Abstract:
The telescoping pop-up sprinkler includes a telescoping piston assembly that allows the piston assembly of the pop-up to extend upwards at a greater height than the length of the pop-up sprinkler body. The telescoping pop-up sprinkler has a main body with a piston assembly that includes two or more pistons that engage internally with one another, with stops provided at one end of each piston to limit the stroke of each piston. Multiple internal seals are provided to prevent the bypassing of water around the outer diameter of each piston.

Description:
RELATED APPLICATIONS 
     This application is a continuation of Ser. No. 11/193,289, filed Jul. 29, 2005, now U.S. Pat. No. 7,500,620. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to irrigation sprinklers or sprayheads, and more particularly relates to a telescoping pop-up sprinkler assembly for extending the height of a sprinkler. 
     2. General Background and State of the Art 
     An advantage of a pop-up sprinkler over a permanently upright sprinkler extending above the ground is that the entire sprinkler remains buried in the ground until the pop-up sprinkler is activated by water pressure, when the piston is pushed above ground level to spray water. By remaining buried in the ground until activated, damage to the sprinkler can be prevented or minimized that might otherwise occur if the sprinkler were permanently in an upright position above ground level. 
     Pop-up irrigation sprinklers are commonly manufactured in heights from two to twelve inches. Such pop-up sprinklers usually include a cap, a seal, a piston, a spring, a ratchet and a body. The body is usually longer than the height of the pop-up sprinkler, to allow sufficient space in the body for the spring, seal and end of the piston. For example, a two inch pop body would be four inches long, to allow two inches of piston extension, leaving two inches of piston in the body to support the piston from a side thrust when a half spray nozzle is used, and leaving space for the spring in the compression stage. As heights change in order to achieve adequate spray patterns over taller grasses or shrubbery, tall sprinklers are used. Usually the piston length increases in direct relation the increase in the length of the body of the sprinkler. With a six inch pop-up sprinkler, the sprinkler body is typically about nine inches long, to account for the additional leverage created by the increased height of the pop-up piston. In a twelve pop-up sprinkler, the sprinkler body is typically about fifteen inches long. 
     It should be readily apparent that for installation of a pop-up sprinkler the hole or trench that has to be dug would need to exceed the total length of the body of the pop-up sprinkler, as well as the height of the connector used to attach the body of the pop-up sprinkler to a water supply pipe, plus the diameter of the water supply pipe. For example, for installation of a two inch pop-up sprinkler, a trench would need to be a minimum of six inches deep if not up to ten inches deep, and for installation of a twelve inch pop-up sprinkler, the trench may be up to eighteen inches or twenty-four inches deep. 
     It would be desirable to provide a pop-up sprinkler that telescopes to extend the height of the sprinkler, to reduce the depth of trenches needed for installation of the pop-up sprinkler, and to minimize installation time and expense. It would also be desirable to provide a pop-up sprinkler with improved seals for the telescoping piston assembly. The present invention satisfies these and other needs. 
     INVENTION SUMMARY 
     Briefly, and in general terms, the invention provides for a telescoping pop-up sprinkler with a telescoping piston assembly that allows the piston assembly of the pop-up to extend upwards at a greater height than the length of the pop-up sprinkler body. The telescoping pop-up sprinkler has a main body with a piston assembly that includes two or more pistons that engage internally with one another, with stops provided at one end of each piston to limit the stroke of each piston. Multiple internal seals are provided to prevent the bypassing of water around the outer diameter of each piston. 
     The telescoping pop-up sprinkler is designed so that the tubular main body is longer than the height of the pop-up sprinkler, to allow sufficient space in the body for the spring, seal and the primary and secondary pistons. For example, the telescoping pop-up sprinkler would typically provide a four inch body for a seven inch extension of the piston assembly, or a six inch body for a thirteen inch extension of the piston assembly. In the latter example, a trench would only have to be dug ten inches to twelve inches deep to install a pop-up sprinkler that would extend thirteen inches, in comparison to an ordinary twelve inch pop-up sprinkler that would require a trench from eighteen to twenty-four inches in depth. In addition, the telescoping pop-up sprinkler of the invention will allow a pop-up sprinkler with a twelve inch body to be able to extend eighteen inches or more, and still keep the depth of the trench at eighteen to twenty-four inches. 
     The present invention accordingly provides for a telescoping pop-up sprinkler head including a tubular main body and a telescoping piston assembly disposed in the tubular main body. The telescoping piston assembly includes a primary piston and a secondary piston engaged together in telescoping, sliding relationship. The primary piston has a tubular body with a retaining flange at a lower end, and a primary spring disposed over the tubular body of the primary piston above the retaining flange of the tubular body of the primary piston. The upper surface of the retaining flange includes a plurality of detents, and a ratchet member that interacts with the plurality of detents is disposed over the tubular body of the primary piston at the lower end of the primary piston between the primary spring and the retaining flange. The ratchet member engages with the plurality of internal ribs in the tubular main body. A cap is disposed on the upper end of the tubular main body, retaining a primary seal disposed over the tubular body of the primary piston in the tubular main body to seal the tubular main body, cap and primary piston from leaking water. The primary seal is currently a chevron type of seal, having an inner sealing flap that is activated by external water pressure. A spring retainer is disposed between the primary seal and the primary spring to prevent pressure from the primary spring against the primary seal from distorting the primary seal. The spring retainer also has slots in it to allow water pressure to activate the chevron seal during operation of the sprinkler. 
     The secondary piston has a tubular body with a lower retaining flange having a plurality of radial slots adapted to interfit with the plurality of internal ribs of the tubular body of the primary piston. The radial slots in the lower retaining flange correspond to and engage the plurality of internal ribs in the primary piston, to keep the secondary piston from rotating, and allow water to pass between primary and secondary pistons to activate the chevron seal on the secondary seal. A secondary chevron seal is disposed over the tubular body of the secondary piston within the tubular body of the primary piston to seal the primary piston and the secondary piston from leaking water, commonly called “flow by.” A seal retainer is threadably engaged in the upper end of the tubular body of the primary piston to holds the secondary seal in place in the primary piston. The tubular body of the primary piston also includes an annular internal stop for retaining the secondary seal between the annular internal stop and the seal retainer. The annular internal stop in the primary piston is slotted to let water pressure through to activate the chevron seal on the secondary seal to activate it against the secondary piston to stop flow by. A secondary spring is disposed over the tubular body of the secondary piston between the retaining flange of the tubular body of the secondary piston and the annular internal stop of the tubular body of the primary piston. 
     Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments in conjunction with the accompanying drawings, which illustrate, by way of example, the operation of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of the telescoping pop-up sprinkler according to the present invention. 
         FIG. 2  is a plan view of a primary chevron seal of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the primary chevron seal taken along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is an elevational view of the telescoping pop-up sprinkler of  FIG. 1  in an unextended configuration. 
         FIG. 5  is a cross-sectional view of the telescoping pop-up sprinkler of  FIG. 1  in an unextended configuration. 
         FIG. 6  is an elevational view of the telescoping pop-up sprinkler of  FIG. 1  showing the secondary piston in an extended configuration. 
         FIG. 7  is a cross-sectional view of the telescoping pop-up sprinkler of  FIG. 1  showing the secondary piston in an extended configuration. 
         FIG. 8  is an elevational view of the telescoping pop-up sprinkler of  FIG. 1  showing the primary and secondary pistons in an extended configuration. 
         FIG. 9  is a cross-sectional view of the telescoping pop-up sprinkler of  FIG. 1  showing the primary and secondary pistons in an extended configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, which are provided for purposes of illustration and by way of example, the present invention provides for a telescoping pop-up sprinkler  10  connectable with a source of pressurized fluid, such as a water supply pipe (not shown). The telescoping pop-up sprinkler includes a tubular main body  12  having a longitudinal axis  14 , an upper end  16 , and a lower connector end  18 . The upper end of the tubular main body has external threads  20  for receiving a cap  21 , and the lower connector end is adapted to be connected to the source of pressurized fluid. The lower connector end may have internal threads  19 , for connection to a water supply pipe, for example. The tubular main body has an inner surface defining a plurality of internal ribs  22  extending longitudinally in the tubular main body. 
     The telescoping pop-up sprinkler also includes a telescoping piston assembly  24  disposed in the tubular main body. The telescoping piston assembly includes a primary piston  26  and a secondary piston  28 . The primary piston has a tubular body  30  with an upper end  32  and a lower end  34 . The upper end is currently preferably internally threaded  36 , and the lower end includes a retaining flange  38  with a plurality of radial slots  39  to allow water to pass up to activate the primary seal, as will be further explained below. A plurality of internal ribs  40  are preferably formed on the inner surface of the tubular body of the primary piston and extending longitudinally in the tubular body of the primary piston. A primary spring  42  is disposed over the tubular body of the primary piston between the retaining flange of the tubular body of the primary piston and the spring retainer  44 , described further below. In a currently preferred aspect, the upper surface  46  of the retaining flange includes a plurality of detents  48 , and a ratchet member  50  that interacts with the detents of the retaining flange is disposed over the tubular body of the primary piston at the lower end of the primary piston, between the primary spring and the retaining flange. The ratchet member also engages with the plurality of internal ribs in the main body. 
     A primary seal  52  having an annular body  54  is disposed over the upper end of the tubular body of the primary piston, to seal the body, cap and primary piston from leaking water. In a currently preferred aspect, the primary seal is a chevron type of seal having a chevron or V-shaped groove  58  extending around the under side of the annular body of the seal, forming an inner flap  60  that operates as a pressure activated seal when the seal is pressurized by the pressurized fluid, such as water. The primary seal is currently preferably formed of a relatively pliable sealing material, such as a soft polytetrafluoroethylene seal material, available under the trade name Teflon from DuPont. 
     The spring retainer  44  has an annular body  62 , with an opening  64  formed in the annular body extending through the spring retainer from the upper side to the lower side with a clearance sufficiently large to advantageously allow water pressure to activate the chevron seal during operation of the sprinkler. The spring retainer is disposed between the primary seal and the primary spring primarily to retain the primary spring when the sprinkler is assembled, and to prevent distortion of the primary seal by pressure from the primary spring. The cap is threadedly engaged on the upper end of the tubular main body, retaining the primary seal in the tubular main body. The cap has internal threads  68  engaging the external threads of the upper end of the tubular main body. 
     The secondary piston has a tubular body  70  with an upper end  72  and a lower end  74 . The upper end currently preferably has external or internal threads  76  for receiving a sprinkler head or nozzle  77  with corresponding internal or external threads, illustrated in  FIG. 1 , and the lower end includes a retaining flange  78  with a plurality of radial slots  80  adapted to interfit with the plurality of internal ribs of the tubular body of the primary piston to keep the secondary piston from rotating. The lower end includes a longitudinal slot  84 . A secondary seal  86  is disposed over the tubular body of the secondary piston within the tubular body of the primary piston to seal the primary piston and the secondary piston from leaking water. In a currently preferred aspect, the secondary seal is a chevron type of seal, as described above. The radial slots in the retaining flange of the secondary piston also allow water to pass between the primary and secondary pistons to activate the chevron seal on the secondary seal. A seal retainer  90  is threadably engaged in the upper end of the tubular body of the primary piston to hold the secondary seal in place in the primary piston. The upper flange  91  on the seal retainer  90  preferably is of a sufficiently large diameter to hold the piston assembly together when the sprinkler is assembled, and the flange sits on top of the cap  21  when the sprinkler is assembled, as shown in  FIGS. 4 ,  5  and  7 . When a sprinkler head or nozzle  77  is attached to piston  72  and the cap  21  is unscrewed from the body  12 , the entire nozzle and piston assembly can be removed from the body  12 , and stays intact. The tubular body of the primary piston includes an annular internal stop  92  for retaining the secondary seal between the annular internal stop and the seal retainer. In a currently preferred aspect, the annular internal stop in the primary piston includes an opening  94  with a sufficiently large clearance to let water pressure through to activate the “chevron” on the secondary seal to activate the secondary seal against the secondary piston to stop flow by. A secondary spring  96  is disposed over the tubular body of the secondary piston between the retaining flange of the tubular body of the secondary piston and the annular internal stop of the tubular body of the primary piston. 
     It should be recognized that the foregoing description relates primarily to dual stage telescoping piston. However, by enlarging the tubular main body in circumference, or installing a smaller third piston, the telescoping pop-up sprinkler can be made in multiple stages, increasing the height of the piston above the cap or ground level to even greater heights in relationship to the height of the body and the depth of the trench necessary to install the pop-up spray head to keep the telescoping pop-up sprinkler at ground level in the unextended position. 
     It will be apparent from the foregoing that, while particular forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.