to the movement of the piston 156 fig1 schematically depicts the hydraulic latch release control unit 162 used with the hydraulic latch release alternative of fig7 a 7b and 7c as shown in fig1 the lines 94 and 96 lead from the reset signal control 38 shown in fig9 line 94 leads to a positive potential v and line 96 leads to one terminal of a solenoid 172 the other terminal of the solenoid 172 is connected through line 166 to ground when electrical connection does not exist between line 94 and line 96 that is when the reset signal control 38 is in the operate position shown in fig9 solenoid 172 is not energized when electrical connection does exist between line 94 and line 96 that is when the reset signal control 38 is in the reset position shown in fig9 the solenoid 172 is energized the solenoid 172 controls the state of a two state hydraulic valve 176 hydraulic fluid line 158 leads from the front chamber of the hydraulic cylinder 154 shown in fig7 to one input to the valve 176 hydraulic fluid line 160 leads from the rear chamber of the hydraulic cylinder 154 to the other input to the valve 176 in its first state the state in which the solenoid 172 is not energized and the valve 176 is held in its first state by the spring 182 the valve 176 connects the hydraulic fluid line 158 to fluid line 184 which in turn leads to a hydraulic fluid pump 186 which pumps hydraulic fluid through fluid line 190 from the reservoir 192 into the line 184 in.