formed in the adjacent side of the bolt the latch operator may be rotated manually by means of a lever 76 projecting radially from the ring 70 through an opening 78 in the housing when the bolt actuator is in the position of fig4 and 8 pin 72 retains the bolt in the retracted or inoperative position rotation of the bolt to the fig9 position causes pin 72 to move the bolt to its extended position in which it may project into a suitable recess in the door jamb to lock the door it will be noted that the ring 70 has an arcuate notch 71 in its outer edge portion of about 90 u00b0 in extent the ring is in a plane coinciding with the arcuate peripheral edge 30 of latch 12 see fig8 and 9 when the bolt actuator is rotated to extend the bolt the unnotched portion of the ring 70 extends behind this peripheral edge portion 30 as seen in fig9 positively preventing the latch from being retracted hence the door is prevented from being opened not only by the bolt 16 but also by the locked condition of the latch the effect is that of a double.