Abstract: A piston ring has a gap defined by ring gap faces oriented toward one another and a nominal outer radius assumed by the piston ring in a closed position in which the piston ring is in an installed state in an engine cylinder having a radius equalling the nominal outer radius of the piston ring. The piston ring has first length portions extending from both ring gap faces and having a central angle of at least 15.degree. and less than 25.degree. and second length portions immediately adjoining each respective first length portion and having a central angle of approximately 10.degree.. In the installed state the first length portions have a radius of curvature equalling the nominal outer radius and the radius of curvature of the second length portions is smaller than the nominal outer radius.

Abstract: A cover assembly for an internal combustion engine includes sleeves that are connected with a cover member by rubber bodies. The rubber bodies decouple the cover member from structure-borne sound from the engine. Depending on its configuration, the cover assembly may be used as an oil pan or a valve hood. The cover assembly is made from a cover blank which includes the cover member, the sleeves, and webs which connect the sleeves to the cover member. The cover blank is placed in a mold. The webs break and the sleeves are axially displaced with respect to the cover member as the mold is closed. An elastomer material is then injected into the mold to form the rubber bodies.

Abstract: A housing cover for closing an open side of a housing includes a dish-shaped sheet metal cover body provided with a central opening for the passage of a shaft; a bottom plate forming part of the cover body and having opposite first and second radial surfaces; and a plurality of spaced holes in the bottom plate for providing passages for respective bolts, each having a bolt head with an underface, for securing the cover body to the housing. In an installed state of the housing cover, the first radial surface of the bottom plate is oriented towards the housing and the second radial surface of the bottom plate is oriented towards the underface of the respective bolt.

Abstract: An impregnated flat gasket useful as a cylinder head gasket for an internal-combustion engine, includes a fiber mat comprised of from about 2 to about 20 weight percent of a synthetic organic fiber; from about 10 to about 70 weight percent of a first inorganic filler which has a grain size having a maximum of 0.01 mm and which has a specific surface area having a maximum of 30 m.sup.2 /g; from about 10 to about 70 weight percent of a second inorganic filler which is composed of particles having a shape which is one of needle-shaped and globular, which has a grain size having a maximum of 0.01 mm and which has a specific surface area ranging from 50 to 350 m.sup.2 /g; from about 0.5 to about 1 weight percent of zinc oxide; and from about 3 to about 10 weight percent of a nitrile butadiene latex. The impregnated fiber mat material can be punched into gasket blanks without problems.

Abstract: An apparatus for inserting an expander ring into an inner circumferential groove of a split piston ring includes a first magazine for storing a stack of piston rings; and a second magazine for storing a stack of expander rings. The second magazine has a discharge end and a longitudinal axis coinciding with a longitudinal axis of the expander ring stack. There are further provided a device for displacing a piston ring from the first magazine into axial alignment with the longitudinal axis of the second magazine at the discharge end thereof; a spreader device for radially outwardly spreading the piston ring positioned at the discharge end; and a pusher for pushing an expander ring from the second magazine parallel to the longitudinal axis into the piston ring spread-open by the spreader device.

Abstract: A valve stem seal assembly for installation about a valve stem surrounded by a valve guide includes a sleeve-like elastomer body having the following four components: (1) an annular, outer, oil-sealing lip for sealingly surrounding the valve stem in the installed state of the seal assembly; (2) an annular, inner, gas-sealing lip for sealingly surrounding the valve stem in the installed state of the seal assembly; (3) a diaphragm situated axially between the oil-sealing lip and the gas-sealing lip and being connected to the oil-sealing lip; and (4) a generally cylindrical mounting part for surrounding and engaging the valve guide in the installed state of the seal assembly. The gas-sealing lip is directly connected with the mounting part externally of a region of the diaphragm.

Abstract: A device is provided for finely working exterior circumferential faces of self-tensioning piston rings which are combined into a packet. The device includes a cylindrical sleeve having an interior wall surface against which the circumferential faces of the rings lie under their own tension. Two discs are disposed between which the rings are arranged in the sleeve with a slight axial spacing. The packet of rings is rotatable relative to the sleeve and movable back and forth within the sleeve, with at least one of the discs being pivotal about the longitudinal axis of the sleeve. A mechanism is provided for pivoting the one disc about a pivot angle that is variable and arrestable for subjecting the rings to a tilting movement with the sleeve.

Abstract: A lip seal ring for circumferentially contacting and sealing a shaft movable relative to the lip seal ring includes an elastomer ring having a sealing lip and an adhering face and a stiffening ring made of a deformation-resistant material. The stiffening ring is bonded to the elastomer ring at the adhering face. The stiffening ring is made of a phenolic resin, a polyamide resin or a polyimide resin. The elastomer ring is made of an oil-resistant elastomer based on a nitrile-butadiene rubber or a derivative thereof, and polyethylene or polypropylene.

Abstract: An assembling device receiving a valve-actuating subassembly intended for installation about a valve stem in an internal-combustion engine. The subassembly includes a valve spring having opposite first and second ends and a valve spring retainer abutting the valve spring at the first end thereof. The assembling device includes a holder abutting the valve spring retainer; and an axial extension surrounding the holder and being axially displaceable relative thereto. The axial extension includes a stop at a first end of the axial extension for preventing the holder from separating from the axial extension and a hold-back arrangement at a second end of the axial extension for releasably engaging the valve spring at the second end thereof, whereby the stop and the hold-back arrangement together releasably secure the subassembly to the assembling device.

Abstract: Soft material flat gasket useful as an exhaust flange gasket, a cylinder head gasket or a secondary gasket for internal-combustion engines includes a porous soft material and a crosslinked impregnating agent included in the porous soft material. The crosslinked impregnating agent is comprised of a silicone resin and is the crosslinked product of at least one liquid polysiloxane having reactive hydrogen groups. Crosslinking of the at least one liquid polysiloxane proceeds in the presence of an effective amount of a catalyst, which catalyst is introduced into the porous soft material prior to introduction therein of the at least one liquid polysiloxane according to the inventive method of manufacture.

Abstract: A piston-and-ring assembly includes a piston having a circumferential groove which has an upper side wall and an opposite lower side wall; and a piston ring received in the groove and having opposite radial faces extending obliquely with respect to the side walls. The piston ring engages, with an axial bias, the upper and lower side walls with an annular marginal surface portion forming part of each radial face of the piston ring and extending substantially parallel to the side wall with which it is in engagement.

Abstract: An impeller-and-seal unit for a liquid pump includes a plastic impeller, a metal hub affixed to the impeller and arranged to receive and contact a pump shaft, a slide ring seal assembly including a slide ring and a counterring received in a recess of the impeller and being in sliding contact with the slide ring. The metal hub has a radial extension which projects radially outwardly and which is received in the recess, forming a bottom thereof. The counterring has a radial end face which is in a direct contact with the radial extension.

Abstract: An article for use as a shaft sealing ring for sealing a fluid medium includes an elastomeric body, a housing member, and a sealing lip having a sealing edge; the sealing edge, when installed about a shaft, being radially deformed and contacting a surface of the shaft along a running zone having a first end adjoining the fluid medium and a second end adjoining the environment to be sealed from the fluid medium; the sealing edge, when in a non-installed condition, having an annular surface of varying inner diameter along the running zone; the smallest of the varying inner diameter lying closer to the first end than to the second end.

Abstract: A flat sealing gasket includes a mat of non-woven material having opposite faces; a polymerized impregnating agent distributed with the material and an overlay on at least one of the mat faces. The overlay which comprises a hardened, pressure-resistant polymer material is sunken into the mat to a substantial extent of the mat thickness.

Abstract: A piston ring whose contour deviates from the circular shape, and in particular an elliptical or oval piston ring, which, when seen in the circumferential direction, has regions that, in the installed state as well as in the operating mode, exert less radial contact pressure than the remaining surface regions in order to reduce wear of and leakage by the ring.

Abstract: A mounting aid arranged for receiving a valve-actuating sub-assembly intended for installation coaxially about a valve stem. The sub-assembly includes a valve coil spring, a spring retainer having a central aperture and a split collar. The mounting aid has a closing disc having an outer circumference and being arranged for engaging an outer radial surface of the spring retainer coaxially therewith; an axial extension attached to the closing disc at the outer circumference thereof; and hold-back means formed on the end of the extension for releasably securing the sub-assembly to the axial extension.

Abstract: A slide ring seal for use in a liquid pump, for example, employs an open-ended seal housing and a carrier body which is urged away from the seal housing by a spring. A rubber ring and a slide ring are mounted in the carrier body. The slide ring slidably engages a rotating running ring on a pump impeller, for example, to form a seal. The rubber ring establishes a seal between the carrier body and the slide ring and between the carrier body and the seal housing.

Abstract: A method of making self-tensioning rings, including the steps of circumferentially machining an out-of-round ring blank on inner and outer surfaces thereof and subsequently cutting a ring segment out of the ring for obtaining a ring gap therein; measuring a circumferential contour of the ring subsequent to the machining step; and calculating the circumferential length of the ring segment and a cutting angle for removing the ring segment from the ring as a function of data obtained in the measuring step.

Abstract: Solid particles of primarily hard substances, solid lubricants, ductile metals or their alloys and/or molten polymers are embedded in a network of cracks of hard chromium coatings to attain improved physical characteristics, primarily to increase wear resistance, sliding behavior, ductility and corrosion resistance.The chrome plating process takes place in a microcrack-forming chrome-plating electrolyte with solid particles dispersed therein and with one-time or repeated current reversal so that, if the workpiece is connected to the anode, the network of microcracks in the chromium coating is widened and solid particles are embedded within the cracks. Preferred uses are as coatings on the bearing surfaces of piston rings or cylinder bearing sleeves for internal-combustion engines.

Abstract: A valve stem sealing assembly includes a valve spring, a valve spring retainer, and a valve spring seal which is releasably connected either directly or indirectly to the valve spring retainer. Such a valve stem sealing assembly can be installed as a unit during mass production of engines. In one embodiment the valve spring retainer is provided with a sleeve which releasably supports the valve stem seal. Another embodiment includes a protection element on which the valve spring rests to keep it from digging into the metal of the engine. Both the protection element and the valve spring retainer are provided with sleeves in the second embodiment, and these sleeves are releasably connected. The valve stem seal is lodged in the sleeve of the protection element. In both embodiments the releasable connection, which may be provided by force-fitting one element into another, is released after installation of the assembly.