The present invention relates to dishwashers and more particularly to structures and methods configured to attenuate sound generated from the dishwashers during use.
One issue of interest in the field of dishwashers is to reduce the externally perceptible noise generated by the dishwasher when the dishwasher is in use. Due to the number of mechanical devices cooperating to circulate the water to clean and rinse the dishware within the dishwasher, the sources and conduits of sound are numerous and determining ways to reduce the noise may be challenging.
One or more embodiments of a dishwasher are disclosed with an improved sound attenuating property. According to an embodiment, a dishwasher configured to clean dishware is provided. The dishwasher may include a tub configured to receive and hold the dishware and a first panel of an acoustic composite membrane. The acoustic composite membrane may include a layer of an acoustic tape comprising a plurality of first fibers extending in a first direction and of second fibers extending in a second direction and configured to redirect and convert at least a portion of a sound power level generated by the dishwasher into heat such that the sound power level perceivable outside the dishwasher is reduced. The first and second direction may be perpendicular such that the first and second fibers form a grid-like pattern. Alternatively, the acoustic tape may include a non-fibrous layer and a plurality of fibers mounted thereon.
The acoustic composite membrane may further include a first foam layer configured to absorb at least a portion of the sound power level and to reduce the speed of the sound power level prior to the sound power level reaching the acoustic tape. The acoustic composite membrane may also include a second foam layer and a vinyl layer between the first and second foam layers, the vinyl layer being configured to convert at least a portion of the sound power level into heat.
According to another embodiment, the dishwasher includes at least one mechanical device for operating the dishwasher and a base for supporting the tub and providing an enclosure for the at least one mechanical device. The base comprises a toe plate assembly that includes an inner support panel and an outer support panel. In this embodiment, the first panel of the acoustic composite membrane is adjacent an inner surface of the outer support panel. The dishwasher may further include a second panel of the acoustic composite membrane that is positioned adjacent an outer surface of the inner support panel.
In another embodiment, the dishwasher includes a door assembly configured to provide access to an interior of the tub. In this embodiment, the door assembly includes an inner wall, and an outer wall, and the first panel of the acoustic composite membrane is between the inner and outer walls.
In yet another embodiment, the dishwasher comprises a base for supporting the tub. The interface of the tub and the base defines a crevice between the tub and the base. In this embodiment, the first panel of the acoustic composite membrane extends along and over the crevice. The dishwasher may further include a layer of material configured to vibrate from the sound power level and positioned between the crevice and the first panel of the acoustic composite membrane.
Referring to yet another embodiment, the dishwasher may include a door assembly configured to provide access to an interior of the tub, a frame including a base configured to support the tub, and one or more framing elements extending from the base around the tub and proximate to the door assembly. In this embodiment, the first panel of the acoustic composite panel extends between the door assembly and a framing element along a first side of the tub and a second panel of the acoustic composite membrane extends between the door assembly and a framing element along a second side of the tub.
In other embodiments, instead of or in addition to the acoustic composite membrane described above, the dishwasher may include one or more other laminated structures including a layer of the acoustic tape. For example, the dishwasher may include a laminated structure positioned and configured to attenuate a sound power level generated by the dishwasher. The laminated structure including a layer of the acoustic tape and further include a first foam layer and second and third vinyl layers. The second vinyl layer may be between the first foam layer and the third vinyl layer. The laminated structure may be positioned within a cavity of the door assembly of the dishwasher.
In yet other embodiments, the dishwasher may include one or more panels of the acoustic composite membrane and other laminated structures positioned within the dishwasher according to any combination of the previous described embodiments or methods may be used to provide such a dishwasher.
Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
The door assembly 50 may be pivotably engaged with the tub 13 about the lower end 18 thereof so as to selectively permit access to the interior of the tub 13. That is, a lower edge 26 of the door assembly 50 may be pivotably engaged (e.g., hinged) with the lower end 18 of the tub 13 such that the door assembly 50 is pivotable about the lower edge 26 thereof to cover and seal the forward access opening 16 in a closed position when the dishwasher 10 is in operation, and to provide access to the interior of the tub 13 through the forward access opening 16 when the door assembly 50 is pivoted from the closed position to an opened position. In some instances, the door assembly 50 may comprise an inner wall 60 and an outer wall 70. The door assembly 50 may include a handle member 24 disposed on an outer surface 72 of the outer wall 70 to provide the user with a grasp portion.
Embodiments are generally directed to the use of a composite acoustic membrane configured to manage sound and noise generated by the dishwasher. According to the embodiment illustrated in
The thickness of any of the individual layers of the composite acoustic membrane may vary. For example, the thickness of the layers may be configured such that collectively the thickness of the layers provided an overall thickness of the acoustic composite membrane such that the acoustic composite membrane occupies a particular cavity or opening of the dishwasher. As another example, the relative thickness of the foam layers may vary depending on the application. In general, each of the foam layers absorbs and decelerates a portion of the sound transmitted through the layer regardless on the direction of the sound. The foam layer on either side of the vinyl layer absorbs and decelerates the sound before it reaches the vinyl layer regardless of the direction of the sound which increases the overall effectiveness of the composite acoustic membrane. In some applications, the sound coming from a particular side of the vinyl may be relatively minimal and in such case, the foam layer on that particular side may be relatively thinner than the other foam layer. It should be noted that, in some applications, it is believed that it is beneficial to manage not only the sound transmitted from inside the dishwasher to outside the dishwasher but also the sound transmitted from outside the dishwasher to the inside the dishwasher as well. Sound transmitted from outside the dishwasher to inside the dishwasher may eventually reflect back or otherwise contribute to the level of sound transmitted from the inside the dishwasher to the outside of the dishwasher.
A particular area of concern in a dishwasher in terms of noise is the toe plate. More specifically and as illustrated in
According to an embodiment, the dishwasher includes a toe plate assembly configured to reduce sound power emissions from the bottom-front area of the dishwasher. More specifically, according to the illustrated embodiment of
The toe plate assembly 300 further includes a first panel 330 of the composite acoustic membrane. The first panel 330 is attached to the access cover 320, e.g., with the use of the pressure sensitive adhesive of the composite acoustic membrane. In general, the first panel 330 is shaped and sized to be approximately the same size or larger than the access opening and is attached to the access cover 320 such that when the access cover 320 is attached the first panel 330 is substantially centered on the access opening. Although, in the illustrated embodiment, the first panel 330 of the composite acoustic membrane does not cover the entire inner panel 310, it is positioned strategically in the center of the inner panel 310. The center of the inner panel 310 is the portion of the inner panel 310 further from any supporting elements and has the highest tendency to vibrate.
The toe plate assembly 300 may include a second panel 350 of the composite acoustic membrane. The second panel 350 is positioned in front of (i.e., closer to the exterior of the dishwasher) the first panel of the composite acoustic membrane and the inner support panel. For example, as best shown in
According to the illustrated embodiment of
Another embodiment is directed to the door assembly of the dishwasher which is another area of interest in terms of transmitting sound. As shown in
As shown in
The door assembly may include a panel 480 of the acoustic composite membrane positioned within one of the cavities 462, 468. For a more specific example and according to the illustrated embodiment of
According to the illustrated embodiment of
The sound power not absorbed or converted into heat by the first, second, and third layers 482, 484, 486 may be transmitted onto the fibers of the acoustic tape layer. In particular, the panel 480 of the acoustic composite membrane includes a fourth layer 488 and the fourth layer may be a layer of the acoustic tape as described above, including the bi-directional polymer fibers. In general, the acoustic tape may be configured to provide protection and structural stability to the rest of the composite acoustic membrane. However, it is believed that the bi-directional polymer fibers may be positioned and configured to provide an additional benefit. For example, the bi-directional polymer fibers redirect a portion of the sound power level along the fibers, i.e., in four directions (up, down, left, right), where it is converted or transformed into heat. Moreover, the acoustic tape includes a reflective foil material which also reflects or refracts a portion of the sound power level. Individually and collectively, the fibers and the foil material further reduce the sound power level that transmits through the door assembly which may be perceivable to consumers
The panel 480 of the acoustic composite membrane may have a first orientation within the door assembly. For example, according to the illustrated embodiment, the acoustic tape layer 488 may be adjacent the outer panel 470 such that the acoustic tape is considered to be facing the outside environment of the dishwasher. As another example (not illustrated), in a second orientation, the acoustic tape layer is adjacent the intermediate panel such that the acoustic tape is considered to be facing the tub. In both the first and second orientation, the panel of the composite acoustic membrane may include an adhesive, such as a pressure-sensitive adhesive, for adhering the first layer to either the outer panel or the intermediate panel.
The door assembly 450 may include an additional panel of the acoustic composite membrane that is positioned within the first cavity. In other embodiments, the door assembly may include a panel of expanded polystyrene or Styrofoam® positioned within the first cavity to further help to insulate the door assembly or to provide additional support or stiffening of the door assembly.
As illustrated in
In general, the base 620 includes four panels configured to engage the perimeter of the lower end of the tub 610. The interface of the tub 610 and the base 620 define an aperture or crevice 640 extending along the perimeter of the lower end of the tub 610. The aperture 640 may be a conduit of sound generated from several sources including any fans, pumps, valves, and motors enclosed in the base 620. Moreover, the crevice 640 may also be a conduit of sound generated from the hoses extending in and out of the dishwasher, including transmitting sound back toward the dishwasher.
A further embodiment is directed to reducing the sound transmission through the aperture 640. Referring to
It is believed that the vinyl layer of the acoustic composite membrane is effective at absorbing sound at a low frequency (30-300 kHz) and each foam layer is effective at absorbing sound at a medium frequency (300-3000 kHz). It is also believed that the excess at a high frequency (3-30 MHz) is transformed into heat which dissipates in two directions along the fibers of the acoustic tape and excess noise is attenuated at the intersections of the fibers (which function as acoustic nodes).
As illustrated in
According to the embodiment illustrated in
According to the illustrated embodiment, the acoustic attenuation composite 1100 is a laminated structure that includes a first layer 1110, a second layer 1120, and a third layer 1130. The first layer 1110 may be a polystyrene foam or Styrofoam® panel that is shaped and sized to substantially cover an inner surface of the outer panel 1156 of the door assembly. The first layer 1110 may be directly behind and adjacent to the outer panel 1156. The second layer 1120 may be a mass-loaded vinyl layer that is shaped and sized substantially the same as the first layer 1100 and is directly behind and adjacent the first layer 1110. The third layer 1130 may be another mass-loaded vinyl layer. However, according to the illustrated embodiment, unlike the second layer 1120, the third layer 1130 is smaller such that the third layer 1130 covers only a central portion of the first and second layers 1110, 1120. The third layer 1130 may be positioned to be centered on the second layer 1120 and between the second layer 1120 and the intermediate panel 1154 of the door assembly.
Collectively, the first, second, and third layers 1110, 1120, 1130 may extend completely from the intermediate panel 1154 to the outer panel 1156 of the door assembly. The layers 1110, 1120, 1130 may be held in place by an interference fit between the layers 1110, 1120, 1130 and the panels 1154, 1156. In other embodiments, a pressure sensitive adhesive may be added to the second and third layers to help hold the layers together. The use of the pressure sensitive adhesive may also ease the manufacturing and assembling of the door assembly having the acoustic attenuation composite 1100.
The acoustic attenuation composite 1110 may also include a layer of the acoustic tape 1140 described above. For example and as illustrated, the acoustic tape 1140 may be applied to the top of the third layer 1140, i.e., between the third layer 1130 and the intermediate panel 1140.
In operation, as the SPL from the dishwasher vibrates, the intermediate panel 1140 of the door assembly creates structural noise that may be absorbed by the third layer. Excess noise may then be transmitted to the second layer 1120, where more of the structural noise may be absorbed and converted into heat. Excess structural noise may then vibrate the outer panel 1156 of the door assembly and exit as the residual noise out to the environment. It is believed that any residual noise will have a controlled high/low sine wave amplitude that may be more acceptable to customers. It is also believed that the fibers of the acoustic tape help to redirect and defuse a portion of the SPL.
The above embodiments describe positioning one or more panels of an acoustic composite membrane or other laminated structures configured to attenuate sound throughout the dishwasher. It is understood that one or more of the embodiments above may be combined to provide a dishwasher having the panels of the acoustic composite membrane in one or more of the following locations: (1) in front of an inner panel of a toe kick assembly; (2) behind an outer panel of the toe kick assembly; (3) within a cavity of the door assembly; (4) along an aperture defined between the tub and the base; and (5) between the front frame elements and the door assembly. The positioning and use of the panels of an acoustic composite membrane reduces the externally perceptible noise generated by the dishwasher during use including sound generated from the water splashing against the inner walls of the dishwasher and structure borne noise emitted by the drain motor, drain valve, recirculation motor, hydraulic hoses, water supply hose, and fans.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.