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).
Proposed modifications for a four-wheel brake system on a 40/50 model.
| Identifier | WestWitteringFiles\K\November1923\ Scan119 | |
| Date | 22th November 1923 | |
| R.R. 235a (100 'T') (S.H. 159 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 TO HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} RG.{Mr Rowledge} FROM R.{Sir Henry Royce} er to OJ. DA.{Bernard Day - Chassis Design} FOUR WHEEL BRAKES. (40/50 ETC.) X1557 FRONT SPRINGS. It is a decided advantage to increase the length of the road springs from 42" to 45" and it appears that this can be done (keeping the axle in the present position) by fitting up a front horn which naturally lengthens it, and by fitting dump irons and shackles at the front. The front eye can be a rolled eye. The back end of the spring is to be anchored without shackles, is to be used as a radius rod, and should have the eye forged in a direct line with the upper plate - (solid eye.) STEERING LOCK. By using the spring as a radius rod we can then cancel the radius rods and obtain the same lock as at present, or slightly more (owing to the track being 1" wider,) using the same steering gear as at present with very slight modifications to clear the anchorage of the extra long spring. A drawing of the spring and front horn will be sent this week BRAKE SHOES. It is suggested that the brake shoes should be floating fulcrum type consisting of one shoe of about 120° and another shoe of about 150°, this long shoe being jointed about 40° from the operating end. We propose to use such shoes for both front and rear brakes, fitting the front ones so as to be self servoing backwards, and the back ones to be self servoing forwards. (Scheme sent.) RUBBER BUFFERS. Since we are going to use 25% stiffer front springs we are proposing that some of the bump be taken up by rubber. Instead of using the present 1 1/2" rubber which we estimate gets squeezed to 3/4", we propose using 2 1/4" rubber which gets squeezed to 1 1/4". BEND OF ROAD SPRINGS. We estimate the maximum braking effect on each of the front wheels to be equivalent to not more than a horizontal load of 400 lbs. We estimate that the top plate of the road spring which is taking this horizontal effort will be 14" above the ground. Our brake then consists of 5600"lbs. This divided by the length of the spring makes a difference of vertical load on the spring eyes of 133 lbs. so that assuming that if each end was carrying 600 lbs. one would be increased to 665 lbs. and the other decreased to 535 lbs. Such a bending effect on the road spring is very little compared with the maximum bend on the bump. TEST. We think that you certainly ought to test all brakes preferably by electro motor, and find the rope pull necessary for the braking effort desired. R.{Sir Henry Royce} | ||