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).
Resolving interference issues in cam and roller bearing mechanisms by producing an eccentric cam axis.
Identifier | ExFiles\Box 106\3\ scan0429 | |
Date | 2nd December 1936 | |
- 3 - BY3/W.2.12.36. (Cont'd.{John DeLooze - Company Secretary} re-grind the roller bearings on the cams showing the hard spots, in the manner indicated, as the amount of metal we should require to remove from the races would be easily covered by the end adjustment which is possible. The following points are clear :- (a) There are two hard spots placed at equal distances from the central position of the roller on the cam, the actual interference in question occurring when the outer portion of the double roller moves across the centre line. This interference is due to the fact that the form of the cam is produced from one centre and the axis of the fulcrum is between this centre and the longitudinal axis of the cam, the cause of the trouble being that there is a greater angular movement on the arm carrying the follower roller than there occurs on the cam itself for the same linear movement. (b) It is, therefore, evident that with the two interference points existing, we cannot "set up" the follower roller into the cam on its central position, as the interference point would then be the limit of the mechanism. The simple suggestion I have made to produce the roller bearing axis of the cam eccentric with the axis of the thread would enable us to set tight on the centre line as the interference point would be moved back by the eccentricity as the cam revolved, and permit the roller to pass across the face without interfering. Having produced a number of eccentrically ground cams by modifying cams which have been delivered with interference points evident, by means of a special eccentric mandrel, we could then supply the mandrel in question to the Adamant Company and insist on their using it, as the cam would cost no more to produce by this method than by the present means. BY.{R.W. Bailey - Chief Engineer} BM | ||