Abstract:
A powered hand tool includes a motor, a cutting member drivable to cut a workpiece, and a drive system interconnecting the motor and the cutting member and operable to drive the cutting member in response to operation of the motor. A housing at least partially encloses the cutting member and the motor and a debris removal system is movable between a first position and a second position. The debris removal system is operable to clean a portion of the drive system when in the second position. The debris removal system includes an abrasive member, an automatic actuator, and a sensor operable to selectively generate a signal. The automatic actuator is movable between an actuated position in which the abrasive member moves to the second position and a non-actuated position in which the abrasive member moves to the first position in response to the sensor.

Description:
RELATED APPLICATION DATA 
     This application is a continuation of U.S. application Ser. No. 12/509,159 filed Jul. 24, 2009, now U.S. Pat. No. 8,397,390, which claims benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Application No. 61/083,732, filed Jul. 25, 2008, both of which are fully incorporated herein by reference. 
    
    
     BACKGROUND 
     The present invention relates to a system for removing debris from power tool components, and more particularly, from band saw components. 
     Band saws may be various sizes to accommodate various cutting applications, and typically include a drive wheel pulley, a driven wheel pulley and a continuous saw blade positioned around the drive wheel and the driven wheel. The saw blade is driven by the drive wheel to cut work pieces (e.g., metal, wood, etc.). As the saw blade cuts the work piece, the saw blade picks up chips (e.g., metal chips, wood chips, etc.), which can embed in a blade tire of the respective wheel. The embedded chips may cause the saw blade to slip with respect to the blade tire and the wheel. When debris embeds in the blade tire, the cutting capabilities of the band saw decrease, thereby requiring removal of the blade tire for replacement or cleaning. 
     SUMMARY 
     In one construction, the invention provides a powered hand tool that includes a handle portion arranged to provide a grip point for a user, a motor, a cutting member drivable to cut a workpiece, and a drive system interconnecting the motor and the cutting member and operable to drive the cutting member in response to operation of the motor. A housing at least partially encloses the cutting member and the motor and a debris removal system is movable between a first position and a second position. The debris removal system is operable to clean a portion of the drive system when in the second position. 
     In another construction, the invention provides a powered hand tool that includes a housing having a handle portion arranged to provide a grip point for a user, a first blade tire rotatable about a first axis, and a second blade tire rotatable about a second axis. The first axis and the second axis are positioned a non-zero distance from one another and are arranged substantially parallel to one another. A continuous saw blade is positioned to extend around a portion of the first blade tire and a portion of the second blade tire and a motor is positioned at least partially within the housing and is operable to drive the first blade tire to move the blade along a continuous path to cut a workpiece. A debris removal system has an abrasive member positioned substantially within the housing and an actuator portion positioned at least partially outside of the housing. The debris removal system is movable between a first position and a second position in which the abrasive member is operable to clean a portion of one of the first blade tire and the second blade tire. 
     In yet another construction, the invention provides a powered hand tool that includes a first blade tire that is rotatable about a first axis and a second blade tire rotatable about a second axis. The first axis and the second axis are positioned a non-zero distance from one another and are arranged substantially parallel to one another. A continuous saw blade is positioned to extend around a portion of the first blade tire and a portion of the second blade tire and a motor is operable to drive the first blade tire to move the blade along a continuous path to cut a workpiece. An abrasive member is movable between a first position and a second position in which the abrasive member contacts one of the first blade tire and the second blade tire to remove debris produced during the cutting of the workpiece. An actuator portion is movable between a non-actuated position and an actuated position. Movement to the actuated position moves the abrasive member to the second position. 
     In another construction, the invention provides a powered hand tool that includes a handle portion arranged to provide a grip point for a user, a motor, a cutting member drivable to cut a workpiece, and a drive system interconnecting the motor and the cutting member and operable to drive the cutting member in response to operation of the motor. A housing at least partially encloses the cutting member and the motor and a debris removal system is movable between a first position and a second position. The debris removal system is operable to clean a portion of the drive system when in the second position. The debris removal system includes an abrasive member, an automatic actuator, and a sensor operable to selectively generate a signal. The automatic actuator is movable between an actuated position in which the abrasive member moves to the second position and a non-actuated position in which the abrasive member moves to the first position in response to the sensor. 
     In yet another construction, the invention provides a powered hand tool that includes a housing including a handle portion arranged to provide a grip point for a user, a first blade tire rotatable about a first axis, and a second blade tire rotatable about a second axis. The first axis and the second axis are positioned a non-zero distance from one another and are arranged substantially parallel to one another. A continuous saw blade is positioned to extend around a portion of the first blade tire and a portion of the second blade tire, a motor is positioned at least partially within the housing and is operable to drive the first blade tire to move the blade along a continuous path to cut a workpiece, and a debris removal system has an abrasive member positioned substantially within the housing and an actuator portion positioned at least partially outside of the housing. The debris removal system is movable between a first position and a second position in which the abrasive member is operable to clean a portion of one of the first blade tire and the second blade tire. The actuator portion includes a sensor and an automatic actuator. The automatic actuator moves the abrasive member from the first position to the second position in response to a signal from the sensor. 
     In another construction, the invention provides a method of cleaning a powered hand tool having a continuous saw blade. The method includes rotating a first blade tire to rotate the continuous saw blade and a second blade tire, sensing a condition related to the powered hand tool that is indicative of a level of debris collected during operation of the powered hand tool, and generating a signal in response to the condition exceeding a predefined level. The method further includes moving an automatic actuator from a non-actuated position to an actuated position in response to the signal and moving an abrasive member in response to movement of the automatic actuator from a first position to a second position in which the abrasive member is operable to clean a portion of one of the first blade tire and the second blade tire. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a band saw suitable for use with the debris removal system; 
         FIG. 2  is a perspective view of a debris removal system incorporated into the band saw of  FIG. 1 ; 
         FIG. 3  is another perspective view of the debris removal system of  FIG. 2  in a first or non-actuated position; 
         FIG. 4  is a perspective view of the debris removal system of  FIG. 2 , in a second or actuated position; and 
         FIG. 5  is a perspective view of an automatically actuated debris removal system incorporated into the band saw of  FIG. 1 . 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
       FIGS. 1-4  illustrate a band saw  10  that includes a debris removal system  94  according to one embodiment of the invention.  FIG. 1  illustrates an AC version of the band saw  10  having an electrical connection cord  12 . However, other embodiments may be applied to DC versions of the band saw  10  which includes one or more rechargeable battery packs that are preferably removable. 
     The band saw  10  includes a housing or frame  14  supporting a motor  18  and a drive system including a gear box  22 . The motor  18  is drivingly connected to a drive mechanism (not shown) at least partially housed within the gear box  22 . The motor  18  and the drive mechanism are operable to drive a continuous band saw blade  26  to cut a work piece. As described herein, the band saw  10  includes a front  30  and a rear  34 . The front  30  is defined as the side being proximate the portion of the band saw blade  26  that cuts the work piece and the rear  34  is defined as the side proximate the portion of the band saw blade  26  that does not cut the work piece. The rear  34  is otherwise described as being opposite the front  30 . 
     The housing  14  includes a main handle  38  supporting a switch assembly  42  to control power to the band saw  10 . The switch assembly  42  is operable by the user to selectively control operation of the motor  18 . The band saw  10  also includes an auxiliary handle  46  for a user&#39;s other hand. Generally, the handles  38 ,  46  are shaped and arranged for two-handed operation of the band saw  10  as the work piece is cut. In the illustrated embodiment, each handle  38 ,  46  has an ergonomic design to provide comfortable gripping and controlled operation of the band saw  10 . The ergonomic design of each handle  38 ,  46  and of the combination of the handles may include the orientation or angle of handle(s). The ergonomic design may also include the use of material, such as an elastomeric material, on the handle(s)  38 ,  46  to, one or more of, provide an improved grip surface, isolate vibration and impacts from the operator, prevent heat build-up and/or transfer to the operator, etc. 
     The housing  14  defines a first portion  50  and a second portion  54 . The first portion  50  and the second portion  54  are spaced apart from one another and define a U-shaped cavity  66  defining a cut zone  58  therebetween. A blade guard  62  ( FIGS. 2-4 ) is positioned at the rear  34  of the band saw  10  and extends between the first and second portions  50 ,  54  within the cut zone  58 . The blade guard  62  is positioned along the rear  34  of the band saw  10  and provides a recessed area to house the band saw blade  26 . In the illustrated embodiment, the blade guard  62  extends parallel to the portion of the band saw blade  26  in the cut zone  58  at the front  30  of the band saw  10 . 
     As shown in  FIGS. 2-4 , the band saw  10  generally includes a drive wheel pulley  70  and a driven wheel pulley  71 . The drive wheel  70  rotates about a drive wheel axis  78  (shown in  FIG. 2 ) and is drivingly connected to the motor  18  via a drive system  79 . The driven wheel  71  rotates about a driven wheel axis  82  and is rotatably supported by the housing  14 . The drive wheel  70  is positioned in the first portion  50  of the housing  14 , and the driven wheel is positioned in the second portion  54  of the housing  14 . A blade tire  86  is coupled to each of the peripheries of the drive wheel  70  and the driven wheel  71 . Each blade tire  86  is a circular-shaped ring formed of a soft and/or flexible elastomeric material that is able to lock or adhere to the respective wheel. The band saw blade  26  extends around the drive wheel  70  and the driven wheel  71  and is gripped by the blade tires  86 . In this way, motion from the drive wheel  70  is transmitted to the band saw blade  26  via the blade tires  86 . The band saw  10  may also include a blade tensioning mechanism  90  to adjustably provide appropriate tension on the band saw blade  26 . The band saw may also include a shoe  92  for positioning against the work piece. 
     The amount of grip or friction between the blade tires  86  and the band saw blade  26  depends, in part, on the tension in the band saw blade  26  and on the coefficient of friction between the blade tire  86  and the blade  26 . The greater the friction between the blade tires  86  and the band saw blade  26 , the greater the pull force on the band saw blade  26  by the blade tires  86  as the wheels rotate. The band saw blade  26  is designed to continuously loop about a circuit formed between the drive wheel  70  and the driven wheel  71 . The band saw blade  26  generally engages approximately 180 degrees of the circular blade tire  86 , while the remaining approximately 180 degrees of the blade tire  86  is separated from the band saw blade  26 . 
     With reference to  FIGS. 2-4 , the band saw  10  includes a debris removal system  94  for cleaning debris from the blade tire  86 . The debris may be from chips (e.g., metal or wood chips) from the work pieces or any debris that can be embedded into the elastomeric blade tire  86 . The debris removal system  94  is positioned toward the rear  34  of the band saw  10 , proximate the blade guard  62 . The debris removal system  94  is coupled to an underside of the first portion  50  of the housing  14  and includes an abrasive  98  and a biasing member or spring  102  coupled to the abrasive  98 . The abrasive  98  is positioned in the first portion  50  and adjacent to the blade tire  86  of the drive wheel  70  at a segment of the blade tire  86  that is not engaged with the band saw blade  26 . In the illustrated embodiment, the abrasive  98  is a wire brush that scrapes the blade tire  86  to clean or remove debris therefrom. In other embodiments, the abrasive  98  is formed from a variety of materials or substrates that provide a roughened surface for contacting and cleaning the blade tire  86 . 
     The spring  102  is a flat spring (leaf spring) that biases the abrasive  98  away from the blade tire  86 , and includes a first end  114  and a second end  116  (shown in  FIG. 3 ). The spring  102  extends through an aperture  110  ( FIG. 3 ) formed in the first portion  50  of the housing  14  such that the first end  114  is positioned inside the first portion  50  and the second end  116  is positioned outside the first portion  50  (i.e., within the cavity  66 ). The first end  114  of the spring  102  is coupled to the abrasive  98 , and the second end  116  of the spring  102  is coupled to the housing  14  using fasteners  106  or other suitable attachment means (e.g., adhesive, clamps, etc.). In other embodiments, the spring  102  is positioned anywhere on the housing such that the abrasive  98  is able to engage the blade tire  86 . In still other embodiments, the wheel is open to the cavity  66  and the spring  102  and the abrasive  98  are positioned in the cavity to engage with the blade tire  86  of the wheel. The drive wheel  70 , and therein the blade tire  86 , rotate such that the abrasive  98  removes debris from the blade tire  86  as the drive wheel  70  rotates, and in some embodiments, prior to engagement of the blade tire  86  with the band saw blade  26 . 
     With continued reference to  FIGS. 2-4 , the debris removal system  94  further includes an actuator or button  118  and an actuator spring  122  compressed by the actuator  118 . The actuator  118  is substantially cylindrical shaped, and includes a first hub  126  and a second hub  130  positioned at opposing ends of the actuator  118 . The first hub  126  provides an area for a user to manipulate the actuator  118 , and the second hub  130  is positioned proximate the spring  102  for engaging and moving the spring  102 . The actuator  118  is movable between a first position in which the actuator  118  does not displace the spring  102  and a second position in which the actuator  118  engages and displaces the spring  102 . The abrasive  98  engages the blade tire  86  in response to movement of the actuator  118  to the second position. When the actuator  118  is released, the actuator spring  122  biases the actuator  118  to the first position and the spring  102  biases the abrasive  98  to the non-contact position illustrated in  FIG. 2 . In other embodiments, other actuators may be used to engage the abrasive  98  with the blade tire  86 . 
     The actuator spring  122  is a coil compression spring, and is positioned around the actuator  118  and compressed between the first hub  126  and a shoulder  134  of the debris removal system  94  that is proximate the housing  14 . The actuator spring  122  biases the actuator  118 , and in particular the second hub  130 , away from the spring  102 .  FIGS. 2 and 3  illustrate the actuator  118  in a neutral or release position biased away from the spring  102  by the actuator spring  122 . To engage the abrasive  98  with the blade tire  86 , and thereby move the actuator  118  into a cleaning position (shown in  FIG. 4 ), the actuator  118  (i.e., the first hub  126 ) is pressed by a user&#39;s hand, as shown in  FIG. 4 . The force applied by the user causes the actuator  118  to move toward the spring  102  against the biasing force of the actuator spring  122 . The second hub  130  of the actuator  118  pushes the spring  102  against the biasing force of the spring  102  until the abrasive  98  engages the blade tire  86  to remove debris from the tire  86 . 
     In some embodiments, an automated debris removal system  199  is employed. For example,  FIG. 5  illustrates a construction in which a sensor  200  is positioned adjacent the blade tire  86  to count revolutions of the blade tire  86 . A controller  205 , such as a simple micro-controller or integrated circuit includes a counter that counts the revolutions of the blade tire  86  and generates a signal when the number of revolutions exceeds a predetermined number. The controller  205  then resets the counter to zero and begins counting again. The signal is transmitted to an electromechanical device  210  such as a solenoid, a motor, a piezoelectric element, or, as illustrated in  FIG. 5 , a simple electromagnet arrangement. In the construction of  FIG. 5 , the electromechanical device  210  is positioned adjacent the leaf spring  102 . The signal from the controller  205  actuates a switch  215  that energizes the electromechanical device  210 . A permanent magnet  220  may be attached to the leaf spring  102  to assure that when the electromechanical device  210  is energized, the leaf spring  102  is repelled rather than attracted. After a predetermined time period or a predetermined number of revolutions, the electromechanical device  210  is deenergized and the cycle repeats. Thus, in the automated construction of  FIG. 5 , the user does not need to actuate the debris removal system. Rather, the system automatically periodically removes debris. 
     In other automated systems, the leaf spring  102  may be arranged to bias the abrasive member  98  into contact with the blade tire  86 . In these constructions, the electromechanical device  210  is energized when cleaning is not occurring. While this arrangement is possible, it would result in reduced battery life or additional power consumption. 
     In other embodiments, the debris removal system  94  (manual or automatic) can be positioned at other points along the exposed portion of the blade tire  86  of the drive wheel  70  such that the abrasive  98  cleans the blade tire  86  prior to engagement with the band saw blade  26 . In still other embodiments, the debris removal system  94  is coupled to the second portion  54  of the housing  14  and the abrasive  98  is positioned proximate the blade tire of the driven wheel  71 . In yet another embodiment, the band saw  10  includes more than one debris removal system  94  for removing debris from either or both of the blade tires. 
     In operation, the band saw blade  26  rotates about the drive wheel  70  and the driven wheel. The drive wheel  70  is driven by the motor  18  and the drive system or mechanism. As the drive wheel  70  rotates, the blade tire  86  frictionally engages or grips the band saw blade  26  to transmit the rotational movement of the drive wheel  70  to the band saw blade  26 . The movement of the band saw blade  26  cuts a work piece and, in some cases, produces debris (e.g., chips). The debris is prone to enter the housing  14  and attach to or embed in the blade tire  86 . 
     To remove the debris and clean the blade tire  86 , the debris removal system  94  can be periodically actuated by a user while the band saw is operating. As shown in  FIG. 4 , a user presses the actuator  118  to move it toward the second position against the biasing force of the actuator spring  122 . The second hub  130  of the actuator  118  contacts the second end  116  of the abrasive spring  102  and forces (i.e., deflects) the abrasive spring  102  toward the blade tire  86 . The abrasive  98  engages the blade tire  86 , and begins to scrape and remove debris on or embedded in the blade tire  86 . In the illustrated embodiment, the debris removal system  94  removes debris when the band saw blade  26  is in operation. However, other embodiments may include a system that removes debris when the band saw  10  is turned OFF. 
     In constructions that employ the automated debris removal system  194  of  FIG. 5 , the user simply uses the band saw as if it had no system  199 . The sensor  200  detects each revolution of the blade tire  86  and the counter counts those revolutions. Once the number of revolutions exceeds a predetermined number, the micro-controller  205  generates a signal to close a switch  215  (e.g., transistor, relay, etc.) and energize the electromechanical device  210 . The electromechanical device  210  is positioned adjacent the permanent magnet  220  arranged to have the same polarity as the electromechanical device  210  when energized. Thus, the electromechanical device  210  repels the permanent magnet  220  and the leaf spring  102  to which it is attached to push the abrasive member  98  into contact with the blade tire  86  to clean the blade tire  86 . A timer or the sensor  200  and counter assures that the abrasive  98  remains in contact with the blade tire  86  for a sufficient time or a sufficient number of revolutions before the electromechanical device  210  is deenergized. 
     Removal of debris from the blade tires  86  reduces band saw blade slippage and reduces the likelihood of the blade  26  falling off the drive wheel  70  and/or the driven wheel  71 . Debris reduces the coefficient of friction between the blade tire  86  and the blade  26  and degrades the pull force on the blade  26  from the blade tires  86 , thereby decreasing the cutting capability of the blade  26 . By removing the debris, the gripping capabilities and the coefficient of friction increase such that the blade tire  86  is able to transmit rotation and thereby maintain the cutting force provided by the band saw blade  26 . 
     In other embodiments, the actuator  118  is alternately positioned in another position on the band saw  10 , such as, for example, on a top side  182  ( FIG. 1 ) of the housing  14 . In these constructions, a linkage arrangement may be employed to produce the desired movement of the abrasive member. 
     In still other embodiments, the abrasive  98  is formed of a material that allows the abrasive  98  to remain in constant engagement with the blade tire  86 . In a further embodiment, the abrasive  98  is coupled to the band saw  10  in an engaged position against the blade tire  86  such that user actuation of the debris removal system is not required. For example, a scraper could be positioned immediately adjacent the blade tire  86  or in constant contact with the blade tire  86  to continuously remove debris. 
     In the embodiment of  FIGS. 1-5 , the abrasive  98  engages the blade tire  86  when the debris removal system  94  is actuated. In other embodiments, the abrasive  98  is partially engaged with the blade tire  86  when in a neutral or release position and is able to remove some debris, and when the debris removal system  94  is fully engaged with the blade tire  86 , the abrasive  98  removes all or most of the debris. 
     In other embodiments, the debris removal system is used on a variety of power tools that have moving components affected by debris embedding or attaching to those components. 
     Although particular constructions embodying independent aspects of the present invention have been shown and described, other alternative constructions will become apparent to those skilled in the art and are within the intended scope of the independent aspects of the present invention.