Abstract:
A depth of cut scale is provided for a circular saw having a foot, a pivoting assembly (including a rotary saw blade) pivotably mounted to the foot, and a depth of cut adjustment mechanism operable to lock the pivoting assembly at a depth of cut (DOC) orientation relative to the foot. The depth of cut scale includes a shelf associated with and pivotable with the pivoting assembly. The shelf includes an upper surface bearing indicia indicative of DOC. An elongated element is fixed at one end relative to the pivoting assembly and includes a pointer adjacent an opposite end arranged to point to the indicia on the upper surface. The pointer is fixed in relation to the shelf as the shelf pivots with the pivoting assembly. The elongated element may be a flexible element that is maintained in tension overlaying the upper surface, or a cantilevered arm.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to portable circular saws, and particularly to a display for indicating a saw&#39;s cutting depth. 
         [0002]    Circular saws are typically provided with the capability of adjusting the depth of cut (DOC) relative to the workpiece. In using a circular saw, it is desirable from a cutting performance standpoint that the cutting blade extends a predetermined distance below the surface of the workpiece being cut. That predetermined distance is typically one tooth depth to avoid splintering as the cut is made. 
         [0003]    In a typical circular saw  10 , depicted in  FIG. 1 , a pivoting assembly  11  includes a motor housing  12  with a hand grip for guiding the saw during a cut. The motor housing and hand grip are mounted to an upper guard  16  that shrouds the upper portion of the cutting blade  18 . The upper guard of the pivoting assembly  11  is pivotably mounted to a foot  20  at a pivot mount  17  ( FIG. 2 ). The foot  20  is planar and adapted for sliding along the workpiece during a cut. The foot  20  defines a slot  22  ( FIG. 1 ) through which the cutting blade extends. 
         [0004]    The upper guard  16  is pivotably mounted to the foot  20  to allow the entire assembly of the motor, guard and cutting blade to pivot in the direction P ( FIG. 2 ) relative to or away from the foot  20 . In an initial position, as depicted in  FIGS. 1-2 , the cutting blade extends at its maximum DOC As the pivoting assembly  11  is pivoted upward in the direction P, the DOC is decreased. 
         [0005]    The circular saw  10  incorporates a mechanism for permitting adjustment of the DOC and fixing the cutting blade at the particular pivot angle corresponding to that DOC. Thus, in certain saws, a DOC bracket  24  ( FIG. 1 ) projects perpendicularly upward from the back edge of the foot  20  and generally parallel with the upper guard  16 . An adjustment rod  26  extends from the upper guard  16  (and/or the hand grip  14 ) and through a slot  25  in the bracket  24 . An adjustment lever  28  may be provided to manually loosen or tighten the rod relative to the bracket  24  in a known manner. When the lever  28  is released or manipulated to release the clamping force between the rod  26  and the DOC bracket  24 , the pivoting assembly  11  can be pivoted in the direction P, after which the lever  28  can be returned to its locking position to fix the pivoting assembly at a desired orientation. 
         [0006]    In order to determine the actual DOC of the cutting blade, a scale  30  is provided on the upper guard  16 . A tab  32  projecting from the depth adjustment bracket  24  points to a particular depth value on the scale. As can be seen from  FIGS. 1-2 , the scale  30  and tab  32  are best viewed from one end of the saw  10 . Moreover, due to the orientation of the scale the user must typically bend down to achieve a more horizontal line of sight in order to accurately read the DOC value. At a minimum, requiring the user to bend down in order to read the DOC value is uncomfortable to the user. In the worst case, the user cannot bend to the optimal line of sight and thus misreads the DOC value. There is therefore a need for a DOC scale that can be accurately read without requiring any physical gyrations by the user. 
       SUMMARY 
       [0007]    In accordance with one feature, a depth of cut scale is carried by the upper guard of a circular saw in a location that can be viewed from above the saw. A circular saw includes a foot, a pivoting assembly (including the rotary saw blade) pivotably mounted to the foot, and a depth of cut (DOC) adjustment mechanism operable to lock the assembly at a particular pivot angle relative to the foot. The line of sight depth of cut scale includes a shelf associated with and pivotable with the assembly, the shelf including an upper surface bearing indicia indicative of DOC. The scale further includes an elongated element fixed at one end relative to the pivoting assembly and arranged to overlay the upper surface. The elongated element includes a pointer arranged to point to the indicia. The pointer has a fixed spatial relationship relative to the shelf as the shelf pivots with the pivoting assembly, so that the pointer and shelf in effect move relative to each other. 
         [0008]    In one embodiment, the elongated element is an elongated flexible element that is connected to the pivoting assembly at an end opposite the fixed end. In a further feature, the depth of cut scale includes a tension mechanism mounted to the pivoting assembly and connected to the opposite end of the flexible element. The tension mechanism is operable to maintain the flexible element in tension as the pivoting assembly pivots relative to the foot. The tension mechanism may include a spring, and in particular a coil or torsion spring, contained within a housing mounted to the assembly. 
         [0009]    In another aspect, the flexible element is a flexible strip. The flexible strip has a width less than the width of the shelf upper surface and is arranged relative to the upper surface to not overlap the indicia. In an alternative embodiment, the flexible strip is configured so that the indicia are visible through the strip when said strip overlays the upper surface. Where the DOC adjustment mechanism includes a depth adjustment bracket mounted to the foot, one end of the flexible element is connected to the bracket. 
         [0010]    In another embodiment, the elongated element is an arm that is cantilevered at the one end fixed relative to the pivoting assembly. The arm may incorporate a collar that is pivotably mounted to the depth adjustment bracket by a nut and bolt, or other suitable means (such as a shoulder rivet or screw). In a further feature, the pivot mount for the arm may include a biasing element operable to generate a torque to bias the arm toward the upper surface of the shelf. The arm includes the pointer adjacent the opposite end, which may be a visual symbol, such as an arrow, or may include a notch through which a DOC indicia is visible. The arm may be arranged to overlie at least a portion of the upper surface of the shelf. 
         [0011]    In another aspect, the arm is situated beneath the shelf and the notch is configured to receive an edge of the shelf therein. An upper branch of the notch forms the pointer and travels along the upper surface of the shelf as the shelf pivots with the pivoting assembly. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0012]      FIG. 1  is a top perspective view of one type of circular saw. 
           [0013]      FIG. 2  is a side perspective view of a circular saw of the type shown in  FIG. 1 , modified in accordance with the present disclosure, viewed with certain components of the saw removed for clarity. 
           [0014]      FIG. 3  is a top perspective view of a circular saw with modified in accordance with the present disclosure. 
           [0015]      FIG. 4  is an enlarged side perspective view of the depth of cut scale feature of the present disclosure. 
           [0016]      FIG. 5  is an enlarged side perspective view of a depth of cut scale feature according to another disclosed embodiment. 
           [0017]      FIG. 6  is an enlarged side perspective view of the depth of cut scale shown in  FIG. 5  with the upper guard pivoted to a different DOC setting. 
           [0018]      FIG. 7  is an enlarged partial view of an alternative indicator arm usable with the depth of cut feature shown in  FIGS. 5-6 . 
           [0019]      FIG. 8  is an enlarged side perspective view of a depth of cut scale according to yet another disclosed embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains. 
         [0021]    The present disclosure pertains to a depth of cut (DOC) scale that is more easily viewed by the user, particularly when the user is standing upright over the saw while adjusting the DOC according to conventional practice. Referring first to  FIGS. 2-4 , a circular saw of the type shown in  FIG. 1  incorporates a depth of cut (DOC) scale  40  that includes a shelf  42  that is affixed to the upper guard  16  between the guard and the motor housing  12 . As best seen in  FIG. 4 , the shelf is slightly curved and is generally aligned with the upper end  24   a  of the DOC bracket  24  when the saw blade is at its initial or deepest cut position—i.e., when the adjustment rod  26  is at the base of the DOC slot  25 . The shelf  42  includes indicia  44  on its upper surface  43 , the indicia related to the depth of cut of the saw. The indicia  44  may be a typical DOC scale that emulates the scale  30 . However, unlike the scale  30 , the indicia  44  on the shelf is visible on a line of sight LOS that is directly above the saw, as depicted in  FIG. 3 . Thus, the operator can readily view the scale  44  of the DOC scale  40  with the saw  10  resting on the work surface or workpiece, according to the usual practice for adjusting DOC. 
         [0022]    The DOC scale  40  of the present disclosure includes a pointer that is essentially fixed relative to the upper guard  16  and shelf  42  as the guard is pivoted to adjust the depth of cut. The DOC scale includes a flexible element  48  that carries a pointer  49  that is readily visible along the line of sight LOS above the tool. In one embodiment the flexible element is a flexible strip that spans part of the width of the shelf  42  immediately adjacent the indicia  44 . The strip is thus configured to not overlap the indicia or otherwise impede a clear view of the DOC values. The pointer  49  is a visual indicator, such as a line or an arrow, or any indicator suitable to point toward the edge  48   a  of the flexible element and ultimately to point toward the indicia. Alternatively, the strip may cover the indicia with a transparent or open segment directly over the indicia through which the indicia may be viewed. In this alternative, the pointer may be in the form of a line or wire spanning the width of the transparent or open segment. In a further alternative, the flexible element may be a flexible wire with a pointer affixed thereto. 
         [0023]    The flexible element  48  is affixed at one end  48   b  to the DOC bracket  24  mounted to the foot  20 . The element  48  may thus be attached or affixed to an attachment member  52 . The attachment member  52  may be a post projecting from the upper end  24   a  of the bracket  24  and may be configured for releasable attachment of the end  48   b  of the flexible element. For example, when the flexible element is a flexible strip, the attachment member  52  may include a post having a slot along its length through which the strip extends. The end  48   b  of the strip may include a dowel affixed thereto that prevents withdrawal of the strip from the slot in the post. Regardless of the manner in which the strip is connected to the DOC bracket it is necessary that the end  48   b  be anchored to the DOC bracket and fixed relative to the rotatable upper guard  16 . 
         [0024]    The opposite end  48   c  of the flexible element  48  is connected to a tension mechanism  46 . The mechanism  46  is configured to maintain the flexible element  48  in tension across the surface  43  of the shelf  42  as the shelf pivots with the upper guard  16  during adjustment of the depth of cut. The slight curvature of the shelf  42  and the location of the shelf slightly above the attachment  52  and the tension mechanism  46  help maintain this tension. In one embodiment, the tension mechanism  46  includes a coil or torsion spring  50  with end  48   c  connected at an attachment point  54  to the spring. The manner of attachment of the end  48   c  may be similar to the manner of attachment of the end  48   b . The spring  50  is contained within a housing  51  that may be mounted to the upper guard  16 . The housing  51  defines an opening  51   a  through which the flexible element  48  extends, as shown in  FIG. 4 . The housing may be mounted immediately adjacent the shelf  42 , and may even be mounted to or integral with one end of the shelf, to minimize the length of the flexible element that is not supported by the shelf. 
         [0025]    At the maximum depth of cut position, an end portion  48   d  of the flexible element  48  is retracted within the housing  51  under force from the spring  50 . As the upper guard  16  is pivoted in the direction P ( FIG. 4 ) to decrease the DOC, more and more of the end portion  48   d  is paid out from the housing  51  in the direction E because the tension mechanism  46  moves away from the fixed end  48   b  of the flexible element. In essence, the scale  44  on the shelf  42  moves relative to the flexible element  48  and pointer  49 . As the end portion  48   d  is paid out from the housing  51 , the spring  50  winds more tightly to maintain continuous tension on the flexible element  48  and keep it tightly pressed against the surface  43  of the shelf as the shelf moves. 
         [0026]    As shown in  FIG. 4 , the tension mechanism  46  includes a wound spring. Other mechanisms are contemplated that are capable of maintaining the flexible element  48  in tension sufficient to keep the flexible element pressed against the shelf during pivoting to adjust DOC. For instance, the spring may be a plate spring or a helical spring mounted in an appropriate relationship with the shelf. As a further alternative, the end portion  48   d  of the flexible element  48  may be elastic or stretchable, with the end  48   c  mounted to the upper guard  16 . 
         [0027]    In one aspect, the line of sight DOC scale  40  may be a self-contained unit. In this embodiment, the tension mechanism  46  is connected to or integral with the shelf  42 . Mounting the housing  51  of the tension mechanism to the pivotably mounted assembly  11  (i.e., upper guard  16  or motor housing  12 ) also supports the shelf  42 . The flexible element  48  is connected at the end  48   c  to the tension mechanism, while the other end  48   b  is initially free or perhaps retracted within the housing  51 . When the scale  40  is mounted to the assembly, the flexible element can be extended across the upper surface  43  and the end  48   b  engaged to the depth adjustment bracket  24  at the attachment  52 . 
         [0028]    Referring now to  FIGS. 5-7 , another DOC scale  60  is illustrated that incorporates a curved arm  62  that is fixed relative to the pivoting assembly  11  that includes the saw  10 , motor housing  12  and upper guard  16 . In particular, the arm  62  may be connected to the depth adjustment bracket  24  that is fixed to the foot  20  on which the assembly is pivotably mounted, like the DOC scale  40  described above. The curved arm  62  may thus terminate in a hub or collar  64  that is attached to the bracket by a bolt  66  and nut  68 , or other suitable means. The collar and bolt arrangement serves as a pivot mount that allows the curved arm  62  to pivot relative to the upper end  24   a  of the bracket. The arm may be removably mounted to the bracket by way of the bolt and nut or other suitable means. 
         [0029]    Like the DOC scale  40 , the scale  60  shown in  FIG. 5  includes a shelf  82  that is connected to the pivoting assembly, such as to the upper guard  16 . The shelf includes DOC indicia  84  along the upper surface  83 . The curved arm  62  sits on the upper surface of the shelf  82  and rides along that surface as the shelf pivots with the guard  16  in the direction P, as depicted in  FIG. 6 . The curved arm  62  may freely pivot at the collar  64  so that the force of gravity maintains the arm in contact with the shelf. Alternatively, a biasing element, such as a coil or torsion spring, may be incorporated into the collar  64  to generate a downward torque on the arm  62 . This torque produces a downward force at the free end of the arm to hold the arm firmly in contact with the shelf. 
         [0030]    The curved arm  62  may be configured so that the side edge  70  is offset relative to the indicia  84  on the shelf so that the indicia are plainly visible adjacent the arm. The arm further includes a pointer  72  at the edge  70  to point to a DOC value. In an alternative embodiment, a curved arm  62 ′ shown in  FIG. 7  may be configured to cover all or part of the indicia so that the side edge  70 ′ overlaps the indicia  84  on the shelf. The free end  71 ′ of the arm defines a notch  72 ′ that is large enough for a DOC value to be fully visible within the notch. It can be appreciated that this version of the arm  62 ′ and pointer notch  72 ′ is best used with saws having discrete DOC adjustments, rather than saws capable of infinite DOC adjustment. In the latter case, the use of a pointer  72  of the arm  62  shown in  FIG. 5  may be desirable. 
         [0031]    The shelf  82  in this embodiment may have a greater curvature than the shelf  42  because the curved arm  62  is generally rigid. In order for the arm to ride generally flush with the upper surface  83  the shelf may be curved at a pivot radius relative to the pivot point  17  ( FIG. 2 ) of the pivoting assembly  11 . Alternatively, the arm  62  may exhibit some transverse flexibility to bend or flex when held in contact with the upper surface  83 , especially under torque from the biasing element described above. 
         [0032]    A depth of cut scale  90  shown in  FIG. 8  incorporates the cantilevered arm of the scale in  FIGS. 5-7 , but rather than overlying the indicia the cantilevered arm  92  is situated beneath the shelf  110 . In this embodiment, the arm  92  may include a pivot mount  94  with a bolt and nut connection  96 ,  98  (or other suitable means) similar to the arm  60  described above. However, the cantilevered end  100  of the arm is upturned and defines a generally U-shaped notch  102 . The upper branch  104  of the U-shape overlies the shelf  110  while the lower branch  106  of the U-shape is situated beneath the shelf. The edge  113  of the shelf is thus situated within the notch  102  so that the cantilevered end  100  of the arm  92  is supported and guided by the shelf  110 . The upper branch  104  may be configured as a pointer to point to a particular DOC indicia  114  as the upper guard  16  is pivoted. 
         [0033]    The arm  92  is pivotably mounted to the foot, such as by way of the adjustment bracket. This allows the arm to move freely as the shelf is pivoted with the pivoting assembly to adjust the DOC, and prevents the shelf edge  113  from binding within the notch  102 . In the embodiment shown in  FIG. 8 , the arm  92  is situated beneath the shelf so that the entire upper surface  113  of the shelf is visible, and the free end  100  is angled upward. The arm may be slightly curved toward the shelf to ensure clearance between the shelf and arm as the shelf pivots with the pivoting assembly  11 . 
         [0034]    Alternatively, the arm may be situated above the shelf but with the shelf edge  113  still situated within the notch  102 . In this configuration, the arm  92  would obscure or hide some of the indicia while the upper branch  104  is positioned immediately proximate the indicia corresponding to the current DOC. 
         [0035]    While the invention has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the invention are desired to be protected. 
         [0036]    For example, in the depth of cut scale disclosed herein, the shelf  42 ,  82  with the DOC indicia is fixed to the pivoting assembly  11 , while the elongated element is anchored to the DOC bracket  24 . Alternatively, the shelf could be fixed to the DOC bracket. With this modification, the connections for the flexible strip  48  would be reversed. In other words, the biasing spring and housing  46 ,  50  would be mounted to the DOC bracket, while the “fixed” end  48   b  of the strip would be fastened to the pivoting assembly. Likewise, the cantilevered arm  60  would be “anchored” to and pivot with the pivoting assembly  11 , while the free end and indicia  72  moves over the shelf.