Patent Publication Number: US-8118242-B2

Title: Wash arm retainer for warewasher

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a commercial warewasher or dishwasher, and more specifically to an apparatus for facilitating removal of the wash arm. 
     Commercial warewashers typically employ a wash arm or nozzle-equipped manifold for spraying water at high temperature and pressure at target dishware. Such machines recycle the wash water, so that food particles are often included in the high pressure flow. Often dislodged particles collect on the wash arm and other washer components, and when exposed to the soapy water, heat and humidity of the interior of the machine, a residue forms on the wash arm and other components. Thus, the wash arm ideally is removed for cleaning on a regular basis to maintain operational efficiency of the warewasher. In heavy commercial use situations, daily cleaning is recommended. 
     U.S. Pat. No. 4,257,559 describes a conventional mechanism for removing the wash arm including a threaded closure cap which is mounted on a threaded rod which is coaxial with the wash arm. To remove the wash arm, the operator backs off the closure cap from the rod to create a clearance between the cap and the corresponding wash arm end. The clearance allows the removal of the wash arm. However, it has been found that the accumulated grime in the machine makes it difficult for the operator to move the cap after use, and grime often clogs the threads. Also, the configuration of the cap is not conducive to positive gripping by the operator. Thus, tools are often required to free the cap for efficient wash arm removal. Because of the difficulty in removing the wash arms, they may not be cleaned as frequently as recommended. 
     Another approach to removing the wash arm is disclosed in U.S. Pat. No. 5,927,616. A spring-biased rod exerts an axial clamping force on the wash or rinse arm (the terms are used interchangeably) during operation. When arm removal is desired, a “T”-shaped handle is used to retract a clamping rod against the spring force. The handle is pulled to a temporary open or retracted position where the spring is compressed, releasing clamping pressure on the wash arm and enabling removal. However, since the spring is exposed to the washing chamber of the warewasher, it is subject to becoming covered with grime, which interferes with retraction. 
     Thus there is a need for an improved apparatus for easily removing a wash arm from a warewasher, and which provides sufficient clamping force for holding the wash arm in an operational position. There is also a need for such an improved wash arm retainer which is less susceptible to accumulation of grime than conventional units. 
     BRIEF SUMMARY OF THE INVENTION 
     The above-listed needs are met or exceeded by the present wash arm retainer for a warewasher, which features a housing for a reciprocating clamping cap, the housing having a sloping cam surface. A cap rod is slidably and rotatably engaged in the housing. An actuator handle secured through the cap rod to the clamping cap follows the cam surface between an extended, clamping position and a retracted, wash arm release position. The cam is provided with two distinct slope portions, including a first, relatively gradually inclined portion for exerting clamping force against the wash arm and a second, relatively steep portion for rapid clamping cap linear displacement. In addition, the cam preferably includes a locking formation for releasably retaining the actuator handle in the clamping position. As a further enhancement, an optional spring is provided for biasing the clamping cap to the release position for more rapid wash arm replacement. To reduce operational friction, the cap is preferably rotatable relative to the cap rod. 
     More specifically, the present invention provides a wash arm retainer for a warewasher having at least one wash arm with a plurality of nozzles and being in fluid communication with an adapter for receiving a flow of fluid. The retainer includes a housing defining a through bore, having a first end and a second end, and a cam surface formed in the housing and having a clamping position and a release position. A cap rod is slidably disposed in the through bore and is provided with an actuator handle projecting from the rod and constructed and arranged for following the cam surface. 
     In another embodiment, a wash arm retainer for a warewasher having at least one wash arm with a plurality of nozzles and being in fluid communication with an adapter for receiving a flow of fluid, includes a housing defining a through bore and having a first end and a second end, a cam surface formed in a wall of the housing and beginning at the first end, the cam surface having a first, gradually inclined portion, and a second, steeply inclined portion. A cap rod is slidably disposed in the through bore and is provided with an actuator handle projecting generally transversely from the rod and constructed and arranged for following the cam surface between a clamping position and a release position. A cap is secured to an end of the cap rod in operational proximity to the first end and is configured for engaging a complementary formation on the wash arm. 
     In yet another embodiment, a wash arm retainer for a warewasher having at least one wash arm with a plurality of nozzles and being in fluid communication with an adapter for receiving a flow of fluid, includes a housing defining a through bore and having a first end and a second end, and a cam surface formed in the first end and having a clamping position and a release position. A cap rod is slidably disposed in the through bore and is provided with an actuator handle projecting generally transversely from the rod and constructed and arranged for following the cam surface. A cap is rotatably secured to an end of the cap rod in operational proximity to the first end and is configured for engaging a complementary formation on the wash arm. A return spring is disposed in the housing, and the housing further includes a shoulder in the throughbore forming a stop for the return spring. The cap rod is provided at a free end with a spring retainer for holding the spring against the shoulder and being slidably engaged in the throughbore. The spring biases the cap rod to the release position. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a top perspective view of a warewasher suitable for use with the present wash arm retainer; 
         FIG. 2  is an exploded perspective view of the present wash arm retainer; 
         FIG. 3  is a side elevation of the present wash arm retainer, with portions shown cut away for clarity; 
         FIG. 4  is a side elevation of the present wash arm retainer shown in the release position relative to a warewasher wash arm; and 
         FIG. 5  is a side elevation of the present wash arm retainer shown in the clamping position relative to a warewasher wash arm. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , a warewasher suitable for use with the present wash arm retainer is generally designated  10  and is of the type commonly referred to as a rack conveyor washer. This kind of unit is shown for illustrative purposes only, it being understood that the present wash arm retainer is useful with any kind of warewasher employing a removable wash arm, generally designated  12 . As is known in the art, the wash arm  12  is tubular for forming a fluid transporting passageway, and is provided with a plurality of linearly spaced wash nozzles  14 . Depending on the machine, such wash arms  12  may be provided with supplemental, laterally extending portions  16 , forming a wash arm manifold. The wash arm  12  is hollow and features an end  18  that has a peripheral collar flange  20  and serves as the site for releasable connection to the present wash arm retainer. 
     It is common for warewashers  10  to employ recirculated detergent-laden water and/or tank rinse water. A pump recirculates the water through the wash arms  12 , after which the water drains back into an open-topped tank. The term tank as presently used applies equally to a rinse tank in which previously used fresh rinse water is contained in a separate heated tank. In some machines, the ware is given a pumped pre-rinse prior to a final fresh water rinse. 
     The warewasher  10  encloses a wash/rinse chamber  22  through which racks of ware are intermittently moved by a conveyor mechanism  23  along tracks  24  between an upper wash arm  26  (shown hidden) and the lower wash arm  12 , each of which is conventionally supplied with a plurality of the spray nozzles  14 . A fluid, typically water is fed to the wash arms  12 ,  26  by means of a pump  28  which has a screened water intake and is passed through a conduit to the arms. The water intake is adjacent the bottom of a tank  30  which extends essentially the full length of the warewasher  10  as viewed in  FIG. 1 . At least one inspection door (not shown) is positioned in a gap  32  may expose the chamber  22  to an operator at the front of the machine if desired for any reason. 
     During normal operation, the water level will remain within one or two inches from the initial fill level, fluctuating within that range. As the pump  28  operates in a wash cycle, about four of five gallons of water are suspended in the pump  28 , conduit, the wash arms  12 ,  26  and the chamber  22  as water is recirculated and drains back from the washed ware into the tank  30 . When washing of a rack of ware is completed, the pump  28  shuts off and the water in suspension drains back into the tank  30 , causing overflow of excess water and floating soil through the standpipe. The rack of washed ware is then conveyed past a hot fresh water final rinse line (not shown) while the next rack of ware is being moved into the wash chamber. The rinse water replenishes the water in the wash chamber  22 , also causing floating soil to pass to drain. What has thus far been described is conventional in one type of warewasher and is described solely to place the invention in an environment in which it is used. 
     As described above, through operation, the wash arms  12 ,  26  become soiled with baked on food deposits, excess soap and the like, and require frequent removal for cleaning. In many applications, daily disassembly and cleaning is recommended. Conventional release mechanisms were either awkward to manipulate without tools, or became soiled themselves to the extent that their operation is impaired. 
     Referring now to  FIGS. 2 and 3 , the present wash arm retainer is generally designated  40  and addresses the drawbacks of the prior art devices. The retainer  40  includes a housing  42  configured for being mounted to a frame member or bracket  44  located in the wash/rinse chamber  22 . A through bore  46  is defined in the housing  42  which has a first end  48  and a second end  50 . A mounting arm  52  projects preferably normally from the housing and is configured for engaging the bracket  44 , such as with a threaded fastener  54 . The mounting arm  52  should be installed to the bracket  44  so that it is rotatable thereto, and the fastener  54  permits such rotation. This allows the retainer  40  to rotate out of the way for easier removal of the wash arm  12 ,  26 . It is preferred that the mounting arm  54  is provided with at least one tab  56  for maintaining a proper, preferably vertical position of the mounting arm with the bracket  44  and preventing relative rotation of these components during installation of a cleaned wash arm  12 ,  26 . 
     A main feature of the housing  42  is a cam surface  58  formed in a wall  60  of the housing at the first end  48 . The cam surface  58  includes a first portion  62  with a relatively small incline or slope, and a second portion  64  with a relatively large incline or steep slope. Also, it is preferred that the first portion  62  is provided with a locking formation  66  (best seen in  FIG. 2 ), which in the preferred embodiment is a locking notch. An optional annular shoulder  68  is defined within the through bore  46 , and provides a seat for an optional biasing element  70 , preferably a coiled return spring. 
     A cap rod  72  is slidably and rotatably engaged in the through bore  46 , and is provided with an actuator handle  74  projecting preferably normally or transversely from the cap rod, but other angular orientations are contemplated. The actuator handle  74  is constructed and arranged for following the cam surface  58 , and in so doing is linearly displaces the cap rod  72  relative to the housing  42 . In the preferred embodiment, a cap end  76  of the cap rod  72  is provided with a disk-shaped cap  78 . The cap  78  provides a clamping and plugging function for the wash arm  12 ,  26  and preferably has an annular groove  80  ( FIG. 2 ) for accommodating the complementarily shaped flange collar  20 , and a central plug or boss  81  which extends axially beyond a periphery of the cap  78  ( FIG. 3 ). Also, the cap  78  is secured to the cap end  76 , and is preferably rotatable relative to the cap end to facilitate the removal of the wash arm  12  as will be described below. In the preferred embodiment, this rotatability is obtained by the cap end  76  matingly engaging an axial opening  82  and being flared by a cone tool or peened over as is known in the art. Alternative structure is contemplated for achieving this rotatability, including, but not limited to the use of cotter pins or various styles of retaining rings. 
     In an alternate embodiment, the collar  20  has the cap  78  fixed thereto or is otherwise plugged, and the cap end  76  directly exerts a clamping force on the plugged end  18  of the wash arm  12 . The movement of the cap rod  72  relative to the housing  42  between a retracted and a clamping position is the same whether or not the cap  78  is secured to the cap end  76 . 
     Opposite the cap end  76 , a spring end  84  of the cap rod  72  is axially bored and threaded to create a socket  86  for receiving a retainer, preferably a flanged fastener  88 . The fastener  88  may be unitary or may be a fastener with a separate disk washer as is known in the art. An outer diameter of a flange  90  of the fastener  88  is tightly yet slidably dimensioned for engagement in the through bore  46 . When provided, the coiled return spring  70  is axially engaged about the spring end  84  and held in place by the flanged fastener  88 . Opposite the fastener  88 , the spring  70  rests upon the shoulder  68 . 
     Referring now to  FIGS. 3-5 , it will be seen that the actuator handle  74  follows the cam surface  58  between a clamping or extended position ( FIG. 5 ) in which the handle is disposed at the locking formation  66 , which forms a cap end of the first cam portion  62 , and a release or retracted position ( FIGS. 3 and 4 ) in which the handle is disposed at an opposite end  92  of the second cam portion  64 . In traveling between the two positions, the actuator handle  74  is rotatably displaced 180°. Also, it will be seen that once the actuator handle  74  has engaged the full length of the second cam portion  64 , there is a significant linear displacement of the cap  78 , compared to the travel of the handle upon the first cam portion  62 . Further, the second cam portion  64  defines the majority of the linear displacement of the cap rod  72  relative to the housing  42 . 
     As seen in  FIG. 4 , when removal of the wash arm  12 ,  26  is required, the actuator handle  74  is moved to the release position. Once the cap rod  72  is in the retracted or release position, there is sufficient clearance between the cap  78  and the collar  20  for rotation of the wash arm retainer  40  about the fastener  54  and away from the wash arm to permit easy removal of the wash arm  12 ,  26 . Also, when the return spring  70  is provided, it biases the cap rod  72  to the release position. Without the spring  70 , the user merely physically moves the handle  74  to the release position. In addition, when in the clamped position ( FIG. 5 ), the spring  70  holds the cap rod  72  in the locking formation  66 . Further, the disposition of the spring  70  within the housing  42  and protected by the flanged fastener  88  protects the spring from operational grime, which was a problem in prior art. 
     Once the wash arm  12  has been cleaned and positioned, an opposite end  94  of the wash arm  12 ,  26  is matingly engaged in an adapter  96  from which the wash or rinse water emanates. The wash arm retainer  40  is then rotated to the vertical position shown in  FIG. 5 . The tab  56  engages the bracket  44  and prevents the housing  42  from rotating beyond a vertical position when actuating the handle  74  to engage the clamping action. Next, the actuator handle  74  is moved along the second portion  64  of the cam surface  58 , which provides significant linear displacement. Upon reaching the first cam portion  62 , the actuator handle  74  has traveled most of the way to the clamping position. The relatively gradual slope of the first cam portion  62  allows the user to provide a finer adjustment and a gradual application of clamping force as the wash arm  12  is moved into position. Simultaneously with the movement of the actuator handle  74 , the user manipulates the wash arm  12 ,  26  so that the protruding plug  81  performs a locating function for guiding the collar  20  into the groove  80  on the cap  78 . At least one border defining the groove  80  on the cap  78  is chamfered to facilitate this locating function. 
     Upon the wash arm reaching the operational position, the actuator handle  74  is received in the locking formation  66 . At this point, as the handle  74  is moved toward the locking formation  66 , the rotatablity of the cap  78  relative to the cap rod  72  reduces frictional load on the handle. While other materials are contemplated, it will be understood that the housing  42 , the cap rod  72 , the actuator handle  74  and the cap  78  are preferably made of stainless steel. The components are preferably produced by casting, however other fabrication techniques are contemplated. 
     While a particular embodiment of the present wash arm retainer for a warewasher has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.