Lock device of vehicle seat

1. A lock device for locking a seat of a vehicle relative to a striker fixed to a vehicle body, comprising:

a base plate having a striker receiving recess for receiving therein the striker;

a latch plate rotatably connected to the base plate and having a striker catching recess for catching the striker, the latch plate being rotatable between a latch position to cause the striker catching recess to catch the striker and an unlatch position to cause the striker catching recess to release the striker;

a lock plate rotatably connected to the base plate and rotatable between a lock position to lock the latch plate at the latch position and an unlock position to unlock the latch plate; and

a cover member having a U-shaped flange formed thereon, the cover member covering one major surface of the base plate having the U-shaped flange thereof disposed on a peripheral edge of the striker receiving recess,

in which the latch plate comprises:

a latch plate proper including upper and lower finger portions between which the striker catching recess is defined, an upper surface of the lower finger portion including a depressed main portion located near the bottom of the striker catching recess, a raised leading end portion and a stepped portion provided between the depressed main portion and the raised leading end portion; and

a soft film that covers the latch plate proper except the raised leading end portion, the soft film covering the depressed main portion of the upper surface of the lower finger portion in such a manner that an outer surface of the soft film is flush with the stepped portion, the soft film covering the depressed main portion being deformed when pressed by the striker in the latch position, and

in which when the lock device locks the seat having the latch plate locked by the lock plate with the aid of the striker, the stepped portion of the latch plate is brought into a position that is proximate with an outer surface of the U-shaped flange of the cover member, and, at the same time, the upper surface of the lower finger portion of the latch plate and a bridge part of the U-shaped flange become parallel to each other.

2. A lock device as claimed in claim 1 , in which when the film on the depressed main portion is depressed by the striker, the stepped portion enhances a function to stop a movement of the striker toward a mouth of the striker catching recess.

3. A lock device as claimed in claim 2 , in which the raised leading end portion has a sloped upper surface that inclines toward the upper finger portion.

4. A lock device as claimed in claim 3 , in which the sloped upper surface inclines by a given angle relative to the depressed main portion of the upper surface of the lower finger portion.

5. A lock device as claimed in claim 4 , in which the sloped upper surface is rounded.

6. A lock device as claimed in claim 1 , in which the stepped portion is a portion where a shallow recess provided by the depressed main portion of the upper surface terminates.

7. A lock device as claimed in claim 1 , in which when the striker is latched and locked by the locked latch plate, the stepped portion is placed in-line with an outer surface of the U-shaped flange of the cover member.

8. A lock device as claimed in claim 1 , in which the seat is a seat back that is pivotally connected to a seat cushion mounted on a floor of the vehicle.

9. A lock device as claimed in claim 1 , in which the seat is a seat cushion that is pivotally mounted on a floor of the vehicle.