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 description of the front brake and servo system operation, including deductions on brake release.
| Identifier | ExFiles\Box 66\5\ scan0122 | |
| Date | 15th October 1927 guessed | |
| 2 FRONT BRAKE SYSTEM Consists of rod from bottom of T-equalizer to front-brake equalizer, the front brake equalizer itself, brake ropes, levers and shafts on axle, and operating mechanism on brakes. This system is held rigid by the action of the "rat-trap" springs on the front-axle operating shafts (hidden within the axle) pulling against the stop on the differential of the front-equalizer. SERVO SYSTEM Consists of the "driven" plates of the servo, the two operating levers and pull rods mounted on the servo shaft on the inner side of the bridge, the "Tee-equalizer" with its suspension-arm, and the rod from the upper arm of the Tee equalizer to the loose lever on the "pick-up" shaft. When the brakes are off the Tee-equalizer still has a small range of movement shown in the sketch. The extreme forward position of the suspension arm lifts the operating levers of the servo off their pins and takes up the slack on the pick-up shaft as shown. The extreme rear-ward position of the arm puts the operating levers in contact with the pins on the servo and swings the loose lever on the pick-up shaft into the position shown, with slack in the pick-up mechanism. The position of the suspension arm when the brakes are engaged however, depends on the relative adjustment of the front and rear brakes, wear of brake liners etc., and so may be either forward or back (or may be in the position of rest so that the arm does not move at all during operation of the brakes) See sketch S.K. 122. From the above we can make the following deductions:- (1) SUDDENNESS OF RELEASE OF RAKES Sudden release will always tend to let the T-equalizer drop into the "rearward" position referred to above with the operating levers touching the pins. It is impossible by any adjustment in assembly to arrange that these levers shall be held clear of the pins when the brakes are released. (2) GENTLE RELEASE OF BRAKES. With any considerable friction in the suspension arm, the position of the servo system when gently released depends entirely on the relative adjustment of the front and rear brakes. If there is small clearance in front and large clearance at the rear the system will come to rest in the "forward" position with the operating levers clear of the pins. If there is large clearance in front and small clearance at the rear, the system will come to rest in the "rearward" position, even if released gently. | ||