It shall be the duty of the occupant of any premises within the limits of the city to keep the sidewalk in front of the same at all times clear of boxes, wood or other encumbrance or obstruction to travel, except that such occupants when receiving or shipping goods may temporarily occupy such portion of the sidewalk as is necessary for that purpose leaving a passageway open at all times. (Ord. 5 Art. 3 § 5, 1909)