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).
List of modifications and improvements made to a brush holder for a 40/50 HP starter motor.
| Identifier | WestWitteringFiles\D\January1920\ Scan25 | |
| Date | 31th January 1920 | |
| To DA.{Bernard Day - Chassis Design} from E.{Mr Elliott - Chief Engineer} Copy to Cdr{W. J. Chandler - Chief Clerk} " HN.{F. C. Honeyman - Retail orders} " HS.{Lord Ernest Hives - Chair} " CK.{Mr Clark} X.3886 ORIGINAL. RE BRUSH HOLDER FOR STARTER MOTOR. 40/50 H.P. CHASSIS. On the 24th instant we sent to you drawing No. Lec.1193 shewing a design of brush holder which is an improvement on the model which you brought to us on your last visit. The following list of points indicates the chief modifications that have been made:- (1) The coil spring has been considerably increased in diameter, and lowered in rating. (2) The flat spring has been considerably stiffened up so that it will have approximately one-quarter of the deflection of the one fitted to the model. (3) The brush frame is of sheet metal on three sides for the purpose of making the base casting more simple. (4) The socket for the end of the toggle mechanism spring plunger is made as a separate piece, and of sufficient depth to prevent the toggle flying out on its extreme positions. (5) The angle of the slot in the yoke for carrying the spring pressure has been arranged so as to give maximum security for both extreme positions of the toggle. (6) The yoke, or portion carrying the flat spring finger has been made of thicker material, and the spring is now bolted to the inside surface, being cramped thereon by means of a XXXXXXX plate, and two set screws with hexagon heads, the latter being locked by a thin flat washer. (7) The pivot pin carrying the yoke has been increased in diameter. (8) The pressure on the brush has been arranged for 5 lbs per square inch for a new brush, and this pressure will drop very little as the brush wears, due to the low rating of the coil spring. E.{Mr Elliott - Chief Engineer} | ||