Abstract:
A cable holder for securing multiple elongated objects to a support has a plurality of inner and outer hangers fixedly attached to one another and each configured to receive a respective one of the multiple elongated objects. The inner and outer hangers are displaceable relative to one another so that the outer hanger does not block the inner hanger during attachment of the latter to a support.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to a cable holder configured to support one or more cables.  
       BACKGROUND OF THE INVENTION  
       [0002]     The use of transmission line or cable hangers, or clamps, configured to attach a transmission line or cable to a support, such as an antenna tower, have been known for many years. The advent of electronic equipment has caused a few problems related to coupling of a hugely increased number of transmission lines along antenna towers due to a limited space capable of accommodating these lines. Typically, since installation of cables is associated with safety considerations as well as with the time and expense involved with installing these lines, it is highly desirable to minimize both the amount of time and the complexity of the work required for coupling cables to support structures. To address these issues, various structures of cable hangers, designed to rapidly attach cables to support structures, have been recently developed.  
         [0003]     A typical cable holder is illustrated in  FIGS. 1 and 2  and includes inner and outer cable hangers  110  coupled to one another so that the outer hanger may be added later to accommodate additional cables without disassembling the previously installed hanger(s). Attachment of the inner hanger  110  to a support  118  as well as coupling the hangers to one another are realized by compressing opposite arms  112  so that locking fingers  114  are first inserted into an opening  116  and then, upon ceasing the compressing force, spread apart to reliably engage the rim of the opening. Support  118  may be horizontally or vertically disposed, and may include a plurality of openings to accommodate multiple hangers  110 .  
         [0004]     Insertion of the cable holder may pose several problems. For example, if the cable holder, as shown in  FIGS. 1 and 2 , is assembled before its attachment to the support  118 , the access to the inner hanger may be limited because the outer hanger blocks the inner one, which is, thus, difficult to reach manually. Note that the inner and outer hangers may rotate relative to one about an axis of symmetry S′-S′ upon insertion of the locking fingers  114  into the opening  116 . However, because this rotation occurs about the axis of symmetry common to both hangers, the outer hanger blocks the inner hanger regardless of the relative angular position of the hangers. Thus, this structure necessitates the use of instruments, which are a) inconvenient, since the direct access to the inner hanger is still blocked by the outer hanger, and b) undesirable, because having additional instruments on a tall tower imposes an additional physical and logistical hardship on the serviceman.  
         [0005]     If, however, the cable holder of  FIGS. 1 and 2  is deployed by initially attaching only the inner hanger with a respective cable to the support  118 , further installation of the outer hanger in response to the increased demands for additional cables may be associated with difficulties caused by climatic conditions. Indeed, typically, cables are installed on tall towers. As a consequence, low temperatures and strong winds may critically complicate the attachment of the outer hanger to the inner one. Also, gradual installation of subsequent outer hangers may be associated with still another problem stemming from variations of the size of the opening  116  leading to unreliable securing the hangers to one another and to the support  118 . Overall, the above-discussed problems may detrimentally affect the reliability of the installation as well as the safety of the worker.  
         [0006]     Furthermore, the cable holder of  FIGS. 1 and 2  is configured to lock a respective cable by compressing the arms of the hangers against this line upon inserting the locking fingers  114  into the opening  116 . Yet, the inherent elasticity of the arms of the hanger may not be sufficient to prevent displacement of the cables along the tower for a variety of reasons. Even those hanger designs that have mechanisms for penetrating or biting into the cable jacket may not prevent longitudinal movement of the cable because the frictional coefficient between the metal hanger and the plastic cable jacket is very low. The polyethylene typically used for cable jackets is a soft material that has an inherent lubricant quality. In addition, the cable jacket can “cold flow” which reduces the holding force of the cable hanger over time, resulting in cable slippage.  
         [0007]     It is therefore desirable to provide a stackable cable holder configured to provide an easy installment of cables as well as reliable securement thereof.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention attains these objectives by providing a stackable cable holder including multiple interconnected hangers, which are displaceable relative to one another without being detached. As a consequence, even if, initially, only a single cable, which is secured to an inner hanger, is needed, the installation of subsequent lines does not pose the difficulties associated with the discussed-above prior art, since an outer hanger, configured to receive an additional line, has been already installed.  
         [0009]     In accordance with one aspect of the invention, to facilitate access by the worker to an inner hanger couplable to a support, inner and outer hangers are displaceable relative to one another about an axis offset from a central symmetry axis. As opposed to the structure shown in  FIGS. 1 and 2 , displacement of the hangers about the off-center axis leads to a position in which the inner hanger can be conveniently gripped and squeezed by the worker. As a result, displacing the outer hanger relative to the inner one in accordance with the invention creates a sufficient space allowing the worker to manually attach the inner hanger to a support.  
         [0010]     In accordance with another aspect of the invention, the outer hanger is configured to positively lock a cable in the hanger. A locking assembly is characterized by its simplicity and is configured to allow reliable accommodation of differently sized cables.  
         [0011]     It is therefore an object of the invention to provide a cable holder overcoming drawbacks of the known prior art.  
         [0012]     A further object of the invention is to provide a cable holder allowing securement of additional cables in a time- and labor-efficient manner; and  
         [0013]     Still a further object of the invention is to provide a reliable securement of cables to the inventive cable holder. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The above and other features, objects and advantages will become more readily apparent from the detailed description of the invention accompanied by the following drawings, in which:  
         [0015]      FIG. 1  is an isometric view of detached inner and outer hangers of a stackable cable holder of the known prior art;  
         [0016]      FIG. 2  is an isometric view of the assembled cable holder of  FIG. 1 ;  
         [0017]      FIG. 3  is an isometric view of a stackable cable holder configured in accordance with the invention and shown in a deployed position, in which inner and outer hangers each are ready to receive a respective cable;  
         [0018]      FIG. 4  is an isometric view of a stackable cable holder configured in accordance with the invention and shown in an installation position, in which the outer hanger is displaced to allow substantially the unobstructed access to the inner hanger;  
         [0019]      FIG. 5  is an isometric view of the inner hanger of the inventive cable holder illustrating the interior surface of the outer hanger;  
         [0020]      FIG. 6  is an isometric view of the inner hanger of the inventive cable holder illustrating the exterior surface of the inner hanger;  
         [0021]      FIG. 7  is an isometric view of the outer hanger of the inventive cable holder illustrating the exterior surface of the outer hanger; and  
         [0022]      FIG. 8  is an isometric exploded view of the cable holder configured in accordance with another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0023]     Referring to  FIGS. 3-4 , the inventive cable holder  20  has at least one pair of coupled inner  22  and outer  24  hangers displaceable relative to one another along a direction “A”′ between deployed and installation positions as shown in  FIGS. 3 and 4 , respectively. In accordance with one inventive embodiment, the hangers  22 ,  24  rotate relative to one another about an axis C-C ( FIG. 4 ), which is offset from an axis of symmetry S-S ( FIG. 4 ) common to both hangers in the deployed position of  FIG. 3 . Accordingly, in the deployed position, the axis of symmetry S-S of both hangers  22 ,  24  extends substantially perpendicular to a longitudinal axis V-V of an antenna tower (not shown), which complicates access to a body  28  of the inner hanger  22  by a serviceman. To facilitate this access, the outer hanger  24  is designed to move so that the body  28  is conveniently exposed to the serviceman. The serviceman then applies a compressing force to the body  28 , brings the fingers  30  together to insert them into the support, which is not shown, but is similar to the one illustrated in  FIG. 2 . Upon ceasing the compressing force, the fingers are biased apart to have inner hook portions  34  ( FIG. 5 ) engage the rim of the opening  116 . To ensure that the inner hanger  22  would not disengage from the support  118 , the fingers  30  are formed with barbs  32  extending laterally outwards from the fingers to urge against the support upon ceasing the compressing force.  
         [0024]     Having installed the inventive cable holder  20  to the support, the outer hanger  24  is rotated to the deployed position of  FIG. 3 , in which the inner and outer hangers  22 ,  24  extend along longitudinal axis axes A-A and B-B parallel to the tower&#39;s longitudinal axis V-V. As a result, in addition to a cable locked in the inner hanger  22 , an additional cable can extend through and be locked in the outer hanger  24 , as will be disclosed below.  
         [0025]     Turning specifically to  FIGS. 5 and 6 , the inner hanger  22  is made preferably from a relatively flexible material, such as sheet steel, and includes the body  28  configured to have a substantially “C” shape particularly convenient for gripping by the serviceman. The body  28  extends between a bottom  36  and the recessed inner ends formed with multiple hook portions  34 , each pair of which defines therebetween a respective one of the fingers  30 .  
         [0026]     The bottom  36  of the body  28  is formed with a U-shaped or rectangular indent  37  interrupting an otherwise curved inner surface of the body  28  and extending outwards to support a pair of pins or rivets  42  and  42 ′, which are either fixed to the inner hanger  22  or removably attached thereto. The pin  42  extending through both the inner and outer hangers serves as the axis of rotation C-C of the hangers relative to one another. The other pin  42 ′ functions as an anchor frictionally engaging the outer hanger  24  in the deployed position of the holder  20 , as will be explained below. One of the reasons for forming the indent  37  is to allow the pins  42  and  42 ′ to have a sufficient length without excessively penetrating the space within the interior of the body  28 , which is configured to receive a cable, this preventing inadvertent damage to the cable.  
         [0027]     The outer side of the indent  37  serves as a support surface for the outer hanger  24  and carriers a plate  38  attached to this hanger by the pins  42  and  42 ′. To prevent displacement of the hangers beyond the deployed position of the cable holder  20 , the plate  38  is formed with a hook  40  configured to engage and subsequently stop the outer hanger  24  in the deployed position, as will be explained hereinbelow.  
         [0028]     As illustrated in  FIG. 7 , the outer hanger  24  is formed with a body having a pair of arms  26 , which, like the body  28  of the inner hanger, are made from flexible material to conform to variously dimensioned cables locked between the arms  26 . The arms  26  each have a respective outwardly concave region, configured to conform to an opposing segment of cable, and a pair of planar or inwardly convex inner  44 ,  48  and axially opposite outer free end regions  50 ,  52 . The inner regions  44 ,  48  are bridged to form a bottom  64  juxtaposed with the plate  38  and coupled thereto by the pin  42  so that the hangers  22 ,  24 , as discussed above, rotate relative to each other. The opposite outer free end regions  50 ,  52  are biased away from one another and capable of yielding to a compressing force applied by the serviceman after a respective cable is positioned between the concave portions of the arms  26 .  
         [0029]     In use, when the inner hanger  22  receives a respective cable, the serviceman applies a compressive force to the body  28  engaging thus the fingers  30  with the support. During the attachment of the inner hanger  22 , the outer hanger  24  is displaced to the installation position of  FIG. 4 , and, after the inner hanger has been mounted to the support, is rotated towards the deployed position about the pin  42 . As the outer hanger rotates, its bottom  64  engages the pin  42 ′ extending outwards from the plate  38  at a distance sufficient to prevent displacement of the outer hanger towards the deployed position unless a sufficient torque is applied thereto to overcome the pin&#39;s resistance. Having overcome this resistance, the bottom  64  of the outer hanger  24  continues to frictionally slide relative to the plate  38  until the pin  42 ′ snaps into an opening  66  ( FIG. 7 ) formed in the bottom  64 , preventing thus further displacement of the hangers. To ensure that the hangers are locked in the deployed position, the hook  40  of the plate  38  extends through and engages recesses  46  ( FIG. 7 ) of the inner end regions  44 ,  48  of the outer hanger  24 . Disengagement of the hangers  22 ,  24  is realized by initially applying a slight force directed so that the hangers are forced away from another along the axis of symmetry S-S ( FIG. 4 ), and subsequently, by applying a torque force to rotate to the installation position. While the plate  38  has been disclosed as attached to the inner hanger  22 , the inventive holder  20  can be easily modified so that the plate  38  is mounted to the outer hanger  24 .  
         [0030]     Locking of the cable in the outer hanger  24  can be realized by various means, one of which is illustrated in  FIGS. 3, 4  and  7  and includes multiple lugs  56 ,  58  and a locking member  54  engaging the lugs upon compressing the outer regions  50 ,  52  of the outer hanger. Structurally, the locking member  54  can be brought into engagement either with a pair of spaced apart side lugs  56  formed on the terminal portion of the end region  52  or the central lug  58  depending on a diameter of a cable. If this diameter is relatively small, the locking member  54  engages the central lug  58  spaced axially inwards from the side lugs  56  so that the inner surfaces of the concave portions of the arms  26  are compressed relatively close to one another to abut the received cable. However, if the cable to be locked has a relatively large diameter, the locking member will engage the pair of side lugs  56 . As can be seen in  FIG. 7 , the locking member  54  is configured as a frame rotatably mounted on the outer end region  50  of the outer hanger  24 . A specific shape and concrete dimensions of the locking member can be modified in response to the locking requirements.  
         [0031]     The hangers  22  and  24  are subject to substantial loads generated by the cables and, thus, should be sufficiently reinforced not to deform as a result of these loads. Accordingly many components of the hangers may be provided with reinforcing ribs, such a rib  60  formed on the arms  26  of the outer hanger  24 , as shown in  FIG. 7 .  
         [0032]     Turning to  FIG. 8 , a further embodiment of the invention, while utilizing the main concept including displacement of the hangers relative to one another, realizes this in a manner different from the embodiment shown in  FIGS. 3-7 . Instead of rotating about the rotation axis C-C ( FIG. 4 ), the cable holder of  FIG. 8  is characterized by linear motion of the inner  22  and outer  24  hangers relative to each other. In particular, one of the hangers, for example the inner hanger  22 , may be provided with an outwardly extending bottom portion  62  split in half and forming a recess  70  which is shaped and dimensioned to slidably receive a T-shaped flange  62 ′ configured complementary to the inner surface of the recess. In use, upon inserting the flange  62 ′ into the recess  70 , the hangers can slide relative to one another between the deployed position, in which the hangers coaxially extend along an axis of symmetry S″-S″, and the installation position, in which the outer hanger is displaced so that the body of the inner hanger is substantially unobstructed. The positions of the T-shaped flange  62 ′ and the bottom portion  62  can be reversed.  
         [0033]     It will be understood that various modifications may be made to the embodiments disclosed herein which can find a variety of applications expanding the scope of the invention beyond the disclosed coupling of cables. For example, the inventive holder can be utilized for installing elongated objects, such as pipes or tubes and a variety of transmission lines. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.