GB782924A - Improvements in or relating to centrifugal clutches - Google Patents

Abstract

782,924. Friction clutches. SOC. ANON. FRANCAISE DU FERODO. Dec. 16, 1954 [Dec. 21, 1953], No. 36511/54. Class 80 (2). To reduce the slip period of a centrifugal clutch whilst still maintaining progressive initial engagement, there is provided between a centrifugally-thrust presser-plate 73 and a friction member 90 elastically compressible means, such as an axially springy portion 102, Figs. 4 and 5, of the clutch-driven disc 90 itself, or of its facings, such elastic means being prestressed to a value 0.20 to 0.25 of the axial thrust necessary for transmitting maximum engine torque, and its resistance to complete compression being greater than said thrust. The eleastic means is of such rate that, at any given speed below that necessary for total crushing, the increase in elastic resistance due to a small compressive displacement is greater than the corresponding increase in centrifugal thrust resulting from the increase in radius of the masses. In all three forms described, two disc type, one cone type, the centrifugal masses are carried by a separate member clutched to input or braked for main clutch engagement and disengagement respectively. A clutch-driven disc 90, Figs. 4 and 5, incorporates the elastic means as a sinuous plate 102 riveted at 103 to a main plate 98, the plates 98, 102 having riveted to them the respective friction facings, all being formed as spaced segments. The elastic means is pre-stressed by a headed pin 105 limiting axial separation of the facings (Fig. 1, not shown). The compressive resistance at full crushing point is slightly greater than the engaging thrust necessary for non-slip engagement. In Fig. 3 the clutch disc 90 as above described is clamped against a driving flywheel 62 by a presser-plate 73 acted on, through pre-stressed springs 74, thrust-plate 72 and bearing-mounted cam-plate 71, by centrifugal masses 70 pivoted on an axially-fixed carrier 68, connected for rotation only with an axially-slidable sleeve 64 having a clutch-brake plate 66 which is braked for disengagement of the main clutch disc 90 by energizing an electromagnet 67, and clutched to input, for clutch engagement, by springs 65 rendered effective by de-energizing the magnet 67. In Fig. 1, not shown, the springs 74 and cam-plate 71 are omitted and the pivoted. masses act directly through axial struts on a plate which bears on the presser-plate through a single row of balls. In Fig. 2, not shown, a male cone, having a single elastically-mounted friction facing, is engaged with a female-driven cone by the axial separating thrust of centrifugal balls in radial slots in a clutch-braked carrier and bearing directly between outwardly convergent surfaces carried by the respective members, springs being interposed in the connection to the male cone and pre-stressed to a value equal to the full crushing resistance of the elastic mounting of the friction facing.