ASME B29.28:2015 pdf free download

ASME B29.28:2015 pdf free download High-Strength Chains for Power Transmission and Tension Linkages
1 sCOPE
This Standard covers roller chains that are specificallydesigned to withstand occasional high shock loads orhigh starting loads that are encountered in certain con-struction equipment and other severe-duty applications.WARNING:Chains covered in this Standard shall not be usedas the primary lifting member,or in the direct drive line ofelevators, escalators, or similar devices for lifting human passen-gers unless applied in accordance with ASME A17.1.Chainscovered in this Standard shall not be used as climbing chains.
2HIGH-STRENGTH ROLLER CHAINS
2.1 Nomenclature
high-strength roller chain: roller chain consisting of aseries of alternately assembled roller links [see Fig. 1,illustrations (a) and (b)] and pin links [see Fig. 1,illustration (c) and pint link] in which the pins articulateinside the bushings and the rollers are free to turn onthe bushings.The pins and bushings are press fit in theirrespective 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, andtwo pins F-E.
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 linkplate E, two cross-drilled pins G-G, and a detachablepin 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 toterminal fittings in a tension linkage [see Fig.1, illustra-tion (d)]. Some manufacturers may use a retention meansother than, but equivalent to, cotters.
NOTE:Offset links for high-strength roller chains are not coveredin this Standard.
2.2 General Proportions
The general proportions of high-strength roller chainsare the same as for heavy series chains listed inASME B29.1.
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.