Lock apparatus of seat for vehicle

A lock apparatus of a seat for a vehicle, comprising:

• a striker adapted to be securely provided at one of a movable member of the seat and a fixed member fixedly provided relative to the movable member;
• a base adapted to be provided at the other of the movable member and the fixed member and including a first groove portion for inserting the striker;
• a hook including a second groove portion, the hook rotatably supported to the base about a first rotational shaft to pivot between a lock position at which the striker is engaged with the first groove portion and the second groove portion and an unlock position at which the striker is released from the first groove portion and the second groove portion;
• a pawl rotatably supported to the base about a second rotational shaft to engage with and disengage from an engagement portion of the hook, the pawl restraining a pivotal movement of the hook towards the unlock position while allowing the pivotal movement of the hook towards the lock position by being engaged with the engagement portion of the hook;
• a cam member rotatably supported to the base about a third rotational shaft and including a cam profile to be in cam contact with an operational portion formed at the hook for allowing the pivotal movement of the hook towards the lock position and for restraining the pivotal movement of the hook towards the unlock position;
• and
• a first biasing member for biasing the cam member to pivot in a direction in which the cam profile presses the operational portion of the hook;
• a second biasing member for biasing the pawl to be positioned at a pawl engaged position at which the pawl is engaged with the hook;
• and
• a link member for pivotally moving the pawl to a pawl released position at which the pawl is released from the hook against a biasing force of the second biasing member in association with a pivotal movement of the cam member in a direction in which the cam profile separates from the operational portion of the hook, the link member including a play portion for allowing a pivotal movement of the pawl relative to a pivotal movement of the cam member by a predetermined angle,
• wherein, when the hook is pivoted to the lock position, the striker is engaged with the first groove portion and the second groove portion is positioned between the first rotational shaft of the hook and the second rotational shaft of the pawl, and the pawl and the engagement portion of the hook are engaged at an opposite position of the first rotational shaft of the hook relative to the striker for supporting the hook relative to the striker at the first rotational shaft of the hook and at a position at which the pawl and the engagement portion of the hook are engaged.