Abstract: Oil scraping piston ring of profiled steel having punched-in oil vent holes. To keep at a minimum the bulging at the holes developed during coiling, the oil vent holes are given an elliptical or rhombic outline.

Abstract: Friction-reducing coating compositions and coated machine parts having a wearing surface provided with coatings of same. In one embodiment, the coating composition includes from 10 to 25 weight % molybdenum metal; from 55 to 70 weight % nickel alloy; and from 5 to 25 weight % chromium carbide Cr.sub.3 C.sub.2. In a second embodiment, the coating composition includes from 25 to 45 weight % molybdenum metal; from 45 to 60 weight % nickel alloy; and from 5 to 25 weight % of a hard substance selected from chromium metal, chromium carbide Cr.sub.23 C.sub.6 and molybdenum carbide Mo.sub.2 C. Preferably the nickel alloys contain from 73 to 95 weight % nickel and have a melting point below that of nickel metal. Preferably the friction-reducing coating is applied to a wearing surface by plasma flame spraying. These coatings impart excellent wear resistance to the wearing surface, while lowering wear of counter-running faces.

Abstract: A piston-and-ring assembly includes a generally cylindrical piston, a circumferential groove provided in the piston and having a bottom and two radial flanks forming opposite sides of the groove; and an expander spring ring accommodated in the groove and including a plurality of generally radially extending tongues arranged in a circumferential series. Each tongue has, at a radially inward end, a leg portion extending at a first angle other than zero to the respective tongue from which it extends. An oil scraper annular lamina is situated in the groove and is supported axially by the tongues and is abutted radially by the leg portions. An extension forms part of each leg portion and is oriented thereto at an inclination. Each extension has a length which extends substantially from one of the flanks to the other.

Abstract: An oil scraper piston ring assembly includes an oil scraper ring received in a piston groove and being in circular contact with a first side wall of the groove; and a spring ring received in the groove between the oil scraper ring and a second side wall of the groove. The spring ring has circumferentially distributed resilient tongues oriented alternatingly radially inwardly and radially outwardly. The spring ring has a radially outer circular part situated axially adjacent the oil scraper ring and a radially inner circular part bent with respect to the radially outer circular part and extending at least partially radially adjacent an inner periphery of the oil scraper ring. The oil scraper ring is a steel band ring of relatively small axial height, the spring ring is a resilient band ring also of relatively small axial height, and the oil scraper ring and the spring ring have approximately identical thicknesses of material.

Abstract: A piston ring assembly has a ring-shaped expander spring composed of an annular body defining an axial direction and presenting a circumferential main bending region and a plurality of resilient tongues extending radially outwardly from the main bending region and adjoined, adjacent the main bending region, by generally axially extending parts of the annular body. The assembly further has a lamina lying, at least in part, on the tongues and is radially supported by the axially extending parts. The main bending region is disposed radially inwardly of the lamina.

Abstract: In a cylinder head gasket for an internal-combustion engine, composed of a disc of fibrous and/or porous soft material provided with passages, and a metallic casing extending around one such passage and presenting two arms each disposed at a respective side of the disc with at least one arm being angled in the direction toward the soft material, and a saturating agent which is plastic or elastic when installed and which fills the pores of the soft material except for the region underneath the casing, the angled portion of the at least one arm has the configuration of an annular recess directed toward the interior of the disc in the immediate vicinity of the end of the one flange arm.

Abstract: A porous soft material sealing gasket comprising an asbestos fiber web with a multiplicity of perforations. The perforated web is impregnated with an impregnating agent that at least partially fills the free pores of the web by penetrating through the perforations.

Abstract: A gasket made of a fibrous and/or porous material is impregnated with a liquid saturating agent consisting essentially of an organic, synthetic and completely polymerizable liquid that does not contain agents which will evaporate during polymerization of the liquid.

Abstract: A spacer-expander member for holding one or two cylinder-engaging rails in a groove in a piston is formed to present a plurality of radially inwardly-directed spacer feet which are so located that they engage the groove bottom in a region spaced from the groove sides.

Abstract: An axially and radially clamping spreader ring for an oil scraper piston ring, comprises a profiled metal band which has been made resilient in the circumferential direction by corrugations and/or cuts. The two ends of the metal band abut against one another and the metal band is provided in the area of one side with axial and radial supporting faces to accommodate at least one band-shaped scraper ring. A plurality of radially outwardly extending protrusions are distributed over the circumference of the band in the vicinity of the side of the spreader ring which is axially opposite the side which accommodates the scraper ring. The protrusions are separated from one another by wide lubricating channels and, when installed, contact the cylinder wall.

Abstract: A piston ring formed of an annular, cross-sectionally bent metal strip has a series of circumferentially distributed slots extending in a generally axial orientation from edges of the strip. The slots are in an overlapping relationship when viewed circumferentially for defining a series of circumferential, resilient webs. The webs have web portions that are readily deformable to bending forces.

Abstract: An expander spring for supporting an oil scraper ring in a groove of a piston is constituted by a sheet metal ring having an axis and forming an annular channel of generally U-shaped cross section. The channel has two side walls, forming, respectively, a radially inner and a radially outer, axially oriented side of the expander spring. The channel further has a base interconnecting the side walls and an open side opposite the base. A plurality of circumferentially distributed slots are provided in the side walls for increasing the resiliency of the expander spring in the circumferential direction, and a plurality of axially projecting support feet are carried by the free end of the radially inner side of the expander spring for supporting at least one oil scraper ring.

Abstract: A cylinder head gasket for internal combustion engines comprises at least one layer of a soft material having pores which are enriched with an impregnating agent and edges which are bordered by a casing. The pores of the soft material underneath the flange are kept free of impregnating agent.