Concentric V-groove coupling

A transmission drive-line stage comprising:

• a torque input member;
• a torque reactive member;
• a torque output member;
• and
• a pair of torque couplings configured to transfer torque between the torque input member and the torque output member, each said torque coupling being configured to provide a respective gear ratio between the torque input member and the torque output member and comprising:
• a pair of clutch end members, each said end member including a set of concentric V-grooves disposed on a respective face thereof;
• a clutch centre member disposed between the respective clutch end members, the centre member being axially movable between the respective end members and including a pair of opposing surfaces, one of the opposing surfaces including a plurality of concentric V-grooves configured to mesh with the set of V-grooves of one of the respective end members, another of the opposing surfaces including a plurality of concentric V-grooves configured to mesh with the set of V-grooves of another of the respective end members;
• and
• an actuator coupled to one of the end members and being configured to simultaneously couple the end members to the centre member by engaging the V-grooves of both of the respective end members with the V-grooves of the centre member,
• wherein the centre member of one of the torque couplings comprises one of the opposing surfaces of the one torque coupling, another of the opposing surfaces of the one torque coupling and one of the end members of another of the torque couplings.