FIELD OF THE INVENTION
The present invention relates to hand-held power tools, and more particularly to angle grinders.
BACKGROUND OF THE INVENTION
Power tools, such as hand-held angle grinders, include rotating abrasive tool elements, or abrasive discs, that create debris during operation on a workpiece. Such angle grinders typically include a guard partially surrounding the abrasive disc to shield a user of the angle grinder from such debris. However, such guards are typically removable to unshroud the entire outer periphery of the abrasive disc for a grinding operation.
SUMMARY OF THE INVENTION
The invention provides, in one aspect, an angle grinder including an output shaft defining a rotational axis, a housing from which the output shaft extends, and a flange coupled to the housing and surrounding the output shaft. The angle grinder also includes a first circumferential groove defined between the flange and the housing, a first array of radially outward-extending slots in the flange and in communication with the first circumferential groove, and a keyway defined in the housing. The keyway is positioned inline with a first of the radially outward-extending slots in the first array. The angle grinder further includes a guard with a second array of radially inward-extending projections and a key positionable within the keyway. The second array of radially inward-extending projections is received in the first array of radially outward-extending slots. The key able to close the first radially outward-extending slot in the first array to prevent removal of the guard from the housing.
The invention provides, in another aspect, an angle grinder including an output shaft defining a rotational axis, a housing from which the output shaft extends, and a flange coupled to the housing and surrounding the output shaft. The angle grinder also includes a first circumferential groove defined between the flange and the housing, a first array of radially outward-extending slots in the flange and in communication with the first circumferential groove, and a guard including a second array of inward-extending projections. The inward-extending projections of the guard are configured to be received in the first array of the radially outward-extending slots. The angle grinder further includes a first stop disposed on the housing, and a second stop formed on the guard and engageable with the first stop. The second stop engages the first stop to prevent the re-alignment of the second array of radially inward-extending projections with the first array of radially outward-extending slots, which prevents the removal of the guard from the housing.
The invention provides, in another aspect, an angle grinder including an output shaft defining a rotational axis, a housing from which the output shaft extends, a guard coupled to the housing and partially surrounding the output shaft, and a guard locking flange coupled to the housing. The guard locking flange is permanently affixed to the housing and configured to axially retain the guard to the housing.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an angle grinder in accordance with an embodiment of the invention.
FIG. 2 is an exploded perspective view of the angle grinder of FIG. 1, illustrating a guard and a key for axially fixing the guard to a gear case cover of the angle grinder.
FIG. 3 is an exploded perspective view of the angle grinder of FIG. 1, illustrating a latch plate for rotationally locking the guard.
FIG. 4 is a partially assembled, perspective view of the gear case cover, guard, and key of FIG. 2, illustrating the key removed from the gear case cover.
FIG. 5 is a perspective view of the gear case cover of FIG. 2, illustrating the key in an installed position.
FIG. 6A is a partially assembled, perspective view of an angle grinder in accordance with another embodiment of the invention, illustrating a key removed from the gear case cover.
FIG. 6B is a perspective view of the angle grinder of FIG. 6A, illustrating the key in an installed position.
FIG. 7 is a cross-sectional view of the angle grinder of FIG. 6B, illustrating the key in the installed position.
FIG. 8A is a partially assembled, perspective view of an angle grinder in accordance with another embodiment of the invention, illustrating a key removed from the gear case cover.
FIG. 8B is a perspective view of the angle grinder of FIG. 8A, illustrating the key in an installed position.
FIG. 9A is a perspective view of an angle grinder in accordance with another embodiment of the invention.
FIG. 9B is an enlarged view of the angle grinder of FIG. 9A, illustrating a stop on a rotatable guard engaging a counter stop.
FIG. 10 is a perspective view of an angle grinder in accordance with yet another embodiment of the invention, illustrating a guard and a guard-locking flange.
FIG. 11 is an enlarged, cross-sectional view of an angle grinder in accordance with yet another embodiment of the invention, illustrating a roll pin installed into the gear case cover and a rotatable guard flange.
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
FIG. 1 illustrates a hand-held power tool, such as an angle grinder 100, including a housing 104 defining, collectively, a motor housing portion 114 and a gear case portion 116 mounted to a front end of the motor housing portion 114. In the illustrated embodiment, the gear case portion 116 includes a gear case 118 and a gear case cover 120 fastened to the gear case 118 with a plurality of gear case fasteners 121. The angle grinder 100 also includes an output shaft 122 extending from the gear case portion 116 along a rotational axis 126 that is perpendicular to a longitudinal axis 128 defined by the motor housing portion 114. The output shaft 122 is driven by a motor (not shown) positioned within the motor housing portion 114 and a gear train (also not shown) is positioned within the gear case portion 116 for transferring torque from the motor to the output shaft 122. A grinding or abrasive disc (not shown) can be mounted to the output shaft 122 for co-rotation therewith about the rotational axis 126.
With reference to FIG. 2, the gear case cover 120 includes a flange 130 extending therefrom and encircling the rotational axis 126. In some embodiments, the gear case portion 116 and motor housing portion 114 may be integrally formed as a single piece, with the flange 130 also being an integral piece of the housing 104. In other embodiments, the flange 130 may be a separate component and may be selectively coupled to the housing 104. The flange 130 includes an array of six radially outward-extending slots 138 and a keyway 139 coinciding or inline with a first of the slots 138. The gear case cover 120 defines a circumferential groove 134 below and adjacent the flange 130, such that the slots 138 are in communication with the circumferential groove 134. One of the slots 138 is has a width greater than the remaining slots 138 and is therefore used as an alignment slot 142 as explained in detail below. In other embodiments of the angle grinder 100, the flange 130 may include more or fewer slots 138. In addition, the keyway 139 is shaped to receive a key 141, which is used for axially retaining a guard 146 to the gear case cover 120, as explained in further detail below.
With continued reference to FIG. 2, the guard 146 partially surrounds the abrasive disc (not shown) when the disc is mounted to the output shaft 122. And, the guard 146 is rotatable relative to the gear case cover 120 to adjust the orientation of the guard 146 relative to the housing 104 and expose different regions of the abrasive disc needed for a grinding operation. The guard 146 includes an array of six radially inward-extending projections 150 and five apertures 155 positioned radially about guard 146. One of the projections 150 has a width greater than the remaining projections and is therefore used as an alignment projection 158 to be received within the alignment slot 142 in the flange 130. The projections 150 on the guard 146 are aligned with, and therefore receivable through, the slots 138 in the flange 130 when the alignment projection 158 is aligned with the alignment slot 142. After inserting the projections 150 within the slots 138, the guard 146 is lowered until the projections 150 reach the circumferential groove 134. Thereafter, the guard 146 can be rotated about the rotational axis 126 to misalign the projections 150 from the slots 138, thereby axially securing the guard 146 to the gear case cover 120. The guard 146 is thereby removable from the circumferential groove 134 only when the alignment projection 158 is re-aligned with the alignment slot 142, at which time the remainder of the projections 150 will become re-aligned with the respective slots 138.
Referring to FIG. 3, the angle grinder 100 further includes a latch plate 162 for rotationally securing the guard 146 into a desired orientation relative to the gear case cover 120. The latch plate 162 includes an actuating portion 170 and a detent member 174. A compression spring 182 is positioned between a spring seat 186 on the gear case cover 120 and biases the detent member 174 toward the guard 146. In the illustrated embodiment, the spring seat 186 is a recess and the compression spring 182 is positioned within the spring seat 186. In alternative embodiments, the spring seat may be a post and the compression spring 182 may be positioned and seated around the post. The detent member 174 is receivable in one of the five apertures 155 in the guard 146 to rotationally secure the guard 146 relative to the gear case cover 120. The latch plate 162 is biased by the spring 182 to position the detent member 174 in one of the apertures 155 upon installation of the guard 146 onto the gear case cover 120 as described above. The detent member 174 is removed from one of the apertures 155 in the guard 146 by applying a force to the actuating portion 170 of the latch plate 162 directed away from the guard 146. The applied force removes the detent member 174 from one of the apertures 155, after which time the guard 146 is free to rotate about the rotational axis 126 to a different rotational position relative to the gear case cover 120. Upon releasing the actuating portion 170, the spring 182 rebounds and pushes the detent member 174 back toward the guard 146, thereby positioning the detent member 174 into the next aperture 155 that it encounters as rotation of the guard 146 continues to a desired position.
Referring to FIGS. 4 and 5, when installed in the keyway 139, the key 141 prevents the guard 146 from being removed from the gear case cover 120. In practice, the guard 146 is installed as detailed above and then rotated to a position where none of the projections 150 block the keyway 139, as shown in FIG. 4, at which instance the keyway 139 is aligned with a slot between two adjacent projections 150. When the keyway 139 is unobscured, the key 141 can be inserted into the keyway 139. Once installed in the keyway 139, the key 141 can be secured to the gear case cover 120 via a fastener or a pin (not shown) to make it difficult for unauthorized users to remove the key 141. The fastener or pin (not shown) is installed in a hole 184 in the gear case cover 120 (FIG. 5) with a tool (e.g., a hex driver) and secured into an aligned, corresponding hole 188 in the key 141 (FIG. 4). In some embodiments, the hole 184 is oriented transverse to the rotational axis 126. When the key 141 is installed, one of the slots 138 is blocked by a flange portion 190 of the key 141 (FIG. 5), which prevents any one of the projections 150 from exiting through its designated slot 138. Therefore, the guard 146 is prevented from being removed from the gear case cover 120 at any time. However, the rotational adjustment of the guard 146 is unhindered as the key 141 includes a circumferential groove 192 aligned with the circumferential groove 134 in the gear case cover 120 with an equal thickness as the circumferential groove 134. As such, the guard 146 can freely rotate when the detent member 174 is removed from the apertures 155.
An alternate embodiment of the angle grinder 500 is shown in FIGS. 6A, 6B, and 7, with like features as the angle grinder 100 shown in FIGS. 1-5 being shown with like reference numerals. In the illustrated embodiment, the guard 146 is still rotatable about the rotation axis 126, but not removable. The guard 146 is installed in a similar fashion to the angle grinder 100, as described above. However, the key 541 does not include a hole, but instead includes a plurality of indents 543 against which a corresponding plurality of fasteners (e.g., set screws 548) are clamped using a tool (e.g., a hex driver). Each of the indents 543 includes an angled surface 544 and an adjacent bottom surface 545, as shown in FIG. 7. When the key 541 is installed in a keyway 539, the indents 543 are aligned to a plurality of holes 584 formed on a gear case cover 520. The holes 584 are threaded and each receive a set screw 548 that is inserted into one of the indents 543. In the illustrated embodiment, the set screws 548 have a conical end 547. When the key 541 is not fully installed, the conical end 547 of the set screw 548 contacts the angled surface 544. As the set screw 548 is further threaded, the conical end 547 moves along the angled surface 544, which in turn moves the key 541 further into the keyway 539. The key 541 is considered fully installed when it contacts a bottom 550 of the keyway 539 and the conical ends 547 of the set screws 548 contact both the bottom surface 545 and the angled surface 544.
FIGS. 8A and 8B illustrate an alternate embodiment of a key 541B and an alternate embodiment of a gear case cover 520B. The key 541B includes a single indent 543, which can receive one set screw 548. The set screw 548 can be received through a hole 584 in the gear case cover 520B.
An alternate embodiment of an angle grinder 300 is shown in FIGS. 9A-9B, with like features as the angle grinder 100 shown in FIGS. 1-5 being shown with like reference numerals. In the illustrated embodiment, the guard 146 is still rotatable but not removable. The guard 146 is installed in a similar fashion as detailed above with the angle grinder 100. However, the guard 146 is non-removable from the gear case cover 120 due to interaction between a first stop 393 and the guard 146. As shown in FIG. 9B, the first stop 393 has an L-shaped cross-section and is attached to the gear case cover 120 with a fastener or a pin (not shown) that is not easily removable. When installed, a second stop 394 formed on the guard 146, such as a radially outward extending projection, contacts a notch 395 defined on the first stop 393 to prevent rotation of the guard 146 past a certain degree. As a result, the guard 146 cannot be removed from the gear case cover 120, because the projections 150 are not permitted to align with their respective slots 138.
An alternate embodiment of a gear case cover 420 is shown in FIG. 10, with like features as the gear case cover 120 shown in FIGS. 1-5 being shown with like reference numerals. In the illustrated embodiment, the guard 146 is axially retained by a guard-locking flange 498. The guard locking flange 498 retains the guard 146 to the gear case cover 420 by connecting to a hub 499 on the gear case cover 420 through a pair of reverse threads, a press fit, a roll pin, or a combination of the three. In the illustrated embodiment, the guard-locking flange 498 includes a set of male reverse threads (not shown), while the hub 499 of the gear case cover 420 includes a set of corresponding female threads (not shown). If the guard locking flange 498 is installed onto the hub 499 of the gear case cover 420, the guard locking flange 498 cannot be removed and the rotatable guard 146 is axially retained. In another embodiment, the guard-locking flange 498 is press-fitted to the hub 499 of the gear case cover 420. Once press fitted, the guard-locking flange 498 cannot be removed and therefore axially retains the guard 146.
FIG. 11 illustrates an alternate embodiment of a gear case cover 620 and an alternate embodiment of a guard locking flange 698. The gear case cover 620 and the guard locking flange 698 include like features as the gear case cover 420 and the guard locking flange 498 shown in FIG. 10 being shown with like reference numerals. In the illustrated embodiment, the guard 146 is axially retained by the guard locking flange 698. To axially secure the guard 146, the guard 146 is first installed in a circumferential groove 634. Next, the guard locking flange 698 is press-fit into the gear case cover 620 over the guard 146, thus permanently affixing the guard locking flange 698 to the housing of the angle grinder. Once the guard locking flange 698 is fully installed into the gear case cover 620, a pin 652 is press-fit through a first pin opening 654 in the gear case cover 620 and then through a second pin opening 656 in the guard locking flange 698. The press-fit pin 652 subsequently prevents the removal of the guard locking flange 698 and the guard 146, while still allowing for rotation of the guard 146 in the circumferential groove 634. In other embodiments, the gear case cover 620 and the guard locking flange 698 may be threaded together before the pin 652 is inserted.
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.
Various features and advantages of the invention are set forth in the following claims.
Patent Application
20240261933
