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).
Technical memorandum discussing three different schemes for a bonnet lock on the 40/50 & 20HP models.
| Identifier | WestWitteringFiles\Q\January1927-March1927\ 6 | |
| Date | 10th January 1927 | |
| TO BX. (BA/EV.{Ivan Evernden - coachwork}) TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) C. to BJ. WOR.{Arthur Wormald - General Works Manager} R.{Sir Henry Royce} BONNET LOCK - 40/50 & 20HP ORIGINAL R2/M3.1.27. HS{Lord Ernest Hives - Chair} DESPATCHED FROM WW. 10.1.27. X8260 X5260 X 1140 If our new bonnet catches do not prove a success we shall require some scheme of catch which holds the bonnet to the pads - perhaps a spring plunger as shewn in Fig.4. We have now 3 schemes proposed for the lock - (1) Four existing pads-double catches on lock. (2) Clear central locking hook. (3) Six pads - central one for lock. We had abandoned (1) for various reasons, but I am now inclined to think it the best scheme: perhaps you at WW. can suggest something better than either. I have several objections to (2) as worked out, and I doubt if we can make it robust, and sufficiently clear, so I am having another try at (1). Fig. 1. Bonnet must be locked when key turned fully to stop R.H. as here shewn. [Diagram showing a bonnet locking mechanism between the Dash and the Radiator, passing through the Steering arch.] DIAGRAM LABELS: - Dash. - Steering arch. - Radiator. - DISTANCE AS THOUGHT BEST PROBABLY - This clearance does not vary much, neither does it in plan, while vertical clearance varies greatly: pads can have simple packing under. If the details are simple and robust (i.e. inexpensive and not likely to get out of order) we do not mind if many parts are needed, but the old lock had double catches, and was spring operated, and was not good because much work had to be done in unlocking. The above has same resistance approximately each way. LOCK BARREL. This must have a stop in R.H. direction for locking, and L.H. for unlocking, exactly one turn even after wear. (1) | ||