(From Alloy-Artifacts) In 1946 Plomb ran into an odd problem: it was sued for trademark infringement by Fayette R. Plumb, Inc., a company making hammers and other striking tools. According to an article in the December 6, 1948 issue of Time magazine, the roots of the dispute went back to 1926, when Plumb objected to an attempt to register Plomb as a trademark. Apparently the companies negotiated an agreement at the earlier time, but later actions by Plomb were deemed to violate the terms.
As a result of this trademark dispute, Plomb was required to change the brand name marked on their tools, and chose "PROTO" (from "PROfessional TOols") as the new name. In 1948 Plomb started marking tools with the "PROTO" mark (this time making sure to register the trademark), and by 1950 the Plomb name had disappeared from its tools.
Although this forced name change may have been a nuisance at the time, the company itself was largely unaffected. Plomb continued operating as the Plomb Tool Company for a number of years after 1950, making the same tool models to the same specifications as it had before, but now marked "Proto Los Angeles".
