No trucks of a gross empty weight in excess of 5,000 pounds and no tractors, graders, steam rollers, steam shovels, front end loaders or other construction or earth moving equipment shall be stored or parked outside in any residential zone. Not more than one truck of a gross empty weight in excess of 5,000 pounds, tractor, grader, steam roller, steam shovel, frontend loader or other construction or earth moving equipment shall be garaged on any lot in a residential zone. No vehicles shall be displayed for commercial purposes in any residential zone.