Abstract:
A tubular and compressible seal attached to one tube and formed with a cowling projecting over a peripheral bead in a second tube and formed with a rearwardly inwardly projecting sealing ring engaging such second tube. A constraining sleeve compressing the cowling and sealing ring against the second tube.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention:  
         [0002]     The present invention relates to connectors for connecting sections of ducting together.  
         [0003]     2. Description of the Prior Art:  
         [0004]     Airframe construction in the aerospace industry typically employs numerous tubes and ducts for flowing fluids and gasses to different areas of the airframe for numerous different purposes. These ducts are utilized to convey moderate and high-pressure (5-100 psi) fluids and even partial vacuum within the aircraft. Sections of the ducts are connected together at various locations, often times as assembly of the air or spacecraft is nearing completion. It has been common practice to make these connections by forming a tube or duct with an exterior bead which may facilitate connection with a joining duct section by application of a metallic clamp over an adjoining cuff, typically with screw fasteners. The task of connecting tubes and ducts in this matter is time consuming and, considering the numerous number of such connections made in modem day jumbo aircraft, can add significantly to the labor costs and the expense of manufacture.  
         [0005]     These prior art devices often employ a thin-walled rubber cuff and reinforced by helically wound wire or other reinforcement and configured to be slid over a exterior bead on an adjoining tube or duct. An adjustable clamp such as a steel worm clamp is positioned in radially alignment based actually behind the bead and tightened to draw the off cuff down on the connecting bead in effort to provide a fluid tight seal. Such devices typically require some space about the tubing for the workman to rotate the clamp and make a firm final connection. Generally, prior art quick disconnect fittings of this type are of a relatively heavy construction, complex and bulky thus limiting usage in aircraft construction.  
         [0006]     Many of these prior art connectors are designed to connect tubes together for conveying fluids under either positive or negative pressure, but not both.  
         [0007]     There exists a need for a relatively inexpensive quick disconnect device for conveniently and positively connecting tube sections together in leak free fashion. It is this need to which the present invention is directed.  
       SUMMARY OF THE INVENTION  
       [0008]     The quick disconnect of the present invention includes an elongated tubular seal device constructed to span the juncture point between first and second tubes wherein one of the tubes is formed with an exterior sealing bead. The seal device is mounted from the other tube but is configured with a cowling which passes over the bead and includes a radially inwardly projecting sealing ring which is compressed radially inwardly by means of a concentric shell constructed to slide axially over the cowling and press the ring radially inwardly against the one tube.  
         [0009]     Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the features of the invention 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a pair of tubes to be connected together by the quick disconnect apparatus of the present invention;  
         [0011]      FIG. 2  is a perspective view similar to  FIG. 1  but showing the tubes connected together;  
         [0012]      FIG. 3  is a front view of the quick disconnect shown in  FIG. 2 ;  
         [0013]      FIG. 4  is a longitudinal sectional view, in enlarged scale, taken along the line  4 - 4  of  FIG. 3  and showing the disconnecting in its coupling position; and  
         [0014]      FIG. 5  is a sectional view similar to  FIG. 4  but depicting the disconnect apparatus in its uncoupled position.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     Ducts and tubing of widely varying diameters are used for circulating fluids in aerospace vehicles. The various ducts and tubing sections must be connected together during the assembly stage, often anytime when assembly of the overhaul vehicle is nearing completion and production time is of a concern. Tubes  11  and  13  typically have a diameter on the order of 2 to 3½ or 4 inches but may vary over broad ranges. The quick disconnect of the present invention includes, generally, a tubular seal device  17  mounted to the tube II and projecting axially therefrom to form a cowling  19  to be received slidably over a bead  21  formed in the tube  13  and, in practice, is formed at its open end with a radially inwardly projecting sealing ring  25  which is selectively pressed radially inwardly by means of a slider shell  27  to capture the bead  21  behind the ring  25  and compress such ring to form a fluid tight seal.  
         [0016]     The bead  21  may be formed in the tube  13  or may be welded to the exterior surface thereof. The seal device  19  is formed at one extremity with a mounting cuff  31  received in tight fit relationship over the tube  11  and adhered thereto by a high temperature bond. In the preferred embodiment, the cuff  31  is configured at its one end with a radially outwardly projecting retainer flange  35  and has formed in axially spaced relationship therealong radially outwardly opening latching and unlatching grooves  37  and  39 , respectively.  
         [0017]     Such seal device is configured in axial spaced relationship between the ends of the respective tubes  11  and  13  with a radially inwardly projecting spacer ring  41  sandwiched between the ends of such tubes. The seal device is further configured in its interior curved step  43  which abuts against a curved cylindrical skirt  44  of a flow restrictor ring, generally designated  45 , that projects radially inwardly to form a constricting orifice of a selected configuration within the interior of the space between the juncture of the tubes  11  and  13 .  
         [0018]     The seal device  17  is further formed with the cowling  19  projecting distally beyond the flow restrictor ring  45  and is formed with a radially inwardly opening annular relief notch  47  to be registered over, and clear the bead  21  when the seal is in its sealing position. The compressible sealing ring is then formed at its open end of the cowling with the ring  25  defining one annular side of such relief notch.  
         [0019]     The seal device  17  will typically be constructed with its wall and the sealing ring  25  of sufficient radial thickness to cause the open extremity of the cowling to be, when fitted on the tube  11  flared radially outwardly to an exterior radius larger than that of the inside diameter of the open end of the shell. The inner diameter of the shell collar is of a smaller diameter such that when fitted over the end of such outwardly splayed cowling  19  will cause such collar to constrain the free end of the cowling radially inwardly to press such ring against the tube  11  to form a fluid tight seal. The sealing ring may be formed in its free end with a frusto conical distally facing cam surface  36 .  
         [0020]     The shell  17  is generally cylindrically shaped and is formed on its mounting end with a radially inturned flange  51  which abuts against the annular shoulder formed by the radial surface of the retainer flange  35  at one end of the seal device  17 , the shell being of sufficient length to substantially encompass the outer surface of the seal. The shell  17  is formed medially with a radially inwardly pressed latch ring  55  which is configured to selectively engage one or the other of the respective latch or unlatch grooves  37  and  39 , respectively. The collar  27  is formed at its distal extremity with a radially outwardly turned reinforcing flange  59 .  
         [0021]     The seal device  17  is constructed of stretchable materials and is so arranged and configured that it will accommodate stretching of the sealing ring  25  to ride over the bead  21  and will afford sufficient radial body to such sealing ring  25  to provide for compression thereof when the shell is shifted to its latching position shown in  FIG. 4 . The magnitude of compression will be tailored to the particular applications but, in one preferred embodiment, for smaller diameter pipes on the order of 2½-3′. Preferably, the seal device is constructed of fire resistant material resistant to temperatures on the order of about 450° F. but at least up to 250° F. and may consist of silicon rubber. In the preferred embodiment, the seal device is constructed of a silicon rubber having a Durometer hardness of  45  on the A scale capable of withstanding stretch of an elongation of 400% or more without failure. One material found to be satisfactory for this application is formulation number 945-C-3375 available from Kirkhill Rubber 300 East Cypress, P.O. Box 1270, Brea, Calif. 92822.  
         [0022]     The shell is also preferably constructed of fire resistant material and may be of a composite pre-pregnated fiberglass cloth and an uncured phenolic resin. A material that has proven satisfactory for this application is a multiple ply fiberglass cloth available under the product designation CYOCM 3265 available from Cytec Industries, Inc., Five Garret, Mountain Plaza, West Patterson, N.J. 07424.  
         [0023]     In operation, it will be appreciated that the duct sections or tubes  11  and  13  may be installed in the aircraft or other airframe vehicle and may be flexible and formed with custom turns and bends to fit the path through the vehicle. The bead  21  will be formed in the tube  13  during manufacture. In the event a flow restriction orifice is to be incorporated, the flow restrictor  45  may be positioned within the cowling before the tube  13  is moved into position relative to the tube  11 . It will be appreciated that the cowling collar  31  of the seal device is mounted or otherwise adhered to the tube  11  as by a silicon adhesive. An adhesive satisfactory for this application is product number  732  available from Dow Corning.  
         [0024]     In practice, the seal device is constructed by high pressure molding to form the configuration desired for the grooves  37  and  39 , the relief groove  47 , spacer rib  41  and sealing ring  25 . In assembly, if desirable, the shell may be fitted over the seal prior to the time the mounting sleeve is adhered to the tube  11  or may be telescoped there over after such adherence it being appreciated that there is sufficient compression in the body of the seal device to allow for sufficient compression so the rib  55  can ride along the exterior surface of such seal as it rides between such grooves  37  and  39  with shifting of the shell. In any event, when the tubes  11  and l 3  are to be coupled together the shell may be shifted to its unlatched position shown in  FIG. 5  with the latching rib  55  engaged in the detent formed by the groove  37  and the collar  27  free of the cowling. The tubes  11  and  13  may then be axially shifted together causing the frusto conically shaped caming surface  36  to ride up over the rib  21  allowing such bead to stretch the ring  25  to pass it over the bead and assume the position shown in  FIG. 5  engaged behind the bead. The sealing ring  25  will serve to, when riding on the wall of the tube  13 , flare the free end of the cowling radially outwardly to a diameter larger than the inside diameter o the sleeve collar ( FIG. 5 ). Thereafter, the shell will be slid to the latching position shown in  FIG. 4  shifting the constraining collar over the bead  21  to compress the sealing ring  25  radially inwardly against the exterior surface of the tube  13  to thereby form a positive seal.  
         [0025]     Thereafter, the passage within the tubes may be loaded with, for instance, pressurized fluid or even a partial vacuum and the combination of shell and seal will resist leakage. To this end, it will be appreciated should the tubes be pressurized, the fluid seeking to seep out under the sealing ring  25  will be resisted by the compression thereof. Similarly, in the event of a partial vacuum within the tubes, air seeking to seep under the sealing seep between the sealing ring  25  and outer surface of the tube  13  will be resisted by the compressive seal thereof.  
         [0026]     Should it become necessary to uncouple the tubes, the workman may grasp the shell and slide it rearwardly on the tube  11  causing the rib  55  to disengage from the groove  37  allowing such sleeve to be drawn rearwardly to disengage the free end of the collar  27  from registration with the sealing ring to free the open end of such collar to expand and pass over the bead as the tubes are drawn apart.  
         [0027]     It has been determined that the quick disconnect disclosed in the preferred embodiment will withstand relatively high pressures and temperatures, resisting temperatures of over 250° F. for extended periods of time and have been determined sufficient to pass FAA regulation FAR 25.856 for flammability.  
         [0028]     The task of connecting a disconnecting quick disconnect is relatively straightforward and requires only minimal space for maneuvering by the workman to achieve the sealing or unsealing function. This then allows for packaging of adjacent components and closer spaced relationship within the airframe and affords both efficient coupling and uncoupling of the connector.