Abstract:
A coaxial cable extender having only two parts overcomes the complexity of prior devices while maintaining functionality. The extender includes a sleeve, attached to a conduit of the coaxial cable, having a ratchet toothed rack and a slider received on the sleeve. The slider has an integral arm with ratchet teeth biased against the ratchet toothed rack such that the slider may be ratcheted along the ratchet toothed rack to extend the effective length of the conduit.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to coaxial cable and, more particularly, to an extender for adjusting the effective length of the conduit of a coaxial cable.  
         BACKGROUND  
         [0002]    The use of coaxial cable for transferring motion from one location to another, remote, location is well known in the technology associated with bicycle braking and gearing systems as well as automobile throttle systems. The use of coaxial cable may be less well known, but just as functional, in other applications, such as the adjustment of various aspects of office chairs.  
           [0003]    The coaxial cable typically comprises only two parts, a cable and a conduit for the cable, although there may be assemblies of many more parts on the controlling and controlled ends of the coaxial cable.  
           [0004]    It has been recognized that the effective length of the conduit is important to the proper operation of the coaxial cable as a whole. With this in mind, several devices have been devised to adjust the effective length of the conduit. Example effective length adjusters include U.S. Pat. No. 4,694,706, issued Sep. 22, 1987 to Lichtenberg et al., U.S. Pat. No. 4,688,445, issued Aug. 25, 1987 to Spease et al. and U.S. Pat. No. 5,142,933, issued Sep. 1, 1992 to Kelley.  
           [0005]    In U.S. Pat. No. 4,694,706, a ratchet toothed rack is attached to the cable. A pawl with ratchet teeth engages the ratchet toothed rack to prevent longitudinal movement of the cable. The pawl may be rotated to a position wherein the ratchet teeth of the pawl no longer engage the ratchet toothed rack and the cable may be allowed to retract within the conduit. Although useful, the disclosed device requires the end of the cable to be fitted with the ratchet toothed rack. It may be that the end of the cable is to be used for a predetermined purpose that precludes use of this arrangement for adjusting the effective length of the conduit.  
           [0006]    In U.S. Pat. No. 4,688,445, a support member is attached to the conduit of the coaxial cable. The support member has a ratchet toothed rack. A slider member is received on the support member. The slider member has a ratchet toothed member biased against the ratchet toothed rack of the support member. A button is provided, the pressing of which temporarily overcomes the bias and disengages the ratchet toothed member of the slider member from the ratchet toothed rack of the support member. The disengagement allows the slider to be moved longitudinally along the support member.  
           [0007]    Similarly, in U.S. Pat. No. 5,142,933, a support member is attached to the conduit of the coaxial cable. The support member has a toothed rack. A slider member is received on the support member. The slider member has a toothed member biased against the toothed rack of the support member. Movement of a lever into a particular position disengages the toothed member of the slider member from the toothed rack of the support member, thus allowing the slider member to be moved longitudinally along the support member.  
           [0008]    In both of the latter two patents discussed hereinbefore, the slider member is a complex arrangement of parts including a biasing member, a locking member and a means to move the locking member from an engaged position to a disengaged position.  
           [0009]    Clearly, a coaxial cable conduit extender is required whose design is simple, whose number of components is minimized and that does not have a requirement that the end of the cable be altered.  
         SUMMARY  
         [0010]    A coaxial cable extender having only two parts overcomes the complexity of prior devices while maintaining functionality. In particular, the parts include a sleeve, attached to the coaxial conduit to be extended, and a conduit extending slider received on the sleeve. The slider is normally prevented from sliding along the sleeve, in the direction that would reduce the effective length of the conduit, by a ratchet mechanism. On the other hand, the ratchet mechanism allows the slider to slide along the sleeve in the direction that would extend the effective length of the conduit.  
           [0011]    In accordance with an aspect of the present invention there is provided an extender for a conduit of a coaxial cable. The extender includes a first member adapted to be attached to the conduit, the first member having a ratchet toothed rack, and a slider having an integral arm, the integral arm having ratchet teeth adapted to be biased against the ratchet toothed rack such that the slider may be ratcheted along the ratchet toothed rack to extend an effective length of the conduit.  
           [0012]    In accordance with another aspect of the present invention there is provided an extender for a conduit of a coaxial cable. The extender includes a first member attached to the conduit, the first member having a ratchet toothed rack, and a slider having an integral arm, the integral arm having ratchet teeth biased against the ratchet toothed rack such that the slider may be ratcheted along the ratchet toothed rack to extend an effective length of the conduit.  
           [0013]    Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    In the figures which illustrate example embodiments of this invention:  
         [0015]    [0015]FIG. 1 is a side view of the coaxial cable and a conduit extender according to an embodiment of the present invention;  
         [0016]    [0016]FIG. 2 is a top view of the conduit extender of FIG. 1;  
         [0017]    [0017]FIG. 3 is a sectional view taken substantially along line  3 - 3  of FIG. 2;  
         [0018]    [0018]FIG. 3A is an exploded view of FIG. 3;  
         [0019]    [0019]FIG. 4 is a sectional view taken substantially along line  4 - 4  of FIG. 2; and  
         [0020]    [0020]FIG. 5 is a sectional view taken substantially along line  5 - 5  of FIG. 2.  
     
    
     DETAILED DESCRIPTION  
       [0021]    [0021]FIG. 1 illustrates a coaxial cable including a cable  116  and a conduit  102  through which the cable  116  may be longitudinally moved. The cable  116  is shown to extend through an end member  118 , which attaches to the conduit  102  at one end. The end member  118  includes a circumferential groove  120  for facilitating attachment of the end member  118  to a part of the device that is to be controlled by the coaxial cable. As is conventional, a terminator  114  may be found at each end of the cable  116 .  
         [0022]    At the other end of the coaxial cable (opposite the end to which the end member  118  is attached) is a conduit extender, generally indicated as  100 . The conduit extender  100  includes two parts, namely a sleeve member  104  and a slider member  106 .  
         [0023]    The sleeve member  104  has an end portion  305  press fit around one end of the conduit  102 . The sleeve member  104  defines a cable channel  402  through which the cable  116  may pass from a first end  304  to a second end  310  of the sleeve member  104 . Integral to the sleeve member  104  is an outward facing ratchet toothed rack  112  toward the second end  310  of the sleeve member  104 .  
         [0024]    The slider member  106  has a body portion  122  defining a large passageway  308  (see FIG. 3) and a neck portion  124  defining a small passageway  306 . The body portion  122  of the slider member  106  also defines a window  202  (see FIG. 2) into the large passageway  308 . The slider member  106  includes an integral arm  108  extending from the neck portion  124  of the slider member  106 . The slider member  106 , including the integral arm  108 , may be fabricated of a modestly resilient material such as fiberglass-reinforced nylon, although there are many other suitable materials. The integral arm  108 , when relaxed, extends into the window  202 . The integral arm  108  has a set of inward facing ratchet teeth  110  sized to engage with the ratchet toothed rack  112  of the sleeve member  104 .  
         [0025]    For ease of installing the slider member  106  over the sleeve member  104  with a portion of the cable  116  extending therefrom, an opening  302  is provided at a transition between the body  122  and the neck  124  of the slider member  106 . The opening  302  allows the terminator  114  at the end of the cable  116  to bypass the small passageway  306 . The sectional view of FIG. 5 illustrates, in cross-section, the small passageway  306  in the neck portion  124  of the slider member  106 .  
         [0026]    A ridge  404  (FIG. 4) extends from the body portion  122  into the large passageway  308  of the slider member  106 .  
         [0027]    The neck portion  124  has a circumferential groove  126  for facilitating attachment of the slider member  106  to a part of the device that is to be controlled by the coaxial cable.  
         [0028]    The free end of the integral arm  108  may be provided with a shape and dimension that permits the integral arm  108  to be manually pulled away from the body portion  122 . An exemplary shape is a fluke shape, as illustrated in FIG. 2. A cross-section of the fluke shape of the integral arm  108  is illustrated in FIG. 4, wherein two wings  406  may be identified.  
         [0029]    The large passageway  308  of the slider member  106  allows the second end  310  of the sleeve member  104  to be received by the slider member  106 . The small passageway  306  of the slider member  106  allows the passage of the cable  116 . Once the sleeve member  104  has been received by the large passageway  308  of the slider member  106 , the window  202  in the body portion  122  of the slider member  106  allows the ratchet teeth  110  of the integral arm  108  of the slider member  106  to contact the ratchet toothed rack  112  of the sleeve member  104 .  
         [0030]    In overview, the conduit extender  100  may be used to adjust the effective length of the conduit  102  of a coaxial cable.  
         [0031]    In operation, the ratchet teeth  110  of the integral arm  108  the slider member  106  are biased, through the window  202  in the slider member  106 , against the ratchet toothed rack  112  of the sleeve member  104  by virtue of the resilient material of which the slider member  106  is constructed. While biased against the ratchet toothed rack  112 , the ratchet teeth  110  of the integral arm  108  allow the slider member  106  to be moved in a direction (to the right, as illustrated in FIG. 1) to increase the effective length of the conduit  102 . At the same time, movement in a direction (to the left, as illustrated in FIG. 1) to decrease the effective length of the conduit  102 , is prevented by engagement between the ratchet teeth  110  of the integral arm  108  and the ratchet toothed rack  112  of the sleeve member  104 .  
         [0032]    To shorten the conduit extender  100 , thereby reducing the effective length of the conduit  102 , it is required that the integral arm  108  be lifted (i.e., pulled away from the body portion  122 ), overcoming the force biasing the ratchet teeth  110  of the integral arm  108  against the ratchet toothed rack  112  of the sleeve member  104 , such that the ratchet teeth  110  disengage the ratchet toothed rack  112 . The lifting of the integral arm  108  may be performed many ways including manually or through a mechanical linkage. The fluke shape, illustrated in FIG. 2, facilitates a manual lifting of the integral arm  108 .  
         [0033]    The ridge  404 , which extends into the large passageway  308  of the slider member  106 , cooperates with the walls of the cable channel  402  of the sleeve member  104  to prevent rotational movement of the slider member  106  about the sleeve member  104 . Such rotational movement might, if it were allowed to happen, allow the ratchet teeth  110  to disengage from the ratchet toothed rack  112  unintentionally. Although the ridge  404  suitably prevents rotational movement of the slider member  106  about the sleeve member  104 , alternatives are available. For instance, if the sleeve member  104  was of a rectangular cross-section and the large passageway of the slider member  106  was of a parallel shape to receive the rectangular sleeve member, rotation would be avoided.  
         [0034]    Advantageously, the conduit extender  100  may be retrofit to existing coaxial cables. The conduit extender  100  may, for instance, replace an existing conduit extender. To install the conduit extender  100 , the cable  116  is inserted along the cable channel  402  of the sleeve member  104 . The end portion  305  of the sleeve member  104  is then press fit around the end of the conduit  102 . The sleeve member  104 , with a portion of the cable  116  extending therefrom, may then be inserted into the large passageway  308  of the slider member  106 . As the sleeve member  104  is inserted into the large passageway  308 , the extending portion of the cable  116  may be directed to pass through the opening  302 . The opening  302  is provided in anticipation of the fact that the terminator  114  is too large to pass through the small passageway  306  in the neck portion  124 . Consequently, where the terminator  114  is small enough to pass through the small passageway  306  in the neck portion  124 , the opening  302  may not be required. The extending portion of the cable  116  may then be inserted along the small passageway  306 .  
         [0035]    The ratchet teeth  110  and the teeth of the ratchet toothed rack  112  are shown to be right angle triangular. It should be apparent to a person skilled in the art that many tooth shapes exists that serve the same engaging function. Additionally, the teeth of the ratchet toothed rack  112  need not be identical to the ratchet teeth  110 . Indeed, while one may define a specific tooth shape, the other may define indentations that receive the specific tooth shape.  
         [0036]    Additionally, many different shapes may be available for the integral arm  108 . For instance, rather than wings  406  on the sides of the integral arm  108 , a loop may be provided on the top of the integral arm  108 , where the loop is sized to allow a finger to be inserted to lift the integral arm  108  such that the ratchet teeth  110  disengage the ratchet toothed rack  112 .  
         [0037]    As will be apparent to a person skilled in the art, the ratchet toothed rack  112  need not necessarily be integral with a sleeve member. Instead, a stand-alone ratchet toothed rack may be attached to the conduit  102 . Such an arrangement would require that the large passageway of the slider member be sized to receive the conduit  102  in conjunction with the stand-alone ratchet toothed rack. Operation of such an arrangement, however, would not differ significantly from that described hereinbefore. That is, the ratchet teeth  110  of the integral arm  108  would contact the stand-alone ratchet toothed rack through the window  202  in the slider member  106 . It is also contemplated that an especially long integral arm could be arranged to reach beyond the sleeve or conduit receiving end to engage a ratchet toothed rack, thus dispersing with the need for the window  202 .  
         [0038]    In an alternative embodiment, the slider member  106  is not fabricated entirely of resilient material. Instead, the slider member  106  is primarily fabricated of non-resilient material and resilience is provided only in the fabrication of the integral arm  108  or only at the base of the integral arm  108 .  
         [0039]    Other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.