(under subclass 71.1) Apparatus provided with two of said components, the friction surface of one of the components facing in a direction opposite the friction surface of the other of the components, and further provided with two radially-extending surfaces spaced from one another on said rotating member, the components being located in the space between the radially- extending surfaces so that each of the radially-extending surfaces is adjacent to but spaced from a corresponding one of the friction surfaces, wherein the components are moved apart from one another to cause each friction surface to contact its adjacent radially-extending surface.