22 and or as slack in the webbing 20 is taken up by the rewind spring 34 the spool 32 then rotates a short distance in the winding direction as indicated by the arrow shown in fig9 the hub 214 then carries the clutch member 174 in the counterclockwise direction until the end portion 212 of the clutch member 174 is stopped by the block 216 the hub 214 thereafter continues rotating with the spool 32 in the counterclockwise direction in sliding contact with the base portion 210 of the clutch member 174 the end portion 212 of the clutch member 174 is thus moved off of the uppermost step surface 188 on the yoke 170 and the yoke 170 is released to carry the secondary flywheel 172 pivotally upward into the loading position under the influence of the coil spring 202 as described above the mass of the secondary flywheel 172 is applied to the primary flywheel 112 effectively to increase the inertia of the primary flywheel 112 when the secondary flywheel 172 is in the loading position the increased inertia of the primary flywheel 112 will cause the primary flywheel 112 to lag rotation of the spool 32 upon acceleration of the spool 32 in the unwinding direction at a second.