(This Foreword is not part of ASME B29.11M-1994.)
In 1886 a patent was granted for a chain comprised of cast metal block links, fitted with bronze bushings, and connected with wrought steel sidebars and removable pins. This chain was the forerunner of the present combination chain, later placed on the market around 1900. Many sizes and types of combination chains were developed and marketed in the next several years.
During World War I, the War Industries Board insisted that chain manufacture be confined to the necessary sizes. This caused elimination of several types and sizes, and planted the seed for future standardization. Following World War I, the Malleable Chain Manufacturers Institute was formed, and this group did considerable work on standardization of chain and sprocket dimensions for combination chains of the more popular sizes. There were still dimensional variations that would not permit universal intercoupling of chains of different manufacture, necessitating repairs made with chains of the original manufacturer.
The ASCMA (now the American Chain Association), recognizing the need for a complete standard providing intercoupling and direct replacement of chains of diferent manufacture, established this Standard utilizing the minimum number of chains to meet requirements of industry for the chains widely used in conveyor and elevator applications.
To facilitate the use of this Standard in the international market, the metric equivalents of all dimensions are given.
This Standard was presented to the USASI (now the American National Standards Institute) B29 Committee in December 1963 and, upon approval by the USASI on May 24, 1968, was adopted and published.
The 1974 revision included minor changes in metric units and change from ultimate strengths to proof test loads with the corresponding explanatory and caution notes.
The American National Standards Institute approved the previous revision in 1984.
The 1994 revision defines the proof test loads as "minimum" in Table 1 and adds minimum attachment hole diameters to Tables 4 through 9. The information in Fig. 4 was modified to strengthen the recommendation for undersized root diameters and pocket radii.
The American National Standards Institute Approved the current revision on November 14, 1994.