ASME B29.100-2002 pdf free download.Precision Power Transmission,Double-Pitch Power Transmission, and Double-Pitch Conveyor Roller Chains,Attachments, and Sprockets.
Inc rour prtncipai rypvs or spmceis aiv aesignarcu in Fig. 4.
3.2 Classes of Sprockets
This Standard provides for two classes of sprockets. commercial and precision. Use of commercial or precision sprockets is a matter of drive application judgment. The usual moderate-to-slow speed commercial drive is adequately served by commercial sprockets. Where extreme high speed in combination with high load is involved, or where the drive involves fixed centers, critical timing or register problems, or close clearance with outside interference, then the use of precision sprockets may be more appropriate.
As a general guide, drives requiring Type A or Type B lubrication would be served by commercial sprockets. Drives requiring Type C lubrication may require precision sprockets, although even here commercial may be satisfactory Consult the manufacturer. Types of lubrication are shown in the horsepower ratings tables (Tables A4 through A17) provided in Nonmandatory Appendix A.
3.3 Tooth Section Profile
The tooth section profile, Sections A and 13 of Tables 7A and 7B, shows the recommended chamfering of sprocket teeth for roller chains. All sprocket flanges are to be chamfered to provide guidance of the chain onto the sprocket in case of misalignment due to sprocket misalignment or permissible flange weave. Flange chamfer may be as in Section A or B, or anything in between. The sprocket chamfer diniensions R, g, and 1. are noncritical and are given only as a guide for general design proport ions.
3.4 Sprocket flange Location and Thickness
See Fig. 5 and Tables SA, 86, SC, SD, 9A, and 96.
3.5 Tooth Form Dimensions
The tooth form shown in Fig. 6 is a theoretical form for the specific number of teeth N and is designed so that the chain, as it wears and elongates, will ride out toward the tips of the teeth. Because of the variety of ways to produce sprockrt teeth, the actual teeth may not exactly match the theoretical form. In the case of space cutters or milling cutters, it is common practice to design cutters to cut a form for an intemied late number of teeth for one of five ranges. This results in the cutter, the sprocket. and the theoretical form matching only at 56 teeth. In the case of hobs or shapers, the generated sprocket tooth form comes very close to thetheoretical form for all numbers of teeth,but actuallymatches only where and if the cutting tool design isbased on a specific whole number of teeth. Cast, powdermetal, or plastic molded teeth may or may not matchthe theoretical form, depending on how their pattern,die,or mold was designed and formed. All of theseforms have proved to be acceptable in service.Theimportant thing is that the seating curve diameter, bot-tom diameter, flange width, and chordal pitch be suchas to accept the meshing chain without wedging or bind-ing, so as to minimize chain loading and impact.(Foradditional information on cutting tools,see Nonmanda-tory Appendix A.)
3.6 Seating Curve Dimensions and TolerancesSee Tables 10A and 10B.
(a)Type A – Manual or Drip Lubrication
(1) For manual lubrication, oil is applied copiouslywith a brush or spout can at least once every 8 hr ofoperation. Volume and frequency should be sufficientto prevent overheating of the chain or discoloration inthe chain joints.
(2) For drip lubrication, oil drops are directedbetween the link plate edges from a drip lubricator.Volume and frequency should be sufficient to preventdiscoloration of lubricant in the chain joints. Precautionmust be taken against misdirection of the drops bywindage.
(b) Type B —— Bath or Disc Lubricatior
(1) For bath lubrication, the lower strand of chainruns through a sump of oil in the drive housing. Theoil level should reach the pitch line of the chain at itslowest point while operating.