Abstract:
A vibration isolator includes a base plate having a first attachment feature that enables attachment of the isolator to a first surface, the isolator further including a second attachment feature permitting attachment to a second surface. A spring section disposed between the base plate and the second attachment feature has a first radiused section and a second radiused section, each of the first and second radiused sections being formed in opposing directions on a continuous spring portion intermediate to the base plate and second attachment feature and in which the spring section provides noise attenuation and isolation between the first and second surfaces.

Description:
TECHNICAL FIELD 
     This application generally relates to the field of noise and vibration isolation and more specifically to a vibratory isolator for use in numerous structural applications, such as within the cabin of an aircraft for attenuation of noise and vibration. 
     BACKGROUND 
     It is necessary to be able to isolate vibratory and noise effects occurring between various structural components, for example in aircraft applications such as between the aircraft frame and trim panel within the interior of an aircraft fuselage. To that end, a number of current isolators that have been developed for use are typically elastomeric, such as those manufactured by Lord Corporation and Barry Controls. Other isolator versions, such as those developed by the Boeing Company, include a metallic isolator consisting of separate Belleville washers that are placed in back to back relation. 
     In order to be effective, trim panel isolators require low damping, as well as a soft spring element. To that end, there is a general need in the field to improve the overall manufacturability and effectiveness of these components. 
     SUMMARY 
     According to one aspect, there is provided a vibration isolator comprising a base plate having a first attachment feature configured to enable said isolator to be secured to a first surface, said isolator further including a second attachment feature that is configured for securing said isolator to a second surface. A spring section interconnects the first and second attachment features and includes a pair of spring legs and a planar section that supports the second attachment feature, each of the spring legs having a first radiused section and a second radiused section oppositely disposed on opposing ends of an interconnecting axial section. 
     In one version, the first attachment feature includes at least one mounting hole provided on the base plate of the isolator, and the second attachment feature is a post supported by the planar section of the spring section that supports a fastener and in another includes at least one mounting hole provided on the planar section. According to one version, the entire isolator is formed from a unitary component, such as metal, plastic, corrosion resistant steel, carbon fiber or other suitable material. 
     At least one elastomeric pad can also be optionally provided between at least one of the base plate and spring section and the second attachment feature and the spring section. Effectively, the herein described isolator decouples the first surface, such as an aircraft frame, from a second surface, such as a trim panel, thereby resulting in noise attenuation. 
     According to another version, there is provided a vibration isolator for an aircraft, said isolator comprising a base plate having a first attachment feature adapted for attaching said isolator to an aircraft frame, the assembly further comprising a second attachment feature for attaching said isolator to a trim panel of the aircraft, said isolator being disposed between the frame and said trim panel, and a spring section disposed between the base plate and said second attachment feature, the spring section including a first radiused section and a second radiused section, each radiused section being oppositely disposed on opposing ends of a continuous section intermediate to said first and second attachment features and wherein the second attachment feature is supported by a planar surface formed at one end of the spring section. 
     According to at least one version, the isolator is made from a unitary component, each of the base plate, second attachment feature and spring section being integral thereto and in which the isolator is further manufactured from a single material such as metal, plastic, corrosion resistant steel, carbon fiber or other suitable material. 
     In one version, the second attachment feature comprises a post that includes a center opening that is sized to receive a fastener securing the isolator to the trim panel. According to another version, the second attachment feature includes at least one mounting hole formed in the planar surface of the spring section. 
     At least one elastomeric pad can be optionally disposed between one of the base plate and the second attachment feature and the spring section of the isolator. 
     In one version, the spring section of the isolator includes at least one axial portion spanning the first and second radiused sections, the axial portion being substantially parallel to the planar surface and the base plate. 
     According to yet another version, there is provided a method for manufacturing vibratory isolator, the method comprising the steps of: providing a base plate having a first attachment feature capable of securing said isolator to a first surface; providing a second attachment feature capable of securing said isolator to a second surface; and providing a spring section intermediate to said first and second attachment features, said spring section including a first radiused section and a second radiused section relative to a spanning axial portion and a planar portion that supports the second attachment feature. 
     According to one version, each of the base plate, second attachment feature and spring section can be integrally formed as an unitary component. To that end, the entire isolator can be made from a single material such as metal, plastic, corrosion resistant steel, aluminum or carbon fibers, among others. 
     At least one elastomeric element can be provide between at least one of the base plate and the spring section and between the second attachment feature and the spring section to vary the spring rate and damping characteristics of the isolator. 
     In at least one version, the spring section includes a pair of spaced spring legs, the spring legs including the first and second radiused sections and the axial interconnecting portion. Preferably, each of the base plate, the planar section and the axial portions are substantially parallel to one another. 
     Advantageously and using the herein described isolator, vibratory forces can be effectively isolated and noise effects substantially eliminated or reduced. 
     The isolator, being preferably made as a unitary component, permits easy assembly to respective components. Moreover, the herein described isolator is also easier to manufacture than earlier versions designed for this purpose. 
     The design of the herein described isolator further permits a soft spring rate in three orthogonal directions and is therefore highly effective in terms of vibratory isolation. 
     The inclusion of at least one optionally provided elastomeric pad disposed on the isolator, for example between the, vibratory component and the base thereof, further softly snubs overloading conditions. 
     Because the isolator main section is not elastomeric, it will provide consistent isolation over a wide temperature range. For example, the herein described isolator will not be subject to hardening at cold temperature. 
     These and other features and advantages will be 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 dual radius vibration isolator in accordance with an exemplary embodiment; 
         FIG. 2  is a side elevational view of the vibration isolator of  FIG. 1 ; 
         FIG. 3  is a front facing view of the vibration isolator of  FIGS. 1 and 2 ; 
         FIG. 4  is a top plan view of the vibration isolator of  FIGS. 1-3 ; 
         FIG. 5  is a perspective view of a dual radius vibration isolator in accordance with another exemplary embodiment; and 
         FIG. 6  is a perspective view of a vibration isolator made in accordance with yet another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following relates to certain exemplary embodiments of a dual radius vibration/noise isolator as described for use in aircraft applications and more specifically for use between the frame and the trim panel within the interior of a commercial aircraft vehicle. It will be readily apparent from the discussion that follows that this isolator concept can be similarly utilized in other assemblies, such as automotive and industrial among others, and in which effective vibration and noise attenuation is needed or desired. Throughout the course of the discussion that follows, a number of terms are frequently used in order to provide a suitable frame of reference with regard to the accompanying drawings. It should be noted that these terms, which include “upper”, “lower”, “inner”, “outer”, “above”, “below”, “top” and “bottom”, among others, are not intended to be restrictive and to overly narrow the scope of the inventive aspects, as discussed herein and further recited in the claims that directly follow this discussion, unless otherwise and as specifically noted herein to the contrary. 
     It should further be noted that the accompanying drawings are not necessarily presented to scale and therefore no narrowing interpretation should be made in terms of dimensions that have been depicted. 
     As used in this specification and the appended claims, the singular forms “a”, “an” and “the” are intended to further include plural referants, unless the context clearly dictates otherwise. 
     The term “about” or “approximately”, as used in connection with any numerical value throughout the description and the claims denotes an interval of accuracy, familiar and acceptable to a person skilled in the art. The interval governing this term is preferably ±20%. 
     Referring to  FIGS. 1-4 , there is shown a perspective view of a vibration isolator that is made in accordance with a first exemplary embodiment. According to this embodiment, the vibration isolator  100  is made as a single unitary component that is manufactured or formed from a material such as aluminum, steel, plastic, CRES (corrosion resistant steel) and/or carbon fiber, although other suitable structural materials could also be utilized. In other versions, the isolator can alternatively be constructed from separate components that are secured together to form an assemblage. 
     A defined planar base or base plate  108  includes a lateral tab portion  112  at one end, the tab portion including a first attachment hole or opening  116 . A corresponding second opening or hole  118  is provided on an opposite side of the base plate  108  and in alignment with the first attachment hole  116  wherein the first and second attachment holes  116 ,  118  combine to define a first attachment feature for purposes of securing the isolator  100  to the interior of an aircraft frame (not shown). Though two attachment holes  116 ,  118  are provided in this exemplary embodiment, it will be readily apparent that this number can be suitably varied. 
     According to this exemplary embodiment, a second attachment feature is further provided in the form of a hollow post  120  that extends upwardly from the upper surface  134  of a planar section  138  of an isolation component  128  that is disposed above and parallel to the base plate  108 . According to this embodiment and due to the integrality of the isolator  100 , the post  120  is integrated into the planar section  138 . As previously noted, the post  120  could alternatively be supported by the planar section  138  as a separate component using means such as adhesives, heat sealing, welding and other mechanical securing means. According to this embodiment, the post  120  is defined by a substantially cylindrical configuration that includes a center opening  124  sized and configured to receive a fastener (not shown) of an aircraft trim panel (not shown). According to one version, the center opening  124  of the hollow post  120  can include internal threads (not shown) for engaging a threaded fastener (not shown). Alternatively and as shown in  FIG. 5 , a mounting hole  126  can be provided in the planar section  138  to serve as an attachment feature for securing the isolator to the trim panel (not shown). 
     Intermediate to the base plate  108  and the hollow post  120  is the isolator component  128 ,  FIG. 2 , which according to this exemplary embodiment is defined by a spring portion  130 ,  FIG. 2 , comprising a pair of curved spring legs  142 . Each of the curved spring legs  142  are defined by a pair of radiused sections; namely, a first radiused section  146  that curls upwardly relative to the planar base  108  along a  180  degree path extending to one end of an axial section  154  and a second radiused section  150  that extends between the opposing end of the axial section  154  and curls downwardly to a lateral edge of the planar section  138  supporting the hollow post  120 . Each of the axial sections  154  are parallel to one another, wherein the planar section  138  is disposed substantially intermediate to the base  108  and each axial portion  154 . The planar section  138  spans substantially over the length of each axial portion  154 , as well as the entire width of the base plate  108 . As a result, each of the spring legs  142  of the isolator  100  form a curvi-linear configuration in which the planar section  138  is sandwiched between the base plate  108  and the top of each spring leg  142 , as best seen in  FIGS. 1 and 2 . In this configuration and as shown most clearly in  FIG. 3 , the top of the post  120  extends slightly above the top of the spring legs  142 . 
     In terms of the operation of the isolator  100  and still referring to  FIGS. 1-4 , the base plate  108  is mounted to the interior of the aircraft frame (not shown) while the hollow post  120  is arranged relative to a mounting hole of a trim panel (not shown) such that the isolator is disposed therebetween. As vibrational loads are imparted to the aircraft frame (not shown), the isolation component  128  and more particularly the spring legs  142  through flexion thereof store energy to provide isolation, and as a result reduce noise transmission to the interior of the aircraft cabin. Moreover and due to the substantially curvi-linear configuration of the spring legs  142 , and more particularly the opposing first and second radiused sections  146 ,  150  and the axial sections  154 , deflection can effectively be provided in three (3) orthogonal directions; that is, in a direction of the hollow post  120  as well as the planar directions of the spring legs  142 . 
     Referring to  FIG. 6 , there is shown an alternative embodiment of a vibration isolator  200 . Similar parts are herein labeled with the same reference numerals for the sake of clarity. As in the preceding version, the vibration isolator  200  includes a planar base or base plate  108  having attachment holes  116 ,  118  at opposing sides that provide a first attachment feature for purposes of enabling attachment of the isolator to the interior of an aircraft frame (not shown), as well as a hollow substantially cylindrical post  120  having a center opening  124  that receives a fastener (not shown) of a trim panel of the aircraft. As previously noted, alternative attachment features can be provided in lieu of the post  120 , such as a mounting hole (not shown) as previously described. An isolation component  128  disposed between the post  120  and the base plate  108  includes a pair of spring legs  142  in parallel relation, each of the spring legs further comprising opposing first and second radiused sections  146 ,  150  that are separated by an axial section  154  and a planar section  138 , which is substantially parallel to the axial section  154  and base plate  108 , the planar section having an upper surface  134  upon which the post  120  is integrally disposed. The herein described isolator  200 , including each of the foregoing features according to this embodiment, is formed as a single component and a single material as previously described although separate attachment, for example, of the isolation component  128  to the base plate  108  or the post to the isolation component are suitable and alternative design constructions. 
     According to this exemplary embodiment, at least one elastomeric pad element  224  can be added to the isolator  200  in the event additional damping or obtaining a higher spring rate is required. As shown in  FIG. 6 , a pair of optional elastomeric pad elements  224  are provided in which one of the pad elements is provided in relation to the hollow post  120  and another pad element  224  is disposed between the planar section  138  and the base plate  108 . The pad elements  224  can be secured based on frictional fit or using adhesives, fasteners and/or other conventional techniques. 
     As noted, the herein described vibration isolators  100 ,  200  have been described in connection with an aircraft. However, various other suitable structural applications that require low stiffness and low damping, such as those used on buses and trains, can also similarly utilize this design. 
     PARTS LIST FOR FIGS.  1 - 6   
     
         
           100  isolator 
           108  planar base or base plate 
           112  lateral tab portion 
           116  first attachment hole or opening 
           118  second attachment hole or opening 
           120  post, hollow 
           124  center opening 
           126  mounting hole 
           128  isolation component 
           130  spring portion 
           134  upper surface 
           138  planar section 
           142  spring legs 
           146  first radiused sections 
           150  second radiused sections 
           154  axial sections 
           200  isolator 
           224  elastomeric pads 
       
    
     It will be readily apparent that various modifications and variations can be made in regard to the herein described isolator to those of sufficient skill and as recited in accordance with the following claims.