Patent Publication Number: US-7584899-B2

Title: HVAC controller

Description:
This application is a continuation of U.S. patent application Ser. No. 10/791,043 filed Mar. 1, 2004. 

   FIELD OF THE INVENTION 
   The present invention relates generally to the field of controllers, and more particularly to HVAC controllers for controlling one or more environmental conditions of an inside space. 
   BACKGROUND OF THE INVENTION 
   Controllers are used on a wide variety of devices and systems for controlling various functions in homes and/or buildings and their related grounds. Some controllers have schedule programming that modifies device parameter set points as a function of date and/or time. HVAC controllers, for example, are employed to monitor and, if necessary, control various environmental conditions within a home, office, or other enclosed space. Such devices are useful, for example, in regulating any number of environmental conditions with a particular space including for example, temperature, humidity, venting, air quality, etc. The controller may include a microprocessor that interacts with other components in the system. For example, in many modem thermostats for use in the home, a controller unit equipped with temperature, humidity and/or other sensing capabilities may be provided to interact with a heater, blower, flue vent, air compressor, humidifier and/or other components, to control the temperature, humidity, and/or other environmental conditions at various locations within the home. For example, a sensor located within the controller unit and/or at one or more remote locations may be employed to sense when the temperature or humidity reaches a certain threshold level, causing the controller unit to send a signal to activate or deactivate one or more component in the system. 
   The controller may be equipped with an interface that allows the user to monitor and adjust the environmental conditions at one or more locations within the building. With more modem designs, the interface typically includes a liquid crystal display (LCD) panel inset within a housing that contains the microprocessor as well as other components of the controller. In some designs, the interface may permit the user to program the controller to activate on a certain schedule determined by the user. For example, the interface may include a separate menu routine that permits the user to change the temperature at one or more times during a particular day. Once the settings for that day have been programmed, the user can then repeat the process to change the settings for the other remaining days. 
   Many of these controllers have one or more push buttons located on the front of the controller. A microcontroller or the like typically receives and interprets the signals from the push buttons, and implements the desired function. It has been found, however, that some users have difficulty controlling and/or programming their controllers using such pushbuttons, particularly those users that are not familiar with modem computers and/or computer interfaces. In addition, push buttons and the supporting hardware and/or software can significant increase the cost of such controllers. As such, it would be desirable to provide a simplified and/or lower cost controller interface for an HVAC controller. 
   SUMMARY OF THE INVENTION 
   The present invention is directed at an HVAC controller with a simplified and/or lower cost user interface. In one illustrative embodiment, the HVAC controller includes two switches, a movable member, and a plurality of detents. The detents are configured to cause the two switches to be switched in a sequence when the movable member is moved. In some cases, a controller is coupled to the two switches, and may change an HVAC control parameter based on the switch sequence. 
   In some embodiments, the detents may be provided on the movable member, and a number of detent tabs may ride along the detents as the movable member is moved. The detent tabs may activate and deactivate the switches, depending on whether the detent tabs lie along a peak or valley of the detents. When more than one detent tab is provided, the detents and detent tabs may be configured such that the two switches are switched out of phase relative to one another. When so provided, both the direction and magnitude of movement of the moveable member can be detected. In some embodiments, and for detecting rotational movement, the detents are may be provided along a detent ring. 
   In some embodiments, more than one set of detents may be provided. For example, a first set of detents may be used to cause the two switches to be switched in a sequence when the movable member is moved. A second set of detents may also be provided to fix the position of the movable member at one of a series or positions. In effect, the second set of detents may be used to provide discrete stopping positions for the movable member. The discrete stopping positions may correspond to discrete “states” of the switches as the movable member moves across the first set of detents. 
   In some embodiments, the HVAC controller includes a backlight button. The backlight button may be a hinged button on a front surface of the HVAC controller, and may form a portion of an HVAC controller outer housing. The backlight button can have a surface area greater than or equal to a surface area of a display on the HVAC controller. Alternatively, or in addition to, the backlight button can have a surface area at least 2.5% of an HVAC controller outer housing cross-sectional surface area. Also described is an HVAC controller that includes a zebra strip for electrically connecting a backlight light source to a circuit board. Also described is an HVAC controller that includes a sensor circuit board that intersects and/or interlocks with a main circuit board. 
   In further embodiment, An HVAC controller includes a controller housing having a front surface, a display on the front surface, and an movable interface member disposed about the display and forming a portion of the controller housing front surface, wherein the movable member is movable relative to the display. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of an illustrative controller employing various aspects of the present invention; 
       FIG. 2  is an exploded perspective view of the illustrative controller of  FIG. 1 ; 
       FIG. 3  is a perspective view of an illustrative interface member showing an illustrative inner surface; 
       FIG. 4  is a perspective view of an illustrative detent ring showing an illustrative inner surface; 
       FIG. 5  is a rear view of an illustrative intermediate housing; 
       FIG. 6  is a perspective view of an illustrative sensor assembly in accordance with an illustrative embodiment of the present invention; and 
       FIG. 7  is an exploded view of a backlight assembly. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The following description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. Although examples of construction, dimensions, and materials are illustrated for the various elements, those skilled in the art will recognize that many of the examples provided have suitable alternatives that may be utilized. 
   As used herein, the term “control parameter” may include any parameter or setting useful when operating an HVAC controller such as, for example, a temperature control setting, a humidity control setting, a time control setting, an actual temperature reading, an actual time reading, an actual humidity reading, a schedule parameter, and/or the like. 
     FIG. 1  is a front view of an illustrative controller  10  employing various aspects of the present invention. Controller  10 , illustratively a wall-mounted thermostat, includes a base housing  12 , a front surface  20  including a display or interface (i.e., LCD) panel  14 , and an interface or control member  16 . In an illustrative embodiment, the display panel  14  and a backlight button  18  form a portion of the front surface  20 . The backlight button  18  is shown adjacent and below the display panel  14 , however the backlight button  18  and display panel  14  can be located in any useable location and assume any suitable configuration relative to one another, as desired. The base housing  12 , front surface  20  and interface member  16  form an outer housing for the controller  10 . The controller  10  is shown having a circular form, however, the controller  10  can have any useable regular or irregular form such as, for example, square, rectangle, oblong, triangular, or any other form, as desired. 
   The base housing  12  is defined by a base housing perimeter  11 . In an illustrative embodiment, the base housing  12  is adjacent to a mounting surface (not shown). The base housing  12  has a base housing surface area defined by the base housing perimeter  11 . As used herein, the term “surface area” is defined as a planar cross-sectional surface area. In some embodiments, the surface area of the base housing  12  can be from 1 in 2  to 40 in 2 , or 5 in 2  to 20 in 2 , or 7 in 2  to 15 in 2 , as desired. However, it should be recognized that the surface area of the base housing  12  can have any desired size. 
   The front surface  20  of the controller  10  is defined by a front surface perimeter  21 . In the illustrative embodiment, the front surface  20  is shown having a circular shape, however, the front surface  20  can have any useable regular or irregular shape such as, for example, square, rectangle, oblong, or triangular. The front surface  20  can have a generally planar or non-planar surface. In an illustrative embodiment, the front surface  20  has a generally planar or generally convex surface. In the illustrative embodiment, the front surface  20  is located generally at the center of the controller  10 , however, the front surface can be located at any useable position on the controller  10 . 
   In the illustrative embodiment, the display panel  14  is defined by a display panel perimeter  13 . The display panel  14  can have any useable regular or irregular shape, as desired. The display panel  14  has a display panel surface area within the display panel perimeter  13 . In some embodiments, the surface area of the display panel  14  can be from 0.25 in 2  to 5 in 2 , or 0.5 in 2  to 2 in 2 , or 0.75 in 2  to 1 in 2 , as desired. However, it should be recognized that the surface area of the display panel  14  can have any desired size. 
   A separate display retainer and switchable backlight (see  FIG. 7 ) disposed behind the display panel  14  may be used to illuminate the display panel  14  at night, and to increase the visibility of the display panel  14  during daytime use. A backlight button  18  may be used to operably activate and/or deactivate the switchable backlight. Alternatively, or in addition, the switchable backlight can be activated by moving the interface member  16  when displaying and/or adjusting a display parameter. The switchable backlight can deactivate following the expiration of a specific time interval. 
   The backlight button  18  is defined by a backlight button perimeter  19 . The backlight button  18  can have any useable regular or irregular shape, as desired. The backlight button  18  has a backlight button surface area within the backlight button perimeter  19 . In some embodiments, the surface area of the backlight button  18  can be from 0.25 in 2  to 5 in 2 , or 0.5 in 2  to  2  in 2 , or 0.75 in 2  to 1 in 2 , as desired. However, it should be recognized that the surface area of the backlight button  18  can have any desired size. In an illustrative embodiment, the backlight button  18  has a surface area that is greater than or equal to the display panel  14  surface area. In some illustrative embodiments, the backlight button  18  has a surface area 10% greater, 20% greater, 30% greater or more than the display panel  14  surface area. In further illustrative embodiments, the backlight button  18  has a surface area of at least 1%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15% or more of the base housing  12  surface area. 
   The backlight button  18  can be generally co-planar with the controller outer housing or front surface  20  and form a portion of the outer housing or front surface  20 . In some embodiments, the backlight button  18  is hinged to a portion of the controller  10  outer housing or front surface  20 , if desired. In an illustrative embodiment, the backlight button  18  is hinged to the front surface  20  and forms a portion of the front surface  20  and outer housing. The backlight button can be hinged adjacent to the display panel  14 , for example. 
   The interface member  16  is shown having an annular shape, however, the interface member  16  can have any useable regular or irregular shape as desired. In the illustrative embodiment, the interface member  16  forms the portion of the outer housing between the base housing  12  and the front surface  20 . The interface member  16  is defined by an interface inner perimeter  15  between the front surface  20  and the interface member  16 , and an interface outer perimeter  17  between the interface member  16  and the base housing. In the illustrative embodiment, the interface member  16  can be rotated in a clockwise and/or counter-clockwise manner. 
   The interface member  16  is configured to modify the information displayed on the display panel  14 . For example, and in one illustrative embodiment, the interface member  16  may display the value of a parameter of the controller  10 , such as time, temperature, one or more set points, or any other suitable parameter. The interface member  16  can then be rotated to effect a change in the parameter on the display panel  14 . In another illustrative embodiment, the display panel  14  can initially display information regarding a first parameter such as, for example, a time or a temperature. Upon movement of the interface member  16 , the display panel  14  can display information regarding a second parameter such as, for example, a time or temperature set point. The interface member  16  can then be further moved to effect a change in the second parameter. For example, the interface member can be moved in a first direction to increase the value of the displayed second parameter or be moved in a second direction opposite the first direction to decrease the value of the displayed second parameter. In an illustrative embodiment, the interface member  16  has an annular or circular form and the movement is a rotational movement. However, in other embodiments, the interface member may be moved along an elliptical, linear or along any other desired path, as desired. 
   The interface member  16  can be removable from the controller  10 , if desired. Removal of the interface member  16  by a user aids in cleaning the controller  10  and interface member  16 . In addition, with the interface member  16  removed the controller  10  still can fulfill all the requirements for environmental protection such as static discharges. The interface member  16  can be formed of a rigid thermoplastic material. The interface member  16  can be formed from a same material as the material forming the controller housing  10  and/or base housing  12  and/or front surface  20 . The interface member  16  can have a smooth surface. 
     FIG. 2  is an exploded perspective view of the illustrative controller  10  shown in  FIG. 1 . A base housing  12  may be provided. The base housing  12  may be mounted to a mounting surface such as a wall. A controller section, which is generally shown at  50 , is disposed on or adjacent to the base housing  12 , and in some embodiments, a connector  23  may provide one or more signal connections between the base housing  12  and the controller section  50 . 
   The controller section  50  can include electronics useful for the operation of the controller  10 . In an illustrative embodiment, the controller section  50  includes a main circuit board  51 . A display panel  14  may be attached to the main circuit board  51  via a display retainer housing  68 , as further described below. Two switches  56  and  57  can also be disposed on or adjacent to the main circuit board  51 . The two switches  56  and  57  may be electrically connected to electronics on the main circuit board  51 , and may form the basis for adjusting one or more control parameters of the controller  10 . More than two stitches can be used, if desired. The switches  56  and  57  can be mechanical switches, optical switches, or any other suitable switches, as desired. The control of switches  56  and  57  is described further below. A backlight switch  58  can also be disposed on or adjacent to the main circuit board  51 . The backlight switch  58  can be mechanically coupled to backlight button  18  through a backlight button post  48  (see  FIG. 5 ). The backlight switch  58  may be used to operably activate and/or deactivate the switchable backlight of the display panel  14 . 
   A sensor  53 , such as a temperature sensor, a humidity sensor, a gas sensor, or the like, may also be electrically coupled to the main circuit board  51 . The sensor  53  is shown spaced away from the main circuit board  51 , which in some cases, may be helpful in achieving a more accurate reading. The sensor  53  is disposed on a sensor circuit board  52 , which as better shown in  FIG. 6 , intersects and/or interlocks with the main circuit board  51 . 
   An intermediate housing  40  is disposed on or adjacent to the controller section  50 . The intermediate housing  40  can form at least part of the front surface  20  of the controller  10 . In the illustrative embodiment, the intermediate housing  40  includes a display aperture defined by display perimeter  13 . The display aperture may allow a user to see the display panel  14  of the controller section  50 . A backlight button  18  forms a portion of the intermediate housing  40  and/or front surface  20 . In the illustrative embodiment, the backlight button  18  can be attached to the intermediate housing  40  via a hinge. 
   The intermediate housing may also include one or more detent tabs (e.g.  44 ,  46 ). The detent tabs  44  and  46  can be formed from metal or any other suitable material. The detent tabs  44  and  46  can be configured to engage corresponding outer and inner detent rings, respectively, of a detent ring housing  26  (see  FIG. 4  below). The detent tabs  44  and  46  may move toward the back base housing  12  when engaging a peak of a detent along the detent ring housing, and away from the back housing  12  when engaging a valley of a detent along the detent ring housing. 
   Detent tab  44  may perform a different function than detent tab  46 . For example, detent tab  44  may be used to selectively fix the position of the detent ring housing  26  at defined incremental positions. In contrast, detent tab  46  may be used to selectively activate switch  56 , based on the current incremental position of the detent ring housing  26 . 
   The detent ring housing  26  is disposed on or adjacent to the intermediate housing  40 . As better shown in  FIG. 5 , the detent ring housing  26  may include an inner detent ring  28  and an outer detent ring  29  both facing the intermediate housing  40 . The inner detent ring  28  is adapted to engage detent tab  46  of the intermediate housing  40 . The outer detent ring  29  is adapted to engage detent tab  44  of the intermediate housing  40 . 
   The detent ring housing  26  also includes an interlock surface  24 . The interlock surface  24  is configured to engage an interface member  16 , and couple the detent ring housing  26  to the interface member  16 . In the illustrative embodiment, the interlock surface  24  is a grooved surface with the interface member  16  having a corresponding grooved mating surface  38 . 
   The interface member  16  can form a portion of the outer housing of the controller  10 . The interface member  16  can have an interface inner perimeter  15  and an interface outer perimeter  17 . The grooved mating surface  38  can be disposed on or in the inner surface  37  of the interface member  16 , and may be adapted to engage the interlock surface  24  of the detent ring housing  26 . The interface member  16  can be rotated by a user of the controller  10 . When rotated, the interface member  16  moves the detent ring housing  26  relative to the detent tabs  44  and  46  of the intermediate housing  40 . Detent tab  44  may selectively fix the position of the detent ring housing  26  and thus the interface member  16  at defined incremental positions. Detent tab  46  may be used to selectively activate switch  56 , based on the current incremental position of the interface member  16 . 
     FIG. 3  is a perspective view of an illustrative interface member  16  showing inner surface  37 . The grooved mating surface  38  may include four separate grooved mating surfaces  38 . The four separate grooved mating surfaces  38  may be configured to engage a different part of the interlock surface  24  of the detent ring housing  26 . In the illustrative embodiment, the interface member  16  has an annular and concave shape as shown. 
     FIG. 4  is a perspective view of an illustrative detent ring housing  26  having an inner detent ring  28  and an outer detent ring  29 . The inner detent ring  28  has a first detent pattern and the outer detent ring  29  has a second detent pattern. The inner detent ring pattern is used move detent tabs  46   a  and  46   b  of the intermediate housing  40  toward and away from the main control board  51 . As the detent tabs  46   a  and  46   b  move toward and away from the main control board, they each activate and/or deactivate the corresponding switches  56  and  57 . By noting the sequence of activation of the switches  56  and  57 , the controller  10  can determine the direction and magnitude of movement of the interface member  16 . The outer detent ring  29  pattern can work in cooperation with detent tabs  44   a  and  44   b  of the intermediate housing  40  to selectively fix the position of the interface member  16  at defined incremental positions. The outer detent ring pattern may work in cooperation with the inner detent ring pattern so that the defined incremental positions correspond to desired locations or “states” along the inner detent ring pattern. 
     FIG. 5  is a rear view of an illustrative intermediate housing  40 . A set of outer resilient detent tabs  44   a ,  44   b  are shown generally at a three o&#39;clock and a nine o&#39;clock position on the intermediate housing  40 . The outer resilient detent tabs  44   a  and  44   b  are adapted to engage and ride over the outer detent ring  29  of  FIG. 4 , and selectively fix the position of the interface member  16  at defined incremental locations when the outer resilient detent tabs  44   a  and  44   b  come to rest between two detents. 
   A set of inner resilient detent tabs  46   a ,  46   b  are also shown, generally at a twelve o&#39;clock and a six o&#39;clock position on the intermediate housing  40 . In an illustrative embodiment, a first inner resilient detent tab  46   a  and second inner resilient detent tab  46   b  are positioned relative to one another such that they operate out of phase while riding over the inner detent ring  28 . In this configuration, the first inner resilient detent tab  46   a  and second inner resilient detent tab  46   b  can operate to indicate both direction and magnitude of movement of the detent ring  26  relative to the intermediate housing  40 . 
   For example, the inner resilient detent tabs  46   a ,  46   b  can be about 90 degrees out of phase relative to detents of the inner detent ring  28 . Also, the outer detent ring  29  may be configured relative to the inner detent ring  28  to provide four selective stopping states for each period of the inner detent ring pattern such that the inner resilient detent tabs  46   a ,  46   b  can obtain four sequential states (first tab:second tab) when rotated in a clockwise manner. These four sequential states may be, for example: off:off, off:on, on:on, and on:off (where “on” indicated tab deflection and “off” indicates no tab deflection). When rotated in a counter-clockwise manner, the sequence of states may be: off:off, on:off, on:on, off:on. Thus, the state of the switches  56  and  57  on the main circuit board  51  can be used to determine the direction and magnitude of rotation of the interface member  16 , and in some cases, to adjust a parameter accordingly. 
     FIG. 5  also shows a backlight button post  48  extending away from the backlight button  18 . In the illustrative embodiment, the backlight button post  48  engages the backlight switch  58  (see  FIG. 2 ) on the main circuit board  51 . 
     FIG. 6  is a perspective view of an illustrative sensor  53  in accordance with an illustrative embodiment of the present invention. In the illustrative embodiment, a sensor  53  is provided, but is spaced away from the main circuit board  51 . The sensor  53  can be any sensor such as, for example, a temperature sensor, a humidity sensor, a gas sensor, or the like. To space the sensor away from the main circuit board  51 , the sensor  53  can be disposed on a sensor circuit board  52 . The main circuit board  51  can extend along a first plane, and the sensor circuit board  52  can extend along a second plane that intersects the first plane. In the illustrative embodiment, the sensor circuit board  52  intersects and/or interlocks with the main circuit board  51 . The main circuit board includes a protrusion  54  that extends away from the main circuit board  51 . The sensor circuit board  52  is adapted to extend around the protrusion  54  and sometimes interlock therewith. In some embodiments, the protrusion  54  may form one or more slots between the protrusion and the main circuit board. The sensor circuit board  52  may then be configured to slip into the one or more slots to engage and sometimes interlock therewith. 
   The sensor circuit board  52  may include one or more signal traces to provide electrical signals to/from the sensor. The one or more signal traces can be electrically connected to corresponding signal traces on the main circuit board with solder or the like, as shown. While only one sensor  53  is shown, it is contemplated that more than one sensor may be provided on the sensor circuit board  52 , if desired. 
     FIG. 7  is an exploded view of a backlight assembly. The illustrative backlight assembly includes a display retainer housing  68 . The display retainer housing  68  is configured to support and retain a display panel  14 , such as an LCD display panel. The display retainer housing  68  may include one or more support legs  65  that are configured to engage a corresponding set of notches or holes  55  in the main circuit board  51 . However, this is not required in all embodiments. 
   The display panel  14  can include a light guide plate  64 , if desired. The light guide plate  64  may help distribute light across the display panel  14  from one or more light sources  63 . The one or more light sources  63  may include any suitable light source, such as a light emitting diode (LEDs). The light guide plate  64  and one or more light sources  63  may be formed as a single unit using, for example, an injection molding process. Alternatively, the light guide plate  64  and one or more light sources  63  may be formed as separate elements and then connected together by adhesive or other suitable bonding process. The light guide plate  64  may be formed of any suitable transparent material including, for example, polycarbonate, acrylic, styrene acrylonitrile thermoplastic, acrylonitrile butadiene styrene (ABS), etc. 
   The dimensions of the light guide plate  64  can also be selected to control the uniformity and brightness of light rays as they pass across the backside of the display panel  14 . In certain embodiments, for example, the thickness of the light guide plate  64  can be varied to adjust the amount or orientation of light rays reflected towards the backside of the display panel  14  in order to provide greater or less illumination to particular locations of the display panel  14 . 
   The retainer housing  68  may have a slot  62  that is configured to receive an elastomeric zebra-strip  61 . The one or more light sources  63  can have one or more light source leads  60  that extend into the slot  62 . In the illustrative embodiment, the one or more light source leads  60  extend along the bottom surface of the light guide plate  64  to engage the zebra-strip  61 . The zebra-strip  61  electrically connects the light source leads  60  that extend into the slot  62  to leads  59  on the surface of the main circuit board  51 . The zebra-strip  61  may include several electrically conductive filaments therein that contact the circuit board leads  59  and light source leads  60  when compressed within the slot  62 . In certain embodiments, the slot  62  can be dimensioned to tightly receive the elastomeric zebra-strip  61 , but this is not required in all embodiments. 
   Having thus described the several embodiments of the present invention, those of skill in the art will readily appreciate that other embodiments may be made and used which fall within the scope of the claims attached hereto. Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size and arrangement of parts without exceeding the scope of the invention.