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 document detailing the operation and specifications of a cylinder system related to a clutch mechanism.
| Identifier | ExFiles\Box 128\2\ scan0196 | |
| Date | 12th October 1933 guessed | |
| -2- enough to allow the clutch plates to come to their "cushion point" and is then restrained from further movement. The position reached by the piston is termed the "cylinder cushion point". Two systems of obtaining the cylinder "cushion point" are used: (a) in which the piston travel to "cushion point" is predetermined and fixed. (b) in which the piston is brought to its "cushion point" automatically, by drop in clutch spring pressure as the clutch plates come together. In the case of the fixed "cushion point" (a) manual adjustment is necessary to secure correct relationship between clutch and cylinder "cushion point". With automatic cushioning, after an initial adjustment the cylinder cushion point automatically follows that of the clutch throughout its life. Calculation of cylinder size and leverage is the same for either type but the automatic method requires a slightly longer effective piston stroke. It is desirable that the cylinder, pendulum and control valve should be assembled in one unit, as this simplifies the assembly on the car, particularly when "line assembly" is used. In some instances, due generally to restricted space forward of the rear engine bearers, it is necessary to fit the cylinder behind the clutch and it may be necessary to mount the pendulum and valve details on a separate bracket bolted to the dash board on engine; where this is necessary, particular attention should be paid to the rigidity of the bracket and its supports. CYLINDER CAPACITY. There are three standard sizes of cylinder: (a) 3.5/8" bore. (b) 4.5" " (c) 5.25" " The following table gives the total stroke and stroke after cushion for all standard cylinders. Note: The nett pull given by these cylinders is based on a vacuum in the intake manifold equivalent to 9" on a mercury column. This allows for use at any altitude or any time when the barometric pressure is low. The figures given for pull should not be exceeded in practice. | ||