- Country of manufactureGermany
Spring corrosion-proof washer (Grover's washer, Grover) — a cutting round washer which ends are located in the different planes. Serves for prevention of self-unscrewing of threaded connections due to elastic deformation of a washer under loading.
According to GOST 6402 washers can be made four types (easy, normal, heavy, especially heavy). Difference of types consists in sizes of cross section of a washer and size of force necessary for its elastic deformation. Washers can be made of spring steel of brands 65G, 70, 3Х13. Production from bronze (brand of BrKMts of 3-1 GOST 18175-78) or other color alloys is possible. Hardness of steel washers has to be 40 — 48 HRC, bronze — not less than 90 HRB.
Everyday names of a washer — "Grover's washer", "engraver", come from a surname of John Grover [en] (1836 — 1892) — the English engineer who invented this type of washers  . According to GOST 27017 the term "Grover's washer" is an inadmissible synonym of the term "spring washer" and should not be applied in all types of documentation and literature falling within a coverage of standardization or using results of this activity.
Standards of spring washers;
- GOST 6402-70 * — Washers spring. Specifications;
- DIN 127 B — Stainless lock washer with smooth ends (a spring washer with the dulled edges);
- DIN 127 A — Stainless lock washer with tang end (a spring washer with sharp edges);
- DIN 128 A — Curved spring lock washers (spring washer convex);
- DIN 128 B — Wave spring lock washers (spring washer wavy);
- DIN 7980 — High collar spring lock washers, spring steel for socket head cap screws (a washer spring for screws with a cylindrical head).