body 19 piston 26 and latch pin 24 are normally depressed into locked position as shown by a compression spring 29 fig6 above the piston when hook 20 is relieved of the weight of load 16 latch pin 24 may be retracted upward by supplying compressed air through line 15 to the lower end of cylinder 27 under the piston 26 then when hook 11 and the releasing hook 20 are lifted sufficiently to tension the cable 17 the hook 20 will rotate freely in the direction of arrow 28 to release the load cable 17 without any manual manipulation the objection to the release operation as thus disclosed in said u s pat no 4 095 833 is that it requires an air pressure line extending back from cylinder 27 to an air pressure reservoir in the crane the present invention involves the module 10 for supplying compressed air to air line 15 without requiring a compressed air line extending upward from hook 11 referring now to the module 10 in fig4 piston rod 14 is connected to a piston 30 in a vertical cylinder 31 piston 30 is normally retracted to its upper position by a compression spring 32 which presses upward against an abutment.