Amplifying clutch

A clutch comprising rotatably mounted input and output members, a rotatably mounted first shoe supported to move axially relative to said input member and to turn angularly through a limited distance relative to said output member, coacting friction surfaces on said input member and said first shoe, said friction surfaces engaging one another and causing said first shoe to turn with said input member when said first shoe is moved axially toward said input member, said friction surfaces effectively releasing one another and enabling said input member to turn relative to said first shoe when said first shoe is moved axially away from said input member, selectively operable means for causing said first shoe to move axially toward and away from said input member, a rotatably mounted second shoe supported to move axially relative to said input and output members and coupled to rotate substantially in unison with said output member, coacting friction surfaces on said input member and said second shoe, said latter friction surfaces engaging one another and causing said second shoe to be turned by said input member when said second shoe is moved axially toward said input member, said latter friction surfaces effectively releasing one another and enabling said input member to turn relative to said second shoe when said second shoe is moved axially away from said input member, said clutch being characterized by means located between and engageable with said second shoe and said output member and coupled to said first shoe so as to be moved angularly through a limited distance by said first shoe and relative to said second shoe and said output member when said first shoe is initially turned by said input member, said last-mentioned means being effective upon being moved angularly through said distance to force said second shoe axially toward said input member without producing an axial reaction force against said first shoe.