scope:

The B29 Standards Committee agreed to propose a draft standard to consolidate and revise the following three chain standards: ASME B29.1M, Precision Power Transmission Roller Chains, Attachments, and Sprockets; ASME B29.3M, Double-Pitch Power Transmission Roller Chains and Sprockets; and ASME B29.4M, Double-Pitch Conveyor Roller Chains, Attachments, and Sprockets. The new standard was designated ASME B29.100-2002 and was approved as an American National Standard on April 3, 2002.

B29.1. The original design of precision roller chain dates back to the late 1890s, although various types of drive chains have been in use for centuries. The early automobiles used roller chain extensively as the final drive. The industrial use for roller chain grew substantially, resulting in the desirability of standardization. The perfected American Standard Chain of today has evolved to meet the demand for ever-increasing horsepower and higher speeds, as well as accurate timing.

In 1913 the Society of Automotive Engineers published formulas for calculating the roller chain length, sprocket tooth profiles, and other important design criteria. Recommendations from the Roller Chain Committee of the American Society of Mechanical Engineers followed in 1917 with dimensional standards for the various components and assemblies. Early in 1920, through the cooperation of these two groups, roller chain standards were formulated and recommended for acceptance by industry. The progress was followed in 1921 by organization of a sprocket committee of the American Gear Manufacturers Association.

ASA Sectional Committee B29, Transmission Chain, Sprockets, and Cutters, was organized in 1924 by the American Standards Association with ASME, AGMA, and SAE as sponsors. A subcommittee on roller chain was established to study modern practices of roller chain manufacture and use. Its recommendations on standards were approved by the Sectional Committee in May 1929 and approved by the American Standards Association in July 1930. They were published as B29a-1930, Roller Chain, Sprockets, and Cutters. This roller chain standard assured interchangeability and optional sources of supply.

In 1930 the Association of Roller and Silent Chain Manufacturers (ARSCM) was founded. The objectives of the association were to cooperate in developing standards of sound engineering and manufacturing practice, to foster improvements in chain performance, and to extend the use of roller chain. This association was subsequently dissolved in 1960 and its members became part of the American Sprocket Chain Manufacturers Association (ASCMA), which was organized to bring together manufacturers of all types of sprocket-driven chain. The name of this group was changed in 1971 to American Chain Association.

As a result of combined industry research programs sponsored by ARSCM, starting in 1946 and continuing under ASCMA, greater predictability of roller chain drive service life has been achieved. These studies provided greater knowledge of such roller chain characteristics as link plate endurance strengths, roller impact forces, dynamic tension forces, operating efficiency, wear life of well-lubricated drives at various speeds and loads, pin-bushing interaction at high speeds, and the phenomenon of chain joint galling. This scientific exploration produced such vast gains in the technical knowledge of capabilities of roller chain that increases in horsepower ratings were possible. The wear studies, for example, have shown that a separating film of lubricant is formed in chain joints in a manner similar to that found in journal bearings. These studies thus opened a region of chain application at high speeds which had previously been thought to be impractical. The direct result of this research has been the continual increase in chain horsepower ratings contained in Nonmandatory Appendix A. The Appendix also contains suggestions concerning the application and use of the chains covered by this Standard.

This Standard covers transmission roller chains, attachments, and sprockets. It is intended to facilitate fulfillment of the needs of users, distributors, and manufacturers of chain sprocket drives on a sound economic basis and in a manner consistent with sound engineering and manufacturing practices.

Control dimensions are given in this Standard to assure interchangeability between chains, sprockets, and chain links as supplied by different manufacturers. Information for the guidance of users in the application of these drives is also included.

In addition to its customary usage as a power transmission medium, precision roller chain has also been adapted for use in conveying, elevating, indexing, and timing operations. Modifications of standard chain parts to perform these functions are known as attachments. To assure interchangeability of the more commonly used attachments, standardization of certain principal dimensions was initiated in 1947. This information, formerly published as a separate standard, was incorporated into this precision roller chain standard.

In tabulating dimensional information in this Standard, customary inch-pound units have been used. Additionally, companion tabulations have been included in order to provide translations of these values into metric (SI) units in accordance with ASME Guide SI-1, ASME Orientation and Guide for Use of SI (Metric) Units. For this reason, certain formulas and relationships have been intentionally presented only in customary units so as to preclude any ambiguity between them and the tabulated values.

ASME/ANSI B29.1M-1986 was approved by the American National Standards Institute on January 9, 1986.

ASME B29.1M-1993 included two significant modifications. The first was a revision to the definition of minimum ultimate tensile strength that clarified the meaning and use of the term. The second was a revision to the listed values for maximum pin diameter and minimum hole in bushing. These changes do not affect the interchangeability of the chains. The values were changed to provide a rational basis for conversion between conventional (inch) and SI (metric) dimensions. With concurrent changes in the related ISO standards, a long-standing area of potential discrepancies is eliminated. ASME B29.1M-1993 was approved by the American National Standards Institute on August 10, 1993.

ASME B29.100-2002 includes four significant modifications to B29.1: a revision to the minimum ultimate tensile strength definition, the addition of minimum dynamic strength and conformance test requirements for chains specified in this Standard, the addition of requirements for roller chain preloading, and a revision to the note in para. A1.8. The revision recognizes the need for the user to contact the roller chain manufacturer for specific derating factors for slip-fit connecting links, offset sections, and offset links. Similar changes are being made to International Standard ISO 606 to be in close agreement with this Standard.

B29.3. For many years, roller chain manufacturers furnished for specific installations an economical power transmission chain differing only in pitch from the standardized series of transmission roller chains which conformed to American Standard ASA B29.1.

Such practice became so common and the chains of such universal use that in 1948 the Roller Chain Technical Committee of the Association of Roller and Silent Chain Manufacturers, now known as the American Chain Association, developed standards which were submitted for adoption as an American Standard.

This Standard describes a limited series of double-pitch power transmission roller chains which supplements the base chain series conforming to the standard B29.1. These chains differ from the base chains only in pitch, which is double that of the corresponding base chain.

Supplementary information in Appendix A on speed and power transmission ratings indicates their special usefulness for drives operating at slow to moderate speeds, with moderate loads and long center distances.

In tabulating dimensional information in this Standard, customary inch-pound units have been used. Additionally, companion tabulations have been included in order to provide translations of these values into metric (SI) units in accordance with ASME Guide SI-1, ASME Orientation and Guide for Use of SI (Metric) Units. For this reason, certain formulas and relationships have been intentionally presented only in customary units so as to preclude any ambiguity between them and the tabulated values.

ASME B29.3M-1994 incorporated a restatement of the definition of minimum ultimate tensile strength, and minor changes in the values for maximum pin diameter and minimum bushing inner diameter. The dimensional changes were to allow a direct error-free conversion from customary inch units to metric (SI) units. Similar changes were made in the International Standard ISO 1275. ASME B29.3M-1994 was approved by the American National Standards Institute on March 15, 1994.

ASME B29.100-2002 includes three significant modifications to B29.3: a revision to the minimum ultimate tensile strength definition, the addition of the requirements for roller chain preloading, and the removal of some sprocket data that is identical to B29.1. The sprocket information sections have been revised to reference the appropriate sections of B29.1 sprocket data.

B29.4. For many years, roller chain manufacturers have furnished a substantial volume of precision steel roller chains and sprockets of a limited series for specific conveying applications. Such chains consist of pins and bushings identical to American National Standard B29.1 transmission roller chains; rollers identical to or, alternatively, approximately twice as large in diameter as those of such transmission roller chains; and link plates with straight-edged contours, extended in pitch to be double the pitch of those of the corresponding transmission roller chains conforming to the latest edition of B29.1. (Such chains are referred to in this Standard as base series chains.)

These double-pitch steel conveyor chains have frequently been assembled with some parts of modified design to adapt the chains for use in conveying, elevating, or timing operations. The parts most commonly modified are pin link plates, roller link plates, and pins.

Previously, variation in link plate thickness, attachment link plate hole size and location, diameter and length of extension pins, and sprocket details caused lack of interchangeability and tended to restrict users to one source of supply. For these reasons, the Association of Roller and Silent Chain Manufacturers began to develop a standard in 1947. It was approved as an American National Standard on May 30, 1972, and supplemented B29.1.

In tabulating dimensional information in the present revision, customary inch-pound units have been used. Additionally, companion tabulations have been included that are metric (SI) conversions of these units in accordance with ASME Guide SI-1, ASME Orientation and Guide for Use of SI (Metric) Units. Certain formulas and relationships have been intentionally presented only in customary units to preclude any ambiguity between them and the tabulated values.

Nonmandatory Appendix A includes suggestions on application and use of chains covered by this Standard. The information on conveyor capacity ratings indicates the special usefulness of these chains and attachment links for slow-speed conveyor applications.

ASME B29.4M-1994, which was approved by the American National Standards Institute on March 15, 1994, incorporated a restatement of the definition of minimum ultimate tensile strength, and minor changes in the values for maximum pitch diameter and minimum bushing inner diameter. The dimensional changes are to allow a direct error-free conversion from customary inch units to metric (SI) units. Similar changes were made in the International Standard ISO 1275.

ASME B29.100-2002 includes three significant modifications to B29.4: a revision to the minimum ultimate tensile strength definition, the addition that roller chains conforming to this Standard should be preloaded at the discretion of the manufacturer or by agreement between the manufacturer and the user, and the removal of some sprocket data that is identical to B29.1. The sprocket information sections have been revised to reference the appropriate sections of B29.1 sprocket data.