Abstract:
A compound miter saw includes a unique table assembly which incorporates a table locking mechanism and a detent override mechanism. The lock mechanism incorporated into the table assembly is movable between two positions. The first position locks the table to the miter saw and the second position permits rotation of the table. The detent override mechanism is normally engaged such that it will releasably hold the table in one of a plurality of popular miter angles. The detent override mechanism allows the operator to disengage the detent system to avoid the holding of the table during its rotation.

Description:
FIELD OF THE INVENTION 
     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 table assembly for the miter adjustment for such power operated equipment. The table assembly includes a miter detent override for allowing adjustment of the miter angle without interference from the detent system. 
     BACKGROUND OF THE INVENTION 
     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. An example of such equipment includes 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 and bevel 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. 
     In order to allow for the adjustment in miter and bevel angles, 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 and bevel by simultaneously adjusting the angularity of the blade with respect to both the horizontal base and the vertical fence. 
     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 
     In accordance with the present invention, an improved table assembly incorporating a miter locking mechanism with a miter detent override mechanism is employed. The locking mechanism includes an axially extending locking rod which has a two positional lever assembly at one end and a guide/locking bracket at the opposite end. The guide/locking bracket is utilized to guide the movement of the locking rod as well as to lock the table at the desired miter angle. The lever assembly is movable between a first position where the miter table is locked to a base of the table assembly at a specified position and a second position where the miter table is free to rotate with respect to the base of the table assembly. The miter detent override mechanism includes a detent spring, a detent spring actuator and a plurality of detent slots with each slot being located at one of the various popular miter angles. When the detent spring is located within one of the detent slots, the miter table is releasable held at a respective one of these popular miter angles. 
     The detent spring actuator is provided to cause the detent spring to bypass the various detent slots provided at the various popular miter angles, thus allowing for adjustment of the table to a position in between the miter detent slots. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a front perspective view of a sliding compound miter saw in accordance with the present invention; 
     FIG. 2 is a front elevational view of the sliding compound miter saw shown in FIG. 1; 
     FIG. 3 is a rear elevational view of the sliding compound miter saw shown in FIGS. 1 and 2; 
     FIG. 4 is a side elevational view of the sliding compound miter saw shown in FIGS. 1 through 3; 
     FIG. 5 is an assembled perspective view, partially in cross-section of the table assembly shown in FIGS. 1 through 4; 
     FIG. 6 is a perspective view of the miter locking mechanism and miter detent override mechanism in accordance with the present invention; 
     FIG. 7 is a perspective view of the miter locking mechanism shown in FIG. 6; 
     FIG. 8 is a perspective view of the miter detent override mechanism shown in FIG. 6; and 
     FIGS. 9A-9D are cross-sectional side views of the miter locking mechanism and the miter detent override mechanism in accordance with the present invention showing the mechanisms in their various positions. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     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 table assembly in accordance with 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 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 table assembly 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 table assembly of the present invention. 
     Referring primarily to FIGS. 1 through 4, sliding compound miter saw  10  comprises a base assembly  12 , a table assembly  14 , a 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 . 
     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 is known in the art. 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 fence assembly  26 . A locking mechanism  30  can be activated in order to lock housing assembly  16  to table assembly  14 . 
     Referring to FIG. 5, the present invention is directed towards table assembly  14  and locking mechanism  28  which locks table assembly  14  to base assembly  12  at any specified miter angle. Base assembly  12  defines a circular mounting structure  40  which includes a cylindrical cup shaped mounting boss  42  for mounting a table  44  as will be described later herein. Base assembly  12  also defines a plurality of threaded apertures  46  which are used to mount a detent plate  48  using a plurality of bolts  50 , only one being shown in FIG.  5 . Detent plate  48  defines a plurality of slots  52  which correspond to the plurality of threaded apertures  46  in order to allow for the securing of detent plate  48  to base assembly  12  by bolts  50 . The plurality of slots  52  permit adjustment of detent plate  48  to ensure the proper relationship of the pre-specified miter angles. Detent plate  48  further defines a plurality of detent slots  54  which are located at various popular miter angles for saw  10 . Detents  54  work in conjunction with locking mechanism  28  to locate table  44  at one of the various popular miter angles as will be described later herein. 
     Table assembly  14  includes table  44  and locking mechanism  28 . Table  44  is a circular plate-like member defining a work supporting surface  56  and a mounting boss  58 . Table  44  is rotatably mounted to base assembly  12  by inserting boss  58  of table  44  into boss  42  of base assembly  12 . A bolt  60  is inserted through table  44  and threadably received within a threaded bore (not shown) in base assembly  12  to complete the assembly. Bolt  60  is tightened enough to secure table  44  to base assembly  12  but it is not tightened to the point of restricting rotation of table  44  with respect to base assembly  12 . The threads on bolt  60  incorporate a patch lock to lock bolt  60  in position once it has been tightened. 
     Table  44  rotates with respect to base assembly  12  in order to change the miter angle of saw  10 . This rotation of table  44  changes the angular relationship of saw blade  18  with respect to fence assembly  26  but does not change the angular relationship of saw blade  18  with respect to table  44 . Disposed between table  44  and base assembly  12  are a plurality of wear plates  64 . Wear plates  64  provide a surface to support table  44  as well as reducing the friction and wear between table  44  and base assembly  12 . Wear plates  64  are preferably manufactured from spring steel and protect base assembly  12  which is preferably manufactured from aluminum from excessive wear that would cause excessive play between base assembly  12  and table  44  leading to cutting inaccuracy. 
     Referring now to FIGS. 5 and 6, lock assembly  28  comprises a miter locking mechanism  66 , a miter detent override mechanism  68  and a housing  70 . Housing  70  is a generally hollow rectangular member which is fixedly secured to table  44  such that it extends radially outward from table  44 . Housing  70  is positioned on table  44  such that when saw blade  18  is positioned perpendicular to fence  26 , or at a 0° miter angle, housing  70  is also generally perpendicular to fence assembly  26 . Thus, housing  70  is generally parallel to saw blade  18 . 
     Referring now to FIGS. 5-7, miter locking mechanism  66  comprises a locking lever  72 , a threaded locking rod  74  and a locking bracket  76 . Locking lever  72  is pivotably secured to the outer end of housing  70  by a pin  80 . The threaded end of locking rod  74  is threadingly received in a pivot pin  82  which is rotatably secured to locking lever  72 . Locking bracket  76  is fixedly secured to table  44  by a pair of bolts that extend through a pair of apertures  84  formed into locking bracket  76 . Locking bracket  76  defines a slot  86  which slidingly accepts locking rod  74 . Locking bracket  76  is a generally U-shaped component with one leg of the U defining slot  86  and the opposite end of the U defining a locking tab  88 . When locking bracket  76  is assembled to table  44  and table  44  is assembled to base assembly  12 , locking tab  88  is positioned adjacent to a cylindrical surface  90  located on base assembly  12 . 
     Miter locking mechanism  66  can be located in one of two positions by the pivotal movement of lever  72 . Referring now to FIG. 9C, miter locking mechanism  66  is shown in its locked position with lever  72  being located at a position angled downwardly from a horizontal position or a position angled downwardly from the upper surface of housing  70 . In this position, lever  72  urges locking rod  74  towards table  44  which in turn engages locking tab  88  against surface  90  of base assembly  12  locking table  44  with respect to base assembly  12  at the specifically desired miter angle. The load with which locking rod  74  engages locking tab  88  and surface  90  can be adjusted by rotating locking rod  74  within pivot pin  82  to adjust the working length of locking rod  74 . A screw driver slot is provided in the threaded end of locking rod  74  to facilitate this adjustment. A patch lock, or other retaining mechanism, is incorporated onto the threads of locking rod  74  to retain locking rod  74  at its desired location with respect to pivot pin  82 . 
     Referring now to FIG. 9D, miter locking mechanism  66  is shown in its released position with lever  72  being located at a generally horizontal position or at a position generally parallel with the upper surface of housing  70 . In this position, locking rod  74  is moved away from locking tab  88  and surface  90 . Table  44  can now be rotated with respect to base assembly  12  to be located at another desired miter angle. 
     Referring now to FIGS. 5,  6  and  8 , miter detent override mechanism  68  comprises a detent spring  92  and a detent override lever  94 . Detent spring  92  is secured to table  44  using a pair of bolts that extend through apertures  96  formed in detent spring  92 . Detent spring  92  is a generally U-shaped spring which includes a formed detent  98  on the connecting leg of the U. Detent spring  92  is normally positioned as shown in FIG. 9A with the shape of detent spring  92  being designed such that detent  98  biased into one of the detent slots  54  to releasably position support table  44  with respect to base assembly  12  at one of the more common miter angles defined by detent slots  54 . 
     Detent override lever  94  is pivotably secured to housing  70  using a clamp pivot  100  which is bolted to housing  70  using a pair of bolts extending through apertures  102  formed in clamp pivot  100 . The outer end of lever  94  extends towards locking lever  72  and is positioned between locking lever  72  and housing  70  as shown in FIGS. 5 and 6. The opposite of inner end of lever  94  extends toward detent spring  92 . The inner end of lever  94  is positioned under the outer end of detent spring  92  to enable lever  94  to move detent  98  out of engagement with the respective slot  54 . Detent spring  92  includes a pair of contoured tabs  104  which are cradled by the inner end of detent override lever  94 . A biasing spring  106  biases lever  94  in a clockwise direction, as shown in FIGS. 9A-9C, such that the inner end of lever  94  maintains engagement with contoured tabs  104 . 
     Detent override lever  94  is normally positioned as shown in FIG.  9 A. In this position, detent  98  is in engagement with one of the slots  54  to releasably hold table  44  at one of the more popular miter angles. When it is desired to reset support table  44  to a new miter angle, locking lever  72  of miter locking mechanism  66  is first moved to its released position as shown in FIG.  9 D and the outer end of lever  94  is pushed downward to pivot lever  94  in a clockwise direction as shown in FIG.  9 D. Support table  44  can now be rotated until the desired miter angle is reached. At this point, detent override lever  94  can be released causing detent  98  to engage another detent slot  54  if it is desired to select one of the more popular miter angles defined by detent slots  54 . Locking lever  72  of miter locking mechanism  66  is then moved to its locked position as shown in FIG. 9C to secure table  44  with respect to base assembly  12 . 
     When the desired miter angle is not one of the pre-selected miter angles defined by slots  54 , the adjustment of table  44  is similar but different to that described above. With table  44  locked to base assembly  12  as shown in FIG. 9C, when it is desired to reset support table  44  to a new miter angle, locking lever  72  of miter locking mechanism  66  is first moved to its released position as shown in FIG. 9A or  9 B and the outer end of lever  94  is pushed downward to pivot lever  94  in a clockwise direction as shown in FIG.  9 D. This clockwise rotation of lever  94  causes the inner end of lever  94  to lift detent spring  92  causing the disengagement of detent  98  with its respective slot as shown in FIG.  9 D. When the desired miter angle is reached, locking lever  72  of miter locking mechanism  66  is moved to its locked position as shown in FIG. 9C to secure table  44  with respect to base assembly  12 . Once locking lever  72  has been locked, lever  94  can be released. The release of lever  94  allows detent spring  92  to engage the upper surface of detent plate  48  as shown in FIG. 9B because detent  98  is not aligned with one of slots  54 . By keeping pressure on miter detent override lever  94  while engaging locking lever  72 , detent  98  is kept away from detent plate  48  and slots  54 . This allows the setting of a miter angle near one of the slots  54  (i.e., 44° instead of 45°) without having the biasing load of detent spring  92  reacting against detent plate  48  to urge table  44  to the desired angle. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.