Abstract:
A reeling device is provided which allows an electrical lead to be wound up without the need for slip-rings. The lead is partially wound around a spool and is electrically connected to contacts in a spindle, about which the spool rotates. A portion of the lead is sprung and is loaded as the spool rotates to pay out the lead. A ratchet and pawl mechanism is provided to lock the lead in its extended configuration. The ratchet and pawl mechanism can be relased so that the lead is retracted using the energy stored in the sprung portion of the lead. 
     A pair of the reeling devices may be combined back-to-back to provide convenient storage for earpiece and plug leads for a headset. The reeling device may also be integrated into a portable electronic apparatus for storing earpiece or microphone leads.

Description:
This application is a continuation of Ser. No. 09/033,171, filed Mar. 2, 1998. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a reeling device for an electrical lead. 
     BACKGROUND TO THE INVENTION 
     It is known that it is desirable to be able to wind up electrical leads when they are not in use. A problem with reeling devices for electrical leads is that an electrical connection must be made to a lead on a rotating spool. The prior art solutions to this problem fall into two categories. In one category are devices which employ two coils of different diameters arranged such that as a lead is drawn from the large coil, the turns of the smaller coil can separate, e.g. U.S. Pat. No. 4,989,805. The other category comprises devices that use slip rings to make electrical connections to a lead on a spool, e.g. U.S. Pat. No. 5,339,461. 
     Devices in the first category have not established themselves in the marketplace and it is believed that this is because they have proved unreliable. Devices in the second category are unsuitable for small signal applications, for example microphone or headphone leads, because of noise caused by the slip ring contacts. 
     SUMMARY OF THE INVENTION 
     It is an aim of the present invention to overcome the afore-mentioned problems. 
     According to the present invention, there is provided a reel device comprising an elongate structure, providing a continuous electrically conducting path along substantially its whole length and including an electrical lead, a fixed spindle to which an end of the structure is fixedly connected and rotary means for winding the lead around the spindle for bringing the lead into a retracted configuration from an extended configuration. Thus, according to the present invention, there is no relative motion between one end of an electrical lead and the static portions of the reeling device. 
     The rotary means may comprise a rotatable disc with an aperture through which the lead extends such that as the disc is rotated, the lead is wound up or unwound. However, preferably, the rotary means comprises a spool onto which the lead is wound when the lead is in its retracted configuration. 
     Preferably, a releasable locking means is provided for locking the reeling device with the lead in an extended configuration. The locking means preferably comprises a ratchet and pawl mechanism, the ratchet being provided on the rotary means. However, the locking means may be in the form of a brake acting on the rotary means or the lead. 
     Preferably, a spring means is configured to drive the rotary means for retracting the lead from an extended configuration. More preferably, the spool is coupled to the spindle by a spring. The spindle is preferably coaxial with the spool and is conveniently within the spool. 
     Preferably, the afore-mentioned structure is integrated with the spring. In this case, the structure may comprise a flexible conductor mounted to the spring. However, the flexible conductor may merely follow the path of the spring, e.g. between the coils of the spring, without being attached thereto or being unattached along a substantial portion of the length of the spring. More preferably, the conductor and the spring are embedded together in a flexibly resilient polymeric material. An alternative is to use a polymeric spring, for example formed from polycarbonate, and form conductive foil tracks on the spring in the manner of a printed circuit board. 
     The present invention is particularly useful where the lead is to carry small signals such as those to headphones or from microphones. 
     Conveniently, a device according to the present invention may be mounted in an electronic data processing apparatus or in connection with a headset. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of a device according to the present invention; 
     FIG. 2 is a plan view of the device of FIG. 1 with its spring cover removed; 
     FIG. 3 is a cross-sectional view of the sprung portion of the lead of the device of FIG. 1; 
     FIG. 4 is a detail view showing the lead as it passes through the spool of the device of FIG. 1; 
     FIG. 5 is a detail view of the spindle of the device of FIG. 1; 
     FIG. 6 shows a portable computer including a device according to the present invention; 
     FIG. 7 shows a headset including a device according to the present invention; and 
     FIG. 8 shows a dual reel device according to the present invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings. 
     Referring to FIGS. 1 and 2, which are intended to assist the reader in achieving a general understanding of the present invention rather than illustrate a particular application, a fixed spindle  1  projects from a chassis member  2 . The chassis member  2  projects perpendicularly from a first case member  3  and lies parallel to a second case member  4 . An arcuate wall  5  projects upwardly from the chassis member  2 , defining together with the first case member  3 , a space in which a rotatable spool  6  is located. 
     The spool  6  comprises parallel spaced first and second annular flanges  7 ,  8  connected by an open-ended cylindrical member  9 . The spool  6  is coaxial with the spindle  1 . The first flange  7  has a ratchet formed in its radially outer margin. A spring biased pawl  10  is located between the spool  6  and the first case member  3  and engages the ratchet on the spool  6 . A push button  11  extends through the first case portion  3  and bears against the pawl  10 . When the push button  11  is depressed, the pawl  10  is released from the ratchet. 
     A pair of flexible leads  12 ,  13  are wound around the spool  6 . The proximal ends of the flexible leads  12 ,  13  are coupled to one end of a sprung lead  14  coiled within the spool  6 . The other end of the sprung lead  14  is fixed to the spindle  1 . The spindle  1  is provided with electrical contacts for providing electrical connections to signal carrying parts of the sprung lead  14 . 
     A cover  15  is retained over the sprung lead  14  by a latch on the spindle  1 . 
     Referring to FIG. 3, the sprung lead  14  comprises a strip  16  of spring steel, a first braided conductor  17  to one side of the strip  16  and a second braided conductor  18  to the other side of the strip  16 . The strip  16  and the braided conductors  17 ,  18  are embedded in flexible polymeric material  19  to form a structure which is itself an elongate strip. The amount of polymeric material used should be kept to a minimum consistent with structural integrity and ensuring isolation between the steel strip  16  and the braided conductors  17 ,  18 . 
     Referring to FIG. 4, the sprung lead  14  has a short portion extending through a slot  20  in the spool  6 . A plug  21  is mounted to the end of the sprung lead  14 . The plug  21  has pins (not shown) connected to respective braided conductors  17 ,  18 . An inline socket  22  is connected to the proximal ends of the leads  12 ,  13  and is adapted to receive the plug  21  to establish an electrical connection between the braided conductors  17 ,  18  and the leads  12 ,  13 . 
     The plug  21  is provided with latch members  23  which engage with the socket  22  to lock the plug  21  and the socket  22  together. 
     The socket  22  is provided with an enlarged portion  24  to prevent it being drawn through the slot  20 . 
     Referring to FIG. 5, the spindle  1  is generally cylindrical and is provided with a reduced diameter portion  30  at its distal end. The reduced diameter portion  30  is provided with flexible tangs  31  for retaining the spring cover  15 FIG. 1) in place. A socket  32  with a radial opening is formed in the spindle  1 . The socket includes first and second electrical contact pins  33 ,  34 . 
     The inner end of the sprung lead  14  is provided with a plug  35  for cooperation with the socket  32 . The plug  35  includes contacts for receiving the pins  33 ,  34  and latching members  36  for retaining it in the socket  32 . The spring steel strip  16  of the sprung lead  14  extends into the plug  35  such that, when the plug  35  and socket  32  are united, the strip  16  extends into the spindle  1  thereby reinforcing the connection between the sprung lead  14  and the spindle  1 . 
     The operation of the reeling device of FIGS. 1 to  5  will now be described. 
     In an initial condition, the leads  12 ,  13  are full wound around the spool  6  and the sprung lead  14  is fully relaxed, in which condition most of its turns are located at or close to the inner surface of the cylindrical member  9  of the spool  6 . If the leads  12 ,  13  are now pulled, the spool  6  will rotate. As the spool  6  rotates, the sprung lead  14  is wound further around the spindle  6 , increasing the number of turns about the spindle  1  and causing the turns to move away from the inner surface of the cylindrical member  9  towards the spindle  1 . In other words, the sprung lead  14  is wound more tightly about the spindle  1 . If the force on the leads  12 ,  13  is now removed, the sprung lead  14  will attempt to relax and rotate the spool  6  in the other direction. However, the spool  6  is prevented from rotating by the rachet and pawl  18 . 
     If a user wished to retract the leads  12 ,  13 , the user presses the push button  11 , releasing the ratchet and pawl mechanism and allowing the spool  6  to rotate under the influence of the sprung lead  14 . The rotation of the spool  6  winds in the leads  12 ,  13 . 
     Referring to FIG. 6, a portable computer  40  comprises a main body portion  41 , lid  42  hingebly coupled to the main body portion  41 , a screen  43  on the lid and a base panel  44  hingebly coupled to the main body portion  41 . The base of the main body portion  41  is revealed when the base panel  44  is opened and is provided with channels  45  for receiving a light-weight headset  46  for storage. The headset  46  comprises earphones  47  and a microphone  48 . 
     The headset  46  is electrically coupled to the computer  40  by a lead  49 . The lead  49  is stored on a reeling device similar to that shown in FIGS. 1 to  5  which is located in the main body portion  41 . The lead  49  can be retracted by depressing a button  11 . The reeling device differs from that described above in that the lead  49  is guided through 90° so that it emerges through the base of the main body portion  41 . The base panel  44  has a cut-out  50  so that it can be closed when the headset  46  in use. 
     Referring to FIG. 7, a headset  70  comprises first and second earpieces  71 ,  72 . The earpieces  71 ,  72  are connected by respective leads  73 ,  74  to a housing  75 . The housing  75  contains a reeling device similar to that shown in FIGS. 1 to  5  and the leads  73 ,  74  are connected to contact pins in the spindle thereof. A lead  76  is stored on the spool of the reeling device and is provided with a jack plug  77  at its free end. 
     Referring to FIG. 8, two reeling devices as shown in FIGS. 1 to  5  are contained in a single cylindrical housing  80 . The spools of the reeling devices are coaxially arranged one beside the other and electrical connections are made between the respective spindles. 
     A lead  81  is stored by one of the reeling devices and is terminated at its distal end by a small jack plug  82 . A pair of leads  83 ,  84  are stored by the other reeling device and have respective earpieces  85 ,  86  attached to their distal ends. 
     The housing  80  is provided with a projection  87  having an aperture for receiving the jack plug  82  when it is not in use. The housing  80  is also provided with a pair of recesses  88 ,  89  configured to receive and retain the earpieces  85 ,  86 . 
     A cord  90 , a chain or the like is attached to the housing  80  so that the device may be worn around the neck by a user. 
     A device as shown in FIG. 8 provides a convenient storage device for the leads used with a personal stereo. 
     In a further embodiment, a reel device according to the present invention is contained in a unit adapted to be mounted to a standard personal computer disk drive mounting. 
     In a still further embodiment, a reel device is as described with reference to FIGS. 1 to  5  save that the electrically conductive path is replaced by and optical waveguide, including an optical fibre, and optical connectors replace electrical connectors. In this embodiment, care must be taken to ensure that coiling of the optical waveguide does not result in significant light loss due to the breakdown of the conditions for total internal reflection. 
     It will be appreciated that many electrical components or devices, e.g. tools and optical transmitters and receivers, may be attached to the lead of a reeling device according to the present invention. 
     It will be appreciated that many modifications may be made to the exemplary embodiments described hereinbefore. It will also be appreciated that a slip-ring free reeling device may be used advantageously in many situations where slip-ring noise is undesirable.