Report and advertisement for the Millam Free-Wheel and Sprag system.
| Identifier | ExFiles\Box 6\2\ 02-page052 | |
| Date | 1st January 1928 | |
| Left Page: Report on Millam Free-Wheel and Sprag BY HENRY E. {Mr Elliott - Chief Engineer} MERRITT, D.Sc., A.M.I.M.E., A.M.I.A.E., Gear Technologist. THE "MILLAM" PATENT FREE-WHEEL AND SPRAG. The "Millam" Free-wheel is a device which, whilst making use of the principle of the roller and wedge, carries out that principle in such a way as completely to eliminate the objections to which this device has been subject in earlier and conventional forms of construction. In these conventional constructions, it is commercially impossible to ensure a degree of accuracy or a method of functioning which will ensure that the load is equally divided between the several rollers; as a result, the surfaces of the driving members tend to become indented and the ratchet functions erratically, or not at all. The unequal load distribution is also liable to produce heavy lateral loads on the bearings, and for the necessary margin of safety demands an unduly heavy design. The "Millam" Free-wheel is unique in that, firstly, the construction lends itself to accuracy of manufacture, since the driving wedge-members are separate parts which can be made similar to each other within close limits; and, secondly, it embodies a new load-equalising principle. All the roller reactions are transmitted to a floating ring, which equalises the loads between the rollers and eliminates radial load on the bearings. Furthermore, the wedges retain their correct relationship of position round the periphery of the driven drum through a simple spring ring device, and thus come into action simultaneously. The design of "Millam" Free-wheels has been the subject of detailed mathematical analysis, particularly as regards the intensity of pressure between the surfaces of the rollers and the co-acting members. The values of these stresses are conservative, and do not exceed the corresponding surface stresses between the teeth of gear box gears or between the rollers and races of bearings. Owing to the almost entire absence of shock, therefore, the free-wheel, whilst being compact in size, has an ample margin of safety. In operation, the free-wheel fulfils all the claims made for free-wheels in general, in facilitating gear changing, reducing petrol consumption, and giving delightfully quiet coasting. The "Millam" Free-wheel is perfectly silent under all conditions, and whilst free-wheeling there is a minimum of friction; whilst, by a simple device, the free-wheel can be made positive in both directions, so that in emergency the engine is available as brake. A unique feature is the incorporation of a sprag device, which is very ingeniously operated by the mechanism which disengages the free-wheel. The value of this sprag is not confined to its convenience to ordinary motorists when stopping and starting on hills; it constitutes a safety device of the greatest importance where passenger-carrying vehicles are concerned. It is the considered opinion of the writer that the "Millam" Free-wheel and Sprag combines, in the most mechanically sound, simple and reliable form yet introduced, all the advantages of the free-wheel, with the added safety of the sprag, and is a device in which the fullest confidence may be placed. HENRY E. {Mr Elliott - Chief Engineer} MERRITT. Right Page: Arrol-Aster Cars fitted with Millam Free-Wheel and Sprag (Patented throughout the World). We will teach anyone to change gear perfectly in this car in five minutes. The car will not run backwards on a hill. It is as simple to start off on a steep hill as on the level. Capital outlay returned in about six months on petrol and oil saved. Ask for a Demonstration and We Will Convince You. OLYMPIA MOTOR SHOW, 1928 STAND No. 104 Handwritten text: x523 | ||
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).