away from the jamb normal to axis 64 downward past the platform or upward past the platform end 96 of arm 60 extends further from axis 64 than distance 98 of the shortest radius of axis 64 to the surface of bracket 50 so that arm 60 is prevented from rotating up to horizontal by impingement of end 96 against the bracket above the horizontal level of axis 64 so that lift expressed on end 124 by platform 110 is transferred to axis 64 by arm 60 when arm 60 is prevented from rotation by impingement of end 96 against the bracket it should be understood that this may comprise a protrusion of the surface of the bracket that prevents rotation of arm 60 so that lift expressed on end 124 by platform 110 is transferred to axis 64 by arm 60 when arm 60 is prevented from rotation by impingement of end 96 against the protrusion preferably the top 106 of arm 60 at end 96 extends farther from axis 64 than the bottom of the arm sash 46 containing glass 47 locked to shoe 34 by this configuration moves up and down with the shoe preferably the curve of hook 100 is on a radius 102 taken from axis 74 that is a portion of the circumference of a circle about.