Abstract:
A transducer including a transducer body, a sensor associated with the transducer body, an electrical connector assembly fastened to an end of the transducer body, and a vibration damper system disposed between the end of the transducer body and the electrical connector assembly. The vibration damper system being operative for attenuating vibrational acceleration and amplification forces experienced by the electrical connector assembly when the transducer is exposed to vibration.

Description:
FIELD OF INVENTION 
   This invention relates to a transducer and more particularly, to a transducer having an electrical connector assembly that is isolated from the transducer body by a vibration damper system. 
   BACKGROUND OF THE INVENTION 
   Pressure sensors, or any other transducers, may be required to operate in extreme environments. Transducers designed for use in aircraft or on-engine applications are exposed to high levels of vibration. Some vibration levels can approach and exceed 300 g&#39;s. 
     FIG. 1  shows an embodiment of a conventional transducer  10  used in high vibration environments. The transducer  10  includes an elongated, transducer body  11  having a first end  12  that defines an end surface  13  for mounting the transducer  10 , for example, to the surface of an aircraft wing or engine. Space constraints at the transducer location may require that the transducer&#39;s electrical connector assembly  14 , which is comprised of an electrical connector  14   a , a mating connector half  14   b , and a wiring harness (not shown), be mounted to a second end  15  of the transducer body  11 , or other location, where the vibration and structure amplify the force experienced at the electrical connector assembly or other critical weld. To minimize amplification force of the vibration at the connector assembly, it is preferred to have the connector assembly and its associated mass as low as possible, and to locate the connector assembly to decrease the cantilever length. Space constraints, however, may preclude this construction. 
   The electrical connector assembly&#39;s  14  size is typically minimized to reduce the weight of the transducer, and reduce its the cost. These requirements also reduce the size of the weld  16  attaching the connector assembly to the transducer body  11 . The reduced size of the weld  16  reduces its load capacity, which is comprised of the electrical connector  14   a , the mating connector half  14   b , and the wiring harness of the electrical connector assembly  14 . Exceeding this critical load at vibration, with the acceleration and amplification effects caused thereby, results in fracture of the weld  16  or failure of the connector assembly  14 . This may be catastrophic in a control transducer. 
   Accordingly, there is a need for a transducer that is capable of operating in high vibration environments without electrical connector assembly failure. 
   SUMMARY OF INVENTION 
   One aspect of the present invention is a transducer having an electrical connector assembly that is isolated from the transducer body by a vibration damper system. The transducer comprises a transducer body, a sensor associated with the transducer body, an electrical connector assembly fastened to an end of the transducer body; and a vibration damper system disposed between the end of the transducer body and the electrical connector assembly for attenuating vibrational acceleration and amplification forces experienced by the electrical connector assembly when the transducer is exposed to vibration. In one embodiment of the transducer, the sensor comprises a pressure sensor. 
   Another aspect of the present invention is a method of attenuating vibrational acceleration and amplification forces experienced by an electrical connector assembly of a transducer when the transducer is exposed to vibration. The method comprises the steps of providing a transducer having a transducer body, a sensor associated with the transducer body, and an electrical connector assembly fastened to an end of the transducer body, and disposing a vibration damper system between the end of the transducer body and the electrical connector assembly. In one embodiment of the method, the sensor comprises a pressure sensor. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a prior art transducer. 
       FIG. 2  is a side elevational view of a transducer according to an embodiment of the present invention. 
       FIG. 3  is a side cross-sectional view of the transducer of  FIG. 2 . 
       FIG. 4  is a first end view of the transducer of  FIG. 2 . 
       FIG. 5  is a second end view of the transducer of  FIG. 2 . 
       FIG. 6A  is a plan view of a substrate used in a vibration damper system of the transducer of  FIG. 2 . 
       FIG. 6B  is cross sectional view through line  6 B— 6 B of  FIG. 6A . 
   

   DETAILED DESCRIPTION 
   The present invention is a transducer having an electrical connector assembly that is isolated from the transducer body by a vibration damper system. The vibration damper system minimizes the effect of vibration, often experienced by transducers designed for operation in extreme environments, such as but not limited to pressure transducers used in aircraft or on-engine applications where the vibration levels can approach and exceed 300 g&#39;s. 
   Referring now to  FIG. 2 , there is shown an embodiment of a transducer  20  made according the present invention. The transducer  20  includes an elongated, transducer body  21  having a first end  22  and an opposite second end  23 . The first end  22  of the transducer body  21  defines a first end surface  22   a  for mounting the transducer  20 , for example but not limitation, to the surface of an aircraft wing or engine (not shown). The second end  23  of the transducer body  21  defines a second end surface  23   a  that mounts a vibration damper system  24  and electrical connector assembly  25 . The vibration damper system  24  is mounted directly on the second end surface  23   a  of the transducer body  21 . The electrical connector assembly  25 , in turn, is directly mounted to an end surface  24   a  of the vibration damper system  24 . One or more conventional fasteners  26  may be used for fastening the vibration damper system  24  and the electrical connector assembly  25  to the second end surface  23   a  of the transducer body  21 . 
   The vibration damper system  24  may comprise a single substrate (not shown), or in the shown embodiment, a stack of substrates  24   b . The one or more substrates  24   b  can be made from an elastic material, such as polytetrafluorethylene (TEFLON), a polymeric material such as copolymer of vinylidene fluoride and hexafluoropropene (VITON rubber) which may have a SHORE A durometer of 75, or any other material capable of attenuating the amplification and acceleration forces acting on the electrical connector assembly which are caused by vibration of the transducer. As shown in  FIG. 6A , each substrate  24   b  may comprise an annular body  24   c  having a plurality of openings  24   d . As shown in  FIG. 6B , the body  24   c  of the substrate  24   b  may have a thickness T of about 0.06 inches. 
   In the earlier mentioned single substrate embodiment, the substrate may be made from an elastomeric or polymeric material. In the stack of substrates embodiment, one or more of the substrates may be made from an elastomeric material and the remaining substrates may be made from a polymeric material. In the shown embodiment of  FIG. 2  (also shown in  FIG. 3 ), substrates  24   b  of elastomeric and polymeric material are alternatively disposed in the stack. In still a further embodiment, all the substrates of the stack may be made from an elastomeric material or from a polymeric material. 
   The attenuation provided by vibration damper system  24  of the present invention can be adjusted to one or more selected frequencies of vibration. This can be accomplished by varying the specific material composition, thickness, and durometer of the substrate or substrates  24   b.    
   As shown in  FIG. 3 , the transducer body  21  may be constructed with a cylindrical tube main body member  30 , a cylindrical feed-through glass seal header assembly  31  disposed in a one open end of the main body member  30  and welded or otherwise secured thereto, a partition member  32  with a wire pass-through opening  32   a  disposed within the tube member  30 , just behind the header assembly  31 , and a circular closure member  34  having a wire pass-through opening  34   a , disposed in the opposite open end  30   b  of the tube member  30  and welded or otherwise secured thereto. The header assembly  31  defines the earlier described first end surface  22   a  of the transducer body  21  and the closure member  34  defines the earlier described second end surface  23   a  of the transducer body  21 . 
   The feed-through glass seal header assembly  31  is well known in art (see for example U.S. Pat. No. 5,955,771, entitled SENSORS FOR USE IN HIGH VIBRATIONAL APPLICATIONS AND METHODS FOR FABRICATING SAME issued to Kurtz et al.). The feed-through glass seal header assembly shown in  FIG. 3  includes low pressure sensor  31   a  and high pressure sensor  31   b . Low and high pressure ports  31   c ,  31   d  extend through the header assembly  31  from the first end surface  22   a , and communicate with respective ones of the first and second pressure sensors  31   a ,  31   b . The header assembly  31  further includes an upper flange  31   e  and lower corner flanges  31   f  ( FIG. 4 ). The flanges  31   e ,  31   f  have apertures  31   g  for receiving conventional fasteners, which fasten the transducer  20  to the surface of the device it is intended to be used for. 
   The partition member  32  mounts a circuit board  33  that carries various transducer electronics  33   a . Since such electronics are well known in the art, no further description the electronics  33   a  is needed and will not be provided herein. The feed-through glass seal header assembly  31  maintains the transducer electronics  33   a  in a hermetically sealed environment. 
   The electrical connector assembly  25  includes an electrical connector  25   a , a mating connector half  25   b , and a wiring harness (not shown). In the shown embodiment, the mating connector half  25   b  is formed by a cylindrical, cap-like housing  26 . The closure mating end (open end) of the housing  26  may be surrounded by a circular, peripheral flange  26   a  that mates with the vibration damper system  24  and enables attachment of the electrical connector assembly  25  and vibration damper system  24  to the second end surface  23   c  (defined by the closure member  34  in this embodiment) of the transducer body  21 . This may be accomplished by providing one or more space apart openings  26   b  in the flange  26   a , which align with the openings  24   d  extending through the substrate or substrates  24   b  of the vibration damper system  24  and threaded closed end openings  34   b  in closure member  34 . The openings  34   b  in the closure member  34  threadedly engage screw type fasteners  40  that extend through the flange openings  26   b  and the substrate openings  24   d.    
   The housing  26  includes a side aperture  26   c  which receives the electrical connector  25   a . The electrical connector  25   a  may be welded or otherwise secured within the side aperture  26   c  of the connector housing  26 . The wires  41  of the wiring harness (not shown) extend through the connector  25   a  and the housing  26  of the mating connector half  25   b  and attach to pins  43  of an electrical feed-through  42  disposed in the wire pass-through opening  34   a  of the closure member  34 . The pins  43  of the electrical feed-through  42  are also electrically connected by wires  44  to the transducer electronics  33   c  on the circuit board  33 , thus, electrically connecting the wiring harness of the electrical connector assembly  25  to the transducer electronics  33   a.    
   The vibration damper system of the present invention enables the transducer to operate in severe vibration applications with high amplifications and accelerations as it attenuates these forces, thereby isolating the electrical connector assembly from the same. Savings in footprint real estate can also be realized by employing the vibration damper of the present invention, because it allows the electrical connector assembly  25  to be mounted at the end or top of the transducer  20 , at the highest amplification, as shown in  FIGS. 2–5 . The vibration damper system can be tuned to act as a low pass filter, attenuating frequencies above a selected critical frequency.