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).
The design, application, and cost considerations of foamed latex cushions in various vehicles.
| Identifier | ExFiles\Box 132\3\ scan0229 | |
| Date | 9th January 1939 guessed | |
| - 2 - passenger traffic. Also, the vehicle service life of several hundred thousand miles made it possible to effect economies in the overall cost by a savings in maintenance charges. For the most part, applications were in the form of "full volume" cushions, i.e., a substitution of foamed latex for the previously used materials with the dimensions and shape remaining about the same. See Fig. #1. The cushions had molded corings on the bottom or back surface to remove weight and increase the deflection. The supporting base carried vents opposite the corings in the cushion for additional damping. Installations in the bus and railroad fields include seats, backs, head-rests, arm-rests, and mattresses, - practically all of which have been applied in relatively thick sections for maximum comfort. Truck and heavy equipment installations followed. These also, for the most part, constituted a full volume replacement, although in some cases a reduction in thickness was made. Where the reduction was a result of cost limitations, the remaining space was filled with a false base. In other cases, the space saved was used to advantage. Aircraft installations have included both seat cushion and crash pad units. The designs have varied considerably in attempting to reach the balance between maximum cushioning and minimum weight that is vital in this type of construction. Ambulance cot mattresses have been used in thicknesses varying from two and one-half inches to four and one-half inches. The original attempts at passenger car seating quite naturally followed the experience in other fields in the form of application. This full volume type of replacement presented difficulties principally of an economic nature. In attacking this problem of cost, the cushion sections were reduced by contouring the supporting base to get a maximum cushioning at the points of greatest loading. See Fig. #2. Worthwhile reductions were possible without sacrificing the riding qualities and considerable savings in interior body space were made possible. However, the cost problem was still in evidence, partly due to the retooling necessary to produce the supporting base and the rather radical changes required in production assembly methods. In addition, the reduced sections in such a construction did not provide the degree of static deflection and, in some cases, the appearance that had been accepted as necessary to produce an initial impression of comfort and luxury. Conceding that any change in these standards must be a gradual one, and still confronted with the problem of cost, further experimentation followed the theory of combining a thickness of foamed latex sufficient to conform to human contours with a secondary resilient supporting member to provide additional deflection and to take the bulk of the dynamic shocks. Numerous types of rubber and fabric, and rubber and metal combinations in the form of webbing or diaphragms, as well as many steel spring designs, have been tried as supporting members for foamed latex cushions. The section in Fig. #3 shows the general proportion of this type of construction. Where the supporting unit has an open surface, such as that of a coil spring, a covering or insulator is generally used to provide more uniform support for the foamed latex cushion. It is desirable that this insulator be sufficiently open to allow movement of air as the surface cushion is flexed. | ||