 . In a straight conduit, the base gaps between the segments  110  in each of  FIGS. 23 and 24  are equal. The highly flexible inner liner  104  of  FIG. 23  allows the maximum distance between the effective pivot points of the segments  110  in the bent conduit. In contrast, the more rigid inner liner  104 ′ of  FIG. 24  reduces the distance between the effective pivot points in the segments  110  in the bent conduit. In particular, a line  142  connecting the effective pivot points of the segments  110  of  FIG. 23  falls along the path of the inner liner  104 , indicating that the line  142  represents the maximum distance between the effective pivots points. In contrast, a line  144  connecting the effective pivot points of the segments  110  of  FIG. 24  does not fall along the path of the inner liner  104 ′ due to the reduced flexibility of the inner liner  104 ′. 
         [0043]      FIG. 25  illustrates the effect that the compressibility of the strip material has on the contact angle between the adjacent segments  110 . In the embodiment shown, the strip material at the contact point  146  between the two adjacent segments  110  is slightly deformed due to the compression of the material. For purposes of this disclosure, the term “non-deformed contact angle” refers to the angle formed when adjacent segments first make contact at the contact angle  146 , but before either of the segments begins to deform. The term “fully-deformed contact angle” refers to the angle formed after adjacent segments have made contact at the contact point  146  and after both of the segments are fully deformed. As the segments  110  become more compressible, especially at their tip, the difference between the non-deformed contact angle and the fully-deformed contact angle increases between the adjacent segments  110 , resulting in more overall flexibility in the conduit. The converse is also true. That is, as the segments  110  become less compressible, the difference between the non-deformed contact angle and the fully-deformed contact angle decreases between the adjacent segments  110 , resulting in reduced overall flexibility in the conduit. 
         [0044]    Although the structural layer  108  has been primarily depicted in the figures as bonded to or integrated with one or more of the layers of the conduit  100 , the structural layer  108  can also be provided as a free floating structural layer  208  over the exterior or within the interior of the conduit. For example,  FIG. 26  shows a section of the conduit  118  of  FIG. 8  taken along its central axis  102 . In this embodiment, the conduit  118 ′ is bent downwardly along its central axis  102 . The structural layer  208  is positioned radially inside the inner liner  104  and, because the structural layer  208  is not bonded to the inner liner  104 , it is free to move or float relative to the inner liner  104 . The segments  210  of the free floating structural layer  208  prevent flow path restriction in a manner similar to that of the segments  110  of the bonded structural layer  108 , but the segments  210  provide the conduit  118 ′ with a greater range of bending motion. 
         [0045]      FIGS. 27 and 28  illustrate the effect that integration of the structural layer  108  with another layer has on the flexibility of the conduit  100 .  FIG. 27  depicts two adjacent segments  110  in a straight section of the conduit  100 . The segments  110  are adjacent to the inner liner  104  and integrated with the outer liner  206 . The gap between the adjacent segments  110  is occupied by the material of the outer liner  206 .  FIG. 28  shows the two adjacent segments  110  after the conduit  100  of  FIG. 27  has been upwardly bent. In this embodiment, as the segments  110  come together due to the bending of the conduit  100 , the portion  210  of the outer liner  206  between the segments  110  is compressed. The density of the outer liner material, therefore, determines how close the segments  110  can get to each other. Bending of the conduit  100  in the opposite direction causes the outer liner material to stretch between the segments  110 . 
         [0046]    The spiral reinforced fluid conduit of the present disclosure is suitable for automotive, household, commercial, aerospace, medical, and industrial uses. The plurality of spiral or helical reinforcement members enable the structural layer to flex and to extend and compress axially. 
         [0047]    While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the disclosure are desired to be protected.