Abstract:
An aerial cable spacer is provided with a cable retainer and vertically disposed strengthening tabs or ribs. The cable retainer includes a cable retaining arm. A mid portion of the cable retaining arm has a non-rectangular plus “+” shaped cross section. The plus “+” shaped cross section engages and exerts a force on the cable as the cable retaining arm bends to a closed position. The arm is flexible so as to create a resilient force in conjunction with the plus “+” shaped cross section to securely hold the cable on a cable seat of a main body portion of the aerial cable spacer. A pawl is carried on the arm at a predetermined orientation to engage a corresponding set of teeth on the spacer body for enhanced cable clamping force.

Description:
FIELD OF THE INVENTION 
       [0001]    The present application relates to apparatus for supporting one or more cables above the ground, and more particularly to an aerial cable spacer apparatus and to a cable retainer for use with aerial cable spacers, the cable retainer including a latching cable retaining arm with a non-rectangular, preferably plus (“+”) shaped, cross section providing improved clamping capability for holding associated cables on the spacer body. The arm further includes an engagement pawl carried on the arm at a preselected angle for improved cable holding strength. 
       BACKGROUND 
       [0002]    The present exemplary embodiments relate to spacers for aerial cables and to cable retainers for holding the cables relative to the spacers. They find application in conjunction with spacers for power distribution cables, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiments are also amenable to other like applications including anywhere elongate objects are to be held in a spaced apart relationship. 
         [0003]    Overhead utility cables are commonly suspended from a messenger cable typically made of a high strength metal alloy. The messenger cables are strung between spaced apart towers, utility poles, and the like throughout various areas for purposes of supporting utility cables such as power distribution cables into those areas. In typical large scale applications, three phase power is distributed into residential or commercial areas. One example is 15 kv three phase power carried on three separate conductors and distributed into the service area suspended under messenger cables supported on poles or towers in the manner described above. 
         [0004]    It is to be appreciated that current carrying conductors should not be permitted to come into contact with each other. Insulation on jacketed conductors can be worn away and, of course, contact between uninsulated conductors would result in a short circuit fault in the grid system. Therefore, typically, the power conductors are carried below the messenger cable by an aerial cable spacer device. A primary function of the spacer is to suspend the power cables from the messenger cable and carry the cables throughout the service area. Another function of the spacer device is to establish and maintain a predefined distance between the power conductors for various reasons such as, for example, to control system characteristics including material reactive impedance characteristics. 
         [0005]    One prior art aerial cable retainer device is shown in U.S. Pat. No. 4,020,277 which shows a basic spacer for supporting a set of three electrical conductor cables above the ground. The spacer taught there includes a body member having four concave seats including one downwardly oriented seat adapted to receive a messenger cable and three upwardly oriented seats adapted to receive as many power conductor cables. Each of the concave seats is associated with at least one generally arcuate cable retaining arm for engaging a surface of the conductor cable and messenger cable and holding them in their respective seats. One end of each of the cable retaining means is pivotally connect with the body member and ratchet tooth means in the form of a pawl is provided on the other free end of the cable retaining arm. A set of ratchet tooth means are also provided on the spacer body member outwardly of the concave seats and are generally arranged in the shape of an arc. The teeth of the retainer arms are engageable with the teeth of the body member ratchet tooth means when the retaining arms are rotated about their pivotal supports thereby to hold the conductor cables and messenger cable in their respective concave seats. It has been found at times, however, that the prior art spacers of this type experience a less than desirable force exerted against the cables held in their respective concave seats. In addition, in the prior devices, it was difficult to close the cable retainer with sufficient force exerted on the cable. 
         [0006]    U.S. Pat. No. 6,047,930 teaches a cable retaining arm in a spacer for aerial cables of the type described in the &#39;277 patent but includes an additional fulcrum point carried on the arm. The fulcrum point engages and exerts a force on the cable as the cable retaining arm bends to a closed position. However, the cable retaining arm taught in the &#39;930 patent is difficult to manufacture, adds cost to the device due to the additional materials needed to form the fulcrum point, and presents potential inherent stress and fracture areas adjacent either side of the fulcrum point section as the cable retaining arm is biased into position across the respective cable. 
         [0007]    U.S. Pat. No. 6,170,783 proposes a further modification to a cable retaining arm in a spacer for aerial cables of the type described in the &#39;277 patent. In the &#39;783 patent, a resilient pad is secured to either or both of the cable seat on the spacer main body member as well as on the cable retaining arm. When a cable is located in the cable seat and the cable retaining arm is closed upon the cable, the resilient pad is compressed and is said to act like a spring to maintain a force on the cable. The resilient pad concept applied to the cable retaining arms of a spacer for aerial cables as proposed in the &#39;783 patent adds further complexity and cost to the product and, it is believed, invites mechanical failure in the arm in the high-stress regions adjacent either side of the resilient pad. 
         [0008]    Lastly, U.S. Pat. No. 6,303,856 proposes various means for providing an anti-dislodging cable retainer in a cable spacer device of the type taught in the &#39;277 patent. In the &#39;856 patent, either a slot or a groove are formed on respective opposite ones of the cable retaining arm and the cable seat on the body member for establishing a mechanical interlock between a ratchet tooth carried on the cable retaining arm and a plurality of spaced apart ratchet teeth formed on the spacer body member. The abutment surfaces described in the &#39;856 patent introduce manufacturing burdens and complexities in the final product. 
         [0009]    Thus, there is a need in the art for improved aerial cable spacers which are easy to manufacture and use and for cable retaining arms with enhanced clamping and cable holding capabilities for connecting associated cables with cable spacer bodies of aerial cable spacers. 
       BRIEF DESCRIPTION 
       [0010]    The present application is directed to aerial cable spacers and to cable retaining arms which overcome the above noted and other problems found in the prior art. 
         [0011]    In a first embodiment, an aerial cable spacer includes a main body portion and a cable retaining arm. The main body portion has a cable seat with a cable engaging surface, a first side adjacent the cable seat, and second side adjacent the cable seat and opposite from the first side. The cable retaining arm has a first end pivotally connected to the second side adjacent to the cable seat, a second end releasably engageable with the first side adjacent to the cable seat, and a mid portion having a non-rectangular shaped cross section whereby the cable retaining arm is configured to close upon a cable positioned on the cable seat and flex so as to create a resilient force in conjunction with the non-rectangular cross section to securely hold the cable on the cable seat of the main body portion. 
         [0012]    In accordance with another aspect of the application, the mid portion of the cable retaining arm has a plus (“+”) shaped cross section. 
         [0013]    In accordance with yet a further aspect of the application, the mid portion of the cable retaining arm has an oval shaped cross section. 
         [0014]    Still further, in accordance with yet another aspect of the application, the cable retaining arm has first and second parallel arms, each arm having a first end pivotally connected to the second side adjacent to the cable seat, a second end releasably engageable with the first side adjacent to the cable seat, and a mid portion having a non-rectangular shaped cross section whereby the cable retaining arm is configured to close upon a cable positioned on the cable seat and flex so as to create a resilient force in conjunction with the non-rectangular cross section of the arms to securely hold the cable on the cable seat of the main body portion. 
         [0015]    In accordance with yet a further aspect of the application, the mid portion of each of the first and second parallel arms of the cable retaining arm has a plus (“+”) shaped cross section. 
         [0016]    In accordance with yet a still further aspect of the application, the mid portion of each of the first and second parallel arms of the cable retaining arms has an oval shaped cross section. 
         [0017]    Still further, the subject aerial cable spacer includes a first set of ratchet teeth at the first side of the main body portion and a second set of ratchet teeth on the second end of the cable retaining arm, the first and second set of ratchet teeth being mutually releasable. 
         [0018]    Still further, in accordance with yet another aspect, the second set of ratchet teeth include a single pawl carried at the second end of the cable retaining arm and oriented at a predetermined angle to releasably engage the first set of ratchet teeth on the first side of the main body portion. 
         [0019]    Still further, in accordance with yet a further aspect of the present application, the mid portion of the cable retaining arm has an outer surface and an inner surface facing the cable seat and adapted to engage an associated cable positioned on the cable seat when the retaining arm is closed on the cable. The pawl is oriented to generally extend from the second end of the cable retaining arm towards the first end of the cable retaining arm and from the outer surface towards the inner surface. In their preferred form, the first set of ratchet teeth at the first side of the main body portion are provided to define a curved line arranged to generally approximate a circle having a center located on the main body portion. The pawl carried at the second end of the cable retaining arm is selectively received in the first set of ratchet teeth at an angle of about 30 degrees at an initial clamping position to an angle of about 60 degrees at a final clamping position relative to a line tangent to said circle. The range of engagement angles is advantageously enabled by the curved line (non-circular) arrangement of ratchet teeth on the spacer body. 
         [0020]    These and other aspects of the subject application will be described in greater detail below with reference to the drawing figures. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is an elevational view of a cable spacer in accordance with a preferred embodiment showing each of the cable retaining arms in an engaged position relative to the spacer body and with two of the arms adapted to receive power conductor cables, one of the arms adapted to receive a messenger cable, and the last arm being disposed in a fully closed position; 
           [0022]      FIG. 2  is a side elevational view looking from the left to right at the spacer of  FIG. 1 ; 
           [0023]      FIG. 3  is a perspective view of the spacer of  FIG. 1  rotated slightly clockwise, forward, and to the left; 
           [0024]      FIG. 4  is a perspective view of one of the retaining arms of the spacer of  FIGS. 1-3 ; 
           [0025]      FIG. 5  is an enlarged top plan view of one of the cable retaining arm shown in  FIG. 4 ; 
           [0026]      FIG. 6  is a side elevational view of the retaining arm of  FIG. 5  from line  6 - 6 ; 
           [0027]      FIG. 7  is a sectional view taken on line  7 - 7  of  FIG. 5 ; 
           [0028]      FIG. 8  is an enlarged sectional view taken at line  8 - 8  of  FIG. 5 ; and, 
           [0029]      FIG. 9  is an enlarged elevational view of a conductor seat of the spacer with a major portion of the body of the spacer being broken away. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    With reference now to the drawings wherein the showings are for purposes of illustrating the preferred embodiments of the invention only and not for purposes of limiting same,  FIG. 1  shows an aerial cable spacer  10  including a main body member  12  and a set of generally arcuate cable retaining arms  14 ,  16 ,  18 , and  20 , each having a first end  14 ′,  16 ′,  18 ′, and  20 ′ pivotally connected with the main body member  12 , a second end  14 ″,  16 ″,  18 ″, and  20 ″ releasably engageable with the main body member  12  in a manner to be described below, and a flexible mid portion  14 ″,  16 ″,  18 ″, and  20 ″. In their preferred form, each of the cable retaining arms  14 - 20  are identical. In addition, both the body member and the retaining arms are made from the same thermoplastic material, preferably a resilient high-density polyethylene which has a low dielectric constant with good weather, UV, and strength characteristics. The cable retaining arms are molded separately from the body and attached thereto using a simple snap fit operation as will become apparent in the description below. 
         [0031]    Overall, the main body member  12  and the cable retaining arms  14 - 20  define a set of cable retaining means  22 ,  24 ,  26 , and  28  adapted for holding associated cables in place relative to the subject spacer  10 . Preferably, the first and third cable retaining means  22  and  26  are formed on opposite sides of a virtual center point  30  of the main body member  12 . Similarly, the second and fourth cable retaining means  24 ,  28  are formed on opposite sides of the virtual center point  30 . In the preferred form of the subject axial cable spacer  10 , each of the cable retaining means  22 - 28  are circumferentially spaced apart evenly about an imaginary circle lying in plane defined by the main body member and centered on the virtual center point  30 . 
         [0032]    As best shown in  FIGS. 1 and 3 , the cable retaining means are configured for holding cables relative to the body portion. Particularly, the first cable retaining means  22  is adapted to receive an associated messenger cable (not shown) while the remaining cable retaining means  24 - 28  are adapted to receive associated power conducting cables (not shown). Those skilled in the art would appreciate that the first cable retaining means  22  has slightly smaller dimensions than the other cable retaining means  24 ,  26 , and  28  because power conducting cables are typically larger than the messenger cables used to suspend the spacer and the power cables. 
         [0033]    The first cable retaining means  22  is comprised of the first cable retaining arm  14  and a first cable retention area  32  formed by the main body member  12 . Preferably, the first cable retention area  32  has a size and shape adapted to receive a messenger cable therein. The second, third, and fourth cable retaining means  22 ,  26 , and  28  are comprised of, respectively, cable retaining arms  16 ,  18 , and  20  together with second, third, and fourth cable retention areas  34 ,  36 , and  38  defined by the main body member. As can be seen from the drawing figures, each of the second, third, and fourth cable retention areas  34 ,  36 , and  38  are identically formed in order to receive a set of like-sized power conducting cables forming a conductor set as understood by those skilled in the art. 
         [0034]    Each of the cable retention areas  32 ,  34 ,  36 , and  38  include a corresponding generally concave cable seat  42 ,  44 ,  46 , and  48  defined by the main body member  12 . As noted above and shown in the figures, each of the cable seats  44 ,  46 , and  48  are substantially identical and the other cable seat  42  is similar but smaller. Each of the cable seats  42 ,  44 ,  46 , and  48  defines a corresDondina cable engaging surface  43 ,  45 ,  47 , and  49 , resDectively between opposite first  42 ′,  44 ′,  46 ′, and  48 ′ and second  42 ″,  44 ″,  46 ″, and  48 ″ sides. 
         [0035]    The main body member  12  is further provided with four generally arcuate ratchet tooth means  52 ,  54 ,  56 , and  58  located outwardly from the concave cable seats  42 , 44 ,  46 , and  48 . In their preferred form, the ratchet tooth means  52 ,  54 ,  56 , and  58  define a curved surface or line to generally approximate a circle. Still further, each of the cable retention areas includes a semi-cylindrical socket  62 ,  64 ,  66 , and  68  which are located adjacent to the sides of the cable seats  42 ,  44 ,  46 , and  48 , respectively. Further, each of the sockets  62 ,  64 ,  66 , and  68  are located adjacent to the sides of the cable seats  42 ,  44 ,  46 , and  48  which are opposite to the sides of the seats on which the body ratchet tooth means  52 ,  54 ,  56 , and  58  are disposed. Each of the sockets are provided with slots  62   a,    64   a,    66   a,  and  68   a  which are formed in part between opposed flanges forming the socket and integral with the main body member  12 . The slots enable the cable retaining arm to be assembled onto the main body member by snap fitting a portion of each arm into a respective socket through the slot. 
         [0036]    As noted above, each of the cable retaining means  22 ,  24 ,  26 , and  28  includes a cable retaining arm  14 ,  16 ,  18 , and  20  pivotally connected with the main body member  12  and preferably at each of the semi-cylindrical sockets  62 ,  64 ,  66 , and  68 , respectively. In the preferred form of the subject cable spacer  10 , each of the cable retaining arms are identically formed and, therefore, the description of the first cable retaining arm  14  which follows below applies equally to each of the second, third, and fourth cable retaining arm  16 ,  18 , and  20 . 
         [0037]      FIGS. 4-8  best show the details of the cable retaining arm  14  forming cable retaining means  22  of the subject cable spacer  10 . In their preferred form, each cable retaining arm  14  comprises a pair of spaced generally arcuate arms  70 ,  72  ( FIGS. 4 and 6 ), connected together at a first end  14   a  by a generally cylindrical member  74  and at the other or second end  14   b  by a transverse member  76 . The transverse member  76  is provided with a hole or perforation  78  adapted to receive an associated installation tool (not shown) for installing the cable retaining arm  14  onto the associated cable retention area of the main body member. In addition, the transverse member  76  of each of the cable retaining arms is provided with an engagement pawl  77  adapted to engage the ratchet tool means  52  formed by the main body member. 
         [0038]      FIGS. 6 and 7  show the preferred arcuate shape of each of the cable retaining arms of the subject cable spacer. As shown there, the cable retaining arm  14  has a preferred U-shaped conformation defined by a pair of spaced apart sharp curved regions  80  and  82  located between a connection end  84  and a free end  86  of the arm  14 . As described above, the connection end  84  of the arm is substantially defined by the cylindrical member  74  and, therefore, is adapted for connection onto the socket  62  defined in the main body member  12 . In its preferred form, the cylindrical member  74  is slightly larger than the sockets formed by the main body member. In that way, the arm is engaged more tightly with the body thereby increasing stiffness and decreasing the amount of play that the arm may have. The free end  86  of the retaining arm  14  includes the transverse member  76  provided for adapting the arm for connection with an associated tool (not shown). In its preferred from, the cable retaining arm includes a first substantially linear region  90  defined between the connection end  84  and the first sharp curved region  80 . Similarly, a second linear region  92  is defined between the first and second sharp curved regions  80 ,  82 . Lastly, a third linear region  94  is defined between the second sharp curved region  82  and the free end  86  of the cable retaining arm  14 . 
         [0039]    Preferably, the angle defined between the first and second linear regions is approximately 120 degrees and the angle between the second and third linear regions is about 120 degrees. One advantage of a cable retaining arm having spaced apart arcuate curved arms  70 ,  72  having a profile as shown in  FIGS. 6 and 7  described above includes additional clamping force exerted on the cable installed on the subject spacer. The curved profile of the arms  70 ,  72  provides an “over-center” type connection of the arm relative to the cable retention areas when the pawl  77  is engaged with the ratchet tooth means  52  of the cable retention area. 
         [0040]    In addition to the above, preferably, each of the arms  70 ,  72  has a non-rectangular cross section to provide enhanced clamping forces. More particularly,  FIG. 8  is a cross-sectional view taken along line  8 - 8  of  FIG. 5 . As shown there, each of the pair of spaced apart generally arcuate arms  70 ,  72  has a non-rectangular cross section  100 ,  102  as shown. Preferably, the arms have a plus (“+”) shape  104 ,  106  as shown. However, it is to be appreciated that other non-rectangular cross sectional shapes can be used as well such as, including oval, an irregular shape or any other structural shape for example as desired. 
         [0041]    Each of the cable retaining arms  14 - 20  are assembled onto the main body member  12  by simply inserting the cylindrical members  74  of the retaining arms into respective ones of the sockets  62 - 68  formed at each of the cable retention areas  32 - 38 . In its preferred form, the socket is formed of a resilient thermoplastic material so that the cylindrical member is tightly received therein in order to slightly hold the cylindrical member and, thus, the retaining arm in place relative to the main body member. Preferably, only a small amount of force is required to move the retaining arm from its clamped position so that the arm can be rotated about the socket and cylindrical member whereby the central curved portions  80 ,  82  and the second linear region  92  can be brought into contact with the outer peripheries of the conductor cables disposed in the cable seat portion of the cable retention area. The pawl  77  of the cable retaining arm  14 - 20  defines a circular path upon rotation of the arm about the socket. 
         [0042]    As shown in  FIG. 9 , the planes of the tooth means  58  intersect each other at a line A on the body member which is above and spaced upwardly of the axis B of the socket  68 . Accordingly, when pressure is exerted upon the teeth of the retaining arm, the pawl tends to lock the retaining means in the closed position. 
         [0043]      FIGS. 4 ,  6 , and  7  best illustrate the preferred formation of the pawl member  77  carried on the cable retaining arms in the subject cable spacer  10 . As illustrated, each of the cable retaining arms includes an outer surface  100 , and an inner surface  102 . The inner surface  102  is oriented in a direction to engage an associated cable member retained in the cable retention areas formed by the subject main body member. The outer and inner surfaces defined by the third linear region  94  of each of the cable retaining arms are on opposite sides thereof.  FIGS. 6 and 7  illustrate the preferred orientation of the pawl  77  relative to the outer and inner surfaces  100 ,  102  of the retaining arm. More particularly, the pawl  77  is preferably oriented from the outer surface  100  toward the inner surface  102  of the cable retaining arm in the third linear region  94  thereof. In addition, as is clear from the drawing figures, the pawl  77  extends from the free end  86  of the cable retaining arm toward the connection end  84  thereof. Overall, therefore, in its preferred form, the pawl  77  is carried on each retaining arm and extends therefrom in a direction extending from the outer surface  100  toward the inner surface  102  and from the free end  86  toward the connection end  84  thereof. 
         [0044]      FIG. 9  shows the preferred engagement angle D of about 45 degrees of the pawl when the arm (not shown) is received onto the main body member at a midway clamped position with the pawl engaged into the ratchet teeth  58  of the main body member. The preferred angle D 1  illustrated is about 45 degrees relative to a line L tangent to the arc C forming an imaginary circle centered about the axis B described above. It is to be appreciated that the ratchet teeth  58  lie on a curved non-circular line and, therefore, the pawl engages the teeth at an angle D 2  of about 30 degrees in an initial clamping position of the retaining arm (not shown) to an angle D 3  of about 60 degrees at a final clamping position. The curved line C defined by the ratchet teeth  58  are arranged to approximate a circle having a midpoint B which is offset from a pivot center of the retaining arm portion. 
         [0045]    The configuration and orientation of the pawl  77  relative to the ratchet tooth means  58  formed on the main body member in accordance with the preferred embodiment of the subject axial cable spacer ensures that the retaining arms are held in a closed position thereby clamping the associated cable onto the main body member with an enhanced force over prior art methods and devices. 
         [0046]    The exemplary embodiments have been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.