US3425783A - Electric gas lighter having a piezoelectric stack - Google Patents

Description

Feb. 4, 1969 KNJIRO GoTo 3,425,783

ELECTRIC GAS LIGHTER HAVING A PIEZOELECTRIC STACK Filed Nov. 8. 1966 Sheet of 5 INVENTOR. KENII RO GOTO 3,425,783 ELECTRIC GAS LIGHTER HAVING A PIEZOELEGTRIC STACK Filed Nov. 8, 1966 KENJIRO GOTO Feb. 4, 1969 Sheet Kx-:NJIRQ GOTO F eb. .4, 1969 ELECTRIC GAS LIGHTER HAVING A PIEZOELECTRIC STACK Filed Nov. 8, 1966 NAW.

United States Patent Oce 3,425,783 Patented Feb. 4, 1969 3,425,783 ELECTRIC GAS LIGHTER HAVING A PIEZO- ELECTRIC STACK Kenjiro Goto, Tokyo, Japan, assignor to Mansei Kogyo Kabushiki Kaisha, Kamiaokicho, Kawaguchi shi, Sauama-ken, Japan Filed Nov. 8, 1966, Ser. No. 592,780 Claims priority, application Japan, Nov. 11, 1965, 40/91,596; Mar. 12, 1966, 41/1S,094, 41/15,095, t1/22,027; May 26, 1966, 41/ 49,270 U.S. Cl. 431-255 4 Claims Int. Cl. F23g 2/16, 2/28, 7/18 ABSTRACT OF THE DISCLOSURE An electric gas lighter having a piezoelectric stack and a pair of discharge electrode electrically connected to the poles of said stack. A movable hammer spring-biased to the stack, yan actuator including a spring loaded cam plate for moving the hammer away from the stack and releasing it for rapid movement towards the stack and a pressure bar for constantly applying an adjustable, permanent press-ure to the stack.

This invention relates to improvements in land relating to liquefied -gas fueled cigarette lighters provided with piezoelectric spark ignition system.

It has been already known to equip the liquefied gas fueled cigarette lighter, referred throughout this specication briey as gas lighter with piezoelectric crystal element for generating a high voltage ignition current `by the application of a sudden and abrupt pressure onto the element, so as to generate ignition sparks between a pair of spark electrodes mounted in close proximity of the gas outlet opening of a conventional burner nozzle of the lighter.

According to my practical experiments, a shorter durable life of the piezoelectric element has been encountered on account of liable fand frequent breakage of -the element in the course of frequently repeated igniting manipulations of the gas lighter of the kind above referred to. Upon investigation, it was now found that this kind of breakage is attributable to eccentric pressurization of the piezoelectric crystal which leads in la gradual separation of the conventional blow-receiving metallic head xedly attached, for instance, by the application of sticking agent, to the piezoelectric crystal, from the latter.

The main object of the present invention is therefore to provide a gas lighter, capable of minimizing the possibility of breakage of piezoelectric element during its usage to a minimum, so as to elongate its usable life and at the same time to assure a reliable and positive ignition of the gasiiied fuel at each application of a forced blow against the head f the piezoelectric element by a hammer arranged to cooperate therewith.

With use of the conventional gas lighter of the above kind, other drawback is encountered to avoid overheating of the spark gap electrodes by the issuing gas llame, because these electrodes are positioned in close proximity of the outlet end of the burner nozzle. According to a prior proposal, these electrodes are receded from their working position after the generation of iginiting sparks for the purpose of avoiding overheating of the electrodes. Such a counter measure as this will invite a highly complicated mechanism for advancing land receding the electrodes upon each manipulation of the gas lighter for desired ignition.

A further object of the present invention is to provide an improved gas lighter, capable of avoiding any overheating of the spark electrodes even when the burning of the fuel gas should extend for a long period of time, for instance, ten minutes or so.

Another object of the invention is to provide a gas lighter which is highly compact in its design, economical in its manufacture and eicient in its working efliciency.

The foregoing and other objects, features and advantages of the invention will become apparent from the following more particular description of substantially a preferred embodiment of the invention, as illustrated in the accompanying drawings only for the illustrative purpose and thus in no limiting sense of the invention.

In the drawings:

FIG. l is a longitudinal section of a preferred gas lighter embodying the novel teaching of the present invention, illustrating the non-operative conditions thereof.

FIG. 2 is a similar sectional view, yet somewhat simplified for the illustration of part of the outline configuration of the gas lighter, illustrating the working mode thereof.

FIG. 3 is a perspective view of several main working parts of the foregoing embodiment, wherein however a pusher type manipulating member is depressed to its intermediate position.

FIG. 4 is a similar view to has been depressed fully to its lowermost position.

FIG. 5 is a front view of several preferred working parts when seen from right to left in FIG. 4, wherein however substantially half of the figure is shown in its longitudinal section for the purpose of. showing specilically inside hidden working parts.

FIG. 6 is an inverted plan view of the assembly shown in FIG. 4, wherein however the fuel container tted therein has Ibeen omitted from the drawing for simplicity thereof.

FIG. 7 is a longitudinal section of a modified burner nozzle assembly wherein an ignition circuit is addition'ally and schematically illustrated.

Now referring to the accompanying drawings, especially FIG. 1 thereof, 10 denotes a substantially cylindrical casing of a liquefied gas fueled cigarette lighter, `said casing being semiopened at 10a at its upper end and fully opened at its lower end at 10b, yet additionally closed by means of a bottom cover 17 which is positively kept in position at least a dowel pin 18 and a slidable pin 100. This pin is slidably mounted in a blind hole 101 cut horizontally in the cover 17 and urged resiliently by a compression spring 102 which is inserted in the hole. Pin 100 is formed with a reduced end 100a which is snugly received in an opening 103 boned through the casing wall in close proximity of its lowermost end 10b. The casing Wall is formed with a plurality of 'air inlet openings 10c for the communication of the substantially closed upper space above a liqueed gas fuel container 12 which is positioned tixedly in the lower left corner of the interior space of the casing 10 as most clearly seen in FIG. 1, with the ambient atmosphere for supplying the combustion air, `as will be more fully described hereinafter.

The closing upper casing wall 10d is formed with a iiame outlet opening 10e kept in vertical alignment with flame guide mouth piece 19 which is made of a heat resistance material such as ceramic for instance steatite and iixedly mounted on a ange piece 104 iixedly attached to the upper end portion of a conventional fuel gas nozzle 20. This nozzle 20 is slidably mounted with its lower end in the interior of a conventional nozzle valve 11. With the nozzle 20 positioned as shown, the valve 11 is positively closed so that any gasified fuel can not be delivered from the interior of fuel container 12 through the valve 11, nozzle 20 and `mouth piece 19. On the contrary, when the nozzle 20 together with mouth piece 19 and ilange piece 104 is elevated intentionally as will be more fully described hereinafter, -the liquid fuel at 105 contained in the fuel container 12 is led as conventionally into the nozzle FIG. 3, wherein the pusher valve 11 and gasified therein, thence delivered from the mouth piece 19 through the intermediary of the burner nozzle 20. There is provided a fuel charge valve 21 through the bottom of the fuel container 12, so as to give a facility of charging the liquefied fuel as conventionally.

Numeral 13 denotes a piezoelectric element, preferably formed into a rigid circular cylinder made of, such as, for instance, balium titanate, lead zirkonate or the like ceramic material and polarized as conventionally, which element is rigidly fitted at its lower end with a rigid metallic head 23 through the intermediary of an aluminum sheet 24 tightly stuck on after another, for instance, by means of a convenient sticking agent.

Head 23 is formed on the lowermost or shock-receiving surface with a recess 23a which receives snugly the upper end of an elongated pressure bar 31, the lower end part of which is formed with screw threads 31a kept in engagement with an adjusting nut 32. By manipulating this nut 32, the pressure bar 31 can be shifted along its longitudinal axis so as to modify the initial pressure acting against the piezoelectric element 13 by the pressure bar 31 through the intermediate of the head 23.

14 represents a hollow hammer piece which is rigidly fitted with a sleeve slide 106 kept in sliding fit with the pressure bar 31 acting at the same time as a guide bar to the ham-merslide assembly. When necessary, the slide can be dispensed with so as to form the ham-mer proper as the slide. Around the bar 31, there is provided a pressure spring 29 which is tensioned between the hammer piece 14 and the adjusting nut 32.

At the upper en-d or positive pole of the piezoelectric element 13, there is provided a conductor plate 25 which is made of copper, bronze or the like conducting material and conductingly and tightly attached to the element and backed up by an insulator block 26, preferably made of alumina, steatite or the like insulating material having a high mechanical strength.

A protecting cover sleeve 27 made of insulating synthetic resin such as tetrafluoroethylene, poly styrol, phenol resin or the like, is enclosing the piezoelectric assembly comprising head 23, piezoelectric element 13, conductor plate 25- and insulator block 26 upon application of liquid insulating agent such as silicon wax or the like, so as to unite the assembled constituent physically into a mechanical unit. The cover sleeve 27 is tformed with a side opening 27a within which the free end of the conductor plate 25 projects.

A wire conductor 109 is fused at its one end with lthe projecting end of the plate 25, while the opposite end of the conductor 109 is connected through a spark-stabilizing and retarding resistor 108 to a positive spark electrode 110, said conductor 109, resistor 108 and the root portion of spark electrode 110 being enclosed and maintained in position by a protecting bend tube 107 made preferably of an insulating synthetic resin material and extending from the aforementioned opening 27a in an outward and upward direction as shown. The protecting tube 107 is enclosed at its upper portion by a semi-closed ceramic insulator 113 and the electrode 110 passes the wall of the latter and protrudes a slight distance therefrom so as to form the positive electrode proper kept in substantially opposition to a cooperating or negative electrode 111 for establishing a permanent spark gap. The latter electrode 111 is rigidly supported on a horizontally projecting support arm 114 which is made of a rigid and conductive metal such as steel and protrude from a metallic mount 22 extending vertically yfrom the tank top wall of the fuel container 12. Said mount 22 serves vfor positively supporting the insulator 113 which is formed with suitable projection means 113 kept in engagement with substantially corresponding reception opening means 22a formed in the mount 22, as will be most clearly seen Vfrom FIG. 2.

28 denotes a rigid back-up mount made of iron, zinc or other suitable metal or alloy, having an elongated channel in its cross-sectional configuration and being in pressure f engagement with the upper extremities of both of insulator 26 and cover sleeve 27. In a modification, the insulator 25 can be replaced -by a second piezoelectric element arranged physically in series with, yet electrically in parallel to the first piezoelectric element 13, so as to form a piezoelectric stack. In FIGS. l and 5, this modified arrangement has been illustrated in place of the basic embodiment so far described.

29 denotes an actuating spring for the hammer 14, the upper end of the spring abutting against a shoulder 14a. forme-d on the hammer and the lower end of said spring being kept in pressure engagement lwith a spring mount which is made integral with adjusting nut 32 which abuts against a bottom wall 11651. of mounting frame 116 through the intermediary of stopper 117, said frame 116 representing substantially an elongated rectangular shape when seen from left or right in FIG. l or 2, as may be well supposed from the observation of FIGS. 3-6, especially FIG. 5.

The upper end of the mounting frame 11-6 represents an overlapped double wall construction comprising top wall parts 116b and 116C kept in pressure engagement with the recessed upper surface of the back-up mount 28. The said frame 116 is mounted lwith its lowermost end at 116cz in a recess 119 formed on the bottom cover, while the upper end of the fra-me is kept in position by engagement with the lowermost edge at 101t of the bent-down part of the top wall 10d of lighter casing 10i. The lower threaded end of bar 31 is kept in meshing relation with a rfemalethreaded opening 118 boxed through the lowermost lateral wall 116a.

Manipulating pusher 16 comprises a button head 120 and a stem 121, the latter having a channel-shaped crosssection when cut in a horizontal plane and being formed from a unitary sheet by pressing. The pusher 16 is mounted with its stem 121 in an overlapped and slidable relation with the mounting frame 116 which construction will be most clearly seen from FIGS. 3-4. The stem 121 is formed with a projection 121a to which one end of a return spring 122 is attached, while the opposite end of the latter is supported by the upper part of an elongated dish 123 kept in position on the bottom cover 17 and within the right lower corner of the interior space of casing 10, when seen in FIG. 1 or 2, thus the pusher 16 being always subjected to an upwardly directing resilient force.

A stepped pin 36 is fixedly mounted by the lower part of stem 121 and a hook 37 is rotatably mounted on the said pin 36 and urged resiliently to rotate in the counterclockwise direction when in FIGS 3 and 4, under the infiuence of an urging spring 124.

Motion-receiving pin 33 is fixedly attached to the hammer piece 14 and mounts rotatably a sleeve 34 which is normally kept in engagement with the hook 37. For preventing unintentional stipping-out of the sleeve 34 from the pin 33, thereis provided a spring clip 35 which is received a circular groove 33a formed on the pin.

Operating lever 43 adapted for elevating the burner nozzle 20 in its position from that shown in FIG. 1 to that illustrated in FIG. 2 is pivotable about a pivot pin 44 mounted by side mount 22, the motion-receiving end 43a of said lever being separated from the cooperating projection a depending from the button head 120, when the gas lighter is kept in its non-operating position, as will be notedfrom corresponding dotted line representation shown in FIG. 1, while in the operating position these mating pa-rts :43a and 120a are brought into engagement with each other, as shown in FIGS 3 and 4.

The operation of the gas lighter so far described is as follows:

When it is desired to initiate the ignition of the gasied fuel, finger pressure is exerted upon the button head 120 of manipulatable pusher 16 against the action provided by pusher-returning spring 122, which pusher thereby accompanies the hook 37. Downward motion is therefore transmitted to the hammer piece through the hook 37 and follower pin 33 kept in engagement with each other, while the actuating spring 29 is compressed. In the course of this downward movement, the hammer piece is positively guided along the guide bar 31 always in a concentric relation with the longitudinal axis of the piezoelectric assembly comprising head 23, piezoelectric element 13, insulator 26 (which may be equally a piezoelectric element as was referred to hereinbefore) and back-up piece 28. When the hammer piece has m-oved to a predetermined point through an intermediate stage shown in FIG. 3, the pin 33 with its rotatable sleeve 34 will slip out from the engageable recess formed on the hook 37, thus the hammer piece 14 being released perfectly Afrom the engagement with the manipulating pusher and subjected to the urging force provided by the now strongly compressed actuating spring 29. Therefore, the hammer piece will strike rushingly against the motion-receiving lower surface of the head 23, in a precisely concentric manner, thereby giving an evenly `distributed pressure upon the head, and therefore, to the piezoelectric element 13, or stack 13 and 26.

By preliminarily adjusting the nut 32, the -bar 31 can be kept in a slightly pressurized relation with the piezoelectric assembly and therefore the head is kept always in pressure contact with the element 13, which assures to prevent any unintentional physical separation of the head from the element, even though the head is subjected to frequent and severe blows provided by the hammer piece. In this respect, the aforementioned concentric guidance of the hammer relative to the piezoelectric assembly Will contribute to prevent the aforementioned unintentional separation which will invite possible breakage of the piezoelectric element or elements.

Slightly before the aforementioned striking action by the hammer piece being brought into effect, the operating projection 120a of the button head is brought into engagement with th'e lmotion-receiving end 43a of the operating lever, which thereupon is caused to rotate in the clockwise direction when seen in FIGS. 3-4, so as to elevate the nozzle burner assembly 19-104-20 in its position against a returning spring, not shown, which is contained in the nozzle valve 11, which is thus opened in the conventional way. Therefore, the liquid fuel contained in the container 12 will be evaporated in the valve and delivered therefrom through the nozzle 20 and mouth piece 19 in the form of a gas jet. After initiation of this gas jet flow to take place, say upon elapse of several microseconds from that initiation, the aforementioned striking action will be brought into effect.

rl`he thus generated high pressure voltage, say, 7,000- 10,000 volts, will be conveyed through conductor plate 25 from the piezoelectric element 13 or elements 13 and 20, as the case -may be, thence through wire conductor 109 and resistor 108 to the positive side spark electrode 110. On the other hand, the negative potential is conveyed from the piezoelectric asssembly through the casing and support arm 112 to the negative side spark electrode 111, thus heavy sparks -being generated through the spark gap defined by the both electrodes and serving to ignite the discharging gas jet stream, so as to produce a burning flame which will emerge from the flame guide opening 10e. Combustion air will be supplied from the ambient atmosphere through air inlet openings 10c` assisted by the forced ventilation caused by the outgoing burning gas jet.

When the finger pressure exerted upon the pusher head is released, the moved parts occupying other position than that shown in FIG. l will be brought back to their initial one under the influence by the return spring 34 and nozzle-return spring contained in the burner nozzle 11.

When it is desired to adjust the preliminary compressive force exerted by the bar 31 upon the metallic head 23, the stopper 117 is flattened into a plane sheet by pulling the upwardly projecting end of the stopper by exerting a manual force. Then, the adjusting nut 32 can be turned in one or the other direction so as to tighten or loosen, as the case may be, for exerting any initial precompression axial force upon the head 23. When the adjustment has been completed in this way, the flattened stopper end is again shaped into an angular projection so as to engage in one of the peripheral recesses formed on the nut. In the course of said adjustment, the actuating spring 29 serves for checking the upward movement of the nut, and thus the bar 31 can be advanced upwardly to increase its exerting pressure upon the head 23, when the nut is turned in the so desired direction.

In the modified nozzle arrangement, the nozzle mouth piece 200 is formed with a gas expansion chamber 201 which is fiuidly connected with the ow passage of a nozzle similar to that shown by 20 in the foregoing embodiment.

Mouth piece 200 is formed with a main gas passage opening 202 and an auxiliary gas passage opening 203, said both openings being kept in fluid communication with the expansion chamber. In close proximity of the aux. opening 203, there is provided a pair of spark electrodes, which are only designated jand signs and may be constructed in the similar manner as those designated by and 111 in the foregoing embodiment, although their specific configuration and mounting means have been omitted for simplicity.

When the gasified fuel is supplied from the nozzle proper by opening the burner valve which may be similar to that shown in FIG. l by 11 and in the aforementioned manner, the gas will flow through the both passage openings 202 and 203. When sparks will develop in the aforementioned manner, the aux. and weaker gas jet issuing from the smaller opening 203 is firstly ignited. The thus burned aux. gas jet will ignite the main gas jet issuing from the main passage opening 202, the flow energy of which is thereby augmented and thus the aux. or pilot flame will be correspondingly weakened, so that disadvantageous heating effect provided by the burning flame upon the relatively sensible -park electrodes can be substantially avoided. In this way, an efiicient and durable sparking performance of the electrodes and thus the advantageous ignition performance of the burner assembly can be assured even when the gas lighter is utilized in a highly repeated and' frequent manner.

While the invention has been particularly shown and described with reference to substantially a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

I claim:

1. A gas lighter comprising:

(A) a lighter casting;

(B) a liquefied gas fuel reservoir within said casing;

(C) a burner nozzle in fluid communication with said reservoir and having an outlet end for selective delivery of a gasified fuel stream;

(D) a piezoelectric stack having a metal head fixed thereto and electric poles;

(E) a pair of discharge electrodes mounted in said casing in close proximity of said nozzle outlet;

(F) a spring loaded hammer slidably mounted within said casing for movement toward and away from said metal head and carrying a pin extending in a direction perpendicular to the direction of hammer movement;

(G) current conducting means electrically connecting said poles to said electrodes;

(H) a pusher mechanism slidably mounted on said casing; and

(I) a spring loaded cam pl-ate-rotatably mounted on said pusher mechanism and adapted to engage said pin upon travel of said pusher mechanism in a direction withdrawing said hammer from said metal head and to release said pin upon traveling over a predetermined distance in that direction whereby said hammer is released to collide with said metal head. 2. A gas lighter as dene-d in claim 1 further comprising a pressure r-od having a threaded part and passing through a longitudinal bore in said hammer into contact with said metal head; a compression spring wound about said pressure rod and positioned between said hammer and said casing to bias said hammer in a direction toward said metal head; and a nut on said threaded part for adjusting the pressure effort exerted by said pressure rod onto said metal head.

3. A gas lighter as defined in claim 1 further comprising an insulator mount fixed on said reservoir and carrying one of said electrodes; a receiving recess formed on saidv mount and carrying the other of said electrodes; and -a resistor carried on said receiving recess.y

4. A gas lighter as delined in claim 2 further comprising a hollow sleeve made of synthetic resin material having a high lubricating characteristic and mounted in said longi-k tudinal bore formed through said hammer for guiding saidV pressure rod with a light sliding resistance than otherwise.

References Cited UNITED STATES PATENTS v3,200,295 8/1965 owens61a1.f 31o- 83X 3,220,459 11/1965 wilson 31o- 8.7X

k3,271,624 y 9/1966 Kingmaetal 317-81 3,298,421 1/1967 Tezuka e1a1 431-255V 2/1967 Furth 31o-8 Harkness 123-148-

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