Abstract:
A power tool includes a tool housing defining a cavity and a pocket formed in a wall of the tool housing. A motor is positioned within the cavity, and a trigger mechanism is moveably coupled to the tool housing. A speed selector switch is positioned within the pocket, the speed selector switch including a push-button operable to receive a speed selection and a plurality of speed indicators. The speed selector switch is operable to output a speed signal based on the speed selection, and the speed indicators indicate the speed selection. The power tool further includes a controller operable to receive the speed signal from the speed selector switch, the speed signal indicative of a selected speed, receive an activation signal from the trigger switch, and operate the motor at the selected speed upon receiving the activation signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to U.S. Provisional Application 61/641,754, filed May 2, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to power tools, such as power drills or impact drivers. 
         [0003]    Power tools, such as power drills or impact drivers, have multiple operating speeds. With multi-speed tools it is necessary for the user to be able to switch the operating speed of the tool. 
       SUMMARY 
       [0004]    In one embodiment, the invention provides a power tool includes a tool housing defining a cavity and a pocket formed in a wall of the tool housing. A motor is positioned within the cavity, and a trigger mechanism is moveably coupled to the tool housing. A speed selector switch is positioned within the pocket, the speed selector switch including a push-button operable to receive a speed selection and a plurality of speed indicators. The speed selector switch is operable to output a speed signal based on the speed selection, and the speed indicators indicate the speed selection. The power tool further includes a controller operable to receive the speed signal from the speed selector switch, the speed signal indicative of a selected speed, receive an activation signal from the trigger switch, and operate the motor at the selected speed upon receiving the activation signal. 
         [0005]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a tool according to one embodiment of the invention. 
           [0007]      FIG. 2  is a side view of the tool shown in  FIG. 1  with a portion of a tool housing removed. 
           [0008]      FIG. 3  illustrates a direction switch of the tool shown in  FIG. 1  in a FORWARD position. 
           [0009]      FIG. 4  illustrates the direction switch of the tool shown in  FIG. 1  in a REVERSE position. 
           [0010]      FIG. 5  illustrates the direction switch of the tool shown in  FIG. 1  in a NEUTRAL position. 
           [0011]      FIG. 6  illustrates a speed selector switch of the tool shown in  FIG. 1 . 
           [0012]      FIG. 7  illustrates a block diagram of the speed selector switch shown in  FIG. 6 . 
           [0013]      FIG. 8  is an electrical schematic diagram of the tool shown in  FIG. 1 , and including a controller. 
           [0014]      FIG. 9  is an operational schematic diagram of the tool shown in  FIG. 1 . 
           [0015]      FIG. 10  is a perspective view of the tool shown in  FIG. 1  with the tool housing removed. 
           [0016]      FIG. 11  is a perspective view of the tool shown in  FIG. 1  with a motor and a portion of the tool housing removed. 
       
    
    
       [0017]    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. 
       DETAILED DESCRIPTION 
       [0018]      FIG. 1  is a perspective view of a power tool  100  (e.g., a power drill, an impact driver, a power saw, an angle driver, etc.). The tool  100  includes a tool housing  105  defining a body portion  110  and a handle  115 . The body portion  110  of the tool housing  105  includes a top surface  120 , a bottom surface  125 , side surfaces  130 ,  135 , a front surface  140 , and a rear surface  145 .  FIG. 2  illustrates the tool  100  with a portion of the tool housing  105  removed. The tool housing  105  further includes a wall  150  defining an exterior surface  155  and an interior surface  160  of the housing  105 . The interior surface  160  defines a cavity  162  within the body portion  110 . 
         [0019]    A speed selector switch  165  is disposed between the exterior surface  155  and the interior surface  160  of the wall  150  and within a pocket  170  defined by the wall  150 . In the illustrated embodiment, the pocket  170  is located proximate to the cavity  162 , and the speed selector switch  165  is accessible from the top surface  120  of the body portion  110 . In other embodiments, the speed selector switch  165  is accessible another surface of the housing, such as one of the side surfaces  130 ,  135  or the rear surface  145 . A printed circuit board (PCB)  175  and a motor  180  are located within the cavity  162  of the body portion  110 . The motor  180  is coupled to the interior surface  160  of wall  150  via a motor mount  185 . 
         [0020]    In the illustrated embodiment, the handle  115  extends downwardly from the bottom surface  125  of the body portion  110  such that the tool  100  has a pistol-style grip. A battery receptacle  190  is located at a distal end of the handle  115 , and a trigger mechanism  195  is positioned on the handle  115  proximate the body portion  110 . 
         [0021]    The PCB  175  is electrically coupled to the motor  180  and includes electrical and electronic components that are operable to control the tool  100 . In the illustrated embodiment, the PCB  175  includes a controller  200  ( FIG. 8 ) for controlling operation of the tool  100 . 
         [0022]    The motor  180  is a multi-speed, brushless direct-current (BLDC) motor. As is commonly known, BLDC motors include a stator, a permanent magnet rotor, and an electronic commutator. The electronic commutator typically includes, among other things, a programmable device (e.g., a microcontroller, a digital signal processor, or a similar controller) having a processor and a memory. The programmable device of the BLDC motor uses software stored in the memory to control the electric commutator. The electric commutator then provides the appropriate electrical energy to the stator in order to rotate the permanent magnet rotor at a desired speed. In some embodiments, the controller  200  acts as the programmable device of the motor  180 . In other embodiments, the programmable device is separate from the controller  200 . In other embodiments of the motor  180 , the motor  180  can be a variety of other types of multi-speed or variable-speed motors, including but not limited to, a brush direct-current motor, a stepper motor, a synchronous motor, an induction motor, a vector-driven motor, a switched reluctance motor, and other DC or AC motors. The motor  180  is used to drive a working element  205  ( FIG. 2 ). In the illustrated embodiment, the working element  205  is located on the front surface  140  of the body portion  110 . In the illustrated embodiment the working element  205  is a drill chuck, but other types of tools, such as angle grinders, saws, etc., will use different working elements. 
         [0023]    The battery receptacle  190  receives a battery  210  ( FIG. 8 ), which provides power to the tool  100 . In some embodiments, the battery  210  is a rechargeable lithium-ion battery. In other embodiments, the battery  210  may have a chemistry other than lithium-ion such as, for example, nickel cadmium, nickel metal-hydride, etc. Additionally or alternatively, the battery  210  may be a non-rechargeable battery. In some embodiments, the battery  210  is a power tool battery including a pack housing containing one or more battery cells and a latching mechanism for selectively securing the battery  210  to the battery receptacle  190 . In another embodiment, the battery  210  is mounted externally to the handle  115 . In another embodiment, the battery  210  is mounted below the handle  115 . In another embodiment, an electrical cord provides power to the tool  100 . 
         [0024]    Referring to  FIGS. 2-6 , the trigger mechanism  195  includes a trigger  215 , a direction switch  220 , and an electrical switch  225 . In the illustrated embodiment, the trigger  215  extends partially down a length of the handle  115 ; however, in other embodiments the trigger  215  extends down the entire length of the handle  115  or may be positioned elsewhere on the tool  100 . The trigger  215  is moveably coupled to the handle  115  such that the trigger  215  moves with respect to the tool housing  105 . The trigger  215  includes an interior portion  230  and an exterior portion  235 , which is accessible to the user. The interior portion  230  is coupled to a push rod  240 , which is engageable with the electrical switch  225 . The exterior portion  235  of the trigger  215  moves in a first direction  245  towards the handle  115 , when the trigger  215  is depressed by the user. The exterior portion  235  moves in a second direction  250 , away from the handle  115 , when the trigger  215  is released by the user. When the trigger  215  is depressed by the user, the push rod  240  activates the electrical switch  225 , and when the trigger  215  is released by the user, the electrical switch  225  is deactivated. 
         [0025]    In the illustrated embodiment, the electrical switch  225  is a push-button electrical switch positioned within the handle  115 . The electrical switch  225  includes a push button  255  and electrical contacts. When the push button  255  is activated, such as by the push rod  240 , the electrical contacts are in a CLOSED position. When the electrical contacts are in the CLOSED position, electrical current is supplied from the battery to the motor  180 , via the controller  200 . When the push button  255  is not activated, the electrical contacts are in the OPEN position. When the electrical contacts are in the OPEN position, electrical current is not supplied from the battery to the motor  180 . Although the electrical switch  225  is illustrated as a push-button electrical switch with contacts, other types of electrical switches may be used with the tool  100 . 
         [0026]    The direction switch  220  is located above the trigger  215  and below the body portion  110  of the tool  100 . The direction switch  220  is slidingly coupled to the handle  115 . As shown in  FIGS. 3-5 , the direction switch  220  includes a first side  260  and a second side  265 . The direction switch  220  controls the directional mode of operation of the motor  180  (e.g., FORWARD, REVERSE, and NEUTRAL) by sending a signal, based on the position of the direction switch  220 , to the controller  200 . As shown in  FIG. 3 , when the first side  260  of the direction switch  220  is fully depressed, the direction switch  220  is in a first position. When the direction switch  220  is in the first position, the mode of operation for motor  180  is in the FORWARD direction. As shown in  FIG. 4 , when the second side  265  of the direction switch  220  is fully depressed, the direction switch  220  is in a second position, the second position being opposite the first position. When the direction switch  220  is in the second position, the mode of operation of the motor  180  is in the REVERSE direction. As shown in  FIG. 5 , when the direction switch  220  is in a third position, neither the first side  260  or second side  265  is fully depressed, and the mode of operation of the motor  180  is NEUTRAL. 
         [0027]    As discussed above, the tool  100  includes the speed selector switch  165 , as shown in more detail in  FIGS. 6 and 7 . The speed selector switch  165  is a multi-layer electrical switch including a label layer  270 , a push-button  275 , a printed circuit board layer  280 , and light-emitting diodes (LEDs)  285 ,  290 . The label layer  270  includes speed indicators  295 ,  300 . Speed indicator  295  indicates to the operator that a first speed is selected, and speed indicator  300  indicates to the operator that a second speed is selected. The push-button  275  is an electrical push-button, and in the illustrated embodiment, the push-button  275  is a low-profile pop-switch. In some embodiments, the printed circuit board layer  280  includes a controller having a similar construction as controller  200 . 
         [0028]    In operation, the speed selector switch  165  controls the operating speed of the motor  180 , via the controller  200 , allowing the operator to choose between the first speed and the second speed. When the push-button  275  is pressed, the operating speed of the motor  180  is switched between the first speed and the second speed. The LEDs  285 ,  290  illuminate the speed indicators  295 ,  300 , indicating to the operator the currently selected speed of the motor  180 . When the first speed of the motor  180  is selected, LED light  285  is activated illuminating speed indicator  295 , while LED light  290  is inactive. When the second speed of the motor  180  is selected, LED light  290  is activated illuminating speed indicator  300 , while LED light  285  is inactive. Although the embodiment discussed illustrates only two speeds, it is contemplated that the tool may have three or more speeds. 
         [0029]      FIG. 8  is an electrical schematic of the tool  100  including the controller  200 . The controller  200  is electrically and/or communicatively connected to a variety of modules or components of the tool  100 . For example, the controller  200  is electrically connected to the battery  210 , the motor  180 , the speed selector switch  165 , components of the trigger mechanism  195  (i.e., the electrical switch  225  and the direction switch  220 ), as well as other components of the tool  100 . The controller  200  includes combinations of hardware and software that are operable to, among other things, control the operation of the tool  100 . In some embodiments, the controller  200  includes electrical and electronic components that provide power, operational control, and protection to the components and modules within the controller  200  and tool  100 . For example, the controller  200  includes, among other things, a processor  202  (e.g., a microprocessor, a microcontroller, or another suitable programmable device) and a memory  203 . 
         [0030]    The memory  203  includes, for example, a program storage and a data storage. The program storage and the data storage can include combinations of different types of memory, such as read-only memory (“ROM”), random access memory (“RAM”) (e.g., dynamic RAM [“DRAM”], synchronous DRAM [“SDRAM”], etc.), electrically erasable programmable read-only memory (“EEPROM”), flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processor  202  is connected to the memory  203  and executes software instructions that are capable of being stored in a RAM of the memory  203  (e.g., during execution), a ROM of the memory  203  (e.g., on a generally permanent basis), or another non-transitory computer readable medium such as another memory or a disc. Software included in the implementation of the tool  100  can be stored in the memory  203  of the controller  200 . The software includes, for example, firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The controller  200  is configured to retrieve from memory and execute, among other things, instructions related to the control processes and method described herein. In other embodiments, the controller  200  includes additional, fewer, or different components. 
         [0031]    The controller  200  is electrically coupled to the speed selector switch  165 , the motor  180 , the electrical switch  225  and the direction switch  220  of the trigger mechanism  195 , and the battery  210 , through the battery receptacle  190 . The controller  200  receives signals from the electrical components of the tool  100  and controls operation of the tool  100  according to the received signals. 
         [0032]    In one embodiment of operation, a user selects a first speed or a second speed using the speed selector switch  165 . The speed selector switch  165  sends a first speed signal or a second speed signal to the controller  200 . The user then selects a FORWARD direction, a REVERSE direction, or NEUTRAL using the direction switch  220 . The direction switch  220  sends a direction signal to the controller  200 . Once the user activates the trigger mechanism  195 , the electrical switch  225  of the trigger mechanism  195  sends an activation signal to the controller  200 . The controller operates the motor  180  upon receiving the activation signal, and the motor  180  is operated at the selected speed and selected direction. 
         [0033]      FIG. 9  illustrates an operation  400  of the controller  200 . The controller  200  receives a speed signal from the speed selector switch  165  (Step  405 ) and a direction signal from the direction switch  220  (Step  410 ). The controller  200  determines if the speed signal is a first speed signal (Step  415 ). If the speed signal is the first speed signal, the controller  200  sets the operation speed of the motor  180  to the first speed (Step  420 ). If the speed signal is not the first speed signal, and thus the second speed signal, the controller  200  sets the operation speed of the motor  180  to the second speed (Step  425 ). 
         [0034]    Next, the controller  200  determines if the direction switch  220  is in a neutral position, and thus the controller  200  is receiving a neutral signal (Step  430 ). If the direction switch  220  is in a neutral position, the operation cycles back to Step  405 . If the direction switch  220  is not in the neutral position, the controller  200  determines if the direction switch  220  is in a forward position, and thus the controller  200  is receiving a forward signal (Step  435 ). If the controller  200  determines the direction switch  220  is in the forward position, the controller  200  sets the direction of the motor  180  to the forward position (Step  440 ). If the controller  200  determines the direction switch  220  is not in the forward position, and thus is in the reverse direction, the controller sets the direction of the motor  180  to the reverse position (Step  445 ). 
         [0035]    Once the direction signal is determined, the controller  200  determines if the electrical switch  225  has been activated (Step  450 ). If the controller  200  determines that the electrical switch  225  has not been activated, the operation cycles back to Step  405 . If the controller  200  determines that the electrical switch  225  has been activated, the controller  200  activates the motor  180  according to the selected speed and selected direction (Step  455 ). The operation then cycles back to Step  450 . 
         [0036]    Referring to  FIG. 10 , in the illustrated embodiment, the speed selector switch  165  is located within the pocket  170  proximate to the motor  180  and accessible from the top surface  120  of the body portion  110 . The compact design of the speed selector switch  165  allows it to be placed in the relatively small space above the motor  180 . Further, the lightweight design of the speed selector switch  165  adds little weight to the tool  100 . 
         [0037]    As shown in  FIG. 11 , with the motor  180  removed for viewing purposes, wires  500  for the speed selector switch  165  run along a side of the interior surface  160  of wall  150  and electrically couple the speed selector switch  165  to the PCB  175 . 
         [0038]    Thus, the invention provides, among other things, a power tool including a speed selector switch for selecting an operating speed of the power tool. Various features and advantages of the invention are set forth in the following claims.