Metal working – Means to assemble or disassemble – By rotation of work part
Reexamination Certificate
2002-06-26
2004-09-28
Watson, Robert C. (Department: 3723)
Metal working
Means to assemble or disassemble
By rotation of work part
Reexamination Certificate
active
06796013
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to tools for installing and repairing pop-up sprinkler units. In particular, the present invention relates to the installation, removal, repair, and/or replacement of the outer casing or the inner tubular housing of a pop-up sprinkler unit.
Current methods for watering lawns and gardens include underground irrigation systems with pop-up sprinkler units. Pop-up sprinkler units are particularly convenient because they are embedded in the ground when not in use. A pop-up rotary sprinkler unit typically includes a cylindrical outer casing, a cylindrical inner tubular housing concentrically mounted in the outer casing, and a threadably mounted retaining cap which secures the inner tubular housing in the outer casing. The retaining cap is detachably mounted by threads onto the outer casing.
The pop-up sprinkler unit is connected to a pressurized water supply line with a threaded riser located at the base of the sprinkler unit. The inner tubular housing extends upwardly from the outer casing when in operation due to hydraulic pressure provided when the pressurized water supply line is charged. The threadably mounted retaining cap holds the outer casing in relation to the inner tubular housing to allow the inner tubular housing to pop-up while being retained within the outer casing when the irrigation system is charged. The threadably mounted retaining cap is usually designed with numerous outwardly projecting threadably mounted retaining caps provided in order to gain purchase on the sprinkler unit. For examples of pop-up sprinklers of this general type, see U.S. Pat. Nos. 5,423,486 and 4,625,914.
At various times it may be desirable to remove either portions of the sprinkler unit individually or in combination, or the sprinkler unit in its entirety. Frequently, the seal between the inner tubular housing and the threadably mounted retaining cap becomes worn and the sprinkler leaks when the inner tubular housing is upwardly extended. It is desirable to replace the seal without having to remove the entire sprinkler unit. Removing the inner tubular housing while retaining the outer casing in the proper orientation on the threaded riser at its base involves unscrewing the threadably mounted retaining cap. Unfortunately, the tight friction fit between the threadably mounted retaining cap and the outer casing, as well as dirt, sand, organic debris, and soil on the threads of the outer casing, often result in the entire sprinkler unit rotating on the threaded riser. This results in the misalignment of the sprinkler, or as is often the case, the unintentional removal of the entire sprinkler unit.
Where grass has grown tightly around the sprinkler unit or where dirt has become compacted around the unit, it is often necessary to expand the hole in which the sprinkler unit is retained so that the sprinkler unit can be reattached to the threaded riser at the base. This damages the grass on the lawn, leaving it unsightly and necessitating sodding, seeding, and/or fertilization to induce re-growth of grass. Further, this process is extremely time consuming. Thus, there is a current need for a device to remove the threadably mounted retaining cap without turning or removing the outer casing.
Another problem encountered when initially installing sprinkler units, or when removing either the inner tubular housing or the entire sprinkler unit from the water supply for repair, is that loose soil, debris and rocks fall down into the piping system to contaminate and plug not only the piping system at that particular head but other inner tubular housings and sprinkler heads on the line. To ensure no loose debris or rocks remain in the piping system, the piping system is often purged before installing (or replacing) the sprinkler unit or the outer casing. Purging involves turning on the water system to flush debris from the piping, then shutting off the water supply and installing a sprinkler unit over the threaded riser connected to the irrigation system.
Purging is a time-consuming and messy process generally requiring two service people to manipulate the water supply and sprinkler, thereby making installment or repair of pop-up sprinkler units expensive. Purging is performed at the time of installation of the irrigation system, or when individual sprinkler units are replaced or serviced.
During initial installation, all sprinklers on a “line” must be installed and then the sprinklers individually removed with the system being turned on and then off between removal of each sprinkler on a line to be sure to flush all debris that has accumulated at that sprinkler has been removed. This must be done in a particular order starting with the sprinkler closest to the valve providing water to the system and proceeding to the furthest point in the system. In the case of a circle system where the zone is connected at both ends, the sprinklers must be individually removed starting at the end of the circle closest to the supply valve and moving from both sides to the sprinkler furthest away.
Purging is also a difficult problem when repairing or removing individual sprinkler units once a system has been installed. If the sprinkler unit is removed from the ground, debris including dirt, soil, sand, and grass fall into the hole from which the sprinkler is removed. These are very narrow and deep holes, making it extremely difficult to reattach the sprinkler unit without getting debris into the line and subsequently clogging the reinstalled sprinkler unit. Thus, before the sprinkler can be replaced, the irrigation line must be purged. Unfortunately, this fills the hole with water and results in additional debris in the line. It is extremely difficult to replace a sprinkler without contaminating the line and sprinkler unit with debris.
There are tools available to aid in removing pop-up sprinkler heads and inner tubular housings. One such tool compresses the ground around the sprinkler head to tightly grip the outer casing of the head so that it may be threadedly disengaged from the pressurized water supply line. See, for example, U.S. Pat. No. 4,788,894. Such tools, however, continue to damage and mar the lawn and allow loose soil fragments and rocks to contaminate the irrigation system. Other tools include a handheld tool for lifting an inner tubular housing to an extended position, where a sleeve is arranged for mounting and engaging the top of the inner tubular housing to facilitate lifting of the inner tubular housing. See U.S. Pat. No. 4,866,801. This tool does not effectively remove the inner tubular housing from the outer casing. U.S. Pat. Nos. 3,977,063 and 3,731,364 set forth further examples of sprinkler tool structures arranged for the maintenance of sprinkler systems. These tools are generally complex and impractical.
Therefore, there continues to be a need for new and improved tools to remove outer casings, inner tubular housings, and threadably mounted retaining caps of pop-up sprinkler units. The present invention overcomes these problems and disadvantages by providing tools for removing and installing the outer casing, inner tubular housing, and threadably mounted retaining cap of a pop-up sprinkler unit. The method of using the tools is simple and efficient while the tools themselves are easily manufactured.
BRIEF SUMMARY OF THE INVENTION
The present invention provides tools for installing, maintaining and/or repairing sprinkler systems. In a preferred embodiment, the tools of the subject invention are specifically adapted for use with in-ground sprinkler systems with sprinkler units having an outer casing, an inner tubular housing (concentrically mounted inside the outer casing), and a threadably mounted retaining cap. When the system is activated under hydraulic pressure, the inner tubular housing pops up out of the outer casing which remains firmly stationed in the ground. Advantageously, the tools of the subject invention can be used to easily and conveniently install, remove, and/or replace the inner tubular housings, the outer casings, and t
Matthew Gary
Melker Richard J.
Saliwanchik Lloyd & Saliwanchik
Watson Robert C.
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