Abstract:
A multi-link miter saw includes a base, a table supported on the base, a supporting unit connected to the table, a linkage unit connected to the supporting unit, a cantilever arm unit including a cantilever arm pivotally connected to the linkage unit and a connection member pivotally connected between the cantilever arm and the linkage unit for enabling the cantilever arm to be driven by the linkage unit and the connection member to move along a horizontal axis between the rear edge and front edge of the base, and a cutting unit pivotally connected to the cantilever arm unit. Based on the arrangement of the linkage unit and the cantilever arm unit, the cutting unit can be moved smoothly relative to the table, thus enhancing operation stability.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to processing machinery, and more particularly, to a multi-link miter saw. 
     2. Description of the Related Art 
     A conventional slider-based miter saw is known comprising a base, a table mounted at the base, a support frame connected to a rear side of the table, a slider unit linearly movable along the support frame, and a cutting unit connected to the slider unit. Subject to the mating arrangement between the support frame and the slider unit, the cutting unit can be pulled forwards to perform a cutting stroke, thus achieving a cutting operation. 
     The above prior art slider-based miter saw is applicable to processing operations that require a cutting stroke. However, because the slider unit needs to make a back and forth stroke, the surroundings around the work area must be kept clear to avoid interference. Thus, this design of such a slider-based miter saw requires a lot of installation space. Further, because the cutting unit has a heavy weight, the slider unit can be vibrated relative to the support frame during the operation, thus resulting in noises. 
     U.S. Pat. No. 8,499,672 discloses a power miter saw, which comprises a saw base, a table rotatably connected to the saw base, a miter arm assembly for angularly positioning the table relative to the saw base, a saw blade and motor assembly operatively connected to the table, and a linear guide mechanism attached to the table and being configured to support the saw blade and motor assembly and enable movement of the assembly along a predetermined linear path in either forward or rearward directions. During an extending or receiving action of the miter arm assembly, the linear guide mechanism is driven to extend out or retract horizontally. However, due to single point pivot connection arrangement of the miter arm assembly and the linear guide mechanism relative to the saw base, the overall structure is disadvantageously less stable during the cutting stroke of the cutting unit. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a multi-link miter saw, which has a simple structure and greatly enhances structural stability. 
     To achieve this and other objects of the present invention, a multi-link miter saw comprises a base, a table, a supporting unit, a linkage unit, a cantilever arm unit, and a cutting unit. The base comprises a front edge and an opposing rear edge. The table is mounted at the base, comprising an axle holder disposed corresponding to the rear edge. The supporting unit is disposed corresponding to the rear edge, and connected to the axle holder of the table. The linkage unit is connected to the supporting unit and swingeable between the rear edge and front edge of the base. The cantilever arm unit is pivotally connected to the linkage unit, comprising a cantilever arm pivotally connected to the linkage unit and a connection member pivotally connected between the cantilever arm and the linkage unit. Thus, the cantilever arm can be driven by the linkage unit and the connection member to move along a horizontal axis between the rear edge and front edge of the base. The cutting unit comprises a saw blade holder pivotally connected to the cantilever arm unit, and a saw blade pivotally mounted in the saw blade holder. 
     Based on the arrangement of the linkage unit and the cantilever arm unit, the cutting unit can be moved smoothly relative to the table, thus advantageously enhancing operation stability. 
     Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is perspective view of a multi-link miter saw in accordance with the present invention. 
         FIG. 2  is an exploded perspective view of the multi-link miter saw in accordance with the present invention. 
         FIG. 3  is a side elevation view of the present invention, illustrating the cutting unit in a received position. 
         FIG. 4  is a side elevation view of the present invention, illustrating the cutting unit in a ready position for cutting. 
         FIG. 5  is similar to  FIG. 4 , illustrating the cutting unit moved forwards according to the cutting stroke. 
         FIG. 6  is similar to  FIG. 5 , illustrating the cutting unit biased relative to the table into a cutting position. 
       It should be noted that the drawing figures are not necessarily drawn to scale, but instead are drawn to provide a better understanding of the components thereof, and are not intended to be limiting in scope, but rather to provide exemplary illustrations. It should further be noted that the figures illustrate an exemplary embodiment of the present invention and the components thereof, and in no way limits the structures, configurations and components thereof according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1, 2 and 3 , a multi-link miter saw in accordance with the present invention is shown. The multi-link miter saw comprises a base  10 , a table  20 , a supporting unit  30 , a linkage unit  40 , a cantilever arm unit  50 , and a cutting unit  60 . 
     The base unit  10  comprises a front edge  11 , and a rear edge  12  disposed opposite to the front edge  11 . 
     The table  20  is rotatably mounted on the base  10 , and comprises an axle holder  21  corresponding to the rear edge  12  of the base unit  10 . 
     The supporting unit  30  is rotatably connected to the axle holder  21  of the table  20  corresponding to the rear edge  12  of the base unit  10 . 
     The linkage unit  40  is a four-bar linkage mechanism connected to the supporting unit  30  and movable between the rear edge  12  and front edge  11  of the base unit  10 . In this embodiment, the linkage unit  40  comprises a first link  41  connected to the supporting unit  30 , a second link  42  pivotally connected to the first link  41 , a third link  43  corresponding to the second link  42  and pivotally connected to the first link  41 , and a fourth link  44  pivotally connected between the second link  42  and the third link  43 . 
     The first link  41  is an elongated bar comprising a first pivot-connection portion  411  disposed adjacent to the axle holder  21  and an opposite second pivot-connection portion  412  pivotally connected to the second link  42 . 
     The second link  42  comprises a lower rotating portion  421  pivotally connected to the second pivot-connection portion  412 , and an upper rotating portion  422  disposed opposite to the lower rotating portion  421 . 
     The third link  43  comprises a lower pivot-connection portion  431  pivotally connected to the first pivot-connection portion  411 , an upper pivot-connection portion  432  disposed opposite to the lower pivot-connection portion  431  and pivotally connected to the fourth link  44 , and a middle pivot-connection portion  433  disposed between the lower pivot-connection portion  431  and the upper pivot-connection portion  432 . 
     The fourth link  44  comprises a first pivoting portion  441  pivotally connected to the upper rotating portion  422 , a second pivoting portion  442  disposed opposite to the first pivoting portion  441  and pivotally connected to the upper pivot-connection portion  432 , and a coupling portion  443  disposed between the first pivoting portion  441  and the second pivoting portion  442 . 
     The cantilever arm unit  50  is pivotally connected to the linkage unit  40 , comprising a cantilever arm  51  pivotally connected to the linkage unit  40  and a connection member  52  pivotally connected between the cantilever arm  51  and the linkage unit  40 . The cantilever arm  51  is drivable by the linkage unit  40  and the connection member  52  to move along a horizontal axis X between the rear edge  12  and front edge  11  of the base unit  10 . The cantilever arm  51  is pivotally connected to the fourth link  44  of the linkage unit  40 . The connection member  52  is pivotally connected between the cantilever arm  51  and the middle pivot-connection portion  433  of the third link  43  of the linkage unit  40 . The cantilever arm  51  comprises an interlocking portion  511  pivotally connected to the coupling portion  443  of the fourth link  44 , a pivot bearing portion  512  disposed opposite to the interlocking portion  511  for the connection of the cutting unit  60  pivotally, a pivot portion  513  disposed between the interlocking portion  511  and the pivot bearing portion  512 , an actuation portion  514  disposed between the pivot bearing portion  512  and the pivot portion  513 , a first sidewall  515  and an opposing second sidewall  516  disposed around the pivot bearing portion  512 , a substantially L-shaped panel  517  connected between the first sidewall  515  and the second sidewall  516 , and an accommodation chamber  518  surrounded by the first sidewall  515 , the second sidewall  516  and the L-shaped panel  517 . The connection member  52  is pivotally connected between the middle pivot-connection portion  433  of the third link  43  of the linkage unit  40  and the pivot portion  513  of the cantilever arm  51 . 
     The cutting unit  60  comprises a saw blade holder  61  pivotally connected to the cantilever arm unit  50 , a saw blade  62  pivotally mounted in the saw blade holder  61 , a saw blade guard  63  pivotally connected to the saw blade holder  61  around the saw blade  62 , a pull bar  64  pivotally connected between the actuation portion  514  and the saw blade guard  63 , and a handle  65  positioned relative to the saw blade holder  61 . The saw blade holder  61  comprises a side end portion  611  accommodated in the accommodation chamber  518  and pivotally connected to the pivot bearing portion  512 . Thus, the side end portion  611  is disposed between the first sidewall  515  and the second sidewall  516 . 
     As illustrated in  FIG. 3 , when the saw blade  62  is disposed in a received position after a cutting operation is performed (i.e., at the end of the cutting stroke), the saw blade  62  of the cutting unit  60  is disposed in close proximity to the table  20  and the axle holder  21 ; the second link  42  and the connection member  52  are substantially disposed vertically relative to the horizontal axis X; the third link  43  is disposed in a backwardly and upwardly tilted manner relative to the rear edge  12 ; the cantilever arm  51  of the cantilever arm unit  50  substantially extends along the horizontal axis X. 
     When the operator is going to start a cutting operation, as shown in  FIG. 4 , the operator can operate the handle  65  to lift the cutting unit  60  (in the direction indicated by the arrowhead) and to further bias the side end portion  611  of the cutting unit  60  upwardly relative to the pivot bearing portion  512 . Due to the pull bar  64  being pivotally connected between the actuation portion  514  and the saw blade guard  63 , the pull bar  64  is forced to bias the saw blade guard  63  relative to the saw blade holder  61  at this time such that the saw blade  62  is shielded. Thus, at this time, the cutting unit  60  is located in a ready position which is away from the table  20 . 
     Thereafter, as shown in  FIG. 5 , the operator can carry the handle  65  forwardly along the horizontal axis X, thus moving the cutting unit  60  in the cutting stroke (in the direction indicated by the arrowhead). At this time, the cantilever arm  51  can drive the fourth link  44  of the linkage unit  40  and the connection member  52 . Further, the fourth link  44  can be rotated on the axis of the coupling portion  443  through  180 ° to move the second link  42  forwardly and upwardly in a slightly tilted manner from the rear edge  12 . Thus, the third link  43  and the fourth link  44  can be kept in a vertical position, and the cantilever arm  51  can be moved horizontally along the horizontal axis X, such that the cutting unit  60  is located in the ready position. 
     Thereafter, as shown in  FIG. 6 , when the operator biases the cutting unit  60  downwards (in the direction indicated by the arrowhead) to turn the side end portion  611  of the cutting unit  60  downwardly about the axis of the pivot bearing portion  512 , the pull bar  64  is forced to bias the saw blade guard  63  relative to the saw blade holder  61 , thereby unshielding the saw blade  62 . Thus, the saw blade  62  can be moved toward the workpiece (not shown) at the table  20 . 
     When the operator exerts a force on the handle  65  in the direction toward the workpiece, the saw blade  62  is forced to cut the workpiece, and the multi-link miter saw can be returned to the configuration shown in  FIG. 3  subject to linking between the cantilever arm  51  and the linkage unit  40 . 
     As illustrated in  FIGS. 3-6 , subject to cooperation between the linkage unit  40  and the cantilever arm unit  50 , the multi-point pivot connection arrangement between the cantilever arm  51  and connection member  52  of the cantilever arm unit  50  and the linkage unit  40  ensures a high level of structural stability during the movement of the cutting unit  60  in the cutting stroke. Thus, the cutting unit  60  can be operated to cut the workpiece stably without vibrations. 
     In conclusion, the invention makes use of the overall coordination, ensuring a high level of operating smoothness and stability and achieving the expected objects. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.