Patent Publication Number: US-6669465-B2

Title: Safety lock for piezoelectric lighter

Description:
BACKGROUND OF THE PRESENT INVENTION 
     1. Field of Invention 
     The present invention relates to a lighter, and more particularly to a piezoelectric lighter which comprises a safety lock for preventing the lighter from being accidentally or undesirably ignited, especially by children. 
     2. Description of Related Arts 
     For protecting the safety and benefit of children, the U.S. Consumer Product Safety Commission imposed an important regulation that “Child below 5 years old cannot light the lighter”. Some of the piezoelectric lighters, such as U.S. Pat. Nos. 4,786,248, 4,859,172, 5,240,408, 5,368,473, and 5,462,432, each provides a switching mechanism for rendering the piezoelectric lighter child resistant. Each switching mechanism provides a switch member requiring the adult user to turn on before permitting an thumb-operated piezoelectric unit to be depressed to lift a gas pipe to open a gas release valve to emit gas and to generate sparks at the same time to ignite the emitted gas. 
     However, such conventional piezoelectric lighters with switching mechanism also bear the drawbacks as follows: 
     1. Some switching mechanisms require the piezoelectric lighter to alter its structure in order to equip with the switch member. Or, numerous of additional elements of the switching mechanism are required to incorporate with the traditional piezoelectric lighter for ensuring the safety feature thereof. Such costly switching mechanism not only increases the cost of the lighter, but also increases the manufacturing procedures of the lighter. 
     2. If the user forgets to turn off the switch member to its locking position the piezoelectric lighter is already to ignite by any child. In other words such switch-type safety piezoelectric lighter can provide safety function if and only if the adult user remembers to operate an additional turning off action to re-lock the switching mechanism of the piezoelectric lighter again. Most users may even intentionally skip this re-locking operation. 
     In fact, the conventional switching mechanism of the piezoelectric lighter is a manual lock only but can not be classified as a safety lock because a real safety lighter should normally be locked, that is the piezoelectric lighter should automatically re-lock after each ignition operation, so as to prevent the children from igniting the lighter anytime, or to prevent the lighter from accidentally or unintentionally be ignited by the user. 
     SUMMARY OF THE PRESENT INVENTION 
     A main object of the present invention is to provide a safety lock for piezoelectric lighter for preventing accidental or undesirable ignition of the piezoelectric lighter. 
     Another object of the present invention is to provide a piezoelectric lighter incorporated with a safety lock wherein the lighter can only be ignited by applying simultaneous inward and downward forces to the ignition button in one continuous action. That is, accidental or undesirable ignition would be avoided because of the relatively indirect ignition mechanism. 
     Another object of the present invention is to provide a safety lock for a piezoelectric lighter which does not alter the original structural design of conventional piezoelectric lighter, thus to minimize the manufacturing cost of the piezoelectric lighter. 
     Another object of the present invention is to provide a safety lock for a piezoelectric lighter, which can automatically return to a locking condition after each ignition operation, so as to prevent any lighting operation of the piezoelectric unit by locking up the downward movement of the pusher cap. 
     Accordingly, in order to accomplish the above objects the present invention provides a piezoelectric lighter, which comprises: 
     a lighter casing having an internal fuel chamber for storing liquefied fuel; 
     a supporting frame which is supported on a ceiling of the lighter casing having a pusher cavity, an ignition cavity, and a pair of supporting walls upwardly extended from two opposite sides of the supporting frame, wherein each of the supporting walls has a longitudinal sliding groove formed thereon; 
     an ignition system which comprises a gas-emitting nozzle received in the ignition cavity of the supporting frame and communicated with the internal fuel chamber of the lighter casing, and a piezoelectric unit disposed in said lighter casing for generating sparks; 
     an ignition button which is slidably disposed in the pusher cavity of the supporting frame in such a manner that when the ignition button is depressed downwardly, the gas emitting nozzle is lifted up for releasing gaseous fuel, and the piezoelectric unit is arranged to generate sparks for igniting the fuel released from the gas emitting nozzle; and 
     a safety lock, comprising a locking member which is slidably mounted on the ignition button and comprises a pair of guiding arms for switching between a locked state and an unlocked state of the lighter, wherein in the locked state, the pair of guiding arms are adapted to bias against top ends of the two sliding grooves respectively for restricting a downward movement of the ignition button, and in the unlocked state, the pair of guiding arms are adapted to move forwardly from the locked position and aligned with the two sliding grooves respectively, so that the pair of guiding arms and therefore the ignition button are capable of sliding downwardly when a depressive force is applied to the ignition button. 
     In order to ignite the lighter of the present invention one has to apply both the inward and downward forces simultaneously to the safety lock and the ignition button respectively in one action. At the same time the ignition button is being pressed down, the gas-emitting nozzle is lifted up for releasing gaseous fuel. When the ignition button is depressed to a certain ignition point, sparks are generated by the piezoelectric unit to ignite the fuel emitted from the gas-emitting nozzle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a piezoelectric lighter incorporated with a safety lock according to a preferred embodiment of the present invention. 
     FIG. 2 is an exploded isometric view of the piezoelectric lighter incorporated with a safety lock according to a preferred embodiment of the present invention. 
     FIG. 3 is a sectional side view of the piezoelectric lighter incorporated with a safety lock according to a preferred embodiment of the present invention, illustrating the lighter is in normal locked state. 
     FIG. 4 is a sectional side view of the piezoelectric lighter incorporated with a safety lock according to a preferred embodiment of the present invention, illustrating the lighter is in unlocked state. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 to  4  of the drawings, a piezoelectric lighter incorporated with a safety lock according to a preferred embodiment of the present invention is illustrated. The piezoelectric lighter  1  comprises a lighter casing  11 , a supporting frame  10 , an ignition system  20  and a safety lock  30  for preventing the piezoelectric lighter  1  from accidentally ignited. 
     The lighter casing  11  comprises an internal fuel chamber  110  for storing liquefied fuel. The internal fuel chamber  110  has an opening at its top end for communicating with the ignition system  20 , so that the fuel inside the internal fuel chamber  110  can be supplied to the ignition system  20  for igniting the lighter. 
     The supporting frame  10  has an ignition cavity  111  for receiving the ignition system  20  therein and a pusher cavity  112  for supporting an ignition button  24  of the ignition system  20  therein. Essentially, the supporting frame  10  is an upwardly extruded object from a predefined shape that includes a pair of supporting walls  12  which are protruded on opposite sides of a ceiling of the supporting frame  10  respectively. 
     The ignition system  20  comprises a piezoelectric unit  21  for generating sparks to ignite the piezoelectric lighter  1 , a gas emitting nozzle  22  communicating with the internal fuel chamber  110  and controlling the amount of fuel flowing out of the internal fuel chamber  110 , a lever  23  pivotally supported by the lighter casing  11  for actuating the gas emitting nozzle  22  to release fuel from the internal fuel chamber  110 . 
     The piezoelectric unit  21  which is fitted in the lighting casing  10  comprises a movable operating part  211  extended through the pusher cavity  112  for generating piezoelectricity, an enlarged pusher head  212  provided at an upper portion of the movable operating part  211  and an ignition tip  213  which is extended from the piezoelectric unit  21  to a position adjacent to the gas emitting nozzle  22  when the gas emitting nozzle  22  is fully lifted up by the lever  23  to release gaseous fuel. In which, a depressible end  231  of the lever  23  is extended underneath the pusher head  212 , so that when the movable operating part  211  is depressed downwardly from an original position to a certain ignition point, the depressible end  231  of the lever  23  is depressed downwardly by the pusher head  222  that pivotally lifts up an up-lifting end  232  of the lever to lift up the gas emitting nozzle  22  to release fuel, and, at the same time, sparks are generated at the ignition tip  213  to ignite the fuel emitted through the gas emitting nozzle  22 . Note that when the movable operating part  211  is depressed, a resilient clement inside the piezoelectric unit  21  can rebound the movable operating part  211  upwardly to its original position when the depressing force is relieved. 
     The ignition button  24  is slidably disposed in the pusher cavity  112  of the lighter casing  11  in a vertically movable manner wherein the ignition button  24  is arranged in such manner that when the ignition button  24  is depressed downwardly with respect to the lighter casing  11 , the movable operating part  211  of the piezoelectric unit  21  is depressed downwards to generate piezoelectricity. 
     As shown in FIG. 2, the ignition button  24  further comprises a pair of blocking latches  272  protruded outwardly and upwardly from two side walls  243  of the ignition button  24  for biasing against two L-shaped top edges  14  of two side walls of the pusher cavity  112 , so as to retain the ignition button  24  in the normal upper position and prevent the ignition button  24  being slid out of the pusher cavity  112 , especially by the pushing force of the resilient element inside the piezoelectric unit  21 . 
     According to the present invention, in order to corporate with the safety lock  30 , each of the supporting walls  12  has a vertical L-shaped sliding groove  31  formed on the inner side of the supporting wall  12  for slidably coupling the ignition button  24  with the supporting walls  12 . Moreover, the ignition button  24 , which has a U-shaped cross section defining two front walls  241  and a top panel  240 , further comprises a pair of L-shaped guiding members  301  frontwardly protruded from two front walls  241  of the ignition button  24  and has a pair of slider slots  32  transversely formed on a top portion of the top panel  240 . 
     The pair of guiding members  301  is adapted to slide inside the pair of L-shaped sliding grooves  31  of the supporting frame  10  respectively. Such an arrangement allows the ignition button  24  to vertically slide in the pusher cavity  112  of the supporting frame  10 . 
     The safety lock  30  comprises a locking member  33  slidably mounted on the top panel  240  of the ignition button  24 . The locking member  33  comprises a pair of L-shaped guiding arms  331  slidably penetrated through the two slider slots  32  and arranged to be driven from a normal locking position to an unlocked position. Each of the guiding arms  331  has a locker lip  332  sidewardly projected therefrom. 
     The safety lock  30  further comprises a resilient element  34  which is essentially a compressive spring mounted between the locking member  33  and the ignition button  24 , for applying an urging pressure against the locking member  33  so as to normally retain the locking member  33  at the normal locked position. In normal locked state as shown in FIG. 3, the locker lips  332  of the two L-shaped guiding arms  331  are biased against two top edges of the two supporting walls  12  respectively for blocking the ignition button from being slid downwardly. 
     In contrast, when the piezoelectric lighter  1  is in the unlocked state as shown in FIG. 4, the locking member  33  is pushed inwardly to compress the resilient element  34  in order for the two locker lips  332  of the two L-shaped guiding arms  331  to be aligned with the two L-shaped sliding grooves  12  respectively. The two guiding arms  331  are then ready to be depressed downwardly to the pusher cavity  112  along the two sliding grooves  31 . 
     According to the preferred embodiment, a locker base  320  is upwardly protruded from a front portion of the top panel  240  of the ignition button  24  and the pair of the slider slots  32  is parallelly provided through the locker base  320 . Since the pair of guiding arms is ‘L’ in shape, a rear surface  333  of the locker lip  332  of each of the guiding arms  33  will bias against a front surface  321  the locker base  320  when the inwardly compressive force is relieved and the resilient element  34  restores to its original shape. Therefore, no further backward movement is allowed and the locking member  33  is retained in position. 
     As shown in FIG. 2 of the drawings, the safety lock  30  further comprises means for retaining a linear movement of the locking member  33 , which comprises at least an elongated guider rib  36  downwardly protruded from a bottom surface of the locking member  33 , wherein at least an elongated guiding groove  35  is provided on the top panel  240  of the ignition button  24 , wherein the guider rib  36  is arranged to slidably mounted on the guiding groove  35  so as to ensure that the locking member  33  can be slid smoothly on the top panel  240  of the ignition button  24 . Furthermore, two spring holders  37  are protruded from the locking member  33  and the locker base  320  respectively for securely supporting the resilient element  34  in position. 
     In order to ignite the piezoelectric lighter of the present invention, one has to unlock the safety lock  30  by applying an inward force to the locking member  33  to compress the resilient element  34  until the two guiding arms  331  are aligned right above the two sliding grooves  25  respectively. Then, a depressing force has to be simultaneously applied to the top panel  240  of the ignition button  24  for depressing the movable operating part  211  of the piezoelectric unit  21 . At the same time the ignition button  24  is being pressed down, the pusher head  212  of the piezoelectric unit  21  depresses the depressible end  231  of the lever  23 , and thus lifts up the up-lifting end  232  of the lever  23  to lift up the gas emitting nozzle  22  to release fuel. As a result, the originally liquefied and compressed fuel is being released through the gas emitting nozzle  22 . When the movable operating part  211  of the piezoelectric unit  21  is depressed to a certain ignition point, sparks are generated at the ignition tip  213  to ignite the gaseous fuel emitting from the gas emitting nozzle  22 . 
     Note that, for the sake of convenience and simple operations, a stopper edge  38  is formed on a rear portion of the locking member  33 , wherein when the locking member  33  is pushed inwards until the stopper edge  38  biases against a rear surface  322  of the locker base  320 , the two guiding arms  331  are fittingly aligned with the two L-shaped sliding grooves  31  respectively. In other words, a user only needs to apply an inward force to the locking member  33  until no movement of the locking member is observed, the user is then ready to press down the ignition button  24  to ignite the lighter. Note that all the above-mentioned ignition mechanism can be accomplished in one action. 
     After ignition, when all the depressing and inward force is relieved, the ignition button  24  is pushed upwardly by the resilient element of the piezoelectric unit  21 , and such upward motion should be stopped by the two L-shaped stoppers  272  by biasing against the two blocking latches  14 . Meanwhile, the locking member  33  is pushed outwardly by the restoring force of the resilient element  34 . The outward motion will then blocked by the front surface of the locker  53 . At this point, the piezoelectric lighter of the present invention is restored back to the normal locked state to prevent any downwardly movement of the ignition button  24 . It is important to stress that the above piezoelectric lighter can in effect automatically restored to the locked state after an ignition is completed and the depressing force of the user is relieved, therefore preventing the lighter from accidentally or undesirably ignited.