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US 8,146,340 B2Granted
Link chain
AssigneeDaido Kogyo Co., Ltd.
InventorsYoshihiro Shimada, Nobuyuki Matsui
Life of this patent
Estimating the term…
Abstract
A bush is pressed into a link plate in a turning link rank that turns relatively with a pin. The bush is molded into a seamless cylindrical shape by cold-forging and is coated with a metal carbide layer formed by cementation of chrome, vanadium and other metals and having Vickers hardness of 1300 Hv or more similarly to the pin. Afterwards, the bush is treated by a quenching, tempering or isothermal transformation process. Thereby, wear resistance of the pins and the link plates of a silent (link) chain is improved, productivity is improved and associated costs are reduced.
Claims7
A link chain comprising:
- non-turning link ranks each having a plurality of first link plates each disposed in a width direction of said link chain and having a pair of pinholes;
- turning link ranks each having a plurality of second link plates each disposed in the width direction of said link chain and having a pair of bush holes;
- a bush disposed within each of the bush holes;
- pins linking said non-turning link ranks with said turning link ranks alternately by being inserted into the pinholes of said first link plates and the bushes of said second link plates;
- each first link plate not turning relatively with respect to each pin linking a respective non-turning rank with a respective turning rank so as to be fixed with respect to the pin thereby so linking the respective ranks;
- each second link plate being turnable relatively with respect to each pin linking a respective non-turning rank with a respective turning rank;
- a surface of each of said pins is coated by a metal carbide formed of at least one of chrome, vanadium, niobium, titanium, zirconium, tantalum, molybdenum and tungsten by means of cementation and having Vickers hardness of 1300 Hv or more;
- and
- each bush is molded into a seamless cylindrical shape by cold-forging carbon steel or alloy steel containing carbon by 0.2 wt % or more, is coated with a metal carbide formed of at least one of chrome, vanadium, niobium, titanium, zirconium, tantalum, molybdenum and tungsten by means of cementation and having Vickers hardness of 1300 Hv or more and is treated further by a quenching, tempering or isothermal transformation process.
6 more elements
Dependencies are inferred from the claim text.