Belt Sander

This application is a continuation of co-pending U.S. patent application Ser. No. 17/717,503, filed Apr. 11, 2022, now U.S. Pat. No. 12,397,390, which claims priority to U.S. Provisional Patent Application No. 63/301,212, filed Jan. 20, 2022, U.S. Provisional Patent Application No. 63/274,789, filed Nov. 2, 2021, U.S. Provisional Patent Application No. 63/246,655, filed Sep. 21, 2021, and U.S. Provisional Patent Application No. 63/173,545, filed Apr. 12, 2021, the entire contents of all of which are incorporated by reference herein.

The present invention relates to power tools, and in particular to portable belt sanders.

Belt sanders generally include an abrasive sanding belt that is driven in a continuous loop. Typically, there is a series of drums that drive the sanding belt in a continuous loop, where the drums are spaced apart to create lateral runs therebetween. One of the lateral runs can be pressed against a workpiece to perform a sanding operation.

In one embodiment, the invention provides, among other things, a belt sander for sanding a workpiece and defining a center of gravity within a first plane. The belt sander includes a main housing, a handle defining a second plane, and a drive unit disposed within the main housing. The drive unit includes a motor disposed adjacent a first lateral sidewall of the main housing, a pulley system disposed adjacent a second lateral sidewall of the main housing opposite the first lateral sidewall, and a transmission disposed between the motor and the pulley system. The belt sander further includes a belt drive system driven by the drive unit. The belt drive system includes a drive wheel that is driven by the pulley system, a driven wheel that is driven by the drive wheel via a sanding belt, and a platen disposed between the drive wheel and the driven wheel to press the sanding belt against a workpiece. The platen defines a third plane extending perpendicular therefrom. The transmission and pulley system are disposed on one side of the first plane and the motor is disposed on an opposite side of the first plane. The motor is intersected by the second plane and the third plane.

In another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a handle, and a main housing having a first lateral sidewall, a second lateral sidewall opposite the first lateral sidewall, and a front end being perpendicular to the first lateral sidewall. The belt sander further includes a drive unit disposed within the main housing between the first lateral sidewall and the second lateral sidewall, and a belt drive system driven by the drive unit. The belt drive system has a drive wheel, a driven wheel, and a sanding belt for engaging the workpiece. The belt sander further includes a first light disposed on the first lateral sidewall and a first lens for projecting light onto a first area of the workpiece that runs alongside the first lateral sidewall. The belt sander further includes a second light disposed on the front end and a second lens for projecting light onto a second area of the workpiece that is adjacent the driven wheel.

In yet another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a main housing, a handle extending from the main housing, a drive unit disposed within the main housing, a battery for selectively supplying electrical power to the drive unit, and a belt drive system driven by the drive unit. The belt drive system has a drive wheel, a driven wheel driven by the drive wheel via a sanding belt, and a platen for pressing the sanding belt against a workpiece while the sanding belt is rotated about the drive wheel and the driven wheel, creating dust and debris from the workpiece. The belt sander further includes a dust extraction unit driven by the motor transporting dust and debris away from the workpiece, and a dust bag positioned downstream of the dust extraction unit to receive dust and debris therefrom. The dust bag has a rectangular shape, and wherein the dust bag includes a zipper extending along first and second edges of the dust bag.

In still another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a handle, a main housing having a first clamshell half and a second clamshell half that are secured together along a joint to form the main housing, a drive unit disposed within the main housing, and a battery for selectively supplying electrical power to the drive unit. The belt sander further includes a belt drive system driven by the drive unit. The belt drive system has a drive wheel, a driven wheel, and a sanding belt for engaging the workpiece. The belt sander further includes a first wire disposed within the first clamshell half and a second wire disposed within the second clamshell half. The first and second wires conduct electrical current from the battery to components within the belt sander. The belt sander further includes a wiring bridge that spans the joint between the first and second clamshell halves to electrically connect the first wire and the second wire. The wiring bridge is compressed when the first and second clamshell halves are coupled together.

In still yet another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a main housing, a handle extending from the main housing, a drive unit disposed within the main housing, a battery for selectively supplying electrical power to the drive unit, and a first pulley system driven by the drive unit and having a first belt tensioner that is biased against a first pulley belt to remove excess slack from the first pulley belt. The belt sander further includes a belt drive system driven by the first pulley system and having a drive wheel, a driven wheel driven by the drive wheel via a sanding belt, and a platen for pressing the sanding belt against a workpiece while the sanding belt is rotated about the drive wheel and the driven wheel, creating dust and debris from the workpiece. The belt sander further includes a second pulley system driven by the drive unit and having a second belt tensioner that is biased against a second pulley belt to remove excess slack from the second pulley belt. The belt sander further includes a dust extraction unit driven by the second pulley system for transporting dust and debris away from the workpiece.

In still yet another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a main housing, a handle extending from the main housing, a drive unit disposed within the main housing and including a motor that drives a drive shaft about a drive axis, and a battery for selectively supplying electrical power to the drive unit. The belt sander further includes a pulley system having a first pulley coupled to and driven by the drive shaft of the motor and a second pulley driven by the first pulley via a pulley belt. The belt sander further includes a belt drive system driven by the pulley system and having a drive wheel, a driven wheel driven by the drive wheel via a sanding belt, and a platen for pressing the sanding belt against a workpiece while the sanding belt is rotated about the drive wheel and the driven wheel. The belt sander further includes a belt tensioner for removing excess slack from the pulley belt, wherein the belt tensioner is capable of moving the first pulley relative to the second pulley during an adjustment state and inhibiting the first pulley from moving relative to the second pulley when the pulley belt is sufficiently tensioned during a locked state.

In still yet another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a main housing, a handle extending from the main housing, a drive unit disposed within the main housing, a battery for selectively supplying electrical power to the drive unit, and a belt drive system driven by the drive unit. The belt drive system has a drive wheel, a driven wheel driven by the drive wheel via a sanding belt, and a platen defining a front edge disposed adjacent the driven wheel, a rear edge disposed adjacent the drive wheel, a bottom side disposed adjacent the workpiece, and a top side opposite the bottom side. The belt sander further includes a platen attachment that is removably coupled to the platen and is configured to press the sanding belt against a workpiece while the sanding belt is rotated about the drive wheel and the driven wheel. The platen attachment includes a lip that bends around at least one of the front edge or the rear edge from the bottom side to the top side, wherein the lip is coupled to the top side of the platen.

In still yet another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a main housing, a handle extending from the main housing, a drive unit disposed within the main housing, a battery for selectively supplying electrical power to the drive unit, and a belt drive system driven by the drive unit. The belt drive system has a drive wheel, a driven wheel driven by the drive wheel via a sanding belt, and a platen defining a front edge disposed adjacent the driven wheel, a rear edge disposed adjacent the drive wheel, a bottom side disposed adjacent the workpiece, and a top side opposite the bottom side. The belt sander further includes a platen attachment that is removably coupled to the platen and is configured to press the sanding belt against a workpiece while the sanding belt is rotated about the drive wheel and the driven wheel. The belt sander further includes a wear skid that is removably coupled to the rear edge of the platen and protrudes beyond the platen attachment. The wear skid extends into the path of the sanding belt between the drive wheel and the platen attachment.

In still yet another embodiment, the invention provides, among other things, a belt sander for sanding a workpiece including a main housing, a handle extending from the main housing, a drive unit disposed within the main housing, a battery for selectively supplying electrical power to the drive unit, and a pulley system driven by the drive unit. The pulley system includes a first pulley, a second pulley, and a pulley belt having an upper run and a lower run. The belt sander further includes a vibration dampening system disposed adjacent to and selectively engaging the pulley system to inhibit oscillations within the pulley belt. The vibration dampening system includes at least one wave disruptor positioned away from outer periphery of the pulley belt, such that the pulley belt contacts the at least one wave disruptor when the upper run or the lower run of the pulley belt deviates from a straight-line path.

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

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

illustrates a portable power tool, such as a belt sander, for sanding a workpiece. In the illustrated embodiment, the belt sanderincludes a main housing, a main frame() that supports the main housing, a primary handleused for gripping and maneuvering the sanderalong a workpiece, and a pommel or secondary handlethat is selectively grasped by a user to further stabilize the sanderduring operation. The main housingis comprised of two clamshell halvesthat are connected together with threaded fasteners (e.g., screws), but may alternatively be secured together using other suitable coupling means.

With reference to, the belt sanderfurther includes a drive unitthat is positioned within the main housingand operable to drive a sanding belt(). Specifically, the drive unitincludes an electric motor(e.g., a brushless DC electric motor) capable of producing a rotational output through a drive shaftwhich, in turn, provides a rotational input to a transmission. The motordefines a motor axisalong which the drive shaftand the transmissionare coaxially aligned. The belt sanderis powered by a battery pack, as shown in. The battery packconnects to the primary handleand provides electrical power to the motorwhen a triggeris depressed. The triggeris conveniently positioned adjacent the primary handleto allow a user to maneuver and activate the belt sanderwith a single hand.

With reference to, the transmissionincludes a transmission housingaffixed to the main frame, a single planetary gear stageincluding a ring gearpositioned within the transmission housingand three planetary gearsintermeshed with the ring gear. An output shaftis coupled for co-rotation with a carrierin the planetary gear stageto thereby receive the torque output of the transmission. The output shaftis coaxial with the motor axis. In other embodiments, the ring gearreceives the torque output of the transmissionto drive the output shaft. Although the transmissionof the illustrated embodiment includes a single planetary gear stage, in other embodiments, the transmissionmay alternatively include two or more planetary gear stages. Still in other embodiments, the transmissionmay alternatively include one or more spur gear sets, one or more helical gear sets, or other styles of transmissions.

With reference to, the drive unitfurther includes a first pulley systemthat is driven by the output shaftof the transmission. The first pulley systemis downstream of the transmission, such that the transmissionis positioned between the motorand the first pulley systemin a direction along the motor axis. As a result, the output shaft(and therefore, the first pulley system) has a reduced angular velocity compared to the drive shaftdue to the gear reduction of the transmission. The first pulley systemincludes a first pulleycoupled for co-rotation with the output shaftand a second pulleydriven by the first pulleyvia a pulley belt() about a driven shaft. Both the first pulleyand the second pulleyare supported by the main frame. On the outer periphery of the first and second pulley,are teeththat intermesh with corresponding teethof the pulley beltto provide a positive engagement therebetween and a synchronous drive between the beltand the pulleys,. The second pulleyis coupled to a drive belt system() that drives the sanding belt, as described in further detail below.

With reference to, the drive belt systemincludes a drive wheel, a driven wheeldriven by the drive wheelvia the sanding belt, and a platendisposed between the drive wheeland the driven wheel. In some embodiments, the platenis integrally formed with the main frame(). When the sanding beltis being driven by the drive wheel, the sanding beltslides along the platen(or a platen attachmentcoupled to the platen, as shown in), creating a flat, working surfacethat presses the sanding beltagainst a workpiece. The drive wheelis disposed adjacent a rear endof the belt sanderand defines a drive wheel axis, whereas the driven wheelis disposed adjacent a front endof the belt sanderand defines a driven wheel axis. As illustrated in, the motor axis, the drive wheel axis, and the driven wheel axisare all parallel. A tensioning mechanismis coupled to the driven wheeland is capable of moving the driven wheelbetween a retracted position, in which the sanding beltmay be removed from the sander, and an extended position, in which the sanding beltis placed under tension and inhibited from being removed from the sander. Specifically, the driven wheelmoves toward the drive wheelin the retracted position to allow the sanding belt—having a fixed, rigid circumference—to fit around the drive wheelthe driven wheel, and the platen.

Returning to, the components of the belt sanderare situated in a specific arrangement to improve the center of gravity, ergonomics, longevity, and performance of the belt sander, as described in further detail below. The main housingincudes a first lateral sidewall(as represented by broken line in) and a second lateral sidewallopposite the first lateral sidewall. The belt sanderdefines a center of gravity that is located between first and second lateral sidewalls,. Specifically, the center of gravity for the belt sanderis located within a first upright planethat is approximately equal distance from the first and second lateral sidewalls,. By positioning the transmissionbetween the motorand the first pulley system, the plane(which contains the center of gravity) is situated centrally within the belt sanderbecause the weight of the motoris positioned proximate the first lateral sidewall, thereby counteracting the weight of the first pulley systempositioned proximate the second lateral sidewallwithout increasing the length of the drive shaft. That is, the transmissionenables the motorand the first pulley systemto be positioned further apart (i.e., near opposite lateral sidewalls,) without compromising the integrity of the drive shaft. As a result, the transmissionavoids unnecessary length extensions of the drive shaft, which can inadvertently cause excessive shaft vibration, reduced tool balance, excessive torsional deflection, reduced shaft longevity, and reduced longevity of connected components (e.g., the motor, the first pulley system, etc.).

With continued reference to, the primary handledefines a second upright planethat extends through the center of the primary handle, while the platendefines a third upright planethat extends through the center of the platenin a direction perpendicular to the platen. Each plane,,is parallel and substantially perpendicular relative to a support surface (e.g., the ground). As shown in, the first upright planeis closer to the second upright planethan the third upright plane. Also, the first lateral sidewallis closer to the third upright planethan the second upright plane. In this configuration, the motoris intersected by both the second upright planeand the third upright plane. By positioning the motorin this manner, the motoris adjacent the first lateral sidewallwhile the first pulley systemis adjacent the second lateral sidewall, thereby providing sufficient volume within the main housingto accommodate the transmission. This configuration of components (e.g., the motor, the transmission, and the first pulley system) also moves the first upright plane, and therefore the center of gravity, towards the third upright plane, which optimizes weight distribution on the working surface. As a result, the reliability of the belt sanderis increased, and the vibration and noise emitted by the drive unitis also decreased. Further, the ergonomics of the belt sanderis improved due to the optimized center of gravity.

With reference to, the belt sanderfurther includes a first lightwith a first lensdisposed on the first lateral sidewalland a second lightwith a second lensdisposed on the front end. The lights,provide a user increased visibility during operation, especially in instances where light may be limited (e.g., dark corners of a workpiece). In the illustrated embodiment, the lights,are light-emitting diodes (LEDs), but may alternatively be different types of lights in other embodiments.

Referring to, the first lensis a convex lens, such that light emitted from the LED diverges outward from the first lateral sidewalland projects downward onto area Aof a workpiece that runs alongside the first lateral sidewall. Similarly, the second lensis a convex lens, such that light emitted from the LED diverges outward from the front endand projects downward onto area Aof a workpiece that is adjacent the driven wheel. The second lensalso projects light outward in front of the belt sanderonto area Aof a workpiece to reveal deformities and finish quality on a workpiece. Specifically, the second lightis positioned in the lower half of the main housingon the front end, such that the incident ray (i.e., light rays coming from the second light) has an acute angle of incidence relative to a workpiece, creating shadows on a workpiece where deformities may exist in front of the front end. Generally, the absence of shadows on a workpiece indicates absence of deformities (e.g., bumps, divots, scratches, etc.). Lastly, the first and second lights,assist a user from inadvertently running into and damaging (e.g., marring) walls of a workpiece due to lack of light.

With reference to, the secondary handleof the belt sanderis moveable relative to the main housing. Specifically, the main housingincludes a rail, upon which the secondary handleis moveably mounted along a rail axis(). The secondary handleincludes a lock systemthat is pivotable between a locked state, in which the secondary handleis inhibited from moving along the rail, and an unlocked state, in which the secondary handleis permitted to move along the rail.

With continued reference to, the lock systemincludes an axle() received within corresponding counterboresin the secondary handle, a cam bodydisposed around the axle(), and a leverextending away from the cam bodyand capable of rotating the cam body. In the locked state, the leveris substantially flush (i.e., flush, slightly sub-flush, or slightly proud, etc.) with the geometry of the secondary handle, such that a user does not feel the leverwhen it is in the locked state. However, at a distal end of the leveris a lipthat extends beyond the secondary handleto allow a user to grasp the leverwhen the lock systemis in the locked state. Furthermore, the cam body() is received within one of two arcuate recesseson the railwhen the lock systemis in the locked state. As such, the secondary handleis moveable along the railbetween two discrete positions—a rearward position (as represented by phantom lines in) and a forward position (as represented by solid lines in). In the rearward position, the cam bodyis received within the arcuate recessIn the forward position, the cam bodyis received within arcuate recess

Not only does the cam bodymechanically interfere with the railto inhibit movement of the secondary handlerelative to the rail, but the cam bodyalso mechanically interferes with the arcuate recesseswhen received therein. The mechanical interference between the cam bodyand the arcuate recessescauses the lock systemto displace upward relative to the railagainst the bias of a spring(). As a result of the lock systemdisplacing upwardly, the springdeforms and a force component Fis exerted on a trackof the secondary handle, causing the secondary handleto displace in a direction substantially perpendicular to the rail axis. Subsequently, the slop (i.e., play) or relative movement between the trackof the secondary handleand the railis limited when the lock systemis in the locked state. At this point, there is increased surface area contact between the trackand the rail, which increases friction and inhibits the secondary handlefrom moving. In the illustrated embodiment, the springis an O-ring disposed between the axleand each counterboreof the secondary handle. The spring(or O-ring) is composed of an elastomeric material, allowing for relative movement between the axleand the counterboreof the secondary handle. In other embodiments, the springmay alternatively be a compression spring, an extension spring, or other elastic material capable of elastic deformation.

With reference to, the lock systemfurther includes a plateau, which is a flat region disposed on the cam bodythat creates a discontinuity on the cam body. The plateauremoves the cam bodyfrom the railwhen the lock systemis in the unlocked state. Specifically, the plateauis disposed on the cam body, such that the cam bodyis spaced away from the railwhen the lock systemis in the unlocked state. In other words, the cam bodyis removed from one of the arcuate recessesand the plateauis substantially parallel to the rail axiswhen the lock systemis actuated to the unlocked state. At this point, the trackof the secondary handleis capable of sliding along the railbetween the rearward position and the forward position. Once the secondary handleis moved to either the rearward position or the forward position, the plateauis aligned with the respective arcuate recessat which point the lock systemmay be actuated to the locked state where the cam bodyrotates into the respective arcuate recessIn the unlocked state, the leverexperiences rotational resistance due to frictional forces as the axleslides within the spring(i.e., O-ring).

With reference to, the belt sanderfurther includes a dust extraction unitcoupled to and extending from the main housing. The dust extraction unitdraws dust particles and other debris away from a workpiece and collects the debris in a dust bagduring operation. The dust extraction unitincludes a shroudand a fandisposed within the shroud. The shroudincludes an inletthat is adjacent the platenand an outletthat is adjacent the dust bag. The fanis driven by the motorvia a pulley beltof a second pulley system(including a first pulleyand second pulley;), such that the fanis configured to create a low-pressure region near the platento draw debris into the inlet. As shown in, the second pulley systemis coupled to the drive shaftupstream of the transmissionvia the first pulley. That said, the transmissionis disposed between the first pulley systemand the second pulley system. As a result, the first pulley systemand the second pulley systemare coaxially driven along the motor axis, albeit at different speeds. Specifically, the first pulley systemis driven at a first speed that is identical to the angular velocity of the output shaft, whereas the second pulley systemis driven at a second speed that is identical to the angular velocity of the drive shaft. The angular velocity of the second speed is greater than the angular velocity of the first speed due to the gear reduction of the transmission. Although the first and second pulley systems,are being coaxially driven along the motor axis, in other embodiments, the first and second pulley systems,may alternatively be driven along parallel axes.

With reference to, the first pulley systemfurther includes a first belt tensionerand the second pulley systemincludes a second belt tensioner. The first belt tensioneris mounted to the main frameand disposed within the inner periphery of the pulley beltof the first pulley system. The first belt tensionerincludes an axlecoupled to the main frame, an armcoupled to and extending perpendicularly relative to the axle, and a first rollerrotatably coupled to the arm. The first rollerextends away from the arminto the path of the pulley belt, such that the first rolleris in contact with the pulley belt. A spring(e.g., a torsion spring, etc.) is disposed around the axleand biases the armin a clockwise direction (frame of reference from) to bias the first rollerinto contact with the inner periphery of the pulley belt.

With reference to, the second belt tensioneris also mounted to the main frameand disposed within the inner periphery of the pulley beltof the second pulley system. The second belt tensionerincludes an axlecoupled to the main frame, an armcoupled to and extending perpendicularly relative to the axle, and a second rollerrotatably coupled to the arm. The second rollerextends away from the arminto the path of the pulley belt, such that the second rolleris in contact with the pulley belt. A spring(e.g., a tension spring, etc.) is coupled between the main frameand the arm, and biases the armin a counterclockwise direction (frame of reference from) to bias the second rollerinto contact with the inner periphery of the pulley belt. The first belt tensionerand the second belt tensionerapply tension to the respective pulley belts,, thereby reducing belt tension variation and prolonging the longevity of the pulley belts,.

In other embodiments, the belt sandermay alternatively include a belt tensionerthat is configured to adjust the tension of at least one of the pulley belts,. The belt tensionerincludes the drive shaft, the output shaft, the first pulley, the driven shaft, and the second pulley. In some embodiments, the belt tensionermay also include at least one of the motorand the transmission housing. With reference to, the motordrives the drive shaftwhich, in turn, drives the output shaftand the first pulley. The first pulleyis coupled to and drives, for example, the pulley beltand the second pulleyvia the pulley belt. The motoris disposed within a motor housing, which is pivotably coupled within the main housingabout a pinsuch that the motor axisis movable relative to the axis of the driven shaft. Specifically, the motor axisis capable of being moved towards or away from the axis of the driven shaftalong an arcuate path in response to the motor housingpivoting about the pin. If the motor axisis moved towards the axis of the driven shaft, then slack is introduced into the pulley belt. If, on the other hand, the motor axisis moved away from the axis of the driven shaft, then slack is removed and the pulley beltis tensioned. When the motor housingis pivoted about the pinto the desired location, the motor housingis fixed into position via a fastener. In the illustrated embodiment, the motor housingincludes a motor bracketextending away from the motor housingthat receives the fastener. In some embodiments, the motor housingis fixed into position by rigidly interconnecting the motor housingand a bracketof the second pulleyvia the fastener. Although not illustrated, the belt tensionermay also be employed for tensioning the pulley belt. Also not illustrated, the belt tensionermay include a handle or actuator disposed outside the main housingso that a user can manipulate the handle or actuator to adjust the distance between the first pulleyand the second pulley.

As illustrated in, the belt sandermay also include a vibration dampening system. In some embodiments, the vibration dampening systemmay be in addition to the belt tensioner,, or replace the belt tensioner,altogether. The vibration dampening systemincludes a plurality of wave disruptors,disposed adjacent the pulley beltand coupled to the main frame. The wave disruptors,are configured to cancel or disrupt any waves in the pulley beltthat form as a result of vibration in the belt sander. In the illustrated embodiment of, the first wave disruptoris positioned adjacent the first pulley, whereas the second wave disruptoris positioned adjacent the second pulley. Furthermore, the first wave disruptoris disposed adjacent a lower runof the pulley belt, whereas the second wave disruptoris disposed adjacent an upper runof the pully belt. Additionally, each wave disruptor,is positioned away from the outer periphery of the pulley beltto avoid contact with the pulley belt. Specifically, the first and second wave disruptors,are positioned a small distance away from the lower runand the upper run, respectively, thereby defining a first air gapbetween the first wave disruptorand the lower run, and defining a second air gapbetween the second wave disruptorand the upper run. In other words, the first and second wave disruptors,are not in immediate contact with the pulley beltwhen the lower and upper runs,are traveling along their respective straight-line paths,. The air gaps,are intended to avoid excessive rubbing and heat generation between the pulley beltand the wave disruptors,, resulting in increased lifespan of the pulley belt. Although the vibration dampening systemof the illustrated embodiment is disposed adjacent the pulley belt, in other embodiments, the vibration dampening systemmay also be incorporated adjacent the pulley belt.

The wave disruptoris only capable of engaging the lower runat a single contact point. Likewise, the wave disruptoris only capable of contacting the upper runat a single contact point.

During operation, the lower runand the upper runtravel along the respective straight-line paths,between the first pulleyand the second pulley. Specifically, the lower runtravels from the first pulleyto the second pulleyalong the straight-line path, while the upper runtravels from the second pulleyto the first pulleyalong the straight-line path. In some instances, however, the pulley beltmay begin to oscillate or vibrate, such that the lower runand the upper runno longer travel along the straight-line paths,. Rather, the lower runand the upper runmay begin to form waves (e.g., sinusoidal wave forms) between the first and second pulley,. These oscillations or waves of the pulley beltcan cause unwanted damage and wear to the pulley beltand may reduce the lifespan of the pulley belt. When a single oscillation (e.g., wave) of the lower runreaches an amplitude (i.e., perpendicular height from the straight-line pathto the crest of the wave) equivalent to the first air gap, the first wave disruptoris capable of contacting the lower run, thereby interrupting the wave so the lower runcan travel along the straight-line pathagain. Additionally, when the oscillation (e.g., wave) of the upper runreaches an amplitude (i.e., perpendicular height from straight-line pathto the crest of the wave) equivalent to the second air gap, the second wave disruptorcontacts the upper run, thereby interrupting the wave so the upper runcan travel along the straight-line pathagain. Therefore, the vibration dampening systemis engageable with the pulley beltto inhibit oscillations within the pulley beltand maintain the pulley belttraveling along the straight-line paths,to increase the lifespan of the pulley belt.

In the illustrated embodiment of, the first and second wave disruptors,are first and second pins, respectively. Each pin is merely a cylindrical pin that is press-fit into the frame, such that the pin is a stationary component that does not rotate. The pins may alternatively be another type of mechanical component. For example,illustrates that the wave disruptors,are first and second bearings, respectively. Each bearingis disposed on a shaft, allowing the bearingto rotate when the pulley beltcontacts the bearing. The bearingcan reduce friction, and therefore, increase the lifespan of the pulley belt. Still, in further embodiments, the wave disruptors,may alternatively be bushings, ceramic rollers, or other similar type of mechanical component.

With reference to, the dust bagis removably coupled to the outletof the shroud. Specifically, the dust bagincludes a conduit inletand a quick-disconnect mechanismthat connects with the outletto secure the dust bagonto the belt sander. The conduit inletfits over the outlet(e.g., press fit, slip fit, etc.) while the quick-disconnect mechanismis abutted with a shoulderof the outlet. The shoulderis annularly disposed around and extends away from the outlet, allowing the latchto overlap with the shoulderregardless of the orientation of the dust bag.

The quick-disconnect mechanismincludes a latchthat is biased towards the shouldervia a compression spring. In other embodiments, the springis a torsional spring, a tension spring, or another type of spring. When the latchoverlaps the shoulder, the dust bagis inhibited from inadvertent removal from the belt sander. A user, however, can pivot the latchaway from the shoulder(as represented by broken lines of) by depressing a buttonagainst the bias of the spring, causing the latchto be spaced away from the shoulderand permitting removal of the dust bagfrom the outlet. In other embodiments, the latchis an elastic body (e.g., a snap latch) that is capable of elastic deformation as the latchslides over the shoulderto permit attaching and removing the dust bagto the belt sander. Once the dust bagis removed from the belt sander, a user may empty the contents of the dust baginto a waste receptacle, as described in further detail below.

With reference to, the dust bagfurther includes a zipperfor allowing access into the dust bagand removal of dust and debris. The dust bagis approximately rectangular in shape with the zipperextending along the full length of two perpendicular edgesof the dust bag. The other two edgesare sewn closed with the conduit inletextending along and supporting the edgeThe conduit inletalso provides structure to the dust bagso the dust bagdoes not collapse and clog airflow during operation. With the zipperextending along the full length of the edgesdust and debris within the dust bagcan be quickly emptied and disposed in a waste receptacle, leaving behind minimal debris in the corners of the dust bagwithout heavy shaking of the dust bag. Although the zipperof the illustrated embodiment is a single zipper that extends along edges bothin other embodiments, multiple zippers may alternatively be used that each extend along the respective edges.

With reference to, the dust bagfurther includes a flapof extra fabric disposed along the zipper. Specifically, the flapis disposed on the inside of the dust bagand shields the zipperfrom dust particles and debris that can otherwise escape through the teeth of the zipper, causing the zipperto clog and jam. As such, the flapextends at least along the entire length Lof the zipper, as well as extends at least the entire width Wof the zipper. In fact, a length Lof the flapis longer than the length Lof the zipper and a width Wof the flapis wider than the width Wof the zipper. Thus, for debris to escape through the zipper, the debris must first navigate around the flapand through the teeth of the zipper. The flapinhibits dust particles from escaping the dust bagand reduces the likelihood that the zipperwill clog from a buildup of dust particles between the teeth of the zipper.

With reference to, the belt sanderfurther includes a wiring bridgethat conducts electrical current across a joint() between the clamshell halvesTo provide some background, the routing of wires in tools and other devices is often distributed throughout both clamshell halves. Oftentimes, some wire routing is required to span across the separate clamshell halvesin order to electrically connect all components within the tool or device. So, a wire is used to span across the joint between the two clamshell halves, resulting in blind wire routing during assembly and possible inadvertent damage to the wire or other components.

With continued reference to, the clamshell halfincludes an electrical processorwith a first set of wiresextending therefrom to transport electrical current and signals to/from various components of the belt sander(e.g., motor, battery pack, trigger, first light, etc.). The other clamshell halfincludes a second set of wiresthat are capable of electrically communicating with the first set of wires() and other components coupled to the clamshell half(e.g., second light, etc.). The wiring bridgeincludes a first compression springand a second compression springthat each extend beyond the clamshell halfand capable of spanning across the jointbetween the clamshell halvesAs shown in, the first springis seated within the clamshell halfagainst the wire(e.g., via a wire terminal, as shown) and the second springis seated within the clamshell halfagainst the wire(e.g., via a wire terminal, as shown). In this embodiment, the springsare parallel and have the same diameter and length, but in other embodiments, the springsmay alternatively be coaxial with different diameters and lengths.

With reference to, the wiring bridgeelectrically connects wiresandtogether and separately electrically connects wiresandtogether. Specifically, compression springis compressed between and electrically connects wiresandwhile compression springis compressed between and electrically connects wiresandas the clamshell halvesare coupled together. The compression springsserve as electrical conductors between the first set of wiresand the second set of wiressuch that the wiring bridgeis composed of an electrically conductive material. When the clamshell halvesare coupled, the compression springsare compressed against wiresrespectively, to ensure that contact is maintained, and electrical connection is not inadvertently interrupted. Although the wiring bridgeof the illustrated embodiment is comprised of a set of compression springs, in other embodiments, the wiring bridgemay alternatively be comprised of a set of leaf springs or other type of elastic, conductive bodies.

With reference to, the platenincludes a front edgeadjacent the driven wheel, a rear edgeadjacent the drive wheel, a bottom sidethat is configured to be in a facing relationship to a workpiece, and a top sidethat is disposed opposite the bottom side. The top side, in particular, is in a facing relationship to the motor. The platen attachmentis removably coupled to the platenand extends between the front and rear edges,on the bottom sideof the platen. In the illustrated embodiment, a nitride surface coating exists on the platen attachmentto decrease the coefficient of friction between the platen attachmentand the sanding belt. In some embodiments, the platen attachmentis composed of 1080 steel.

With reference to, the platen attachmentincludes a first lipthat is configured to bend around the front edgeof the platen. That is, the platen attachmentextends along the bottom sideof the platenand curls around the front edgeto the top sideof the platen. The platen attachmentincludes a plurality of slotsdisposed along the first lipthat are configured to correspondingly receive a plurality of pinsdisposed on the top sideof the platen. The plurality of slotsalign with the plurality of pins, which are evenly spaced apart along the top sideof the platenin a direction parallel to the driven wheel axis. The plurality of pinsare not accessible by a user unless the belt sanderis disassembled. The plurality of slotsare L-shaped such that one leg of the slotsextends along a direction perpendicular to the driven wheel axisand another leg of the slotsextends along a direction parallel to the driven wheel axis. The L-shape of the slotsassists with assembly of the platen attachment, as described in further detail below. In the illustrated embodiment, there are four slotsand four pins, while in other embodiments, there may alternatively be more or fewer than four slotsand corresponding pins. Although the illustrated embodiment incorporates the plurality of pins, in other embodiment, the pinsmay alternatively be fasteners, screws, or the like threaded into the platen.

With continued reference to, the platen attachmentfurther includes a tabdisposed on the first lip. The tabextends downward from the top sidetoward the bottom sideof the platen. The tabis configured to receive a fastener() that threads into a sidewallof the platento further couple the platen attachmentto the platen, as described in further detail below.

With reference to, the platen attachmentfurther includes a second lipthat is disposed adjacent the bottom sideand the rear edgeof the platen. In the illustrated embodiment, the second lipbends along a corresponding bend of rear edgeof the platen. The second lipbends along a large radius and extends along a path that is tangential to the radius of the drive wheel. As such, the sanding beltand the second lipextend along parallel paths when the sanding beltno longer engages a workpiece. The second lipdecreases wear rates of the sanding beltand decreases temperature generation between the platen attachmentand the sanding belt.

illustrates a second lip′ in accordance with another embodiment of the platen attachment. Here, the second lip′ bends along a continuous arc defining a constant radius. Specifically, the second lip′ extends beyond the rear edgeof the platenand bends above at least a portion of the bottom sideof the platen. A single line may extend between the second lip′ and the drive wheelthat is tangential to both the second lip′ and the drive wheel. The second lip′ decreases wear rates of the sanding beltand decreases temperature generation between the platen attachmentand the sanding belt.

During assembly of the platen attachmentto the platen, a user simply engages the platen attachmentwith the bottom sideof the platen, where the first lipis disposed forward of the front edge, as shown in. At this point, the user aligns the plurality of slotswith the plurality of pinsand slides the platen attachmentrearward towards the drive wheel(). As a result, the plurality of pinsare received within the leg of slotsthat extends perpendicular to the driven wheel axis(). Subsequently, a user slides the platen attachmentin a direction parallel to the drive wheel axis, such that the plurality of pinsare received within the leg of the slotsthat extends parallel to the driven wheel axis. Now, the tababuts the sidewallof the platen, where the fastenercan be threaded into the sidewallof the platento rigidly couple the platen attachmentto the platen. In other words, the platen attachmentis inhibited from moving relative to the platen, until the fasteneris removed.

With reference to, the belt sandermay further include a wear skidremovably coupled to the rear edgeof the platen. Specifically, the wear skidprotrudes beyond the platen attachmentand extends into the path of the sanding beltto provide a more gradual transition to the sanding beltbetween the platen attachmentand the drive wheel. As a result, the sanding beltis prevented from rubbing against the rear edgeof the platen, which may otherwise occur in absence of the wear skid, which may cause premature wear of the sanding belt.

With continued reference to, the wear skiddefines a continuous arc defining a constant radius and extends across the entire width of the platen. The wear skidis coupled to an enlarged headof the platen. The enlarged headincludes a notchto facilitate assembly of the wear skidonto the enlarged headand facilitate heat transfer away from the wear skid. In some embodiments, the wear skidis composed of 1080 steel and includes the nitride surface coating to decrease the coefficient of friction between the wear skidand the sanding belt. In other embodiments, the wear skidmay alternatively be composed of a ceramic material. Although not illustrated, the wear skidmay alternatively be a rolling element that rotates in response to engagement with the sanding beltas the sanding beltis being driven.