Abstract: The invention relates to a method for producing a longlife, resistant spark plug for internal combustion engines. The electrode (16), according to the invention, of the spark plug is assembled from a plurality of initial parts: an initial part for a corrosion-resistant shell (31'), an initial part for a core (33') of high thermal conductivity, and an initial part for an erosion-resistant region (32'). These initial parts are jointly impact-extruded to form an electrode blank which is formed into the center electrode (16) by machining its head (51) and its region on the combustion-chamber side. Electrodes which are especially highly stressed are given a fourth initial part, which is also to be impact-extruded, consists of highly erosion-resistant material and is still arranged on the combustion-chamber side in front of the erosion-resistant region (32'). The electrode (16) can be used as a center electrode (16), but can also be used, if necessary, as an earth electrode after an embossing and bending process.

Abstract: An electric potentiometer is proposed, which serves to convert a displacement movement into an electrical signal. The electric potentiometer has a wiper lever with brush wipers which upon a rotational movement about a pivot shaft stroke electrically conductive layers applied to a carrier plate. An electrically nonconductive layer is applied on the resistor layer such that in the region of the electrically conductive layer that is strokable by the wiper upon its deflection, a pickup zone which is narrower than the wiper and is defined on both sides by the electrically nonconductive layer remains uncovered by the electrically nonconductive layer.

Abstract: A nozzle holder for internal combustion engines is proposed, in which a sleeve can be secured in the cylinder head by means of a tightening nut. The sleeve protects the portion of the nozzle which protrudes into the combustion chamber from thermal effects. Ease of serviceability is attained in that when the nozzle holder is rotated out of the cylinder head, the sleeve is simultaneously removed, without requiring additional hand operations.