Patent Publication Number: US-2011067202-A1

Title: Truckle

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to a truckle, and particularly to a truckle which either limits direction solely or limits direction and rotation simultaneously. 
     (b) Description of the Prior Art 
     A conventional truckle substantially comprises a base and a wheel pivoting to the base. An arresting unit is disposed between the base and the wheel. The arresting unit is a metal plate attached to the wheel. A shaft is provided on an end of the base for assembling the truckle to a bottom of a carried object. The wheel rotates to move the object, and at the same time, the shaft brings the base to rotate the wheel in multi-directions. As the object arrives at a target position, the arresting unit presses the wheel to stop. 
     The wheel of the conventional truckle can be pressed to limit its rotation. However, the truckle only limits rotation of the wheel but fails to determine direction of the wheel while arresting. Once the wheel is arrested, the truckle may change direction by the shaft. The truckle cannot limit rotation and direction effectively, thus can not meet practical requirement. 
     SUMMARY OF THE INVENTION 
     To obviate the above drawback, accordingly, an object of the present invention is to provide a truckle which either limits direction solely or limits direction and rotation simultaneously and which has a firm structure and can be reliably arrested. 
     To achieve the above object, the truckle of the present invention comprises a swiveling shaft, a rack, a driving unit received in the swivel shaft, and an arresting unit assembled with the driving unit. The swiveling shaft defines a through hole near an end thereof, and has a bearing on another end thereof. The rack has an end connecting with the bearing, and a wheel is movably assembled on another end of the rack. A plastic shell envelops the rack. A projection extends from an inward surface of the rack. A latch portion is formed on an inward surface of the plastic shell. The driving unit includes a rotating member corresponding to the through hole, a push member corresponding to a peripheral of the rotating member, a sleeve telescopically mounted on the push member, and a resilient member on the sleeve and abutting the push member. The arresting unit includes an axis pole, a gear disc mounted on the axis pole for corresponding to the latch portion, and an arresting block mounted below the gear disc and corresponding to the wheel. The axis pole extends into the sleeve for assembling with the push member. A slot is defined in the gear disc for corresponding to the projection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a truckle according to the present invention. 
         FIG. 2  is an exploded view of the truckle of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the truckle while rotating. 
         FIG. 4  is a cross-sectional view of the truckle while limiting direction. 
         FIG. 5  is a cross-sectional view of the truckle while limiting direction and rotation. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 ,  2  and  3 , a truckle in accordance with the present invention comprises a swiveling shaft  1 , a rack  2 , a driving unit and an arresting unit  4 . 
     The swiveling shaft  1  comprises a first casing  11  and a second casing  12  assembled together. A through hole  13  is defined near an end of the swiveling shaft  1 . A bearing  14  is provided on another end of the swiveling shaft  1 . 
     The rack  2  has an end connecting with the bearing  14 . A wheel  21  is movably assembled on another end of the rack  2 . The wheel  21  has a central shaft  211  movable pivoted on the rack  2 , and side covers  212  on opposing sides thereof. A plastic shell  22  envelops the rack  2  for protecting against erosion, ornamenting the rack  2 , and shielding from static. A projection  23  extends from an inward surface of the rack  2 . A latch portion  24  is formed on an inward surface of the plastic shell  22 , and forms a dental portion  241  on a side thereof. 
     The driving unit  3  is received in the swiveling shaft  1 , and comprises a rotating member  31  corresponding to the through hole  13 , a push member  32  corresponding to a peripheral of the rotating member  31 , a sleeve  33  telescopically mounted on the push member  32 , and a resilient member  34  on the sleeve  33  and abutting the push member  32 . A first cutout  311  and a second cutout  312  are respectively defined on a peripheral of the rotating member  31 . A flange  313  is formed on a peripheral of the rotating member  31 . A driving pin  5  extends through the through hole  13  and is mounted on the rotating member  31 . 
     The arresting unit  4  is assembled with the driving unit  3 , and comprises an axis pole  41 , a gear disc  42  mounted on the axis pole  41  for corresponding to the latch portion  24 , and an arresting block  43  below the gear disc  42  and corresponding to the wheel  21 . The axis pole  41  extends into the sleeve  33  for assembling with the push member  32 . A slot  421  is defined in the gear disc  42  for corresponding to the projection  23 . The arresting block  43  forms a barbed surface  431  on a side thereof and corresponding to the wheel  21 . 
     Further referring to  FIGS. 3 ,  4  and  5 , in use, the swiveling shaft  1  is assembled on a bottom of a carried object (not shown). As shown in  FIG. 3 , when the object is moved, the push member  32  of the driving unit  3  abuts against the second cutout  312  of the rotating member  31 . The gear disc  42  and the arresting block  43  of the arresting unit  4  are separate from the latch portion  24  and the wheel  21 . The rack  2  and the wheel  21  are free to rotate and change direction. 
     The driving pin  5  extends through the through hole  13  of the swiveling shaft  1  and is mounted on the rotating member  31 . In order to limit direction of the truckle solely, the driving pin  5  drives the push member  32  to abut against the first cutout  311  of the rotating member  31 . The axis pole  41  moves up with the resiliency of the resilient member  34 . The gear disc  42  is brought to abut against an inward surface of the rack  2 . The projection  23  is embedded into the slot  421  of the gear disc  42 , positioning the rack  2  and limiting direction of the truckle, as shown in  FIG. 4 . 
     In order to limit direction and rotation of the truckle at the same time, the driving pin  5  rotates the rotating member  31 . The flange  313  of the rotating member  31  abuts against the push member  32 . The axis pole  41  moves downward and presses the resilient member  34 . The gear disc  42  and the arresting block  43  move down. The gear disc  42  meshes with the dental portion  241  of the latch portion  24 . The barbed surface  431  of the arresting block  43  retain the wheel  21  firmly, positioning the rack  2  and the wheel  21  and limiting direction and rotation of the truckle, as shown in  FIG. 5 . 
     As described above, the truckle of the present invention can either limit direction thereof solely or limit direction and rotation simultaneously. In addition, the truckle has firm structure and can be arrested reliably. 
     It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.