Blending profiles of disc cams with radial translating roller followers. Part 2: to incorporate an intermediate precision point or a constant velocity component.
ESDU 93002 uses a method by which each motion segment (rise or return) is formed by blending together components of two single-law segments at the point of maximum follower velocity. A hand calculation method may be used@ based on the graphs of ESDU 92005 relating to six commonly-used cam laws@ or Fortran programs (ESDUpac A9302 for the precision point and ESDUpac B9302 for the constant velocity component)@ and both techniques yield the minimum allowable size of cam (based on the requirements that the maximum pressure angle does not exceed a specified value and that profile undercutting is avoided). The programs also use the six common cam laws but a user-specified law may also be input provided the maximum velocity occurs at the mid-point of a single segment. The output from the programs can if required include the follower motion at 1 degree intervals for a full cam rotation (displacement@ velocity@ acceleration and jerk). The theoretical background to the method is explained@ step-by-step design procedures are detailed@ and guidance on the use of the programs is given. A full description of the input and output formats is illustrated by practical worked examples. The programs are provided on disc (uncompiled) in the software volume and also compiled within ESDUview@ a user-friendly shell running under MS DOS that prompts on-screen for input data. ESDU 83027 also provides a hand calculation method for blending that applies to both translating and swinging arm followers but provides no information on minimum cam size.