Refrigerator with auxiliary door opener

Abstract

A refrigeration appliance can comprise a box body, a door body, a door opener and a controller. The door opener may be attached to the cabinet and include a housing, a push rod, and a position sensor. The controller may be in operable communication with the door opener and configured to direct operation of the door opener. The door opener operation may include guiding the push rod to a retracted position, detecting that the door body is in a closed position after guiding the push rod to the retracted position, guiding the push rod forward from the retracted position after detecting that the door body is in the closed position, monitoring a sensor output at the rod load sensor while guiding the push rod forward, and outputting the sensor output at the rod load sensor. Contact with the door body is detected while monitoring the sensor output, and the push rod is stopped at the partially extended position in response to detecting the contact.

Description

Refrigerators with assisted door openers Technical Field

[0001] The present invention generally relates to an electrical appliance having a cabinet and a door. For example, the electrical appliance may include a refrigeration appliance. Background Art

[0002] Refrigeration appliances typically include a housing that defines one or more refrigerated compartments for receiving and storing food. One or more insulated, sealed doors are provided to selectively seal the refrigerated food storage compartments. Typically, the doors can be moved between a closed position and an open position by pulling the doors (such as by a handle on the door) to provide access to the food stored therein.

[0003] In some cases, for example, when the user's hands are full of groceries to be loaded into the refrigerator or stained with raw ingredients for cooking, the user may prefer to open the door without having to grasp the door or a portion of the door (such as a handle) in the user's hands. For example, the user may prefer to gently push or push the door to open it.

[0004] Past attempts to provide assisted door openers have suffered from numerous drawbacks. In particular, existing systems struggled to ensure consistent opening results over time. For example, the alignment between the door opener and the door (or portions thereof) could change as certain components (e.g., the door or seal) settle and wear. However, the features or procedures used to address these drawbacks were cumbersome or difficult. In many cases, specialized technicians were required to repair or resolve incorrect or poor opening results.

[0005] Therefore, a refrigerator having an improved device for opening a door would be useful. In particular, a refrigeration appliance having features for ensuring consistent opening results would be desirable. Additionally or alternatively, a refrigeration appliance having features for maintaining alignment between the door opener and the door (e.g., automatically or without direct user intervention) would be advantageous.

[0006] Summary of the Invention

[0007] Various aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0008] In one exemplary aspect of the present invention, a refrigeration appliance is provided. The refrigeration appliance may include a housing, a door, a door opener, and a controller. The housing may define a food storage chamber. The food storage chamber may extend laterally between a front portion and a rear portion. The front portion of the food storage chamber may define an opening for receiving food. The door may be disposed at the front portion of the food storage chamber and may be movable between a closed position and an open position to selectively seal the food storage chamber in the closed position and provide access to the food storage chamber in the open position. The door opener may be attached to the housing. The door opener may include a housing, a push rod, and a rod load sensor. The housing may be fixedly mounted to the housing. The push rod may extend through the housing toward the door and be movable relative to the housing to push the door toward the open position. The rod load sensor may be attached to the housing to detect a mechanical load on the push rod. The controller may be in operative communication with the door opener and configured to direct operation of the door opener. The door opener operation may include guiding the push rod to a retracted position, detecting that the door body is in a closed position after guiding the push rod to the retracted position, guiding the push rod forward from the retracted position after detecting that the door body is in the closed position, monitoring a sensor output at a rod load sensor while guiding the push rod forward, detecting contact with the door body while monitoring the sensor output, and stopping the push rod at a partially extended position in response to detecting contact.

[0009] In another exemplary aspect of the present invention, a method for operating a refrigeration appliance is provided. The method may include guiding a push rod of a door opener to a retracted position. The method may also include detecting that a door body is in a closed position after guiding the push rod to the retracted position, and guiding the push rod forward from the retracted position after detecting that the door body is in the closed position. The method may also include monitoring a sensor output at a rod load sensor of the door opener while guiding the push rod forward. The method may also include detecting contact with the door body while monitoring the sensor output, and stopping the push rod at the partially extended position in response to detecting the contact.

[0010] These and other features, aspects and advantages of the present invention will become more readily understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] With reference to the accompanying drawings, the specification sets forth a complete disclosure of the present invention for those skilled in the art, which disclosure enables those skilled in the art to implement the present invention, including the best embodiment of the present invention.

[0012] FIG1 provides a front elevational view of a refrigeration appliance according to an exemplary embodiment of the present invention, wherein a door of the refrigeration appliance is shown in a closed position.

[0013] FIG. 2 provides a front elevation view of the exemplary refrigeration appliance of FIG. 1 , with the door shown in an open position.

[0014] FIG3 provides a cross-sectional elevation view of the exemplary refrigeration appliance of FIG1 .

[0015] 4 provides a side cross-sectional view of an exemplary door opener according to an exemplary embodiment of the present invention that may be incorporated into an appliance such as the refrigeration appliance of FIG. 1 .

[0016] FIG5 provides a plan view of the gear set of the example door opener of FIG4.

[0017] FIG6 provides a side cross-sectional view of a portion of the example door opener of FIG4.

[0018] FIG7 provides an enlarged side cross-sectional view of a portion of the example door opener of FIG4.

[0019] FIG. 8 provides a plan view illustrating certain components of the example door opener of FIG. 4 .

[0020] 9 provides a perspective view of an exemplary push rod according to an exemplary embodiment of the present invention that may be incorporated into a door opener, such as the exemplary door opener of FIG. 4 .

[0021] FIG. 10 provides an enlarged view of a portion of the example putter of FIG. 9 .

[0022] 11 provides a side elevational view of an exemplary push rod according to an exemplary embodiment of the present invention that may be incorporated into a door opener, such as the exemplary door opener of FIG. 4 .

[0023] FIG. 12 provides a perspective view of a guide vane of the exemplary door opener of FIG. 4 .

[0024] FIG13 provides a flow chart illustrating a method of operating a refrigeration appliance according to an exemplary embodiment of the present invention.

[0025] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. DETAILED DESCRIPTION

[0026] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. Each example is provided in an illustrative manner and does not limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope of the present invention. For example, a feature shown or described as part of one embodiment can be used in another embodiment, thereby producing yet another embodiment. Therefore, it is expected that the present invention covers these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0027] As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another, and these terms are not intended to indicate the position or importance of the various components. The terms "includes" and "including" are intended to be inclusive in a manner similar to the term "comprising." Similarly, the term "or" is generally intended to be inclusive (i.e., "A or B" is intended to mean "A or B or both"). In addition, herein and throughout the specification and claims, range limitations may be combined or interchanged. Such ranges are identified and include all subranges contained therein, unless the context or language indicates otherwise. For example, all ranges disclosed herein include endpoints, and the endpoints are independently combinable with each other. The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0028] Approximate language as used herein throughout the specification and claims may be applied to modify any quantitative representation that is permissible to vary without causing a change in the basic function to which it is related. Thus, values ​​modified by terms such as "substantially," "approximately," and "approximately" are not limited to the precise values ​​specified. In at least some cases, approximate language may correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component or system. For example, approximate language may refer to values ​​within a 10% margin (i.e., values ​​included within ten percent greater or less than the stated value). In this regard, for example, when used in the context of an angle or direction, such terminology is included within ten degrees greater or less than the stated angle or direction (e.g., "substantially vertical" includes forming an angle of up to ten degrees with the vertical V in any direction, such as clockwise or counterclockwise).

[0029] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Additionally, references to "an embodiment" or "one embodiment" do not necessarily refer to the same embodiment, but may be the same embodiment. Any embodiment described herein as "exemplary" or "an embodiment" is not necessarily to be construed as preferred or advantageous over other embodiments. Moreover, each example is given by way of explanation of the invention and does not constitute a limitation thereof. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the scope of the invention. For example, features shown or described as part of one embodiment can be used in another embodiment, resulting in yet another embodiment. Therefore, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0030] As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another, and these terms are not intended to indicate the location or importance of each component. Terms such as "left," "right," "front," "back," "top," or "bottom" are used with reference to the perspective of a user accessing a refrigeration appliance. For example, a user stands in front of a refrigerator to open the door and reaches into the food storage compartment to access the items therein.

[0031] As shown in Figures 1 to 3, the exemplary refrigeration appliance 100 includes an insulated housing or cabinet 120 defining a food storage compartment 122. A door 124 is configured to selectively seal the food storage compartment 122 when in a closed position (Figure 1) and provide access to the food storage compartment 122 when in an open position (Figure 2). The door 124 is rotatably mounted to the cabinet 120, such as by one or more hinges 126 (Figure 2), for rotation between an open position and a closed position.

[0032] The refrigeration appliance 100 defines a vertical direction V, a lateral direction L, and a transverse direction T ( FIG. 3 ), each of which is perpendicular to one another. As can be seen in FIG. 1 to FIG. 3 , the housing or casing 120 extends between a top 101 and a bottom 102 along the vertical direction V, extends between a left side 104 and a right side 106 along the lateral direction L, and extends between a front portion 108 ( FIG. 3 ) and a rear portion 110 ( FIG. 3 ) along the transverse direction T. As can be seen in FIG. 2 and FIG. 3 , a food storage chamber 122 extends between a front portion 134 and a rear portion 132 along the transverse direction T. The front portion 134 of the food storage chamber 122 defines an opening 136 for receiving food. The food storage chamber 122 is a refrigerated compartment 122 for receiving food for storage. As used herein, a chamber may be "cooled" because the chamber can operate at a temperature below room temperature (e.g., less than approximately 75 degrees Fahrenheit (75°F)). Those skilled in the art will recognize that the food storage chamber 122 can be cooled by a sealed refrigeration system so that the food storage chamber 122 can operate at or near the temperatures described herein by providing cool air from the sealed system. Those skilled in the art understand the structure and function of such a sealed system and, for the sake of brevity and clarity, will not be described in further detail herein.

[0033] The refrigerated door 124 is rotatably mounted (e.g., hinged) to the edge of the cabinet 120 for selectively accessing the fresh food compartment 122 within the cabinet 120. The refrigerated door 124 can be mounted to the cabinet 120 at or near the front 134 of the food storage compartment 122 so that the door 124 moves (e.g., rotates via hinge 126) between a closed position ( FIG. 1 ) and an open position ( FIG. 2 ). In the closed position of FIG. 1 , the door 1 seals the food storage compartment 122. In addition, one or more seals and other sealing devices may be provided to facilitate sealing between the door 124 and the cabinet 120, which are not shown but will be understood by those of ordinary skill in the art. In the open position of FIG. 2 , the door 124 allows access to the fresh food compartment 122.

[0034] 2 and 3 , various storage components may be installed within the food storage compartment 122 to facilitate storage of food therein, as will be appreciated by those skilled in the art. Specifically, the storage components include a box 116, a drawer 117, and a shelf 118 installed within the fresh food compartment 122. The box 116, the drawer 117, and the shelf 118 are used to receive food (e.g., beverages or solid foods) and may help organize such food.

[0035] As described, the housing 120 defines a single refrigeration compartment for receiving food for storage. In this example, the single refrigeration compartment 122 is a fresh food compartment 122. In some embodiments, the refrigeration compartment may be a freezer compartment, or the refrigeration appliance 100 may include one or more additional refrigeration compartments for receiving various food items and storing them at various temperatures as desired. For example, the refrigeration appliance 100 may include one or more refrigeration compartments for deep freezing (e.g., at approximately 0°F or lower) storage, or for cooling (e.g., produce or wine) at relatively warmer temperatures, such as approximately 60°F or higher (but still below room temperature, as described above), as well as any suitable temperature in between. In various exemplary embodiments, the refrigeration compartment 122 may be selectively operable at any number of various temperatures or temperature ranges, as desired or required for each application, or the refrigeration appliance 100 may include one or more additional compartments that are selectively operable at any suitable food storage temperature.

[0036] The refrigeration appliance 100 typically includes a controller 150 that is operably coupled or in communication with components of the refrigeration system of the refrigeration appliance 100, which is configured to cool the refrigeration compartment 122. As will be appreciated, such components may include a compressor, an evaporator fan, and a condenser fan. The controller 150 may selectively operate such components to cool the refrigeration compartment 122. The controller 150 may also communicate with a thermostat (e.g., a thermocouple or thermistor) disposed in the refrigeration compartment 122. The controller 150 may receive a signal corresponding to the temperature of the refrigeration compartment 122 from the thermostat. The controller 150 may also include an internal timer for calculating elapsed time periods.

[0037] The controller 150 may include a memory and one or more microprocessors, CPUs, etc., such as general-purpose or special-purpose microprocessors, which are used to execute programmed instructions or microcontrol codes associated with the operation of the refrigeration appliance 100. The memory may represent a random access memory such as DRAM or a read-only memory such as ROM or FLASH. In some embodiments, the processor executes permanent programmed instructions stored in the memory. For certain embodiments, the instructions include a software package configured to operate the appliance 100 or perform a door opener operation (for example, see the exemplary method 600 described below in FIG13). The memory may be a component separate from the processor or may be included on board within the processor. Alternatively, the controller 150 may be constructed to perform control functions without using a microprocessor (for example, using a combination of independent analog or digital logic circuits; such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, etc.), rather than relying on software.

[0038] The controller 150 can be disposed at various locations throughout the refrigeration appliance 100. Input / output ("I / O") signals can be routed between the controller 150 and the various operating components of the refrigeration appliance 100. One or more components of the refrigeration appliance 100 can communicate (e.g., electrically) with the controller 150 via one or more conductive signal lines or a shared communication bus. Additionally or alternatively, one or more components of the refrigeration appliance 100 can be in operable communication (e.g., wirelessly) with the controller 150 via one or more wireless signal bands.

[0039] In certain embodiments, a door switch 152 (e.g., a reed switch, a push-rod switch, etc.) is configured to be in operable communication with the controller 150 and selectively engage the door 124 to detect whether or when the door 124 is in an open position or otherwise moved from a closed position. Such a switch is generally understood and, for example, can simultaneously control the activation of a light that illuminates the refrigeration compartment 122. Opening the refrigeration door 124 can thereby activate the light and indicate that the door is no longer in a closed position.

[0040] The exemplary refrigeration appliance 100 illustrated is often referred to as a single-door or dedicated refrigerator, sometimes also referred to as a column refrigerator. However, it is recognized that the benefits of the present invention are applicable to other types and styles of refrigerators, such as bottom-mounted refrigerators, top-mounted refrigerators, side-by-side refrigerators, or freezers. Therefore, the description set forth herein is for illustrative purposes only and is not intended to limit any particular refrigeration compartment configuration. Furthermore, the door opener described herein can be used with other types of appliances, such as microwave ovens, washer / dryers, or any other environment where the disclosed features may be desirable.

[0041] As can be seen in Figures 2 and 3, the refrigeration appliance 100 may include a door opener 200. The door opener 200 may be disposed within or attached to the housing 120. For example, the door opener 200 may be disposed outside and adjacent to the chamber 122. In some exemplary embodiments, the door opener 200 may contact or be embedded within the insulating material (e.g., foam) surrounding the chamber 122. In other exemplary embodiments, the door opener 200 may be attached to the exterior of the housing 120 above the top of the housing 120. For example, the door opener 200 may be disposed near the front 108 of the housing 120 and the opening 136 of the food storage compartment 122. In the illustrated exemplary embodiment, the door opener 200 is disposed near the top 101 of the housing 120 along the vertical direction V and approximately centered along the horizontal direction L. That is, as best seen in Figure 2, the exemplary door opener 200 is disposed at or around the lateral midpoint of the opening 136 of the housing 120 or the food storage compartment 122. In other embodiments, the door opener 200 can be set in other positions, such as near the bottom 102 along the vertical direction V. In some embodiments, centering the door opener 200 along the lateral direction L can advantageously provide flexibility in installing the door body 124. For example, the refrigeration appliance 100 illustrated includes a door body 124 installed on the right side 106. In other embodiments, the door body 124 (e.g., hinge 126) can be installed to the housing 120 at or near the left side 104. In an embodiment in which the door opener 200 is centered along the lateral direction L, when the door body 124 is installed to the left side 104 or the right side 106, the door opener 200 will apply substantially the same opening force to the door body 124. For example, the moment arm or leverage applied to the door body 124 when the door body 124 rotates about the hinge 126 will be substantially the same.

[0042] Typically, the door opener 200 includes a housing 202 and a push rod (e.g., a screw) 206. As shown, the housing 202 is coupled to the housing 120 (e.g., via mechanical fasteners). Thus, the housing 202 can be fixedly mounted to the housing 120 because, during normal and expected operation of the refrigeration appliance 100 (including its door opener 200), the housing 202 cannot move relative to the housing 120. The push rod 206 can move relative to the housing 202 of the door opener 200 and relative to the housing 120 of the refrigeration appliance 100. Thus, the push rod 206 can selectively move toward (and subsequently away from) the door 124 to open the door. For example, the push rod 206 can move axially (e.g., parallel to the transverse direction T) between a retracted position ( FIG. 6 , dashed line) and an extended (e.g., fully extended) position ( FIG. 6 , dotted line) to force the door 124 forward so that the door 124 can pivot open. As shown, in the retracted position, the push rod 206 can remain flush with or behind the housing 202 (e.g., at the tip 212), while the extended position can maintain the push rod 206 outside the front of the housing 202 (e.g., at the tip 212). Between the retracted and extended positions, a zero or partial extension position ( FIG. 3 ) can be established to contact the inner surface of the door body 124 in the closed position (e.g., as will be described below).

[0043] In some embodiments, the push rod 206 includes a front portion or stem portion 210 and a threaded middle portion 208. The push rod 206 may also include a rear portion 250 having a guide element defined thereon. For example, the guide element can limit rotation of the push rod 206 about the transverse direction T, whereby the push rod 206 can generally translate along the transverse direction T (described further below) with little or no twisting or rotation about the transverse direction T. In various embodiments, the guide element includes one or more slots 252 (e.g., Figures 6 and 9) or one or more fins 256 (e.g., Figure 11). When configured, the slots 252 can receive tabs 254 (Figure 6) of the housing 202 therein to limit rotation of the push rod 206 about the transverse direction T. When configured, the fins 256 can be received within corresponding slots defined in the housing 202 to limit rotation of the push rod 206 about the transverse direction T.

[0044] In some embodiments, the push rod 206 includes a tip 212 that engages the inner surface 125 of the door 124 (see, for example, FIG. 6 ). The push rod 206 (e.g., its stem portion 210) can extend through the housing 202 toward the door 124 of the refrigeration appliance 100 (e.g., as can be seen in FIG. 3 ). As shown in FIG. 3 , the door opener 200 is in a zero position. FIG. 3 illustrates the zero position of the door opener 200, and in particular, the push rod 206, relative to the cabinet 120 of the refrigeration appliance 100. Furthermore, the door opener 200 can be moved from the zero position (e.g., forward in the transverse direction T), as shown in dashed lines in FIG. 6 . In this extended position, the push rod 206 is fully extended from the housing 202 to force the door 124 away from the cabinet 120 (e.g., away from the closed position of the door 124 illustrated in FIG. 3 and toward the open position of the door 124 illustrated in FIG. 2 ).

[0045] In some embodiments, one or more sensors 302 or 304 are configured to detect relative movement between the push rod 206 and the housing 202. Specifically, such sensors 302 or 304 can be in operative communication with the motor 204 or the controller 150. Thus, the sensors 302 or 304 can be configured to transmit a signal to the controller 150 or the motor 204 in response to the sensor 302 or 304 detecting movement of the push rod 206 (e.g., when the sensor detects the movement). Alternatively, the controller 150 or the motor 204 can be configured to receive a signal from the sensor 302 or 304, to activate in response to the signal from the sensor 302 or 304, and to move the push rod 206 along the lateral direction T toward the front 108 of the housing 120 or the front of the housing 202.

[0046] In some embodiments, the sensor includes a position sensor 302. For example, the position sensor 302 may be disposed on or in communication with the push rod 206 (e.g., at its rear end). Generally, the position sensor 302 may include any suitable sensor configured to detect the relative position of the push rod 206 between a retracted position and an extended position (e.g., including such positions). As an example, the position sensor 302 may include or be provided as a time-of-flight (TOF) sensor configured to calculate the distance between a portion of the push rod 206 and a fixed element (e.g., a predetermined portion of the housing 202). As an additional or alternative example, the position sensor 302 may include or be provided as a linear encoder or potentiometer configured to sense or respond to a change in the length of the linear sensor 302, wherein the length of the linear sensor 302 is defined along the transverse direction T between the housing 202 and the push rod 206.

[0047] In additional or alternative embodiments, the sensor includes a rod load sensor 304 configured to detect (e.g., directly or indirectly) a relative load or pressure applied to the push rod 206. As an example, the rod load sensor 306 can be provided as a Hall effect sensor at a first element (e.g., spring 232) with a mating magnet 306A fixed relative to a separate second element (e.g., push rod 206).

[0048] The push rod 206 can be biased forward (e.g., toward the front portion 108) along the transverse direction T by a protection spring 232. For example, the protection spring 232 can provide resilience when the door 124 is closed and the door opener 200 is in the extended position. For example, when the door 124 is closed and the door opener 200 is in the extended position, the protection spring 232 can allow the push rod 206 and the sliding fork 240 to deflect rearward (e.g., toward the rear portion 110) while the spring 232 absorbs force from the door 124.

[0049] Typically, the door opener 200 includes a motor 204 that is mechanically connected to a push rod 206 to guide or control the movement of the push rod 206. For example, the motor 204 can be operative with the controller (e.g., electrically or wirelessly) and actuate the push rod 206 based on one or more signals received from or sent to the controller 150. In an optional embodiment, the door opener 200 is self-reversing or automatically reversing. For example, the push rod 206 can reciprocate generally along the transverse direction T (e.g., move forward and backward between (and including) a zero position and an extended position). In at least some embodiments, this reciprocating motion can be driven by a motor 214. For example, the motor 214 can rotate the drive gear 216, and this rotation can be transferred to the push rod 206 in a manner that causes the push rod 206 to translate linearly (e.g., translate back and forth between (and including) a zero position and an extended position), as will be described in more detail below. This reciprocating motion can include, for example, movement of the push rod 206 in a first direction (e.g., forward, such as toward the front portion 108) along the transverse direction T from the zero position to the extended position, and then movement in a second direction (e.g., rearward, such as toward the rear portion 110) along the transverse direction T from the extended position to the zero position that is substantially opposite to the first direction (e.g., substantially 180° away from the first direction). For example, in some embodiments, the motor 214 can rotate the drive gear 216 in a single direction while the push rod 206 reciprocates substantially along the transverse direction T. As another example, in at least some embodiments, the motor 214 can continuously rotate the drive gear 216 while the push rod 206 reciprocates substantially along the transverse direction T. Further, in some embodiments, the drive gear 216 can rotate continuously and in a single direction (e.g., clockwise or counterclockwise). This continuous rotation of the drive gear 216 by the motor 214 can be variable and, thus, not rotate at a single speed (e.g., the rotation can be accelerated or decelerated). However, unidirectional rotation of the drive gear 216 (which may be transmitted to the push rod 206 via one or more intermediate elements (e.g., gears and guide vanes, as described in more detail below)) can cause the push rod 206 to move back and forth (e.g., in a first direction and an opposite second direction, as described above). Thus, for example, the push rod 206 can be self-reversing, at least because the push rod 206 moves in two opposite directions without the motor 214 stopping or the motor 214 changing the direction of rotation of the motor 214 or the drive gear 216.

[0050] As described above, the push rod 206 can linearly translate (e.g., reciprocate) along an axial direction. For example, as can be seen in Figures 4-6 , the door opener 200 can include multiple gears to transmit rotation from the motor 214 to the push rod 206. As a result, the push rod 206 will linearly translate due to the interaction between the guide vanes 262 and the threads of the push rod 206. In particular, Figure 5 illustrates an exemplary plurality of gears, with several adjacent components (e.g., a housing or gearbox) omitted to more clearly illustrate the exemplary gears. In some embodiments, the plurality of gears can include a reduction gear 218 that engages with the drive gear 216. For example, the reduction gear 218 can directly engage with the drive gear 216, such that the external teeth 220 of the drive gear 216 abut and directly contact the first set of external teeth 222 of the reduction gear 218, thereby causing rotation of the drive gear 216 to cause rotation of the reduction gear 218. For example, rotation of the drive gear 216 caused by the motor 214 is directly transmitted from the drive gear 216 to the reduction gear 218. As best seen in Figure 5, the reduction gear 218 can also include a second set of external teeth 224, and the second set of external teeth 224 can engage with the external teeth 228 of the gear 226 (for example, directly engage in the same manner as described above with respect to the reduction gear 218 and the drive gear 216), whereby rotation of the reduction gear 218 causes the gear 226 to rotate via the engagement of the second external teeth 224 of the reduction gear 218 with the external teeth 228 of the gear 226.

[0051] Still referring to Figures 4 to 6, the door opener 200 may also include a sliding fork 240. The sliding fork 240 may be oriented generally along the transverse direction T. For example, the longest dimension of the sliding fork 240 may be generally parallel to the transverse direction T. The sliding fork 240 may define an inner cavity 242 that extends completely through the sliding fork 240 from front to back. The push rod 206 or a portion thereof may extend through the sliding fork 240, such as through the inner cavity 242 of the sliding fork 240. The sliding fork 240 may also include external teeth 244 along at least a portion thereof, and the external teeth 244 of the sliding fork 240 may engage with the internal teeth 230 of the gear 226 (e.g., directly engage—wherein "direct engage" is used as described above).

[0052] Referring now specifically to Figures 6 and 7, the sliding fork 240 can be formed of a multi-part construction (e.g., a two-part construction including a front portion 258 and a rear portion 260). In certain embodiments, a guide vane 262 can be captured within the sliding fork 240, such as between the front portion 258 of the sliding fork 240 and the rear portion 260 of the sliding fork 240. As can be seen, for example, in Figures 7 and 8, the guide vane 262 can be captured within a recess 264 defined within the sliding fork 240. Additionally, it should be noted that Figure 8 presents a partial cross-sectional view of a portion of the door opener 200. In particular, the cross-section in Figure 8 is taken through the threaded portion 208 of the push rod 206 (e.g., such that the guide vane 262 is partially obscured by the crests 268 of the threads of the push rod 206 in Figure 8 (see also Figure 10)). Specific features of the exemplary guide vane 262 will be described in more detail below with reference to Figures 10 and 12.

[0053] As can be seen in Figures 6 to 8, the guide vane 262 engages with the threads on the threaded portion 210 of the push rod 206. For example, as the slide fork 240 rotates about the push rod 206, the guide vane 262 can move within the threads. As described above, the guide vane 262 is captured by the slide fork 240 so that as the slide fork 240 rotates about the push rod 206, the guide vane 262 rotates about the push rod 206. The guide vane 262 is also free to pivot within the recess 264 of the slide fork 240 so that the angle of the guide vane 262 relative to the push rod 206 changes in response to changes in the pitch of the push rod 206. This change in pitch will be described further below.

[0054] FIG10 provides an enlarged view of the threaded portion 208 of the push rod 206. As shown in FIG10 , the push rod 206 defines a longitudinal axis 300. Thus, the push rod 206 also defines an axial direction along or parallel to the longitudinal axis 300, as well as a radial direction perpendicular to the axial direction and a circumferential direction extending about the axial direction. As shown in FIG10 , the thread 208 circumscribes the push rod 206 and defines a series of roots 266 and crests 268. The thread of the push rod 206 can circumscribe the push rod 206 along a circumferential direction about the longitudinal axis 300 of the push rod 206 and can be oriented at an oblique angle to the radial direction. The thread of the push rod 206 can be a helical thread. For example, the thread can be a double helical thread, defining a first helical path along which the guide vanes 262 travel to propel the push rod 206 forward, and a second helical path continuously connected end-to-end to the first helical path, wherein the guide vanes 262 travel along the second helical path to propel the push rod 206 backward. The helical thread of the push rod 206 can also define a centerline 320 (e.g., substantially equidistantly spaced between each adjacent crest 268 of the helical thread). As shown in FIG. 10 , the centerline 320 of the helical thread can define a pitch angle 322 relative to the longitudinal axis 300 of the push rod 206. For example, FIG. 10 annotates a forward pitch measured from the longitudinal axis 300 of the push rod 206 toward the front portion 210 of the push rod 206, such as can be defined by the first helical path of the double helical thread, as described above. Although not specifically annotated in FIG. 10 , it should be understood that the second helical path of the double helical thread defines a rearward pitch that is substantially opposite (e.g., approximately 180° thereto) to the annotated forward pitch. As can be seen, for example, in FIG. 10 , the helical thread of the push rod can define a variable pitch 322, such as a pitch angle 322 that can vary across the threaded portion 208 of the push rod 206. For example, the pitch angle 322 may be greater (eg, steeper) about the center of the threaded portion 208 (along the transverse direction T) and smaller (eg, shallower) at each transverse (eg, front and rear) end of the helical thread across the threaded portion 208 .

[0055] As described above, when the motor 214 is activated (e.g., when the slide fork 240 rotates circumferentially), the slide fork 240 rotates about the push rod 206. Also as described above, the guide vane 262 is captured within the slide fork 240 (e.g., such that the guide vane 262 is prevented from linearly translating radially toward or away from the longitudinal axis 300 of the push rod 206), and when the motor 214 is activated, the guide vane 262 also rotates circumferentially about the push rod 206 along with the slide fork 240. The guide vane 262 can also pivot within the slide fork 240 (e.g., within the recess 264 thereof), such as by generally pivoting radially. Thus, while the slide fork 240 rotates about the push rod 206, the guide vane 262 can contact and engage the helical threads of the push rod 206 (e.g., at least the crests 268 thereof), and due to this engagement, the guide vane 262 can propel the push rod 206 to reciprocate along the lateral direction T (e.g., forward and backward). Further, the rate of travel of the push rod 206 can be proportional to the pitch 322 of the thread. For example, the push rod 206 can travel faster when the guide vane 262 traverses a steeper pitch middle portion of the helical thread, and the push rod can travel slower when the guide vane travels through a shallower pitch end portion of the helical thread. Thus, the door opener 200 can have a short dwell time at one or both of the zero position and the fully extended position. For example, staying in the fully extended position can provide the user with an opportunity to grab the door body 124 and pull the door body 124 the remaining way (e.g., from a partially open position to a fully open position). Such a dwell time or multiple dwell times at one or both extremes of the lateral range of movement of the push rod 206 can also or alternatively be provided by changing (e.g., slowing to a non-zero value or stopping) the speed of the motor 214.

[0056] FIG12 illustrates an exemplary guide vane 262 in perspective view. As can be seen in FIG12 , guide vane 262 can include an outer flange 270, where "outer" refers to being further away from push rod 206, such as radially away from its longitudinal axis 300. Outer flange 270 can be captured within a larger portion of recess 264 in slide yoke 240 (see, for example, FIG8 ) and can directly abut a neck 272 of guide vane 262, where neck 272 is narrower (e.g., defining a smaller outer diameter than flange 270). Neck 272 can be captured within a narrower portion of recess 264 in slide yoke 240 than flange 270, thereby helping to limit linear movement of guide vane 262 in a radial direction (e.g., toward or away from push rod 206). As can be seen in FIG12 , the cross-sectional shape of flange 270 and neck 272 can be round (e.g., circular), such as in a cross-section taken generally perpendicular to the radial direction. Additionally, the guide vane 262 may further include a base portion 274 that directly abuts the neck 272 at an end thereof opposite the end of the neck 272 abutting the flange 270, and the base portion 274 may further define a rounded (e.g., circular) cross-sectional shape. Further, corresponding portions of the recess 264 in the sliding fork 240 may each define a complementary circular shape to allow the guide vane 262 to pivot within the recess 264 (e.g., generally radially), as described above, thereby promoting consistent engagement and contact of the guide vane 262 (particularly its tapered vane portion 276) with the helical thread of the push rod 206, particularly in embodiments where the helical thread defines a variable pitch. When the guide vane 262 is assembled within the sliding fork 240 as described above and the push rod 206 extends through the inner cavity 242 of the sliding fork 240, the tapered blade portion 276 of the guide vane 262 (which is partially obstructed by the threads in FIG8 , as discussed above with respect to FIG8 ) can extend from the base 274 of the guide vane 262, such as toward the push rod 206 (e.g., toward its longitudinal axis 300). The tapered blade portion 276 can terminate in a concave curved surface 278. The concave curved surface 278 can be generally complementary to the root 266 of the threads of the push rod 206. When the door opener 200 is fully assembled, the concave curved surface 278 can be generally parallel to and spaced apart from the root 266 of the threads of the push rod 206 (e.g., as can be seen in FIG7 ).

[0057] The guide vanes 262 may be constructed of any suitable low-friction material. For example, the guide vanes 262 may include a low-friction polymer (eg, plastic) material, such as acetal plastic or nylon.

[0058] Turning to FIG. 13 , now that the configuration of the refrigeration appliance 100 and door opener 200, as well as the configuration of the controller 150, according to an exemplary embodiment have been presented, an exemplary method (e.g., 600) for operating one or more washing machine devices will be described. Although the following discussion relates to an exemplary method for operating a refrigeration appliance (e.g., appliance 100) or a door opener (e.g., door opener 200), those skilled in the art will understand that the aforementioned configuration is merely exemplary, and that method 600 does not require such configuration, unless otherwise specified. In other words, appliance 100 and door opener 200 are merely exemplary, and any suitable appliance (e.g., having a cabinet and a door) or door opener (e.g., configured to at least partially open a door) may be provided. Thus, exemplary method 600 may be applied to the operation of various other refrigeration appliances or appliances in general. In an exemplary embodiment, the various method steps disclosed herein may be performed (e.g., in whole or in part) by controller 150.

[0059] 6 depicts the steps performed in a specific order for purposes of illustration and discussion. Using the disclosure provided herein, one of ordinary skill in the art will appreciate that the steps of method 600 may be modified, adapted, rearranged, omitted, interchanged, or expanded in various ways without departing from the scope of the present invention.

[0060] Advantageously, the method according to the present invention can ensure consistent opening results of the door body (e.g., over time). Additionally or alternatively, this method can advantageously maintain alignment between the door opener and the door body (e.g., automatically or without direct user intervention).

[0061] At 610, method 600 includes detecting movement of the door from a closed position. As described above, the closed position typically provides a sealed engagement with the housing of the refrigeration appliance to close the door (e.g., its seal) of the refrigeration compartment. Thus, movement of the door away from the closed position (e.g., a predetermined opening threshold) can be detected by one or more corresponding sensors. By way of example, and as will be appreciated, a door switch can detect a point at which the door is no longer engaged with the door switch or has otherwise moved beyond a predetermined opening threshold (i.e., from the predetermined opening threshold forward). As an additional or alternative example, a rod load sensor can detect when the door is pulled outward and disengaged from the push rod (e.g., based on detected relative movement between a magnet and the rod load sensor). In some embodiments, at 610, the push rod is understood to be engaged with (e.g., in contact with) the door. Thus, the push rod can be in a zero position or an extended position (e.g., if the user has not yet opened the door further from the extended position).

[0062] At 612, method 600 includes guiding the push rod to a retracted position. In particular, the push rod can be pulled backward from, for example, a zero position or an extended position or some other intermediate position. For example, a motor can drive the push rod so that the push rod (e.g., its tip) is withdrawn into or within the housing or casing. As described above, the push rod can be driven by a unidirectional motor so that after reaching the extended position, the push rod moves backward and can thereby be moved all the way to the retracted position. Of course, other embodiments or door openers can move the push rod backward via another suitable mechanism. In some embodiments, 612 is after 610. Thus, 610 can be before 612. In some embodiments, 612 is in response to 610. Therefore, 612 can be a direct result of the detection of 610.

[0063] At 614, method 600 includes detecting that the door is in the closed position (e.g., after 612). Thus, it can be determined that the door is fully closed again after 612 and while the push rod remains in the retracted position. Again, as described above, the closed position typically provides a sealing engagement with the cabinet of the refrigeration appliance to close the door (e.g., its seal) of the refrigeration compartment. Thus, movement of the door back to the closed position (e.g., from a predetermined closed threshold, which may be the same as or alternatively different from a predetermined open threshold) can be detected by one or more corresponding sensors. By way of example, and as will be appreciated, a door switch can detect a point at which the door is disengaged from the door switch or otherwise moved from a predetermined closed threshold. As an additional or alternative example, a rod load sensor can detect when the door has returned to engagement with the cabinet (e.g., based on detected relative movement between a magnet and the rod load sensor caused by pressure from the closing door). In some embodiments, at 620, the push rod is understood to be not significantly engaged with (e.g., in contact with) the door.

[0064] At 616, method 600 includes maintaining the push rod in the retracted position (e.g., after 614). Thus, the push rod can be retracted even if the door body is in the closed position. In particular, the push rod can be maintained in the retracted state within a set interval (i.e., for the duration of the set interval). Thus, during the set interval, the push rod can be restricted from moving forward (e.g., to a zero position or an extended position). Typically, the set interval is a function of a predetermined amount or time. In some embodiments, 616 is responsive to 614. The set interval itself can be started or triggered by 614, thereby, the set interval can be counted down from it.

[0065] At 618, method 600 includes determining a first baseline position setting for the push rod (e.g., at a rod load sensor). For example, one or more signals from one or more sensors of the door opener may be received. Such signals may generally indicate or correspond to a reading of a sensor (e.g., a position sensor or a rod load sensor), thereby corresponding to a detected value of the position of the push rod. As will be appreciated, the received signal may be an isolated signal or multiple signals (e.g., averaged to reduce noise or erroneous readings).

[0066] Typically, the first baseline position setting can be determined when the push rod is in the retracted position. Specifically, 618 can occur in series with or simultaneously with at least a portion of 616. Thus, 618 can be within a set interval. Additionally or alternatively, 618 can be responsive to 614 or 616.

[0067] At 620, method 600 includes directing the push rod forward from the retracted position. For example, the motor of the door opener can be directed to advance the push rod toward the extended position, but this is not required. The extension speed or the speed at which the push rod is directed forward can be predetermined and, optionally, relatively low or slow compared to the extension speed used to open the door body. Typically, 620 is after at least 614. In some embodiments, 620 is further after 616 or 618. For example, 620 can be responsive to the expiration of a set interval. Thus, 620 can include determining the expiration of the set interval and causing the push rod to move forward in response to determining the expiration of the set interval.

[0068] At 622, method 600 includes monitoring a sensor output at a rod load sensor while directing the putter forward. Thus, 622 can occur in series with or simultaneously with at least a portion of 620. Specifically, as the putter moves forward, a load signal can be received from the rod load sensor (e.g., according to a set pattern or rate). Furthermore, 622 can include evaluating the received load signal to determine what the load or relative position of the putter is at a given moment (e.g., compared to a first baseline position setting).

[0069] At 624, method 600 includes detecting contact with the door body (i.e., contact between the push rod and the door body). This detection can be based on the monitored rod load sensor signal (i.e., load signal) of 622. Thus, 624 can occur while monitoring the sensor output (e.g., at 622). This contact can be detected, for example, based on a change in the sensor output (e.g., a change in the continuous load signal value exceeding a predetermined change threshold). In some such embodiments, 624 thus includes detecting a change in the sensor output during the monitoring period. Furthermore, it can be determined that the detected change is above the predetermined change threshold.

[0070] At 626, method 600 includes stopping the push rod at the partially extended position (e.g., based on or in response to 624). For example, once contact with the door is determined, further forward movement of the push rod can be stopped. The push rod can remain in the same partially extended position in which it was stopped. Thus, the push rod can maintain contact with the door.

[0071] At 628, method 600 includes determining a second baseline position setting for the push rod (e.g., at the rod load sensor). For example, one or more signals from one or more sensors of the door opener may be received. Such signals may generally indicate or correspond to a reading of a sensor (e.g., a position sensor or a rod load sensor), thereby corresponding to a detected value of the position of the push rod. As will be appreciated, the received signal may be an isolated signal or multiple signals (e.g., averaged to reduce noise or erroneous readings).

[0072] The second baseline position setting can be determined at the rod load sensor in the partially extended position of 626. In other words, 628 can be determined from the signal received when the push rod is maintained in the partially extended position of 626. In some embodiments, the second position setting is adopted as a zero (i.e., new zero) position. Thus, any previously saved zero position can be changed to the new zero position. Thus, any subsequent steps that use the zero position or determine from the zero position can use the new zero position (e.g., until another subsequent zero position is determined). In particular, the starting (e.g., zero) position of the push rod in contact with the door body can be determined regardless of the age or wear of the appliance and without direct user intervention (e.g., automatically).

[0073] At 630, method 600 includes monitoring a sensor output at the rod load sensor while in the partially extended position. For example, 630 may occur after 628 (e.g., before the putter moves further from the new zero position). Specifically, while the putter remains in the partially extended or new zero position, a load signal may be received from the rod load sensor (e.g., according to a set pattern or rate). Furthermore, 630 may include evaluating the received load signal to determine what the load or relative position of the putter is at a given moment (e.g., compared to a second baseline position setting).

[0074] At 632, method 600 includes detecting movement of the door body from the partially extended position. This detection can be based on the monitored rod load sensor signal (i.e., load signal) of 630. Thus, 632 can occur while monitoring the sensor output (e.g., at 630). Such movement can be detected as forward or rearward movement, for example, based on a change in the sensor output (e.g., a change in the continuous load signal value exceeding a predetermined change threshold). In some such embodiments, 632 thus includes detecting a change in the sensor output during the monitoring of 630. Furthermore, it can be determined that the detected change exceeds a predetermined change threshold (e.g., different from or the same as the predetermined change threshold of 624).

[0075] The detected change can be determined to be indicative of forward movement, such as that which may occur in response to a user opening the door from a closed position. For example, a user pivoting the door open can cause a decrease in the load on the rod load sensor. Thus, 632 can include detecting the opening of the door from a closed position. Alternatively, the detected change can be determined to be indicative of rearward movement, such as that which may occur in response to a user pushing on the door. For example, a user pushing inward / rearward on a door in a closed position can cause the push rod to move rearward from a partially extended (e.g., new zero) position, thereby causing an increase in the load on the rod load sensor. Thus, 632 can include detecting (e.g., rearward) movement of the push rod.

[0076] At 634, method 600 includes directing movement of the push rod based on the detected door movement. For example, 634 may include directing forward or rearward movement of the push rod (e.g., from a partially extended position) based on whether door opening movement or push movement is detected.

[0077] As an example, in response to detecting that the door is opened from the closed position, 634 may include guiding the push rod backward (e.g., and back to the retracted position). For example, a motor may drive the push rod so that the push rod (e.g., its tip) is withdrawn into or within the housing or box. As described above, the push rod may be driven by a unidirectional motor so that after reaching the extended position, the push rod moves backward and can thereby move all the way to the retracted position. Of course, other embodiments or door openers may move the push rod backward via another suitable mechanism.

[0078] As an additional or optional example, in response to detecting (e.g., backward) movement of the push rod, 634 may include guiding the push rod forward beyond the partially extended position. For example, the motor may drive the push rod so that the push rod (e.g., its tip) is driven forward from the housing or casing to a length greater than the partially extended position. The push rod can, in turn, act against the inner surface of the door body and move the door body forward from the closed position. Thus, the push rod moving forward can overcome the inertia of the door body and push the door body toward the open position. Optionally, the hinge of the door body can be constructed so that once the door body begins to swing toward the open position (e.g., in response to the push rod of the door opener 200 being pushed outward / forward laterally against the inner surface), the momentum of the door body will bring the door body completely to the open position. Of course, other embodiments or door openers can move the push rod forward (e.g., and open the door) via another suitable mechanism.

[0079] This written description uses examples to disclose the invention (including the best mode) and also to enable those skilled in the art to practice the invention (including making and using any device or system and performing any method included). The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. If such other examples include structural elements that do not differ from the literal language of the claims, or if such other examples include equivalent structural elements that do not differ substantially from the literal language of the claims, such other examples are intended to fall within the scope of the claims.

Claims

1. A refrigeration appliance, characterized in that: The refrigeration appliance defines a vertical direction, a lateral direction, and a transverse direction, wherein the vertical direction, the lateral direction, and the transverse direction are perpendicular to each other, and the refrigeration appliance includes: a housing defining a food storage chamber extending along the transverse direction between a front portion and a rear portion, the front portion of the food storage chamber defining an opening for receiving food; a door body disposed at the front portion of the food storage chamber and movable between a closed position and an open position to selectively seal the food storage chamber in the closed position and provide access to the food storage chamber in the open position; a door opener attached to the housing, the door opener comprising a housing fixedly mounted to the housing, a push rod extending through the housing toward the door and movable relative to the housing to push the door toward the open position, and a rod load sensor attached to the housing to detect a mechanical load on the push rod; and a controller in operable communication with the door opener and configured to direct door opener operation, the door opener operation comprising: guiding the push rod to a retracted position; detecting that the door body is in the closed position after guiding the push rod to the retracted position; guiding the push rod forward from the retracted position after detecting that the door body is in the closed position; monitoring a sensor output at the rod load sensor while directing the push rod forward; detecting contact with the door body while monitoring the sensor output; and The push rod is stopped at the partially extended position in response to detecting contact.

2. The refrigeration appliance according to claim 1, characterized in that: The door opener operation also includes: Movement of the door body from the closed position is detected before guiding the push rod to the retracted position.

3. The refrigeration appliance according to claim 1, characterized in that: The door opener operation also includes: maintaining the push rod in the retracted position for a set interval in response to detecting that the door body is in the closed position; and A first baseline position setting of the pushrod is determined at the rod load sensor in the retracted position.

4. The refrigeration appliance according to claim 1, characterized in that: Detecting contact with the door includes detecting a change in the sensor output during a monitoring period.

5. The refrigeration appliance according to claim 4, characterized in that: The door opener operation also includes: A second baseline position setting of the push rod is determined at the rod load sensor in the partially extended position.

6. The refrigeration appliance according to claim 1, characterized in that: The door opener operation also includes: A sensor output at the rod load sensor is monitored while in the partially extended position.

7. The refrigeration appliance according to claim 6, characterized in that: The door opener operation also includes: Movement of the door from the partially extended position of the push rod is detected.

8. The refrigeration appliance according to claim 7, characterized in that: The door opener operation also includes: The movement of the push rod is guided based on the detected movement of the door body.

9. The refrigeration appliance according to claim 7, characterized in that: Detecting door movement includes detecting a change in the sensor output at the rod load sensor during monitoring of the sensor output at the rod load sensor when in the partially extended position, and Wherein, the door opener operation further includes: The push rod is directed forward beyond the partially extended position in response to detecting movement of the push rod.

10. The refrigeration appliance according to claim 7, characterized in that: Detecting door movement includes detecting opening of the door from the closed position, and Wherein, the door opener operation further includes: In response to detecting that the door body is opened from the closed position, the push rod is guided rearward and returned to the retracted position.

11. A method for operating a door opener of a refrigeration appliance comprising a cabinet and a door, characterized in that: The method comprises: guiding a push rod of the door opener to a retracted position; detecting that the door body is in the closed position after guiding the push rod to the retracted position; guiding the push rod forward from the retracted position after detecting that the door body is in the closed position; monitoring a sensor output at a rod load sensor of the door opener while directing the push rod forward; detecting contact with the door body while monitoring the sensor output; and The push rod is stopped at the partially extended position in response to detecting contact.

12. The method according to claim 11, characterized in that Also includes: Movement of the door body from the closed position is detected before guiding the push rod to the retracted position.

13. The method according to claim 11, characterized in that Also includes: maintaining the push rod in the retracted position for a set interval in response to detecting that the door body is in the closed position; as well as A first baseline position setting of the pushrod is determined at the rod load sensor in the retracted position.

14. The method according to claim 11, characterized in that Detecting contact with the door includes detecting a change in the sensor output during a monitoring period.

15. The method according to claim 14, characterized in that Also includes: A second baseline position setting of the push rod is determined at the rod load sensor in the partially extended position.

16. The method according to claim 11, characterized in that Also includes: A sensor output at the rod load sensor is monitored while in the partially extended position.

17. The method according to claim 16, characterized in that Also includes: Movement of the door from the partially extended position of the push rod is detected.

18. The method according to claim 17, characterized in that Also includes: The movement of the push rod is guided based on the detected movement of the door body.

19. The method according to claim 17, wherein Detecting door movement includes detecting a change in the sensor output at the rod load sensor during monitoring of the sensor output at the rod load sensor when in the partially extended position, and The method further comprises: The push rod is directed forward beyond the partially extended position in response to detecting movement of the push rod.

20. The method according to claim 17, wherein Detecting door movement includes detecting opening of the door from the closed position, and The method further comprises: In response to detecting that the door body is opened from the closed position, the push rod is guided rearward and returned to the retracted position.

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