ASME B29.2M-2007 df – Inverted Tooth (Silent) Chains and Sprockets.
(a) Silent chain is a series of toothed links alternately assembled with pins or a combination of joint components in such a way that the point articulates between adjoining pitches. As shown in Fig. I, illustration (a), side guide silent chain has guide links which %traddle the sprocket sides to control the chain laterally As shown in Fig. 1. illustration (b). center guide silent chain has guide links which run within a circumferential groove or grorwes for lateral control.
(1’) Typical Links. Since joint components. connectors, and offset sections vary with each manufacturer, these items are not included in this Standard. See Fig. 2 for examples of typical links,
1.2 General Configuration
Link contour may vary but must engage standard sprocket teeth so that joint centers lie on sprocket pitch circle.
(a) in. Pitch Chant and Litrgei Chain widths equal to, or exceeding, two times the pitch have center guides. Narrower chain.s may be side guide or center guide. Chain widthsexceeding 16 times the pitch are not recommended.
(b) , in. Pitch Chain. Chain may be side guide or center guide as indicated in para. 1.8.
(C) Maximum Chain Width. Maximum chain width should be limited to approximately eight times the pitch.
1.3 NumberIng System
(a) in. Pitch Chain and Lurs’r. Two lettet (SC) as a prefix, one or two numerals indicating pitch in eighths of an inch, and two or three numerals indicating nominal chain width in quarters of an inch. Thus, SC302 designates a silent chain, in. pitch by in. nominal width, and 5C1012 designates a silent chain, l!’ in. pitch by 3 in. nominal width.
(h.t 3 in. Pitch Chain. Two letters (SC) as a prefix, a zero Iollowed by a numeral indicating pitch in sixteenths of an inch. and two numerals indicating nominal width of chain in thirty-seconds of an inch. Thus, 5C0309 designatesa silent chain, in. pitch by in. nominal width.
NOTE: Where hnks are all ol equal thlcknew 0.03 In. (0.76 mm). Ills undamkxsi that the width Indication abode,ignates the total number of linL,. acns the width cit the chain.
1.4 Tolerance for Chain Length
(a) ‘4 in. Pitch Chain and Largr. Chains will be designed and manufactured to fit gage sprockets. Tolerance for chain length for new chains may be over nominal length 0.03 in/It (0,76 mm/n) but must not bc underlength.
(I) in. Pstd Chain. Chain length tolerance is 002 ui/ft (0.51 mm/rn) over nominal length but must not be underlength.
1.5 Measuring Loads
(a) Y in. Pitch Chair, and rijcr. Chain should be measured under load of 25 lb x pitch in inches x width in indies + 20 lb (0.1724 N x pitch in mm x width in mm + 89 N). I.engdi nwasurements are to be taken over a length of at least 12 in. (300 mm).
(b) in. Pitch Clwiri. The measuring load for in. pitch silent chain shall be approsimately equal to 1 lb (44S N) for each link in the total chain width, i.e., the load for SC0315 would be 15 lb (67 N). Length measurements are to be taken over a length of at least 12 in. (300 mm).
1.6 General Chain Dimensions for % in. Pitch Chain and Larger
See Fig. 3 and Tables I and 2.
1.7 ChaIn Widths and Sprocket Face Profiles for
% in. Pitch Chain and Larger
See Fig. 4 and Tables 3 and 4.
1.8 Chain Widths and Sprocket Face Profile for In. Pitch Chain
See Fig. S and Tables 5 and 6.
2.1 Tooth Form Dimensions for % In. Pitch Chain and Larger
See Fig. 6.
2.2 Tooth Form Dimensions for ‘/ in. Pitch Chain See Fig. 7.