This application relates to a guard assembly for a power tool, and in particular a guard assembly for an abrasive accessory of an angle grinder.
Angle grinders may be used for various grinding and cutting operations. Various types of grinding or cutting wheels can be used and mounted on the grinder spindle. Grinding wheel guards, such as type-27 guards, are provided for grinding operations and cover approximately 180 degrees of the wheel periphery, but leave the outer surface of the wheel substantially exposed. This allows the grinding wheel to be mounted onto the tool spindle rather easily. Conventional cutting wheel guards, such as type-1 guards provided for cutting operations, cover approximately 180 degrees of the wheel periphery and approximately half of each both surfaces of the wheel. This arrangement is needed b/c cutting wheels are more likely to break, fly off the spindle, or shatter during a cutting operation. Conventional cutting guards are thick enough to allow the user to insert the wheel inside the guard at an angle and mount the wheel onto the grinder spindle. However, such cutting guards block a substantial part of the user's field of vision over the work piece.
Typically available angle grinder guards cover or enclose approximately 180 degrees of the wheel perimeter regardless of the application they are used for. Certain applications may only require the use of a small portion of the cutting wheel to be used and exposed. Particularly, in some applications the wheel may be more prone to a burst or a kickback event. Leaving 180 degrees of the wheel exposes increases the risk to the user in such applications.
According to an embodiment of the invention, a guard assembly for an abrasive accessory of a power tool is provided. The guard assembly includes a guard shell being associated with a first surface of the abrasive accessory and secured to the power tool around an output spindle of the power tool; and a guard cover being associated with a second surface of the abrasive accessory opposite the first surface and attached to the guard shell at a pivot point having an axis that is at a distance from an axis of the spindle, the guard cover being rotatably movable with respect to the guard shell around the pivot point.
In an embodiment, the guard shell includes a guard collar configured to lock around a tool collar of the power tool located around the output spindle of the power tool.
In an embodiment, the pivot point includes a rivet rotatably attaching the guard cover to the guard shell, the rivet being located near an outer periphery of the inner guard shell.
In an embodiment, the guard cover is rotatable with respect to the guard shell between a closed position, where the guard cover covers approximately half or more of the second surface of the abrasive accessory, and an open position, where the guard cover covers less than approximately half of the second surface of the abrasive accessory.
In an embodiment, the guard assembly includes a spring member arranged to bias the guard cover into at least one of the close position or the open position with respect to the guard shell.
In an embodiment, the guard assembly includes a pivot stop arranged near the pivot point to limit a rotational movement of the guard cover with respect to the guard shell around the pivot point in the open position.
In an embodiment, the guard assembly includes a latch assembly arranged to secure the guard cover to the guard shell in the closed position.
In an embodiment, the latch assembly includes a latch coupled to the guard cover and actuated via an actuator member, and a corresponding slot in the guard shell engageable by the latch.
In an embodiment, the latch assembly includes a spring arranged to bias the latch into engagement into the slot of the guard shell.
In an embodiment, the guard shell includes a semi-disc-shaped surface facing a portion of the first surface of the abrasive accessory and the peripheral portion covering a peripheral portion of the abrasive accessory.
In an embodiment, the guard cover includes a semi-disc-shaped surface facing a portion of the second surface of the abrasive accessory in the closed position.
In an embodiment, a thickness of the guard assembly as defined between outer surfaces of the guard shell and guard cover is less than or equal to approximately 25 mm.
According to an embodiment of the invention, a power tool is provided including an output spindle driven by an electric motor; and a guard assembly as described above.
In an embodiment, the power tool includes a field case housing the electric motor and having an motor spindle; and a gear case attached to an end of the field case and housing a gearset driven by the motor spindle, the gearset supporting the output spindle to rotate with the motor spindle.
In an embodiment, the power tool includes at least one of a small angle grinder, a large angle grinder, or a saw.
According to another embodiment of the invention, a guard assembly for an abrasive accessory of a power tool is provided, including: an inner guard secured to the power tool around an output spindle of the power tool; and an outer guard secured to the inner guard at a pivot point along or in close proximity to an axis of the spindle, the outer guard being rotatably movable with respect to the inner guar around the pivot point between a retracted position, where the inner and outer guards together cover a first angular area of the abrasive accessory, and an extended position, where the inner and outer guards together cover a second angular area of the abrasive accessory larger than the first angular area.
In an embodiment, the inner guard covers approximately half or more of both surfaces of the abrasive accessory and the outer guard covers less than half of both surfaces of the inner guard in the retracted position.
In an embodiment, the outer guard is slidably positioned on the inner guard so that the inner and outer guards together cover up to approximately 270 degrees of a peripheral area of the abrasive accessory in the extended position.
In an embodiment, the pivot point includes a rivet rotatably connecting a side surface of the inner guard to a side surface of the outer guard.
In an embodiment, the inner guard includes a guard collar configured to lock around a tool collar of the power tool located around the output spindle of the power tool.
In an embodiment, the outer guard includes a first stop member projected radially inwardly towards a center of the guard assembly and the guard collar comprises a second stop member projecting radially outwardly towards the outer guard to engage the first stop member in the extended position.
In an embodiment, the guard assembly includes a lock assembly configured to secure an angular position of the outer guard with respect to the inner guard.
In an embodiment, the lock assembly is disposed on an outer periphery of the outer guard.
In an embodiment, the lock assembly includes an actuation member actuable by a user and an engagement portion extending from the actuation member around a pivot member secured to the outer guard.
In an embodiment, the inner guard includes peripheral slots engageable by the engagement member.
In an embodiment, one of the inner guard or the outer guard includes at least one guide member and the other one of the outer guard or the inner guard comprises an arcuate channel arranged to slidably received the at least one guide member therein, and the guide member travels through the channel as the outer guard is rotated with respect to the inner guard. In an embodiment, the ends of the arcuate channel provide stops for the guide member in the retracted and extended positions.
In an embodiment, the inner guard includes a guard shell associated with a first surface of the abrasive accessory and secured to the power tool around an output spindle of the power tool; and a guard cover being associated with a second surface of the abrasive accessory opposite the first surface and attached to the guard shell at a pivot point having an axis that is at a distance from an axis of the spindle, the guard cover being rotatably movable with respect to the guard shell around the pivot point.
In an embodiment, the outer guard is secured to the guard cover.
According to an embodiment, a power tool is provided including an output spindle driven by an electric motor; and a guard assembly as described above.
In an embodiment, the power tool includes a field case housing the electric motor and having an motor spindle; and a gear case attached to an end of the field case and housing a gearset driven by the motor spindle, the gearset supporting the output spindle to rotate with the motor spindle.
In an embodiment, the power tool includes at least one of a small angle grinder, a large angle grinder, or a saw.
In the accompanying drawings which form part of the specification:
Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
The following description illustrates the claimed invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the disclosure, describes several embodiments, adaptations, variations, alternatives, and uses of the disclosure, including what is presently believed to be the best mode of carrying out the claimed invention. Additionally, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or 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.
In an embodiment, angle grinder 10 includes a housing 12 having a handle portion 14, a field case 16, and a gear case 18. The handle portion 14 in an embodiment is fixedly attached to a first end 20 of the field case 16 and the gear case 18 is fixedly attached to a second end 22 of the field case 16. The handle portion 14 in an embodiment supports a power switch (not shown) and associated components arranged to supply power from a power source (e.g., a power cord, now shown, attached to the end of the handle portion 14) to a motor (not shown, disposed within the field case 16). The power switch, in an embodiment, is coupled to a trigger switch 28. The handle portion 14 may also support a particle separation assembly (now shown) that separates dust particles and contamination out of outlets 26. The motor includes a motor spindle (not shown) that extends into the gear case 18 for driving a gearset supported therein. In an embodiment, a wheel spindle 34 extends from gear case and is rotatably driven by the motor spindle through the gearset. The axis of rotation of motor spindle is generally perpendicular to the axis of rotation of the wheel spindle 34. A grinder wheel (not shown) is preferably selectively attachable to the wheel spindle 34 and is rotatably driven thereby.
In an embodiment, gear case 18 includes a tool collar (or neck) 36 disposed around the wheel spindle 34. The tool collar 36 provides a mounting platform for securely receiving the guard assembly 100. The wheel spindle 34 rotatably extends through the tool collar 36. The tool collar 36 may include, in an embodiment, an annular track (or groove) 38 extending about its circumference. As explained below, the annular track 38 is used for locking a locking element of the guard assembly 100 around the tool collar 36.
A first aspect of the invention is described herein with reference to
Referring to
With continued reference to
The guard assembly 100, in this embodiment, is provided with an inner guard rivet 140, which provides a pivoting attachment point between the inner guard cover 120 and the inner guard shell 112. In an embodiment, rivet 140 is provided near an outer periphery of the inner guard shell 112, preferably closer to the tool body 10.
In yet a further embodiment, as shown in the zoomed-view of
The embodiment of the invention described above provides a guard assembly that covers at least approximately half of each surface of the abrasive wheel. This arrangement provides more safety for the user, particularly in a cutting operation, and makes it easier for the user to install or remove the abrasive wheel.
Moreover, according to the described embodiment, the guard may be moved to an “open” position by the user prior to installing or removing the abrasive wheel. Thus, the overall thickness of the guard assembly may be substantially reduced in comparison to conventional stationary type-1 guards that must be sufficiently thick to allow insertion and installation of the abrasive wheel within the inner space of the guard.
In an embodiment, as shown in
While this aspect of the invention described above is made with reference to a guard assembly 100 including an outer guard 130, it must be understood that the guard assembly 100 without an outer guard 130 is within the scope of the above-described aspect of the invention. In other words, a two piece guard including a guard shell 112, a guard cover 120, and a rivet 140 that allows the user move the guard cover 120 between “open” and “closed” positions as needed is within the scope of the above-described aspect of the invention. It is also noted that while this embodiment discloses a latch assembly 150 including a spring-loaded latch 152, any known fastening means for attaching/detaching the inner guard cover 120 may be alternatively utilized.
A second aspect of the invention relating to the outer guard 130 is described herein with reference to
In an embodiment, guard assembly 100 is provided with outer guard 130, which is adjustably rotatably moveable between a retracted position and an extended position to allow the user to cover from approximately 180 degree to 270 degrees of the outer periphery of the abrasive wheel. This arrangement provides the user with the flexibility to expose a smaller portion of the abrasive wheel, particularly in cutting applications, as desired by the user.
In the illustrated example of
In the fully extended position as shown in
In an embodiment, the outer guard 130 is further provided with a first stop member 164 radially projecting from an inner surface of the outer guard 130, as shown in
Lock assembly 170 for the outer guard 130 of the guard assembly 100 is described herein with reference to
Referring now to
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
This application claims the benefit of U.S. Provisional Application No. 62/146,576 titled “Guard Assembly for Angle Grinder,” filed Apr. 13, 2015, content of which is incorporated herein by reference in its entirety.
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