Headrest adjusting device

A headrest adjusting device, comprising a hinge, a fixed base and a drive device, wherein the drive device is fixed on the fixed base and has an output end that is capable of sliding upwards or downwards, the hinge comprises a first rod and a second rod which are pivotally connected together, the second rod can be rotated or locked relatively to the first rod, and the first rod is driven by the output end of the drive device to move upwards or downwards, wherein a locking member and an elastic member are arranged between the first rod and the second rod, a positioning hole is provided at one end of the first rod, the positioning hole comprises a first tooth surface and a contact surface connected with the first tooth surface, the first tooth surface is in arc-shaped, a receiving hole is provided at one end of the second rod, the receiving hole comprises a first receiving hole and a second receiving hole which are communicated with one another, and a positioning slot is formed at one end of the first receiving area;

• the locking member comprises a retaining portion and a locking portion, the retaining portion is detachably inserted into the positioning slot to make the locking portion to swing in the first receiving area, the locking portion includes a second tooth surface extended into the positioning hole to engage with the first tooth surface, one end of the elastic member is received in the second receiving area, another end of the elastic member is pushed against the locking portion to the first tooth surface;
• an unlocking position is formed at a connection between the first receiving area and the second receiving area, and one end of the locking portion is pushed by the contact surface to slide into the unlocking position thereby disengaging the first tooth surface from the second tooth surface.