From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
List of calculations for determining cam and tappet specifications and angles.
| Identifier | ExFiles\Box 174\2\ img237 | |
| Date | 27th December 1937 | |
| WILCOX-RICH CORPORATION Division of Eaton Manufacturing Company Mr. W. A.{Mr Adams} Robotham December 27, 1937 1. Cam angle determined by the timing diagram. 2. Loading. From our experience the chilled-face type tappet will carry a load of about 400 lbs. satisfactorily; therefore, by knowing the loading and weight of parts you can determine the maximum allowable acceleration. F : Wt a : Wt/g (V^2 - v^2) ? 3. Acceleration. Acceleration is maximum at ǿ = 0° Cos. ǿ : 1 a' = (F'L cos.(A'+ǿ)) / (w/30 (rso)^2) F'c = (w/g) * (U/30)^2 * (1/r) where U equals the maximum cam speed in R.P.M. 4. Find nose eccentricity: Eg equals the bearing diameter divided by two, minus nose radius. Nose radius should not be less then .050. Clearance should be allowed between nose and bearing outside diameter. 5. The flank angle can be determined from the following: Sin ǿmax. = (D/2) / F'L Solve for ǿ 6. The nose angle determined by formula For tappet diameter D, allow largest that can be utilized and subtract approximately 1/16"; this being the amount allowed over the theoretical for misalignment, etc. Sin ⍬max. = (D/2) / Eg Solve for ⍬ 7. Angle of involute: ß = a - (ǿmax. + ⍬max.) 8. Lift on nose: Lh{Mr Haworth} = Eg x (1 - cos. ⍬) | ||