Abstract:
A mixer valve includes a rotational assembly for selecting a temperature of the water up to a maximum temperature. The rotational assembly includes a selectable “comfort” temperature indicator, that can be set independently of the maximum temperature, and does not affect the maximum temperature. The valve also includes check valves for preventing cross flow between the hot and cold pipes. A check valve insert is provided which includes a shutoff for the water flow when removing the check valve for service. The shutoff and removal of the check valve can be effected with a single tool.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 60/679,168 filed May 9, 2005. 
    
    
     STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to mixing valves. More particularly it relates to thermostatic mixing valves with improved access to check valves and filter screens and improved settings for comfort temperatures. 
     Thermostatic mixing valves can provide a source of water having a desired temperature and can maintain the desired water temperature substantially constant once set. Such devices are well known in the art. See e.g. U.S. Pat. No. 6,279,604 and U.S. patent application publication 2004/0000594. Typically, the desired water temperature is obtained by controlling the relative proportions of hot and cold water admitted to a mixing chamber and adjusting the relative proportions to maintain the desired water temperature substantially constant. 
     To prevent the temperature from being set at a temperature that risks scalding, a temperature stop is typically provided on the mixing valve. The valves often also include a method for setting a lower “comfort” level. 
     To prevent cross flow between the hot and cold input lines, check valves can be provided between the hot and cold water supplies and the mixer valves. Also, screens can be provided to avoid debris from clogging the valve interior. 
     While thermostatic mixing valves are known in the art, these known devices suffer from a number of disadvantages. For example, in some prior art devices, when the comfort level is selected, the maximum temperature selection is determined by a fixed increment therefrom. In any event, to properly maintain the valve, the check valves and associated screens need to be periodically cleaned. This process can require the use of a number of tools, requires some skill, and can be time consuming. 
     Therefore, there remains a need for an improved thermostatic mixer valve in which the check valves and screens are easily and quickly cleaned. Furthermore, there remains a need for an improved thermostatic mixer valve that mechanically provides a user selectable comfort level independent of the maximum temperature level. 
     SUMMARY OF THE INVENTION 
     In one aspect, the present invention provides a mixing valve comprising a valve body having a check valve receptacle coupled to an inlet water passage and also an outlet water passage, and a check valve insert sized and dimensioned to be received in the check valve receptacle. The check valve insert has a stop body with a shutoff element and a check valve sized and dimensioned to be received in the stop body, wherein the stop body is selectively movable in the receptacle to position the shutoff element to decouple the inlet water passage from the outlet water passage. When so positioned, the check valve is selectively removable from the stop body for service. 
     In preferred forms, the stop body and check valve each include a receptacle sized and dimensioned to receive a single tool, such that the water flow can be deactivated and the check valve removed with the selected tool. 
     In another aspect of the invention, an assembly for setting an output temperature for a thermostatic mixer valve is provided. The assembly includes a thermostatic mixing cartridge having an undercap, an overcap including a first detent member, and a rotational stem adaptor coupled between the undercap and the overcap and having a second detent member. The first detent member and the second detent member interact to provide a comfort temperature setting. 
     In a preferred form of the invention, the undercap includes a maximum stop temperature tab. The rotational stem adaptor includes a tab for mating with the maximum stop tab to limit the output temperature to the selected maximum. 
     In another preferred form, the undercap can include a first plurality of teeth, and the overcap can include a second plurality of teeth that mate with the first plurality of teeth. 
     In another preferred form, the first detent member can be a ramp. The second detent member can be a flexible tab. 
     Thus, the present invention provides improved methods and apparatuses for maintaining or servicing check valves in a mixing valve, as well as improved means for selecting a comfort level temperature when the valve is a thermostatic mixing valve. 
     These and still other advantages of the present invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there are shown preferred embodiments of the invention. Such embodiments do not represent the full scope of the invention, and reference is made therefore, to the claims herein for interpreting the full scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially exploded perspective view of a valve of the present invention, illustrating the thermostatic cartridge assembly and sealing gaskets; 
         FIG. 2  is a partial view of the valve of  FIG. 1 , illustrating the drive lid for the service stop in the closed position; 
         FIG. 3  is a view taken along the line  3 - 3  of  FIG. 1 , illustrating the check valve insert in the open flow position; 
         FIG. 4  is the same view as  FIG. 2 , but illustrating the service stop drive in the open position, allowing for the removal of the check valve; 
         FIG. 5  is a view taken along the line  3 - 3  of  FIG. 1  illustrating the check valve insert in the closed flow position; 
         FIG. 6  is a view taken along the line  3 - 3  of  FIG. 1  illustrating the check valve removed from the valve body for service; 
         FIG. 7  is a view similar to  FIG. 1 , but with temperature setting assembly exploded; 
         FIG. 8  is an exploded view of the bottom of the stem adaptor of  FIG. 7  received in the bottom of the detent cap of  FIG. 7 ; 
         FIG. 9  is a view taken along the line  9 - 9  of  FIG. 1 , illustrating the relative positions of the components at a maximum temperature; 
         FIG. 10  is a view taken along the line  9 - 9  of  FIG. 1 , illustrating the relative positions of components when the temperature is below the comfort level; and 
         FIG. 11  is a view taken along the line  9 - 9  of  FIG. 1 , illustrating the relative positions of components when the comfort level is being reset. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures, a thermostatic mixer valve  10  includes a valve body  12  having cold and hot water inlets  14  and  16  respectively, and upper and lower water outlets  18  and  20  respectively. Check valve inserts  22  and  24  providing check valves (and filter screens) for each of the hot and cold water inlets  16  and  14  are received in check valve receptacles (service stop receptacles)  49  provided in the valve body  12 . The valve body  12  further includes a cartridge chamber  26  for receiving a thermostatic cartridge assembly  27 , including both a thermostatic mixer cartridge  36 , and a temperature setting assembly  74  adapted to receive a knob or other actuator for selecting a temperature level. 
     The cartridge  36  includes cold and hot water inlets  28  and  30  and associated sealing gaskets  32  and  34  which are received in the valve body  12 , and adjusts the temperature of the water supplied to the outlets  18  and  20  based on a position selected by the temperature setting assembly  74  in a manner known in the art. While a number of thermostatic mixer valve cartridges could be used in the present invention, one such cartridge is disclosed in U.S. patent application publication 2004/0000594, which is hereby incorporated herein by reference for its description of such devices. When using the described cartridge, the cartridge can be rotated one hundred and eighty degrees to reposition the hot and cold inlets, thereby allowing a user to account for errors in plumbing the pipes and various other situations in which the hot and cold inputs have been reversed. 
     Referring now to  FIGS. 2 and 3 , the check valve insert  24  is inserted in a check valve receptacle  49 . The check valve receptacle  49  is sized and dimensioned to receive the check valve insert  24 , and includes an upper portion  53  that is threaded on the inside surface. Access ports are provided from the receptacle  49  to a water out passage  64  and a water in passage  66 , such that water flows from the inlets  14  and  16  into the water passage  66  to the check valves  60 , and out the water passage  64  to the cartridge  36  in normal operation. 
     Referring still to  FIG. 3 , the check valve insert  24  includes a service stop body  56  and a check valve  60 , which is received in the service stop body  56 . The service stop body  56  includes an upper portion with a radially-extending lip  68  that is threaded to mate with the upper portion  53  of the check valve insert  24 , and a shutoff disc  70  at the opposing end in the receptacle  49 . The lip  68  is positioned a distance from the top of the body  56  selected to locate the shutoff disc  70  to decouple the water inlet passage  66  from the water outlet passage  64  when servicing the check valve  60  as described below. To assure appropriate sealing, the shutoff disc  70  includes a rubber o-ring  71 . An inner surface  73  of the upper portion of the body  56  is also threaded to receive the check valve body  58 . 
     Referring still to  FIG. 3 , the check valve  60  is received into a check valve body  58  having a threaded upper portion  61  that mates with the threaded inner surface  73  of the upper portion of the service body  56 , and a filter screen  62 . A receptacle  54  is substantially centered in the check valve body  58  and is sized and dimensioned to receive a driving tool such as a ⅜″ socket driver for threading the check valve body  58  into and out of the service body  56 . 
     Referring still to  FIG. 3 , and again also to  FIG. 2 , the service stop body  56  includes a hinged drive lid  48  that is coupled to the top of the service stop body  56  by a hinge  51 . The drive lid  48  includes a receptacle  50 , substantially centered in the drive lid  48 , and also sized and dimensioned to receive the driving tool described above. A bracket  52  coupled to the valve body  12  extends over the edge of the check valve receptacle  49 , and is positioned to interact with the radially-extending lip  68  from the service stop body  56  to limit motion of the service body  56  from the receptacle  49  for service. Referring now to  FIG. 4 , when the lid  48  is pivoted along hinge  51 , the receptacle  54  in the check valve  60  can be accessed, and the tool inserted to remove the check valve body  58  and check valve  60 . 
     To access the check valve  60  for service, the driving tool is inserted into the receptacle  50  in the drive lid  48  and the service stop body  56  is threaded counter-clockwise (upward) along the upper portion  53  of the check valve insert receptacle  49  until the lip  68  reaches the bracket  52 , moving the check valve insert  24  from the position shown in  FIGS. 2 and 3  to that shown in  FIGS. 4 and 5 . When the bracket  52  is reached, the shutoff disk  70  and associated rubber o-ring  71  are positioned in the check valve receptacle  49  to decouple the water input passage  66  from the water output passage  64 , thereby preventing water flow into the receptacle  49  and effectively shutting off the valve  10 , as shown in  FIGS. 4 and 5 . 
     When the valve is shut off, the check valve  60  and associated filter screen  62  can be removed as shown in  FIG. 6  by inserting the same driving tool that was used to move the service stop body  56  into the receptacle  54  in the check valve  60 . By providing the same receptacle in each of the service stop body  56  and check valve body  58 , only one tool is required to remove the check valve body  58 . After service is complete, the driving tool is again used to re-insert the check valve body  58  into the service stop body  56 , and to drive the service stop body  56  back into the receptacle  49 , and therefore to the position shown in  FIG. 3 . 
     Referring now to  FIG. 7 , the thermostatic cartridge  36  includes a drive spindle  37  and undercap  29  to which the temperature setting assembly  74  is connected. The temperature setting assembly  74  includes a rotational stem adaptor  38 , overcap  40 , a wave compression spring  42  and a retaining nut  44 . The undercap  29  of the thermostatic cartridge  36  further includes a plurality of teeth  31  extending radially around the circumference of the cartridge  36 , and which mate with teeth  41  in the overcap  40 . A pair of rotational stop tabs  33  and  35  are provided on the undercap  29  coupled to the thermostatic mixer cartridge  36  to provide a minimum and a maximum temperature position for the temperature setting assembly  74 , and therefore to limit the rotation of the assembly and the temperature of water obtained from the valve  10 . 
     The stem adaptor  38  is received between the detent cap  40  and the thermostatic cartridge  36  and is maintained in position by a fastener  46  received in an aperture  47  in a distal end of the spline adaptor  38 . The retaining ring  44  is received over the overcap  40 , and is threaded into the cartridge chamber  26 . The wave compression spring  42  is positioned between the overcap  40  and the retaining ring  44 , and provides a force on the overcap  40  to maintain the overcap  40  against the drive spindle  37  of the thermostatic cartridge  36 , and to maintain the teeth  31  mated with the teeth  41 . 
     Referring still to  FIG. 7  and also to  FIG. 8 , the stem adaptor  38  includes a rotational stop tab  39  that mates with the minimum and maximum temperature tabs  33  and  35  in the cartridge  36  to provide a rotational stop of minimum and maximum temperature, and a detent member in the form of a comfort temperature tab  43 . The comfort tab  43  extends radially from the outer circumference of the adaptor  38 , and is substantially centered adjacent an elongate aperture  76  inset from the outer edge of the spline adaptor  38 . The aperture  76  allows the tab  43  to “flex” inward and outward, as described below. 
     Referring still to  FIG. 8 , the overcap  40  is substantially cylindrical in shape, including a plurality of teeth  41  extending radially outward and sized and dimensioned to mate with the teeth  31  on the cartridge  36  at a variety of possible positions. A mating detent member, here a ramp  72 , is also provided extending from an inner surface of the detent overcap  40 , and positioned a distance above the teeth  41 . When assembled, the ramp  72  interacts with the comfort temperature tab  43  on the rotational stem adaptor  38  to provide an indication to the user when the comfort position is key reached, also as described below. This is in the form of resistance to turning. However, further turning past this point is still possible. 
     Referring now to  FIGS. 9-11 , a cutaway view of the temperature setting assembly  74  taken along the line  9 - 9  in  FIG. 1  is shown as the assembly  74  is moved to varying positions. Referring first to  FIG. 9 , here the tab  39  on the rotational stem adaptor  38  is shown in contact with the maximum temperature tab  35  on the cartridge  36 , indicating that the maximum temperature has been reached. Although a number of different temperatures can be selected, a maximum anti-scald temperature of 120 degree Fahrenheit is typical. 
     Referring now to  FIG. 10 , here the temperature setting assembly  74  is shown rotated to a new position, and the comfort tab  43  is shown approaching the ramp  72  in the cap  40 . The comfort tab  43  follows the ramp  72  to a high point  78  at which the user will feel the tab  43  fall off of the ramp  72  indicating that the selected comfort temperature has been reached. As the tab  43  is moved along the ramp  72 , the aperture  76  formed in the adaptor  38  following the outer surface of the adaptor  38  allows the bottom surface of the rotational stem adaptor  38  to flex inward. Therefore, the tab  43  can move radially inward as it follows the ramp  72  and flex back out as it passes the high point  78 . The comfort tab  43  does not provide an actual “stop”, but can be moved past the comfort position if desired. Rotation would then be allowed to continue until the tabs  35  and  39  meet, as discussed above. 
     Referring now to  FIG. 11 , the relative position of the components in the temperature setting assembly  74  are shown as an adjustment to the selected comfort temperature is made. To adjust the selected temperature, a user pulls on the overcap  40  axially to remove the teeth  41  in the overcap  40  from the teeth  31  in the undercap  29  of the cartridge  36 . When the teeth are disengaged, the overcap  40  can be rotated to a new position, to reposition the ramp  72  relative to the stops  33  and  35 . When the ramp  72  is in the position selected by the user, the overcap  40  is released so that the teeth  31  re-engage with the teeth  41 . The point  78  is therefore repositioned, providing an adjustment in the selected comfort temperature, while the stop tabs  35  and  39  remain in the same orientation, thereby maintaining the selected maximum temperature irrespective of the selected comfort temperature. The wave compression spring  42  maintains a force on the detent overcap  40  to assure that the teeth  31  and  41  are engaged. 
     The invention therefore provides a number of advantages. The check valve inserts provide check valves concentric with a shut-off device, which helps to reduce the overall size of the valve. The check valves, moreover, can be serviced with a single tool, thereby simplifying maintenance of the valve. Furthermore, servicing can be done by even those with minimal plumbing skill. Further, a comfort temperature selection is provided which allows the user to select a comfort level setting without affecting the maximum temperature. 
     It will be appreciated that a variety of changes can be made to this structure without departing from the spirit or scope of the invention. For example, although a specific driving tool is described above, various other tools could also be used. Additionally, although the valve is shown and described as providing only a temperature mixing function, volume controls can also be integrated with the valve, particularly in the inlet and outlet ports. Still other modifications could be made within the scope and spirit of the invention. 
     INDUSTRIAL APPLICABILITY 
     Disclosed are mixer valves useful in shower and other bathing installations.