An Outstanding Brake
Page 76
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A CCORDING to patent No. 775,052, Pt brake fade, particularly in large vehicles, is becoming more and more of a problem in design. This is even true, the patentees state, of disc brakes, though not so serious as with drum brakes. The patent describes a cornplete water-cooling system for brakes, incorporating hollow shoes, piping and a radiator. (R. Sanford, Tuttle Road, Woodbury, Conn., U.S.A. and others.) Not only are the shoes water-cooled, but they carry no friction facing, this being attached to the drum instead. The drawing shows a typical brake layout in which. a pump (1) circulates water through a radiator (2) and the hollow shoes (3). The annular friction lining (4) is a complete ring and is bonded to
the drum. .
An important feature of the scheme is that the shoe contact faces are made of pure, or nearly Pure, copper. This is not only an excellent .conductor of heat, but appears to have other properties that render it suitable. Both silver and aluminium were tried, but copper was found to give the best results. The patent gives some very impressive figures relating to tests made with the system, indicating virtually complete freedom from fade.