Patent ID: 7325659

Claim:
An improved drum brake comprising: a drum having an outer generally cylindrical circumferential wall having inner and outer sides and an inner braking surface and a side wall plate mounted on and extending between the inner side of said outer circumferential wall; a braking mechanism including at least one brake shoe having an arcuate brake pad mounted thereon and brake actuating means operative to force the arcuate brake pad into frictional contact with the inner braking surface of outer circumferential wall; and at least two diagonal grooves formed in said inner braking surface of said outer circumferential wall, each of said at least two diagonal grooves having a base and a generally V-shaped or U-shaped cross-sectional shape and extending substantially across the entire width of said outer circumferential wall, each of said at least two diagonal grooves extend at an angle relative to the rotational axis of said drum, said angle being between fifty degrees and seventy degrees (50° and 70°), said at least two diagonal grooves each further include slight outwardly increasing depth for the base of said at least two diagonal grooves relative to said inner braking surface with the change in depth being generally uniform between said side wall plate and said outer side of said outer circumferential wall, said at least two diagonal grooves operative to transfer liquid from within said drum which falls into said at least two diagonal grooves out of said drum as the liquid is forced rearwards and outwards out of said drum within said at least two diagonal grooves due to the rotation of the drum.