Adjustment mechanism and headrest

A headrest for a vehicle seat, which has a headrest body, said headrest comprising:

• a base element designed for attachment to a seat,
• a head rest element with a head rest surface and
• an adjustment mechanism which is mechanically coupled to the base element and to the head rest element and is arranged between the base element and the head rest element for longitudinally displacing the head rest element in a first seat direction (X) and in the direction opposite to said first seat direction, wherein the adjustment mechanism comprises:
• a scissor lever, comprising:
• at least one first lever arm and at least one second lever arm which can be pivoted relative to one another about a common main pivot axis (S) at a common intersection point (P),
• a compensating lever arm is arranged at exactly one lever arm end of each lever arm so as to be pivotable about a compensating pivot axis (AS1, AS2) running parallel to the main pivot axis (S), wherein
• a free end of each compensating lever arm comprises an attachment structure for attaching the compensating lever arm to a body and
• a lever arm end opposite the compensating lever arm of each lever arm comprises an attachment structure for attaching the lever arm to a body
• wherein a pivotable arrangement of each compensating lever arm on the associated lever arm is implemented by a pivot bearing, wherein
• the pivot bearing comprises a bearing shell which has an opening (O) penetrating the bearing shell and which is arranged on the compensating lever arm or on the lever arm and a bearing body which is arranged on the lever arm or on the compensating lever arm and which corresponds to the bearing shell,
• wherein a distance between the bearing surfaces (L1, L2) of the bearing body which correspond to the bearing shell is smaller than an internal diameter of the bearing shell and larger than a width (B2) of the opening (O) and
• wherein a width (B1) of the bearing body extending at least substantially perpendicular to this distance is smaller than the width (B2) of the opening (O).