VALVE ACTUATOR FOR POCKET LIGHTER

Abstract: A fuel burning lighter, optionally having an adjustable flame height, comprising a supply of liquified gaseous fuel burner means communicating with the fuel supply, valve means positioned between the fuel supply and the burner means, means to provide first force to retain the valve means in a closed position to prevent gaseous fuel from passing therethrough, and means to provide second force less than the first force biasing the valve means toward an open position. The second force providing means normally provides sufficient force to move the valve means to an open position when the first force is relieved or released from acting upon the valve means.

Description: The invention concerns a fuel burning lighter comprising: a supply of liquified gaseous fuel, burner means communicating with said fuel supply; valve means positioned between said fuel supply and said burner means in a housing constituting the only passage for all fuel from said fuel supply to said burner means whereas a clearance is defined to allow said burner means to be movably disposed in said housing; said valve means comprising a valve seat and a valve seal movable between valve open and valve closed positions; a spark producing means, igniting the fuel; means to provide a closing force to retain said valve means in a closed position to prevent gaseous fuel from passing from said fuel supply to said burner means; whereas said closing force as a first force is provided by a first elastic means and is opposed by a second lesser force provided by a second elastic means biassing said valve means towards said open position, said first force being capable of being overcome by manually applied counteractive forces enabling said second force to open said valve means as soon as the net remaining closing force is removed or reduced sufficently. Such a fuel lighter, corresponding to the first part of the claim 1 is known from the US-A-3 406 000. The disclosed lighter has a cap which is forced by a strong spring in its closed position. The cap thereby acts on a rod which closes the burner valve. Between the valve and the rod, a spring is provided in order to limit the closing force acting upon the valve. This lighter is, as all other known lighters, sensible to foreign matter entering the valve mechanism. So, the invention relates to a lighter, particularly a disposable pocket lighter, wherein fuel flow is terminated when dirt, contamination, corrosion or erosion products prevent the valve mechanism of the lighter from properly operating. Most lighters sold in the world market today include a moveable burner tube for opening and closing the valve thus allowing the fuel to flow to be ignited and establish a flame. Initial thumb movement rotates a spark wheel to provide sparks for igniting the fuel at the burner tube tip. Immediately thereafter, the burner tube, which moves relative to the housing in a clearance provided therefore, is lifted by a lever arm which is operated by the force provided by the continuing thumb movement contacting a thumb portion of the lever at an end opposite the burner tube. This force on the lever acts through a pivot point to move the burner tube to an open position which allows fuel to flow from the supply to the burner tip. When the fuel arrives at the burner tube tip, it is ignited by the sparks to establish a flame. When the lighter is not used, a spring normally located under the thumb portion of the lever arm provides sufficient force to the lever arm to maintain the valve in closed position. This force is capable of withstanding exposure to the usual handling and carrying conditions without opening the valve at times when at which it is not desired. The force of the spring is generally on the order of about one pound. This force is sufficient to overcome fuel pressure which attempts to open the valve (normally about 2-4 ounces) and for providing the incremental force required to seal the valve despite the possible existence of surface imperfections of the component parts in order to achieve a reliable seal enclosure of the burner (another 2-4 ounces), as well as to overcome forces caused by minor obstructions between the movable burner tube and the housing which obstructions may cause increased friction during movement of the burner tube (estimated at approximately 4 ounces or less). As the lighter is repeatedly ignited, the action of the spark wheel on the flint generates abrasive dust particles, which may enter the clearance between the movable burner tube and the housing. Also, lint or other fabric dust from the pocket(s) of the clothing in which the lighter is carried represent a further source of dirt which can enter this clearance. The lighter will also experience various climatic conditions, both hot and cold, both in low and high humidity, as well as contact with fluids or foods, and such conditions provide a source of additional contaminants which may impede the proper movement of the burner tube between the open and closed positions. If these contaminants provide a force of an additional 4-6 ounces, then the force of the spring will be insufficient to properly close and seal the valve. It is not practical to substantially increase the force of the spring because this would impede the normal thumb operation of the lighter, making it more difficult and more cumbersome to establish a flame. Furthermore, if the spring pressure is, in fact, increased, the lever arm or other component parts can be damaged due to overstraining. Such higher forces can also cause irreversible deformation of certain component parts, particularly those of an elastomeric nature. None of the prior art lighters of which the applicant is aware have recognized the totality of this problem. Accordingly, heretofore there have been no solutions for resolving such an unrecognized problem. The present application discloses a lighter which is rendered inoperative when contaminants accumulate between the burner tube and housing sufficient to impede the proper closing and sealing of the valve so as to prevent the escape of fuel when not intended. This result is obtained by the measure that said second elastic means comprises resilient means positioned with one of its ends in tight engagement with a part of said burner means and with its other end in thight engagement with a part of the housing; the engagement areas beeing located peripheral to said burner means; said elastic means thus being dimensioned and positioned to prevent entry of foreign matter within the clearance surrounding the burner means in either position of the valve means. Further benefits and advantages of the invention will become apparent from a consideration of the following description given with reference to the accompanying drawings which specify and show preferred embodiments of the invention and wherein: FIG. 1 is a partial cross-sectional view of a lighter according to the invention with the valve in the closed position; FIG. 2 is a partial cross-sectional view of the lighter of FIG. 1 with the valve in the open position; FIG. 3a, 3b is a partial cross-sectional view of another embodiment. For the sake of clarity, all portions or parts of these lighters which are not necessary for an explanation of the invention have been omitted. The present invention avoids the disadvantages described hereinabove by providing a lighter with a valve that remains in a closed position when dirt or contamination is encountered which interferes with the proper operation of the lighter. Also, consistent and stable gas flow are achieved at reduced production costs. Referring initially to FIG. 1, there is illustrated a fuel control assembly 10 for a pocket lighter in accordance with the invention. Liquified gaseous fuel 12 is maintained in a reservoir in the lower portion of the lighter. In this embodiment, sufficient space is shown between the normal upper level 13 of the fuel and the fuel flow control member 11 located at the lower end of the fuel control assembly 10. However, such space is not essential and the liquid level can contact the fuel control mechanism directly or via a wick or dip pipe for other fuel control assemblies without affecting the closing of the valve. As one skilled in the art would realize when the valve is open, the fuel flows from the fuel tank 12, and through the fuel flow control member 11 and thereafter to the tip of the burner tube where a flame can be established ba igniting the gaseous fuel in a manner that is well known in the art. Therefore, for explaining this invention, the term "upstream" will be used to designate components or sides fo components which are first contacted by the fuel flowing from the fuel tank, while the term "downstream" will be used to designate components of sides of components which are subsequently contacted by fuel flowing to the burner tip. The fuel flow control assembly 10 includes a burner tube 21 having a gas conducting conduit 22 and gas conducting bore 15 for directing gaseous fuel to the burner tip 24. The fuel initially passes through a fuel flow control member 11 which regulates the flow of fuel to the burner tip to prevent surges and provide consistent flow thereof. Suitable fuel flow control members include those described in U.S. Patent Nos. 4,496,309 and 4,540,345, although other arrangements, with or without flame height adjustment, could be utilized without departing from the inventive features of the lighters disclosed herein. As is evident to one skilled in the art, lighters according to the invention may also utilize a dip pipe or wick. A valve seal 18 is secured to the upstream end of the burner tube 21 and is used to prevent or allow the gaseous fuel to pass from the valve bore 16 to the burner tip 24. The valve seal 18 is held in a closed position by a spring (not shown) acting on lever 26 which holds and maintains the burner tube 21 in a closed position whereby valve seal 18 covers the valve bore 16. A preferred material for the valve seal 18 is rubber and it is held securely on the end of the burner tube by crimping the ends 19 of the burner tube 21 around the valve seal 18. The burner tube 21 is preferably made of aluminium, zinc, copper or alloys thereof. Gaseous fuel from the supply 12 passes through a microporous membrane 14 thus reaching and filling the valve bore 16. When the lighter is not in operation, i.e., when fuel does not flow to the burner tip 24 to facilitate establishment and feed of a flame, valve seal 18 is maintained in a closed position in firm sealing contact relation with valve bore 16. When the burner tube 21 raises, space is provided between valve seat 17 and valve seal 18. Thus, fuel can flow from valve bore 16 around valve seal 18, thereafter through slot 20 and burner tube bore 22, to burner tip 24 and thereafter out of the lighter where a flame can be established. The amount of the clearance 23 in combination with the length L over which such clearance extends precludes passage of the gaseous fuel through the clearance space when the valve is in the open position as shown in FIG. 2. Thus, when valve seal is lifted off its seat 17, the fuel flows exclusively through the bore 22 of the burner tube 21 to its tip 24 to maintain a flame. In some instances, the elastomeric ring 36 biasing the valve seal 18 toward the open position, and the surrounding structure, may be employed to provide additional sealing capability, for example by limiting the lift-off movement of flange 28 to maintain sealing contact between the ring 36 and the underside of the flange 28. However, such additional structure is purely optional due to the already effective prevention of passage of gaseous fuel through clearance 23 as noted above. Incorporation of such optional feature will also maintain the clearance free of any contaminants such as spark wheel debris which may otherwise seek entry into the clearance 23. Such additional structure may include an upward limit stop for flange 28, preferably attached to housing 25 as shown, for example, in dotted lines as 29 in FIG. 2. Such limit stop may also be optionally incorporated in the embodiment of FIG. 3 (not shown) to present excessive lift-off movement of valve seal 18. Referring once again to FIG. 1, when lever 26 moves away from flange 28, the closing force is relieved from flange 28, burner tube 21, and valve seal 18. The burner tube 21 is lifted upward by the action of the valve opening means, illustrated in this embodiment as elastomeric ring 36, to allow gas to flow from the supply 12 to the burner tip 24. Elastomeric ring 36 is preferably made of natural or synthetic rubber having sufficient resiliency to provide an upward force on the order of about 5 ounces. It has been found that the preferred force requirements for the valve opening means should generally range from between 1/5 and 1/2, and preferably between 1/4 and 1/3, of the force provided by closing spring means 30. Thus, for lighters using other types of levers and spring arrangements, the force provided by the valve opening means or elastomeric ring 36 should be scaled accordingly. As noted above, the force provided by this ring 36 should not be greater than that necessary only to overcome the resistance to separate valve seal 18 from the valve seat 17 due to sticking, as well as the resistance due to minor manufacturing imperfections in the components of the fuel control assembly 10, along with resistance caused by minor unavoidable dirt or dust particles which are typically encountered and which find their way into the narrow clearance 23 between burner tube 21 and housing 25. The upward force on flange 28 provided by elastomeric ring 36 thus raises the valve seal 18 to the most minimum distance, which allows fuel from the supply 12 to pass to the burner tip 24 to establish a flame after ignition. Such distance is in the range of a few thousands of an inch depending upon the precision and tolerance of the component parts. This distance is provided by the movement of elastomeric ring 36 due to the relief of pressure from lever 26. This movement is due to the recovery of elastomeric ring 36 after the compressive closing force provided by the lever 26 is removed. FIG. 2 illustrates the lighter and burner tube in an open position whereby the fuel can travel from the supply 12 to the burner tip 24 for ignition and maintenance of a flame. The user's thumb provides downward movement on the thumb portion 32 of lever 36 and displaces lever end 27 a distance of about 0.1 inch, thus lifting it off the flange 28. The lever end 27 which is in communication with flange 28 of burner tube 21 does not necessarily have to encircle the burner tip 24. An open fork end at the lever end 27 is entirely suitable and in some cases preferred for ease of manufacture and assembly of the fuel control mechanism 10 of the lighter. As noted above, by minimizing the entry of dirt or other contaminants from entering into this clearance, the gumming up the lighter from abrasive contaminants and or corrosion of the tube or housing is minimized, so that the lighter can provide the longest period of acceptable operation. FIG. 3a, 3b shows an embodiment of the invention employing a cup shaped member 70 molded from elastomeric material and arranged in contacting engagement with flange 28 and housing 25 to ensure a reliable protection against contamination of the narrow clearance 23 as well as to provide a force biasing the valve toward the open position. Due to a suitable selection of the elastic properties and the shape said biasing force increases only by a relative samll amount when the burner tube 21 is moved from the open to the closed position. FIG. 3b shows the burner tube in the open position with the cup 70 relaxed, FIG. 3a shows the closed position. As noted in the drawings, the lever 26 preferably includes a fork end around burner tip 24. If desired, it is also possible to utilize a circular ring portion on the end of the lever, rather than a fork, of any other suitable means for transferring the force provided by spring 30 to flange 28 and burner tube 21. Caution must be taken to assure that the lever 26 in its most raised position (see FIG. 2) is sufficiently distant from the burner tube tip 24 so as to not be affected (i.e., burned) by the flame. In the event, however, that dirt contaminants or other impurities do enter into the clearance 23 between burner tube 22 and housing 25, the closing force provided by spring 30 would be sufficient to overcome resistance from contaminants so as to effectively close the valve. However, when the resistance caused by the contaminants exceeds the substantially lower force of the valve opening means (that is on the order of 1/4 to 1/3 of that of the closing means), the valve would be prevented from opening, thus remaining in a closed position to prevent fuel from escaping from the supply tank. While this would render the lighter inoperative, it also provides safety in that fuel cannot continue to flow or escape from the supply 12 as it would in prior art lighters when contamination builds up to a point where the spring cannot return the burner tube 21 to a closed position after the burner tube 21 has been forced to an open position by thumb pressure. Such a result cannot be achieved if the lever 26 were used to lift the burner tube 21 since the force provided by a user's thumb is much greater than the closing force provided by spring 30. Accordingly, the valve seal and burner tube 21 can be forced to an open position where it would remain, being unable to return to a properly closed position when the thumb pressure is relieved, thus allowing fuel to escape from the supply. If desired, the lighter of the invention can be provided with a nonadjustable flame or means for adjusting the flame to a predetermined flame heigt. Also, the normally used features provided by prior art lighters can be included to satisfy the desires of one skilled in the art.

Claims: 1. A fuel burning lighter comprising: a supply of liquified gaseous fuel (12); burner means (21, 24, 28) communicating with said fuel supply (12); valve means (17, 18) positioned between said fuel supply (12) and said burner means (21, 24, 28) in a housing (25) constituting the only passage for all fuel from said fuel supply (12) to said burner means (21, 24, 28) whereas a clearance (23) is defined to allow said burner means to be movably disposed in said housing; said valve means (17, 18) comprising a valve seat (17) and a valve seal (18) movable between valve open and valve closed positions; a spark producing means, igniting the fuel; means (26, 27) to provide a closing force to retain said valve means (17, 18) in a closed position to prevent gaseous fuel from passing from said fuel supply (12) to said burner means (21, 24, 28); whereas said closing force as a first force is provided by a first elastic means and is opposed by a second lesser force provided by a second elastic means (36, 70) biassing said valve means (17, 18) towards said open position, said first force being capable of being overcome by manually applied counteractive forces enabling said second force (36, 70) to open said valve means (17, 18) as soon as the net remaining closing force is removed or reduced sufficently; characterized in that said second elastic means (36, 70) is positioned in tight engagement between a flange (28) of said burner means (21, 24, 28) and a flange of the housing (25), both flanges extending laterally from said burner means and said housing to prevent entry of foreign matter into said clearance. 2. The fuel burning lighter according to claim 1, characterized in that the amount of said second force is between about 1/5 and 1/2 the amount of said first force. 3. The fuel burning lighter according to claim 2, characterized in that the amount of said second force is between about 1/4 and 1/3 the amount of said first force. 4. The fuel burning lighter according to one of claims 1 to 3, characterized in that said outwardly extending flange (28) is annular and in that said second elastic means (36, 70) is an elastomer ring. 5. The fuel burning lighter according to claim 4, characterized in that said elastomer ring (36, 70) is made of synthetic or natural rubber which is either molded or stamped from a flat strip. 6. The fuel burning lighter according to claim 5, characterized in that said elastomer ring (36) has upper and lower substantially flat surfaces. 7. The fuel burning lighter according to claim 6, characterized in that said circular ring (36) has a cross sectional configuration defined by an inner wall and an outer wall concentric with said inner wall; said inner and outer walls each having a concave configuration to thereby minimize the change of biasing force between valve open and valve closed positions. 8. The fuel burner lighter according to claim 6, characterized in that said second elastic means (36) is maintained in a compressed condition to provide sufficient biasing force for opening said valve means when the resilient means is allowed to expand. 9. The fuel burning lighter according to claim 8, characterized in that when the non-compressed thickness of said second elastic means (36) is compressed between about 0,008 to 0,016 inches (0,2 to 0,41 mm), an opening force of about 3 to 8 ounces (0.85 to 2,27 N) is provided. 10. The fuel burning lighter according to claim 1, characterized in that said valve means (17, 18) includes elastomeric sealing means (18) which is maintained under compression in the valve closed position, such that when said first force is relieved, said elastomeric sealing means (18) assists in moving the valve means (17, 18) to said valve open position. 11. The fuel burning lighter according to one of the preceding claims, characterized in that said valve open position is defined by a stop means (29).

Inventors: SCHAECHTER, FRIEDRICH, SCHÄCHTER, Friedrich
Applicants: SCHAECHTER, FRIEDRICH
Application year: 1988
Main classification: F23Q2
IPC codes: F23Q2