Patent Publication Number: US-2011061982-A1

Title: Improved structure of single-pull composite wire reel

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention generally relates to a single-pull composite wire reel, aiming to provide a mechanism for one-way stretching or pulling of a composite wire comprised of a primary forward wire and a secondary spare, rotation-supporting wire, ensure mechanical strength of connection between the two wires, allow the rotation-supporting wire to be set in a from-outside-toward-inside wound condition to thereby allow the rotation-supporting wire to shrink from outside toward inside and to expand from inside toward outside for corresponding to the length of the primary wire required in extension and retraction thereof in order to significantly reduce the stretching and bending loads applied to the rotation-supporting wire and thus increasing the number of wire stretching and retracting of the wire reel and expanding the lifespan of the wire reel. 
     DESCRIPTION OF THE PRIOR ART 
     Wire reels are commonly used in electric/electronic devices, such as computer mousse, electrical connection boxes, or multi-port USB (Universal Serial Bus) connectors for winding/retracting or releasing/stretching a wire. The wire reels of this purpose available in the market are roughly divided as one-way stretching/retracting reels and two-way stretching/retracting reels. 
     Simply speaking, the one-way stretching/retracting reels allow a wire to be pulled outward or stretched in a single direction. The wire reel of this type is generally structured to allow a length of a wire at one side to be extendable and/or retractable, while another length (rotation-supporting wire) of the wire at an opposite side is fixed to connect with a power supply terminal. Thus, in the one-way stretching/retracting structure of wire reels, a given length of spare wire must be provided and generally concealed inside the reel, which is the key arrangement for effective operation of wire reels of this type. 
     For two-way stretching/retracting reels, wires can be extended and/or retracted in generally opposite directions. The wire reel of this type is generally structured to make two wires to be synchronously stretched and/or retracted. In the course of wire extension or retraction, the wire reel is generally located midway between the two wires. Generally speaking, a wire reel of this type is used to store, in an extendable/retractable manner, an extension cable of an external device, and there is generally no spare wire needed. Thus, the two-way wire reel is different from the one-way wire reel in both structure and field and purpose of application. 
     Further, in the known one-way stretching/retracting wire reel, a single wire is incorporated and the reel comprises a slide disk that defines a forward circumferential chamber and a backward circumferential chamber to respectively realize the mechanisms of wire stretching and rotation supporting, so that a single wire must provide a function for both forward and backward stretching/retracting. However, the rotation supporting wire must also be moved by a distance corresponding to the length of the forward wire that has been stretched or retracted in order to support further stretching and retracting of the forward wire and to realize the single-pull operation of the wire reel. 
     In the above described single-pull mechanism, the wire is arranged in multi-fold bending to properly set the orientation of the wire for making a length of the wire the rotation-supporting wire. This arrangement often leads to insufficient bending and force resistance at this point. It is particularly noted in a durability test, the wire is easy to break or dislocate at this point. Further, the rotation supporting wire is provided with a winding mechanism or means to allow it to wind in a regular manner and the winding is often quite random, leading entangling, overlapping, and twisting of the wire during the course of retracting. This not only requires an increase in the stretching strength of the forward wire and also makes bending point of the rotation supporting wire weaker, leading to easy twisting, folding, and quick aging and breaking. 
     Thus, to provide the highest quality, the best efficient, and the greatest convenience, the present invention aims to provide a single-pull composite wire reel that overcomes the above problems. 
     SUMMARY OF THE INVENTION 
     In view of the above described, the present invention provides a single-pull composite wire reel, which comprises a primary forward wire and a secondary rotation-supporting wire that are jointed and electrically connected to form a composite wire structure, in order to enhance the connection strength therebetween. Further, the rotation-supporting wire is set in a regular from-outside-toward-inside wound condition, so that the shrinkage and expansion of the rotation-supporting wire naturally show effort-saved operations of shrinking from outside-toward-inside and expanding from inside-toward-outside, whereby the stretching force that is applied by the primary forward wire can be reduced and the loads of stretching and bending that the rotation-supporting wire takes are lessened to thus increasing the number of wire stretching and retracting of the wire reel and expanding the lifespan of the wire reel. 
     The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
     Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a wire reel constructed in accordance with the present invention in a wound condition. 
         FIG. 2  is an exploded view of the wire reel of the present invention. 
         FIG. 3  is a top plan view of the wire reel of the present invention showing a positioning mechanism of the wire reel. 
         FIG. 4  is a schematic view showing connection between a secondary wire and a primary wire of the wire reel of the present invention. 
         FIG. 5  is a top plan view of the wire reel of the present invention with a top cover removed to show a wound condition of the secondary wire. 
         FIG. 6  is a cross-sectional view of the wire reel of the present invention in an assembled form. 
         FIG. 7  is a schematic view illustrating an application of the wire reel of the present invention to a computer mouse. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
     Referring to  FIGS. 1 and 2 , a single-pull composite wire reel constructed in accordance with the present invention comprises a positioning mechanism  1 , a top cove  2 , a wire fixing plate  3 , an inlay lid  4 , a coil spring  5 , a circuit board retention plate  6 , a circuit board  7 , a slide disk  8 , a secondary wire  9 , a primary wire  10 , and a bottom cover  11 . The coil spring  5  is received in an internal cavity  81  defined in the slide disk  8 . The coil spring  5  has a central terminal end fit into and retained by a central axle  110  formed on an inner side of the bottom cover  11  and an external terminal end forming a bend  52  that is fit into and engages a holding wall section  811  formed in the internal cavity  81 , whereby the slide disk  8  is subjected to constrain imposed by the coil spring  5 . Thus, rotation of the slide disk  8  in either a forward direction or a backward direction causes the slide disk  8  to be subjected to a tightening or releasing condition induced by the coil spring  5 , which serves as a primary force source for winding and returning the primary wire  10 . 
     As shown in  FIGS. 2 and 6 , the slide disk  8  defines a central bore  80  that receives the extension of the central axle  110  and also forms therein the internal cavity  81 , an upper cavity  82 , and a circumferential cavity  83  for respectively receiving and accommodating the coil spring  5 , the secondary wire  9 , and the primary wire  10  therein. The coil spring  5  that is received in the internal cavity  81  is covered and separated by the circuit board retention plate  6  and the internal cavity  81  is further closed by the inlay lid  4  for sealing, protection, and isolation, whereby the coil spring  5 , the circuit board  7 , and the secondary wire  9  are accommodated inside the slide disk  8  in sequence from the inside to the outside. 
     The secondary wire  9  and the primary wire  10  are jointed to each other and set in electrical connection with each other by the circuit board  7 , and additional arrangement can be made to joint and electrically connect the primary wire  10  and the secondary wire  9  that are of different wire gauges, as shown in  FIG. 4 . Further, the circuit board  7  is fixed atop the circuit board retention plate  6  to be separated from the coil spring  5  and to also provide the function of protection. The secondary wire  9  and the primary wire  10  that are jointed and electrically connected by the circuit board  7  respectively extend into the interior space of the upper cavity  82  of the slide disk and extend through a through hole  812  defined in a wall of the internal cavity of the slide disk  8  to be wound around the circumferential cavity  83  of the slide disk  8  so as to clearly define two different operation zones that allow the secondary wire  9  and the primary wire  10  to respectively carry out associated extension/retraction and stretching/returning. 
     As shown in  FIGS. 2 and 4 , the primary wire  10  and the secondary wire  9  are jointed and electrically connected by the circuit board  7 . When the primary wire  10  is pulled or stretched, due to the fact that the two wires are located in different operation zones, the primary wire  10  is completely free of dislocation or undesired dragging the secondary wire  9  into the operation zone of the primary wire  10 , which prevents the primary wire  10  from being completely wound. Further, the arrangement and positional relationship of the secondary wire  9  are set with the circuit board  7  as a starting point. Due to being guided by a slot  813  defined in an inside wall of the internal cavity  81 , the secondary wire  9  is allowed to extend into the upper cavity  82  of the slide disk  8  and set in a from-outside-toward-inside wound condition with a free end thereof extending through a fixing opening  31  defined in the wire fixing plate  3  at which a bend is formed to thereby allow the free end of the secondary wire  9  to extend out of the reel to serve as a power connection terminal  90  for an external device, such as a computer mouse, to which the windable wires are incorporated, as shown in  FIGS. 1 and 7 . 
     As shown in  FIGS. 2 and 5 , when the primary wire  10  is being stretched out, a rotational force is applied to the slide disk  8 , which induces a mechanical power stored in the coil spring  5 . Under this condition, the secondary wire  9  that is received in the interior space of the upper cavity  82  is caused to shrink from outside toward inside. In other words, the secondary wire  9  is shrunk inward to release a certain length for compensating the stretched length of the primary wire  10 . On the other hand, when the primary wire  10  is released and returns, the coil spring  5  releases the mechanical power stored therein to rotate and return the slide disk  8 . Under this situation, the secondary wire  9  is expanded from inside toward outside to resume the original loose state. The bend of the secondary wire  9  is fit to the wire fixing plate  3  fixed inside and under the top cover  2  and the fixing opening  31  and a wire receiving channel  32  defined in the wire fixing plate  3  leads the secondary wire  9  outwards, whereby the bend of the secondary wire  9  is kept stationary and is not moved with the rotation of the slide disk  8  or the secondary wire  9 . 
     As shown in  FIGS. 2 ,  3 , and  6 , the positioning mechanism  1  is set atop the top cover  2  and comprises a resilient catch plate  1 A and a resilient element  1 B. The resilient catch plate  1 A has an end pivoted to the top cover  2  and an opposite end bent to form a pawl  11 A extending into the top cover  2  and through a notch  33  defined in the wire fixing plate  3  to establish releasable engagement with an engagement recess  84  defined sideways in a top rim of the slide disk  8  located inside the top cover  2 . The resilient element  1 B provides a mechanical power for returning the resilient catch plate  1 A after it has been displaced by forming a moment of force about a center  11 B thereof, and has an end  12 B that is fixed and an opposite end serving as a force application end  13 B that is coupled to the resilient catch plate  1 A so as to induce a resilient returning operation on the resilient catch plate  1 A. Each time when the primary wire  10  is stretched outward to make a full turn of the slide disk  8 , due to the engagement induced with the engagement recess  84 , positioning is realized for one time. If the primary wire  10  has been stretched outward by a length to pass the engagement recess  84  of this current turn, then the positioning engagement may be realized at the next turn. In this way, multiple steps of positioning can be realized. When it needs to retract and return the primary wire  10 , the resilient catch plate  1 A is deformed outward to release the pawl  11 A from engagement with the engagement recess  84 , by which automatic rewinding and returning can be realized. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.