CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to co-pending U.S. Provisional Patent

Application No. 63/307,753 filed on February 8, 2022, co-pending U.S. Provisional Patent Application No. 63/283,845 filed on November 29, 2021, and co-pending U.S. Provisional Patent Application No. 63/208,245 filed on June 8, 2021, the entire contents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] 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

[0003] 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

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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. [0008] 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.

[0009] 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.

[0010] Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is side cross-sectional view of a grinder in accordance with an embodiment of the invention.

[0012] FIG. 2 is a perspective view of a spindle for use with the grinder of FIG. 1.

[0013] FIG. 3 is a top view of a flange nut of a tool-free attachment mechanism for use with the grinder of FIG. 1.

[0014] FIG. 4 is a bottom view of a backing flange of the tool-free attachment mechanism for use with the grinder of FIG. 1.

[0015] FIG. 5 is a bottom view of a grinding tool for use with the grinder of FIG. 1.

[0016] FIG. 6A is bottom view of the grinding tool partially mounted to the spindle with the tool-free attachment mechanism.

[0017] FIG. 6B is a bottom view of the grinding tool fully mounted to the spindle with tool-free attachment mechanism.

[0018] FIG. 7 is side cross-sectional view of a grinder in accordance with another embodiment of the invention. [0019] FIG. 8 is a bottom view of a flange nut of a tool-free attachment mechanism for use with the grinder of FIG. 7.

[0020] FIG. 9 is a bottom view of a backing flange of the tool-free attachment mechanism for use with the grinder of FIG. 7.

[0021] FIG. 10A is a bottom view of the grinding tool partially mounted to the spindle with the tool-free attachment mechanism.

[0022] FIG. 10B is a bottom view of the grinding tool fully mounted to the spindle with tool-free attachment mechanism.

[0023] FIG. IOC is a side cross-sectional view of the grinding tool of FIG. 10B.

[0024] FIG. 11 is a side cross-sectional view of a grinder in accordance with another embodiment of the invention.

[0025] FIG. 12 is a bottom view of a flange nut of a tool-free attachment mechanism for use with the grinder of FIG. 11.

[0026] FIG. 13 is a bottom view of a backing flange of the tool-free attachment mechanism for use with the grinder of FIG. 11.

[0027] FIG. 14A is a bottom view of the grinding tool partially mounted to the spindle with the tool-free attachment mechanism.

[0028] FIG. 14B is a bottom view of the grinding tool fully mounted to the spindle with tool-free attachment mechanism.

[0029] FIG. 14C is a side cross-sectional view of the grinding tool of FIG. 14B.

[0030] FIG. 15 is side cross-sectional view of a grinder in accordance with another embodiment of the invention.

[0031] FIG. 16 is a perspective view of a backing flange of a tool-free attachment mechanism for use with the grinder of FIG. 15.

[0032] FIG. 17 is side cross-sectional view of a grinder in accordance with another embodiment of the invention. [0033] FIG. 18 is side cross-sectional view of a grinder in accordance with yet another embodiment of the invention.

[0034] FIG. 19 is a detailed cross-sectional view of the grinder of FIG. 18.

[0035] FIG. 20 is a perspective view of a spindle for use with the grinder of FIG. 18.

[0036] FIG. 21 is a top view of a backing flange of a tool-free attachment mechanism for use with the grinder of FIG. 18.

[0037] FIG. 22 is a top view of a spacer of the tool-free attachment mechanism for use with the grinder of FIG. 18.

[0038] FIG. 23 is a top view of a flange nut of a tool-free attachment mechanism for use with the grinder of FIG. 18.

[0039] FIG. 24 is a top view of an intra flange nut of a tool -free attachment mechanism for use with the grinder of FIG. 18.

[0040] FIG. 25 is a detailed cross-sectional view of the grinder of FIG. 18.

[0041] FIG. 26 is a perspective view of the intra flange nut of FIG. 24.

[0042] FIG. 27 is a bottom view of a grinding tool for use with the grinder of FIG. 18.

[0043] FIG. 28 is a partial bottom view of the grinder of FIG. 18.

[0044] FIG. 29 is a side cross-sectional view of the grinder of FIG. 18.

[0045] FIG. 30 is a top view of the grinder of FIG. 18.

[0046] FIG. 31 is a partial cross-sectional view of the intra flange nut of FIG. 24 engaged with the backing flange of FIG. 21.

[0047] FIG. 32 is a partial bottom view of the grinder of FIG. 18.

[0048] FIG. 33 is a side cross-sectional view of the grinder of FIG. 18.

[0049] FIG. 34 is a cross-sectional view of a grinder in accordance with still another embodiment of the invention. [0050] FIG. 35 is a cross-sectional view of a grinder in accordance with yet still another embodiment of the invention.

[0051] FIG. 36 is another cross-sectional view of the grinder of FIG. 35.

[0052] FIG. 37 is another cross-sectional view of the grinder of FIG. 35.

[0053] FIG. 38 is another cross-sectional view of the grinder of FIG. 35.

[0054] FIG. 39 is another cross-sectional view of the grinder of FIG. 35.

[0055] FIG. 40 is another cross-sectional view of the grinder of FIG. 35.

[0056] FIG. 41 is a bottom perspective view of the grinder of FIG. 35.

[0057] FIG. 42 is a bottom view of the grinder of FIG. 35.

[0058] FIG. 43 is a cross-sectional view of a grinder in accordance with another embodiment of the invention.

[0059] FIG. 44 is a side cross-sectional view of a grinder in accordance with still another embodiment of the invention.

[0060] FIG. 45 is a side cross-sectional view of a grinder in accordance with yet another embodiment of the invention.

[0061] FIG. 46 is another side cross-sectional view of the grinder of FIG. 46.

[0062] FIG. 47 is a bottom view of the grinder of FIG. 46.

[0063] FIG. 48 is a cross-sectional view of tool-free attachment mechanism for a grinder in accordance with another embodiment of the invention.

[0064] FIG. 49 is a bottom view of tool-free attachment mechanism for a grinder in accordance with another embodiment of the invention.

[0065] FIG. 50 is side cross-sectional view of a grinder in accordance with still another embodiment of the invention. [0066] FIG. 51 is a side view of a tool-free attachment mechanism for use with the grinder of FIG. 50.

[0067] FIG. 52 is a side view of a spindle for use with the grinder of FIG. 50.

[0068] FIG. 53 is a side view of a spacer of the tool-free attachment mechanism for use with the grinder of FIG. 50.

[0069] FIG. 54 is a top view of the spacer of FIG. 53.

[0070] FIG. 55 is a bottom view of the spacer of FIG. 53.

[0071] FIG. 56 is a side view of a backing flange of the tool-free attachment mechanism for use with the grinder of FIG. 50.

[0072] FIG. 57 is a top view of the backing flange of FIG. 56.

[0073] FIG. 58 is a bottom view of the backing flange of FIG. 56.

[0074] FIG. 59 is a side view of an intra flange nut of a tool-free attachment mechanism for use with the grinder of FIG. 50.

[0075] FIG. 60 is a top view of the intra flange nut of FIG. 59.

[0076] FIG. 61 is a top view of a flange nut of a tool-free attachment mechanism for use with the grinder of FIG. 50.

[0077] 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. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

[0078] FIG. 1 illustrates a power tool such as a grinder 10. The grinder 10 includes a housing 14 including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing 18 coupled to the housing 14. The housing 14 also includes a handle portion 15 extending 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 grinder 10 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing 18 substantially encloses and supports a portion of a drive assembly 20.

The drive assembly 20 includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear 19 rotatably driven by the drive gear, and a spindle 26 coupled for co-rotation with the driven gear 19. The grinder 10 further includes a tool-free attachment mechanism 30 for selectively mounting a grinding tool 60 (e.g., a grinding disc) on a lower portion of the spindle 26.

[0079] The gear case housing 18 includes an upper gear case (not shown) and a lower gear case 22 attached to the upper gear case and supports at least a portion of the drive assembly 20. The lower gear case 22 includes a bearing 34 for rotatably supporting a portion of the spindle 26, and a blade guard 45 for enclosing the grinding tool 60.

[0080] With respect to FIGS. 1-5B, the tool-free attachment mechanism 30 includes a spacer 42 rotatably coupled to the spindle 26, a spindle flange 44 supported on a plurality of shoulders 27 (FIG. 2) of the spindle 26, and a spring 38 provided between the spacer 42 and the flange 44 configured to bias the flange 44 downward from the frame of reference of FIG. 1. The tool-free attachment mechanism 30 further includes a backing flange 48 keyed to the spindle flange 44 for co-rotation with the backing flange 48, and a flange nut 56 threaded onto the spindle 26 until it abuts a retaining ring 52 positioned between the flange nut 56 and the backing flange 48. Both the backing flange 48 and the flange nut 56 have a first and second mounting arrangements 49, 57 (FIGS. 3-4; e.g., torque features), respectively, that interface with the grinding tool 60 during operation and installation. The first mounting arrangement 49 includes a plurality of axially extending protrusions and the second mounting arrangement 57 includes 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 arrangement 49.

[0081] FIG. 5 illustrates the grinding tool 60 for use with the grinder 10. The grinding tool 60 includes a center aperture 62 having a plurality of recesses 61 sized such that the recesses 61 align with first mounting arrangement 49 of the backing flange 48. [0082] With reference to FIGS. 1, 5, and 6A-B, to install the grinding tool 60, a user lifts the backing flange 48 upward along the spindle 26, which compresses the spring 38 and creates a space 64 between the backing flange 48 and the flange nut 56 for the user to install the grinding tool 60. Next, the user aligns the aperture 62 of the grinding tool 60 such that the recesses 61 of the tool 60 align with the second mounting arrangement 57 of the flange nut 56 and moves the grinding tool 60 over the flange nut 56 and into the space 64 (FIG. 6A). Once the grinding tool 60 is in the space 64, while continually lifting the backing flange 48, the user rotates (e.g., about 45 degrees) the grinding tool 60 relative to the backing flange 48 in order to misalign the first and second mounting arrangements 57, 49 of both the flange nut 56 and the backing flange 48, respectively, to rotationally lock the grinding tool 60 for co rotation with the spindle 26 (FIG. 6B). Lastly, to axially retain the grinding tool 60 on the spindle 26, the user releases the backing flange 48, permitting the spring 38 to rebound and push the backing flange 48 and the grinding tool 60 toward the flange nut 56 to axially secure the grinding tool 60 within the space 64. To remove the grinding tool 60, the user can perform the abovementioned steps in reverse.

[0083] FIG. 7 illustrates a grinder 110 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “100”. The grinder 110 includes a housing 114 including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing 118 coupled to the housing 114. The housing 114 also includes a handle portion 115 extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor. The grinder 110 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing 118 substantially encloses and supports a portion of a drive assembly 120. The drive assembly 120 includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear 119 rotatably driven by the drive gear, and a hollow spindle 126 coupled for co-rotation with the driven gear 119. The grinder 110 further includes a tool-free attachment mechanism 130 for selectively mounting a grinding tool 160 on a lower portion 128 of the spindle 126.

[0084] The gear case housing 118 further includes an upper gear case (not shown) and a lower gear case 122 attached to the upper gear case and supports at least a portion of the drive assembly 120. The lower gear case 122 includes a bearing 134 for rotatably supporting a portion of the spindle 126, a spacer 142 for supporting the lower portion 128 of the spindle 126, and a blade guard 145 for enclosing the grinding tool 160.

[0085] With respect to FIGS. 7-9, the tool-free attachment mechanism 130 includes a clamping shaft 180 extending through the hollow spindle 126 with a flange nut portion 156 integrated with the shaft 180 adjacent a lower end 128 of the spindle 126, and a stem portion 176 extending from the flange nut portion 156. The clamping shaft 180 is configured to be keyed to the spindle 126 with flats for co-rotation with the spindle 126. The mechanism 130 further includes a cam handle 172 pivotably supported on the stem portion 176 of the clamping shaft 180 via a rotatable j oint connection 169 such that the handle 172 will not co rotate with the clamping shaft 180 or the spindle 126 during operation of the grinder 110.

The cam handle 172 is configured to impart an axial force onto the stem portion 176 of the clamping shaft 180 to axially move the clamping shaft 180 within the spindle 126. The attachment mechanism 130 further includes a backing flange portion 148 integrated with the lower end 128 of the spindle 126, and a spring 138 positioned within the opening in the spindle 126 between the lower end 128 of the spindle 126 and the flange nut portion 156 for biasing the flange nut portion 156 in a downward direction from the frame of refence of FIG. 7.

[0086] With continued reference to FIGS. 7-9, both the backing flange portion 148

(FIG. 9) of the spindle 126 and the flange nut portion 156 of the clamping shaft 180 (FIG. 8) have first and second mounting arrangements 149, 157 (FIGS. 8-9; e.g., torque features), respectively, that interface with the grinding tool 160 during operation and installation. The first mounting arrangement 149 includes a plurality of axially extending protrusions and the second mounting arrangement 157 includes 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 arrangement 149. The grinding tool 60 (FIG. 5) is oriented so that the center aperture 62 and the plurality of recesses 61 align with second mounting arrangement 157 of the flange nut portion 156.

[0087] With reference to FIGS. 7 and 10A-10C, to install the grinding tool 160, a user pivots the clamp handle 172 upward (FIG. 7), which imparts a force onto the stem portion 176 of the clamping shaft 180 and moves the shaft 180 downward against the bias of the spring 138, thereby pushing the flange nut 156 portion of the shaft 180 away from the backing flange 148 portion of spindle 126 to create an axial space 164 for the user to install the grinding tool 160. Next, the user aligns the aperture 62 of the grinding tool 160 so the recesses 61 of the tool 160 align with the second mounting arrangement 157 of the flange nut 156 and moves the grinding tool 160 over the flange nut 156 and into the space 164 (FIG.

10 A). Once the grinding tool 160 is in the space 164, the user rotates (e.g., about 45 degrees) the grinding tool 160 about the backing flange 148 in order to misalign the first and second mounting arrangements 157, 149 of both the flange nut 156 and the backing flange 148, respectively, to rotationally lock the grinding tool 160 for co-rotation with the spindle 126 (FIG. 10B). Lastly, to axially retain the grinding tool 160 on the spindle 126, the user pivots the clamp handle 172 downward (FIG. IOC), which pulls the flange nut portion 156 of the clamping shaft 180 toward the spindle 126 against the bias of the spring 138, and axially secures the grinding tool 160 within the space 164. To remove the grinding tool 160, the user can perform the abovementioned steps in reverse.

[0088] FIG. 11 illustrates a grinder 210 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “200”. The grinder 210 includes a housing 214 including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing 218 coupled to the housing 214. The housing 214 also includes a handle portion 215 extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor. The grinder 210 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing 218 substantially encloses and supports a portion of a drive assembly 220. The drive assembly 220 includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear 219 rotatably driven by the drive gear, and a hollow spindle 226 coupled for co-rotation with the driven gear 219. The grinder 210 further includes a tool-free attachment mechanism 230 for selectively mounting a grinding tool 260 on a lower portion 228 of the spindle 226.

[0089] The gear case housing 218 further includes an upper gear case (not shown) and a lower gear case 222 attached to the upper gear case and supports at least a portion of the drive assembly 220. The lower gear case 222 includes a bearing 234 for rotatably supporting a portion of the spindle 226, a spacer 242 for supporting the lower portion 228 of the spindle 226, and a blade guard 245 for enclosing the grinding tool 260. [0090] With respect to FIGS. 11-14C, the tool-free attachment mechanism 230 includes a clamping shaft 280 extending through the hollow spindle 226 with a backing flange portion 248 integrated with the shaft 280 adjacent a lower end 228 of the spindle 226, and a stem portion 276 extending from the backing flange portion 248. The clamping shaft 280 is configured to be keyed to the spindle 226 with flats for co-rotation with the spindle 226. The attachment mechanism 230 further includes a cam handle 272 pivotably supported on the stem portion 276 of the clamping shaft 280 via a rotatable joint connection 269 such that the handle 272 will not co-rotate with the clamping shaft 280 or the spindle 226 during operation of the grinder 210. The cam handle 272 is configured to impart an axial force onto the stem portion 276 of the clamping shaft 280 to axially move the clamping shaft 280 within the spindle 226. The attachment mechanism 230 further includes a flange nut 256 threaded within the lower end 228 of the spindle 226 for co-rotation with the spindle 226, and a spring 238 positioned within the opening in the spindle 226 between the lower end 228 of the spindle 226 and the backing flange portion 248 for biasing the backing flange portion 248 in downward direction from the frame of reference of FIG. 11.

[0091] With reference to FIGS. 11-13, both the backing flange portion 248 (FIG. 12) of the clamping shaft 280 and the flange nut 256 (FIG. 13) have first and second mounting arrangements 257, 249 (FIGS. 12-13; e.g., torque features), respectively, that interface with the grinding tool 260 during operation and installation. The first mounting arrangement 249 includes a plurality of axially extending protrusions and the second mounting arrangement 257 includes a plurality of radially extending protrusions 262 and apertures 259 adjacent the protrusions 262. The protrusions of the first mounting arrangement 249 are configured to misalign with the protrusions 262 of the second mounting arrangement and extend into the apertures 259.

[0092] The grinding tool 60 (FIG. 5) is oriented so that the center aperture 62 and the plurality of recesses 61 align with plurality of protrusions 262 of the first mounting arrangement 257 of the flange nut 256.

[0093] With reference to FIGS. 11 and 14A-14C, to install the grinding tool 260, a user pivots the clamp handle 272 upward (FIG. 11), which pulls the clamping shaft 280 upward against the bias of the spring 238, thereby pulling the backing flange portion 248 of the shaft 280 upward to create an axial space 264 between the flange nut 256 for the user to install the grinding tool 260. Next, the user aligns the aperture 62 of the grinding tool 260 so the recesses 61 of the tool 260 align with the first mounting arrangement 257 of the flange nut 256 and moves the grinding tool 60 over the flange nut 256 and into the space 264 (FIG. 14A). Once the grinding tool 60 is in the space 264, the user rotates (e.g., about 45 degrees) the grinding tool 260 relative to the backing flange portion 248 in order misalign the first and second mounting arrangements 257, 249 of the flange nut 256 and backing flange portion 248, while simultaneously aligning the axial protrusions of the first mounting arrangement 249 of the backing flange 248 with the apertures 259 of the flange nut 256 such that the first mounting arrangement 249 is maintained in-line, but above the apertures 259 (FIG. 14B). Lastly, to lock the grinding tool axially and rotationally 260 with the spindle 226, the user pivots the clamp handle 272 downward (FIG. 14C), which releases the clamping shaft 280 and allows the shaft 280 to move downward under the bias of the rebounding spring 238, moving the first mounting arrangement 249 of the backing flange portion 248 into their respective apertures 259 of the flange nut 256 to secure the grinding tool 260 within the space 264. To remove the grinding tool 260, the user can perform the abovementioned steps in reverse.

[0094] FIG. 15 illustrates a grinder 310 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “300”. The grinder 310 includes a housing 314 including a motor housing portion in which an electric motor 315 having a motor shaft 316 is located, and a gear case 318 coupled to the housing 314. The housing 314 also includes ahandle portion extending rearward from the motor housing portion, and a battery receptacle for selectively receiving a battery for selectively electrically powering the motor 315. The grinder 310 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor 315. The gear case 318 substantially encloses and supports a portion of a drive assembly 320. The drive assembly 320 includes the motor 315, a drive gear 317 rotatably coupled to the motor shaft 316 for receiving torque from the motor 315, a driven gear 319 rotatably driven by the drive gear 317, and a hollow spindle 326 coupled for co rotation with the driven gear 319. The grinder 310 further includes a tool-free attachment mechanism 330 for selectively mounting a grinding tool 360 on a lower portion 328 of the spindle 326.

[0095] The gear case 318 further includes an upper gear case 321 and a lower gear case 322 attached to the upper gear case 321 and supports at least a portion of the drive assembly 320. The lower gear case 322 includes a bearing 334 (e.g., a needle bearing) for rotatably supporting a portion of the spindle 326, and a blade guard 345 for enclosing the grinding tool 360.

[0096] With continued reference to FIGS. 15 and 16, the tool-free attachment mechanism 330 includes a clamping shaft 380 extending through the hollow spindle 326 for co-rotation with the spindle 326, a plurality of clamping members 382 integrated with a lower portion of the shaft 380 adjacent the lower portion 328 of the spindle 326, a clamp pin 390 extending into the spindle 326 having a shaft portion 394 for being selectively retained by the clamping members 382, and a collar 396 affixed to the spindle 326 configured to engage and selectively bias the clamping members 382 inward toward one another for grasping the shaft portion 394 of the clamp pin 390. The attachment mechanism 330 further includes a thrust plate 377 axially affixed to the clamping shaft 380, a compression spring 338 located between the thrust plate 377 and the collar 396 for maintaining the collar 396 in engagement with the clamping members 382, and a backing flange 348 located on the lower portion 328 of the spindle 326 having a first mounting arrangement 349 (FIG. 16) that interfaces with the grinding tool 360 during operation and installation. The first mounting arrangement 349 includes an axially extending protrusion 351 configured to pilot into the center aperture 62 (FIG. 5) of the grinding tool 360.

[0097] The attachment mechanism 330 further includes a cam handle 372 pivotably supported on the gear case 318 via a rotatable joint connection 369 such that the handle 372 will not co-rotate with the clamping shaft 380 or the spindle 326 during operation of the grinder 310. The cam handle 372 is configured to impart an axial force onto a stem portion 376 of the clamping shaft 380 to axially move the clamping shaft 380 within the spindle 326.

[0098] With reference to FIGS. 15 and 16, to install the grinding tool 360, a user pivots the clamp handle 372 upward, which imparts a force onto the stem portion 376 of the clamping shaft 380 and moves the shaft 380 and the attached thrust plate 377 downward against the bias of the spring 338, thereby compressing the spring 338 against the collar 396. This opens a gap between the collar 396 and the clamping members 382 such that the members 382 slide down the collar 396 and move into the axial space 383 in the spindle 326. By moving into the axial space 383, the clamping members 382 are permitted to move outward and unclamp from the shaft portion 394 of the clamp pin 390. Next, with the shaft portion 394 undamped, the user can remove the clamp pin 390 from the spindle 326 so they can attach the grinding tool 360 to the grinder 310. Once the clamp pin 390 is removed, the user aligns the aperture 62 of the grinding tool 360 so that the axially extending protrusion 351 on the backing flange 348 pilots into the aperture 62. Once the grinding tool 360 is piloted onto the backing flange 348, the user re-inserts the clamp pin 390 so that the shaft portion 394 extends into the spindle 326 through both the aperture 62 of the grinding tool 360 and the backing flange 348. Lastly, to axially and rotationally retain the grinding tool 360 on the spindle 326, while continually holding the clamp pin 390 in the spindle 326, the user pivots the clamp handle 372 downward (into the position shown in FIG. 15), which moves the clamping shaft 380 and thrust plate 377 upward with the rebounding spring 338, thereby closing the gap between the collar 396 and the clamping members 382 and allowing the clamping members 382 to ride up the collar 396 as they are moving out of the space 383. As the clamping members 382 ride up the collar 396, the clamping members 382 are bent inward to engage and retain the shaft portion 394 of the clamp pin 390 within the spindle 326, which also applies a clamping force between the clamp pin 390 and the backing flange 348 to axially secure the grinding tool 360. To remove the grinding tool 360, the user can perform the abovementioned steps in reverse.

[0099] FIG. 17 illustrates a grinder 410 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “400”. The grinder 410 includes a housing 414 including a motor housing portion in which an electric motor 415 having a motor shaft 416 is located, and a gear case 418 coupled to the housing 414. The housing 414 also 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 motor 415. The grinder 410 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor 415. The gear case 418 substantially encloses and supports a portion of a drive assembly 420. The drive assembly 420 includes the motor 415, a drive gear 417 rotatably coupled to the motor shaft 416 for receiving torque from the motor 415, a driven gear 419 rotatably driven by the drive gear 417, and a hollow spindle 426 coupled for co rotation with the driven gear 419. The grinder 410 further includes a tool-free attachment mechanism 430 for selectively mounting a grinding tool 460 on a lower portion 428 of the spindle 426. [00100] The gear case 418 further includes an upper gear case 421 and a lower gear case 422 attached to the upper gear case 421 and supports at least a portion of the drive assembly 420. The upper gear case 421 includes a spindle lock 488 for being selectively received within an aperture 487 on an upper portion 427 of the spindle 426 for rotatably locking the spindle 426 when the user is changing the grinding tool 460. The lower gear case 422 includes a bearing 434 (e.g., a needle bearing) for rotatably supporting a portion of the spindle 426, and a blade guard 445 for enclosing the grinding tool 460.

[00101] With continued reference to FIG. 17, the tool-free attachment mechanism 430 includes a clamping shaft 480 extending through the hollow spindle 426 for co-rotation with the spindle 426, a retaining ring 478 axially affixed to the clamping shaft 480 adjacent the upper portion 427 of the spindle 426, a thrust plate 477 supported on the clamping shaft 480 by the retaining ring 478, and a compression spring 438 provided between the thrust plate 477 and the lower portion 428 of the spindle 426 configured to bias the thrust plate 477 and clamping shaft 480 upward from the frame of reference of FIG. 17. The tool-free attachment mechanism 430 further includes a backing flange 448 coupled to the lower portion 428 of the spindle 426, and a flange nut 456 threaded onto a threaded portion 485 of the spindle 426 until it abuts the grinding tool 460. The backing flange 448 is similar to the backing flange 348 of the grinder 310 such that the backing flange 448 includes the first mounting arrangement 349 (FIG. 16) configured to interface with the grinding tool 460 during operation and installation. The first mounting arrangement 349 includes the axially extending protrusion 351 configured to pilot into the center aperture 62 (FIG. 5) of the grinding tool 460.

[00102] The attachment mechanism 430 further includes a cam handle 472 pivotably supported on the gear case 418 via a rotatable joint connection 469, such that the handle 472 will not co-rotate with the clamping shaft 480 or the spindle 426 during operation of the grinder 410. The cam handle 472 is configured to impart an axial force onto the stem portion

476 of the clamping shaft 480 to axially move the clamping shaft 480 within the spindle 426.

[00103] With further reference to FIG. 17, to install the grinding tool 460, a user pivots the clamp handle 472 upward, which pushes both the clamping shaft 480 and the thrust plate

477 downward against the bias of the spring 438, thereby pushing the flange nut 456 away from the backing flange 448 creating an axial space between the backing flange 448 and the flange nut 456 in which the grinding tool 460 is installed and held. Next, the user actuates the spindle lock 488, which moves the lock 488 into the aperture 487 in order to rotationally lock the spindle 426 and unthreads the flange nut 456 from the threaded portion 485 of the clamping shaft 480. Once the flange nut 456 is removed, the user aligns the aperture 62 of the grinding tool 460 so that the axially extending protrusion 451 on the backing flange 448 pilots into the aperture 62. In this position, the grinding tool 460 is loosely retained on the clamping shaft 480 allowing the user to simultaneously depress the spindle lock 488 and thread the flange nut 456 back onto the clamping shaft 480 until it abuts the grinding tool 460. Lastly, to axially and rotationally lock the grinding tool 460 with the spindle 426, the user pivots the clamp handle 472 downward (shown in FIG. 17), which releases the clamping shaft 480 and allows the shaft 480 to move upward under the action of the rebounding compression spring 438, moving the flange nut 456 into engagement with the grinding tool 460 to impart a clamping force onto the grinding tool 460 in order to close any axial space between the backing flange 448 and the flange nut 456. To remove the grinding tool 460, the user can perform the abovementioned steps in reverse.

[00104] FIG. 18 illustrates another power tool, such as a grinder 510. The grinder 510 includes a housing 514 including a motor housing portion in which an electric motor (not shown) having a motor shaft is located, and a gear case housing 518 coupled to the housing 514. The housing 514 also includes a handle portion 515 extending 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 grinder 510 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing 518 substantially encloses and supports a portion of a drive assembly 520. The drive assembly 520 includes the motor, a drive gear (not shown) rotatably coupled to the motor shaft for receiving torque from the motor, a driven gear 519 rotatably driven by the drive gear, and a spindle 526 coupled for co-rotation with the driven gear 519. The grinder 510 further includes a tool-free attachment mechanism 530 for selectively mounting a grinding tool 560 (e.g., a grinding disc) on a lower portion of the spindle 526.

[00105] The gear case housing 518 includes an upper gear case (not shown) and a lower gear case 522 attached to the upper gear case and supports at least a portion of the drive assembly 520. The lower gear case 522 includes a bearing 534 for rotatably supporting a portion of the spindle 526, and a blade guard 545 for enclosing the grinding tool 560. [00106] With respect to FIGS. 18-23, the tool-free attachment mechanism 530 includes a spacer 542 keyed to a flat region 543 (FIG. 20) and therefore, rotatably coupled to the spindle 526, a backing flange 544 keyed to the flat region 543 (FIG. 20) of the spindle 526 and supported on a shoulder 527 (FIG. 20) of the spindle 526, and a spring 538 provided between the spacer 542 and the backing flange 544 configured to bias the backing flange 544 downward from the frame of reference of FIG. 18 and FIG. 19 along the flat region 543 (FIG 20) of the spindle 526. It is to be understood that the spacer 542 and the backing flange 544 may not move radially relative to the spindle 526. The spacer 542 and the backing flange 544 rotate with the spindle 526. Further, the backing flange 544 only moves axially along the spindle 526. The spring 538 provides a force to create a clamping load in order to retain the grinding tool 560. The spring 538 is held in place by groove features 551, 553 formed in the spacer 542 and the backing flange 544. It is to be understood that the backing flange 544 is not removable from the spindle 526. Specifically, the backing flange 544 is prevented from moving too far down the spindle 526 by the shoulder 527. Further, the backing flange 544 is prevented from moving too far up the spindle 526 by the lower gear case 522.

[00107] As shown in FIG. 23-25, the tool-free attachment mechanism 530 further includes a flange nut 548 pressed onto the spindle 526 for co-rotation with the spindle 526.

An intra flange 550 is disposed on the spindle 526 adjacent to the flange nut 548. The intra flange 550 is slip fit onto the spindle 526 and rotates thereon. Both the flange nut 548 and the intra flange 550 have a first and second mounting arrangements 549, 557 (FIGS. 23-24; e.g., torque features), respectively, that interface with the grinding tool 560 during operation and installation. The first mounting arrangement 549 includes a plurality of axially extending protrusions and the second mounting arrangement 557 includes a plurality of radially extending protrusions that are configured to misalign with and be received similarly shaped recesses formed on the grinding tool 560. The flange nut 548 supports the grinding tool 560 during operation and the backing flange 544 fit at least partially over the intra flange 550 and provides clamping force. As illustrated in FIG. 26, the intra flange 550 includes a ramp structure 555 that may cooperate with the backing flange 544 to lift the backing flange 544 away from the grinding tool 560, as shown in FIG. 29, and counteract the clamping force of the spring 538. [00108] FIG. 27 illustrates the grinding tool 560 for use with the grinder 510. The grinding tool 560 includes a center aperture 562 having a plurality of recesses 561 sized such that the recesses 561 align with first mounting arrangement 549 of the flange nut 548.

[00109] In order to install the grinding tool 560 on the spindle 526, the aperture 562 of the grinding tool 560 is aligned with the protrusions on the flange nut 548, as shown in FIG. 28. Then, the grinding tool 560 is slipped over the flange nut 548 and onto the corresponding protrusions of the intra flange 550. In the installation position, as depicted in FIG. 29, the ramp structure 555 holds the backing flange 544 up and out of contact with the grinding tool 560 and removes the clamping force of the spring 538 from the grinding tool 560. Once the grinding tool 560 is on the intra flange 550, the arbor lock on the grinder 510 is engaged to lock the spindle 526. Then, the grinding tool 560 and the intra flange 550 are rotated approximately forty-five degrees (45°) counterclockwise until the ramp structure 555 on the intra flange 550 is aligned with a complementary shaped ramp groove 565 formed in the backing flange 544. Once aligned, the ramp structure 555 on the intra flange 550 may nest within the ramp groove 565 of the backing flange 544, as illustrated in FIG. 31. With the ramp structure 555 on the intra flange 550 nested within the ramp groove 565 of the backing flange 544, the spring 538 biases the backing flange 544 into contact with the grinding tool 560, as shown in FIG. 33. As such, the backing flange 544 can engage the grinding tool 560 and provide a clamping force to hold the grinding tool 560 in place against the flange nut 548.

[00110] To remove the grinding tool 560 from the spindle 526, the arbor lock is engaged to lock the spindle 526. Then, the grinding tool 560 and the intra flange 550 are rotated approximately forty-five degrees (45°) clockwise until the ramp structure 555 on the intra flange 550 is misaligned with the ramp groove 565 formed in the backing flange 544.

As the ramp structure 555 on the intra flange 550 rotates out of the ramp groove 565, the ramp structure 555 on the intra flange 550 lifts the backing flange 544 away from the grinding tool 560 to remove the clamping force provided by the spring 538, as illustrated in FIG. 29. Once the clamping force is removed, the aperture 562 of the grinding tool 560 may be re-aligned with the protrusions on the flange nut 548 and the grinding tool 560 may be removed from the spindle 526.

[00111] FIG. 34 illustrates a grinder 610 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “600”. The grinder 610 includes a housing 614 including a motor housing portion in which an electric motor 615 having a motor shaft 616 is located, and a gear case 618 coupled to the housing 614. The housing 614 also 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 motor 615. The grinder 610 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor 615. The gear case 618 substantially encloses and supports a portion of a drive assembly 620. The drive assembly 620 includes the motor 615, a drive gear 617 rotatably coupled to the motor shaft 616 for receiving torque from the motor 615, a driven gear 619 rotatably driven by the drive gear 617, and a hollow spindle 626 coupled for co rotation with the driven gear 619. The grinder 610 further includes a tool-free attachment mechanism 630 for selectively mounting a grinding tool 660 on a lower portion 628 of the spindle 626.

[00112] The gear case 618 further includes an upper gear case 621 and a lower gear case 622 attached to the upper gear case 621 and supports at least a portion of the drive assembly 620. The upper gear case 621 includes a spindle lock 688 for being selectively received within an aperture 687 on an upper portion 627 of the spindle 626 for rotatably locking the spindle 626 when the user is changing the grinding tool 660. The lower gear case 622 includes a bearing 634 (e.g., a needle bearing) for rotatably supporting a portion of the spindle 626, and a blade guard 645 for enclosing the grinding tool 660.

[00113] With continued reference to FIG. 34, the tool-free attachment mechanism 630 includes a clamping shaft 680 extending through the hollow spindle 626 for co-rotation with the spindle 626, a retaining ring 678 axially affixed to the clamping shaft 680 adjacent the upper portion 627 of the spindle 626, a thrust plate 677 supported on the clamping shaft 680 by the retaining ring 678, and a compression spring 638 provided between the thrust plate 677 and the lower portion 628 of the spindle 626 configured to bias the thrust plate 677 and clamping shaft 680 upward from the frame of reference of FIG. 34. The tool-free attachment mechanism 630 further includes a backing flange 648 coupled to the lower portion 628 of the spindle 626, and a flange bolt 656 having a head 657 and a threaded stem 658 that extends from the head 657. The threaded stem 658 of the flange bolt 656 is threaded into a threaded bore 685 formed in the clamping shaft 680 until the head 657 of the flange bolt 656 abuts the grinding tool 660. The backing flange 648 is similar to the backing flange 348 of the grinder 310 such that the backing flange 648 includes the first mounting arrangement 349 (FIG. 16) configured to interface with the grinding tool 660 during operation and installation. The first mounting arrangement 349 includes the axially extending protrusion 651 configured to pilot into the center aperture 62 (FIG. 5) of the grinding tool 660.

[00114] The attachment mechanism 630 further includes a cam handle 672 pivotably supported on the gear case 618 via a rotatable joint connection 669 such that the handle 672 will not co-rotate with the clamping shaft 680 or the spindle 626 during operation of the grinder 610. The cam handle 672 is configured to impart an axial force onto the stem portion

676 of the clamping shaft 680 to axially move the clamping shaft 680 within the spindle 626.

[00115] With further reference to FIG. 34, to install the grinding tool 660, a user pivots the clamp handle 672 upward, which pushes both the clamping shaft 680 and the thrust plate

677 downward against the bias of the spring 638, thereby pushing the flange bolt 656 away from the backing flange 648 creating an axial space between the backing flange 648 and the head 657 of the flange bolt 656 in which the grinding tool 660 is installed and held. Next, the user actuates the spindle lock 688, which moves the lock 688 into the aperture 687 to rotationally lock the spindle 626, and unthreads the flange bolt 656 from the threaded bore 685 of the clamping shaft 680. Once the flange bolt 656 is removed, the user aligns the aperture 62 of the grinding tool 660 so that the axially extending protrusion 651 on the backing flange 648 pilots into the aperture 62. In this position, the grinding tool 660 is loosely retained on the clamping shaft 680 allowing the user to simultaneously depress the spindle lock 688 and thread the flange bolt 656 back into the threaded bore 685 of the clamping shaft 680 until the head 657 of the flange bolt 656 abuts the grinding tool 660. Lastly, to axially and rotationally lock the grinding tool 660 with the spindle 626, the user pivots the clamp handle 672 downward (shown in FIG. 34), which releases the clamping shaft 680 and allows the shaft 680 to move upward under the action of the rebounding compression spring 638, moving the head 657 of the flange bolt 656 into engagement with the grinding tool 660 to impart a clamping force onto the grinding tool 660 in order to close any axial space between the backing flange 648 and the head 657 of the flange bolt 656. To remove the grinding tool 660, the user can perform the abovementioned steps in reverse.

[00116] FIG. 35 illustrates a grinder 710 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “700”. The grinder 710 includes a housing 714 including a motor housing portion in which an electric motor 715 having a motor shaft 716 is located, and a gear case 718 coupled to the housing 714. The housing 714 also 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 motor 715. The grinder 710 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor 715. The gear case 718 substantially encloses and supports a portion of a drive assembly 720. The drive assembly 720 includes the motor 715, a drive gear 717 rotatably coupled to the motor shaft 716 for receiving torque from the motor 715, a driven gear 719 rotatably driven by the drive gear 717, and a hollow spindle 726 coupled for co rotation with the driven gear 719. The grinder 710 further includes a tool-free attachment mechanism 730 for selectively mounting a grinding tool 760 on a lower portion 728 of the spindle 726.

[00117] The gear case 718 further includes an upper gear case 721 and a lower gear case 722 attached to the upper gear case 721 and supports at least a portion of the drive assembly 720. The upper gear case 721 includes a spindle lock 788 for being selectively received within an aperture 787 on an upper portion 727 of the spindle 726 for rotatably locking the spindle 726 when the user is changing the grinding tool 760. The lower gear case 722 includes a bearing 734 (e.g., a needle bearing) for rotatably supporting a portion of the spindle 726, and a blade guard 745 for enclosing the grinding tool 760.

[00118] With continued reference to FIG. 35, the tool-free attachment mechanism 730 includes a clamping shaft 780 extending through the hollow spindle 726 for co-rotation with the spindle 726, a retaining ring 778 axially affixed to the clamping shaft 780 adjacent the upper portion 727 of the spindle 726, a thrust plate 777 supported on the clamping shaft 780 by the retaining ring 778, and a compression spring 738 provided between the thrust plate 777 and the lower portion 728 of the spindle 726 configured to bias the thrust plate 777 and clamping shaft 780 upward from the frame of reference of FIG. 35. The clamping shaft 780 further includes a straight post 781 extending in a generally downward direction from the clamping shaft 780 as illustrated in FIG. 35. A ball 782 is formed on a distal end of the straight post 781.

[00119] The tool-free attachment mechanism 730 further includes a backing flange 748 that is coupled to the lower portion 728 of the spindle 726, and a clamping flange 756 that is rotatably disposed on the ball 782 of the clamping shaft 780 (e.g., the clamping flange 756 and the ball 782 define a ball-and-socket joint). The clamping flange 756 includes a central hub 757 that is sized and shaped to fit over and at least partially around the ball 782 to allow the clamping flange 756 to rotate on the ball 782 but not disengage or disassemble from the ball 782. The clamping flange 756 also includes a tool engagement portion 758 that extends radially outward from the central hub 757 of the clamping flange 756. When a grinding tool 760 is installed on the grinder 710, as described below, the grinding tool 760 may be held in place between the tool engagement portion 758 of the clamping flange 756 and the backing flange 748. It is to be understood that the backing flange 748 is similar to the backing flange 348 of the grinder 310 such that the backing flange 748 includes the first mounting arrangement 349 (FIG. 16) configured to interface with the grinding tool 760 during operation and installation. The first mounting arrangement 349 includes the axially extending protrusion 351 configured to pilot into the center aperture 62 (FIG. 5) of the grinding tool 760.

[00120] FIG. 43 illustrates another example of a tool-free attachment mechanism 730a that is similar to the attachment mechanism 730. More specifically, the attachment mechanism 730a includes a clamping shaft 780a with a curved post 781a that extends in a generally downward direction from the clamping shaft 780a. A ball 782a is formed on a distal end of the curved post 781a. A clamping flange 756a fits over the ball 782a in a manner consistent with what is described relative to FIG. 35. The curved post 781a allows the clamping flange 756a to tilt on the ball 782a to a greater degree than it would on the straight post 781. This configuration provides additional clearance when installing and removing a griding tool 760a from the grinder 710a, as described in detail below.

[00121] Returning to FIG. 35, the attachment mechanism 730 further includes a cam handle 772 that is pivotably supported on the gear case 718 via a rotatable joint connection 769 such that the handle 772 will not co-rotate with the clamping shaft 780 or the spindle 726 during operation of the grinder 710. The cam handle 772 is configured to impart an axial force onto the stem portion 776 of the clamping shaft 780 to axially move the clamping shaft 780 within the spindle 726.

[00122] To install the grinding tool 760, a user pivots the clamp handle 772 upward, which pushes both the clamping shaft 780 and the thrust plate 777 downward against the bias of the spring 738, thereby pushing the clamping flange 756 away from the backing flange 748 creating an axial space between the backing flange 748 and the clamping flange 756 as illustrated in FIG. 36. Next, as shown in FIG. 36, the user rotates the clamping flange 756 on the ball 782 so that the clamping flange 756 is tilted, or angled, with respect to the backing flange 748. The aperture 62 of the grinding tool 760 is fitted over a first end of the clamping flange 756. Then, as depicted in FIG. 37, the grinding tool 760 is moved toward the straight post 781 that supports the ball 782 until the aperture 62 of the grinding tool 760 substantially clears the clamping flange 756, as shown in FIG. 38. Thereafter, the clamping flange 756 is rotated to a position in which the tool engagement portion 758 is generally parallel to the grinding tool 760, as shown in FIG. 39. With reference to FIGS. 35, 38, and 39, the user aligns the aperture 62 of the grinding tool 760 so that the axially extending protrusion 751 on the backing flange 748 pilots, or otherwise fits, into the aperture 62. With reference to FIGS. 35 and 40-42, the user pivots the clamp handle 772 downward (shown in FIG. 35) to axially and rotationally lock the grinding tool 760 on the spindle 726. That is, this movement releases the clamping shaft 780 and allows the shaft 780 to move upward due to the bias of the compression spring 738, which moves the clamping flange 756 into engagement with the grinding tool 760 to impart a clamping force onto the grinding tool 760. To remove the grinding tool 760, the user can perform the abovementioned steps in reverse.

[00123] FIG. 44 illustrates a grinder 810 in accordance with another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “800”. The grinder 810 includes a housing 814 including a motor housing portion in which an electric motor 815 having a motor shaft 816 is located, and a gear case 818 coupled to the housing 814. The housing 814 also 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 motor 815. The grinder 810 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor 815. The gear case 818 substantially encloses and supports a portion of a drive assembly 820. The drive assembly 820 includes the motor 815, a drive gear 817 rotatably coupled to the motor shaft 816 for receiving torque from the motor 815, a driven gear 819 rotatably driven by the drive gear 817, and a hollow spindle 826 coupled for co rotation with the driven gear 819. The grinder 810 further includes a tool-free attachment mechanism 830 for selectively mounting a grinding tool 860 on a lower portion 828 of the spindle 826. [00124] The gear case 818 further includes an upper gear case 821 and a lower gear case 822 that is attached to the upper gear case 821 and supports at least a portion of the drive assembly 820. The upper gear case 821 includes a spindle lock 888 for being selectively received within an aperture 887 on an upper portion 827 of the spindle 826 for rotatably locking the spindle 826 when the user is changing the grinding tool 860. The lower gear case 822 includes a bearing 834 (e.g., a needle bearing) for rotatably supporting a portion of the spindle 826, and a blade guard 845 for enclosing the grinding tool 860.

[00125] With continued reference to FIG. 44, the tool-free attachment mechanism 830 includes a clamping shaft 880 extending through the hollow spindle 826 for co-rotation with the spindle 826, a retaining ring 878 axially affixed to the clamping shaft 880 adjacent the upper portion 827 of the spindle 826, a thrust plate 877 supported on the clamping shaft 880 by the retaining ring 878, and a compression spring 838 provided between the thrust plate 877 and the lower portion 828 of the spindle 826 configured to bias the thrust plate 877 and clamping shaft 880 upward from the frame of reference of FIG. 44. The tool-free attachment mechanism 830 further includes a backing flange 848 that is coupled to the lower portion 828 of the spindle 826. A flexible cable 881 extends in a generally downward direction, as illustrated in FIG. 44, from a lower end 882 of the clamping shaft 880. A clamping flange 856 is affixed, or otherwise attached, to a distal end 883 of the flexible cable 881. It is to be understood that the backing flange 848 is similar to the backing flange 348 of the grinder 310 such that the backing flange 848 includes the first mounting arrangement 349 (FIG. 16) configured to interface with the grinding tool 860 during operation and installation. The first mounting arrangement 349 includes the axially extending protrusion 351 configured to pilot into the center aperture 62 (FIG. 5) of the grinding tool 860.

[00126] The attachment mechanism 830 further includes a cam handle 872 that is pivotably supported on the gear case 818 via a rotatable joint connection 869 such that the handle 872 will not co-rotate with the clamping shaft 880 or the spindle 826 during operation of the grinder 810. The cam handle 872 is configured to impart an axial force onto the stem portion 876 of the clamping shaft 880 to axially move the clamping shaft 880 within the spindle 826.

[00127] With further reference to FIG. 44, to install the grinding tool 860, a user pivots the clamp handle 872 upward, which pushes both the clamping shaft 880 and the thrust plate 877 downward against the bias of the spring 838, thereby pushing the clamping flange 856 away from the backing flange 848 creating an axial space between the backing flange 848 and the clamping flange 856 as shown. Next, the user rotates the clamping flange 856 via the flexible cable 881 so that the clamping flange 856 is tilted, or angled, with respect to the backing flange 848. The grinding tool 860 is fitted over the clamping flange 856 via the aperture 62. Then, the grinding tool 860 is moved upward along the flexible cable 881 until the clamp flange 856 is fitted through the aperture 62. Thereafter, the clamping flange 856 is rotated back into a position in which the clamping flange 856 is parallel to the grinding tool 860 and the user aligns the aperture 62 of the grinding tool 860 so that the axially extending protrusion 851 on the backing flange 848 pilots, or otherwise fits, into the aperture 62.

Finally, to axially and rotationally lock the grinding tool 860 with the spindle 826, the user pivots the clamp handle 872 downward to the position depicted in FIG. 44, which releases the clamping shaft 880 and allows the shaft 880 and flexible cable 881 to move upward under the action of the rebounding compression spring 838, moving the clamping flange 856 into engagement with the grinding tool 860 to impart a clamping force onto the grinding tool 860 in order to close any axial space between the backing flange 848 and the clamping flange 856. To remove the grinding tool 860, the user can perform the abovementioned steps in reverse.

[00128] FIG. 45 illustrates a grinder 910 in accordance with yet another embodiment of the invention. Like components and features of the grinder 10 of FIGS. 1-6B will be used plus “900”. The grinder 910 includes a housing 914 including a motor housing portion in which an electric motor 915 having a motor shaft 916 is located, and a gear case 918 coupled to the housing 914. The housing 914 also 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 motor 915. The grinder 910 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor 915. The gear case 918 substantially encloses and supports a portion of a drive assembly 920. The drive assembly 920 includes the motor 915, a drive gear 917 rotatably coupled to the motor shaft 916 for receiving torque from the motor 915, a driven gear 919 rotatably driven by the drive gear 917, and a hollow spindle 926 coupled for co rotation with the driven gear 919. The grinder 910 further includes a tool-free attachment mechanism 930 for selectively mounting a grinding tool 960 on a lower portion 928 of the spindle 926. [00129] The gear case 918 further includes an upper gear case 921 and a lower gear case 922 attached to the upper gear case 921 and supports at least a portion of the drive assembly 920. The upper gear case 921 includes a spindle lock 988 for being selectively received within an aperture 987 on an upper portion 927 of the spindle 926 for rotatably locking the spindle 926 when the user is changing the grinding tool 960. The lower gear case 922 includes a bearing 934 (e.g., a needle bearing) for rotatably supporting a portion of the spindle 926, and a blade guard 945 for enclosing the grinding tool 960.

[00130] With continued reference to FIG. 45, the tool-free attachment mechanism 930 includes a clamping shaft 980 that extends through the hollow spindle 926 for co-rotation with the spindle 926, a retaining ring 978 that is axially affixed to the clamping shaft 980 adjacent the upper portion 927 of the spindle 926, a thrust plate 977 that is supported on the clamping shaft 980 by the retaining ring 978, and a compression spring 938 that is disposed between the thrust plate 977 and the lower portion 928 of the spindle 926 configured to bias the thrust plate 977 and clamping shaft 980 upward (in the frame of reference of FIG. 45).

The tool-free attachment mechanism 930 further includes a backing flange 948 that is coupled to the lower portion 928 of the spindle 926. It is to be understood that the backing flange 948 is similar to the backing flange 348 of the grinder 310 such that the backing flange 948 includes the first mounting arrangement 349 (FIG. 16) configured to interface with the grinding tool 960 during operation and installation. The first mounting arrangement 349 includes the axially extending protrusion 351 configured to pilot into the center aperture 62 (FIG. 5) of the grinding tool 960.

[00131] As illustrated, a post 981 extends in a generally downward direction from a lower end 982 of the clamping shaft 980. A clamping assembly 956 is affixed, or otherwise attached, to a distal end 983 of the post 981. Referring to FIGS. 45-47, the clamping assembly 956 includes a first flange half 957 and a second flange half 958 that are coupled to the distal end 983 of the post 981 via central hinge 959. The central hinge 959 is spring loaded and allows the flange halves 957, 958 to rotate upward, as illustrated in FIG. 46, from a position in which the flange halves 957, 958 are aligned with each other along an alignment plane 961 (see FIG. 45) that is perpendicular to the clamping shaft 980 and that passes through the center of the hinge 959. It is to be understood that the flange halves 957, 958 do not rotate downward past the alignment plane 961. Further, the spring-loaded central hinge 959 biases the flange halves 957, 958 into alignment along the alignment plane 961. [00132] The atachment mechanism 930 further includes a cam handle 972 that is pivotably supported on the gear case 918 via a rotatable joint connection 969 such that the handle 972 will not co-rotate with the clamping shaft 980 or the spindle 926 during operation of the grinder 910. The cam handle 972 is configured to impart an axial force onto the stem portion 976 of the clamping shaft 980 to axially move the clamping shaft 980 within the spindle 926.

[00133] With reference to FIGS. 45-47, to install the grinding tool 960, a user pivots the clamp handle 972 upward, which pushes both the clamping shaft 980 and the thrust plate 977 downward against the bias of the spring 938, thereby pushing the clamping assembly 956 away from the backing flange 948 creating an axial space between the backing flange 948 and the clamping assembly 956. Next, the user rotates the flange halves 957, 958 upward relative to the central hinge 959 so that the clamping assembly 956 is folded to fit through the aperture 62 in the grinding tool 960. The aperture 62 of the grinding tool 960 is fited over the clamping assembly 956. Then, the grinding tool 960 is moved upward until the clamp assembly 956 is fited through the aperture 62 of the grinding tool 960. Thereafter, the flange halves 957, 958 are permited to move back into alignment with each other and parallel to the grinding tool 960. The user aligns the aperture 62 of the grinding tool 960 so that the axially extending protrusion 951 on the backing flange 948 pilots, or otherwise fits, into the aperture 62. Finally, to axially and rotationally lock the grinding tool 960 with the spindle 926, the user pivots the clamp handle 972 downward to the position depicted in FIG. 45, which releases the clamping shaft 980 and allows the shaft 980 to move upward under the action of the rebounding compression spring 938, moving the clamping assembly 956 into engagement with the grinding tool 960 to impart a clamping force onto the grinding tool 960 in order to close any axial space between the backing flange 948 and the clamping assembly 956. To remove the grinding tool 960, the user can perform the abovementioned steps in reverse.

[00134] FIGS. 48 and 49 illustrate an embodiment of another tool-free attachment mechanism 1030 that may be used with a grinder. The tool-free atachment mechanism 1030 includes a collar 1032 installed within a drive gear 1034. A plurality of tool engagement jaws 1036a, 1036b, 1036c, 1036d are equally and radially disposed within the collar 1032. Although four jaws 1036 are illustrated, it will be appreciated that two or more jaws 1036 may be used. Each of the jaws 1036a, 1036b, 1036c, 1036d includes an outer surface 1038 that is generally parallel to a central axis 1040 of the tool-free atachment mechanism 1030. The outer surface 1038 of each jaw 1036a, 1036b, 1036c, 1036d is formed with a spring pocket 1042 that extends annularly around the outer surface 1038. A spring 1044 is disposed in each of the spring pockets 1042 and biases the jaws 1036a, 1036b, 1036c, 1036d radially inward.

[00135] As illustrated in FIG. 48, each jaw 1036a, 1036b, 1036c, 1036d also includes an inner surface 1046 that forms angle relative to the central axis 1040. The tool -free attachment mechanism 1030 also includes a piston 1048 that is disposed along the central axis 1040. The piston 1048 includes an upper end 1050 and a lower end 1052. A frustoconical tip 1054 is affixed to, or extends from, the lower end 1052 of the piston 1048. The frustoconical tip 1054 extends into a correspondingly shaped space 1056 formed within and surrounded by the inner surfaces 1046 of the jaws 1036a, 1036b, 1036c, 1036d. The outer surface engages the inner surfaces 1046 of the jaws 1036a, 1036b, 1036c, 1036d. A spring 1060 surrounds the piston 1048 and biases the piston 1048 and the frustoconical tip 1054 in a downward direction (i.e., into the space 1056 formed within the jaws 1036a, 1036b, 1036c, 1036d). As the frustoconical tip 1054 moves in a downward direction, the outer surface 1058 of the frustoconical tip 1054 engages the inner surfaces 1046 of the jaws 1036a, 1036b, 1036c, 1036d and pushes the jaws 1036a, 1036b, 1036c, 1036d radially outward.

[00136] The tool-free attachment mechanism 1030 also includes a release pin 1062 that is attached to the upper end 1050 of the piston 1048. The release pin 1062 may be attached to a lever arm (e.g., a clamp handle of a grinder consistent with what is described herein). When the release pin 1062 is moved upward by the lever arm, the frustoconical tip 1054 of the piston 1048 moves upward and out of the space 1056 to disengage or substantially disengage from the jaws 1036a, 1036b, 1036c, 1036d. As the frustoconical tip 1054 moves out of the space 1056, the spring 1044 biases the jaws 1036a, 1036b, 1036c, 1036d radially inward, which decreases the circumferential space taken up by the jaws 1036a, 1036b, 1036c, 1036d 2. When the circumferential space taken up by the lower ends of the jaws 1036a, 1036b, 1036c, 1036d is less than an inner diameter of an aperture 1064 formed in the center of a grinding tool 1066, the grinding tool 1066 may be released or removed from the tool-free attachment mechanism 1030. As shown, the tool-free attachment mechanism 1030 also includes a spring 1068 that biases the jaws 1036a, 1036b, 1036c, 1036d in a downward direction. A user installs the grinding tool 1066 on the tool-free attachment mechanism 1030 by moving the release pin 1062 in an upward direction. By moving the release pin 1062 in a downward direction, the frustoconical tip 1054 of the piston 1048 pushes the jaws 1036a, 1036b, 1036c, 1036d in an outward direction to lock the grinding tool 1066 on the tool-free attachment mechanism 1030.

[00137] FIG. 50 illustrates another power tool, such as a grinder 1110. The grinder 1110 includes a housing 1113 including a motor housing 1114 portion in which an electric motor (not shown) having a motor shaft 1115 is located, and a gear case housing 1118 coupled to the housing 1113. The housing 1113 also includes a handle portion (not shown) extending rearward from the motor housing portion 1114, and a battery receptacle (not shown) for selectively receiving a battery pack for selectively electrically powering the motor. The grinder 1110 further includes an actuation switch, such as a paddle switch or a trigger switch, that selectively activates and deactivates the motor. The gear case housing 1118 substantially encloses and supports a portion of a drive assembly 1120. The drive assembly 1120 includes the motor, a drive gear 1121 rotatably coupled to the motor shaft 1115 for receiving torque from the motor, a driven gear 1119 rotatably driven by the drive gear 1121, and a spindle 1126 coupled for co-rotation with the driven gear 1119. The grinder 1110 further includes a tool-free attachment mechanism 1130 for selectively mounting a grinding tool 1160 (e.g., a grinding disc) on a lower portion of the spindle 1126.

[00138] The gear case housing 1118 includes an upper gear case 1122 and a lower gear case 1123 attached to the upper gear case 1122 and supports at least a portion of the drive assembly 1120. The lower gear case 1123 includes a bearing 1134 for rotatably supporting a portion of the spindle 1126, and a blade guard 1145 for enclosing the grinding tool 1160.

[00139] With respect to FIGS. 50-61, the tool-free attachment mechanism 1130 includes a spacer 1142 disposed on the spindle 1126 adjacent the bearing 1134. The tool-free attachment mechanism 1130 also includes a backing flange 1144 disposed on the spindle 1126 and keyed to a first flat region 1145 (FIG. 52) of the spindle 1126 to rotate with the spindle 1126. A spring 1146 is provided between the spacer 1142 and the backing flange 1144 configured to bias the backing flange 1144 downward from the frame of reference of FIG. 50 and FIG. 51 along the first flat region 1145 (FIG 52) of the spindle 1126. It is to be understood that the spacer 1142 and the backing flange 1144 may not move radially relative to the spindle 1126. The spacer 1142 and the backing flange 1144 rotate with the spindle 1126. Further, the backing flange 1144 only moves axially along the spindle 1126. The spring 1146 provides a force to create a clamping load in order to retain the grinding tool 1160. The spring 1146 is held in place radially by inner walls 1151, 1152 (FIG. 53) formed on the spacer 1142 and an outer wall 1153 (FIG. 56 and 57) formed on the backing flange 1144. It is to be understood that the backing flange 1144 is not removable from the spindle 1126. Specifically, the backing flange 1144 is prevented from moving too far up the spindle 1126 by the lower gear case 1122.

[00140] As shown in FIG. 51-52, the tool-free attachment mechanism 1130 further includes a flange nut 1154 disposed on the spindle 1126 adjacent the end 1156 of the spindle 1126. The flange nut 1154 is keyed to a second flat region 1158 on the spindle 1126 for co rotation with the spindle 1126. An intra flange 1162 is disposed on the spindle 1126 between the flange nut 1154 and the backing flange 1144. The intra flange 1162 fits at least partly into a cavity 1164 (FIG. 58) formed in the backing flange 1144. The intra flange 1162 is slip fit onto the spindle 1126 and rotates thereon. The end 1156 of the spindle 1126 is formed with a groove 1166 and a spring clip 1168 fits into the groove 1166 to hold the flange nut 1154 and the intra flange 1162 on the spindle 1126. The intra flange 1162 and the flange nut 1154 also prevent the back flange 1144 from slipping off of the spindle 1126. The spindle 11216 also includes a shoulder 1170 adjacent the first flat region 1145 of the spindle 1126 to prevent the intra flange 1162 from moving up the spindle 1126.

[00141] Both the flange nut 1154 and the intra flange 1162 have first and second mounting arrangements (FIGS. 60 and 61; e.g., torque features), respectively, that interface with the grinding tool 1160 during operation and installation. The first mounting arrangement includes a plurality of axially extending protrusions 1172 on the flange nut 1154 and the second mounting arrangement includes a plurality of radially extending protrusions 1174 on the intra flange 1162 that are configured to misalign with and be received within similarly shaped recesses formed on the grinding tool 1160. The flange nut 1154 supports the grinding tool 1160 during operation and the backing flange 1144 fits at least partially over the intra flange 1162 and provides clamping force. As illustrated in FIG. 59 and 60, the intra flange 1162 includes a ramp structure 1176 that cooperates with the backing flange 1144 to lift the backing flange 1144 away from the grinding tool 1160 to counteract the clamping force of the spring 1146. The ramp structure 1176 also fits into, or nests, within a complementarily-shaped ramp groove 1178 (FIG. 58) formed in an upper surface 1180 of the cavity 1164 of the backing flange 1144. The ramp structure 1176 on the intra flange 1162 includes a ball 1182 (FIG. 60) disposed within a cylindrical bore 1183 formed in the ramp structure 1176. The ball 1182 is biased outward from the cylindrical bore 1183 by a spring (not shown). The ball 1182 within the ramp structure 1176 of the intra flange 1162 cooperates with a circular detent 1184 (FIG. 58) formed in an upper surface 1186 of the ramp groove 1178 of the backing flange 1144. The ball 1182 cooperates with the detent 1184 to prevent accidental actuation of the tool-free attachment mechanism 1130.

[00142] FIG. 52 shows that the spindle 1126 include a first guide feature 1190. The backing flange 1192 include a second guide feature 1192 (FIG. 56). The flange nut 1154 includes a third guide feature 1194 (FIG. 61). The guide features 1190, 1192, 1194 may be protrusions or slots and are provided to facilitate assembly of the tool-free attachment mechanism 1130.

[00143] In order to install the grinding tool 1160 on the spindle 1126, a central aperture of the grinding tool 1160 is aligned with the protrusions 1172 on the flange nut 1154. Then, the grinding tool 1160 is slipped over the flange nut 1154 and onto the corresponding protrusions 1174 of the intra flange 1162. In the installation position, the ramp structure 1176 holds the backing flange 1144 up and out of contact with the grinding tool 1160 and removes the clamping force of the spring 1146 from the grinding tool 1160. Once the grinding tool 1160 is on the intra flange 1162, the arbor lock on the grinder 1110 is engaged to lock the spindle 1126. Then, the grinding tool 1160 and the intra flange 1162 are rotated approximately forty-five degrees (45°) counterclockwise until the ramp structure 1176 on the intra flange 1162 is aligned with the complementary shaped ramp groove 1178 formed in the backing flange 1144. Once aligned, the ramp structure 1176 on the intra flange 1162 may nest within the ramp groove 1178 of the backing flange 1144, as illustrated in FIG. 31. With the ramp structure 1176 on the intra flange 1162 nested within the ramp groove 1178 of the backing flange 1144, the spring 1146 biases the backing flange 1144 into contact with the grinding tool 1160, as shown in FIG. 33. As such, the backing flange 1144 can engage the grinding tool 1160 and provide a clamping force to hold the grinding tool 1160 in place against the flange nut 1154.

[00144] To remove the grinding tool 1160 from the spindle 1126, the arbor lock is engaged to lock the spindle 1126. Then, the grinding tool 1160 and the intra flange 1162 are rotated approximately forty-five degrees (45°) clockwise until the ramp structure 1176 on the intra flange 1162 is misaligned with the ramp groove 1178 formed in the backing flange 1144. As the ramp structure 1176 on the intra flange 1162 rotates out of the ramp groove 1178, the ramp structure 1176 on the intra flange 1162 lifts the backing flange 1144 away from the grinding tool 1160 to remove the clamping force provided by the spring 1146. Once the clamping force is removed, the aperture of the grinding tool 1160 may be re-aligned with the protrusions 1172 on the flange nut 1154 and the grinding tool 1160 may be removed from the spindle 1126. It is to be understood that the flange nut 1154 may have substantially the same shape (top plan view) of the aperture of the grinding tool 1160. On the other hand, the flange nut 1154 may be a shape (top plan view) that is slightly different from the aperture of the grinding tool 1160 to provide better clearance of the grinding tool 1160 over the flange nut 1154 during installation and removal of the grinding tool 1160 from the spindle 1126 of the grinder 1110. In case the intra flange 1162 gets jammed on the backing flange 1144, a spanner tool may be used to provide the necessary torque to rotate the intra flange 1162 on the spindle 1126.

[00145] By having a grinder 10, 110, 210, 310, 410, 510, 610, 710, 710a, 810, 910, 1110 that utilizes any of the tool-free attachment mechanisms 30, 130, 230, 330, 430, 530, 630, 730, 730a, 830, 930, 1030, 1130 the user can save both time and effort. Each of the mechanisms 30, 130, 230, 330, 430, 530, 630, 730, 730a, 830, 930, 1030, 1130 prevents the user from needing to use additional tools (e.g., a wrench) in order to remove and replace the grinding tool 60, 160, 260, 360, 460, 560, 660, 760, 760a, 860, 960, 1066, 1160 which 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 mechanisms 30, 130, 230, 330, 430, 530, 630, 730, 730a, 830, 930, 1030, 1130 increases the user’s working efficiency, as the mechanisms 30, 130, 230, 330, 430, 530, 630, 730, 730a, 830, 930, 1030, 1130 reduce the overall time between grinding tool changes, which preserves more time for the user to complete the task at hand.

[00146] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.

[00147] Various features of the invention are set forth in the following claims.