Patent Document

FIELD OF THE INVENTION 
       [0001]    The present disclosure generally relates to an apparatus for wood cutting, more specifically, to a table saw with a built-in dust extractor. 
       BACKGROUND OF THE INVENTION 
       [0002]    Table saw is widely used in timber-processing industry for cutting various materials, such as wood, MDF (medium density fiberboard), HDF (high density fiberboard) or other material and composite board. Using a table saw to cut wood material usually produces a large amount of sawdust. At a typical work site, debris is usually scattered over a wide area; fine dust is also released into the air. Not only does it pollute the environment, inhalation of the fine dust may also harm the health of the workers. 
         [0003]    There are some table saws on the market equipped with a built in dust extractor, however, these table saws do not extract dust very well, and still leave lots of dust behind. Some of these table saws do not have the capability of raising, lowering, or tilting the blade, thus render these table saws undesirable. Further, on these existing table saws, the blade is mounted to the snap ring of the rotatable arbor by two locking clamps; there is no reference point for adjusting the blade during installation and/or when the saw is in use. The instability of the blade will produce more sawdust, as a result reduces the effectiveness of the dust extraction. 
         [0004]    Therefore, it is desirable to have a more efficient dust extracting table saw with capability of raising, lowering and tilting the blade, and stability of the blade. 
       SUMMARY OF THE INVENTION 
       [0005]    A new dustless table saw for cutting wood or other material is disclosed herein. 
         [0006]    In accordance with one embodiment, the dustless table saw comprises a blade housing having an arc shaped dust extraction channel, a foldable soft seal connecting the table housing and the blade slot on the table, a dust extraction tube, an extraction turbine, a dust extraction outlet to collect the saw dust, and an anti-dust blade guard. The dust extraction channel inside the blade housing has an opening on its top to allow the blade to extend into the dust extraction channel. 
         [0007]    In accordance with another embodiment, the dustless table saw comprises a U-shaped blade housing with a divider, a dust extraction tube, an extraction turbine, a dust extraction outlet to collect the saw dust, and an anti-dust blade guard. The gap between the blade housing and table should be minimal. 
         [0008]    In accordance with yet another embodiment, the table saw uses one motor to drive the blade and the extraction turbine. In one embodiment, the blade and the turbine are connected using a belt. In another embodiment, the blade and the turbine are connected using a gear box. 
         [0009]    In accordance with yet another embodiment, the table saw uses one motor to drive the blade and another motor to drive the extraction turbine. 
         [0010]    In accordance with yet another embodiment, the table saw uses a pair of bulges and corresponding locking clamps to increase the stability of the blade during operation. 
         [0011]    In accordance with another embodiment, the table saw is equipped with built-in raising/lowering and tilting mechanism to raise/lower and tilt the blade housing and the blade. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The drawings described herein are for illustrating purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. For further understanding of the nature and objects of this disclosure reference should be made to the following description, taken in conjunction with the accompanying drawings in which like parts are given like reference materials, and wherein: 
           [0013]      FIG. 1  is a side view of the table saw with a built-in dust extractor according to one embodiment; 
           [0014]      FIG. 2  is a sketch illustration of the table saw in  FIG. 1 ; 
           [0015]      FIG. 3A  and  FIG. 3B  are cross sectional views of the blade housing of the table saw in  FIG. 1 ; 
           [0016]      FIG. 4  illustrates one embodiment of the foldable seal cover of the table saw in  FIG. 1 ; 
           [0017]      FIG. 5  illustrates another embodiment of a the table saw with a built-in dust extractor; 
           [0018]      FIG. 6  is a sketch illustration of the table saw in  FIG. 5 ; 
           [0019]      FIG. 7  illustrates one embodiment of a blade housing of the table saw in  FIG. 5 ; 
           [0020]      FIG. 8A  and  FIG. 8B  are cross sectional views of the blade housing of the table saw in  FIG. 5 ; 
           [0021]      FIG. 9  illustrates one embodiment of tilting structure; 
           [0022]      FIG. 10  is a sketch illustrating the tilting mechanism in  FIG. 9 ; 
           [0023]      FIG. 11  and  FIG. 12  are side views of the raising/lowering structure according to one embodiment; 
           [0024]      FIG. 13  and  FIG. 14  illustrate one embodiment of a table saw with a single motor to drive both the blade and the dust extraction turbine using a belt; 
           [0025]      FIG. 15  and  FIG. 16  illustrate one embodiment of a table saw with a single motor to drive both the blade and the dust extraction turbine using a gear box; 
           [0026]      FIG. 17  illustrates one embodiment of a table saw with one motor to drive the blade and another motor to drive the extraction turbine; 
           [0027]      FIG. 18  illustrates an exploded view of the blade arbor and the blade according to one embodiment; 
           [0028]      FIG. 19  illustrates one embodiment of the blade with a pair of positioning holes; 
           [0029]      FIG. 20  illustrates one embodiment of anti-dust blade guard; 
           [0030]      FIG. 21  is a cross sectional view of the anti-dust blade guard in  FIG. 20 ; 
           [0031]      FIG. 22  illustrates another embodiment of anti-dust blade guard; 
           [0032]      FIG. 23  is an exploded view of the anti-dust blade guard in  FIG. 22 ; 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0033]    Before explaining the disclosed apparatus and method in detail, it is to be understood that the system and method is not limited to the particular embodiments and that it can be practiced or carried out in various ways. 
         [0034]    Referring now to  FIG. 1  and  FIG. 2 , a table saw comprises a table  20  and a saw compartment base under the table. The table saw includes a blade slot  2  on the table surface. A circular blade  4  of the saw compartment extends up through the blade slot  2  to the table surface. The saw compartment includes a blade housing  8 , a dust extraction tube  10 , a dust exhaust tube  14 , and an extraction turbine  12 . In one embodiment, a foldable soft seal  6  connects the blade housing  8  and the blade slot  2 . A piece of wood, or other material to be cut, is placed on the table  20  and pushed to the blade  4  to make the cut. With the extracting turbine  12  running, the saw dust is extracted into the blade slot  2 , through the foldable seal  6 , into the blade housing  8 , then to dust extraction tube  10 , into the turbine chamber, and finally is blew into the dust exhaust tube  14  and out at the dust outlet  16 . The dust is collected at the outlet  16  using a dust collection bag. Changing and cleaning the dust collection bag frequently helps increase the efficiency of the dust extraction. 
         [0035]    The foldable seal  6  is made of airtight material. In accordance with one embodiment, the foldable seal  6  is shaped like an organ cover, as shown in  FIG. 4 . The foldable seal  6  includes a PVC frame  6   a,  and a waterproof, sunproof PVC coated fabric  6   b.    FIG. 4  also illustrates the foldable seal  6  in both stretched and compressed states. The foldable seal  6  may also be in other shapes, such as canvas like structure. 
         [0036]    Referring back to  FIG. 2 , the foldable seal  6  seals the connection between the blade housing  8  and table  20  as shown in  FIG. 2 , making the blade slot  2  as the first air intake for the dust extraction apparatus of the saw compartment. The saw dust scatters around the blade slot  2  when the wood is cut. With the operating of the dust extraction apparatus, a pressure difference between the blade housing  8  and the blade slot  2  is maximized, hence optimally extracts the sawdust into the dust extraction apparatus. During the operating of the table saw, the wood or other material is pushed into the blade  4  on the table  20 , thus gradually blocks the first air intake (the blade slot  2 ). In accordance with one embodiment, a second air intake  9  is provided in the blade housing  8  with appropriate size and shape, as shown in  FIG. 2 . When the first air intake (the blade slot  2 ) is blocked, the pressure difference at the second air intake  9  increases, adjusting the air intake to make sure the apparatus is working optimally. 
         [0037]    Referring now to  FIGS. 3A and 3B , an arc shaped dust extraction channel  8   a  is illustrated from two different positions. The dust extraction channel  8   a  is a part of the blade housing  8 . In accordance with one embodiment, the dust extraction channel  8   a  is a curved channel-with an opening at the top for the blade  4 . The dust extraction channel  8   a  covers part of the blade teeth. The dust extraction channel  8   a  has a gap at the top for the blade  4 . The width of the gap is a little bit larger than the width of the blade  4 . The end of the dust extraction channel  8   a  connects to the dust extraction tube  10  which connects to the extraction turbine  12 . When the blade is in operating condition, the sawdust is produced at the saw teeth edge. With the extraction turbine  12  running, the disclosed structure allows the sawdust go through the dust extraction channel  8   a  and the dust extraction tube  10  into the dust exhaust tube  14  and collected at the outlet  16 . The disclosed structure maximizes the dust extraction. In a test conducted using the disclosed structure, the dust extraction rate is 98%. The disclosed structure also optimizes the overall structure of the apparatus and cuts the cost. 
         [0038]    Referring now to  FIG. 5  and  FIG. 6 , another embodiment of the table saw is illustrated. Similar to the table saw illustrated in  FIGS. 1 and 2 , this embodiment also comprises a blade slot  2  on the table surface, a circular blade  4  extends up through the blade slot  2  to the table surface, a blade housing  8  under the table  20  to enclose the blade  4 , a dust extraction tube  10 , a dust exhaust tube  14 , and an extraction turbine  12 . With the extracting turbine  12  running, the saw dust is extracted into the blade slot  2 , into the blade housing  8 , then to dust extraction tube  10 , into the turbine chamber, and finally is blew into the dust exhaust tube  14  and out at the dust outlet  16 . The dust is collected at the outlet  16  using a dust collection bag. This embodiment of the table saw does not use the soft foldable seal. The blade housing  8  is fixed vertically. The gap between the bottom of the table  20  and the top of the blade housing  8  should be minimal to ensure minimum escape of the saw dust from this gap. When the first air intake (the blade slot  2 ) is blocked, the gap becomes the second air intake for the blade housing. 
         [0039]    As illustrated in  FIG. 7 , the blade housing  8  comprises a front cover  7  and a back cover  3 . The front cover  7  and the back cover  3  are fixed together using a set of screws. In one embodiment, the front cover  7  and the back cover  3  are U-shaped structures. A horizontal bar  5  is latched onto the two arms of the front cover  7  with appropriate latching mechanism to provide additional stability of the blade housing. The horizontal bar  5  may be removed by hand for installation and changing of the blade  4 . As long as the blade  4  does not come in contact with the blade housing  8 , the gap between the blade housing  8  and the blade body should be minimal. 
         [0040]      FIGS. 8A and 8B  illustrate the blade housing  8  with the blade  4  in different positions. As shown in  FIGS. 8A and 8B , the saw teeth under the table  20  are always enclosed in the blade housing  8 . Inside the blade housing  8 , a divider  3   a  is located between the upper arm of the blade housing  8  and the dust extraction tube  10 . The divider  3   a  divides the blade housing  8  into two separate spaces at the junction of the blade housing and the dust extraction tube  10  to divert the air flow generated by the extracting turbine  12 . As a result, the junction from the blade housing  8  to the dust extraction tube  10  is divided to two areas. The ration of these two areas is set to a value that maximizes the extraction. 
         [0041]    Some of existing table saws on the market have some capability of tilting the blade but lack of functionality of raising, lowering the blade; others use a single handwheel to raise, lower, and tilt the blade, the resulting blade position may not be that accurate. The instant paper discloses a mechanism using two handwheels for adjusting the blade position: a front handwheel for raising/lowering the blade, and a side handwheel for tilting the blade. 
         [0042]      FIGS. 9-10  illustrate a mechanism for tilting the blade  4  in accordance with one embodiment. The tilting mechanism includes a vertical plate  22 , a tilting axis  24 , a tilting plate  26 , a tilting screw rod base  28 , a tilting screw rod  30 , and a tilting handwheel  38 . The vertical plate  22  is vertically mounted to the bottom of the table  20  through positioning holes. The vertical plate  22  has a semicircle shaped opening. The tilting plate  26  is pivoted on the vertical plate  22  through the tilting axis  24  in the semicircle shaped opening. The tilting screw rod base  28  is attached to the tilting plate  26 . The handwheel  38  is connected to a base  34  mounted to the table saw frame through a connecting rod  36 . The tilting screw rod  30  pivots to the tilting screw rod base  28 , and connects to the tilting handwheel  38  via the connecting rod  36  via a gimbal joint  32 . Turn the tilting handwheel  38 , the connecting rod  36  starts to tilt, then the gimbal joint  32  tilts, and the tilting screw rod  30  tilts, the tiling screw rod base  28  turns slightly, as a result the tilting plate  26  tilts around the center of the semicircle opening on the vertical plate  22 , therefore tilts the blade  4 . 
         [0043]      FIGS. 11-12  illustrate a mechanism for raising and lowering the blade in accordance with one embodiment. The raising/lowering mechanism includes a positioning slider  42 , a lifting screw rod  46 , a lifting rod  52 , and a lifting handwheel  54 . The positioning slider  42  connects to the motor base  44  at one side, and mounts to the blade housing  8  at the other side. The motor base  44  may slide freely along the sliding rail (not shown) on the tilting plate  26 . The motor base  44  has a set of holes with threads suitable for connecting with the lifting screw rod  46 . One end of the lifting screw rod  46  connects with a driven gear  48 , and bends into the flange hole on the tilting plate  26 . A driving gear  50  is coupled with the driven gear  48 . The driving gear  50  connects with the lifting rod  52 , and the lifting rod  52  connects to the lifting handwheel  54 . Turn the lifting hand wheel  54 , the lifting rod  52  tilts, causing the driving gear  50  and the coupled driven gear  48  in motion, and in turn causing the lifting screw rod  46  to tilt, the motor base  44  slides along the sliding rail on the tilting plate  26 , and the blade housing  8  slides along with the motor base  44 . 
         [0044]      FIGS. 13-16  illustrate embodiments using a single motor for both blade and the dust extraction. 
         [0045]    Referring now to  FIGS. 13-14 , as shown, a motor  62 , the blade arbor  70 , and the extraction turbine  12  are all mounted to the motor base  44 . The motor  62  has a motor pulley  64 . The motor pulley  64  connects with a blade pulley  68  on the blade arbor  70  via a blade belt  66 . The blade arbor  70  is mounted to the motor base  44  via bearings. One end of the blade arbor  70  connects to the blade  4 . The other end of the blade arbor  70  connects to an extraction driving wheel  72 , which connects to the extraction turbine  12  through an extraction belt  74 . In another embodiment, the motor directly drives the blade  4 , the motor also connects to the extraction turbine  12  through a belt. 
         [0046]      FIGS. 15-16  illustrate one embodiment using a gear box  76  to connect the blade  4  and the extraction turbine  12 . The motor  62  connects a driving shaft  84 , which mounts to the gear box  76  via bearing  78 . The middle section of the driving shaft  84  connects with a small helical gear  82 . One end of the blade arbor  70  is mounted to the gear box  76  via bearings  78 . The middle section of the blade arbor  70  connects to a large helical gear  80 . The small helical gear  82  and the large helical gear  80  are coupled to form a set of helical gears. The other end of the driving shaft  84  connects to the extraction turbine  12 . The other end of the blade arbor  70  connects to the blade  4 . 
         [0047]      FIG. 17  illustrates an embodiment using the motor  62  to drive the blade  4 , and an extraction motor  60  to drive the extraction turbine  12 . As shown, the motor  62  mounted on the motor base  44  has a motor pulley  64 . The motor pulley  64  connects with the blade pulley  68  on the blade arbor  70  via the blade belt  66 . The blade arbor  70  is mounted to the motor base  44  via bearings. One end of the blade arbor  70  connects to the blade  4 . The extraction motor  60  is also mounted on the motor base  44 . The extraction motor  60  connects to the extraction turbine  12  to drive the extraction turbine  12 . 
         [0048]    Referring now to  FIGS. 18-19 , the blade  4  has a pair of positioning holes  4   b  in accordance with one embodiment. The vibration of the blade along its axis direction increases the width of the kerf, as a result increases the saw dust. In one embodiment, a pair of bulges and corresponding locking clamps are used to increase the stability of the blade during operation. As shown in  FIGS. 18-19 , the blade  4  has a pair of positioning holes  4   b.  During the installation of the blade  4 , inset the bulges  86  into the positioning holes  4   b,  clamp the corresponding locking clamps  90  onto the bulges  86 , then use a locking screw  92  to tighten the blade  4 . The bulges  86  and the matching locking clamps  90  may be in various shapes. The positioning holes may also in various shapes. 
         [0049]    Referring now to  FIG. 20  and  FIG. 21 , one embodiment of an anti-dust blade guard is illustrated. An anti-dust blade guard  102  connects to the table  20  through a connector  104  and a splitter  106 . The anti-dust guard  102  comprises an air intake  102   a,  a first barrier  102   b,  a second barrier  102   c,  and a third barrier  102   d.  The anti-dust blade guard  102  may automatically adjust its height according to the depth of the wood  108  and make the bottom of the blade guard fit the wood exactly to create a sealed room. The blade guard air intake  102   a  is located at the top front of the blade guard  102 . When the blade  4  cuts the wood board  108 , the anti-dust blade guard  102  can prevent the saw dust from scattering into the working environment. During the wood cutting operation, the saw debris and dusts are produced and scattered into the direction of the spinning. The first barrier  102   b  can cut off some of the saw debris and saw dusts. These saw debris and saw dusts may be cut by the blade for the second time and continue scattering into the direction of the spinning. The second barrier  102   c  may cut off some of these saw debris and saw dusts. The third barrier  102   d  diverts the air flow and cut off the remaining saw dusts. The air flow diverted by the third barrier  102   d  and the air flow generated by the spinning blade  4  work together to make the saw dusts remain in the blade guard  102  and let the saw dust go into the blade housing  8  through the kerf of the wood board. 
         [0050]    Referring to  FIG. 22  and  FIG. 23 , another embodiment of an anti-dust blade guard is illustrated. As shown, the anti-dust blade guard comprises a pair of blade guard side barriers  103 , a blade guard strut  107 , and a hollow blade guard cover  105 . One end of the blade guard strut  107  is fixed to a splitter  106 . A pair of screw holes is located at each end of the blade guard strut  107 . There is a circular hole at each side of the blade guard cover  105  back end, and a groove at each side of the front end of the blade guard cover  105 . Each side barrier  103  has a pair of oval grooves, one at each end. During installation, a screw goes through the back end groove of the side barrier  103 , the circular hole at the back end of the hollow blade guard cover  105 , and one of the screw holes at the back end of the blade guard strut  107 . At the front end, a screw goes through the front end groove of the side barrier  103 , the circular hole at the front end of the hollow blade guard cover  105 , and one of the screw holes at the front end of the blade guard strut  107 . This structure allows side barriers  103  to move freely. The blade guard may self-adjust according to the lifting and/or tilting of the blade in order to make the cutting area in a relatively sealed room and prevent the saw dust from scattering into the working environment. 
         [0051]    Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications can be made to these embodiments without changing or departing from their scope, intent or functionality. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the invention is defined and limited only by the claims that follow.

Technology Category: b