DE1629891A1 - Piezoelectric ignition device for flammable gases, especially for gas lighters - Google Patents

Description

R. no. υο2β

Ws / tip n.2.1967

Attachment to

Patent and registration:
üobrauohomuotürt ^^ s- ^meiauns

ROB URT BOSCH GMBH, 7 Stuttgart W, Breitscheidstrasse

Piezoelectric igniter for flammable gases, in particular for gas lighters

The invention relates to a piezoelectric igniter for flammable gases, especially for gas lighters, with a piezo element connected to a spark gap and one on the Piezo element acting impact organ, which is via an energy storage device is coupled to an actuator.

00988 5/00 7 4 bath

" ² ' 162989Ί

Robert Bosch GMBH . R. no. 8826

Stuttgart February 13, 1967 Ws / Kp

In known piezoelectric igniters for gas lighters (USA Patent 3 200'295) that is sufficient when one is actuated Often times, the pushbutton generated by a firing pin in the piezo element does not trigger a pressure impulse at the spark gap of the gas to generate sufficiently powerful and sufficiently long ignition sparks. This deficiency cannot be left alone fix it with an increased back pulse as the discharges are on the sagging gap, which is caused both by the pressure increase and by the pressure drop of a pressure pulse can be generated in the piezo element, to follow one another in time. Merely through a relatively large firing pin mass and a matching striker spring sufficiently long and powerful discharges are achieved at the spark gap. The increase in firing pin mass leads however, ignition devices in gas lighters often result in a very heavy construction with relatively large dimensions.

In another known embodiment, the pressure on the piezo element is applied by hand using leverage (Austrian Patent Specification 2410008). The statically acting Forces of 300 - 500 kp also require a heavy, powerful one Construction. An additional uncertainty in such a system is due to the individually different actuation of the ignition device conditional. If the pressure is too low or if the pressure rises, the electrical energy released in the piezo element is Insulation and internal resistances of the circuit derived without generating an ignition spark.

Proceeding from this knowledge, the object of the invention is to be found based on developing an ignition device that, while avoiding the. aforementioned disadvantages from an individually different Actuation is independent, has the simplest and most lightweight construction possible with little space requirement and with de.ren The filling is long enough to ignite the gas

009885/0074

162989Ί

Robert J3oacti GmbH R.-Nr. 8826

Stuttgart 'February 13, 1967 Ws / Ep

powerful discharge occurs at the spark gap.

This is achieved according to the invention in that the impact member consists of a metallic firing pin and a piezo element firmly connected to it, which when the device is actuated hits an anvil accelerated by the energy storage mechanism.

The piezo element is inserted into an insulating sleeve, which is screwed into the firing pin at the front. Piezo element and insulating sleeve are therefore part of the impact organ. This will reduce the weight of the Firing pin greatly reduced, making it simple, light and space-saving Execution made possible in particular with gas lighters.

In the drawing is an embodiment of the subject of the invention " Stand shown. Show it:

Fig. 1 superimposed individual parts of a piezoelectric Ignition device for a gas lighter in a three-dimensional representation,

2 shows the assembled ignition device in longitudinal section,

Fig.? ' the same ignition device in longitudinal section when actuated the pushbutton.

The ignition device shown in Figs. 1-3 has a rectangular shape Housing 10 made of plastic, which contains the individual replaceable igniter parts, such as a push button 11, a return spring 12, an insulating sleeve 13, a piezo element 14, a firing pin 15, a striker spring 16, and a base plate 17 receives.

SAT ORiGIWAL - 4 .-

009885/0074

Robert Bosch GmbH R. No. 8826

Stuttgart ■ February 13, 1967 Ws / Ep

The housing 10 has a hollow cylindrical extension 18 in the upper part, into which a metallic anvil 19 (Flg · 2) is firmly inserted. The anvil 19 has a high-voltage connection 20 which is led to the outside through a recess 21 in the pushbutton 11 and to which a spark gap 22 (FIG. 3) is connected. The piezo element 14 sits in a bore in the insulating sleeve I3, which ^{is screwed into a recess I 1} Ja of the firing pin 15. A striking head 2j> protruding from the end face of the insulating sleeve I3 is arranged on the piezo element. The insulating sleeve 13 is provided with a collar 24 for supporting the impact spring 16, which is supported against the base plate 17 fastened to the lower end face of the housing 10 by means of screws 25.

The piezo element 14, one end face of which over the firing pin 15, the mainspring l6 and the bottom plate I7 is grounded with the other end face over the impact head 23 on its impact on the anvil I9 with this and with the electrode of the spark gap 22 connected thereto, electrically conductively connected, while the other electrode of the spark gap 22 is grounded. The push button 11 is arranged coaxially over the extension 18 of the housing 10 and has a tongue on two opposite sides, which at the lower end with an inwardly directed nose protrude through a slot 18a into the extension 18 and on which the collar 24 of the insulating sleeve 13 rests from below. The return spring 12 is inserted into the push button 11 and is supported against the anvil back 19a in the shoulder 18.

The ignition device is actuated by depressing the pushbutton 11. First, the firing pin 15 is activated by means of the Lugs 27 of the push button 11 pressed down while the mainspring 16 tensioned until the slide strips 28 of the tongues on both sides of the nose 27 via a one attached to the housing 10, obliquely downward sloping plane 29 pushed away and

009885/0074

Robert Bosch GmbH R. No. 8826

Stuttgart 13.2 * 1967 Ws / Ep

the tongues 26 are spread outwards (Fig. 3) This causes the lugs 27 on the collar 24 of the insulating sleeve I3 to disengage and the firing pin 15 shoots upwards, accelerated by the force stored in the striker spring l6 (in Fig. 3 shown in dash-dotted lines). When the impact head 23 hits the anvil I9, the piezo element Ik receives a pressure pulse. The electrical energy released by the rise and fall of pressure in the piezo element 14 is conducted via the anvil 19 to the spark gap 22 connected to the high voltage connection 20, where it causes an ignition spark to ignite the gas. By pressing the push button 11 down, the return spring 12 is also tensioned. It pushes the pushbutton 11 back into its starting position after actuation.

The masses of the anvil and the striking organ are about the same and are about 12g. The firing pin 15 can move around the mass of the piezo element 14 and the insulating sleeve 13 *, i.e. a total of approx. 7 g can be reduced. With this mass ratio it is possible the main discharge and secondary discharge by actuating the ignition device at the spark gap 22 for a time of at least 10 / usec to maintain. Bine additional prolongation of the post-discharge l-: öt itself through an inductive, predominantly ohmic one Reach V / resistance 30, which is connected in series with the spark gap 22 (Fig. 3 shown in dashed lines). Resistance 30 can e.g. be formed by a known interference suppression cable for internal combustion engines.

In a further development of the ignition device according to the invention, the push button 11 is provided with a device for opening a gas valve which must be opened in good time before the spark overflow at the spark gap.

BhZ ORiGiMAt

Claims (2)

Robert 3os eh GmbH 1 R 9 9 8 Q 1 Stuttgart claims 1. Piezoelectric ignition device for flammable gases, in particular for gas lighters, with a piezo element connected to a spark gap and an impact element acting on the piezo element, which is coupled to an actuating element via an energy store, characterized in that 3 the impact element consists of a metallic firing pin (15 ) and a piezo element (I ¹ V) firmly connected to it, which hits an anvil (19) in an accelerated manner when the device is actuated by the energy store (16), 2. Ignition device according to claim 1, characterized in that the piezo element (l4) is inserted into an insulating sleeve (Ij5), which is screwed into a recess (15a) of the firing pin (15). 5. Ignition device according to claim 2, characterized in that on the piezo element (14) over the 'end face of the insulating sleeve (IJ). protruding impact head (23) is arranged. Ignition device according to one of claims 1-3 »characterized in that that the one end face of the piezo element (14) over the firing pin (15) »the impact spring (16) and the base plate · (17) is on the ground and the other end face when it hits the anvil (19) over the impact head (2J) with the one on the anvil "(19) connected spark gap (22) electrically connected 009885/0074 * ° <** Robert Bosch GmbH 'R.-Nr. 8826 Stuttgart ¥ February 13, 1967 Ws / Ep 5. Ignition device according to one of claims 1-4, characterized in that that its actuator is designed as a push button (11) is, which coaxially over the in the upper approach (Ib) of the Housing (10) attached Ambo3 (I9) is arranged and the two opposite sides a tongue (26), which at its lower end with an inwardly directed nose (27) protrude through a slot (18a) into the extension (18) and on which a collar (24) of the insulating sleeve (13) rests from below. H. Ignition device according to Claim 5 *, characterized in that the tongues (26) on both sides of the lugs (27) have a slide bar (28) which, when the pushbutton (11) is pressed down, each over a sloping downward track (29) on the housing (10) push away and at the same time spread the tongues (26) outwards to release the percussion organ » 7. Ignition device according to one of claims 1-6, characterized in that daiä in the push button 11, a return spring (12) is used, which is in the housing extension (18) against the Anvil back (19a) is supported. BAD-ORKSIMAt 009385/0074 L e β r s e 11 β