Abstract:
A table saw includes a base, a work table having a cutting opening, a tank for receiving cooling liquid, a blade partly extending out from the cutting opening, and a guard assembly. The guard assembly includes a guard for covering the blade and for moving upwards under the action of a workpiece. In a working condition, at least a portion of the guard abuts against the workpiece, and the workpiece can slide relative to the guard. The guard has a guiding wall which abuts against the workpiece in the working condition and which guides the cooling liquid into a kerf in the workpiece formed by the blade. Because the table saw collects the cooling liquid brought by the blade and returns it to the tank for receiving the cooling liquid through the cutting opening of the work table, the table saw effectively controls the cooling liquid splashed during the cutting operation of the workpiece and prevents the cooling liquid from splashing to dirty the operator, the work table, and the workpiece, saves the time of cleaning the workpiece after cutting, and enhances the operating comfort of the operator.

Description:
RELATED APPLICATION INFORMATION 
       [0001]    This application claims the benefit of CN 201410027558.9, filed on Jan. 20, 2014, and CN 201310044042.0, filed on Feb. 2, 2013, the disclosures of which are incorporated herein by reference in their entirety. 
       FIELD OF THE DISCLOSURE 
       [0002]    The following generally relates to table saws and, more particularly, to a cooling liquid guiding system for a table saw. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    A table saw can be used for cutting materials such as porcelain tile, ceramic tile, and so on. As shown in  FIG. 1 , a conventional table saw mainly comprises a base  11 , a work table  12  supported on the base  11 , a tank  13  arranged below the work table  12  for accommodating a cooling liquid, a blade  14  driven by a motor, and a guard assembly  15  mounted on the base  11 . 
         [0004]    During the cutting operation, the blade  14  is driven by the motor to perform a high-speed rotating motion, and a workpiece is positioned on the work table  12 . Then the workpiece is pushed toward the blade  14  gradually by the operator to perform the cutting operation. When the blade  14  rotates at high speed, the cooling liquid in the tank  13  will be brought to a cutting area on the work table  12  by the blade  14 . Thus, there is a lot of cooling liquid splashing around the cutting edge of the blade  14 . In the prior art, the guard assembly  15  is used to block the splashing cooling liquid. However, the guard assembly  15  can only cover a part of the blade  14 , and there is still another part of the blade  14  exposed. Therefore, the guard assembly  15  can only block a part of the cooling liquid brought by the blade, and most of the cooling liquid will splash to the operator and flow to the work table and the workpiece, as shown by arrows in  FIG. 1 . As a result, the clothes of the operator would be stained by the cooling liquid brought by the blade. Further, the cooling liquid blocked by the guard assembly falls on the work table or the workpiece, and stains the work table and the workpiece. 
       SUMMARY 
       [0005]    The following describes a table saw that overcomes the deficiencies existing in the prior art and which can effectively prevent the cooling liquid from splashing during the cutting operation. 
         [0006]    An exemplary table saw that meets these objectives comprises a base; a work table, for placing a workpiece, supported on the base, the work table having a cutting opening; a tank for accommodating the cooling liquid arranged below the work table; a blade driven by a motor which partially extends out from the cutting opening; and a guard assembly mounted on or adjacent to the work table, the guard assembly comprising a guard element for covering at least a portion of the blade, wherein the guard element comprises an inside wall extending from a center area above the blade to both sides of the guard element outwardly and downwardly; a cooling liquid guiding channel extending along a lower portion of the guard element and descending towards the backend of the guard element; and a discharging opening communicating with the cooling liquid guiding channel, the discharging opening allowing the cooling liquid to flow away from the guard element and go back into the tank through the cutting opening. 
         [0007]    In the working condition, at least a portion of the guard of the table saw abuts against the workpiece, and a hollow chamber is formed between the guard and the workpiece. As a result, the cooling liquid brought to the work table when the blade rotates at high speed is controlled into the hollow chamber, and then the cooling liquid cannot splash to the outside of the guard, which effectively controls the splashing of the cooling liquid. Due to the inside wall, the cooling liquid that falls towards the workpiece is guided to the kerf in the workpiece formed by the blade, thus the cooling liquid can get away from the surface of the workpiece via the kerf in the workpiece, which ensures there is no redundant cooling liquid left on the surface of the workpiece. 
         [0008]    Preferably, the kerf of the workpiece and the cutting opening of the work table are almost in one line, so the cooling liquid can flow back to the tank for receiving the cooling liquid through the kerf of the workpiece and the cutting opening of the work table. Thus, the described table saw has the function of collecting the cooling liquid brought by the blade and then guiding and returning it to the tank for receiving the cooling liquid through the cutting opening of the work table, which effectively controls the cooling liquid that is splashed during the cutting operation of the workpiece, prevents the cooling liquid from splashing to dirty the operator, the surroundings and the workpiece, saves the time of cleaning the workpiece after the cutting operation, and enhances the operating comfort of the operator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic view of a table saw of the prior art; 
           [0010]      FIG. 2  is a schematic view of an exemplary table saw constructed according to the description which follows in a non-working condition; 
           [0011]      FIG. 3  is a schematic view of the table saw in a working condition; 
           [0012]      FIG. 4  is a schematic view of an exemplary guard assembly of the table saw; 
           [0013]      FIG. 5  is a schematic view showing the inner structure of the guard assembly of  FIG. 4 ; 
           [0014]      FIG. 6  is a cross-sectional view of the guard assembly of  FIG. 4 ; 
           [0015]      FIG. 7  is a sectional view of the table saw in a working condition; 
           [0016]      FIG. 8  is a partial enlarged view showing the inner structure of the guard assembly of  FIG. 4 ; 
           [0017]      FIG. 9  is a schematic view showing an exemplary flexible ring of the guard assembly of  FIG. 4  guiding the liquid; 
           [0018]      FIG. 10  is a schematic view of a further exemplary guard assembly; 
           [0019]      FIG. 11  is a schematic view of a still further exemplary guard assembly; 
           [0020]      FIG. 12  is a front view of the guard assembly of  FIG. 11 ; 
           [0021]      FIG. 13  is a bottom view of the guard assembly of  FIG. 11 ; 
           [0022]      FIG. 14  is a partial enlarged view of the portion E 1  of  FIG. 12 ; and 
           [0023]      FIG. 15  is a partial enlarged view of the portion E 2  of  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    As shown in  FIGS. 2-3 , a table saw of the present invention comprises a base  21 , a work table  22 , for carrying a workpiece  20 , supported on the base  21 , a tank  23  (as shown in  FIG. 7 ) arranged below the work table  22  for accommodating the cooling liquid, a blade  24  driven by a motor and a guard assembly  25 . The guard assembly  25  is capable of being mounted directly on the work table  22  or a component adjacent to the work table  22  and comprises a guard element  254  for covering at least a portion of the blade  24 . The work table  22  has a cutting opening  220  (as shown in  FIG. 6 ) from which the blade  24  partially extends out. In a non-working condition, as shown in  FIG. 2 , the extended portion of the blade  24  is covered by the guard element  254 . 
         [0025]    The table saw further comprises a cooling liquid guiding system. The cooling liquid brought out of the tank  23  by the blade  24  rotating at high speed can be restrained within the guard element  254  by the cooling liquid guiding system, and then flow out of the guard element  254  for return back to the tank  23  through the cutting opening  220 . Thereby the cooling liquid is collected and back flowed. The cooling liquid guiding system comprises the guard assembly  25  for restraining the cooling liquid brought by the blade  24 , the work table  22  having the cutting opening  220  and the tank  23  for accommodating the cooling liquid. 
         [0026]    The following will describe the structure of the guard assembly  25  being capable of controlling and guiding the cooling liquid brought by the blade. 
         [0027]    It should be noted that “frontend” in this description means the end adjacent to the operator during the operation, and “backend” means the end away from the operator. 
         [0028]    As shown in  FIG. 4 , the guard assembly  25  comprises a riving knife  251 , a link mechanism  252 , a locking knob  253  and the guard element  254 . A flexible ring  255  is mounted to the bottom of the guard element  254 . The guard assembly  25  is mounted on the work table  22  or a component near the work table  22  by the riving knife  251 . Specifically, the riving knife  251  is formed with mounting holes  2511  at its lower end, and bolts will pass through the mounting holes  2511  and engage with threaded holes on the working table  22  or the component near the working table  22 , whereby the riving knife  251  and the whole guard assembly  25  are fixed to the working table  22  or the component near the working table  22 . 
         [0029]    The guard element  254  is connected with the riving knife  251  by the link mechanism  252 , and can move upwards and downwards relative to the riving knife  251 . The link mechanism  252  comprises a first connecting rod  2521 , a second connecting rod  2522 , and a spring  2523  connected between the first and second connecting rod  2521 ,  2522 . A first mounting plate  2541  and a second mounting plate  2542  extend from the guard element  254 , which are parallel to each other. A gap is formed between the first and second mounting plate  2541 ,  2542 . A first end of each of the first and second connecting rod  2521 ,  2522  is connected to the upper end of the riving knife  251  respectively by a bolt  2524 , and a second end of each of the first and second connecting rod  2521 ,  2522  is inserted into the gap and respectively connected to the first and the second connecting rod  2521 ,  2522  by a bolt  2525 . The spring  2523  provides an acting force so that the guard element  254  will tightly abut against the work table  22  or the workpiece  20 . In the non-working condition, as shown in  FIG. 2 , the guard element  254  tightly abuts against the work table  22 , and due to the flexible ring  255 , an enclosed chamber is formed between the guard element  254  and the working table  22 . In the working condition, as shown in  FIG. 7 , at least a portion of the guard element  254  tightly abuts against the workpiece  20 , and the workpiece  20  can move relative to the guard element  254 . In other embodiments, the spring  2523  may be replaced by other elastic elements such as torsion spring or even be omitted. If the spring is omitted, the guard element  254  abuts against the work table  22  or the workpiece  20  under the action of gravity. 
         [0030]    The locking knob  253  is connected to one of the bolts  2524  for fixing the guard element  254  at a certain position relative to the riving knife  251 . In this embodiment, the locking knob  253  is connected to the bolt  2524  at the first end of the first connecting rod  2521 . When the locking knob  253  is locked, the first connecting rod  2521  is fixed, and the guard element  254  is fixed at a certain height. When the locking knob  253  is released, the guard element  254  is operable of being moved upwards and downwards. In other embodiments, the locking knob  253  may also be connected to the bolt  2524  at the first end of the second connecting rod  2522 . 
         [0031]    As shown in  FIG. 4 , the guard element  254  is formed with a window  2540  at its front end, through which the operator can easily observe a cutting point. The cutting point herein refers to the contact point between the cutting edge of the blade and the workpiece. The window  2540  comprises a division plate  2570  dividing the window  2540  into two parts. The division plate  2570  is located above the cutting point and has a width greater than the thickness of the blade  24  so as to block debris from traveling towards the eyes of the operator. It should be noted that the shape and the number of the window may be changed according to the requirements as long as the cutting points can be observed easily. 
         [0032]    The guard element  254  further comprises a guiding part  2543  at its front end. The guiding part  2543  extends toward the front of the guard element  254  obliquely and upwardly. In this embodiment, the guiding part  2543  includes two guiding ribs. As shown in  FIG. 3 , during the cutting operation, the workpiece  20  is placed on the work table  22 , and then pushed toward the blade  24  by the operator. The workpiece  20  first contacts the guiding rib  2543  and then overcomes the acting force of the spring  2523  so that the guard element  254  is lifted and moved upwards, and finally the guard element  254  falls on the workpiece  20  and tightly abuts against the workpiece  20  under the action of the spring  2523 . As shown in  FIG. 7 , if the workpiece  20  has not reached the backend of the guard element  254 , a part of the bottom surface of the guard element  254  tightly abuts against the workpiece  20 . As shown in  FIG. 8 , when the workpiece  20  reaches the backend of the guard element  254 , the whole bottom surface of the guard element  254  tightly abuts against the workpiece  20 . 
         [0033]    As shown in  FIG. 9 , the flexible ring  255  comprises a guiding wall  2553  at its backend for guiding the flowing direction of the cooling liquid. The guiding wall  2553  has a front part and a rear part which is closer to the blade than the front part. Preferably, the guiding wall  2553  is a V-shaped inclined plane. Under the action of the spring  2523 , the guiding wall  2553  abuts against the workpiece  20 . Preferably, the flexible ring  255  is a rubber ring; in other embodiments, the flexible ring  255  may also be formed by other flexible materials such as felt, brush bristles, and so on. 
         [0034]    As shown in  FIG. 5 , the guard element  254  is generally configured as arc-shaped. As shown in  FIG. 6 , the guard element  254  has an arc-shaped section and an arc-shaped inside wall extending from a center area of the guard element  254  above the blade  24  towards two sides of the guard element  254  outwardly and downwardly. The guard element  254  comprises a first side wall  2544  and a second side wall  2545  opposite to each other. Thus, the guard element  254  is constituted to form a chamber therein. In  FIG. 5 , the first side wall  2544  is removed, thus the inner structure of the guard element  254  is clearly shown. A first guiding plate  2546  and a second guiding plate  2547  are respectively mounted on the lower part of the inner wall of the first side wall  2544  and the second side wall  2545 , and each of the first guiding plate  2546  and the second guiding plate  2547  extends towards the backend of the guard element  254  obliquely and downwardly along the first side wall  2544  and the second side wall  2545 , that is to say, the frontend of each of the first and second guiding plate  2546 ,  2547  is higher than the backend thereof, and the angle β between each of the first and second guiding plate  2546 ,  2547  and the horizontal plane is more than 1°. A space is formed between the first guiding plate  2546  and the second guiding plate  2547 , through which the blade  24  can pass. In the sectional view as shown in  FIG. 6 , the first guiding plate  2546  and the second guiding plate  2547  forms a “splayed” shape. The configuration of the first guiding plate  2546  and the second guiding plate  2547  forms a first guiding channel  2548  and a second guiding channel  2549 . Each of the first and second guiding channel  2548 ,  2549  comprises a first side adjacent to the blade  24  and a second side away from the blade  24  and coupled to the inside wall of the guard element  254 , and the first side is higher than the second side in the vertical direction. 
         [0035]    At the backend of the guard element  254 , a discharging opening  2560  is formed between the first guiding plate  2546  and the second guiding plate  2547 . The discharging opening  2560  substantially aligns with the blade  24  in the feeding direction, and communicates with the cutting opening  220 . When the workpiece  20  is moved to the backend of the guard element  254  below the discharging opening  2560 , the discharging opening  2560  communicates with a kerf  200  of the workpiece cut by the blade  24  and the cutting opening  220 . Preferably, in the perpendicular direction, that is, in the direction perpendicular to the work table  22 , the discharging opening  2560  substantially aligns with the cutting opening  220 , and when the workpiece  20  moves to the back of the blade  24  below the discharging opening  2560 , the discharging opening  2560  substantially aligns with the kerf  200  of the workpiece and the cutting opening  220 . It should be noted by the person skilled in the art that the discharging opening  2560  may partly align with the kerf  200  of the workpiece and the cutting opening  220  or communicate with each other by additional guiding mechanisms. 
         [0036]    A blocking plate  2550  is arranged in front of the discharging opening  2560 . Since the first guiding channel  2548  and the second guiding channel  2549  become narrower gradually toward the back end thereof, the blocking plate  2550  can prevent the cooling liquid in the first and second guiding channel  2548 ,  2549  from flowing back to the workpiece  20 . 
         [0037]    A first baffle  2551  and a second baffle  2552  which are configured as reversed U-shaped are arranged within the guard element  254  for blocking the cooling liquid brought by the blade  24  into the guard element  254  and guiding the cooling liquid splashing to the first baffle  2551  and the second baffle  2552  into the first guiding channel  2548  and the second guiding channel  2549 . The first baffle  2551  and the second baffle  2552  are respectively connected between the top in the guard element  254  and the first guiding plate  2546  and the second guiding plate  2547 , and separated from the inner surfaces of the first side wall  2544  and the second side wall  2545  of the guard element  254 . In other embodiments, the first baffle  2551  and the second baffle  2552  may only be connected to the inner surfaces of the first side wall  2544  and the second side wall  2545  of the guard element  254 , or only connected to the first guiding plate  2546  and the second guiding plate  2547 . 
         [0038]    As shown in  FIG. 7 , the tank  23  for receiving the cooling liquid is filled with the cooling liquid. A portion of the blade  24  is immerged into the cooling liquid. A third baffle  231  is arranged at the back of the blade  24 , and the lower end of the third baffle  231  is also immerged into the cooling liquid, and the upper end is laterally provided with a flexible body  232  extending towards the blade  24 . A slot is cut in the flexible body  232  through which the blade  24  passes and directly contacts the flexible body  232 . Preferably, the flexible body  232  is felt, and in other embodiments, the flexible body  232  may also be formed by other flexible materials. 
         [0039]    The following will describe the working process of the cooling liquid guiding system. 
         [0040]    In the working condition, the blade  24  is driven by the motor to rotate at high speed, and plenty of the cooling liquid may rotate with the blade  24 . As shown by dashed arrows in  FIG. 7 , the dashed arrows indicate the splashing direction of the cooling liquid brought by the blade  24  from the tank  23  for receiving the cooling liquid. One part of the cooling liquid may be blocked by the flexible body  232  so as to fall into the tank  23  for receiving the cooling liquid, and the other part of the cooling liquid may splash through the gap between the flexible body  232  and the blade  24  and may be brought to the work table  22  by the blade  24  so as to cool the blade  24 . Since the flexible body  232  directly contacts the cutting edge of the blade  24 , the cooling liquid may be distributed on the cutting edge of the blade  24 , thereby reducing the amount of the cooling liquid brought to the work table  22 . 
         [0041]    As shown by the dashed arrows in  FIGS. 5-7 , the cooling liquid brought to the work table  22  may enter into the guard element  254  along the tangential direction of the blade  24  and then splash to the inner surface of the guard element  254  and the first and second baffles  2551 ,  2552 . As shown by the solid arrows in  FIGS. 5-7 , the solid arrows indicate the flowing direction of the blocked and collected cooling liquid. The cooling liquid splashed to the inside wall of the guard element  254  may flow into the first guiding channel  2548  and the second guiding channel  2549  along the inside wall, i.e., the inner surfaces of the first side wall  2544  and the second side wall  2545 . Meanwhile, the cooling liquid splashed to the first baffle  2551  and the second baffle  2552  may be blocked by the first baffle  2551  and the second baffle  2552  and flow into the first guiding channel  2548  and the second guiding channel  2549  along the first baffle  2551  and the second baffle  2552 . The cooling liquid collected in the first guiding channel  2548  and the second guiding channel  2549  may flow towards the tail end of the guard element  254  along the inclining direction of the first guiding channel  2548  and the second guiding channel  2549  and converge to the discharging opening  2560 . Due to the blocking plate  2550  arranged at the discharging opening  2560 , the cooling liquid at the discharging opening  2560  cannot flow back into the guard element  254 . As shown in  FIG. 7 , if the workpiece  20  has not reached the back end of the guard element  254  below the discharging opening  2560 , the discharging opening  2560  is substantially in line with the cutting opening  220  of the work table, thus the cooling liquid collected in the first guiding channel  2548  and the second guiding channel  2549  can be discharged from the discharging opening  2560 , and fall into the tank  23  for receiving the cooling liquid through the cutting opening  220  of the work table. As shown in  FIG. 8 , when the workpiece  20  moves to the back end of the guard element  254  below the discharging opening  2560 , the discharging opening  2560  is substantially in line with the kerf  200  of the workpiece and the cutting opening  220 . Thus, the cooling liquid collected in the first guiding channel  2548  and the second guiding channel  2549  can be discharged from the discharging opening  2560  through the kerf  200  of the workpiece and the cutting opening  220  of the work table, and finally flow into the tank  23  for receiving the cooling liquid. 
         [0042]    Although most of the cooling liquid brought into the guard element  254  by the blade  24  may be collected in the first guiding channel  2548  and the second guiding channel  2549 , some cooling liquid cannot be collected in the first guiding channel  2548  and the second guiding channel  2549 , but rather falls on the workpiece  20 . As shown in  FIG. 9 , the cooling liquid which is not collected in the first guiding channel  2548  and the second guiding channel  2549  can be enclosed into the workpiece area covered by the guard element  254  via the flexible ring  255 . As shown in the solid arrow in the figures, during the cutting operation, as the workpiece  20  is pushed towards the back end of the guard element  254 , the cooling liquid in the workpiece area covered by the guard element  254  will be moved to the back end of the guard element  254  along with the workpiece  20 , and this part of cooling liquid may be guided to the kerf  200  of the workpiece by the guiding wall  2553  of the flexible ring, and finally flow into the tank  23  for receiving the cooling liquid through the kerf  200  of the workpiece and the cutting opening  220  of the work table. 
         [0043]    With the above cooling liquid guiding system, the cooling liquid brought by the blade  24  can be effectively controlled in the guard element  254  and then effectively collected and guided back to the tank  23  for receiving the cooling liquid, which can effectively avoid the cooling liquid from splashing to dirty the operator, the surroundings, and the workpiece while enhancing the comfort of the operator upon cutting the workpiece. 
         [0044]    In other embodiments, the first guiding channel  2548  and the second guiding channel  2549  may be arranged outside of the guard element  254  and extend to the back end of the guard along the outer wall of the guard element  254  to form the discharging opening  2560 . The cooling liquid collected in the first guiding channel  2548  and the second guiding channel  2549  may flow from the discharging opening  2560  to the tank  23  through the cutting opening  220  of the work table. 
         [0045]      FIG. 10  shows a second embodiment. This embodiment differs from the above described embodiment in that the riving knife  251 ′ of the guard assembly  25 ′ is formed with at least one guiding element  2512 ′ for guiding the cooling liquid to the cutting opening. In the present embodiment, the guiding element is a guiding slot. Person skilled in the art may consider that the guiding element may be guiding rib or other structure that can guide the flowing direction of the cooling liquid. Preferably, the guiding slots  2512 ′ are arc-shaped. Specifically, the shape of the guiding slots  2512 ′ is the same as the moving track of the discharging opening, thus the discharging opening is communicated with the guiding slots  2512 ′ during the whole cutting process. Therefore, when the guard element  254 ′ is at different heights, the cooling liquid collected in the first and second guiding channels can flow to the guiding elements  2512 ′ through the discharging opening, and then finally flow into the tank for receiving the cooling liquid through the kerf of the workpiece and the cutting opening of the work table. This embodiment can guide the cooling liquid collected in the guiding channels back to the tank more effectively. 
         [0046]      FIGS. 11-15  show a third embodiment. As shown in  FIGS. 11-12 , in this embodiment, the back end of the guard element  254 ″ is formed with an engaging slot  258 ″ for engaging with the riving knife  251 ″, and the riving knife  251 ″ extends through the engaging slot  258 ″. In the direction perpendicular to the plane of the blade, the width of the elongated slot  258 ″ is slightly larger than the thickness of the riving knife  251 ″. Preferably, in the direction parallel to the plane of the blade, the length of the elongated slot  258 ″ is larger than the length of the riving knife  251 ″. This design ensures that the guard element  254 ″ cannot easily shake in the direction perpendicular to the plane of the blade and can move relative to the riving knife  251 ″ in the direction parallel to the plane of the blade, thus the guard of this embodiment has good stability. 
         [0047]    The guard element  254 ″ is connected to the riving knife  251 ″ by the link mechanism  252 ″. The link mechanism  252 ″ comprises a first connecting rod  2521 ″, a second connecting rod  2522 ″ and a third connecting rod  2526 ″. One end of the first connecting rod  2521 ″ is mounted to the riving knife  251 ″ in a cantilever form by the locking knob  253 ″, and located above the guard element  254 ″. The first end of each of the second connecting rod  2522 ″ and the third connecting rod  2526 ″ is pivotally connected to the first connecting rod  2521 ″, and the second end opposite to the first end is pivotally connected to the side wall of the guard element  254 ″. The first end of the second connecting rod  2522 ″ is pivotally connected to the front end of the first connecting rod  2521 ″, and the first end of the third connecting rod  2526 ″ is pivotally connected to the middle part of the first connecting rod  2521 ″. Preferably, there are two second connecting rods  2522 ″ and two third connecting rods  2526 ″. The two second connecting rods  2522 ″ and the two third connecting rods  2526 ″ are respectively arranged on the two sides of the guard element  254 ″. The spring  2523 ″ acts on the second connecting rods  2522 ″ for restoring the guard element  254 ″. In this embodiment, the spring  2523 ″ is arranged between the first connecting rod  2521 ″ and the first end of the second connecting rod  2522 ″ for the restoration of the guard element. It should be conceived by the person skilled in the art that the spring  2523 ″ may also acts on the third connecting rod  2526 ″, or the guard element  254 ″. 
         [0048]    When the first connecting rod  2521 ″ is fixed on the riving knife  251 ″ by the locking knob  253 ″, the link mechanism  252 ″ enables the guard element  254 ″to move relative to the riving knife  251 ″ parallel to the plane of the blade, i.e., in the feeding direction of the blade and the perpendicular direction, thereby lifting and dropping the guard element  254 ″. 
         [0049]    In this embodiment, the guiding part  2543 ″ at the front end of the guard element  254 ″ comprises a guiding board  2563 ″ which extends obliquely and upwardly toward the front of the guard element  254 ″ in the direction parallel to the plane of the blade and extends from one side of the blade to the other in the direction perpendicular to the plane of the blade. The configuration of the guiding board  2563 ″ can enhance the ability of angle cutting of the table saw. During the angle cutting operation, once the workpiece contacts the guiding part  2543 ″, the guard element  254 ″ will move upwards, that is, raises under the action of the pushing force of the operator. 
         [0050]    In the direction perpendicular to the plane of the blade, at least one outmost edge at a side of the guiding part  2543 ″ is located outside of or flush with the outmost edge at the same side of the guard element  254 ″. As shown in  FIG. 13 , in the direction perpendicular to the plane of the blade, both of the two outmost edge  2564 ″ of the guiding part  2543 ″ flush with the two outmost edge  2565 ″ of the guard element  254 ″. Specifically, in the direction perpendicular to the plane of the blade, the two outmost edges  2564 ″ of the guiding part  2543 ″ are the two edges of the guiding board  2563 ″, and the two outmost edges  2565 ″ of the guard element  254 ″ are the two edges at the bottom of the guard element  254 ″. At least one side of the guiding part is outside of or flush with the side of the guard element, and the workpiece positioned slantways touches the side of the guiding part first while making bevel cutting, therefore, the guard element will move upwards under the action of the pushing force of the operator without lifting the guard element  254 ″ manually. 
         [0051]    Further, a blocking element  259 ″ is additionally disposed at the window  2540 ″ on the front end of the guard element  254 ″ for preventing the debris produced during the cutting operation flying toward the operator. The blocking element  259 ″ extends towards the back of the guard element  254 ″ upwardly and obliquely. The extending direction of the blocking element  259 ″ is opposite to that of the guiding board  2563 ″. 
         [0052]    In order to better control the cooling liquid in the guard element  254 ″ and prevent the cooling liquid from flowing through the front end of the guard element  254 ″, a flexible liquid retainer  2554 ″ is disposed at the front part of the flexible ring  255 ″. The flexible liquid retainer  2554 ″ extends from the inner wall of the flexible ring towards the blade, and can be configured as U-shaped to surround part of the blade. The flexible liquid retainer  2554 ″ forms a retaining edge  2555 ″ which is closer to the blade than other parts of the flexible liquid retainer  2554 ″, i.e., the inner edge of the U-shaped flexible liquid retainer  2554 ″. As shown in  FIG. 14 , the retaining edge  2555 ″ protrudes from the bottom surface of the flexible ring  255 ″ and then a height difference ΔH 1  is formed there between. This design has an advantage in that during the cutting process, the guard element  254 ″ is lifted under the action of the pushing action of the workpiece and falls on the surface of the workpiece. Under the action of gravity of the guard element  254 ″ and the spring  2523 ″, the flexible ring  255 ″ and the retaining edge  2555 ″ abut against the surface of the workpiece. Since the part of the flexible liquid retainer  2554 ′ from the inner wall of the flexible ring  255 ″ to the retaining edge  2555 ″ is deformed, a force is exerted to the retaining edge  2555 ″ so that the retaining edge  2555 ″ tightly abuts against the surface of the workpiece. Therefore, the cooling liquid is blocked in the chamber formed together by the guard element  254 ″ and the workpiece through the retaining edge  2555 ″, which effectively prevents the cooling liquid from flowing out of the front end of the guard element  254 ″ so as to remain on the surface of the workpiece. 
         [0053]    In order to prevent the cooling liquid from moving towards the back of the guard with the workpiece together and remaining on the surface of the workpiece during the cutting process, the guard assembly  25 ″ further comprises a flexible wiper  260 ″ for wiping the cooling liquid to the kerf of the workpiece so as to flow back to the tank for receiving the cooling liquid. The flexible wiper  260 ″ is arranged at the back end of the guard element  254 ″ and abuts against the surface of the workpiece. The flexible wiper  260 ″ and the flexible ring  255 ″ may be formed in one piece, or formed separately and then connected together, or used separately. As shown in  FIG. 15 , the flexible wiper  260 ″ protrudes from the bottom surface of the guard element  254 ″ and then a height difference ΔH 2  is formed therebetween. Preferably, the flexible wiper  260 ″ has a V-shaped wiping rib  261 ″ at the side facing to the workpiece. The opening of the wiping rib  261 ″ faces to the blade, and the wiping rib  261 ″ protrudes from the bottom surface of the guard element  254 ″. This design has an advantage in that during the cutting process, the guard element  254 ″ falls on the surface of the workpiece, and under the action of gravity of the guard element  254 ″ itself and the spring  2523 ″, the wiping rib  261 ″ tightly abuts against the surface of the workpiece. When the operator pushes the workpiece towards the blade, the workpiece is cut by the blade and moves towards the back end of the guard element  254 ″, and the wiping rib  261 ″ can wipe the cooling liquid on the surface of the workpiece to the guiding plate  251 ′, thereby effectively preventing the cooling liquid from flowing away from the back end of the guard element  254 ″ so as to remain on the surface of the workpiece which has been cut. 
         [0054]    With the liquid retainer and the wiper arranged on the front end and the back end of the guard, respectively, this embodiment can effectively prevent the cooling liquid from flowing away from the front end and the back end of the guard so as to retain on the surface of the workpiece, and also control the cooling liquid within the guard element better to ensure the cleanness of the surface of the workpiece. 
         [0055]    The cooling liquid guiding system of the table saw is not to be limited to the structures indicated by the contents of the above embodiments and drawings. Rather, obvious changes, replacements and modifications for the shape and position of the members based on this disclosure are to be considered as falling within the protection scope of the invention as defined by the following claims.