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).
Design and application of test rigs for windscreen chains and leaf springs.
| Identifier | ExFiles\Box 159\6\ scan0083 | |
| Date | 25th August 1940 | |
| To Ov. from Rm{William Robotham - Chief Engineer}/GB. Re/GB.1/ET.25.8.40 Thanks very much for your letter. It was good to hear from you again. My job was to have been chiefly rig testing car components, but other things have intervened. However, what follows is about car rigs. HEATH ROBINSON RIG - The first rig (now partly made but resting) is for Kelsey Hayes tests on wheels etc. and 45º axle shaft tests. Later on a rig for testing windscreen opening chains will be added. As now made these are not satisfactory on really high speed cars. The rig will consist of an adjustable out of balance weight rotating on a shaft whose axis lies parallel to the screen and in the centre plane of the car. The bearings carrying the shaft will be fixed to a steel plate, hinged at the top. The plate will represent the screen and will be opened and closed automatically and continuously. SPRING TEST MACHINE - A machine is to be made for life, rate and friction tests on leaf springs. This will be on the lines of your sketch of the Cadillac machine, but will be built higher. This will bring the springs to a more convenient height for settling and permit the fitting of a complete bath tub under the main frames. As there is no spring rate test machine here, the application of the correct load on the spring is to be made automatic by the method shown in the sketch. This appears to have several advantages over the usual procedure of removing the spring and checking on the Olsen every hour until the settling is less than 5 lbs. The first advantage is that the test will be continuous until the spring breaks. It will be possible to measure the settling while the machine is running. It would not be difficult to make the load applying weight work a trip to shut the motor off when the spring fails. Points about which doubts might be raised are:- 1. Bobbing up and down of the weight. Using a five to one lever the natural frequency of the weight will be below 40 cycles/min. The working speed will be at least four times this figure. With the help of the shock absorber the weight should therefore remain quite steady. 2. The varying rate of the spring and shackle will generally tend to reduce the spring load to a point below what it would be if the spring were rate tested and set up in the normal way. | ||