Patent Publication Number: US-2011048881-A1

Title: Expandable Shell of a Suitcase

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Chinese Utility Model Application No. 200920174026.2, filed on Aug. 26, 2009, the disclosure of which is herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a suitcase, more particularly to an expandable shell of a suitcase. 
     2. Description of the Related Art 
     A conventional suitcase generally includes a flexible expandable section which is displaceable between an expanded position for increasing the volume of the suitcase, and a retracted position where the flexible expandable section is folded and retained by a zipper. Thus, the volume of the suitcase can be varied by virtue of the flexible expandable section. However, no rigid structure is provided to support the flexible expandable section in the expanded position so that the structural strength of the suitcase is weak in use. Moreover, no adjusting means is provided for adjusting the volume of the flexible expandable section so as to meet the user&#39;s requirement. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an expandable shell of a suitcase which has sufficient structural strength and the volume of which is adjustable. 
     According to this invention, the expandable shell includes first and second surrounding shell bodies surrounding a longitudinal axis and configured to mate with and to be stackable on each other so as to cooperatively define an expandable accommodation chamber for increasing the volume of the suitcase. A pulling cord has an anchoring end secured to the first surrounding shell body, and a cord body which extends from the anchoring end to terminate at a connected end. A reel member is rotatably mounted to the second surrounding shell body, and is configured to permit the connected end to be secured thereon such that, by means of rotation of the reel member, the cord body is reeled in or out to shorten or lengthen a distance between the first and second surrounding shell bodies. The reel member has a flange which surrounds the reel axis and which is formed with a plurality of ratchet teeth that are angularly displaced from one another. A reel spring is disposed to bias the reel member to perform a reel-in movement. A pawl is movable relative to the reel member between a blocking position, where a retaining end of the pawl is engaged with one of the ratchet teeth so as to guard against a reeling-out movement of the reel member, and a free-rotating position, where the retaining end is disengaged from the reel member to permit the reel member to reel out the cord body. A pawl spring is disposed to bias the pawl to the blocking position. An extension spring is disposed to bias the second surrounding shell body away from the first surrounding shell body so as to enlarge the expandable accommodation chamber, and has a biasing force larger than that of the reel spring such that, once the pawl is moved to the free-rotating position, the second surrounding shell body is pushed away from the first surrounding shell body by the biasing force of the extension spring, while the cord body is permitted to be reeled out from the reel member against the biasing force of the reel spring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment of the invention, with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of the preferred embodiment of an expandable shell according to this invention in an expanded position; 
         FIG. 2  is a fragmentary sectional view of a guiding unit of the preferred embodiment taken along line II-II of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a control unit of the preferred embodiment; 
         FIG. 4  is a fragmentary plan view of the control unit in a blocking state; 
         FIG. 5  is a fragmentary plan view of the control unit in an operated state; and 
         FIG. 6  is a perspective view of the preferred embodiment when folded. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , the preferred embodiment of an expandable shell of a suitcase according to the present invention is shown to comprise a first surrounding shell body  10 , a second surrounding shell body  20 , a plurality of guiding units  30 , and two control units  40 . 
     The first surrounding shell body  10  is of a rectangular shape, and surrounds a longitudinal axis in a longitudinal direction. The first surrounding shell body  10  includes two first long walls  11  and two first short walls  12  interconnecting the first long walls  11 . 
     The second surrounding shell body  20  is substantially the same as the first surrounding shell body  10  and includes two second long walls  21  and two second short walls  22  interconnecting the second long walls  21 . The second surrounding shell body  20  surrounds the longitudinal axis and is disposed to mate with and to be stackable on the first surrounding shell body  10  so as to cooperate with the first surrounding shell body  10  to define an expandable accommodation chamber (A) for increasing the volume of the suitcase. 
     With reference to  FIG. 2 , each of the guiding units includes first and second mounting seats  31 , 32  respectively secured on the first and second long walls  11 , 21  and disposed opposite to each other in the longitudinal direction, first and second tubular members  33 , 34  which are respectively secured on the first and second mounting seats  31 , 32 , which extend in the longitudinal direction toward each other, and which are telescopically fitted to each other to forma tubular unit that is movable between retracted and extended positions, and an extension spring  35  which is disposed in the tubular unit to bias the second surrounding shell body  20  away from the first surrounding shell body  10  in the longitudinal direction and to urge the tubular unit toward the extended position so as to enlarge the expandable accommodation chamber (A). 
     With reference to  FIGS. 3 and 4 , each of the control units  40  includes a mount  41  secured to the second surrounding shell body  20 , a positioning mount  42  secured to the first surrounding shell body  10  and disposed opposite to the mount  41  in the longitudinal direction, a reel member  43  pivotably mounted on the mount  41 , a reel spring  44  mounted on the mount  41  and biasing the reel member  43  to perform a reel-in movement (R), a pawl  44  pivotably mounted on the mount  41  to engage the reel member  43 , a pawl spring  46 , a push button  47 , a button spring  48 , and a pulling cord  49 . 
     The mount  41  defines an accommodation space  411  and a slot  414 , and has an axle  412  disposed in the space  411  and extending along a reel axis that is transverse to the longitudinal direction, and a guide rail  413  extending in the longitudinal direction. 
     The positioning mount  42  has a retaining cavity  421  and a guiding slot  422  in spatial communication with the retaining cavity  421 . 
     The reel member  43  is received in the accommodation space  411 , is rotatably mounted on the axle  412 , and has a cord reeling portion  431 , and a flange  432  which surrounds the reel axis and which is formed with a plurality of ratchet teeth  433  that are angularly displaced from one another. 
     The reel spring  44  is a coil spring having two ends respectively secured on the axle  412  and the reel member  43 . The extension spring  35  has a biasing force larger than that of the reel spring  44 . 
     The pawl  45  has a retaining end  451  and a force-transmitting end  452 , and is pivotable between a blocking position, where the retaining end  451  is engaged with one of the ratchet teeth  433  so as to guard against a reeling-out movement (R′) of the reel member  43 , and a free-rotating position, where the retaining end  451  is disengaged from the reel member  43  to permit the reeling-out movement (R′) of the reel member  43 . The pawl spring  46  is a torsion spring disposed to bias the pawl  45  to the blocking position. 
     The push button  47  is mounted in the guide rail  413  and is manually operable to perform a stroke movement in the longitudinal direction so as to move the pawl  45  to the free-rotating position. 
     The button spring  48  is disposed between the mount  41  and the push button  47  to bias the push button  47  against the stroke movement. 
     The pulling cord  49  has an anchoring end  491  which is led into the retaining cavity  421  through the guiding slot  422 . A retained block  494  is connected to the anchoring end  491  and is received in the retaining cavity  421  so as to secure the anchoring end  491  in the retaining cavity  421 . The pulling cord  49  further has a cord body  493  which extends from the anchoring end  491  in the longitudinal direction to terminate at a connected end  492 . The connected end  492  is secured on the reel member  43  such that, by means of rotation of the reel member  43 , the cord body  493  is reeled in or out to shorten or lengthen a distance between the first and second surrounding shell bodies  10 , 20 . 
     Reference is made to  FIGS. 5 and 6  which illustrate the expandable shell of the suitcase in a non-expanded state, i.e., having a smallest volume. In this state, the second surrounding shell body  20  is stacked on the first surrounding shell body  10 , the extension spring  35  is in a compressed state, and a major portion of the cord body  493  is reeled in on the cord reeling portion  431 . 
     Referring again to  FIGS. 2 and 4 , when it is desired to extend the expandable shell to increase the volume of the suitcase, a pressing force is applied to the pushbutton  47  to actuate the force-transmitting end  452  of the pawl  45  so as to move the pawl  45  to the free-rotating position. The second surrounding shell body  20  can be pushed away from the first surrounding shell body  10  by the biasing force of the extension spring  35 , while the cord body  493  is permitted to be reeled out from the reel member  43  against the biasing force of the reel spring  44 . Once the pressing force is released from the push button  47  to result in engagement between the retaining end  451  of the pawl  45  and one of the ratchet teeth  433  of the reel member  43 , the reel-out movement (R′) of the reel member  43  is prevented so as to position the first and second surrounding shell bodies  10 , 20  in place. Thus, the volume of the expandable shell can be adjusted readily. 
     When it is desired to reduce the volume of the suitcase, the user can press the first and second surrounding shell bodies  10 , 20  toward each other against the biasing force of the extension spring  35 . By virtue of the biasing force of the reel spring  44 , the reel member  43  can perform a reel-in movement (R) to reel in the pulling cord  49 , and the ratchet teeth  433  can alternately slap against the retaining end  451  of the pawl  45  to provide audible and tactile feedback to the user until the tubular unit is placed in the retracted position as shown in  FIGS. 5 and 6 . If the user inadvertently releases the first and second surrounding shell bodies  10 , 20 , due to the engagement between the pawl  45  and the reel member  43 , relative movement between the first and second surrounding shell bodies  10 , 20  can be restricted. 
     As illustrated, the expandable shell according to this invention is extendable and retractable to adjust the volume of the suitcase. In addition, with the provision of the first and second surrounding shell bodies  10 , 20  and the guiding units  30 , the structural strength of the suitcase can be enhanced. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.