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).
Visit to Borg & Beck Clutch Works to discuss clutch rating, performance, and various designs.
| Identifier | ExFiles\Box 179b\2\ img230 | |
| Date | 3rd December 1932 | |
| De. From He/Aln. c. to By.{R.W. Bailey - Chief Engineer} c. to c. to Hdy.{William Hardy} Ha/Aln.1/MA. 3.12.32. VISIT TO BORG & BECK CLUTCH WORKS. X2200. On Monday we visited the Borg & Beck Works at Leamington following a visit to the Lockheed brake Works there. Gry.{Shadwell Grylls} and I discussed with their Mr. Burdon and others their views with regard to the rating and performance of clutches. We compared their own figures with what we had estimated for their 10 A1-3 clutch (which is suitable for our 20/25HP. car) and found a good agreement. The spring rating is 180 lbs. per in., total spring pressure 1350 lbs. We found a friction coefficient of .23 for their special material. They work to a value of .29 in their designs. The 10 A1-3 clutch which was sent to meet our requirement of 160 lbs.-ft. torque is designed for a maximum of 175 lbs.-ft., their practice being to allow a margin of about 10% above the required maximum. The fabric loading is 30 lbs.per.sq.in. They supply a whole range of clutches up to large commercial types. The size equivalent to our Peregrine is the 9 A1-G with 9.0 in. dia. fabrics and maximum torque of 135 lb.ft., fabric loading 34 lbs.per.sq.in. Regarding the flexible centre type of driven plate we learned that they do not recommend this in preference to the solid centre where the latter will suffice, but only offer it as a help in cases of troublesome torsional vibration. It cannot be fitted indiscriminately however, but has to be designed and developed to suit each particular job. They rely on the crimped plates carrying the fabric for smooth take-up which experience proves to be very effective. In the 10.A1 clutch which we have, the amount of warp in the plate is about .025". The flexible designs embody either rubber blocks or coil springs in the centre portion of the plate. We gathered however that in neither case did they aim at obtaining any damping action but only flexibility. They could not give any particulars of hysteresis but gave a figure of 3° deflection at 150 lb.ft. torque for a rubber centre plate suitable for the 10.A1 clutch. | ||