Head-protecting airbag device

1. A head-protecting airbag device mountable on an upper periphery of a window of a vehicle inside the vehicle, the airbag device comprising:

an airbag that is deployable over the window, the airbag being folded up in such a manner that a dimension between an upper edge and a lower edge of the airbag as deployed is reduced;

a mounting bracket that is disposed at a vicinity of the upper edge of the airbag and is used to mount the airbag on the upper periphery of the window of a body structure of the vehicle, the mounting bracket including a mounting section to be secured to the body structure of the vehicle and a joint plate section that is disposed at a root region of the mounting section; and

a case for housing the airbag such that the mounting section of the mounting bracket as disposed on the airbag protrudes out of the case, the case being fabricated from synthetic resin and comprising an opening for receiving the airbag at least at a lower region thereof; and an engaging region which is engageable with the joint plate section of the mounting bracket;

wherein:

the joint plate section is formed generally into a plate extending generally along an up and down direction and includes a retaining hole; and

the engaging region of the case comprises:

an insert slot that allows the joint plate section to slide therein generally in the up and down direction when the airbag is housed in the case;

a retaining pawl that protrudes generally in an inboard-outboard direction to be inserted into the retaining hole of the joint plate section and retains the joint plate section and prevents the joint plate section from being dislocated in the up and down direction; and

an inboard side pressing surface and an outboard side pressing surface that press the joint plate section on the inboard and outboard sides and prevent the joint plate section retained by the retaining pawl from being dislocated in the inboard-outboard direction.

2. The head-protecting airbag device of claim 1 , wherein:

the retaining pawl includes a neck region that is disposed generally along the up and down direction and a pawl body that protrudes out of a leading end of the neck region generally in the inboard-outboard direction and is inserted into the retaining hole and retains the joint plate section; and

a surface of the neck region facing towards the joint plate section constitutes the inboard side pressing surface or the outboard side pressing surface.

3. The head-protecting airbag device of claim 2 , wherein, in addition to the inboard side pressing surface or the outboard side pressing surface composed of the surface of the neck region, the engaging region of the case comprises an additional inboard side pressing surface or outboard side pressing surface at a position distant from the retaining pawl in a front and rear direction and on a side the pawl body is protruding.

4. The head-protecting airbag device of claim 3 , wherein:

the pawl body protrudes out of the lower end of the neck region towards an outboard direction;

the insert slot is configured to receive the joint plate section from a lower side thereof such that the joint plate on is slid upward therein; and

the engaging region further comprises, on an outboard side of a region of the joint plate section disposed below the pawl body; an auxiliary holding surface that supplementarily holds the outboard side of the joint plate section.

5. The head-protecting airbag device of claim 2 , wherein:

the pawl body protrudes out of the lower end of the neck region towards an outboard direction;

the insert slot is configured to receive the joint plate section from a lower side thereof such that the joint plate section is slid upward therein; and

the engaging region further comprises, on an outboard side of a region of the joint plate section disposed below the pawl body, an auxiliary holding surface that supplementarily holds the outboard side of the joint plate section.

6. The head-protecting airbag device of claim 5 , wherein the engaging region further comprises an upper stopper surface that abuts against an upper surface of the joint plate section and prevents the joint plate section from being dislocated upward.

7. The head-protecting airbag device of claim 1 , wherein the engaging region further comprises a pair of front-rear stopper surfaces that abut against a front surface and a rear surface of the joint plate section and prevent the joint plate section from being dislocated in a front and rear direction.

8. The head-protecting airbag device of claim 1 , wherein:

the airbag comprises a bag body and a joint tab that is formed into a loop out of a flexible material and protrudes upward out of an upper edge of the bag body for coupling with the mounting bracket; and

the joint tab is coupled with the mounting bracket by being inserted through the retaining hole of the mounting bracket.