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).
Assembly issues and proposed modifications for a main shaft and rocking lever.
| Identifier | ExFiles\Box 99\3\ scan0047 | |
| Date | 19th January 1938 | |
| -3- HPS{Horace Percy Smith - Experimental Factory Mgr}/WB.{Mr Brazier/Mr Bell}1/EP.{G. Eric Platford - Chief Quality Engineer}19.1.38. Main Shaft EX.29897/FB.3440. In assembling the main shaft it is necessary to feed it through two gland rubbers, two bearings, and at the same time locate the master - press fit - serration in the rocking lever, a load of approximately 15 tons being initially required to press the shaft into position. Since the rocking lever is split, no advantage is gained by having .005" diametral interference on the serrations, and we suggest that this be reduced to .002" with a -.002" limit. The main justification for press fit serrations in this instance is endwise location, but we feel assured that the fits herewith recommended together with the clamping bolt will amply serve the purpose, and assist production assembly. Incidentally, after pressing the shaft out, the pressing load was reduced from the initial 15 tons to 5 tons, when reassembled, and to 2 tons on the third occasion. Modifying the gland housings to permit assembly of the glands with the shaft in position, will further facilitate assembly and prevent damage to the gland rubbers. The latter complaint will be more fully dealt with under the section dealing with the glands. No groove was indicated on the drawing of the main shaft to receive the clamping bolt, and this had to be filed in in the case of the first pair of dampers. This groove was only .030" deep, and we see no reason why the mating hole in the rocking lever should not be raised slightly to eliminate the grooving operation on the shaft, since it cannot be considered as an efficient means of endwise location. The main lever clamping bolt groove is not shown on the shaft drawing and should be added. The only means of locating the position of the shaft during the pressing operation, is to set the shoulder of the gland level with the edge of the main casing, and it is advisable to provide a block, bored to take the protruding shaft, of the requisite depth to make the end of the shaft the means of location. Rocking Lever FB.3408. The question of interference fit of serrations has already been dealt with in the main shaft section. Since the rocking lever when clamped, takes the thrust load, the clearance between it and the bushes must necessarily be small. This is unfortunate, since it would facilitate assembly and machining - there would be no necessity to machine the bushes in position in the main casing otherwise - could larger tolerances be utilised at this point. continued | ||