Ratcheted fuel cap

Abstract

A fuel tank cap that is engageable with a neck of a fuel tank. The fuel tank cap includes a cap shell that has a cover portion and a substantially cylindrical wall extending from the cover portion to define a substantially cylindrical chamber. An arm extends from the cover portion toward the fuel tank. An inner shell is at least partially disposed within the cylindrical chamber. The inner shell includes an engagement portion that is engageable with the neck and a protrusion that is engageable with the arm to selectively couple the cap shell and the inner shell for rotation in unison.

1 . A fuel tank cap engageable with a neck of a fuel tank, the fuel tank having a fuel chamber adapted to contain fuel, the fuel tank cap comprising: 
 a cap shell including a cover portion and a substantially cylindrical wall extending from the cover portion to at least partially define a substantially cylindrical chamber;    an arm extending from the cover portion toward the fuel chamber of the fuel tank when the fuel tank cap is installed on the fuel tank; and    an inner shell at least partially disposed within the cylindrical chamber, the inner shell including an engagement portion that is engageable with the neck and a protrusion engageable with the arm to selectively couple the cap shell and the inner shell for rotation in unison.    
   
   
       2 . The fuel tank cap of  claim 1 , wherein the cap shell includes a lobe that defines a lobe space, the lobe space disposed near the arm.  
   
   
       3 . The fuel tank cap of  claim 2 , wherein the arm is substantially disposed outside of the lobe space when the cap shell and inner shell are coupled for rotation and the arm is deflected at least partially into the lobe space to decouple the cap shell and the inner shell.  
   
   
       4 . The fuel tank cap of  claim 2 , wherein the arm is one of a plurality of arms and the lobe is one of a plurality of lobes, each lobe defining a lobe space and each arm disposed near one of the lobe spaces.  
   
   
       5 . The fuel tank cap of  claim 4 , wherein each of the plurality of arms is deflectable into the lobe space to decouple the cap shell and the inner shell such that the cap shell is rotatable relative to the inner shell  
   
   
       6 . The fuel tank cap of  claim 1 , wherein the engagement portion includes threads.  
   
   
       7 . The fuel tank cap of  claim 1 , wherein the protrusion includes a first side engageable with the arm to couple the cap shell and the inner shell for rotation in unison.  
   
   
       8 . The fuel tank cap of  claim 7 , wherein the first side is substantially planar.  
   
   
       9 . The fuel tank cap of  claim 7 , wherein the protrusion includes a second side engageable with the arm to couple the cap shell and the inner shell for rotation in unison when a torque applied to the cap shell is at or below an engaged value.  
   
   
       10 . The fuel tank cap of  claim 9 , wherein the second side of the protrusion engages and displaces the arm to allow the cap shell to rotate relative to the inner shell when the torque value exceeds the engaged value.  
   
   
       11 . The fuel tank cap of  claim 9 , wherein the second side is not planar.  
   
   
       12 . The fuel tank cap of  claim 1 , wherein the cap shell includes one of a bead and a recess that extends around the cylindrical wall, and the inner shell includes the other of the bead and recess, the bead engaged with the recess to rotationally couple the cap shell and the inner shell.  
   
   
       13 . The fuel tank cap of  claim 1 , wherein the arm is connected to the cover portion such that the arm is supported in a cantilever fashion.  
   
   
       14 . A fuel tank cap engageable with a neck that defines a neck axis, the fuel tank cap comprising: 
 an inner shell rotatable relative to the neck to move between an engaged position and a disengaged position;    a cap shell including an arm that defines an arm axis; and    a protrusion extending from the inner shell, the protrusion cooperating with the arm to couple the inner shell and the cap shell for rotation in unison from the disengaged position to the engaged position, the protrusion displacing the arm such that the cap shell rotates independent of the inner shell when rotated beyond the engaged position, the protrusion engaged with the arm to couple the inner shell and the cap shell for rotation in unison from the engaged position to the disengaged position.    
   
   
       15 . The fuel tank cap of  claim 14 , wherein the arm axis is substantially parallel to the neck axis.  
   
   
       16 . The fuel tank cap of  claim 14 , wherein the inner shell includes a threaded portion and the neck includes a threaded portion, the inner shell threadably engageable with the neck.  
   
   
       17 . The fuel tank cap of  claim 14 , wherein the cap shell includes a cover portion that is substantially normal to the neck axis and wherein the arm extends in a cantilever fashion from the cover portion.  
   
   
       18 . The fuel tank cap of  claim 14 , wherein the cap shell includes a lobe defining a lobe space, and wherein a portion of the arm is movable into the lobe space.  
   
   
       19 . The fuel tank cap of  claim 18 , wherein the arm is one of a plurality of arms, and the lobe is one of a plurality of lobes, each lobe defining a lobe space, at least a portion of each arm movable into one of the lobe spaces.  
   
   
       20 . The fuel tank cap of  claim 19 , wherein the protrusion is one of a plurality of protrusions and wherein the number of protrusions is substantially equal to the number of arms.  
   
   
       21 . The fuel tank cap of  claim 14 , wherein the arm Includes a first angled surface and the protrusion includes an angled surface engageable with the first angled surface to couple the cap shell and the inner shell for rotation.  
   
   
       22 . The fuel tank cap of  claim 21 , wherein the first angled surface and the angled surface are angled such that when engaged, rotation of the cap shell produces a force that biases the arm toward the inner shell.  
   
   
       23 . The fuel tank cap of  claim 21 , wherein the arm includes a second angled surface and the protrusion includes an arcuate surface engageable with the second angled surface to couple the cap shell and the inner shell for rotation.  
   
   
       24 . The fuel tank cap of  claim 23 , wherein the second angled surface and the arcuate surface are such that when engaged, rotation of the cap shell produces a force that biases at least a portion of the arm away from the inner shell.  
   
   
       25 . A fuel tank cap engageable with a neck of a fuel tank that defines a neck axis, the fuel tank also having a fuel chamber adapted to contain fuel, the fuel tank cap comprising: 
 a cap shell including a cover portion that is substantially normal to the neck axis and a substantially cylindrical wall extending from the cover portion to at least partially define a substantially cylindrical chamber;    an arm extending from the cover portion toward the fuel chamber of the fuel tank;    an inner shell at least partially disposed within the cylindrical chamber and engageable with the neck, the inner shell rotatable relative to the neck to move between a disengaged position and an engaged position; and    a protrusion having a first side and a second side, the first side engageable with the arm to couple the cap shell and inner shell for rotation from the engaged position to the disengaged position, the second side engageable with the arm to couple the cap shell and inner shell for rotation from the disengaged position to the engaged position when a rotational torque is below an engaged value, the second side operable to displace the arm such that the cap shell rotates independent of the inner shell when the rotational torque exceeds the engaged value.    
   
   
       26 . The fuel tank cap of  claim 25 , wherein the inner shell includes a threaded portion and the neck includes a threaded portion, the inner shell threadably engageable with the neck.  
   
   
       27 . The fuel tank cap of  claim 25 , wherein the cap shell includes a lobe defining a lobe space, and wherein a portion of the arm is movable into the lobe space.  
   
   
       28 . The fuel tank cap of  claim 27 , wherein the arm is one of a plurality of arms, and the lobe is one of a plurality of lobes, each lobe defining a lobe space, at least a portion of each arm movable into one of the lobe spaces.  
   
   
       29 . The fuel tank cap of  claim 28 , wherein the protrusion is one of a plurality of protrusions, the quantity of protrusions being substantially equal to the quantity of arms.  
   
   
       30 . The fuel tank cap of  claim 25 , wherein the arm includes a first angled surface and the protrusion includes an angled surface engageable with the first angled surface to couple the cap shell and the inner shell for rotation.  
   
   
       31 . The fuel tank cap of  claim 30 , wherein the first angled surface and the angled surface are angled such that when engaged, rotation of the cap shell produces a force that biases the arm toward the inner shell.  
   
   
       32 . The fuel tank cap of  claim 30 , wherein the arm includes a second angled surface and the protrusion includes an arcuate surface engageable with the second angled surface to couple the cap shell and the inner shell for rotation.  
   
   
       33 . The fuel tank cap of  claim 32 , wherein the second angled surface and the arcuate surface are arranged such that when engaged, rotation of the cap shell produces a force that biases the arm away from the inner shell.