Restraint device for reducing an abrupt sideward movement and/or forward movement of an occupant

A restraint device, in particular for a motor vehicle, for reducing an abrupt sideward movement and/or forward movement of an occupant in the case of an impact with an airbag which is inflatable by means of a gas generator when an accident situation occurs, wherein:

• the airbag is arranged by means of at least one fastening element at an associated vehicle seat fastening point on a side of a side rest of a vehicle seat facing a vehicle interior,
• the restraint device comprises at least one anchoring strap, the one end thereof being fastened at an airbag fastening point to the airbag,
• the airbag has at least one side chamber and one shoulder chamber which are connected together, wherein in the inflated state of the airbag the side chamber and the shoulder chamber form different main extension planes which run at an angle to one another,
• the airbag fastening point is configured on the shoulder chamber so that the anchoring strap is fastened at one end to the shoulder chamber,
• the other end of the anchoring strap is fastened at an anchoring point to the vehicle seat,
• the shoulder chamber comprises two regions which transition into one another at a bending line of the shoulder chamber and which together form a reverse U-shaped region, a base of the reverse U-shaped region in the inflated state of the shoulder chamber forming an upper end of the shoulder chamber,
• a first region of the two regions is connected to the side chamber and a second region of the two regions is folded back onto the side chamber,
• the second region of the shoulder chamber faces the occupant,
• the second region of the shoulder chamber is connected to the side chamber by means of a sail-like portion,
• the sail-like portion is configured to be triangular to protect the occupant from any forward movement during the occurrence of an accident;
• and
• the two regions of the shoulder chamber which together form the reverse U-shaped region are arranged substantially symmetrically to one another, wherein the plane of symmetry between the two regions includes the bending line and forms a main extension plane of the shoulder chamber.