Abstract:
The present disclosure relates to a jet pump tail cone insert for a jet pump. The jet pump tail cone insert comprises a cap, a body and an end member. The end member has a plurality of projections configured to matingly receive a plurality of forks of the body. When connected together, the body and the end member have a plurality of receivers configured to receive stator vanes of a bearing hub of the jet pump. The body and the end member are configured to be proximate the stator vanes. The cap is configured to matingly couple to the body. The jet pump tail cone insert encompasses a portion of the bearing hub of the jet pump. The jet pump tail cone insert occupies within the bearing hub thereby increasing a flow rate of water through the jet pump.

Description:
PRIORITY STATEMENT 
       [0001]    This application is a continuation of and claims priority to U.S. application Ser. No. 11/365,786, entitled “Jet Pump Tail Cone Insert” filed on Feb. 28, 2006, which claims priority to U.S. Provisional Application No. 60/667,225, entitled “Jet Pump Tail Cone Insert” filed on Mar. 31, 2005, the disclosures of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to jet pumps, and more particularly, it relates to increasing the efficiency of jet pumps. 
         [0003]    Personal water crafts, such as JET SKIS® and the like, are known in the art. Personal water crafts utilize an engine that drives an impeller to transfer water through the drive system, thus propelling the personal water crafts. Standard personal water crafts can travel at speeds of about 35 miles per hour (mph), while high performance personal water crafts can travel at speeds of about 80 mph. However, high performance personal water crafts and their accompanying parts are expensive. Standard jet pumps utilized in standard personal water crafts are inefficient, transferring too much water through a large opening, thus minimizing the performance and speed of the personal water crafts. 
         [0004]    In the converse, frequently the jet pump becomes “unloaded” because of the absence of available water to maintain the loaded state of the jet pump. This results in the jet pump being inefficient and minimizes performance. 
         [0005]    What is needed in the art is a device that can increase the efficiency of a standard jet pump without redesigning the existing jet pump. 
       SUMMARY 
       [0006]    The following presents a simplified summary of the present invention in order to provide a basic understanding of some aspects of the present invention. This summary is not an extensive overview of the present invention. It is not intended to identify key or critical elements of the present invention or to delineate the scope of the present invention. Its sole purpose is to present some concepts of the present invention in a simplified form as a prelude to the more detailed description that is presented herein. 
         [0007]    The present disclosure relates to a jet pump tail cone insert for a jet pump. The jet pump tail cone insert comprises a cap, a body and an end member. The end member has a plurality of projections configured to matingly receive a plurality of forks of the body. When connected together, the body and the end member have a plurality of receivers configured to receive stator vanes of a bearing hub of the jet pump. The body and the end member are configured to be proximate the stator vanes. The cap is configured to matingly couple to the body. The jet pump tail cone insert encompasses a portion of the bearing hub of the jet pump. The jet pump tail cone insert occupies within the bearing hub thereby increasing a flow rate of water through the jet pump. 
         [0008]    The disclosure is directed toward a method of decreasing a flow area within a jet pump. The method comprises disposing a jet pump tail cone insert encompassing a portion of a bearing hub of the jet pump. The jet pump tail cone insert includes an end member having an interior and an exterior, an upper portion and a lower portion, a plurality of projections configured to matingly receive a plurality of forks, and a plurality of receivers configured to receive at least one stator vane of the bearing hub. The jet pump tail cone insert includes a body having an interior and an exterior, an upper portion and a lower portion, said plurality of forks configured to matingly attach to the plurality of projections, and a plurality of receivers configured to receive the at least one stator vane of the jet pump. The body is configured to be physically positioned about the stator vanes and the lower portion of the body is configured to matingly couple to the upper portion of the end member. The jet pump tail cone insert includes a cap having an interior and an exterior and an upper portion and a lower portion. The lower portion of the cap is configured to matingly couple to the upper portion of the body. The method the jet pump tail cone insert occupies space proximate the bearing hub thereby increasing a flow rate of water through the jet pump. The flow rate of the water increases the internal pressure within the jet pump. 
         [0009]    The disclosure is directed toward a jet pump tail cone insert for a jet pump. The jet pump tail cone insert comprises an end member having an interior and an exterior, an upper portion and a lower portion, a plurality of projections configured to matingly receive a plurality of forks, and a plurality of receivers configured to receive at least one stator vane of a bearing hub of the jet pump. The jet pump tail cone insert also comprises a body having an interior and an exterior, an upper portion and a lower portion, the plurality of forks configured to matingly attach to the plurality of projections of the end member, and a plurality of receivers configured to receive the at least one stator vane of the bearing hub. The body is configured to be proximate the at least one stator vane, with the lower portion of the body configured to matingly couple to the upper portion of the end member. The jet pump tail cone insert also comprises a cap having an interior and an exterior and an upper portion and a lower portion, in which the lower portion of the cap is configured to matingly couple to the upper portion of the body. The jet pump tail cone insert encompasses a portion of the bearing hub of the jet pump. 
         [0010]    The jet pump tail cone insert further comprises at least one fastener disposed in at least one groove in the cap. The at least one fastener extends through the cap, the body, and into at least one coupling in the end member. The fastener is configured to securely couple the cap to the body and the body to the end member. 
         [0011]    The jet pump tail cone insert further comprises at least one shim coupled to the lower portion of the cap. In one embodiment, the cap comprises two pieces; a base portion comprising the lower portion and a tip portion comprising the upper portion. The tip portion can be interchangeable. The cap, the body and the end member are attached together with an interior locking mechanism. 
         [0012]    The present invention discloses that the number of forks, the number of projections, and the number of receivers is dependent upon the number of stator vanes in the jet pump. The jet pump tail cone insert occupies space proximate the bearing hub thereby increasing a flow rate of water through the jet pump. 
         [0013]    The disclosure is directed toward a method of installing a jet pump tail cone insert in a jet pump. The method comprises disposing an end member proximate at least one stator vane of a bearing hub opposite an exterior side of an impeller of the jet pump. The end member has an interior and an exterior, an upper portion and a lower portion, a plurality of projections configured to matingly receive a plurality of forks, and a plurality of receivers configured to receive the at least one stator vane. The method further comprises matingly coupling a body to the upper portion of the end member. The body has an interior and an exterior, an upper portion and a lower portion, the plurality of forks configured to matingly attach to the plurality of projections of the end member, and the plurality of receivers configured to receive the at least one stator vane of the bearing hub. The body is configured to be physically positioned proximate the at least one stator vane. The method also comprises matingly coupling a cap of the jet pump tail cone insert to the upper portion of the body. The cap having an interior and an exterior and an upper portion and a lower portion. 
         [0014]    The method further comprises disposing at least one fastener to extend through the cap, through the body, and into at least one coupling in the end member. The fastener is configured to securely couple the cap to the body and the body to the end member. 
         [0015]    The method also discloses disposing at least one shim to the lower portion of the cap. The can comprise two pieces; a base portion comprising the lower portion and a tip portion comprising the upper portion. The tip portion is interchangeable. 
         [0016]    The method also discloses attaching the cap, the body, and the end member together with at least one interior locking mechanism. 
         [0017]    The method also discloses the number of forks, the number of projections, and the number of receivers is dependent upon the number of stator vanes in the bearing hub. The jet pump tail cone insert occupies space proximate the bearing hub thereby increasing a flow rate of water through the jet pump, wherein the flow rate of the water increases the internal pressure within the jet pump. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES  
         [0018]    Referring now to the figures, wherein like elements are numbered alike: 
           [0019]      FIG. 1  is a perspective view of an exemplary embodiment of a jet pump tail cone insert; 
           [0020]      FIG. 2  is a perspective exploded view of elements of an exemplary embodiment of a jet pump tail cone insert as positioned to be installed in a jet pump; 
           [0021]      FIG. 3  is a side exploded view of elements of an exemplary embodiment of a jet pump tail cone insert as positioned to be installed in a jet pump; 
           [0022]      FIG. 4  is a cross section of the exploded view of elements of an exemplary embodiment of a jet pump tail cone insert as positioned to be installed in a jet pump taken along line A of  FIG. 3 ; 
           [0023]      FIG. 5  is a perspective exploded view of elements of an exemplary embodiment of a jet pump tail cone insert; 
           [0024]      FIG. 6  is a perspective rear view of an exemplary embodiment of a jet pump tail cone insert installed in a jet pump; 
           [0025]      FIG. 7  is a perspective top view of an exemplary embodiment of a jet pump tail cone insert installed in a jet pump; and 
           [0026]      FIG. 8  is a cross section of an exemplary embodiment of a jet pump tail cone insert installed in a jet pump taken along line B of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION  
       [0027]    Persons of ordinary skill in the art will realize that the following disclosure is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. 
         [0028]    In a conventional craft using a conventional jet pump, water enters the suction inlet (or intake cavity) of the craft and is forced towards the jet pump. The engine turns a shaft that operates an impeller that pulls water in and forces water towards the rear of the craft. This flow of water propels the craft through the water and provides a means to steer the craft. In the jet pump, the water flows through the impeller into the next cavity (i.e., the bearing hub). The water entering the next cavity is turbulent. In order to propel and steer the craft, the water must be directed and “straightened.” Conventional jet pumps have stator vanes to straighten the flow of water. The water is forced through the stator vanes and out of the craft through the exit nozzle. 
         [0029]    The present invention is a jet pump tail cone insert. The intention of the jet pump tail cone insert is to enlarge the center diameter of the jet pump bearing hub. This increases pump pressure which results in better efficiency of the pump. The method of installation includes a three-piece design that is retained by the original mounting holes for the bearing end cone. The jet pump tail cone insert is completely removable. The dimensions of the jet pump tail cone insert are specific to each jet pump model. The diameter of the insert increases if the inside diameter of the pump increases. With an increase of horsepower in the motors, the stock pump becomes inefficient which makes a pump modification necessary. The jet pump tail cone insert part allows the customer to utilize the stock pump rather than replacing it with an expensive after-market jet pump. 
         [0030]    The present invention transforms the inefficient original equipment manufactured (OEM) pump into a high performance race pump. The hub diameter of the OEM pump has been increased, which creates an increase in pump pressure keeping the pump “loaded” in rough water conditions. The increased efficiency adds amazing acceleration, improved handling and top speed. 
         [0031]    Referring to  FIGS. 1 ,  2 ,  3 , and  4 , an exemplary jet pump tail cone insert  10  is illustrated assembled ( FIG. 1 ) and disassembled ( FIGS. 2 ,  3 ,  4 ). The jet pump tail cone insert  10  is installed within the jet pump  46 , as will be illustrated and described further herein. Specifically,  FIG. 2  illustrates an exploded perspective view of the jet pump tail cone insert  10  and jet pump  46  disassembled.  FIG. 3  is a side view perspective view of the jet pump tail cone insert  10  and jet pump  46  disassembled.  FIG. 4  is a cross section of the jet pump tail cone insert  10  and jet pump  46  disassembled taken along line A of  FIG. 3 . 
         [0032]    The jet pump tail cone insert  10  includes a cap  12 , a body  14  and an end member  16 . In one embodiment, the cap  12  has an interior portion  18  opposite an exterior portion  20 . The cap  12  can be hollow or solid. Disposed on the exterior portion  20  are grooves  22  having passages  24  that are configured to receive a fastener (See  FIG. 5 , numerals  86  and  88 ). The passages  24  extend through the cap  12  to allow a fastener to couple the cap  12  with the body  14 . The cap  12  has an upper portion  26  opposite a lower portion  28 . The upper portion  26  has a peak  30  extending to a wider portion  32  while the upper portion  26  has a smaller diameter than the wider portion  32 . The lower portion  28  is configured to matingly sit within the inside diameter of the body  14 . The cap  12  is attached to the body  14  using fasteners, as explained further herein. 
         [0033]    Although a cone or dome shape is illustrated for the cap  12 , any shape is contemplated, including square, polygon, rounded, and the like. However, a cone shape is preferred since the water will flow over the jet pump tail cone insert  10  to the exit nozzle (not shown). The preferred shape is any shape that allows for the flow of water over the jet pump tail cone insert  10 , while providing the necessary change in flow area through the jet pump  46 . 
         [0034]    Several attachment means are contemplated in order to construct the jet pump tail cone insert  10  and hold the separate portions together. The cap  12  can be attached to the body  14  and the end member  16  depending upon the types of jet pumps to which it is installed. In the preferred embodiment, the separate pieces of the jet pump tail cone insert  10  can be coupled together using fasteners such as screws, bolts, latches, nails, pins, and the like. In another embodiment, the separate pieces of the jet pump tail cone insert  10  can be coupled together using an interior locking mechanism such as rivets, snaps, hooks, clamps, and the like. The attachment means utilized is designed so as to not protrude from the surface of the jet pump tail cone insert  10 , in order to have a low flow resistance of water over the jet pump tail cone insert  10 . 
         [0035]    The body  14  has an interior portion  34  opposite an exterior portion  36  and a lower portion  38  opposite an upper portion  40 . The upper portion  40  is configured to matingly receive the wider portion  32  and the lower portion  28  of the cap  12 . The body  14  has elliptical shaped forks  42  that extend from the lower portion  28 . The forks  42  have a varying thickness and taper dependent upon the draft angle of the pump housing. The thickness of the forks is dependent upon the diameter of the hub portion of the pump housing. Although a curved design is illustrated, the forks can be of any shape, as long as the forks can be received by the end member  16  and can fit within the spaces between the stator vanes  48 . The fastener (See  FIG. 5 , numerals  86  and  88 ) will be disposed through the upper portion  40  through passages  24  of the body  14 . The body  14  has openings  44  configured to receive stator vanes  48  of a jet pump  46  as illustrated in  FIGS. 2 ,  3 , and  4 . The forks  42  are configured to mount about the stator vanes  48  and be in physical contact with the stator vanes  48 . The body  14  surrounds and encompasses a portion of the stator vanes  48  of the pump  46 . The forks  42  are configured to matingly couple to the end member  16 . In another embodiment, the forks  42  are not in physical contact with the stator vanes  48 . 
         [0036]    The end member  16  has an interior portion  50  opposite an exterior portion  52  and a lower portion  54  opposite an upper portion  56 . The upper portion  56  is configured to matingly receive the forks  42  of the body  14 . The upper portion  56  has openings  58  that are configured to receive the top portion  62  of forks  42 . The end member  16  has partitions  60  that are shaped to matingly couple to the upper portion  62  and lower portions  64  of the forks  42 . The fastener (See  FIG. 5 , numerals  86  and  88 ) will extend from the top of the partition  60  through passages  24  through to the end member  16  to the bottom portion  54 . The bottom portion  54  of the end member  16  can have a diameter less than or equal to the upper portion  56 , depending upon the size of the jet pump impeller  66 . The end member  16  is matingly coupled to the impeller  66  of the jet pump  46 . The end member  16  is configured to mount about and be in physical contact with the stator vanes  48 . 
         [0037]    Both the body  14  and the end member  16  have a circular shape, although any shape is contemplated including square, polygon, rounded, and the like. However, a circular shape is preferred since the water will flow over the jet pump tail cone insert  10 . 
         [0038]    In a preferred embodiment, the jet pump tail cone insert  10  can be comprised of three separate parts that are joined together, as described above. It is contemplated that in other designs, more than three separate pieces may be required in order to fulfill the purpose of the jet pump tail cone insert  10 . The cap  12 , the body  14  and the end member  16  matingly couple to each other. The jet pump tail cone insert  10  may not be water tight. However, the jet pump tail cone insert  10  is designed to fit snuggly to the bearing hub and stator vanes in order to prevent the flow of water between the jet pump tail cone insert  10  and the stator vanes. 
         [0039]    As illustrated in  FIGS. 2 ,  3 , and  4 , the body  14  and the end member  16  are designed to accommodate any number of stator vanes  48  disposed in the jet pump  46 . The end member  16  is configured to fit inside the exterior side  70  of the impeller  66 . The end member  16  can be designed with an insertable lip  68  that fits inside the exterior side  70  of the impeller  66 . Other attachment means are contemplated and depend upon the size and type of the jet pump. The end member  16  does not interface with the impeller  66 . 
         [0040]    The body  14  and the end member  16  are configured to insert around the stator vanes  48 , thus increasing the diameter of the bearing hub  72 . The impeller  66  attaches to the bearing hub  72  via the driveshaft (or impeller shaft)  74 . Although a jet pump  46  having six stator vanes  48  is illustrated and the jet pump tail cone insert  10  is designed to accommodate this jet pump  46 , the present invention is contemplated for use in jet pumps having from about three stator vanes to about sixteen stator vanes. It is contemplated that the jet pump tail cone insert  10  can be designed by one skilled in the art to accommodate any size and type jet pump, with any number of stator vanes. 
         [0041]    The jet pump tail cone insert  10 , and accompanying parts described herein, can be comprised on any material that can tolerate the presence of water and the force of the water rushing through the jet pump. Some materials include aluminum (such as 6061 billet aluminum), stainless steel, plastic, rubber, fiberglass, composite, or a number of other available materials. As long as the finished part retains its structural integrity, there is no specific material that this design is limited to. As with the many material options there are also many manufacturing options as well, such as computer numerical control (CNC) machining, sand casting, investment casting, die casting, permanent molding, extruding, injection molding, vacuum forming, and the like. 
         [0042]    As indicated above, the dimensions of the jet pump tail cone insert  10  are specific to each jet pump model. The diameter of the insert increases if the inside diameter of the jet pump increases. A preferred overall diameter of the jet pump tail cone insert  10  can be about 70 millimeters (mm) to about 80 mm, with about 73 mm to about 75 mm preferred. 
         [0043]    In another embodiment, the efficiency of the tail cone insert  10  can be adjusted, or tuned, by lengthening or shortening the cap  12 . By lengthening or shortening, there is either an increase or decrease in pressure throughout the jet pump. As illustrated in  FIG. 5 , in one embodiment, a shim (or spacer)  76  (or several shims) can be installed between the cap  12  and the body  14 . The shim  76  would be coupled to the cap  12  by machined holes that allow the fasteners to pass through creating a sandwich effect. The cap  12  can be constructed of different lengths and shapes to achieve the desired pressure in the pump, as illustrated by the tips  80 ,  82 ,  84  in  FIG. 5 . In yet another embodiment, the cap  12  can be comprised of two separate pieces having a base  78  and a tip  80 ,  82 ,  84  in order to achieve the tuning effect. The base  78  is about one-third the total length of the cap  12 , while the tip  80 ,  82 ,  84  is about two-thirds of the length of the cap  12 . Therefore, the tip  80 ,  82 ,  84  can be interchanged with other versions (or types or styles or lengths) of the tip  80 ,  82 ,  84  without removing the base  78 . The advantage of the tip  80 ,  82 ,  84  being interchangeable is that it allows for the user to utilize different tips  80 ,  82 ,  84  to adjust the jet pump pressure. In one embodiment, the base  78  can attach to the bearing hub in order to seal the bearings. 
         [0044]      FIGS. 6 ,  7 , and  8  illustrate the jet pump tail cone insert  10  installed in a jet pump  46 .  FIG. 6  illustrates a rear view of the jet pump tail cone insert  10  installed in a jet pump  46 .  FIG. 7  is a frontal view of the impeller and jet pump tail cone insert  10  installed in a jet pump  46 .  FIG. 8  is a cross section of the jet pump tail cone insert  10  installed in a jet pump  46  taken along line B of  FIG. 7 . 
         [0045]    The jet pump tail cone insert  10  is very easily installed in a jet pump  46 . The end member  16  is positioned to physically encompass and couple to the stator vanes  48  in the jet pump  46 . The end member  16  does not physically attach to the impeller  66 . The impeller  66 , and attached end member  16  are disposed onto the drive shaft  74  such that the impeller  66  is physically coupled to the bearing hub  72  of the jet pump  46 . The body  14  is positioned to fit about the stator vanes  48 , physically encompassing the stator vanes  48 , and matingly attaches to the end member  16 . The cap  12  is then matingly coupled to the body  14 . A fastener is threaded through the three pieces (i.e., the cap  12 , the body  14 , and the end member  16 ) of the jet pump tail cone insert  10 ; securing the pieces together and holding the jet pump tail cone insert  10  onto the jet pump  46 . 
         [0046]    By installing the jet pump tail cone insert  10 , the efficiency of the jet pump  46  is increased since the center diameter of the stator vane bearing hub  72  is enlarged. The principle of this is to increase the internal pump pressure which causes the pump to stay “loaded” with water for a longer period of time than is possible using only the standard configuration of the bearing hub. In increasing the internal pressure there is an increase in the vacuum effect that the jet pump maintains with the surface of the water. Additional benefits are improved handling characteristics due to the personal water craft “gripping” the water more effectively. 
         [0047]    The present invention can be used in any jet propulsion device and is not intended to be limited to personal watercraft. The present invention increases the efficiency of an original equipment pump preventing the need for expensive tooling changes. 
         [0048]    While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention.