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).
Patent situation for double-acting hydraulic shock dampers in the UK and USA.
| Identifier | ExFiles\Box 28\1\ Scan199 | |
| Date | 20th January 1931 | |
| Copy. X832. R.{Sir Henry Royce} Sg.{Arthur F. Sidgreaves - MD} c to Wor.{Arthur Wormald - General Works Manager} c to Hs.{Lord Ernest Hives - Chair} c. to BY/NW.{N. Walker - Patents} BY4/G.20.1.31. X.235. X.832. SHOCK DAMPERS - RE PATENT SITUATION. With reference to Rl/M.6.1.31. the patent position is as follows :- 1/- Re what we control and why in double acting hydraulic damper. Our British patent 27224 of 1908 was our greatest hindrance, being cited against us on most of the points we sought to obtain protection for. In this connection you were right in assuming your recollections might be at fault, as 27224 did not discharge into a common reservoir but from one side of the piston to the other, through a spring controlled relief valve of generous dimensions. The one loop-hole we had which Mr. Claremont took full advantage of was that our earlier patent was for a single acting damper, and by stressing this aspect of the matter Mr. Claremont succeeded in getting most of the points you indicated under heading (1) in Rl/M.6.1.31. protected in our patent 266496, but if the matter were seriously raised in the courts it is doubtful in my opinion whether we should maintain our claims under 266496 in view of 27224/08. If we are prepared to fight on 266496 we may be able to hold up Delco Lovejoy's scheme in this country on the combined features you enumerate in paragraph (1) Rl/M.6.1.31. 2/- With regard to U.S.A., we found very much more had been done, and we had a number of citations on each feature we claimed, and finally were only able to get a 'thin' patent covering our detail construction so that whilst Delco Lovejoy infringe on our British patent as granted, they are clear of our U.S.A. patent. | ||