Retractable leash with automatic locking and unlocking function

A retractable leash with automatic locking and unlocking function comprising

• a housing;
• a spool disposed inside the housing and with a cord wound therearound, wherein the spool is rotatable in either an unwinding direction to unwind the cord from the spool and a winding direction to wind the cord around the spool, and the spool is biased towards the winding direction;
• a braking means provided on the spool;
• a cord opening on the housing through which the cord exits the housing;
• a stopping means disposed inside the housing between the spool and the cord opening and rotatable between a locking position where a first portion of the stopping means engages with the spool and cooperates with the braking means to stop rotation of the spool towards the unwinding direction and an unlocking position where the stopping means is disengaged from the spool and the spool is rotatable towards either the unwinding direction or the winding direction;
• a biasing means which biases the stopping means towards the unlocking position;
• wherein a second portion of the stopping means abuts against the cord in such a way that tensioning of the cord by an external force actuates the stopping means to overcome biasing force of the biasing means to rotate to the locking position, and untensioning of the cord by the external force returns the stopping means from the locking position to the unlocking position.