Adjustment device for a head rest of a vehicle seat and vehicle seat

An adjustment device for a head rest of a vehicle seat, the adjustment device comprising:

• a back rest connection for mounting on a back rest,
• a head rest support,
• an adjustment mechanism for adjusting the head rest support in relation to the back rest connection in a longitudinal direction and a vertical direction, in an unlocked position,
• a locking device for locking a first component of the adjustment device in relation to a second component of the adjustment device which is adjustable relative to the first component,
• wherein the locking device comprises a release lever to be activated by the user, a blocking element pivotable by the release lever and a pivotable locking element, which are attached to the first component, and where, in the locked default position, a locking region of the locking element is received in or on a receptacle region of the second component, and an active blocking surface of the blocking element is in contact with an active locking surface of the locking element for blocking the locking element,
• wherein the release lever comprises a crash abutment surface which, the locked default position, is separate from the locking element and, in a crash situation, is in contact with the locking element and blocks the locking element when a crash acceleration of the second component occurs.