| 摘要 |
<p>A fire hydrant is designed to break away at the point of the coupling between the upper and lower standpipes when hit by a moving vehicle or the like, to reduce the chance for damage to the hydrant, the vehicle and possibly to the occupants of the vehicle. A valve push rod extends from a valve operating nut at the top of the hydrant down to operable connection with a hydrant valve so that the valve can be opened when water is to be delivered through the hydrant. To provide a breakaway connection for the push rod, a semi-cylindrical frangible coupling sleeve connects an upper valve rod section to a lower valve rod section in about the same horizontal plane as the upper and lower standpipes are coupled to each other. Then when the upper standpipe is broken away from the lower standpipe, the frangible coupling sleeve will also break, allowing separation of the upper valve rod section from the lower valve rod section without substantial danger of damage to the hydrant. To prevent misalignment of the upper rod section with the lower rod section in the event of the accidental rupture of the frangible coupling sleeve, a semi-cylindrical coupling sleeve is bolted to the bottom portion of the upper rod section opposite the frangible coupling sleeve and is provided with a downwardly opening slot to ride on a stud extending outwardly through the upper portion of the lower valve rod section from its position where it holds the frangible coupling sleeve in fixed relationship to that upper portion of the lower valve rod section.</p> |
