Patent ID: 9103394
Filing Date: 2015-08-11
Classification: F16D

Abstract:
1. A brake drum comprising: a cylindrical drum body having a cylindrical outer surface, an open inboard end and an outboard end including a mounting plate, said mounting plate separated from the cylindrical outer surface by a shoulder portion; a cylindrical braking surface within said drum body having an area and defining a hollow interior of said brake drum; and an indentation defined in the shoulder portion of the drum body and extending inboard from the shoulder portion into said outer surface towards the open inboard end of said drum body, said indentation having an opposing pair of sidewalls, a back wall positioned in the cylindrical outer surface, a front opening positioned in the shoulder portion and opposing the back wall, an open end formed through said outer surface of the drum body and a closed end that is in radial alignment with the open end and a portion of the braking surface area, said indentation also having a depth measured from the cylindrical outer surface of the drum body, and the corresponding open end of the indentation, to the closed end of said indentation such that when said braking surface is worn away beyond a pre-defined braking surface diameter, the hollow interior of said brake drum is visible through the open end of the indentation; and wherein said depth is at least co-level with the pre-defined braking surface diameter.