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).
Visit to Gemmer Manufacturing Co. in Detroit to discuss steering gear designs.
| Identifier | ExFiles\Box 173\4\ img152 | |
| Date | 30th November 1935 | |
| COPY (Memo. from Da.{Bernard Day - Chassis Design}) DETROIT. 30.11.35. To E.{Mr Elliott - Chief Engineer} from Da.{Bernard Day - Chassis Design} Steering Gear. We went to the Gemmer Manufacturing Co. yesterday and saw Mr. Phillips. These are the people who are in direct connection with the Adamant Co., and it was to them Grylls had a letter of introduction from Com.Maltravers. Saginaw make under a licence from them, but are, of course, entirely separate, and claim to have progressed beyond them. Nearly 50% of the U.S. cars (including the G.M. group) use the Marles double tooth gear, and only about 3% the Ross (or Bishop) gear. This, I think, is different from the English distribution. Chevrolet are abandoning Marles and returning to a worm and section, of a very cheap and simple type, solely, as far as I could make out, on the ground of cost. But the Dubonnet suspension seems singularly free from steering joggles. Phillips confirmed many of the points learned from Saginaw, but there were some differences. They get a tight spot in the centre, as do Saginaw, of 2 1/2 to 3 lbs. 1 lb. of this is due to preloading the worm bearings, and the remainder to pressing the roller into the worm. The roller itself however, has no preloading, but is practically spinning free, but without measurable slack. Saginaw were emphatic that the preloading of the roller bearing was essential, and so were adamant. But Gemmer rivet the roller bearing pin into the rocker shaft, with a special machine which first closes the bearings without slack or preload, and it is this practice, I think, which causes them to dislike preloading the roller to a definite amount. Though the tight spot on the steering wheel rim is of the same value as Saginaw, the resulting irreversibility is not the same, Gemmer failing to hold a static load of 32 lbs. on the pendulum lever, where Saginaw hold 100 lbs. Another difference is that Gemmer work on the inside faces of the roller and not on the outside, having tried the outside. The reason they give for this is that ( as we already knew, of course), there is a point in going from the centre to the locks with outside contact, where you pass from the outside to the inside, and this, they say, may result | ||