Independent latching system for a transmission

An independent latching system adapted for use in a control system for a transmission having a plurality of hydraulically actuated clutches, the control system including 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 independent latching system comprises:

• a plurality of electro-hydraulic valve mechanism 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 opposed ends with one of the opposed ends connected to the respective hydraulically actuated clutch and being disposed between the electrically controlled proportional valve and the reservoir, the latching shuttle valve being movable in response to a force differential between its opposed ends;
• and
• a master latch valve mechanism connected between the source of pressurized fluid and the other opposed end of the latching shuttle valve.