Restraining device, restraining assembly and seat unit

A restraining device of a seat unit, which seat unit further comprises a vehicle seat with a seating and a backrest adapted to support a person seated in the vehicle seat, said restraining device comprising:

• an airbag cushion being deployable to a deployed state, wherein said airbag cushion comprises a first part having a backrest-proximate first end,
• wherein in the deployed state, said first part:
• is configured to extend from the backrest-proximate first end thereof in a first direction over a shoulder of the person sitting in the vehicle seat to a backrest-distal second end (30b) being located in front of the person's head and/or torso, and
• extends in a second direction from a person-outer third end to a person-inner fourth end,
• wherein the airbag cushion additionally comprises a second part being connected to the first part, and a third part being connected to the first part and to the second part, wherein in the deployed state:
• said second part extends in a third direction from a fifth end to a sixth end and from a backrest-proximate seventh end to a backrest-distal eighth end, such that at least an upper section of said second part is configured to extend laterally of the person's head, and
• said third part extends in the second direction from a person-outer ninth end to a person-inner tenth end, such that at least an upper section of said third part is configured to face the person's face;
• and
• the restraining device further comprises a first belt for securing the airbag cushion to the vehicle seat, the first belt and the airbag cushion forming a restraining assembly, the first belt secured at a first end to the backrest and at a second end to the seating, and the first belt further configured to extend over an upper surface of the first part and through the third part.