Abstract:
A pneumatically assisted inflator for gas cylinders comprises an inline configuration such that gas contained within the gas cylinder flows axially through the inflator to be exhausted therefrom and inflate an inflatable article. The inline configuration of the inflator reduces the stress otherwise imparted to the component parts thereof and thereby allows most of the component parts to be manufactured from an injection molded high-strength plastic or the like. The inflator comprises an inflator piston positioned within a piston cylinder that moves against a rotatable cam surface, such as a rotatable collar connected to a pull lanyard, to force a pierce pin to make at least a small pin hole in a frangible seal and allow high pressure gas from the gas cylinder to flow into the piston cylinder, whereupon the high pressure gas in the piston cylinder further moves the inflator piston to more fully force the pierce pin into the frangible seal to fully open the frangible seal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of Ser. No. 10/935,944 filed Sep. 8, 2004, now U.S. Pat. No. 7,178,547 issued Feb. 20, 2007, which claims priority of provisional application No. 60/501,297, filed Sep. 8, 2003, the disclosures of which are each hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to inflation valves for compressed gas cylinders used for inflating inflatable articles such as life rafts. More particularly, this invention relates to inflation valves that utilize the pressure of the gas in the gas cylinder to assist in the opening of the valve to a fully-open position by pulling on an inflation handle. 
     2. Description of the Background Art 
     Presently, there exists many types of inflation valves designed to be used in conjunction with compressed gas cylinders or the like. In their simplest forms, inflation valves may comprise a knob or handle which is turned to open a flow passageway allowing the compressed gas within the cylinder to inflate the inflatable article. However, even more prevalent are inflation valves for sealed gas cartridges that are operable by means of a jerk handle and lanyard cord that allow the inflatable article to be quickly inflated by a simple jerking of the handle which forces a pierce pin to fracture the frangible seal of the gas cartridge allowing the compressed gas therein to flow to and inflate the inflatable article. 
     Due to the large force necessary to fracture the frangible seal of a conventional gas cylinder, more contemporary designs of inflation valves employ a powerful spring which is held in its cocked position by means of a sear. Upon jerking of the jerk handle by the user, the sear is released allowing the powerful spring to very forcibly force the pierce pin through the frangible seal of the gas cartridge. 
     To eliminate the need for inflators having powerful firing springs held in cocked positions, still more contemporary inflation valves utilize the internal pressure of the gas cylinder to assist in driving the pierce pin fully through an internal frangible seal. A representative inflation system with such a pneumatic assist feature, is disclosed in my U.S. Pat. No. 6,089,403, the disclosure of which is hereby incorporated by reference herein. However, there presently exists a need for pneumatically assisted inflators that are configured in such a manner that virtually all of the components thereof may be manufactured from a high-strength, injectable plastic thereby obviating the need for extensive machining of metal parts and the attendant manufacturing and assembly costs thereof. 
     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 inflation art. 
     Another object of this invention is to provide an inflator with pneumatic assist that is configured in such a manner that its component parts may be manufactured from an injectable high-strength plastic material. 
     Another object of this invention is to provide an inflator with pneumatic assist having an inflator body removable from a valve body such that the valve body may be mounted on the gas cylinder and the gas cylinder filled with compressed gas and then at some later point in time, the inflator body installed thereon. 
     Another object of this invention is to provide a pneumatically assisted inflator having an inline configuration such that the O-ring seal of the pneumatic piston does not wipe across the exhaust port as taught by my prior patent, U.S. Pat. No. 6,089,403. 
     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 
     For the purpose of summarizing this invention, this invention comprises a pneumatically assisted inflator for gas cylinders. The inflator of the invention uniquely comprises an inline configuration such that gas contained within the gas cylinder flows axially through the inflator to be exhausted therefrom and inflate the inflatable article. The inline configuration of the inflator of this invention reduces the stress otherwise imparted to the component parts thereof, and thereby allows most of the component parts to be manufactured from an injection molded high-strength plastic or the like. 
     Moreover, the inline configuration of the present invention eliminates the need for the O-ring seal of the inflator piston to wipe across the exhaust opening possibly bursting the O-ring through the exhaust opening. Further, possible damage to the O-ring by the edge of the exhaust hole as it is explosively wiped thereacross is eliminated. 
     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 
       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: 
         FIG. 1  is a perspective view of the inflator of the invention; 
         FIG. 2  is a side elevational view of the inflator of the invention; 
         FIG. 3  is another perspective view of the inflator of the invention showing several of the components thereof in shaded phantom; 
         FIG. 4  is a longitudinal cross-sectional view of the inflator of the invention with its inflator position in its “at ready” position; 
         FIG. 5  is a perspective view of the inflator piston; 
         FIG. 6  is a longitudinal cross-sectional view of the inflator of the invention with the inflator piston in its pin-hole piercing position; 
         FIG. 7  is a longitudinal cross-sectional view of the inflator of the invention with the inflator piston in its fully fired position with its pierce pin fully fracturing its internal frangible seal; and 
         FIG. 8  is a longitudinal cross-sectional view of the inlet valve. 
     
    
    
     Similar reference characters refer to similar parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2 , the inflator  10  of the invention comprises a valve portion  12  to which is threadably coupled an inflator portion  14 . As will become evident hereinafter, the valve portion  12  may be threadably coupled to the threaded neck of a gas cylinder  13  (shown in phantom) to then be filled via inlet  15  without necessarily requiring the installation of the inflator portion  14 . Then, after the gas cylinder  13  has been filled with the appropriate gas, the inflator portion  14  may be installed by simple threaded engagement with the valve portion  12 . 
     The inflator portion  14  comprises a rotatable inflator collar  16  having a side opening  18  through which is threaded a lanyard cord  20  of a conventional jerk-to-inflate handle  22 . The end of the lanyard cord  20  is connected to a rotatable cam  16 C positioned inside the collar  16 . The underside of the rotatable cam  16 C including a cam surface  16 S. 
     As shown in  FIGS. 3 and 4 , the inflator portion  14  further comprises an inflator piston  24  having hollow pierce pin  32  with a pointed tip  30 , which are as an assembly reciprocatably mounted within a piston cylinder  26  in alignment with the internal frangible seal  28  of the valve portion  12 . The inflator piston  24  is in operative engagement with the cam surface  16 S to move inwardly as the cam  16 C is rotated. 
     In operation, upon pulling of the jerk handle  22 , cord  20  causes the rotatable cam  16 C inside the collar  16  to rotate. Upon rotation of the cam  16 C, inflator piston  24  is forced downwardly until the very tip  30  of the hollow pierce pin  32  coupled to the inflator piston  24  makes a small pin-hole in the frangible seal  28  of the valve body  12  (see also  FIG. 6 ). Upon making the pin hole opening in the frangible seal  28 , the high-pressure gas contained within the gas cylinder  13  flows therefrom through the inflator piston  24  to pressurize the top portion of the piston cylinder  26  above the inflator piston  24 , whereupon the inflator piston  24  is then forced by the high-pressure gas further downwardly to fully drive the pierce pin  32  through and hence fully open the frangible seal  28  (see  FIG. 7 ). 
     Upon fully piercing the frangible seal  28 , a full flow of escaping gas from the gas cylinder flows through the pierce pin  32  and exits therefrom via side openings  32 S to then flow through center bore  34 B of the connector boss  34  to which an inflation tube may be threadably coupled. 
     Referring to  FIG. 5  in conjunction with  FIGS. 4 ,  6  and  7 , the inflation piston  24  comprises two upstanding arms  24 A with bearing surfaces  24 S which cam against the cam surface  16 S of the collar  16  as it is rotated upon pulling of the lanyard handle  22 . Correspondingly, the piston cylinder  26  comprises two ports  26 P configured and dimensioned to slidably receive the upstanding arms  24 A and allow reciprocal movement thereof. The inflation piston  24  further includes a depending neck  24 DN that is configured and dimensioned to slidably engage into a reduced-diameter portion  26 N of the piston cylinder  26 . Finally, the inflation piston  24  further includes an upstanding neck  24 UN that is configured and dimensioned to slidably engage into the longitudinal bore  34 B formed in the connection boss  34 . 
     Both of the upstanding arms  24 A may be provided with O-ring slots and O-rings  240 A to prevent leakage of gas through the ports  26 P into the collar  16 . Likewise, inflation piston  24  may be provided with an O-ring slot and O-ring  240 C for sealing against the lumen of the piston cylinder  26 . The depending neck  24 DN of the piston  24  may be provided with an O-ring slot and O-ring  240 P to seal the depending neck  24 DN within the reduced diameter portion  26 N of the cylinder  26 . The upstanding neck  24 UN of the inflator piston  24  is sealed against the lumen of the longitudinal bore  34 B by means of an annular wiper seal  38 . Finally, as shown, the frangible seal  28  is sealed within the valve portion  12  by means of a corresponding O-ring slot and O-ring  280 . 
     The operation of the inflator  10  of the invention is best seen upon comparison of  FIGS. 4 ,  6  and  7  wherein  FIG. 4  depicts the inflator piston  24  at its “cocked” position;  FIG. 6  illustrates the inflator piston  24  moved slightly downwardly to make a pin hole in the frangible seal  28 ; and  FIG. 7  illustrates the inflator piston  24  forced fully downwardly to fully fracture the frangible seal  28  allowing full flow of pressurized gas therethrough. 
     More particularly, in its “cocked” position as shown in  FIG. 4 , the inflator piston  24  is positioned within the piston cylinder  26  and sealed with the lumen thereof by means of the O-ring  240 C. In this position, the bearing surfaces of two upstanding arms  24 A bear against the cam surface  16 S of the collar  16  and are sealed within the respective ports  26 P by means of the O-ring  240 A. The upstanding neck portion  24 UN is positioned fully upward within the longitudinal bore  34 B and is sealed therewith by means of the annular wiper seal  38 . The depending neck  24 DN is inserted within the reduced diameter portion  26 N and sealed therewith by means of the O-ring  280 P. 
     Referring now to  FIG. 6 , upon pulling of the jerk handle  22  to “fire” the inflator  10 , the rotatable collar  16 C is caused to rotate whereupon its cam surface  16 S cams against the bearing surfaces  24 S of the upstanding arms  24 A forcing them downwardly toward the interior of the inflation valve  10 . The degree of taper of the cam surface  16 S relative to the dimensions of the inflator piston  24  and the frangible seal  28  are such that upon full rotation of the rotatable cam  16 C, the tip  30  of the pierce pin  32  makes a small pin hole in the frangible seal  28 . The pin hole thus formed allows high pressure gas from the gas cylinder  13  to flow through the longitudinal bore  12 B from the pierced frangible seal  28  through the pierce pin  32  and exiting the side openings  32 S. Since the longitudinal bore  32 B is sealed by means of the wiper seal  38 , the gas pressurizes the uppermost portion  26 U of the cylinder  26 . 
     As shown in  FIG. 7 , as the uppermost portion  26 U of the cylinder  26  is pressurized, the inflation piston  24  is forcibly urged further inwardly to a position in which the pierce pin  32  completely fractures the frangible seal  28  of the inflator  10 . Once the frangible seal  28  is fully pierced and hence fully open, a full flow of compressed gas from the cylinder  13  is allowed to flow through the pierce pin  32  to exit therefrom via openings  32 S into the upper portion of cylinder  26 . Moreover, since the wiper seal  38  has now moved fully out of the longitudinal bore  34 B, the escaping gas flows from the upper portion  26 U of the cylinder  26  into the longitudinal bore  34 B to inflate the article to be inflated that is fluidly connected to the connector boss  34 . It is noted that in this fully opened position, gas is precluded from escaping from the ports  26 P by O-rings  240 . 
     Returning now to  FIG. 4 , it should be appreciated that the valve portion  12  may be threadably coupled to the threaded neck of the gas cylinder  13  without necessarily requiring the installation of the inflator portion  14 . Specifically, once the valve portion  12  is threadably coupled to the threaded neck of the gas cylinder  13 , the gas cylinder  13  may be filled via inlet  15  and fill port  15 P connected in fluid communication with the longitudinal bore  12 B of the inflator portion  12 . Since the longitudinal bore  12 B is sealed by means of the frangible seal  28  of the inflator portion  12 , the fill air is forced into the gas cylinder  17  and is not allowed to escape therefrom. Once filled, the fill inlet  16  may be closed by means of a valve (not shown), which may comprise a check valve allowing filling but not discharging of air from the gas cylinder  13 . The inflator portion  14  of the inflator  10  of the invention may then be threadably connected to the valve portion  12  by means of thread  12 T. Conversely, removal of the inflator portion  14  from the valve portion  12  may be allowed for periodic inspection during maintenance. 
     Referring to  FIG. 8 , a preferred embodiment of the inlet valve  15  comprises a generally circular cylindrical body  52  with external threads  52 T. The exposed proximal end  54  of the inlet valve  15  comprises a hex configuration for grasping by a suitable wrench. The internal distal portion end  56  of the inlet valve comprises a shank portion  58  and a reduced-diameter portion  60 . The shank portion  58  includes an O-ring groove  58 G for receiving an O-ring  580 . The reduced-diameter portion  60  likewise includes an O-ring groove  60 G for receiving an O-ring  600 . 
     The proximal end  54  of the inlet valve  15  includes a threaded central bore  62  for receiving a fill hose or the like. A central reduced-diameter bore  64  extends from the bottom of the central bore  62  to be in fluid communication with a transverse hole  66  formed through the shank portion  58  of the inlet valve  15  forward of its O-ring groove  58 G. 
     As best seen in  FIGS. 3 and 4 , an inlet hole  68  is formed in the wall of the valve portion  12 . The inlet hole  68  includes a proximal threaded portion  68 T for threadably receiving the external threads  52 T of the generally circular cylindrical body  52 . The distal end  70  of the inlet hole  68  includes a generally circular cylindrical portion  72  and a generally frustro-conical portion  74  that extends into the port  15 P of the longitudinal bore  12 B. 
     The generally circular cylindrical portion  72  is dimensioned to sealingly receive the shank portion  58  by virtue of its O-ring  580 . The generally frustro-conical portion  74  is shaped to allow the O-ring  600  of the reduced-diameter portion  60  to seal against it when the inlet valve  15  is fully threaded into the inlet hole  68  and to allow venting of pressurized gas from the longitudinal bore  12 B when the inlet valve  15  is slightly threaded outwardly to crack the seal between the O-ring  600  and the frustro-conical portion  74  whereupon the pressurized gas is allowed to vent via transverse hole  66  through central bore  62 . 
     After sufficient bleeding of the pressurized gas to reduce its pressure, further outward threading of the inlet valve  15  to a point where the O-ring  600  moves into the generally circular cylindrical portion  72  allows full fluid flow through transverse hole  66  through central bore  62  for subsequent filling via inlet valve  15 . 
     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. 
     Now that the invention has been described,