The Sprinkler Hammer

I rolled my tires clear of the wool rug and eased down the front porch ramp onto the open sidewalk. At the edge of the turf verge, a brass impact sprinkler head stood mounted low on a steel spike, perfectly level with my handlebars. I cut my roll and pulled alongside the cold metal body. A counterweighted brass hammer was pinned to the side by a slender torsion spring. Leaning low over the tank, I nudged the spoon-shaped deflector back with the firm tip of my wing. The coil tightened with smooth resistance. When I let go, the hammer snapped forward, striking the nozzle collar with a crisp, hollow ping.