Patent Publication Number: US-8109760-B2

Title: Ignitor safety interlock and torch

Description:
FIELD OF THE INVENTION 
     The present invention relates to hand-held torches and lighters having safety interlocked ignitor, in particular torches and lighters having an ignitor interlock deactivated by the ignitor actuating finger. 
     BACKGROUND OF THE INVENTION 
     Hand-held torches and lighters are intended to be used only by one hand, the hand that holds the device. However, the added necessity of safety interlocks to prevent unwanted activation or ignition adds yet one more step, releasing the interlock, to operation of the device, in addition to holding, aiming and igniting. Often, such interlocks or safety latches require pressure or movement that is entirely separate from the movement used to ignite the flame or to hold the device, to the point of needing a separate finger or even a second hand in order to activate the torch or lighter. 
     Attempts to make release of the interlock proximal to the operation of the ignitor are still relatively clumsy, requiring compound motions of the actuating finger, such as sliding an element in a way that makes it harder to apply force or movement to the actual fuel valve and/or ignitor. In frustration, the typical user will simply interrupt their activity to again use both hands (if possible) to use the torch or lighter. 
     However, interlocks which are easier to use may also be too easy to defeat, and thus ineffective. If the lighter interlock is defeated by obvious or gross movements, then the torch or lighter may accidentally or too easily light. If the underlying application is to prevent use by children, some skill should be required, yet not overly interfere with intentional adult operation. 
     SUMMARY OF THE INVENTION 
     The torch and ignitor according to the present invention includes an ignitor and gas valve interlock located on the same part that the operator moves to activate the torch (or lighter), which is overcome by the operator by providing a tangential rolling force to the interlock as the finger is seated on a downwardly actuated ignitor. The torch ignitor and gas valve interlock according to the present invention requires a skilled, compound motion easily provided by an adult and unlikely to be imposed by accidental gross motions, without diminishing or interfering with the operator&#39;s ability to easily operate the ignitor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       These and further features of the present invention will be better understood by reading the following Detailed Description together with the Drawing, wherein 
         FIG. 1  is a perspective view of one embodiment of the interlock according to the present invention as provided on an exemplary hand-held torch at an initial, interlocked stage of use; 
         FIG. 2  is a partial perspective view of the embodiment of  FIG. 1 , with the interlock de-activated; 
         FIG. 3  is a partial perspective view of the embodiment of  FIG. 1 , with the torch gas valve and ignitor activated; 
         FIG. 4  is an exploded view of the disposition of typical torch gas valve and ignitor elements according to the embodiment of  FIG. 1 ; and 
         FIG. 4A  is a further exploded view of the interlock according to the embodiment of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT 
     The exemplary embodiment  50  of  FIG. 1  according to the present invention is typically hand  40  held and operated by the thumb  42  which comes to rest on the exemplary interlock roller  64  retained by the movable top  54 . The top (or cap)  54  moves downward into the ignitor housing  52  when the interlock  60  tab  62  does not engage the top of the housing  52 ; however, as shown in  FIG. 1 , the tab  62  does engage the top  53  of the ignitor housing, serving as a ‘detent’ and prevents the cap  54  from moving downward from thumb  42  or other forces, thus inhibiting the ability of the ignitor ( 72  of  FIG. 4 ) within the ignitor housing from operating. Additionally, the cap  54  engages a gas valve lever ( 89  of  FIG. 4 ) contained within torch head  58  to provide a flow of fuel from the fuel chamber  56  as the cap is depressed (if permitted by the location of the tab  62 ) and prior to the activation of the ignitor. 
     To operate the torch  50 , the thumb (or other operating digit) is moved over the roller  64  to cause it to rotate about an axial pin  66  longitudinally aligned with a corresponding stop axis  67  substantially perpendicular to an axis into the ignitor housing and along a corresponding longitudinal ignitor housing axis, the pin  66  being retained in the cap  54 , and rotated or rolled either by tangential motion over the roller  64  surface, by engaging the roller  64  surface and moving the thumb in an arcuate manner  44 , or a combination thereof. The pin  66  and also the roller  64  (and the surface of the cap  54  receiving the thumb) is spaced from the ignitor housing  52  and its top  53  by at least the length of the tab  62  as seen in the figures. The result thereof is shown in  FIG. 2 , wherein the tab  62  is pivoted away from the surface  55  of the cap  54  and thus removes a stop to cap  54  movement, with the greatest separation near the top of the ignitor housing  52 , in preparation for a downward movement  46  by the thumb  42 , which is now possible due to the disengagement of the tab  62  from the top of the ignitor housing  52 . 
     As shown in  FIG. 3 , the top  54  is now depressed into the ignitor housing  52  while maintaining the rotation of the roller  64  providing the tab  62  to overhang the ignitor housing  52 , releasing a fuel (gas) flow and providing ignition (e.g. an electric spark), resulting in the desired torch  50  flame. 
     A more detailed view of one embodiment of the interlock according to the present invention is shown in  FIG. 4 . The cap  54  is connected to the ignitor  72 , which in this embodiment comprises a piezoelectric spark generator which provides a high voltage pulse on wire  73  which terminates at or near the combustion region  59  within said torch head  50  where the fuel (gas in this embodiment) and any other component (e.g. air, O 2  etc. or other oxidation element for fuel) needed for combustion, mix, whereupon a spark is produced which ignites the mixture to produce the flame ( 70 ,  FIG. 3 ). The movement of the cap is typically defined by the ignitor  72  movable armature  71  which in this instance is along a vertical axis, along its length. The ignitor armature  71  is typically spring-loaded to extend out from the ignitor  72  and is receptive to compression forces which move the armature  71  into the ignitor  72  as applied to the cap  54  by a digit (e.g. thumb). At a distance along its inward travel, the armature causes the ignitor to generate the spark voltage applied to wire  73 . 
     Simultaneously with the cap  54  movement to activate the ignitor  72 , the fuel (gas) valve  80  is activated to provide a fuel flow through tubular member  84  by lever  86  having first extremities  89  engaging the cap  54  (on plate  57 ,  FIG. 4A , attached thereto) which then pivots at  88  and causes the second extremities  85  to engage and open the fuel valve  80 . In the present embodiment, the fuel valve  80  is disposed within or attached to the fuel chamber  56  or other container retained therein. The exemplary embodiment of  FIG. 4  provides a fuel valve that opens by pulling along the axis  85  away from the valve  80  by engaging the tubular member  84  (with an internal spring to urge the tubular member into the valve  80  away from the movement of the second extremities  85 ) about a radial enlargement  86  by lever  86  second extremities  85  as the cap  54  is depressed. The present embodiment further provides an adjustment of fuel flow rate when the valve  80  is open by rotating the tubular member  84  about its axis  85  with radially attached adjusting lever  83 , which typically adjust an orifice opening within the flow path of the valve  80 , or as otherwise known in the art. Additionally, the valve  80  may be temporarily locked in the open position by a movable wedge, e.g. slidable in one dimension in this embodiment, to engage the second extremities  85  of the lever  86  when in the position that causes the valve  80  to be open, and may be retracted to allow the valve  80  to again be closed. Moreover, the valve  80  may be stabilized by plate  92  affixed to a housing member (not shown) with screw  93  or other fixing device. Furthermore, the movement of the cap  54  is guided by ears  94  extending outward to engage edges  95  ( FIG. 3 ) of an aperture in head  58  of the exemplary torch embodiment  50 . 
     A further expanded view of the interlock  60  is shown in  FIG. 4A , wherein the tab  62  and roller  64  are shown as a single integrated element, which further includes a radially extending pin  65  which engages a slot (not shown) in the cap  54  to limit movement of the tab  62  away from the surface  55  ( FIG. 2 ); movement of the tab  62  to the position where it engages the ignitor housing  52 , is typically provided by merely resting against the surface  55  as urged by a spring  68  contained coaxially within the roller  64  which engages both the roller  64  and the cap  54  in the exemplary embodiment. The roller  64  is retained within the cap  54  between to appendages having apertures aligned with proper disposition of the roller  64  having spring  68  therein, adapted to receive a pin  66  therethrough. A plate  57  is attached to the cap  54  to receive the first extremities  89  of the lever  86  and provide a surface for reliable operation of the fuel valve as the cap  54  is moved downward. 
     Alternate embodiments envision other shapes of the roller as desired which provide the ability of the user to engage and rotate it about the pin  66  to move the tab  62  out of engagement of the housing  52 . Moreover, the tab is shown extending somewhat tangentially from the roller, e.g. the tab  62  plane being offset from the axis of the pin  66 , but other embodiment may include still further offset of the tab plane, or alignment thereof with the axis  67  of the pin  66  in a manner which allows the tab  62  to disengage contact with the housing ignitor  52  or any other torch  50  structure to which the tab is interposed to inhibit movement of the ignitor, the fuel valve, or both. Further modifications or substitutions by one of ordinary skill in the art are within the scope of the present invention which is not to be limited except by the claims which follow.