Horizontal bar hook

A locking device for retaining an end part of a horizontal bar configured for pull-up exercises, the locking device comprising:

• a housing having an inclined groove defined therein and an opening in communication with the inclined groove and an interior of the housing, the inclined groove defining a closed end and an open end, the open end being at one side of the housing, the open end being above the closed end so that the end part of the horizontal bar is able to be rested in the closed end of the inclined groove of the housing;
• a retaining block having a pivoting portion pivotally mounted in the housing, the retaining block being rotatable with respect to the housing between a first position where the retaining block is located in the inclined groove through the opening of the housing, so that two sides of the retaining block within the inclined groove are respectively defined as an abutting face toward the open end of the inclined groove and a retaining face toward the closed end of the inclined groove for retaining the end part of the horizontal bar, and a second position where the retaining block is moved out of the inclined groove into the interior of the housing for allowing the end part of the horizontal bar to be removed from the housing, the retaining block further having a controlling portion opposite to the pivoting portion for being operated from the first position to the second position;
• and
• an elastic member disposed in the interior of the housing for substantially biasing the retaining block in the first position;
• wherein the end part of the horizontal bar is inserted into the inclined groove of the housing by pushing the abutting face of the retaining block toward the second position, and the retaining block is restored back to the first position once the end part of the horizontal bar is rested in the closed end of the inclined groove.