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ASME B29.28-2015 pdf download

ASME B29.28-2015 pdf download.High-Strength Chains for Power Transmission and Tension Linkages.
1 SCOPE This Standard covers roller chains that are specifically designed to withstand occasional high shock loads or high starting loads that are encountered in certain con- struction equipment and other severe-duty applications. WARNING: Chains covered in this Standard shall not be used as the primary lifting member, or in the direct drive line of elevators, escalators, or similar devices for lifting human passen- gers unless applied in accordance with ASME A17.1. Chains covered in this Standard shall not be used as climbing chains. 2 HIGH-STRENGTH ROLLER CHAINS 2.1 Nomenclature high-strength roller chain: roller chain consisting of a series of alternately assembled roller links [see Fig. 1, illustrations (a) and (b)] and pin links [see Fig. 1, illustration (c) and pin link] in which the pins articulate inside the bushings and the rollers are free to turn on the bushings. The pins and bushings are press fit in their respective link plates. roller link: link consisting of two roller link plates A–A, two bushings B–B, and two rollers C–C. pin link: link consisting of two pin link plates E–E, and two pins F–F. NOTES: (1) Only heavy series high-strength roller chains are covered in this Standard. (2) Multiple-strand high-strength roller chains are not covered in this Standard. cotter-type connecting link: link consisting of a pin link plate E, two cross-drilled pins G–G, and a detachable pin link plate D, retained by two cotters H–H. Cotter- type connecting links are used to connect the chain end- less on a drive, or to connect the ends of the chain to terminal fittings in a tension linkage [see Fig. 1, illustra- tion(d)]. Some manufacturers mayusea retentionmeans other than, but equivalent to, cotters. NOTE: Offset links for high-strength roller chains are not covered in this Standard. 2.2 General Proportions The general proportions of high-strength roller chains are the same as for heavy series chains listed in ASME B29.1. 1 2.3 Numbering System For chains covered in this Standard, the right-hand digit in the number is a zero. The numbers to the left of the right-hand digit denote the number of eighths- of-an-inch in the chain pitch. The letters following the chain number shall be “HE,” with the letter “H” denot- ing heavy series and the letter “E” denoting high-tensile strength. 2.4 Chain Strength Requirements 2.4.1 Minimum Ultimate Tensile Strength. The mini- mum ultimate tensile strength (M.U.T.S.) for chains cov- ered in this Standard is the minimum force at which an unused, undamaged chain could fail when subjected to a single tensile loading test. WARNING: The M.U.T.S. is NOTa working load! The M.U.T.S. greatly exceeds the maximum force that may be applied to the chain in service. (a) Test Specimen. A length of chain, containing not less than five free pitches, shall be submitted for testing. (b) Test Procedure. A tensile force shall be applied slowly, not to exceed 2.0 in./min (50.8 mm/min), in a uniaxial direction, to the ends of the test specimen. (c) Conformance. Chains conforming to this Standard shall have a M.U.T.S. equal to or greater than the value listed for that specific chain listed in Table 1 or 1M. WARNING: The tensile test is a destructive test! Even though the chain might not visibly fail when subjected to the minimum ultimate tensile force, it will have been damaged and will be unfit for service. 2.4.2 Minimum Dynamic Strength. Only high- strength chains are subject to the minimum dynamic strength requirement; connecting links are not. WARNING: The dynamic test values are not valid characteris- tics for designing actual applications. Neither the specified val- ues nor the test results are to be interpreted as allowable working loads. (a) Test Procedure. The chain shall be tested according to the conformance test described in ASME B29.26. (b) Conformance. Chains covered in this Standard shall survive a conformance test at load listed for the subject chain in Table 1 or 1M. WARNING: The dynamic test is a destructive test! Even though the chain might have survived the test without failure, it will have been damaged and will be unfit for service.

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