Patent GB-731725-A (GB)
Title: Change speed gear
IPC: F16H61/14
Filed: 1953-01-07
Abstract: 731,725. Change-speed gear; friction clutches. SOC. SCIENTIFICA RADIO BREVETTI DUCATI. Jan. 7, 1953 [Jan. 10, 1952; April 1, 1952], No. 547/53. Class 80 (2). A friction disc clutch 4, which provides a direct-drive bridge between input and output shafts 1, 2 of a hydrodynamic torque-converter, is engaged by centrifugal masses 14, pivoted on a. sleeve rigidly connected with the output shaft 2 through the clutch outer casing, and causing axial movement of a cylinder 10, opposed in both directions by engagement of a spring-loaded detent 17 in notches 18, 20 in the cylinder 10 to locate the latter in invariable positions for disengagement and engagement respectively, movement between such positions occurring with a rapid snap action without any intervening slip position. The centrifugal masses 14 are opposed by torqueresponsive means, determined in Fig. 1, by reaction torque on the reactor of the torque-converter acting through fluidpressure means, and in Fig. 2, by an output torque-responsive ring 119 acting wholly mechanically. In Fig. 1 a presser-plate 8, acting rigidly on the clutch pack 4 through struts 7 on an end-plate 6, is actuated by the centrifugally-moved cylinder 10 through an intermediate freely-mounted flanged sleeve 19 and a compression spring 9, leftward centrifugal movement of the sleeve 19 being positively limited by the clutch casing whereby clutch pressure cannot exceed the compression of the spring 9 alone. A snap-ring 21 limits leftward movement of the presser-plate 8 in the disengaged position shown. The leftward centrifugal movement of the cylinder 10 is opposed also by a spring 11, bearing on an axially fixed flange 13 of the output assembly; by the spring-loaded detent 17; and by torque-responsive liquid pressure supplied to the cylinder 10 through a shaft-passage 26 by a pump 27 driven by the initial reverse rotation of the reactor 23 of the torque-converter The impeller 24 and turbine of the converter are fast respectively on the input and output shafts 1, 2. In the mechanically torque-responsive form, Figs. 2 and 3, the centrifugally moved cylinder 10 of Fig. 1 is replaced by a sleeve 141 having two notches for engagement with a detent 142, as before, but the leftward engaging movement of the sleeve 141 is now opposed by rightward torque-responsive thrust on an internal collar 171 applied through a strut 167 and diametral, pin 164 by a ring 119 axially slidable on ball-splines 117 on the driven member 102 and drivingly connected to a final output member 103 by engagement of rollers 158, mounted radially on the ring 119, with cam inclines 159, 161 on the output member. In the zero torque and speed position shown, the torque-moved collar 171 is out of contact with a similar collar 172 connected with the centrifugally moved sleeve 141, but during operation these collars abut, so that torque opposes the speed-responsive leftward movement of the sleeve 141 as before. The torque cam has two angles, one, 161, of 30 degrees, effective in torque-converter operation, the other, 159, of 45 degrees, during the lower torque of directdrive. The torque-converter has a two-stage turbine 126, 127 and its reactor 125 is supported by a one-way detent 136. A pump 105 on the input shaft 101 feeds the converter. Curves showing operating speeds, centrifugal, spring and torque loads are also given (Fig. 5, not shown).