Handle 1 and pinion 3 rotate about fixed axis A. Toothed rack 5 slides along fixed guides b-b. When handle 1 is turned in either direction and resistance to rotation is applied to pinion 3, the groove in disk 2 tightens coil spring 4. This reduces the diameter of spring 4 which grips disk 2 and rotation of handle 1 is thereby transmitted to pinion 3 which moves rack 5. If the handle is turned in the opposite direction, coil spring 4 is tightened again by the other side of tne groove in disk 2 and its diameter is again reduced. When, however, a force is applied to rack 5 and resistance to rotation is applied to handle 1, spring 4 is loosened so that its diameter is increased and it grips the bore in the bearing. This develops a friction force that impedes the transmission of motion from the rack to the handle.
$2330$SG,3L$