Abstract: A low friction roller chain, bushing chain or silent chain is composed of links in which at least some of the link plates have convex and/or grooved edge surfaces adapted to slide on the surface of a chain guide.

Abstract: Connecting pins in a roller chain are chromized by a diffusion penetration treatment, that results in inner and outer chromium carbide layers on the steel base material. The inner layer contains Cr7C3, and the outermost layer, which is thinner than the inner layer, contains Cr23C6. The surface roughness of the outer layer is reduced by barrel polishing, without removal of all of the Cr23C6-containing layer.

Abstract: In an endless silent chain composed of alternating guide link rows and joint link rows connected by connecting pins, each guide link row is composed of a stack of three, centrally located, link plates and two outer guide plates, and each joint link row is composed of two pairs of link plates in abutting, side-by-side relationship. The pairs of link plates of the joint link rows extend into the spaces between the guide plates and the centrally located stack of each of two adjacent guide link rows.

Abstract: Occasional abnormal wear elongation, which occurs in a silent chain when exposed to lubricating oil in a deteriorated condition due to oxidation, is avoided by polishing the inner link plates of the chain to a surface roughness of 0.5 ?m Rz or less, chromizing the inner link plates, forming a vanadium carbide layer on the connecting pins of the chain, and then polishing the connecting pins to a surface roughness of 0.5 ?m Rz.

Abstract: In a roller chain having cylindrical pins rotatably fitting into bushings on which the rollers are disposed, a vanadium carbide layer formed on the cylindrical pin surfaces avoids abnormal wear elongation of the chain, and allows smooth articulation of the chain over a long period of time, even when the lubricating oil is in an extremely deteriorated condition due to oxidation.

Abstract: In a newly manufactured roller chain, the pitch measured from one to the other of the two adjacent bushings of any two successive inner links of the chain, is smaller the pitch, measured from one bushing to another of the two bushings on any one of said inner links of the chain, by an amount corresponding to the initial elongation of the chain.

Abstract: A cutting method for cutting an optical lens and/or a molding die therefor includes rotating the optical lens and/or the molding die about the optical axis, moving a cutting blade in a direction perpendicular to an optical axis to cut the optical lens and the molding die, and varying the feed pitch of the cutting blade in the direction perpendicular to the optical axis in accordance with the position of the optical lens and/or the molding die in the radial direction.

Abstract: To provide a roller chain, which does not generate abnormal wear elongation and smoothly articulately slide for a long period of time even if the roller chain is used together with an extremely deteriorated lubricating oil having a high degree of oxidation. In a roller chain in which both ends of a bush are press-fit to bush holes of a pair of inner plates, both ends of a pin loosely penetrated into the bush are press-fit into pin holes of a pair of outer plates disposed outside the both pair of inner plates and a roller is fit onto said bush, a material of said bush is carburized stainless steel and a vanadium carbide layer is formed on the surface of the pin.

Abstract: In a roller chain having cylindrical pins rotatably fitting into bushings on which the rollers are disposed, a vanadium carbide layer formed on the cylindrical pin surfaces avoids abnormal wear elongation of the chain, and allows smooth articulation of the chain over a long period of time, even when the lubricating oil is in an extremely deteriorated condition due to oxidation.

Abstract: A cutting method for cutting an optical lens and/or a molding die therefor includes rotating the optical lens and/or the molding die about the optical axis, moving a cutting blade in a direction perpendicular to an optical axis to cut the optical lens and the molding die, and varying the feed pitch of the cutting blade in the direction perpendicular to the optical axis in accordance with the position of the optical lens and/or the molding die in the radial direction.

Abstract: A holder is constructed of a cylindrical member made of a metal and an inward flange member made of a diffusion transparent member. The inside of the cylindrical member is sectioned into a tapered area whose inside diameter decreases downward, and a small-diameter cylindrical area and a large-diameter cylindrical area. The inward flange member is bonded to the bottom end of the small-diameter cylindrical area.