Abstract:
A terminal contact assembly is provided for hermetically sealing the interior and the exterior of an electronic device. The terminal contact assembly includes a terminal contact extending through an opening in the housing of the electronic device. The terminal contact has an inner end within the interior of the electronic device and an outer end. A deformable seal is positioned about the terminal contact within the opening through the housing. An inner insulator is positioned within the interior of the electronic device adjacent the inner surface thereof and an outer insulator is positioned about the terminal contact adjacent the outer surface of the housing. A torque generating structure generates a deformable force on the seal such that the seal seals the opening through the housing.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates generally to electromechanical parts, and in particular, to a hermetically sealed terminal for functionally linking the interior and the exterior of an electro-mechanical device particularly adapted for use in an aerospace vehicle.  
         BACKGROUND AND SUMMARY OF THE INVENTION  
         [0002]    As is known, electromechanical parts are used for countless applications in a wide variety of environments. These electromechanical parts often contain electronic devices having electrical circuits that are sensitive to the environments in which the electromechanical parts are exposed. In order to protect the circuits, many electronic devices include housings for the circuits that hermetically seal the interiors of the electronic devices from the exteriors thereof so as to limit the exposure of the components of the electrical circuits to the environment. It can be appreciated that the electrical circuit within the housing of an electronic device must be functionally linked to electrical and/or mechanical parts outside of the housing by a terminal.  
           [0003]    Heretofore, in order to hermetically seal an electronic device having a terminal extending through the housing thereof, the terminal would be either soldered or welded to the housing so as to prevent leakage into the device from about the terminal. However, the soldering or welding of the terminal to the housing of the electronic device has certain inherent weaknesses when the electronic device is used in an application such as an aerospace vehicle. By way of example, the solder or weld used to mount the terminal can be sensitive to the abrupt temperature changes that occur as the aerospace vehicle cycles between ground and a high altitude. As a result, cracks may occur in the solder or weld thereby resulting is a loss of the seal, a reduction of insulation resistance and a reduction of the dielectric withstanding voltage. In addition, the repeated expansion and contraction of the housing of the electronic device due to repeated pressure changes that occur as the aerospace vehicle cycles between ground and a high altitude may also cause the solder or weld to crack. This, in turn, exposes the electrical circuit within the housing to the external environment, which may cause the premature failure of the electrical circuit.  
           [0004]    Therefore, it is a primary object and feature of the present invention to provide a terminal for an electronic device that hermetically seals the interior from the exterior thereof.  
           [0005]    It is a further object and feature of the present invention to provide a terminal for an electronic device maintains its integrity when used in a wide range of environments.  
           [0006]    It is a still further object and feature of the present invention to provide a terminal for an electronic device that less expensive and simple to mount to the housing of the electronic device.  
           [0007]    In accordance with the present invention, a terminal contact assembly is provided for mounting to an electronic component defining an interior and exterior and having an opening therebetween. The contact assembly includes a terminal contact positionable within the opening of the electronic component. The terminal contact having inner and outer ends. A deformable o-ring is positioned about the terminal contact within the opening through the electronic component for hermetically sealing the interior of the electronic component.  
           [0008]    The assembly further includes an inner insulator positioned within the interior of the electronic component adjacent the o-ring and an outer insulator extending about the terminal contact. The inner insulator includes an enlarged head positioned on the interior of the electronic component and a neck extending therefrom. The neck of the inner insulator is receivable in the opening of the electronic component. The terminal contact includes a radially extending disc projecting therefrom within the interior of the electronic component. A nut is threadable on the inner end of the terminal contact. The nut compresses the inner and outer insulators between the disc and the nut so as to generate a deforming force on the o-ring.  
           [0009]    In accordance with a further aspect of the present invention, a terminal contact assembly is provided for mounting to an electronic component. The electronic component defines an interior and an exterior, and has an opening therebetween. The contact assembly includes a terminal contact extending through the opening in the electronic component. The terminal contact has inner and outer ends. A deformable o-ring is positioned about the terminal contact within the opening through the electronic component. A torque generating structure generates a deformable force on the o-ring such that the o-ring seals the opening through the electronic component.  
           [0010]    The assembly may also include an inner insulator positioned within the interior of the electronic component adjacent the o-ring. An outer insulator extends about the terminal contact such that the inner insulator and the outer insulator capture the o-ring therebetween. The inner insulator includes an enlarged head positioned in the interior of the electronic component and a neck extending therefrom. The neck is receivable in the opening in the in the electronic component.  
           [0011]    It is contemplated that the terminal contact include a radially extending disc projecting therefrom. A torque generating structure, such as a nut, is threadable on the inner end of the terminal contact for compressing the inner and outer insulators between the disc and the nut. It is contemplated form the inner and outer insulator from a high friction resistance material such as polyethermide.  
           [0012]    In accordance with a further aspect of the present invention, a terminal contact assembly is provided for mounting to an electronic component. The electronic component has an inner surface defining an interior, an exterior surface and an opening therebetween. The contact assembly includes a terminal contact extending through the opening of the electronic component. The terminal contact has an inner end within the interior of the electronic component and an outer end. A deformable o-ring is positioned about the terminal contact within the opening through the electronic component. An outer insulator is positioned adjacent the exterior surface of the electronic component. An inner insulator extends about the terminal contact. The inner insulator includes a base portion and a neck portion extending into the opening. A torque generating structure generates a deformable force on the o-ring such that the o-ring seals the opening through the electronic component.  
           [0013]    The terminal contact includes a radially extending disc projecting therefrom. The torque generating structure includes a nut threadable on the inner end of the terminal for compressing the inner and outer insulators between the disc and the nut. The inner and outer insulator is formed from a high friction resistance material such as polyethermide. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The drawings furnished herewith illustrate a preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will be readily understood from the following description of the illustrated embodiment.  
         [0015]    In the drawings:  
         [0016]    [0016]FIG. 1 is an exploded, isometric view of a terminal contact assembly in accordance with the present invention;  
         [0017]    [0017]FIG. 2 is a bottom plan view of the terminal contact assembly of the present invention;  
         [0018]    [0018]FIG. 3 is a cross-sectional view of the contact assembly of the present invention taken along line  3 - 3  of FIG. 2; and  
         [0019]    [0019]FIG. 4 is a cross-sectional view, similar to FIG. 3, showing an alternate embodiment of the terminal contact assembly of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    Referring to FIGS. 1-3, a terminal contact assembly in accordance with the present invention is generally designated by the reference numeral  10 . The terminal contact assembly  10  is intended to be mounted within an opening  12  extending through a housing  14  of an electrical component that is particularly adapted to be used in an aerospace vehicle. By way of example, housing  14  includes inner surface  16  defining the interior of the electrical component and outer surface  18  communicating with the environment external of housing  14 .  
         [0021]    Terminal contact assembly  10  includes terminal  20  having outer end  22  and inner end  24 . Terminal  20  is defined by a generally cylindrical outer surface  26 . Disc  28  projects radially from outer surface  26  of terminal  20  and terminates at a radially outer edge  30 . Outer edge  30  of disc  28  extends between first and second faces  32  and  34 .  
         [0022]    Outer surface  26  of terminal  20  includes a threaded outer portion  26   a  extending from outer end  22  of terminal  20  to face  32  of disc  28 . In addition, outer surface  26  of terminal  20  includes a threaded inner portion  26   b  that extends between inner end  24  of terminal  20  and thread-free portion  26   c  of outer surface  26  of terminal  20 . Thread free portion  26   c  of outer surface  26  of terminal  20  extends between inner portion  26   b  of outer surface  26  of terminal  20  and face  34  of disc  30 .  
         [0023]    Terminal contact assembly  10  further includes a generally disc-shaped outer insulator  36  having inner face  38  engageable with outer surface  18  of housing  14  and outer face  40  engageable with face  34  of disc  28 . Inner face  38  of outer insulator  36  and outer face  40  of outer insulator  36  are interconnected by radially outer edge  42  and by radially inner edge  44 . Inner edge  44  of outer insulator  36  defines an opening  46  through outer insulator  36  for receiving terminal  20  therethrough. It is contemplated that the diameter of opening  46  in outer insulator  36  is generally equal to the diameter of terminal  20  and that outer insulator  36  be formed from a high friction resistance material such as polyethermide.  
         [0024]    Terminal contact assembly  10  further includes o-ring  48  and inner insulator  50 . It is contemplated to form O-ring from a synthetic rubber and to form insulator  50  from a high friction resistance material such as polyethermide. O-ring  48  has an inner diameter generally equal to the diameter of terminal  20  and an outer diameter generally equal to the diameter of opening  12  in housing  14 . Inner insulator  50  includes a disc portion  52  defined by inner face  54  and outer face  56  that is engageable with inner surface  16  of housing  14 . Inner face  54  and outer face  56  of disc portion  52  of inner insulator  50  are interconnected by radially outer edge  58 . Neck  60  extends from outer face  56  of disc portion  58  of inner insulator  50  and has an outer surface  62 . Neck  60  terminates at terminal end  64  and has a diameter generally equal to the diameter of opening  12  through housing  14 . Opening  66  extends through inner insulator  50  between inner face  54  of disc portion  52  and terminal end  64  of neck portion  62 . Opening  66  through inner insulator  50  has a diameter generally equal to the diameter of terminal  20 . Nut  68  is receivable an inner portion  24  of terminal  20  and includes a generally flat insulation engaging face  70  for engaging inner face  54  of disc portion  52  of inner insulator  50 , as hereinafter described.  
         [0025]    In order to mount terminal contact assembly  10  to housing  14 , inner end  24  of terminal  20  is inserted through opening  46  in outer insulator  36  such that outer face  40  of outer insulator  36  engages face  34  of disc  30 . Thereafter, inner end  24  of terminal  20  is inserted through opening  12  in housing  14  such that inner face  38  of outer insulator  36  engages outer face  18  of housing  14 . As described, outer insulator  36  is captured on thread-free portion  26   c  of outer surface  26  of terminal  20  between disc  30  and housing  14 .  
         [0026]    With terminal  20  extending through opening  12  in housing  14 , o-ring  48  is slid over inner end  24  of terminal  20  into opening  12  in housing  14  such that the inner diameter of o-ring  48  sealably engages thread-free portion  26   c  of outer surface  26  of terminal  20  and such that outer diameter of o-ring  48  sealably engages housing  14 . Similarly, inner insulator  50  is slid over inner end  24  of terminal  20  such that terminal  30  extends through opening  66  in inner insulator  50 . Nut  68  is threaded onto inner end  24  of terminal  20  so as to urge neck  60  of inner insulator  50  into engagement with o-ring  48  in opening  12  through housing  14 . As nut  68  is threaded further onto threaded portion  26   b  of outer surface  26  of terminal  20 , o-ring  48  is compressed between inner face  38  of outer insulator  36  and terminal end  64  of neck  60  of inner insulator  50 . As a result, the shape of o-ring  48  deforms such that o-ring  48  hermetically seals the interior of housing  14  from the environment outside of housing  14 . It can appreciated that due to the compression of frictional resistance between terminal  20 , housing  14  and inner and outer insulators  50  and  36 , respectively, a low level of assembly torque may be utilized to thread nut  68  onto inner end  24  of terminal  20 . This, in turn, reduces the time necessary to mount the terminal contact assembly to housing  14 . In addition, the terminal contact assembly  10  of the present invention is capable of better absorbing the mechanical stresses to which an electrical device may be exposed then prior art rigid interlocks produced by soldering, brazing or welding a terminal contact assembly in position.  
         [0027]    Referring to FIG. 4, an alternate construction of a terminal contact assembly in accordance with the present invention is generally designated by the reference numeral  72 . Terminal contact assembly  72  includes common components as terminal contact assembly  10 , and as such, common reference characters are used hereinafter to refer to these common components. Similar to terminal contact assembly  10 , it is intended that terminal contact assembly  72  be mounted within opening  12  through housing  14 . Terminal contact assembly  72  includes a generally disc shaped outer insulator  74  having an outer face  76  and an inner face  78  engageable with outer surface  18  of housing  14 . Outer face  76  and inner face  78  of outer insulator  74  are interconnected by a radially outer edge  80  and a radially inner edge  82  that defines an opening therethrough. Recessed surface  84  extends between inner edge  82  and inner face  78  of outer insulator  74  for receiving o-ring  86  therein.  
         [0028]    O-ring  86  includes a generally conical outer surface  88  engageable with recess surface  84  of outer insulator  74  and an inner face  90 . O-ring  86  has an opening  92  therethrough having a diameter generally equal to the diameter of terminal  20 . O-ring  86  has an outer diameter greater than the diameter of opening  12  through housing  14 , for reasons hereinafter described.  
         [0029]    Terminal contact assembly  72  further includes inner insulator  94 . Inner insulator  94  includes a disc portion  96  having an inner face  98  and an outer face  100  engageable with inner face  16  of housing  14 . A generally cylindrical inner neck  101  extends from inner face  98  of disc portion  96  and terminates at terminal end  102 . Similarly, outer neck  104  extends from outer face  100  of disc portion  96  of inner insulator  94  and terminates at terminal end  106 . Neck  104  has an outer diameter generally equal to the diameter of opening  12  through housing  14 . Inner insulator  94  further includes an inner surface  108  that defines a passageway  108  extending through inner insulator  94  from terminal end  102  of inner neck  100  to terminal end  106  of outer neck  104  to accommodate terminal  20 . It is contemplated to provide threads on inner surface  108  of inner insulator  94  that form a mating relationship with the threads on inner portion  26   b  of outer surface  26  of terminal  20 , for reasons hereinafter described.  
         [0030]    In order to mount terminal contact assembly  72  to housing  14 , inner end  24  of terminal  20  is inserted through opening in outer insulator  74  such that outer face of outer insulator engages face  34  of disc  30 . Inner end  24  of terminal  20  is then inserted through opening  92  in o-ring  86  such that outer surface  88  of o-ring  86  engages recessed surface  84  of outer insulator  74 . Thereafter, inner end  24  of terminal  20  is inserted through opening  12  in housing  14  such that inner face  78  of outer insulator  74  engages outer surface  18  of housing  14  and such that o-ring  86  overlaps opening  12  through housing  14 .  
         [0031]    With terminal  20  extending through opening  12  in housing  14 , inner insulator  94  is threaded onto inner portion  26   b  of outer surface  26  of terminal  20 . As inner insulator  94  is threaded further onto terminal  20 , o-ring  86  is compressed between recessed surface  84  of outer insulator  74  and outer face  100  of inner insulator  94  such that o-ring  48  deforms within opening  12  and hermetically seals the interior of housing  14  from the environment outside of housing  14 . Once again, it can be appreciated that due to the compression friction resistance between outer insulator  74 , housing  14 , terminal  20  and inner insulator  94 , a low level of assembly torque may be utilized to thread inner insulator  94  onto inner end  24  of terminal  20 .  
         [0032]    As described, it is intended that terminal contact assembly  10  be mounted to an electronic component particularly adapted for use in an aerospace vehicle. It is intended that terminal contact assembly  10  hermetically seal the interior of housing  14  from the exterior thereof when the electronic component is exposed to temperatures ranging from −55° Celsius to 125° Celsius. Further, it is intended that terminal contact assembly  10  maintain its seal within opening  12  in housing  14  as the aerospace vehicle repeatedly cycles between ground and altitudes of up to 80,000 feet above sea level.  
         [0033]    Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.