POWER TOOL HAVING TOOL-FREE ATTACHMENT SYSTEM

The present invention provides a grinder including a housing, a drive assembly within the housing including an electric motor having a motor shaft, and an output spindle coupled to the motor shaft for rotatably driving a grinding tool. The grinder further includes a tool-free attachment mechanism for selectively mounting the grinding tool to the output spindle for co-rotation therewith including a flange nut threaded to the output spindle, and a backing flange axially movable along the output spindle between a first position, in which a space exists to position the grinding tool between the flange nut and the backing flange, and a second position, in which the grinding tool is clamped between the backing flange and the flange nut.

FIELD OF THE INVENTION

The present invention relates to power tools including tool-free attachment systems, and more particularly to grinders including tool-free attachment systems.

BACKGROUND OF THE INVENTION

Typically, grinders include a motor-driven drive shaft for rotatably driving an output spindle and a grinding tool rotatably coupled to the output spindle. The grinding tool can be coupled to the output spindle in a variety of different ways, for example, threading a nut onto an outside threaded portion of the spindle to retain the grinding tool on the spindle, or threading a fastener into an interior portion of the spindle to fasten the grinding tool on the spindle. However, many of these options are cumbersome, especially if the user is constantly changing grinding tools, and can require the use of outside tools (i.e., a wrench) that a user may not have readily available.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, a grinder including a housing, a drive assembly within the housing including an electric motor having a motor shaft, and an output spindle coupled to the motor shaft for rotatably driving a grinding tool. The grinder further includes a tool-free attachment mechanism for selectively mounting the grinding tool to the output spindle for co-rotation therewith including a flange nut threaded to the output spindle, and a backing flange axially movable along the output spindle between a first position, in which a space exists to position the grinding tool between the flange nut and the backing flange, and a second position, in which the grinding tool is clamped between the backing flange and the flange nut.

The present invention provides, in another aspect, a grinder including a housing, a drive assembly within the housing including an electric motor having a motor shaft, and a hollow output spindle coupled to the motor shaft for rotatably driving a grinding tool having a backing flange portion at one end thereof. The grinder further includes a tool-free attachment mechanism for selectively mounting the grinding tool to the output spindle for co-rotation therewith including a clamping shaft extending through the spindle having a flange nut portion and a stem portion extending from the flange nut portion, and a handle. The handle is pivotably coupled to the housing between a release position, in which the flange nut portion is displaced from the backing flange portion to create a space for mounting the grinding tool between the flange nut portion and the backing flange portion, and a clamped position, in which the grinding tool is clamped between the backing flange portion and the flange nut portion.

The present invention provides, in yet still another aspect, a grinder including a housing, a drive assembly within the housing including an electric motor having a motor shaft, and a hollow output spindle coupled to the motor shaft for rotatably driving a grinding tool. The grinder further includes a tool-free attachment mechanism for selectively fastening the grinding tool to the lower portion of the output spindle including a flange nut affixed adjacent an end of the output spindle, an intra flange adjacent the flange nut and configured to rotate relative to the spindle, a backing flange that fits at least partially over the intra flange, wherein the backing flange is biased toward the flange nut by a spring, wherein the intra flange includes a structure that at least partially nests in the backing flange and wherein the intra flange is rotatable between a locked position in which the ramp structure fits into the ramp groove and the backing flange is biased toward the flange nut to lock the grinding tool on the spindle and an unlocked position in which the ramp structure is moved out of the ramp groove and lifts the backing flange away from the flange nut and compresses the spring to unlock the grinding tool from the spindle.

In some embodiments of the grinder, the grinder further includes a battery receptacle, and a battery pack selectively electrically coupled to the battery receptacle for providing electrical power to the motor.

In some embodiments of the grinder, the flange nut and the backing flange cooperatively define a first mounting arrangement, and the grinding tool includes a second mounting arrangement configured to receive therethrough the first mounting arrangement of the flange nut and the backing flange.

In some embodiments of the grinder, when the grinding tool is mounted to the spindle, the grinding tool is rotated to misalign the second mounting arrangement from the first mounting arrangement on the flange nut, and to align the second mounting arrangement with the first mounting arrangement on the backing flange to rotationally lock the grinding tool on the spindle.

DETAILED DESCRIPTION

FIG.1illustrates a power tool such as a grinder10. The grinder10includes a housing14including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing18coupled to the housing14. The housing14also includes a handle portion15extending rearward from the motor housing portion, and a battery receptacle (not shown) for selectively receiving a battery pack for selectively electrically powering the motor. The grinder10further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing18substantially encloses and supports a portion of a drive assembly20. The drive assembly20includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear19rotatably driven by the drive gear, and a spindle26coupled for co-rotation with the driven gear19. The grinder10further includes a tool-free attachment mechanism30for selectively mounting a grinding tool60(e.g., a grinding disc) on a lower portion of the spindle26.

The gear case housing18includes an upper gear case (not shown) and a lower gear case22attached to the upper gear case and supports at least a portion of the drive assembly20. The lower gear case22includes a bearing34for rotatably supporting a portion of the spindle26, and a blade guard45for enclosing the grinding tool60.

With respect toFIGS.1-5B, the tool-free attachment mechanism30includes a spacer42rotatably coupled to the spindle26, a spindle flange44supported on a plurality of shoulders27(FIG.2) of the spindle26, and a spring38provided between the spacer42and the flange44configured to bias the flange44downward from the frame of reference ofFIG.1. The tool-free attachment mechanism30further includes a backing flange48keyed to the spindle flange44for co-rotation with the backing flange48, and a flange nut56threaded onto the spindle26until it abuts a retaining ring52positioned between the flange nut56and the backing flange48. Both the backing flange48and the flange nut56have a first and second mounting arrangements49,57(FIGS.3-4: e.g., torque features), respectively, that interface with the grinding tool60during operation and installation. The first mounting arrangement49includes a plurality of axially extending protrusions and the second mounting arrangement57includes a plurality of radially extending protrusions that are configured to misalign with and be received between the plurality of axially extending protrusions of the first mounting arrangement49.

FIG.5illustrates the grinding tool60for use with the grinder10. The grinding tool60includes a center aperture62having a plurality of recesses61sized such that the recesses61align with first mounting arrangement49of the backing flange48.

With reference toFIGS.1,5, and6A-B, to install the grinding tool60, a user lifts the backing flange48upward along the spindle26, which compresses the spring38and creates a space64between the backing flange48and the flange nut56for the user to install the grinding tool60. Next, the user aligns the aperture62of the grinding tool60such that the recesses61of the tool60align with the second mounting arrangement57of the flange nut56and moves the grinding tool60over the flange nut56and into the space64(FIG.6A). Once the grinding tool60is in the space64, while continually lifting the backing flange48, the user rotates (e.g., about 45 degrees) the grinding tool60relative to the backing flange48in order to misalign the first and second mounting arrangements57,49of both the flange nut56and the backing flange48, respectively, to rotationally lock the grinding tool60for co-rotation with the spindle26(FIG.6B). Lastly, to axially retain the grinding tool60on the spindle26, the user releases the backing flange48, permitting the spring38to rebound and push the backing flange48and the grinding tool60toward the flange nut56to axially secure the grinding tool60within the space64. To remove the grinding tool60, the user can perform the abovementioned steps in reverse.

FIG.7illustrates a grinder110in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “100”. The grinder110includes a housing114including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing118coupled to the housing114. The housing114also includes a handle portion115extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor. The grinder110further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing118substantially encloses and supports a portion of a drive assembly120. The drive assembly120includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear119rotatably driven by the drive gear, and a hollow spindle126coupled for co-rotation with the driven gear119. The grinder110further includes a tool-free attachment mechanism130for selectively mounting a grinding tool160on a lower portion128of the spindle126.

The gear case housing118further includes an upper gear case (not shown) and a lower gear case122attached to the upper gear case and supports at least a portion of the drive assembly120. The lower gear case122includes a bearing134for rotatably supporting a portion of the spindle126, a spacer142for supporting the lower portion128of the spindle126, and a blade guard145for enclosing the grinding tool160.

With respect toFIGS.7-9, the tool-free attachment mechanism130includes a clamping shaft180extending through the hollow spindle126with a flange nut portion156integrated with the shaft180adjacent a lower end128of the spindle126, and a stem portion176extending from the flange nut portion156. The clamping shaft180is configured to be keyed to the spindle126with flats for co-rotation with the spindle126. The mechanism130further includes a cam handle172pivotably supported on the stem portion176of the clamping shaft180via a rotatable joint connection169such that the handle172will not co-rotate with the clamping shaft180or the spindle126during operation of the grinder110. The cam handle172is configured to impart an axial force onto the stem portion176of the clamping shaft180to axially move the clamping shaft180within the spindle126. The attachment mechanism130further includes a backing flange portion148integrated with the lower end128of the spindle126, and a spring138positioned within the opening in the spindle126between the lower end128of the spindle126and the flange nut portion156for biasing the flange nut portion156in a downward direction from the frame of reference ofFIG.7.

With continued reference toFIGS.7-9, both the backing flange portion148(FIG.9) of the spindle126and the flange nut portion156of the clamping shaft180(FIG.8) have first and second mounting arrangements149,157(FIGS.8-9); e.g., torque features), respectively, that interface with the grinding tool160during operation and installation. The first mounting arrangement149includes a plurality of axially extending protrusions and the second mounting arrangement157includes a plurality of radially extending protrusions that are configured to misalign with and be received between the plurality of axially extending protrusions of the first mounting arrangement149. The grinding tool60(FIG.5) is oriented so that the center aperture62and the plurality of recesses61align with second mounting arrangement157of the flange nut portion156.

With reference toFIGS.7and10A-10C, to install the grinding tool160, a user pivots the clamp handle172upward (FIG.7), which imparts a force onto the stem portion176of the clamping shaft180and moves the shaft180downward against the bias of the spring138, thereby pushing the flange nut156portion of the shaft180away from the backing flange148portion of spindle126to create an axial space164for the user to install the grinding tool160. Next, the user aligns the aperture62of the grinding tool160so the recesses61of the tool160align with the second mounting arrangement157of the flange nut156and moves the grinding tool160over the flange nut156and into the space164(FIG.10A). Once the grinding tool160is in the space164, the user rotates (e.g., about 45 degrees) the grinding tool160about the backing flange148in order to misalign the first and second mounting arrangements157,149of both the flange nut156and the backing flange148, respectively, to rotationally lock the grinding tool160for co-rotation with the spindle126(FIG.10B). Lastly, to axially retain the grinding tool160on the spindle126, the user pivots the clamp handle172downward (FIG.10C), which pulls the flange nut portion156of the clamping shaft180toward the spindle126against the bias of the spring138, and axially secures the grinding tool160within the space164. To remove the grinding tool160, the user can perform the abovementioned steps in reverse.

FIG.11illustrates a grinder210in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “200”. The grinder210includes a housing214including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing218coupled to the housing214. The housing214also includes a handle portion215extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor. The grinder210further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing218substantially encloses and supports a portion of a drive assembly220. The drive assembly220includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear219rotatably driven by the drive gear, and a hollow spindle226coupled for co-rotation with the driven gear219. The grinder210further includes a tool-free attachment mechanism230for selectively mounting a grinding tool260on a lower portion228of the spindle226.

The gear case housing218further includes an upper gear case (not shown) and a lower gear case222attached to the upper gear case and supports at least a portion of the drive assembly220. The lower gear case222includes a bearing234for rotatably supporting a portion of the spindle226, a spacer242for supporting the lower portion228of the spindle226, and a blade guard245for enclosing the grinding tool260.

With respect toFIGS.11-14C, the tool-free attachment mechanism230includes a clamping shaft280extending through the hollow spindle226with a backing flange portion248integrated with the shaft280adjacent a lower end228of the spindle226, and a stem portion276extending from the backing flange portion248. The clamping shaft280is configured to be keyed to the spindle226with flats for co-rotation with the spindle226. The attachment mechanism230further includes a cam handle272pivotably supported on the stem portion276of the clamping shaft280via a rotatable joint connection269such that the handle272will not co-rotate with the clamping shaft280or the spindle226during operation of the grinder210. The cam handle272is configured to impart an axial force onto the stem portion276of the clamping shaft280to axially move the clamping shaft280within the spindle226. The attachment mechanism230further includes a flange nut256threaded within the lower end228of the spindle226for co-rotation with the spindle226, and a spring238positioned within the opening in the spindle226between the lower end228of the spindle226and the backing flange portion248for biasing the backing flange portion248in downward direction from the frame of reference ofFIG.11.

With reference toFIGS.11-13, both the backing flange portion248(FIG.12) of the clamping shaft280and the flange nut256(FIG.13) have first and second mounting arrangements257,249(FIGS.12-13: e.g., torque features), respectively, that interface with the grinding tool260during operation and installation. The first mounting arrangement249includes a plurality of axially extending protrusions and the second mounting arrangement257includes a plurality of radially extending protrusions262and apertures259adjacent the protrusions262. The protrusions of the first mounting arrangement249are configured to misalign with the protrusions262of the second mounting arrangement and extend into the apertures259.

The grinding tool60(FIG.5) is oriented so that the center aperture62and the plurality of recesses61align with plurality of protrusions262of the first mounting arrangement257of the flange nut256.

With reference toFIGS.11and14A-14C, to install the grinding tool260, a user pivots the clamp handle272upward (FIG.11), which pulls the clamping shaft280upward against the bias of the spring238, thereby pulling the backing flange portion248of the shaft280upward to create an axial space264between the flange nut256for the user to install the grinding tool260. Next, the user aligns the aperture62of the grinding tool260so the recesses61of the tool260align with the first mounting arrangement257of the flange nut256and moves the grinding tool60over the flange nut256and into the space264(FIG.14A). Once the grinding tool60is in the space264, the user rotates (e.g., about 45 degrees) the grinding tool260relative to the backing flange portion248in order misalign the first and second mounting arrangements257,249of the flange nut256and backing flange portion248, while simultaneously aligning the axial protrusions of the first mounting arrangement249of the backing flange248with the apertures259of the flange nut256such that the first mounting arrangement249is maintained in-line, but above the apertures259(FIG.14B). Lastly, to lock the grinding tool axially and rotationally260with the spindle226, the user pivots the clamp handle272downward (FIG.14C), which releases the clamping shaft280and allows the shaft280to move downward under the bias of the rebounding spring238, moving the first mounting arrangement249of the backing flange portion248into their respective apertures259of the flange nut256to secure the grinding tool260within the space264. To remove the grinding tool260, the user can perform the abovementioned steps in reverse.

FIG.15illustrates a grinder310in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “300”. The grinder310includes a housing314including a motor housing portion in which an electric motor315having a motor shaft316is located, and a gear case318coupled to the housing314. The housing314also includes a handle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor315. The grinder310further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor315. The gear case318substantially encloses and supports a portion of a drive assembly320. The drive assembly320includes the motor315, a drive gear317rotatably coupled to the motor shaft316for receiving torque from the motor315, a driven gear319rotatably driven by the drive gear317, and a hollow spindle326coupled for co-rotation with the driven gear319. The grinder310further includes a tool-free attachment mechanism330for selectively mounting a grinding tool360on a lower portion328of the spindle326.

The gear case318further includes an upper gear case321and a lower gear case322attached to the upper gear case321and supports at least a portion of the drive assembly320. The lower gear case322includes a bearing334(e.g., a needle bearing) for rotatably supporting a portion of the spindle326, and a blade guard345for enclosing the grinding tool360.

With continued reference toFIGS.15and16, the tool-free attachment mechanism330includes a clamping shaft380extending through the hollow spindle326for co-rotation with the spindle326, a plurality of clamping members382integrated with a lower portion of the shaft380adjacent the lower portion328of the spindle326, a clamp pin390extending into the spindle326having a shaft portion394for being selectively retained by the clamping members382, and a collar396affixed to the spindle326configured to engage and selectively bias the clamping members382inward toward one another for grasping the shaft portion394of the clamp pin390. The attachment mechanism330further includes a thrust plate377axially affixed to the clamping shaft380, a compression spring338located between the thrust plate377and the collar396for maintaining the collar396in engagement with the clamping members382, and a backing flange348located on the lower portion328of the spindle326having a first mounting arrangement349(FIG.16) that interfaces with the grinding tool360during operation and installation. The first mounting arrangement349includes an axially extending protrusion351configured to pilot into the center aperture62(FIG.5) of the grinding tool360.

The attachment mechanism330further includes a cam handle372pivotably supported on the gear case318via a rotatable joint connection369such that the handle372will not co-rotate with the clamping shaft380or the spindle326during operation of the grinder310. The cam handle372is configured to impart an axial force onto a stem portion376of the clamping shaft380to axially move the clamping shaft380within the spindle326.

With reference toFIGS.15and16, to install the grinding tool360, a user pivots the clamp handle372upward, which imparts a force onto the stem portion376of the clamping shaft380and moves the shaft380and the attached thrust plate377downward against the bias of the spring338, thereby compressing the spring338against the collar396. This opens a gap between the collar396and the clamping members382such that the members382slide down the collar396and move into the axial space383in the spindle326. By moving into the axial space383, the clamping members382are permitted to move outward and unclamp from the shaft portion394of the clamp pin390. Next, with the shaft portion394unclamped, the user can remove the clamp pin390from the spindle326so they can attach the grinding tool360to the grinder310. Once the clamp pin390is removed, the user aligns the aperture62of the grinding tool360so that the axially extending protrusion351on the backing flange348pilots into the aperture62. Once the grinding tool360is piloted onto the backing flange348, the user re-inserts the clamp pin390so that the shaft portion394extends into the spindle326through both the aperture62of the grinding tool360and the backing flange348. Lastly, to axially and rotationally retain the grinding tool360on the spindle326, while continually holding the clamp pin390in the spindle326, the user pivots the clamp handle372downward (into the position shown inFIG.15), which moves the clamping shaft380and thrust plate377upward with the rebounding spring338, thereby closing the gap between the collar396and the clamping members382and allowing the clamping members382to ride up the collar396as they are moving out of the space383. As the clamping members382ride up the collar396, the clamping members382are bent inward to engage and retain the shaft portion394of the clamp pin390within the spindle326, which also applies a clamping force between the clamp pin390and the backing flange348to axially secure the grinding tool360. To remove the grinding tool360, the user can perform the abovementioned steps in reverse.

FIG.17illustrates a grinder410in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “400”. The grinder410includes a housing414including a motor housing portion in which an electric motor415having a motor shaft416is located, and a gear case418coupled to the housing414. The housing414also includes a handle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor415. The grinder410further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor415. The gear case418substantially encloses and supports a portion of a drive assembly420. The drive assembly420includes the motor415, a drive gear417rotatably coupled to the motor shaft416for receiving torque from the motor415, a driven gear419rotatably driven by the drive gear417, and a hollow spindle426coupled for co-rotation with the driven gear419. The grinder410further includes a tool-free attachment mechanism430for selectively mounting a grinding tool460on a lower portion428of the spindle426.

The gear case418further includes an upper gear case421and a lower gear case422attached to the upper gear case421and supports at least a portion of the drive assembly420. The upper gear case421includes a spindle lock488for being selectively received within an aperture487on an upper portion427of the spindle426for rotatably locking the spindle426when the user is changing the grinding tool460. The lower gear case422includes a bearing434(e.g., a needle bearing) for rotatably supporting a portion of the spindle426, and a blade guard445for enclosing the grinding tool460.

With continued reference toFIG.17, the tool-free attachment mechanism430) includes a clamping shaft480extending through the hollow spindle426for co-rotation with the spindle426, a retaining ring478axially affixed to the clamping shaft480adjacent the upper portion427of the spindle426, a thrust plate477supported on the clamping shaft480) by the retaining ring478, and a compression spring438provided between the thrust plate477and the lower portion428of the spindle426configured to bias the thrust plate477and clamping shaft480upward from the frame of reference ofFIG.17. The tool-free attachment mechanism430further includes a backing flange448coupled to the lower portion428of the spindle426, and a flange nut456threaded onto a threaded portion485of the spindle426until it abuts the grinding tool460. The backing flange448is similar to the backing flange348of the grinder310such that the backing flange448includes the first mounting arrangement349(FIG.16) configured to interface with the grinding tool460during operation and installation. The first mounting arrangement349includes the axially extending protrusion351configured to pilot into the center aperture62(FIG.5) of the grinding tool460.

The attachment mechanism430further includes a cam handle472pivotably supported on the gear case418via a rotatable joint connection469, such that the handle472will not co-rotate with the clamping shaft480or the spindle426during operation of the grinder410. The cam handle472is configured to impart an axial force onto the stem portion476of the clamping shaft480to axially move the clamping shaft480within the spindle426.

With further reference toFIG.17, to install the grinding tool460, a user pivots the clamp handle472upward, which pushes both the clamping shaft480and the thrust plate477downward against the bias of the spring438, thereby pushing the flange nut456away from the backing flange448creating an axial space between the backing flange448and the flange nut456in which the grinding tool460is installed and held. Next, the user actuates the spindle lock488, which moves the lock488into the aperture487in order to rotationally lock the spindle426and unthreads the flange nut456from the threaded portion485of the clamping shaft480. Once the flange nut456is removed, the user aligns the aperture62of the grinding tool460so that the axially extending protrusion451on the backing flange448pilots into the aperture62. In this position, the grinding tool460is loosely retained on the clamping shaft480allowing the user to simultaneously depress the spindle lock488and thread the flange nut456back onto the clamping shaft480until it abuts the grinding tool460. Lastly, to axially and rotationally lock the grinding tool460with the spindle426, the user pivots the clamp handle472downward (shown inFIG.17), which releases the clamping shaft480and allows the shaft480to move upward under the action of the rebounding compression spring438, moving the flange nut456into engagement with the grinding tool460to impart a clamping force onto the grinding tool460in order to close any axial space between the backing flange448and the flange nut456. To remove the grinding tool460, the user can perform the abovementioned steps in reverse.

FIG.18illustrates another power tool, such as a grinder510. The grinder510includes a housing514including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing518coupled to the housing514. The housing514also includes a handle portion515extending rearward from the motor housing portion, and a battery receptacle (not shown) for selectively receiving a battery pack for selectively electrically powering the motor. The grinder510further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing518substantially encloses and supports a portion of a drive assembly520. The drive assembly520includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear519rotatably driven by the drive gear, and a spindle526coupled for co-rotation with the driven gear519. The grinder510further includes a tool-free attachment mechanism530for selectively mounting a grinding tool560(e.g., a grinding disc) on a lower portion of the spindle526.

The gear case housing518includes an upper gear case (not shown) and a lower gear case522attached to the upper gear case and supports at least a portion of the drive assembly520. The lower gear case522includes a bearing534for rotatably supporting a portion of the spindle526, and a blade guard545for enclosing the grinding tool560.

With respect toFIGS.18-23, the tool-free attachment mechanism530includes a spacer542keyed to a flat region543(FIG.20) and therefore, rotatably coupled to the spindle526, a backing flange544keyed to the flat region543(FIG.20) of the spindle526and supported on a shoulder527(FIG.20) of the spindle526, and a spring538provided between the spacer542and the backing flange544configured to bias the backing flange544downward from the frame of reference ofFIG.18andFIG.19along the flat region543(FIG.20) of the spindle526. It is to be understood that the spacer542and the backing flange544may not move radially relative to the spindle526. The spacer542and the backing flange544rotate with the spindle526. Further, the backing flange544only moves axially along the spindle526. The spring538provides a force to create a clamping load in order to retain the grinding tool560. The spring538is held in place by groove features551,553formed in the spacer542and the backing flange544. It is to be understood that the backing flange544is not removable from the spindle526. Specifically, the backing flange544is prevented from moving too far down the spindle526by the shoulder527. Further, the backing flange544is prevented from moving too far up the spindle526by the lower gear case522.

As shown inFIG.23-25, the tool-free attachment mechanism530further includes a flange nut548pressed onto the spindle526for co-rotation with the spindle526. An intra flange550is disposed on the spindle526adjacent to the flange nut548. The intra flange550is slip fit onto the spindle526and rotates thereon. Both the flange nut548and the intra flange550have a first and second mounting arrangements549,557(FIGS.23-24: e.g., torque features), respectively, that interface with the grinding tool560during operation and installation. The first mounting arrangement549includes a plurality of axially extending protrusions and the second mounting arrangement557includes a plurality of radially extending protrusions that are configured to misalign with and be received similarly shaped recesses formed on the grinding tool560. The flange nut548supports the grinding tool560during operation and the backing flange544fit at least partially over the intra flange550and provides clamping force. As illustrated inFIG.26, the intra flange550includes a ramp structure555that may cooperate with the backing flange544to lift the backing flange544away from the grinding tool560, as shown inFIG.29, and counteract the clamping force of the spring538.

FIG.27illustrates the grinding tool560for use with the grinder510. The grinding tool560includes a center aperture562having a plurality of recesses561sized such that the recesses561align with first mounting arrangement549of the flange nut548.

In order to install the grinding tool560on the spindle526, the aperture562of the grinding tool560is aligned with the protrusions on the flange nut548, as shown inFIG.28. Then, the grinding tool560is slipped over the flange nut548and onto the corresponding protrusions of the intra flange550. In the installation position, as depicted inFIG.29, the ramp structure555holds the backing flange544up and out of contact with the grinding tool560and removes the clamping force of the spring538from the grinding tool560. Once the grinding tool560is on the intra flange550, the arbor lock on the grinder510is engaged to lock the spindle526. Then, the grinding tool560and the intra flange550are rotated approximately forty-five degrees (45°) counterclockwise until the ramp structure555on the intra flange550is aligned with a complementary shaped ramp groove565formed in the backing flange544. Once aligned, the ramp structure555on the intra flange550may nest within the ramp groove565of the backing flange544, as illustrated inFIG.31. With the ramp structure555on the intra flange550nested within the ramp groove565of the backing flange544, the spring538biases the backing flange544into contact with the grinding tool560, as shown inFIG.33. As such, the backing flange544can engage the grinding tool560and provide a clamping force to hold the grinding tool560in place against the flange nut548.

To remove the grinding tool560from the spindle526, the arbor lock is engaged to lock the spindle526. Then, the grinding tool560and the intra flange550are rotated approximately forty-five degrees (45°) clockwise until the ramp structure555on the intra flange550is misaligned with the ramp groove565formed in the backing flange544. As the ramp structure555on the intra flange550rotates out of the ramp groove565, the ramp structure555on the intra flange550lifts the backing flange544away from the grinding tool560to remove the clamping force provided by the spring538, as illustrated inFIG.29. Once the clamping force is removed, the aperture562of the grinding tool560may be re-aligned with the protrusions on the flange nut548and the grinding tool560may be removed from the spindle526.

FIG.34illustrates a grinder610in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “600”. The grinder610includes a housing614including a motor housing portion in which an electric motor615having a motor shaft616is located, and a gear case618coupled to the housing614. The housing614also includes a handle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor615. The grinder610further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor615. The gear case618substantially encloses and supports a portion of a drive assembly620. The drive assembly620includes the motor615, a drive gear617rotatably coupled to the motor shaft616for receiving torque from the motor615, a driven gear619rotatably driven by the drive gear617, and a hollow spindle626coupled for co-rotation with the driven gear619. The grinder610further includes a tool-free attachment mechanism630for selectively mounting a grinding tool660on a lower portion628of the spindle626.

The gear case618further includes an upper gear case621and a lower gear case622attached to the upper gear case621and supports at least a portion of the drive assembly620. The upper gear case621includes a spindle lock688for being selectively received within an aperture687on an upper portion627of the spindle626for rotatably locking the spindle626when the user is changing the grinding tool660. The lower gear case622includes a bearing634(e.g., a needle bearing) for rotatably supporting a portion of the spindle626, and a blade guard645for enclosing the grinding tool660.

With continued reference toFIG.34, the tool-free attachment mechanism630includes a clamping shaft680extending through the hollow spindle626for co-rotation with the spindle626, a retaining ring678axially affixed to the clamping shaft680adjacent the upper portion627of the spindle626, a thrust plate677supported on the clamping shaft680by the retaining ring678, and a compression spring638provided between the thrust plate677and the lower portion628of the spindle626configured to bias the thrust plate677and clamping shaft680upward from the frame of reference ofFIG.34. The tool-free attachment mechanism630further includes a backing flange648coupled to the lower portion628of the spindle626, and a flange bolt656having a head657and a threaded stem658that extends from the head657. The threaded stem658of the flange bolt656is threaded into a threaded bore685formed in the clamping shaft680until the head657of the flange bolt656abuts the grinding tool660. The backing flange648is similar to the backing flange348of the grinder310such that the backing flange648includes the first mounting arrangement349(FIG.16) configured to interface with the grinding tool660during operation and installation. The first mounting arrangement349includes the axially extending protrusion651configured to pilot into the center aperture62(FIG.5) of the grinding tool660.

The attachment mechanism630further includes a cam handle672pivotably supported on the gear case618via a rotatable joint connection669such that the handle672will not co-rotate with the clamping shaft680or the spindle626during operation of the grinder610. The cam handle672is configured to impart an axial force onto the stem portion676of the clamping shaft680to axially move the clamping shaft680within the spindle626.

With further reference toFIG.34, to install the grinding tool660, a user pivots the clamp handle672upward, which pushes both the clamping shaft680and the thrust plate677downward against the bias of the spring638, thereby pushing the flange bolt656away from the backing flange648creating an axial space between the backing flange648and the head657of the flange bolt656in which the grinding tool660is installed and held. Next, the user actuates the spindle lock688, which moves the lock688into the aperture687to rotationally lock the spindle626, and unthreads the flange bolt656from the threaded bore685of the clamping shaft680. Once the flange bolt656is removed, the user aligns the aperture62of the grinding tool660so that the axially extending protrusion651on the backing flange648pilots into the aperture62. In this position, the grinding tool660is loosely retained on the clamping shaft680allowing the user to simultaneously depress the spindle lock688and thread the flange bolt656back into the threaded bore685of the clamping shaft680until the head657of the flange bolt656abuts the grinding tool660. Lastly, to axially and rotationally lock the grinding tool660with the spindle626, the user pivots the clamp handle672downward (shown inFIG.34), which releases the clamping shaft680and allows the shaft680to move upward under the action of the rebounding compression spring638, moving the head657of the flange bolt656into engagement with the grinding tool660to impart a clamping force onto the grinding tool660in order to close any axial space between the backing flange648and the head657of the flange bolt656. To remove the grinding tool660, the user can perform the abovementioned steps in reverse.

FIG.35illustrates a grinder710in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “700”. The grinder710includes a housing714including a motor housing portion in which an electric motor715having a motor shaft716is located, and a gear case718coupled to the housing714. The housing714also includes a handle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor715. The grinder710further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor715. The gear case718substantially encloses and supports a portion of a drive assembly720. The drive assembly720includes the motor715, a drive gear717rotatably coupled to the motor shaft716for receiving torque from the motor715, a driven gear719rotatably driven by the drive gear717, and a hollow spindle726coupled for co-rotation with the driven gear719. The grinder710further includes a tool-free attachment mechanism730for selectively mounting a grinding tool760on a lower portion728of the spindle726.

The gear case718further includes an upper gear case721and a lower gear case722attached to the upper gear case721and supports at least a portion of the drive assembly720. The upper gear case721includes a spindle lock788for being selectively received within an aperture787on an upper portion727of the spindle726for rotatably locking the spindle726when the user is changing the grinding tool760. The lower gear case722includes a bearing734(e.g., a needle bearing) for rotatably supporting a portion of the spindle726, and a blade guard745for enclosing the grinding tool760.

With continued reference toFIG.35, the tool-free attachment mechanism730includes a clamping shaft780extending through the hollow spindle726for co-rotation with the spindle726, a retaining ring778axially affixed to the clamping shaft780adjacent the upper portion727of the spindle726, a thrust plate777supported on the clamping shaft780by the retaining ring778, and a compression spring738provided between the thrust plate777and the lower portion728of the spindle726configured to bias the thrust plate777and clamping shaft780upward from the frame of reference ofFIG.35. The clamping shaft780further includes a straight post781extending in a generally downward direction from the clamping shaft780as illustrated inFIG.35. A ball782is formed on a distal end of the straight post781.

The tool-free attachment mechanism730further includes a backing flange748that is coupled to the lower portion728of the spindle726, and a clamping flange756that is rotatably disposed on the ball782of the clamping shaft780(e.g., the clamping flange756and the ball782define a ball-and-socket joint). The clamping flange756includes a central hub757that is sized and shaped to fit over and at least partially around the ball782to allow the clamping flange756to rotate on the ball782but not disengage or disassemble from the ball782. The clamping flange756also includes a tool engagement portion758that extends radially outward from the central hub757of the clamping flange756. When a grinding tool760is installed on the grinder710, as described below, the grinding tool760may be held in place between the tool engagement portion758of the clamping flange756and the backing flange748. It is to be understood that the backing flange748is similar to the backing flange348of the grinder310such that the backing flange748includes the first mounting arrangement349(FIG.16) configured to interface with the grinding tool760during operation and installation. The first mounting arrangement349includes the axially extending protrusion351configured to pilot into the center aperture62(FIG.5) of the grinding tool760.

FIG.43illustrates another example of a tool-free attachment mechanism730athat is similar to the attachment mechanism730. More specifically, the attachment mechanism730aincludes a clamping shaft780awith a curved post781athat extends in a generally downward direction from the clamping shaft780a. A ball782ais formed on a distal end of the curved post781a. A clamping flange756afits over the ball782ain a manner consistent with what is described relative toFIG.35. The curved post781aallows the clamping flange756ato tilt on the ball782ato a greater degree than it would on the straight post781. This configuration provides additional clearance when installing and removing a grinding tool760afrom the grinder710a, as described in detail below.

Returning toFIG.35, the attachment mechanism730further includes a cam handle772that is pivotably supported on the gear case718via a rotatable joint connection769such that the handle772will not co-rotate with the clamping shaft780or the spindle726during operation of the grinder710. The cam handle772is configured to impart an axial force onto the stem portion776of the clamping shaft780to axially move the clamping shaft780within the spindle726.

To install the grinding tool760, a user pivots the clamp handle772upward, which pushes both the clamping shaft780and the thrust plate777downward against the bias of the spring738, thereby pushing the clamping flange756away from the backing flange748creating an axial space between the backing flange748and the clamping flange756as illustrated inFIG.36. Next, as shown inFIG.36, the user rotates the clamping flange756on the ball782so that the clamping flange756is tilted, or angled, with respect to the backing flange748. The aperture62of the grinding tool760is fitted over a first end of the clamping flange756. Then, as depicted inFIG.37, the grinding tool760is moved toward the straight post781that supports the ball782until the aperture62of the grinding tool760substantially clears the clamping flange756, as shown inFIG.38. Thereafter, the clamping flange756is rotated to a position in which the tool engagement portion758is generally parallel to the grinding tool760, as shown inFIG.39. With reference toFIGS.35,38, and39, the user aligns the aperture62of the grinding tool760so that the axially extending protrusion751on the backing flange748pilots, or otherwise fits, into the aperture62. With reference toFIGS.35and40-42, the user pivots the clamp handle772downward (shown inFIG.35) to axially and rotationally lock the grinding tool760on the spindle726. That is, this movement releases the clamping shaft780and allows the shaft780to move upward due to the bias of the compression spring738, which moves the clamping flange756into engagement with the grinding tool760to impart a clamping force onto the grinding tool760. To remove the grinding tool760, the user can perform the abovementioned steps in reverse.

FIG.44illustrates a grinder810in accordance with another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “800”. The grinder810includes a housing814including a motor housing portion in which an electric motor815having a motor shaft816is located, and a gear case818coupled to the housing814. The housing814also includes a handle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor815. The grinder810further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor815. The gear case818substantially encloses and supports a portion of a drive assembly820. The drive assembly820includes the motor815, a drive gear817rotatably coupled to the motor shaft816for receiving torque from the motor815, a driven gear819rotatably driven by the drive gear817, and a hollow spindle826coupled for co-rotation with the driven gear819. The grinder810further includes a tool-free attachment mechanism830for selectively mounting a grinding tool860on a lower portion828of the spindle826.

The gear case818further includes an upper gear case821and a lower gear case822that is attached to the upper gear case821and supports at least a portion of the drive assembly820. The upper gear case821includes a spindle lock888for being selectively received within an aperture887on an upper portion827of the spindle826for rotatably locking the spindle826when the user is changing the grinding tool860. The lower gear case822includes a bearing834(e.g., a needle bearing) for rotatably supporting a portion of the spindle826, and a blade guard845for enclosing the grinding tool860.

With continued reference toFIG.44, the tool-free attachment mechanism830includes a clamping shaft880extending through the hollow spindle826for co-rotation with the spindle826, a retaining ring878axially affixed to the clamping shaft880adjacent the upper portion827of the spindle826, a thrust plate877supported on the clamping shaft880by the retaining ring878, and a compression spring838provided between the thrust plate877and the lower portion828of the spindle826configured to bias the thrust plate877and clamping shaft880upward from the frame of reference ofFIG.44. The tool-free attachment mechanism830further includes a backing flange848that is coupled to the lower portion828of the spindle826. A flexible cable881extends in a generally downward direction, as illustrated inFIG.44, from a lower end882of the clamping shaft880. A clamping flange856is affixed, or otherwise attached, to a distal end883of the flexible cable881. It is to be understood that the backing flange848is similar to the backing flange348of the grinder310such that the backing flange848includes the first mounting arrangement349(FIG.16) configured to interface with the grinding tool860during operation and installation. The first mounting arrangement349includes the axially extending protrusion351configured to pilot into the center aperture62(FIG.5) of the grinding tool860.

The attachment mechanism830further includes a cam handle872that is pivotably supported on the gear case818via a rotatable joint connection869such that the handle872will not co-rotate with the clamping shaft880or the spindle826during operation of the grinder810. The cam handle872is configured to impart an axial force onto the stem portion876of the clamping shaft880to axially move the clamping shaft880within the spindle826.

With further reference toFIG.44, to install the grinding tool860, a user pivots the clamp handle872upward, which pushes both the clamping shaft880and the thrust plate877downward against the bias of the spring838, thereby pushing the clamping flange856away from the backing flange848creating an axial space between the backing flange848and the clamping flange856as shown. Next, the user rotates the clamping flange856via the flexible cable881so that the clamping flange856is tilted, or angled, with respect to the backing flange848. The grinding tool860is fitted over the clamping flange856via the aperture62. Then, the grinding tool860is moved upward along the flexible cable881until the clamp flange856is fitted through the aperture62. Thereafter, the clamping flange856is rotated back into a position in which the clamping flange856is parallel to the grinding tool860and the user aligns the aperture62of the grinding tool860so that the axially extending protrusion851on the backing flange848pilots, or otherwise fits, into the aperture62. Finally, to axially and rotationally lock the grinding tool860with the spindle826, the user pivots the clamp handle872downward to the position depicted inFIG.44, which releases the clamping shaft880and allows the shaft880and flexible cable881to move upward under the action of the rebounding compression spring838, moving the clamping flange856into engagement with the grinding tool860to impart a clamping force onto the grinding tool860in order to close any axial space between the backing flange848and the clamping flange856. To remove the grinding tool860, the user can perform the abovementioned steps in reverse.

FIG.45illustrates a grinder910in accordance with yet another embodiment of the invention. Like components and features of the grinder10ofFIGS.1-6Bwill be used plus “900”. The grinder910includes a housing914including a motor housing portion in which an electric motor915having a motor shaft916is located, and a gear case918coupled to the housing914. The housing914also includes a handle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor915. The grinder910further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor915. The gear case918substantially encloses and supports a portion of a drive assembly920. The drive assembly920includes the motor915, a drive gear917rotatably coupled to the motor shaft916for receiving torque from the motor915, a driven gear919rotatably driven by the drive gear917, and a hollow spindle926coupled for co-rotation with the driven gear919. The grinder910further includes a tool-free attachment mechanism930for selectively mounting a grinding tool960on a lower portion928of the spindle926.

The gear case918further includes an upper gear case921and a lower gear case922attached to the upper gear case921and supports at least a portion of the drive assembly920. The upper gear case921includes a spindle lock988for being selectively received within an aperture987on an upper portion927of the spindle926for rotatably locking the spindle926when the user is changing the grinding tool960. The lower gear case922includes a bearing934(e.g., a needle bearing) for rotatably supporting a portion of the spindle926, and a blade guard945for enclosing the grinding tool960.

With continued reference toFIG.45, the tool-free attachment mechanism930) includes a clamping shaft980that extends through the hollow spindle926for co-rotation with the spindle926, a retaining ring978that is axially affixed to the clamping shaft980adjacent the upper portion927of the spindle926, a thrust plate977that is supported on the clamping shaft980by the retaining ring978, and a compression spring938that is disposed between the thrust plate977and the lower portion928of the spindle926configured to bias the thrust plate977and clamping shaft980upward (in the frame of reference ofFIG.45). The tool-free attachment mechanism930further includes a backing flange948that is coupled to the lower portion928of the spindle926. It is to be understood that the backing flange948is similar to the backing flange348of the grinder310such that the backing flange948includes the first mounting arrangement349(FIG.16) configured to interface with the grinding tool960during operation and installation. The first mounting arrangement349includes the axially extending protrusion351configured to pilot into the center aperture62(FIG.5) of the grinding tool960.

As illustrated, a post981extends in a generally downward direction from a lower end982of the clamping shaft980. A clamping assembly956is affixed, or otherwise attached, to a distal end983of the post981. Referring toFIGS.45-47, the clamping assembly956includes a first flange half957and a second flange half958that are coupled to the distal end983of the post981via central hinge959. The central hinge959is spring loaded and allows the flange halves957,958to rotate upward, as illustrated inFIG.46, from a position in which the flange halves957,958are aligned with each other along an alignment plane961(seeFIG.45) that is perpendicular to the clamping shaft980) and that passes through the center of the hinge959. It is to be understood that the flange halves957,958do not rotate downward past the alignment plane961. Further, the spring-loaded central hinge959biases the flange halves957,958into alignment along the alignment plane961.

The attachment mechanism930further includes a cam handle972that is pivotably supported on the gear case918via a rotatable joint connection969such that the handle972will not co-rotate with the clamping shaft980or the spindle926during operation of the grinder910. The cam handle972is configured to impart an axial force onto the stem portion976of the clamping shaft980to axially move the clamping shaft980within the spindle926.

With reference toFIGS.45-47, to install the grinding tool960, a user pivots the clamp handle972upward, which pushes both the clamping shaft980and the thrust plate977downward against the bias of the spring938, thereby pushing the clamping assembly956away from the backing flange948creating an axial space between the backing flange948and the clamping assembly956. Next, the user rotates the flange halves957,958upward relative to the central hinge959so that the clamping assembly956is folded to fit through the aperture62in the grinding tool960. The aperture62of the grinding tool960is fitted over the clamping assembly956. Then, the grinding tool960is moved upward until the clamp assembly956is fitted through the aperture62of the grinding tool960. Thereafter, the flange halves957,958are permitted to move back into alignment with each other and parallel to the grinding tool960. The user aligns the aperture62of the grinding tool960so that the axially extending protrusion951on the backing flange948pilots, or otherwise fits, into the aperture62. Finally, to axially and rotationally lock the grinding tool960with the spindle926, the user pivots the clamp handle972downward to the position depicted inFIG.45, which releases the clamping shaft980and allows the shaft980to move upward under the action of the rebounding compression spring938, moving the clamping assembly956into engagement with the grinding tool960to impart a clamping force onto the grinding tool960in order to close any axial space between the backing flange948and the clamping assembly956. To remove the grinding tool960, the user can perform the abovementioned steps in reverse.

FIGS.48and49illustrate an embodiment of another tool-free attachment mechanism1030that may be used with a grinder. The tool-free attachment mechanism1030includes a collar1032installed within a drive gear1034. A plurality of tool engagement jaws1036a,1036b,1036c,1036dare equally and radially disposed within the collar1032. Although four jaws1036are illustrated, it will be appreciated that two or more jaws1036may be used. Each of the jaws1036a,1036b,1036c,1036dincludes an outer surface1038that is generally parallel to a central axis1040of the tool-free attachment mechanism1030. The outer surface1038of each jaw1036a,1036b,1036c,1036dis formed with a spring pocket1042that extends annularly around the outer surface1038. A spring1044is disposed in each of the spring pockets1042and biases the jaws1036a,1036b,1036c,1036dradially inward.

As illustrated inFIG.48, each jaw1036a,1036b,1036c,1036dalso includes an inner surface1046that forms angle relative to the central axis1040. The tool-free attachment mechanism1030also includes a piston1048that is disposed along the central axis1040. The piston1048includes an upper end1050and a lower end1052. A frustoconical tip1054is affixed to, or extends from, the lower end1052of the piston1048. The frustoconical tip1054extends into a correspondingly shaped space1056formed within and surrounded by the inner surfaces1046of the jaws1036a,1036b,1036c,1036d. The outer surface engages the inner surfaces1046of the jaws1036a,1036b,1036c,1036d. A spring1060surrounds the piston1048and biases the piston1048and the frustoconical tip1054in a downward direction (i.e., into the space1056formed within the jaws1036a,1036b,1036c,1036d). As the frustoconical tip1054moves in a downward direction, the outer surface1058of the frustoconical tip1054engages the inner surfaces1046of the jaws1036a,1036b,1036c,1036dand pushes the jaws1036a,1036b,1036c,1036dradially outward.

The tool-free attachment mechanism1030also includes a release pin1062that is attached to the upper end1050of the piston1048. The release pin1062may be attached to a lever arm (e.g., a clamp handle of a grinder consistent with what is described herein). When the release pin1062is moved upward by the lever arm, the frustoconical tip1054of the piston1048moves upward and out of the space1056to disengage or substantially disengage from the jaws1036a,1036b,1036c,1036d. As the frustoconical tip1054moves out of the space1056, the spring1044biases the jaws1036a,1036b,1036c,1036dradially inward, which decreases the circumferential space taken up by the jaws1036a,1036b,1036c,1036d2. When the circumferential space taken up by the lower ends of the jaws1036a,1036b,1036c,1036dis less than an inner diameter of an aperture1064formed in the center of a grinding tool1066, the grinding tool1066may be released or removed from the tool-free attachment mechanism1030. As shown, the tool-free attachment mechanism1030also includes a spring1068that biases the jaws1036a,1036b,1036c,1036din a downward direction. A user installs the grinding tool1066on the tool-free attachment mechanism1030by moving the release pin1062in an upward direction. By moving the release pin1062in a downward direction, the frustoconical tip1054of the piston1048pushes the jaws1036a,1036b,1036c,1036din an outward direction to lock the grinding tool1066on the tool-free attachment mechanism1030.

FIG.50illustrates another power tool, such as a grinder1110. The grinder1110includes a housing1113including a motor housing1114portion in which an electric motor (not shown) having a motor shaft1115is located, and a gear case housing1118coupled to the housing1113. The housing1113also includes a handle portion (not shown) extending rearward from the motor housing portion1114, and a battery receptacle (not shown) for selectively receiving a battery pack for selectively electrically powering the motor. The grinder1110further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing1118substantially encloses and supports a portion of a drive assembly1120. The drive assembly1120includes the motor, a drive gear1121rotatably coupled to the motor shaft1115for receiving torque from the motor, a driven gear1119rotatably driven by the drive gear1121, and a spindle1126coupled for co-rotation with the driven gear1119. The grinder1110further includes a tool-free attachment mechanism1130for selectively mounting a grinding tool1160(e.g., a grinding disc) on a lower portion of the spindle1126.

The gear case housing1118includes an upper gear case1122and a lower gear case1123attached to the upper gear case1122and supports at least a portion of the drive assembly1120. The lower gear case1123includes a bearing1134for rotatably supporting a portion of the spindle1126, and a blade guard1145for enclosing the grinding tool1160.

With respect toFIGS.50-61, the tool-free attachment mechanism1130includes a spacer1142disposed on the spindle1126adjacent the bearing1134. The tool-free attachment mechanism1130also includes a backing flange1144disposed on the spindle1126and keyed to a first flat region1145(FIG.52) of the spindle1126to rotate with the spindle1126. A spring1146is provided between the spacer1142and the backing flange1144configured to bias the backing flange1144downward from the frame of reference ofFIG.50andFIG.51along the first flat region1145(FIG.52) of the spindle1126. It is to be understood that the spacer1142and the backing flange1144may not move radially relative to the spindle1126. The spacer1142and the backing flange1144rotate with the spindle1126. Further, the backing flange1144only moves axially along the spindle1126. The spring1146provides a force to create a clamping load in order to retain the grinding tool1160. The spring1146is held in place radially by inner walls1151,1152(FIG.53) formed on the spacer1142and an outer wall1153(FIGS.56and57) formed on the backing flange1144. It is to be understood that the backing flange1144is not removable from the spindle1126. Specifically, the backing flange1144is prevented from moving too far up the spindle1126by the lower gear case1122.

As shown inFIG.51-52, the tool-free attachment mechanism1130further includes a flange nut1154disposed on the spindle1126adjacent the end1156of the spindle1126. The flange nut1154is keyed to a second flat region1158on the spindle1126for co-rotation with the spindle1126. An intra flange1162is disposed on the spindle1126between the flange nut1154and the backing flange1144. The intra flange1162fits at least partly into a cavity1164(FIG.58) formed in the backing flange1144. The intra flange1162is slip fit onto the spindle1126and rotates thereon. The end1156of the spindle1126is formed with a groove1166and a spring clip1168fits into the groove1166to hold the flange nut1154and the intra flange1162on the spindle1126. The intra flange1162and the flange nut1154also prevent the back flange1144from slipping off of the spindle1126. The spindle11216also includes a shoulder1170adjacent the first flat region1145of the spindle1126to prevent the intra flange1162from moving up the spindle1126.

Both the flange nut1154and the intra flange1162have first and second mounting arrangements (FIGS.60and61: e.g., torque features), respectively, that interface with the grinding tool1160during operation and installation. The first mounting arrangement includes a plurality of axially extending protrusions1172on the flange nut1154and the second mounting arrangement includes a plurality of radially extending protrusions1174on the intra flange1162that are configured to misalign with and be received within similarly shaped recesses formed on the grinding tool1160. The flange nut1154supports the grinding tool1160during operation and the backing flange1144fits at least partially over the intra flange1162and provides clamping force. As illustrated inFIGS.59and60, the intra flange1162includes a ramp structure1176that cooperates with the backing flange1144to lift the backing flange1144away from the grinding tool1160to counteract the clamping force of the spring1146. The ramp structure1176also fits into, or nests, within a complementarily-shaped ramp groove1178(FIG.58) formed in an upper surface1180of the cavity1164of the backing flange1144. The ramp structure1176on the intra flange1162includes a ball1182(FIG.60) disposed within a cylindrical bore1183formed in the ramp structure1176. The ball1182is biased outward from the cylindrical bore1183by a spring (not shown). The ball1182within the ramp structure1176of the intra flange1162cooperates with a circular detent1184(FIG.58) formed in an upper surface1186of the ramp groove1178of the backing flange1144. The ball1182cooperates with the detent1184to prevent accidental actuation of the tool-free attachment mechanism1130.

FIG.52shows that the spindle1126include a first guide feature1190. The backing flange1192include a second guide feature1192(FIG.56). The flange nut1154includes a third guide feature1194(FIG.61). The guide features1190,1192,1194may be protrusions or slots and are provided to facilitate assembly of the tool-free attachment mechanism1130.

In order to install the grinding tool1160on the spindle1126, a central aperture of the grinding tool1160is aligned with the protrusions1172on the flange nut1154. Then, the grinding tool1160is slipped over the flange nut1154and onto the corresponding protrusions1174of the intra flange1162. In the installation position, the ramp structure1176holds the backing flange1144up and out of contact with the grinding tool1160and removes the clamping force of the spring1146from the grinding tool1160. Once the grinding tool1160is on the intra flange1162, the arbor lock on the grinder1110is engaged to lock the spindle1126. Then, the grinding tool1160and the intra flange1162are rotated approximately forty-five degrees (45°) counterclockwise until the ramp structure1176on the intra flange1162is aligned with the complementary shaped ramp groove1178formed in the backing flange1144. Once aligned, the ramp structure1176on the intra flange1162may nest within the ramp groove1178of the backing flange1144, as illustrated inFIG.31. With the ramp structure1176on the intra flange1162nested within the ramp groove1178of the backing flange1144, the spring1146biases the backing flange1144into contact with the grinding tool1160, as shown inFIG.33. As such, the backing flange1144can engage the grinding tool1160and provide a clamping force to hold the grinding tool1160in place against the flange nut1154.

To remove the grinding tool1160from the spindle1126, the arbor lock is engaged to lock the spindle1126. Then, the grinding tool1160and the intra flange1162are rotated approximately forty-five degrees (45°) clockwise until the ramp structure1176on the intra flange1162is misaligned with the ramp groove1178formed in the backing flange1144. As the ramp structure1176on the intra flange1162rotates out of the ramp groove1178, the ramp structure1176on the intra flange1162lifts the backing flange1144away from the grinding tool1160to remove the clamping force provided by the spring1146. Once the clamping force is removed, the aperture of the grinding tool1160may be re-aligned with the protrusions1172on the flange nut1154and the grinding tool1160may be removed from the spindle1126. It is to be understood that the flange nut1154may have substantially the same shape (top plan view) of the aperture of the grinding tool1160. On the other hand, the flange nut1154may be a shape (top plan view) that is slightly different from the aperture of the grinding tool1160to provide better clearance of the grinding tool1160over the flange nut1154during installation and removal of the grinding tool1160from the spindle1126of the grinder1110. In case the intra flange1162gets jammed on the backing flange1144, a spanner tool may be used to provide the necessary torque to rotate the intra flange1162on the spindle1126.

By having a grinder10,110,210,310,410,510,610,710,710a,810,910,1110that utilizes any of the tool-free attachment mechanisms30,130,230,330,430,530,630,730,730a,830,930,1030,1130the user can save both time and effort. Each of the mechanisms30,130,230,330,430,530,630,730,730a,830,930,1030,1130prevents the user from needing to use additional tools (e.g., a wrench) in order to remove and replace the grinding tool60,160,260,360,460,560,660,760,760a,860,960,1066,1160which reduces the overall labor required to change grinding tools, especially if the user needs to make multiple grinding tool changes in a short amount of time. Additionally, each of the mechanisms30,130,230,330,430,530,630,730,730a,830,930,1030,1130increases the user's working efficiency, as the mechanisms30,130,230,330,430,530,630,730,730a,830,930,1030,1130reduce the overall time between grinding tool changes, which preserves more time for the user to complete the task at hand.