Abstract:
Respectively tapered and threaded pipe ends are rotated respective to each other to connect the pipe ends and progressively compress a yieldable damper sleeve therebetween as the pipes are rotated. NVH and torsional forces from one pipe end to another are suppressed.

Description:
RELATED APPLICATION 
       [0001]    Applicant claims the benefit of U.S. provisional patent application Ser. No. 61/052,664 filed May 13, 2008 and entitled “Adjustable Tubular NVH Dampener and Torsion Absorber” which application is herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to the coupling of pipes or conduits used in a piping system and more particularly to apparatus and methods for damping noise, vibration and harshness (NVH) and torsional forces transferred from one pipe coupled to another. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is known to connect a male tapered-down externally threaded portion of one pipe by rotating it into a flared internally threaded female end of another pipe. While this couples the two pipes together, NVH and torsional forces are transmitted across this coupled area from one pipe to the other. 
         [0004]    Existing prior devices provide damping between two pipes via cushion material, but the systems with which such damping devices are used have their own range of vibration noise and harshness parameters. Frequencies vary significantly between systems, such that a damper and torsional absorber optimized for one system will not be so efficient for another. 
         [0005]    It is accordingly desired to provide coupling apparatus and methods for securing a variety of respective male and female pipe ends together while, at the same time, suppressing or diminishing NVH and torsional forces transmitted from one pipe to the other. 
       SUMMARY OF THE INVENTION 
       [0006]    To these ends, a preferred embodiment of the invention contemplates a coupling area with internal and external threads on respective female and male pipe ends in a relationship where a gap between the threads diminishes as the coupling is formed and compresses a damper insert of yieldable damper material therebetween the overlap of pipe ends at the coupled area. The coupling so provided can be adjusted to preload the damper and adjust the suppression characteristics of the coupling to the pipe system being coupled together. 
         [0007]    With more particularity, the taper angle of the threaded portion of the respective pipe ends and the pitch of threads is selected so the gap size formed between the respective threads is reduced at a different rate compared to the amount respective rotation of the pipe ends. Taper angle and thread pitch are thus combined to produce a desired damper preload on the damper sleeve between the respective pipe ends. That preload then determines the degree of joint stiffness and friction characteristics of the coupling area and therefore its damping rate. Compensation is thus provided for NVH and torsion damping and deflection in an adjustable structure and for a variety of pipe systems. 
         [0008]    Thus, the invention contemplates a semi-flexible connection with variable and highly progressive friction damping for pipes subject to vibration transmission, to torsional loads, or both. This friction damping suppresses or reduces resonance nodes and compensates for NVH. This invention thus integrates the connection of the ends of two tubular fluid conduits. The ends are formed in a tapered shape in which one male pipe end is tapered, featuring a diameter reduction, and the other receiving female pipe end is tapered outwardly with increasing diameter. In order to hold the connection in place, the invention contemplates a damping sleeve disposed between the pipe ends and the respective threads thereof. The damper is preloaded as a function of the amount of relative pipe rotation. 
         [0009]    These and other objects and advantages will become readily apparent from the following written description and from the drawings in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is an isometric view of an assembled adjustable tubular NVH dampener according to the invention; 
           [0011]      FIG. 1A  is a exploded isometric view of the invention of  FIG. 1  with the matting/damping/cushion material illustrated between two pipe ends; 
           [0012]      FIG. 1B  is a cross-section view of the invention as shown in  FIG. 1  with the matting/damping/cushion between the pipe ends; and 
           [0013]      FIG. 1C  is an enlarged view of the highlighted portion of  FIG. 1B , showing features of the invention in more detail. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    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. 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, but it is merely representative of the presently preferred embodiments of the invention. 
         [0015]    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. 
         [0016]    Referring now to  FIG. 1 , there is disclosed therein an illustrative view of the two respective pipes  10 ,  20 , coupled together in a coupling zone identified at  30 . 
         [0017]      FIG. 1A  illustrates in exploded form the respective pipe ends  10   a ,  20   a  and the damping insert  40  which is not shown in  FIG. 1 . Pipe end  10   a  is a radially inwardly tapered male pipe end having external threads  50  therealong. Pipe end  20   a  is a radially outwardly flared female end having internal threads  60  therein. 
         [0018]    Damping insert  40  is a sleeve which may preferably be slightly tapered similarly to pipe ends  10   a ,  20   a . Sleeve  40  may also be supplied with external and internal threading similar to that of the pipe ends  10   a ,  20   a . in use, when the pipes  10 ,  20  are coupled as in  FIG. 1 , damping insert  40  resides between ends  10   a ,  20   a , as will be described. 
         [0019]    Turning now to  FIGS. 1B and 1C , the details of the threaded ends  10   a ,  20   a  will be described.  FIG. 1B  is a cross-sectional view showing the relation of male end  10   a  to female end  20   a . External threads  50  on male end  10   a  loosely mesh, or are indexed therewith, internal threads  60  of female end  20   a  and about axis  70 , pipes  10  and  20  being essentially coaxial. It will be appreciated that the outermost portion of flared end  20   a  is about the same outer diameter of that of pipe  10 . The innermost tapered portion of end  10   a  is about the same inner diameter of pipe  20 . These dimensions may be closer to each other or further apart as desired. In any event, it will be appreciated that end  10   a  can be rotatably threaded into end  20   a.    
         [0020]      FIG. 1C  illustrates in enlarged view for clarity that selected portion of  FIG. 1B .  FIG. 1C  further illustrates the relation of components of the invention. First, it will be appreciated that angle  75  is a taper angle illustrating the angle of taper between the inwardly tapered end  10   a  of pipe  10  and an arbitrary line  70   a  which is a parallel to axis  70 . Both ends  10   a  and  20   a  are preferably disposed on this taper angle. 
         [0021]    It will also be appreciated that the threads  50  and  60  have a pitch illustrated by the line  80  in  FIG. 1C , and that when the pipe ends  10   a ,  20   a  are rotated respectively, an undulating gap  90  is formed between the projecting portions  50   a  of threads  50  and concave portions  60   a  of threads  60 . Gap  90  is undulating and varies in width as it extends along and between threaded portions  50  and  60 . 
         [0022]    The damping member  40  is disposed over end  10   a  and fits within end  20   a , such that it resides in gap  90  between threads  50  and  60 . As the pipes  10 ,  20  are respectively counter-rotated, end  10   a  is threaded into end  20   a , with the respective threads engaging to compress damper  40  between ends  10   a ,  20   a.    
         [0023]    Referring to the Figures above,  FIG. 1  illustrates two tube ends  10  and  20 , connected via the threaded area  30  (defined by male  50  and female  60  tapered threads) ( FIG. 1A ) to enclose the matting/damping/cushion material  40 . 
         [0024]    By relatively rotating the tubes  10  and  20  in opposite directions the gap  90  between the respective threads ( FIG. 1C ) is increasingly reduced. Depending on the taper angle  75  and the pitch  80  of the threads  50 ,  60 , the gap  90  size is reduced in a different rate compared to the amount of rotation. The gap  90  captures the damping or cushion material  40 . By reducing the gap with turning of the threads, the cushion material  40  is progressively compressed or preloaded. Again the taper angle  75  and the thread pitch  80  determine the force or preload that is applied to the damping or cushion material  40 . In turn, the preload determines the stiffness and friction characteristics of the connection and therefore its dampening rate. 
         [0025]    It will be appreciated that the tapered threads  50 ,  60 , upon progressing rotation of ends  10   a ,  20   a , come respectively closer and closer together, narrowing gap  90  and further compressing the intermediate damper sleeve  40 . Thus, the undesirable frequencies and NVH parameters of the system can be damped from system to system without specific design or construction features requiring different mechanisms for optimal damping. 
         [0026]    Alternately, relative thread pitch of threads  50 ,  60 , type of thread and taper angle can all be adjusted or varied as desired. 
         [0027]    This invention contemplates an adjustable structure that can be adapted to problematic modes of specific applications. Unlike prior devices, it additionally allows for torsional dampening and torsional deflection compensation. 
         [0028]    The invention is made with a variety of materials and thicknesses of the materials for conical tubular structure. The damper may comprise one or multiple plies of various types and shapes of cushion material. In addition to the NVH damping benefits the present invention can improve assembly ease for complex piping systems. 
         [0029]    Materials for both pipes, threaded ends and cushion are selected from any suitable synthetic or other suitable types or compositions. 
         [0030]    Finally, it will be appreciated that the tolerances and depiction of the components of the invention as shown in the Figures are for clarity of illustration only, and are not to scale, and actual tolerances may vary. 
         [0031]    Thus, in conjunction with one or more torsion absorbers or coupling areas according to the invention, the aggressive dynamic modes of harshness, noise and vibrations (NVH) existent in a sensitive tubular system can be manipulated for under or over critical behavior and torsional loads can be absorbed. 
         [0032]    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.