IE45799B1

IE45799B1 - Piezo - electric lighters

Info

Publication number: IE45799B1
Application number: IE2096/77A
Authority: IE
Original assignee: Braun Ag
Priority date: 1976-10-15
Filing date: 1977-10-13
Publication date: 1982-12-01
Also published as: DE2646584A1; GB1550289A; DE2646584C3; AR211742A1; ES463191A1; IE45799L; BR7704464A; DE2646584B2; FR2368148A1

Abstract

High voltage generating device, with percussion mechanics, with a piezoelectric converter percutible by a firing pin, with a compressible energy accumulator spring by an actuator and which on one side leans against the firing pin while on the other side it is supported against the actuator and a retainer for the firing pin, consisting of a magnet and magnetic conductive parts adjacent to the polar surfaces of the magnet, as well as with a recovery spring arranged between the retaining device and the actuator.

Description

This invention relates to a piezo-electric igniter with a piezoelectric transducer subject to the action of a striker with a pressure spring compressible by an actuator, said spring being supported on the one hand on the striker and on the other on the actuator, as well as a holding device for the striker comprising a magnet and magnet conducting pieces resting oa its pole faces and a return spring arranged between the holding device and the actuator.

The piezo-electric igniter according to the invention 10 is particularly suitable for use in gas and cigarette lighters.

Froa German Offenlegungsschrift No. 2,341,523 an igniter is known having a holding device for the striker comprising a magnet and magnet conducting pieces resting oa its pole faces. The holding device is fixed to a locking pin which is centrally supported on the electrical transducer. This central support of the holding device on the electrical transducer significantly impairs the transmission of energy froa the striker to the electrical trans20 dueer and is only obtained if the striker strikes centrally on the electrical transducer. Furthermore, between the electrical transducer and the striker a return spring is provided which returns the striker to its initial position. Baring the actuating process, this return spring acts counter to the tension of the pressure spring and conseqjsoatly cancels out part of the impact energy ef the striker.

The igniter according to Figure 2 of German Offenlegungs- 2 -4-S7Q9 schrift No. 2,341,714 does not have the disadvantages specified hereinbefore because according to this embodiment, the magnetic holding device is fixed to the piezoelectric igniter casing by means of a locking pin which passes through the holding device, the return spring ia located between the holding device and the actuator and the pressure spring which surrounds the striker is located between two stops provided on the striker. However, this construction requires an extremely long striker because its length is dependent on the spring deflection of the pressure spring.

The decisive factors for the total length of such a known igniter are the electrical values such as the ignition energy and ignition voltage which must be achieved, the actuating force and the constructional means such as the size of the electrical transducer, the acceleration travel of the striker and the spring deflections of pressure springs and return springs which must be correspondingly adapted. If the total length of the igniter is reduced whilst retaining the known construction described, this necessarily leads to an increase in the actuating force and/ or a reduction of the electrical values.

The present invention aims to provide a piezo-electric Igniter which does not have the disadvantages of the known , I igniters.

It is a particular aim of the invention to provide a piezo-electric igniter which either permits a reduction in the total length without this reduction causing a drop in the electrical values or a rise in the actuating force - 3 4 S'? 8 © or which ensures higher electrical values and/or a reduction ia th® actuating force whilst maintaining the total length.

A further aia of the invention is to provide a piezo5 electric igniter whose striker acts centrally on the electrical transducer without requiring a locking pin passing through the ma©aetic holding device because the known method of fixing the holding device is susceptible t© wear due to the actuating force which occurs, aad is also very e^ensive to manufacture because the transverse bor® through the holding device for the locking pin can only be produced by ultrasonic drilling methods due to the materials used here.

According to the invention, there is provided a piezo15 electric igniter comprising a piezo-electric transducer, a striker arranged to strike the transducer, an actuator, a first spring located between the actuator and striker and arranged to be compressed on actuation of the actuator, q holding device for the striker comprising a magnet and 2© ascetic conducting pieces resting on the pole faces of the magnet, a second, return, spring arranged between the holding device and the actuator, and a supporting device comprising at least two supports supported on a casing for the transducer and carrying the holding device for the striker, the striker being movable between said supports - 4 4 S '7 S 3 and being provided with a laterally projecting shoulder for engagement by the first spring, said spring coaxially surrounding at least part of the holding device, striker and supporting device and serving to urge the shoulder on the striker against an abutment on the actuator. Preferably, the piezoelectric transducer striker, first spring, holding device and supporting device are mounted within an igniter casing and the actuator, in its inoperative position, projects from said igniter casing.

According to one embodiment of the invention, the return spring provided between the actuator and the holding device acts on the actuator and, via the holding device, on the supporting device and serves to urge the latter against the transducer casing and also serves to urge a shoulder provided on the actuator against a stop on the igniter casing.

In order to achieve a satisfactory support or attachment of the supports on the transducer casing, the ends of the support which engage with the transducer casing are preferably bent. A simple and advantageous attachment of the supporting device on the transducer casing is obtained by the bent ends of the supports being fixed to the transducer casing by means of plates which may form part of the igniter casing.

The central striking of the piezoelectric transducer by the striker can be further Improved by the striker being guided by the supports or by providing the supports with a striker guide. - 5 Advantageously, the supports are made from a nonmagnetic material preferably bronze or chrome nickel steel.

Aecording to a preferred embodiment of the invention, the transducer casing is provided on its end facing the striker with a shoulder whereby said shoulder and the igniter casing forms aa intermediate space in which the shoulder on the actuator moves during the actuating stroke. According to this embodiment, the supports may project into the intermediate space and be fixed to the transducer casing.

It falls within the scope of the inventioa if the igniter casing and transducer casing are made from a single structural member or if the transducer casing is incorporated into the igniter casing. The invention also extends to a cigarette lighter having the above-described piezo-electric igiiter in which the transducer casing, the igniter casing and the casing of the lighter Itself are made from a single structural member.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which?» Figure 1 is a longitudinal section through one embodiment of a piezo-electric igniter according to the invention with a supporting device supported on the transducer casing; Figures 1a to 1d are perspective views respectively of aa actuator, pressure spring, holding device with supporting device and striker of the igniter shown in Figure 1? - 6 45789 Figure 2 is a longitudinal section through a second embodiment of a piezo-electric igniter according to the invention with a transducer casing incorporated into the igniter casing; Figure 3 is a longitudinal section through a third embodiment of a piezo-electric igniter according to the invention in which the igniter casing and transducer casing are made from a single structural member; and Figure 4 is a longitudinal section through a lighter body with integrated igniter and transducer casing.

The piezo-electric igniter shown in Figure 1 comprises an actuator 1, a holding device 2 comprising a magnet and two magnet conducting pieces, a return spring 3, a striker 4, a pressure spring 5, a transducer casing containing a piezo-electric transducer 6, an electrode lead 7 and an igniter casing 8.

The piezo-electric transducer constitutes a separate component. The transducer casing 6 is placed in the igniter casing 8 where it rests on the bottom of the casing.

The holding device 2 is carried by a supporting device which comprises two supports 9, 10 connected rigidly in each case with the two magnet conducting pieces, for example by means of spot welding.

This method of fixing the supports to the magnet conducting pieces is also used for fixing all the parts of the holding device.

The bent ends Sa and 10a of the supports engage with the upper surface of transducer casing 6 where they are - 7 secured under the action of the spring tension of the return spring 3 supported on the one hand on the actuator and on tho other on the holding device. An abutment is necessary to ensure that the supporting device constantly engages on the transducer casing.

This abutment is formed by a shoulder 11 provided on the igniter casing 8 against which engages the actuator 1 provided with a shoulder 12 by aeans of the spring tension of return spring. 3-, which is under an initial tension in the inoperative position of the igniter.

Two abutments 13» 14 with a predetermined axial spacing ore provided in the casing wall of actuator 1. The pressure spring 5 is located between the abutments 13 and 14 and transmits its spring tension to the striker 4 via a shoulder on the striker 4 and, ia the inoperative position of the igniter, presses the shoulder 15 oa the striker 4 against th® abutment 14. Following the ignition process, the abutment 14 serves to return the striker 4 into the inoperative position, i.e. on the two magnet conducting pieces of the holding device 2.

Further details of the piezo-electric igniter are shown sore clearly in the perspective views of Figures 1a to 1d.

As shown in Figure 1a, the actuator 1 comprises a hollow cylindrical casing in whose side wall 17 are provided openings leading to a hollow 'Cylindrical chamber 16 in such a way that from the original casing wall three webs 18, 19, 20 and a plate serving as the abutment 14 are left whilst the stop 13 is formed by the upper edges of the - 8 4 3 7 3 8 openings as seen in Figure 1a. By means of the openings the pressure spring 5 shown in Figure 1b and the striker can be inserted into the actuator between the abutments 13 and 14 whereby the pressure spring can be put under an initial tension. The outer side walls 17 of the actuator are set back somewhat above the openings so that an allround shoulder 12 is formed. At the top, the actuator is covered by a cap 21.

Figure 1c shows a holding device 2 comprising a magnet 22 and two magnet conducting pieces 23, 24 engaging on the two pole faces of the magnet. The magnet conducting pieces 23, 24 each have a shoulder 25 on which is supported the return spring, in that it coaxially surrounds the shouldered part of holding device 2. The supporting device comprising the two supports 9, 10 is fixed to the two magnet conducting pieces for example by means of spot welding at the points indicated by x.

At their ends remote from the holding device, the supports 9, 10 are bent outwardly in the represented embodiment. However, as shown in Figure 1, they can also be bent inwards. Inward or outward bending is dependent on the particular structural conditions on the transducer casing. The supports 9, 10 are made from a non-magnetic material, preferably bronze or chrome nickel steel.

The striker 4 shown in Figure 1d comprises a round pin with a circular shoulder 15 into which two slots are provided to such a depth that part of the cylindrical surface of the pin is also removed. The pin thickness in the - 9 40799 a?ea of the facing slots corresponds to the spacing of the supports 9, 10 of the supporting device relative to one another. The supports 9, 10 also serve as guides for the striker. Thus, the width of the slot is dependent on the width of the .support.

The piezo-electric igniter functions in the following manner. On depressing the actuator 1, the pressure spring 5 engaging on striker shoulder 15 is compressed and stressed until the force of reaction produced in the pressure spring e^KJeeds the magnetic holding force of holding device 2 and the striker is pulled off from the two magnet conducting pieces of the holding device and by releasing the stored energy, speeds in the direction of the piezo-electric transducer.

During the force storage process, the actuator 1 with th® abutment 14 moves up to the piezo-electric transducer. The force of reaction in the pressure spring necessary for the pulling off of the striker is obtained when the abutment 14 is at the same height as an anvil 26 provided on the end face of the piezo-electric transducer 6.

Wen the striker 4 strikes against the anvil 26 of the piezo-electric transducer, a brief pressure is exerted on the piezo-electric element so that a high voltage pulse is generated which is fed to an ignition spark gap via the electrode lead 7. At this time, the pressure spring 5 is virtually relaxed.

Qa releasing the actuator 1, the return spring 3, supported against the holding device 2 and compressed during - 10 a S 7 S 0 the actuating travel, acts between the actuator 1 and the holding device 2 to bring the actuator 1 with its shoulder 12 into engagement with the shoulder 11 on the igniter casing 8. The abutment 14 on the actuate;· thereby drives the striker 4 engaging on the anvil 26 and causes it to engage on the holding device 2 where it is again held by magnetic force.

Figure' 2 shows a piezo-electric igniter comprising a transducer casing 31 inserted in an igniter casing 30. The two ends of the transducer casing 31 are shouldered in a cylindrical manner. A screw-threaded projection 32 projects through an opening provided in the igniter casing 30. A screw cap 33 preferably made from electrically conductive material seals the transducer casing 31 and places ths piezo-electric element located therein under a certain initial tension and fixes the transducer casing to the igniter casing.

The supports 9, 10 of the supporting device engage laterally on the surface of a shoulder 34 on the transducer casing 31 and with their outwardly bent ends engage on the set back casing surface 35 of the transducer casing 31 where they are secured by means of attachment means. The attachment means can comprise, for example as shown, two plate-like projections 36» 37 which are provided in the wall of the igniter casing 30 and which are curved inwardly over the bent ends of the supports and in this way secure said supports to the transducer casing.

Owing to this manner of fixing the supporting device '4 3799 oad holding device 2, the abutment of Figure 1 formed byshoulder 11 on igniter casing 8 and shoulder 12 on actuator 1 becomes superfluous.

The diameter and length of shoulder 34 of the trans5 dues? casing are such that the actuator 1 with its abutment slides over shoulder 34 during its actuation stroke and the latter is coaxially surrounded by the holding device at the time of releasing the striker.

The piezo-electric igniter shown in Figure 3 differs from the piezo-electric igniter shown in Figure 2 only through the combination of the transducer casing and the igniter easing to form a structural unit 40 whose base opening is closed by a screw cap 33 after fitting the transducer components such as the anvil 26 to piezo-electric elements 42, 43 of an electrode plate 44 located between said pieso-electric elements and a further electrode plate 45. Structural unit 40 also contains further components of the piezo-electric igniter such as the holding device with the striker and supporting device together with the actuator and the pressure spring and return spring, as shown in Figure 1 or Figure 2.

The end of the actuating stroke of actuator 1 is shown in exemplified manner by dotted lines in Figure 3.

Figure 4 shows a lighter body 50 which contains a lighter fuel container and in whose wall are integrated parts of the piezo-electric igniter such a3 the igniter casing 8 and transducer casing 6 which receives the electrical transducer. By fitting the transducer components - 12 such as the anvil 2o, two piezo-electric elements 42, 43, an electrode plate 44 located between the piezo-electric elements and a screw 45 and by inserting the previously assembled structural unit comprising actuator 1, the return spring, the holding device with the supporting device, the pressure spring and the striker, the piezo-electric igniter is completed in the lighter body.

Claims

1. CLAIMS;1. A piezo-electric igniter comprising a piezo-electric transducer, a striker arranged to strike the transducer, an actuator, a first spring located between the actuator and striker and arranged to be compressed on actuation of the actuator, a holding device for the striker comprising a aagaet and magnetic conducting pieces resting on the pole faces of the magnet, a second, return, spring arranged between the holding device and the actuator, and a supporting device comprising at least two supports supported on a easing for the transducer and carrying the holding device for the striker, the striker being movable between said supports and being provided with a laterally projecting shoulder for engagement by the first spring, said spring coaxially surrounding at least part of the holding device, striker and supporting device and serving to urge the shoulder on the striker against an abutment on the actuator.

2. A piezo-electric igniter according to claim 1, wherein the piezo-electric transducer, striker, first spring, holding device and supporting device are mounted within an igniter casing and wherein, in its inoperative position, part of the actuator projects from said igniter casing.

3. A piezo-electric igniter according to claim 2, wherein the return spring provided between the actuator and the holding device acts on the actuator and, via the holding device, on the supporting device and serves to urge the latter against the transducer casing, and wherein said return spring also serves to urge a shoulder provided on - 14 ii 3 7 3 9 the actuator against a stop on the igniter casing.

4. A piezo-electric igniter according to claim 3, wherein the end of the transducer casing facing the striker is provided with a shoulder and an intermediate space is formed by the shoulder and igniter casing in which the shoulder on the actuator moves during the actuating stroke.

5. A piezo-electric igniter according to claim 4, wherein the supports of the supporting device project into the intermediate space and are fixed to the transducer casing.

6. A piezo-electric igniter according to any one of claims 2 to 5i wherein the transducer casing is incorporated into the igniter casing.

7. A piezo-electric igniter according to any one of claims 2 to 6, wherein the igniter casing and the transducer casing are made from a single structural member.

8. A piezo-electric igniter according to any one of claims 2 to 7> wherein the ends of the supports engaging on the transducer casing are bent.

9. A piezo-electric igniter according to claim 8, wherein the bent ends of the supports are fixed to the transducer casing by means of plates.

10. A piezo-electric igniter according to claim 9. wherein the plates form part of the igniter casing.

11. A piezo-electric igniter according to any one of claims 8 to 10, wherein the supports are made of bronze or chrome nickel steel. 15 d S 7 9 9

12. Ο A cigarette lighter having a piezo-electric igniter as claimed iii any one of claims 2 to 11, wherein the transducer casing, the igniter casing and the casing of the lighter itself are made from a single structural member,

13. · A piezo-electric igniter according to any one of claims 1 to 11, wherein the striker is guided by the supports,

14. , A piezp-elqctric igniter according to any one of claims 1 to 11, wherein the supports are provided with a guide for the striker.

15. , A piezo-electric igniter according to any one of claims 1 to 10, wherein the supports are made from a non-magnetic material, l6o A piezo-electric igniter substantially as described herein with reference to the drawings.