TSO NTERNATIONAL STANDARD 1971 Aircraft -- Accessory drives and mounting pads Aéronefs - Fixation et entrainement d'accessoires surmoteurs et boites-relais First edition -- 1975-03-15 ISO 1971-1975 (E) UDC 629.7.03-233 Ref. No. ISO 1971-1975 (E) Descriptors : aircraft equipment, aircraft engines, gearboxes, accessories, couplings, quick-release fasteners Price based on 17 pages Copyright International Organization for Standardization ted without license from IHS Not for Resale FOREWORD ISO (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approvat before their acceptance as International Standards by the IsO Council. International Standard Iso 1971 was drawn up by Technical Committee ISO/TC 20, Aircraft and space vehicles, and circulated to the Member Bodies in March 1970. Belgium India Spain Brazil Israel Switzerland Italy Thailand Canada Egypt, Arab Rep. of Japan Turkey France Netherlands United Kingdom Germany New Zealand Greece South Africa, Rep. of The Member Bodies of the following countries expressed disapproval of the document on technical grounds : Czechoslovakia U.S.A. U.S.S.R. @ International Organization for Standardization, 1975 : Printed in Switzerland CoyrightInteationalrganizatonforStandardizatio Not for Resale sefromIHS ISO 1971-1975 (E) INTERNATIONAL STANDARD Aircraft -- Accessory drives and mounting pads 1 SCOPE AND FIELD OF APPLICATION 2 REFERENCES IsO 48, Vulcanized rubbers - Determination of hardness. 1.1 This International Standard provides a design for ISO/R 468, Surface roughness. quick-release couplings with invofute spline drive, intended ISO/R 1078, Dimensions of elastomeric toroidal sealing primarily for aircraft engine/gearbox accessories which rings for aircraft (Inch series - Class 1 tolerances). require to be removed whilst the engine/gearbox is in service. 3 REQUIREMENTS FOR ASSEMBLY SEQUENCE 1.2 This International Standard comprises 3.1 The engine/gearbox pads and accessory flanges shal! be clauses 3 to 12 : Design notes and recommendations; dimensioned so that the locating pin (or transfer tube) is engaged in its mating hole before the interference on the figure 1/tables 1a) to 1e) : Accessory flanges up to spigot sealing rings prevents rotation of the accessory spigot reference 250; casing. figure 2/tables 2a) to 2d) : Engine/gearbox pads up to spigot reference 250; 3.2 in fixing the protrusion of the drive shaft, consideration shall be given to engaging the spline before figure 3/tables 3a) to 3e) : Accessory flanges above the locating pin (or transfer tube) is engaged, in order to spigot reference 250; ease assembly. figure 4/tables 4a) to 4e) : Engine/gearbox pads 3.3 In the case of heavy accessories, the design shall above spigot reference 250; preclude the fitter allowing the weight of the unit to hang on the splines rather than on the spigot. This can usually be - figure 5/tables 5a) and 5b) : Coupling clamps; arranged by keeping the amount of spline engagement to a minimum before the spigot is engaged. figure 6/tables 6a) and 6b): Selected involute splines. 3.4 The quill shaft shall be as long as practicable in relation to the length of the splines, to reduce the effect of 1.3 Items subject to agreement between engine/gearbox out-of-alignment due to manufacturing tolerances. Unless otherwise agreed, the engine/gearbox manufacturer shall be manufacturer and accessory manufacturer are listed in an responsible for design and supply. annex. Copyright Inte