sash rail 36 between the two openings 150 the top wall 144 rises upward to form an opening 146 the opening 146 is proportioned to receive the cam 46 a dog or tooth 148 projects downward from the top of the arch of the wall 144 the dog 148 is captured by the inclined portion 79 of the cam 46 as the cam moves from the open to the closed position eventually being positioned behind the rim 78 when the sashlock is in the locked position shown in fig3 b the operation of the lockable sash assembly 20 may be explained in detail by referring back to fig3 a and 3b when the sash assembly 20 is in its unlatched condition the cam 46 is positioned entirely within the internal chamber 58 of the sashlock housing 44 and so is clear of the space 32 between the lower and upper sashes 24 and 26 respectively as shown in fig2 the cam hub 39 s flat edge 88 the rim 39 s rounded point 96 and the lock tab 84 are positioned flush with the inner wall 52 see fig3 a when the cam 46 is in this window openable position the cam 39 s stop pin 82 abuts the corresponding position set tab 70 of the housing 44 see fig4 c and fig5 a and 5d the lever 48 is positioned in a position corresponding to the window openable position of the cam 46 in fig3 a the locking device 50 is shown in the unlocked state in which the block pin 132 is clear of the path of the cam 46 as was explained above the locking device 50 is positioned radially outward from all portions of the cam 46 when in the unlocked state accordingly when the locking.