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).
General description of Borg and Beck Type A-1 clutches, detailing their design, features, and specifications.
| Identifier | ExFiles\Box 128\2\ scan0113 | |
| Date | 28th January 1932 guessed | |
| GENERAL DESCRIPTION OF BORG AND BECK TYPE A-1 CLUTCHES. This line of clutches represents the most advanced thought in clutch design. The extreme simplicity and light weight, without sacrifice of ruggedness and efficiency, make an instant appeal to the practical engineer. They were especially designed to meet the requirements of modern service as imposed on clutches by eight cylinder and other popular high speed engines where combined weight of clutch and flywheel is an important factor -- also to fit advantageously into current quantity production methods. Weight has been reduced wherever possible except where it is a real virtue. Therefore, the pressure plate is made unusually heavy while the total weight has not been increased. This thought has also been carried through the design of flywheel, it being very light with its center of mass carried very close to the rear engine bearing. The flywheel design is also very well adapted to simple machining operations as the friction face is perfectly flat and is carried across the entire wheel diameter without any raised obstructions. If so desired, it can easily be ground to a smooth polished surface. In addition to this the nine and ten inch clutches are interchangeable on the same wheel by simply providing the necessary cap screw holes for both clutches. The unused holes will not interfere with the operation of either clutch. This feature will also apply to the interchangeability of the ten and eleven inch sizes. The extra heavy pressure plate insures rapid dissipation of heat generated through high speed clutch engagement, thereby insuring maximum facing life. The thrust springs apply pressure directly against this plate, but are protected against the effect of heat by being seated on raised ribs which permit air circulation around the end coils. This construction has proven very effective as well as extremely simple. Accurate balance of rotating weight is assured by the unique method used in centering the pressure plate in relation to the stamped steel clutch cover. This is accomplished by extending the three equally spaced lugs which are cast integral with the pressure plate, (the eleven inch size has four lugs) through rectangular slots in the side wall of the cover. This forms a positive and accurate means of centering the plate in relation to the cover and also makes a very simple and effective means of driving it. The integral pressure plate lugs mentioned in the preceding paragraph also serve as part of the releasing machanism, they being machined in the form of a hook which provides a surface against which the release levers contact. The reinforced stamped steel levers are suspended from the clutch cover by means of three adjustable eye bolts. A pin is inserted through the hole of this eye bolt, forming a cross, and is the fulcrum point for the release lever. The forward end of the eye bolts are guided in holes drilled in the back side of pressure plate in such manner as to form a guide for alignment of levers. The driven member is made as light in weight as possible without impairing strength. This insures ease of gear shifting by reducing gear clashing to a minimum. For all general service requirements this is a non-adjustable clutch. The adjustment is provided for use in the course of assembly to establish the correct lever position and great care is exercised in setting the bearing contact points of the levers in accurate plane. This insures accurate parallel relation between the friction faces of the pressure plate and flywheel which is essential to smooth performance. All service adjustment should be made on the pedal. It is only necessary to provide ample clearance between floor board and pedal to allow for wear-in, and insure full clutch engagement. These clutches are manufactured in nine, ten and eleven inch diameters. The nine inch size is recommended for transmitting up to 135 lbs. ft. torque, while the ten and eleven inch sizes are rated at 175 and 220 lbs. ft. respectively. If further information is desired, our Engineering staff is at your service. The Borg & Beck Company | ||