Patent ID: 7537249

Claim:
A latch device for a door on a vehicle body, comprising: a latch having an engagement groove configured to receive and engage with a striker such that an opening movement of the door with respect to the vehicle body is restricted when the striker is engaged with the engagement groove; a ratchet configured to rotate about a ratchet axis and to engage with the latch; a base plate having a receiving groove configured to receive the striker; a switch lever at an open end of the receiving groove, wherein the switch lever is configured to rotate about the ratchet axis independently of the ratchet from an advanced position at which the switch lever closes an open end of the receiving groove, such that the striker is prevented from entering the receiving groove, to a retreated position at which the switch lever leaves the open end of the receiving groove open as the striker enters the receiving groove; a first detecting unit configured to engage with the switch lever and to detect that the switch lever is at the advanced position when the first detecting unit is in engagement with the switch lever, and to detect that the switch lever has moved away from the advanced position towards the retreated position when the first detecting unit is no longer in engagement with the switch lever; a second detecting unit configured to engage with the latch and to detect whether the latch is in a half-latch state in which the door is not completely closed with respect to the vehicle body but the opening movement of the door with respect to the vehicle body is restricted; and a third detecting unit configured to engage with the ratchet and to detect whether the ratchet is at the half-latch state, wherein the latch device is configured such that when the second and third detecting units detect that the latch and ratchet have moved to the half-latch state after the first detecting unit has detected that the switch lever has moved away from the advanced position towards the retreated position a latch actuator is driven to move the latch, the ratchet, and the striker into a full latch state in which the door is completely closed with respect to the vehicle body.