Abstract:
A movable table stand is mainly composed of a table stand and two locking members. The table stand includes four corner plates, four adjustable restrictive rods, two direction-free wheels and two auxiliary wheels set at preset positions. Each of the corner plates is formed integral, able to avert mistakes of secondary machining and enforce the whole strength. The locking members are respectively set at a preset position at two sides of the table stand and controlled to keep the table stand locked or unlocked by treading with a foot. Being independent from locking system, the direction-free wheels and the auxiliary wheels can be processed mechanically and simply, reducing cost and increasing marketing competition.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to a movable table stand, particularly to one including four corner plates formed respectively integral for enforcing the whole strength and locking members independent from wheels, reducing machining complexity.  
         [0003]     2. Description of the Prior Art  
         [0004]     Common conventional movable stand, as shown in  FIG. 1 , is mainly provided with four corner plates  1 , four adjustable fixing rods  2 , two direction-free wheels  3  and two auxiliary wheels  4 . Each of the corner plates  1  is formed of several plates welded together. The adjustable fixing rods  2  are respectively connected with one side of two corner plates  1 , assembled together with the corner plates to form a table stand. The direction-free wheels  3  and the auxiliary wheels  4  are set at preset positions around the table stand, enabling the table stand to move freely with a load on it. Additionally, the auxiliary wheel  4  is provided with a brake  5  so as to keep the table stand stopped steadily when the brake  5  is treaded by a foot. But, such a table stand, after having been used for a period of time, is easily damaged because of the degrading of the strength of the corner plates  1 . Also, because each of the corner plates  1  is formed of several plates, welding work is extra needed to finish it, increasing the manufacturing cost. And, the brake  5  of the auxiliary wheel  4  has to be pushed manually with a great force when the table stand is wanted to move, causing a very inconvenient operation. So this invention has been devised to improve the defects mentioned above.  
       SUMMARY OF THE INVENTION  
       [0005]     The prime object of this invention is to offer a movable table stand with a better structure.  
         [0006]     The main characteristics of the invention are two locking devices provided in a table stand. The table stand includes four corner plates, four adjustable restrictive poles, two direction-free wheels and two auxiliary wheels. Each of the corner plates is composed of a triangular bottom plate and two side plates extended up vertically from two sides of the bottom plate and formed integral, able to enforce the strength and save a secondary machining process and reduce the cost for competition in marketing. The locking members are respectively set at a preset position at two front sides of the table stand and independent from four wheels set around the table stand, with the manufacturing cost possible to be reduced. In addition, being controlled to keep the table stand locked or unlocked by treading with a foot, the locking members can be operated easily.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]     This invention is better understood by referring to the accompanying drawings, wherein:  
         [0008]      FIG. 1  is perspective view of a conventional movable stand;  
         [0009]      FIG. 2  is a perspective view of a preferred embodiment of a movable table stand in the present invention;  
         [0010]      FIG. 3  is a partial exploded perspective view of the preferred embodiment of a movable table stand in the present invention;  
         [0011]      FIG. 4  is a perspective view of the material of a gusset in the preferred embodiment of a movable table stand in the present invention;  
         [0012]      FIG. 5  is a perspective view of a locking member of the preferred embodiment in the present invention, showing it in an unlocking condition;  
         [0013]      FIG. 6  is perspective view of the locking member of the preferred embodiment in the present invention, showing the locking member in a locked condition; and  
         [0014]      FIG. 7  is a perspective view of the locking member of the preferred embodiment in the present invention, showing the locking member recovered from the locked condition to the unlocked condition. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]     As shown in  FIGS. 2 and 3 , a preferred embodiment of a movable table stand in this present invention includes mainly a table stand  10  and two locking devices  20 .  
         [0016]     The table stand  10  is composed of four corner plates  11 , four adjustable restrictive rods  12 , two direction-free wheels  13  and two auxiliary wheels  14 .  
         [0017]     The cover plate  11 , as shown in  FIG. 4 , possesses a triangular bottom plate  111  and two sideboards  112  extending up vertically from two sides of the bottom plate  111 . There are a preset number of fixing blocks  113  pressed at the conjunction of the bottom plate  111  and each side plate  112 . The top of each side plate  112  is pressed to form a fixing groove  114 . A fixing hole  115  is bored at a preset position of each side board  112 , to be threadably engaged with a quick disassembling bolt  15 , which is composed of a fixing bar  151 , an elastic spring  152 , a sleeve  153  and a washer  154 . A restrictive flange  155  is formed at a preset position in the intermediate portion of the fixing bar  151 . The elastic spring  152  is to be fitted restricted around the fixing bar  151 . Next, the fixing bar  151  is inserted into the sleeve  153 , with the elastic spring  152 , which is stopped by the restrictive flange  155 , and simultaneously confined in the sleeve  153 . Finally, the outer portion of the fixing bar  151  is screwed together with the washer  154 , keeping the fixing bar  151  confined in the sleeve  153  completely.  
         [0018]     The adjustable restrictive rod  12  bored with a preset number of fixing holes  121  corresponding to the quick disassembling bolt  15  is to be put in the inner side of the fixing block  113  and the fixing groove  114  of the corner plate  11 .  
         [0019]     The direction-free wheels  13  are respectively screwed pivotally at a preset front position of the corner plate  11  at the front portion of the table stand  10 .  
         [0020]     The auxiliary wheels  14  are respectively screwed pivotally at a preset position beside the corner plate  11  at the rear portion of the table stand  10 .  
         [0021]     The locking members  20  are fixed respectively at a preset position beside the corner plate  11  at the front portion of the table stand  10 , consisting of a bottom base  21 , a pedal  22 , a restrictive plate  23 , a fixing base  24  and an outer cover  25  respectively.  
         [0022]     The bottom base  21  is fixed at a preset position of the corner plate  11 , with the pedal  22 , the restrictive plate  23  and the fixing base  24  orderly connected pivotally with its outer side, and a fixing pivot  211  is fixed upright on the bottom base  21  in an intermediate portion.  
         [0023]     The pedal  22  has a pedal plate  221  extending from its rear end and formed with an arced surface  222  formed at an underside of its front-end section set with a restrictive projection  223  at a preset position. In addition, the pedal  22  is bored with a pivotal hole  224  in the front end section at a preset position for fitting with a double-head rivet  225  to be pivotally connected with the bottom base  21 . The double-head rivet  225  is matched with a twisting spring  226  fixed at the pedal  22  with its one end and the bottom base  21  with the other end.  
         [0024]     The restrictive plate  23  is provided with a fixing groove  231 , corresponding to the fixing pivot  211  of the bottom base  21 , and a locking surface  232  projecting on its upper side. In addition, the restrictive plate  23  is extended sidewise from its front to form a slope  233  and bored with a pivotal hole  234  at its rear end for fitting with a double-head rivet  235  to be pivotally connected with the bottom base  21 . The double-head rivet  235  is matched with a torsion spring  236  fixed at the restrictive plate  23  with its one end and the tail of the bottom base  21  with the other end.  
         [0025]     The fixing base  24  is bored with a pivotal hole  241  at its front end for fitting with a double-head rivet  242  to connect pivotally with the bottom base  21 . The double-head rivet  242  is matched with a torsion spring  236  fixed at the fixing base  24  with its one end and the bottom base  21  with the other end. In addition, from the bottom of the fixing base  24  is extended outwards and vertically a flat fixing plate  244  for fitting with a braking block  246  screwed together with a screw nut  245  at two sides of the fixing base  24  respectively.  
         [0026]     The outer cover  25  is to be covered on the pedal  22 , the restrictive plate  23  and the fixing base  24  and riveted with the two double-head rivets  225  and  235  of the pedal  22 , the restrictive plate  23  and the fixing base  24 .  
         [0027]     In using, as shown in  FIGS. 2 and 3 , the bottom plate  111  and the side plate  112  of each corner plate  11  are formed integral as one unit, providing a large strength for heavy loading. The direction-free wheels  13  can be moved in a controlled direction. As shown in  FIGS. 5 and 6 , they depict how the movable table stand in this invention is stopped steadily by the brake. First, the pedal  22  of each fixing member  20  must be treaded by foot to enable the arced surface  222  at the bottom of the pedal  22  to rotate against the double-head rivet  225  and the torsion spring  225 , then, to be compressed to sustain a rebounding force. By this time, the arced surface  222  is to enable the fixing base  224  beneath it to rotate against the double-head rivet  242  and the torsion spring  243  to be compressed to sustain a rebounding force. The fixing base  24 , after being rotated, is to keep the braking block  246  moved downwards so as to lift up the direction-free wheel  13  from the ground and stay steadily and immovable on the ground. Simultaneously, the restrictive projection  223  of the pedal  22  is to move along the locking surface  232  of the restrictive plate  23 , which is to rotate downwards against the double-head rivet  235  so as to compress the torsion spring  236  to sustain a rebounding force. When the restrictive projection  223  moves over the locking surface  232 , it will be restricted by the locking surface  232  and the slope  233 , achieving a steady stopping for the movable table stand in this invention.  
         [0028]     On the contrary, as shown in  FIG. 7 , if the movable table stand is to be moved, the pedal  22  must be treaded by foot to enable the restrictive projection  223  of the pedal  22  to move ahead slightly to the tip of the slope  233  of the restrictive plate  23  and further into the inner side of the slope  233 . By this time, because of the loosening of the torsion spring  236 , the restrictive plate  23  will rebound back to stay stopped owning to the fixing pivot  211  of the bottom base  21  fitting in and restricting the fixing groove  231 . Then, the pedal  22 , being no more restricted by the restrictive plate  23 , will rebound because of the loosening of the torsion spring  226 . Next, the fixing base  24  will as well rebound with its own rebounding force, enabling the braking block  246  to rise up from the ground and the wheels  13  to touch the ground and able to move.  
         [0029]     Finally, the advantages of the movable table stand are listed as below:  
         [0030]     1. Each of the corner plates  11  is formed as an integral unit, enforcing its strength, averting any mistake caused by secondary machining and to reduce the cost, enhancing practicality and marketing competition.  
         [0031]     2. Each of the locking members  20  is set at a preset position independently, able to reduce the machining complexity for the direction-free wheel  13  and the auxiliary wheel  14 , and is to control stopping and moving actions by direct treading with foot providing a convenient operation.  
         [0032]     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.