Abstract: A mobile robot and a method by which a mobile robot crosses a crosswalk. The method by which a mobile robot crosses a crosswalk includes steps in which the mobile robot: detects the crosswalk; detects the movement of at least one pedestrian within a predetermined range from the crosswalk; determines, on the basis of the detected movement of the at least one pedestrian, whether the traffic lights of the crosswalk indicate a walking signal; and crosses the crosswalk if it is determined that the traffic lights indicate the walking signal.

Abstract: A spanner adapted for operative engagement with a hexagonal element, comprising a handle, jaws disposed at one end of the handle, the jaws defining first and second clamping surfaces and a contacting surface, the first clamping surface being continuous on one side of the jaws, the second, opposing clamping surface being disposed on the other side of the jaws, the second clamping surface being interrupted by a recessed portion which separates the second clamping surface into long and short clamping surfaces with the recessed portion being disposed therebetween, the contacting surface connecting the first and second clamping surfaces, whereby when the spanner is rotated in the clockwise direction the jaws engage the hexagonal element and when the spanner is rotated in the opposite direction, a protruding portion of the hexagonal element falls into the recessed portion, permitting the spanner to be repositioned for clockwise rotation.