Abstract:
A mobile power tool stand includes two transverse bars for holding a power tool thereon, two first legs respectively pivoted to the transverse bars, two links respectively pivoted to the transverse bars, two second legs respectively pivoted to the first legs and the links for allowing the mobile power tool stand to be set between a received status where the first legs and the second legs are received together, and an extended status where the bottom ends of the first and second legs support the whole structure of the stand on the floor, and a locking structure for selectively locking the mobile power tool stand between the received status and the extended status.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a stand for power tool (such as table saw) and more particularly, to a mobile power tool stand that can conveniently be set between a received status and an extended status with less effort. 
     2. Description of the Related Art 
       FIG. 1  shows a stand  2  for supporting a table saw  1 . The stand  2  comprises a table board  3  to which the table saw  1  is fastened, a frame  4  fixedly fastened to the bottom side of the table board  3 , a first retaining device  4   a  provided at one side of the frame  4 , a pair of first legs  5  each having one end respectively pivoted to the frame  4 , and the other end provided with a second retaining device  5   a , a pair of second legs  6  respectively pivoted to the first legs  5 , a handle  6   b  fastened to one end of each of the second legs  6 , a locating pin  6   a  provided at each second leg  6  and spaced between the handle  6   b  and the pivoted joint between the first legs  5  and the second legs  6 , and a pair of wheels  7  respectively pivoted to the frame  4 .  FIG. 1  shows the stand  2  set in the extended status to support the table saw  1  in the operation position where the first retaining device  4   a  is fastened to the locating pin  6   a  at each second leg  6 .  FIG. 2  shows the stand  2  set in the received status where the first legs  5  and the second legs  6  are closely attached together, and the second retaining device  5   a  is fastened to the locating pin  6   a.    
     The aforesaid stand  2  is functional. However, when changing the stand  2  from the extended status shown in  FIG. 1  to the received status shown in  FIG. 2 , it requires the assistance of two persons to overcome the weight of the table saw  1 . If one person wishes to receive the stand  2  from the extended position, the person must have one leg stopped at the second legs  6  to provide a fulcrum, and then pull the handle  6   b  upwards to force the wheels  7  into contact with the floor. However, the table saw  2  and the stand  1  may fall to the ground suddenly if the person cannot bear the weight of the table saw  1  during the action of receiving the stand  2  to tilt the table saw  1 . Therefore, it is not recommended to receive the stand  2  by one person. 
     Further, because the second retaining device  5   a  lays open to the outside during the status shown in  FIG. 1 , a passing-by person may stumble over the second retaining device  5   a.    
     Therefore, it is desirable to provide a mobile power tool stand that eliminates the aforesaid drawbacks. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a mobile power tool stand, which is easy to operate and which is safe and stable in use. 
     To achieve this object of the present invention, the mobile power tool stand comprises two transverse bars for holding a power tool on a top side thereof; a pair of first legs each having a fulcrum respectively pivoted to the transverse bars; a pair of links each having a fulcrum respectively pivoted to the transverse bars; a pair of second legs each having a first pivot point respectively pivoted to the links and a second pivot point respectively pivoted to the first legs; a locking structure comprising a first locating member provided at the first legs, and a first retaining device provided at the second legs for fastening to the first locating member when the first legs are received to the second legs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing showing the extended status of a mobile table saw stand according to the prior art. 
         FIG. 2  corresponds to  FIG. 1  showing the received status of the mobile table saw stand. 
         FIG. 3  is a perspective view of a mobile power tool stand according to the present invention. 
         FIG. 4  is a side view of the present invention, showing a power tool supported on the extended status of the mobile power tool stand. 
         FIG. 5  is an exploded view of a part of the locking structure of the mobile power tool stand according to the present invention. 
         FIG. 6  is a schematic assembly view of  FIG. 5 . 
         FIG. 7  is a schematic side view of the present invention showing the extended status of the mobile power tool stand. 
         FIGS. 8-11  show the actions of the present invention from the extended status to the received status. 
         FIG. 12  is a perspective view showing the received status of the mobile power tool stand according to the present invention. 
         FIG. 13  is a schematic drawing of the present invention, showing the wheels moved with the mobile power tool stand on the floor. 
         FIG. 14  shows the received status of the mobile power tool stand with the grips and the wheels rested on the floor according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 3 , a mobile power tool stand  100  is shown alternatively settable between an extended status to support a power tool  200 , for example, a table saw as shown in  FIG. 4 , and a received status as shown in  FIG. 12 . 
     The mobile power tool stand  100  comprises a supporting structure  10 , a pair of first legs  20 , a pair of links  30 , a pair of second legs  40 , a locking structure  50 , a pair of wheels  60 , and an elevation adjustment unit  70 . 
     The supporting structure  10  comprises two transverse bars  12  and two grips  14 . The transverse bars  12  support the power tool  200 , each having a first end  121  and a second end  122 . The two grips  14  are respectively fixedly fastened to the first ends  121  of the transverse bars  12  and extending downwards. 
     The first legs  20  each have a top end provided with a first fulcrum  22  that is pivoted to one transverse bar  12  between the first end  121  and second end  122 , and a bottom end terminating in a first curved section  24  and a second curved section  26 , as shown in  FIG. 4 . The second curved section  26  is curving outwards and upwards. 
     The links  30  each are provided with a second fulcrum  32  respectively pivoted to the second ends  122  of the transverse bars  12 . 
     The second legs  40  each have a first pivot point  42  and a second pivot point  44 . The first pivot point  42  is pivoted to a middle part of one link  30 . The second pivot point  44  is pivoted to one first leg  20 . Further, one of the second legs  40  is provided with a first through hole  46  and a second through hole  48  for the mounting of the locking structure  50 . 
     Referring to  FIGS. 3 ,  5  and  6 , the locking structure  50  comprises a first locating member  51 , a first retaining device  52 , a biasing member  53 , a second locating member  54 , a second retaining device  55 , a guide pin  56 , and two pivot pins  57  and  58 . 
     The first locating member  51  is a beam connected between the first legs  20  to enhance the stabilization of the first legs  20 . 
     The first retaining device  52  comprises a footplate  521 , a first sideboard  522 , and a second sideboard  523 . The first sideboard  522  and the second sideboard  523  are respectively downwardly extending from two opposite lateral sides of the footplate  521 . The first sideboard  523  has a hook  524 , and a notch  525 , and a bevel edge  526 . Further, two first pivot holes  527  are respectively formed at the sideboards  522  and  523 ; a second pivot hole  528  is provided at the second sideboard  523 . The pivot pin  57  is inserted through the two first pivot holes  527  and the first through hole  46  to pivotally secure the first retaining device  52  to the second leg  40  having the said first through hole  46 . 
     The biasing member  53  is a torsional spring mounted on the pivot pin  57 , having a first end  531  fastened to the second leg  40  having the said first through hole  46  and a second end  532  fastened to the notch  525  of the first side board  523  of the first retaining device  52 . 
     The second locating member  54  is a beam connected between the rear ends of the links  30 . 
     The second retaining device  55  is an elongated plate member having a pivot hole  551  at one end, an elongated sliding slot  553  at the other end, and a hook  552  adjacent to the elongated sliding slot  553 . The pivot pin  58  is inserted through the pivot hole  551  of the second retaining device  55  and the second pivot hole  528  of the first retaining device  52  to pivotally secure the second retaining device  55  to the first retaining device  52 . 
     The guide pin  56  is inserted through the elongated sliding slot  553  of the second retaining device  55  and the second through hole  48  of the respective second leg  40  to guide movement of the second retaining device  55  linearly forwards/backwards. 
     The wheels  60  are respectively pivoted to the second legs  40  near the rear ends. 
     The elevation adjustment unit  70  comprises two first adjustment devices  72  respectively installed in the first legs  20 , and two second adjustment devices  74  respectively installed in the second legs  40 . Referring also to  FIG. 7 , each first adjustment device  72  comprises a screw rod  721 , which is threaded through the first curved section  24  of the respective first leg  20  and has a head  722  at the bottom side, and a locknut  73 , which is fastened to the screw rod  721  and rotatable to adjust the elevation of the head  722  of the screw rod  721  and to further correct the horizontal status of the mobile power tool stand  100 . The second adjustment device  74  has a screw rod  41  directly threaded into the bottom screw hole  40   a  of the respective second leg  40  and rotatable to correct the horizontal status of the power tool stand  100 . 
       FIG. 7  shows the extended status of the mobile power tool stand  100 . At this time, the hook  552  of the second retaining device  55  is hooked on the second locating member  54 , locking the mobile power tool stand  100  in the extended position. 
     The receiving operation of the mobile power tool stand  100  is described hereinafter with reference to  FIGS. 8-12 . When the user pressed the foot plate  521  of the first retaining device  52  with the foot, the second retaining device  55  is turned backwards to disengage the hook  552  from the second locating member  54  as shown in  FIG. 8 . At this time, the user can pull the grips  14  upwards to shift the center of gravity of the mobile power tool stand  100  to the first legs  20  and to simultaneously move the second legs  40  toward the first legs  20  due to the effect of the links  30 , enabling the second curved sections  26  of the first legs  20  to be supported on the floor.  FIGS. 11 and 12  show the second legs  40  almost closed to the first legs  20 . At this time, the bevel edge  526  of the first retaining device  52  touches the first locating member  51  at first to guide the hook  524  upwards. Thereafter, the first retaining device  52  is forced by the biasing member  53  to turn downward in clockwise direction and to further hook on the first locating member  51 . Thus, the parts of the mobile power tool stand  100  are prohibited from movement relative to one another. 
       FIG. 13  shows the mobile power tool stand  100  moved on the floor by means of the wheels  60 .  FIG. 14  shows the received status of the mobile power tool stand  100  with the grips  14  and the wheels  60  rested on the floor. By means of pulling the grips  14  vertically upwards, the user can easily lift the mobile power tool stand  100  from the position shown in  FIG. 14  to the position shown in  FIG. 13 . 
     During the process shown in  FIGS. 8-11 , the user can easily change the mobile power tool stand  100  from the extended status to the received status by oneself even if the mobile power tool stand  100  carries a power tool  200 . Further, because each first leg  20  has a first curved section  24  and a second curved section  26  connected in series, the user can gradually tilt the power tool  200 , preventing a sudden falling of the power tool  200 . Further, because the first retaining device  52  and second retaining device  55  of the locking structure  50  are provided at the middle part of the respective second leg  40 , they will not hinder any person around the mobile power tool stand  100 . Therefore, the mobile power tool stand  100  is safe, stable and convenient in use. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.