Abstract: An improved method is disclosed for forming a composite spark plug electrode having a thermally conductive metal core embedded within a corrosion-resistant metal sheath. Initially, a composite billet is formed by positioning a mass of the thermally conductive metal within a cup formed from the corrosion-resistant metal having a closed end and an open end. The corrosion-resistant metal at the open end of the cup extends further than the thermal conducting metal. The composite billet is passed open end first through an extrusion orifice. A head may be formed on the end of the resulting extrusion for welding to a wire terminal or an end of a wire terminal is positioned within the open cup end prior to passing the cup through the extrusion orifice for mechanically bonding the extrusion to the terminal. Excess metal on the end of the cup may be removed from the resulting composite electrode or it may be sheared from the electrode and repositioned axially along the electrode to form a shoulder.

Abstract: A method for assembling a spark plug 20, 66 which includes providing a ground electrode 24 on a spark plug shell 22 having a predetermined final configuration and position and then mounting an insulator 34 in the shell. The distance from a step 38 in an insulator bore 37 to the ground electrode is measured. Based upon this measurement and a desired dimension for a spark gap 56, the dimension on a center electrode 48, 68, 74 between a shoulder 50, 76 and a tip 52, 80 is adjusted so that when the center electrode is disposed in the insulator bore with the shoulder seated on the bore step, the tip forms the desired spark gap with the ground electrode. The center electrode then is assembled into the insulator.

Abstract: A pneumatic switch (25) responsive to the vacuum in a closed crankcase (20) of a reciprocating piston engine (15) for indicating when there is less than a predetermined quantity of oil (21) in the crankcase. The switch includes a housing (30) defining a cylinder (35), a closed end (48) and an open end (74). A piston (36) reciprocates and rotates in the cylinder through a path determined by a cam (51) and a follower (52). Crankcase vacuum is applied to a chamber (47) between the piston and the closed housing end to move the piston against a calibrated spring (50). An electric switch (70, 71 and 76) indicates when the piston is in the portion of its path of motion when the engine is operating and there is less than the predetermined quantity of oil in the crankcase.

Abstract: A method for producing a composite spark plug electrode is disclosed. The method comprises forming a first metal into a cup having an open end, a closed end and a wall surrounding a central opening which extends a distance z from the closed end to the open end. The method also comprises forming, from a second and different metal, a right circular cylindrical core sized to be received in the central opening in close fitting relationship with the wall therearound, and extending from the closed end toward the open end a distance less than z, and positioning the core in the central opening, thereby forming a composite billet having first and second ends corresponding, respectively, with the open and closed ends of the cup. Finally, a portion of the composite billet is extruded, second end first, through an extrusion orifice of a die with a force applied to the first end of the composite billet by an end of a tool.

Abstract: A method for sensing when the quantity of oil in the crankcase of a reciprocating piston engine is inadequate for proper lubrication while the engine is operating. During engine operation, the crankcase gas pressure cycles between positive and negative values as the piston reciprocates. Positive crankcase gas pressures are vented through a check valve. The resulting cyclic vacuum in the crankcase has a peak and average magnitude which is a function of the quantity of oil in the crankcase. For a constant speed and substantially constant load engine, the crankcase vacuum can be used to indicate the approximate quantity of oil in the crankcase. For constant or variable speed and load engines, a drop in the crankcase vacuum below a predetermined level can be used to automatically stop the engine prior to damage by inadequate lubrication.

Abstract: A silicon-talc sealing material is disclosed. The sealing material is made up of about 15 to 30 percent by weight of silicon metal powder and about 85 to 70 percent by weight of talc. It has been found to be admirably suitable for sealing around the center wire of spark plugs in which the sealing material is subjected to temperatures of about 900.degree. F. or higher. In such applications, the sealing material is unexpectedly advantageous by comparison with previously known materials, because it has significantly higher holding power, because it allows significantly less gas leakage, or because it has both advantages.

Abstract: This invention relates to spark plugs for internal combustion engines and is particularly directed to a center electrode having a sparking tip composed of a precious metal and to the method of making the same. The known advantage of the use of a precious metal electrode is that considerably greater spark plug life is achieved. The invention achieves the advantage while greatly reducing the mass of precious metal employed. A further feature of the invention is the co-planar disposition of the end of the center electrode and its supporting insulator.