Abstract:
In one embodiment disclosed is a safety fuel tank and filler cap apparatus for supplying fuel to an internal combustion engine that can be started with a magnetoelectric generator, comprising an exposed fuel tank having a fill opening, an annular fuel filler flange surrounded by an adjoining fuel tank wall having outer surface, said flange having a central axis; a filler cap having a cap center, the cap being connectable to the fuel filler flange to form a closure of the tank at the fill opening when the cap center generally aligns with the flange central axis, said filler cap and adjoining fuel tank outer surface being configured to enable a user to grip and turn said fuel filler cap, at a position next to the tank wall; and a mechanism interfaced between the fuel tank and filler cap that is activated to a safety mode when the engine is at an elevated, operating temperature, said mechanism including a connector that interfaces between the outer surface of the fuel tank and the cap. In another embodiment disclosed is a powered implement, comprising: a frame; an internal combustion engine mounted on the frame, said engine including a magnetoelectric generator for starting the engine; the frame and engine supporting an exposed fuel tank having a tank wall and a fill opening through said tank wall for receiving fuel for powering the engine; a fuel filler flange on said tank surrounded by an adjoining fuel tank outer surface, said flange extending a short distance from tank wall and surrounding the filler opening; a filler cap that fits the fuel filler flange to form a closure of the tank at the fill opening, said filler cap and adjoining fuel tank outer surface being configured to enable a user to grip and turn said fuel filler cap; and a device interfaced between the fuel tank and filler cap that responds to an attempt by a user to open the filler cap when the engine is at an elevated, operating temperature that is near the ignition temperature of the fuel that powers the engine.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation in part of U.S. Ser. No. 09/452,653 filed Dec. 1, 1999 (now U.S. Pat. No. 6,260,516) which is a continuation-in-part of U.S. Ser. No. 09/288,402 filed Apr. 8, 1999 (now U.S. Pat. No. 6,112,714) which is a continuation-in-part of U.S. Ser. No. 09/267,877, filed Mar. 11, 1999 (now abandoned). Priority to all three applications is claimed and all are incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to small internal combustion engines of the type that are used to power lawn mowers, tillers, lawn vacuums, weed trimmers, snow blowers, water blasters and the like. Even more particularly, the present invention relates to an improved safety fuel tank and filler cap apparatus which enters a safety mode and alerts a user who grasps and turns the fuel cap (or when the fuel cap loosens) that gasoline should not be added to the fuel tank when various conditions exist. In one embodiment the apparatus automatically disables the magnetoelectric generator when a fuel filler cap portion of the apparatus is separated from a fuel filler flange such as when the fuel filler cap inadvertently disconnects from the fuel tank or is removed for filling the fuel tank. In another embodiment, the safety fuel tank and filler cap apparatus disallows removal of the fuel filler cap portion of the apparatus from the fuel tank when the engine is too hot, such as above a selected safe threshold temperature value. 
     2. General Background of the Invention 
     The flash point of a liquid such as gasoline should not be confused with the temperature necessary to ignite the vapors, for unless a source of heat considerably hotter than the flash point of the fuel comes into direct contact with the vapors, the fuel will merely give off vapors without burning. An essential factor in the process of combustion is oxygen. Without oxygen, even the most flammable vapors will not combust. Under normal conditions, a flame draws the amount of oxygen necessary to sustain combustion from the air. When the oxygen content of the air falls below about 15%, there is an immediate extinguishment of practically all flames. 
     There is typically a wide temperature difference between the flash point of a fuel and the ignition temperature. For example, the flash point (vapor given off) of gasoline is minus 43 degrees centigrade (minus 45.4 degrees Fahrenheit), and the ignition temperature (heat necessary to ignite the mixture) is about 257 degrees centigrade (494.6 degrees Fahrenheit). A small flame can be drawn into lube oil which is at average room temperature and it will not burn, but with the addition of burning gasoline, vapors soon rise and burn to raise the temperature of the surrounding oil to the flash point. 
     Every year, fires cause serious and sometimes fatal bodily injury to operators of outdoor, yard and garden, and like implements such as lawn mowers, lawn vacuums, weed trimmers, water blasters, and the like. One of the most common safety problems is associated with the attempt by individuals to add gasoline to the internal combustion engine of a lawn mower or like implement that is still running. Sometimes, an implement gradually loosens the gas filler cap because of vibration. Typically, these implements position the fuel tank and its filler neck at or near the engine block. 
     Fuel that spills from the fuel tank or from a supply container when filling the tank may come into contact with hot surfaces on the engine block or accessories. If the user is not paying close attention to the gas tank and its filler cap, gasoline can begin to leak when the cap is loosened. This problem is especially acute with rear drive type implements such as all terrain vehicles, go-karts, riding lawn mowers and lawn tractors wherein the gasoline tank may be behind the operator or underneath a seat or hood preventing the user from seeing it. Many tractor style riding lawn mowers have such a hidden fuel tank and filler cap. 
     Many of these implements are operated by adolescent children that are not warned sufficiently by their parents about the danger of filling tanks with gasoline when the implement or vehicle is hot from operation. 
     Many manufacturers use decal warning stickers and user&#39;s manual warnings to warn a user to not remove the fuel filler cap until the engine cools for at least a couple of minutes. 
     Despite warnings, many users smoke when operating such an implement, so that if the cap loosens, the operator does not notice the escape of fumes if the engine continues to run. 
     Generators are often filled with gasoline by a user when still running because the user does not want to interrupt the flow of electricity. 
     All of the above situations are hazardous if the engine continues to run when the filler cap is removed or becomes removed, or if a user attempts to fill the fuel tank when the engine is very hot. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an improved safety fuel tank and filler cap apparatus for supplying fuel to an implement powered by an internal combustion engine that can be started with a magnetoelectric generator. The implement can be, for example, a lawn mower, go-kart, garden tractor, lawn vacuum, snow blower, tiller, chain saw, weed trimmer, hedge clipper, or log splitter. 
     The apparatus includes an exposed fuel tank having a fill opening, a fuel filler flange surrounded by an adjoining fuel tank outer surface, the flange extending a short distance from the filler opening in the fuel tank wall. A filler cap fits the fuel filler flange to form a closure of the tank at the fill opening, the filler tank and adjoining fuel tank outer surface being configured to enable a user to grip and turn the fuel filler cap. A switch is interfaced between the fuel tank and filler cap that disables the magnetoelectric generator when the filler cap is removed from the fuel filler tank. This construction prevents the user from filling the fuel tank with gasoline when the engine is running. 
     The switch can be a magnetic switch, a photoelectric switch, or a mechanical switch, for example a button switch, toggle switch, rocker switch. The mechanical switch can be a switch that moves between operating and disabled positions, the switch including a moving member that shifts positions when the fuel filler cap is separated from the fuel filler flange. 
     The switch can include a magnetic switch member mounted in the fuel tank and another magnetic switch member mounted on the filler cap. The switch can include a switch member mounted on the filler cap the does not interfere with the sealing of the fuel filler flange with the filler cap, being spaced from the threads or bayonet connectors that join the cap and tank. 
     The filler cap can have a top, an annular skirt with internal threads, and wherein the switch member is mounted on the annular skirt in between the threads and the top. Such internal threads form a threaded engaged connection with external threads on the fuel filler flange. The fuel filler cap preferably has a top, an annular skirt with a threaded portion thereon, and an unthreaded outer surface and wherein the switch member is mounted on the annular skirt. The switch member can be mounted on an unthreaded portion of the filler cap. 
     In another embodiment, the present invention provides an improved safety fuel tank and filler cap apparatus for supplying fuel to an internal combustion engine that includes an exposed fuel tank having a fill opening, a fuel filler flange surrounded by an adjoining fuel tank outer surface, the flange extending a short distance from the filler opening in the fuel tank wall. A filler cap fits the fuel filler flange at the fill opening, the filler tank and adjoining fuel tank outer surface being configured to enable a user to grip and turn the fuel filler cap. A locking mechanism is interfaced between the fuel tank and filler cap that disallows removal of the filler cap. This construction prevents the user from filling the fuel tank with gasoline when the engine is still running or not running but still very hot. 
     The present invention also teaches and provides a powered implement having a frame, an internal combustion engine mounted on the frame that includes a magnetoelectric generator for starting the engine, and including an exposed fuel tank having a fill opening, a fuel filler flange surrounded by an adjoining fuel tank outer surface, the flange extending a short distance from the filler opening in the fuel tank wall and wherein a filler cap fits the fuel filler flange to form a closure of the tank at the fuel opening. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
     FIG. 1 is a perspective view of the preferred embodiment of the apparatus of the present invention; 
     FIG. 1A is perspective view of the preferred embodiment of the apparatus of the present invention used with an auxiliary tank; 
     FIG. 1B is a perspective view of the preferred embodiment of the apparatus of the present invention showing a powered implement in the form of a weed trimmer; 
     FIG. 2 is a partial sectional elevational view of the preferred embodiment of the apparatus of the present invention; 
     FIGS. 3A-3B are schematic diagrams of the preferred embodiment of the apparatus of the present invention shown in engine operating (FIG. 3A) and engine disabled (FIG. 3B) positions; 
     FIG. 4 is a side elevational view of a second embodiment of the apparatus of the present invention; 
     FIGS. 5A-5B are schematic sectional elevational views of the second embodiment of the apparatus of the present invention showing the switch in engine operating (FIG. 5A) and engine disabled (FIG. 5B) positions respectively; 
     FIG. 6 is an elevational view of a third embodiment of the apparatus of the present invention; 
     FIG. 7 is a perspective view of the third embodiment of the apparatus of the present invention; 
     FIG. 8 is a perspective view of a fourth embodiment of the apparatus of the present invention; 
     FIG. 9 is a partial perspective view of the fourth embodiment of the apparatus of the present invention; 
     FIG. 10 is an exploded perspective view of the fourth embodiment of the apparatus of the present invention; 
     FIG. 11 is a sectional elevational, exploded view of the fourth embodiment of the apparatus of the present invention; 
     FIGS. 12A,  12 B,  12 C are upper perspective, bottom perspective, and bottom views respectively of a filler cap construction having a bayonet type mount and that can be used with the embodiments of FIGS. 1-11; 
     FIGS. 13A,  13 B and  13 C are upper perspective, bottom perspective, and bottom views respectively of another filler cap construction having a bayonet mount that can be used with the embodiment of FIGS. 1-11; 
     FIGS. 14-15 are perspective views of a hinged filler cap construction that can be used with the embodiment of FIGS. 1-11, showing closed and open positions respectively of the filler cap; 
     FIG. 16 is an exploded view of a fifth embodiment of the apparatus of the present invention; 
     FIG. 17 is a fragmentary plan view of the fifth embodiment of the apparatus of the present invention showing a micro switch type switch arrangement; 
     FIG. 18 is a fragmentary plan view of the fifth embodiment of the apparatus of the present invention shown with a plunger switch type switch arrangement; 
     FIG. 19 is a fragmentary plan view of the fifth embodiment of the apparatus of the present invention shown with a magnetic switch, proximity switch, or optical switch arrangement; 
     FIGS. 20A-20B are schematic wiring diagrams of the fifth embodiment of the apparatus of the present invention respectively showing ignition system on and ignition system off wiring diagrams; 
     FIGS. 21A-21B are alternate circuit drawings showing an ignition system for the present invention in respective “on” and “off” positions; 
     FIG. 22 is a perspective view of a sixth embodiment of the apparatus of the present invention; 
     FIG. 23A is a fragmentary elevational view of the sixth embodiment of the apparatus of the present invention; 
     FIG. 23B is a fragmentary view of the sixth embodiment of the apparatus of the present invention shown in locking position; 
     FIG. 24 is a schematic top view of the sixth embodiment of the apparatus of the present invention showing the cap in an unlocked position; 
     FIG. 25 is a schematic top view of the sixth embodiment of the apparatus of the present invention showing the cap in a locked position; 
     FIGS. 26A-26B are perspective views of a seventh embodiment of the apparatus of the present invention; 
     FIG. 27 is a perspective view of an eighth embodiment of the apparatus of the present invention; 
     FIGS. 28A-28B are perspective fragmentary views of a ninth embodiment of the apparatus of the present invention; 
     FIG. 29 is a schematic view of a tenth embodiment of the apparatus of the present invention; and 
     FIG. 30 is an schematic view of an eleventh embodiment of the apparatus of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1,  1 A and  1 B show the preferred embodiment of the apparatus of the present invention designated generally by the numeral  10  in FIGS. 1,  1 A and  1 B. 
     Safety fuel tank and cap apparatus  10  includes a safety system that disables internal combustion engine E if a user removes the fuel filler cap  19  from cylindrically shaped flange  16  of fuel tank  14 . Engine E can be any small two stroke or four stroke engine for operating a lawnmower, tiller, weed trimmer, chainsaw, generator, go-kart, or the like. Engine E can be a type that includes a magnetoelectric generator  11  that can be operated with an electric starter (not shown) or a pull cord starter rope  12 . In one embodiment of the present invention, electrical circuit  13 ,  28  is provided for disabling magnetoelectric generator  11  when filler cap  19  is removed from fuel tank  14 . An electrical cable  13  extends between a switch  28  mounted on the upper surface  15  of fuel tank  14  and the magnetoelectric generator or “magneto”  11 . 
     The fuel filler cap  19  in FIG. 2 provides an internally threaded portion  23  that interlocks with external thread  17  on cylindrically shaped flange  16 . The cylindrically shaped flange  16  surrounds fuel tank opening  18 . 
     Filler cap  19  is comprised of a circular top portion  21  and a generally cylindrically shaped annular skirt  20 . The top portion  21  is joined to the skirt  20  at annular edge  37 . Skirt  20  has an inner annular, generally cylindrically shaped surface  20 A and an outer annular generally cylindrically shaped surface  20 B. Skirt  20  outer surface  20 B can be knurled or ribbed to ease gripping by a user. Inner surface  20 B can be threaded (see FIGS. 2,  3 A- 3 B,  5 A- 5 B) or a bayonet mount (see FIGS. 14-15 ). Handle  22  is positioned on top  21  for enabling a user to remove cap  19  from flange  16  or for engaging cap  19  with flange  16 . The cap  19  can include a vent  24  for releasing fumes. 
     The filler cap  19  can be an internally threaded cap as shown in FIGS. 1-11. Alternatively, the filler cap can be a bayonet type cap  19 A,  19 B as shown in FIGS. 12A,  12 B,  12 C,  13 A,  13 B and  13 C. Such a bayonet mount type cap  19 A,  19 B is used on engines such as those sold under the marks Honda® and Briggs® for example. 
     A magnet  25  is embedded in the unthreaded upper portion of cap  19  next to top  21  as shown in FIG.  2 . Magnet  25  provides an outer end  26  that is positioned next to the annular skirt  20 . The inner end  27  of magnet  25  is positioned nearer the center of circular top as show in FIG.  2 . 
     Switch  28  is preferably a magnetic member that is mounted on upper surface  15  of fuel tank  14  adjacent to cylindrically shaped flange  16 . Magnetic switch  19  includes an electrical cable  29  that communicates with electrical cable  13  extending to magneto  11 . The electrical cable  13  can include a pair of wire leads  29 A,  29 B as shown in FIGS. 3A,  3 B. Lead  29 B connects to ground  30  as shown in FIGS. 3A,  3 B. 
     In FIG. 3A, the magnet  25  is shown with its outer end  26  positioned next to magnetic switch  28 . Spring  33  is overcome by magnet  25  so that it pulls contact plate  34  toward magnet  25  and away from contact points  35 ,  36 . This condition shown in FIG. 3A occurs when the gas filler cap  19  is in a fully closed position. In this closed position, the magnet  25  is generally aligned with the magnetic switch  28  as shown in FIGS. 1,  1 A,  1 B,  2  and  3 A. 
     In FIG. 3B, a user has separated the gas filler cap  19  from cylindrically shaped flange  18  as indicated schematically by arrow  31 . In such a situation, the spring  33  forces contact plate  34  into contact with leads  35 , 36 . Arrows  32  in FIG. 3B indicate schematically the movement of contact plate  34  into contact with points  35 ,  36 . In such a situation, electrical power generated by the magneto is unable to start the engine E. 
     In FIGS. 4,  5 A and  5 B, there is shown a second embodiment of the apparatus of the present invention designated generally by the numeral  40  in FIG.  4 . Safety fuel tank and cap apparatus  40  includes a cap  41  having a handle  42 . Cap  41  can also provide a vent  43 . The cap  41  is comprised of a generally cylindrically shaped annular skirt  44  and a circular top  45 . 
     An appendage  46  extends radially outwardly of skirt  41  as shown in FIGS. 4,  5 A and  5 B. The appendage  46  has an under surface  47  that engages switch button  53  of button switch  48 . The button switch  48  is shown in FIG. 5A in an operating position wherein appendage  46  holds the button  53  in a lowermost position that spaces contact plate  52  away from contacts  49 ,  50 . As shown in FIG. 5B when cap  41  is removed from cylindrically shaped filler flange  16  as shown by arrow  54 , the spring  51  moves switch button  53  upwardly so that contact plate  52  engages contacts  49 ,  50  as shown by arrow  55 . In such a situation, the magneto  11  will not start the engine E. 
     FIGS. 6 and 7 show a third embodiment of the apparatus of the present invention designated generally by the numeral  56  in FIG.  7 . Safety fuel tank and cap apparatus  56  features a filler cap  57  that is threadably engagable with annular skirt  16  as with the embodiments of FIGS. 1-5. Annular skirt  58  connects to a circular top  59  having handle  60 . Switch  61  is mounted on the upper surface  15  of tank  14  as shown in FIGS. 6 and 7. The switch  61  includes a switch housing  62  that carries an electric eye  63 . Such a switch  61  is commercially available. Arrow  64  in FIG. 7 indicates the communication between electric eye  63  and reflector  65  contained in opening  66  surrounded by annular rib  67 . In the embodiment of FIG. 6 and 7, the electric eye is emitting a light source that reflects off reflector  65  and which is interrupted when cap  57  is removed from flange  16  so that the electrical cable  13  communicating with magneto  11  closes a circuit that prevents operation of magneto  11  to start engine E. 
     FIGS. 8-11 show a fourth embodiment of the apparatus of the present invention designated generally by the numeral  68  in FIG.  8 . Safety fuel tank and cap apparatus  68  includes a micro switch  69  having a switch arm  70  that includes a ring  71 . The ring  71  surrounds opening  72  that fits over flange  16  and under filler cap  74  as shown in FIGS. 8-11. The ring  71  attaches to micro switch  69  with beam  73 . Such a micro switch  69  is commercially available. 
     Filler cap  74  has a circular top  75  and a cylindrically shaped annular skirt  76 . Handle  77  enables cap  74  to be able to be manipulated and turned such as when it is removed from or engaged with cylindrically shaped flange  16 . A shroud  78  is provided for covering the combination of the micro switch  69  and its arm  70  as shown in FIGS. 10 and 11. The shroud  78  communicates with cover  79  that can be bolted over the shroud  78  using a plurality of bolts  80 . Arrow  81  in FIG. 11 shows how the micro switch  69  is closed when the cap  74  is threaded upon flange  16  as indicated schematically by arrow  81  in FIG.  11 . In such a situation, the lower annular edge  84  of cap  74  engages ring  71  of switch arm  70  forcing it downwardly and operating switch  69  to deactivate magneto  11  via electrical cable  13 . 
     FIG. 1A shows the apparatus  10  of the present invention attached to an auxiliary fuel tank  14  having a fuel line  82 . In FIG. 11B, a powered implement is shown in the form of a weed trimmer that includes a frame  85  that supports an internal combustion engine E having fuel tank  14  and filler cap  19  with magnetic switch  28 . 
     Filler cap  19 A in FIGS. 12A,  12 B and  12 C is a Honda® type cap that can have a circular top  38 , annular skirt  39  with generally cylindrically shaped outer surface  88 , and annular edge  89  at the interface between top  38  and skirt  39 . Cap  19 A includes bayonet mount projections  86 ,  87  that interlock with a bayonet type flange (not shown on tank  14  ). Cap  19 A can have gasket  95 . Such an interlocking arrangement between projections  86 ,  87  and bayonet type flange on a fuel tank is known in the art (see for example small (e.g. 5 hp or 13,238 kilojoules) engines sold under the marks Briggs®, Honda@, and Kawasaki®. 
     FIGS. 13A,  13 B and  13 C show a Briggs® type cap arrangement. Cap  19 B has top  90 , annular skirt  91  that joins top  90  at annular edge  92 . Projections  93 ,  94  connect to fuel tank  14  at a filler flange having a bayonet type mount. Cap  19 B has gasket  95 . 
     In FIGS. 12A,  12 B and  12 C there can be seen magnetic switch  28  (FIG. 12A) used with cap  19 B, the use of a photoelectric switch at opening  66  (FIG. 13B) and the use of appendage  46  (FIG. 12C) for use with button switch  48 . In FIGS. 13A,  13 B and  13 C there can be seen magnetic switch  28  (FIGS.  12 A), opening  66  with reflector  65  as part of a photoelectric switch, and (in FIG. 12C) an appendage  46  for use with button switch  48 . 
     FIGS. 12A,  12 B,  12 C  13 A,  13 B and  13 C illustrate that a bayonet type filler cap and tank flange arrangement could be used with any of the embodiments of FIGS. 1-11. 
     In FIGS. 14 and 15 there is shown a hinged filler cap  19 C arrangement that can be used with any of the embodiments of FIGS. 1-11. Hinge  96  supports spring loaded cap  97  that automatically springs open to the open position of FIG. 14 when spring loaded latch  98  is moved away from cap  97  in the direction of arrow  104 . Latch member  98  is pivotally mounted to tank surface  15  at pivot  99 . A pair of sears  100  normally hold cap  97  in the closed position of FIG.  15 . When the cap  97  is closed, sears  100  are engaged and latch  98  pushed away in the direction of arrow  104  until cap  97  closes fully upon flange  16 A at which time sears  100  engage and hold cap  97 . This general concept of a cap  97 , hinge  96 , latch  98  and flanged opening  16 A,  18  is known and commercially available. Cap  97  has flat top  101 , skirt  102  and skirt outer surface  103 . 
     Following the teachings of the present invention, cap  97  could carry a magnet  25  that cooperates with switch  28  as in FIGS. 1-3. The cap  97  could carry a projection or appendage  46  as with the embodiment of FIGS. 4,  5 A and  5 B that cooperates with button switch  48 . The cap  97  could also carry reflector  66  in opening  65  for use with photo electric switch  61  as in FIGS. 6-7. 
     Any of the cap constructions shown in FIGS. 12A,  12 B,  12 C,  13 A,  13 A,  13 B and  13 C or  14 - 15  can be used in combination with the micro switch arrangement of FIGS. 8-11. 
     FIG. 16 shows a fifth embodiment of the apparatus of the present invention designated generally by the numeral  105 . In FIG. 16, fuel tank  106  has an upper surface  107  with a fuel filler neck  108 . In the embodiment of FIG. 16, a fuel filler neck  112  can be added to the existing fuel filler neck  108  on tank surface  107 . As an option, an adapter  111  can be placed in between the permanent fuel filler neck  108  of tank surface  107  and the retrofitted fuel filler neck  112 . The adapter  111  can be a cylindrically shaped or donut shaped fitment or shim that fits in between the side wall  109  of filler neck  108  and the new filler neck  112 . 
     Filler neck  108  has an annular shoulder  110  that surrounds a central opening through which fuel can be added to the tank surface  107 . The new filler neck  112  has a side wall  113  and an upper annular shoulder  114  that carries a pair of spaced apart slots  115 ,  116 . These slots  115 ,  116  receive projections  86 ,  87  of the fuel filler cap  38  shown in FIGS. 12A,  12 B,  12 C or the filler cap  90  shown in FIGS. 13A,  13 B,  13 C. 
     The switch S in FIG. 16 schematically represents any of the selected switches that are discussed herein with respect to the embodiments of FIGS. 1-15, or any of the switches shown in FIGS. 17-19. Similarly, the projection P in FIG. 16 represents the portion of an overall switch arrangement that is carried at the periphery of a cap  19 ,  38  or  90 , for any of the embodiments of FIGS. 1-15 or  17 - 21  B. 
     In FIG. 17, a micro switch  117  is shown that cooperates with a projection  119  carried by cap  38  at the periphery of cap  38 . The micro switch  117  has an arm  118  that is depressed in order to close the switch when the cap  38  is in a fully closed position engaging a fuel filler neck such as  112  or  16 . 
     In FIG. 18, a plunger type switch arrangement is shown that includes a plunger type switch  120  having a housing  122  that carries a plunger  121 . The plunger  121  closes relative to the housing  122  when it is depressed by projection  119 . The projection  119  is carried at the periphery of cap  38  or any of the other fuel filler caps disclosed herein when the cap  38  is in its, fully closed position. The switch  120  opens to shut down the engine when the projection  119  is moved away from plunger  121 . 
     In FIG. 19, a projection  25  at the periphery of cap  38  can be a portion that cooperates with a magnetic switch, proximity switch, or optical switch, designated generally by the letter S in FIG.  19 . 
     In FIGS. 20A and 20B, there is shown a wiring diagram for a ground to shut down arrangement. In FIG. 20A, an ignition system is indicated by the numeral  123  and key switch by the numeral  124 . The numeral  125  indicates schematically any other ignition shut down switch. In FIG. 20A, the engine will not run if any switch is closed. Removing the fuel cap  19 ,  38  or  90  closes the switch S so that the engine will not run. All of the switches are wired and parallel to each other in FIG.  20 A. 
     In FIG. 20B, the ignition system is shown in an off position. The fuel cap switch S is closed when the cap  19 ,  38  or  90  is not secured to the tank, and the engine will not run. The fuel cap system shown in FIG. 20B will work on any type of ignition system/shut off system including magneto type, coil type, negative and positive ground, ground to run and ground to shut down. 
     FIGS. 21A and 21B show other examples of wiring diagrams for “ignition system on” and “ignition system off” configurations respectively. 
     FIGS. 22-24 show a sixth embodiment of the apparatus of the present invention designated generally by the numeral  128  in FIG.  22 . Safety fuel tank and cap apparatus  128  in FIG. 22 is used with an internal combustion engine  129 , such as a lawn mower engine having a starter  130 , starter solenoid  131 , and powered by battery  132 . 
     Engine  129  has a fuel tank  139  that is often closely positioned to the engine block  129 A of engine  129 . Fuel tank  139  has an opening for enabling fuel to be added, and a fuel filler closure cap  140  that can seal the fuel tank opening. This overall arrangement of engine  129 , battery  132 , fuel tank  139  is the same for all embodiments. 
     Wiring interconnecting battery  132 , engine  129  and the remaining components of the apparatus  128  of the present invention are shown in FIG.  22 . Such wiring includes ground  133  that communicates with battery  132  via battery cable  134  and cable  135  that communicates with starter solenoid  131 . Cable  136  extends between battery  132  and heat sensor  137 . A cable is also provided that links starter  130  and starter solenoid  131 . 
     Cable  138  extends between heat sensor  137  and actuator  141 . Actuator  141  is preferably mounted upon fuel tank  139  next to fuel filler cap  140  as shown in FIG.  22 . The actuator  141  defines a locking mechanism that prevents the filler cap  140  from being removed when the engine temperature is above a predetermined temperature that is near or below the ignition temperature of the fuel (or fuel vapor) in and around tank  139 . 
     Actuator  141  includes switch housing  142  having a housing interior  143  that contains plunger  148 , as shown in FIGS. 24 and 25. Wire lead  26  is contained within cable  20  for supplying electrical power to actuator  23  as shown in FIGS. 24 and 25. Wire lead  144  connects to coil  146  at terminal  145 . Coil  146  is preferably grounded, eg. with wire lead  147  to switch housing  142 . 
     Plunger  148  moves between locked and unlocked positions. FIG. 23A shows the unlocked position of plunger  148 . FIG. 23B shows the locked position of plunger  148 . Plunger  148  is mounted within housing interior  143  through an opening at the center of coil  146 . One end of plunger  148  is supported by flange  149  and spring  150 . The other end of plunger  148  is supported by housing  142  at the opening through which plunger  148  extends. The actuator  141  functions as a solenoid to move the plunger  148  between locking and unlocking positions. Spring  150  normally holds plunger  148  in the unlocked position of FIG.  23 A. The spring  150  extends between anchor plate  151  and plunger  148  at flange  149 . 
     Cap  140  has a plurality of circumferentially spaced radially extending recesses  153 , each sized and shaped to form a connection with plunger  148  at end portion  154 . In FIG. 23A, arrows  152  indicate the movement of plunger  148  from an unlocked position to a locked position. During operation, heat sensor  137  monitors the temperature of engine  129 . When the temperature of engine block  129 A of engine  129  reaches a predetermined temperature that is at or near the ignition temperature of gasoline, heat sensor  137  sends an electrical signal via wire lead  144  to actuator  141  activating coil  146  to move plunger  148  to the locked position of FIG.  23 B. When the temperature sensed by heat sensor  137  drops below a predetermined acceptable temperature value, the heat sensor  137  halts the electrical flow to actuator  141  so that return spring  150  moves plunger  148  to the unlocked position of FIG.  23 A. 
     FIGS. 24 and 25 show the sixth embodiment  128 A of the apparatus of the present invention using switch  155 . Switch  155  is in the form of a coil  156  having contact bar  157 . A pair of terminals  158 ,  159  are positioned next to contact bar  157  as shown in FIGS. 24 and 25. When excessive heat, indicated by heat wave lines  160  in FIG. 25 is transferred to switch  155 , coil  156  expands, pushing contact bar  157  into contact with terminals  158 ,  159 . As the circuit is closed, battery  132  is able to supply power to actuator  141 , closing a circuit activating plunger  148  and engaging the projecting portion  154  into a recess  153  of cap  140  as indicated by arrow  152  in FIG.  25 . 
     Another (seventh) embodiment of the apparatus  128 B of the present invention is shown in FIGS. 26A and 26 B. In FIGS. 26A and 26B, cap  161  is mounted upon hinge  162  to move between open and closed positions as indicated by arrow  164  in FIG.  26 B. Latch  163  can be used to latch cap  161  in the closed position of FIG.  26 A. The latch  163  can be depressed to open cap  161  as shown in FIG.  26 B. Cap  161  closes opening  166  that is surrounded by filler neck  165 . In the embodiment of FIGS. 26A and 26B, the actuator  141  and its plunger  148  are operated in the same fashion as shown and described herein relative to FIGS. 24 and 25. However, in FIGS. 26A and 26B, the plunger  148  simply extends over the top of cap  161  preventing it from opening. In FIG. 26A, when the plunger  148  is retracted as indicated by arrow  167 , cap  161  can be opened. 
     In the embodiment of FIG. 27, apparatus  128 C includes cap  168  which is internally threaded and having threads that engage the external threads of a filler neck on fuel tank  139 . As with the embodiment of FIGS. 26A and 26B, the embodiment of FIG. 27 extends the plunger  148  into a locking position to prevent a user from unthreading the cap  168  from its filler neck until the engine  11  has cooled below the desired temperature. 
     In FIGS. 28A and 28B, another embodiment of the apparatus of the present invention is shown, designated as  128 D. In FIGS. 28A and 28B, the plunger  148  carries an enlarged end portion  169  having a rubber or resilient contact member  170 . The rubber contact member  170  engages ribbed cap  171 . The ribs  172  are sharp so that they are gripped by the resilient or rubber contact member  170  that conforms generally to the ribs  172 . 
     The contact member  170  has a concave surface  173  that generally fits the contour of the external surface of the cap  171 . In FIG. 28B, arrow  174  indicates movement of plunger  148  to an unlocked position. 
     In the embodiment of FIG. 29, the apparatus  128 E includes a timer arrangement used in concert with the actuator  141  of FIGS. 23A and 23B for locking fuel cap  140  until the temperature of the engine block  129 A of engine  129  has cooled. In FIG. 29, a timer  175  locks the cap  140  until a sufficient amount of time has lapsed (2-5 minutes) so that the cap can be removed without a danger of explosion or fire. In FIG. 29, key switch  176  has key  177  for operating engine ignition and timer  175 . When key  177  is turned to the “on” position, a timer circuit activates actuator  141  so that plunger  148  is moved to the locked position, and remains locked as long as the key is in the on position. When key  177  is turned to the “off” position, timer  175  is activated to keep plunger in locked position. After a desired time interval of two to five minutes, for example, timer  175  halts the flow of electricity from battery  132  to actuator  175  so that its return spring  150  (see FIGS. 23A-23B) moves the plunger  148  to the unlocked position shown in FIG.  29 . Wire cables  178 - 182  are shown in FIG. 9 interfacing battery  132 , lock  176 , timer and actuator  141 . 
     In FIG. 30, the apparatus  128  F includes plunger  183  that is manually operated using heat sensitive coil  187 . Plunger  183  is mounted in switch housing  184 . Plunger  183  is attached to cable  185 . The cable  185  extends out of the switch housing  184  to engage radial arm  188  of coil  187 . Coil housing  186  contains coil  187  and also provides a stop for limiting movement of free end  187  of radial arm  188 . Arrow  189  in FIG. 30 indicates the movement of radial arm  188  and its free end  190  between a locking position shown in hard lines in FIG.  30  and an unlocked position shown in phantom lines in FIG.  30 . 
     In FIG. 9, the heat indicated by waves  160  causes coil  187  to expand to the locked position shown in FIG.  30 . When the heat of the engine reduces to an acceptable temperature level, coil  187  cools and contracts, moving radial arm  188  to the unlocked position shown in phantom lines in FIG. 30, and pulling cable  185  and plunger  183  with it. 
     PARTS LIST 
     The following is a list of parts and materials suitable for use in the present invention: 
     
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 NUMBER 
                 PART 
               
               
                   
                   
               
             
             
               
                   
                  10 
                 safety fuel tank and cap apparatus 
               
               
                   
                  11 
                 magnetoelectric generator 
               
               
                   
                  12 
                 pull cord starter rope 
               
               
                   
                  13 
                 electric cable 
               
               
                   
                  14 
                 fuel tank 
               
               
                   
                  15 
                 upper surface 
               
               
                   
                  16 
                 cylindrically shaped flange 
               
               
                   
                  16A 
                 cylindrically shaped flange 
               
               
                   
                  17 
                 external thread 
               
               
                   
                  18 
                 opening 
               
               
                   
                  19 
                 filler cap 
               
               
                   
                  19A 
                 filler cap 
               
               
                   
                  19B 
                 filler cap 
               
               
                   
                  19C 
                 hinged filler cap 
               
               
                   
                  20 
                 annular skirt 
               
               
                   
                  20A 
                 inner annular surface 
               
               
                   
                  20B 
                 outer annular surface 
               
               
                   
                  21 
                 top 
               
               
                   
                  22 
                 handle 
               
               
                   
                  23 
                 internal thread 
               
               
                   
                  24 
                 vent 
               
               
                   
                  25 
                 magnet 
               
               
                   
                  26 
                 outer end 
               
               
                   
                  27 
                 inner end 
               
               
                   
                  28 
                 switch 
               
               
                   
                  29A 
                 lead 
               
               
                   
                  29B 
                 lead 
               
               
                   
                  30 
                 ground 
               
               
                   
                  31 
                 arrow 
               
               
                   
                  32 
                 arrow 
               
               
                   
                  33 
                 spring 
               
               
                   
                  34 
                 contact plate 
               
               
                   
                  35 
                 contact point 
               
               
                   
                  36 
                 contact point 
               
               
                   
                  37 
                 annular edge 
               
               
                   
                  38 
                 circular cap 
               
               
                   
                  39 
                 annular skirt 
               
               
                   
                  40 
                 safety fuel tank and cap apparatus 
               
               
                   
                  41 
                 cap 
               
               
                   
                  42 
                 handle 
               
               
                   
                  43 
                 vent 
               
               
                   
                  44 
                 annular skirt 
               
               
                   
                  45 
                 top 
               
               
                   
                  46 
                 appendage 
               
               
                   
                  47 
                 undersurface 
               
               
                   
                  48 
                 button switch 
               
               
                   
                  49 
                 contact 
               
               
                   
                  50 
                 contact 
               
               
                   
                  51 
                 spring 
               
               
                   
                  52 
                 contact plate 
               
               
                   
                  53 
                 switch bottom 
               
               
                   
                  54 
                 arrow 
               
               
                   
                  55 
                 arrow 
               
               
                   
                  56 
                 safety fuel tank and cap apparatus 
               
               
                   
                  57 
                 filler cap 
               
               
                   
                  58 
                 annular skirt 
               
               
                   
                  59 
                 top 
               
               
                   
                  60 
                 handle 
               
               
                   
                  61 
                 switch 
               
               
                   
                  62 
                 switch housing 
               
               
                   
                  63 
                 electric eye 
               
               
                   
                  64 
                 arrow 
               
               
                   
                  65 
                 reflector 
               
               
                   
                  66 
                 opening 
               
               
                   
                  67 
                 annular rib 
               
               
                   
                  68 
                 safety fuel tank and cap apparatus 
               
               
                   
                  69 
                 micro switch 
               
               
                   
                  70 
                 switch arm 
               
               
                   
                  71 
                 ring 
               
               
                   
                  72 
                 opening 
               
               
                   
                  73 
                 beam 
               
               
                   
                  74 
                 filler cap 
               
               
                   
                  75 
                 top 
               
               
                   
                  76 
                 annular skirt 
               
               
                   
                  77 
                 handle 
               
               
                   
                  78 
                 shroud 
               
               
                   
                  79 
                 cover 
               
               
                   
                  80 
                 bolt 
               
               
                   
                  81 
                 arrow 
               
               
                   
                  82 
                 fuel line 
               
               
                   
                  83 
                 weed trimmer 
               
               
                   
                  84 
                 annular surface 
               
               
                   
                  85 
                 frame 
               
               
                   
                  86 
                 laterally extending projection 
               
               
                   
                  87 
                 laterally extending projection 
               
               
                   
                  88 
                 outer annular surface 
               
               
                   
                  89 
                 annular edge 
               
               
                   
                  90 
                 circular cap 
               
               
                   
                  91 
                 outer annular surface 
               
               
                   
                  92 
                 annular edge 
               
               
                   
                  93 
                 laterally extending projection 
               
               
                   
                  94 
                 laterally extending projection 
               
               
                   
                  95 
                 gasket seal 
               
               
                   
                  96 
                 hinge 
               
               
                   
                  97 
                 spring loaded cap member 
               
               
                   
                  98 
                 spring loaded latch 
               
               
                   
                  99 
                 pivot 
               
               
                   
                 100 
                 sear 
               
               
                   
                 101 
                 flat top 
               
               
                   
                 102 
                 skirt 
               
               
                   
                 103 
                 outer surface 
               
               
                   
                 104 
                 arrow 
               
               
                   
                 105 
                 safety fuel tank and cap apparatus 
               
               
                   
                 106 
                 fuel tank 
               
               
                   
                 107 
                 upper surface 
               
               
                   
                 108 
                 fuel filler neck 
               
               
                   
                 109 
                 side wall 
               
               
                   
                 110 
                 annular shoulder 
               
               
                   
                 111 
                 adaptor 
               
               
                   
                 112 
                 filler neck 
               
               
                   
                 113 
                 side wall 
               
               
                   
                 114 
                 annular shoulder 
               
               
                   
                 115 
                 slot 
               
               
                   
                 116 
                 slot 
               
               
                   
                 117 
                 micro switch 
               
               
                   
                 118 
                 arm 
               
               
                   
                 119 
                 projection 
               
               
                   
                 120 
                 plunger type switch 
               
               
                   
                 121 
                 plunger 
               
               
                   
                 122 
                 housing 
               
               
                   
                 123 
                 ignition system 
               
               
                   
                 124 
                 key switch 
               
               
                   
                 125 
                 switch 
               
               
                   
                 126 
                 lead 
               
               
                   
                 127 
                 ground 
               
               
                   
                 P 
                 projection 
               
               
                   
                 S 
                 switch 
               
               
                   
                 E 
                 engine 
               
               
                   
                 128 
                 safety fuel tank and cap apparatus 
               
               
                   
                 128A 
                 safety fuel tank and cap apparatus 
               
               
                   
                 128B 
                 safety fuel tank and cap apparatus 
               
               
                   
                 128C 
                 safety fuel tank and cap apparatus 
               
               
                   
                 128D 
                 safety fuel tank and cap apparatus 
               
               
                   
                 128E 
                 safety fuel tank and cap apparatus 
               
               
                   
                 128F 
                 safety fuel tank and cap apparatus 
               
               
                   
                 129 
                 engine 
               
               
                   
                 129A 
                 engine block 
               
               
                   
                 130 
                 starter 
               
               
                   
                 131 
                 starter solenoid 
               
               
                   
                 132 
                 battery 
               
               
                   
                 133 
                 ground 
               
               
                   
                 134 
                 battery cable 
               
               
                   
                 135 
                 battery cable 
               
               
                   
                 136 
                 battery cable 
               
               
                   
                 137 
                 heat sensor 
               
               
                   
                 138 
                 cable 
               
               
                   
                 139 
                 fuel tank 
               
               
                   
                 140 
                 fuel cap 
               
               
                   
                 141 
                 actuator 
               
               
                   
                 142 
                 actuator housing 
               
               
                   
                 143 
                 housing interior 
               
               
                   
                 144 
                 wire lead 
               
               
                   
                 145 
                 terminal 
               
               
                   
                 146 
                 coil 
               
               
                   
                 147 
                 wire lead 
               
               
                   
                 148 
                 plunger 
               
               
                   
                 149 
                 flange 
               
               
                   
                 150 
                 spring 
               
               
                   
                 151 
                 anchor plate 
               
               
                   
                 152 
                 arrow 
               
               
                   
                 153 
                 recess 
               
               
                   
                 154 
                 projecting end 
               
               
                   
                 155 
                 switch 
               
               
                   
                 156 
                 coil 
               
               
                   
                 157 
                 contact bar 
               
               
                   
                 158 
                 terminal 
               
               
                   
                 159 
                 terminal 
               
               
                   
                 160 
                 heat 
               
               
                   
                 161 
                 cap 
               
               
                   
                 162 
                 hinge 
               
               
                   
                 163 
                 latch 
               
               
                   
                 164 
                 arrow 
               
               
                   
                 165 
                 filler neck 
               
               
                   
                 166 
                 opening 
               
               
                   
                 167 
                 arrow 
               
               
                   
                 168 
                 cap 
               
               
                   
                 169 
                 enlarged end portion 
               
               
                   
                 170 
                 rubber contact member 
               
               
                   
                 171 
                 ribbed cap 
               
               
                   
                 172 
                 rib 
               
               
                   
                 173 
                 concave surface 
               
               
                   
                 174 
                 arrow 
               
               
                   
                 175 
                 timer 
               
               
                   
                 176 
                 key switch 
               
               
                   
                 177 
                 key 
               
               
                   
                 178 
                 wire cable 
               
               
                   
                 179 
                 wire cable 
               
               
                   
                 180 
                 wire cable 
               
               
                   
                 181 
                 wire cable 
               
               
                   
                 182 
                 wire cable 
               
               
                   
                 183 
                 plunger 
               
               
                   
                 184 
                 plunger housing 
               
               
                   
                 185 
                 cable 
               
               
                   
                 186 
                 coil housing 
               
               
                   
                 187 
                 heat sensitive coil/bi-metal spring 
               
               
                   
                 188 
                 radial arm 
               
               
                   
                 189 
                 arrow 
               
               
                   
                 190 
                 free end 
               
               
                   
                 191 
                 stop position 
               
               
                   
                   
               
             
          
         
       
     
     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. 
     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.