Patent Publication Number: US-2010120339-A1

Title: Dust collection device for sanding machine

Description:
FIELD OF THE INVENTION 
     The present invention relates to a dust collection device for a sanding machine and the sanding belt, fan unit and the sanding wheel are co-rotated with a common axle so as to efficiently collect dust during work. 
     BACKGROUND OF THE INVENTION 
     A conventional sanding machine includes a support frame which has right and left frame walls opposite to each other in a longitudinal direction to confine a receiving space, and a mounting wall disposed between the frame walls and extending in the longitudinal direction. A power unit includes a motor which has an output shaft to drive an active wheel, a passive wheel and a transmission belt connected between the active and passive wheels. 
     A sanding member is horizontally installed and includes two parallel side panels between which two rollers are located, an emery coated belt is trained on the two rollers. An axle extends through the lower roller and driven by the motor so that the top roller is rotated. An emery coated belt is driven by the rotation of the two rollers and moves toward one direction. 
     When sanding a workpiece, the motor is first activated so as to drive the rollers and the emery coated belt rotates at a preset speed, the user holds the workpiece which is moved to be in contact with the emery coated belt to remove surface material of the workpiece. During operation, dust flies randomly and can cause serious health problem to the users. 
     The present invention intends to provide a dust collection device for a sanding machine which includes an axle which drives the sanding belt, the fan unit and the sanding wheel simultaneously, the dust is guided downward into the dust collection part and the shortcoming of the conventional sanding machine can be improved. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a sanding machine and comprises a base unit including a base which has a space and a board is mounted on an open top of the base. A frame extends upward from the board. A first slot and a second slot are defined through the board and communicate with the space. An axle extends through the frame. A sanding unit includes first and second side panels and a top roller and a lower roller are located between the first and second panels. A sanding belt is trained on the top roller and the lower roller. A casing accommodates the lower roller and a part of the sanding belt, and a bottom hole is defined through a bottom of the casing and communicates with the second slot. A guide member is located beside the bottom hole. A power unit includes a motor in the space and an active pulley which is driven by the motor, a passive pulley is driven by the active pulley by a transmission belt trained on the active and passive pulleys. The axle extends through the passive pulley and a first end of the axle is connected to the lower roller and a second end of the axle is connected to a fan unit and a sanding wheel. 
     A dust collection device includes a dust collection part, a hollow hose, an outer cover, the fan unit, a separation plate, the sanding wheel and a housing. The dust collection part has an open top which is located in alignment with the second slot. A tube and an outlet are located in communicating with the open top of the dust collection part. The hollow hose has a first end connected to the tube. The outer cover is connected to the base unit and the axle extends through the outer cover. A shoulder is formed on an inside of the outer cover and an air inlet is defined through the shoulder. The shoulder is located along a periphery of a concaved chamber defined in the inside of the outer cover. A main-air-outlet and a sub-air-outlet are located in communication with the concaved chamber. A second end of the hollow hose is connected with the sub-air-outlet. An escape pipe has a first end engaged with the main-air-outlet. 
     The axle extends through the fan unit and the separation plate is engaged with the concaved chamber. The separation plate includes a path, a guide plate, a first hole, a second hole and a suction opening, wherein the path is located in communication between the air inlet of the outer cover and the first and second holes and the suction opening. The guide plate is located beside the suction opening and a distal end of the guide plate contacts a peripheral wall of the over cover. The air inlet of the outer cover is located in communication between the outlet of the dust collection part and the path of the separation plate. 
     The sanding wheel is mounted to the axle and located between the separation plate and the housing. The housing has a pressing plate extending from an inside thereof so as to define an exterior collection area between the housing, the outer cover and the separation plate. A part of the sanding wheel is located within the exterior collection area. 
     The present invention will become more obvious 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  is an exploded view to show the sanding machine of the present invention; 
         FIG. 2  is an enlarged exploded view to show some parts in  FIG. 1  of the sanding machine of the present invention; 
         FIG. 3  is a cross sectional view of the sanding machine of the present invention; 
         FIG. 4  shows the outer cover connected to the base and the parts within the outer cover of the sanding machine of the present invention; 
         FIG. 5  shows that the fan unit is connected to the outer cover of the sanding machine of the present invention; 
         FIG. 6  shows that the separation plate is connected to the outer cover of the sanding machine of the present invention; 
         FIG. 7  shows that the sanding wheel and the housing separation are connected to the outer cover of the sanding machine of the present invention; 
         FIG. 8  is the bottom view to show the connection of the sanding wheel and the housing separation connected to the outer cover of the sanding machine of the present invention; 
         FIG. 9  is a cross sectional view, taken along line A-A in  FIG. 7 , and 
         FIG. 10  shows another embodiment of the casing with an upright guide member. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 to 10 , the present invention provides an improved dust collection device for a sanding machine which comprises a base unit  1  including a base  10  and a board  15  which is mounted on an open top of the base  10 . A space  18  is defined in the base  10  and communicates with the open top of the base  19  and a frame  153  extends upward from the board  15 . A first slot  151  and a second slot  152  are defined through the board  15  and communicate with the space  18 . An axle  34  extends through the frame  153  and two ends of the axle  34  protrude from two sides of the frame  153 . 
     A sanding unit  2  includes first and second side panels  21 ,  22  and a top roller  23  and a lower roller  24  are located between the first and second panels  21 ,  22 . A sanding belt  25  is trained on the top roller  23  and the lower roller  24 . A first end of the axle  34  is connected to the lower roller  24  so as to drive the top roller  25  to move the sanding belt  25  toward one direction. A casing  26  accommodates the lower roller  24  and a part of the sanding belt  25 , and a bottom hole  2611  is defined through a bottom of the casing  26 . The bottom hole  2611  is located in alignment with the second slot  152 . A guide member  265  is located beside the bottom hole  2611  and extends inclinedly relative to a vertical plane which is not shown. A rear cover  4  is connected between a top of the base unit  1  and a lower end of the casing  26  of the sanding unit  2 , the rear cover  4  includes an opening  41  which is located in alignment with the bottom hole  2611  of the casing  26  and the second slot  152  of the base unit  1 . The casing  26  includes a first part  261  having a hole (not shown) and a second part  262  having another hole (not shown) so that the axle  34  extends through the two respective holes. The bottom hole  2611  is defined through the first part  261  and the guide member  265  is located on the first part  261 . An end of the guide member  265  protrudes beyond the surface of the first part  261  so that the bottom hole  2611  is in alignment with the second slot  152 . 
     A power unit  3  includes a motor  31  located in the space  18  and an active pulley  32  which is driven by an output shaft  311  of the motor  31 . A passive pulley  33  is driven by the active pulley  32  by a transmission belt  35  trained on the active and passive pulleys  32 ,  33 . The axle  34  extends through the passive pulley  33  and a second end of the axle  34  is connected to a fan unit  53  and a sanding wheel  55 . 
     The dust collection device includes a dust collection part  50 , a hollow hose  51 , an outer cover  52 , the fan unit  53 , a separation plate  54 , the sanding wheel  55  and a housing  56 . The dust collection part  50  is located beneath the second slot,  152  of the base unit  1  and has an open top  501  which is located in alignment with the second slot  152 . A tube  502  and an outlet  503  are located in communicating with the open top  501  of the dust collection part  50 , preferably, the tube  502  and the outlet  503  are located on two ends of the dust collection part  50 . The hollow hose  51  has a first end connected to the tube  502  and a second end of the hollow hose  51  is connected with an outer cover  52 . 
     The outer cover  52  includes multiple connection tubes  520  and bolts  80  extend through the connection tubes  520  and connects the outer cover  52  to the base unit  1 . The axle  34  extends through an axle hole  525  defined through the outer cover  52 . A shoulder  521  is formed on an inside of the outer cover  52  and an air inlet  522  is defined through the shoulder  521  of the outer cover  52 . The shoulder  521  is located along a periphery of a concaved chamber  524  defined in the inside of the outer cover  52  and includes multiple connection holes  523  for fixing the outer cover  52  to the base  10 . A main-air-outlet  526 , a sub-air-outlet  527  and the axle hole  525  are located in communicating with the concaved chamber  524 . The second end of the hollow hose  51  mentioned above is connected with the sub-air-outlet  527  in the outer cover  52 . An escape pipe  57  has a first end engaged with the main-air-outlet  526 . 
     The fan unit  54  includes a central hole  530  and the axle  34  extends through the central hole  530 . The fan unit  54  is located in the concaved chamber  524  and the separation plate  54  is engaged with the concaved chamber  524 . Multiple blades  531  extend radially from a side of the fan unit  54 . 
     The separation plate  54  includes a path  543 , a guide plate  544 , a first hole  545 , a second hole  546  and a suction opening  547 . The path  543  is located in communication between the air inlet  522  of the outer cover  52 , the first and second holes  545 ,  546  and the suction opening  547 . The guide plate  544  located beside the suction opening  547  and a distal end of the guide plate  544  contacts a peripheral wall of the over cover  52 . The air inlet  522  of the outer cover  52  is located in communication between the outlet  503  of the dust collection part  50  and the path  543  of the separation place  54 . 
     The separation plate  54  includes a rib  542  extending from a side thereof and is shaped corresponding to a shape of the concaved chamber  524 . The rib  542 , the path  543  and the guide plate  544  are located on different planes on the separation plate  54 . A plurality of through holes  541  are defined through the separation plate  54  and bolts  81  extend through the through holes  541  and connect the separation plate  54  to the shoulder  521  of the outer cover  52  such that the rib  542  encloses the concaved chamber  524 . The first hole  545  of the separation plate  4  includes two tapered insides so as to form a gradually divergent hole and the first hole  545  is larger than the second hole  546 , a distal end of the first hole  545  is located at the air inlet  522 . The first hole  545  of the separation plate  4  may also be larger than a cross sectional area at the conjunction between the first hole  545  and the path  543 . The first hole  545  of the separation plate  4  can also be larger than the suction opening  547 . By the arrangements, the distal end of the path  543  is located at the air inlet  522  and the air can enters into the concaved chamber  524  via the second hole  546 , the suction opening  547 , the air inlet  522 , the path  543  and the first hole  545 . 
     The sanding wheel  55  is mounted to the axle  34  and located between the separation plate  54  and the housing  56 . The housing  56  includes multiple apertures  561  and bolts  82  extend through the apertures  561  to connect the housing  56  to the outer cover  52 . A curved restriction plate  562  extends from a side facing the sanding wheel  55  and notches  563  are defined through the curved restriction plate  562 . A pressing plate  564  extends from the inside of the housing  56  so as to define an exterior collection area  9  between the housing  56 , the outer cover  52  and the separation plate  54 . A part of the sanding wheel  55  is located within the exterior collection area  9  and between the separation plate  54  and the housing  56 . The gap between the pressing plate  564  and the sanding wheel  55  is minimized, so as to form a resistance or pressure on the upper area and the air will be guided by the guide plate  544  and enters into the concaved chamber  524 . 
     Before sanding a workpiece (not shown), the motor  31  is activated and the sanding belt  35  is rotated by the operation of the motor  31  via the active pulley  32 , the passive pulley  33  and the axle  34 , the axle  34  drives the lower roller  24 , the fan unit  53  and the sanding wheel  55 . The fan unit  53  is located within the enclosed concaved chamber  524  enclosed by the outer cover  52  and the separation plate  54 , so that the maximum pressure generated by the fan unit  53  enters into the main-air-outlet  526  and the sub-air-outlet  527 , and the air then flows out from the base unit  1  via the escape pipe  57 . The air that does not enter into the main-air-outlet  526  and brought out from the escape pipe  57  enters into the sub-air-outlet  527  and the tube  502  via the hollow hose  51  and the dust collection part  50 . The air flows toward the outlet  503  and enters into air inlet  522  of the outer cover  52 . The air flows into the air inlet  522  flows through the path  543  and the first hole  545 , and is sucked toward center of the fan unit  53  by the suction force generated by the rotation of the blades  531  in the enclosed concaved chamber  524 . The air moves the periphery of the concaved chamber  524  by the eccentric force and enters into the main-air-outlet  526  and is brought out from the base unit  1  via the escape pipe  57 . 
     When sanding the workpiece by the sanding belt  25 , the dust is blew toward the casing  26  and hits the guide member  265  to change the direction of the movement of the dust and then collected in the open top  501  of the dust collection part  50  via the bottom hole  2611  of the casing  26 , the opening  41  of the rear cover  4  and the second slot  152  of the base unit  1 . The dust is sucked by the air flow from the tube  502  toward the outlet  503  and enters into the air inlet  522  of the outer cover  52 . The dust is sucked into the concaved chamber  524  via the first hole  545  by the suction force at the center of the fan unit  2 . The dust is then sent to the periphery of the concaved chamber  524  by the eccentric force of the fan unit  53  and brought out from the base unit  1  via the escape pipe  57  via the main-air-outlet  526 . 
     When sanding the workpiece by the sanding wheel  55 , the dust is blew along the inside of the housing  56  and hits the restriction plate  562  and is guided by the guide plate  544  so that the when the dust flows to the suction opening  547  via the path  543  and the first hole  545 , the suction force by the rotation of the fan unit  53  sucks the dust into the concaved chamber  524  via the first hole  545 . The dust is then sent to the periphery of the concaved chamber  524  by the eccentric force of the fan unit  53  and brought out from the base unit  1  via the escape pipe  57  via the main-air-outlet  526 . 
     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.