Patent Document

This Application is a division of Ser. No. 08/923,573 filed Sep. 4, 1997 now U.S. Pat. No. 5,957,022, which is a continuation of Ser. No. 08/9 18,700 filed Aug. 21, 1997, now U.S. Pat. No. 5,943,931, which is a divisional of Ser. No. 08/499,339 filed Jul. 7, 1995 now U.S. Pat. No. 5,755,148. 
    
    
     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 an adjustable fence assembly for such power operated equipment, with the fence assembly having a fixed fence and a pair of movable fences for selectively adjusting the gap between the cutter and the movable fences in order to allow sufficient clearance for performing various operations on a workpiece when the equipment is in any of a number of different cutting or working modes. 
     BACKGROUND OF THE INVENTION 
     Saws and other apparatuses designed for cutting or performing other working operations on a workpiece typically require a workpiece-supporting fence in order to support and locate the workpiece in a proper fixed position for performing the working operation. 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 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 other materials. 
     In order to accommodate these widely varied working operations, the workpiece-supporting fence is frequently required to be at least partially adjustable in order to selectively vary the gap or space between the saw blade or cutter and the workpiece-supporting fence, thus selectively providing clearance for the saw blade, cutter, or other device performing the working operation on the workpiece. If such adjustability were not available, a relatively large permanent gap would have to be provided between the fixed fence and the saw blade or cutter in order to accommodate the widely varying range of movement, position, or size of the saw blade, cutter, or other working device. 
     In order to address the above-discussed problems associated with providing clearance for the cutter and support for the workpiece with the incorporation of a movable fence having an adjustable clearance gap, a variety of fence-adjusting arrangements have previously been provided. However, many of such prior fence-adjusting arrangements have suffered various disadvantages, including difficulty in maintaining proper alignment between the stationary fence and the movable fence in wide-gap positions, inconvenience in performing fence adjustment operations, the possibility of inadvertently misplacing a removable fence, lack of adequate support for relatively tall or thick workpieces, or other similar disadvantages. Thus, the need has arisen for an adjustable fence assembly for compound miter saws, or other power equipment requiring fence adjustability, which overcomes these disadvantages, as well as providing improved ease of operation, economy in manufacturing, and other advantages that will become readily apparent to those skilled in the art from the discussion below. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, an improved adjustable workpiece-supporting fence assembly includes a pair of movable fences laterally movably interconnected with a fixed fence which is secured to a base of the device in which it is employed. The pair of movable fences are disposed on opposite sides of a saw blade, a workpiece cutter or other such device for performing a working operation on a workpiece. Each movable fence is independently movable, and is selectively and laterally movably interconnected with the fixed fence on opposite sides of the workperforming blade or cutter. Each is also laterally spaced from the other movable fence located on the opposite side of the blade or cutter. The base or other portion of the device in one preferred form of the invention supports the fixed fence having a fence guide fixedly disposed on opposite sides of the blade or cutter with a laterally-extending slot formed in each of the fence guides. The laterally-extending slots which preferably have spaced opposite internal walls therein are adapted to receive a laterally extending tongue portion on a respective one of the pair of movable fences. The tongue is slidably received within the respective slot for selective adjustable lateral movement of the movable fences toward and away from the blade or cutter. 
     In the above described preferred embodiment of the present invention, a single fixed clamping arrangement is interconnected with the fixed fence on each side of the saw blade or cutter. Each single fixed clamping arrangement releasably and clampingly urges the tongue on the respective movable fence against the front wall of the laterally-extending slot at any of a number of adjusted positions therein. 
     In one preferred embodiment of the present invention, the single fixed clamping arrangement includes a threaded clamping member disposed on each outside end (end farthest away from the cutter) of the fixed fence and a locating pad machined into the slot of each fence guide. The locating pads are formed on each side of the saw blade or cutter at the inside end (end closest to the saw blade or cutter) of the fence guide. A corresponding locating surface is formed on the tongue of each movable fence such that the locating surface on the movable fence engages the locating pad on the fence guide when the movable fence is located at its innermost position. The locating pad and locating surface are machined to tight tolerances, thus allowing the utilization of a single threaded clamping member disposed at the outside end of the fixed fence. When the movable fence is moved towards its outermost position, the locating pad disengages from the locating surface at approximately the same time the center of the movable fence is positioned in line with the threaded clamping member thus allowing the utilization of a single threaded clamping member disposed at the outside end of the fence guide. 
     In an additional preferred embodiment of the present invention, the single fixed clamping arrangement includes a longitudinally extending clamping rod positioned generally parallel to each slot. The clamping rod incorporates a continuous locking lobe or a plurality of locking lobes such that rotation of the clamping rod causes the locking lobe or lobes to clamp the movable fence against the front wall of the slot in the respective fence guide. 
     In addition, the preferred embodiments of the present invention also include a gap-filling flap pivotably mounted to the inside end of each movable fence. Each gap-filing flap in its lower position is designed to provide additional support for the workpiece at a position immediately adjacent to the saw blade or cutter. 
     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 
     In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
     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 a perspective view of the adjustable fence assembly in accordance with the present invention illustrating one side of the adjustable fence assembly exploded and the other side in the assembled condition; 
     FIG. 6 is a schematic plan view diagram of the sliding compound miter saw of FIGS. 1 through 4 schematically illustrating the position of the saw blade relative to the adjustable fence in a miter cutting position and a straight cross cut position; 
     FIG. 7 is a schematic diagram, similar to that of FIG. 6, but shown in an elevational view and illustrating the adjustable fence assembly shown in a bevel cutting condition and a straight cut position; 
     FIG. 8A is a partial cross-sectional view of the adjustable fence assembly illustrating the single locking mechanism and an anti-removal system according to the present invention; 
     FIG. 8B is a view similar to  8 a but showing an anti-removal system according to another embodiment of the present invention; 
     FIG. 9 is a schematic front perspective view of the adjustable fence assembly shown prior to the saw blade or cutter providing the minimum allowable clearance between the two gap-filling flaps; 
     FIG. 10 is a front elevational view, partially in cross section, of one of the fence guides of the adjustable fence assembly illustrating the fixed fence pad according to the present invention; 
     FIG. 11 is an enlarged plan view, partially in cross-section, of the engagement between the fixed fence pad and the movable fence according to the present invention; 
     FIG. 12 is a schematic diagram, looking from the rear of the saw, depicting the fully retracted and partially extended positions of the movable fences; 
     FIG. 13 is a schematic diagram similar to FIG. 7 illustrating a single locking mechanism according to another embodiment of the present invention; 
     FIG. 14 is a front elevational view of the cam locking bar shown in FIG. 13; 
     FIG. 15 is a cross-sectional view illustrating the shape of the cam locking bar shown in FIGS. 13 and 14; 
     FIG. 16 is a partial cross-sectional view similar to FIG. 8 a  but illustrating the single locking mechanism shown in FIG. 13; 
     FIG. 17 is a front elevational view of a cam locking bar according to another embodiment of the present invention; 
     FIG. 18 is a cross-sectional view illustrating the shape of the cam locking bar shown in FIG. 16; 
     FIG. 19 is a schematic front perspective view similar to FIG. 5 of the adjustable fence according to another embodiment of the present invention; 
     FIG. 20 is a schematic illustration of an interfering relationship of the saw blade guard with the movable fence of the work-supporting fence assembly for alerting the operator that the movable fence of the fence assembly has not been properly adjusted for the operation being performed; 
     FIG. 21A is a front elevational view of an adjustable fence assembly incorporating a fence position indicator in accordance with the present invention; 
     FIG. 21B is a view similar to FIG. 21 a  but showing the fence assembly of the present invention adjusted for a 30° bevel cut; 
     FIG. 21C is a view similar to FIG. 21 a  but showing the fence assembly of the present invention adjusted for a 45° miter cut; and 
     FIG. 21D is a view similar to FIG. 21 a  but showing the fence assembly of the present invention adjusted for a compound miter cut of a 30° bevel cut and a 45° miter cut. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     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 12 an exemplary sliding compound miter saw incorporating an adjustable fence assembly 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 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 adjustable fence 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 selective adjustment of the gap or spacing in the fence assembly in order to accommodate different sizes or positions of tooling, or to perform various different workpiece working operations. 
     Referring primarily to FIGS. 1 through 4, sliding compound miter saw  10  includes a base assembly  12 , including a table assembly  14 , which is preferably rotatable in order to accommodate the various cutting positions discussed below. Miter saw  10  also includes a saw blade  16 , a blade guard  18 , a motor  20  drivingly connected to saw blade  16 , and a handle  22 . Handle  22  assists the operator in moving saw blade  16  and blade guard  18  from a clear position free of a workpiece  24  to a cutting position with saw blade  16  in cutting engagement with workpiece  24 . 
     A fence assembly, as best seen in FIGS. 1 through 5 and indicated generally by the reference numeral  30 , is interconnected with base  12  and extends laterally across table assembly  14 , against which workpiece  24  is positioned and supported for performing a cutting operation thereon. According to the present invention, fence assembly  30  includes a first and a second movable fence  32  and  34 , respectively, extending in a mutually aligned lateral direction, with each movable fence  32  and  34  being laterally spaced from the other. Such lateral spacing or gap between the two movable fences  32  and  34 , provides clearance for saw blade  16  to perform a cutting operation completely through workpiece  24 , regardless of the mode or type of cutting operation being performed. As is discussed in more detail below, movable fences  32  and  34  are each movable toward and away from saw blade  16  in order to allow the operator to selectively adjust the clearance gap therebetween and thus accommodate the particular cutting operation being performed. 
     As is schematically illustrated in FIGS. 6 and 7, the exemplary sliding compound miter saw  10  depicted in the drawings is capable of a number of different cutting modes or positions. In FIG. 6, a schematic plan view generally illustrates the position of saw blade  16  relative to base assembly  12  and fence assembly  30  when performing a straight sliding or straight miter-cutting operation. Such straight, square, sliding cutting operations are schematically illustrated by the position of saw blade  16  shown in solid lines in FIG.  6 . The movable fences  32  and  34  are selectively adjusted to provide the minimum required clearance gap between saw blade  16  and the two movable fences  32  and  34 , to permit saw blade  16  to be moved into the cutting position along a single, vertical plane, substantially perpendicular to both the front face of fence assembly  30  and the upper face of table assembly  14 . To permit miter cutting, as schematically illustrated in phantom lines in FIG. 6, movable fence  32  is preselectively adjusted, as indicated in phantom by reference numeral  32   a , to increase the clearance gap between saw blade  16  and movable fence  32   a , in order to provide sufficient clearance for saw blade  16   a  and the associated components. 
     FIG. 7 illustrates saw blade  16  and fence assembly  30  in a schematic elevational view, showing the position of saw blade  16  and movable fences  32  and  34  as solid lines for performing the above-described straight, square, sliding operation. The relative positions of saw blade  16  and movable fence  32  are shown in phantom lines, as indicated by reference numeral  16   b  and  32   b , respectively, for performing bevel cuts on workpiece  24 . The plane of movement of saw blade  16   b  is generally perpendicular to the face of fence assembly  30 , but can be selectively oriented at a bevel angle with respect to table assembly  14 . Again, fence  32  can be adjusted to a predetermined position, as shown in phantom at  32   b , to accommodate the bevel angle selected for saw blade  16   b.    
     Although not specifically illustrated in the drawings, one skilled in the art will readily recognize, from the exemplary positions diagrammatically illustrated in FIGS. 6 and 7, that the miter-cutting operation can be combined with the bevel-cutting operation in order to perform compound mitering. In a compound mitered cut, saw blade  16  moves in a plane which is not perpendicular either to the front face of fence assembly  30  or to the upper face of table assembly  14 . In addition, although not specifically illustrated in the drawings, one skilled in the art will readily recognize, from the exemplary positions diagrammatically illustrated in FIGS. 6 and 7, that the miter-cutting operation and the bevel-cutting operation can be performed by angling saw blade  16  in the opposite direction from what is illustrated and then selectively adjusting movable fence  34  (but to the right in FIGS. 6 and 7) in a manner similar to that shown for movable fence  32 . 
     Thus, sliding compound miter saw  10  shown for purposes of illustration in the drawings is capable of at least four general types of cutting operations, to which reference is made herein as sliding, miter-cutting, bevel-cutting and compound miter-cutting operations. The miter-cutting, bevel-cutting and compound miter-cutting operations can be performed by angling saw blade  16  in either direction from the sliding operation due to the incorporation of movable fences  32  and  34  on opposite sides of saw blade  16 . Literally, an infinite compound adjustability of the relative position and orientation of saw blade  16  relative to both table assembly  14  and fence assembly  30  can be accomplished in the present invention by way of a compound pivot and slide mounting mechanism referred to generally as reference numeral  40  in FIGS. 1,  3  and  4 . Compound pivot and slide mounting mechanism  40  can be any of a number of well-known pivot and bevel mounting and support mechanisms which also allow saw blade  16  and blade guard  18  to be pivotally and slidingly moved from a rear, raised, clear position to a lowered or cutting position, once miter saw  10  is adjusted to the desired operating mode, in order to perform a cutting operation on workpiece  24  by lowering saw blade  16  into workpiece  24  and then moving saw blade  16  longitudinally through workpiece  24 . 
     In order to allow a complete cut-through operation to be performed on workpiece  24  by saw blade  16 , fence assembly  30  must be capable of selective adjustment in order to preadjust the lateral clearance gap or spacing between saw blade  16  and the two movable fences  32  and  34 , while still providing adequate vertical support for workpiece  24 . In accordance with a preferred form of the present invention as best shown in FIG. 5, the adjustability of fence assembly  30  is accomplished in part by securing a fence-supporting member  42  to base assembly  12 . Fence-supporting member  42 , as shown in FIGS. 5 and 8A, is a separate component fixedly secured to base assembly  12  by a plurality of bolts  44 , and includes an interconnecting portion  46  extending laterally across a clearance gap, behind movable fences  32  and  34  to interconnect a pair of fixed fences  48  and  50 , as shown in FIGS. 1,  3  and  5 , without interfering with the complete cutting of a workpiece  24 . Fence-supporting member  42  is fixedly secured to, or interconnected with, base assembly  12  with its fixed fences  48  and  50  being mutually aligned in a laterally-extending direction. 
     As seen in FIGS. 8A through 12, fixed fences  48  and  50  of fence-supporting member  42  preferably include a slot  52  defined by a first or front internal wall  54  spaced away from a second or rear internal wall  56 , in order to form a space therebetween extending laterally along both fixed fences  48  and  50  on opposite sides of saw blade  16 . Each movable fence  32  and  34  preferably includes an upper portion  58 , an optional spring biased gap-filing flap  60 , and a tongue portion  62  slidingly received within a respective slot  52 , with the lower face  107  of each upper portion  58  slidingly engaging fence-supporting member  42 . The front external faces  63  of fence-supporting member  42  and front faces  67  of each movable fence  32  and  34 , respectively, are vertically aligned and flush with one another as illustrated in FIG.  8 A. 
     Prior to performing a cutting operation on workpiece  24 , the minimum clearance between gap-filling flaps  60  must first be set. This procedure begins, as shown in FIG. 9, with each movable fence  32  and  34  being secured at its innermost position with a stop  61  on each movable fence  32  and  34  engaging a stop  64  located on each fixed fence  48  and  50  (see also FIG.  5 ). In this position, both gap-filling flaps  60  are biased by a spring (not shown) to their lowered position eliminating the gap between movable fences  32  and  34 . Miter saw  10  is placed in its straight sliding position and saw blade  16  is moved to cut through gap-filling flaps  60 , which are manufactured from easily cutable material, such as ABS, nylon or any other rigid plastic to provide the minimum clearance for movable fences  32  and  34 . Flaps  60  could also be made form a non-ferous material such as aluminum if clearance for saw blade  20  is provided in the initial design of these flaps. 
     In order to selectively secure each movable fence  32  and  34  in a preselected, adjusted position for purposes of performing a desired cutting operation, a single fixed clamping arrangement  66  is preferably provided for releasably fixing the position of each movable fence  32  and  34  relative to its respective fixed fence  48  or  50 , with their front faces  67 ,  63 , respectively, being flush and vertically aligned. Single fixed clamping mechanism  66  will be described in relation to movable fence  32  and fixed fence  48 . It is to be understood that an identical clamping mechanism  66  can be associated with movable fence  34  and fixed fence  50  of the present invention. Single fixed clamping mechanism  66  preferably includes a clamping screw  68  threadably engaging and movable within a threaded opening  70  in fixed fence  48 . Clamping screw  68  is selectively rotatable by way of a manual knob  72  in order to threadably advance clamping screw  68  toward tongue portion  62  and to clampingly and forcibly urge tongue portion  62  against front internal wall  54  of slot  52  as shown in FIG.  8 A. Single fixed clamping mechanism  66  properly positions movable fence  32  due to the incorporation of an integrally machined pad  74  located on fixed fence  48  and a corresponding integrally machined surface  76  located on movable fence  32  as best illustrated in FIGS. 5,  8 A,  10  and  11 . Machined pad  74  is located on the innermost end of fixed fence  48  within slot  52  and in the preferred embodiment extends a distance of approximately 1.20 inches. Machined surface  76  extends along the entire inside length of movable fence  32 , although it is within the scope of the present invention to provide a smaller machined surface  76  which would be located on the inside end of movable fence  32 . This smaller machined surface  76  would be similar to and designed to mate with machined pad  74 . Thus, when movable fence  32  is moved to its innermost position, as shown in solid lines of FIG. 12, machined pad  74  engages machined surface  76 , as shown in FIG. 11, in order to insure that the front face  67  of movable fence  32  is vertically aligned and flush with the front external face  63  of fixed fence  48 . Machined pad  74  and machined surface  76  are machined to a tight tolerance in order to reduce the amount of clearance between the pad  74  and surface  76  to approximately 0.006 inches ±0.002 inches when they are engaged. Thus, the clearance between tongue portion  62  of movable fence  32  and slot  52  of fixed fence  48  is reduced to approximately 0.006 inches which eliminates the need to incorporate a clamping member in the area adjacent the innermost portion of movable fence  32 . The small clearance between machined pad  74  and machined surface  76  prohibits the rearward movement of movable fence  32  thus keeping faces  63  and  67  flush and vertically aligned. As shown in FIGS. 8A and 8B, movable fence  32  is clamped in position by rotating knob  72  which threadably advances clamping screw  68  toward tongue portion  62  to clampingly and forcibly urge tongue portion  62  against front internal wall  54  of slot  52 . The opposite end of movable fence  32  is held in position by the engagement of machined pad  74  and machined surface  76  as detailed above. 
     The engagement between machined pad  74  of fixed fence  48  and machined surface  76  of movable fence  32  will continue as movable fence  32  is moved outwards until the proximate center of movable fence  32  generally aligns with the center line of clamping screw  68 . At this point in the adjustment of movable fence  32  and throughout the remainder of the outward adjustment of movable fence  32 , the single fixed clamping mechanism incorporating clamping screw  68  provides sufficient clamping without the engagement of pad  74  and surface  76  due to the now centralized location of clamping screw  68  to position movable fence  32  flush and vertically aligned with fixed fence  48  as illustrated in FIG.  8 A. 
     In order to minimize the possibility of inadvertent removal of movable fence  32  from fixed fence  48  during position adjustments, machined surface  76  of tongue portion  62  is preferably provided with an elongated anti-removal groove or slot  78  extending laterally therealong, as shown in FIGS. 5 and 8A. Anti-removal slot  78  in movable fence  32  is aligned with a clamping plate  79  which is fixedly secured to fixed fence  48  by a plurality of bolts  81 . Clamping plate  79  extends into slot  78  to prevent vertical removal of movable fence  32 . Removal of movable fence  32  can be accomplished by the lateral movement of movable fence  32  until the movable fence is totally removed. Clamping plate  79  also resists the upward movement of movable fence  32  due to the reaction of spring loaded gap-filling flap  60 . 
     Thus, when adjustment of movable fence  32  is required, clamping screw  68  is loosened to the point of releasing the clamping load on movable fence  32 . This allows for the lateral adjustment of movable fence  32  without inadvertent removal of movable fence  32  from slot  52 . When it is desired to remove movable fence  32  for repair, replacement or cleaning, however, clamping screw  68  (see FIG. 8A) is loosened allowing removal of movable fence  32  by moving movable fence  32  laterally to disengage clamping plate  79  from slot  78 . 
     As indicated above, movable fence  34  and fixed fence  50  also incorporate single fixed clamping arrangement  66  in order to secure movable fence  34  to fixed fence  50  on the opposite side of saw blade  16 . 
     Also as noted above, each movable fence  32  and  34  is provided with a respective spring biased gap-filling flap  60 . The location and function of gap-filling flap  60  will be described in relation to movable fence  32  and fixed fence  48 . It is to be understood that an identical gap-filling flap  60  is associated with movable fence  34  and fixed fence  50  on the opposite side of saw blade  16  in the present invention. Flap  60  is pivotably mounted at  81  to movable fence  32  within a recess  80  provided at the inner end of movable fence  32 . Gap-filling flap  60  is biased to its lower position, as shown in FIG. 5 in solid lines, by a spring (not shown). As described above in reference to FIG. 9, when gap-filling flap  60  is located in its lowered position, the minimum gap between movable fence  32  and saw blade  16  is initially provided. As shown in FIGS. 8A and 9, flap  60  is provided with a tab  82  which rides in a slot  84  longitudinally extending along fixed fence  48  generally parallel to slot  52 . The width of flap  60 , the depth of recess  80 , the location and thickness of tab  82  and the thickness and width of slot  84  are selected to position the outer surface of flap  60  in a vertically aligned generally flush location with faces  63  of fixed fence  48  and faces  67  of movable fence  32 . Flap  60  can be moved from its lowered position, as shown in FIG. 9, due to the engagement of a ramped or angular surface  86  located on fixed fence  48  with a corresponding angular surface  88  located on flap  60 . As movable fence  32  is moved laterally from its innermost position toward its outermost position, surfaces  86  and  88  react to pivot flap  60  upwardly, as shown in phantom in FIG.  12 . 
     When movable fences  32  and  34  are located in their innermost positions, as shown in FIG. 9, movable flaps  60  are restricted from pivoting due to the engagement of tabs  82  with blind ends  90  of slots  84 . The movement of movable fences  32  and  34  laterally towards their outermost positions disengages tabs  82  from their respective blind end  90  allowing for the pivoting of gap-filling flaps  60 . 
     As indicated above, movable fence  34  also incorporates a respective gap-filling flap  60  in order to minimize the gap between movable fence  34  and saw blade  16 . The above description applies equally well to movable fence  34  and fixed fence  50 . 
     FIGS. 13 through 16 illustrate another embodiment of a single fixed clamping arrangement  100  for releasably fixing the position of each movable fence  32  and  34  relative to its respective fixed fence  48  and  50 , with their respective front faces  67  and  63  flush and vertically aligned. Single fixed clamping mechanism  100  will be described in relation to movable fence  32  and fixed fence  48 . It is to be understood that an identical fixed clamping mechanism  100  may be associated with movable fence  34  and fixed fence  50  of the present invention. Single fixed clamping arrangement  100  preferably includes a locking cam rod  102  rotatably connected to fixed fence  48  as shown in FIG.  13 . Locking cam rod  102 , as shown in FIGS. 14 and 15, includes a longitudinally extending shaft  104  having a plurality of cam lobes  106  disposed along its length. The end of shaft  104  which extends beyond the outside of fixed fence  48  is bent at an approximately 90° angle to provide an actuation handle  108  for mechanism  100 . Cam rod  102  is disposed between rear internal wall  56  of slot  52  and tongue portion  62  of movable fence  32  as shown in FIG.  16 . When cam lobes  106  are located in a generally vertical position, movable fence  32  may slide relative to fixed fence  48  because there is no engagement with cam rod  102 . When cam rod  102  is rotated approximately 90°, cam lobes  106  move from a vertical position to a horizontal position. During this movement from a vertical position to the horizontal position, cam lobes  106  cammingly engage an angular surface or ramp  110  located on tongue portion  62  to clamp the lower face  107  of upper portion  58  of movable fence  32  against fence-supporting member  42  and the front face  109  of tongue portion  62  against front internal wall  54  of fixed fence  48  thus securing movable fence  32 . The height of cam lobes  106  is selected to be greater than the gap between tongue portion  62  and fixed fence  48 , thus producing the required clamping load. The number of cam lobes  106  which engage movable fence  32  will depend upon the relative lateral positioning of movable fence  32  along fixed fence  48 . 
     As indicated above, movable fence  34  and fixed fence  50  can also incorporate single fixed clamping arrangement  100  in order to secure movable fence  34  to fixed fence  50  on the opposite side of saw blade  16 . The above description applies equally well to movable fence  34  and fixed fence  50 . 
     FIGS. 17 and 18 illustrate another preferred embodiment for a locking cam rod  112 . Locking cam rod  112  is rotatably secured to each fixed fence  48  and  50  in a similar manner to locking cam rod  102 . The difference between locking cam rod  112  and locking cam rod  102  is that locking cam rod  112  includes a longitudinally extending shaft  114  having a continuously extending cam lobe  116  disposed along its entire length. The remainder of locking cam rod  112  and the operation of locking cam rod  112  is the same as that described above for locking cam rod  102 . The length of cam lobe  116  which engages movable fences  32  and  34  will depend upon the lateral positioning of movable fences  32  and  34  along their respective fixed fences  48  and  50 . 
     FIG. 19 illustrates a fence assembly  130  according to another embodiment of the present invention. Fence assembly  130  is similar to fence assembly  30  but it does not include pivotable flaps  60 . In place of flaps  60 , fence assembly  130  includes a pair of movable fences  132  and  134  incorporating a raised portion  136 . Here, a raised portion  136  is formed generally at the saw blade end of movable fences  132  and  134 , with the edge of each raised portion  136  sloping generally downward toward saw blade  16  and table assembly  14 . Such raised portions  136  are sized and configured, as is schematically illustrated in FIG. 20, so that it interferingly engages blade guard  18  if blade guard  18  and saw blade  16  are moved from their rear clear positions to their cutting position when in substantially all of the cutting set-up modes or configurations of which sliding compound miter saw  10  is capable. 
     In addition, as can be seen in FIG. 19, raised portions  136  of movable fences  132  and  134  provide an increased vertical workpiece supporting face or surface, which allows the operator to properly support a relatively tall or thick workpiece. Such increased-height workpiece-supporting capability is especially advantageous when cutting thick stock, crown moldings, base boards, or other such relatively tall workpiece shapes, orientations or configurations. Single fixed clamping arrangement  66  or single fixed clamping arrangement  100  can be utilized with movable fences  132  and  134  in a similar manner as that described above for movable fences  32  and  34  in order to laterally secure movable fences  132  and  134  in their selected positions. 
     In order to minimize the possibility of inadvertent removal of movable fence  132  from fixed fence  48  or movable fence  134  from fixed fence  50  during position adjustments, the rear face  176  of tongue portion  162  is preferably provided with an elongated anti-removal groove or slot  178  extending laterally therealong, as shown in FIGS. 8B and 20. Anti-removal slot  178  in movable fence  132  is aligned with clamping screw  68  such that clamping screw  68  extends into slot  178  prior to exerting any clamping load on movable fence  132 . 
     Thus, when adjustment of movable fence  132  is required, clamping screw  68  is loosened to the point of releasing the clamping load on movable fence  132  but still in engagement with slot  178 . This allows for the lateral adjustment of movable fence  132  without inadvertent removal of movable fence  132  from slot  52 . As seen in FIG. 20, the lateral length of slot  178  is sufficient to allow full adjustment of movable fence  132  but insufficient to allow inadvertent lateral removal of movable fence  132 . When it is desired to remove movable fence  132  for repair, replacement or cleaning, however, clamping screw  68  (see FIGS. 8 b  and  19 ) is loosened allowing removal of movable fence  132 . As indicated above, movable fence  134  and fixed fence  50  also incorporate anti-removal slot  178  for engagement with clamping screw  68 . 
     FIGS. 21 a  through  21   d  schematically illustrate a fence position indicator  150  associated with fence assembly  30 , although it is within the scope of the present invention to incorporate fence position indicator  150  into fence assembly  130  or any other type of movable fence assembly. 
     Fence position indicator  150  includes an upper indicator  152  secured to movable fences  32  and  34  and a lower indicator  154  secured to fixed fences  48  and  50 . Upper fence indicator  152  has positions marked to indicate the degree of bevel angle to which sliding compound miter saw  10  is to be or has been adjusted. Lower fence indicator  154  has positions marked to indicate the degree of miter angle to which miter saw  10  is to be or has been adjusted. Thus, by aligning the proper beveling mark on upper fence indicator  152  with the proper mitering mark on lower fence indicator  154 , the proper fence position for movable fences  32  and  34  will be achieved. Fence position indicator  150  can also be incorporated with movable fences  132  and  134  if desired. 
     For example, for making solely a bevel cut of 30°, as shown in FIG. 21 b , the 30° mark on upper indicator  152  is aligned with the 0° mark on lower indicator  154 . For making solely a miter cut of 45°, as shown in FIG. 21 c , the 45° mark on lower indicator  154  is aligned with the 0° mark on upper indicator  152 . For a compound cutting operation for a bevel cut of 30° in combination with a miter cut of 45°, as shown in FIG. 21 d , the 30° mark on upper indicator  152  is aligned with the 45° on lower indicator  154 . 
     It may be advantageous to include a mechanism for releasably holding movable fences  32  and  34  when movable fences  32  and  34  are located in one or more of the most popular beveling and/or mitering positions. This can be accomplished by providing movable fences  32  and  34  with one or more indentations  170  extending along the front face of tongue  62 , as shown in FIG.  5 . Then by incorporating a spring loaded check ball assembly  172 , as shown in FIG. 8A, positioned in fixed fences  48  and  50  at the proper locations, movable fences  32  and  34  will be releasably held at the various positions of movable fences  32  and  34 . 
     While the present invention has been described for exemplary purposes as being incorporated into sliding compound miter saw  10 , it is within the scope of the present invention to incorporate the movable fence assemblies of the present invention into compound miter saws, chop saws, radial arm saws, table saws, dado saws, spindle shapers, sanders or other types of powered or unpowered devices that could benefit from the selective adjustment of the distance between the fence and the working tool. 
     While the above detailed description describes the preferred embodiment of the present invention, it should be understood that the present invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims.

Technology Category: b