Patent Publication Number: US-2004045627-A1

Title: Fuel dispensing nozzle having a lever trigger biased by a torsion wire coil spring

Description:
BACKGROUND OF THE INVENTION  
       [0001] This invention relates to a vapor assisted fuel dispensing nozzle of the general type disclosed in U.S. Pat. No. 5,832,970. In such a nozzle, a nozzle body defines a fuel supply passage, and a normally closed main control valve is actuated by a lever pivotally supported by the nozzle body for controlling the supply of fuel through the fuel supply passage. The lever is protected by a guard member secured to the body, and the actuating lever carries a latch or trigger member which is pivotally supported by a cross pin. The trigger member has an outer end portion adapted to engage a catch or stop member supported by the guard member, and a spring member biases the trigger member towards the lever. Actuation of the trigger member functions to hold the actuating lever and the fuel supply valve in their open positions until the nozzle spout detects the presence of fuel and automatically lifts the lever to release the trigger member and permit the lever and fuel supply valve to return to their normally closed positions.  
       [0002] As disclosed in the above &#39;970 patent, the latch or trigger member  78  is biased against a stop on the actuating lever  60  by a conventional sheet metal leaf spring  84  which extends above the pivot pin for the latch or trigger member  78 . Such a sheet metal leaf spring has been used for over 30 years and is disclosed, for example, in U.S. Pat. No. 3,653,415, No. 3,817,285, No. 4,022,235 and No. 5,289,856. After a fuel dispensing nozzle has been used for filling fuel tanks with an automatic shut-off of the valve actuating lever for approximately 100,000 times, it has been found that the leaf spring fatigues and fails by weakening and/or breaking. This requires that the nozzle be serviced by removing the trigger member and replacing the leaf spring. Frequently, the leaf spring is one of the first components to fail, which usually requires that the fuel dispensing nozzle be removed from the fuel supply hose and shipped back to the nozzle manufacturer or rebuilder to replace the leaf spring.  
       SUMMARY OF THE INVENTION  
       [0003] The present invention is directed to a fuel dispensing nozzle of the type described above and which incorporates an improvement for significantly extending the service life of the nozzle before requiring replacement or rebuilding. The improvement comprises replacing the conventional leaf spring for actuating the latch or trigger member with a formed wire coil torsion spring having a plurality of turns mounted on the pivot pin for the latch or trigger member. The wire coil spring has opposite end portions which engage the valve actuating lever and the trigger member.  
       [0004] Other features and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
     [0005]FIG. 1 is a side elevational view of a vacuum assist vapor recovery fuel dispensing nozzle constructed in accordance with the invention;  
     [0006]FIG. 2 is a side elevational view of the actuating lever assembly with a portion broken away to show the use of a wire coil torsion spring in accordance with the invention; and  
     [0007]FIG. 3 is an exploded perspective view of the assembly shown in FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0008]FIG. 1 illustrates a vacuum assist vapor recovery fuel dispensing nozzle  10  having the general construction of the dispensing nozzle disclosed in above-mentioned U.S. Pat. No. 5,832,970, the disclosure of which is incorporated by reference. The nozzle  10  includes a die cast aluminum body  12  having an integral internally threaded fitting  14  for receiving a mating fitting on a coaxial flexible rubber hose (not shown) defining a fluid supply passage and a vapor return passage connected to a vacuum source. The nozzle  10  includes a normally closed fuel control valve (not shown) which is actuated to an open position by squeezing a hand actuated lever  16  enclosed within a lever protector housing  18 .  
     [0009] The nozzle body  12  supports a spout assembly  20  which projects from a forward portion  22  of the nozzle body  12 . The spout assembly  20  includes an outer spout tube  24  constructed of aluminum tubing and having an inner end portion threaded into an anti-rotation ring or fitting secured to the body end portion  22  by a retaining nut  26 . A resilient O-ring forms a fluid-tight seal between the fitting and the body portion  22 , and a helically wound spring wire  31  surrounds the spout tube  24 , in a conventional manner. The aluminum outer spout tube  24  includes an integral cylindrical forward end portion  34  having a thinner wall thickness and which surrounds a stainless steel vapor recovery extension spout tube  36  having circumferentially spaced and axially extending slots or grooves  38 .  
     [0010] Referring to FIGS. 2 &amp; 3, the actuating lever  16  carries a latch or trigger member  45  which is pivotally supported by the lever  16  by a cross pin  47  and moves between a normal position (FIG. 2) and a downwardly projecting inclined position (not shown) where the outer end of the trigger member  45  selectively engages one of a series of projections  51  of a stop member  52  mounted within the lever protector housing  18 . The pin  47  also pivotally supports a channel-like link member  53  which connects the lever  16  to its pivot pin supported by an automatic lever release mechanism.  
     [0011] In accordance with the present invention, the trigger member  45  is biased or urged counter-clockwise (FIG. 2) against a stop surface  54  on the lever  16  by a torsion wire coil spring  55  having a plurality of at least five helical turns  56  (FIG. 3) surrounding the pivot pin  47  for the trigger member  45 . The torsion wire coil spring  55  has one projecting end portion  58  which engages and presses agains the trigger member  45  and an opposite end portion  62  which engages a receiving surface  64  formed on the actuating lever  16 .  
     [0012] It has been found that the torsion wire coil spring  55  significantly increases the useful service life of the pivotal trigger member  45  and thereby significantly increases the service life of the nozzle  10  with an automatic fill shut-off mechanism. More specifically, extensive testing of the trigger member  45  during its use for holding the main fuel control valve in its open position has resulted in over one million pivotal actuations of the trigger member  45  without any failure of the wire coil spring  55 . This compares with approximately one hundred thousand actuations of a trigger member biased by a conventional leaf spring when the leaf spring failed. Thus by simply replacing a conventional leaf spring with the torsion wire coil spring  55 , the service life of the dispensing nozzle  10  is significantly increased. As a result, the cost for servicing the nozzle  10  is significantly decreased.  
     [0013] While the form of nozzle assembly herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of nozzle assembly, and that changes may be made therein without departing from the scope and spirit of the invention as defined in the appended claims.