Abstract:
A damping assembly for a pivoting stowage bin includes a rotary hydraulic damper that is mounted on the pivot axis of the stowage bin. The rotary hydraulic damper includes a damper body that receives a rotor having at least one vane moved through contained hydraulic fluid. Preferably, an exterior bearing surface on the damper precludes the active damping elements from radial loads, while a distributed attachment of the rotor to the pivoting bin enables reduced torque loads. The damper can include an integrated flow-control valve for controlling the opening rate of the pivoting bin as well as an integrated mechanical stop for the bin.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119 based on U.S. Ser. No. 61/615,620, filed Mar. 26, 2012, and entitled: Rotary Hydraulic Damper for Pivoting Stowage Bin, the entire contents being herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to the field of damping systems and more specifically to a rotary hydraulic damper for use with a pivoting stowage bin, such as those commonly used in commercial aircraft. More specifically, at least one rotary hydraulic damper can be mounted along the pivot axis of the pivoting stowage bin such that torque loads can be distributed, thereby permitting manufacture using lower cost materials. The rotary hydraulic damper can further be mounted to the pivoting stowage bin such that radial loads are not imparted to the moving elements of the damper. According to one version, the rotary hydraulic damper can include at least one flow control valve that standardizes the opening rate of the bin irrespective of the weight put into the stowage bin, wherein the damper can further include an integrated mechanical stop as well as means for adjusting the open position of the stowage bin. 
     BACKGROUND AND RELEVANT ART 
     Stowage bins, such as those provided on commercial aircraft, typically incorporate a pivot assembly at the axis of rotation of the bin bucket. This assembly supports the bin load and allows the bucket to rotate about the axis of rotation in relation to a stationary bin housing. 
     It is preferred in such assemblies to be able to effectively control the opening rate of the stowage bin. Typical rotary bin dampers are relatively expensive in terms of cost and manufacture, relying upon relatively complex and largely metallic assemblies including a center splined shaft that typically receives both torque and radial loads. 
     In addition, these rotary bin dampers also typically utilize single fixed orifices, which means that the stowage bin opens inconsistently based on the weight that is actually contained within the bin. That is, the stowage bin opens slowly when the bin is empty as compared to when the bin is full. 
     It is therefore a general desire in the field to improve the manufacturability of the above-noted damping assemblies as well as to decrease the overall complexity thereof in order to reduce cost, while not sacrificing reliability. 
     SUMMARY 
     Therefore and according to a first aspect there is described a damping assembly for a pivoting stowage bin, the assembly comprising a rotary hydraulic damper that is mounted along the pivot axis of the stowage bin, the stowage bin including a bin bucket which is pivotally attached to a stationary bin frame. The rotary hydraulic damper is mounted at one end of the pivot axis and includes a stator and a rotor engaged within the stator. The rotor is mounted for rotation to the pivoting bin bucket about the pivot axis of the bin assembly and the stator is mounted to the bin frame. 
     In one version, the rotor can include a plurality of keys that are engaged with corresponding keyways formed in a mounting plate of the pivoting bin bucket. The keys are radially positioned relative to the center axis of the damper assembly, which is substantially aligned with the pivot axis of the bin assembly. In this manner, torque loads are distributed away from the center of the damper and therefore lower cost materials, such as moldable plastics, can be utilized for manufacture. In accordance with one version, at least one elastomeric spacer can be provided between the keyed connection of the rotor and the pivoting bucket so as to more evenly distribute the load to the keys, and provide manufacturing gap alignment to prevent rattling from vibratory effects. 
     In one version, the damper assembly includes at least one flow control valve used for controlling the opening rate of the pivoting bin bucket. The at least one valve can be positioned within the vanes of the rotor, the stator or within a central shaft portion of the damper. In one version, the valve is spring loaded and positioned within an annular cavity to affect the size of orifices between adjacent pressure chambers formed by the rotor and stator vanes of the damper based on the amount of force so as to provide substantially constant angular velocity of the pivoting bin irrespective of the load within the bin. 
     According to another version, the hydraulic damper is mounted to the bin such that an annular exterior bearing surface of the damper body accepts substantially all radial loads imparted to the assembly wherein the moving components of the rotary hydraulic damper receives only torque loads. 
     According to yet another version, the herein described damper assembly can further include at least one integrated feature for creating a mechanical stop position for the bin when fully opened. In one version, the damper body includes at least one stop lug that is engaged with a slotted portion of a mounting bracket of the pivoting bin. Additionally, means can be provided for adjusting the stop position, for example, relative to adjacent bin assemblies. According to one version, a plurality of mounting holes on the mounting bracket can be slotted to provide adjustability. 
     The rotary hydraulic damper according to one version can include a damper body that is stationarily attached to the bin housing and a rotor mounted for rotation within said damper body, each of the damper body and the rotor including at least one vane forming a plurality of variable interior fluidic chambers. The rotor is attached to the pivoting bucket and is caused to move rotationally about the pivot axis when the bin is opened and closed. According to one version, the rotor can be attached to the bucket by a keyed arrangement. Rotational movement of the rotor within the damper body causes movement of contained hydraulic fluid between the variable fluidic chambers. 
     The flow control valve according to one version can include an axial valve member that is disposed within a manifold disposed within a center axis of the damper, wherein a bias spring can be disposed in operative association with the axial valve member. The manifold defines a subchamber between high and low pressure sides of the damper. In brief, the flow control valve provides constant angular velocity of the rotor in response to the application of a load from the pivoting bucket by metering the flow of hydraulic fluid from a first chamber of the damper on a high pressure side to a second chamber defined on a low pressure side thereof. 
     According to another aspect, there is described a hydraulic rotary damping assembly for use in a pivoting bin, the bin including a bucket pivotally attached to a stationary housing, the damping assembly comprising: 
     a hydraulic damper disposed along the pivot axis of the pivoting bin; and 
     a weight compensated valve disposed within the hydraulic damper for controlling the opening rate of the bucket. 
     In terms of advantages, a traditional hydraulic rotary damper typically has a splined axial input shaft in the center of the damper to accept the transmitted torque. Because the torque is applied at the center of the damper, expensive metal components are required in order to withstand the stresses from the torque at the center of the damper. By moving the transmitted torque away from the center of the damper according to the present assembly, the stresses are effectively reduced, and therefore other lightweight and less expensive materials, such as plastic, can be suitably utilized to transmit the torque. 
     In addition, traditional hydraulic rotary dampers also typically employ bearings around the splined input shaft to support the radial loads from the stowage bin and its contents. As a consequence, the moving vanes of this damper design would therefore encounter both torque and radial loads. By utilizing the exterior surface of the damper body as the bearing surface for any radial loads, the moving damper vanes will only encounter torque, thereby extending the overall life of the damper and the pivoting bin assembly. The foregoing also keeps the thickness of the damper to a minimum since long internal bearings are not required. 
     Still further, the incorporation of a positive mechanical stop on the outside of the damper body minimizes the loads on the stop due to its distance away from the axis of rotation. The positioning of this stop advantageously allows the use of lower cost materials, such as plastic, and further allows the bin designer to eliminate the manufacture of separate stop elements in the assembly. 
     Still further, a traditional hydraulic damper utilizes a single orifice to provide the needed damping force from the fluid. In these types of applications, the bin will open slowly when empty and much faster when the bin is fully weighted. By incorporating a flow control valve within the damper in accordance with the herein described assembly, the opening time of the stowage bin can be effectively controlled and standardized irrespective of the amount of loading therein. 
     These and other features and advantages will become readily apparent from the following Detailed Description, which should be read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a prior art pivoting stowage bin; 
         FIG. 2  is a rear perspective view of a rotary hydraulic damper made in accordance with an exemplary embodiment; 
         FIG. 3  is a front perspective view of the rotary hydraulic damper of  FIG. 2 ; 
         FIG. 4  is an exploded assembly view of the rotary hydraulic damper of  FIGS. 2 and 3 , as shown in rear perspective; 
         FIG. 5  is an exploded assembly view of the rotary hydraulic damper of  FIGS. 2-4 , as shown in front perspective; 
         FIG. 6  depicts an exploded mounting arrangement of the rotary hydraulic damper of  FIGS. 2-5 , including a mounting configuration for a pivoting bin assembly, this depiction being shown in side by side front and rear perspective views; 
         FIGS. 7 and 8  are perspective views of the mounting arrangement of the rotary hydraulic damper of  FIG. 6 , illustrating an integrated mechanical stop feature; 
         FIG. 9  is an enlarged side elevational view of a manifold used in the rotary hydraulic damper of  FIGS. 2-8 ; 
         FIG. 10  is a sectioned side view of the rotary hydraulic damper of  FIGS. 2-9  including an integrated flow control valve in accordance with one exemplary embodiment; and 
         FIG. 11  is an enlarged view of a portion of the flow control valve of  FIG. 10  as operatively used. 
     
    
    
     DETAILED DESCRIPTION 
     The following relates to an exemplary embodiment of a rotary hydraulic damper assembly used in conjunction with a pivoting stowage bin, such as those typically found on commercial aircraft. It will be readily apparent, however, that numerous other variations and modifications are possible that generally embody the inventive concepts described herein. Moreover, it will also be readily apparent that these concepts may also be similarly applied to other related fields of endeavor. During the course of discussion, certain terms such as “distal”, “proximal”, “inner”, “outer”, “lateral”, “internal” and “external”, among others are used for purposes of providing a suitable frame of reference in regard to the accompanying drawings. These terms are not intended to be overly limiting of the inventive concepts described herein, however, unless otherwise specifically indicated. 
     In addition, the accompanying drawings are intended to convey the inventive concepts more readily, but the drawings themselves are not drawn necessarily to scale and should not be relied upon in that regard. 
     For purposes of background, a prior art stowage bin is shown according to  FIG. 1  to which the rotary hydraulic damper described herein can be applied. The stowage bin  20  includes a bin bucket  24 , which is hingably connected at a pair of opposing lateral ends to a stationary bin housing  28 . Other suitable pivoting stowage bin assemblies having different bin bucket configurations are described by way of example, in U.S. Patent Application Publication No. 2011/0253837A1, the relevant contents of which are herein incorporated by reference. The bin housing  28  is fixedly attached to the aircraft frame at each lateral end in order to form respective bin walls wherein the lateral walls of the bin bucket  24  are pivotally attached through a mounting arrangement to respective parallel walls of the stationary housing, therein providing the pivot location for the stowage bin  20 . When assembled, the interior of the bin bucket  24  and bin housing  28  combine to define an enclosure  32  wherein the bin bucket further includes an exterior latch  31  to enable the stowage bin  20  to be selectively opened and closed by a user. In use, the bin bucket  24  is released from a latched position (not shown in this view) by the latch  31  and caused to pivot through an attached mounting arrangement relative to the stationary housing  28  to an open position, as shown, presenting the enclosure  32  for either placement or removing of luggage (not shown). Additional details of exemplary stowage bins are provided in the above cross-referenced publication. 
     According to the present exemplary embodiment and referring to  FIGS. 2 and 3 , a pair of rotary hydraulic dampers  40  are attached to each end of a stowage bin, such as the one shown by way of example according to  FIG. 1 , wherein each of the dampers  40  are disposed along the pivot axis of the stowage bin in a mounting arrangement between the bin bucket  24 ,  FIG. 1 , and the stationary bin housing  28 ,  FIG. 1 . For purposes of this discussion, only a single rotary hydraulic damper  40  is described and shown herein and in which the remaining damper is essentially a mirror image thereof in terms of its structure, functionality and mounting arrangement. It should be noted, however, that in an alternative embodiment, a single rotary hinge damper could be provided in lieu of separate rotary hydraulic dampers at each opposing lateral end of the stowage bin  20 . 
     The rotary hydraulic damper  40  according to this embodiment and shown in assembled form in  FIGS. 2 and 3  is defined by a distal end  42  that is attachable to the stationary bin housing  28 ,  FIG. 1 , using a mounting flange  46  and an opposing proximal end  48  that is separately connectable to the pivoting bin bucket  24 ,  FIG. 1 , using a set of circumferentially spaced keys  52 , as described in greater detail in a later section. The relative positioning of the damper  40  according to this embodiment is based upon a stowage bin design that includes a pivoting bin  24 ,  FIG. 1 , forming the interior member relative to an exterior bin housing  28 ,  FIG. 1 . It will be readily apparent that the relative distal and proximal ends  42 ,  48  of the hydraulic rotary damper  40  can be reversed, for example, depending on the structure of the pivoting stowage bin for purposes of mounting. 
     As shown in  FIGS. 4 and 5 , the rotary hydraulic damper  40  is essentially a two-part structure comprising a damper body  56  having an interior cavity that is sized to receive a rotor  60  that is mounted for rotation therein. The damper body  56  according to this embodiment includes the mounting flange  46  at a distal end or side thereof, wherein the mounting flange includes a plurality of circumferentially spaced slots  64  disposed along an outer radial portion  68  thereof, as well as a center opening  72 . An open-ended cylindrical sleeve portion  76  extending axially from a rear side of the mounting flange  46  defines the interior cavity of the damper body  56 , which is hollow with the exception of a pair of diametrically opposed and substantially wedge-shaped vanes  80 , each tapering inwardly from the interior diameter of the sleeve portion  76  to the center opening  72  of the mounting flange  46 . The exterior surface  84  of the sleeve portion  76  of the damper body  56  is substantially cylindrical with the exception of a stop lug  88  formed as an axial extension of the outer radial portion  68  of the mounting flange  46  and in which the outer radial portion extends radially outward from the exterior diameter of the cylindrical sleeve portion  76 . 
     Still referring to  FIGS. 4 and 5 , the rotor  60  according to this embodiment is sized for engagement within the open-ended cylindrical sleeve portion  76  of the damper body  56 . The rear or proximal end of the rotor  60  is defined by a circular plate  90  having the set of circumferentially disposed keys  52  formed thereon, as well as having a center opening  94 . Each of the keys  52  are substantially wedge-shaped and are disposed at an intermediate radius from a center opening  94 . The front side or end of the rotor  60  includes an axially extending cored center section  98  as well as a pair of radially extending vanes  102 , the vanes tapering outwardly from the cored center section  98  to an outer radius that is substantially equal to that of the rear circular plate  90 . The rotor  60  is inserted into the open-ended sleeve portion  76  of the damper body  56  such that the cored center section  98  extends between the diametrically opposed vanes  80  of the damper body  56  and in which the vanes  102  of the rotor  60  are fitted between the vanes  80  of the damper body  56 , therein defining a set of variably sized hydraulic chambers. This set of chambers varies in number between two and four hydraulic chambers, depending on the position of the rotor vanes  102 . It will be readily apparent that the overall number and shapes of the vanes  80 ,  102  utilized can be suitably configured as needed. The cored center section  98  further includes a corresponding number of small lateral openings or orifices defined therein, each axially and radially spaced apart. According to this specific embodiment, two ( 2 ) pairs of openings are defined, including a pair of first openings or orifices  108  and a spaced pair of second openings  112 . Each of the defined orifices  108 ,  112  is configured in relation to a defined interior hydraulic chamber of the damper  40 . In terms of the present drawings, only single openings of each pair  108 ,  112  are depicted in  FIGS. 4 and 5 . When assembled, a pair of seal members  118 ,  113 , such as elastomeric O-rings, provide sealing interface between respective outer and inner interior flange surfaces of the rotor  60  and damper body  56 , as shown most clearly in an assembled condition in  FIG. 10 . 
     According to this embodiment, a manifold  116  is sized to be slidingly fitted within the cored center section  98  of the assembled rotor  60 . As shown in  FIG. 9 , the manifold  116  is defined by a substantially cylindrical body member having a plurality of grooves  120 ,  122  that receive sealing members  119 ,  121 ,  FIGS. 4, 5 , as well as a set of lateral openings  123 ,  125  disposed within adjacent grooves  129 ,  131 , the openings being aligned with the openings  108 ,  110  of the damper  40  when the rotor is rotated within the damper body  56 . A valve element  124  is axially disposed within the subchamber that is defined by the interior of the manifold along with a bias spring  128  operative associated with the valve element as described in a later section. The manifold  116  is fixedly maintained by a retainer member  130  that is mounted through the center opening  72  of the damper body  56  from the distal side. The retainer member  130  includes a threaded distal portion  134  that is configured and sized to engage an internally threaded end  117  of the manifold  116 , thereby retaining the components of the herein described damper assembly. 
     The distal side of the herein described damper body  56  further includes a pair of small openings  138  extending into the defined cavities and permitting the inclusion of fill plugs  140  to enable a quantity of suitable hydraulic fluid (not shown) to be added to the defined interior hydraulic chambers following assembly of the damper  40 . 
     Referring to  FIG. 6  and in terms of mounting the herein described rotary hydraulic damper  40  to the pivoting bin, aligned openings (not shown) are provided in each of the bin bucket  24 ,  FIG. 1 , and the bin housing  28 ,  FIG. 1 , along the pivot axis. A pivoting mounting plate  150  is fixedly attached to the bin bucket  24 ,  FIG. 1 . The mounting plate  150  according to this embodiment includes a rear mounting bracket  154  having a plurality of circumferentially spaced mounting holes  158  along an outer radial portion  162 , and an axially extending and open-ended receiving portion  166  which is substantially cylindrical in configuration and defined by an interior diameter that is sized to correspondingly mate with the exterior diameter of the sleeve portion  76  of the damper body  56 . The mounting plate  150  further includes a set of features configured to engage the keys  52  on the proximal side of the rotor  60 . According to this embodiment, three (3) keys  155  are utilized, each of the keys being substantially wedge-shaped and symmetrically disposed about at an intermediate radial distance from the center of the bracket  154  and wherein a spacer  170  is introduced into the receiving portion  166  thereof. In this embodiment, the spacer  170  and corresponding keys  155  on the front side of the mounting bracket  150  combine to form a set of keyways that engage the keys  52  of the rotor  60 . The spacer  170  is preferably elastomeric in order to take up manufacturing tolerances and also provide manufacturing gap alignment and minimize rattling or vibratory effects on the pivoting bin. 
     The mounting flange  46  of the damper body  56  is fixedly attached to the bin housing  28 ,  FIG. 1 , using fasteners (not shown) secured through the mounting slots  64  formed on the outer radial portion  68  and the bin housing  28 ,  FIG. 1 , respectively. When assembled, the damper body  56  extends through an opening (not shown) of the stationary bin housing  28 ,  FIG. 1 , such that the outer diameter of the damper body is secured within the inner diameter of the opening. 
     As the pivoting bin bucket  24 ,  FIG. 1 , rotates, the mounting plate engagement with the keys  52  causes the rotor  60  to rotate with the bin bucket  24 ,  FIG. 1 , and within the interior of the damper body  56  while the damper body remains stationarily mounted to the bin housing  28 ,  FIG. 1 . 
     Referring to  FIGS. 7 and 8 , the receiving portion  162  of the pivoting mounting plate  150  further includes a slot  174  that is cut axially from an outer surface over a circumferential section thereof. The purpose of this slot  174  is to provide a mechanical stop for the bin bucket  24 . That is and as the pivoting bin  24 ,  FIG. 1 , is pivoted on opening, the mounting plate and attached rotor are caused to rotate between the positions shown in  FIGS. 7 and 8  until the stop lug  88  encounters the end of the slot  174 . 
     Referring to  FIGS. 9-11 , discussion is herein made of the flow control (weight compensating) valve used in accordance with this exemplary embodiment. 
     As previously noted, the central cored section  98  of the herein described rotary hydraulic damper  40  includes a first set of holes  108  and an adjacent second set of holes  112 , each spaced to provide high pressure and low pressure regions in terms of movement of contained hydraulic fluid through the defined hydraulic chambers within the damper. According to this embodiment, and as the bin bucket  24 ,  FIG. 1 , is opened, the bucket is caused to pivot about the pivot axis, thereby causing the rotor  60  to rotate based on the keyed connection to the pivoting bin mounting plate  150 . Relative movement of the rotor vanes  102  within the damper  40  therefore causes contained hydraulic fluid to be moved under high pressure through the inlet holes  108  of the cored section  98  towards the opposing low pressure regions or chambers thereof and into the subchamber defined by the interior of the manifold  116 , in which fluid is caused to enter the subchamber as fluid flows through holes  108  and into holes  123  via the exterior groove  129  along a defined first fluid flow path. 
     The interposed valve element  124  is biased by the axially disposed spring  128  against that of the moving fluid in regard to the inlet holes  123 . As the hydraulic fluid pushes against the force of the biased spring  128  based on a pressure gradient developed as the fluid flows through an intermediate orifice  126  in the valve element  124 , the valve element  124  is moved towards the outlet orifices  125 , and partially cuts off fluid flow through the outlet orifices  125 , substantially creating a constant rate of fluid flow irrespective of the force applied due to the compensating effect of the spring  128 . Details as to the theory of this specific valve are provided in U.S. Pat. No. 7,967,116, the entire contents of which are herein incorporated by reference. During opening of the bin bucket  24  and once the hydraulic fluid flows through the outlet orifices  125 , this fluid flows into the groove  131  of the manifold  116  and then exits through the holes  112  into the low pressure region created by the rotor vanes  102  and stator vanes  80 . 
     The preceding description relates to a central axial positioning of the flow control valve for purposes of this exemplary embodiment. However, there are alternative configurations that could easily be realized. For example, separate flow control valves employing the preceding principles could be positioned in relation to each of the rotor vanes or stator vanes. In addition, modifications can be optionally included due to the spring loaded nature of the herein-described flow control valve and the accessibility of the manifold  116 . For example, an adjustment feature (not shown) can be added so adjustments can be made to the preload of the spring  128  to change the flow rate of fluid through the valve, thereby changing the opening rate of the bin bucket  24 . In addition, adjustments can be made mechanically to the herein described system regarding the return path of fluid, for example, allowing additional fluid to flow to make closing the bin bucket easier. When closing the bin bucket  24 , the rotor  60  will rotate in the opposite direction causing fluid within the damper to flow in the direct opposite direction. Additional fluid flow can be created through the use of a check valve, which opens when closing the bin. This additional fluid flow causes the damper to create less resistance to movement, thus making it easier to close the bin bucket  24 . An embodiment of this valve is shown in  FIG. 11 . As fluid flows into hole  112  and into the groove  131  of the manifold  116 , fluid can flow through the annular area  132  and force the sealing member  121  to move away from the annular area  132 . Cylindrical sections  133 ,  FIG. 9 , cut away from the wall in the manifold  116  prevent the sealing member  121  from sealing against the wall and thus allows fluid to flow under the sealing member  121 , through the cylindrical sections  133  into groove  129  and then exiting through the openings  108  formed in the damper and into the low pressure region created by the rotor vanes  102  and stator vanes  80 . 
     Additional details concerning various linear versions of the preceding valve structure are provided in previously incorporated U.S. Pat. No. 7,967,116. 
     By attaching the rotary hydraulic damper in the manner described herein and along the pivot axis of the stowage bin  20 ,  FIG. 1 , such as by distributing the torque loads away by eliminating the traditional splined shaft common to most dampers, the major components of the damper can be suitably manufactured from lightweight and more inexpensive materials, such as moldable plastics. As a result, manufacturing costs are significantly reduced. In addition, the removal of a splined shaft from the center of the herein described damper permits the inclusion of the load compensating valve without significant impact to the footprint. As a result, additional functionality is provided to the herein described assembly. 
     PARTS LIST FOR FIGS.  1 - 11   
     
         
           20  stowage bin 
           24  bin bucket 
           28  bin housing 
           31  latch, exterior 
           32  enclosure 
           40  rotary hydraulic damper 
           42  distal end, damper 
           46  mounting flange, damper 
           48  proximal end, damper 
           52  keys, circumferentially disposed 
           56  damper body 
           60  rotor 
           64  slots 
           68  outer radial portion, body 
           72  center opening, body 
           76  open-ended sleeve portion 
           80  vanes, damper body 
           84  exterior surface, sleeve portion 
           88  stop lug 
           90  circular plate, rotor 
           94  center opening, rotor 
           98  cored center section, rotor 
           102  vanes, rotor 
           108  opening or orifice 
           112  opening or orifice 
           113  sealing member 
           116  manifold 
           117  threaded end, manifold 
           118  seal member 
           119  sealing member 
           120  groove 
           121  sealing member 
           122  groove 
           123  lateral opening 
           124  valve element 
           125  lateral opening 
           126  intermediate orifice 
           128  bias spring 
           129  groove 
           130  retainer member 
           131  groove 
           132  annular area 
           133  cylindrical sections 
           134  distal threaded portion, retainer member 
           135  sealing member 
           138  openings, fill 
           140  fill plugs 
           150  mounting plate, pivoting bin bucket 
           154  rear mounting bracket 
           155  keys 
           158  mounting holes 
           162  outer radial portion 
           166  axial extending rear portion 
           170  spacer 
           174  slot 
       
    
     Although exemplary embodiments have been described herein, it will be readily apparent that there are numerous variations and modifications that could be further employed in the furtherance of the inventive concepts described herein and according to the following claims.