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).
Steering gear technologies, competitor practices, and component specifications.
| Identifier | ExFiles\Box 178\2\ img020 | |
| Date | 24th April 1940 | |
| Rm{William Robotham - Chief Engineer} - 2. Serial No.96. OY.2/D/Apr.24.40. 2) General Motors pay royalty to Gemmer on all worm and roller gears, which are made at Saginaw with roller assemblies from New Departure (of the angular ball-mounted type). Phillips says this royalty payment is so small as scarcely to be discernible in their costs. Yet G.M. appears always to have resented their dependency on Gemmer and to have taken up the Schmidt recirculator patents more as a means of escape than for any sound reason. In their way they have been just as un-progressive as Adamant. (These viewpoints from outside the Corporation looking in, are always refreshing) 3) Phillips guarantees to match the recirculator on cost, weight, strength, and efficiency, for any weight of vehicle at any time - no holds barred. Says Gemmer's minimum passable efficiency is now 70% and in a month may be 75%. That if any-one wants 86% they can have it, and he will accept special orders for 90% without fear of failure. They have small gears suitable for 10 H.P. Cars developed from Matravers' designs, which are improved for production methods and now being produced in Germany for the German Ford. Will send prints of these. 4) I enclose two prints of model 375, the big truck gear, showing the double and triple roller, the latter preferred for the heaviest vehicles because of higher efficiency and great angular range permitting use of a short pitman arm. The rubber shaft bearing is now replaced by the standard type of spring-loaded ball bearing with pressed races. 5) Endwise adjustment of rocker shaft is universal on Gemmer gears. Plain bearings are no longer oilite, because such porous bushings destroy some of the efficiency by allowing escape of the oil film. Burnished rolled-bronze bushings are preferred, with a rocker shaft of very high finish within 2-3 micro-inch, produced on the centerless grinder. Needle bearings on the rocker shaft are used for exceptional efficiencies. Ball races on the worm are used for exceptional efficiencies but the standard is taper roller as shown. Angular ball bearings demand close control of radius curvature to prevent climbing and cramping of the ablls. (We found this on the Adamant). (continued) | ||