JP7549352B2 - Rotary grinding tool with protective cover attached shaft - Google Patents

Description

The present invention relates to a rotary abrasive tool, and in particular to a rotary abrasive tool that can efficiently abrade the surface to be abraded in areas that are in the shadow of installed accessories and that hinder the abrasive work.

Polishing with a rotary polishing tool is performed by rotating a polishing disk with a polishing member attached by a drive motor and pressing the surface of the polishing member against the surface to be polished. Various polishing members made of fiber materials or sponges are used as buffs to perform buff polishing (see, for example, Patent Document 1). Rotary polishing tools are classified into vertical types in which the drive motor stored in the main body is arranged vertically, and horizontal types in which the drive motor is arranged horizontally. In the vertical type, the output shaft of the drive motor and the rotating shaft of the polishing disk are connected in the same direction, while in the horizontal type, the output of the drive motor and the rotating shaft of the polishing disk are connected in an orthogonal direction using a bevel gear or the like. However, in both types, the output of the drive motor is transmitted to the polishing disk by the rotating shaft. Such rotary polishing tools are widely used for buffing to give a surface gloss as a finishing touch to painted surfaces, and are often used as polishers for the surfaces of automobile bodies.

The surface to be polished, the body surface of an automobile, is fitted with exterior parts such as door mirrors, doorknobs, and license plates, and there are areas that are shaded by these exterior parts. In order to polish these areas, it is necessary to press the polishing member attached to the polishing plate against the surface to be polished that is shaded by the exterior parts, while avoiding the exterior parts. In this case, if the polishing plate is large (for example, with a diameter of about 150 mm or more), it is difficult to insert the polishing plate with the polishing member attached into the area that is shaded by the exterior parts, and polishing plates of about 50 to 100 mm are used, but because the distance between the rotating shaft connected to the center of rotation of the polishing plate and the edge of the polishing plate is short, contact between the shaft and the exterior parts is likely to occur during the polishing work, and great care must be taken to perform the polishing work while avoiding damage to the exterior parts due to contact. When the exterior part is large, such as a door mirror, as shown in FIG. 6, a shaft extension 9 is attached to a rotating shaft 6 that transmits the output of the drive motor to a polishing machine 7, and the surface paint of the area that is in the shadow of the door mirror 100 is polished while avoiding the door mirror 100, which is an exterior part that obstructs the polishing work. In this case, the surface of the door mirror 100 is covered and protected with a protective member 101 during the polishing work so that the shaft extension 9 and the door mirror 100 do not come into contact and get damaged, but in reality it is difficult to completely prevent damage to the door mirror 100 due to contact.

The inventors conducted extensive research to prevent damage caused by contact between the exterior parts and the rotating shaft during such polishing work, and came up with this invention.

Patent No. 6580086

The objective of the present invention is to provide a rotary grinding tool that can prevent damage to exterior parts caused by contact with a rotating shaft during grinding of a surface to be ground that has areas shaded by installed exterior parts.

The rotary grinding tool of the present invention is characterized in that a slidably rotatable cylindrical protective cover made of synthetic resin is attached to the side of a rotating shaft that transmits the output of a drive motor to a grinding disk on which a grinding member is attached. It is preferable that the cylindrical protective cover is slidable by attaching it with a gap between the side of the rotating shaft and the inner surface of the cylindrical protective cover.

The rotating shaft is preferably a rotating shaft extended by a shaft extension part to which one or more extension parts are connected. Furthermore, it is preferable that these extension parts have a male thread at the center of the rotation axis on one end face and a female thread at the center of the rotation axis on the other end face along the axial direction, and a fastening rod insertion hole is provided near one end face in a direction perpendicular to the axial direction, and the fastening rod insertion hole is used to insert a wrench rod or the like used as a fastening rod to rotate the connected extension parts and fasten the provided male and female threads.

In addition to mounting the cylindrical cover so that it can slide and rotate by providing a gap as described above, it can also be made slidable and rotatable by using a sliding synthetic resin with a small coefficient of friction, by interposing a lubricant between the side of the resin rotating shaft and the inner surface of the cylindrical protective cover, or by providing multiple protrusions on the inner surface of the cylindrical protective cover in a direction perpendicular to the rotation axis. However, a structure that allows sliding and rotation by providing a gap is a simple and inexpensive structure.

The cylindrical protective cover attached to the rotating shaft attached to the rotary grinding tool of the present invention is made of synthetic resin and is slidably rotatable. Therefore, even if the rotating shaft comes into contact with the exterior part during grinding of the surface to be ground, which has a shaded area due to the installed exterior part, the cylindrical protective cover rotates and slides, so that the exterior part is not impacted and no damage occurs. The rotating shaft is also not damaged. In particular, the cylindrical protective cover is made of synthetic resin, which has a low surface hardness and reduces the impact when it comes into contact with the exterior part.

In addition, by connecting an extension part to the rotating shaft to make an extended rotating shaft, polishing work on areas shaded by exterior parts becomes easier. Furthermore, since the extended rotating shaft is extended by a shaft extension part to which one or more extension parts are connected, the length of the shaft can be adjusted to suit various situations in which exterior parts are attached.

FIG. 2 is a perspective view of a rotary grinding tool having a cylindrical protective cover attached to a rotating shaft. FIG. 2 is a perspective external view of a rotary grinding tool having a cylindrical protective cover attached to a rotating shaft extended by a shaft extension portion. FIG. 2 is a cross-sectional view of a rotating shaft equipped with a cylindrical protective cover; FIG. 13 is an explanatory diagram of an extension part provided with a fastening rod insertion hole. FIG. 13 is an explanatory diagram of an extension part having fastening notches for the clamping surface of a wrench. An explanatory diagram of a conventional polishing process for areas shaded by door mirrors using an extended rotating shaft.

The following describes in more detail the embodiment of the present invention with reference to the drawings.

Figure 1 is a perspective view of a rotary polishing tool 10 according to an embodiment of the present invention. It is a horizontal type rotary polishing tool in which a drive motor 3 is stored sideways in a main grip 2 installed at the rear of a main body 1. The output of the drive motor 3 is redirected in an orthogonal direction by a bevel gear or the like inside the main body 1 and transmitted by a rotating shaft 6 to a polishing plate 7 to which a polishing member 8 such as a buff is attached. The polishing member 8 is detachably attached to the polishing plate 7 by a hook-and-loop fastener, and can be replaced depending on the type and condition of the surface to be polished. A cylindrical protective cover 20 made of synthetic resin that can slide and rotate is attached to the rotating shaft 6. The cylindrical protective cover 20 is attached with a gap between its inner surface and the side of the rotating shaft 6, allowing it to slide and rotate.

When using the rotary grinder 10 to grind the painted surface of the vehicle body in a shaded area under the doorknob of an exterior part, by inserting the turntable 7 with the grinding member 8 attached under the doorknob, the rotating shaft 6 with the cylindrical protective cover 20 attached may come into contact with the doorknob even when the main grip 2 and sub-grip 4 are used to perform the work. In this case, the cylindrical protective cover 20 does not come into contact with the rotating shaft 6, but comes into contact with the cylindrical protective cover 20, which rotates in a sliding manner, so that no large impact is given to the doorknob and damage to the doorknob is avoided.

As mentioned above, when polishing a place that is in the shadow of a large exterior part such as a door mirror, the polishing work can be made easier by extending the rotating shaft 6 of the rotary polishing tool 10 with a shaft extension 9, which is made by connecting extension parts 9A, B, and C to the rotating shaft 6, as shown in Figure 2. In this case, in addition to the cylindrical protective cover 20 attached to the rotating shaft 6, a cylindrical protective cover 21 can also be attached to the shaft extension 9 to prevent damage to the exterior part. In addition, as shown in Figure 6 above, the exterior part may be covered with a protective member, or the protective member may be omitted.

As shown in Figure 2, the cylindrical protective cover 21 attached to the shaft extension 9 is divided into cylindrical protective covers 21A, B, and C of the same length as the extension parts 9A, B, and C that make up the shaft extension 9. This allows one or more extension parts to be selected and connected according to the size of the exterior parts, etc., to adjust the length of the shaft extension 9.

In addition, in FIG. 2, an example is shown in which cylindrical protective covers 20 and 21 are attached to the entire extended rotating shaft consisting of the rotating shaft 6 and the shaft extension 9, but depending on the size, shape, and other conditions of the exterior parts, it is not necessarily necessary to cover the entire extended rotating shaft, and only the parts that are likely to come into contact with the shaft and the exterior parts may be covered and attached. For example, it is possible to omit the cylindrical protective cover 20, with only the cylindrical protective cover 21 attached to the shaft extension 9. Furthermore, in FIG. 2, an example is shown in which the cylindrical protective cover 21 is attached in parts, but the entire covering part may be one cylindrical protective cover.

The cylindrical protective covers 20 and 21 attached to the rotating shaft 6 and the shaft extension 9 are attached so as to be slidably rotatable. To do so, they are attached so as to have a gap 30 between the side of the rotating shaft 6 or the extended rotating shaft 9 and the inner surface of the cylindrical protective covers 20 and 21, as shown in the cross-sectional explanatory diagram shown typically in FIG. 3. In FIG. 3, the gap 30 is shown typically, and it is sufficient that the gap is 0.5 mm or less and that each is loosely attached so as to be slidably rotatable. In addition, it is also possible to make the cylindrical protective covers 20 and 21 slidably rotatable by interposing a lubricant between the side of the rotating shaft 6 or the extended rotating shaft 9 and the inner surface of the cylindrical protective covers 20 and 21, or by providing multiple ridges parallel to the rotation direction on the inner surface of the cylindrical protective covers 20 and 21.

Figure 4 shows extension parts 9A, 9B, and 9C for extending the rotating shaft 6, and one or more of these parts can be connected to form the shaft extension 9. A male screw 91 is provided at the center of the rotation axis of one end face of each extension part, and a female screw 92 is provided at the center of the rotation axis of the other end face along the axial direction. By fastening these screws to each other, each extension part can be connected to form the shaft extension 9, and the male screw 91 provided on the extension part 9A can be fastened to the female screw of the rotating shaft 6 (not shown) to extend the shaft. Then, the male screw 71 provided on the grinding disk 7 is fastened to the female screw 92 provided on the extension part 9C, and the grinding disk 7 is attached to the shaft extension 9. Although the grinding member 8 is not shown in Figure 4, the grinding member 8 can be attached to the grinding disk 7 detachably by hook-and-loop fastener as described above, so that it can be attached either after or before the grinding disk 7 is attached to the shaft extension 9.

When the cylindrical protective cover 21 is divided as shown in FIG. 2, the cylindrical protective cover 21 may be attached in parallel with the connection of the extension parts 9A, 9B, and 9C, or it may be attached after each extension part is connected and before the polishing disk 7 is attached. When the cylindrical protective cover is not divided but is a single protective cover, it is attached after each extension part is connected and before the polishing disk 7 is attached.

The extension parts 9A, 9B, and 9C each have a fastening rod insertion hole 93 near one end face. This insertion hole is used to insert a fastening rod and fasten the screw when connecting each extension part to each other or to a rotating shaft. This fastening rod insertion hole 93 is provided in place of the notch 94 for fastening with a screw spanner provided in the conventional extension parts 9a, 9b, and 9c shown in FIG. 5, and can be fastened with a metal rod or a screwdriver of an appropriate thickness without using a spanner with a gripping surface that matches the size of the notch. In addition, it is preferable to provide the fastening rod insertion hole 93 near one end face where the male screw is provided, avoiding intersection with the female screw hole. In addition, if a notch for fastening with a spanner is provided for screw connection, the corner of the notch end may hit the inner surface of the cover during sliding rotation of the cylindrical protective cover 21 attached to the shaft extension part 9, and the sliding rotation may not be smooth, so it is preferable to provide it as an insertion hole.

As the synthetic resin constituting the cylindrical protective cover 20, various synthetic resins can be used, and thermoplastic resins and thermosetting resins can be molded into a cylindrical shape by a well-known molding method corresponding to each resin and used as a cylindrical protective cover. Examples of thermoplastic resins include polyamide resins such as nylon 6 and nylon 66, polyolefin resins such as polyethylene and polypropylene, polyester resins such as PET and PBT, polystyrene-based resins such as polystyrene, ABS, AS, AAS, and AES, vinyl chloride resins, polycarbonate resins, acrylic resins, polyacetal resins, fluororesins such as polyfluoroethylene, polyether resins such as PEEK, PEI, and PEK, thermoplastic polyurethane resins, and thermoplastic styrene butadiene resins, and examples of thermosetting resins include epoxy resins, unsaturated polyester resins, diallyl phthalate resins, phenolic resins, polyurethane resins, and silicone resins. In addition, FRTP and FRP, which are synthetic resins reinforced with fiber such as glass fiber and carbon fiber, can also be used.

As mentioned above, a simple method for mounting a cylindrical protective cover made of synthetic resin on a rotating shaft so that it can slide and rotate is to provide a gap between the inner surface of the cylindrical protective cover and the side of the rotating shaft to allow for sliding and rotation. It is also possible to use a sliding synthetic resin with a small friction coefficient, such as fluororesin, ultra-high molecular weight polyethylene, or polyacetal resin, to interpose a lubricant between the inner surface of the cylindrical protective cover and the side of the rotating shaft, or to provide multiple ridges parallel to the direction of rotation on one of the surfaces.

REFERENCE SIGNS LIST 1 Main body 2 Main grip 3 Driving motor 4 Sub-grip 6 Rotating shaft 7 Polishing disk 8 Polishing member 9 Shaft extension 9A, B, C Extension parts 9a, b, c Extension parts (conventional example)
91 Male thread 92 Female thread 93 Fastening rod insertion hole 94 Fastening notch 10 Rotary grinding tool 20, 21 Cylindrical protective cover 30 Gap 100 Door mirror 101 Protective member

Claims (4)

A rotary grinding tool comprising a rotating shaft which transmits the output of a drive motor to a grinding disk having a grinding member attached thereto, and a cylindrical protective cover which is made of synthetic resin and which is slidably rotatable relative to the rotating shaft , and which is fitted to the side of the rotating shaft and which is capable of sliding and rotating relative to the rotating shaft when the cylindrical protective cover comes into contact with an exterior part placed on a surface to be ground during grinding operation, thereby preventing damage to the exterior part .
The rotary grinding tool according to claim 1, characterized in that the cylindrical protective cover is attached with a gap between the side surface of the rotating shaft and the inner surface of the cylindrical protective cover. The rotary grinding tool according to claim 1 or 2, characterized in that the rotating shaft is extended by a shaft extension part to which one or more extension parts are connected. The rotary grinding tool according to claim 3, characterized in that the extension part has a male thread at the center of the rotation axis of one end face and a female thread at the center of the rotation axis of the other end face along the axial direction, and a fastening rod insertion hole is provided near one end face in a direction perpendicular to the rotation axis direction of the rotating shaft.

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