Patent Description:
Embodiments described herein provide battery pack powered power tools.

<CIT> shows the preamble of claim <NUM> and describes a method for controlling an electric hand-held power tool having a device housing and a coupling device on the device housing side for securing an auxiliary handle to the device housing.

<CIT> describes a handheld machine tool with a drive motor and a supplementary handle.

<CIT> describes a driven machine tool with a drive unit and a housing with a first gripping section. The machine tool further comprises an additional handle with a second gripping section which can be detachably connected to the housing of the machine tool, and a safety device which is designed to control the drive unit.

<CIT> describes a power tool such as an angle grinder comprises a motor having a shaft disposed within a housing, a gear case and a side handle. The gear case includes a mechanical lock-out member that is moveable from a default position where it prevents the rotor spindle from rotating, to an unlocked position when the ancillary handle is installed on the gear case, allowing the rotor spindle to turn.

<CIT> describes a system includes a power tool and an automatic safety system communicatively coupled to the power tool.

<CIT> describes a portable electric power tool, having a metal housing, at least a region of which is covered with at least one plastic part. To cool that region of the metal housing which gets very warm due to the plastic cover, means are provided which produce air flow supplied from outside and sweeps over the metal housing in the region of the plastic part.

Embodiments described herein provide systems, methods, and devices related to the operation of a power tool, such as a grinder. In some embodiments, the power tool includes one or more impedance sensors that can be used to detect when a user is gripping one or more handles or surfaces of the power tool. The power tool must detect the presence of a user's hand on each of a first handle and a second handle of the power tool to permit operation of the power tool. In other embodiments, only one hand needs to be detected before the power tool is permitted to be operated. A controller of the power tool is configured to distinguish between a user's hand (i.e., a human hand) and another object (e.g., an inanimate object) based on output signals from the one or more impedance sensors. For example, the power tool <NUM> is more resistant to false activations from liquids (e.g., water), dirt, debris, etc..

Embodiments described herein provide a band saw including a housing and a motor located within the housing. The band saw includes a first handle and a second handle. The first handle includes a first trigger configured to be actuated by a user. A first hand of the user may be detected on the first handle based on actuation or de-actuation of the first trigger. The second handle includes a touch sensor (e.g., a capacitive touch sensor, an inductive touch sensor). The touch sensor is configured to detect a second hand of the user on the second handle. The band saw includes a controller operable to control operation of the motor and monitor for the actuation state of both the first trigger and the touch sensor. When the touch sensor is in an actuated state and is followed by the first trigger being in an actuated state, the controller drives the motor. When the first trigger is in an actuated state and is followed by the touch sensor being in an actuated state, the controller prohibits operation of the motor.

Power tools described herein include a housing, a motor situated within the housing, a first handle, a second handle, and a controller. The first handle includes a user input configured to be actuated by a first hand of a user. The second handle includes a touch sensor configured to detect a second hand of the user on the second handle. The controller is connected to the motor, the user input, and the touch sensor. The controller is configured to determine whether the user input is actuated, determine whether the second hand of the user is on the second handle, control, in response to both the user input being actuated and the second hand of the user being on the second handle, the motor to drive the motor, and prohibit, in response to the user input being actuated and the second hand of the user not being on the second handle, operation of the motor. The controller is further configured to determine whether the user input is actuated after determining whether the second hand of the user is on the second handle and prohibit, in response to the user input being actuated before the second hand of the user is on the second handle, operation of the motor.

In some aspects, the touch sensor is an impedance sensor including a surface, a transmitter configured to provide a load sine wave to the surface, and a receiver configured to receive a current response of the load sine wave.

In some aspects, the controller is configured to determine whether the second hand of the user is on the second handle based on a change in the current response of the load sine wave.

In some aspects, the surface is curved to interface with the second handle.

In some aspects, the touch sensor is a capacitive sensor.

In some aspects, the controller is further configured to enter, in response to the user input not being actuated and the second hand of the user not being on the second handle, a sleep mode.

In some aspects, a first portion of the housing is composed of a metallic material, and the first portion is configured as a heat sink.

Methods described herein include determining, with a controller, whether a user input is actuated, the user input associated with a first handle, and determining, with the controller and based on a signal from a touch sensor integrated in a second handle, whether a hand of a user is on the second handle. The method includes controlling, with the controller and in response to both the user input being actuated and the hand of the user being on the second handle, a motor to drive the motor. The method includes prohibiting, with the controller and in response to the user input being actuated and the second hand of the user not being on the second handle, operation of the motor. The method includes determining, with the controller, whether the user input is actuated after determining whether the hand of the user is on the second handle, and prohibiting, with the controller and in response to the user input being actuated before the hand of the user is on the second handle, operation of the motor.

In some aspects, the method includes providing, with a transmitter of the touch sensor, a load since wave to a metal plate, and receiving, with a receiver of the touch sensor, a current response of the load sine wave.

In some aspects, the method includes determining, with the controller, whether the hand of the user is on the second handle based on a change in the current response of the load sine wave.

In some aspects, the method includes entering, with the controller and in response to the user input not being actuated and the hand of the user not being on the second handle, a sleep mode.

Power tools described herein include a housing, a motor situated within the housing, a first handle, a second handle, an indicator, and a controller. The first handle includes a user input configured to be actuated by a first hand of a user. The second handle includes a touch sensor configured to detect a second hand of the user on the second handle. The indicator is configured to provide an output. The controller is connected to the motor, the indicator, the user input, and the touch sensor. The controller is configured to determine whether the user input is actuated, determine whether the second hand of the user is on the second handle, and drive, in response to both the user input being actuated and the second hand of the user being on the second handle, the motor. The controller, in response to the user input being actuated and the second hand of the user not being on the second handle, is configured to prohibit operation of the motor and control the indicator to provide the output.

In some aspects, the controller is configured to determine, after determining that the user input is operated, that the second hand of the user is on the second handle, and continue, in response to the second hand of the user being on the second handle after determining that the user input is operated, prohibiting operation of the motor.

In some aspects, the controller is configured to determine, after prohibiting operation of the motor, whether the user input is actuated, and disable, in response to the user input not being actuated and the second hand of the user not being on the second handle, the indicator.

Before any embodiments are explained in detail, it is to be understood that the embodiments are not limited in application to the details of the configurations and arrangements of components set forth in the following description or illustrated in the accompanying drawings. The embodiments are capable of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof are meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Unless the context of their usage unambiguously indicates otherwise, the articles "a," "an," and "the" should not be interpreted as meaning "one" or "only one. " Rather these articles should be interpreted as meaning "at least one" or "one or more. " Likewise, when the terms "the" or "said" are used to refer to a noun previously introduced by the indefinite article "a" or "an," "the" and "said" mean "at least one" or "one or more" unless the usage unambiguously indicates otherwise.

In addition, it should be understood that embodiments may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic-based aspects may be implemented in software (e.g., stored on non-transitory computer-readable medium) executable by one or more processing units, such as a microprocessor and/or application specific integrated circuits ("ASICs"). As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components, may be utilized to implement the embodiments. For example, "servers," "computing devices," "controllers," "processors," etc., described in the specification can include one or more processing units, one or more computer-readable medium modules, one or more input/output interfaces, and various connections (e.g., a system bus) connecting the components.

Relative terminology, such as, for example, "about," "approximately," "substantially," etc., used in connection with a quantity or condition would be understood by those of ordinary skill to be inclusive of the stated value and has the meaning dictated by the context (e.g., the term includes at least the degree of error associated with the measurement accuracy, tolerances [e.g., manufacturing, assembly, use, etc.] associated with the particular value, etc.). Such terminology should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression "from about <NUM> to about <NUM>" also discloses the range "from <NUM> to <NUM>". The relative terminology may refer to plus or minus a percentage (e.g., <NUM>%, <NUM>%, <NUM>%) of an indicated value.

It should be understood that although certain drawings illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. Functionality described herein as being performed by one component may be performed by multiple components in a distributed manner. Likewise, functionality performed by multiple components may be consolidated and performed by a single component. In some embodiments, the illustrated components may be combined or divided into separate software, firmware and/or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links. Similarly, a component described as performing particular functionality may also perform additional functionality not described herein. For example, a device or structure that is "configured" in a certain way is configured in at least that way but may also be configured in ways that are not explicitly listed.

Accordingly, in the claims, if an apparatus, method, or system is claimed, for example, as including a controller, control unit, electronic processor, computing device, logic element, module, memory module, communication channel or network, or other element configured in a certain manner, for example, to perform multiple functions, the claim or claim element should be interpreted as meaning one or more of such elements where any one of the one or more elements is configured as claimed, for example, to make any one or more of the recited multiple functions, such that the one or more elements, as a set, perform the multiple functions collectively.

Other aspects of the embodiments will become apparent by consideration of the detailed description and accompanying drawings.

<FIG>, <FIG>, and <FIG> illustrate a power tool <NUM>. In some embodiments, the power tool <NUM> is a grinder. Although a grinder is illustrated, the power tool <NUM> can be a variety of other types of power tools, such as drilling power tools, fastening power tools, sawing power tools, cutting power tools, power tool battery packs, power supplies, lighting devices, etc. For example, the power tools can include motorized power tools (e.g., a drill, an impact driver, an impact wrench <NUM>, a rotary hammer, a hammer drill, a saw [e.g., a circular saw, a cut-off saw <NUM>, a reciprocating saw, a miter saw, a table saw <NUM>, etc.], a core drill <NUM>, a breaker <NUM>, a demolition hammer, a compressor <NUM>, a pump, etc.), outdoor tools (e.g., a chain saw <NUM>, a string hammer, a hedge trimmer, a blower, a lawn mower, etc.), drain cleaning and plumbing tools, construction tools, concrete tools, other motorized devices (e.g., vehicles, utility carts, wheeled and/or self-propelled tools, etc.), etc., non-motorized electrical devices (e.g., a power supply <NUM>, a light <NUM>, a battery pack charger <NUM>, a generator, etc.), and an adapter that is configured to be positioned between a power tool and a battery pack, such as adapter <NUM> (see <FIG>).

The power tool <NUM> includes a main tool housing <NUM>, a first handle <NUM> that extends along the main tool housing <NUM>, and a second handle <NUM> that extends transversely in an outward direction from the main tool housing <NUM>. A motor <NUM> (see <FIG>) is located within the main tool housing <NUM>. An output shaft <NUM> is coupleable to a tool holder <NUM> that may be configured to receive an accessory, such as a cutting tool, a grinding disc, a rotary burr, a sanding disc, etc. Various types of accessories may be interchangeably attached to the tool holder <NUM> and may be designed with different characteristics to perform different types of operations. For example, the accessory may be made of a material and have dimensions suitable for performing a specific type of task. The characteristics of an accessory may affect the performance of the power tool <NUM> or may impose constraints on operation of the power tool. For example, different accessory types may be configured to work at different rotational speeds or applied torques depending on the characteristics of the accessory and the task to be performed. During operation of the power tool <NUM>, the motor <NUM> and the output shaft <NUM> may be controlled to rotate at a wide range of speeds.

Due to the wide range of speeds, in some embodiments, the power tool <NUM> may include a guard <NUM> to protect a user or another object in the surrounding environment from the different accessory types that may be attached to the tool holder <NUM>. In some embodiments, the guard <NUM> prevents a user from contacting the accessory. In some embodiments, the guard <NUM> provides protection against, for example, sparks.

In some embodiments, the first handle <NUM> may include or define a battery pack receptacle <NUM>, which is positioned on an end of the first handle <NUM> opposite the main tool housing <NUM>. The battery pack receptacle <NUM> is configured to selectively, mechanically and electrically connect to a rechargeable battery pack (i.e., a power supply) for powering the motor <NUM>. The battery pack is insertable into or attachable to the battery pack receptacle <NUM>. The battery pack may include any of a number of different nominal voltages (e.g., 12V, 18V, 24V, 36V,40V, 48V, 72V, etc.), and may be configured having any of a number of different chemistries (e.g., lithium-ion, nickel-cadmium, etc.). In some embodiments, the motor <NUM> may be powered by a remote power source (e.g., an AC electrical outlet) through a power cord and a power interface of the power tool <NUM>. The first handle <NUM> further includes control electronics for the power tool <NUM>.

The second handle <NUM> may allow a user to better control the operation of the power tool <NUM>. The first handle <NUM> and/or the second handle <NUM> include one or more sensors to detect different operational characteristics and/or user characteristics (e.g., operator presence, grip pressure, etc.). For example, the first handle <NUM> includes a first sensor <NUM> for detecting the presence of a user's hand on the first handle <NUM>, and the second handle <NUM> includes a second sensor <NUM> for detecting the presence of a user's second hand on the second handle <NUM>. In some embodiments, the sensors <NUM>, <NUM> are impedance sensors that detect the presence of a user's hand on the handles <NUM>, <NUM>. In other embodiments, the sensors <NUM>, <NUM> are capacitive sensors that detect the presence of a user's hand on the handles <NUM>, <NUM>. Signals from the sensors <NUM>, <NUM> are provided to the power tool <NUM>'s main control system, and the operation of the motor <NUM> may be controlled based on the signals (e.g., enabling or disabling the motor <NUM>, modifying a torque limit, modifying a speed limit, etc.).

As illustrated in <FIG>, the power tool <NUM> also includes an input device or user input <NUM> (e.g., a button, a switch, a lever, a trigger, etc.) for controlling the power tool <NUM>. As also illustrated in <FIG>, the grinder can include additional sensors <NUM>, <NUM> on an under or bottom side of the first handle <NUM> and/or the second handle <NUM>. In some embodiments, the sensors <NUM>, <NUM> shown in <FIG> replace the sensors <NUM>, <NUM> shown in <FIG> and <FIG>. In other embodiments, sensors <NUM>, and <NUM> are provided on both the upper or top side (<FIG> and <FIG>) and the under or bottom side (<FIG>).

Although the sensors <NUM>, <NUM> are illustrated only with respect to the first handle <NUM> and the second handle <NUM>, the sensors <NUM>, <NUM> can also be located at different locations on the power tool <NUM> (e.g., the main tool housing <NUM>).

<FIG> illustrates a side section view of the power tool <NUM>. In some embodiments, a control printed circuit board <NUM> is located within the first handle <NUM>. In some embodiments, the sensors <NUM>, <NUM> are located within the first handle <NUM> itself or within a space defined by the first handle <NUM>. The output shaft <NUM> protrudes downwards away from the housing <NUM>, towards a potential workpiece. In some embodiments, an accessory (e.g., a grinder blade) may be attached to the output shaft <NUM>. Because an accessory, such as a grinder blade, is potentially hazardous to the user and the area surrounding the grinder, the guard <NUM> is also attached to the power tool <NUM> and protrudes downward toward a workpiece, and extends around a grinder blade. This provides protection from the blade and any potential debris that is produced during operation. In some embodiments, the motor <NUM> is located between the output shaft <NUM> and the battery pack receptacle <NUM>.

<FIG> illustrates a control system for the power tool <NUM>. The control system includes a controller <NUM>. The controller <NUM> is electrically and/or communicatively connected to a variety of modules or components of the power tool <NUM>. For example, the illustrated controller <NUM> is electrically connected to the motor <NUM>, a battery pack interface <NUM> (e.g., battery pack receptacle <NUM>), an input switch <NUM> (connected to an input <NUM> [e.g., input device <NUM>]), one or more sensors or sensing circuits <NUM> (e.g., the sensors <NUM>, <NUM>), one or more indicators <NUM>, a user input module <NUM>, a power input module <NUM>, and a switching module <NUM> (e.g., including a plurality of switching FETs). The controller <NUM> includes combinations of hardware and software that are operable to, among other things, control the operation of the power tool <NUM>, monitor the operation of the power tool <NUM>, activate the one or more indicators <NUM> (e.g., an LED), etc..

The controller <NUM> includes a plurality of electrical and electronic components that provide power, operational control, and protection to the components and modules within the controller <NUM> and/or the power tool <NUM>. For example, the controller <NUM> includes, among other things, a processing unit <NUM> (e.g., a microprocessor, a microcontroller, an electronic processor, an electronic controller, or another suitable programmable device), a memory <NUM>, input units <NUM>, and output units <NUM>. The processing unit <NUM> includes, among other things, a control unit <NUM>, an arithmetic logic unit ("ALU") <NUM>, and a plurality of registers <NUM>, and is implemented using a known computer architecture (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit <NUM>, the memory <NUM>, the input units <NUM>, and the output units <NUM>, as well as the various modules or circuits connected to the controller <NUM> are connected by one or more control and/or data buses (e.g., common bus <NUM>). The use of one or more control and/or data buses for the interconnection between and communication among the various modules, circuits, and components would be known to a person skilled in the art in view of the invention described herein.

The memory <NUM> is a non-transitory computer readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area can include combinations of different types of memory, such as a ROM, a RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processing unit <NUM> is connected to the memory <NUM> and executes software instructions that are capable of being stored in a RAM of the memory <NUM> (e.g., during execution), a ROM of the memory <NUM> (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 power tool <NUM> can be stored in the memory <NUM> of the controller <NUM>. 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 <NUM> is configured to retrieve from the memory <NUM> and execute, among other things, instructions related to the control processes and methods described herein. In other constructions, the controller <NUM> includes additional, fewer, or different components.

The motor <NUM> includes a rotor and a stator that surrounds the rotor, or a stator and a rotor that surrounds the stator. In some embodiments, the motor <NUM> is a brushless direct current ("BLDC") motor in which the rotor is a permanent magnet rotor, and the stator includes coil windings that are selectively energized to drive the rotor. In other embodiments, the motor is a brushed motor. The stator is supported within the main tool housing <NUM> and remains stationary relative to the main tool housing <NUM> during operation of the power tool <NUM>. The rotor is rotatably fixed to a rotor shaft and configured to rotate with the rotor shaft, relative to the stator, about a motor axis. A portion of the rotor shaft is associated with or corresponds to the output shaft <NUM> extending from the main tool housing <NUM>.

The battery pack interface <NUM> includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) configured to and operable for interfacing (e.g., mechanically, electrically, and communicatively connecting) the power tool <NUM> with a battery pack. For example, power provided by the battery pack to the power tool <NUM> is provided through the battery pack interface <NUM> to the power input module <NUM>. The power input module <NUM> includes combinations of active and passive components to regulate or control the power received from the battery pack prior to power being provided to the controller <NUM>. The battery pack interface <NUM> also supplies power to the switching module <NUM> to provide power to the motor <NUM>. The battery pack interface <NUM> also includes, for example, a communication line <NUM> for providing a communication line or link between the controller <NUM> and the battery pack.

The indicators <NUM> include, for example, one or more light-emitting diodes ("LEDs"). The indicators <NUM> can be configured to display conditions of, or information associated with, the power tool <NUM>. For example, the indicators <NUM> are configured to indicate measured electrical characteristics of the power tool <NUM>, the status of the power tool <NUM>, etc. The user input module <NUM> is operably coupled to the controller <NUM> to, for example, select a forward mode of operation or a reverse mode of operation, a torque and/or speed setting for the power tool <NUM> (e.g., using torque and/or speed switches), etc. In some embodiments, the user input module <NUM> includes a combination of digital and analog input or output devices required to achieve a desired level of operation for the power tool <NUM>, such as one or more knobs, one or more dials, one or more switches, one or more buttons, etc..

The controller <NUM> is configured to determine whether a fault condition of the power tool <NUM> is present and generate one or more control signals related to the fault condition. For example, the sensing circuits <NUM> include one or more current sensors, one or more speed sensors, one or more Hall Effect sensors, one or more temperature sensors, an accelerometer, a gyroscope, an inertial measurement unit ["IMU"], one or more pressure sensors, one or more object presence sensors, one or more impedance sensors, one or more touch sensors (e.g., capacitive sensors), etc. The controller <NUM> calculates or includes, within memory <NUM>, predetermined operational threshold values and limits for operation of the power tool <NUM>. For example, when a potential thermal failure (e.g., of a FET, the motor <NUM>, etc.) is detected or predicted by the controller <NUM>, power to the motor <NUM> can be limited or interrupted until the potential for thermal failure is reduced. If the controller <NUM> detects one or more such fault conditions of the power tool <NUM> or determines that a fault condition of the power tool <NUM> no longer exists, the controller <NUM> is configured to provide information and/or control signals to another component of the power tool <NUM> (e.g. the battery pack interface <NUM>, the indicators <NUM>, etc.).

<FIG> illustrate a power tool <NUM> (e.g., a band saw) including a frame or housing <NUM> supporting a motor <NUM> and a gear box <NUM> (see <FIG>). In the illustrated example of the power tool <NUM>, the motor <NUM> is configured as a DC brushless motor, and the power tool <NUM> is configured to receive a removable and rechargeable battery pack <NUM> for supplying power to the power tool <NUM>. <FIG> and <FIG> provide different example locations of the battery pack <NUM> connected to the power tool <NUM>. The motor <NUM> is drivingly connected to a drive assembly through a gear box <NUM>. The motor <NUM>, the drive assembly, and the gear box <NUM> are supported by the housing <NUM>. The drive assembly may include any of a number of bearing arrangements and different gear train arrangements configured to provide various speed and torque outputs. The motor <NUM> and the drive assembly are operable to drive a continuous band saw blade <NUM> to cut a workpiece.

The housing <NUM> includes a primary handle <NUM> with a primary switch or primary trigger <NUM> to provide power to the power tool <NUM>. The primary trigger <NUM> is disposed adjacent a gripping portion <NUM> of the primary handle <NUM> where a user grasps the power tool <NUM>. In the example of <FIG>, the battery pack <NUM> is supported by the primary handle <NUM> and is an <NUM>-volt power tool battery pack <NUM>. In other embodiments, such as that shown in the example of <FIG>, the battery pack <NUM> may be supported on the housing <NUM>. The primary trigger <NUM> is operable to control operation of the motor <NUM>. Specifically, the battery pack <NUM> selectively supplies power to the motor <NUM> based on an actuation of the primary trigger <NUM>.

The housing <NUM> of the power tool <NUM> also includes a deck <NUM> and a guard <NUM> coupled to the deck <NUM>. A combination of the deck <NUM> and the guard <NUM> defines an opening or cavity <NUM> (e.g., a U-shaped cavity). The guard <NUM> includes a lip (not shown) that provides a recessed area in which the band saw blade <NUM> is positioned. The guard <NUM> substantially covers the band saw blade <NUM> when the blade <NUM> is in a shielded position (i.e., when the blade <NUM> is outside of a cut zone <NUM>). The cavity <NUM> enables the band saw blade <NUM> to be in an exposed position (i.e., when the blade <NUM> passes through the cut zone <NUM>). In the exposed position, the blade <NUM> is fully exposed and unobstructed by the guard <NUM>, allowing workpieces to be cut when entering the cut zone <NUM>.

The power tool <NUM> also includes a secondary handle <NUM> with a secondary trigger or secondary switch <NUM>, shown in detail in <FIG>. The secondary switch <NUM> is adjacent to a secondary gripping portion <NUM>. The secondary switch <NUM> may be, for example, a touch sensor configured to detect whether a user is gripping the secondary handle <NUM>, as described below in more detail. In some embodiments, the secondary switch <NUM> is an inductive sensor. In other embodiments, the secondary switch <NUM> is a capacitive sensor. The capacitive sensor may include a sensing probe formed of unshielded wire routed from the controller <NUM> (see <FIG>) and coiled in the secondary handle <NUM> to detect the presence of an operator's hand. In some instances, the power tool <NUM> includes a reference capacitance (e.g., mounted on a printed circuit board) that can be used to mitigate or eliminate measurement drift due to common-mode environmental factors. In some instances, the capacitive sensor may also include a reference probe formed of a shielded copper pour configured to detect capacitance levels due to environmental conditions. In some embodiments, two or more capacitive sensors are integrated in the secondary handle <NUM> to detect an operator's hand.

In some instances, the secondary handle <NUM> includes a projection <NUM> configured to support a workpiece to be cut by the power tool <NUM>. The secondary handle <NUM> may include an adjusting knob <NUM> configured such that rotation of the adjusting knob adjusts a position of the secondary handle <NUM>, the projection <NUM>, or a combination thereof. In some embodiments, the secondary handle <NUM> is removably connected to the housing <NUM> via one or more fasteners <NUM> (e.g., screws). In some embodiments, as shown in <FIG> and <FIG>, the secondary handle <NUM> is configured as a D-handle. In other embodiments, the secondary handle <NUM> may be configured as a pommel, as shown in <FIG>.

<FIG> illustrates a housing portion <NUM> of the housing <NUM> of the power tool <NUM>. In the illustrated embodiment, the housing portion <NUM> of the housing <NUM> is made of a metallic material. In some embodiments, the housing portion <NUM> of the housing <NUM> is referred to as a deck of the power tool <NUM>. The housing portion <NUM> is configured to function as a heat sink for the power tool <NUM>. As such, an external portion of the housing <NUM> is configured as a heatsink (e.g., rather than having a heatsink positioned within the housing <NUM>). Because the performance of a heatsink is a function of the thermal mass and surface area of the heatsink, forming an external portion of the housing <NUM> into a heatsink increases both the thermal mass of the heatsink and the surface area available to dissipate generated heat. The increased thermal mass and surface area of the housing portion <NUM> acting as a heat sink increases the heatsinking performance of the power tool <NUM>. Using an external portion of the housing <NUM> as a heatsink also functions to reduce overall material cost, size, and weight of the power tool <NUM>.

The housing portion <NUM> can include a recessed portion <NUM> configured to receive a printed circuit board ("PCB") <NUM>. In some embodiments, a thermally conductive pad can be placed between the housing portion <NUM> and the PCB <NUM>. In some embodiments, the PCB <NUM> can be potted into the recessed portion <NUM> using a potting compound to improve ingress protection (e.g., water intrusion). In some embodiments, the housing portion <NUM> is machined. For example, mounting holes <NUM>, <NUM> can be machined into the housing portion <NUM> for assembling the power tool <NUM>. In some embodiments, one or more threaded mounting holes can be machined into the housing portion <NUM> for securing the PCB <NUM> to the housing portion <NUM> and/or for assembling the power tool <NUM>. In some embodiments, the housing portion <NUM> is first cast and then machined in a fashion similar to that described above.

<FIG> illustrates a controller <NUM> for the power tool <NUM>. The controller <NUM> is electrically and/or communicatively connected to a variety of modules or component of the power tool <NUM>. For example, the illustrated controller <NUM> is connected to indicators <NUM>, sensors <NUM> (which may include, for example, a pressure sensor, a speed sensor, a current sensor, a voltage sensor, a position sensor, etc.), the primary trigger <NUM>, a trigger switch <NUM>, a switching network <NUM>, a power input unit <NUM>, the motor418, and the secondary switch <NUM>. In some embodiments, the sensors <NUM> include one or more capacitive sensors and/or one or more impedance sensors (e.g., an impedance sensing integrated circuit). A capacitance sensor or an impedance sensor can be used to detect, for example, a type of material that the power tool <NUM> is cutting, an accessory (e.g., a blade, a handle, etc.) connected to the power tool <NUM>, etc. Such sensors would not require direct contact with rotating portions of the power tool <NUM> to detect the type of material being cut, the attached accessory, etc. In some embodiments, the secondary switch <NUM> can be implemented using an impedance sensor. In some embodiments, the material being cut can have its own distinct electrical characteristics (e.g., capacitance, impedance, etc.). As a result, the material being cut can affect a capacitance or impedance of an accessory being used to make the cut (e.g., a saw blade). Such variations or changes in capacitance or impedance can be used to identify the material that is being cut. For example, cutting a wooden material will have one effect on capacitance or impedance of the accessory, and human flesh will have a different effect on capacitance or impedance of the accessory. Depending on the detected type of material, the power tool <NUM> can be controlled accordingly (e.g., shut down).

The controller <NUM> includes a plurality of electrical and electronic components that provide power, operational control, and protection to the components and modules within the controller <NUM> and/or power tool <NUM>. For example, the controller <NUM> includes, among other things, a processing unit <NUM> (e.g., a microprocessor, an electronic processor, an electronic controller, a microcontroller, or another suitable programmable device), a memory <NUM>, input units <NUM>, and output units <NUM>. The processing unit <NUM> includes, among other things, a control unit <NUM>, an arithmetic logic unit ("ALU") <NUM>, and a plurality of registers <NUM> (shown as a group of registers in <FIG>), and is implemented using a known computer architecture (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit <NUM>, the memory <NUM>, the input units <NUM>, and the output units <NUM>, as well as the various modules or circuits connected to the controller <NUM> are connected by one or more control and/or data buses (e.g., common bus <NUM>). The control and/or data buses are shown generally in <FIG> for illustrative purposes. The use of one or more control and/or data buses for the interconnection between and communication among the various modules and components would be known to a person skilled in the art in view of the embodiments described herein.

The memory <NUM> is a non-transitory computer readable medium and includes, for example, a program storage area and data storage area. The program storage area and the data storage area can include combinations of different types of memory, such as a ROM, a RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processing unit <NUM> is connected to the memory <NUM> and executes software instruction that are capable of being stored in a RAM of the memory <NUM> (e.g., during execution), a ROM of the memory <NUM> (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 power tool <NUM> can be stored in the memory <NUM> of the controller <NUM>. 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 <NUM> is configured to retrieve from the memory <NUM> and execute, among other things, instructions related to the control processes and methods described herein. In other embodiments, the controller <NUM> includes additional, fewer, or different components.

A battery pack interface <NUM> is connected to the controller <NUM> and couples to the battery pack <NUM>. The battery pack interface <NUM> includes a combination of mechanical (e.g., a battery pack receiving portion) and electrical components configured to and operable for interfacing (e.g., mechanically, electrically, and communicatively connecting) the power tool <NUM> with the battery pack <NUM>. The battery pack interface <NUM> is coupled to power input unit <NUM>. The battery pack interface <NUM> transmits the power received from the battery pack <NUM> to the power input unit <NUM>. The power input unit <NUM> includes active and/or passive components (e.g., voltage step-down controllers, voltage converters, rectifiers, filters, etc.) to regulate or control the power received through the battery pack interface <NUM> and to controller <NUM>.

The controller <NUM> is configured to drive the motor <NUM> in response to a user's actuation of the primary trigger <NUM> (e.g., when operation of the motor <NUM> is permitted). For example, depression of the primary trigger <NUM> actuates or activates a trigger switch <NUM>, which outputs a signal to the controller <NUM> to drive the motor <NUM>, and therefore the blade <NUM>. In some embodiments, the controller <NUM> is configured to control the switching network <NUM> (e.g., a FET switching bridge) to drive the motor <NUM>. For example, the switching network <NUM> may include a plurality of high side switching elements (e.g., FETs) and a plurality of low side switching elements (e.g., FETs). The controller <NUM> may control each of the plurality of high side switching elements and the plurality of low side switching elements to drive each phase of the motor <NUM>. For example, the power switching network <NUM> may also be controlled to more quickly deaccelerate or brake the motor <NUM>.

The indicators <NUM> are also coupled to the controller <NUM> and receive control signals from the controller <NUM> to turn on and off or otherwise convey information based on different states of the power tool <NUM>. The indicators <NUM> include, for example, one or more light-emitting diodes (LEDs), or a display screen. The indicators <NUM> can be configured to display conditions of, or information associated with, the power tool <NUM>. For example, the indicators <NUM> can display information relating to whether operation of the power tool <NUM> is permitted based on signals from the secondary switch <NUM>. In addition to or in place of visual indicators, the indicators <NUM> may also include a speaker or a tactile feedback mechanism to convey information to a user through audible or tactile outputs.

<FIG> illustrates a sensor <NUM> included in the sensors <NUM> of the power tool <NUM>, or sensors <NUM> of the power tool <NUM>. The sensor <NUM> is, for example, an impedance sensor <NUM>. The impedance sensor <NUM> includes a surface <NUM> that can be contacted by a user or an object external to the power tool <NUM>, <NUM>. The impedance sensor <NUM> also includes a transmitter <NUM>, a receiver <NUM>, an output interface <NUM>, and produces an output signal <NUM> that is received by the controller <NUM>, <NUM>. The output signal <NUM> can, for example, provide an indication or whether a user's hand has been detected. In some embodiments, the output signal <NUM> is provided to the controller <NUM>, <NUM> and the controller <NUM>, <NUM> is configured to determine whether a user's hand has been detected.

The transmitter <NUM> provides a current (e.g., a load sine wave) to the surface <NUM>. The receiver <NUM> receives a current response of the load. A change in the current (e.g., in phase and modulus) can be sensed. The current response is converted to a voltage <NUM> and then demodulated into an in-phase component and a quadrature component, as shown in <FIG>. With reference to <FIG>, a sensed or detected impedance <NUM> includes the in-phase component and the quadrature component. The in-phase component corresponds to a resistive component <NUM> of the detected impedance <NUM>. The quadrature component corresponds to a reactive component <NUM> of the detected impedance <NUM>. In some embodiments, the frequency of the sine wave from the transmitter <NUM> is between <NUM> kilo-Hertz ("kHz") and <NUM>. Based on the changes in the resistive and reactive components of the detected impedance <NUM>, when implemented in the power tool <NUM>, the controller <NUM> is configured to determine whether a user is gripping, for example, the first handle <NUM> and/or the second handle <NUM>. When implemented in the power tool <NUM>, the controller <NUM> is configured to determine whether a user is gripping the primary trigger <NUM> and/or the secondary switch <NUM> based on the changes in the resistive and reactive components of the detected impedance <NUM>. In some embodiments, the power tool <NUM>, <NUM> is configured to distinguish between, for example, a human hand gripping the power tool <NUM>, <NUM> and an inanimate object that may be contacting the power tool <NUM>, <NUM>.

<FIG> illustrates an example of the surface <NUM> that can be contacted by a user or an object external to the power tool <NUM>, <NUM>. The surface <NUM> may be composed of a conductive material such as aluminum. In the example of <FIG>, the surface <NUM> is curved to match a shape of and interface with the primary handle <NUM> or the secondary handle <NUM> of the power tool <NUM>.

With reference to the power tool <NUM>, in some instances, the secondary switch <NUM> operates as a safety mechanism of the power tool <NUM>. For example, the controller <NUM> may prohibit operation of the motor <NUM> unless the secondary switch <NUM> is actuated. <FIG> provides a method <NUM> for allowing use of the power tool <NUM>, <NUM>. While described as being performed by the controller <NUM>, the method <NUM> may be performed by the controller <NUM>. At block <NUM>, the controller <NUM> prohibits operation of the motor <NUM>. For example, when the power tool <NUM> is not held by a user, the controller <NUM> defaults to prohibiting operation of the power tool <NUM>. When operation of the power tool <NUM> is prohibited, the controller <NUM>, for example, ignores any signals from the primary trigger <NUM>.

At block <NUM>, the controller <NUM> determines whether a user's hand is on the secondary switch <NUM>. For example, the controller <NUM> determines whether a signal from the touch sensor indicates whether a user's hand is on the secondary switch <NUM>. When a user's hand is not on the secondary switch <NUM> ("NO" at block <NUM>), the controller <NUM> returns to block <NUM> and continues to prohibit operation of the power tool <NUM>. For example, a user may grab the gripping portion <NUM> of the primary handle <NUM>, but does not grab the secondary handle <NUM>. As the secondary handle <NUM> is not gripped, the controller <NUM> can ignore any actuation of the primary trigger <NUM>. When a user's hand is on the secondary switch <NUM> ("YES" at block <NUM>), the controller <NUM> proceeds to block <NUM> and permits operation of the power tool <NUM>.

In some implementations, the controller <NUM> only permits operation of the power tool <NUM> when the secondary switch <NUM> is actuated before the primary trigger <NUM>. For example, if the primary trigger <NUM> is actuated first, and the secondary switch <NUM> is actuated subsequent to the primary trigger <NUM>, the controller <NUM> continues to prohibit operation of the power tool <NUM>.

<FIG> illustrates a method <NUM> for allowing use of the power tool <NUM>, <NUM>. While described as being performed by the controller <NUM>, the method <NUM> may be performed by the controller <NUM>.

When a user indicates an intention to use the power tool <NUM>, the power tool <NUM> is configured to detect, for example, a pick-up of the power tool <NUM> (e.g., by the controller <NUM> using an acceleration sensor), but the power tool <NUM> is prohibited from operating (at block <NUM>). The method <NUM> then includes the controller <NUM> being configured to determine if the user's first hand is detected on the first handle <NUM> (at block <NUM>). In some embodiments, the detection of the user's first hand is detected using the first sensor <NUM>, such as the impedance sensor <NUM>. In other embodiments, determining if the user's first hand is detected is based on an actuation of the input device <NUM>. If the first hand is not detected on the first handle <NUM>, the user is prohibited from using the power tool <NUM>. If the user's first hand is detected, the method <NUM> then includes the controller <NUM> being configured to determine if the user's second hand is detected on the second handle <NUM> (at block <NUM>). In some embodiments, the detection of the user's second hand is detected using the second sensor <NUM>, such as the impedance sensor <NUM>.

If the second hand is not detected on the second handle <NUM>, the user is prohibited from using the power tool <NUM>. If the user's second hand is detected on the second handle <NUM>, the controller <NUM> is configured to allow operation of the power tool <NUM> (at block <NUM>). In some embodiments, only one of the user's hands needs to be detected for the power tool <NUM> to be allowed to operate (e.g., only detecting a user's hand with one of the sensors <NUM>, <NUM>). In some embodiments, a particular sequence of detections are used by the controller <NUM> to allow operation of the power tool <NUM>. For example, the first handle <NUM> must be gripped first (as detected by the first sensor <NUM>) and then the second handle <NUM> must be gripped (as detected by the second sensor <NUM>). In some embodiments, the second handle <NUM> must be gripped first (as detected by the second sensor <NUM>) and then the first handle <NUM> must be gripped (as detected by the first sensor <NUM>). In some embodiments, the first sensor <NUM> and second sensor <NUM> must detect both user hands within a predetermined amount of time of the first of the sensors detecting a user's hand.

In some implementations, the method <NUM> is also performed by the controller <NUM> for controller the power tool <NUM>. The controller <NUM> may only permit operation of the power tool <NUM> when the secondary switch <NUM> is actuated before the primary trigger <NUM>. For example, if the primary trigger <NUM> is actuated first, and the secondary switch <NUM> is actuated subsequent to the primary trigger <NUM>, the controller <NUM> continues to prohibit operation of the power tool <NUM>.

<FIG> illustrates a state diagram of the various states of the power tool <NUM> based on actuation of the primary trigger <NUM> and the secondary switch <NUM>. In the example of <FIG>, the indicators <NUM> include one or more light emitting diodes (LEDs). In state <NUM>, both the primary trigger <NUM> and the secondary switch <NUM> are open (e.g., de-actuated). For example, a user does not grip either the primary handle <NUM> or the secondary handle <NUM>. Accordingly, the motor <NUM> is off and the indicators <NUM> are off. If a user grabs the secondary handle <NUM>, the secondary switch <NUM> becomes closed (e.g., actuated) and the power tool <NUM> transitions to state <NUM>. In state <NUM>, the primary trigger <NUM> remains open and the secondary switch <NUM> is closed. Accordingly, in state <NUM>, the motor <NUM> remains off and the indicators <NUM> remain off. From state <NUM>, if a user grabs the primary handle <NUM> and the primary trigger <NUM> becomes closed, the power tool <NUM> transitions to state <NUM>. In state <NUM>, the both the primary trigger <NUM> and the secondary switch <NUM> are closed. Additionally, in state <NUM>, the motor <NUM> is on and driven by the controller <NUM>. The indicators <NUM> remain off.

While in state <NUM>, should the primary trigger <NUM> be released while the secondary switch <NUM> remains actuated, the power tool <NUM> returns to state <NUM>. However, should the secondary switch <NUM> be released while the primary trigger <NUM> remains actuated, the power tool <NUM> transitions to state <NUM>. In state <NUM>, the primary trigger <NUM> is closed and the secondary switch <NUM> is open. Additionally, in state <NUM>, the motor <NUM> is off and the indicators <NUM> are on. For example, the indicators <NUM> may indicate that, although the primary trigger <NUM> is closed, operation of the motor <NUM> is prohibited. In some embodiments, the indicators <NUM> may be an LED that is on or blinking to indicated that operation of the motor <NUM> is prohibited.

While in state <NUM>, should the secondary switch <NUM> be closed while the primary trigger <NUM> remained closed, the power tool <NUM> proceeds to state <NUM>. In state <NUM>, both the primary trigger <NUM> and the secondary switch <NUM> are closed. Additionally, in state <NUM>, the motor <NUM> is off and the indicators <NUM> are on. Accordingly, once the secondary switch <NUM> is released, operation of the motor <NUM> remains prohibited until the primary trigger <NUM> is released. While in state <NUM>, should the primary trigger <NUM> be released, the power tool <NUM> returns to state <NUM>. Should both the primary trigger <NUM> and the secondary switch <NUM> be released at any time during operation, the power tool <NUM> returns to state <NUM>.

In some instances, the power tool <NUM> includes a wake sequence that is automatically enabled upon wake up to suspend the typical sequence of activation (such as that described in method <NUM>). For example, if no hand is detected (at either the primary trigger <NUM> or the secondary switch <NUM>) within a predetermined time period (for example, <NUM>-<NUM>), the power tool <NUM> may become disabled and stop monitoring operations.

<FIG> illustrates a method <NUM> for a wake sequence of the power tool <NUM>. The method <NUM> may be performed by the controller <NUM>. When the power tool <NUM> wakes up from a sleep mode, at block <NUM> the controller <NUM> checks whether an initialization flag is set. If the initialization flag is not set, the controller <NUM> proceeds to block <NUM> and sets the initialization flag. If the initialization flag is set, the controller <NUM> proceeds to block <NUM> and writes capacitance (FDC) configuration and capacitance calculation data to memory <NUM>.

At block <NUM>, the controller <NUM> checks a capacitance timer value. When the capacitance timer value is equal to zero, the controller <NUM> proceeds to block <NUM>. When the capacitance value is greater than zero and less than a threshold (e.g., three milliseconds), the controller <NUM> proceeds to block <NUM>. Otherwise, the controller <NUM> proceeds to block <NUM>. Beginning with when the capacitance timer value is equal to zero, at block <NUM>, the controller <NUM> initiates a capacitance measurement. At block <NUM>, the controller <NUM> increments the capacitance timer value and returns to block <NUM>. When the capacitance value is greater than zero and less than the threshold, at block <NUM>, the controller <NUM> increments the capacitance timer value and returns to block <NUM> (e.g., waiting for a measurement).

When the capacitance timer value is greater than the threshold, at block <NUM>, the controller <NUM> reads the FDC measurement value. At block <NUM>, the controller <NUM> converts the capacitance measurement value to, for example, a <NUM> bit value. At block <NUM>, the controller <NUM> compares the capacitance measurement to a capacitance threshold. When the capacitance measurement is less than the capacitance threshold, the controller <NUM> proceeds to block <NUM> and determines the secondary switch <NUM> is open (e.g., not actuated, the secondary handle <NUM> is not held). When the capacitance measurement is greater than or equal to the capacitance threshold, the controller <NUM> proceeds to block <NUM> and determines the secondary switch <NUM> is closed (e.g., actuated, the secondary handle <NUM> is held). Otherwise, the controller <NUM> proceeds to block <NUM> and determines the state of the secondary switch <NUM> is unknown. Regardless of the comparison result, the controller <NUM> returns to block <NUM>. In some embodiments, the controller <NUM> prohibits or permits operation of the motor <NUM> based on the comparison of the capacitance measurement to the capacitance threshold. In some embodiments, the power tool <NUM> is permitted to control activation of the motor <NUM> based on actuation of the primary trigger <NUM> without receiving a signal from the secondary switch <NUM>. In such embodiments, the power tool <NUM> and controller <NUM> enter a wake mode from a sleep mode without the secondary switch <NUM> being activated (e.g., based on another sensor signal where the secondary switch <NUM> is not a wake-up source). This functions as a disablement or temporary disablement of a requirement that the secondary switch <NUM> be activated as described above.

Claim 1:
A power tool (<NUM>, <NUM>) comprising:
a housing (<NUM>, <NUM>);
a motor (<NUM>, <NUM>, <NUM>) located within the housing (<NUM>, <NUM>);
a first handle (<NUM>) having a user input (<NUM>) configured to be actuated by a first hand of a user;
a second handle (<NUM>) having a touch sensor (<NUM>) configured to detect a second hand of the user on the second handle (<NUM>); and
a controller (<NUM>, <NUM>) connected to the motor (<NUM>, <NUM>, <NUM>), the user input (<NUM>) and the touch sensor (<NUM>), the controller (<NUM>, <NUM>) configured to:
determine whether the user input (<NUM>) is actuated,
determine whether the second hand of the user is on the second handle (<NUM>) based on the touch sensor (<NUM>),
control, in response to both the user input (<NUM>) being actuated and the second hand of the user being on the second handle (<NUM>), the motor (<NUM>, <NUM>, <NUM>) to drive the motor (<NUM>, <NUM>, <NUM>),
prohibit, in response to the user input (<NUM>) being actuated and the second hand of the user not being on the second handle (<NUM>), operation of the motor (<NUM>, <NUM>, <NUM>),
and characterised in that the controller is further configured to:
determine whether the user input (<NUM>) is actuated after determining whether the second hand of the user is on the second handle (<NUM>), and
prohibit, in response to the user input (<NUM>) being actuated before the second hand of the user is on the second handle (<NUM>), operation of the motor (<NUM>, <NUM>, <NUM>).