Patent Publication Number: US-10787346-B1

Title: Lift device for dust collection box of wood working machine

Description:
BACKGROUND OF THE INVENTION 
     1. Fields of the Invention 
     The present invention relates to a lift device for lifting or lowering a dust collection box relative to the working table of a wood working machine. 
     2. Descriptions of Related Art 
     The conventional wood working machine  1  as disclosed in  FIG. 1 , includes a working table  2  and a machining device  3  is installed to the working table  2  so as to proceed machining tasks to objects. 
     During machining the objects on the working table  2 , wood powder, debris and the like is generated and floats in the air. Therefore, a suction device (not shown) is used to suck the wood powder and debris. Yet the wood powder and debris around the machining device  3  cannot be sucked by the suction device, and a dust collection box  4  is used to collect the wood powder and debris around the machining device  3 . A vacuum machine  5  remove the powder and debris from the dust collection box  4  to keep clean around the machining device  3 . 
     The dust collection box  4  is connected to the underside of the working table  2  and is mounted to the machining device  3 . However, the dust collection box  4  has to be uninstalled from the underside of the working table  2  when the dust collection box  4  or the machining device  3  needs to be cleaned and has a maintenance. This requires one person to support the dust collection box  4  by hands, and the other person unscrews bolts to separate the dust collection box  4  from the working table  2 . It is difficult for doing this by only one person, because the dust collection box  4  may fall down to the floor. 
     The present invention intends to provide a lift device for lifting or lowering the dust collection box relative to the working table to eliminate the shortcomings mentioned above. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a lift device for a dust collection box of a wood working machine, and the lift device comprises a working table with a lift device connected to the underside of the working table. The lift device comprises a driving shaft unit, a passive shaft unit, a rotary unit, a break unit, a pulley unit and a cable unit. The driving shaft unit has a first seat, a second seat and a driving shaft, wherein the first seat and the second seat are fixed to the underside of the working table, and the driving shaft extends through the first seat and the second seat. The driving shaft has a first gear and a second gear mounted thereto. The passive shaft unit is connected to the underside of the working table. A third gear and at least two wheels are connected to the passive shaft unit. The third gear is engaged with the second gear. The rotary unit is connected to the driving shaft to rotate the driving shaft. The break unit has a break member and a resilient member. A control portion and a break portion are respectively formed on two ends of the break member. The break portion is pivotably connected to the first seat and has a rack formed thereto. The break member is pviotable between a break position and a loose position. The resilient member is connected between the first seat and the break portion so as to maintain the break member at the break position where the rack is engaged with the first gear to prevent the driving shaft from self-rotating. The pulley unit has multiple pulleys which are connected to the underside of the working table. The cable unit has at least two cables, and each cable has the first end fixed to the wheel corresponding thereto, and the second end of each cable reeves the pulley corresponding thereto and is connected with the connection portion corresponding thereto. 
     The primary object of the present invention is to provide a lift device which controls the height of the dust collection box to help the users to install and remove the dust collection box relative to the working table. 
     Another object of the present invention is to provide a lift device which maintains the dust collection box at a desired height to prevent the dust collection box from dropping to hurt people. 
     Yet another object of the present invention is to provide a lift device which allows one person to proceed the removal of the dust collection box from the working table. 
     The present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a conventional wood working machine; 
         FIG. 2  shows the dust collection box, the working table and the lift device of the present invention; 
         FIG. 3  is a side view to show the wood working machine with the lift device of the present invention; 
         FIG. 4  is an exploded view of the lift device of the present invention; 
         FIG. 5  is a perspective view to show the pivotal member of the positioning device of the lift device of the present invention; 
         FIG. 6  illustrates the lift device of the present invention; 
         FIG. 7  shows that the dust collection box is lifted or lowered by the lift device of the present invention; 
         FIG. 8  shows the cables are pulled upward by the lift device of the present invention; 
         FIG. 9  shows that the rotary unit is rotated to lift the dust collection box; 
         FIG. 10  shows that the dust collection box is lifted and the posts of the positioning unit extend through the holes of the dust collection box; 
         FIG. 11  shows that the pivotal members are pivoted to support on the flanges of the dust collection box; 
         FIG. 12  shows that the post is accommodated in the slots of the pivotal member, and 
         FIG. 13  shows that the dust collection box is lowered. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 2 to 13 , the lift device  100  for a dust collection box of a wood working machine of the present invention comprises a working table  10 , a dust collection box  20 , a lift device  30  and a positioning device  40 . 
     As shown in  FIGS. 2 and 3 , a machining device  91  is installed to the working table  10  so as to proceed machining to objects on the working table  10 . The working table  10  is supported on a base  92  which is put on the floor so that the working table  10  is located at a certain height. 
     As shown in  FIG. 2 , the dust collection box  20  is a box with an open top and multiple flanges  21  respectively extend from the top of four sidewalls of the dust collection box  20 . Each of two opposite flanges  21  has at least two connection portions  22  formed therein which are located symmetrically to each other. Each of the flanges  21  includes at least one hole  24  which is an elongate hole. Each of the at least two connection portions  22  of the dust collection box  20  includes a large bore  221 , a small bore  222  and a path  223 . The path  223  communicates between the large bore  221  and the small bore  222 , and the path  223  includes at least one turning portion and is an L-shaped path. The dust collection box  20  has a suction tube  23  connected to one sidewall thereof so as to be cooperated with a vacuum device  93  as shown in  FIG. 3  to suck the wood powder and debris from the dust collection box  20 . 
     As shown in  FIGS. 2 to 7 , the lift device  30  having a driving shaft unit  31 , a passive shaft unit  32 , a rotary unit  33 , a break unit  34 , a pulley unit  35  and a cable unit  36 . The driving shaft unit  31  has a first seat  311 , a second seat  312  and a driving shaft  313 . The first seat  311  and the second seat  312  are fixed to the underside of the working table  10 , and the driving shaft  313  extends through the first seat  311  and the second seat  312 . The driving shaft  313  has a first gear  314  and a second gear  315  mounted thereto. 
     The passive shaft unit  32  is connected to the underside of the working table  10 . The passive shaft unit  32  includes a third seat  321 , a fourth seat  322  and a passive shaft  323 . The third seat  321  and the fourth seat  322  are fixed to the underside of the working table  10 . The passive shaft  323  extends through the third seat  321  and the fourth seat  322 . A third gear  325  and at least two wheels  324  are connected to the passive shaft unit  32 . The third gear  325  is mounted to the passive shaft  323  and engaged with the second gear  315 . The at least two wheels  324  are fixed to the two ends of the passive shaft  323 . 
     The rotary unit  33  is connected to one end of the driving shaft  313  so that when rotating the rotary unit  33 , the driving shaft  313  is rotated. In this embodiment, the rotary unit  3  is a crank. 
     The break unit  34  includes a break member  341  and a resilient member  342 . A control portion  343  and a break portion  344  are respectively formed on the two ends of the break member  341 . The break portion  344  is pivotably connected to the first seat  311  and has a rack  345  formed thereto. The break member  341  is pviotable between a break position and a loose position. The resilient member  342  is connected between the first seat  311  and the break portion  344 . The resilient member  342  maintains the break member  341  at the break position where the rack  345  is engaged with the first gear  314  to prevent the driving shaft  313  from self-rotating. In this embodiment, the resilient member  342  of the break unit  34  is a spring. 
     The pulley unit  35  has multiple pulleys  351  which are connected to the underside of the working table  10 . 
     The cable unit  36  has at least two cables  361 , and each cable  361  has the first end fixed to the wheel  324  corresponding thereto, and the second end of each cable  361  reeves the pulley  351  corresponding thereto and is connected with the connection portion  22  corresponding thereto so as to be connected to the connection portion  22  of the dust collection box  20  corresponding thereto. The second end of the cable  361  extends through the large  221  and moves along the path  223  and is located within the small hole  222  so as to be connected to dust collection box  20 . 
     As shown in  FIGS. 2, 5 and 12 , the positioning device  40  includes multiple positioning units  41  pivotably connected to the underside of the working table  10 . Each positioning unit  41  includes a post  411  which includes the first end thereof (with threads) fixed to the underside of the working table  10 , and the second end of the post  411  of each positioning unit  41  is exposed beyond the underside of the working table  10 . A pivotal member  412  is pivotably connected to the underside of the working table  10 . The pivotal member  412  includes a plate  413 , a locking member  414  and a spring  415 . The plate  413  includes a support  416  bent from the top thereof. The support  416  includes an aperture  417  and a slot  418 , wherein the slot  418  communicates through a portion of the support  416  and a portion of the plate  413 . The locking member  414  includes the first end thereof (with threads) extending through the aperture  417  and fixed to the underside of the working table  10 , and the second end of the locking member  414  includes an enlarged end  419 . The plate  413  is located beside the post  411  with a distance between the plate  413  and the post  411 . The post  411  is located at the pivotal trace of the slot  418 . The spring  415  is mounted to the locking member  414  and biased between the enlarged end  419  and the support  416  so that when the pivotal member  412  is urged against the underside of the working table  10 . 
     When the dust collection box  20  is to be lifted by the lift device  30 , the user presses the control portion  343  of the lift device  30  as shown in  FIG. 8  by one hand, so that the break member  341  reacts against the force of the resilient member  342 , and the break member  341  changes from the break position to the loose position. The driving shaft  313  is not restricted by the break unit  34 . The user uses the other hand to rotate the crank  331  so as to rotate the driving shaft  313 , the second gear  315 , the third gear  325 , the passive shaft  323  and the wheels  324 . The wheels  324  rotate to scroll the cables  361  to lift the dust collection box  20  as shown in  FIG. 9 . 
     When the flanges  21  of the dust collection box  20  approach the underside of the working table  10 , the posts  411  extend through the holes  24  in the flanges  21  as shown in  FIG. 10 . When the user releases the control portion  343  of the break unit  34 , the user can move to another position to pivot the plates  413  as shown in  FIG. 11  to locate the supports  416  beneath the flanges  21  to support the dust collection box  20 . This allows the dust collection box  20  to be well supported and also reduces the weight that the cables  361  bear. After the plates  413  are pivoted, the posts  411  are located within the slots  418  as shown in  FIG. 12 . The force of the springs  415  restrict the plates  413  from self-rotating. 
     Besides, when cleaning the dust collection box  20  or maintaining the machining device  91 , the plates  413  are pivoted in the opposite direction and remove the supports  416  from the flanges  21 , and the posts  411  are separated from the slots  418 . The user then press the control portion  343  of the break unit  34  and rotates the crank  331  in opposite direction to lower the dust collection box  20  as shown in  FIG. 13 . 
     The present invention allows the user to easily lift or lower the dust collection box  20  without need of second person to help. During the processes, the user does not need to support dust collection box  20  by hands so as to protect the user. 
     Although in this embodiment, the rotary unit  3  is a crank, the driving shaft unit  31  may be cooperated with an electric motor and a gear box to rotate the driving shaft  313 . 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.