Abstract:
A backshell adapter assembly includes a clamp body and one or more extending strain relief arms, pivotably connected to the clamp body. The strain relief arms are adapted to receive a pair of opposing saddle clamps or cable tie to provide radial clamping of a wire bundle relative to the backshell adapter assembly to prevent axial movement of the cable in response to axial forces thereupon. The extending strain relief arms are adapted to be rotated between various positions including −90° to +90°. Provisions may be provided for securing the extending arms at various detent positions relative to the axis of the clamp body. As such the need for separate tooling for different configurations is eliminated, thus lowering the cost of the device. In addition, the use of such backshell adapter assemblies is greatly simplified.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an accessory for an electrical connector, also known as a backshell adapter assembly, and more particularly to a backshell adapter assembly which includes one or more pivotable strain relief arms which can be adjusted between various angles relative to the axis of the backshell adapter assembly to provide radial clamping of a wire bundle to prevent axial forces from damaging the wire termination at the electrical connector. 
     2. Description of the Prior Art 
     Backshell adapter assemblies are generally known in the art. Such backshell adapter assemblies normally provide a transition from a plurality of electrical conductors to an electrical connector. An example of a backshell adapter assembly is disclosed in commonly owned U.S. Pat. No. 5,580,278, hereby incorporated by reference. 
     Various types of backshell adapter assemblies are known and configured to provide a relatively wide range of options, depending on the particular application. One such application is strain relief. In particular, backshell adapter assemblies are known which provide a radial clamping force relative to the wire bundle to prevent axial forces from damaging the termination of the wires at the electrical connector. Such known backshell adapter assemblies normally include a mechanical saddle clamp which, in turn, includes a pair of complementary saddle bars, rigidly secured to the backshell adapter assembly by way of extending strain relief arms. Conventional fasteners are used to tighten the saddle bars together to provide a radial clamping force to prevent the cable or wire bundle from moving in an axial direction. 
     Depending on the application, various configurations of the backshell adapter assemblies with saddle clamps are known in which the angle of the axes of the strain relief arms relative to the axis of the backshell adapter assembly varies. For example, 0°, 45° and 90° configurations are all known. In each of these configurations, the backshell adapter assembly includes a pair of extending strain relief arms for connecting the saddle clamps to the backshell adapter assembly, fixed at either 0°, 45° or 90° relative to the axis of the backshell adapter assembly. Since the strain relief arms are fixed relative to the backshell adapter assembly, the 0°, 45° and 90° backshell adapter assemblies with strain relief must be manufactured as separate products. As such, separate tooling must be provided for each of the various configurations which increases the cost of backshell adapter assemblies with a strain relief function. In addition, the end user must have an accurate count of each of the configurations required before ordering the backshell adapter assemblies. Should a field change be required, additional backshell adapter assemblies may be required to be ordered. As such there is a need to optimize backshell adapter assemblies with various configurations. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention relates to a backshell adapter assembly which includes a clamp body and one or more extending strain relief arms, pivotably connected to the clamp body. The strain relief arms are adapted to receive a pair of opposing saddle clamps or a cable tie to provide radial clamping of a wire bundle relative to the backshell adapter assembly to prevent axial movement of the cable in response to axial forces thereupon. The extending strain relief arms are adapted to be rotated between various positions, for example, −90° to +90°. Provisions may be provided for securing the extending arms at various detent positions relative to the axis of the clamp body. As such the need for separate tooling for different configurations is eliminated, thus lowering the cost of the device. In addition, the use of such backshell adapter assemblies is greatly simplified. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     These and other advantages of the invention will be readily apparent upon consideration of the following specification and attached drawing wherein: 
     FIG. 1 is a perspective view of one embodiment of a backshell adapter assembly with a pivotable strain relief mechanism in accordance with the present invention, shown at 0° relative to the axis of the backshell adapter assembly and illustrated clamping a shielded cable. 
     FIG. 2 is an exploded perspective view of the backshell adapter assembly illustrated in FIG.  1 . 
     FIG. 3 is a front view of the backshell adapter assembly illustrated in FIG. 1, shown partially in section. 
     FIG. 4 is a front view of the backshell adapter assembly illustrated in FIG. 1, shown with the strain relief members configured at a first angle relative to the axis of the backshell adapter assembly. 
     FIG. 5 is similar to FIG. 4 shown configured at a second angle. 
     FIG. 6 is similar to FIG. 4 but shown with the strain relief members configured at a third angle. 
     FIG. 7 is similar to FIG. 4, but shown partially in section and configured at a fourth angle. 
     FIG. 8 is a perspective view of an alternate embodiment of the invention in which the strain relief arms are configured to receive a cable tie, shown with the strain relief arms at 0° relative to the axis of the backshell adapter assembly. 
     FIG. 9 is similar to FIG. 8 except it is a front view, shown partially in section. 
     FIG. 10 is a sectional view of the strain relief arm illustrated in FIGS. 8 and 9. 
     FIG. 11 is a perspective view of an alternate embodiment of the strain relief arm in accordance with present invention formed with a planetary gear around the pivot axis. 
     FIG. 12 is an exploded perspective view of a backshell adapter assembly which incorporates the strain relief arm illustrated in FIG.  11 . 
     FIG. 13 is perspective view of another alternate embodiment of the strain relief arm in accordance with the present invention formed with a locking pin. 
     FIG. 14 is an exploded perspective view of a backshell adapter assembly which incorporates the strain relief arm illustrated in FIG. 13 
     FIG. 15 is similar to FIG. 1 except the backshell adapter assembly is configured for use with a non-shielded cable. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to a backshell adapter assembly which includes pivotable strain relief arms that are adapted to rotate between various angles, for example −90° to +90°, defined between a cable axis  22  (FIG. 5) and an axis  21  of the backshell adapter assembly. As used herein, the term configuration refers to the relationship between the axis  20  and the axis  22  as shown in FIG.  5 . The backshell adapter assembly in accordance with the present invention eliminates the needs to provide separate tooling for backshell adapter assemblies having different configurations. Not only do the pivotable strain relief arms reduce the cost of such backshell adapter assemblies but also facilitate the use of such devices. In particular, an accurate count of all of the various configurations is no longer required in order to order the backshell adapter assemblies. With the present invention, the user now need only determine the total number of backshell adapter assemblies required for the job. 
     Four embodiments of the invention are illustrated. FIGS. 1 through 7 illustrate a first embodiment of a backshell adapter assembly with pivotable strain relief arms in accordance with the present invention which utilize a saddle clamp to provide a radial clamping force on a cable. In an alternate embodiment of the invention, as illustrated in FIGS. 8 and 9, one or more strain relief arms may be provided and configured to be secured to the cable by way of a cable plastic tie. FIGS. 11 and 12 illustrate a third embodiment while FIGS.  13  and  14  illustrate a fourth embodiment of the invention. In all aspects of the invention, the strain relief arms are easily field configured to provide virtually any configuration of the strain relief arms, for example, −90° to +90°. 
     Additionally, the principles of the present invention are applicable to both shielded and non-shielded cable applications. For example, FIGS. 1-14 illustrate backshell adapter assemblies configured for use with shielded cables. FIG. 15 illustrates an exemplary embodiment of a backshell adapter assembly in accordance with the present invention, configured for use with non-shielded cables. 
     Moreover, specific locking mechanisms are shown with specific detent positions. The principles of the present invention are applicable to embodiments with various types of locking mechanisms in addition to those shown and embodiments without detent positions. It is only important that the strain relief arms be secured in place after the assembly has been configured to the desired angle. 
     Turning to FIGS. 1-7, the backshell adapter assembly with pivotable strain relief arms in accordance with the present invention is generally identified with the reference numeral  26 . The backshell adapter assembly  26  includes a clamp body  28  formed, for example, from various materials, such as an aluminum alloy, stainless steel or a composite plastic material. The clamp body  28  includes a ring portion  30  (FIG. 2) and two flat surfaces or plate portions  32  and  34 . The plate portions  32  and  34  are spaced apart and disposed to be generally parallel to the axis  20 . The plate portions  32  and  34  are connected to the ring portion  30  by a pair of shoulders  36  and  38 . The spacing between the plate portions  32  and  34  as well as the diameter of the ring portion  30  are selected to receive a cable  40 , for example, a shielded cable as shown in FIG. 1 or alternatively are configured to receive a non-shielded cable (not shown) as in the embodiment illustrated in FIG.  15 . 
     The ring portion  30  may be provided with a number of extending tabs  44 ,  46 ,  48  and  50 , which extend in an axial direction. These tabs  44 ,  46 ,  48  and  50  cooperate with corresponding slots, generally identified with the reference numeral  52 , formed in a cable termination ring  53 . The cable termination ring  53  is secured to the cable  40  and does not form a part of the back shell adapter assembly  26 . The cable termination ring  53  and in particular the slots  52  formed therein cooperate with the axially extending tabs  44 ,  46 ,  48  and  50  on the ring portion  30  of the clamp body  28  to prevent rotation of the cable  40  relative to the backshell adapter assembly  26 . One or more grounding rings  55 ,  103  may be provided. The grounding rings  55 ,  103  may be used in applications where a continuous electrical ground path is required from the cable shield to the clamp body  28  and electrical connector  104  to provide RFI/EMI shielding. The grounding rings  55 ,  103  are not required in non-shielded cable applications. 
     In accordance with an important aspect of the invention, the flat surface plate portions  32  and  34  of the clamp body  28  are provided with aligned apertures  54  and  56  which define a pivot axis  58 . These apertures  54  and  56  are used to pivotably attach a pair of opposing strain relief arms  59  and  60  to the clamp body  28 . Once the desired configuration angle is selected, the strain relief arms  59  and  60  are secured in place. Various means may be used to secure the stain relief arms  59  and  60  relative to the plate portions  32  and  34  of the clamp body  28 . As shown, a plurality of apertures, generally identified with the reference numeral  61 , are radially disposed along an extending arcuate surface  62  of the plate portions  32  and  34 . These apertures  61  define detent positions which enable the strain relief arms  59  and  60  to be locked at various detent configuration angles relative to the clamp body  28 . Five apertures  60  are shown. More or less apertures may be used. Other configurations are contemplated which do not require detent positions. In those configurations (not shown), the clamp body  28  need not include the apertures  61 . All such configurations are considered to be within the broad scope of the invention. 
     In the exemplary embodiment illustrated, the strain relief arms  59  and  60  are provided with a pair of apertures  64  and  66 . These apertures  64  and  66  are adapted to be aligned with the apertures  54  and  56  in the plate portions  32  and  34 , respectively, of the clamp body  28  to enable the strain relief arms  59  and  60  to be pivotably coupled to the clamp body  28  with suitable fasteners  68  and  70 . The fasteners  68  and  70  may be pins, rivets or screws or any means which enables the strain relief arms  59  and  60  to pivot with respect to the clamp body  28 . In the embodiments illustrated, the strain relief arms  59  and  60  may also be provided with a pair of spaced apart apertures  72  and  74  that are adapted to be aligned with one of the apertures  61  along the extending arcuate surfaces  62  of the plate portions  32  and  34  of the clamp body  28 . These apertures  72  and  74  enable the strain relief arms  59  and  60  to be secured at a selected configuration angle relative to the clamp body  28  by way of suitable fasteners  76  and  78 . Various types of fasteners, such as pins, rivets and screws may be used for the fasteners  76  and  78 . 
     The strain relief arms  59  and  60  may be formed with extending flange portions  82  and  84 . These extending flange portions  82  and  84  may be used to secure a pair of opposing saddle bars  86  and  88 . Each of the saddle bars  86  and  88  may be formed with apertures, generally identified with the reference numeral  93 , on opposing ends. These apertures  93  are adapted to be aligned with the apertures  82  and  84  on the flange portions  82  and  84  to enable the saddle bars  86  and  88  to be secured to the strain relief arms  59  and  60  with suitable fasteners, for example, a pair of screws  94  and  100  and a pair of elongated captured nuts  96  and  98 . 
     As shown in FIGS. 4-7, various configurations of the strain relief arms  59  and  60  can be obtained rather quickly and easily, thus simplifying the manufacturing process as well as ordering process for backshell adapter assemblies with strain relief capabilities. For example, FIG. 4 illustrates a 0° configuration in which the axis  22  of the strain relief arms  59  and  60  is at 0° relative to the axis  20 . FIG. 5 illustrates a configuration in which axis  22  of the strain relief arms  59  and  60  form a positive angle relative to the axis  20 , for example +45°. FIG. 6 illustrates a configuration in which the axis  22  of the strain relief arms  59  and  60  forms a negative angle relative to the axis  22 , for example −90°, while FIG. 7 illustrates a configuration at −45°. Various angular configurations are possible depending on the radial location of the apertures  61  along the arcuate surfaces  62  of the clamp body  28  in the embodiment shown in FIGS. 1-3. 
     Each of the leaf springs  108  and  110  includes a pin  114 ,  116  that is adapted to be received in apertures  118  provided in the coupling nut  106 . The coupling nut  106  also includes internal threads, generally identified with the reference numeral  120 , that are adapted to mate with corresponding threads  122  on the electrical connector  104  or another backshell. 
     The electrical connector  104  further includes anti-rotation teeth, generally identified with the reference  126 , which cooperate with corresponding teeth  128  formed on the termination ring  52 , to prevent rotation of the electrical connector  104  relative to the backshell adapter assembly  26 . 
     An alternate embodiment of the invention as illustrated in FIGS. 8 and 9. This embodiment is similar to the embodiment illustrated in FIGS. 1-7 with the exception of the configuration of the strain relief arms  59  and  60 . In this embodiment, the strain relief arms, generally identified with the reference numeral  133 , are configured to eliminate the need for a saddle clamp. In this embodiment, one or two strain relief arms  133  may be provided and radially disposed adjacent the clamp body  28 . The strain relief arms  133  are configured with a notch  130  disposed between a stop  132  and a shoulder  134 . The configuration is adapted to capture a cable tie  136  within the notch  130  to enable the strain relief arm  133  to be secured to the cable  40 . The strain relief arm  133  is adapted to pivot relative to the clamp body  28  in a similar manner as the embodiments illustrated in FIGS. 1-7 and thus includes an apertures  129 . In embodiments, such as illustrated in FIG. 8, the strain relief arm  133  may be provided with a second aperture  131  for preventing rotation of the strain relief arm  133  relative to the clamp body  28 . The second aperture  131  may be omitted when detent positions are not desired and in embodiments of the strain relief arms which include other locking mechanisms, such as planetary gear, similar to FIG. 11, or a locking pin, similar to FIG.  13 . 
     The embodiment illustrated in FIGS. 8 and 9 contemplate the use of one or two strain relief arms  133 . In configurations in which two strain relief arms  133  are utilized, the clamp body  28  is the same as illustrated in embodiment illustrated in FIGS. 1-7. In an embodiment in which only one strain relief arm  133  is utilized, the clamp body is essentially the same as the clamp body  28  (FIG. 2) except only a single plate portion  32  is provided. The clamp body  28  is also used in embodiments in which the strain relief arm  133  is provided with a locking pin, similar to FIG.  13 . Moreover in embodiments in which the strain relief arms  128  are provided with a locking mechanism, such as a planetary gear, similar to FIG. 11, a clamp body similar to FIG. 12 may be utilized. 
     The third embodiment of the invention is illustrated in FIGS. 11 and 12. In this embodiment, alternate strain relief arms  140 ,  141  are provided as illustrated in FIG.  11 . The strain relief arms  140 ,  141  each include a plate portion  142  and an extending flange  144 . The plate portion  142  is provided with an aperture  146  which defines a pivot axis for the strain relief arms  140 ,  141 . In this embodiment, various types of locking mechanisms are contemplated, for example, raised or recessed star gears, planetary gears or the like may be used to lock the strain relief arms  141 ,  142  in the position relative to the clamp body  154 . An exemplary embodiment illustrating a planetary gear is illustrated. The planetary gear, generally identified reference  148 , is concentrically formed around the aperture  146  and includes a plurality of teeth  149 . The planetary gears  148  is adapted to cooperate with a corresponding planetary gear  150  formed in the flanged portion  152  of a clamp body  154  (FIG.  12 ). The flange portion  152  of the clamp body  154  also includes an aperture  156  concentrically disposed relative to the planetary gear  150 . The planetary gears  148  and  150  prevent rotation of the strain relief arms  140 ,  141  when secured to the clamp body  154  while allowing virtually any configuration of the strain relief arms  140 ,  141  relative to the axis  20 . Conventional fasteners  158  and  160  may be used to secure the strain relief arms  140  and  141  to the clamp body  154 . In particular, once the desired configuration angle is selected, the aperture  146  in the strain relief arms  140  and  141  are aligned with the apertures  156  in the clamp body  154  and secured thereto by the fasteners  158  and  160 . The fasteners  158  and  160  may either be loose as shown or captured relative to the strain relief arms  140 ,  141 . The clamp body  154  is otherwise similar to the clamp body  28  (FIG.  2 ). The flange portions  144  of the strain relief arms  140  and  141  also include aperture  162  and  163  for securing a pair of saddle bars  86  and  88  thereto with conventional fasteners  94 ,  96 ,  98  and  100 . 
     An alternate embodiment of the invention is illustrated in FIGS. 13 and 14. This embodiment is similar to the embodiment illustrated in FIGS. 1-7 except that the strain relief arms  170  and  172  are provided with locking pins  174  and  176 . The locking pins  174 ,  176  are adapted to be received in the apertures  61  in the clamp body in lieu of fasteners. In all other respects, the embodiment illustrated in FIGS. 13 and 14 are virtually the same as the embodiment illustrated in FIGS. 1 through 7. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described above.