Lockable pressure relief fuel cap

Abstract

A lockable pressure-release fuel cap is provided to close a filler neck. An actuation system within the fuel cap is operable to enable a user to vent fuel vapor pressure in the filler neck in response to rotation of a key in a lock unit included in the fuel cap prior to removal of the fuel cap from the filler neck.

I claim: 
     
       1. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for threadably engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means about an axis of rotation,   vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere,   lock means coupled to the shell means and movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell means and the closure means for movement of the closure means in the cap-removing direction, and   means for actuating the vent means in response to movement of the lock means from the locked position to the unlocked position, the actuating means being supported for reciprocating movement along the axis of rotation during movement of the lock means between the locked position and the unlocked position.   
     
     
       2. The cap of claim 1, wherein the lock means includes a cam and the actuating means includes a plunger and a cam follower positioned on the plunger to engage the cam and move the plunger along the axis of rotation during movement of the lock means to the unlocked position. 
     
     
       3. The cap of claim 2, wherein the lock means includes a lock mechanism and a throw member coupled to the lock mechanism and configured to define the cam. 
     
     
       4. The cap of claim 2, wherein the cam follower is an annular ramp positioned to wind around the axis of rotation. 
     
     
       5. The cap of claim 4, wherein the lock means further includes a lock mechanism formed to include a keyway and a key-actuated throw member, the key-actuated throw member is configured to define the cam, and the key-actuated throw member is coupled to the lock mechanism to rotate relative to the lock mechanism in response to turning a key in the keyway to urge the cam defined by the throw member against the cam follower to move the plunger as the throw member rotates relative to the lock mechanism. 
     
     
       6. The cap of claim 1, wherein the actuating means includes an elongated neck positioned to lie in the closure means and to move along the axis of rotation of the closure means in response to movement of the lock means to the unlocked position. 
     
     
       7. The cap of claim 6, wherein the vent means includes a vacuum-relief valve and the elongated neck is moved along the axis of rotation to engage the vacuum-relief valve in response to movement of the lock means to the unlocked position. 
     
     
       8. The cap of claim 1, wherein the closure means is formed to include an interior region and the lock means includes a lock mechanism and a throw member coupled to the lock mechanism and positioned to extend into the interior region of the closure means. 
     
     
       9. The cap of claim 8, wherein the actuating means includes a plunger having an annular ramp positioned to wind around the axis of rotation and to engage the throw member during movement of the lock means to the unlocked position and a neck positioned to move along the axis of rotation during movement of the lock means to the unlocked position and the throw member is positioned to cam the annular ramp to move the neck along the axis of rotation to engage and actuate the vent means in response to movement of the lock means to the unlocked position. 
     
     
       10. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means,   vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere,   lock means coupled to the shell means and movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell means and the closure means for movement of the closure means in the cap-removing direction,   means for actuating the vent means in response to movement of the lock means from the locked position to the unlocked position,   race means for engaging the closure member, and   drive hub means coupled to the shell means for engaging the race means to provide a cap-installing driving connection between the shell means and the closure means for movement of the closure means in a cap-installing direction, the drive hub means further including means for disengaging the cap-installing driving connection in response to movement of the shell means in a cap-removing direction.   
     
     
       11. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means,   vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere,   lock means coupled to the shell means and movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell means and the closure means for movement of the closure means in the cap-removing direction, and   means for actuating the vent means in response to movement of the lock means from the locked position to the unlocked position, the lock means including a cam, the actuating means including plunger means for actuating the vent means, and the plunger means having cam follower means for urging the plunger means to a vent means-actuating position in response to movement of the cam during movement of the lock means to the unlocked position.   
     
     
       12. The cap of claim 11, further comprising removal hub means for engaging the closure means, and wherein the plunger means further includes means for engaging the removal hub means to establish the cap-removing driving connection. 
     
     
       13. The cap of claim 11, further comprising lock cylinder housing means for coupling the lock means to the shell means, and wherein the plunger means includes finger means for engaging the lock cylinder housing means and the finger means is movable from an engaging position to a driving connection-maintaining position. 
     
     
       14. The cap of claim 13, wherein the finger means is movable from the engaging position to the driving connection-maintaining position in response to movement of the lock means to the unlocked position. 
     
     
       15. The cap of claim 13, wherein the finger means is movable from the driving connection-maintaining position to the engaging position in response to movement of the shell means relative to the closure means in a cap-installing direction. 
     
     
       16. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for threadably engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means,   lock means coupled to the shell means and movable between a locked position and an unlocked position for selectively locking and unlocking the fuel cap,   vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere, and   coupling means for providing a cap-removing driving connection between the shell means and the closure means in response to movement of the lock means from the locked position to the unlocked position for movement of the closure means in a cap-removing direction, the coupling means including plunger means for actuating the vent means in response to movement of the lock means to the unlocked position.   
     
     
       17. The cap of claim 16, wherein the coupling means further includes removal hub means for engaging the closure means and the plunger means includes engagement means for drivingly connecting the plunger means to the removal hub means in response to the movement of the lock means to the unlocked position. 
     
     
       18. The cap of claim 17, wherein the engagement means includes a plurality of first drive teeth formed on the plunger means, the removal hub means includes a plurality of second drive teeth, and the plunger means and the removal hub means are positioned to orient the first drive teeth and complementary relationship with the second drive teeth to establish the cap-removing driving connection between the closure means and the shell means. 
     
     
       19. The cap of claim 17, wherein the plunger means includes means for disabling the cap-removing driving connection in response to movement of the shell means relative to the closure means in a cap-installing direction. 
     
     
       20. The cap of claim 19, wherein the disabling means includes first ramping surfaces formed on the plunger means and second ramping surfaces formed on the removal hub means, and the first and second ramping surfaces are complementary to each other and configured to ramp against each other in response to movement of the shell means relative to the closure means in the cap-installing direction. 
     
     
       21. The cap of claim 16, wherein the coupling means further includes a removal hub rotationally coupled to the closure means, the plunger means actuating the vent means and engaging the removal hub means to rotationally lock the shell means to the closure means for rotation of the closure means in a cap-removing direction. 
     
     
       22. The cap of claim 21, wherein the actuating and engaging occur simultaneously in response to movement of the lock means from the locked position to the unlocked position. 
     
     
       23. The cap of claim 16, wherein the lock means includes a cam and the plunger means includes a cam follower positioned to engage the cam during movement of the lock means to the unlocked position. 
     
     
       24. The cap of claim 23, wherein the lock means includes a lock mechanism and a throw member coupled to the lock mechanism and configured to define the cam. 
     
     
       25. The cap of claim 23, wherein the cam follower is an annular ramp. 
     
     
       26. The cap of claim 23, wherein the lock means further includes a lock mechanism formed to include a keyway and a key-actuated throw member, the key-actuated throw member is configured to define the cam, and the key-actuated throw member is coupled to the lock mechanism to rotate relative to the lock mechanism in response to turning a key in the keyway to urge the cam defined by the throw member against the cam follower to move the plunger means as the throw member rotates relative to the lock mechanism. 
     
     
       27. The cap of claim 16, wherein the closure means is rotatable about an axis of rotation and the plunger means includes a neck positioned to move along the axis of rotation of the closure means in response to movement of the lock means to the unlocked position. 
     
     
       28. The cap of claim 27, wherein the vent means includes a vacuum-relief valve and the neck is moved along the axis of rotation to engage the vacuum-relief valve in response to movement of the lock means to the unlocked position. 
     
     
       29. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means rotatably engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means,   lock means coupled to the shell means for selectively locking and unlocking the fuel cap, the lock means being movable between a locked position and an unlocked position,   coupling means for establishing a cap-removing driving connection between the shell means and the closure means in response to movement of the lock means to the unlocked position for movement of the closure means in a cap-removing direction, and   uncoupling means for automatically disabling the cap-removing driving connection in response to movement of the shell means relative to the closure means in the cap-installing direction when the lock means is in the locked position.   
     
     
       30. The cap of claim 29, further comprising vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere through the closure means, and wherein the coupling means includes means for opening the vent means in response to movement of the lock means to the unlocked position. 
     
     
       31. The cap of claim 30, wherein the uncoupling means includes means for moving the opening means from a vent means-opening position to a vent means-closing position in response to movement of the shell means relative to the closure means in the cap-installing direction. 
     
     
       32. The cap of claim 30, wherein the lock means includes a cam and the opening means includes a cam follower positioned to engage the cam during movement of the lock means to the unlocked position. 
     
     
       33. The cap of claim 32, wherein the lock means further includes a lock mechanism and a throw member coupled to the lock mechanism and configured to define the cam. 
     
     
       34. The cap of claim 30, wherein the closure means is rotatable about an axis of rotation and the plunger means includes a neck positioned to move along the axis of rotation of the closure means in response to movement of the lock means to the unlocked position. 
     
     
       35. The cap of claim 34 wherein the vent means includes a vacuum-relief valve and the neck is moved along the axis of rotation to engage the vacuum-relief valve in response to movement of the lock means to the unlocked position. 
     
     
       36. The cap of claim 29, wherein the coupling means includes a plunger having finger means movable between an engaged position and a driving connection-maintaining position, the finger means moving to the driving connection-maintaining position in response to movement of the lock means to the unlocked position and moving to the engaged position in response to movement of the shell means relative to the closure means in the cap-installing direction. 
     
     
       37. The cap of claim 29, wherein the coupling means includes a plunger rotationally locked to the shell means and a removal hub rotationally locked to the closure. 
     
     
       38. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure member,   lock means coupled to the shell means for selectively locking and unlocking the fuel cap,   removal hub means for engaging the closure member, and   plunger means for engaging the removal hub means; the lock means, removable hub means, and plunger means cooperating to establish a cap-removing driving connection between the shell means and the closure means in response to movement of the lock means to the unlocked position for movement of the closure means in a cap-removing direction.   
     
     
       39. The cap of claim 38, wherein the plunger means includes means for automatically disengaging the cap-removing driving connection in response to movement of the shell means relative to the closure means in a cap-installing direction. 
     
     
       40. The cap of claim 39, wherein the plunger means is rotationally locked to the shell means and the removal hub means is rotationally locked to the closure means and the plunger means includes ramp means for engaging the lock means to drive the plunger means into engagement with the removal hub means in response to movement of the lock means to the unlocked position. 
     
     
       41. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for rotatably engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure member,   lock means coupled to the shell means and movable between a locked position and an unlocked position for selectively locking and unlocking the fuel cap,   first means for providing a uni-directional cap-installing driving connection between the shell means and the closure means, the cap-installing driving connection being bypassed in response to movement of the shell means relative to the closure means in the cap-removing direction, and   second means for providing a uni-directional cap-removing driving connection between the shell means and the closure means in response to movement of the lock means to the unlocked position, the cap-removing driving connection being disabled by movement of the shell means relative to the closure means in the cap-installing direction when the lock means is in the locked position.   
     
     
       42. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for rotatably engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means,   lock means coupled to the shell means and movable between a locked position and an unlocked position for selectively locking and unlocking the fuel cap,   vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere, and   coupling means for providing a cap-removing driving connection between the shell means and the closure means in response to movement of the lock means from the locked position to the unlocked position for movement of the closure means in a cap-removing direction, the coupling means including a plunger means for actuating the vent means in response to movement of the lock means to the unlocked position wherein the coupling means further includes removal hub means for engaging the closure means and the plunger means includes engagement means for drivingly connecting the plunger means to the removal hub means in response to the movement of the lock means to the unlocked position.   
     
     
       43. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising closure means for rotatably engaging and closing the filler neck, the closure means being movable relative to the filler neck between a removed position and an installed position,   shell means for providing a hand grip to permit manual rotation of the closure means,   lock means coupled to the shell means and movable between a locked position and an unlocked position for selectively locking and unlocking the fuel cap,   vent means for equalizing fuel vapor pressure between the filler neck and the atmosphere, and   coupling means for providing a cap-removing driving connection between the shell means and the closure means in response to movement of the lock means from the locked position to the unlocked position for movement of the closure means in a cap-removing direction, the coupling means including a plunger means for actuating the vent means in response to movement of the lock means to the unlocked position wherein the coupling means further includes removal hub means rotationally coupled to the closure means, the plunger means actuating the vent means and engaging the removal hub means to rotationally lock the shell means to the closure means for rotation of the closure means in a cap-removing direction. .Iadd.   
     
     
       44.  A fuel cap for closing a filler neck of a fuel tank, the cap comprising: a shell,   a closure including a shank portion adapted to engage and close the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position, the closure further including a radially outwardly extending flange coupled to the shank portion and arranged to lie within the shell,   a gasket coupled to the closure,   the shell positioned to lie adjacent to the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve positioned to lie within the closure, and   a metal retainer, the entire metal retainer being positioned to lie above the gasket and a portion of the metal retainer being positioned to lie below the radially outwardly extending flange..Iaddend..Iadd.45. The cap of claim 44, wherein the metal retainer is a ring and extends about the circumference of the shank portion of the closure..Iaddend..Iadd.46. The cap of claim 45, wherein the metal retainer is constructed of steel..Iaddend..Iadd.47. The cap of claim 46, wherein the shell is constructed of a plastics material..Iaddend..Iadd.48. The cap of claim 45, wherein the closure includes a flange extending outwardly from the shank portion, the shell includes a side wall extending around the flange and a tooth extending from the side wall, and the retainer is positioned to lie between the tooth of the shell and the flange of the closure..Iaddend..Iadd.49. The cap of claim 44, wherein the metal retainer includes a skirt positioned to lie adjacent to the   
     
     
        shell..Iaddend..Iadd.     The cap of claim 44, further comprising a lock mechanism coupled to the shell, the lock mechanism being movable from a locked position to an unlocked position and cooperating with the shell and the closure to establish a cap-removing driving connection therebetween for movement of the closure in a cap-removing direction..Iaddend..Iadd.51. The cap of claim 44, wherein the metal retainer includes a circumferential skirt arranged to engage the shell and an annular portion coupled to the circumferential skirt and positioned to lie between the closure and the circumferential skirt and engage the closure..Iaddend..Iadd.52. The cap of claim 51, wherein the closure further includes a radially outwardly extending flange coupled to the shank portion and the annular portion engages an underside of the radially outwardly extending 
     
     
        flange..Iaddend..Iadd.53.  A fuel cap for closing a filler neck of a fuel tank, the cap comprising a closure including a shank portion adapted to engage and close the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell positioned to lie adjacent to the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve positioned to lie within the closure,   a metal retainer coupled between the closure and shell,   a lock mechanism coupled to the shell, the lock mechanism being movable from a locked position to an unlocked position and cooperating with the shell and the closure to establish a cap-removing driving connection therebetween for movement of the closure in a cap-removing direction, and   a plunger formed to selectively engage the vent valve and a cam follower positioned on the plunger to engage the lock mechanism and move the plunger along the axis of rotation during movement of the lock to the unlocked position..Iaddend..Iadd.54. The cap of claim 53, wherein the lock mechanism includes a keyway and a key-actuated throw member formed for selective engagement with the cam follower to move the plunger as the throw member moves on the axis of rotation..Iaddend..Iadd.55. A fuel cap for closing a filler neck of a fuel tank, the cap comprising   a closure including a shank portion adapted to engage and close the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell positioned to lie adjacent the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve positioned to lie within the closure,   a metal retainer coupled between the closure and shell,   a lock mechanism coupled to the shell, the lock mechanism being movable from a locked position to an unlocked position and cooperating with the shell and the closure to establish a cap-removing driving connection therebetween for movement of the closure in a cap-removing direction, and   an elongated neck positioned to lie in the closure and configured for reciprocating movement along the axis of rotation to actuate the vent valve in response to movement of the lock mechanism from the locked position to the unlocked position..Iaddend..Iadd.56. The cap of claim 55, further comprising a removal hub engaging the closure and the neck to establish the cap-removing driving connection therebetween..Iaddend..Iadd.57. The cap of claim 56, wherein the elongated neck includes a plurality of first drive teeth and the removal hub includes a plurality of second drive teeth positioned to lie in a complementary relationship with the first drive teeth to establish the cap-removing driving connection between the closure and the shell..Iaddend..Iadd.58. The cap of claim 55, further comprising a lock-cylinder housing retaining the lock cylinder therein and the neck includes a finger configured for movement within the housing from an engaging position to a driving connection-maintaining position in response to movement of the lock mechanism to the unlocked position..Iaddend..Iadd.59. The cap of claim 58, wherein the finger is movable from the driving connection-maintaining position to the engaging position in response to movement of the shell relative to the closure in a cap-installing direction..Iaddend..Iadd.60. A fuel cap for closing a filler neck of a fuel tank, the cap comprising   a closure including a shank portion adapted to engage and close the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell positioned to lie adjacent the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve positioned to lie within the closure,   a metal retainer coupled between the closure and shell, and   a plunger formed for selective engagement with the vent valve..Iaddend..Iadd.61. The cap of claim 60, further comprising a lock mechanism coupled to the shell, the lock mechanism is movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell and the closure for movement of the closure in a cap-removing direction..Iaddend..Iadd.62. The cap of claim 61, further comprising a removal hub engaging the closure and the neck to establish the cap-removing driving connection therebetween..Iaddend..Iadd.63. The cap of claim 62, wherein the plunger includes a plurality of first drive teeth and the removal hub includes a plurality of second drive teeth positioned to lie in a complementary relationship with the first drive teeth to establish the cap-removing driving connection between the closure and the shell..Iaddend..Iadd.64. The cap of claim 63, wherein the plunger includes first ramping surfaces and the removal hub includes second ramping surfaces, and the first and second ramping surfaces are complementary to each other and configured to ramp against each other in response to movement of the shell relative to   
     
     
        the closure in the cap-installing direction..Iaddend..Iadd.65.  A fuel cap for closing a filler neck of a fuel tank, the cap comprising: a shell,   a closure including a shank portion adapted to engage and close the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position, the closure further including a radially outwardly extending flange coupled to the shank portion and arranged to lie within the shell,   a gasket coupled to the closure,   the shell positioned to lie adjacent to the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve positioned to lie within the closure, and   a metal member positioned to lie between the closure and shell, the metal member including an upper portion engaging the closure and a skirt extending away from the upper portion, the entire metal member being positioned to lie above the gasket and a portion of the metal member being positioned to lie below the radially outwardly extending flange..Iaddend..Iadd.66. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising:   a shell,   a closure adapted for engaging and closing the filler neck, the closure including a shank portion and being movable relative to the filler neck between a removed position and an installed position, the closure including a radially outwardly extending flange coupled to the shank portion and arranged to lie within the shell,   a gasket coupled to the closure,   the shell in communication with the closure to permit manual rotation of the closure about an axis of rotation,   a lock mechanism coupled to the shell, the lock mechanism being movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell and the closure for movement of the closure in a cap-removing direction, and   a metal retainer positioned to lie between the closure and shell, the metal retainer including an upper portion engaging the closure member and a skirt extending away from the upper portion, the entire metal retainer being positioned to lie above the gasket and a portion of the metal retainer being positioned to lie below the radially outwardly extending flange..Iaddend..Iadd.67. The cap of claim 66, further comprising a vent valve positioned to lie within the closure and configured to equalize fuel vapor pressure between the filler neck and the atmosphere..Iaddend..Iadd.68. The cap of claim 66, wherein the closure includes a shank portion and a flange that extends outwardly from the shank portion and the shell extends over the flange..Iaddend..Iadd.69. The cap of claim 68, wherein the metal retainer extends about the circumference of the shank portion of the closure..Iaddend..Iadd.70. The cap of claim 68, wherein the side wall of the shell includes a tooth extending therefrom and the retainer is positioned to lie between the tooth and the flange of the closure..Iaddend..Iadd.71. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising   a closure adapted for engaging and closing the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell in communication with the closure to permit manual rotation of the closure about an axis of rotation,   a lock mechanism coupled to the shell, the lock mechanism being movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell and the closure for movement of the closure in a cap-removing direction,   a metal retainer coupled between the closure and shell,   a vent valve positioned to lie within the closure and configured to equalize fuel vapor pressure between the filler neck and the atmosphere, and   a plunger supported for reciprocating movement along the axis of rotation and selectively actuating the vent valve in response to movement of the lock mechanism from the locked position to the unlocked position..Iaddend..Iadd.72. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising   a closure adapted for engaging and closing the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell in communication with the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve being configured to equalize fuel vapor pressure between the filler neck and the atmosphere,   a lock mechanism coupled to the shell, the lock mechanism being movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell and the closure for movement of the closure in the cap-removing direction, and   a plunger being supported for reciprocating movement along the axis of rotation during movement of the lock mechanism between the locked position and the unlocked position, the plunger selectively actuating the vent valve in response to movement of the lock mechanism from the locked position to the unlocked position..Iaddend..Iadd.73. The cap of claim 72, further comprising a retainer positioned to lie between the closure and shell..Iaddend..Iadd.74. The cap of claim 73, wherein the lock mechanism includes a cam and further comprising a cam follower positioned on the plunger and configured to selectively engage the cam to move the plunger along the axis of rotation during movement of the lock mechanism to the   
     
     
        unlocked position..Iaddend..Iadd.75.  The cap of claim 74, wherein the retainer is constructed of metal..Iaddend..Iadd.76. The cap of claim 74, wherein the lock mechanism includes a lock and a throw member coupled to the lock and configured to define the cam..Iaddend..Iadd.77. The cap of claim 76, wherein the key-actuated throw member is coupled to the lock and configured to rotate relative to the lock in response to turning a key in the keyway urging the cam against the cam follower to move the plunger as the throw member rotates relative to the lock..Iaddend..Iadd.78. The cap of claim 76, wherein the closure is formed to include an interior region and the lock is positioned to extend into the interior region..Iaddend..Iadd.79. The cap of claim 78, wherein the plunger includes an annular ramp positioned to wind around the axis of rotation and to engage the throw member during movement of the lock mechanism to the unlocked position and a neck positioned to move along the axis..Iaddend..Iadd.80. The cap of claim 74, wherein the cam follower is an annular ramp positioned to wind around the axis of rotation..Iaddend..Iadd.81. The cap of claim 72, further comprising a race engaging the closure and a drive hub coupled to the shell and configured to selectively engage the race to provide a cap-installing driving connection between the shell and the closure for movement of the closure in a cap-installing direction..Iaddend..Iadd.82. The cap of claim 81, wherein the drive hub includes means for disengaging the cap-installing driving connection in response to movement of the shell in a cap-removing direction..Iaddend..Iadd.83. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising a closure formed for engaging and closing the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell adapted to permit manual rotation of the closure,   a vent valve for equalizing fuel vapor pressure between the filler neck and the atmosphere,   a lock coupled to the shell and movable from a locked position to an unlocked position to establish a cap-removing driving connection between the shell and the closure for movement of the closure in the cap-removing direction, the lock including a cam, and   a plunger configured to selectively actuate the vent valve in response to movement of the lock from the locked position to the unlocked position, the plunger including a cam follower selectively engaging the cam during movement of the lock to the unlocked position to urge the plunger to a   
     
     
        vent-actuating position..Iaddend..Iadd.84.  The cap of claim 83, further comprising a metal retainer coupled between the closure and shell to retain shell on closure and to reinforce the shell..Iaddend..Iadd.85. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising a closure including a threaded shank formed for rotatably engaging and closing the filler neck the closure being movable relative to the filler neck between a removed position and an installed position,   a shell adapted to permit manual rotation of the closure,   a vent valve for equalizing fuel vapor pressure between the filler neck and the atmosphere,   a lock coupled to the shell and movable from a locked position to an unlocked position for selectively locking and unlocking the fuel cap,   a removal hub in communication with the shell and the closure to provide a cap-removing driving connection therebetween in response to movement of the lock from the locked position to the unlocked position to move the closure in a cap-removing direction, and   a plunger configured to selectively actuate the vent valve in response to movement of the lock from the unlocked position..Iaddend..Iadd.86. The cap of claim 85, wherein the plunger is drivingly connected to the removal hub in response to movement of the lock to the unlocked position..Iaddend..Iadd.87. The cap of claim 86, wherein the plunger includes first drive teeth and the removal hub includes second drive teeth positioned to lie in a complementary relationship with the first drive teeth to establish the cap-removing driving connection between the closure and the shell..Iaddend..Iadd.88. The cap of claim 87, wherein the plunger includes first ramping surfaces and the removal hub includes second ramping surfaces positioned to lie in a complementary relationship with the first ramping surfaces and the first and second ramping surfaces ramp against each other in response to movement of the shell relative to the closure in the cap-installing direction..Iaddend..Iadd.89. The cap of claim 85, further comprising a metal retainer coupled between the closure and shell..Iaddend..Iadd.90. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising   a closure formed for rotatably engaging and closing the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell adapted to permit manual rotation of the closure,   a lock coupled to the shell and movable from a locked position to an unlocked position for selectively locking and unlocking the fuel cap,   a plunger having a finger movable between an engaged position and a driving connection-maintaining position, the finger moving to the driving connection-maintaining position in response to movement of the lock to the unlocked position and moving to the engaged position in response to movement of the shell relative to the closure in the cap-installing direction, and   uncoupling means for automatically disabling the cap-removing driving connection in response to movement of the shell relative to the closure in the cap-installing direction when the lock is in the locked   
     
     
        position..Iaddend..Iadd.91.  The cap of claim 90, further comprising a metal retainer coupled between the closure and shell..Iaddend..Iadd.92. The cap of claim 90, further comprising a vent valve positioned to lie within the closure, the vent valve is configured to equalize fuel vapor pressure between the filler neck and the atmosphere through the closure and the plunger is formed for movement from a vent valve-opening position to a vent-valve closing position in response to movement of the shell relative to the closure in the cap-installing direction..Iaddend..Iadd.93. A lockable fuel cap for closing a filler neck of a fuel tank, the cap comprising a closure formed for rotatably engaging and closing the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position,   a shell adapted to permit manual rotation of the closure,   a lock coupled to the shell and movable from a locked position to an unlocked position for selectively locking and unlocking the fuel cap,   a removal hub coupled to the closure, and   a plunger selectively coupled to the removal hub, the lock, removal hub, and plunger cooperating to establish a cap-removing driving connection between the shell and the closure in response to movement of the lock to the unlocked position for movement of the closure in a cap-removing direction..Iaddend..Iadd.94. The cap of claim 93, wherein the plunger is rotationally locked to the shell and the removal hub is rotationally locked to the closure and the plunger includes ramps that engage the lock and drive the plunger into engagement with the removal hub in response to movement of the lock to the unlocked position..Iaddend..Iadd.95. The cap of claim 94, further comprising a retainer coupled between the closure and   
     
     
        shell..Iaddend..Iadd.96.  A fuel cap for closing a filler neck of a fuel tank, the cap comprising: a closure including a shank portion adapted to engage and close the filler neck, the closure being movable relative to the filler neck between a removed position and an installed position, the closure further including a radially outwardly extending flange coupled to the shank portion,   a gasket coupled to the closure,   a shell positioned to lie adjacent to the closure to permit manual rotation of the closure about an axis of rotation,   a vent valve positioned to lie within the closure, and   a metal retainer positioned to lie within the shell, the entire metal retainer being positioned to lie above the gasket, and a portion of the metal retainer being positioned to lie below the radially outwardly extending flange..Iaddend..Iadd.97. The cap of claim 96, wherein the metal retainer includes a circumferential skirt arranged to engage the shell, an annular inner rim arranged to lie in spaced-apart relation to the circumferential skirt, and an annular connector coupled to the annular inner rim and to the circumferential skirt and arranged to engage the radially outwardly extending flange..Iaddend..Iadd.98. The cap of claim 97, wherein the annular connector includes an axially upwardly facing curved upper surface underlying and engaging the radially outwardly extending flange..Iaddend..Iadd.99. The cap of claim 97, wherein the annular inner rim includes an annular inner edge arranged to define an opening receiving the shank portion of the closure   
     
     
        therein..Iaddend..Iadd. 00.  The cap of claim 97, wherein the annular inner rim lies in a horizontal plane and the circumferential skirt is tangent to a vertical plane that is orthogonal to the horizontal plane..Iaddend..Iadd.101. The cap of claim 97, wherein the annular connector is formed to include an axially downwardly facing curved lower surface facing away from the radially outwardly extending flange and defining an annular channel..Iaddend..Iadd.102. The cap of claim 96, wherein the closure further includes a gasket flange positioned to lie between the gasket and the radially outwardly extending flange and to engage the gasket and a portion of the metal retainer is positioned to lie above the gasket flange and below the radially outwardly extending flange..Iaddend..Iadd.103. The cap of claim 102, wherein the metal retainer includes a circumferential skirt arranged to engage the shell, an annular inner rim arranged to lie in spaced-apart relation to the circumferential skirt, and an annular connector coupled to the annular inner rim and to the circumferential skirt and arranged to engage the radially outwardly extending flange, and the annular rim and the annular connector cooperate to define said portion of the metal retainer..Iaddend..Iadd.104. The cap of claim 102, wherein the portion of the metal retainer includes an annular inner rim formed to include an opening receiving the shank portion of the closure therein..Iaddend..Iadd.105. The cap of claim 102, wherein the portion of the metal retainer includes an annular connector coupled to the annular inner rim and to the circumferential skirt and wherein the annular connector includes an axially upwardly facing curved upper surface underlying and engaging the radially outwardly extending flange..Iaddend..Iadd.106. The cap of claim 102, wherein the shell and the gasket flange cooperate to define a retainer-receiving space therebetween and the metal retainer includes a circumferential skirt arranged to engage the shell and lie in the retainer-receiving space..Iaddend.