Abstract: In a spark plug in which a space between a center electrode at the top end side and a terminal electrode at a rear end side which are arranged to be opposite to each other in an axial hole of an insulator, the glass seal is effected at a temperature within the range of 500 to 1000.degree. C. and under a condition where the concentration of oxygen is 12 vol % or less.

Abstract: A spark plug having a center electrode with a cylindrical body with a tip at one end and a terminal near the other end with an insulator radially surrounding the center electrode. A ground shield surrounds the insulator and includes a ground electrode near one end, having a portion thereof with an annular opening disposed above and radially separated from the center electrode tip to form a radial spark gap, with a sealing portion disposed between the ground electrode and the other end of the ground shield for sealing the engine combustion chamber from the outside environment when the spark plug is installed. The ground shield can be formed from two parts which are deformed during manufacturing to be in mechanical engagement and securely holding the insulator in place. The spark plug can also have also have an integral or separate retainer for securing the spark plug to the engine.

Abstract: A spark plug for use in a combustion engine, which includes a spark plug body defining a central cavity; a electrode disposed within the cavity; a spring means disposed in one end portion of the central cavity; and a plate means operatively associated at one end with the spring means and adapted to communicate at its other end with the electrode whereby when the engine starts, the respective compression and explosion strokes move the plate means in one direction against the bias of the spring and in the opposite direction by the force of the spring, which in turn moves the other end of the plate in communication with the electrode in the same manner whereby combustion carbon collected on the electrode can be effectively removed.

Abstract: An electrode is secured and sealed in an insulator having a bore. The electrode has a shaft and an end plate, with the shaft having a cross section smaller than a cross section of the bore and the end plate having a cross section larger than the cross section of the bore. The shaft of the electrode is inserted into the bore and secured in the bore. A compressive force is applied between the end plate and an opposite end of the electrode, and an electrical current is applied between the end plate and the opposite end of the electrode to heat the electrode while the compressive force is applied. The electrical current and the compressive force are removed after being applied for a time sufficient to heat and expand the electrode so that, upon removing the electrical current, the electrode contracts to establish a seal between the electrode and the insulator.

Abstract: A spark electrode assembly and method of assembling same is disclosed. A ceramic housing having a cylindrical passage provides clearance for a conductive metal electrode. The electrode has a tubular body with rod shaped wires inserted at each end, the wires extending outwardly from the tubular body at each of its ends colinearly. During assembly, the wires are crimped into the tubular body in such a manner that the tubular body is deformed outwardly forming bosses. The bosses are of such a size as to cause an interference fit between the tubular body and the housing passage so that the electrode is captured within the housing. An impact force on the electrode forces the tubular body to expand radially outwardly, thereby further engaging the ceramic housing for holding the electrode in the housing. That part of the electrode body that is not in contact with the housing still has ample room to expand within the housing.

Abstract: By heating a glass sealing material, a center electrode is sealed and fixed within an axial bore of an insulator. Formation of a groove in a head portion of the center electrode makes it possible to protect the head portion of the center electrode from deformation under a pressure which is applied upon filling the glass sealing material in a powder form in the axial bore. The glass sealing material is therefore assured to flow to a peripheral side wall of a flange portion of the center electrode, thereby enhancing mechanical engagement between the center electrode and the insulator, that is, uniting strength for them. A spark plug is hence obtained with improved impact resistance and accordingly, with sufficient durability.

Abstract: An electrode assembly having a structure which minimizes stress cracks within its outer housing is disclosed. The outer housing is comprised of a ceramic tube having a bore therethrough which is coated with an epoxy material. An insulated electrical conductor with the wires contained therein in an exposed condition adjacent the end thereof is received in one end of the tube and is slidably advanced within the bore to the approximate midpoint of the tube. An electrode member is received in the opposite end of the tube and is slidably advanced within the bore so that its end contacts the exposed wires of the electrical conductor causing the ends of the wires to flare outwardly and grippingly engage the surface defining the bore in the tube. Subsequent heating of the electrode assembly causes the epoxy within the bore of the tube to bind the tube to the electrode member, the exposed wires and the insulated portion of the electrical conductor resulting in a solid, unitary construction for the electrode assembly.

Abstract: A spark plug containing a resistor which is a sintered body made from a mixture comprising coarse glass particles and fine glass particles, coarse ceramic particles and fine ceramic particles, and carbon black in special proportions is improved in noise signal suppression effect.

Abstract: In a center electrode structure for spark plug including a tubular insulator, the inner side of which has a stepped shoulder to provide a diameter-reduced bore therein; a center electrode having a flange, and concentrically placed into the insulator with the flange engaging against the shoulder, and with one end being axially through the bore so as to be exposed to outside of the insulator; the center electrode having a highly heat conductive core of copper or copper-based alloy which is encased into an enclosure made of oxidation and heat resistant nickel-based alloy; and the core providing its overall outer surface with a thin oxidation layer, so that the core is clad with the enclosure through the oxidation layer by means of extrusion.

Abstract: An improved electrode structure, particularly flame-front sensors, spark plugs and the like, wherein the center electrode, the insulating housing therefor, and an outer housing are dimensioned such that a small clearance space is provided between each of the parts; a fluid glue is inserted in the clearance or spacing provided in a fixation zone at one end of the structure by capillary action, so that the device is self-centering and heat sealed and not more than 3 mm in diameter, thus facilitating quick and easy installation in engine cylinder heads and combustion chambers.

Abstract: A resistor spark plug having, between a terminal screw and a center electrode, electrical conductive glass seals and a resistor glass seal therebetween, said electrical conductive glass seals containing carbon, one or more metals and glass and said resistor glass seal containing carbon, silicon carbide, glass, boron carbide or titanium carbide, and if desired a filler, has a small voltage coefficient of resistance and stable properties and is effective for reducing noise from an ignition system.

Abstract: A method of manufacturing an igniting electrode for a burner in which an insulating ceramic body has a longitudinal bore therethrough with projections or teeth provided over at least part of its length, and an electrically conducting metal stem, of complementary shape to the longitudinal bore absent the projections or teeth, is forced into the bore so that the projections or teeth make an imprint in the surface of the metal stem as it is being inserted into the bore.

Abstract: The spark plug has been designed so as to, be capable of being disassembled for cleaning, have a substantially full shield for the spark gap end of the center electrode portion, enable the center electrode to be readily replaced, if desired, enable partial cleaning of the spark plug gap area without removal of the spark plug from an associated engine, and have a substantially full gas seal defined between the base of the spark plug and the spark plug insulative sleeve.