Abstract:
Clothes driers include a cabinet, a rotatable drum mounted inside the cabinet, and one or more vibration dumpers mounted to the rotatable drum. The vibration dampers may be mounted inside the drum, between baffles and the drum. The vibration dampers may be attached to the rotatable drum, such that a largest dimension of the vibration dampers extends in a direction of length of the rotatable drum. The vibration dumpers may be configured to shift acoustic energy generated at the front of the drum toward the rear of the drum.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application No. 62/013,615 filed on Jun. 18, 2014, titled “Vibration Damping System” which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present relates to a method and apparatus for vibration (e.g., sound) damping. 
         [0004]    2. Description of Related Art 
         [0005]    The damping of vibration of mechanical systems is of increasing importance to industry in that vibration can have a number of undesirable effects. For instance, consumers are becoming increasingly sensitive to the undesirability of sound created by vibrating systems. Automobile manufacturers have recognized the importance in the purchasing decision of many buyers of a solid thump sound when an automobile door is closed. Likewise, the quality of an appliance is sometimes gauged in part by the perception of the solidity of its construction. 
         [0006]    It has become important for the manufacturers of appliances such as clothes washers and dryers, refrigerators, microwave ovens, ovens, stoves, dishwashers, etc. to provide vibration damping on the large, flat sheet material sides of the appliances so that a consumer in making his or her purchasing decision can appreciate the quality of the product by the low frequency sound generated when the side of the appliances is hit. Also, provision of such systems can be important to reduce the noise levels produced by the appliance when such sides vibrate. This is especially true today because of the increase in homes that locate such appliances on the main living floor thereof. 
         [0007]    Sound damping systems generally operate by converting vibration energy into thermal energy. For instance, the vibration energy may be converted into thermal energy by interfacial friction, which makes it exhibit a vibration damping property. Alternatively or in addition, shear deformation may be produced within an elastic material having a small elastic modulus when it is located between a source of vibration energy and another surface or constraining layer. 
         [0008]    Pre Finish Metals Inc. provides a product called Polycore® which consists of metal outer skins surrounding a thin, viscoelastic core material. This inner core converts the mechanical energy of vibration into heat and then dissipates the heat. This combination is purported to reduce vibration generated noise at the source. Similarly, 3M provides products under the name “Scotchdamp™ vibration control systems” in which any one of a variety of adhesive layers join a constraining layer to a source of vibrating sound. The shear modulus and sound loss factors of these products depend on frequency and temperature, as well as on other factors. 
         [0009]    In addition to adhesives, magnetic materials may join a constraining layer to a source of vibratory sound. For instance, in U.S. Pat. No. 5,300,355, the disclosed vibration damping material includes a magnetic composite type damping material constructed by bonding an adhesive elastic sheet containing magnetic powder to a constraining plate such as a metal plate. In this system, it is reported that since not only is the damping material attracted by a magnetic force against a vibration source, it is also provided with a superficial adhesiveness to develop vibration damping properties over a wide range of temperatures. 
         [0010]    Domestic clothes drying machines typically comprise a rotating steel dryer drum in which clothes are tumbled as warm air is circulated through the dryer drum drying the clothes. As the articles of clothing tumble within the dryer drum, the articles fall into contact with the drum wall. Heavier articles, metal buttons and loose coins have a tendency to impact the dryer drum and create noise. 
         [0011]    U.S. Pat. No. 5,901,465 discloses a clothes dryer with a reduced noise drum. Steel bands or straps are fastened about the outside periphery of the cylindrical wall of the dryer drum to absorb noise created by articles tumbling within the dryer drum during operation. An adhesive material is laminated to the strap or band which sticks the band to the outside wall of the dryer drum by applying pressure. Baffle mounting screws passing through the dryer drum also secure ends and intermediate parts of the band to the dryer drum. 
       SUMMARY 
       [0012]    The present application discloses exemplary embodiments of clothes driers. The clothes driers include a cabinet, a rotatable drum mounted inside the cabinet, and one or more vibration dampers mounted to the rotatable drum. The vibration dumpers may have a variety of different configurations. The vibration dampers may be mounted inside the drum, between baffles and the drum. The vibration dampers may be attached to the rotatable drum, such that a largest dimension of the vibration dampers extends in a direction of length of the rotatable drum. The vibration dumpers may be configured to shift acoustic energy generated at the front of the drum toward the rear of the drum. 
         [0013]    Various objects and advantages will become apparent to those skilled in the art from the following detailed description of the invention, when read in light of the accompanying drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a clothes dryer; 
           [0015]      FIG. 2A  is a perspective view of a clothes dryer drum with a baffle and dampener separated from the drum; 
           [0016]      FIG. 2B  is a sectional view showing attachment of the baffle and dampener shown in  FIG. 2A  to the drum; 
           [0017]      FIG. 3A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0018]      FIG. 3B  is a sectional view taken along the plane indicated by lines  3 B- 3 B in  FIG. 3A ; 
           [0019]      FIG. 3C  is a sectional view taken along the plane indicated by lines  3 C- 3 C in  FIG. 3B ; 
           [0020]      FIG. 4A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0021]      FIG. 4B  is a sectional view taken along the plane indicated by lines  4 B- 4 B in  FIG. 4A ; 
           [0022]      FIG. 4C  is a sectional view taken along the plane indicated by lines  4 C- 4 C in  FIG. 4B ; 
           [0023]      FIG. 5A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0024]      FIG. 5B  is a sectional view taken along the plane indicated by lines  5 B- 5 B in  FIG. 5A ; 
           [0025]      FIG. 5C  is a sectional view showing attachment of the sound dampening system shown in  FIGS. 5A and 5B ; 
           [0026]      FIG. 6A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0027]      FIG. 6B  is a sectional view taken along the plane indicated by lines  6 B- 6 B in  FIG. 6A ; 
           [0028]      FIG. 7A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0029]      FIG. 7B  is a sectional view taken along the plane indicated by lines  7 B- 7 B in  FIG. 7A ; 
           [0030]      FIG. 8A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0031]      FIG. 8B  is a sectional view taken along the plane indicated by lines  8 B- 8 B in  FIG. 8A ; 
           [0032]      FIG. 9A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0033]      FIG. 9B  is a sectional view taken along the plane indicated by lines  8 B- 8 B in  FIG. 8A ; 
           [0034]      FIG. 10A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0035]      FIG. 10B  is a sectional view taken along the plane indicated by lines  10 B- 10 B in  FIG. 10A ; 
           [0036]      FIG. 11A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0037]      FIG. 11B  is a sectional view taken along the plane indicated by lines  11 B- 11 B in  FIG. 11A ; 
           [0038]      FIG. 12A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0039]      FIG. 12B  is a sectional view taken along the plane indicated by lines  12 B- 12 B in  FIG. 12A ; 
           [0040]      FIG. 13A  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0041]      FIG. 13B  is a sectional view taken along the plane indicated by lines  13 B- 13 B in  FIG. 13A ; 
           [0042]      FIG. 13C  is a sectional view taken along the plane indicated by lines  13 C- 13 C in  FIG. 13B ; 
           [0043]      FIG. 14A  is a cross-sectional view of an exemplary embodiment of a vibration damper; 
           [0044]      FIG. 14B  is a cross-sectional view of an exemplary embodiment of a vibration damper; 
           [0045]      FIG. 15A  is a cross-sectional view of an exemplary embodiment of a vibration damper; 
           [0046]      FIG. 15B  is a cross-sectional view of an exemplary embodiment of a vibration damper; 
           [0047]      FIG. 16  is a perspective view of an exemplary embodiment of a stiffened vibration damper; 
           [0048]      FIG. 17  is a side view of an exemplary embodiment of a stiffened vibration damper; 
           [0049]      FIG. 18  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; 
           [0050]      FIG. 19  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system; and 
           [0051]      FIG. 20  illustrates an exemplary embodiment of a clothes dryer drum having an exemplary embodiment of a sound dampening system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0052]    The present invention will now be described with occasional reference to the specific embodiments of the invention. This invention may, however, be embodied in 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 be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0053]    Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
         [0054]    Unless otherwise indicated, all numbers expressing quantities of dimensions such as length, width, height, and so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invention. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements. 
         [0055]    Referring to  FIG. 1  a clothes dryer  10  is illustrated to show some of the basic details of the construction. The dryer  10  may be heated by gas or electricity. The dryer  10  includes a cabinet or housing  12  that includes a control panel  14 . A rotating drum  16 , motor  18  and blower  20  are housed within the cabinet  12 . The cabinet  12  has front wall  25  with a door  21  to give the user access to the drum  16  through an access opening  23 . The drum  16  is mounted in the cabinet  12  for rotation about its central axis. The motor  18  is arranged to drive the drum by means of belt  22 . Heated air is forced into the drum by the blower  20  through a vent  29  to extract moisture from clothes that tumble in the drum  16 . The illustrated vent  29  and drum  16  configuration is one of many possible configurations and is not intended to limit the present application in any way. 
         [0056]    Referring to  FIG. 2 , in an exemplary embodiment, the drum  16  is provided with a set of baffles  24 . The baffles  24  can be provided in a wide variety of different configurations. In the illustrated embodiments, the baffles  24  extend substantially the entire length L DRUM  of the drum. In other exemplary embodiments, the baffles  24  may extend about ½ the length L DRUM  of the drum  16 . For example, separate, shorter baffles may be provided on each side of the groove  21 . In one exemplary embodiment, four baffles having about ½ the length L DRUM  of the drum can be provided, with two diametrically offset in the front and two diametrically offset in the back. These front and rear “½ baffles” can be offset from one another by 90 degrees. The dampers  100  disclosed herein are equally applicable to the “½ baffles” as they are to the illustrated full length baffles. 
         [0057]    The baffles  24  can take a wide variety of different forms. In one exemplary embodiment, the baffles  24  are each a substantially hollow and are molded from plastic. A wide variety of different plastics can be used. Any plastic that can withstand the temperatures inside the drum  16  during operation of the dryer  10  and can withstand impact by clothes and other articles inside the drum  16  can be used to construct the baffles  24 . Examples of plastic materials for the baffle  24  include, but are not limited to, vinyl, polypropylene, and NORYL, trademark of General Electric Company. The baffle  24  may have a variety of different shapes and sizes. In an exemplary embodiment, three or more equally circumferentially spaced baffles are provided. In another exemplary embodiment, baffles are omitted or are substantially omitted. In one exemplary embodiment, the baffle is slightly curved so as to encourage the clothes to tumble toward the center of the drum  16  during a drying operation. The baffle  24  may be mounted to the drum  16  in a wide variety of different ways. In one exemplary embodiment, the baffle  24  is mounted by bolts or screws  200  to an inside surface  26  of a cylindrical drum sidewall  28 . 
         [0058]    The drum  16  can be driven in a wide variety of different ways. In one exemplary embodiment, the drive belt  22  is disposed around the drum  16 . The drive belt  22  is driven by the motor  18  to rotate the drum  16  inside the cabinet  12 . The drive belt  22  may be disposed around the drum in a wide variety of different ways. In one exemplary embodiment, an optional groove  21  receives the belt. The optional belt receiving groove can take a wide variety of different forms. For example, a circumferential indentation may be formed in the cylindrical drum sidewall  28  to define the groove  21  (see  FIG. 4A ). In another exemplary embodiment, struts or webs may be provided on an outside surface  32  of the cylindrical sidewall  28  of the drum to define a belt receiving groove  21 . 
         [0059]    In an exemplary embodiment, an appliance, such as the dryer  10  illustrated by  FIG. 1  is provided with one or more vibration dampers  100 . The vibration damper can take a wide variety of different forms and can be applied to the appliance in a wide variety of different ways. For example, the vibration damper  100  may be a frictional type damper, a free layer type damper, or a constrained layer type damper. A frictional type damper may be an underlayment made of foam or fibers. 
         [0060]      FIGS. 14A and 15A  illustrate exemplary embodiments of free layer type damper. The free layer type damper includes a layer  1413  of viscoelastic material on the surface of the component with vibration that is being damped (the dryer drum  16  in  FIGS. 14A and 15A ). The layer  1413  of damping material is adhered to the surface of a structure, such as the dryer drum  16 . Energy is dissipated as a result of extension and compression of the damping material layer  1413  when the base structure (dryer drum  16  in the example) is flexing during vibration. The damping is dependent on the composition of a damping material of the free layer damper and increases with damping layer thickness. The viscoelastic material of the may be asphaltic, such as pressure sensitive asphaltic adhesive, magnetic, and/or Butyl, such as pressure sensitive adhesive and non-adhesive butyl. The viscoelastic material may be sprayed on the structure, such as the drum  16  or the viscoelastic material may be pre-formed and applied to the structure. 
         [0061]      FIGS. 14B and 15B  illustrate exemplary embodiments of constrained layer type damper. The constrained layer type damper includes a layer  1413  of viscoelastic material on the surface of the component with vibration that is being damped (the dryer drum  16  in  FIGS. 14B and 15B ) and a constraining layer  1412  on the viscoelastic material. The layer  1413  of damping material is affixed to the surface of a structure, such as the dryer drum  16 . A “sandwich” is formed by laminating a damping layer in between the structure, such as the dryer drum, and the constraining layer. When the system flexes during vibration, shear strains develop in the damping layer and energy is lost through shear deformation of the layer  1413  of viscoelastic material. Varying layer thickness ratios permits optimizing system loss factors for various temperatures without changing the layer  1413  of viscoelastic material composition. Examples of constrained layer dampers include, but are not limited to, conformable constrained layer (CCL) dampers, patch constrained layer dampers, and aluminum backed butyl constrained layer dampers. 
         [0062]    Referring to FIGS.  2  and  3 A- 3 C, in one exemplary embodiment, a vibration damper  100  is provided between each baffle  24  and the inside surface  26  of the drum  16 . Referring to  FIGS. 3B and 3C , in an exemplary embodiment a perimeter  300  of the vibration damper  100  is sized and shaped to match a size and shape of a perimeter  302  of a base  304  of the baffle. As such, a smooth transition is provided from the inside surface  26  to the perimeter  300  of the vibration damper  100  to the perimeter  302  of the base  304  of the baffle  24 . This smooth transition prevents any snagging of clothes on the vibration damper  100  or the base  304  of the baffle  24 . In one exemplary embodiment, a bottom surface  306  of the damper  100  is contoured to match the contour of the inside surface  26  of the drum  16 . For example the bottom surface  306  of the damper  100  may be curved across its width W (see  FIG. 3B ) to match the curvature of the inside surface  26  of the drum  16 . 
         [0063]    Any of the vibration dampers  100  and the baffle  24  disclosed by the present application can be secured to the drum  24  in a wide variety of different ways. In the exemplary embodiment illustrated by  FIGS. 2A and 2B , the vibration damper  100  is secured to the drum  16  with the same fasteners  200  that secure the baffle  24  to the drum  24 . For example, during assembly, each vibration damper  100  is placed between a baffle  24  and the inside surface  26  of the drum  16 . Referring to  FIG. 2B , the vibration damper  100  is aligned with the baffle  24  and apertures  42  in the vibration damper  100  are aligned over apertures  43  through the drum  16 . A securing screw  200  extends through the aperture  43  in the drum  16 , through the aperture  42  in the vibration damper  100 , and threads into a mounting portion  52  of the baffle  24  to secure both the baffle  24  and the vibration damper  100  to the drum  16 . 
         [0064]      FIGS. 4A-4C  illustrate an exemplary embodiment where the drum  16  includes the optional groove  21  for the belt  26 . Referring to  FIGS. 4B and 4C , in an exemplary embodiment a perimeter  300  of the vibration damper  100  is sized and shaped to match a size and shape of a perimeter  302  of a base  304  of the baffle. In this embodiment, the length L D  of the vibration damper  100  matches or substantially matches the length L B  of the baffle  24 , even though the drum  16  includes the groove. A smooth transition is provided from the inside surface  26  to the perimeter  300  of the vibration damper  100  to the perimeter  302  of the base  304  of the baffle  24 . This smooth transition prevents any snagging of clothes on the vibration damper  100  or the base  304  of the baffle  24 . In one exemplary embodiment, a bottom surface  306  of the damper  100  is contoured to match the contour of the inside surface  26  of the drum  16 . For example the bottom surface  306  includes a groove  400  that matches the contour of an annular projection  402  on the inside surface  26  of the drum that is created by forming the groove  21  in the outside surface  32  of the drum. The damper  100  may also optionally be curved across its width W to match the curvature of the inside surface  26  of the drum  16 . 
         [0065]      FIGS. 5A-5C  illustrate an exemplary embodiment where dampers  100  that extend along a length L DRUM  of the drum  16  are secured to the outside surface  32  of the drum  16 . In one exemplary embodiment, a vibration damper  100  is provided on the outside surface  32  of the drum  16 , behind each baffle. In the example illustrated by  FIGS. 5A and 5B , the dampers are positioned on the outside surface  32  of the drum  16  between the access opening  23  and the belt groove  21 . 
         [0066]    Referring to  FIGS. 5B and 5C , in an exemplary embodiment a perimeter  300  of the vibration damper  100  on the outside surface  32  need not be sized and shaped to match a size and shape of a perimeter  302  of a base  304  of the baffle. The shape and size of the vibration damper  100  can be adjusted or tuned to provide an appropriate amount of vibration in selected locations of the drum  16 . In the example illustrated by  FIGS. 5B and 5C , the width of the vibration damper  100  is greater than the width of the base  304  of the baffle  24 . In other exemplary embodiments, the width of the vibration damper  100  can match the width of the width of the base  304  of the baffle or the width of the vibration damper  100  can be less than the width of the base  304  of the baffle. Further, the size of the vibration damper  100  can vary along the length of the drum. For example, the vibration damper  100  may have a wider portion toward the access opening  23 , where sound is most likely to emanate, and a narrower portion that is further away from the access opening  23 . This provides more damping where it is needed most (near the front of the dryer  10 ) and less where it may not needed as much (toward the rear of the dryer). In some exemplary embodiments, the length of the damper  100  (in the direction of the length L DRUM ) is greater than the width W of the damper  100 . In other exemplary embodiments, the length of the damper  100  (in the direction of the length L DRUM ) is less than the width W of the damper  100 . The dampers  100  can also have different shapes and sizes to further tune the vibration dampening. 
         [0067]    In one exemplary embodiment, a bottom surface  306  of the damper  100  is contoured to match the contour of the outside surface  32  of the drum  16 . For example the bottom surface  306  of the damper  100  may be curved across its width W to match the curvature of the outside surface  32  of the drum  16 . 
         [0068]    In the exemplary embodiment illustrated by  FIG. 5C , the vibration damper  100  is secured to the drum  16  with the same fasteners  200  that secure the baffle  24  to the drum  16 . Any of the vibration dampers  100  and baffles disclosed by this application can be secured to the drum  24  in this manner. For example, during assembly, each vibration damper  100  is placed against the outside surface  32  of the drum  16  and the baffle  24  is placed against the inside surface  26  of the drum. The apertures  42  in the vibration damper  100  are aligned over apertures  43  through the drum  16 . A securing screw  46  extends through the aperture  42  in the vibration damper  100 , through the aperture  43  in the drum  16 , and threads into a mounting portion  52  of the baffle  24  to secure both the baffle  24  and the vibration damper  100  to the drum  16 . 
         [0069]      FIGS. 6A and 6B  illustrate an exemplary embodiment that is similar to the embodiment illustrated by  FIGS. 5A-5C , except the dampers  100  are positioned on the outside surface  32  of the drum  16  between the belt groove  21  and a rear end  600  of the drum  16 . 
         [0070]      FIGS. 7A and 7B  illustrate an exemplary embodiment that is similar to the embodiment illustrated by  FIGS. 5A-5C , except the dampers  100  are positioned both between the access opening  23  and the belt groove  21  and between the belt groove  21  and the rear end  600  of the drum  16 . The dampers can be positioned in a wide variety of different configurations and can have a variety of different shapes and sizes. In the example illustrated by  FIGS. 7A and 7B , the dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can have a different size than the dampers  100  between the access opening  23  and the belt groove  21 . For example, the dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can be smaller, larger, and/or have a different shape than the dampers  100  between the access opening  23  and the belt groove  21 . 
         [0071]      FIGS. 8A and 8B  illustrate an exemplary embodiment similar to the embodiment illustrated by  FIGS. 5A-5C , except two dampers  100  are positioned behind two baffles  24  between the access opening  23  and the belt groove  21  and two dampers  100  are positioned behind two baffles  24  between the belt groove  21  and the rear end  600  of the drum  16 . The dampers can be positioned in a wide variety of different configurations and can have a variety of different shapes and sizes. In the example illustrated by  FIGS. 8A and 8B , the dampers  100  between the access opening  23  and the belt groove  21  are diametrically opposed. The dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  are also diametrically opposed and are offset by 180 degrees from the dampers  100  between the access opening  23  and the belt groove  21 . The dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can have a different size than the dampers  100  between the access opening  23  and the belt groove  21 . For example, the dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can be smaller, larger, and/or have a different shape than the dampers  100  between the access opening  23  and the belt groove  21 . 
         [0072]      FIGS. 9A and 9B  illustrate an exemplary embodiment where dampers  100  that extend along a length L DRUM  of the drum  16  are secured to the outside surface  32  of the drum  16 . In one exemplary embodiment, the vibration dampers  100  is provided on the outside surface  32  of the drum  16 , offset from the baffles. In the example illustrated by  FIGS. 9A and 9B , the dampers  100  are positioned on the outside surface  32  of the drum  16  between the access opening  23  and the belt groove  21 . 
         [0073]    In an exemplary embodiment a perimeter  300  of the vibration damper  100  on the outside surface  32  may have a wide variety of different configurations. The shape and size of the vibration damper  100  can be adjusted or tuned to provide an appropriate amount of vibration in selected locations of the drum  16 . In the example illustrated by  FIG. 9B , the width of the vibration damper  100  is greater than the width of the base  304  of the baffle  24 . In other exemplary embodiments, the width of the vibration damper  100  can match the width of the width of the base  304  of the baffle or the width of the vibration damper  100  or can be less than the width of the base  304  of the baffle. Further, the size of the vibration damper  100  can vary along the length of the drum. For example, the vibration damper  100  may have a wider portion toward the access opening  23 , where sound is most likely to emanate, and a narrower portion that is further away from the access opening  23 . This provides more damping where it is needed most (near the front of the dryer  10 ) and less where it may not needed as much (toward the rear of the dryer). The dampers  100  can also have different shapes and sizes to further tune the vibration dampening. 
         [0074]    In the exemplary embodiment illustrated by  FIG. 9B , a bottom surface  306  of the damper  100  is contoured to match the contour of the outside surface  32  of the drum  16 . For example the bottom surface  306  of the damper  100  may be curved across its width W to match the curvature of the outside surface  32  of the drum  16 . In other exemplary embodiments, the bottom surface  306  is not contoured. In the exemplary embodiment illustrated by  FIGS. 9A and 9B , the vibration dampers  100  may be secured to the drum  16  with fasteners, adhesive, welding, and the like. 
         [0075]      FIGS. 10A and 10B  illustrate an exemplary embodiment that is similar to the embodiment illustrated by  FIGS. 9A and 9B , except the dampers  100  are positioned on the outside surface  32  of the drum  16  between the belt groove  21  and a rear end  600  of the drum  16 . 
         [0076]      FIGS. 11A and 11B  illustrate an exemplary embodiment that is similar to the embodiment illustrated by  FIGS. 9A and 9B , except the dampers  100  are positioned both between the access opening  23  and the belt groove  21  and between the belt groove  21  and the rear end  600  of the drum  16 . The dampers can be positioned in a wide variety of different configurations and can have a variety of different shapes and sizes. In the example illustrated by  FIGS. 11A and 11B , the dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can have a different size than the dampers  100  between the access opening  23  and the belt groove  21 . For example, the dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can be smaller, larger, and/or have a different shape than the dampers  100  between the access opening  23  and the belt groove  21 . 
         [0077]      FIGS. 12A and 12B  illustrate an exemplary embodiment similar to the embodiment illustrated by  FIGS. 9A and 9B , except two dampers  100  are positioned between the access opening  23  and the belt groove  21  and two dampers  100  are positioned between the belt groove  21  and the rear end  600  of the drum  16 . The dampers can be positioned in a wide variety of different configurations and can have a variety of different shapes and sizes. In the example illustrated by  FIGS. 12A and 12B , the dampers  100  between the access opening  23  and the belt groove  21  are diametrically opposed. The dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  are also diametrically opposed and are offset by 180 degrees from the dampers  100  between the access opening  23  and the belt groove  21 . The dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can have a different size than the dampers  100  between the access opening  23  and the belt groove  21 . For example, the dampers  100  between the belt groove  21  and the rear end  600  of the drum  16  can be smaller, larger, and/or have a different shape than the dampers  100  between the access opening  23  and the belt groove  21 . 
         [0078]    The embodiments illustrated by  FIGS. 3A-12B  can be combined in a variety of different ways. For example, dampers  100  may be placed both inside and outside the drum  16 , and/or behind and offset from the from the baffles  24 . Any of the configurations illustrated by  FIGS. 3A-12B  can be combined with any of the other configurations to form additional damper configurations. 
         [0079]      FIGS. 13A-13C  illustrate and exemplary embodiment where the drum  16  is contoured. The drum  16  may be contoured in a in a wide variety of different ways. In the illustrated exemplary embodiment, the drum  16  is dimpled. The dimpled drum  1300  includes a pattern of dimples  1302  or indentations. The dimpled drum may be made from a wide variety of different materials. For example, the dimpled drum may be steel, such as stainless steel. The dimples  1302  and dimple patterns can take a wide variety of different forms. The dimples  1302  and the pattern of dimples can be uniform and/or non-uniform. In one exemplary embodiment, a stainless steel drum has a dimple pattern with deeper dimples in the middle of the drum  16  than on the front and rear portions of the drum. 
         [0080]    Referring to  FIG. 13C , in an exemplary embodiment the damper  100  is contoured to match the contour of the drum  16 . For example, the illustrated damper  100  includes projections  1310  that match the contour of the pattern of dimples  1302 . Dampers  100  that match the contour of the drum can be applied to the drum  16  in any of the configurations contemplated by  FIGS. 3A-12B . The dampers  100  may be made to match the contour of the drum  16  with dimples  1302  in a wide variety of different ways. In one exemplary embodiment, an adhering layer  1413  may be spray applied to the drum to fill in the dimples  1302  and thereby match the contour of the dimpled drum  16 . In another exemplary embodiment, the layer  1413  is made from a deformable material and the constraining layer  1412  is drawn down by the fasteners to press the layer  1413  into the dimples. 
         [0081]    The dampers  100  can take a wide variety of different forms. One damper that can be used is a Polycore® from Pre Finish Metals Inc. Polycore® consists of metal outer skins surrounding a thin, viscoelastic core material. This inner core converts the mechanical energy of vibration into heat and then dissipates the heat. Another damper that can be used is Scotchdamp™ vibration control systems from 3M. In the Scotchdamp™ vibration control systems any one of a variety of adhesive layers joins a constraining layer to a source of vibrating sound. In addition to adhesives, magnetic materials may join a constraining layer to a source of vibratory sound. For instance, in U.S. Pat. No. 5,300,355, the disclosed vibration damping material includes a magnetic composite type damping material constructed by bonding an adhesive elastic sheet containing magnetic powder to a constraining plate such as a metal plate. U.S. Pat. No. 5,300,355 is incorporated herein by reference in its entirety. 
         [0082]    U.S. Pat. No. 5,855,353 discloses examples of dampers  100  that can be used in the embodiments of the present application. U.S. Pat. No. 5,855,353 is incorporated herein by reference in its entirety. Referring to  FIGS. 14B and 15B , in an exemplary embodiment the damper  100  includes a constraining layer  1412  and an adhering layer  1413 . Referring to  FIGS. 14A and 15A , in some exemplary embodiments, the constraining layer  1412  is omitted. In the illustrated embodiment, the constraining layer  1412  is an elongated metal bar or rectilinear plate, but can be shaped as a circular, ovoid, square, irregular, etc. any shape or contoured as desired. The constraining layer  1412  can include an appropriate configuration to assist in stiffening the drum  16 . Such a stiffening configuration of the constraining layer  1412  can comprise bent edges  1416  running the length or width of a flat constraining layer  1412  (See  FIG. 17 ) or a bend  1414  running the length of the constraining layer  1412  (See  FIG. 16 ) to provide greater rigidity due to the angled surfaces of the cross-section of the constraining layer  1412 . The bend  1414  can be chevron shaped as shown, or other shapes such as arcuate, rectilinear, etc., shaped may be used if desired. 
         [0083]    Any suitable material can be used for the constraining layer  1412  provided the material has a large elastic modulus at least in one direction compared to the surface of the drum  16  to which it is applied. Stated in other terms, the constraining layer  1412  should have relatively higher flexural rigidity. In one exemplary embodiment, the constraining layer  1412  has a flexural rigidity that is at least eighty percent of the flexural rigidity of the drum sidewall. In one exemplary embodiment, the constraining layer  1412  has a flexural rigidity that is at as high as the flexural rigidity of the drum sidewall. In one exemplary embodiment, the constraining layer  1412  has a flexural rigidity that is higher than the flexural rigidity of the drum sidewall. In an exemplary embodiment, the constraining layer  1412  resists flexure of the drum  16  to which it is applied, thereby causing shear forces to develop in the adhering layer  1413  to thus convert vibration into heat energy. For instance, the constraining layer  1412  may have a large elastic modulus such as a plate made of sheet metal, iron, aluminum, stainless steel, copper, etc., a plastic plate made of phenol resin, polyamide, polycarbonate, polyester, etc., a fiber reinforced plastic plate fabricated by reinforcing the plastic plate using fiber such as glass fiber, carbon fiber, etc., or an inorganic rigid plate such as slate plate, hydrated calcium silicate plate, a plaster board, a fiber mixed cement plate, a ceramic plate, etc., or an organic rigid plate including asphalt, fiber impregnated with asphalt, wood, etc. 
         [0084]    As shown in  FIGS. 14B and 15B , the adhering layer  1413  is interposed between the constraining layer  1412  and the source of vibration such as the drum  16 , such that it acts both to adhere the constraining layer  1412  to the drum  16  and damp the vibration of the drum  16 . In the example illustrated by  FIG. 14B , the adhering layer  1413  is composed of a viscosity enhancing material  1421  and an adhesive  1422 . The viscosity enhancing material  1421  enhances the viscosity of the adhesive and thereby creep resistance, but also reinforces the adhesive and thereby increases the adhesive&#39;s resistance to shock and shearing forces. In the example illustrated by  FIG. 15B , the adhering layer  1413  is composed of an adhesive  1422  and the viscosity enhancing material  1421  is omitted. 
         [0085]    The adhesive  1422  can take a wide variety of different forms. In one exemplary embodiment, the adhesive  1422  is preferably a viscoelastic material which converts vibration into heat energy by shear forces developed within the viscoelastic material. Any suitable viscoelastic adhesive material can be used if it remains viscous after curing. For instance, the adhesive can be any one or more of the following adhesives: a pressure sensitive hot or cold melt adhesive, an acrylic based adhesive such as acrylic viscoelastic polymers, pressure sensitive damping polymers, adhesive epoxy resins, urea resins, melamine resins, phenol resins, vinyl acetates, cyanoacrylates, urethanes, synthetic rubbers, etc. The adhesive can be, for example, any one of a variety of commercial adhesives such as the acrylic adhesive A-1115 from Avery-Dennison, the acrylic adhesive MACtac™ XD-3780 from Morgan Adhesives, the synthetic rubber based hot melt adhesive R-821 from The Reynolds Co., or the acrylic adhesive V-514 from Venture Tape. 
         [0086]    The viscosity enhancing material  1421  of the adhering layer  1413  generally reduces the fluidity of the resulting adhesive layer, thereby generally reducing the amount of both static and dynamic creep exhibited within the vibration damping system. The viscosity enhancing material  1421  may include one or more of the following exemplary materials: organic fibers including cellulose, carbon fiber, asbestos, and inorganic fibers including glass fiber, steel wool, synthetic fibers, etc. 
         [0087]    The viscosity enhancing material  1421  provides a structure interposed between the vibration generating source such as the drum  16  of the dryer and the constraining layer  1412 . This structure permits the drum sidewall  28  and the constraining layer  1412  to move relative to one another within confines, but increases the viscosity (i.e., resistance to flow) of the adhering layer  1413  so that permanent shifts between the constraining layer  1412  and the drum sidewall  28  are reduced. In other words, the constraining layer  1412  in general does not creep relative to the drum sidewall  28  as much as in an identical damping system that doesn&#39;t include the viscosity enhancing material  1421 . 
         [0088]    In one exemplary embodiment, the viscosity enhancing material  1421  of the adhering layer  1413  is a cellulose material, the fibers of which are dimensioned and matted to permit penetration of the adhesive in its liquid state into the cellulose carrier material, which may be accomplished by soaking the cellulose material in the adhesive, by pressurized extrusion, by rolling, or by any other suitable method. The penetration can be within microns or throughout the cellulose material. 
         [0089]    The adhering layer  1413  is produced by applying an adhesive  1422  in a liquid state to the viscosity enhancing material  1421  and curing the adhesive  1422  to form an adhesive coated core. A number of processes can be used to apply the adhesive  1422  to the viscosity enhancing material  1421  or to carrier materials. For instance, a roll coat process (metered adhesive liquid is applied to one or both of two or more opposing rollers between which a core, e.g., the viscosity enhancing material, passes), spray coating, brush coating, knife coating, foam (stable bubbles) or froth (the bubbles of which dissipate to leave a thin coat) coating in the form of applying mechanically or chemically agitated adhesives, curtain coating, slot die or extruded coating (with the carrier or viscosity enhancing material passing through a slot in which adhesives are injected), or calendaring, for example. Appropriate release films may be formed or placed on the major surfaces (top and/or bottom) of the adhesive coated core or adhering layer  1413  in a known fashion. 
         [0090]    In some exemplary embodiments, the adhering layer  1413  of the embodiments illustrated by  FIGS. 14A ,  14 B,  15 A, and  15 B is replaced with a non-adhesive material. A wide variety of different non-adhesive materials can be used. In one exemplary embodiment, the non-adhesive layer is a viscoelastic material which converts vibration into heat energy by shear forces developed within the viscoelastic material or an elastic material. Any suitable viscoelastic adhesive material can be used. Examples of suitable non-adhesive materials include, but are not limited to, ethylene vinyl acetate (EVA), and blends of EVA, and other polymers, including blends of EVA with one or more of polypropylene, nitrile rubber, and ethylene-styrene interpolymers. Additional examples include, but are not limited to, acrylics, such as acrylic viscoelastic polymers, epoxy, ureas, melamines, phenols, vinyl acetates, cyanoacrylates, urethanes, synthetic rubbers, etc. 
         [0091]    Referring to  FIGS. 18 and 19 , in one exemplary embodiment the dampers  100  are configured to drive acoustic energy from one area of the dryer  10  to another area of the dryer. For example, the dampers  100  can be configured to drive acoustic energy generated at the front of the drum  16  toward the rear of the drum (See Arrow  1800  in  FIGS. 18 and 19 ). This shifting of the acoustic energy can be accomplished in a wide variety of different ways. Damper features that drive acoustic energy from one location to another location are referred to as “acoustic shifting features”  1900  in this application. The following are examples of acoustic shifting features:
       Portions of the damper  100  may be stiffer than other portions of the damper (for example due to bending—See  FIGS. 16 and 17 );   Portions of the damper may be larger than other portions of the damper;   Portions of the damper may be thicker than other portions of the damper;       
 
         [0095]    Portions of the damper may be denser or heavier than other portions of the damper and/or; 
         [0096]    Portions of the damper may be made from other materials than other portions of the damper. 
         [0097]    In the example illustrated by  FIG. 18 , acoustic shifting features  1900  are provided on a front portion  1902  of the dampers  100  that is positioned close to the access opening  23  of the drum  16 . The acoustic shifting features  1900  force the vibration energy toward the back end  1904  of the drum  16 . In one exemplary embodiment, the acoustic shifting features  1900  make a front portion  1912  of the drum stiffer than the back end  1914  of the drum  16 . The stiffer front portion  1912  of the drum  16  forces the vibration energy toward the less stiff back end  1914  of the drum  16 . 
         [0098]    In the example illustrated by  FIG. 19 , acoustic shifting features  1900  are provided on the dampers  100  that are positioned between the access opening  23  and the belt groove  21  of the drum  16 . In the example illustrated by  FIG. 19 , the acoustic shifting features  1900  are patterned to control the shifting of the vibration energy. The acoustic shifting features  1900  can be patterned in a wide variety of different ways. In one exemplary embodiment, the acoustic shifting features are configured to aggressively drive the vibration energy at the front end  1902  of the drum  16  rearward and then less aggressively drive the vibration energy toward the rear of the drum as the distance between the front of the drum and the rear of the drum increases. This can be accomplished in a wide variety of different ways. In the illustrated embodiment, the acoustic shifting features  1900   a  and  1900   b  that are closer to one another than the acoustic shifting features  1900   b  and  1900   c . In one exemplary embodiment, the acoustic shifting features  1900  make the front end  1902  of the drum  16  most stiff and then gradually less stiff toward the rear of the drum as the distance between the front of the drum and the rear of the drum increases. This gradual change in stiffness can be accomplished in a wide variety of different ways. For example, more closely spaced bends closest to the front of the drum and bends spaced farther apart as the distance from the front of the drum increases, the width of the damper tapers as the distance from the front of the drum increases, the thickness of the damper tapers as the distance from the front of the drum increases, the weight of the damper declines as the distance from the front of the drum increases, and portions of the damper that are farther away from the front of the drum are made from less stiff materials. 
         [0099]    In the examples illustrated by  FIGS. 18 and 19  the acoustic shifting features  1900  are illustrated as extending generally in the direction of the circumference of the drum  16 .  FIG. 20  illustrates an exemplary embodiment where the acoustic shifting features extend along the length L DRUM  of the drum. It should be appreciated from  FIGS. 18-20  that the acoustic shifting features can extend in any direction and can have any configuration. 
         [0100]    The dampers  100  disclosed by the present application can be used on any vibrating system which requires damping on any surface. For instance, the dampers  100  can be used to dampen vibration of any surface of a cabinet or housing, drum, moving part, etc. of any machine. Examples of applications for the dampers  100  disclosed by the present application include, but are not limited to, clothes washing machines (for example, a tub, basket, motor, or other moving part and/or a cabinet or housing or other stationary part of the clothes washing machine), air conditioners (for example, a compressor, vent, housing, or other part of the compressor and/or a cabinet, housing, heat exchange coil or other stationary part of the air conditioner), components of heating ventilation and air conditioning systems (for example, fans, blowers, ducts, plenums, and the like), refrigerators (for example, fans, compressors, or other moving parts and/or a cabinet, housing, heat exchange coil or other stationary part of the refrigerator), fans, squirrel cages of fans, small appliances (for example, a motor or other moving part and/or a cabinet or housing or other stationary part of the appliance), blenders (for example, a motor or other moving part and/or a housing or other stationary part of the blender), vacuums (for example, a motor, brush, impeller or other moving part and/or a housing or other stationary part of the vacuum), mixers (for example, a motor or other moving part and/or a housing or other stationary part of the mixer), white goods (for example, a motor or other moving part and/or a housing or other stationary part of the white good), industrial equipment (for example, a motor or other moving part and/or a housing or other stationary part of the industrial equipment), generators (for example, a motor or other moving part and/or a housing or other stationary part of the white good), light sets, articles with metal that vibrates, mufflers (for example, the external housing or internal components of the muffler), engines, such as gasoline and diesel engines, engine accessories, such as radiators, pumps, intake manifolds, exhaust manifolds, air conditioners, heaters, heater blowers, and the like, industrial grade food processing equipment (for example, drums, mixers and the like), commercial and residential equipment and devices, panels of automobile doors, trunks, hoods, etc. and aeronautical applications, and electronic devices. The present invention can be applied anywhere vibration or sound damping is appropriate. 
         [0101]    The above description of specific embodiments has been given by way of example. From the disclosure given, those skilled in the art will not only understand the general inventive concepts and attendant advantages, but will also find apparent various changes and modifications to the structures and methods disclosed. For example, the general inventive concepts are not typically limited to any particular application or damper configuration. Thus, for example, use of the inventive concepts on all types of devices needing vibration and/or sound deadening, are within the spirit and scope of the general inventive concepts. As another example, although the embodiments disclosed herein have been primarily directed to a dryer, the general inventive concepts could be readily extended to any application which could benefit from the damper configurations disclosed herein. It is sought, therefore, to cover all such changes and modifications as fall within the spirit and scope of the general inventive concepts, as described and claimed herein, and equivalents thereof. 
         [0102]    Several exemplary embodiments of vents are disclosed by this application. Vibration dampers and devices with vibration dampers in accordance with the present invention may include any combination or subcombination of the features disclosed by the present application. 
         [0103]    While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Still further, while specifically shaped features have been shown and described herein, other geometries can be used including elliptical, polygonal (e.g., square, rectangular, triangular, hexagonal, etc.) and other shapes can also be used. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures can be made from such details without departing from the spirit or scope of the applicant&#39;s general inventive concept.