The Mach3 promises a close shave

Gillette alleges that Quattro, a four-bladed razor due to go on sale next month, infringes its patent by using the same "progressive blade geometry" design as Gillette's best-selling Mach3.

Energizer, which makes Quattro, "is deliberately attempting to capitalize on the superior performance of Mach3, the world's number one shaving product," said Gillette spokesman Eric Kraus.

"It's hard to imagine that progressive blade geometry was included in the Quattro product by accident," he added.

Energizer said it had no immediate comment on the lawsuit.

Competition

The Mach3 razor, which notched up sales of more than $2bn last year, claims to offer a cleaner shave by allowing each blade to move progressively closer to the beard hair.

The lawsuit seeks a court order to prevent Energizer from launching its four-blade razor, as well as unspecified damages, throwing a potential spanner into Energizer's plans.

Both Energizer and Gillette have embarked on expensive advertising campaigns for their products.

Gillette dominates the world's shaving market, but is facing renewed competition from Energizer since it bought the Schick-Wilkinson Sword brands.