GB/T 1243-2024Short-pitch transmission precision roller and bush chains, attachments and associated chain sprockets (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020

"Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents".

This document replaces GB/T 1243-2006 "Short-pitch transmission precision roller and

bush chains, attachments and associated chain sprockets". Compared with GB/T 1243-

2006, in addition to structural adjustments and editorial changes, the main technical

changes are as follows.

- CHANGE the ISO chain number of the A series chain in GB/T 1243-2006 from

"04C, 06C, 08A, 085, 10A, 12A, 16A, 20A, 24A, 28A, 32A, 36A, 40A, 48A" to

the chain number "25, 35, 40, 41, 50, 60, 80, 100, 120, 140, 160, 180, 200, 240",

which is consistent with the ANSI series chain (see Table 1; Table 1 of the 2006

edition);

- CHANGE the footnote a of Figure 3b) from "Chain channel height (h1) is the

rotational clearance between the transition link plate and the straight link plate at

the connection" to "Chain channel height (h1) is the minimum channel height that

allows the assembled chain to pass through" [see Figure 3b; Figure 3b of the 2006

edition];

- CHANGE that "Chains manufactured in accordance with this standard shall be pre-

tensioned; the applied pre-tension load shall be equal to 30% of the minimum

tensile strength value specified in Tables 1 and 2" into that "Chains manufactured

in accordance with this document shall be pre-tensioned; the applied pre-tension

load shall not be less than 30% of the minimum tensile strength value specified in

Tables 1 and 2" (see 3.4.3; 3.4.3 of the 2006 edition);

- ADD the ANSI extra heavy series (HE series) chains (see Table 2).

This document is equivalent to ISO 606.2015 "Short-pitch transmission precision roller

and bush chains, attachments and associated chain sprockets".

Please note that some contents of this document may involve patents. The issuing

agency of this document does not assume the responsibility for identifying patents.

This document was proposed by the China Machinery Industry Federation.

This document shall be under the jurisdiction of the National Chain Transmission

Standardization Technical Committee (SAC/TC 164).

Drafting organizations of this document. Chain Transmission Research Institute of Jilin

University, Hangzhou Donghua Chain Group Co., Ltd., Zhejiang Hengjiu Transmission

Technology Co., Ltd., Jiangsu Shuangling Chain Transmission Co., Ltd., Zhejiang

Short-pitch transmission precision roller and bush chains,

attachments and associated chain sprockets

1 Scope

This document specifies the technical requirements for short pitch precision roller and

bush chains and sprockets, which are suitable for mechanical transmission and similar

applications, including dimensions, tolerances, length measurements, pre-tensioning,

minimum tensile strength, minimum dynamic load strength.

Although Chapter 5 applies to sprockets for bicycles and motorcycles, this document

does not apply to bicycle and motorcycle chains, which are specified in ISO 9633 and

ISO 10190, respectively.

2 Normative references

The contents of the following documents constitute essential provisions of this

document through normative references in the text. Among them, for referenced

documents with dates, only the version corresponding to that date applies to this

document; for referenced documents without dates, the latest version (including all

amendments) applies to this document.

ISO 286-2 Geometrical product specifications (GPS) - ISO code system for

tolerance on linear sizes - Part 2.Tables of standard tolerance classes and limit

deviations for holes and shafts

Note. GB/T 1800.2-2020 Geometrical product specifications (GPS) - ISO code system for

tolerances on linear sizes - Part 2.Tables of standard tolerance classes and limit deviations

for holes and shafts (ISO 286-2.2010, MOD)

ISO 15654 Fatigue test method for transmission precision roller chains and leaf

chains

3 Chains