Abstract:
A circular saw assembly of the type that includes a motor housing, a handle coupled to the motor housing, a generally circular saw blade disposed within a blade housing at a first end of the motor housing, and a foot member through which the blade extends for guiding the saw assembly along a work surface, where the circular saw assembly including a depth of cut locking system and an angle of cut locking system. The depth of cut locking system includes an arcuate bracket with an arcuate slot, and an engagement member extends through the slot and is operatively connected to the motor housing and slideable in the arcuate slot. The angle of cut locking system includes a bracket having an arcuate slot and an engagement member movable in the slot and configured to the bracket. A biasing member is provided to bias the engagement member, and at least one detent recess is provided to retain the engagement member therein.

Description:
[0001]     This application claims the benefit under 35 U.S.C. §119 of U.S. Provisional Application No. 60/537,436, filed on Jan. 16, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention generally relates to power tools and particularly to power hand tools.  
         [0003]     The power hand tools such as miter saws, circular saws, as well as other hand tools are often provided with the capability of adjusting the depth of cut or the bevel angle. Where such adjustability is provided in a tool, there is generally a measurement display and indicator present on the tool that will enable the user to set the angle or depth of cut at the desired location after which a locking lever is generally tightened to hold the tool in its desired position. Professional users often adjust the bevel and depth setting on circular saws, miter saws and other tools, which takes time and care to get the desired setting accurately. Because there are common angles such as 22½° and 45° for bevel angles, and particular thickness settings for depth of cut adjustments that correspond to common lumber thicknesses, e.g., ¼ inch, ½ inch, ¾ inch, 2 inches, it has been a practice for toolmakers to design the adjustable locking mechanisms to have detents at these common angles and depths.  
         [0004]     While there has been much time and energy directed to the design of detent mechanisms that are convenient to use and accurate, there is a continuing goal of designers to develop detent systems that have superior operating capability.  
       SUMMARY OF THE INVENTION  
       [0005]     A first preferred embodiment that is particularly useful in a depth of cut detent system utilizes a bracket having an arcuate slot therein with enlarged portions at the detent locations which enlarged portions generally encompass a circular shape that has a diameter that is slightly larger than the width of the slot at each detent location and wherein a locking member has a washer with a diameter larger than the width of the slot and the enlarged portions. The washer has a truncated conical extension adjacent an opening in the washer that defines an annular ramped portion that is sized to fit within the enlarged generally circular detent portions. A locking lever mechanism is spring biased toward the bracket so that the washer will engage the bracket at all times. However, the washer will not move to its fullest extent toward the bracket unless the conical extension fits within one of the enlarged circular portions, which are selectively positioned at specific predetermined locations that correlate to useful settings for users.  
         [0006]     A second preferred embodiment of the present invention is directed to a bevel detent system for a circular saw which has one or more detents at predetermined desired angular positions, where an elongated spring is positioned within a groove in which a portion of a locking lever is movable, wherein the spring engages the member that is moved in the slot and engages a recess at the desired detent location. The spring engages the locking member but is sufficiently flexible to allow the member to be moved along the slot. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a side perspective view of a circular saw and illustrating a bevel detent system as well as a portion of a depth of cut detent system;  
         [0008]      FIG. 2  is an enlarged perspective of a portion of the circular saw shown in  FIG. 2  and particularly illustrating the depth cut detent system shown at a location other than a detent location;  
         [0009]      FIG. 3  is an enlarged perspective of a portion of the circular saw shown in  FIG. 2  and particularly illustrating the system shown at a depth of cut detent location;  
         [0010]      FIG. 4  is a front view of the circular saw shown in  FIG. 1  and particularly illustrating a bevel quadrant and a portion of the bevel detent system;  
         [0011]      FIG. 5  is a plan view of a side of the washer that engages the locking lever portion of the depth cut detent system;  
         [0012]      FIG. 6  is a cross-section taken generally along the line  6 - 6  of  FIG. 5 ;  
         [0013]      FIG. 7  is a side view of the washer shown in  FIG. 5   
         [0014]      FIG. 8  is a plan view of the leaf spring;  
         [0015]      FIG. 9  is a side view of the leaf spring shown in  FIG. 8 ;  
         [0016]      FIG. 10  is a perspective view of the leaf spring shown in  FIG. 8 ;  
         [0017]      FIG. 11  is an end view of a portion of the leaf spring shown in  FIG. 8 ;  
         [0018]      FIG. 12  is a side elevational view of a saw with the preferred bevel detent system of the instant invention;  
         [0019]      FIG. 13  is a cross-section of the bevel detent system of  FIG. 12  taken generally along the line  13 - 13 ; and  
         [0020]      FIG. 14  is an enlarged portion of the bevel detent system illustrated in  FIG. 13 . 
     
    
     DETAILED DESCRIPTION  
       [0021]     There are two preferred embodiments that are shown in the drawings in connection with a circular saw. The first preferred embodiment is a depth of cut detent system that is used to quickly sense and adjust the amount by which the saw blade extends below the foot portion of the saw that effectively determines the depth of cut that can be made by the saw. The second preferred embodiment is directed to a bevel detent system that is provided with the circular saw to vary the bevel angle of the saw to a predetermined angle.  
         [0022]     While the preferred embodiments are shown in connection with a circular saw, it should be understood that the detent systems that are disclosed and described herein may be used with other hand tools or other types of mechanisms where detents are used to define desired commonly used positions for a mechanism and where a locking capability is desired to hold the mechanism in a desired position.  
         [0023]     Turning now to the drawings, and particularly  FIG. 1 , a circular saw is illustrated and generally shows a depth of cut detent system, indicated generally at  10 , as well as a bevel detent system, indicated generally at  12 . Both detent systems  10  and  12  are shown as being implemented in a circular saw of the type which has a motor housing  14 , a handle  16 , an auxiliary handle  18 , a foot structure  20 , as well as a blade housing  22  in which a saw blade is located. The saw may be adjusted to vary the depth of cut by using the depth of cut detent system  10  which enables the structure of the saw to pivot around an axis defined by a bolt  24 , with a locking mechanism  26  mounted on the handle structure  16  riding within an arcuate slot  28  provided in a generally arcuate bracket  30  that is mounted to the foot  20  by bolts, screws or other structure known to those of ordinary skill in the art.  
         [0024]     Similarly, the angle of the saw blade can be adjusted by a bevel adjusting structure that comprises a bevel bracket  32  that is preferably integrally formed with the foot structure  20  with the motor housing  14 , the saw blade housing  22  and saw blade being pivotable around an axis defined by a bolt  34 . An arcuate slot  36  within the bevel quadrant  12  is configured to have a constant radius from the bolt  34  and a locking lever mechanism  38  enables the bevel angle to be locked in place after it has been properly positioned, which can be done by a user with a pointer  39   a  in conjunction with a gauge  39   b  that is provided on the outer top surface of the quadrant  12 .  
         [0025]     Turning now to  FIGS. 1-3  with regard to the depth of cut detent system, the bracket  30  has a number of enlarged portions  40  that are generally circular configurations relative to a width of the slot  28 , and are preferably stamped cutout portions. The locking lever mechanism  26  has a lever handle  42 , that when rotated in the clockwise direction in  FIG. 1 , will cause the clamping mechanism to hold the saw at the set position relative to the foot structure  20 . In addition to the lever handle  42 , the locking lever mechanism includes a cylindrical portion  44  having an elongated cylindrical extension  46  extending axially between the handle  16  and the arcuate bracket  30 . While in the preferred embodiment the cylindrical extension is disposed within a sleeve  46   a , other embodiments contemplate the absence of a sleeve altogether. A threaded insert (not shown) is configured at an end of the cylindrical extension  46 . Similarly, a preferably threaded receiving member (not shown), such as a threaded stud, carriage bolt or the like extends from a side of the blade housing  22  that faces and engages the bracket  30  to threadedly engage the threaded insert extending from the cylindrical extension  46 , thus coupling the locking lever mechanism  26  to the blade housing. Thus, rotation of the lever handle  42  in the clockwise direction as illustrated in  FIG. 1  effects rotation of the threaded insert in the same direction, thereby clamping the bracket  30  between the threaded insert to the blade housing  22 .  
         [0026]     Conversely, when the lever  42  is moved in a counterclockwise direction with reference to  FIG. 1 , the extension  46  and the threaded insert will also turn in a counterclockwise direction, thereby loosening the threaded insert from the stud or carriage bolt. Once loosened, the motor housing  14 , blade housing  22  and handle  16  may move with respect to the arcuate slot  28  to vary the depth of cut of the blade.  
         [0027]     More specifically, when the locking lever  42  is moved in the clockwise direction, it will clamp the saw relative to the bracket  30  as desired. As shown in  FIGS. 2 and 3 , the bracket  30  preferably includes enlarged portions  40  at several locations along a length of the slot  28 , wherein the enlarged portions define specific depth settings of the saw blade as are shown on a scale to the left of the slots. These enlarged portions  40  are detents, which an experienced user may perceive and utilize by feel to place the circular saw at a predetermined desired depth. Once the desired depth is reached, the locking lever  42  may then be rotated (as illustrated in  FIGS. 1-3 , in the clockwise direction) to clamp and hold the saw at the desired position.  
         [0028]     To this end, a compression spring  50  is preferably disposed at an end of the cylindrical extension  46 , wherein the spring is configured at a first end to engage an internal rib  51  of the sleeve  46  in the preferred embodiment ( FIG. 3 ). At a second end, the spring is configured to engage a special washer  52  that is also provided in the preferred embodiment, and is configured to engage the enlarged portions and contact the side  62  of the bracket  30 . Other embodiments of the invention contemplate that where the sleeve  46   a  is absent, the spring  50  may extend from between the special washer  52  and the handle  16 .  
         [0029]     As shown in  FIGS. 5, 6  and  7 , the washer  52  preferably includes a main portion  54  that has the largest diameter, a cylindrical extension  56  on the top side as shown, and a truncated conical portion  58  on the lower side as shown, as well as a central opening  60  extending through the washer. The washer  52  is shown in  FIGS. 2 and 3  with a face  56   a  of the cylindrical extension  56  being in contact with the spring  50 , the spring having an inside diameter preferably only slightly larger than the diameter of the portion  56  so that it snuggly fits thereon. The truncated conical portion  58  is biased into contact with the surface  62  of the bracket  30 .  
         [0030]     While the depth of cut detent system may be locked at any predetermined depth, when the locking lever  42  is moved into a locking position, the position of the washer  52  relative to the surface will be different depending upon whether or not the common axis of the cylindrical extension  46  and bolt, as well as the washer itself, is located in an enlarged circular portion  40 . If the common axis is not in an enlarged portion  40 , because the diameter of the truncated conical portion  58  is larger than the width of the slot  28 , the main portion  54  will not be in contact with the surface  62 . In that position, the main portion  54  is spaced away from the surface  62  by an amount approximately equal to the height of the conical portion  58  and this spaced position is illustrated in  FIG. 2 . When the common axis of the cylindrical portion  46  is in a circular shaped enlarged portion  40 , the conical portion  58  will fit within the enlarged portion and the main portion  54  will be brought into contact with the surface  62  of the bracket. Thus, when desired, the detent system thereby accurately positions the saw in the desired position of one of the detents.  
         [0031]     The angle of the conical portion  58  is approximately 40° relative to the axis of the washer  52 , but may be varied to either a higher or lower angle if desired. A consideration for determining the angle of the conical portion  58  is that once the locking lever  42  is loosened, the angle of the conical portion  58  will affect how easily the saw can be moved within the slot  28 , when it is understood that a movement along the slot will create a force tending to push the washer  52  away from the bracket  30  as it disengages the circular enlarged portion  40 .  
         [0032]     Thus, in summary, the arcuate bracket  30  extends from the foot  20 , and is configured such that the locking lever mechanism  26  may engage and reciprocate within the slot  28  disposed within the bracket. Specifically, as the handle  16  and motor housing  14  are rotated with respect to the bolt  24 , the conical portion  58  of the washer  52  reciprocates along a trajectory defined by the arcuate slot  28  and enlarged portion  40 . At portions of the slot  28  that are not enlarged, the conical portion  58  does not matingly engage the slot, but abuts the surface  62  and may be locked into place via the threaded engagement of the threaded insert and the threaded stud, carriage bolt or the like extending from the side of the blade housing  22 . Threaded engagement and disengagement of the threaded insert and the threaded receiving member is promoted by rotation of the locking lever mechanism  26 , which as illustrated, is by rotation in the clockwise and counterclockwise directions respectively. At the enlarged portions  40  of the slot  28 , a user may perceive and utilize by feel a detent as the conical portion  58  is urged into the enlarged portion by the biasing member  50 . Since these enlarged portions  40  preferably correspond to predetermined depth of cut measurements, the user may perceive the detent and subsequently rotate the lever mechanism  26  to either engage or disengage the threaded insert and the threaded receiving member to lock the saw into that predetermined position.  
         [0033]     Turning now to the bevel detent system and referring to  FIGS. 4 and 8  through  14 , the bevel bracket  32  has the slot  36  as previously described into which a threaded fastener  69  such as a carriage bolt, stud or the like extends from a side of the slot facing the motor housing  14  and is secured from rotating by the bevel bracket  32 . A cylindrical portion  70  of the locking lever  38  extends through the slot  36  and threadedly engages the threaded fastener  69  from a side of the slot facing away from the motor housing. The operation of this locking lever  38  is substantially similar to that of the locking lever  26  previously described.  
         [0034]     More specifically, the threaded fastener  69  slides within the slot  36  to any position that is desired along a length of the slot. While the respective directions in which the locking lever  38  is rotated into locking and unlocking positions, as illustrated, the locking lever  38  is rotated in a clockwise direction into locking engagement. As illustrated in  FIGS. 12 and 13 , the threaded fastener  69  is operably engaged to the cylindrical portion  70  of the locking lever  38 , and a washer  71  is disposed between the cylindrical portion and a surface of the bevel bracket  32 . Thus, rotation of the locking lever  38  in the direction of locking engagement (clockwise as illustrated) compresses the bevel bracket  32 , the bevel quadrant  12 , the washer  71  and the cylindrical portion  70 , thereby locking the locking lever  38  into place, preferably via a clamping mechanism that clamps respective elements together to promote non-pivoting movement.  
         [0035]     The bevel bracket  32  additionally provides a detent system at predetermined increments along the length of the slot  36  to allow the user to perceive by feel a number of predetermined angular measurements. To this end, the bevel bracket  32  additionally includes a pair of curved protrusions  72  that have recess portions  74  between the protrusions  72  and a top wall  76  in which a leaf spring, indicated generally at  80 , is positioned. The leaf spring  80  has a pair of bowed flat portions  82  that extend into the slot  36  with the bowed portions having a cupped recess  84  positioned in the center of each bowed flat portion  82  to form a pair of detents that are preferably at the 22½° and 45° positions as is commonly provided with bevel detent systems. As a guide to the user, the bevel bracket  32  may optionally include measurement indicia.  
         [0036]     The threaded fastener  69  is configured and positioned to be moved along the slot  36  and when it reaches one of the recesses  84 , it will provide a detent and hold the angular position at the desired detent position whereupon the lever  38  can be rotated into locking engagement. As a guide, measurement indicia  86  may be provided along a top surface of the bevel bracket  32 . Since the leaf spring  80  is flexible, it may be locked in a position that is close to but not precisely centered into the detent  84  which enables the user to provide a bevel angle that can be locked in place at an angle very near the detent angles if desired. As is shown, the leaf spring  80  is preferably fabricated from a single piece of spring steel and it has bridging support portions  88 ,  90  and  92  that contact the inner surface of the end wall  76 . The leaf spring also has angled tabs  94  at each support portion which engage the opposite wall defined by the recess  74  to firmly hold the leaf spring in place. The angled tabs may assume a variety of configurations, such as rectangular or pointed, and for purposes of illustration only are shown as triangular.  
         [0037]     While various embodiments of the present invention have been shown and described, it should be understood that other modifications, substitutions and alternatives are apparent to one of ordinary skill in the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims.  
         [0038]     Various features of the invention are set forth in the following claims.