Patent Publication Number: US-10307036-B2

Title: Warewash machine with removable rotating arm and related method

Description:
CROSS-REFERENCES 
     This application is a divisional of U.S. application Ser. No. 13/738,877, filed Jan. 10, 2013, which in turn claims the benefit of U.S. Provisional Application Ser. No. 61/598,695, filed Feb. 14, 2012, both incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates generally to machines used to wash kitchen wares such as dishes, glasses, utensils, pots, and pans; and more particularly to a rotatable warewash arm construction for such machines. 
     BACKGROUND 
     Box-type warewash machines (aka batch-type machines) utilize rotating warewash arms to deliver liquid onto wares in a wash chamber during the wash process. The warewash arms typically are mounted onto a fluid supply shaft. In the past, the warewash arms were permanently mounted on the supply shaft such that replacement of the warewash arm requires removing the supply shaft from the warewash machine with tools. Such rotating arms could also be used in various zones within the elongated chambers of conveyor-type machines, though more commonly conveyor-type machines utilize fixed arms. 
     Accordingly, it would be desirable to provide a mechanism that allows a rotating warewash arm to be easily attached and removed by the user without tools. It would also be desirable to provide a liquid supply shaft, attachable to the rotating warewash arm, that allows for less wear than the present state of the art. 
     SUMMARY 
     In one aspect, a warewash machine arm mechanism includes a liquid supply shaft assembly including a rotatable sleeve bearing mounted thereon, and an arm assembly including an elongated interior liquid flow space along an arm body and one or more liquid ejection orifices. The arm assembly is releasably mounted to the supply shaft assembly via a latch mechanism of the arm assembly that engages the rotatable sleeve bearing such that the arm assembly rotates with the rotatable sleeve bearing during ejection of liquid from the liquid ejection orifices. 
     In one implementation of the arm mechanism of the preceding paragraph, the liquid supply shaft assembly extends downward, the arm assembly is a rinse arm assembly, and a wash arm assembly is also mounted on the liquid supply shaft assembly, the wash arm assembly supported on the supply shaft assembly by the rinse arm assembly. 
     In the implementation of the preceding paragraph, the arm assembly may include a bushing having a lower portion extending downward from an arm body of the wash arm assembly, the bushing including a downwardly facing bearing surface that sits atop an upper portion of the rinse arm assembly to facilitate relative rotation between the rinse arm assembly and the wash arm assembly. 
     In the arm mechanism of any of the three preceding paragraphs, the rotatable sleeve bearing may be fixed against axial removal from the supply shaft assembly. 
     In the arm mechanism of any of the four preceding paragraphs, the rotatable sleeve bearing may include a recessed exterior surface portion that is engaged by the latch mechanism. 
     In the arm mechanism of any of the five preceding paragraphs, the arm assembly may include a mount hub with a mount opening disposed about the liquid supply shaft assembly, and the latch mechanism includes at least first and second actuators, each actuator having an interior end portion biased toward an axis of the mount opening and an exterior end portion biased away from the axis, such that movement of the exterior end portion of the actuator toward the axis moves the interior end portion away from the axis. 
     In the arm mechanism of the preceding paragraph, a lower end portion of the supply shaft assembly may include a chamfer such that as the mount hub is moved axially onto the supply shaft assembly during assembly, the chamfer engages the interior end portion of each actuator forcing the end portion outward to permit the mount hub to slide onto the supply shaft assembly. 
     In the arm mechanism of any of the seven preceding paragraphs, where the arm assembly is a rinse arm assembly, a tubular wall of the supply shaft assembly may include at least one port therethrough for delivering rinse liquid to an interface between an external surface of the tubular wall and an internal surface of the rotatable sleeve bearing in order to lubricate the interface with the rinse liquid. 
     In the arm mechanism of any of the eight preceding paragraphs, the external surface of the tubular wall may include a peripherally extending groove and an external side of the port is located in the groove to facilitate movement of rinse liquid circumferentially about the interface. 
     A warewash machine including the arm mechanism of any of the nine preceding paragraphs may be formed with a chamber for receiving wares to be washed and a fluid path that is connected for delivering rinse liquid to the supply shaft assembly. 
     In another aspect, a warewash machine arm for ejecting liquid in a warewash machine includes an arm body formed to provide an elongated liquid space along an arm axis, the arm body including one or more liquid ejection orifices. A mount hub is connected to the arm body and includes a mount opening and at least first and second actuators. Each actuator has an interior end portion biased toward an axis of the mount opening and exterior end portion biased away from the axis, such that movement of the exterior end portion of the actuator toward the axis moves the interior end portion away from the axis. 
     In the arm of the preceding paragraph, at least one compression spring may be compressed between portions of the first and second actuators to provide the biased arrangement. 
     In the arm of either of the two preceding paragraphs, the exterior end portions of the actuators may be diametrically opposed to each other. 
     In a warewash machine including the arm of any of the three preceding paragraphs, the machine may further include a supply shaft assembly including a rotatable sleeve bearing, the arm mounted to the rotatable sleeve bearing via the actuators engaging the rotatable sleeve bearing. 
     In the warewash machine of the preceding paragraph, the rotatable sleeve bearing may be mounted about a hollow axle shaft having an end portion configured to prevent axial removal of the rotatable sleeve bearing. 
     In the warewash machine of either of the two preceding paragraphs, the supply shaft assembly may extend downward from an upper portion of the warewash machine, the arm is a rinse arm, and a wash arm assembly is also mounted on the supply shaft assembly, the wash arm assembly supported on the supply shaft assembly by the rinse arm. 
     In the warewash machine of the preceding paragraph, the wash arm assembly may include a bushing having a lower portion extending downward from an arm body of the wash arm assembly, the bushing including a downwardly facing bearing surface that sits atop an upper portion of the arm mount hub. 
     In a further aspect, a method of spraying liquid onto wares within a chamber of a warewash machine includes the steps of: utilizing an elongated arm body with multiple spray nozzles thereon and a releasable latch mechanism connected thereto; utilizing a supply shaft assembly having a rotatable sleeve bearing thereon that is supported against axial removal from the supply shaft assembly; mounting the elongated arm body onto the supply shaft assembly by engaging the releasable latch mechanism with the rotatable sleeve bearing; flowing liquid through the supply shaft assembly and into the arm body such that the liquid is sprayed from the nozzles as the arm body rotates; where the releasable latch mechanism engages the rotatable sleeve bearing to cause the rotatable sleeve bearing to rotate with the arm body. 
     In the foregoing method, the releasable latch mechanism may have a biased position, the mounting step involves moving the releasable latch mechanism over an end of the supply shaft assembly and into alignment with the rotatable sleeve bearing, and during such movement an end portion of the supply shaft assembly slidingly interacts with a portion of the releasable latch mechanism to move the releasable latch mechanism out of its biased position to permit mounting. 
     In the method of either of the two preceding paragraphs, a wall of the supply shaft assembly may include at least one port therethrough for delivering liquid to an interface between an external surface of the tubular wall and an internal surface of the rotatable sleeve bearing in order to lubricate the interface with the liquid as the rotatable sleeve bearing rotates. 
     In the method of any of the three preceding paragraphs, the external surface of the wall may include a peripherally extending groove and an external side of the port is located in the groove to facilitate movement of rinse liquid circumferentially about the interface. 
     In yet another aspect, a warewash machine arm for ejecting liquid in a warewash machine includes an arm body defining an elongated liquid and at least one orifice disposed along the arm body. To the arm is removably attached a warewash arm mount hub. Two resiliently biased actuators are symmetrically disposed about the hub. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic depiction of a batch-type warewasher; 
         FIG. 2  is an exploded view of one embodiment of a warewash machine arm mount and a warewash machine liquid supply assembly; 
         FIG. 3  is an exploded view of one embodiment of a warewash machine arm, warewash machine arm mount, gasket and a warewash machine liquid supply assembly; 
         FIG. 4  is a top view of one embodiment of a warewash machine arm, warewash machine arm mount, and a warewash machine liquid supply assembly; 
         FIG. 5  is an exploded view of one embodiment of a warewash machine arm, warewash machine arm mount, gasket and a warewash machine liquid supply assembly wherein a cover of the mount housing is removed; 
         FIG. 6  is an exploded view of one embodiment of a warewash machine arm actuator mechanism; 
         FIG. 7  is a top view of a warewash machine liquid supply assembly; 
         FIG. 8  is an exploded view of a warewash machine liquid supply assembly; 
         FIG. 9  is a cross section of the warewash machine arm, warewash machine arm mount, and a warewash machine liquid supply assembly of  FIG. 4 , viewed on a cross sectional plane perpendicular to the arm axis; 
         FIG. 10  is a cross section of the warewash machine arm, warewash machine arm mount, and a warewash machine liquid supply assembly of  FIG. 4 , viewed on a cross sectional plane along the arm axis; 
         FIG. 11  is a top view of an embodiment of the actuator mechanism of  FIG. 6 , without the cover, in a closed position and ready for use in a warewash machine; 
         FIG. 12  is a top view of an embodiment of the actuator mechanism of  FIG. 6 , without the cover, in an open position for removal or attachment of the warewash mount to a warewash machine liquid supply assembly; 
         FIG. 13  is a partially exploded view of a hanging rinse arm and wash arm combination; and 
         FIG. 14  is a cross-section of the assembled rinse arm and wash arm combination of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a schematic depiction of an exemplary batch-type warewasher  200  is shown, and includes a chamber  202  in which wares are placed for cleaning via opening of a pivoting access door  204 . At the bottom of the chamber  202 , a rotatable wash arm  206  is provided and includes multiple nozzles  208  that eject wash liquid during a cleaning operation. The wash liquid contacts the wares for cleaning and then falls back down into a collection sump  210  that may include a heater element  212 . At least some of the wash liquid is ejected in a manner that causes the arm to rotate. A recirculation path is provided via piping  214 , pump  216  and piping  218  to move the wash liquid back to the wash arm  206 . A rotatable rinse arm  220  with nozzles  222  is also shown, to which fresh rinsing liquid may be fed via a rinse line made up of fresh water input line  224 , valve  226 , boiler  228  and line  230 . A controller  232  is also shown, which may typically be programmed to carry out one or more selectable ware cleaning cycles that generally each include at least a washing step (e.g., that may run for 30-150 seconds, followed by a rinsing step (e.g., that may run for 7-30 seconds), though many other variations are possible. Although the illustrated machine  10  includes only lower arms, such machines may also include upper rinse and wash arms shown schematically as  234  and  236 . Such machines may also include other features, such as blowers for a drying step at the end of a ware cleaning cycle. Machines with hood type doors, as opposed to the illustrated pivoting door, are also known. 
     The warewash arm construction described in detail below can be used in such a batch-type machine, or any other type of warewash machine in which a rotating spray arm is desired. 
     Referring to  FIGS. 5, 6, 9, and 10 , one embodiment of a warewash machine arm for ejecting liquid in a warewash machine is disclosed. The arm includes an arm body  10  formed to provide an elongated internal liquid space  11  along an arm axis. The liquid space  11  is in communication with one or more nozzle orifices  12  for ejecting liquid from the arm and a mount opening  13 . A warewash arm mount includes a base  14 , cover  30  and internal actuator. The base  14  is mounted on arm body  10  and includes a top base surface  15 , a bottom base surface  16 , a base edge  17 , and a base port  18  passing from top base surface  15  to bottom base surface  16  wherein base port  18  is aligned with mount opening  13 . A first actuator  19  and second actuator  20  are movably mounted on top base surface  15 . Actuator  19  includes a top surface  21 , a bottom surface  22 , an outer edge  23  and a port  24  passing from top surface  21  to bottom surface  22 . Another actuator  20  includes a top surface  25 , a bottom surface  26 , an outer edge  27  and a port  28  passing from top surface  25  to bottom surface  26 . Actuator port  24  and actuator port  28  are aligned with mount opening  13  and base port  18 . Actuators  19 ,  20  are symmetrically disposed with respect to base port  13 , and resiliently biased one against each other. Cover  30  is in overlying contact with actuators  19  and  20 . The cover includes a top surface  31 , a bottom surface  32  and a port  34  passing from top surface  31  to bottom surface  32 . Cover  30  is mounted to base  14  and cover port  34  is aligned with mount opening  13 , base port  18 , actuator port  24 , and actuator port  28 . 
     In the illustrated embodiment, base  14  and cover  30  are shaped to define at least one degree of symmetry. For example base  14  and/or cover  30  are symmetric about a rotational axis passing through base port  18  and cover port  34 , respectively. In another embodiment, base and/or cover are symmetric about at least one plane of symmetry. Components disposed in such symmetry relationships allow the device to be balanced and/or rotate smoothly and/or with minimized wear in use. 
     Actuators  19  and  20  are mounted on base  14  in an opposed relationship about a rotational axis (e.g., 180 degrees apart). In other embodiments, there may be more than 2 actuators in rotationally symmetric relationship (e.g., 3 actuators 120 degrees apart). 
     Actuators  19  and  20  are arranged in a partially overlapped, slidable relationship. Referring now to  FIGS. 6, 11 and 12 , actuators  19  and  20  overlie base  14  and are in contact with top base surface  15 . Top surface  21  of actuator  19  is in contact with bottom surface  26  of actuator  20  in the area surrounding the ports  24  and  28 . The two actuators are biased in a normally closed position, with the exterior end portion of each actuator biased away from the center axis of the device and the interior end portion of each actuator, which is positioned on an opposite side of the axis relative to its associated exterior end portion, biased toward the center axis of the device due to the force of springs  29  and  38  pushing actuators  19  and  20 . 
     The illustrated actuators  19  and  20  lie within a channel  35 , defined within base  14 . In a normal position, outer edge  23  and outer edge  27  are in register with and/or abut lips  36  and  37  of channel  35 . Spring  29 , held by pegs  39  and  40  and spring  38 , held by pegs  41  and  42 , work in concert to bias actuators  19  and  20  to their normal position. In operation, the exterior end portions of the actuators  19  and  20  may be moved toward the center axis of base port  18 , thus moving the interior end portions of the actuators away from the center axis of base port  18 , placing the device in an actuated, or open, position. Actuation stops, e.g.,  43 ,  44 ,  45  and  46 , protruding from channel  35 , may be provided to limit the lateral movement of actuators  19  and  20  from a normal position to an actuated position. In other words, by the use of stops, the springs  29  and  38  are not over-compressed. In the illustrated embodiment, faces  74  and  76  of cuboid stops  43  and  44  stop actuator lateral/inward movement by engaging the longer inside edges of stop ports  72  and  73 , respectively. Faces  75  and  79  of cuboid stops  43  and  44  engage the shorter inside edges of stop ports  72  and  73  to prevent misalignment of actuators  19  and  20  through their actuated movement in use. 
     Referring now to  FIGS. 2 and 6 , actuator ports  24  and  28  define, respectively, first and second bearing latch edges  47  and  48 . When in a normal position, bearing latch edges  47  and  48  together define a partial annulus that, in use, engages an annular bearing surface  49  of a warewasher liquid supply shaft assembly  50 . Cover  30  overlies actuators  19  and  29  and is mounted to base  14 . Cover edge  33  removably overlaps base edge  17  and may be held on by friction. In alternative embodiments, base  14  is glued to cover  30  or cover  30  is attached to base  14  with any fastening means known the person of ordinary skill in the art, for example screws, rivets, locking pins, and the like. The exterior ends of actuators  19  and  29  extend radially outward beyond cover edge  33  and base edge  17  through slots  51 . In this way, actuator edges  22  and  27  may be manually pushed in and the alignment of the actuators maintained. 
     Referring now to  FIGS. 7 and 8 , a liquid supply shaft assembly  50  is disclosed, which assembly includes a liquid supply tube  61  having a liquid inlet end  52 , a liquid outlet end  53  an inner tube surface  54  and an outer surface  55 . A sleeve bearing  60  includes a first end  56 , a second end  57 , an exterior surface  49 , and an inner surface  58 . First end  56  is aligned with and abuts liquid outlet end  53  of tube  61 . A hollow axle shaft  59  removably fixes sleeve bearing  60  to liquid supply tube  61 . Liquid inlet end  52  includes a means to attach end  52  to an inlet liquid supply line in a warewash machine (e.g., end  52  has a threaded surface for screw-like attachment to a correspondingly threaded female port in a warewash machine). Ends  56  and  57  of sleeve bearing are of greater diameter than the diameter of surface  49 , thus forming two annuli demarcating surface  49 . Ends  56  and  57  are preferentially chamfered, thus allowing the device to operate smoothly as will be described in more detail below. 
     Hollow axle shaft  59  includes end  63 , end  64 , an inner tube surface  65 , a supply shaft outer surface engagement region  66  proximate to first end  63  and a sleeve bearing region  67  positioned between supply shaft outer surface engagement region  66  and second axle shaft end  64 . An annular groove  68  may be provided between supply shaft outer surface engagement region  66  and sleeve bearing engagement region  67 . Annular groove  68  is shaped to receive an O-ring, which in assembly provides a substantially liquid-tight seal between axle shaft  59  and liquid supply tube  61 . In assembly, shaft end  63  is pushed through the ends of sleeve bearing  60  such that supply shaft outer surface engagement region  66  is positioned within and in contact with supply shaft inner tube surface  54  and bearing region  67  is positioned within the sleeve bearing  60 . Sleeve bearing  60  may be manufactured of a substantially low-friction material, for example, a plastics, a fluoropolymer, a polytetrafluoroethylene; or, in another embodiment an ultra-high molecular weight polyethylene; or a nylon. Sleeve bearing  60  will rotate freely about the bearing region  67  of the shaft  59 . 
     Referring now to  FIGS. 3, 4, 9 and 10 , in an embodiment, a combination of warewash machine arm  10  mounted on liquid supply shaft assembly  50  is shown. Screws  69  and  70  pass through arm body  10  and secure arm body  10  to base  14 . A gasket  71  may be mounted in register with mount opening  13  to provide a substantially watertight seal between arm body  10  and base  14 . Other sealing arrangements could be used. 
     End  64  of the supply shaft assembly includes an chamfered edge  77 . To install a warewash arm on the supply shaft assembly  50 , the central opening of the arm mount or hub is axially moved onto the end  64  causing the chamfered edge  77  to engage the partial annulus formed by bearing latch edges  47  and  48 , pushing latch edges  47  and  48  outward slightly. When the latch edges have fully passed the chamfered edge  77  and the end lip of the sleeve bearing, springs  29  and  38  return the actuators to a closed position, causing bearing latch edges  47  and  48  to contact sleeve bearing outer surface  49 , holding the warewash arm onto the liquid supply shaft assembly in a manner that permits the arm to rotate via the permitted rotation of the sleeve bearing  60 . To remove the arm from the liquid supply assembly, the actuators are manually pushed inward as described above so that latch edges  47  and  48  move outward far enough to clear the end lip of the sleeve bearing to permit the arm mount to move axially off of the liquid supply shaft assembly. Notably, the action that enables arm removal is a simple, ergonomic squeezing operation of the diametrically opposed actuators that can be performed with one hand. 
     The port  18  in base  14  is defined in part by a tapered edge  72  per  FIG. 9 . Chamfered edge  77  is substantially flush with tapered edge  72  and in alignment with mount opening  13 . In this manner, liquid supply shaft assembly  50  cannot pass into liquid space  11  of arm body  10 . 
     A warewash machine including the foregoing liquid supply shaft assembly  52  and the described warewash machine arm and associated mount facilitates straightforward and convenient installation and removal of the arm for cleaning and/or replacement. The above mechanism allows a rotating rinse arm to be easily attached and removed by the user, without the use of tools, for cleaning or replacement. The user can install the arm by either pushing the rinse arm hub mechanism onto a supply stem or by depressing two opposing buttons on the hub mechanism to install on the supply stem. To remove the arm the user depresses two opposing buttons on the hub mechanism and removes the arm off of the supply stem. 
     This device allows for advantages over other quick latching-type mechanisms. The mechanism is very low profile allowing for a quick-latch mechanism in a very tight space. More consistent spinning and improved life the mechanism is provided by separating the spinning from the latching. Rather than have the latches both hold the arm in and be the bearing surface for spinning, the described mechanism has a sleeve bearing that is attached to the supply shaft and that provides for the spinning, and the mechanism latches only have to hold the rinse arm to the bearing. The rinsing fluid enters the rinse arm beyond the latching mechanism and is somewhat separated from the mechanism to limit the interaction of the fluid and the mechanism. The mechanism housing incorporates features that both act as a positive stop for the latching action and provide for support for the mechanism to allow correct operation even when subjected to outside stress. 
     Referring now to  FIGS. 13 and 14 , a combination rinse arm and wash arm arrangement is shown, where the contemplated arrangement utilizes a downwardly extending supply shaft assembly  61 ,  60 ,  59  on which the rinse arm  10  is mounted toward the bottom via the arm mount described above. Above the rinse arm  10 , a wash arm  100  is also mounted along the supply shaft assembly. The wash arm  100  includes an elongated arm body  102  with an upper opening  104  in which a wash arm mount hub  106  is located, the mount hub  106  secured to a lower portion of the arm body  102  via screws  108 . A wash arm bushing  110  sits within the mount hub  106 . As shown, a bottom portion  112  of the bushing  110  protrudes from a lower opening of the arm body  102  slightly and provides a downwardly facing annular bearing surface  114  that sits atop the upper surface of the top cover  30  of the rinse arm mount. The bushing  110  may be formed of a PTFE or other low friction material to provide a low friction interface between the wash arm and rinse arm, given that the wash arm is supported on the shaft assembly by the rinse arm. This arrangement facilitates ease of rotation of both the wash arm and the rinse arm as desired. When the rinse arm is released and removed, the wash arm is no longer held on the supply shaft assembly  50  and can also be removed. 
     The arrangement of  FIGS. 13 and 14  also shows an additional bearing feature that may be incorporated into the arrangement. Specifically, the axle shaft  59  of the supply shaft assembly includes one or more fluid passages  122  through its tubular wall in the region that aligns with the sleeve bearing  60 . The passages  122  act as bleed ports through which rinse fluid may travel, as per arrow  124 , to reach the interface of the external surface of the axle shaft  59  and the internal surface of the sleeve bearing  60 , thereby lubricating the interface of the two cylindrical surfaces to improve the spinning characteristic of the sleeve bearing  60  about the axle shaft  59 . The axle shaft  59  may also include a recessed peripheral groove  126  in which the passages  122  are located to facilitate peripheral flow of rinse fluid about the axle shaft  59  to assure that the rinse fluid reaches the full peripheral extent of the interface of the two cylindrical surfaces. In addition to acting as an interface lubricant, the rinse fluid delivered through the passages  122  also helps to flush out the bearing interface to reduce the likelihood that food soils will migrate into and/or build up within the interface, thereby assuring a continually strong and unhindered rotating characteristic of the sleeve bearing  60  over the long term. 
     It is to be clearly understood that the above description is intended by way of illustration and example only, is not intended to be taken by way of limitation, and that other changes and modifications are possible. For example, while the primary embodiment shown above depicts the shaft and arm arrangement in a downwardly extending or hanging orientation (e.g., as in the case of an upper rinse arm and upper wash arm of a machine), the same shaft and arm arrangement can be used in an upwardly extending orientation (e.g., in the case of a lower rinse arm and lower wash arm of a machine).