Contact-Breaking Ignition Plug and Method of Generating a Spark Therewith

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein throughout the various figures of the drawings there have been generally used the same reference characters to denote the same or analogous components and wherein:

FIG. 1 shows a front view of an exemplary embodiment of a break or contact-breaking ignition plug;

FIG. 2 shows a longitudinal sectional view of the break or contact-breaking ignition plug depicted in with FIG. 1 taken along the line II--II of FIG. 3;

FIG. 3 shows an end view on the electrode side of the break or contact breaking plug in accordance with FIG. 1 viewed in the direction of the line III--III thereof; and

FIG. 4 illustrates in longitudinal sectional view a further embodiment of break or contact-breaking ignition plug constructed in accordance with the present invention.

Describing now the drawings, it is to be understood that to simplify the showing thereof, only enough of the structure of the break ignition plug or contact-breaking ignition plug has been illustrated therein as is needed to enable one skilled in the art to readily understand the underlying principles and concepts of the present invention. Turning now specifically to FIG. 2 of the drawings, the break or contact-breaking ignition plug illustrated therein by way of example and not limitation will be seen to comprise a substantially cylindrical contact-breaking ignition plug housing 1 with a polygonal profile 3, for instance a hexagonal body portion, made of a suitable metallic material which, however, is non-magnetic. The housing 1 narrows or is shouldered down towards a threaded portion 2 for screwing into and establishing electrical ground contact with a here not particularly shown electrically conductive machine member, such as a cylinder head of an internal combustion engine or an ignition or detonator system. The threaded portion 2 terminates in a nose or boss or projection 27 arranged at one side for fastening a fixed or stationary contact electrode 25.

The outer surface of the housing 1 possesses vent openings or passages 7 and 7' which lead into a hollow space or cavity 4 and an annular clearance space 8. The housing 1 is provided at an end opposite to the threaded portion 2 with a thread 11 for a cap 22 having a thread 11'. In the cap 22 there is arranged a bore or hole 32 for an ignition cable 29 as well as a conductor disc 14 for an electrical connection 13 an provided with seals 31 and 12.

A magnet coil 5 constituting an electromagnet is provided with insulating plates 30 and is inserted into the hollow space or cavity 4 of the housing 1, leaving free the annular clearance space 8. Furthermore, there is inserted into the hollow space or cavity 4 and within the magnet coil 5 a magnet core 6 which is made of magnetic material and possesses in the region of an armature 18 an approximately mushroom shaped region or enlargement 9 of increased wall thickness. The mushroom shaped region 9 has a conically extending tip 10. The magnet core 6 is supported on an insulating seal 23 at the tip 10. The magnet core 6 possesses a central bore or cavity 15 of a stepped configuration containing enlargements or hollow spaces 15' and 16 formed by shoulders.

The armature 18 is made of magnetic material and extends beyond the magnet core 6 in the region of the hollow space or cavity 16 in the magnet core 6. The armature 18 possesses a blind bore 17, by means of which it is fastened to a free end 19A of a support rod 19 of electrically conductive, elastically resilient material. At its head portion or end 20, the elastic or resilient support rod 19 possesses an electrical connection and is anchored or fixed in the magnet core 6 at a head end or portion 6A thereof. The armature 18 is situated asymmetrically in relation to the longitudinal center plane of the cavity 16 and to a contiguous recess or pocket 28 of the threaded portion 2. The armature 18 is provided with a recess or step 26 in the region of the combustion chamber or the like. A movable or mobile contact or first electrode 24 is arranged in the armature 18 at a free end 18A thereof in the region of this step 26. The armature 18, the mobile contact electrode 24 and the stationary contact or second electrode 25 are arranged such that they are easily replaceable or exchangeable. The heads of the mobile and stationary contact electrodes 24 and 25 are arranged in mutual confrontation and are in mutual electrical contact in the rest or idle position of the mobile contact electrode 24.

FIG. 4 illustrates a further embodiment of break or contact-breaking ignition plug. This break or contact-breaking ignition plug as illustrated in FIG. 4 contains an essentially cylindrical housing 1 which is composed of a lower portion 1' equipped with air vents or openings 7 located at a region which tapers or converges towards the thread-in or threaded side of the contact-breaking ignition plug, a threaded portion 2' and a protruding nose or projection 27 provided with an electrode 25 as well as an upper portion or section 1" having the air vents or openings 7' in a flattened part or portion thereof. At the upper free part or portion there is provided a multi-edge or polygon profile 33 having an internal thread or threading 34 for a screw or threaded bolt 35 possessing threads. This screw or threaded bolt 35 is provided at its central region with a recess or bore 35' for receiving an electrical connection 13. This electrical connection 13 is pressed by the screw or threaded bolt 35 against a disc or plate 14' formed of electrically conductive material. This conductive disc or plate 14' is arranged in the hollow space or cavity 4 of the housing 1. This conductive disc or plate 14' is provided with the seal or insulation 12' bearing upon the insulation structure or insulation plate means 30' or the magnet coil 5 surrounding the magnet core 6. The magnet core 6 possesses, as viewed in the direction of the armature, an approximately mushroom-shaped enlargement or reinforcement element 9' possessing a conically extending tip 10, a central hollow bore or space or cavity 15 with a step-shaped or stepped enlargement or widened portion 15' and a sealing ring or electrical insulation means 23'. The threaded portion 2' constitutes support means for supporting the sealing ring or electrical insulation means 23' and establishes electrical ground contact for the electrically conductive machine member which is equipped with the break or contact-breaking ignition plug. Below the sealing ring 23' there is provided a stepped or widened portion 16 defining a hollow space in the threaded portion 2'. In the hollow bore or space or cavity 15 and widened portion 15' there is arranged an elastic or resilient support rod 19 which protrudes past the magnetic core 6. The second or lower or free end 19A of the elastic or resilient support rod 19 carries the armature or armature piece 18 protruding beyond the magnet core 6 and asymmetrically secured to a second or free end 19A of the support rod 19 and in relation to the longitudinal central plane of the hollow space or cavity 16 externally of the magnet core 6. The elastic or resilient support rod 19 is pressed-into or welded or otherwise appropriately attached with its first end 20' to the upper part or head end 6A of the magnetic core 6. The arrangement is such that the magnet core 6 defines the longitudinal axis of the break ignition plug and the support rod 19 extends substantially along said longitudinal axis in the cavity 15.

The electrodes 24 and 25 which are readily exchangeable and which are respectively arranged at the armature 18 at a free end 18A thereof and at the nose or projection 27, are in contact with one another at their head portions in the rest position. The electrode or stationary contact electrode 25, which is carried by the support means or threaded portion 2', possesses a beveled or tapered portion, whereas the electrode 24 is constructed to be domed or arched. A copper wire which is covered with ceramic insulation or is eloxidized, i.e. electrolytically oxidized, is provided as the winding of the magnetic coil 5, and one end or first electrical conductor means 13' thereof is connected with the conductive disc or plate 14' on the input side and the other end or second electrical conductor means 13" is connected with the magnetic core 6 on the output side. The housing lower portion 1' and the housing upper portion 1 " are covered by mutually interengaging recesses or the like equipped with a securing ring 36. It is possible to dispense with the use of the insulation between the magnetic core 6 and the winding of the magnetic coil 5 if there are employed ceramic-coated or a specially eloxidized, i.e. electrolytically oxidized copper wire for the coil winding.

The mode of operation of the break or contact-breaking ignition plug is as follows:

The electrical potential of a conventional battery or other suitable power source is either transformed to a higher value or is directly supplied. Depending on the number of cylinders or apparatuses to be driven, the battery or power source is connected to an appropriate number of thyristors which, in turn, are also connected to an appropriate number of break or contact-breaking ignition plugs. A distributor or a timer with an ignition pulse generator controls the thyristors such that, depending on the desired ignition sequence, they supply control or electrical ignition pulses to the appropriate cylinders or apparatuses. The ignition current energizes the electromagnet and also flows through the electrical circuit or short-circuit path formed by the contact electrodes 24 and 25. The magnetic field which builds up generates a magnetic effect in the region of the armature 18. The shape of the mushroom shaped region 9 of the magnet core 6 ensures a concentration of this magnetic effect. Besides the magnetic pull effect or attraction on the armature 18 there is also caused a separation or repulsion effect between the magnetic core 6 and the armature 18 due to the pattern of the magnetic field lines or the lines of magnetic flux. These magnetic effects conjointly induce a motion of the armature or armature piece 18 and with it the mobile contact electrode 24 from an idle position in which the electrical circuit or short-circuit path is closed into a magnetically deflected position in which the circuit is interrupted and which is limited by the seal 23 or 23' as the case may be. When the contact electrodes 24 and 25 are separated, an ignition spark is formed and this separation also causes an interruption of the electrical circuit or short-circuit path so that the magnetic field collapses again and the contact electrodes are able to return to the contact or closed position, i.e. the idle position.

The invention is not limited to the illustrated exemplary embodiments. Since it is possible to employ break ignition plugs or contact-breaking ignition plugs for motors other than piston engines and also for other purposes, the housing of the ignition plug can have a form other than cylindrical or, as explained, can be assembled from individual components. In such case and with corresponding construction, the inner components would have to be adapted to the selected form. The contact electrodes can also be mounted differently or arranged differently. The cavities and clearance spaces can be partially or completely filled with insulating members and the vent openings renounced.

While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. ACCORDINGLY,