Abstract:
A power tool includes a table. A shaft is disposed on the table and has an axis. A support housing supporting a motor and a working tool driven by the motor is disposed on the shaft adjacent to the table. The support housing is axially movable along the shaft and being laterally pivotable about an axis of rotation. A locking mechanism is further provided for locking the support housing at a predetermined lateral position, wherein the locking mechanism may include a handle disposed on the shaft, the handle being rotatable in two directions with respect to the table, such that, upon rotation of the handle in both directions from a neutral position, the handle urges the support housing into contact with the table. The shaft may be rotatable relative to the table. The locking mechanism may further include a first camming surface disposed on the table and a second camming surface disposed on the shaft and engaging the first camming surface. Alternatively, the shaft may include a first surface having a first thread disposed thereon in a first orientation, and a second surface having a second thread disposed thereon in a second orientation, the first and second thread intersect forming a V-shaped thread. The table may then include at least one protrusion slidable along the first and second threads.

Description:
[0001]    This application is a continuation-in-part of U.S. Ser. No. 08/803,406, filed Feb. 20, 1997, which is in turn a continuation-in-part of U.S. Ser. No. 08/761,730, filed Dec. 5, 1996, which in turn claims the benefit of U.S. Provisional Application No. 60/008,512, filed Dec. 15, 1995, now abandoned. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to compound miter saws or other power operated equipment or machinery utilizing a cutter for performing working operations on a workpiece. More particularly, the present invention relates to improvements in the bevel lock mechanism for the bevel adjustment for such power operated equipment.  
         BACKGROUND OF THE INVENTION  
         [0003]    Saws and other apparatuses designed for cutting or performing other working operations on a workpiece typically require adjustment mechanisms for moving the saw blade or cutting tool into an angular relationship to the workpiece. Examples of such equipment include cross-cut compound miter saws which are adapted for allowing the user to selectively move the saw blade into any of a number of positions or modes for square cutting, miter cutting, bevel cutting, or compound miter cutting where a combination miter angle and bevel angle are cut. In addition, some operations, such as dado cutting or shaping operations, for example, require the use of saw blades or other cutting or working devices of different shapes or sizes to be substituted for one another in order to perform the desired operation on the workpiece, whether the workpiece is composed of wood, plastic, metal or other materials.  
           [0004]    In order to allow for the adjustment in the miter and the bevel angle, the saw blade, cutter or other working device is angularly adjustable with respect to a horizontal base and a vertical fence against which the workpiece is positioned. The miter adjustment allows the saw blade, cutter or other working device to move angularly with respect to the vertical fence while maintaining perpendicularity with the horizontal base. The bevel adjustment allows the saw blade, cutter or other working device to move angularly with respect to the horizontal base while maintaining perpendicularity with the vertical fence. At times it may be desirable to cut a combination miter angle and bevel angle by simultaneously adjusting the angularity of the blade with respect to both the horizontal base and the vertical fence.  
           [0005]    Once the saw blade, cutter or other working device has been adjusted to the desired position with respect to the horizontal base and the vertical fence, locking mechanisms for the miter and bevel adjustment must be activated in order to prohibit movement of the saw blade, cutter or other working device with respect to the base and fence while the cutting operation is performed. These locking mechanisms need to be easily activated, adjustable and quick acting in order to optimize the efficiency of the cutting apparatus and provide convenience to the operator of the apparatus.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, an improved bevel lock is employed in a power tool. The power tool comprises a table. A shaft is disposed on the table. The power tool also has a support housing supporting a motor and a working tool driven by the motor. The support housing is disposed on the shaft adjacent to the table and is axially movable along the shaft and laterally pivotable about an axis of rotation. In addition, the power tool has a locking mechanism for locking the support housing at a predetermined lateral position, wherein the locking mechanism comprises a handle disposed on the shaft. The handle is rotatable in two directions with respect to the table, such that, upon rotation of the handle on either direction from a neutral position, the handle urges the support housing into locking contact with the table.  
           [0007]    Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:  
         [0009]    [0009]FIG. 1 is a front perspective view of a sliding compound miter saw in accordance with the present invention;  
         [0010]    [0010]FIG. 2 is a front elevational view of the sliding compound miter saw shown in FIG. 1;  
         [0011]    [0011]FIG. 3 is a rear elevational view of the sliding compound miter saw shown in FIGS. 1 and 2;  
         [0012]    [0012]FIG. 4 is a side elevational view of the sliding compound miter saw shown in FIGS. 1 through 3;  
         [0013]    [0013]FIG. 5 is an exploded perspective view of a first embodiment of the bevel stop mechanism in accordance with the present invention;  
         [0014]    [0014]FIG. 6 is an assembled perspective view, partially in cross-section of the first embodiment of the bevel stop mechanism shown in FIG. 5;  
         [0015]    [0015]FIG. 7 is a cross-sectional side view of the first embodiment of the bevel stop mechanism shown in FIG. 5;  
         [0016]    [0016]FIG. 8 is an end view of the base or table assembly illustrating a first embodiment of the adjustment feature provided for the bevel stop mechanism shown in FIG. 5;  
         [0017]    [0017]FIG. 9 is an exploded perspective view of a second embodiment of the bevel stop mechanism in accordance with the present invention;  
         [0018]    [0018]FIG. 10 is a cross-sectional side view of the second embodiment of the bevel stop mechanism shown in FIG. 9;  
         [0019]    [0019]FIGS. 11A and 11B are cross-sectional side views of a third and fourth embodiments of the bevel stop mechanism;  
         [0020]    [0020]FIG. 12 is a cross-sectional rear view along line A-A of FIG. 11B;  
         [0021]    [0021]FIG. 13 is a top view of the shaft along line B-B of FIG. 12;  
         [0022]    [0022]FIG. 14 is a cross-sectional side view of a fifth embodiment of the bevel stop mechanism;  
         [0023]    [0023]FIG. 15 is a cross-sectional rear view along line C-C of FIG. 14;  
         [0024]    [0024]FIG. 16 is a cross-sectional side view of a sixth embodiment of the bevel stop mechanism;  
         [0025]    [0025]FIG. 17 is a cross-sectional side view of a seventh embodiment of the bevel stop mechanism;  
         [0026]    [0026]FIG. 18 is a cross-sectional side view of an eighth embodiment of the bevel stop mechanism; and  
         [0027]    [0027]FIG. 19 is a cross-sectional side view of a ninth embodiment of the bevel stop mechanism.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in FIGS. 1 through 4 an exemplary sliding compound miter saw incorporating a bevel stop mechanism according to the present invention, shown merely for the purposes of illustration, and designated generally by the reference numeral  10 . One skilled in the art will readily recognize from the following description, taken in conjunction with the accompanying drawings and claims, that the principles of the present invention are equally applicable to sliding compound miter saws, compound miter saws, chop saws, radial arm saws, table saws, jigsaws, scroll saws, or other saws of types other than that shown for purposes of illustration in the drawings. Similarly, one skilled in the art will readily recognize that the principles of the bevel stop mechanism according to the present invention are also applicable to other types of powered or unpowered equipment for performing an operation on a workpiece. Such equipment includes, but is not limited to, dado saws, spindle shapers or sanders, or other types of powered or unpowered devices that would benefit from the cam locking mechanism of the present invention.  
         [0029]    Referring primarily to FIGS. 1 through 4, sliding compound miter saw  10  comprises a base assembly  12 , a table assembly  14 , a unique housing assembly  16 , a saw blade  18 , a blade guard  20 , a motor  22  drivingly connected to saw blade  18 , a handle  24  and a fence assembly  26 . Table assembly  14  is secured to base assembly  12  such that it can be rotated in order to provide adjustment for miter cutting. The rotation of table assembly  14  changes the angle of saw blade  18  relative to fence assembly  26  but maintains the perpendicularity of saw blade  18  with table assembly  14 . A locking mechanism  28  can be activated in order to lock table assembly  14  to base assembly  12 .  
         [0030]    Housing assembly  16  is secured to table assembly  14  such that it can be pivoted with respect to table assembly  14  in order to provide adjustment for bevel cutting. As can be appreciated by one skilled in the art, the adjustments for mitering and beveling can be separate or they can be adjusted simultaneously in order to provide a compound miter and bevel cut. The pivoting of housing assembly  16  changes the angle of saw blade  18  relative to table assembly  14  but maintains the perpendicularity of saw blade  18  with respect fence assembly  26 . A locking mechanism  30  can be activated in order to lock housing assembly  16  to table assembly  14  at any desired bevel angle.  
         [0031]    Referring to FIGS. 1 through 5, housing assembly  16  includes support housing  32 , which mounts a pair of support arms  34  for sliding movement with respect to housing  32 . Saw blade  18 , blade guard  20 , motor  22  and handle  24  are all mounted to a drive housing  36  which is pivotably secured to support arms  34 . The pivoting of drive housing  36  downward towards table assembly  14  operates to open blade guard  20  and cut a workpiece which is supported by table assembly  14  and fence assembly  26 . The sliding movement of support arm  34  relative to housing  32  permits drive housing  36  and thus saw blade  18  to be pulled through the workpiece when the size of the workpiece exceeds the cutting width of saw blade  18 .  
         [0032]    Referring now to FIGS. 5 through 8, support housing  32  is pivotably supported with respect to table assembly  14  on a steel shaft  40  which is secured to table assembly  14  and extends rearwardly from table assembly  14  to define a pivot axis  42  for support housing  32 . Shaft  40  is inserted into a complimentary bore  44  located within table assembly  14  and is secured in place using a cross pin  46  which extends through a bore  47  extending through shaft  40  and a corresponding set of bores  48  located within table assembly,  14  and being generally perpendicular to and extending into bore  44 . The end of shaft  40  opposite to the end defining bore  46  includes a threaded stub  50  for retaining and adjusting locking mechanism  30  as will be described later herein.  
         [0033]    Persons skilled in the art will recognize that the shaft  40  can be fixed to the table assembly  14  using other means. For example, the shaft  40  can be soldered or screwed unto the table assembly  14 . Similarly, the shaft  40  can be built into the table assembly  14  as a fixed casting.  
         [0034]    Locking mechanism  30  comprises a cam  52 , a handle  54 , a thrust bearing  55 , a plurality of washers  56  and a locknut  58 . Once support housing  32  is slidingly and pivotably received on shaft  40 , cam  52  is slidingly positioned on shaft  40  adjacent support housing  32 . Cam  52  includes a D-shaped through bore  60  which mates with a corresponding D-shaped portion  62  of shaft  40  such that cam  52  is allowed to move axially along portion  62  of shaft  40  but rotation of cam  52  with respect to shaft  40  is prohibited. Cam  52  further includes an angular camming surface  64  having a plurality of ramps which is located on the radial surface of cam  52  which is opposite to support housing  32 . Camming surface  64  is designed to mate with handle  54  as will be described later herein.  
         [0035]    Handle  54  is slidingly and rotatably positioned on shaft  40  adjacent to and outboard of cam  52 . Handle  54  includes an angular camming surface  66  having a plurality of ramps which mates with angular camming surface  64  on cam  52 . Support housing  32 , cam  52  and handle  54  are retained on shaft  40  by thrust washer  55 , the plurality of washers  56  and locknut  58  which is threadingly received on stub  50  of shaft  40 .  
         [0036]    When angular camming surface  64  and angular camming surface  66  are in full contact with each other as shown in FIG. 7, support housing  32  is free to pivot on shaft  40  to change the bevel angle of saw blade  18 . Once the desired bevel angle has been set, handle  54  is rotated with respect to shaft  40 . Rotation of handle  54  mis-aligns camming surfaces  64  and  66  pushing support housing  32  and cam  52  axially along shaft  40 . Support housing  32  contacts table assembly  14  and continued rotation of handle  54  forces support housing  32  into table assembly  14  locking the two components together. The locking of the two components together can be accomplished by rotating handle  54  in either a clockwise or a counter clockwise direction on order to misalign camming surfaces  64  and  66 . This bi-directional locking ability of handle  54  simplifies the adjustment of the bevel angle on opposite sides of center. An indicator plate  68  is bolted to support housing  32  to allow the user to set a specific bevel angle. Indicator plate  68  is provided with a pair of slots which allow for the zero adjustment of plate  68  as is well known in the art.  
         [0037]    Persons skilled in the art will recognize that other camming surfaces on handle  54  and cam  52  may be provided to obtain the result described above. Persons skilled in the art are referred to the parent applications, which are hereby incorporated by reference.  
         [0038]    For example, FIGS. 9 and 10 illustrate a second embodiment of the bevel locking mechanism is illustrated. Unlike the prior embodiment, the handle  54  is provided with a camming surface  66   a  which mates with camming surface  64   a  on cam  52   a . As shown in FIG. 9, the camming surface  66   a  is provided with peaks  66   p  and valleys  66   v . Camming surface  64   a  has corresponding peaks and valleys in order to mate with camming surface  66   a . Having the multiple peaks and valleys helps in evenly distributing the camming force. Nevertheless, the arrangement and operation of the second embodiment is similar to the one illustrated in FIGS.  5  to  7 . In addition, the operator is still able to lock the housing  32  and the table assembly  14  together by rotating handle  54  in either a clockwise or a counter clockwise direction.  
         [0039]    Furthermore, persons skilled in the art will recognize that cam  52  may be integrated with the support housing  32 . This is especially advantageous as less parts are necessary for manufacture, while still allowing the operator to lock the housing  32  and the table assembly  14  together by rotating handle  54  in either a clockwise or a counter clockwise direction.  
         [0040]    [0040]FIGS. 11A to  13  illustrate a third and fourth embodiments of the bevel lock mechanism, where like numerals refer to like parts with like functions. In both embodiments the shaft  40  is provided with a “double screw” portion  102 . As shown in FIG. 13, on one side of the double screw portion  102 , a set of threads  101   a  are disposed thereon in a first orientation. In addition, on the other side of the double screw portion  102 , a second set of threads  101   b  are disposed thereon in a second orientation. The threads  101   a  and  101   b  intersect to form V-shaped threads  101 . Preferably, the resulting threads  101  will have a low pitch, so that more travel along the axis of the rod can be obtained with a smaller amount of rotation.  
         [0041]    The handle  54   a  has protrusions  105  to engage the threads  101 , as shown in FIG. 14A. These protrusions  105  slide along the threads  101 , as the handle  54   a  is rotated, forcing the handle  54   a  to travel along shaft  40 . This in turn forces the handle  54   a  towards the support housing  32 , thus clamping the support housing  32  in place between handle  54   a  and table assembly  14 . Accordingly, the rotational motion of handle  54   a  is translated into a linear motion along shaft  40 , causing the clamping action.  
         [0042]    As shown in FIGS. 11A and 11B, the protrusions  105  preferably match the profile of the threads  101 , allowing travel along threads  101 . Accordingly if the thread  101  is rounded, the protrusions  105  are preferably rounded. Persons skilled in the art will nevertheless recognize that any profile of protrusions  105  will be acceptable so long as the protrusions  105  can slide along the threads  101 .  
         [0043]    Preferably, the protrusions  105  are disposed on a button  100 , as shown in FIG. 11B. It is also advantageous to provide a spring  104  to bias the button  100  into contact with the double screw portion  102 . Accordingly, in order to install handle  54   a , an operator need only push gripping portion  100   a  of the button  100 , slide the handle  54   a  along the shaft  40 , and release button  100 .  
         [0044]    People skilled in the art will recognize that means other than the spring  104  will also allow easy installation and removal of handle  54   a . For example, as shown in FIG. 16, the handle  54   a  may include a thread engaging portion  54   b , held in place by a plug  54   c . Accordingly, in order to install handle  54   a , an operator need only slide the handle  54   a  along the shaft  40  and insert the thread engaging portion  54   b , so that it engages the threads  101 . The operator can then insert the plug  54   c  to hold the thread engaging portion  54   b  in place.  
         [0045]    [0045]FIGS. 14 and 15 show yet another embodiment of the bevel lock mechanism. Unlike in the previous embodiments, the locking shaft and the pivot axis are not the same. As shown in FIG. 14, support housing  32  is pivotably supported with respect to table assembly  14  on a shaft  110  which is fixedly secured to table assembly  14  via threads  111 . Persons skilled in the art will recognize that other means for fixing the shaft  110  to the table assembly  14  are available. The shaft  110  extends rearwardly from table assembly  14  to define a pivot axis  142  for support housing  32 . Preferably, the shaft  110  has a threaded portion  112 . A thrust bearing  551 , a washer  561  and a locknut  581  are disposed on the shaft  110  in order to retain the housing  32 .  
         [0046]    In addition, locking shaft  401  is inserted into a complimentary bore  441  located within table assembly  14  and is secured in place using a cross pin  461  which extends through a bore  471  extending through shaft  401  and a corresponding set of bores  481  located within table assembly  14  and being generally perpendicular to and extending into bore  441 . The end of shaft  401  opposite to the end defining bore  461  includes a threaded stub  501  for retaining and adjusting a locking mechanism  30 , such as the ones described above. As shown in FIG. 14, a slot  140  is provided in the table assembly  14 . The shaft  401  is disposed through the slot  140  so that, as the bevel angle is changed, the shaft  401  can travel along the slot  140 .  
         [0047]    Persons skilled in the art will see that the locking shaft  401  is substantially parallel to shaft  110 . However, those persons should recognize that the disclosed embodiment is for exemplary purposes only and that the shafts  401  and  110  need not be parallel to each other.  
         [0048]    As shown in FIG. 14, the locking mechanism  30  shown in FIGS.  5  to  7  can be disposed on the locking shaft  401  and used as described above. However, persons skilled in the art will recognize that any of the different embodiments described above for the locking mechanism can be used instead.  
         [0049]    FIGS.  17  to  19  illustrate different embodiments of locking mechanism  30 . Unlike the previous embodiments, shaft  40  is not fixedly attached to the table assembly  14 . Instead, the shaft  40  is rotatable. In addition, the handle  54   b  is not slidingly and rotatably positioned on shaft  40 . Instead, handle  54   b  is fixedly attached to or integrated with shaft  40  at the outer end of the shaft. Preferably a key  40   k  is provided on the shaft  40  to mesh with a groove  54   g  in the handle  54   b , or vice versa, to ensure rotational movement of both shaft  40  and handle  54   b . Thus, if the operator rotates the handle  54   b , the shaft  40  moves accordingly.  
         [0050]    Handle  54   b  may be fixedly attached to shaft  40  via a locknut  58 .  
         [0051]    Furthermore, handle  54   b  does not have camming surfaces  66  contacting the camming surfaces of cam  52 ′ like prior embodiments. This is because handle  54   b  does not contact cam  52 ′ as cam  52 ′ is not disposed between handle  54   b  and the support housing  32 . Instead, a cam end  200  is fixedly attached to or integrated with the shaft  40  at its other end, as shown in FIG. 17. Preferably a key  40   kk  is provided on the shaft  40  to mesh with a groove  200   g  in the cam end  200 , or vice versa, to ensure rotational movement of both shaft  40  and cam end  200 . Thus, if the operator rotates the handle  54   b , the shaft  40  and cam end  200  move accordingly.  
         [0052]    As mentioned above, cam  52 ′ is not disposed between handle  54   b  and support housing  32 , as in prior embodiments. Instead, cam  52 ′ is disposed in table assembly  14  to contact cam end  200 . Preferably, cam  52 ′ is integrated with table assembly  14 . Cam  52 ′ preferably does not rotate. Cam  52 ′ may include an angular camming surface  64 ′ having a plurality of ramps which is located on the radial surface of cam  52  which is nearest cam end  200 . Camming surface  64  is designed to mate with a camming surface  200   s  on cam end  200  as will be described later herein.  
         [0053]    When angular camming surface  64  and angular camming surface  200   s  are in full contact with each other as shown in FIG. 17, support housing  32  is free to pivot on shaft  40  to change the bevel angle of saw blade  18 . Once the desired bevel angle has been set, handle  54   b  is rotated. Rotation of handle  54   b  (and thus shaft  40  and cam end  200 ) mis-aligns camming surfaces  64  and  200   s  pushing shaft  40  towards table assembly  14 . Support housing  32  contacts handle  54   b  and table assembly  14  and continued rotation of handle  54   b  forces support housing  32  into table assembly  14  locking the two components together. The locking of the two components together can be accomplished by rotating handle  54   b  in either a clockwise or a counter clockwise direction on order to misalign camming surfaces  64  and  200   s . This bi-directional locking ability of handle  54   b  simplifies the adjustment of the bevel angle on opposite sides of center.  
         [0054]    Persons skilled in the art will recognize that the different camming surfaces to be used on handle  54  and cam  52  in the different embodiments disclosed in the parent applications may also be used on cam end  200  and cam  52 ′ to obtain the result described above. Again, persons skilled in the art are referred to the parent applications, which are hereby incorporated by reference.  
         [0055]    [0055]FIGS. 18 and 19 also illustrate different embodiments of the bevel lock mechanism, where like numerals refer to like parts with like functions. In these embodiments, the shaft  40  is rotatable and handle  54   b  is fixedly attached to or integrated with shaft  40  at the outer end of the shaft. Preferably a key  40   k  is provided on the shaft  40  to mesh with a groove  54   g  in the handle  54   b , or vice versa, to ensure rotational movement of both shaft  40  and handle  54   b . Thus, if the operator rotates the handle  54   b , the shaft  40  moves accordingly.  
         [0056]    A double screw portion  102  is provided at the other end of the shaft  40 . Again, as in FIG. 13, on one side of the double screw portion  102 , a set of threads  101   a  are disposed thereon in a first orientation. In addition, on the other side of the double screw portion  102 , a second set of threads  101   b  are disposed thereon in a second orientation. The threads  101   a  and  101   b  intersect to form V-shaped threads  101 . Preferably, the resulting threads  101  will have a low pitch, so that more travel along the axis of the rod can be obtained with a smaller amount of rotation.  
         [0057]    The table assembly  14  has protrusions  205  to engage the threads  101 , as shown in FIG. 18. These protrusions  205  slide along the threads  101 , as the handle  54   b  (and thus shaft  40  and screw portion  102 ) is rotated, the handle  54   b  and shaft  40  travel towards table assembly  14 . This in turn forces the handle  54   b  towards the support housing  32 , thus clamping the support housing  32  in place between handle  54   b  and table assembly  14 . Accordingly, the rotational motion of handle  54   a  is translated into a linear motion, causing the clamping action.  
         [0058]    As shown in FIGS. 18 and 19, the protrusions  205  preferably match the profile of the threads  101 , allowing travel along threads  101 . Accordingly if the thread  101  is rounded, the protrusions  205  are preferably rounded. Persons skilled in the art will nevertheless recognize that any profile of protrusions  205  will be acceptable so long as the protrusions  205  can slide along the threads  101 .  
         [0059]    Preferably, the protrusions  205  are disposed on a thread engaging portion  206 , as shown in FIG. 19, held in place by a plug  207 . Accordingly, in order to install shaft  40 , an operator need only the shaft  40  into the table assembly  14  and insert the thread engaging portion  206 , so that it engages the threads  101 . The operator can then insert the plug  207  to hold the thread engaging portion  206  in place.  
         [0060]    The above detailed description describes different embodiments of the present invention. Persons skilled in the art may recognize other alternatives to the means disclosed herein, such as using a knob instead of handle  54 . However, all these additions and/or alterations are considered to be equivalents of the present invention.