Abstract:
The present invention is a speed control for a cable retractor. The cable retractor with which the speed control is used comprises a pulley that engages a cable that may be extended and retracted. A friction element configured to adjustably contact the cable adjacent to the pulley is attached to a movable linkage. The movement of the linkage is constrained to move along a predetermined path such that movement of the linkage along the path alters the distance between the friction element and the pulley. In one or more embodiments a cantilevered spring is attached to the linkage. An adjustable control, for example a thumbscrew, is configured to move the spring in relation to the linkage in a manner that alters the position of the friction element with respect to the cable and/or the pressure exerted by the friction element on the cable.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is a continuation-in-part of U.S. patent application Ser. No. 12/795,611 filed Jun. 7, 2010, which claims the benefit of the filing date of U.S. Provisional Patent Application No. 61/186,346 filed Jun. 11, 2009, both of which are incorporated by reference in their entirety herein. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates generally to mechanical apparatus for management of electrical cabling and, more specifically, to an adjustable speed control for a cable retractor that facilitates the controlled extension and retraction of cabling. 
     (2) Description of the Related Art 
     Electronic equipment is typically interconnected by cables. Cables are often equipped with connectors that allow their connection to and disconnection from equipment. When cables are longer than necessary or are disconnected from equipment, they can be awkward and untidy. 
     Prior art cable retractors exist that allow the extension and retraction of cables. Kim et al., U.S. Patent Publication No. 2008/0055237, discloses a cable retractor having multiple spring biased pulleys that move towards each other during cable extension and away from each other under spring tension during retraction. Rabinowitz, U.S. Patent Publication No. 2008/0156922 and Feinstein et al., U.S. Pat. No. 8,469,305 each disclose a cable retractor that includes a stationary and a movable set of pulleys around which the cable is wound. A spring biases the movable pulleys away from the stationary pulleys. Extension of the cable pulls the movable pulleys closer to the stationary pulleys against the spring&#39;s tension. When the extended cable is released, the spring tension moves the movable pulleys away from the stationary pulleys, retracting the cable. Feinstein et al. discloses a speed control mechanism that includes a gear attached to one of the stationary pulleys and a rotary damper attached to the gear that attempts to control retraction speed by controlling the rotation speed of the pulley. 
     Existing cable retractors provide at most limited control over the speed at which the cable is retracted. What is needed is an effective adjustable speed control for a cable retractor that is easily adjustable to be usable with a variety of cable types. 
     SUMMARY OF THE INVENTION 
     The present invention is a speed control for a cable retractor. In one or more embodiments the cable retractor with which the speed control is used comprises a pulley that engages a cable that may be extended and retracted. A friction element configured to adjustably contact the cable adjacent to the pulley is attached to a movable linkage. In one or more embodiments, the movement of the linkage is constrained to move along a predetermined path such that movement of the linkage along the path alters the distance between the friction element and the pulley. In one or more embodiments a cantilevered spring is attached to the linkage. An adjustable control, for example a thumbscrew, is configured to move the spring in relation to the linkage in a manner that alters the position of the friction element with respect to the cable and/or the pressure exerted by the friction element on the cable. In one or more embodiments, the friction element comprises a one-way bearing that exerts a greater amount of friction on the cable when the cable retracts than when it is extended. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may be better understood, and its features made apparent to those skilled in the art by referencing the accompanying drawings. 
         FIG. 1 . is a cross sectional drawing illustrating a cable retractor with which the present invention may be used. 
         FIG. 2  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with a cable installed. 
         FIG. 3  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with its spring extended. 
         FIG. 4  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with its spring extended and with a cable installed. 
         FIG. 5  is a cross sectional drawing illustrating the cable retractor of  FIG. 1 . 
         FIG. 6  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with a cable installed. 
         FIG. 7  is a cross sectional drawing illustrating a cable stop assembly of the cable retractor of  FIG. 1 . 
         FIG. 8  is an exploded perspective drawing illustrating the cable stop assembly of  FIG. 7 . 
         FIGS. 9A-9D  are perspective views showing configurations of the cable retractor of  FIG. 1 . 
         FIG. 10  is a cross-sectional view of an embodiment of the speed control of the present invention. 
         FIG. 11  is an exploded view of an embodiment of the speed control of the present invention. 
         FIG. 12  is a detail view of an embodiment of the speed control of the present invention. 
         FIG. 13  is an exploded view of an embodiment of the speed control of the present invention. 
         FIG. 14  is a cross-sectional view of an embodiment of the speed control of the present invention. 
         FIG. 15  is a cross-sectional view of an embodiment of the speed control of the present invention. 
         FIG. 16  is a perspective view of components of an embodiment of the speed control of the present invention. 
         FIG. 17  is a detail view of an embodiment of the speed control of the present invention. 
         FIG. 18  is a detail view of an embodiment of the speed control of the present invention. 
         FIG. 19  is a perspective view of an embodiment of a thumb nut detent mechanism present invention. 
         FIG. 20  is a perspective view of an embodiment of a thumb nut detent mechanism present invention. 
         FIG. 21  is a perspective view of an embodiment of a thumb nut detent mechanism present invention. 
     
    
    
     The use of the same reference symbols in different drawings indicates similar or identical items. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a cross sectional drawing illustrating a cable retractor that can be used with one or more embodiments of the speed control of the invention. The cable retractor of  FIG. 1  comprises an articulate housing assembly comprising a cable stop housing  126  and a pulley housing  138 . Cable stop housing  126  is pivotably coupled to pulley housing  138  such that cable stop housing  126  and pulley housing  138  can be rotated with respect to each other about an axis, for example, the first pulley axle  104  of first pulley set  103 . Alternatively, a different axis than first pulley axle  104  of first pulley set  103  may be used to pivotably couple cable stop housing  126  to pulley housing  138 . 
     A cable stop assembly  129  comprising a cable stop mechanism is coupled to the cable stop housing  126 . Cable stop assembly  129  comprises a cable stop actuator button  132 , which may be used to release the cable stop assembly  129  from frictionally detaining a cable  133  routed through cable stop assembly  129 . When the cable stop assembly is released, the cable retractor exerts a motive force on cable  133  to retract cable  133  into the articulate housing. A cable stop collar  134  may be attached to cable  133  to prevent cable connector  135  from being pulled into contact with cable stop assembly  129 . 
     A first pulley assembly comprising first pulley set  103  and first pulley axle  104  are disposed within pulley housing  138 . First pulley set  103  includes one or more pulleys that rotate independently of each other mounted to a common axle, such as, for example, first pulley axle  104 . In one or more embodiments, first pulley set  103  includes a pair of pulleys  103   a  and  103   b , as shown in  FIG. 5 . A second pulley assembly  105  comprising second pulley set  101 , second pulley axle  102 , spring  108 , spring axle  107 , and spring hub  106  is also disposed within pulley housing  138 . Second pulley set  101  includes one or more pulleys that rotate independently of each other mounted to a common axle, such as, for example, second pulley axle  102 . In one or more embodiments, second pulley set  101  includes a pair of pulleys  101   a  and  101   b , as shown in  FIG. 5 . 
     Spring  108  is a constant force spring which exerts an approximately constant amount of force regardless of how far spring  108  has been extended or retracted within its working range of motion. Spring  108  may be a coiled flat spring which is coiled around spring axle  107 , allowing spring  108  to unwind around spring hub  106  while spring  108  is being extended and to wind back around spring axle  107  as spring  108  is being retracted. 
     Spring  108  is connected to end cap  115  by spring mounting screw  109 . Thus, second pulley assembly  105  is drawn closer to end cap  115  when spring  108  is relaxed and wound around spring axle  107  and is farther from end cap  115  when spring  108  is extended and unwound from spring axle  107 . Spring  108  urges second pulley assembly  105  away from the first pulley assembly comprising first pulley set  103 . 
     End cap  115  comprises first end cap lug  113 , second end cap lug  116 , and mounting lug  111 . A first end cap lug aperture  114  is defined in first end cap lug  113 . As second end cap lug aperture  117  is defined in second end cap lug  116 . A screw is inserted through pulley housing  138  and first end cap lug aperture  114  to secure the end cap  115  to the pulley housing  138 . Another screw is inserted through pulley housing  138  and second end cap lug aperture  117  to secure the end cap  115  to the pulley housing  138 . Mounting lug  111  defines mounting lug aperture  112 . A rod or fastener may be inserted through mounting lug aperture  112  to secure the cable retractor to a cable access enclosure. 
     The cable retractor may further comprise a cable clamp assembly  118 . Cable clamp assembly  118  is attached, for example, to pulley housing  138  using cable clamp mounting screw  124 . Cable clamp assembly  118  comprises cable clamp flexure  119 , cable clamp movable engagement portion  120 , and cable clamp fixed engagement portion  121 , where cable clamp flexure  119  allows cable clamp movable engagement portion  120  to be moved relative to cable clamp fixed engagement portion  121  to allow cable  133  to be installed in or removed from cable clamp aperture  125  defined between cable clamp movable engagement portion  120  and cable clamp fixed engagement portion  121 . A cable clamp threaded stud  122  engages cable clamp fixed engagement portion  121 . For example, cable clamp threaded stud  122  may be screwed into or molded into cable clamp fixed engagement portion  121 . Cable clamp threaded stud  122  extends through an aperture defined in cable clamp movable engagement portion  120  beyond which cable clamp nut  123  engages cable clamp threaded stud  122 . Cable clamp nut  123  may be rotated to increase or decrease the spacing of cable clamp aperture  125 , thereby decreasing or increasing, respectively, the pressure applied by cable clamp fixed engagement portion  121  and cable clamp movable engagement portion  120  on the portion of cable  133  occupying cable clamp aperture  125 . By using cable clamp nut  123  to decrease the pressure on the portion of cable  133  occupying cable clamp aperture  125 , that portion of cable  133  may be removed from cable clamp aperture  125 , and another cable  133  may be inserted in place thereof. Cable clamp assembly  118  is separable from the pulley housing to facilitate installation of cable  133 . 
       FIG. 2  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with a cable installed. A cable stop collar  134  is attached near connector  135  at one end of cable  133 . Cable  133  is installed within cable stop assembly  129 . Cable stop assembly  129  operably frictionally engages a first portion of cable  133 . Cable  133  extends toward first pulley set  103 , where a first pulley  103   a  of first pulley set  103  operably engages a second portion of cable  133  around a first portion of a first circumferential surface of first pulley  103   a . Cable  133  extends toward second pulley set  101 , where second pulley  101   a  of second pulley set  101  operably engages a third portion of cable  133  around a first portion of a second circumferential surface of second pulley  101   a . From second pulley  101   a , cable  133  extends toward third pulley  103   b  of first pulley set  103 , where third pulley  103   b  operably engages a fourth portion of cable  133  around a circumferential surface of third pulley  103   b . From third pulley  103   b , cable  133  extends toward fourth pulley  101   b  of second pulley set  101 , where fourth pulley  101   b  operably engages a fifth portion of the cable around a circumferential surface of fourth pulley  101   b . From fourth pulley  101   b , cable  133  extends to cable clamp assembly  118 , where cable clamp assembly  118  operably frictionally engages a sixth portion of cable  133 . From cable clamp assembly  118 , cable  133  extends to cable connector  201  at a second end of cable  133  opposite the end of cable  133  where cable connector  135  is attached. 
     The second portion of cable  133  lies between the first portion of cable  133  and the third portion of cable  133  along the length of cable  133 . The third portion of cable  133  lies between the second portion of cable  133  and the fourth portion of cable  133  along the length of cable  133 . The fourth portion of cable  133  lies between the third portion of cable  133  and the fifth portion of cable  133  along the length of cable  133 . The fifth portion of cable  133  lies between the fourth portion of cable  133  and the sixth portion of cable  133  along the length of cable  133 . 
       FIG. 3  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with its spring extended. With spring  108  extended, second pulley assembly  105  is translated linearly and radially with respect to first pulley set  103 , such that second pulley set  101  is closer to first pulley set  103  than when spring  108  is retracted. As spring  108  is extended, a straightened portion of spring  108  extends between second pulley assembly  105  and spring mounting block  110  of end cap  115 . As spring  108  is retracted, that straightened portion of spring  108  is wound around spring axle  107 , with the remainder of spring  108  around spring axle  107  rotating about spring axle  107  to accommodate the winding of the straightened portion of spring  108 . 
       FIG. 4  is a cross sectional drawing illustrating the cable retractor of  FIG. 1  with its spring extended and with a cable installed.  FIG. 4  illustrates the elements shown in  FIG. 2 , with cable  133  installed, but with spring  108  extended. Cable  133  has been rotated about first pulley set  103  and second pulley set  101  to bring second pulley set  101  closer to first pulley set  103 , reducing the lengths of cable  133  between first pulley  103  set and second pulley  101  set. The motive force for such reconfiguration of the cable retractor is provided by pulling on cable stop collar  134  so as to draw a portion of cable  133  extending from cable stop collar  134  out of the cable retractor. After that portion of cable  133  is withdrawn from the cable retractor, cable stop assembly  129  operates to frictionally retain cable  133  until cable stop actuator button  132  is depressed. 
     When cable stop actuator button  132  is depressed, cable stop assembly  129  allows the extended portion of cable  133  to be retracted into the cable retractor. The motive force for the retraction is provided by spring  108  acting on second pulley assembly  105  to draw second pulley set  101  farther from first pulley set  103 , thereby increasing the lengths of cable  133  between first pulley set  103  and second pulley set  101 . 
       FIG. 5  illustrates the cable retractor of  FIG. 1  as viewed from an angle ninety degrees from the angle of view of  FIG. 1 . 
       FIG. 6  illustrates the cable retractor of  FIG. 2 , with cable  133  installed, as viewed from an angle ninety degrees from the angle of view of  FIG. 2 . 
       FIG. 7  is a cross sectional drawing illustrating cable stop assembly  129  of the cable retractor of  FIG. 1 . Cable stop assembly  129  comprises cable stop assembly housing  701 , cable stop actuator  702 , cable stop actuator button  132 , upper cable stop assembly screw boss  703 , cable stop actuator guide  704 , cable stop actuator rack gear teeth  705 , cable stop cam  706 , cable stop cam pinion gear teeth  707 , cable stop axle  708 , cable stop cam engagement surface  709 , cable stop spring  712 , lower cable stop assembly screw boss  718 . Cable stop spring  712  is coiled around cable stop axle  708 . Cable stop assembly housing  701  comprises cable stop cam base  710 , which defines cable stop cam base engagement surface slot  711 . A tab defined in cable stop housing  126  projects into cable stop cam base engagement surface slot  711  to provide a cable stop cam base engagement surface so that a cable  133  can be positioned between the tab and cable stop cam engagement portion  709  of cable stop cam  706 . When cable stop assembly housing  701  is disassembled from cable stop housing  126 , cable stop cam base engagement surface slot  711  provides space for a cable  133  to be removed from and/or installed into cable stop assembly housing  701 . Cable stop assembly housing  701  defines upper cable aperture  713  and lower cable aperture  714  to allow cable  133  to be inserted through cable stop cam base engagement surface slot  711  adjacent to cable stop cam engagement surface  709 . Cable stop actuator  702  transfers the force via cable stop actuator rack gear teeth  705  and cable stop cam pinion gear teeth  707  to cable stop cam  706 . Cable stop cam engagement surface  709  of cable stop cam  706  exerts force against the portion of cable  133  located between cable stop cam engagement surface  709  and the tab of cable stop  126  that fills cable stop cam base engagement portion surface slot  711 , which frictionally detains cable  133 , preventing cable  133  from being retracted into the cable retractor. When cable stop actuator button  132  is depressed, cable stop actuator rack gear teeth  705  operate on cable stop cam pinion gear teeth to move cable stop cam  706  so that cable stop cam engagement surface  709  moves away from the portion of cable  133  detained in cable stop assembly  129 , reducing the friction with which that portion of cable  133  is detained, thereby allowing cable  133  to be retracted into the cable retractor. Such retraction can continue until cable stop collar  134  contacts cable stop assembly housing  701  or until cable stop actuator button  132  is released. As cable stop actuator button  132  is depressed, cable stop spring  712  is wound around cable stop axle  708 . Cable stop spring  712  exerts force through cable stop cam pinion gear teeth  707  and cable stop actuator rack gear teeth  705  to bias cable stop actuator  702  and cable stop actuator button  132  upward (i.e., toward a released position). As cable stop actuator button  132  is released, cable stop spring  712  is unwound somewhat, relaxing somewhat the force it had applied to cable stop actuator button  132 . Cable stop collar  134  is configurable to abut a portion of cable stop assembly housing  701  to limit cable retraction. Alternatively, cable stop actuator spring  712  may be implemented as, for example, a spring between cable stop actuator button  132  and a portion of cable stop assembly housing  701 , such as cable stop assembly screw base  703 , as a spring between cable stop actuator  702  and cable stop assembly housing  701 , as a spring between cable stop cam  706  and cable stop assembly housing  701 , or in other similar configurations. 
     Cable stop assembly housing  701  further comprises cable stop assembly boss  715 , which defines upper cable stop assembly screw collar  716  and lower cable stop assembly screw collar  717 , which define holes for cable stop assembly screws  139  and  131 , respectively. As noted, cable stop assembly housing  701  comprises upper cable stop assembly screw boss  703  and lower cable stop assembly screw boss  718 . Screws engaging upper cable stop assembly screw boss  703  and lower cable stop assembly screw boss  718  can be used to hold cable stop assembly housing  701  together. 
       FIG. 8  is an exploded perspective drawing illustrating cable stop assembly  129 . Cable stop assembly  129  comprises cable stop assembly housing  701 , which comprises portions  801  and  802 . Portions  801  and  802  can receive components of cable stop assembly and be assembled to form cable stop assembly  129 . Cable stop cam  706  comprises cable stop cam sleeve  803 , which surrounds cable stop axle  708  and is surrounded by the coiled portion of cable stop spring  712 . Portion  801  of cable stop assembly  701  comprises cable stop axle boss  807 , which coaxially retains cable stop axle  708  in position within cable stop assembly housing  701 . Portion  801  of cable stop assembly housing  701  comprises upper cable stop assembly screw boss  703  and lower cable stop assembly screw boss  718 . Portion  802  of cable stop assembly housing  701  defines upper hole  805  and lower hole  806 . With the components enclosed within cable stop assembly housing  701  installed therein, portions  801  and  802  can be assembled together. When so assembled, upper hole  805  of portion  802  aligns with upper cable stop assembly screw boss  703  and lower hole  806  aligns with lower cable stop assembly screw boss  718 . Upper screw  804  can be installed through upper hole  805  to engage upper cable stop assembly screw boss  703  and lower screw  808  can be installed through lower hole  806  to engage lower cable stop assembly screw boss  718 , thereby fastening together portions  801  and  802  of cable stop assembly housing  701 . 
       FIGS. 9A to 9D  are perspective views showing configurations of the cable retractor of  FIG. 1 .  FIG. 9A  shows the cable retractor configured such that cable stop housing  126  is pivoted with respect to pulley housing  138 .  FIG. 9B  shows the cable retractor configured such that cable stop housing  126  is pivoted to be inline with pulley housing  138 .  FIG. 9C  shows the cable retractor configured as in  FIG. 9A  mounted to a cable access enclosure  910 , which may, for example, be a “Cable Cubby” manufactured by RGB Systems, Inc.  FIG. 9D  shows the cable retractor configured as in  FIG. 9B  mounted to cable access enclosure  910 . 
       FIGS. 10 and 11  show an embodiment of the speed control of the present invention.  FIG. 10  is a cutaway view showing an embodiment of the speed control of the present invention.  FIG. 11  is an exploded view of the speed control embodiment of  FIG. 10 . Some of the components shown in  FIG. 11  are not visible in  FIG. 10 . 
       FIGS. 10 and 11  show the speed control of the present invention installed in a cable retractor  1000 . Cable retractor  1000  includes pulley housing  1010  and cable stop housing  1020 . The side of pulley housing  1010  has been rendered transparent in  FIG. 10  such that certain internal components are visible. Only some of the internal components of cable retractor  1000  are shown so as to not obscure the speed control of the present invention. For example, the spring biased pulley assembly that provides for retraction and extension of cable  1035  (such as, for example, pulley assembly  105  of the embodiment of  FIG. 1 ) is not shown in  FIG. 10 . 
     In the embodiment of  FIGS. 10 and 11 , components of the speed control include a bracket  1050 , a drag assembly  1005 , and a spring  1055 . 
     Bracket  1050 , which may be formed from a plastic, metal, or any other suitable material, is configured to be mountable to pulley housing  1010 , for example via screws attaching bracket  1050  to mounting bosses  1135  (shown in  FIG. 11 ). 
     Drag assembly  1005  is configured to exert an adjustable amount of friction on cable  1035  as cable  1035  is retracted into pulley housing  1010  so as to control the retraction speed. In one or more embodiments, drag assembly  1005  is configured to be mountable adjacent to a pulley set of cable retractor  1000 , such as, for example, pulley set  103  of the embodiment of  FIG. 1 . In the embodiment of  FIGS. 10 and 11 , drag assembly  1005  comprises two end plates  1070  and  1180  that are kept spaced apart by posts  1145  and  1155 . Posts  1145  and  1155  are fastened to endplates  1070  and  1180  by fasteners  1065 ,  1085 ,  1190 , and  1195 , which may, for example, comprise screws or other threaded fasteners that engage mating threaded holes in posts  1145  and  1155 . Endplates  1070  and  1180  can be made of metal, plastic, composite, or any other suitable material. In the embodiment of  FIGS. 10 and 11 , endplates  1070  and  1180  include elongated oval slots  1075  and  1115 , respectively, that are configured to accept pulley axle  1185 . Posts  1145  and  1155  are dimensioned so as to allow at least one pulley  1165  of a pulley set of cable retractor  1000  to be sandwiched between endplates  1070  and  1180  when pulley  1165  is mounted to pulley axle  1185  via pulley bearing  1175  and drag assembly  1005  is mounted to pulley axle  1185  via slots  1075  and  1115 . In the embodiment of  FIGS. 10 and 11 , a one-way bearing  1140  is mounted to post  1145  between endplates  1070  and  1180 . 
     In the embodiment of  FIGS. 10 and 11 , drag assembly  1005 , pulley axle  1185 , and pulleys  1165  and  1170  are configured to fit between the sidewalls of pulley housing  1010 . In one or more embodiments, drag assembly  1005  and pulleys  1165  and  1170  are mounted to pulley axle  1185 , and the resulting assembly is fastened to pulley housing  1010  and cable stop housing  1020  via a fastener  1080  (which may be a screw) inserted through hole  1150  of cable stop housing  1020  and hole  1160  of pulley housing  1010  such that it engages a mating threaded hole in pulley axle  1185 . In one or more embodiments, a second fastener is inserted through holes in opposite sides of cable stop housing  1020  and pulley housing  1010  to engage a second threaded hole in the opposite side of pulley axle  1185 . In the resulting assembly, cable stop housing  1020  and pulleys  1165  and  1170  are all pivotably attached to pulley housing  1010  via pulley axle  1185 . In alternate embodiments, cable stop housing  1020  and pulleys  1165  and  1170  may be configured to rotate about different axes. 
     In one or more embodiments, cantilever spring  1055  is formed from a length of spring wire or flat spring ribbon. In the embodiment shown in  FIG. 11 , cantilever spring  1055  is formed from a length of spring wire, and includes a loop  1130  formed at one end, a bent portion  1102  adjacent to loop  1130 , and a straight portion  1104 . Straight portion  1104  of cantilever spring  1055  is attached to bracket  1050  by pivot pin  1045  that engages hole  1110  in bracket  1050 . In one or more embodiments, pivot pin  1045  has a hole through which the end of cantilever spring  1055  may be inserted, and a set screw  1100  that is configured to lock cantilever spring  1055  in position in pivot pin  1045 . Loop  1130  of cantilever spring  1055  is attached to drag assembly  1005  via post  1155 . In one or more embodiments, a threaded post  1060  with a hole at a bottom end is mounted to straight portion  1104  of cantilever spring  1055 . Threaded post  1060  is configured to engage a mating opening  1105  in bracket  1050  when cantilever spring  1055  is attached to bracket  1050 . A thumb nut  1090  is disposed on threaded post  1060 . Thumb nut  1090  may be threaded onto threaded post  1060  until its underside engages bracket  1050  adjacent to opening  1105 . Further tightening of thumb nut  1090  on threaded post  1060  causes straight portion  1104  of cantilever spring  1055  to be pulled upwards in a vertical direction. Subsequent loosing of thumb nut  1090  allows straight portion  1104  of cantilever spring  1055  to be released in a downward position. Adjustment of the position of thumb nut  1090  on post  1060  adjusts the spring force exerted by loop  1130  of cantilever spring  1055  on drag assembly  1005 . 
     In one or more embodiments, thumb nut  1090  is provided with a detent mechanism to prevent thumb nut  1090  from rotating after the desired spring force setting has been achieved. One embodiment of such a detent mechanism is shown in  FIGS. 19-21 . In the embodiment of  FIGS. 19-20 , thumbnut  1910  is provided with a series of radial ridges  2110  on its bottom face that are configured to mate with a matching set of radial ridges  2020  formed on bracket  1050  when thumbnut  1910  is mounted to threaded post  1060 . In the embodiment of  FIGS. 19-21 , the sidewalls  1920  of bracket  1050  adjacent to opening  1105  are curved to accommodate post  1060 , and radial ridges  2020  are formed on the faces of the curved portions so as to mate with radial ridges  2110  of thumb nut  1910 . The embodiment of  FIGS. 19-21  also includes projections  2010  formed in bracket  1050  adjacent to radial ridges  2020  to help maintain thumb nut  1910  in place during adjustment. When thumb nut  1910  has been adjusted such that loop  1130  of cantilever spring  1055  exerts a generally upward force on drag assembly  1005 , cantilever spring  1055  exerts a generally downward force on post  1060  and thumb nut  1910 , pressing raised ridges  2110  of thumb nut  1910  against mating raised ridges  2020  of bracket  1050 , holding thumb nut  1910  in place. 
     In the embodiment of  FIGS. 10 and 11 , adjustment of thumb nut  1090  up and down (arrow A in  FIG. 10 ) translates into an adjustable amount of spring force being exerted by loop  1130  on drag assembly post  1155  of drag assembly  1005  (arrow B). As shown in  FIG. 12 , slots  1075  and  1115  of drag assembly  1005  restrain movement of drag assembly  1005  generally in the direction of arrow C. Drag assembly  1005  translates the spring force exerted on post  1155  by loop  1130  of cantilever spring  1055  into a force exerted by one-way bearing  1040  on cable  1035 , pushing cable  1035  against pulley  1165  generally in the direction of arrow D. The cantilever configuration of cantilever spring  1055  allows one way bearing  1040  to “float” up and down in the direction of arrow D with variations in the thickness or other imperfections of cable  1035  without a great change in the amount of force exerted by one-way bearing  1140  on cable  1035  as cable  1035  is extended or retracted. The force exerted by one-way bearing  1140  on cable  1035  can be viewed as in some ways mimicking the force that would be exerted on cable  1035  by a person&#39;s finger if the finger were placed on cable  1035  during retraction or extension. 
     The configuration of cantilever spring  1055  and drag assembly  1005  of the embodiment of  FIGS. 10-12  transforms the adjustable force that cantilever spring  1055  exerts on drag assembly  1005  into an adjustable and variable amount of friction exerted by one-way bearing  1140  on cable  1035 . In the embodiment of  FIG. 12 , one-way bearing  1140  freely rotates in the direction of arrow E, which corresponds to extension of cable  1035  in the direction of arrow F. Because of that free rotation, little friction is exerted on cable  1035  by one-way bearing  1140  during extension of cable  1035 . One-way bearing  1140  does not rotate in the opposite direction, which corresponds to retraction of cable  1035 . Accordingly, the force of one-way bearing  1140  on cable  1035  creates friction that controls the retraction speed during retraction. The amount of such friction, and hence the retraction speed, can be adjusted by thumb nut  1090 . 
       FIG. 13  shows an alternate embodiment of drag assembly  1005  that does not use a one-way bearing. In the embodiment of  FIG. 13 , instead of the one-way bearing  1140  of the embodiment of  FIGS. 10-12 , a sleeve  1305  is placed over post  1145  between end plates  1070  and  1180 , such that the surface of sleeve  1305  contacts the surface of cable  1035  and exerts force on cable  1035  in the same manner as the surface of one-way bearing  1140  of the embodiment of  FIGS. 10-12 . Sleeve  1305  may be rotatably mounted to post  1145  or may be irrotatably fixed in position. Sleeve  1305  may be made of a metal (e.g. brass, copper, aluminum, steel, etc.), a plastic (e.g. PVC, ABS, nylon, Teflon, etc.), a composite, or any other suitable material. Sleeve  1305  may be smooth or have a regular or irregular surface texture, and may, for example have a surface that produces a greater amount of contact friction in one direction than the other, or may be configured to produce approximately the same amount of contact friction in both directions. In one or more alternative embodiments, sleeve  1305  may be omitted, such that the surface of post  1145  contacts the surface of cable  1035  directly. In such embodiments, post  1145  may be made of any of the same materials described above for sleeve  1305 , and may have any of the same surface features or characteristics. 
       FIGS. 14 and 15  show embodiments of the cable speed control of the invention that use a rigid or semi-rigid lever and spring in place of the cantilever spring of the embodiment of  FIGS. 10-12 . In the embodiment of  FIG. 14 , a lever  1405  is pivotably mounted via axle  1410  to bracket  1450 , which is mounted to pulley housing  1010 . Lever  1405  may be made of a metal, plastic, wood, a composite, or any other suitable material. A compression spring  1415  is positioned to exert a downwards spring force on an end  1445  of lever  1405  generally in the direction of arrow K. The amount of force exerted by compression spring  1415  on end  1445  of lever  1405  is adjustable, for example by an adjustment screw  1420  that is threaded into a mating hole in bracket  1450 . The downward force exerted by compression spring  1415  on end  1445  of lever  1405  is converted by lever  1405  into a generally upward force exerted by lever  1405  on post  1155  of drag assembly  1005  generally in the direction of arrow M. The ratio of the magnitude of the force exerted by compression spring  1415  on end  1445  of lever  1405  to the magnitude of the force exerted by lever  1405  on drag assembly  1005  depends of the position of pivot axle  1410 . In the embodiment of  FIG. 14 , the length of the portion  1425  of lever  1405  between pivot axle  1410  and compression spring  1415  is smaller than the length of the portion  1430  of lever  1405  between pivot axle  1410  and post  1155  of drag assembly  1005 . In one or more embodiments, the length of portion  1425  is approximately between one fifth and one third of the length of portion  1430 , such that the force exerted by lever  1405  on drag assembly  1005  is approximately between one fifth and one third of the force exerted by compression spring  1415  on end  1445  of lever  1405 . 
     Drag assembly  1005  translates the force exerted by lever  1405  on drag assembly  1005  into an generally upward force exerted by post  1145  (which may include a one-way bearing as in the embodiment of  FIGS. 10-12  or a sleeve as in the embodiment of  FIG. 13 ) on cable  1035  (not visible in  FIG. 14 ) generally in the direction of arrow N. The longer length of portion  1430  of lever  1405  compared to the length of portion  1425  of lever  1405  has the effect that displacements of post  1145  caused by variations in the thickness of cable  1035  are translated into smaller displacements of end  1445  of lever  1405  and of compression spring  1415 . Post  1145  may thus “float” with imperfections in the thickness of cable  1035  in a similar manner as in the embodiment of  FIGS. 10-12  without great variation on the force exerted by post  1145  on cable  1035 . 
       FIG. 15  shows an embodiment of the speed control of the invention that utilizes an extension spring  1520  instead of the compression spring  1415  of the embodiment of  FIG. 14 . In the embodiment of  FIG. 15 , lever  1515  comprising a dogleg  1525  and an arm  1530  is pivotably attached to bracket  1550  via pivot axle  1535 . Extension spring  1520  extends between a hole  1510  in the end of dogleg  1525  and a pivot pin  1530  mounted to a projection  1555  of bracket  1550 . Thumb nut  1505  adjusts the tension that extension spring  1520  exerts on dogleg  1525  of lever  1515  generally in the direction of arrow P. Lever  1515  transforms the tension exerted by spring  1520  on dogleg  1525  into a generally upward force exerted by arm  1530  of lever  1515  on post  1155  of drag assembly  1005  generally in the direction of arrow R. Drag assembly translates the generally upward force exerted by lever  1515  on post  1155  into a generally upward force exerted by post  1145  (which may include a one-way bearing or sleeve) on cable  1035  (not shown in  FIG. 15 ) generally in the direction of arrow S. The ratio of the force exerted by post  1145  on cable  1035  depends on the ratio of the length of dogleg  1525  of lever  1515  to the length of arm  1530  of lever  1515 . In one or more embodiments, the length of dogleg  1525  is approximately between one fifth and one third of the length of arm  1530 , and the ratio of the force exerted by post  1145  on cable  1035  is approximately between one fifth and one third of the tension exerted by spring  1520  on dogleg  1525 . As in the embodiment of  FIG. 14 , the length of arm  1530  compared to dogleg  1525  allows post  1145  to “float” with imperfections in the thickness of cable  1035  in the same manner as in the embodiment of  FIGS. 10-12 . 
       FIGS. 16-18  show an alternative embodiment of a speed control for a cable retractor of the invention. Three components of this embodiment are shown in  FIG. 16 . These components include a flange plate  1610 , a pulley  1620 , and a rotary damper assembly  1630 . Rotary damper assembly  1630  includes a gear  1670  mounted to a rotary damper as are known to those of ordinary skill in the art. Flange plate  1610  includes a central opening configured to allow flange plate  1610  to be mounted to, for example, pulley axle  1185  of cable retractor  1000  of the embodiment of  FIG. 11  in place of end plate  1070 . Flange plate  1610  also includes a second opening  1650  sized to accept gear  1670  of rotary damper assembly  1630 , projections  1640  and  1645 , and mounting bosses  1615 ,  1625  and  1655 . Mounting bosses  1625  and  1655  are configured to align with mounting holes  1675  and  1680  of rotary damper assembly  1630  and to accept fasteners (e.g. screws) for mounting damper assembly  1630  such that gear  1670  faces and projects through opening  1650  into the plane of  FIG. 16 . 
     Pulley  1620  includes a central bore  1665  configured to accept a bearing, such as, for example, pulley bearing  1175  of the embodiment of  FIG. 11 . Pulley  1620  also includes gear teeth  1660  configured to mesh with gear  1670  of rotary damper assembly  1630  when rotary damper assembly  1630  is mounted to flange plate  1610  and flange plate  1610  and pulley  1620  are mounted to the same axle, for example pulley axle  1185  of the embodiment of  FIG. 11 . 
       FIG. 17  is a front partially transparent view showing the components of  FIG. 16  as well as additional components as mounted to, for example, pulley housing  1010  of the embodiment of  FIG. 11 . In  FIG. 17 , rotary damper assembly  1630  is shown mounted to flange plate  1610 , and both flange plate  1610  and pulley  1620  are shown mounted to pulley axle  1185 . Also included in the embodiment of  FIG. 17  are a stop block  1710  mounted to pulley housing  1010  that includes a fixed stop  1720  and an adjustable stop  1715 . Fixed stop  1720  may, for example, comprise a fixed projection of stop block  1710 . Adjustable stop  1715  may, for example, comprise a threaded screw that threads into a mating threaded hole in stop block  1710 . Adjustable stop  1715  is configured to prevent rotation of flange plate  1610  and end plate  1705  in the clockwise direction beyond the (adjustable) point at which projection  1640  of flange plate  1610  contacts adjustable stop  1715 . Fixed stop  1720  is configured to prevent rotation of flange plate  1610  in the counterclockwise direction beyond the point at which projection  1645  contacts fixed stop  1720 . 
     The operation of the speed control of  FIG. 17  is as follows. When cable  1035  retracts in the direction of arrow U (for example after cable stop actuator button  132  of the embodiment of  FIG. 1  is activated), friction between cable  1035  and pulley  1620  causes pulley  1620  to rotate clockwise in the direction of arrow W. The clockwise rotation of pulley  1620  causes gear  1670  of rotary damper assembly  1630  to spin in a counterclockwise direction, which causes rotary damper assembly  1630  to exert a force on flange plate  1610  to which it is mounted in the general direction of arrow Y. The magnitude of the force depends on the rotation speed of pulley  1620  and the damping characteristics of the rotary damper assembly  1630 . 
     The force exerted by rotary damper assembly  1630  on flange plate  1610  in the direction of arrow Y causes flange plate  1610  and end plate  1705  to rotate about pulley axle  1175  generally in the direction of arrow Z. Such rotation causes post  1145  or any sleeve or bearing mounted on post  1145  first to contact cable  1035 , as shown in  FIG. 18 . If the force exerted by damper assembly  1630  on flange plate  1610  is great enough, and adjustable stop  1715  is adjusted such that projection  1640  has not yet contacted adjustable stop  1715 , rotation of flange plate  1610  continues, causing a bend in cable  1035  at the point of contact between post  1145  or any sleeve or bearing mounted on post  1145  and cable  1035 . The contact between post  1145  or any sleeve or bearing mounted on post  1145  and cable  1035  plus any bend induced in cable  1035  creates friction on cable  1035 , slowing its retraction speed. As the retraction speed of cable  1035  slows, the rotation speed of pulley slows and the force exerted by rotary damper assembly on flange plate  1610  is reduced. Flange plate  1610  start rotating counterclockwise back towards their rest position, reducing the friction exerted by post  1145  or any sleeve or bearing mounted on post  1145  on cable  1035 , thereby allowing the retraction speed of cable  1035  to once again increase. This feedback characteristic causes an average retraction speed that is regulated by the damping characteristics of rotary damper assembly  1630  and the position of adjustable stop  1715 . 
     When cable  1035  is extended, the force exerted by rotary damper assembly  1630  on flange plate  1610  acts to urge flange plate  1610  to rotate counterclockwise until projection  1645  contacts fixed stop  1720 , moving post  1145  away from cable  1035  and reducing the friction exerted on cable  1035  during extension. 
     Thus, a speed control for a cable retractor has been described. Although the present invention has been described with respect to certain specific embodiments, it will be clear to those skilled in the art that the inventive features of the present invention are applicable to other embodiments as well, all of which are intended to fall within the scope of the present invention. For example, an embodiment similar to the embodiment of  FIGS. 16-18  could use a spring-loaded post instead of a rotary damper for applying variable resistance to a cable to control retraction speed. The post may, for example, be mounted in a slot in a link that pivots about the same axis as the pulley. The post would be spring loaded to move in the slot to compensate for various cable diameters. The link would pivot to a fixed stop at which the post does not contact the cable when the cable is extended and to an adjustable stop at which the post contacts and puts a bend in the cable when retracted. The amount of pivot would vary the amount of bend the cable is put through changing the retraction speed of the cable. In other embodiments, a mechanism similar to disk brakes on an automobile, motorcycle, bicycle etc. can be used that could be adjusted to vary the resistance to any or all pulleys in the system to regulate the retraction speed. Similarly, a drum brake type system could be used place adjustable resistance on any or all pulleys in the system to regulate the retraction speed. In other embodiments, an adjustable spring member could be used to directly contact the cable similar to a leaf spring. This spring member would be cantilevered so that one end presses the cable against a pulley and the other end is fixed to the cable retractor housing. An adjustment member such as a screw would deflect the spring adjusting the force and thus the retraction speed. In other embodiments, two opposing spring members could be used with the cable running in between. This friction exerted by the spring members on the cable would be adjustable to regulate the retraction speed of the cable. Alternatively, one of the spring members could be replaced with a fixed member. In yet other embodiments, the cable can be configured to run through a device similar to a belay device used in climbing. The belay device could be configured such that as cable speed increases, the device causes the cable to bend and contact a larger surface area of the device, increasing friction and thus regulating and reducing the cable retraction speed. In yet other embodiments, the post that provides friction on the cable could itself be a rotary damper, or be made of an assembly that includes a rotary damper, that would resist turning at a high rate of speed and thus reduce and regulate the retraction speed of the cable. Other embodiments of the present invention will be apparent to those of skill in the art.