Dependent latching system for a transmission

A dependent latching system adapted for use in a control system for a transmission having a plurality of hydraulically actuated clutches, the control system includes a source of pressurized fluid connected to a reservoir and an electronic controller connected to a source of electrical energy and operative to receive signals from various system parameters and to direct control signals therefrom, the electronic controller is operative in response to a command input mechanism to selectively control engagement of respective ones of the hydraulically actuated clutches in the transmission, the dependent latching system comprises:

• a plurality of electro-hydraulic valve mechanisms connected to the electronic controller and to respective ones of the hydraulically actuated clutches and each being operative in response to receipt of an electrical signal from the electronic controller to proportionally control engagement of the respective hydraulically actuated clutches, each of the electro-hydraulic valve mechanisms includes a proportional valve connected between the source of pressurized fluid and the respective hydraulically actuated clutch, an electrically controlled proportional valve operatively connected to the electronic controller and the proportional valve, and a latching shuttle valve having one end and an opposed spring end and being disposed between the electrically controlled proportional valve and the reservoir, the latching shuttle valve being movable against the bias of a spring in response to receipt of a pressure signal at the one end thereof;
• a master latch valve mechanism connected between the source of pressurized fluid and at least various ones of the one end of the respective latching shuttle valves;
• and
• a logic valve arrangement operatively connected between the master latch valve mechanism and at least various ones of the plurality of electro-hydraulic valve mechanisms and in respective communication with at least various ones of the plurality of hydraulically actuated clutches.