Abstract:
A power tool includes a working element, a motor, a motor actuator, a housing, a light emitting element, a locking element, and a switch element positioned between the housing and the locking element. The housing supports the motor, the motor actuator, and the light emitting element and movably supports the locking element. The light emitting element illuminates a work area around the working element, and the motor drives the working element when actuated by the motor actuator. The locking element enables operation of the motor actuator when in an unlocked position and prevents operation of the motor actuator when in a locked position. When in the unlocked position, the locking element operates the switch element to activate the light emitting element.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims priority to U.S. patent application Ser. No. 14/103,239, entitled “Circular Saw with Light Emitting Element System,” which was filed on Dec. 11, 2013 and which claims priority to U.S. Provisional Application No. 61/735,584, entitled “Circular Saw with LED Worklight System,” which was filed on Dec. 11, 2012, the disclosures of which are incorporated herein by reference in their entireties. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates generally to the field of hand-held power tools and, more particularly, to power tools having light emitting element systems. 
       BACKGROUND 
       [0003]    Hand-held power tools, such as circular saws, have been popular wood-working tools for many years. In a typical sawing operation, the user begins by marking or otherwise identifying a desired line along which to saw the material to be cut. The user then guides the saw during cutting, manually aligning the blade with the desired line of cut. Maintaining this alignment manually can be difficult because the typical circular saw has a blade guard that obscures the user&#39;s view of the blade at the point of cutting and thus impedes the user&#39;s ability to accurately align the blade with the desired cutting line. This same difficulty arises with other hand-held power tools, such as routers, coping saws, etc. 
         [0004]    To assist in the alignment, circular saws are typically provided with a guide slot that is usually located on the planar cutting base of the saw, and is positioned in front of, and in line with, the circular saw blade. The user then positions the saw so that the line on the material appears in the guide slot. While the provision of such a guide slot does aid the user in proper saw alignment, problems still exist. For example, because the guide slot is located in front of the blade, if the saw blade is not perpendicular relative to the workpiece, the guide slot might be positioned on the cut line while the blade is not. If the user begins to cut the material with the saw in this orientation, it is often difficult to correct the alignment problem. Additionally, because the blade is covered by a blade guard, the user cannot see the blade as it exits the material, and therefore cannot directly monitor the travel of the blade. 
         [0005]    Circular saws generally include any number of features meant to address the issues with visibility and alignment to improve the user&#39;s efficiency, accuracy, and safety while performing a cutting operation. For example, some circular saws include a lighting device to illuminate the portion of the workpiece being cut curing the cutting operation. Such lighting devices assist the user in manually aligning the circular saw blade with the cutting line drawn on the workpiece by enhancing visibility of the portion of the workpiece being cut. However, current circular saws including lighting devices employ complicated and costly mechanisms to actuate the lighting trigger button. Accordingly, there remains a need for lighting devices in circular saws that are simple and less complicated to implement. 
       SUMMARY 
       [0006]    A power tool includes a working element, and a motor drivingly coupled to the working element. For example, the power tool can be a circular saw including a saw blade. The power tool also includes a motor actuator configured to operate the motor and a housing configured to support the motor and motor actuator. The power tool also includes a light emitting element that is supported by the housing and is configured to illuminate a work area around the working element. A locking element is supported by the housing and movable between a locked position and an unlocked position. In the unlocked position the locking element enables the motor actuator to operate the motor, whereas in the locked position the locking element disables the motor actuator from operating the motor. In one aspect disclosed herein, the power tool includes at least one switch disposed between the housing and the locking element which is configured to operate the light emitting element when the locking element is in the unlocked position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a circular saw including a motor actuator. 
           [0008]      FIG. 2  is a schematic depiction of a locking element for use in the circular saw of  FIG. 1  shown in a locked position, and further depicting a switch according to one aspect of the present disclosure. 
           [0009]      FIG. 3  is a schematic depiction of the locking element of  FIG. 2  in an unlocked position and further depicting the switch actuated by the locking element. 
           [0010]      FIG. 4  is a schematic depiction of another locking element and switch for use in the circular saw of  FIG. 1  shown in a locked position. 
           [0011]      FIG. 5  is a schematic depiction the locking element and switch of  FIG. 4  in an unlocked position and the switch actuated. 
           [0012]      FIG. 6  is a schematic depiction of yet another locking element and switch for use in the circular saw of  FIG. 1  shown in a locked position. 
           [0013]      FIG. 7  is a schematic depiction of the locking element and switch of  FIG. 6  in an unlocked position and the switch actuated. 
           [0014]      FIG. 8  is a schematic depiction of a further locking element and switch for use in the circular saw of  FIG. 1  shown in a locked position. 
           [0015]      FIG. 9  is a schematic depiction of the locking element and switch of  FIG. 8  in an unlocked position and configured to operate a light emitting element. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    For the purposes of promoting an understanding of the principles of the disclosure, 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 disclosure is thereby intended. It is further understood that the present disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one of ordinary skill in the art to which this disclosure pertains. 
         [0017]      FIG. 1  depicts an embodiment of a cutting tool  100  having a housing  104 , a motor  108 , a working element  112 , a motor actuator  116 , a locking element  120  and a light emitting element  124 . The cutting tool  100  can be, for example, a saw, a drill, a tool bit or another device configured to penetrate into a workpiece. For illustrative purposes, the cutting tool  100  illustrated in  FIG. 1  is a circular saw and the working element  112  is a saw blade. The housing  104  is substantially hollow and houses electrical and mechanical components which operate the circular saw  100 . The motor  108  and motor actuator  116  are connected to and supported by the housing  104  with the motor actuator  116  accessible for a user to operate from outside the housing  104 . In one example, the motor actuator  116  is in the form of a trigger that can be depressed to activate the motor as is known in the art. The saw blade  112  is operably connected to the motor  108  such that the actuating motor  108  rotates the saw blade  112  as is known in the art. 
         [0018]    The light emitting element  124  is configured and positioned to illuminate a work area surrounding the saw blade  112  when the cutting tool  100  is in use. In the present embodiment, the light emitting element  124  is a light emitting diode. In an alternative embodiment, however, the light emitting element  124  can be any type of element configured to emit light such as, for example, an incandescent bulb or a fluorescent light. In the present embodiment, energy is provided to the light emitting element  124  by the same electrical system providing power to the motor  108 . In an alternative embodiment, however, energy can be provided to the light emitting element  124  by a separate energy source or a separate electrical connection. The light emitting element  124  is operated to illuminate the work area to improve the user&#39;s visibility of the workpiece being cut and, thus, the accuracy and alignment of the cut. In an alternative embodiment, the housing  104  can include an optical sensor (not shown) in combination with the light emitting element  124 . The optical sensor may be configured to illuminate the light emitting element  124  when a workpiece is positioned to be cut and to be actuated automatically when the motor is turned on or when the blade is rotating. Alternatively, the optical sensor can be configured to be actuated manually by the user via an on/off trigger. The optical sensor can be, for example, a light sensor or an ambient light sensing device. The optical sensor can also be configured to illuminate to compensate for poor light in an environment to allow a user to see and cut the workpiece. 
         [0019]    The housing  104  includes a handle portion  106  configured to be gripped by the user while operating the circular saw  100 . The handle portion  106  includes two locking element openings  126  (only one is visible in  FIG. 1 ) positioned on opposite sides of the housing  104  so as to mirror one another so that the locking element  120  is accessible through both openings. The handle portion  106  also includes a motor actuator opening  128  arranged on an underside of the handle portion  106  through which the actuator  116  projects for access by the user. The locking element openings  126  may be positioned to be easily reached by a user&#39;s thumb when grasping the handle portion  106 , whether the user grips the handle portion with the right or the left hand. The motor actuator opening  128  is positioned to be easily reached by the user&#39;s forefinger when the user is grasping the handle portion  106  to operate the circular saw  100 . 
         [0020]    Turning to  FIGS. 2 and 3 , the locking element  120  includes an actuator bar  130 , an internal portion  132  arranged along the actuator bar  130 , and may further include a biasing or detent member (not shown) operable to hold the actuator bar in a particular position until manually moved by the user. The locking element  120  also includes locking prongs  140  positioned on the internal portion  132  and separated by a locking gap  142  and a locking surface  144  and light actuation prongs  146 . The locking element  120  is supported by the housing  104  so as to extend through the locking element openings  126  such that, when the circular saw  100  is assembled as shown in  FIG. 1 , ends of the actuator bar  130  of the locking element  120  are positioned outside the housing  104  on opposite sides of the housing  104  and the internal portion  132  of the locking element  120  is positioned within the housing  104 . 
         [0021]    The locking element  120  is further supported by the housing  104  so as to be translationally movable within the locking element openings  126 , thereby enabling the locking element  120  to move between a locked position and an unlocked position. When the locking element  120  is in the locked position (shown in  FIG. 2 ), the internal portion  132  of the locking element  120  is centered within the housing  104  such that the ends of the actuator bar  130  of the locking element  120  extend evenly from both sides of the housing  104 . By applying pressure P to one of the ends of the actuator bar  130  with the user&#39;s thumb, the actuator bar  130  is moved inwardly toward the housing  104  and the locking element  120  is moved toward the unlocked position. When the actuator bar  130  can be pressed no further toward the housing  104 , the locking element  120  is in the unlocked position (shown in  FIG. 3 ). Pressure P can be applied to either of the two ends of the actuator bar  130  to move the locking element  120  into the unlocked position. The biasing member or detent may be configured to bias the locking element  120  into the locked position once the actuator bar  130  has moved laterally a sufficient distance. The biasing member or detent may be configured so that an opposite pressure applied to move the locking element  120  back to the locked position must overcome the biasing or detent force. 
         [0022]    The motor actuator  116  includes an external portion  134  and an internal portion  136 . The internal portion  136  of the motor actuator  116  includes an engaging projection  150 . The engaging projection  150  is sized and configured to fit between the locking prongs  140  of the locking element  120  Like the locking element  120 , the motor actuator  116  is supported by the housing  104  so as to extend through the motor actuator opening  128  such that, when the circular saw  100  is assembled, the external portion  134  of the motor actuator  116  is positioned outside the housing  104  and the internal portion  136  of the motor actuator is positioned within the housing  104 . When the user operates the circular saw  100 , the user can easily reach the external portion  134  extending from the underside of the handle portion  106  with his forefinger. The external portion  134  may be configured as a trigger as is known in the art. 
         [0023]    The motor actuator  116  is further supported by the housing  104  so as to be pivotably movable within the motor actuator opening  128 , thereby enabling the motor actuator  116  to pivot between a non-actuated position, in which the motor actuator  116  is not able to operate the motor  108 , and an actuated position, in which the motor actuator  116  is able to operate the motor  108 . When the locking element  120  is in the locked position (shown in  FIG. 2 ), the engaging projection  150  is aligned with the locking gap  142 . Accordingly, when the motor actuator  116  is pivoted inwardly, toward the actuated position, the engaging projection  150  contacts the locking surface  144 , thereby preventing the motor actuator  116  from entering the actuated position and retaining the motor actuator  116  in the non-actuated position such that the motor actuator  116  is not able to actuate the motor  108  to operate the saw blade  112 . Conversely, when the locking element  120  is in the unlocked position (shown in  FIG. 3 ), the engaging projection  150  is not aligned with the locking gap  142 . Accordingly, the motor actuator  116  is able to be pivoted inwardly without interference into the actuated position, such that the motor actuator  116  is able to actuate the motor  108  to operate the saw blade  112  of the circular saw  100 . 
         [0024]    The circular saw  100  further includes a switch element  154  disposed between the housing  104  and the locking element  120 . In one embodiment, the switch element  154  is supported by a rib  155  within the housing  104  and configured to extend into a gap  148  between the light actuation prongs  146  positioned on the internal portion  132 . The switch element  154  may include a printed circuit board  156  and two micro-electro-mechanical (MEM) switches  158  surface mounted to the printed circuit board  156 . The printed circuit board is electrically connected to the light emitting element  124  such that actuation of either of the switches  158  operates the light emitting element  124 . The switches  158  are mounted on opposite sides of the printed circuit board  156  such that the switches  158  are positioned opposite one another and face away from one another, and more importantly the switches  158  are positioned to face a corresponding one of the light actuation prongs  146 . 
         [0025]    When the locking element  120  is positioned in the locked position (shown in  FIG. 2 ), the light actuation prongs  146  are spaced apart from the switches  158  and the light emitting element  124  (shown in  FIG. 1 ) is not operated. When the locking element  120  is moved into the unlocked position (shown in  FIG. 3 ), one of the light actuation prongs  146  comes into contact with one of the MEM switches  158 , thereby electrically operating the light emitting element  124  (shown in  FIG. 1 ). Accordingly, when a user moves the locking element  120  to unlock the circular saw  100  to enable operation of the motor actuator  116  to actuate the motor  108  and operate the saw  100 , the user also automatically operates the light emitting element  124  to illuminate the work area surrounding the saw blade  112 . In an alternative embodiment, the printed circuit board  156  can also be movable relative to the housing  104  such that the light emitting element  124  can also be operated by moving the printed circuit board  156  without moving the locking element  120 . In this embodiment, the printed circuit board  156  can be moved laterally to depress one of the MEM switches against the stationary light actuation prong  146 . The printed circuit board  156  may thus be supported on an actuator that is externally accessible on the housing  104 . In another alternative embodiment, the switch element  154  can include a single switch  158  surface mounted to the printed circuit board  156  instead of two switches  158 . The single switch  158  is configured and positioned such that it can be contacted by either of the light actuation prongs  146  to operate the light emitting element  124 . 
         [0026]    Turning now to  FIGS. 4 and 5 , a locking element  120 ′ and a switch element  154 ′ are shown. The locking element  120 ′ and switch element  154 ′ are substantially similar to the locking element  120  and switch element  154  shown in  FIGS. 1 and 2 . However, the locking element  120 ′ includes capacitive electrode switches  158 ′ mounted to the light actuation prongs  146 ′ and the switch element  154 ′ does not include MEM switches. The capacitive electrode switches  158 ′ are positioned opposite one another, separated by the gap  148 ′, face toward one another and more importantly face the printed circuit board  156 ′ situated between the light actuation prongs  146 ′. 
         [0027]    In use, the light emitting element  124  (shown in  FIG. 1 ) is operated by moving the locking element  120 ′ between the locked position (shown in  FIG. 4 ) and the unlocked position (shown in  FIG. 5 ). When the locking element  120 ′ is in the locked position (shown in  FIG. 4 ), the light actuation prongs  146 ′ are spaced apart from the printed circuit board  156 ′ and the light emitting element  124  is not operated. When the locking element  120 ′ is moved to the unlocked position (shown in  FIG. 5 ), one of the switches  158 ′ on one of the light actuation prongs  146 ′ contacts the printed circuit board  156 ′ thereby operating the light emitting element  124  (shown in  FIG. 1 ). In an alternative embodiment, the printed circuit board  156 ′ can also be movable relative to the housing  104  such that the light emitting element  124  (shown in  FIG. 1 ) can also be operated by moving the printed circuit board  156 ′ without moving the locking element  120 ′. 
         [0028]    Turning now to  FIGS. 6 and 7 , a locking element  120 ″ and a switch element  154 ″ are shown. The locking element  120 ″ and switch element  154 ″ are substantially similar to the locking element  120  and switch element  154  shown in  FIGS. 1 and 2  and described above. However, the locking element  120 ″ does not include the light actuation prongs and gap and instead includes an actuation rib  160 ″. The switch element  154 ″ includes light actuation prongs  162 ″, supported by the housing  104 , and a gap  164 ″ separating the two light actuation prongs  162 ″. The actuation rib  160 ″ is configured and positioned to extend into the gap  164 ″ between the light actuation prongs  162 ″. Each of the light actuation prongs  162 ″ may include a printed circuit board  156 ″ electrically connected to the light emitting element  124  (shown in  FIG. 1 ) and a micro-electro-mechanical switch  158 ″ surface mounted to the printed circuit board  156 ″. The switches  158 ″ are positioned opposite one another, separated by the gap  164 ″ and facing toward one another and toward the actuation rib  160 ″. 
         [0029]    In use, the light emitting element  124  (shown in  FIG. 1 ) is operated by moving the locking element  120 ″ between the locked position (shown in  FIG. 6 ) and the unlocked position (shown in  FIG. 7 ). When the locking element  120 ′ is in the locked position (shown in  FIG. 6 ), the actuation rib  160 ″ is spaced apart from the printed circuit boards  156 ″ and the light emitting element  124  is not operated. When the locking element  120 ″ is moved to the unlocked position (shown in  FIG. 7 ), the actuation rib  160 ″ contacts one of the switches  158 ″ on one of the printed circuit boards  156 ″ supported by the housing  104 , thereby operating the light emitting element  124  (shown in  FIG. 1 ). 
         [0030]    Turning now to  FIGS. 8-10 , a locking element  120 ″′ and a switch element  154 ″′ are shown. The locking element  120 ″′ and switch element  154 ″′ are substantially similar to the locking element  120 ″ and switch element  154 ″ shown in  FIGS. 6 and 7  and described above. However, the locking element  120 ″′ includes a variable resistor  166 ′″ and circuit wiper  168 ″′ configured to control activation of an actuator  160 ″′ within the gap  164 ″′. When activated, the actuator moves toward one of the light actuation prongs  162 ″′ to thereby activate the lighting emitting element  124 . The actuator  160 ″′ is thus configured to move independently of the locking element  120 ″′. When the locking element  120 ″′ is in the locked position (shown in  FIG. 8 ), the actuator  160 ″′ is spaced apart from the printed circuit boards  156 ″′ and the MEM switches  158 ″′. In this position, the circuit wiper  168 ″′ is oriented in the center of the variable resistor  166 ″′ so that the current provided to the actuator  160 ″′ is not sufficient to cause the actuator to move. When the locking element  120 ″′ is moved to the unlocked position (shown in  FIG. 9 ), the circuit wiper  168 ″′ contacts the variable resistor  166 ″′ at a different location so that sufficient current is provided to activate the actuator  160 ″′ to move into contact with one of the MEM switches  158 ″′ to thereby activate the light emitting element  124 . The actuator  160 ″′ may be a solenoid or similar electrical component that requires a threshold current to be activated. 
         [0031]    The arrangements of the circular saw  100  as described above are advantageous because the locking element  120 ,  120 ′,  120 ″, or  120 ″′ is a safety switch which the user must move before the user can actuate the motor actuator  116 . This promotes safety by decreasing the chance that the user unintentionally actuates the motor actuator  116  and unintentionally operates the circular saw  100 . Additionally, these arrangements are advantageous because the user operates the light emitting element  124  using a single integrated direct contact actuation mechanism rather than a costly, complex mechanism. Moreover, the switch elements  154 ,  154 ′,  154 ″,  154 ″′ eliminate the need for a separate switch to activate a light, which can take the user&#39;s attention away from the power tool. These arrangements are further advantageous because they are able to be actuated by a user with either his right or his left hand, improving versatility and usability. 
         [0032]    In other embodiments, the printed circuit boards of the prior embodiments can be flexible circuits, foldable circuits, ceramic substrates, thin film multichip module substrates, prefolded substrates, a combination thereof, or another substrate material having similar properties. In other embodiments, the micro-electo-mechanical switches of the prior embodiments can be micro-electro-mechanical system switch-like elements such as cantilever beams, torsional beams, sliding disks, and other micro-electo-mechanical elements which are well known in the art. In other alternative embodiments, the micro-electo-mechanical elements can be joystick movement micro-electo-mechanical sensors. The micro-electo-mechanical switches can be controllable by a variety of means known in the art, including but not limited to electrostatic means, capacitive means, magnetic means, or piezoelectric means. In yet other embodiments, the switches can be fabricated and integrated within the circuit boards. 
         [0033]    In at least one embodiment, the light emitting element  124  is configured to emit light at a variety of intensity levels. In one embodiment, the light emitting element  124  emits light at a “low” intensity level when the user is not depressing the locking element  120 ,  120 ′,  120 ″, or  120 ″′ and emits light at a “high” intensity level when the user is depressing the locking element  120 ,  120 ′,  120 ″, or  120 ″′. In another embodiment, the light emitting element  124  emits light with gradually increasing intensity when the user has depressed the locking element  120 ,  120 ′,  120 ″, or  120 ″′ and is depressing the motor actuator  116 . In another embodiment, the light emitting element  124  emits light at a “high” intensity level when the user is depressing the motor actuator  116  and emits light at a “low” intensity level when the user releases the motor actuator  116 . In another embodiment, the light emitting element  124  emits light at a “high” intensity level when the user is depressing the motor actuator  116  and emits light in flashes when the user releases the motor actuator  116 . In this embodiment, the light emitting element  124  emits light at a “low” intensity level after emitting light in a predetermined number of flashes. 
         [0034]    In the embodiments described herein, the light emitting element is able to be actuated by movement in either a right or a left direction. In alternative embodiments, the light emitting element can be actuated in the same manner but only by movement in one of the right or left direction. 
         [0035]    While the disclosure 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 disclosure are desired to be protected.