18 on the drive train 20 moveable around the window by controlling teeth 22 of the handle as illustrated the drive train is also provided with a slot 24 in which is located a latch 26 of a key operated lock 28 as illustrated in this invention there is provided a safety detent generally illustrated as 15 comprising a spring biased catch or latching member 32 having a hook end 34 with a spring 36 pivotal about point 38 urging the hook end 34 leftwardly against a ridge 40 in the drive train 20 when the window is closed as illustrated in fig3 the drive train can move upwardly without any interference by merely moving the handle to the up position as illustrated in fig4 however the drive train cannot be moved downwardly because the latch 26 prevents such movement in fig4 the handle is shown in the up position which allows for the window to assume a tilt position as more fully described in my prior patent u s pat no 3 911 621 the latch 26 does not interfere with the movement of the drive train 20 and freely moves within the slot 24 provided for the purpose as can be seen in fig4.