Patent ID: 8393682

Claim:
A seat back locking device for an automobile, the seat back separating a vehicle compartment from a luggage compartment being configured so as to be capable of being changed from an upright position to a folded-down position, in which the seat back is folded down to the vehicle front side, and vice versa, comprising: a locking mechanism for locking the seat back in the upright position; a rotary locking knob for unlocking the locking mechanism; a key cylinder capable of locking and unlocking the locking knob, wherein a contact part which comes into contact with a contacted part provided on the locking knob is connectingly provided integrally with a cylinder body of the key cylinder so that a changeover can be accomplished between a locked state in which the contact part comes into contact with the contacted part to inhibit the rotation of the locking knob and an unlocked state in which the contact part does not come into contact with the contacted part to allow the rotation of the locking knob; wherein the locking device is configured so that the cylinder body is rotated around an axis of the cylinder body to accomplish the changeover between the locked state and the unlocked state; wherein one end part on an opposite side to an opening of a key insertion hole of the cylinder body is caused to face to the contacted part of the locking knob; wherein the contact part is provided in the one end part of the cylinder body; and wherein a notch, which avoids interference of the contacted part with the one end part of the cylinder body caused by the rotation of the locking knob in the unlocked state, is formed in the one end part of the cylinder body.