ELECTROSTATIC DISCHARGE SYSTEM FOR A POWER TOOL

A power tool includes a housing, a motor disposed in the housing, and a transfer tube at least partially disposed within the housing, and a printed circuit board. A fan is driven by the motor to cause dust to move along the transfer tube. A static discharge mechanism extends from an interior of the housing to an exterior of the housing and is configured to dissipate electrostatic charge from the printed circuit board.

FIELD OF THE INVENTION

The present disclosure relates to power tools, and more particularly, to dust collection assemblies for use with power tools.

BACKGROUND OF THE INVENTION

Dust collection assemblies are typically used in tandem with hand-held drilling tools, such as rotary hammers, to collect dust and other debris during a drilling operation preventing dust and other debris from accumulating at a worksite. Such dust collection assemblies may be attached to a rotary hammer to position a suction inlet of the collector proximate a drill bit attached to the rotary hammer. Such dust collection assemblies may also include an on-board dust container in which dust and other debris is accumulated. Such dust containers are often removable from the dust collection assembly to facilitate disposal of the accumulated dust and debris.

SUMMARY OF THE INVENTION

In one aspect, the disclosure provides a power tool comprising a housing including a handle and a drive unit housing, a motor disposed within the drive unit housing, an output chuck configured to receive a tool bit driven by the motor for performing a working operation, a transfer tube at least partially disposed within the housing, a fan driven by the motor to induce an airflow for transporting dust and debris generated during the working operation through the transfer tube, thereby creating a static charge on the transfer tube, and a conductor disposed at least partially exposed along an exterior side of the housing to transmit the static charge that is generated during the working operation.

In one aspect, the disclosure provides a power tool comprising a housing including a first housing and a second housing, a motor disposed within the second housing, an output portion configured to receive a tool bit driven by the motor for performing a working operation, a transfer tube at least partially disposed within the housing, a fan driven by the motor and directing a static charge onto the transfer tube, and an electrostatic discharge system that is configured to transfer a charge generated at a first section of the electrostatic discharge system to a second section of the electrostatic discharge system.

In one aspect, the disclosure provides a power tool comprising a housing, a motor disposed within the housing, an output channel configured to receive a tool bit driven by the motor for performing a working operation, a transfer tube at least partially disposed within the housing, a fan driven by the motor and directing a static charge onto the transfer tube, a printed circuit board disposed within the housing, and a static discharge mechanism extending from an interior of the housing to an exterior of the housing that is configured to prevent electronic charge from building up on the printed circuit board.

In some examples, the power tool includes a conductor that extends between the transfer tube and the handle and the conductor is exposed at the handle. In some examples, the conductor includes a first conductor that is coupled to the handle, a second conductor that is coupled to the transfer tube, and a third conductor that extends between the first conductor and the second conductor. In some examples, the third conductor is a wire that extends into at least one of the handle and the drive unit housing, and extends adjacent to one of a printed circuit board a motor, and a battery receptacle. In some examples, the first conductor is a wire having a first portion coupled to an interior of the handle and a second portion coupled to an exterior of the handle. In some examples, the second conductor is a metal plate that is shaped to follow an outer contour of the transfer tube. In some examples, the power tool further includes an impact mechanism configured to be driven by an output shaft of the motor, and wherein the impact mechanism is configured to apply axial impacts to the tool bit such that the working operation includes a hammering operation. In some examples, the fan is mounted to an output shaft of the motor, and the transfer tube has an opening adjacent the output chuck. In some examples, the transfer tube is disposed within the drive unit housing portion, and the power tool further includes a dust box that is removably coupled to the drive unit housing portion for storing dust and debris passing through the transfer tube.

In some examples, the electrostatic discharge system further includes a wire, and the wire extends between the first section of the electrostatic discharge system and the second section of the electrostatic discharge system. In some examples, the transfer tube extends between the output portion and the second housing. In some examples, the power tool further includes a dust box housing within the second housing, and the fan is mounted between the motor and the dust box housing. In some examples, the electrostatic discharge system includes a metal wire that extends between a first housing portion and a second housing portion. In some examples, the electrostatic discharge system further includes a first conductor and a second conductor. In some examples, a first end of the wire is electrically connected to the first conductor, and a second end of the wire is electrically connected to the second conductor. In some examples, the power tool further includes a printed circuit board disposed within the housing. In some examples, the fan includes a first set of blades that is configured to generate a first air flow that cools the printed circuit board, and a second set of blades that is configured to generate a second air flow that induces air flow through the housing. In some examples, the power tool further includes a battery receptacle comprising an outer surface and one or more battery terminals. In some examples, the one or more battery terminals are disposed on the outer surface of the battery receptacle.

In some examples, the transfer tube is disposed within the housing, and the power tool further includes a dust box that is removably coupled to the housing for storing dust and debris passing through the transfer tube. In some examples, the static discharge mechanism includes a wire, and the wire includes a first portion, a second portion, and a third portion. In some examples, the first portion and the third portion of the wire are disposed within the housing. In some examples, the second portion extends between an inside of a handle portion of the housing to an outer surface of the handle portion of the housing. In some examples, the second portion of the wire extends along the outer surface of the handle portion of the housing from a first end to a second end, such that the first end is proximate to a battery receptacle of the power tool and a second end is proximate to a transmission housing of the power tool. In some examples, the second portion of the wire extends along the outer surface of the handle portion of the housing, such that the second portion of the wire extends in a direction that is substantially parallel to a longitudinal direction of the handle portion. In some embodiments, the transfer tube is configured to move between an extended state and a contracted state.

According to one aspect of the present disclosure, a power tool includes a housing including a handle and a drive unit housing. A motor can be disposed within the drive unit housing. An output chuck ca be configured to receive a tool bit driven by the motor for performing a working operation. A transfer tube can be at least partially disposed within the housing. A fan can be driven by the motor to induce an airflow for transporting dust and debris generated during the working operation through the transfer tube. A conductor can beat least partially exposed along an exterior side of the housing to transmit a static charge that is generated by the fan on the transfer tube during the working operation.

In some examples, the transfer tube can be within the drive unit housing and the conductor can extend between the transfer tube and the handle. The conductor can be exposed at the handle. The conductor can include a first conductor that is coupled to the handle, a second conductor that is coupled to the transfer tube, and a third conductor that extends between the first conductor and the second conductor. The third conductor can be a wire that extends into at least one of the handle, the drive unit housing, and a battery receptacle. The first conductor can be a wire having a first portion coupled to an interior of the handle and a second portion coupled to an exterior of the handle. The second conductor can be a metal plate that is shaped to follow an outer contour of the transfer tube.

In some examples, the power tool can further include an impact mechanism configured to be driven by an output shaft of the motor to apply axial impacts to the tool bit, so that the working operation includes a hammering operation. The fan can be mounted to an output shaft of the motor, and wherein the transfer tube has an opening adjacent the output chuck. The transfer tube can be disposed within the drive unit housing. In some cases, the power tool can further include a dust box that is removably coupled to the drive unit housing for storing dust and debris passing through the transfer tube.

According to another aspect of the present disclosure, a power tool can include a housing assembly, a motor disposed within the housing assembly to power a working operation with a tool bit, a transfer tube at disposed within the housing assembly, and a fan arranged within the housing assembly to induce a static charge onto the transfer tube. An electrostatic discharge system can be in electrical communication with the transfer tube at a first section of the electrostatic discharge system, and is configured to transfer a charge generated at the first section to a second section of the electrostatic discharge system to an exterior of the housing assembly.

In some examples, the electrostatic discharge system can include a wire that extends within the housing assembly between the first section of the electrostatic discharge system and the second section of the electrostatic discharge system to electrically connect the first and second sections of the electrostatic discharge system. The power tool can further include an output portion configured to receive the tool bit and the motor can be disposed within a drive unit housing spaced apart from the output portion. The transfer tube can extend between the output portion and the drive unit housing. The power tool can further include a dust box housing and the fan can be mounted between the motor and the dust box housing.

In some examples, the transfer tube can be within a first housing section of the housing assembly and the housing assembly can further include a second housing section. The electrostatic discharge system can include a wire that extends between the first housing and the second housing. The electrostatic discharge system can further include a first conductor and a second conductor. A first end of the wire can be electrically connected to the first conductor within a first housing of the housing assembly and a second end of the wire can be electrically connected to the second conductor within a second housing of the housing assembly.

In some examples, the power tool can further include a printed circuit board disposed within the housing assembly. The fan can include a first set of blades arranged to generate a first air flow that cools the printed circuit board and a second set of blades arranged to generate a second air flow that transfers dust through the transfer tube. The power tool can further include a battery receptacle comprising an outer surface and one or more battery terminals. The one or more battery terminals can be disposed on the outer surface of the battery receptacle.

According to yet another aspect of the present disclosure, a power tool can include a housing, a motor disposed within the housing, and a transfer tube at least partially disposed within the housing. A fan can be is driven by the motor to cause dust to move along the transfer tube. A printed circuit board can be disposed within the housing and configured to control operation of the motor. An electrostatic discharge mechanism can extend within an interior of the housing that is configured to dissipate electrostatic charge from the transfer tube away from the printed circuit board.

In some examples, the transfer tube can be disposed fully within the housing. The power tool can further include a dust box that is removably coupled to the housing for storing dust and debris received through the transfer tube. The electrostatic discharge mechanism can include a wire that extends between an inside of a handle portion of the housing to an outer surface of the handle portion of the housing.

DETAILED DESCRIPTION

Disclosed embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all of the disclosed embodiments are shown. Indeed, several different embodiments may be provided and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art.

As also used herein, unless otherwise defined or limited, ordinal numbers are used herein for convenience of reference based generally on the order in which particular components are presented for the relevant part of the disclosure. In this regard, for example, designations such as “first,” “second,” etc., generally indicate only the order in which the relevant component is introduced for discussion and generally do not indicate or require a particular spatial arrangement, functional or structural primacy or order.

The disclosed power tool will be described with respect to an example rotary hammer. However, it should be understood that any one or more example embodiments of the disclosed rotary hammer can be incorporated in alternate forms of a power tool, for example, hammer drills, hammer chisel, demolition hammers, etc. Furthermore, it should be understood that one or more example embodiments of the disclosed power tool can be used outside of the context of a rotary hammer and could more generally be used in a mechanism that imparts both rotational motion and axial impacts to a tool bit.

According to aspects of the disclosure a power tool can include a dust extraction system that is coupled to a housing of the power tool to suction dust and debris results during a power tool operation (e.g., drilling, chiseling, etc.). The dust extraction system creates suction via a fan that is operatively coupled to a motor to suction dust away from a work surface and transport the dust to a container for collection. Correspondingly, the dust extraction system can include tubing or the like to transfer the dust away from the work surface to the container. As the dust travels along the tube an electrostatic charge (e.g., a static charge) can build on the tubing, where it can spread to the entire tool. In particular, the static charge can migrate to printed circuit boards, sensors, and other sensitive electronic components.

To provide protection against static charge buildup, the power tool can include an electrostatic dissipation system (e.g., a discharge system or a grounding system) that prevents build-up of static charge on the power tool. The discharge system is configured to electrically ground the tool to dissipate any static charge to a grounding body (e.g., a charge sink such as earth, a work surface, a support structure, an operator, etc.). In general, the discharge system can include one or more conductors that are coupled between one or more components of the dust extraction system (e.g., tubing, dust container, etc.) and a terminal positioned external to the housing to contact the grounding body. As one particular example, a discharge system can include a first conductor that is coupled to the tube, a second conductor that is coupled to a handle of the power tool, and a third conductor that is coupled between the first conductor and the second conductor. At least a portion of the second conductor is disposed on an exterior of the handle (e.g., an exterior of the housing) to define a terminal of the discharge system. The third conductor can be a flexible wire that is configured to contact other components of the power tool (e.g., a housing, gearbox, etc.). When a grounding body (e.g., a hand of an operator) contacts the terminal, static charge that builds on the power tool can flow from the first conductor, along the third conductor, to the second conductor where it is discharged to the grounding body. It is appreciated that one or more of the first conductor, the second conductor, and the third conductor can be sections of the same conductor or can be different conductors that can be coupled together. Correspondingly, more or fewer conductors can be used.

FIGS.1A and1Billustrate a power tool10. In the illustrated embodiment, the power tool10is a rotary hammer. The power tool10includes a dust collection assembly14integrated within the body of the tool. In other embodiments, one or more portions of the dust collection assembly14may be realized as a separate element from the power tool10or may be positioned externally of the power tool10. As will be appreciated, integration of the dust collection assembly14within the power tool10may allow for a reduced number of parts for the operation of the power tool10and the dust collection assembly14. For example, in some embodiments, the dust collection assembly14and the power tool10may share certain parts. As such, integration may reduce the overall size, weight, and cost of the tool system. The profile of the tool system is also more compact, thereby allowing a user to maneuver and hold the tool system more easily. It is understood that the various features and embodiments described in the present disclosure may be mixed or interchanged into different combinations of features and embodiments. In other words, the specific combinations of features disclosed herein are not intended to be limiting but are purely for the sake of illustrating example embodiments.

The power tool10includes a housing18configured to house operating components of the power tool10therein. The housing18can define different sections or regions, which may be part of separate housings that are coupled to form the housing18as a housing assembly, or that are formed together as a unitary housing. For the purposes of this discussion, a unitary housing can include housings with a clamshell type construction that form one or more sections of the housing, with each half of the clamshell being a monolithic component. The various housing sections can correspond with a component being received therein or as forming a particular structure of the power tool10. For example, the housing18includes a drive unit housing22, a transmission housing26, a handle housing30, a battery receptacle34, and a dust box housing38. In some examples drive unit housing22, the transmission housing26, the handle housing30, the battery receptacle34, and the dust box housing38can be considered housing sections of a unitary housing. With reference toFIGS.1B and2, the drive unit housing22houses a drive unit42that is configured to produce, or generate, torque. The drive unit housing22defines a vent46that allows air to flow into and out of the housing18. In some embodiments, the drive unit housing22is formed of clamshell halves that may be coupled together (e.g., via fasteners, a snap-fit connection, etc.). The transmission housing26houses a transmission50(e.g., a transmission assembly), which is configured to receive torque from the drive unit42and rotationally drive a tool bit52(FIG.4), and an impact mechanism54, which is configured to receive torque from the transmission50and apply impacts to the tool bit52(FIG.4). The handle housing30is configured to be grasped by a user for control and operation of the power tool10.

In some implementations, the technology disclosed herein can be particularly beneficially used with the impact mechanism54as configured in the illustrated example. In other examples, however, other impact mechanisms can be used, including other arrangements known in the art to convert torque received from a motor into impacts on (or with) a tool bit.

In some examples, the handle housing30can be a separate component that is movably coupled to the rest of the housing18, which can be integrally formed with one another (e.g., in a clamshell construction). The handle can move to minimize vibration transmission to an operator. For example, in the illustrated embodiment, the handle housing30is moveably coupled to the transmission housing26at a first end30aof the handle housing30via an elastic member58. The elastic member58is configured to allow for movement of the handle housing30relative to the transmission housing26while also sealing the handle housing30from contaminants. In some embodiments, the clastic member58is replaced by a different vibration absorbing member. In some embodiments, the elastic member58is used in conjunction with another damping member, such as, for example, a spring or clastic bushing, or another type of damping element, such as a dashpot, shock absorber, etc. In the illustrated embodiment, a spring59is disposed in an internal cavity formed between the handle housing30and the transmission housing26. The spring59is configured to absorb and/or dampen vibration between the transmission housing26and the handle housing30by moving between an extended state and a compressed state. To that end, the elastic member58is configured to move between an extended state and a compressed state as the spring59moves between an extended state and a compressed state. In some embodiments, multiple damping members, such as, for example, multiple springs, are included. In some embodiments, the damping members are placed differently with respect to the transmission housing26and the handle housing30. In some embodiments, no vibration absorbing members are included. In some embodiments, the damping member(s) may be an elastic bushing, a dashpot, a shock absorber, and the like.

The battery receptacle34is positioned at a second end30bof the handle housing30opposite from the first end30a. In the illustrated embodiment, the battery receptacle34is integrally formed with the drive unit housing22and the handle housing30. As mentioned above, in some embodiments, the battery receptacle34is realized as a separate component from one or both of the drive unit housing22and the handle housing30. In some embodiments, each of the drive unit housing22, the handle housing30, and the battery receptacle34includes clamshell halves that are coupled together via fasteners. In some embodiments, the drive unit housing22, the handle housing30, and/or the battery receptacle34are unitary bodies. The battery receptacle34is configured to receive a battery62that provides power to the drive unit42for producing, or generating, torque. The dust box housing38is positioned adjacent to the drive unit housing22and is configured to store dust and debris collected by the dust collection assembly14. The dust box housing38is positioned between the drive unit housing22and the battery receptacle34.

With reference to the orientation of the power tool10inFIG.2, the power tool10has a front or forward end10a, a rear or rearward end10b, a top or upper-most end10c, and a bottom or bottom-most end10d. As such, the drive unit housing22is positioned at the forward end10aof the power tool10and positioned between the transmission housing26and the dust box housing38(e.g., in a top-to-bottom direction). The transmission housing26is positioned above the drive unit housing22at a forward and upper-most section of the power tool10. The transmission housing26extends between the drive unit housing22and the handle housing30. The handle housing30is positioned behind the transmission housing26and above the battery receptacle34(e.g., at a rearward and upper-most section of the power tool10). The battery receptacle34is positioned below the handle housing30at a rearward and bottom section of the power tool10. The battery receptacle34extends between the handle housing30and the dust box housing38. In some embodiments, the battery receptacle34extends between the handle housing30and the drive unit housing22. In some embodiments, the battery receptacle34includes a battery terminal35or a plurality of battery terminals that are located on an exterior side of the battery receptacle34. The battery terminal35provides an electrical connection to the battery62when the battery62is received in the battery receptacle34. The dust box housing38is positioned below the drive unit housing22at a forward and bottom section of the power tool10. In some embodiments, the dust box housing38extends between the drive box housing38and the battery receptacle34. In some embodiments, the dust box housing38is only coupled to the drive unit housing22. The following disclosure includes reference to directional locations such as forward, rearward, top, and bottom locations. As such, any reference made to directional location is made with respect to the directional signifier indicated inFIG.2.

In some examples, a power tool can include one or more printed circuit board assemblies (“PCB”) to control operation of the power tool. For example, with reference toFIGS.2and3, the drive unit42includes first PCB65and a second PCB66. The first PCB65is disposed in the drive unit housing22and is configured to control operation of a motor70based on an input from a user (e.g., operation of the trigger78). The PCB65can function as an electronic controller to control an electrical current that is supplied from the battery62to the motor70. The second PCB66is positioned within the drive unit housing22adjacent to the battery receptacle34. The second PCB66is configured as a sensor board that includes one or more sensors to detect an operating parameter of the motor70. In the illustrated example, the second PCB66includes a plurality of hall sensors67that are in communication with the first PCB65and that are configured to detect a rotational position of the motor70. In other examples, other types of sensors can be used, for example, speed sensors, torque sensors, etc. that can be used to detect other operating parameters of the motor70. In some embodiments, the PCB66is located between a fan shroud73and the motor70.

The motor70is a brushless direct current (“BLDC”) motor and is configured to rotate under control of the PCB66in response to user input, such as actuation of a trigger78. In some embodiments, the motor70is another type of direct current (DC) motor, alternating (AC) motor, or any other motor type. The motor70includes an output shaft82that is rotatable about a drive axis A1. A fan74, can be mounted to the output shaft82at a bottom-most end of the output shaft82(e.g., an end of the output shaft82that is closest to a body of the motor70and farthest from the transmission housing26). The fan shroud73surrounds the fan74and can help to isolate any dust and debris moved by the fan74from the rest of the power tool10by directing the dust or debris to the dust box housing38. The fan74includes a first set of blades86and a second set of blades90. The first set of blades86is positioned between the motor70and the second set of blades90. The second set of blades90is positioned above a suction inlet94defined in the drive unit housing22(e.g., the second set of blades90is positioned between the suction inlet94and the transmission housing26). In the illustrated embodiment, the fan74includes a dividing wall98that substantially separates the first set of blades86and the second set of blades90. The first set of blades86is configured to generate a first flow of air P1for, among other things, cooling the PCB66and the motor70. The second set of blades90is configured to generate a second flow of air P2for inducing air flow through the dust collection assembly14, as will be described in further detail. In the illustrated embodiment, the first flow of air P1and the second flow of air P2may be kept substantially separate from one another by the dividing wall98. In other embodiments, the fan74may not include a dividing wall98.

As illustrated inFIGS.2and4, the transmission50includes a bevel gear102and an intermediate shaft106that defines a transmission axis A2extending in a front-to-rear direction (FIG.2). In some embodiments, the transmission axis A2is defined along the length of the intermediate shaft106between a first end and a second end of the intermediate shaft106. In some embodiments, a cage and peg gear, a worm gear, a spur gear, or a different gear is used in place of or in conjunction with the bevel gear102. The transmission axis A2is substantially perpendicular to the drive axis A1. In some embodiments, the intermediate shaft106and the corresponding transmission axis A2are at an acute angle relative to the drive axis A1. The bevel gear102includes a bevel input gear110and a bevel output gear114. The bevel input gear110is mounted to the output shaft82of the drive unit42for rotation with the output shaft82about the drive axis A1. The bevel output gear114is supported by the housing18and is oriented substantially perpendicular to the bevel input gear110for converting rotation about the drive axis A1from the drive unit42to rotation about the transmission axis A2. The intermediate shaft106is also supported by the housing18and extends through the bevel output gear114such that the intermediate shaft106is configured to rotate with the bevel output gear114. The intermediate shaft106includes at least one pinion gear118at an end of the intermediate shaft106opposite from the bevel output gear114.

The impact mechanism54includes a hammer122and a spindle126that defines an impact axis A3extending in a front-to-rear direction. The spindle In some embodiments, the impact axis A3is substantially perpendicular (e.g., to be within about 15 degrees of perpendicular) to the drive axis A1and is substantially parallel to the transmission axis A2. In other embodiments, the impact axis A3may be oriented differently, for example, so that the impact axis A3is substantially parallel (e.g., to be within about 15 degrees of parallel) to the drive axis A1and substantially perpendicular to the transmission axis A2. The hammer122is reciprocated by the motor70(via the transmission50) to impart axial impacts to the tool bit52. The hammer122is coupled to the intermediate shaft106of the transmission50such that rotation of the intermediate shaft106effects the hammer122spindle to oscillate at periodic intervals (e.g., to generate reciprocating linear motion). Specifically, the hammer122reciprocates a direction extending along the impact axis A3. The spindle126is rotated by the motor70(via the transmission50) to cause rotation of a tool bit. The spindle126includes a drive gear130coupled thereto that is meshed with the pinion gear118of the intermediate shaft106such that the intermediate shaft106is configured to drive rotation of the spindle126via the engagement between the pinion gear118on the intermediate shaft106and the anvil gear130on the spindle126.

With continued reference toFIGS.2and4, the power tool10includes an output chuck134that extends through the transmission housing26at the forward end10aof the power tool10. The output chuck134is configured to receive the tool bit52. In the illustrated embodiment, the output chuck134includes a ball detent mechanism138for retaining the tool bit52. In some embodiments, other retention mechanisms, such as a keyless chuck, a keyed chuck, and/or a hybrid chuck, are used in place of or in conjunction with the output chuck134including the ball detent mechanism138. When the tool bit52is received in the output chuck134, the tool bit52extends along and is configured to rotate about the impact axis A3. As such, the impact axis A3may also be referred to as an output axis A3. In other embodiments, the output chuck134may include different features for retaining a tool bit52. The output chuck134is engaged with the spindle126such that rotation from the transmission50and axial impacts from the impact mechanism54may be transferred to the tool bit52when the tool bit52is coupled to the output chuck134. As such, the drive unit42is configured to rotationally drive the tool bit52through the transmission50and the spindle126for performing a drilling operation, and is configured to produce axial impacts on the tool bit52through the transmission50and the impact mechanism54for performing a hammering operation. In some embodiments, the power tool10includes a mode selection actuator that is engaged with the transmission50and the impact mechanism54for placing the power tool10in a hammer-only mode, a drilling-only mode, or a hammer and drilling mode.

With reference toFIGS.2and4, in some embodiments, a spindle126is disposed within the output chuck134and between the tool bit52and the spindle126. In some embodiments, the transmission50transmits torque from the motor70to the spindle126, causing the spindle126to rotate when the motor70is activated. Disposed within the spindle is an anvil140that is disposed between a distal end of the spindle126and the spindle126. In some embodiments, a distal end of the anvil140that is disposed closest to the tool bit52is used as a striking face to produce axial impacts on the tool bit52. The transmission housing26(e.g., a gearbox) may further include a striker141, a piston142, and a yoke143. In some embodiments, the hammer122drives the piston142to reciprocate in response to rotation of the intermediate shaft106.

FIGS.2and4illustrate the impact mechanism54of the power tool10. The impact mechanism54is configured to impart repeated axial impacts to a tool bit52. The impact mechanism54can generate impact energy via an oscillation mechanism (e.g., the hammer122) that converts the rotational motion of the motor70into reciprocating linear motion. The impact mechanism (e.g., the oscillation mechanism) can be driven by the motor70. In some cases, the impact mechanism can be driven by (e.g., receive an input from) the transmission50, or it can be driven by a separate drive system. The impact mechanism can include an oscillating mechanism that is configured to convert rotational motion of the motor70into reciprocating linear motion that is used to deliver repeated (axial) impacts to the tool bit52. The oscillation mechanism can be configured as, for example, a cam-follower, crank-slider, swashplate, or another type of system configured to generate reciprocating linear movement from a rotational input. In this case, the hammer122is part of a wobble bearing assembly that causes the rotational motion of the intermediate shaft106to generate reciprocating motion of the hammer122that causes the piston142to reciprocate within the spindle126. More specifically, wobbling movement of the hammer122is transmitted to reciprocation motion to the piston142to drive the piston142to reciprocate. For example, the hammer122is movably coupled to the yoke143that drives the linear reciprocating motion of the piston142. In some embodiments, the yoke143is disposed between the hammer122and the piston142. In some embodiments, the piston142is disposed between the yoke143and the striker141. In some embodiments, the striker141is disposed between the anvil140and a distal end of the piston142that is closest to the yoke143. In some embodiments, the anvil140is disposed between the striker141and the tool bit52.

With continued reference toFIG.2, the piston142is hollow and defines an interior chamber in which the striker141is movably received. An air spring is developed between the piston142and the striker141. When the piston142reciprocates within the spindle126, the piston142and the striker141can move relative to one another. For example, as the piston142is moved toward the anvil140, the air pocket is compressed, and as the piston142is moved away from the anvil140, the air pocket is expanded. This expansion and retraction of the air pocket results in pressure changes in the air pocket that cause reciprocation of the striker141.

With additional reference toFIGS.2and4, the anvil140is configured to impart axial impacts onto the tool bit52in response to the reciprocation of the piston142and the striker141.

In operation, when the tool bit52is attached to the output chuck134and depressed against a workpiece, the tool bit52pushes the striker141(via the anvil140) toward the piston142to attain an “impact” position of the striker141. During operation of the power tool10, the piston142reciprocates within the spindle126to draw the striker141away from the anvil140and then accelerate it towards the anvil140for impact.

As illustrated inFIG.2, the dust collection assembly14includes a dust tube144, a depth setting mechanism146, a dust transfer tube150, and a filter154. The dust collection assembly14is configured to perform a suctioning operation during the drilling and/or hammering operation. Specifically, dust and debris may be generated during the drilling and/or hammering operation, and the dust collection assembly14is configured to suction the dust and debris away from a work surface and into the dust box housing38, as will be described in more detail.

The dust tube144extends from the output chuck134such that the tool bit52(FIG.4) may extend through the dust tube144. In the illustrated embodiment, the dust tube144is formed of a flexible material, such as a fabric (e.g., nylon) or flexible plastic that is compressible to move between an extended state and a collapsed state. In some examples, a biasing element can be provided to bias the dust tube144away from the output chuck134in the extended state. In the illustrated example, a biasing element is configured as a spring158and is positioned within the dust tube144and biases the dust tube144away from the output chuck134in the extended state. During the drilling and/or the hammering operation, the spring158, and therefore the dust tube144, may be compressed against a work surface to move the dust tube144toward the collapsed state. In other embodiments, the dust tube144may be a rigid tube or a telescoping tube.

With reference toFIGS.2,5A, and5B, the depth setting mechanism146includes a guide rail162and an adjustment knob166. The guide rail162has a first end162apositioned at the transmission housing26and a second end162bpositioned at a forward-most end of the dust tube144. The guide rail162is configured to slide along a groove170formed in the transmission housing26as the dust tube144moves between the extended state and the collapsed state. The adjustment knob166is positioned in the groove170and is configured to set the insertion depth for the tool bit52(FIG.4) of the power tool10into a work surface. That is, as the dust tube144moves between the extended state and the collapsed state, the first end162aof the guide rail162may move rearwardly until the first end162aof the guide rail162hits, or engages, the adjustment knob166such that the adjustment knob166inhibits further rearward movement of the guide rail162(e.g., away from the extended state). As such, if a relatively small bore hole is desired, the adjustment knob166may be placed adjacent to the first end162aof the guide rail162(e.g., as illustrated inFIG.5A) such that rearward movement of the guide rail162is inhibited shortly after the tool bit52(FIG.4) is inserted into a work surface. If a relatively larger bore hole is desired, the adjustment knob166may be moved along the groove170to a position further away from the first end162aof the guide rail162(e.g., as illustrated inFIG.5B) such that the dust tube144is able to move to the collapsed state before the first end162aof the guide rail162reaches the adjustment knob166.

With reference toFIG.2, the dust transfer tube150includes an inlet174and an outlet178. The inlet174defines an opening adjacent to the output chuck134. Specifically, the inlet174is positioned substantially between the output chuck134and the dust tube144. In the illustrated embodiment, the inlet174surrounds a portion of the output chuck134such that the tool bit52(FIG.4) is configured to extend at least partially through the inlet174of the dust transfer tube150. The outlet178is positioned at an interface between the drive unit housing22and the dust box housing38. As such, the dust transfer tube150defines a pathway between the inlet174and the outlet178for airflow, including dust and debris, to travel from the dust tube144to the dust box housing38. In the illustrated embodiment, with reference toFIGS.2and8, the dust transfer tube150has an outer profile defined by a first portion150athat extends in a rearward direction (e.g., toward the handle housing30), a second portion150bthat extends in a rearward and downward (e.g., diagonal) direction (e.g., toward the handle housing30and dust box housing38), and a third portion150cthat extends in a downward direction (e.g., toward the dust box housing38).

As illustrated inFIG.2, the filter154is positioned below or at the suction inlet94in the drive unit housing22. As such, the filter154is positioned below the second set of blades90such that the second set of blades90induces the second flow of air P2into the dust tube144, through the dust transfer tube150to the dust box housing38, through the filter154, and out of the vent46(FIG.1B) defined in the drive unit housing22. As the second flow of air P2passes through the filter154, dust and debris is separated from the second flow of air P2. The separated dust and debris may then be stored in the dust box housing38until the dust box housing38is cleaned out. Specifically, the dust box housing38may be removably coupled to the drive unit housing22such that the dust box housing38is removable to clean dust and debris from the dust box housing38.

In some examples, the handle housing30includes an electrostatic discharge mechanism (e.g., a conductor) that is configured to collect and contain static discharge until it is grounded. In some embodiments, the component is configured to be contacted by a user, such that contact with the user grounds the static discharge. In some embodiments, the electrostatic discharge mechanism is configured to ground the static discharge using a grounding port, a cable, or another form of transferring or dissipating the static discharge. With reference toFIGS.6-8, in the illustrated embodiment, the power tool10further includes an electrostatic discharge system182positioned in the housing18of the power tool10. Specifically, the electrostatic discharge system182includes a conductor184that includes a first conductor186that is positioned in the handle housing30, a second conductor190that is positioned in the drive unit housing22, and a third conductor194(e.g., a wire) that extends between the first conductor186and the second conductor190. In the illustrated example, the wire194can be a flexible or rigid, elongate conductor, for example, a braided or solid core wire, bus bar, or another type of conductor as known in the art. The first conductor186is configured to dissipate static charge to a user when the user's hand grasps the handle housing30, the second conductor190is configured to localize, or centralize, static charges generated during the drilling and/or hammering operation and suctioned through the dust transfer tube150, and the wire194extends between the first conductor186and the second conductor190to transmit static charge from the second conductor190to the first conductor186. Specifically, a first end194aof the wire194is electrically connected to the first conductor186, and a second end194bof the wire is electrically connected to the second conductor190. In some embodiments, the wire194is replaced by or used in conjunction with a different conductor, such as, for example, a sheet of metal, a rod, conductive polymers (e.g., polymers with a conductive additive), or other conductors of the like.

In the illustrated embodiment shown inFIG.7, the first conductor186is a metal wire having a first portion186acoupled to the housing18within an interior of the handle housing30, a second portion186bthat extends external to the housing18from the first portion186a, and a third portion186cthat extends into the interior of the handle housing30from the second portion186band is coupled to the housing18. Each of the first portion186aand the third portion186cis coupled to the housing18at posts extending from at least one of the clamshell halves of the housing18. The second portion186bextends between apertures200in the handle housing30and extends along an outer surface of the handle housing30. Specifically, the second portion186bextends along a forward-most outer surface of the handle housing30(e.g., a surface of the handle housing30that faces the drive unit housing22) such that a user's hand grasping the handle housing30contacts the first conductor186. Upon contact between the first conductor186and the user's hand, static charges generated during the working operation may be grounded, and therefore, unexpected and undesired shocks may be prevented. In some embodiments, the second portion186bextends along a rearmost outer surface of the handle housing30(e.g., a surface of the handle housing30that faces away from the drive unit housing22), wraps around the handle housing30, or is otherwise disposed on the outer surface of the handle housing30such that the second portion186bis configured to be contacted by a user's hand or other grounding mechanism during use.

With reference toFIG.8, the second conductor190is a plate that is coupled to the dust transfer tube150of the dust collection assembly14. In some embodiments, the second conductor190is a metal plate. The second conductor190is shaped to follow the outer contour, or profile, of the dust transfer tube150. In other words, the second conductor190can extend along (e.g., substantially parallel with or seated on) the outer contour of the dust transfer tube150. As such, the second conductor190includes a first portion190athat extends in a rearward direction (e.g., toward the handle housing30), a second portion190bthat extends in a rearward and a downward (e.g., diagonal) direction (e.g., toward the handle housing30and the dust box housing38), and a third portion190cthat extends in a downward direction (e.g., toward the dust box housing38). The second conductor190may attract static charge from dust and debris generated during the drilling and/or hammering operation and suctioned through the dust transfer tube150. The wire194then transmits the static charge from the second conductor190to the first conductor186. In the illustrated embodiment, the wire194may extend through the drive unit housing22around a periphery of the motor70to reach the first conductor186in the handle housing30. In other embodiments, the wire194may extend through the drive unit housing22around the periphery of the fan shroud73.

The electrostatic discharge system182advantageously prevents the buildup of static charges within and/or on the housing18of the power tool10. In particular, the electrostatic discharge system182can direct electrostatic buildup away from the PCB66or dissipate electrostatic charge that has built on PBC66. The electrostatic discharge system182can similarly direct electrostatic buildup away from or dissipate electrostatic charge that has built on other electronic components, including the motor70, the battery62, sensors of the power tool10, etc. For example, in absence of the electrostatic discharge system182, dust and debris may move through the dust transfer tube150and carry an electric charge into the power tool10. Without providing a way for dissipating the static charge, the static charge may migrate to any of the printed circuit boards within the tool10or the handle housing30. As such, once a user grasps the handle housing30for operating the power tool10, the static charge may become grounded through the user's hand, thereby causing the user to feel an unwanted shock. Therefore, the electrostatic discharge system182improves the comfort and ease of use of the power tool10.

Although the disclosure has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the disclosure as described. Various features of the present disclosure are set forth in the following claims.