Anti-vibration grinding device with hub and spring

Abstract

The present invention relates to an abrasive finishing article with an anti-vibration hub design to suppress vibrations as grinding is performed.

Description

[Technical Field]

[0001] The present invention generally relates to an abrasive finishing article with a spring-equipped anti-vibration hub design combined with a grinding device for attachment to a suitable power tool. The invention has a vibration-damping function to suppress vibrations when grinding is performed, and also helps the abrasive finishing article to firmly grind the surface. Furthermore, the grinding device can be attached to a power tool without a hub, as the arbor can be used as a universal 7 / 8-inch circular arbor. [Background technology]

[0002] Abrasive grinding devices are commonly used to grind the surfaces of various materials. Conventional grinding devices easily generate vibrations due to contact friction. Furthermore, although the device is fixed when attached to a suitable power tool, it can easily create angles between the grinding device and the surface, making it difficult to grind the surface properly. Angular grinding surfaces can cause uneven wear on the grinding device, which can shorten the life of the grinding device and reduce work performance, thereby requiring extra steps to complete the job. Summary of the Invention

[0003] The present invention provides a solution to the above problem. A hub is attached to the grinding wheel. The hub biases the grinding wheel downward. The hub is rotated by a suitable device, such as a power tool, thereby driving the grinding wheel in a circular motion. The grinding wheel thus abuts the object being ground, but may move upward when force is applied to the grinding wheel. A spring disposed between the head of the upper hub and the grinding wheel flexes and damps vibrations by isolating movement from the grinding device. The spring also has limited deflection when compressed, allowing the user to tilt the grinding device, thereby allowing the user to firmly grind the surface. This helps the grinding device wear evenly, thereby extending the device's lifespan. [Brief explanation of the drawings]

[0004] [Figure 1] FIG. 2 is a top perspective view of the grinding device. [Figure 2] FIG. 2 is a bottom perspective view of the grinding device. [Figure 3] FIG. 2 is an exploded view of the grinding device. [Figure 4] FIG. 2 is a top view of the grinding device. [Figure 5] FIG. 10 is a top view of the lower flange of the hub. [Figure 6] FIG. [Figure 7] FIG. 1 is an isometric view of the unattached upper and lower hubs. DETAILED DESCRIPTION OF THE INVENTION

[0005] FIG. 1 shows a grinding device 10 having a hub 12 and a grinding wheel 20. The hub attaches to the arbor or spindle of a power tool and rotates the grinding wheel 20. The grinding wheel has a central dome portion 22 and an outwardly extending rim 24. The concave surface formed by the central dome portion creates a space below the flange that is below the grinding wheel but does not interfere with the grinding wheel's contact with the workpiece. As can be seen in the bottom view of FIG. 2, the hub 12 extends through the grinding wheel so that the hub is attached to the grinding wheel, as will be described in more detail. The underside of the grinding wheel has an abrasive surface 26. The abrasive surface may be any suitable abrasive surface, such as a diamond abrasive surface. The grinding wheel is biased downward against the hub by any suitable means, such as a damper, wave spring, coil spring, or disc spring. A biasing device preferably surrounds the hub and extends between the upper flange of the hub 12 and the upper surface of the grinding wheel.

[0006] As shown in Figure 3, the hub has an upper flange 14 and a lower flange 18. The hub body 16 extends between the upper and lower flanges and through an opening in the grinding wheel. The hub body is longer than the thickness of the plate forming the grinding wheel, allowing the hub 12 to move relative to the grinding wheel 20. A spring 30 abuts the underside of the upper flange 14 and the upper surface of the grinding wheel. The hub 12 can move relative to the grinding wheel 20, and the spring 30 presses the grinding wheel against the lower flange 18.

[0007] 3 also demonstrates how the hub 12 is attached to the grinding wheel 30. The lower flange 18 may be a nut that releasably connects to a bolt that forms the body 16 and the upper flange 14 of the hub. The nut may be attached to the bolt, which may be attached to an arbor or spindle by any suitable means, such as by mating threads. For example, the external threads on the bottom of the bolt may be attached to the internal threads of the nut, as described below, and the internal threads of the bolt may attach to the arbor or spindle.

[0008] The hub 12 can be keyed to the grinding wheel 20 so that when driven by an arbor or spindle, the rotational motion of the hub can be imparted to the grinding wheel. The hub body can have a polygonal cross-sectional shape, such as a hexagon or octagon, with the opening in the grinding wheel having a corresponding shape. Another way to key the hub to the grinding wheel is to provide a protrusion on the top surface of the lower flange that fits into an extension of the opening in the grinding wheel, as described below.

[0009] To assemble the hub onto the grinding wheel, the projections are aligned with the opening extensions and inserted into the opening extensions from the underside of the grinding wheel. The spring fits around the body of the hub, and then the threads 36, FIG. 6, are threaded onto the threads of the lower hub 18. The spring is secured between the head of the upper hub 14 and the grinding device 20, as shown in FIG. 2.

[0010] Figure 4 clearly shows the central opening 28 of the grinding wheel, which has a main opening for receiving the main body of the hub and two extensions that receive the protrusions on the lower flange of the hub. Figure 5 shows the top surface of the lower flange 18. Protrusions 32 extend upward from the top surface. The size and shape of the protrusions 32 are complementary to the extensions on the central opening of the grinding wheel to prevent relative rotation between the hub and the grinding wheel. Therefore, when driven by a suitable device such as a power tool, the hub drives the grinding wheel.

[0011] Figures 6 and 7 show one possible construction of the hub. A bolt forms the upper flange 14 and body 16 of the hub. A lower flange 18 is formed by a nut and is attached to the bolt by mating internal threads 34 with the external threads 36 of the bolt. The top of the bolt has internal threads 38 for attachment to the spindle or arbor of a power tool.

[0012] To perform the vibration tests, four identical grinding wheels were prepared, but with different hubs. The first two grinding wheel samples had a conventional fixed hub. The other two grinding wheel samples were loaded with the hub of the present invention equipped with a spring. The samples were then appropriately balanced on a balancing machine. After preparation, the vibration was tested using a vibrometer attached to an angle grinder loaded with the sample grinding wheels. The tester then turned on the angle grinder and firmly ground the material surface for a set period of time. The same test was performed on all grinding wheel samples. The vibrometer recorded acceleration values ​​in m / s for each test in the x, y, and z directions. 2 A lower value in each direction means less vibration affected the angle grinder in each direction. The table below provides the average acceleration in each direction for each of the four different tests.

[0013] Ability of the grinding wheel to move relative to the hub

[0014] [Table 1]

[0015] The above results show that when the grinding device is not properly balanced (results in row 2 of the table), the present invention damps vibrations better. When the grinding device is well balanced (results in row 1 of the table), the present invention results in lower vibrations.

[0016] The following table provides example data including maximum and minimum values ​​in all x, y, and z directions for samples balanced at 2.5 g / mm: As shown in the table, the maximum acceleration values ​​for the grinding wheels of the present invention are, on average, about 15% lower, even for the well-balanced grinding wheel samples.

[0017] [Table 2]

Claims

1. 1. A grinding device comprising: A grinding wheel; a hub attached to the grinding wheel, the hub being movable relative to the grinding wheel in an axial direction of the hub.

2. The grinding device of claim 1 , wherein the hub comprises an upper flange, a lower flange, and a body extending between the upper and lower flanges.

3. The grinding device of claim 2 , wherein the hub is biased downwardly relative to the hub.

4. The grinding device of claim 2 further comprising a spring between the upper flange and the top surface of the grinding wheel.

5. 5. The grinding device of claim 4, wherein the spring is a wave spring.

6. The grinding device of claim 1 further comprising an abrasive surface on a lower surface of the grinding wheel.

7. The grinding device of claim 2 , wherein the hub comprises a bolt forming the upper flange and body, and a nut forming the lower flange releasably connected to the bolt.

8. The grinding device of claim 7 , wherein the bolt has external threads that mate with internal threads of the nut.

9. The grinding device of claim 8 , wherein the bolt has internal threads configured to mate with a power tool.

10. the hub is biased downwardly relative to the hub by a biasing member; The grinding device of claim 1 , wherein an upper end of the biasing member is fixed relative to the hub, and a lower end of the biasing member abuts the grinding wheel.

11. The grinding device of claim 1 , wherein the biasing member is a wave spring.

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