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).
Requirements and specifications for single and two-tone Klaxon buzzer type horns for different chassis.
Identifier | ExFiles\Box 59\3\ Scan095 | |
Date | 8th December 1930 | |
Sg.{Arthur F. Sidgreaves - MD} from EFC. c. R.{Sir Henry Royce} Wor.{Arthur Wormald - General Works Manager} c. Ey. Hs.{Lord Ernest Hives - Chair} c. C. Cx{Major Len W. Cox - Advertising Manager}/Hdy.{William Hardy} c. Da{Bernard Day - Chassis Design}/Ev.{Ivan Evernden - coachwork} X6074 X6074/5. X.1163b/c. EFC3/AD8.12.30. SINGLE AND TWO-TONE KLAXON BUZZER TYPE HORN. Horn requirements for our two chassis as arrived at by Da{Bernard Day - Chassis Design}/EV{Ivan Evernden - coachwork}7/M27.11.30, Cx{Major Len W. Cox - Advertising Manager}/Hdy{William Hardy}12/LP{Mr Lappin}1.12.30 and Da{Bernard Day - Chassis Design}/Ev{Ivan Evernden - coachwork}2/M4.12.30 appear to be that for the Phantom II we require the combination of the deep noted Cobra horn with the high single tone buzzer type (Klaxon) horn similar to the Bosch, and that for the 20/25 we require a two-tone buzzer type (Klaxon) horn giving as near an approach as possible, in effect, to the Phantom II arrangement. It is further suggested that considerable saving would accrue if the two-tone horn could be sufficiently well developed in the direction above referred to, and utilised on Phantom II. In this connection a few words of explanation regarding the notes and tones of such horns appear to be necessary. It is the case that the note, as distinct from the tone, of all these buzzer type horns is approximately the same frequency i.e. ranging about the of frequency of 300 t 20. Itwill be understood that this refers to the fundamental of the horn which determines its "note". It should be further explained that this is the result of the mechanical dimensions and masses of the vibrating system comprising diaphragm and armature connected thereto being approximately the same from horn to horn in those we have tried, it being remembered that both the Klaxon and the Lucas are more or less a copy of the Bosch. None of these horns incorporate the striker type of action. Our remarks also apply to the two-different "tones" of the same horn which differ but little in note. Considerable differences in the amount of noise (amplitude of vibration) occur and also considerable differences of tone arising from differences in the harmonics accompanying the fundamental. In the two-tone horns which we have tried, the most noticeable difference is, as would be expected for use in towns, that of amplitude. It is true that the lower tone is slightly lower in frequency and at | ||