Preventing movement of an article along a shaft

摘要

To prevent movement of an article 138 along a shaft 134, an element 140 engages the article 138 and engages the shaft 134 at locations 144 and 146 forming an angle no greater than tan<-1> mu . The locations 144 and 146 of engagement lie in a first plane extending perpendicular to a second plane in which lies the axis of the shaft 134. A third plane extends perpendicular to the axis. The angle is between the first and third planes. mu is the coefficient of friction between the element and the shaft.