Piezoelectric lighter

Abstract

 A piezoelectric lighter, particularly a gas lighter, including a chassis (1), (2), provided with a pressure trigger (4) and a conductor opening (3), a piezoelectric active element (15) oscillating within the chassis, and two electrodes (5) and (18) connected directly to said piezoelectric active element (15).
One end of the active element (16) is grounded to the chassis and, through the pressure trigger (4), has contact with the metal opening (3) provided with a semicircular-shaped tongue comprising the first electrode.
The other end of the active element (15) has contact with an oscillating metal rod (18) sustained by the insulating support base (13-14) of the same active element (15) able to work as a counter electrode during oscillation and to move facing the first electrode (5).
The active element (15) may be a single ceramic piezoelectric element or two ceramic elements set opposite each other.

Description

[0001] This invention refers to a piezoelectric lighter. More precisely, the present invention refers to a piezoelectric lighter, such as a gas lighter, which has an electric oscillatory circuit forming an integral part of the cartridge, without any flexible parts.

[0002] Piezoelectric lighters with several spark discharges, especially gas lighters, are generally composed of a piezoelectric oscillator inside a chassis and includes a pressure lever. Usually the voltage generated by the variation in pressure is transmitted to two fixed electrodes, placed on the lighter tip, where the sputtered gas or liquid gives rise to the ignition spark, through two separate cables, each having two terminals or solderings.

[0003] The active element, or piezoelectric cartridge, is normally composed of two cylinder-shaped piezoelectric containers, mounted in parallel, with one polarity at the centre and the opposite polarity at the two parallel ends.

[0004] The piezoelectric cartridge with two ceramics has various drawbacks not only due to its rather high cost but also to the fact that the assembly and electric circuit are somewhat complicated. To overcome these difficulties, lighters with several spark discharges have been designed adopting just a single ceramic element.

[0005] Gas lighters having a piezoelectric unit containing just one ceramic are already known.

[0006] Nonetheless, this type of lighter is not entirely satisfactory since it does not manage to simplify the construction to a sufficient degree to be able to reduce the costs. The main handicap lies in the fact that the electric circuit is still kept separate, using flexible cables.

[0007] According to this invention, the above-mentioned drawbacks are eliminated by adopting a piezoelectric lighter in which the piezoelectric cartridge, oscillating inside the container, at one end is grounded to same and, through a pressure trigger, has immediate contact with the metal opening of the chassis provided with a semicircular-shaped tongue constituting the first electrode; whereas, the opposite end makes contact with an oscillating metal rod sustained by an insulating support base of said cartridge able to work as a counter-electrode during oscillation and to slide past the first electrode.

[0008] The cartridge may have a twin ceramic but it is preferable, to simplify the construction and reduce costs, that the cartidge have just one piezoelectric ceramic.

[0009] The most important feature of this invention is that the electric oscillatory circuit forms an integral part of the cartridge, in such a way that the only mobile part of the circuit is the reciprocal counter-position of the two electrodes, between which the spark must strike, whereas the remainder of the electric circuit is articulated but not flexible. Elimination of every flexible element (cables) simplifies assembly automation to a great extent. Another feature of this invention regards the variability of the sparking distance, i.e. it is at its least at starting and quenching of the spark and at its most during the central stage, when ionization occurs thus lengthening the spark.

[0010] This is obtained by curving the counter-electrode, forming an integral part of the opening grounded to the chassis, whose radius is smaller than that of the oscillating arm of the rigid tip in respect of the cartridge. The initial shortness of the distance makes the spark strike quicker and surer and the length of the spark in the central stage increases the efficacy of the lighter.

[0011] For greater clarity, the piezoelectric lighter referred to in this invention will be described heretofore making re-- ference to the enclosed figures showing two embodiments of same, which serve to illustrate but not limit the present invention, wherein :

Figure 1 shows a schematic view of a central cross section of a lighter with a single ceramic cartridge, the electric circuit of which is an inflexible, integral part of same and oscillating with it ;

Figure 2 shows in detail the single ceramic component seen in figure 1 and its assembly on a larger scale ; and figure 3 shows a schematic view of a means of accomplishing a rigid, oscillatory electric circuit if a twin ceramic cartridge is used.

[0012] With reference to figures 1 and 2, the gas lighter referred to in this invention comprises two semipermanent molds 1 and 2 made of molded resin, having coupling holes 6 and 7 and ending in the metal opening at the head 3.

[0013] On the upper surface of the mold 1 juts the trigger 4, indicated as always being compressed and, by the dotted line, in a state cf return and expansion. Inside this layout, which is normally the usual one, is assembled the active element referred to in this invention. Inside the container comprising the two semipermanent molds 1 and 2, is assembled, according to any arrangement, the active active unit 10, mounted on the chassis 11 of the mold 2, grounded, at the end point 12 towards the tip, to the metal opening 3, the tongue extension of which acts as the first electrode of the circuit.

[0014] On this chassis 11, the ceramic cartridge oscillates (in the drawing marked by a single active element), housed in a container 13 made of insulator material. The container 13 forms an integral part of the sheath holding the oscillating rod 14 ; the container 13 and the sheath 14 forming a single molded part.

[0015] In the casing of the container 13 is housed the ceramic element 15, which, through the conductor disk 17, presses against the partition 16. The conductor disk 17 makes contact, by pressure and electric continuity, on the conductor rod 18, inserted in the sheath 14 and constituting the second electrode of the circuit connected at a polarity of the ceramic element 15. On the side of the insulating partition 16 facing the conductor disk 17 is assembled a notched pellet 20, oscillating on the chassis 11.

[0016] On the side of the ceramic element 15 facing that resting on the conductor disk 17, is assembled, by means of the interposition of a shock-absorbing metal washer, a second metal pellet 22 with notch 23, inside which is inserted a corresponding lever expansion 24. The lever 24, in turn, is articulated in 25 on the chassis 11 with which it constitutes a metallic continuity and consequently a conductor element towards the first fixed electrode 5.

[0017] The continuous line in figures 1 and 2 indicates the final position of the trigger 4 and the pressure lever 24, i.e. slightly below dead center and with the rod 18 in the lowered position A.

[0018] Removing the pressure from the trigger 4, the lever 24 takes on the position indicated by the dashed line and the rod 18 moves into position B, also indicated by a dashed line, rotating around point 30. The alpha angle variation of the lever 24 causes a change in the pressure on the ceramic element 15 and generates the pressure which makes the sparks strike between the mobile element from B to A within the beta angle. Within this angle (as better illustrated in figure 2 showing just the active part enlarged and bearing the same numbers as in the previous figure) and along the subtended arc, the distance between 5 and 18 is not constant, it being shorter nearer B to facilitate the spark starting and greater in the intermediate tract to lengthen the sparks in the already ionized air, thus increasing the ignition area of the gas, then to be reduced to the initial value in A, in order to create the same electric and kinematic conditions with an inverted polarity. This is obtained by curving the tongue 5, forming an integral part of the opening 3, the radius of which is smaller than that pivoted in 30 of the ideal arc covered by the head of the electrode 18. In this way one increases the igniting reliability of the spark between 5 and 18 in the position of least distance and one obtains a greater ignition reliability for the gas flowing from the windows 26 and 26', machined on the same opening 3 and aligned with the slit from which the tongue 5 originates and in the one facing it on the other wall.

[0019] From figure 2 it is easy to understand how all the elements may be mutually fitted and engaged merely by slip coupling and pressure. In particular, the notch 30 is slightly larger than the thickness of the chassis 11 to permit an automatic slight misalignment in respect of the second notch 23 on the pellet 22. The pellet 22, in turn, is provided with a bevel 1 23' as compact as possible to be compatible with the coupling of the lever 24 between the two fulcrum points 23 and 25. The container 13, the partitioon 16 and the tubular sheath 14 are molded in a single block out of plastic insulating material able to withstand drilling and stress generated by compression. The tubular sheath 14 blocks the conductor rod 18 with a slight rabbet 17 or with a knurl having a slight undercut.

[0020] In the piezoelectric lighter referred to in this invention the whole electric circuit is accomplished without any flexible elements, the only deformable element being the space of the beta arc wherein the one electrode moves in respect of the other fixed one. In the types of piezoelectric lighters known till now, the electrodes remain fixed and the circuit is flexible through the use of cables. Figures 1 and 2 show a preferred embodiment having a single ceramic element, which, by using known devices, is sufficient to generate sparks strong enough to spark off any gas. However, the aim of this invention also includes the use of a double ceramic element, realized still with a circuit without flexible cables, for example, according to the embodiment shown in figure 3. In this embodiment two ceramic elements ³2 assembled in the container 31, one opposite the other, in such a way as to have one of the two polarities along the same lines as the conductor plate 37 electrically coherent f with the conductor rod 38 contained in the sheath 32. At the two ends of the ceramic elements 32 rest the conductor pellets 39, which, through the lever 24, controlled by the trigger 4, are grounded to the chassis and consequently to the opening as shown in the first solution.

Claims

1. A piezoelectric lighter, especially a gas lighter, com prising a chassis equipped with a pressure lever and at the end having an opening, a piezoelectric element oscillating inside the chassis and two electrodes in correspondence with the tip of the lighter, reached by the gas or liquid to be lit, in electrical contact with same active element, characterized by the fact that one electrode is composed of the conductor opening (3) in electric continuity with the chassis (2) and grounded to a polarity of the active electric element (15), through the pressure lever (24), and the other electrode is composed of a conductor rod (18), which is in electric contact with the other polarity of the active piezoelectric element (15), when under pressure, through a conductor disk (17); said conductor rod (18) being contained in an oscillating insulator sheath (14), forming an integral part of the oscillating container (13) of the active piezoelectric element (15).

2. A lighter, as per claim 1, characterized by the fact that the active piezoelectric element (15) is a single ceramic element, having one polarity directly grounded, through the lever (24) and the chassis (2) to the opening or fixed electrode (3) and a second polarity, through the rod in pressure contact, oscillating until it faces, at a distance lesser than the breakdown voltage, the opening already mentioned. A lighter as per claims 1 and 2, characterized by the fact that the metal opening (3) directly grounded to the chassis, is provided, either by shearing or molding, with a circular-shaped tongue (5) the radius of which is smaller than that of the circle (30) on which the mobile tip oscil- lates (18), consequently the distance is shorter when the electrode is at rest or at end of stroke and greater during the central stage of the excursion.

4. A lighter as per any one of the former claims from 1 to 3; characterized by the fact that the active element (15) is composed of two ceramic elements (32) assembled in parallel, with one pair of polarities grounded to the chassis and to the opening and a second pair aligned in parallel on a conductor plate (37) electrically coherent with the conductor rod (38) oscillating with the active element.

5. A lighter as per any one of the former claims, characterized by the fact that one pellet (20) with notch (30) is set on one side (16) of the insulator container (13), in parallel to the conductor disk (17), and a second metal pellet (22) with notch (23) is set on the opposite side of the active element (15).

6. A lighter as per claim 5, characterized by the fact that the lever (24) is equipped with an extension which is inserted in the notch (23) of the pellet (22).

7. A lighter as per claims 5 and 6, characterized by the fact that the pellet (22) is provided with a bevel (23'). A lighter according to any of the former claims from 5 to 7, characterized by the fact that the notch (30) of the pellet (20) is larger than the thickness of the chassis (11), in order to obtain a slight misalignment in respect of the second notch (23) of the opposite pellet (22).

Drawing