Abstract:
A hand manipulatable tool for removing and replacing sprinkler heads threadably connected to an underground watering system employs a straight metal pipe component having outwardly flared portions at both extremities adapted to grip the sprinkler heads. A straight handle rod interactive with the pipe component facilitates unscrewing and lifting of the gripped sprinkler head.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the servicing of underground watering systems, and more particularly concerns a hand tool for the removal and replacement of sprinkler head components of underground systems for lawn watering. 
     2. Description of the Prior Art 
     Underground watering systems are commonly utilized for accurately and controllably spraying water onto grass lawns. Such systems are comprised of plastic supply pipes arranged as a substantially horizontal network installed about one to two feet below the lawn. At strategic intervals and locations, riser pipes are vertically emergent from the supply pipes, and terminate in male threaded extremities. 
     A sprinkler head is attached to the upper extremity of each riser pipe. The sprinkler head is comprised of a cylindrical housing, generally of plastic construction, having a centered bottom female threaded collar aperture adapted to screw onto the threaded upper extremity of the riser pipe. A removable spring-actuated internal cartridge is seated within the cylindrical housing, and is secured therein by external threading on the upper extremity of the housing. The upper extremity of said cartridge has a circular rim having peripheral apertures for the radial distribution of water. Said rim is operationally positioned at an elevation adjacent the root line of the grass. 
     In the course of foot and/or vehicle traffic upon the lawn, and mowing maintenance, sprinkler heads become damaged, and often require replacement. U.S. Pat. No. 4,788,894 to Mitschele discloses a hand tool for removing sprinkler heads from underground watering systems. Mitschele&#39;s tool is comprised of a hollow encasement dimensioned to embrace the entire length of the sprinkler head while also engulfing surrounding soil. The encasement containing the sprinkler head is then twisted, causing the engulfed soil to compressively grip the housing member of the sprinkler head. Further twisting causes the sprinkler head to unthreadably detach from the underlying riser pipe to permit upward removal. Such action leaves an empty hole in the ground. 
     Although the Mitschele tool may perform properly with permissive soil texture and moisture, removal of the compressed soil from the encasement is difficult. Even more difficult is the return of the removed soil to the hole to facilitate proper seating of a replacement sprinkler head while preventing soil from entering the open upper extremity of the riser pipe. Also, Mitschele makes no provision for accurately aligning a replacement sprinkler head for threadable engagement with the upper extremity of the riser pipe. 
     Accordingly, it is an object of the present invention to provide a tool for the removal and replacement of a sprinkler head component of an underground watering system. 
     It is another object of this invention to provide a tool as in the foregoing object which can be hand-manipulated. 
     It is a further object of the present invention to provide a tool of the aforesaid nature which does not require removal of surrounding soil to achieve removal of a sprinkler head. 
     It is an additional object of this invention to provide a tool of the aforesaid nature having means for aligning a replacement sprinkler head for proper threaded installation upon an underlying riser pipe. 
     It is a still further object of the present invention to provide a tool of the aforesaid nature adaptable to use with sprinkler heads of various diameter. 
     It is yet another object of this invention to provide a tool of the aforesaid nature which is easily maintainable, durably constructed and amenable to low cost manufacture. 
     These objects and other objects and advantages of the invention will be apparent from the following description. 
     SUMMARY OF THE INVENTION 
     The above and other beneficial objects and advantages are accomplished in accordance with the present invention by a hand manipulatable tool for removing and replacing the sprinkler head of an underground watering system, said sprinkler head having an uppermost circular top rim, said tool comprising:
     1) a metal pipe component extending on a straight center axis between large and small open gripping extremities, and having at least one pair of diametrically opposed apertures, each gripping extremity having an outwardly flared portion adapted to engage variously sized circular top rims of sprinkler heads, said engagement being sufficiently strong to permit rotation and lifting of said sprinkler head, and   2) a straight handle rod adapted to penetrate said apertures to facilitate rotation of said pipe about said axis and lifting of said tool with an engaged sprinkler head.   

    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing forming a part of this specification and in which similar numerals of reference indicate corresponding parts in all the figures of the drawing: 
         FIG. 1  is a side view of an embodiment of the tool of the present invention shown in operative association with a sprinkler head of an underground watering system. 
         FIG. 2  is an enlarged vertical sectional view of the embodiment of  FIG. 1 . 
         FIG. 3  is an enlarged bottom view of the embodiment of  FIG. 2 . 
         FIG. 4  is an enlarged vertical sectional side view of the large gripping extremity of the embodiment of  FIG. 2 . 
         FIG. 5  is a sectional side view illustrating a secondary mode of function of the tool of the present invention. 
         FIG. 6  is an exploded side view of the sprinkler head of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to  FIGS. 1-5 , an embodiment of the sprinkler head removing tool  10  of this invention is shown comprised of a metal pipe component  11  of monolithic construction extending upon a straight center axis  12  between large and small open gripping extremities  13  and  14 , respectively. At least one pair of diametrically opposed apertures  15  slidably accommodate a straight rod handle  16 . 
     In the illustrated embodiment, pipe  11  has an overall length between 27 and 32 inches, and an inside diameter of about 2″ inches. Rod handle  16  has a diameter of about ½″ and a length of 12 to 14 inches. Both the large and small gripping extremities have outwardly flared, substantially conically shaped portions  17  and  22  respectively, terminating in circular perimeter edges  41  and  42 , respectively. Such flared structure is the result of high force insertion of a substantially conical shaping mandrel into the extremities of pipe  11 , causing controlled expansion of said perimeter edges. The interior surface  46  of each flared portion preferably contains gripping features capable of frictionally securing the circular plastic upper rim  24  of a typical sprinkler head  25 . 
     The present invention is based in part upon the discovery that effective gripping features can be in the form of discontinuities in the otherwise symmetrical circular cross section of the flared portions. Preferred discontinuities are in the form of axially elongated intrusions  45  integral with the interior surface  46  of the flared portions and projecting inwardly toward said axis by an amount equal to about 1%-2% of said inside circular diameter. At least two such intrusions are preferred in spaced apart relationship. In a particularly preferred embodiment, a first intrusion, having a width of about 5% of the circumference of the circular cross section of the flared portion, is spaced apart by about 3% of said circumference from a second intrusion having a shape and dimensions comparable to said first intrusion. In preferred embodiments, the number and spacing of said intrusions is such as to occupy about 90° of the periphery of the flared portion. Said intrusions are produced by axially elongated flattened regions in a conically shaped mandrel which is forced into each extremity of pipe  11  for the purpose of producing said flared portions. 
     The conically shaped portion  17  of large gripping extremity  13  extends axially about 3.7 inches. Its associated circular perimeter edge  41  has an inside diameter of about 2⅜ inches, thereby defining a convergence angle A of about 5° relative to axis  12 . Small gripping extremity  14  extends between circular perimeter edge  42 , having an inside diameter of about 2⅛ inches, and an annular crimp depression  21  having been formed in a compression swage reduction operation. The distance of separation between edge  42  and depression  21  is about 3.7 inches, and defines a convergence angle A of about 6°. The overall effect of the two gripping extremities is to enable the handling of sprinkler heads whose circular rim diameters  24  range from 1¾″ and 2⅜″. The different convergence angles, which may range between 4° and 7°, provide versatility of gripping effectiveness. It has further been found that the gripping effectiveness is better when the tool is fabricated of iron rather than plastic. 
     In operation, as shown in  FIG. 1 , the tool of the present invention is vertically placed upon the circular rim  24  of sprinkler head  25  confined within hole  26  in the soil  27 . Said circular rim is generally positioned at the root level of the lawn grass  28 . A female threaded collar  29  centered within the bottom of said sprinkler head threadably engages the male threaded upper extremity  30  of riser pipe  31  emergent from supply line  32 . With downward force, the gripping extremity secures the circular rim  24 , and permits unthreading and lifting motions to remove the sprinkler head from hole  26  without disturbing the contour of the hole. 
     A replacement sprinkler head can generally be installed simply by inserting it into the hole and twisting. However, in many instances there may be difficulties in precisely aligning the female threaded collar  29  on the bottom of the sprinkler head with the male threaded upper extremity  30  of the riser pipe. In such instances, a typical sprinkler head, constructed as shown in  FIG. 6 , is dismantled by unthreading and removing the center cartridge  34  from housing component  35 . Then, as shown in  FIG. 5 , rod handle  16 , removed from pipe  11 , is inserted downwardly through said housing component and into riser pipe  31 . Such action achieves the necessary alignment and securement of the involved threaded members. It also prevents entrance of dirt into the riser pipe. The rod handle is then removed and center cartridge  34  is re-threaded onto housing component  35 . The aligned and intact sprinkler head is then twisted using the tool of this invention to complete the installation. 
     While particular examples of the present invention have been shown and described, it is apparent that changes and modifications may be made therein without departing from the invention in its broadest aspects. The aim of the appended claims, therefore, is to cover all such changes and modifications as fall within the true spirit and scope of the invention.