Modifications for the 40/50 HP chassis switchbox before standardization.
| Identifier | WestWitteringFiles\D\November1919\ Scan20 | |
| Date | 24th November 1919 | |
| To DA. {Bernard Day - Chassis Design} from E. {Mr Elliott - Chief Engineer} Copy to C.J. " " BN. {W.O. Bentley / Mr Barrington} " " EH. " " EFC. {E. Fowler Clarke - Electrical Engineer} ORIGINAL X.3618 E1/G22/11/19. RE SWITCHBOX MODIFICATIONS - LEC.1161. We send you herewith drawing No. as above, dealing with the alterations to the 40/50 H.P. chassis switchbox, which should be made before this piece is standardised. Mr. Royce is very pleased with the model switchbox which you sent to Wittering, but thinks that the following modifications must be made before standardisation is attempted, the chief point of alteration being that relating to the springs and plungers, and to the cam forms. The points requiring attention are as follows:- (1) Spring plungers and springs increased in diameter. Load of springs reduced, compared with the model supplied, and rating made very low. No features for stops on plungers. (2) Cam form on plunger spindles altered so as to give a decreasing resistance to the pressure of the fingers and ensure a quick break on the switch. The spindle ends chamferred for ease of erection, and spindles made in low carbon steel, case hardened on cam portions only. (3) Bridge piece carried further back and altered in shape so as to allow more room for conductors. Conductors of .240" diameter (measured from sample supplied) accommodated, but expect that smaller than this will be used. (4) Casing altered in shape so as to more closely follow the profile of the parts to be covered, and thus be less bulky. The alteration covers the increased amount of room required for the larger cables. (5) Switch blades altered and heads of securing bolts made smaller so as to have a more prominent curved feature on the contact end, and more clearance with the sliding element. Blades should no longer be soldered to bolt heads. Contact pieces on sliding element should be in silicon bronze to avoid excessive wear. (Contd.) | ||
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).