Specification for a composite steel brake drum under the Holden & Hunt Patent.
| Identifier | ExFiles\Box 120\3\ scan0041 | |
| Date | 1st May 1938 | |
| SPECIFICATION OF COMPOSITE STEEL BRAKE DRUM. (Holden & Hunt Patent) [Stamp: RECEIVED 1 E 1938] The rim is made from rolled section of special analysis (.4/.45% carbon) steel, normal strength 40/45 tons, heat treated 55/60 tons per sq.in.tensile. Disc is of best quality mild steel. This is spigoted into the rim and secured by means of screwed dowels, the dowels and intermediate points being electrically welded. The design offers the following advantages:- (I). Greater strength and rigidity for a given weight of material. (2). Increased reliability over cast materials. (3). Narrower drum without reducing width of shoes, thus saving weight. (4). Reduced distance from centre of shoe to supporting flange, thus reducing tendency to tilt or distort. This is of special importance with servo shoe mechanisms. (5). The surface does not 'pick-up' or acore, but retains a polished condition. (6). Concentricity is not destroyed after heating. (7). Immunity from brake squeak. (8). Drums supplied in rough state are partly machined, requiring very small finishing costs. The merits claimed have been proved over extensive tests. Pratt & Manley, Consulting Engineers, Guildhall Buildings, Navigation Street, Birmingham. | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).