Abstract: The present invention provides liquid phase diffusion bonding alloy foils capable of bonding in an oxidizing atmosphere, which can ensure joints with a homogeneous structure and adequate tensile strength in air in a short period of time using various alloys or Fe-based materials as materials to be bonded; specifically, they are Ni-based liquid phase diffusion bonding alloy foils with compositions comprising as essential components in terms of atomic percent, the diffusion elements B or P at 1.0-20.0% or B and P each at 1.0-20.0%, and Si at 0.5 to ≦15% or 0.5 to <10% and V at 0.1-20.0%, with the remainder substantially Ni and unavoidable impurities, and having a thickness of 3-100 &mgr;m. If necessary, one or more types of Cr, Mn or Mo, Co, and/or one or more types of W, Nb and Ti may be selectively included as appropriate. Compositions with a substantially amorphous crystal structure are most effective.

Abstract: This invention provides an oil well pipe threaded joint capable of preventing looping and squeezing of a soft synthetic resin ring and consequently, preventing catching of a tool during a logging operation and damage such as corrosion by a corrosive fluid, the oil well pipe threaded joint employs the construction wherein a soft synthetic resin ring is interposed between distal end surfaces of pins, each step surface of a shoulder portion on an inner peripheral side of a coupling and a step surface of each pin are brought into abuttment, and each inside thread of the coupling of the coupling and each outside thread of each pin are engaged, wherein a compressive ratio of the soft synthetic resin ring in an axial direction falls within the range expressed by an inequality 18,000/E≦compressive ratio (%)<0.038−1×1n[1−{(d1−d2)+0.36}/0.

Abstract: In a rubber crawler, lags are generally are formed on the outer surface of an endless belt-like elastomer, and rubber projections for transmission of driving force and prevention of the rubber crawler from coming of off from a wheel are formed on the inner surface of the elastomer at regular pitches. Rein forcing cord layers are embedded in the elastomer along its longitudinal direction. An abrasion resistant member is embedded in the rubber projection along the width direction of the rubber crawler. Its both end portions are exposed at the sides of the rubber projection. The abrasion-resistant member has a central portion having a small diameter and a pair of end portions connected to the ends of the central portion and having a large diameter. In the exposed portion of the end portion which is exposed at the side surface of the rubber projection, its most interior portion in the radial direction is positioned above the base portion of the rubber projection.

Abstract: An object of the present invention is to provide galling resistance to a threaded joint used for an oil well pipe. On a thread portion and a metallic sealing portion of the joint, there is provided a manganese phosphate chemical formation coating layer, or alternatively there are provided a nitriding layer of 1 to 20 .mu.m thickness and a manganese phosphate chemical formation coating layer of 5 to 30 .mu.m thickness, and also there is coated a solid lubricant which contains powder of molybdenum disulfide or tungsten disulfide and also contains one of epoxy resin, furan resin and polyamide resin as an essential component, and a ratio of composition is maintained at a specific value, so that a solid lubricant coating layer of 10 to 45 .mu.m thickness can be formed by heating.Due to the above surface treatment, even when the frequency of repetition of fastening and unfastening of the joint is increased, the occurrence of galling can be prevented over a long period of time.

Abstract: The present invention provides an Fe-based alloy foil for liquid phase diffusion bonding of Fe-based material by enabling bonding in oxidizing atmospheres at relatively high bonding temperatures to minimize thermal influence on the base material (the material to be bonded) and, thereby, ensures production of a bonded joint having a uniform microstructure and a good bonded joint strength and enables reduction in the bonding time. The Fe-based alloy foil contains, as essential elements, one of 1.0 to 20.0% P and 1.0 to 20.0% B, 1.0 to 20.0% Si, and 0.1 to 20.0% V, in terms of atomic percentage, the balance substantially of Fe and unavoidable impurities, and has a thickness of 3.0 to 100 .mu.m. Alternatively, the Fe-based alloy foil contains, as essential elements, 1.0 to 20.0% P, 1.0 to 20.0% Si, and 0.1 to 20.0% V, and 1.0 to 20.0% B, in terms of atomic percentage, the balance substantially of Fe and unavoidable impurities, and has a thickness of 3.0 to 200 .mu.m.

Abstract: A metallic core for a rubber track includes wing portions to be embedded in an elastic member of the rubber track, an engaging portion at the center of the core for engaging a driving sprocket, and a pair of protrusions provided on both sides of the engaging portion and projecting from the inner circumferential surface of the rubber track. Each of the protrusions is provided with at least one extension extending in the longitudinal direction of the rubber track, and the top surfaces at the extension and at the center of the protrusion for rolling an idler thereon are connected to each other with a surface gently inclined downward toward the center of the protrusion, thereby maintaining idlers rolling on the metallic cores of a rubber track at a substantially constant level without upward and downward movements.

Abstract: A threaded joint for oil-well pipe comprises a box having an internal thread, a pin having an external thread, a metal-to-metal sealing contact provided at the unthreaded tips of the box and pin, and a film of grease applied on the surface of the internal and external threads. The cross-sectional area of a void containing the screw axis left between the meshed internal and external threads is at least 0.6 mm.sup.2 per pitch.