Abstract:
A cable constraining device features a flexible cable contact sheet that is inward attached to a cable constraining contour of a holding structure. The holding structure is configured for substantially encompassing a cable circumference while in constraining configuration. In a cavity between the holding structure and the cable contact sheet is a gel filled that provides a vibration dampening soft contact of the cable contact sheet with the cable insulation. The cushioning gel absorbs micro movement of the cable transferred onto the cable contact sheet such that wearing effects due to frictional sliding and vibration of the cable at its constraining location is substantially reduced. The holding structure may be of rubber like material that is formed on its outside like a well known grommet. An outer rigid clamping structure may be additionally employed. The device may be also configured as a profile in various lengths and bent shapes.

Description:
CONTINUATION IN PART 
     The present application is a Continuation in Part of US Parent Patent Application of the same title and inventor, application Ser. No. 12/131,096 filed 1 Jun. 2008 now U.S. Pat. No. 7,878,462. 
    
    
     FIELD OF INVENTION 
     The present invention relates to devices for constraining cables. In particular, the present invention relates to cable constraining devices utilizing an encapsulated gel cushion and/or encapsulated cushion profile for resiliently absorbing vibrations of the constrained cable. 
     BACKGROUND OF INVENTION 
     In engine driven vessels such as airplanes, helicopters, and the like, cables are exposed to tremendous vibrations that significantly contribute to the cables&#39; wear particularly at their attachment locations. Cable wear in turn is a substantial factor in reducing the overall operational safety of such engine driven vessels. This is of particularly concern for aeronautic vessels that tend to stay in service for several decades. Cable wear is also difficult to monitor, since the cables are commonly stored away making their attachment locations inaccessible for inspection. Therefore, there exists a need for a cable constraining device that provides reduced cable wear. The present invention addresses this need. 
     Conventional cable constraining devices such as grommets and cable clips commonly employ a rubber like material encompassing the cable&#39;s insulation at the attachment location of that cable. The rubber is commonly employed to protect the cable insulation against surrounding sharp edges and/or hard materials that would damage the cable insulation in a short time. Nevertheless, the rubber itself likely rubs against the cable insulation causing both to wear, which eventually results in exposure of conductive cable core. Therefore, there exists a need for a cable constraining device that substantially avoids rubbing and eventual micro sliding between the cable insulation and the contacting portion of the cable constraining device. The present invention addresses also this need. 
     In engine powered vessels, cable trees have significantly varying cable numbers along individual cable tree branches. Therefore, there exists a need for cable constraining device, that may be economically fabricated in varying dimensions to accommodate for simultaneously clamping a highly diverse number of cables. The present invention addresses also this need. In addition, simultaneous clamping of a large number of cables in a single cable constraining device bears the risk of uneven clamping pressure distributions among the individual cables eventually resulting in excessive pressure on some cables. Therefore, there exists a need for a cable constraining device capable of simultaneously clamping a large number of cables with highly uniform clamping pressure. The present invention addresses also this need. 
     SUMMARY 
     In three embodiments of the invention, a cable constraining device features a flexible cable contact sheet that is inward attached to a sheet attachment interface of a positioning structure. The positioning structure is configured for substantially encompassing a cable circumference while in constraining configuration. In a pocket between the positioning structure and the cable contact sheet is a gel filled that provides a vibration dampening soft contact of the cable contact sheet with the cable insulation. The cushioning gel absorbs micro movement of the cable transferred onto the cable contact sheet such that wearing effects due to frictional sliding and vibration of the cable at its constraining location is substantially reduced. The positioning structure may be of rubber like material that is formed on its outside like a well known grommet. 
     The positioning structure may alternately be configured as a circumferentially tight able cable clip similar for example to a well known P-clamp. In such case, the positioning structure may include an outer rigid clamping structure attached at the outside of the rubber like material that is combined on its inside with the cable contact sheet. The cable contact sheet may be of a woven fabric and/or of thin rubber like material. The cable contact sheet is sufficiently thin to absorb micro movement of the constrained cable well within its elastic range as is well known in the art. The underlying gel acts at the same time to provide at the sufficient contact pressure of the cable contact sheet with the cable circumference. 
     In a fourth embodiment of the invention, the cable constraining device is configured as a multilayer profile with a stiff clamping profile having two clamping features at each end of it. A cushion profile extends adjacent to the clamping profile in between the two clamping features and is combined with the clamping profile via a positioning profile. The flexible contact sheet peripherally encompasses the cushion profile and withholds itself along at least a portion of peripheral faces of the positioning profile. The clamping profile is of a clamping stiffness and the positioning profile is of positioning softness and positioning height such that clamping forces applied to the clamping features are distributed along the cushion profile at least in a predetermined but preferably even fashion irrespective an elastic clamping deformation of the clamping profile between the two clamping features. Due to the overall extrusion type design, the multilayer profile may be economically fabricated, lengthened and/or bent into various lengths and shapes to accommodate for example for varying numbers of cables that may need to be simultaneously clamped. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a first shaded perspective cut view of a cable portion constrained in a first embodiment of the invention. The cut plane is vertical and coinciding with cable axis CA. 
         FIG. 2  is the first shaded perspective cut view of the positioning structure of  FIG. 1 . 
         FIG. 3  is the first shaded perspective cut view of the positioning structure and gel of  FIG. 1 . 
         FIG. 4  is the first shaded perspective cut view of the positioning structure, gel and cable contact sheet of  FIG. 1 . 
         FIG. 5  is a second shaded perspective view of a second embodiment of the invention. 
         FIG. 6  is the second shaded perspective view of a third embodiment of the invention. 
         FIG. 7  is a third shaded perspective top view of a fourth embodiment of the invention in a first configuration. 
         FIG. 8  is a fourth shaded perspective bottom view of the fourth embodiment of the invention in the first configuration. 
         FIG. 9  is the fourth shaped perspective bottom view of the fourth embodiment of the invention in a second configuration. 
         FIG. 10  is the fourth shaped perspective bottom view of the fourth embodiment of the invention in a third configuration. 
         FIG. 11  is a perspective frontal view of the fourth embodiment of the invention in assembly position with clamped cables. 
         FIG. 12  is the second perspective view of the fourth embodiment in P-clamp bent configuration. 
         FIG. 13  is the third shaded perspective top view of the fourth embodiment of the invention in a fourth configuration. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a prior art cable  1  may extend with its cable core  5  and cable insulation  3  along a cable axis CA. A cable circumference  7  may surround the cable axis CA. A cable constraining device  100  in accordance with a first embodiment of the invention may include a positioning structure  105 , a flexible cable contact sheet  109  and a gel  107 . Referring to  FIG. 2 , the positioning structure  105  may have a sheet attachment interface  113 ,  115  that is radially inward facing and substantially encompassing the cable circumference  7  while in a cable constraining configuration. The cable constraining configuration may be different from a fabrication configuration as explained in detail further below. Embedded in the sheet attachment interface may be one or more gel basins  111 . Between the gel basins  111  may be a transverse seam  115  as a portion of the remaining sheet attachment interface  113 ,  115 . Circumferential seams  113  are also portions of the sheet attachment interface  113 ,  115 . The positioning structure  105  may feature an outer circumference  117  and axial faces  119  at both axial ends of it. 
     Referring to  FIGS. 3 and 4 , a flexible contact sheet  109  may be partially attached to the sheet attachment interface  113 ,  115  such that one or more pockets are defined in between the flexible contact sheet  109  and the sheet attachment interface  113 ,  115 . In case of employed gel basin(s)  111 , the pocket may be defined between the flexible contact sheet  109  and the respective gel basin  111 . Separating the gel  107  into a number of small pockets may assist in avoiding long term creep and redistribution of the gel  107  as may be well appreciated by anyone skilled in the art. In the  FIGS. 1-6 , the transverse seams  115  are depicted as being substantially parallel with the cable axis CA particularly in a second embodiment in which the cable constraining configuration is the same as the fabrication configuration. In the second embodiment depicted in  FIG. 5 , the holding structure  105  may be configured on its outside similar to a well known grommet with an outside circumferential groove  131 , which may be snapped into a clamping contour such as a mounting hole (not shown) as is well known in the art. The holding structure  105  may be initially fabricated in an injection molding process, followed by a second co-molding process where the gel  107  is applied. The flexible contact sheet  109  may be attached to the sheet attachment interface  113 ,  115  in a final fabrication stage. In case of the flexible contact sheet  109  being of rubber like material, it may be combined with the sheet attachment interface  113 ,  115  by a co-molding process as well. In case of the flexible contact sheet  109  including a fiber fabric material such as well known Kevlar™, the flexible contact sheet  109  may be glued or welded to the sheet attachment interface  113 ,  115 . Due to the closed circular shape of the holding structure  105 , the co-molding and other eventual fabrication steps are preferably performed in a direction substantially parallel to the cable axis CA. In the second embodiment, the holding structure  105  provides rough and static shape adjustment to the cable circumference  7  while the cushion(s)  117  defined by the gel  107  and the flexible contact sheet  109  provide balanced constraining pressure and dynamic damping of cable  1  micro movement and vibration. 
     Referring to  FIG. 6  and a third embodiment of the invention, the positioning structure  105  may be configured as a circumferentially tight able cable clip similar for example to a well known P-clamp. In that case, part of the holding structure  105  may be an outer rigid clamping structure  141  configured and acting for example as a well known P-clamp. The outer rigid clamping structure  141  may also be configured as other well known cable clamping structures that are either once or twice circumferentially separated to provide the circumferential tightening as is well known in the art. In the third embodiment, an intermediate rubbery structure  143  that is combined with the outer rigid clamping structure  141  is also part of the holding structure  105 . In the third embodiment, the outer rigid clamping structure  141  provides on one hand positioning stiffness and clamping firmness of the cable  1  while the intermediate rubbery structure  143  provides rough and static shape adjustment to the cable circumference  7  while the cushion(s)  117  defined by the gel  107  and the flexible contact sheet  109  provide balanced constraining pressure and dynamic damping of cable  1  micro movement and vibration. The outer rigid clamping structure  141  may have an attachment feature(s)  145  such as a well known screw hole  145  via which the cable constraining device  100  may be attached and circumferentially tightened. 
     In the third embodiment, the positioning structure  105  may be circumferentially discontinuous as shown in  FIG. 6 . Particularly in such case, the fabrication configuration of the holding structure  105  and/or the intermediate rubbery structure  143  may be straightened compared to its constraining configuration as depicted in the  FIGS. 1-6 . A straightened fabrication configuration in turn may provide more perpendicular access to the sheet attachment interface  113 ,  115 , which gives more free fabrication access to the transverse seam(s)  115  and circumferential seams  113  as may be well appreciated by anyone skilled in the art. Consequently, the transverse seam(s)  115  may be in a substantial angle with respect to the cable axis CA, which may reduce eventual long term setting of the cable  1  in between two adjacent gel cushions  117 . Also, the flexible contact sheet  109  may easily accessed for gluing, stitching, welding or co-molding to the sheet attachment interface  113 ,  115 . The final fabrication profile of the positioning structure  105  and/or intermediate rubbery structure  143 , the flexible contact sheet  109  and the gel  107  may be lengthened in conjunction with and attached inside any prefabricated cable  1  clamping contour in general and the outer rigid clamping structure  141  in particular. A cable  1  clamping contour may be for example a through hole. 
     In all embodiments, the flexible contact sheet  109 ,  211  may be of a rubber like material and/or a fiber fabric that may be woven and/or coated. The coating may also be rubber like material and/or a well known stiction coating to increase well known stiction between the flexible contact sheet  109  and the cable circumference  7 . Increasing such stiction in the interface between cable circumference  7  and flexible contact sheet  109  may also reduce friction wear there. Use of the cable constraining device  100  is similar to conventional well known grommets and cable clips. 
     Referring to  FIGS. 7-12 , the cable constraining device  200  according to a fourth embodiment of the invention is configured as a multilayer profile including a clamping profile  241 , a cushion profile  207 , a position profile  205  and the flexible contact sheet  211 . In  FIGS. 7-11 , the flexible contact sheet  211  is half removed for illustration purposes. The clamping profile  241  is preferably made of sheet metal but may be of any material and configuration to provide a clamping stiffness between the two clamping features  245  as may be well appreciated by anyone skilled in the art. The clamping profile  241  has two clamping features  245  at its longitudinal opposing ends. The two clamping features  245  may be preferably screw holes but may also be any other well known structural feature such as a hook or thread hole that may serve to receive a clamping force FC that is preferably in a substantial angle with respect to the clamping profile  241 . 
     The cushion profile  207  extends adjacent to the clamping profile  241  and in between the two clamping features  245 . The cushion profile  207  may have transverse peripheral grooves  215  that may one hand compensate for compression in case of bending the cable constraining multilayer profile as shown in  FIG. 12 . On the other hand, the transverse peripheral grooves  215  may assist in fixating cables  1  individually as shown in  FIG. 11 . In that case, the transverse peripheral grooves  215  may have a groove pitch  215 P that may correspond to a predetermined cable clamping spacing. The cable clamping spacing may be for example about the cable diameter  10  of a clamped cable  1 . The cushion profile  207  has an extension length preferably equal the extension length of the positioning profile  205 . Nevertheless, the cushion profile  207  may have an extension length that is only a fraction of the extension of the positioning profile  205  of down to less than the groove pitch  215 P. In that case, a number of cushion profiles  207  may be combined with the positioning profile  205 . 
     The positioning profile  205  also extends in between the two clamping features  245  and combines the cushion profile  207  with the clamping profile  241 . The positioning profile  205  has a cushion profile connecting face  208  along which the cushion profile  207  is attached, clamping profile connecting face(s)  206  along which the clamping profile  241  is attached, and peripheral faces  209  along at least a portion of which the flexible contact sheet  211  is withholding itself while peripherally encompassing the cushion profile  207 . The positioning profile  205  has a positioning height  205 H between the clamping profile  241  and the cushion profile  207  and is preferably of a rubber type material of a positioning softness. Position height  205 H is selected in conjunction with the positioning softness and the clamping stiffness of the clamping profile  241  between the clamping features  245 , such that the clamping force FC is distributed along the cushion profile  207  with a predetermined pressure distribution HP irrespective an elastic clamping deformation of the clamping profile  241  between the two clamping features  245  as may be well appreciated by anyone skilled in the art. The predetermined pressure distribution HP is preferably a substantially balanced pressure distribution HP such that each clamped cable  1  is clamped with the substantially the same clamping pressure. 
     The cushion profile  207  may be made substantially softer than the positioning profile  207  to operate as described for the gel  107 . The cushion profile  207  may be made of a gel and/or a soft rubber type material. Positioning profile  205  and/or cushion profile  207  may be fabricated by well known extrusion techniques, in case of which the cushion connecting face  208  may be preferably constant in direction between the two clamping features  245 . 
     As shown in  FIG. 8 , the clamping profile connecting face  206  may at least along a section but preferably entirely between the two clamping features  245  completely transversely encompass the clamping profile  241 . In that first configuration, a most solid structural interlocking between the positioning profile  205  and the clamping profile  241  is accomplished. The flexible contact sheet  211  may be stretch tightened around the cushion profile  207  and the positioning profile  205 . In this first configuration, the sub assembly including the cushion profile  207 , the positioning profile  205  and the flexible contact sheet  211  may be substantially free of adhesive; since the stretch tightened flexible contact sheet  211  may hold the cushion profile  207  onto the positioning profile  205 . This may advantageously provide for a wider selection of different materials to be combined in the subassembly. In addition, without adhesive bond the risk of bond fatigue failure is also eliminated. 
     In a second configuration shown in  FIG. 9 , the clamping profile connecting face  206  may be at least along a section but preferably entirely between the two clamping features  245  C-like transversely encompassing the clamping profile  241 . This may be advantageous where the sub assembly needs to be snapped onto the clamping profile  241 . The flexible contact sheet  211  may be adhesively bonded or otherwise connected to the peripheral faces  209  at the lateral sides relative to the cushion profile  207  and portions of the bottom side of the positioning profile  205  opposite the cushion profile  207 . 
     In a third configuration shown in  FIG. 10 , the clamping profile connecting face  206  is at least along a section but preferably entirely between the two clamping features  245  single face adhesively combined with the clamping profile  241 . This may be advantageous in cases where the clamping profile  241  with its bottom side opposite the cushion profile  207  is directly attached to another structure. The flexible contact sheet  211  is attached to the peripheral faces  209  on the lateral sides of said positioning profile  205 . 
     The multilayer profile configuration of the cable clamp  200  provides for a simple adjustment in length and or bending contour of it. It may be for example easily bent into a P-clamp as depicted in  FIG. 12 . The flexible contact sheet  211  may again be of rubber material, or of nylon or Kevlar™ type fiber fabric with an eventual top stiction layer as described above. The positioning profile  205  and the cushion profile  207  may be a monolithically structure from either a single material or by comolding more than one separate materials. Referring to  FIG. 13  and in case of single material monolithic structure, the cushion profile  207  may be defined by structural separations or indentations  217  with locally softening effect on the material as may be well appreciated by anyone skilled in the art. 
     Accordingly, the scope of the invention described in the Specification above and the Figures is set forth by the following claims and their legal equivalent: