Abstract:
A cable reel comprises a casing defining a cable exit opening and an access opening; a static electrical connection located externally of the casing; a spool rotatably received within the casing and having a circumferentially extending recess opening radially outwardly of the spool, the spool further having an inner axially extending recess and an axially open notch communicating between the circumferentially extending recess and the inner axially extending recess; a handset cable having a first end and a second end, the handset cable first end being attachable to a handset in use, at least a portion of the handset cable being windable into or out of the spool circumferentially extending recess upon rotation of the spool so as to extend from or retract into the cable exit opening; a ribbon cable having a first end and a second end, the ribbon cable first end being attached to the handset cable second end and the ribbon cable second end being attached to the static electrical connector whereby the ribbon cable is electrically connected between the static electrical connection and the handset cable; a cover, and releasable fastening means for removably and replaceably securing the cover over the access opening so that, with the cover removed, the spool is exposed in the access opening; whereby the handset cable with attached ribbon cable may be removed by unwinding from the spool and lifting from the notch for servicing or repair of the cable reel.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a cable reel which may be used in conjunction with a cradle and a handset, such as a telephone handset or remote control for electronic apparatus, such as is typically but not exclusively used in various modes of mass transport including aircraft, vessels, rail and road passenger vehicles. Such handsets and cradles may also be used to facilitate audience participation or interaction in theatres, arenas, lecture theatres, libraries and similar locations.  
           [0003]    2. Description of the Related Art  
           [0004]    It is known to provide a cradle in the armrest of a chair, such as a seat in an aircraft, for housing a handset comprising, for example, a telephone and/or a remote controller for in-flight entertainment apparatus. Such handsets can also include call functions for the in-flight staff. A typical example is the model RU-AA6501-01 of Matsushita Electrical Industrial Company Limited of Osaka, Japan. Similar handsets and cradles may also be mounted in other locations such as in or on aircraft bulkheads or seat backs: see for example U.S. Pat. Nos. 5,128,993, 5,410,597 and 5,155,766.  
           [0005]    Conventionally such cradles comprise a recess in which the handset is stowed and from which the handset can be removed for example by lifting. The handset is electrically powered and connected via a cable which is housed in and may be drawn from a cable reel as the handset is removed from the cradle. As the handset is stowed, the cable is rewound into the reel under spring action, so as to leave no potentially hazardous freely exposed cable loop. To simplify cradle installation as well as helping to ensure proper retraction of the cable, the reel may be housed in or mounted on the cradle, with the cable routed directly from the reel into the recess. Alternatively the cable reel may be mounted separately from the cradle with a cable run or guide extending therebetween (see for example U.S. Pat. No. 5,109,412 and International patent publication no. WO 95/29552).  
           [0006]    With repeated use of the handset, the cable is prone to wear. The cable or reel are often provided with a releasable locking mechanism to relieve the spring tension on the extended cable and prevent this tension from being experienced by the user. The locking mechanism is likewise prone to wear and damage in use. Prior art cable reels are not readily serviced or repaired “on site”, i.e. at the location (aircraft, vehicle, building etc) in which they are used. A particular difficulty arises because the handset cable is wound/unwound from a rotatable spool and connected to a ribbon cable coiled within the cable reel to provide an electrical connection between the moving handset cable and a stationary connector on the reel casing. The spool, handset cable and ribbon cable cannot be readily dismantled and reassembled without the use of specialist tools and off-site facilities.  
           [0007]    To simplify manufacture, a prior art cable reel developed by the present applicants has a spool comprising a pair of flanges defining between them a circumferential groove from which the handset cable is wound and unwound, a central, axially extending recess in which the ribbon cable is housed, and a notch in one of the flanges into which the handset cable and an attached ribbon cable can be simply laid so as to pass from the groove into the recess without the need to thread the cables through the spool in a direction along the cable axes, or the need to subsequently make up a connection between the ribbon cable and the handset cable. However these prior cable reels are manufactured as sealed units, either as a discrete unit for use with a separate handset cradle, or integrated with a handset cradle which forms a sealed housing for the reel. In either case, on site servicing of the cable reel is not practicable. Once the cable or other internal components of the reel become worn or damaged the entire reel or cradle assembly must be discarded.  
           [0008]    It is an object of the present invention to provide a cable reel which may be readily serviced on site without the need for special tools or equipment.  
           [0009]    It is a further object of the invention to provide a cable reel having cable components which may readily be replaced without the use of special tools or equipment.  
           [0010]    It is a further preferred object of the invention to provide a cable reel having a mechanism for locking the cable in an extended position against a retraction spring force, in which the mechanism is accessible for servicing or repair.  
         SUMMARY OF THE INVENTION  
         [0011]    The invention provides a cable reel comprising:  
           [0012]    a casing defining a cable exit opening and an access opening;  
           [0013]    a static electrical connection located externally of the casing;  
           [0014]    a spool rotatably received within the casing and having a circumferentially extending recess opening radially outwardly of the spool, the spool further having an inner axially extending recess and an axially open notch communicating between the circumferentially extending recess and the inner axially extending recess;  
           [0015]    a handset cable having a first end and a second end, the handset cable first end being attachable to a handset in use, at least a portion of the handset cable being windable into or out of the spool circumferentially extending recess upon rotation of the spool so as to extend from or retract into the cable exit opening;  
           [0016]    a ribbon cable having a first end and a second end, the ribbon cable first end being attached to the handset cable second end and the ribbon cable second end being attached to the static electrical connector whereby the ribbon cable is electrically connected between the static electrical connection and the handset cable;  
           [0017]    a cover, and  
           [0018]    releasable fastening means for removably and replaceably securing the cover over the access opening so that, with the cover removed, the spool is exposed in the access opening; whereby the handset cable with attached ribbon cable may be removed by unwinding from the spool and lifting from the notch for servicing or repair of the cable reel.  
           [0019]    The invention may also provide a cradle for a handset comprising:  
           [0020]    a casing defining an access opening and a cable exit opening, the cable exit opening communicating with a handset receiving recess formed in the casing;  
           [0021]    a static electrical connection located externally of the casing;  
           [0022]    a spool rotatably received within the casing;  
           [0023]    a handset cable having a first end and a second end, the handset cable first end being attachable to a handset in use, at least a portion of the handset cable being windable onto or off the spool upon rotation thereof so as to extend from or retract into the cable exit opening;  
           [0024]    a ribbon cable having a first end and a second end, the ribbon cable first end being attached to the handset cable second end and the ribbon cable second end being attached to the static electrical connector whereby the ribbon cable is electrically connected between the static electrical connection and the handset cable;  
           [0025]    a cover, and  
           [0026]    releasable fastening means for removably and replaceably securing the cover over the access opening so that, with the cover removed, the spool is exposed in the access opening for servicing or repair.  
           [0027]    The invention may further provide a repair kit for a cable reel, comprising:  
           [0028]    a static connector;  
           [0029]    a ribbon cable having first and second ends, the ribbon cable first end being preassembled to the static connector; and  
           [0030]    a handset cable having first and second ends, the handset cable first end being preassembled to the ribbon cable second end.  
           [0031]    The invention and various preferred objects, features and advantages thereof will be further understood from the following description of illustrative embodiments made with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]    [0032]FIG. 1 is a perspective view from above of a handset cradle embodying the present invention;  
         [0033]    [0033]FIG. 2 is a perspective view from below of the cradle of FIG. 1;  
         [0034]    [0034]FIG. 3 shows the cradle of FIG. 1 partly assembled;  
         [0035]    [0035]FIG. 4 is an exploded view of the spool shown in FIG. 3 with certain parts omitted for clarity;  
         [0036]    [0036]FIG. 5 is a view from above showing the spool of FIG. 4 with a return spring and spindle assembly installed;  
         [0037]    [0037]FIG. 6 shows a cable grip on an enlarged scale;  
         [0038]    [0038]FIG. 7 is a view similar to FIG. 5 showing the spindle, ribbon cable and handset cable installed, with the handset cable in the retracted position,  
         [0039]    FIGS.  8 - 10  show a push button operated cable reel brake which may be used in the handset cradle of FIG. 1;  
         [0040]    FIGS.  11 - 13  show an alternative cable reel brake and  
         [0041]    [0041]FIG. 14 is a perspective view of a discrete cable reel embodying the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0042]    Referring to FIG. 1, a cradle  10  for a telephone handset comprises a casing  12  having a collar  14  by which the cradle  10  may be located partially recessed within a chair arm (not shown). The casing  12  has a cable exit opening  16  from which a handset cable  18  extends into a handset stowage recess  20  (the handset not shown). The cradle  10  also has a spool brake release button  22  and, protruding into the stowage recess  20 , a spool brake reset trigger  24  whose operation will be explained later.  
         [0043]    As best shown in FIGS. 2 and 3, a cover  26  is removably and replaceably secured over an access opening  28  formed in the bottom of the casing  12 . Screws  30 ,  32  hold the cover  26  in place, with the screws  32  also securing a strain relieving outlet  34  for ribbon cable  36  second end  38 . A static electrical connector in the form of a multiplug  40  is fixed to the ribbon cable second end  38 . The cover  26  is further secured by a tongue  42  which engages beneath a lip  44  formed on the casing  12 . The opening  28  gives access to a spool chamber  46  in which is housed a spool  48  having a radially outwardly opening, peripherally extending recess  50  from which the handset cable  18  is wound and unwound.  
         [0044]    The spool  48  also has an inner, axially extending recess  52  which is closed by a snap fit lid  54  and houses a major portion of the ribbon cable  36  as further explained later. The spool  48  is rotatably carried on a hollow spindle  56  having a bifurcated end  58 , FIG. 4, which is non-rotatingly snap fitted into a pair of D slots  60  formed in the bottom of spool chamber  46 . As shown in FIG. 3, the cover  26  and lid  54  are threaded onto the ribbon cable second end  38  with a spacing washer  62  therebetween. When assembled, the free end of the spindle protrudes through lid  54 , washer  62  and cover  26  so that the hollow spindle interior provides an exit route for the ribbon cable  36  from the spool inner recess  52  to beneath the strain relieving outlet  34 .  
         [0045]    As shown in FIG. 4, the spool  48  has a spring accommodating recess  64  disposed opposite the axial recess  52 . A spiral spring  66  has a hooked end  68  engaged in an anchor slot  70  formed in the rim of recess  64 . The other end  72  of the spring  66  is curled to fit within a slot  74  in the bifurcated end  58  of the spindle  56 . As the spool  48  rotates relative to the spindle  56 , the spring  66  is tensioned to provide a return bias for retracting the handset cable  18 .  
         [0046]    Referring to FIGS. 4 and 5, the spool  48  has an axially open notch  76  extending through the wall separating the peripherally extending recess  50  from the inner axially extending recess  52 . A lower portion  78  of the notch  76  leads from the peripheral recess  50  to a depression  80  formed in the bottom of inner axially extending recess  52 . A rectangular through hole  82  communicates between the depression  80  and the spring recess  64 .  
         [0047]    A pair of wedge blocks  86  having toothed faces  90  are joined by an offset flexible strap  88  to form a cord grip  84 , FIG. 6. The strap  88  is passed through the hole  82  from the depression  80  to lie in a rebate  92  surrounding the end of the hole  82  where it enters the spring recess  64 . The wedge blocks  86  lie between convergent flanks  94  of the depression  80  on either side of the hole  82 .  
         [0048]    Prior to installation in the spool  48 , the handset cable second end  96  is electrically connected to the ribbon cable first end  98  by compact, high quality sheathed joints  100 , formed for example by laser welding. FIG. 7 shows this connection in position in the spool  48 . As may be seen from FIGS. 3 and 7, the static connection multiplug  40 , ribbon cable  36 , cover  26 , spacer washer  62 , lid  54 , sheathed joints  100 , handset cable  18 , a handset strain relief block  102  and a handset multiplug  104  together constitute a wiring harness assembly installable in the spool  48  as a preassembled unit, thereby facilitating refurbishment and repair, as well as initial installation. The wiring harness assembly may thus be supplied as a repair kit for worn or damaged handset cradles  10 .  
         [0049]    With the spool  48 , spring  66 , spindle  56  and cord grip  84  subassembly snapped into the D-slots in the base of the spool cavity  28 , the wiring harness assembly is installed by first dropping the handset cable second end  96  with attached ribbon cable  36  laterally into the notch  76  in the spool  48  and thence into the notch portion  78  so as to lead handset cable second end  96  out of the circumferential recess  50  and between the wedge blocks  86  of cord grip  84 , to lie in the depression  80  at the bottom of inner axial recess  52 . Pulling on the handset cable first end  106  causes the cord grip teeth  90  to securely grip the handset cable  18 .  
         [0050]    The ribbon cable first end  98  is led away from handset cable second end  96  in the depression  80  towards the curved vertical wall  108  of the inner axial recess  52 . The ribbon cable is then folded through 90° to lie flat against the wall  108 , being held there by a pin  110  which stands vertically from the floor of the inner axial recess  52 . A substantial portion of the ribbon cable  36  is then neatly coiled against the wall  108 , passing radially inwardly of the pin  110 , coiled in the same direction (clockwise as shown) as the handset cable  18  is coiled in the circumferential recess  50 . The remaining part of the ribbon cable  36  near its second end  38  passes into a longitudinal slot  112 , FIG. 4, formed in the hollow spindle  56 . This part of the ribbon cable  36  is pre-folded through 90° so as to pass up the interior of hollow spindle  56  to emerge from the free end thereof. The lid  54  is then snapped into place over the spool inner axial recess  52  and the spindle  56  free end. Finally the washer  62 , cover  26  and strain relieving outlet  34  are installed over the spindle  56  free end.  
         [0051]    As shown in FIG. 3, removal of the cover  26  also provides access to a spool brake mechanism  114  held captive between pairs of opposed flanges  115 ,  116 . To facilitate repair, mechanism  114  may be lifted out as a unit from between the flanges  115 ,  116  once the cover  26  has been removed.  
         [0052]    The spool braking mechanism  114  is shown in greater detail in FIGS.  8 - 10 . It comprises a pushbutton  22  that is slideably received in a hole  140  formed in a mounting block  141  received between the flanges  115 ,  116 . A compression spring  145  surrounding a shaft  138  of the pushbutton is received between the mounting block  141  and a shoulder  143  on the button. A toggle link  142  has a shaft  144  journalled in a hole  146  in block  141 . A braking cam  148  (see also FIGS. 9 and 10) has a shaft  150  journalled in a hole  152  in block  141 . A pin  143  of toggle link  142  is rotatably and slideably received in a slot  147  formed in cam  148 . A torsion spring  149  has one arm braced in a hole (not shown) in the mounting block  141  and another arm held by a tang  151  on the cam  148  to bias it clockwise and bring a braking surface  153  into contact with a rim  155  of the spool  48 . The radius of surface  153  increases in an anti-clockwise direction about shaft  150  as shown in FIG. 8. Handset cable  18  is drawn from and rewound onto the right hand side of the spool  48 , as indicated by arrow  137 . The cable passes through a smooth edged guide eye in block  141 , constituting the cable exit opening  16 . The cam braking surface  153  slides on the rim  155  to allow extension of the handset cable  18 , but is wedged against rim  155  to prevent spring  66  from rewinding the cable  18 .  
         [0053]    Latch means  154  comprising a lever  157 , a finger  159  and reset trigger  24  have a shaft  156  journalled in a hole  158  in the mounting block  141 . Finger  159  extends into an aperture  162  in block  141  that communicates with button shaft hole  140 . Lever  157 , finger  159  and trigger  24  are biassed outwardly towards the handset stowage recess  20  by a torsion spring  164  mounted on shaft  156  with one end braced in a groove (not shown) in the lower face of block  141  and another end received in a hole  166  in lever  157 .  
         [0054]    As shown in FIG. 9, when the button  22  is in its normal raised position, spring  164  holds the finger  159  against the rear of the lower end of button shaft  138  in the aperture  162 . Depressing the button  22  as in FIG. 10 causes the finger  159  to enter a detent groove  166  formed in the button shaft  138 , latching the button depressed. As the button  22  is moved downward towards its latched state, a depending foot  168  provided on a button lug  170  engages a cam surface  169  on the toggle link  42 , rotating the toggle link clockwise as shown in FIG. 8. Lugs  170 ,  172  slide in grooves (not shown) provided in the casing  12  to prevent the button  22  from rotating about its shaft  138 . The toggle pin  143  rotates the cam  148  anti-clockwise to bring its braking surface  153  out of contact with the spool rim  155 , allowing spring  66  to rewind the handset cable  18 . As the handset (not shown) is replaced in the stowage recess  20 , it presses against the trigger  24 , disengaging the finger  159  from the detent groove  166 , allowing the button  22  to pop up, releasing the cam  148  for contact between braking surface  153  and spool rim  155 .  
         [0055]    FIGS.  11 - 13  show an alternative spool brake mechanism. For ease of repair the mechanism components are mounted on pins  200 ,  202 ,  204 ,  206 ,  208 ,  210  moulded on the inside of the cover  26  (see FIGS. 3 and 11). The alternative brake mechanism thus may easily be supplied as a part of the repair kit comprising the wiring harness components  40 ,  36 ,  26 ,  62 ,  54 ,  100 ,  18 ,  102 ,  104 . The brake mechanism parts are moulded from a resilient, self-lubricating plastics material such as nylon and comprise a ratchet stop/index spring finger  212  secured on pins  200 ,  202  using Loctite® 406, a star/ratchet wheel  214  rotatably mounted on pin  204 , an oscillating pawl  224  rotatably carried on pin  206  and a centralising spring finger  216  secured on pins  208 ,  210  in similar manner to stop/index spring finger  212  and pins  200 ,  202 .  
         [0056]    The star/ratchet wheel  214  has six raised points  218  alternating with six troughs  220  about its periphery. It also has a raised hub with twelve peripheral ratchet teeth  222 , which are engaged by a shoulder on the end of the stop/index finger  212  so as to allow the star wheel to rotate, anticlockwise as shown, in twelve discrete steps, thereby alternately presenting a point  218  or a trough  220  to the oscillating pawl  224  at each rotational step. The stop/index finger  212  also acts to prevent rotation of the star/ratchet wheel  214  in the clockwise direction, and retains the wheel  214  on the pin  204 .  
         [0057]    [0057]FIGS. 12 and 13 show somewhat enlarged views of the top and underside of the oscillating pawl  224  respectively. Centralising spring finger  216  engages in a slot  226  to retain the oscillating pawl  224  on pin  206  and to return it to a rotationally centralised position with some degree of lost motion. An indexing spring arm  228  moulded in one piece with the oscillating pawl  224  engages the ratchet teeth  222  to index the star/ratchet wheel  214  anticlockwise by one step with each clockwise oscillation of the pawl  224 . The underside of the oscillating pawl  224  is provided with a projecting stop  230  which interacts with the star/ratchet wheel raised points  218  and troughs  220 . In the centralised position of the pawl  224 , depending upon the position of the star/ratchet wheel  214 , either a point  218  lies immediately in front of the stop  230 , thereby preventing anticlockwise rotation of the pawl  224 , or the stop lies within a trough  220  which provides sufficient clearance for anticlockwise rotation of the pawl  224  to a limit governed by the centralising spring finger  216 . In either position of the star/ratchet wheel  214 , the pawl  224  is free to rotate clockwise from the centralised position to a limit controlled by the centralising spring finger  228 .  
         [0058]    The oscillating pawl  224  carries a tooth  232  positioned to engage a series of teeth  234  upstanding axially from and circumferentially distributed about the spool  48  (see FIGS. 3, 5 and  7 ). Pulling on the handset cable will rotate the spool  48  clockwise relative to the inside of the cover  26  on which the brake mechanism is located (or anticlockwise in the spool chamber  46 , FIG. 3). This causes the spool teeth  234  to knock against the pawl tooth  232  in rapid succession, turning the pawl  224  clockwise in the reference frame of FIG. 11, and indexing the star/ratchet wheel  214  anticlockwise by one step or ratchet tooth  222 . Supposing that initially, before pulling on the cable, a point  218  lies immediately in front of the stop  230 . The oscillating pawl  224  cannot be rotated anticlockwise away from its centralised position in FIG. 11, which in turn means that the pawl tooth  214  engages one of the spool teeth  234 , preventing the spool from rotating anticlockwise relative to the inside of the cover  26 , so preventing the cable  18  from rewinding onto the spool under the influence of spring  66 . In this condition, pulling on the handset cable  18  will now index a trough  220  into co-operation with the pawl  224 , providing clearance for the stop  230 . Consequently, releasing the handset cable  18  will now cause it to rewind under the action of spring  66 , as the spool teeth  234  can knock aside the cam tooth  232 , rotating the oscillating cam  224  anticlockwise in the FIG. 11 reference frame. Pulling and releasing the handset cable  18  yet again will index a point  218  back into co-operation with the stop  230 , locking the spool against rewinding. In the result, with each successive pull and release, handset cable  18  is alternately free for, or locked against, retraction.  
         [0059]    It will be readily apparent that different numbers of points  218  and troughs  220  can be provided on the star/ratchet wheel  214  in place of the six shown. The main requirement is that the total number of points plus troughs should be equal to the number of ratchet teeth  222 .  
         [0060]    [0060]FIG. 14 shows a discrete cable reel which forms a second embodiment of the invention that may be mounted remotely from a handset cradle. It comprises a casing  12  in which is housed a spool assembly substantially identical to the assembly  40 ,  36 ,  62 ,  54 ,  48 ,  56 ,  66 ,  84 ,  100 ,  18 , of FIGS.  3 - 7 , further description of which is therefore superfluous. In place of cover  26 , there is a cover  252  secured to the casing  12  by screws  254 ,  256 . The casing  12  comprises a cable eye  258  in which the cable exit opening  16  is formed. Eye  258  is held in place between the remainder of the casingl 2  and the cover  252 . In place of the strain relief block  102  and multiplug  104 , the handset cable first end  106  carries a stop sleeve  260 . The ribbon cable strain relieving outlet  34  shown in FIG. 2 is replaced by a cap  262  snap-fitted into slots (not shown) in cover  252 . A spool braking mechanism substantially identical to mechanism  212 ,  214 ,  216 ,  224  of FIGS.  11 - 13  is mounted on pins moulded inside cover  252 , engaging teeth similar to teeth  234  formed on the spool. Further description of this mechanism is again superfluous.  
         [0061]    While the preferred embodiments and best mode of performing the invention have been particularly described and shown, the invention is not limited thereto and variation and modification of the illustrated embodiments will be readily apparent, within the scope and spirit of the invention as defined in the following claims.