Abstract:
A jet for use in a whirlpool tub or spa according to a first aspect of the invention includes a motor assembly including an electric motor disposed inside a motor housing, which motor housing includes a frontwardly facing, water-tight recess. Suitable means are provided for mounting the motor assembly in a hole in a tub wall. A centrifugal pump assembly used in the jet includes a rotor-impeller having a rear, magnetically attractable rotor disposable in the recess of the motor assembly and a front set of blades. A cover having water inlet and outlet openings is removably securable over the rotor-impeller. A sensor system is provided which can be connected to the motor to shut off the motor when the cover is removed from the centrifugal pump assembly. The sensor system includes a sensor target disposed on a rear surface of the cover, and a sensor disposed on or near the pump assembly, such that the sensor detects the sensor target only when the cover is secured over the centrifugal pump assembly in one or more predetermined positions.

Description:
[0001]    The invention relates to whirlpool bathtub jet apparatus of the type wherein one or more jet assemblies are installed in a tub wall. 
       BACKGROUND OF THE INVENTION 
       [0002]    Whirlpool jets of the type used in spas and bathtubs are used to recirculate water inside the tub or spa, with or without injection of air. For this purpose, the jet assembly is set in a hole in the tub wall and powered by an electric motor that drives an impeller. Recently, “pipeless” jets have become popular wherein the jet draws water into a chamber inside the unit, redirects its flow in a radial or lateral direction, and then ejects it from one or more nozzles, without the use of a pipe that carries water from an inlet to an outlet location on the tub wall. See Jaworski U.S. Pat. No. 4,853,987 and Booth U.S. Pat. Nos. 5,414,878 and 5,587,023. A plastic cover or escutcheon plate covers the mouth of the jet, and in many designs provides openings for the intake opening(s) and outlet nozzle. 
         [0003]    The inlet and outlet positions will depend on the type of centrifugal pump being used. In a mixed flow pump, the nozzle is located at or near the center with the intake openings around the outside of the cover plate. In a radial flow pump, the intake is at the center with nozzles on the outside, depending on the arrangement of the impeller and the casing enclosing it. 
         [0004]    Most pipeless jets are driven by an electric motor positioned behind the water circulation chamber. The impeller can be driven by a drive shaft that extends through a water tight hole in the back wall of the chamber, as shown in the Booth patents cited above. To avoid the need for a drive shaft that penetrates the plastic pump housing, more recent jet designs provide the impeller with a magnetic rotor that is positioned so that the impeller can be driven directly by the magnetic field created by the electric motor&#39;s stator, which field extends through the rear wall of the water chamber. 
         [0005]    Known spa jets have also used Hall effect sensors or switches for purposes of allowing a user to control the jet, or to monitor the state of the impeller. See, for example, U.S. Pat. Nos. 5,983,416 and 6,295,662. In a prior art jet assembly sold by Sanijet Corporation known as the 30008, the pump housing was of the mixed-flow type. It included an escutcheon outer pump housing section attached to the inside of the escutcheon, an impeller and an inner pump housing section which fit together with the outer pump housing section. This pump assembly was removed as a unit for cleaning. It proved cumbersome in this device to provide an interlock that would turn the pump motor off when the pump housing had been removed. A magnet was housed in a molded plastic projection on the outer pump housing section, the inner section had a tubular holder on its outside for housing a metal flux pin. When the pump housing sections were secured together, the magnet and flux pin are aligned with each other. When pump assembly was then inserted into the pump casing, the magnet and flux pin aligned with a hall effect sensor positioned behind inner housing section. 
         [0006]    The sensor sent a signal indicating when all components were correctly installed, otherwise the pump motor would not run. However, it was not of great utility from a safety standpoint. In such a mixed flow pump where the impeller is enclosed in a housing and is removed at the same time as the cover, there is no danger that the impeller will run when the device has been disassembled. Sensor responsiveness was an issue because the magnet was spaced from the sensor and a flux pin had to be interposed between them. The present invention addresses these and other limitations. 
         [0007]    Pipeless jet assemblies can be potentially hazardous in certain situations. If a bather&#39;s hair becomes caught in the jet while it is running, the bather could drown. Many jet designs permit the cover to be removed manually for purposes of cleaning. However, injury could result if the cover is removed while the impeller is running. A pipeless jet marketed by Lexor Inc. has a plastic housing that covers the blades from the front of the impeller, so that the blades are only exposed around the side where water is ejected circumferentially. These covered blades also are more difficult to clean. The present invention addresses these drawbacks. 
       SUMMARY OF THE INVENTION 
       [0008]    A jet for use in a whirlpool tub or spa according to a first aspect of the invention includes a motor assembly including an electric motor disposed inside a motor housing, which motor housing includes a frontwardly facing, water-tight recess. Suitable means are provided for mounting the motor assembly in a hole in a tub wall, including the 3-piece mounting system set forth in the detail description hereafter, as well as others known in the art, such as using J-latch assemblies as shown in the foregoing Booth patents, or use of external threads on the pump housing and a threaded plastic ring mounted thereon, which is tightened to clamp the jet to the tub wall. A centrifugal pump assembly used in the jet includes a rotor-impeller having a rear, magnetically attractable rotor disposable in the recess of the motor assembly and a front set of blades. A cover having water inlet and outlet openings is removably securable over the rotor-impeller. A sensor system is provided which can be connected to the motor to shut off the motor when the cover is removed from the centrifugal pump assembly. The sensor system includes a sensor target disposed on a rear surface of the cover, and a sensor disposed on or near the pump assembly, such that the sensor detects the sensor target only when the cover is secured over the centrifugal pump assembly in one or more predetermined positions. Known centrifugal pumps used in spa jets lack such a sensor system but have a much more acute need for it than mixed flow pumps wherein the blades are removed at the same time as cover, making it impossible for the user to be injured by the uncovered blades. 
         [0009]    According to a further aspect of the invention, two or more sensor targets are provided such that the sensor detects one of the sensor targets only when the cover is secured over the centrifugal pump assembly in two or more predetermined positions. The cover has a plurality of small water inlet openings distributed about its surface, and one or more off-center outlet openings. By repositioning the cover, the user can vary the water flow direction from the outlet opening depending on which predetermined position the cover is secured in. If more than one outlet opening or nozzle is provided in the cover, then this embodiment of the invention requires that these not be placed so symmetrically that changing from one predetermined position to another causes the outlet openings to exchange positions and thereby does not result in any change in water flow in the tub. 
         [0010]    The invention further provides an improved system for mounting a motor assembly in a tub wall that uses detents instead of threads. These and other aspects of the invention are further discussed in the detailed description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    In the accompanying drawings, wherein like numerals denote like elements: 
           [0012]      FIG. 1  is a side view of a jet according to the invention installed in a tub wall, with the tub wall in section; 
           [0013]      FIG. 2  is a front exploded view of the jet of  FIG. 1 , with the tub wall partly broken away; 
           [0014]      FIG. 3  is a rear exploded view of the motor assembly shown in  FIG. 2 ; 
           [0015]      FIG. 4  is an enlarged view of the clamp ring and flange bushing shown in  FIG. 2 ; 
           [0016]      FIG. 5A  is a partial sectional view of the bushing and clamp ring shown in  FIG. 4  in an unlocked position, after insertion of the clamp ring into the bushing; 
           [0017]      FIG. 5B  is the same view as  FIG. 5A , with the components in a locked position; 
           [0018]      FIG. 6  is a front view of the jet shown in  FIG. 1 ; 
           [0019]      FIG. 7  is a sectional view taken along the line  7 - 7  in  FIG. 6 ; 
           [0020]      FIG. 8  is an exploded rear view of the cover, flow guide and rotor-impeller of  FIG. 2 ; 
           [0021]      FIG. 9  is a back view of the cover and flow guide of  FIG. 8 , assembled; 
           [0022]      FIG. 10  is a sectional view taken along the line  10 - 10  in  FIG. 9 ; and 
           [0023]      FIGS. 11A and 11B  are front views of two jet arrangements according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Referring to  FIGS. 1 to 3 , a whirlpool jet  10  according to the invention is configured for mounting in a hole  11  in the side of a tub wall  12 . The jet  10  includes a motor assembly  15  wherein a plastic annular pump case  14  has an electric motor  16  coupled to its rear end. A DC motor is used in this example but an AC motor could be used. Motor  16  has a plastic tubular housing  17  which is sealed and capped at both ends. A front stainless steel end cap of housing  17  has a concave interior recess  18  in which water from the tub will circulate. Housing  17  is secured to case  14  by means of a clamp ring  19  having four radial flanges  21  having holes  51  through which retainer screws  22  extend. Clamp ring  19  slides over the rear end of housing  17  and has a front edge  23  that engages an outwardly directed rim  24  at the front of housing  17 . Once so engaged, screws  22  are set in rearwardly opening threaded holes in cylindrical projections  25  on the back of pump case  14 , whereby motor  16  is clamped between case  14  and ring  19 . To render the assembly water-tight, a first, smaller diameter elastomeric O-ring  26  is positioned in a rearwardly facing annular groove  29  in pump case  14 . A second, larger diameter O-ring  27  fits in an annular groove  30  on a front rim  28  of case  14 . 
         [0025]    An interlock sensor  31 , preferably a Hall effect switch or sensor, is set in a rearwardly opening socket  32  in case  14  so that its front end is close to the flat front surface of rim  28 . A wire  33  ending in a connector  34  extends rearwardly for direction connection to motor  16 , or a separate controller  35  for motor  16 . Sensor  31  is used to cut power to motor  16  unless the presence of a magnet is detected in front of it as described further below. 
         [0026]    Motor assembly  15  comprising case  14 , motor  16  and clamp ring  19  is secured in hole  11  by means of a mounting system including a tubular flange bushing  41 , gasket  42  and a lock ring  43 . Gasket  42  is set behind a front radial rim  44  of bushing  41 . Rim  44  has a greater diameter than hole  11 , whereby gasket  42  is clamped against the inside of the tub wall  12  when an externally threaded, rear end portion  46  of bushing  41  is inserted fully into hole  11 . Lock ring  43  is internally threaded and is threadedly coupled to end portion  46  on the outside of the tub, securing bushing  41 , gasket  42  and lock ring  43  to hole  11 . The assembly of case  14 , motor  16  and ring  19  fit into the front end of bushing  41  into engagement with an inwardly directed lip  45  in front of shoulders  47  of bushing  41 . 
         [0027]    Referring to  FIGS. 4 ,  5 A and  5 B, the invention provides an innovative system for mounting, removing and replacing the motor assembly  15  from the inside of the tub without need for access to the outside of the tub to secure the motor assembly in position. Four shoulders  47  are positioned 90° apart are shown, each of which has a circumferentially directed, integrally molded plastic tab  48  with a curved notch  49  in its distal end. The gaps between shoulders  47  provide pass-through clearance for tabs  21  of clamp ring  19 . Screws  22  extend through four holes  51  at the centers of tabs  21 . Upon initial insertion of the motor assembly into bushing  41 , tabs  21  are behind and spaced from tabs  48  as shown in  FIG. 5A . The installer then twists the motor assembly relative to bushing  41  secured to the tub wall  12  so that cylindrical projections  25  move towards tabs  48 . Curved notches  49  are profiled such that the ends of tabs  48  must resiliently deform in order to snap-fit each projection  25  into its notch  49 , assuming the position shown in  FIG. 5B . When motor assembly  15  is rotated into the detent lock position, leading edges of tabs  21  pass behind tabs  48  to secure motor assembly  15  from axial pullout. This connection is engineered so that considerable force is needed to disengage projections  25  from notches  49 , e.g. use of a spanner tool is required, making it unlikely that a user could accidentally disengage the unit during normal use. 
         [0028]    A pump assembly  60  for use with the motor assembly  15  includes a centrifugal rotor-impeller  61 , an outer escutcheon or cover  62 , and a flow guide insert  63 . Rotor-impeller  61  includes a hemispherical steel bowl or shell  64  which houses the rotor magnet  50 . Shell  64  fits into concave interior recess  18 . As shown in  FIG. 7 , a plastic internal frame  66  supports shell  64 . Shell  64  has a rearwardly opening socket  67  that fits over a spindle  68  formed on concave recess  18  of motor housing  17 . Spindle  68  is a hollow projection that terminates and secures a ceramic ball bearing  69  that is received in socket  67 . Frame  66  supports rotor-impeller  61  for rotation on bearing  69  of spindle  68 . To provide rotation clearance but with a minimum gap between rotor magnet  50  and the stator inside of motor housing  17  behind recess  18  and to avoid excess friction, the curvature of shell  64  is spaced from the curved wall of recess  18 . Integral with frame  66  are a series of blades  71  configured so that upon rotation of the rotor-impeller  61 , water is drawn in at the center of rotor-impeller  61  and then ejected out the sides. Rotation of rotor-impeller  61  is induced magnetically by motor  16  acting through the front of motor housing  17 . This type of system for powering a centrifugal rotor-impeller is known in the art. 
         [0029]    Cover  62  with flow guide  63  attached as described hereafter is secured over rotor-impeller  61 . Flow guide (pump cap)  63  is removably attached to pump case  14 . Flow guide  63  has a pair of curved lips  65  on opposite sides that fit though corresponding slots  70  on the inside of rim  28  of pump case  14 . Once lips  65  are fully inserted into case  14 , flow guide  63  is rotated 90 degrees into a locked position in which lips  65  are behind the inner edge of rim  28 , the position shown in  FIG. 2 . This serves to hold pump cap  63  and pump case  14  together under pressure. Flow guide  63  contains channels to properly direct suction and discharge flow to and from impeller  61  as described further hereafter, and in combination with pump case  14  and rim  24  of motor housing  17  provides the pressure boundary of the pump due to impeller rotation. 
         [0030]    Cover  62  is a one piece plastic disk having an annular rim  73  that fits over the outside of bushing  41 . It is rotationally positioned and mounted onto bushing  41  my means of a pair of detent projections  74  located 180° apart on the front face of rim  44  of bushing  41 . Rounded, inwardly directed projections  76  on rim  73  releasably engage outwardly facing rounded grooves  77  in projections  74 , enabling cover  62  to be hand tightened and removed. The placement of projections  74 ,  76  permits the cap to be mounted in either of two positions 180° apart, allowing the nozzle clearance opening  78  (provides clearance for  96 ), which is located off center, to be positioned above center (as shown), below center, or right/left, if bushing  41  is repositioned so that projections  74  are positioned left and right, or additional projections  74  are provided. As a result, in a whirlpool tub or spa according to the invention, jets can be placed in pairs on a tub wall  12  with nozzles in closer or further apart positions, as shown in  FIGS. 11A and 11B . Use of detents in this manner also has advantages over a threaded on cap, in that bacteria tend to collect in the plastic threads. 
         [0031]    Cover  62  further has intake holes  79  distributed around its surface. Holes  79  are preferably small and spaced apart over an outer annular portion of cover  62  to avoid user hair entrapment than can result when strong suction is created over a small area of the jet. There is also a small outer radial suction gap  90  ( FIG. 7 ) between cover  62  and bushing  41 . A pair of plastic posts  81  are formed on the inside of cover  62  near the outer rim  73 . Posts  81  have rearwardly opening, optionally countersunk blind holes therein in which a pair of magnets  82  are inserted. When the jet is fully assembled as shown in  FIG. 7 , one of magnets  82  is in close proximity to the front of Hall effect sensor  31 , spaced therefrom only by the thickness of front rim  28  of case  14 , which may for example be from 0.1 to 0.2 inch. This provides for a more reliable sensor function that a design wherein the magnet and sensor are spaced apart by 0.6 inch or more, with a flux pin in between. 
         [0032]    One post  81 A corresponds to the nozzle position shown in the drawings, whereas the opposing post  81 B aligns with sensor  31  when the nozzle opening  78  is placed in its alternative position as discussed above. By providing multiple magnets in this manner, the jet assembly can be made operable in two or more predetermined positions of cover  62  (and guide  63 ) relative to the rest of the jet assembly. For additional safety, it is preferred that sensor  31  be a unipolar Hall effect sensor, such that placing the cap on backwards will not allow the motor  16  to run, even if a magnet  82  is close to sensor  31 . 
         [0033]    Cover  62  snaps onto pump cap  63  which provides jar lid type handle for inserting pump cap and rotational lock of pump cap into pump case. It also prevents a user from touching the spinning blades  71  at pump caps suction opening  94 . One of it&#39;s most important functions is to provide a large outer annular surface area for multiple small suction openings whose total area is greater than suction opening  94  below. 
         [0034]    Flow guide  63  is a plastic insert in the shape of a two sided cup having a cylindrical outer wall  86  from the front of which a pair of opposed, undercut tabs  87  project. Tabs  87  resiliently engage complementary shaped grooves  88  in a pair of projections  89  formed in the inside of cover  62 , inwardly from the intake holes  79 . The user can squeeze tabs  87  in order to remove guide  63  for cleaning after cover  62  has been removed. Posts  81  have rails  80  thereon which slide into corresponding grooves  85  in flow guide  63  so that tabs  87  are in alignment with projections  89 . 
         [0035]    A bottom wall  91  of guide  63  is located in between the front and rear edges of outer wall  86 , dividing guide  63  into a front flow chamber  92  and a back flow chamber  93 . Chambers  92 ,  93  are in communication by means of a central hole  94  at the center of bottom wall  91 , which hole is positioned directly over the center of rotor-impeller  61 . Water flowing in the direction of the arrows in  FIG. 7  passes through chamber  92  and hole  94  and is propelled outwardly by rotary movement blades  71  into the outer part of chamber  93 . Guide  63  has a tube (discharge nozzle)  96  formed therein which fits closely inside of opening  78  and which communicates with chamber  93 . The pump pressure forces the water in chamber  93  to jet out through tube  96  and into the tub. Tube  96  is open on one side in chamber  93 , and the back of wall  91  is configured as a curved channel  95  to efficiently channel water through the nozzle. 
         [0036]    Flow guide  63  is configured to guide water entering through holes  79  in cover  62  to the center of the device while minimizing pressure drop, and then allow it to flow out through the nozzle (tube  96 ) without any internal countercurrent flow between water entering the jet and water exiting the jet. When cover  62  and guide  63  are removed together, rotor-impeller  61  may then be manually removed for cleaning. Unlike a known design wherein the frame of the rotor-impeller includes a front enclosure that conceals the blades, the rotor-impeller  61  with exposed blades  71  can be cleaned more easily and thoroughly. However, since blades  71  are difficult to grasp, roller-impeller preferably has a central knob  100  that can be grasped by the user once cover  62  is removed. Since the blades  71  are exposed, it is especially important that motor  16  be cut off by sensor  31  when cover  62  is not in place. 
         [0037]    It will also be noted from the foregoing that the user removes cover  62  by twisting it, which twisting can be in the same direction as the twisting action that would disengage the motor assembly  15  from flange bushing  41 . To prevent this from happening, the force required to disengage the motor assembly  15  from its detents is considerably greater than the force needed to unlock cover  62 , and may require use of a tool such as a spanner set in a pair of opposed notches  105  on the inside of rim  28  of case  14 . The whirlpool jet as described herein can thus be partially taken apart for cleaning, or removed and replaced in its entirely if for example the motor fails, without need to access components on the outside of the tub wall, which is often covered by a tub skirt, wall, or the like. 
         [0038]    Lock ring  43  in the preceding embodiment may be an ordinary threaded plastic ring comprising a front flange  101  with a flat surface for engaging the outside of the tub wall, and an internally threaded body  102  which tightens onto threaded end portion  46 . As shown, ring  43  is further improved by providing a set of radially spaced arms  103  formed by radial cuts  104  part way through the width of flange  101 . The insides of arms  103  have rounded projections  106  thereon which engage the outside of the tub wall  12  as shown in  FIG. 1 . The outside of a tub wall is often uneven, and arms  103  can flex to varying degrees as ring  43  is tightened, providing better locking engagement. 
         [0039]    The foregoing embodiment is the presently preferred embodiment of the claimed invention. It will be readily apparent to one skilled in the art that many variations of the invention can be made without deviating from the scope of the claims. For example, the Hall effect sensor may be replaced by one or more light sensors, and the magnets by reflectors, with transparent plastic used where needed to allow light transmission. This and other modifications are considered within the scope of the appended claims.