Patent Publication Number: US-6220853-B1

Title: Disposable childproof lighter

Description:
BACKGROUND OF THE PRESENT INVENTION 
     1. Field of Invention 
     The present invention relates to disposable lighter, and more particularly to a disposable childproof lighter wherein the driving caps are normally disengaged with the gear wheels which drive the striker wheel to ignite, so as to prevent the disposable lighter from being ignited accidentally or by children. 
     2. Description of Related Arts 
     Nowadays, both U.S. government and U.S. Consumer Product Safety Commission demand a safety device in every cigarette lighter including the disposable lighter to prevent unwanted ignition accidentally or by a child. As it is known that the disposable lighter is common and relatively cheap, it is impossible to incorporate with expensive and complex safety device that highly increases the cost of the disposable lighter. In order to minimize the manufacturing cost of the disposable lighter employed with safety device, one of the most common disposable safety lighter is the driving wheel type disposable safety lighter. This type of disposable lighter comprises a pair of driving wheels for driving the striker wheel to rotate in order to generate sparks, wherein the driving wheels normally run idle when the driving wheels are physically disengaged with the striker wheel. 
     For example, U.S. Pat. No. 5,547,370, owned by Hwang, discloses a wheel axle mounted between two upright supports at the top of a butane wheel, two driving wheels mounted around the wheel axle and disposed in contact with a spring-supported flint below and turned by the driving wheels through the wheel axle to strike the spring-supported flint in producing sparks. The wheel axle is made of polygonal cross section, having two round rods at two opposite ends loosely inserted into a respective axle hole on each upright support so as to ensure a better connection between the striker wheel and the wheel axle. 
     Another example is U.S. Pat. No. 5,997,281, owned by Lei discloses two side thumb-wheel each having a circular shallow indentation are respectively mounted on two sides of a friction thumb-wheel, wherein each circular shallow indentation has an inner diameter slightly larger that an outside diameter of the friction thumb-wheel such that the friction thumb-wheel can be inserted into the circular shallow indentation. In such arrangement, when a pressing force is applied on the two side thumb-wheels, the side thumb-wheels will engage with the friction thumb-wheel, which in turn bears against a flint to create a spark. 
     However, most of the driving wheel type disposable safety lighters, including the above two patents, still have the following drawbacks. 
     Since the dimension of the driving wheels (side thumb-wheels) are not produced precisely for minimizing the manufacturing cost of the disposable lighter, there is always a clearance between the driving wheel and the striker wheel. The clearance is supposed to provide a gap that the driving wheels can rotate loosely around the axle in such a manner the driving wheels are run idle around the axle. However, the clearance also provides a gap that the driving wheels can axially loose such that the driving wheels may not perfectly engage with the wheel axle of the striker wheel in order to provide an optimum mutual friction therebetween for ignition. Furthermore, in order to ignite the lighter, a downward force must applied on the driving wheels for engaging the striker wheel. In fact, the driving wheels are always engaged with the wheel axle of the striker wheel by gravity which acts as the downward force. In other words, the lighter, which claims as a safety lighter, may normally in a ready-to-ignite position. 
     SUMMARY OF THE PRESENT INVENTION 
     A main object of the present invention is to provide a disposable childproof lighter which prevents the lighter from being ignited accidentally or by children. 
     Another object of the present invention is to provide a disposable childproof lighter that the driving caps are rotatably held in a steady position so as to prevent any axially loose of the driving caps, for ensuring effective engagement of the driving cap to ignite the disposable childproof lighter. 
     Another object of the present invention is to provide a disposable childproof lighter wherein the driving caps are normally disengaged with the driven gear teeth, so as to prevent any unwanted ignition of the lighter. 
     Another object of the present invention is to provide a disposable childproof lighter, wherein in order to ignite the lighter, a user&#39;s thumb must apply a simple single operation on the driving caps, which includes a pressing down action and a rotating action at the same time. Therefore, children under five years old are unable to complete the igniting operation. 
     Another object of the present invention is to provide a disposable childproof lighter wherein the mechanism does not require to alter the original structural design of the disposable lighter, so as to minimize the manufacturing cost of incorporating the mechanism with every conventional disposable lighter. 
     Accordingly, in order to accomplish the above objects, the present invention provides a disposable childproof lighter, which comprises: 
     a supporting frame disposed on a gas reservoir having a valve which is actuated by a gas level pivotally mounted on the supporting frame for actuating the valve to release gas from the gas reservoir, wherein the supporting frame comprises a pair of supporting walls parallelly protruded upwardly at opposite sides of the gas level, each of the supporting walls having a supporting hole provided thereon, and 
     an ignition means, comprising: 
     a flint supported by a resilient element, 
     a striker wheel, which is rotatably mounted on the supporting frame, having a plurality of striking teeth evenly provided on an outer circumferential surface thereof, wherein the flint is supported by the resilient element to upwardly urging against a portion of the striking teeth, 
     a pair of driven gear elements for coaxially mounting the striker wheel between the two supporting walls of the supporting frame, each of the driven gear elements comprising a gear wheel having an outer circumferential surface and a support shank integrally and coaxially protruded from an inner side of the gear wheel, wherein the two support shanks, which are smaller than the two gear wheels in diameter, are coaxially mounted on two sides of the striker wheel to define two supporting gaps between the two sides of the striker wheel and the two gear wheels respectively, and the two gear wheels are respectively and rotatably mounted to the two supporting walls of the supporting frame in such a manner that the striker wheel is capable of being driven to rotate when driving the two gear wheels to rotate, and 
     a pair of driving caps, each having a circular driving cavity coaxially provided at an outer side thereof so as to define an inner side wall, each of the driving cavities having a diameter larger than that of the gear wheels of the driven gear elements, wherein a central support hole is coaxially provided at each of the inner side walls for rotatably mounting on the respective support shank of the respective driven gear element while the gear wheel of the respective driven gear element is rotatably received in the respective driving cavity, wherein the two inner side walls of the two driving caps are rotatably disposed in the two supporting gaps respectively so as to hold the two driving caps in a rotatable position between the striker wheel and the two driven gear elements respectively, wherein each of the driving cavities has an inner circumferential surface, wherein the two driving caps are arranged free to rotate normally with respect to the two driven gear elements unless a downward force is intentionally applied on the driving caps while rotating the driving caps to drive the driven gear elements and the striker wheel to rotate to strike against the flint to produce sparks. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a disposable childproof lighter according to a preferred embodiment of the present invention. 
     FIG. 2 is a sectional view of the ignition means of the disposable childproof lighter according to the above preferred embodiment of the present invention. 
     FIG. 3 is an exploded perspective view of the ignition means of the disposable childproof lighter according to the above preferred embodiment of the present invention. 
     FIG. 4A is a sectional side view of the ignition means of the disposable childproof lighter according to the above preferred embodiment of the present invention. 
     FIG. 4B is a sectional side view of the ignition means of the disposable childproof lighter according to the above preferred embodiment of the present invention, illustrating the engagement between the driven gear element and the driving cap. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 to  4  of the drawings, the disposable childproof lighter  1  according to a preferred embodiment of the present invention is illustrated, wherein the disposable childproof lighter  1  comprises a supporting frame  10  and an ignition means  20 . 
     The supporting frame  10  is mounted on a gas reservoir  11  which has a gas valve  12  upwardly extended from the supporting frame  10 . The gas valve  12  is actuated by a gas level  13  to release gas from the gas reservoir  11 . The supporting frame  10  comprises a pair of supporting walls  14  parallelly protruded at opposite sides of the gas level  13  and the gas level  13  is pivotally mounted between the two supporting walls  14  of the supporting frame  10 . Each of the supporting walls  14  has a supporting hole  141  provided thereon. A windshield  15  is detachably mounted on the supporting frame  10  to encircle the gas valve  12 . 
     The ignition means  20  comprises a flint  21  supported by a resilient element  22  and a striker wheel  23 . The flint  21  and the resilient element  22  are received in a flint housing  16  provided between the two supporting walls  14  of the supporting frame  10 . The striker wheel  23 , which is a hollow wheel body having a central axial hole  230 , is rotatably mounted between the two supporting walls  14  of the supporting frame  10 . An outer circumferential surface of the striker wheel  23  has a plurality of striking teeth  231  evenly provided thereon. 
     The flint  21  is supported by the resilient element  22  to upwardly urging against a portion of the striking teeth  231 . In order to ignite the lighter  1 , sparks must be produced and directed toward the gas valve  12  by driving the striking teeth  231  to strike against the flint  21 . 
     The ignition means  20  further comprises a pair of driven gear elements  30  for coaxially mounting the striker wheel  23  between the two supporting walls  14  of the supporting frame  10 . Each of the driven gear elements  30  comprises a gear wheel  31  having an outer circumferential surface  310 , and a support shank  33  integrally and coaxially protruded from an inner side of the gear wheel  31 . The outer circumferential surface  310  can be a coarse surface. According to the preferred embodiment, a plurality of driven gear teeth  311  spacedly provided on the outer circumferential surface  310 . 
     Each of the support shank  33  comprises a wheel axle  331  and a support wheel  332  which is integrally and coaxially positioned between the gear wheel  31  and the wheel axle  331 . 
     The two wheel axles  331 , which are smaller than the two gear wheels  31  in diameter, are coaxially fitted into two ends of the central axial hole  230  of the striker wheel  23  respectively. Each of the two support wheels  332  has a diameter slightly larger than the two wheel axles  331 , so that when the two wheel axles  331  are fully plugged into the two ends of the central axial hole  230  of the striker wheel  23 , two supporting gaps  24  will be exactly defined between the two sides of the striker wheel  23  and the two gear wheels  31  respectively. 
     The two gear wheels  31  are respectively and rotatably mounted to the two supporting walls  14  of the supporting frame  10  in such a manner that the striker wheel is capable of being driven to rotate when driving the two gear wheels  31  to rotate. According to the preferred embodiment of the present invention, each of the driven gear elements  30  further comprises a supporting shaft  32 . The two supporting shafts  32  are rotatably inserted into the supporting holes  141  of the two supporting walls  14  respectively. 
     Accordingly, a total thickness of the gear wheel  31  and the support wheel  332  is preferred to be equal to or slightly smaller than a distance between the respective supporting wall  14  and the opposing side of the striker wheel  23 . 
     The ignition means  20  further comprises a pair of driving caps  40  each having a thickness equal to the total thickness of the gear wheel  31  and the support wheel  332 . A circular driving cavity  41  is coaxially provided at an outer side thereof so as to define an inner side wall  401 . Each of the driving cavities  41  has a diameter larger than that of the gear wheels  31  of the driven gear elements  30 , wherein a central support hole  402  is coaxially provided at each of the inner side walls  401  for rotatably mounting on the support wheel  332  of the support shank  33  of the respective driven gear element  30  while the gear wheel  31  of the respective driven gear element  30  is rotatably received in the respective driving cavity  41 . 
     As shown in FIGS. 2 and 3, the width of the each of the supporting gaps  24 , i.e. the width of the support wheel  332 , should be equal to or slight larger than the thickness of the side wall  401  of each driving cap  40 . Accordingly, as shown in FIGS. 3 and 4, the two inner side walls  401  of the two driving caps  40  are rotatably disposed in the two supporting gaps  24  respectively so as to hold the two driving caps  40  in a rotatable position, wherein each of the driving cavities  41  has a plurality of driving teeth  411  are spacedly provided on an inner circumferential surface  412  of the respective driving cavities  41  in such a manner that the two driving caps  40  are normally disengaged with the two driven gear elements  30  to enable free rotation of the two driving caps  40  unless a downward force is intentionally applied on the driving caps  40  while rotating the driving caps  40  to drive the driven gear elements  30  and the striker wheel  23  to rotate to strike against the flint  21  to produce sparks. 
     Since the diameter of each of the driving cavities  41  is larger than the diameter of the respective gear wheel  31  received therein, the two driving caps  40  can be rotated to idle with respect to the two driven gear elements  30 . In other words, the two driving caps  40  are normally disengaged with the driven gear elements  30  unless a relatively large force is applied to the two driving caps  40  by an adult to downwardly press the two driving caps  40  against the two gear wheels  31  of the two driven gear elements  30  in order to drive the driven gear elements  30  and the striker wheel  23  to rotate. Since a minor does not have enough power to press down and rotate the driving caps  40  at the same time, the arrangement of the two driven gear elements  30  and the two driving caps  40  can substantially prevent a minor from driving the striker wheel  23  to rotate and ignite the lighter. 
     Substantially, the driving teeth  411  provided on the inner circumferential surfaces  412  of the driving cavities  41  of the two driving caps  40  can be smaller teeth rendering the inner circumferential surfaces  412  to become coarse surfaces that can provide great friction when the two inner circumferential surface  412  are pressed against the driven gear teeth  311  provided on the outer circumferential surfaces of the two gear wheels  31 . Alternatively, the driving teeth  411  of the two driving caps  40  can also be arranged to engage with a top portion of the driven gear teeth  311  of the gear wheels  31  of the two driven gear elements  30  when the two driving caps  40  are downwardly pressed down for ensuring the driven gear elements  30  to be driven to rotate by the driving caps  40  to drive the striker wheel  23  to strike against the flint  21  to generate sparks towards the gas valve  12 . 
     Each of the driving caps  40  is not only rotatably mounted on the respective driven gear element  30 , the inner side wall  401  of each driving cap  40  is also sandwiched between striker wheel  23  and the gear wheel  31  of the respective driven gear element  30 . In other words, the driving caps  40  are rotatably held between the striker wheel  23  and the two driven gear elements  30  respectively that can prevent any unwanted axial loose of the driving cap  40  for ensuring effective engagement between the driving caps  40  and the driven gear elements  30  when the downward force is applied to the driving caps  40 . In fact, during assemble, the two driving caps  40  must be coaxially aligned at two sides of the striker wheel  23  with the two driving cavities  41  thereof facing out, and then by plugging the two wheel axle  331  of the two support shank  33  of the two driven gear elements  30  into the two ends of the central axial hole  230  of the striker wheel  30  until the two gear wheels  31  of the two driven gear elements  30  are received in the two driving cavities  41  respectively. 
     Therefore, as shown in FIG. 2, the striker wheel  23 , the two driving caps  40  and the two driven gear elements  30  are combined to form a single wheel unit with the two driving caps  40  being arranged free to rotate. The two driving caps  40  can not be detached from the wheel unit unless separating the two driven gear elements  30  from the striker wheel. Accordingly, the igniting means  20  is in a safety condition normally, wherein each of the driving caps  40  can be freely rotated around the gear wheel  31  and the support wheel  332  of the respective driven gear elements  30  respectively. 
     Referring to FIG. 4A, the driven gear teeth  311  are spacedly and outwardly protruded from the outer circumferential surface of the gear wheel  31  of the each of the driven gear elements  30 . Correspondingly, the driving teeth  411  of the driving caps  40  can also be arranged spacedly with respect to the driven gear teeth  311 , so that when the driving caps  40  are pressed down by a downward force, one of the driving teeth  411  of each of the driving caps  40  will be pressed to engage with at least one of the upper driven gear teeth  311  of the respective gear wheels  31  for driving the driven gear elements  30  and the striker wheel  23  to rotate, as shown in FIG.  4 B. In order to provide a better contact between the driving caps  40  and the adult&#39;s thumb, a knurling surface  42  is provided on an outer circumferential surface of each driving cap  40  such that the adult&#39;s thumb can easily drive the driving caps  40  to rotate. 
     Accordingly, children under five years old are not strong enough to press down the driving caps  40  to generate friction between the driving caps and the driven gear elements  30  or to maintain the engagement between the driving teeth  411  and the driven gear teeth  311  while turning the driving caps  40 . However, an adult can easily “press and turn” the driving caps  40  to finish the ignition operation.