ISO-8488-1986.pdf
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1、International Standard 8488 0 N 4 4! INTERNATIONAL ORGANIZATION FORSTANDARDIZATION.MEH(YHAPOHAR OPrAHH3AHR IlO CTAHAAPTM3AMWORGANlSATlON INTERNATIONALE DE NORMALISATION Cycles - Screw threads used to assemble head fittings on bicycle forks Cycles - Filetages utilis.Gs pour iassemblage des craccessoi
2、res) de direction sur les fourches de bicyclettes First edition - 1966-66-15 ii? UDC 629.116.3 : 621.662.662 i Ref. No. IS0 6466-1966 (E) 4 Descriptors : road vehicles, bicycles, forks, locknuts, screw threads, dimensions, dimensional tolerances, designation, s Price based on 6 pages Copyright Inter
3、national Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 21:22:11 MDTNo reproduction or networking permitted without license from IHS -,-,- Foreword IS0 (the International Organization for Standardizati
4、on) is a worldwide federation of national standards bodies (IS0 member bodiesj. The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be re
5、presented on that committee. International organizations, govern- mental 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 approval before their acceptance as International
6、Standards by the IS0 Council. They are approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting. International Standard IS0 8488 was prepared by Technical Committee ISO/TC 149, Cycles. Users should note that all International Standards undergo revision
7、from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. 0 international Organization for Standardization, 1986 0 Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under
8、 license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 21:22:11 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 9499-1996 (E) Cycles - Screw threads used to assemble head fittings on bicycle forks 0 Introductio
9、n Inch screw threads of BSC (British Standard Cycle) thread pro- file are used extensively throughout the world for various applications on bicycle components, and have been stan- dardized in national standards. The purpose of this document is to provide an International Standard for the particular
10、screw thread used to assemble the head race and locknut on bicycle forks; it is based on the use of the IS0 basic thread profile and complies as far as is practicable with existing International Standards for general purpose screw threads. The change to an IS0 system of screw threads will inevitably
11、 take a long time to complete in view of the millions of bicycles now in use which employ BSC thread profile inch screw threads and for which replacement spare parts will be required. For this reason, in order to minimize changes in production methods during the changeover to the International Stand
12、ard, and also to secure satisfactory interchangeability with the BSC screw threads now used, the IS0 screw thread in this Inter- national Standard has the same pitch as that of the I.000 in x 24 t.p.i. BSC screw thread it is intended to replace. An M25,522 x 1,055 (1.005 in x 24 t.p.i.1 screw thread
13、 of IS0 basic profile has been adopted in this International Standard. The basic pitch diameter of this thread is identical to the 1 .ooO in x 24 t.p.i. BSC thread, but, due to the smaller crest truncation of the IS0 profile (see figure 11, interference may occur at the major diameter when an IS0 fo
14、rk thread made towards its upper limit is assembled with a BSC race/locknut thread made towards its lower limit on major diameter. The possibility of interference occurring in this manner is con- sidered to be unlikely in practice because of the effect of the manufacturing tolerances ( -ve on the fo
15、rk and + ve on the fit- tings) and the usual practice of using high-crested screwing taps. However, a practical investigation has been carried out and has confirmed that there is little possibility of any in- terference arising in practice. NOTE - In addition to the 1.000 in x 24 t.p.i. BSC thread r
16、eferred to above, it should particularly be noted that there exists in the cycle trade other widely used threads: - French 25 mm x 1,0 mm (0.964 in x 25.4 t.p.i.) - Italian 25.4 mm x 1,056 mm (1 in x 24 t.p.i.1 - UK 25.4 mm x 0,977 mm (1 in x 26 t.p.i.1 - USA 25,4 mm x 1,059 mm (1 in x 24 t.p.i.1 Th
17、e French and UK threads are clearly not interchangeable with the BSC thread due to outside diameter and t.p.i. respectively. The Italian thread is also not compatible due to the Italian flank angle of 55O compared to the BSC angle of 50. As referred to in the second paragraph above, this IS0 system
18、of screw threads is intended to replace the 1.ooO in x 24 t.p.i. BSC threading, but the continued usage of the other non- compatible threadings is not in harmony with the objects of IS0 worldwide standardization, and wherever and as soon as possible, it is strongly recommended that all new products
19、change over to the new IS0 threads detailed herein. It should also be noted that where the design size of the fork column tube is already 25,4 mm (1 .tKlO in) nominal, the thread cutting of this new IS0 thread will increase the truncation and facilitate assembly. Attention should be paid to IS0 6692
20、 for the proposals on thread identification marking. 1 Scope and field of application This International Standard specifies details of the screw threads used to assemble head races and locknuts, i.e. fittings, on bicycle fork steering columns. The basic thread profile is that of IS0 58; the toleranc
21、e grades and tolerance positions are in accordance with IS0 965/l ; the gauging system is that specified in IS0 1502. Threads to this International Standard are interchangeable with the corresponding BSC (British Standard Cycle) thread. 2 References IS0 68, IS0 general purpose screw threads - Basic
22、profile. IS0 %5/l, IS0 general purpose metric screw threads - Tolerances - Part 1: Principles and basic data. IS0 1502, IS0 general purpose metric screw threads - Gauging. IS0 6692, Cycles - Marking of cycle components. Copyright International Organization for Standardization Provided by IHS under l
23、icense with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 21:22:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8488-1986 (El 3 Basic IS0 thread profile and basic sizes 3.1 Basic profile The basic profile is that given in IS0 68 and is
24、 shown in figure 1. It is the theoretical profile associated with the basic sizes of the major, pitch and minor diameters of the screw thread. 3.2 Basic sizes The basic major diameter, and the basic pitch and minor diameters determined from the basic profile, are given in table I. 4 Limits and toler
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