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 'Hartford' friction damper as a cure for car jagging when braking, including test data.
| Identifier | ExFiles\Box 51\4\ Scan017 | |
| Date | 3rd January 1922 | |
| contd:- -2- Hs {Lord Ernest Hives - Chair} 1/LG3.1.22. is the best cure we know of for preventing a 40/50 H.P. car jagging or dithering on the road when the brake is applied. The 4-stage shock absorber does not overcome this complaint to any great extent. All we claim for the "Hartford" friction damper is that it can easily be fitted to our chassis and is the most effective means we know of for making customers satisfied with their cars with the least expense to the Company or to the customer. We have carried out a test to show how the friction in the Hartford shock absorber varies owing to the decreased lever-age as they open out - (Diagram of a shock absorber arm with dimensions <-10.3-> and ^ inches) Inches of movement. lbs. applied. From 1" to 7⅞" 21.75 lbs. " 7⅞" " 11½" 24.5 " " 11½" " 13¼" 27 " " 13¼" " 14½" 29.5 " " 14½" " 16½" 36 " " 16½" " 17⅛" 41.75 " " 17⅛" " 17½" 46.75 " Hs. {Lord Ernest Hives - Chair} | ||