ASME B29.100-2002 pdf download
ASME B29.100-2002 pdf download.PRECISION POWER TRANSMISSION,DOUBLE PITCH POWER TRAINSMISSI0N,AND DOUBLE PITCH CONVEYOR ROLLER CHAINS, ATTACHMENTS,AND SPROCKETS.
A1.1.1 General. The horsepower ratings in Tables A4 through A17 generally apply to lubricated single-pitch, single-strand roller chains, both American National standard and heavy series. For horsepower ratings of multiple strand chains, refer to Table A2. The horsepower ratings reflect a service factor of 1, a chain length of approximately 100 pitches, use of interference-fit connecting links, use of recommended lubrication methods, and a drive arrangement where two aligned sprockets are mounted on parallel shafts in a horizontal plane. Under these conditions, approximately 15,000 hr of service life at full load operation may generally be expected.
Substantial increases in rated speed loads can be utilized, as when a service life of less than 15,000 hr is satisfactory, or when full load operation is encountered only during a portion of the required service life.
It is beyond the scope of this publication to present selection procedures for all conditions. Consult chain manufacturers for assistance with ally special application requirements.
A1.1.2 Drive Selection. The horsepower ratings relate to the speed of the smaller sprocket and drive selections are made on this basis, whether the drive is speed reducing or speed increasing.
Drives with more than two sprockets, idlers, composite duty cycles, or other unusual conditions often require special consideration. It is advisable to consult chain manufacturers for selections of this nature.
Where quietness or extra smooth operation are of special importance, a small pitch chain operating over large diameter sprockets will minimize noise and vibration.
When making drive selections, consideration is given to the loads imposed on the chain by the type of input power and the type of equipment to be driven. Service factors are used to compensate for these loads, and the required horsepower rating of the chain is determined by the following equation:
The oil should be directed at the slack strand, and applied inside the chain loop and evenly across the chain width.
Consult chain manufacturers when it appears desirable to use a type of lubrication other than that recommended.
A1.5 Sprockets
Sprockets should have tooth form, thickness, profile, and diameters conforming to this Standard. For maximum service life, small sprockets operating at moderate to high speeds, or near the rated horsepower, should have hardened teeth. Normally, large sprockets should not exceed 120 teeth.
A1.6 Center Distance
In general, a center distance of 30 to 50 chain pitches is most desirable. The distance between the sprocket centers should provide at least 120 deg chain wrap on the smaller sprocket.
Drives may be installed with either adjustable or fixed center distances. Adjustable centers simplify the control of chain slack.
For drives on fixed centers, an idler or shoe may be used to provide slack adjustment. These devices may also be used to control backlash, or to assure 120 deg minimum chain wrap on the smaller sprocket. Sufficient housing clearance must alzvays be provided for the slack chain to obtain full chain life.
A1.7 Alignment
Accurate alignment of shafts and sprocket tooth faces provides uniform distribution of the load across the entire chain width and contributes substantially to optimum drive life. Shafting, bearings, and foundations should be suitable to maintain the initial alignment. Periodic maintenance should include an inspection of alignment to insure optimum chain life.
A1.8 Horsepower Ratings Tables
To properly use the horsepower ratings (Tables A4 through A17), the following factors must be taken into consideration:
(a) service factors of Table Al;
(b) multiple strand factors of Table A2;
(c) lubrication. The horsepower established from the sprocket and speed combination of the drive under consideration will indicate a method of lubrication. This method or a better one must be used to obtain optimum chain life.
NOTE: The horsepower ratings permit the use of interference-fit connecting links. Chains using interference-fit offset sections or slip-fit connecting links may not meet these ratings. Chains using slip-fit offset links will not meet these ratings. Consult the chain manufacturer for specific derating factors for their slip-fit connecting links, offset sections, or offset links.
