Patent Publication Number: US-2009230256-A1

Title: Adapter for stacking cable hangers

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention is directed toward cable hangers for securing long members such as cables to a structure, and particularly toward stackable cable hangers. 
     2, Technical Problems Posed by the Prior Art 
     Cable hangers have long been used to secure cables to a structure such as a radio tower, where the cable hangers are brackets which secure around a portion of the cable and also secure to the tower, such as a tower leg. Multiple ones of such cable hangers are typically used to secure the length of a cable to a structure. 
     For example, multiple cable hangers such as shown in U.S. Pat. No. 5,967,468 have been used to attach a single cable to a tower. U.S. Pat. No. 4,763,132 similarly illustrates a waveguide hanger for attaching a single waveguide to a tower. (As used herein, references to cable are meant to incorporate not only cables but also other longitudinal members such as waveguides, having a variety of cross-sectional shapes.) When it is desired to attach more than one cable to a tower, however, this can present a problem. Particularly when a second or subsequent cable is added later, it may be difficult to attach new cable hangers to a tower since they will be blocked by the previously mounted cable hangers and supported cable. Moreover, given that such towers can extend hundreds of feet into the air, such bothersome cable attachment can be particularly frustrating and dangerous for the person whose job it is to attach the new cable. 
     Stackable hangers have also been developed, such as shown in U.S. Pat. Nos. 6,899,305 and 7,097,142, the full disclosures of which are hereby incorporated by reference. These hangers can be attached to each other to allow more than one cable to be attached to the tower where the second cable can be readily attached without concern for the fact that the first cable and its hangers may block access to attaching directly to the tower. However, stackable hangers do not necessarily provide the same mounting strength as non-stackable hangers. For example, a stackable hanger mounted on a stackable hanger may not secure its cable as well as a non-stackable hanger secures a cable directly to the tower. 
     Also, the cost of stackable hangers can be higher than non-stackable hangers such as described above. As a result, when constructing a tower where only a single cable is to be attached to a tower leg, it can be unnecessarily costly to use stackable hangers (since no stacking is required). On the other hand, if non-stackable hangers are used though only a single cable is intended to be hung (e.g., to save money during initial construction or, in the case of many older towers, as a result of the unavailability of stackable hangers when the tower was originally constructed), changing the tower to later add more cables can be extremely difficult and costly to do so. That is, retrofitting a tower with additional cables may necessitate attaching the new cables in a less than ideal manner (i.e., in a manner which works around the previously mounted cable but then results in an attachment which is not as secure as desirable). Alternatively, the old non-stackable hangers may be removed and replaced with all new stackable hangers. However, such replacement may be extremely costly, difficult and dangerous. That is, replacing old non-stackable hangers (which may have hung on the tower for years) with new stackable hangers would require detaching the old hangers from the tower and cable, which would not only would risk damaging the old cable but also can be expected to be difficult, dangerous, and time consuming for a worker. Removal of the old hangers would require a worker to be suspended at varying and dangerous heights, where the worker would have to individually remove each old hanger, which over time may have become variously bent, rusted, corroded, etc. and therefore much more difficult to remove than when originally secured to the tower. Moreover, such retrofitting requires not only new hangers for the new cable(s) but also new replacement stackable hangers for the original cable so that, for example, adding one new cable would require sets of new cable hangers sufficient to hang two cables (the original cable and the new one). 
     Moreover, notwithstanding the prior stackable hangers such as mentioned herein, secure stacking of non-cylindrical longitudinal members such as waveguides has not heretofore been accomplished. 
     The present invention is directed toward overcoming one or more of the problems set forth above. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, an adapter is provided for use with a cable hanger, wherein the hanger includes a generally U-shaped member having a center portion and legs with a cable engaging section in each leg adapted to secure a cable to the legs, and the hanger further being adapted to attach cables to a tower leg. The adapter includes (1) a center platform defining an opening therein adapted to receive the legs of another cable hanger for securing the another cable hanger to the platform, (2) a pair of clamping members on opposite ends of the center platform with feet spaced from the center platform and directed toward each other, and (3) legs on opposite sides of the center platform and adapted to engage the cable hanger whereby the clamping member feet are held against the cable hanger center portion when mounted to the cable hanger. The clamping member feet are spaced apart less than the length of a cable hanger center portion, and the clamping members are elastically flexible to allow the feet to be separated sufficiently to clear opposite ends of a cable hanger center portion when mounting on the cable hanger. 
     In one form of this aspect of the present invention, the feet are tapered toward the center platform whereby pushing the adapter onto a cable hanger creates a force biasing the clamping members apart. 
     In another form of this aspect of the present invention, the center platform includes a recessed area extending between the platform ends, and the platform opening is in the recessed area. 
     In still another form of this aspect of the present invention, the platform is flexible for elastic bending around an axis extending between its ends. 
     In another aspect of the present invention, a mount is provided for hanging first and second cables on a structure. The mount includes a first cable hanger, an adapter and a second cable hanger. The first cable hanger includes a generally U-shaped member having a center portion and legs with a cable engaging section in each leg adapted to secure a first cable to the legs. The hanger being adapted to attach the first cable to a structure. The adapter includes a center platform defining an opening therein, a pair of clamping members on opposite ends of the center platform with feet on the clamping members spaced from the center platform and directed toward each other, and legs on opposite sides of the center platform. The clamping member feet are spaced apart less than the length of the center portion of the first cable hanger, and the clamping members are elastically flexible to allow the feet to be separated sufficiently to clear opposite ends of a cable hanger center portion when mounting on the first cable hanger. The adapter legs engage the first cable hanger to substantially secure the clamping member feet against the cable hanger center portion. The second cable hanger has two legs with the second cable secured between the legs and is secured to the adapter center platform with the second cable hanger legs secured in the adapter center platform opening. 
     In one form of this aspect of the present invention, the feet are tapered toward the center platform whereby pushing the adapter onto a cable hanger creates a force biasing the clamping members apart. 
     In another form of this aspect of the present invention, the center platform includes a recessed area extending between the platform ends, and the platform opening is in the recessed area. 
     In still another form of this aspect of the present invention, the platform is flexible for elastic bending around an axis extending between its ends. 
     In yet another form of this aspect of the present invention, the first cable hanger has an opening therein aligned with the adapter center platform opening, and the second cable hanger legs extend into the first cable hanger opening. 
     In a still further form of this aspect of the present invention, the structure is a tower leg. 
     In a further form of this aspect of the present invention, the first and second cables are first and second waveguides having a generally elliptical cross section and the legs of the first and second cable hangers are adapted to engage the longer sides of the first and second waveguides. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of two cable hangers stacked together using adapters according to the present invention, with two cables secured thereto; 
         FIG. 2  is a perspective exploded view showing assembly of a non-stackable cable hanger with an adapter according to the present invention; 
         FIGS. 3-5  sequentially illustrate from an end view the manner in which a cable hanger may be attached to an adapter and the manner in which another adapter may be attached to a cable hanger for further hanging; 
         FIG. 6  is an end view of  FIG. 1 ; and 
         FIG. 7  is a cross-sectional view taken along line  7 - 7  of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a pair of cables  10 ,  12  stacked together using a pair of cable hangers  16 ,  18  and a pair of adapters  22 ,  24  according to the present invention. 
     (As previously noted, as used herein, references herein to cable are meant to incorporate not only cables in the conventional sense but also other longitudinal members, such as waveguides, which may have a variety of cross-sectional shapes including elliptical, square, rectangular and round.) 
     It should be appreciated that the cable hangers  16 ,  18  may be of a prior art non-stackable configuration. As illustrated in phantom, the bottom cable hanger  16  may be suitably secured to a structure  30  such as a tower leg as illustrated, for example, in U.S. Pat. No. 5,976,468, the full disclosure of which is hereby incorporated by reference. Further, when hanging cables such as waveguides, the hangers may be of a configuration such as illustrated in U.S. Pat. No. 4,763,132, which hangers may, for example, be secured to a tower leg such as illustrated in that patent. The full disclosure of U.S. Pat. No. 4,763,132 is also hereby incorporated by reference. Again, it should be appreciated that while the description herein is made to hanging conventional long cylindrical cables, the present invention may also be used to significant advantage when hanging non-cylindrical longitudinal members such as waveguides. 
     It should be appreciated that the structure illustrated in  FIG. 1  could stack two cables  10 ,  12  without requiring the second adapter  24 . As illustrated with the second adapter  24 , a third cable hanger could be attached to the second hanger  18  and adapter  24  so that three cables could be mounted together. 
     The basic cable hanger  16  includes a generally U-shaped member  40  with a center portion  42  between a pair of legs  44 ,  46  defining a cable engaging section  48  and leg extensions  50 ,  52  which may be squeezed together to both squeeze the cable engaging section  48  around a cable  10 , as well as to permit the leg extensions to be moved through a suitable opening in the structure  30 . Locking members  54 ,  56  project outwardly from the leg extensions  50 ,  52  and snap out beneath the surface of the structure opening to retain the cable hanger in the opening. Supporting members  58 ,  60  are positioned to engage the outer surface of the structure  30  so that the leg extensions  50 ,  52  are biased slightly out of the structure opening to thereby pull the hanger  16  so that the locking members  54 ,  56  are held against inside surface of the structure opening whereby the cable hanger  16  is substantially fixed relative to the structure  30  without substantial wobble. 
     An advantageous adapter  22  according to the present invention is separately illustrated in the exploded view of  FIG. 2 . The adapter  22  includes a center platform  64  with an opening therein  66 . A pair of clamping members  70 ,  72  are on opposite ends of the center platform  64 , with the clamping members  70 ,  72  including feet  74 ,  76  spaced from the center platform  64  and directed toward each other. 
     As best seen in  FIG. 7 , the feet  74 ,  76  feet are spaced apart less than the length of the center portion  42  of the cable hanger  16 . Further, the feet  74 ,  76  are tapered toward the center platform  64 , and the clamping members  70 ,  72  are sufficiently elastically flexible to allow the feet  74 ,  76  to be separated enough to clear the ends of the cable hanger center portion  42  (i.e., the top and bottom in the  FIG. 7  view) during mounting on the cable hanger  16 . For example, if pushed straight on such as shown in  FIG. 2 , the taper of the feet  74 ,  76  will cause them to separate as they slide onto the ends of the hanger center portion  42  until they are sufficiently separated that they will pass over the center portion  42 . Once the feet  74 ,  76  pass over the center portion  42 , the clamping members  70 ,  72  will snap back together on the back side of the hanger center portion  42  to hold the adapter  22  on the hanger  16  (again, see  FIG. 7 ). 
     Alternatively, it should be appreciated that the adapter  22  could be mounted by first locating one of the feet  74  or  76  under one end of the hanger center portion  42  and then pushing the other end of the adapter  22  down until its foot  76  or  74  flexes out clear of the other end of the hanger center portion  42 , at which point that adapter end will move onto the hanger center portion  42  until that foot  76  or  74  can snap onto the underside of the center portion  42 . With this configuration, less flexing of the legs  70 ,  72  is required, enabling the adapter  22  to be more easily mounted onto the hanger  16  and/or for the clamping members  70 ,  72  to be formed more rigidly to improve strength without increasing the force required to mount the adapter  22  onto the hanger  16 . 
     Legs  80 ,  82  on opposite sides of the center platform  64  will at the same time engage the cable hanger  16  on its outer face, with the combined spring action of the legs  80 ,  82  on the outside of the hanger  16  and the feet  74 ,  76  on the inside of the hanger  16  will rigidly secure the adapter  22  to the hanger  16  such as can be seen in FIGS.  1  and  5 - 7 . 
     The center platform  64  of the adapter  22  may include a recessed area  86  between two raised areas  88  and extending between the ends of the center platform  64 , with the opening  66  being in the recessed area  86 . It should be appreciated that this configuration will provide a substantially advantageous rigid mounting platform for another hanger  18 , while at the same time providing flexibility for elastic bending around an axis extending between the adapter ends such as taught in U.S. Pat. No. 7,097,142 and as also discussed below. Cuts  90  on either side of the clamping members  70 ,  72  may also be provided to facilitate such flexibility of the center platform  64  on either side of the substantially inflexible bend connecting the clamping members  70 ,  72  and the central section of the recessed area  86 . 
     Specifically, it should be appreciated that a second cable hanger  18  can be stacked onto a non-stackable cable hanger  16  and adapter  22  in a manner similar to the way that cable hangers could be stacked onto stackable cable hangers such as U.S. Pat. No. 7,097,142. That is, the leg extensions  50 ,  52  of a hanger  18  can be squeezed together to pass through the opening  66  in the adapter center platform  64  and then released so that its locking members  54 ,  56  are retained on the back (underside) of the recessed area  86  (see  FIGS. 3-4 ). The supporting members  58 ,  60  engage the front (outer side) of the raised areas  88 . 
     Moreover, it should be appreciated that with the present invention, where the cable hanger  16  has an opening  92  in its center portion  42  as may be provided to both save materials and to provide the desired flexibility to the hanger  16 , the mounting of a second cable hanger  18  can be stronger and more reliable than even one piece stackable hangers such as used in the prior art. That is, with such an opening aligned beneath the opening  66  of the adapter center platform  64 . the leg extensions  50 ,  52  of the hanger  18  may extend not only through the adapter opening  66  but also through the hanger opening  92  as well, thereby providing two areas supporting the leg extensions  50 ,  52  at spaced apart locations to significantly enhance the rigidity of the mounting. 
     It should thus be appreciated that the present invention will allow stacking of hung cables even where non-stackable hangers have been used. Adapters incorporating the present invention will therefore allow advantageous stacking to occur on structures which have previously had one cable hung using non-stackable hangers without requiring that such hangers be removed and replaced, both of which are both costly and time consuming operations. Moreover, worker safety can be enhanced by requiring less work at dangerous heights on towers as well as making the work which is required simpler and more easily accomplished. Moreover, it should be appreciated that using adapters according to the present invention can provide improved hanging strength and reliability over hangers which have been intentionally designed for stacking. 
     It should further be appreciated that the present invention will advantageously allow waveguides to also be securely and reliably hung on a tower in a stacked configuration. 
     Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.