Patent Publication Number: US-2005115021-A1

Title: Office chair caster

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to an office chair caster, particularly to one capable of firstly having a first base and a second base oppositely joined together to form a wheel holder with a plurality of retaining pieces of the second base inserted into a plurality of fitting slots of the first base, further having a spindle extending through a spindle bore of a spindle seat, and then having the spindle seat inserted into through holes of the first base and the second base with a plurality of engagement protuberances of the spindle seat aligned with a plurality of engagement grooves of the second base, by which the spindle seat can be rotated at 90 degree to make the engagement protuberances of the spindle seat impelled over a plurality of projections that are disposed in an inner wall surface of the through hole of the first base, stopped by a plurality of stop blocks that are also disposed in the inner wall surface of the through hole of the first base, simultaneously engaged in a plurality of sliding slots of the second base, and thus limited between the projections and the stop blocks without moving further, thereby the spindle seat can be firmly fixed in the wheel holder to hold the spindle securely without worry of the spindle coming loose.  
      2. Description of the Prior Art  
      Generally speaking, a known conventional office chair caster  1 , as shown in  FIG. 1 , has an integrally-made wheel holder  10  whose upper portion is extended through by a spindle  11  that is provided with external threads and capable of being fixedly screwed to the wheel holder  10  by a nut  12 , and whose lower portion is pivoted with a wheel body  14  by a pivot  13 . However, such an office chair caster  1  designed to have the spindle  11  screwed to the wheel holder  10  by the nut  12  may become unsteady and noisy in rolling wheel body  14  because the nut  12  is liable to become loose after long-termed swiveling of the spindle  11 .  
     SUMMARY OF THE INVENTION  
      The main purpose of the invention is to offer an office chair caster being convenient in assembling and steady in rolling without worry of a spindle coming loose.  
      The main feature of the invention is to provide an office chair caster mainly including: 
          a wheel holder having a first base and a second base oppositely joined together;     the first base having a recess disposed thereon, an opening disposed at one side thereof, a rod housing disposed in an interior thereof and a cover plate integrally disposed at a lower portion thereof, the recess provided with a through hole disposed therein, the through hole provided with a plurality of fitting slots disposed on a wall thereof and extending therethrough in communication with the opening, the through hole also provided with a plurality of stop blocks oppositely disposed on an inner wall surface thereof and a plurality of projections oppositely disposed on the inner wall surface thereof;     the second base having a through hole disposed thereon, a plurality of retaining pieces protruded from one side thereof corresponding to the plurality of fitting slots of the first base, a rod housing disposed in an interior thereof corresponding to the rod housing of the first base and a cover plate integrally disposed at a lower portion thereof, the through hole provided with a plurality of sliding slots disposed on a wall thereof, each of the sliding slots located between every two of the retaining pieces and extending therethrough in communication with the side of the second base that is protruded with the plurality of retaining pieces, the through hole also provided with two engagement grooves oppositely disposed on an inner wall surface thereof, a connecting rod having both ends respectively fixed in the rod housings of the first base and the second base;     a wheel body capable of being mounted between the cover plates of the first base and the second base;     a spindle seat capable of being combined in the through holes of the first base and the second base, and having a flange disposed at an upper end thereof, a spindle bore disposed in a center thereof, and a plurality of engagement protuberances oppositely disposed on an outer wall surface thereof; and,     a spindle capable of being accommodated in the through holes of the first base and the second base and extending through the spindle bore of the spindle seat, the spindle having a stop flange disposed at a lower end thereof.       

    
    
     BRIEF DESCRIPTION OF DRAWINGS  
      This invention will be better understood by referring to the accompanying drawings, wherein:  
       FIG. 1  is a perspective view of a known conventional caster;  
       FIG. 2  is an exploded perspective view of an office chair caster in the present invention;  
       FIG. 3  is a perspective view of the office chair caster in the present invention;  
       FIG. 4  is a sectional view showing an assemblage of a wheel body of the office chair caster in the present invention;  
       FIG. 5  is a sectional view showing an assemblage of a first base and a second base of the office chair caster in the present invention, in which a spindle seat is in an unlocked condition;  
       FIG. 6  is a sectional view taken along section line A-A of the  FIG. 5 ;  
       FIG. 7  is a sectional view showing an assemblage of the first base and the second base of the office chair caster in the present invention, in which the spindle seat is rotated to be in a locked condition; and,  
       FIG. 8  is a sectional view taken along section line B-B of the  FIG. 7 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      A preferred embodiment of an office chair caster in the present invention, as shown in  FIGS. 2, 3  and  4 , mainly includes a wheel holder  2 , a wheel body  3 , a spindle seat  4  and a spindle  5 .  
      The wheel holder  2  has a first base  20  and a second base  21  oppositely joined together.  
      The first base  20  has a recess  200  disposed thereon, an opening  202  disposed at one side thereof, a rod housing  22  disposed in an interior thereof and a cover plate  23  integrally disposed at a lower portion thereof. The recess  200  is provided with a through hole  201  disposed therein. The through hole  201  is provided with a plurality of fitting slots  203  disposed on a wall thereof and extending therethrough in communication with the opening  202 . The through hole  201  is also provided with a plurality of stop blocks  204  oppositely disposed on an inner wall surface thereof and a plurality of projections  205  oppositely disposed on the inner wall surface thereof. The rod housing  22  has a rod hole  220  disposed therein. The rod hole  220  is provided with a circumferential ridge  221  protruded on an inner wall surface thereof. The cover plate  23  has an axle housing  230  disposed therein and provided with an axle hole  231  in which a circumferential ridge  232  protruded thereon.  
      The second base  21  having a through hole  210  disposed thereon, a plurality of retaining pieces  212  protruded at one side thereof corresponding to the plurality of fitting slots  203  of the first base  20 , a rod housing  24  disposed in an interior thereof corresponding to the rod housing  22  of the first base  20  and a cover plate  25  integrally disposed at a lower portion thereof. The through hole  210  is provided with a plurality of sliding slots  213  disposed on a wall thereof. Each of sliding slots  213  is located between every two of the retaining pieces  212  and extends therethrough in communication with the side that is protruded with the retaining pieces  212 . The through hole  210  is also provided with two engagement grooves  211  oppositely disposed on an inner wall surface thereof. The rod housing  24  has a rod hole  240  disposed therein. The rod hole  240  is provided with a circumferential ridge  241  protruded thereon an inner wall surface thereof. The cover plate  25  has an axle housing  250  disposed therein and provided with an axle hole  251  in which a circumferential ridge  252  protruded thereon. A connecting rod  26  having both ends respectively fixed in the rod housings  22 ,  24  of the first base  20  and the second base  21  and each of the ends is provided with a ring groove  260  thereon.  
      The wheel body  3  capable of being mounted between the cover plates  23 ,  25  of the first base  20  and the second base  21  has an axle hole  30  disposed therein for being passed through by a wheel axle  31 . The wheel axle  31  has both ends and each of the ends is provided with a ring groove  32  thereon.  
      The spindle seat  4  capable of being combined in the through holes  201 ,  210  of the first base  20  and the second base  21  has a flange  40  disposed at an upper end thereof, a spindle bore  42  disposed in a center thereof and a plurality of engagement protuberances  43  oppositely disposed on an outer wall surface thereof. The flange  40  is provided with at least one hole  41  disposed thereon.  
      The spindle  5  capable of being accommodated in the through holes  201 ,  210  of the first base  20  and the second base  21  and extending through the spindle bore  42  of the spindle seat  4  has a stop flange  50  disposed at a lower end thereof.  
      In assembling, referring to  FIGS. 2, 3 ,  4  and  5 , firstly have one end of the connection rod  26  inserted into the rod hole  220  of the rod housing  22  of the first base  20  with one of the ring grooves  260  of the connecting rod  26  engaged by the circumferential ridge  221  of the rod hole  220 .  
      Secondly, have one end of the wheel axle  31  inserted into the axle hole  231  of the cover plate  23  of the first base  20  with one of the ring grooves  32  of the wheel axle  31  engaged by the circumferential ridge  232  of the axle hole  231 .  
      Thirdly, have the wheel body  3  sleeved on the wheel axle  31 .  
      Fourthly, have the second base  21  oppositely joined together with the first base  20  with the wheel body  3  located between the cover plates  23 ,  25  of the first base  20  and the second base  21 , and then have another end of the wheel axle  31  inserted into the axle hole  251  of the cover plate  25  of the second base  21  with another one of the ring grooves  32  of the wheel axle  31  engaged by the circumferential ridge  252  of the axle hole  251 , thereby making the wheel body  3  firmly mounted between the cover plates  23 ,  25  of the first base  20  and the second base  21 .  
      Fifthly, have the retaining pieces  212  of the second base  21  inserted into the fitting slots  203  of the first base  20 , and then have another end of the connection rod  26  inserted into the rod hole  240  of the rod housing  24  of the first base  21  with another one of the ring grooves  260  of the connecting rod  26  engaged by the circumferential ridge  241  of the rod hole  240 , thereby making the first base  20  and the second base  21  oppositely joined together to form the wheel holder  2 .  
      Sixthly, have the spindle  5  upwardly extending through the spindle bore  42  of the spindle seat  4  from a lower end of the spindle bore  42  until the stop flange  50  of the spindle  5  is stopped by a bottom of the spindle seat  4 .  
      Seventhly, have the spindle seat  4  and the spindle  5  placed into the through holes  201 ,  210  of the first base  20  and the second base  21  of the combined wheel holder  2  with the engagement protuberances  43  of the spindle seat  4  aligned with the engagement grooves  211  of the second base  21 , as shown in  FIGS. 5 and 6 , and with the flange  40  of the spindle seat  4  placed in the recess  200  of the first base  20 .  
      Finally, have the hole  41  of the spindle seat  4  inserted by a tool to rotate the spindle seat  4  at 90 degree to make the engagement protuberances  43  of the spindle seat  4  impelled over the projections  205  of the through hole  201  of the first base  20 , stopped by the stop blocks  204  of the through hole  201  of the first base  21 , simultaneously engaged in the sliding slots  213  of the second base  21 , and thus limited between the projections  205  and the stop blocks  204  without moving further, as shown in  FIGS. 7 and 8 , thereby the spindle seat  4  can be firmly fixed in the wheel holder  2  to hold the spindle  5  securely without worry of the spindle  5  coming loose, by which an assemblage of the whole structure of the office chair caster in the present invention is completed, very convenient in assembling.  
      Moreover, the spindle  5  firmly held by the spindle seat  4  will not become loose and have longer use life so as to make the office chair caster steady in rolling without noise.  
      While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.