Abstract:
A tubular elbow member for connecting an angle cock and an intermediate hose on a pneumatic line of a railroad car. The tubular elbow has a threaded male end and a threaded female end each connected via a tubular portion having an inside radius of curvature of 2.5 to 3 times the inside diameter of the elbow.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to an elbow connector for a pneumatic line on railroad cars.  
           [0002]    More particularly, the invention relates to an elbow connector for connecting an angle cock and an intermediate hose on a railroad car. The elbow connector of the present invention is shaped to provide enhanced flow and lower resistance than the presently used two 45° street elbows or a 90° lower radius (less than two times the inside diameter) elbow fitting. The invention requires no modification or adjustment to existing hose assemblies as it fits in the same envelope as conventional fittings.  
           [0003]    Railroad cars having pneumatic brake systems use a brake pipe and flexible air hoses on each car to extend the pneumatic system the length of the train. The flexible hoses are used for spanning between separate adjacent railroad cars. Typically, the brake pipe extends from the front to the back of a railroad car and terminates in a cut-off valve, known in the art as an angle cock. Recent improvements in railroad car couplings have placed a barrier adjacent the angle cock such that the connection from the angle cock must change the direction of the pneumatic piping away from the barrier. One prior art solution was to connect an elbow having a low radius of curvature (see FIGS. 1 and 2) to the angle cock to produce a 90° turn as shown in FIG. 3. Another solution was to connect a pair of 45° steel elbows to the angle cock (see FIG. 3). However, the use of the 90° elbow in FIGS. 1 and 2 and the two 45° steel elbows suffer from numerous disadvantages, e.g., poor flow rates and poor flow conditions. The present invention is designed to overcome these disadvantages and provide an improved coupling arrangement with the angle cock.  
           [0004]    Other examples of 90° connectors in rail cars are shown in U.S. Pat. Nos. 2,369,888, 2,000,157, and 741,051.  
           [0005]    The prior art connector shown in FIGS. 1 and 2 is sold with a hose connected to the male end of the connector. The combination hose and connector is known as the M-618 hose fitting.  
           [0006]    The above three U.S. patent disclosures and the M-618 hose fitting do not disclose an elbow connector having male and female ends connected by a portion having a large radius of curvature as described hereinafter.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention overcomes the above disadvantages by providing an elbow connector of an improved design for connecting an angle cock to a pneumatic hose on a railroad car. The improved elbow connector has a male threaded end, a female threaded end and a curved tubular portion connecting the male and female ends. The curved tubular portion has a radius of curvature of 2.5 to 3 times the inside diameter of the tubular portion.  
           [0008]    Additionally, the present invention advantageously provides an elbow which curves 90°.  
           [0009]    Other improvements provide a combination having further advantages. Such improvements include: an exterior hex nut surface which is the same size as a common wrench used for air end hose nipple hex nuts; a yellow chromate and zinc plating; standard NPT threads; and the use of ductile or malleable iron to form the elbow as a monolithic structure.  
           [0010]    Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a side view of a prior art elbow connector.  
         [0012]    [0012]FIG. 2 shows an end view of the prior art connector of FIG. 1.  
         [0013]    [0013]FIG. 3 shows another prior art connector for joining an angle cock and an air hose.  
         [0014]    [0014]FIG. 4 shows the elbow connector of the present invention connecting an angle cock and an air hose.  
         [0015]    [0015]FIG. 5 shows a cut-away view of the elbow connector along line V-V of FIG. 6.  
         [0016]    [0016]FIG. 6 shows an end view of the elbow connector of the invention.  
         [0017]    [0017]FIG. 7 shows a plan view of the elbow connector of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    A prior art elbow connector  10  for joining an angle cock and an air hose is shown in FIGS. 1 and 2. The connector  10  has an inside diameter of 1.26″ and a radius of curvature R of two inches (2″). The connector  10  has a male threaded end  12 , a hex nut surface  14 , a curved portion  16  and a female end  18  having internal threads (not shown). The combination of the connector  10  of FIG. 1 and a hose is known in the art as the M-618 hose fitting.  
         [0019]    Another prior art connection between an angle cock and an air hose is seen in FIG. 3. A brake pipe  40  is shown connected to an angle cock  42  (cut-off valve) which is connected to one end of an air hose  44  via a pair of 45° steel elbows  20 . The other end of the hose  44  is supported by connector  46  to shank coupler bracket  48 . A second hose  50  extends from the first hose  44  and ends in a connector  52  known in the art as a glad hand.  
         [0020]    [0020]FIG. 4 shows the preferred embodiment wherein a 90° sweep elbow connector  30  of the present invention replaces the elbow connector  10  or the two 45° steel elbows  20 . Elbow connector  30  is a monolithic member made of, for example, ductile or malleable iron and is designed to be coupled to a standard angle cock on railroad cars. An example of a suitable material is Schedule 80 Ductile Iron. The elbow connector  30  is designed with a large radius to reduce flow losses and has other features that improve its function and ease of use. For example, the connector weighs only about two and one-half (2 ½) pounds and can be easily manipulated.  
         [0021]    As seen in FIG. 5 the 90° sweep elbow connector  30  has a female threaded end  38  and a male threaded end  32 . The threads on the ends conform to NPT (National Pipe Thread) standards and enable the connector  30  to be screwed into any angle cock. The inside diameter (ID) of connector  30  is typically in the range of 1 to 2 inches. 1.278″ is an example of an ID being used. The radius of curvature R (see FIG. 7) of the connector  30  is large, a minimum of about two and one-half to three times the ID. The large radius of curvature is an improvement over the prior art and enables connector  30  to provide a change in direction of the air flow while also providing an increased air flow due to lower resistance.  
         [0022]    [0022]FIG. 7 shows the elbow connector  30  with the male threaded end having a polygonal surface  34 , for example, a hex nut for providing positive wrench engagement making installation quick and simple. The polygonal surface  34  shown is the same size as a common wrench used for air end hose nipple hex nuts. As shown, the large radius of curvature R provides reduced flow losses in the curved portion over the two 45° steel elbows  20  shown in FIG. 3 or the elbow connector  10  shown in FIGS. 1 and 2. A yellow chromate and zinc plating (not shown) may be provided on the surface of the elbow connector  30  to protect it from corrosion.  
         [0023]    Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.