Abstract:
A check valve comprising a poppet urged by a conical spring to annularly seal uniformly around its entire periphery to assure more uniform cracking pressure about its entire periphery. The cracking pressure may be adjusted by means of an adjustable plate which reduces the length of the conical spring and thereby increase the amount of force exerted by the spring onto the poppet into sealing engagement, thereby increasing the cracking pressure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority of provisional application No. 60/501,296, filed Sep. 8, 2003, the disclosure of which is hereby incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to check valves. More particularly, this invention relates to check valves having presettable and adjustable cracking pressures.  
         [0004]     2. Description of the Background Art  
         [0005]     Presently, there exist many types of check valves designed to allow the flow of a fluid such as a gas in one direction but to block or “check” the flow of the fluid in the opposite direction. The amount of fluid force required to open the poppet of the valve in the un-checked direction is often referred to as the cracking pressure. Typically, the cracking pressure of a check valve is determined by the spring constant of the internal spring which constantly urges the poppet into a sealing position until unseated therefrom once the cracking pressure is attained.  
         [0006]     A predetermined cracking pressure of a check valve is desired when check valves are used in conjunction with inflatable articles such as life vests and life rafts. Specifically, a check valve having a predetermined cracking pressure allows the inflatable to be inflated by means of a gas cartridge or the like to assure that the inflatable is inflated to a preset internal pressure. Thus, by allowing excess gas to be exhausted, over-capacity gas cartridges can be employed to inflate the inflatable to ensure that the inflatable is fully inflated to a preset internal pressure in all environments.  
         [0007]     Therefore, it is an object of this invention to provide an improvement which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the oral inflation art.  
         [0008]     Another object of this invention is to provide a check valve having an increased flow rate.  
         [0009]     Another object of this invention is to provide a check valve having a structure composed of a minimal number of parts to increase its reliability while decreasing cost of manufacture and assembly.  
         [0010]     Another object of this invention is to provide a check valve having a design that equalizes the sealing force of the poppet around its entire periphery to assure that the check valve is cracked uniformly about the periphery of the poppet.  
         [0011]     The foregoing has outlined some of the pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.  
       SUMMARY OF THE INVENTION  
       [0012]     For the purpose of summarizing this invention, this invention comprises a check valve having a simple design with fewer parts than conventional prior art check valves to achieve increased reliability while reducing manufacturing and assembly costs. The check valve of the invention further achieves an increased flow rate upon cracking due to its simplistic yet ingenious design.  
         [0013]     Finally, the poppet of the check valve of the invention cooperates with a conical spring to assure that it seals uniformly around its entire periphery facilitating more uniform cracking pressure about its entire periphery.  
         [0014]     In another embodiment of the check valve of the invention, the cracking pressure is adjustable by means of a threaded adjustable plate which cooperates with the conical spring to reduce the length thereof and thereby increase the amount of force exerted by the spring onto the poppet into sealing engagement, thereby increasing the cracking pressure.  
         [0015]     The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:  
         [0017]      FIG. 1  is a perspective view of the first embodiment of the check valve of the invention;  
         [0018]      FIG. 2  is a perspective view, partially cut-away, of the first embodiment of the invention;  
         [0019]      FIG. 3  is a perspective view, partially cut-away, of the first embodiment of the invention;  
         [0020]      FIG. 4  is a perspective view of the second embodiment of the check valve of the invention;  
         [0021]      FIG. 5  is a cross-sectional view of  FIG. 5  along lines  5 - 5 ; and  
         [0022]      FIG. 6  illustrates an alternative embodiment of centering the conical spring to assure uniform sealing of the poppet. 
     
    
       [0023]     Similar reference characters refer to similar parts throughout the several views of the drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]     The check valve  10  of the invention comprises a body  12  to which is mounted a cap  14  having a plurality of flow openings  16  about its periphery allowing fluid to flow in the direction of arrows  18  through the body  12  to then be exhausted from the check valve  10  via openings  16  as shown by arrows  20 .  
         [0025]     Body  12  may be connected about an opening in an inflatable, shown in phantom by reference numeral  22 , through the use of a threaded flange  24  that sealingly captures the edge  26  of the opening in the inflatable  22 .  
         [0026]     As shown in  FIGS. 2 and 3 , check valve  10  of the invention comprises a poppet  30  having an annular groove  32  in which is positioned an annular O-ring  34  that seats on an annular seat  36  formed at the end of the lumen  38  of the body  12 .  
         [0027]     The poppet  30  includes a concave portion  46  having an upstanding protrusion  42  extending from the inside center thereof. Protrusion  42  comprises four interior webs  42 W positioned at 90 degree intervals and forming a semi-spherical outer configuration. Poppet  30  further comprises three exterior webs  44 , slightly tapered inwardly, from the lumen  38  of the body  12 .  
         [0028]     Cap  14  comprises a plurality of tabs  14 T that snap into corresponding slots formed in the outer periphery of the cap  12  to securely retain the cap  14  into position. Cap  14  further comprises a plurality of downwardly extending legs  14 L, such as three positioned at 120 degree intervals, to entrain the poppet  30  therebetween. The legs  14 L coupled with the exterior webs  44  assure that the poppet  30  may reciprocate upwardly within cap  14  without tilting sideways out of alignment where it may potentially jam.  
         [0029]     Finally, the check valve  10  of the invention comprises a conical spring  50  having its uppermost largest diameter coil  50 L captured by an annular step  14 S formed in the underside of the cap  14 . The lowermost smallest diameter coil  50 S is dimensioned to be appreciably less in diameter than the outer diameter of the protrusion  42  such that when the coil  50 S is seated thereon, poppet  30  is allowed to pivot universally in all directions. The ability of the poppet  30  to pivot universally by virtue of the protrusion  42  pivoting within the coil  50 S, assures that the O-ring  34  of the poppet  30  will be forced into sealing engagement with the annular seat  36  in a highly uniform manner about its entire periphery. Consequently, uniform cracking of the poppet  30  about its entire periphery is achieved.  
         [0030]     Referring now to  FIGS. 4 and 5 , the second embodiment of the check valve  10  of the invention comprises a similar body  12  with a cap  14  having flow openings  20  allowing fluid flow  18  to flow through the valve  10  in the unchecked flow direction. Similarly, the second embodiment of the check valve  10  of the invention comprises a conical spring  50  entrained between the cap  14  and a poppet  30  to urge its O-ring  34  in sealing engagement with the annular seat  36 .  
         [0031]     The poppet  30  further includes exterior webs  44  which prevent the poppet from becoming canted with the lumen  38 . However, due to the specific configuration of the cap  14 , in the second embodiment, the downward depending legs  14 L of the cap  14  of the first embodiment need not be included since the annular groove  32  moves in alignment with the lumen  52  of the cap  14 .  
         [0032]     In the second embodiment, poppet  30  similarly includes an upstanding center protrusion  42  with four webs  42 W forming an outer semi-spherical configuration on which is seated the lowermost smaller diameter coil  50 S of the spring  50 .  
         [0033]     Unlike the first embodiment, the second embodiment of the check valve  10  comprises an adjustable plate  60  having a center boss  62  with external threads  64  for threaded engagement with a threaded hole  66  formed in the center of the cap  14 . Boss  62  may be provided with a hex indentation  63  for receiving a hex or other tool.  
         [0034]     Plate  60  extends in a somewhat planar configuration from the boss  62  to a position between the uppermost larger diameter spring coil  50 L and the underside of cap  14 . Upon rotation of the boss  62  in a clockwise direction, plate  60  is caused to move inwardly to further compress the conical spring and thereby increase the cracking pressure of the check valve  10 . The outer periphery of the plate  60  may be provided with radial protuberances  60 P to engage into openings  20  and provide indexing of the plate  60  as the plate  60  is rotated to adjust the cracking pressure. The protuberances  60 P may be of the same width as the openings  20  or, if smaller, may be asymmetrically positioned to provide accurate indexing.  
         [0035]      FIG. 6  illustrates an alternative embodiment for free-floating of the poppet  30  to assure uniform annular indexing of its O-ring  34  on annular seat  36 . Specifically, protrusion  42  is configured to achieve a conical apex point for universal engagement into a corresponding center seat  62  formed in a balance plate  60 . The balance plate  60  assures that only a central force is exerted onto the poppet  30  thereby achieving uniform annular sealing.  
         [0036]     The present disclosure includes that contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.  
         [0037]     Now that the invention has been described,