Abstract:
A flexible bellows used in a pipe coupling includes composite convolutions having integral extensions forming one or both of an outer shield or inner liner to enhance performance of the coupling. Embodiments incorporate dampers, hangers and convolution modifications. Various embodiments are disclosed.

Description:
RELATED APPLICATION 
     Applicant claims the benefit of the filing date of U.S. provisional patent application Ser. No. 61/052,662 filed May 13, 2008, entitled, “FLEXIBLE ELEMENT WITH INTEGRAL OUTER SHIELD AND/OR INNER LINER”, the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to flexible piping elements and more specifically to couplings for pipes, particularly useful in, but not limited to, couplings for exhaust pipes from internal combustion engines. 
     BACKGROUND OF THE INVENTION 
     Couplings for pipes, particularly exhaust pipes, have been known. Prior couplings including bellows with separate inner liners and/or separate outer shields have been used in exhaust pipe environments. 
     Such environments are harsh. Heat produces or influences thermal changes in such pipes and couplings. Noise, vibration and harshness (hereinafter NVH) are produced by the environment of the exhaust from internal combustion engines must be handled. Motion, in the form of bending, must be accommodated as well, as pressure changes. Aspects of convection cooing affect such pipes and couplings. Mounting points for support and suspension of such couplings vary between applications but many prior couplings are not generally flexible in the location or placement of mounts. 
     Known coupling apparatus deals with such concerns in a variety of ways, leaving room for a great deal of improvement. Such known apparatus typically requires a separate inner liner to limit compression of the bellows, to reduce the impact of the flowing medium to the bellows, and to reduce turbulence and/or an outer shield to limit extension, to protect the bellows from a harsh environment and to add NVH damping properties. These items, i.e. liner and/or shield are usually added at considerable cost and complexity. Mounting points and hardware require a large variety of designs, adapters and the like. 
     In the past, bellows have been edge welded. But edge welded bellows do not have integral liners or outer shields and lack flexibility in provisions for mounting. Hydroformed, elastomeric formed, or mechanically formed bellows have been proposed. But these are limited by the material specifications and forming processes and they require separate outer shields and/or inner liners. The same material limitations evident on conventional bellows, also constrains one of its main purposes, that being durability under flexibility. Molded bellows have the same concerns as above. Additional disadvantage of a conventional bellows as described above is the complexity required to mount/hinge support conventional bellows other than on the end of the bellows. 
     Accordingly, it is desired to uniquely integrate all components: bellows, outer shield, and/or inner liner, mount/hinge) together to overcome and improve the features in the prior known couplings. 
     It is also desired to provide considerable flexibility in the bellows&#39; convolutions so as to better optimize the overall functionality, particularly in the environmental conditions noted above. 
     SUMMARY OF THE INVENTION 
     To these ends, the invention in preferred embodiments includes a flexible element which is the basis for an elastic connection of pipes and which compensates for thermal influences, pressure changes, motion (such as bending), noise, vibration and harshness (NVH), or provides convection cooling and other such benefits. 
     While existing art contains flexible gas tight elements that consist of a bellows provided with a separate inner liner, and/or a separate outer shield, this invention contemplates a bellows having an integral outer shield and/or an integral inner liner. Several components can be added to this bellows with integral outer shield and/or integral inner liner to achieve additional functionality in a unique structure. The invention can be made with a variety of materials and with any number of homogeneous or variant plies thicknesses of the materials. 
     The integral construction noted provides a gas tight but flexible connection that is capable of compensating, and performing the benefits of, compensating thermal influences, pressure changes, motion (such as bending), noise vibration and harshness (NVH), and other such environmental conditions. 
     Such a new concept improves piping system life, NVH compensation assembly ease, available cooling surface and provides flexibility in mounting/hinging points. The invention does this at a lower overall cost by integrating the inner liner and/or the outer shield with the bellows. 
     Accordingly, the present invention provides a superior and lower cost product with integrated additional functionality like mounting/hinging points. 
     In more detail, the integral bellows construction of this invention is achieved by adhering (by welding, chemical bonding, or other such method of adhering) two formed (by stamping, molding, cutting or other such forming method) discs together to form a convolution of the bellows. The overlap at the two adhered ends is used to form the outer shield and/or inner liner. Any number of convolutions can be adhered to form a larger and more flexible bellows with an integral outer shield and/or integral inner liner. The configuration of the bellows can take into consideration the number of plies thickness, the various end configuration, the various materials and thicknesses, the overlap geometry for the outer shield or inner liner, and other such variations. The overlap areas (at the ends of the discs) can be modified to add additional features such as a rod or cable to limit extension or provide mounting. Damping material can be added between the convolutions and trapped by the end features to create a bellows assembly with damping properties. 
     These and other objectives and advantages will be more readily apparent from the following written description of the preferred embodiments and from the drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of one embodiment of the invention with the bellows defining an integral outer shield and integral inner liner; 
         FIG. 1A  is a cross-section view of the invention of  FIG. 1 , along lines  1 A- 1 A of  FIG. 1  and showing two convolutions of a multiple convolution bellows with the inner liner and outer shield integrated with the bellows; 
         FIG. 1B  is a cross-section view similar to  FIG. 1A , but of an alternate embodiment of the invention with an alternative bellows disc concept, minimizing the overlap at the ends; 
         FIG. 1C  is a cross-section view similar to  FIG. 1A , but of another alternate embodiment of the invention with only an integral outer shield; 
         FIG. 1D  is a cross-section view similar to  FIG. 1A , but of another alternate embodiment of the invention with only an integral inner liner; 
         FIG. 1E  is a cross-section illustrative view similar to  FIG. 1A  but of one convolution of a bellows with an alternative overlap end to simplify the forming process after the ends are joined; 
         FIG. 1F  is a cross-section view similar to  FIG. 1A  but illustrating an alternate embodiment of the invention with integral outer shields and integral inner liner and showing three convolutions of varied height to facilitate the required movement of the bellows; 
         FIG. 1G  is a cross-section view similar to  FIG. 1A  but illustrating an alternate embodiment of the invention with both an integral outer shield and an inner liner, the geometry of the inner liner can be modified to optimize the flow and NVH characteristics of the medium in the piping system, or in the case of the outer shield, the shielding properties; 
         FIG. 2  is an isometric view of a bellows in an alternate embodiment of the invention with an integral inner liner and integral outer shield where the outer shield has a cable or rod threaded through holes in the outer shield to provide a bellows&#39; extension stop; 
         FIG. 3  is an isometric view of a bellows in an alternate embodiment of the invention with the integral inner liner and integral outer shield with a damping medium added between the convolutions and fixed by the outer shield to add damping properties to the bellows; 
         FIG. 3A  is a cross-section along lines  3 A- 3 A of a bellows of  FIG. 3  with the integral inner liner and integral outer shield and a damping medium is added between the convolutions and fixed by the outer shield to add damping properties of the bellows; 
         FIG. 4  is an isometric view of a bellows in an alternate embodiment of the invention with an integral mounting/hinge support, where one of the convolutions (any across the bellows can be selected depending on the application) has a special inner and outer disc defining the mounting feature; 
         FIG. 4A  is a cross-section of a bellows of  FIG. 4  with an integral mounting/hinge support and showing the invention before bending of the integral inner liner and integral outer shield feature at  FIG. 1A , excepting the mounting feature convolution; 
         FIG. 5  is a perspective drawing illustrating the addition of end caps to an exemplary bellows unit; 
         FIG. 6  is a cross-sectional view of a portion of a bellows with end caps as in  FIG. 5 ; 
         FIG. 7  is a cross-sectional view similar to  FIG. 6  but of a portion of an alternate bellows with end cap; 
         FIG. 8  is a cross-sectional view similar to  FIG. 4A  but showing the use of end caps in association with the bellows; and 
         FIG. 9  is a cross-sectional view illustrating a modification of bellows-forming discs and their outer flanges to promote cooling. 
     
    
    
     Center lines “CL” as indicated are shown in selected FIGS. as center lines or axes as appropriate for clarity where the construction is symmetrical thereabout. 
     DETAILED DESCRIPTION OF THE INVENTION 
     It should be readily understood that the components and steps of the invention, as generally described and illustrated in the Figures herein and accompanying text, can be arranged and designed in a wide variety of different configurations while still utilizing the inventive concept. 
     For example, the number of disc members and the convolutions of any bellows can be varied as well as their radial and circumferential extension, overlap configuration and the like. 
     Thus, the following more detailed description of the preferred embodiments of the system and method for the present invention, as presented in the Figures and accompanying text, is not intended to limit the scope of the invention, as claimed, but it is merely representative of the presently preferred embodiments of the invention. Moreover, it will be understood that the embodiments described are primarily referred to as “bellows” but particularly and preferably comprise couplings for pipes. 
     The preferred embodiments of the invention will be best understood by reference to the drawings wherein like parts or steps are designated by like numerals throughout. In the FIGS., a dash-dot center line is provided for clarity with the bellows being generally symmetrical thereabout excepting  FIGS. 4 and 4A . 
       FIG. 1  depicts a unitary bellows unit having a plurality of convolutions, each formed by two discs  10 ,  20  ( FIG. 1A ). 
     Referring to  FIGS. 1 and 1A , two discs are adhered to form an inner half  10  of a bellows convolution and an outer half  20  of a bellows convolution. Two or more convolutions may be adhered to form a multi-convolution bellows  5 . The more convolutions added to the bellows, the larger the range of motion, the longer the durability for set deflections, and the lower the stiffness for NVH compensation properties (among other performance criteria of the bellows). 
     Referring to  FIG. 1A , the overlap of the discs  10  and  20  of one convolution  5   a  create the integral outer shield  11  and the overlap of disc  20  from convolution  5   a  and disc  10  from convolution  5   b , form integral inner liner  21 . The bellows  12  is created by adhering (by welding, chemical bonding, or other such method of adhering) two formed (by stamping, molding, cutting or other such forming method) discs  10 ,  20  together to form a convolutions of the bellows  12 . The overlap at the respective adhered ends is used to form the outer shield  11  and/or inner liner  21 . The outer shield  11  serves to provide protection for the bellows  12  from the outside environment and (with additional components) provide extension limits to the bellows. The inner liner  21  serves to protect the bellows  12  from the medium in the piping system, to reduce turbulence and improve NVH properties, and to provide a compression stop. 
     Referring to  FIG. 1B , the inner discs  30  and outer discs  40  and the adhesion method can be designed to minimize the overlap of material and reduce material. A single ply outer shield  31  and a single ply inner shield  41  are provided in a bellows  32 . 
     Referring to  FIG. 1C , the bellows  52  can have inner discs  50  and outer discs  60  to create a bellows  52  with just an outer shield  51 . 
     Referring to  FIG. 1D , the bellows  72  can have inner discs  70  and outer discs  80  to create a bellows  72  with just an inner liner  81 . One or more concave convolutions  75  (view from outside bellows  72 ) define bellows  72 , each convolution defined in part by disc  70  and disc  80 , joined by welding, for example, at the juncture  82  of the respective discs  70 ,  80  forming the respective convolution. 
     Referring to  FIG. 1E , the overlap geometry at  91  of respective inner and outer discs  90 ,  100  can be optimized in a number of ways to facilitate the forming of it (after adhesion) to the inner liner or outer shield as desired.  FIG. 1E  thus illustrates the intermediate configuration of two discs  90 ,  100  as initially joined together and awaiting further forming, bending, etc. of the overlap geometry  91 . 
       FIG. 1F  illustrates that the size of the convolutions can be altered to change the properties of the bellows. As in this figure, the smaller convolution  111  with inner disc  110  and outer disc  120  form a convolution that can be nested between the larger ones  112 ,  113  and allow for greater range of motion (i.e. bending) and NVH properties. Each of the convolutions  111 ,  112 ,  113  are formed by respective discs  110 ,  120 ;  110   a ,  120   a  and  110   b ,  120   b . In this configuration, and for example, overlaps  122 ,  123 ,  124  form partial outer shields while overlaps  126 ,  127  and so on form partial inner liners. 
     Referring to  FIG. 1G , the geometry of the ends of the inner discs  130  and outer discs  140  can be made in a variety of ways to optimize the inner liner  131  or outer shield for the best functional purpose, as illustrated. 
     In all of  FIGS. 1-1G , it will be appreciated the respective shield and liner components are essentially aligned (excepting shields  122 - 124  and liner  131 ). 
     Referring to  FIG. 2 , rods or cables or threaded screws  170  can be threaded through holes in the outer shield  171  (formed by discs such as  150 ,  160 ), such as suggested in  FIG. 1E , to provide NVH damping and/or extension limits. Extension limits set at the rods or cables  170  prevent the bellows from extending beyond the elastic limit of the design. 
     In this regard, and with attention to  FIG. 4A , the support  225  defines an aperture  227  for receiving a hanger  228  in an isolation grommet  229 . 
     Referring to the bellows  175  of  FIGS. 3 and 3A , the inner disc  180  and outer disc  190  are constructed so that the outer shield  195  formed thereby defines a chamber which captures a damping medium  200  (such as mesh wire or a synthetic material) and provide damping properties of the bellows and between the convolutions illustrated. An integral inner shield  196  is formed by interior overlaps of discs  180 ,  190 . 
     Referring to  FIGS. 4 and 4A , the respective discs  210  and  220  of selected convolutions of bellows  200  can be designed with a feature to define a mounting/hinge support  225  as shown in one such case. The thickness of these discs can be different than the others on the bellows of selected convolutions. Also, this convolution can be located at any point along the bellows. The exact mounting configuration is dependent upon the application. 
     Another aspect of this invention includes consideration of and a solution to the interconnection of the elements and structures described above with relatively thicker wall connection pipes or components thereof found in, for example, an exhaust system. 
     More specifically, it will be appreciated that the foregoing flexible elements and bellows apparatus described above have particular applicability to, or use in, exhaust systems for internal combustion engines wherein the pipes or conduits of such systems (not shown), or their connecting structures, are relatively thicker than the members comprising the bellows components or stamping described above. In these and other cases, there is here consideration of how the flexible bellows invention described above are operably interconnected within such systems or to specific connection pipes or other exhaust components. 
     To this end, the invention further contemplates the combination to the bellows described above of end caps configured for welding or other attachment to the ends of the bellows and more particularly to the end bellows component, disc or stamping. The end caps are somewhat thicker than the bellows discs to facilitate welding both to the bellows and to much thicker conduits or pipe components of an exhaust system. 
     This aspect of the invention is illustrated in  FIGS. 5-8 , where  FIG. 5  illustrates in perspective the addition of end caps  250 ,  251  to a bellows  252 , such as that illustrated previously in  FIG. 1G , for example, but wherein the multiple ply flanges  132   a  are not formed over as are flanges  132  of  FIG. 1G . Instead, the flanges are left extending radially outwardly as shown in  FIG. 5 . It will be appreciated that end caps  250 ,  251  each have a radial, outwardly extending flange  253 ,  254 , a body  255 ,  256  and interior, axially extending cylindrical bosses  257 ,  258 . Bodies  255 ,  256  at their outer portions generally correspond partially to the shape of the outer portions of alternative stampings  130   a ,  140   a  respectively as shown. Flanges  253 ,  254  are welded to the outward radial flanges  132   a  of the bellows. End caps  250 ,  251  are preferably thicker than stampings or discs  130   a ,  140   a  for example, but not so thick as to adversely affect their welding to the stampings. At the same time, cylindrical bosses  257 ,  258  are thick enough for welding to the end connections of pipes, tubes or conduits in an exhaust system, for example. 
     Details of  FIG. 5  are also shown in  FIG. 6 , wherein only the half of the bellows  252  and end caps  250 ,  251  are illustrated in side view cross-section as shown for clarity. The bellows  252  and end caps  250 ,  251  are developed about center line CL with inner liner flanges  131   a  extending inwardly as shown. 
     End caps somewhat similar to these as described are useful on flexible bellows of a variety of configurations as described above. 
     For example,  FIG. 7  illustrates an end cap  270  used with a bellows  271  of similar configuration to that shown in  FIG. 1A . In  FIG. 7 , only one end cap  270  is shown in partial cross-section on the bellows  271 , it being understood another end cap is used on the opposite end of the bellows  271 . 
     In  FIG. 7 , end cap  270  has a body  272  configured at its upper end like bellows disc or stamping  20   a , and a flange  273  along upper flange  11   a  of disc  10   a . The end cap  270  has an interior, axially extending cylindrical boss  274  for connection to a pipe tubing or conduit of an exhaust system (not shown), for example. 
     The thickness of caps  270  is thicker than discs  10   a ,  20   a , but not so much as to interfere with welding of flange  273  to flange  11   a . In addition, its thickness facilitates its welding or connection into the thicker, more robust components of an exhaust system. For clarity, only a portion of bellows  271  end cap  270  are shown about center line CL, similar to  FIG. 6 . 
       FIG. 8  illustrates a bellows  290  such as that bellows of  FIG. 4A , but with end caps  291 ,  292  all developed about center line CL. 
     End caps  291 ,  292  have radially extending flanges  293 ,  294  welded respectively to flanges  295 ,  296  of bellows  290  as shown, with all flanges in this configuration extending radially outwardly from center line CL. 
     End caps  291 ,  292  have bodies  297 ,  298  formed at their upper ends like discs  220   a  and  210   a , respectively, and interior, axially extending cylindrical bosses  299 ,  230  for interconnection to the components of an exhaust system, for example. 
     Other components are numbered and are like that of  FIG. 4A . 
     In a yet further aspect of the invention, it will be appreciated that the outward extending flanges of the various bellows configurations of the embodiments described herein can be welded together, then fluted or splayed away from one another to present more surface area to the surrounding environment to promote cooling of the bellows and systems in which they are used. Thus, for example, the outward flanges shown in  FIGS. 1A ,  1 C,  1 E,  1 F,  1 G,  4 A,  5 ,  6 ,  7  and  8  could be so arranged. 
       FIG. 9  illustrates this aspect of the invention wherein is shown two discs  310 ,  312  defining a convolution of a multiple component bellows (such as those shown in various preceding FIGS.). Discs  310 ,  312  have outwardly extended, but splayed apart, flanges  314 ,  316  extending beyond weld  317  to present additional surface area exposed to the environment for cooling. Otherwise, the bellows and discs are similar to those described above. 
     These and other alternatives, modifications and advantages will become readily apparent to those of ordinary skill in the field to which this invention pertains and applicant intends to be bound only by the claims appended hereto.