The circular cam surface 30 of the flange 27 of U plate {HEAD ~ 24 circles} about {TAIL ~ screw} 28 and extends or projects in one direction on one portion 30 of the circle and projects in the opposite direction in the opposing portion 30 of the circle 
about
The circular cam surface 30 of the flange 27 of U plate { HEAD ~ 24 circles } about { TAIL ~ screw } 28 and extends or projects in one direction on one portion 30 of the circle and projects in the opposite direction in the opposing portion 30 of the circle
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