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).
Investigation into the cause and potential solutions for a clanking brake mechanism upon release.
| Identifier | ExFiles\Box 5\3\ 03-page283 | |
| Date | 12th November 1929 | |
| HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} X5360 R5/M12.11.29. C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} CLANKING OF BRAKE MECHANISM ON RELEASE X.7380 X.5360 Referring to H8/RM{William Robotham - Chief Engineer}5/AD81029., Mr Hardy says that as far as he can make out the clanking complained of is caused by the front brake gear flying back to its off position at a speed which is independent of the rate of return of the foot pedal as soon as the rear brakes have come on to their stops. This can only happen when the front brakes have more movement than the rear. The 20HP. would appear to be worse for clanks than the Phantom by reason of the slotted fork on the rear equaliser which does not act as a stop and cause the friction to function. By making the leverages equal and instructing that front brakes be adjusted, if they will stand adjustment, whenever the rear brakes are adjusted, the front movement might be prevented from much exceeding the rear at any time and so clanks would be minimised. Mr. Hardy ought to see a bad specimen if the foregoing is not correct. HA. says that the only trouble we can see is due to the extra travel of the front brake ropes when these brakes have excessive clearance. We understand that it is necessary for the swinging arm to return to its original position each time the brakes come off in order to avoid the slacking off of the brake gear to front or rear, with consequent thumps on application. The return of the swinging arm to zero means that with unequal movements the brake with the greater movement will be applied with twice the normal speed at the end of its travel, but the use of friction appears to either prevent this increase being attained, or in some way to prevent it being detrimental. SPONGINESS: Decrease the direct rear braking leverage as suggested many months ago. This will cure both sponginess and want of pedal clearance, which is fundamentally due to elasticity, which is difficult toreduce. I suggest :- (1) less direct back axle braking cures sponginess and | ||