Abstract:
A rotary damper includes a housing and a rotor rotatable in the housing. A clutch is movable toward and away from the housing when said rotor is rotated in first and second directions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present regular United States Patent Application claims the benefits of U.S. Provisional Application Ser. No. 60/736,549, filed on Nov. 14, 2005 and U.S. Provisional Application Ser. No. 60/774,277, filed Feb. 13, 2006. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention pertains generally to movement dampers and, more particularly to rotary dampers having a rotor rotatable in a housing to provide damping resistance for the movement of an object.  
       BACKGROUND OF THE INVENTION  
       [0003]     Movement dampers of various types are known in a variety of assemblies and applications to control the movement of assembly components. For example, movement dampers are known for controlling the movement in at least one direction of a drawer or door in furniture, cabinets and appliances. In the automotive field it is known to use dampers on glove box and counsel doors as well as other doors and closures for bins, storage areas and the like.  
         [0004]     In some situations, damping control is required only in one direction. So-called one-way dampers provide damping resistance when operated in one direction, but provide little or no damping resistance when operated in another direction.  
         [0005]     Various types of rotary dampers are known for the above purposes, including for use as one-way dampers. A known design for rotary one-way dampers includes a housing and a rotor rotatable in the housing, with a shaft from the rotor extending outwardly of the housing for receiving a gear thereon to engage a gear on the device being controlled. In some rotary dampers of this type, a viscous fluid is provided in a sealed housing, and damping performance is provided by resistance of the fluid to rotation of the rotor within the housing. Various rotor configurations as well as housing configurations are used for porting the fluid in the housing to control the damping performance.  
         [0006]     It also is known to use mechanical resistance in the housing without the use of damping fluid. Mechanical one-way dampers have been complex, often requiring springs and numerous parts to selectively engage or disengage cooperating components of the damper system. Such structures add complexity and cost to the overall assembly.  
         [0007]     Accordingly, it is desirable to have a relatively simple rotary damper that automatically provides damping performance when rotated in one direction and little or no damping performance and only minimal resistance when rotated in an opposite direction, without the need for complex and expensive structure for engaging components.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a rotary damper having an internal clutch mechanism whereby the damper is rendered effective or ineffective for damping, depending on the direction the rotor is rotated.  
         [0009]     In one aspect thereof, the present invention provides a rotary damper with a housing having a housing inner surface, a rotor rotatable in the housing and a clutch between the rotor and the housing surface. One of the rotor and the clutch has a lobe facing the other of the rotor and the clutch. The other of the rotor and the clutch has a slot opening toward the lobe. The lobe is positioned at a first depth in the slot when the rotor is rotated in one direction, with a gap established between the clutch and the housing inner surface. The lobe is positioned at a second depth in the slot more shallow than the first depth when the rotor is rotated in a second direction, with the gap being one of reduced and eliminated.  
         [0010]     In another aspect thereof, the present invention provides a rotary damper with a housing, a rotor axially rotatable in the housing, and a plurality of clutch leaves disposed between the housing and the rotor. The leaves are engaged with the rotor and are disposed radially outward against the housing when the rotor is rotated in a first direction and radially inward away from the housing when the rotor is rotated in a second direction.  
         [0011]     In a still further aspect thereof, the present invention provides a rotary damper with a housing having a bottom, a rotor having a rotor plate rotatable in the housing in a substantially fixed position axially in the housing, and a clutch plate engaged with the rotor for axial movement in the housing. The clutch plate is disposed at first and second distances from the bottom when the rotor is rotated in first and second directions, respectively.  
         [0012]     An advantage of the present invention is providing a one-way rotary damper that adjusts automatically for providing damping performance in only one direction of rotor rotation.  
         [0013]     Another advantage of the present invention is providing a one-way rotary damper that is simple to manufacture, assemble and use.  
         [0014]     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is an exploded view of a rotary damper in accordance with the present invention;  
         [0016]      FIG. 2  is a cross-sectional view of the rotary damper shown in  FIG. 1  illustrating operation of the damper to provide damping performance;  
         [0017]      FIG. 3  is a cross-sectional view similar to that of  FIG. 2 , but illustrating rotation of the damper in an opposite direction to provide free wheeling rotation with no damping performance;  
         [0018]      FIG. 4  is an exploded view of another embodiment of a rotary damper in accordance with the present invention;  
         [0019]      FIG. 5  is a cross-sectional view illustrating an assembled damper of  FIG. 4  operated in a first direction to provide no damping performance; and  
         [0020]      FIG. 6  is a cross-sectional view similar to that of  FIG. 5 , but at a different rotational angle of the internal components and illustrating the damper operated in an opposite direction to that of  FIG. 5 , to provide damping performance. 
     
    
       [0021]     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use herein of “including”, “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items and equivalents thereof.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]     Referring now more specifically to the drawings and to  FIG. 1  in particular, a rotary damper  10  in accordance with the present invention is shown. Damper  10  includes a rotor  12  operable in a housing  14 , with a clutch  16  interposed between rotor  12  and housing  14 . Rotor  12 , housing  14  and clutch  16  can be made from injection molded plastic or other suitable materials.  
         [0023]     Rotor  12  includes a main body portion  18  operable within housing  14  and a shaft  20  extending outwardly of housing  14  for receiving a gear or the like, or for otherwise connecting damper  10  within a system having a component for which control is to be provided by damper  10 .  
         [0024]     Main body  18  includes a plurality of lobes  22 ,  24 ,  26  axially disposed thereon, and in the exemplary embodiment includes three lobes  22 ,  24  and  26 .  
         [0025]     However, those skilled in the art should understand that two lobes or more than three lobes also can be used. Each lobe is a wedge-shaped structure as viewed in cross-section, and includes a radially outer end  28 ,  30 ,  32 , respectively, for lobes  22 ,  24 ,  26  and a radially inner end  34 ,  36 ,  38 , respectively. Accordingly, lobes  22 ,  24 ,  26  have angular outer surfaces  40 ,  42 ,  44 , respectively, defined between the radially outer end and the radially inner end of each lobe. In the exemplary embodiment shown, each lobe  22 ,  24 ,  26  extends substantially the entire axial length of main body  18 ; however, lobes shorter than the full axial length of main body  18  can be used, and shorter lobes can be arranged in end to end arrangements along the length of body  18 .  
         [0026]     Housing  14  is a cylindrical structure having a bottom  46  and a side wall  48 . An inside surface of housing  14 , such as an inside surface of wall  48 , provides resistance to the rotation of another surface there against, such as an outer surface of clutch  16 , as will be described in more detail hereinafter.  
         [0027]     Clutch  16  includes a plurality of leaves  50 ,  52 ,  54  and in the exemplary embodiment includes three leaves  50 ,  52 ,  54 . Clutch  16  provides a separate leaf for each lobe of rotor  12 . Accordingly, clutch  16  in the exemplary embodiment includes three lobes  50 ,  52 ,  54 . Leaves  50 ,  52 ,  54  are separate one from the other and define an annular assembly in which rotor  12  operates. Leaves  50 ,  52 ,  54  are spaced one from another and define gaps  56 ,  58  and  60  between adjacent leaf pairs  50 ,  52 ;  52 ,  54 ; and  54 ,  50 . As will be described more completely hereinafter, leaves  50 ,  52 ,  54  operate between rotor  12  and housing  14  to create torque or damping resistance when rotated in one direction and minimal torque or damping resistance when rotated in an opposite direction. Accordingly, outer surfaces  62 ,  64 ,  66  of leaves  50 ,  52 ,  54  are of a contour to confront against an inner surface  68  of housing  14  when leaves  50 ,  52 ,  54  are moved there against and to provide a gap  70  when leaves  50 ,  52 ,  54  are moved away from surface  68 .  
         [0028]     Slots  72 ,  74 ,  76  are provided on the inner surfaces of leaves  50 ,  52 ,  54  respectively. Slots  72 ,  74 ,  76  are configured to cooperate with and receive lobes  22 ,  24 ,  26  to move outwardly against housing surface  68  when rotor  14  is rotated in one direction and to move inwardly away from surface  68 , creating gap  70 , when rotor  14  is rotated in an opposite direction. Accordingly, slots  72 ,  74 ,  76  have radially deeper slot ends  78 ,  80  and  82  for receiving radially outer ends  28 ,  30  and  32  of lobes  22 ,  24 ,  26 , respectively. Each slot  72 ,  74 ,  76  further includes and is defined by a lead surface  84 ,  86 ,  88 , respectively, and a trailing surface  90 ,  92 ,  94 , respectively.  
         [0029]      FIG. 2  illustrates operation of damper  10  to provide torque or damping performance. Rotor  12  is rotated in a counter-clock-wise direction as indicated by arrow  96 . Lobes  22 ,  24  and  26  withdraw partially from slots  72 ,  74 ,  76 , respectively. Outer surfaces  40 ,  42 ,  44  of lobes  22 ,  24  and  26  confront and engage trailing surfaces  90 ,  92  and  94  of leaves  50 ,  52  and  54 . Because of the angular relationships between outer surfaces  40 ,  42  and  44  and trailing surfaces  90 ,  92  and  94 , leaves  50 ,  52  and  54  are urged outwardly such that gap  70  is eliminated as outer surfaces  62 ,  64  and  66  are moved closer to or against inner surface  68  of housing  14 . Resistance to sliding movement of leaves  50 ,  52  and  54  along inner surface  68  provides torque and damping performance to a device connected to rotor shaft  20 .  
         [0030]      FIG. 3  illustrates the operation of damper  10  with rotor  12  rotated in a clockwise direction, as indicated by arrow  98 . Lobes  22 ,  24  and  26  slide into slots  72 ,  74 ,  76  respectively. As the lobes move deeper into the slots, leaves  50 ,  52 ,  54  are drawn closer to main body  18  and are drawn away from inner surface  68  of housing  14 . Gaps  56 ,  58  and  60  between adjacent leaves  50 ,  52 ,  54  become smaller, and gap  70  is formed between housing inner surface  68  and leaves  50 ,  52 ,  54 . Since no radially outward directed force is applied against leaves  50 ,  52 ,  54 , minimal resistance occurs to rotation of rotor  12 . Consequently, torque is not generated and no damping performance occurs.  
         [0031]     It should be understood that the materials used for outer surfaces  62 ,  64 ,  66  of leaves  50 ,  52 ,  54  and for inner surface  68  of housing  12  can be selected to provide the desired friction when one is moved against the other. Surface coatings can be used and/or the various components can be monolithic bodies of a desired material. Rigid base materials can be used for the leaves and/or housing, and the base material can be overmolded with a thermoplastic or rubber material having the desired friction characteristics. It may be desirable in some applications and uses of the invention to use lubricants such as graphite, silicone or the like on the frictional component surfaces to control damping performance and for improved life.  
         [0032]      FIGS. 4, 5  and  6  illustrate another embodiment of the present invention. A rotary damper  110  includes a rotor  112  and a housing  114  in which rotor  112  operates. A clutch  116  and friction disk  118  are provided to operate with rotor  112  and housing  114 .  
         [0033]     Housing  114  includes a side  120  and a bottom  122 . A cap  126  is provided for closing housing  114  and defines a hole  128  therethrough.  
         [0034]     Rotor  112  includes a rotor shaft  130  extending outwardly from housing  114  through hole  128  in cap  126 . Rotor  112  further includes a rotor plate  132  rotatable within housing  114  at a substantially fixed position axially in the housing. On an end surface  134  of plate  132  opposite shaft  130  lobes  136 ,  138 ,  140  and  142  are defined. Each lobe  136 ,  138 ,  140  and  142  is a wedge-shaped projection from surface  134  of plate  132 . Accordingly, lobes  136 ,  138 ,  140  and  142  have axially distant ends  144 ,  146 ,  148  and  150  and axially nearer ends  152 ,  154 ,  156  and  158  with respect to surface  134  of plate  132 . Lobe surfaces  160 ,  162 ,  164  and  166  are defined between the respective ends of each lobe. In the exemplary embodiment shown, four lobes  136 ,  138 ,  140 ,  142  are shown; however, more or fewer than four lobes can be used.  
         [0035]     Clutch  116  is a plate or disk  168  having a surface  170  facing friction disk  118 . On an opposite surface  172  thereof, facing rotor plate  132 , plate  168  is provided with slots  174 ,  176 ,  178  and  180 . Slots  174 ,  176 ,  178 ,  180  are configured with respect to the shape of lobes  136 ,  138 ,  140  and  142  to receive the lobes therein when rotor  112  is rotated in one direction and to allow the withdrawal or partial withdrawal of the lobes from the slots when rotor  112  is rotated in an opposite direction. Accordingly, slots  174 ,  176 ,  178  and  180  include lead surfaces  182 ,  184 ,  186  and  188 , respectively, and angular trailing surfaces  190 ,  192 ,  194  and  196 , respectively.  
         [0036]     Friction disk  118  is disposed in housing  114  between bottom  122  and clutch  116 . Friction disk  118  is of material to provide the desired friction resisting rotation of rotor  112  when axial force is applied there against by clutch  116 . One surface  198  of friction disk  118  operates against a surface  200  of housing  114 , and an opposite surface  202  operates against clutch surface  170 . Alternatively, friction disk  118  can be omitted, and clutch surface  170  can operate directly against housing surface  200  to provide damping performance. As described previously for damper  10 , surface coatings can be provided, materials selected and lubricants applied to achieve a desired damping performance.  
         [0037]      FIG. 5  illustrates operation of damper  110  in a direction indicated by arrow  204  for free wheeling, with no damping performance. As torque or rotation is applied to rotor  112 , via a moving device such as a lid or other article upon which damper  110  is installed, the angled lobes  136 ,  138 ,  140  and  142  on the rotor are urged inwardly more deeply into slots  174 ,  176 ,  178  and  180 . Clutch  116  is thereby drawn axially away from friction disk  118 , as indicated by arrow  206 , and a gap  208  is established. Gap  208  can be established between clutch  116  and friction disk  118  as shown, but also can be established between friction disk  118  and housing surface  200  if friction disk  118  is carried with clutch  116 , or is a coating on clutch  116 . Yet alternatively, if friction disk  118  is not used, gap  208  is established between clutch  116  and housing surface  200 . Generally, operation as just described establishes a position of clutch  116  which is more distant with respect to housing surface  200  such that rotor  112  is virtually free wheeling with minimal resistance.  
         [0038]      FIG. 6  illustrates operation of rotor  112  in an opposite direction, indicated by arrow  210 . As rotational force is applied to rotor  112 , the angled lobes  136 ,  138 ,  140  and  142  are withdrawn from slots  174 ,  176 ,  178  and  180 . Accordingly, outer surfaces  160 ,  162 ,  164  and  166  of lobes  136 ,  138 ,  140  and  142  are driven against trailing surfaces  190 ,  192 ,  194  and  196 . Clutch  116  is urged axially toward and against friction disk  118 , as indicated by arrow  212 . Operation as just described establishes another position of clutch  116  which is nearer to housing surface  200  such that relative rotation between clutch  116 , friction disk  118  and/or bottom  122  generates resistance to rotation of rotor  112 . The resistance can be transmitted to the object controlled via connection at rotor shaft  130 .  
         [0039]     It should be understood that various aspects of damper  10  can be used in damper  110 , and aspects of damper  110  can be used in damper  10 . For example, damper  10  can be provided with a sleeve or cylinder of friction material similar to friction plate  118  between housing surface  68  and leaf outer surfaces  62 ,  64  and  66 . Clutch  16  can then be moved against an away from the sleeve or cylinder rather than directly against surface  68 .  
         [0040]     Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.  
         [0041]     Various features of the invention are set forth in the following claims.