movement in fig5 and thereby retains the latch in its holding position of engagement with shoulder 74 on member 22 to now describe a cycle of use of the actuator assume that the device has been attached to valve 10 as illustrated and that the valve is initially in its closed position in which stem 18 extends horizontally broken lines in fig3 in that condition member 22 is urged by spring 23 in a clockwise direction as viewed in fig2 relative to the body structure 19 and to a position in which ears 50 of lost motion connector element 25 are in their broken line position of fig3 and the arcuate grooves 51 containing those ears are in their broken line position of fig3 further rotation of member 22 relative to the body structure in a valve opening direction is prevented by engagement of ears 50 with shoulders 55 on member 22 and by engagement of portions 150 of ears 50 with shoulders 65 on body part 20 fig4 when it is desired to open the valve and set the actuator key 88 is inserted into socket 89 in body part 20 so that the worm portion 90 of the key engages worm gear teeth 91 formed on the periphery of member 22 after which the key is turned to progressively rotate member 22 in.