Disc grinder

Abstract

To provide a disc grinder that prevents the operator from coming into contact with the grinding disc. [Solution] The disc grinder 1 of the present invention polishes or grinds a workpiece by pressing a rotating polishing disc 2 against the workpiece. The disc grinder 1 is equipped with a guard mechanism 8 to prevent the operator from coming into contact with the polishing disc 2. The guard mechanism 8 comprises a pair of supported members 30, 30 and a first connecting member 31. The pair of supported members 30, 30 each extend in the front-rear direction and are spaced apart in the left-right direction. The first connecting member 31 extends in the left-right direction and connects the front ends of the pair of supported members 30, 30. At least the first connecting member 31 in the guard mechanism 8 is located radially outward of the polishing disc 2 in a plan view.

Description

Technical Field

[0001] The present invention relates to a disk grinder which is a portable tool.

Background Art

[0002] FIG. 6 is a perspective view showing the configuration of a conventional disk grinder 101 disclosed in Non-Patent Document 1. The disk grinder 101 includes a polishing disk 102, a main grip 103, a sub grip 104, and a switch 105. An operator holds the main grip 103 and the sub grip 104 with the right hand and the left hand respectively, and presses the switch 105 with the right hand to rotate the polishing disk 102 by a motor (not shown). By pressing the rotating polishing disk 102 against a workpiece, the workpiece can be grinded or polished.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional disk grinder 101, when grinding or polishing a workpiece, there is a risk that an accident may occur in which an operator is injured by contacting the polishing disk 102.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a disk grinder capable of preventing an operator from contacting a polishing disk. [Means for solving the problem]

[0006] To achieve the above objectives, the present invention encompasses the subject matter described in the following sections.

[0007] Item 1. A disc grinder that polishes or grinds a workpiece by pressing a rotating abrasive disc against the workpiece, It is equipped with a guard mechanism to prevent the worker from coming into contact with the polishing disc, The guard mechanism comprises a pair of supported members and a first connecting member, The pair of supported members each extend in the front-to-back direction and are arranged with a gap between them in the left-to-right direction. The first connecting member extends in the left-right direction and connects the front ends of the pair of supported members. In the guard mechanism, at least the first connecting member is located radially outward (hereinafter referred to as radially outward) of the polishing disc in a plan view.

[0008] Item 2. The disc grinder according to Item 1, wherein the guard mechanism comprises a second connecting member extending in the left-right direction and connecting the intermediate portions of the pair of supported members.

[0009] Item 3. Equipped with a grinder body and a disc guard, The grinder body has a built-in motor for rotating the grinding disc. The polishing disc is rotatably suspended from the grinder body, The disc guard comprises an upper guard portion that is arc-shaped in plan view and an outer guard portion that extends downward from the outer circumference of the upper guard portion. The inner circumference of the upper guard portion is attached to the outer circumference of the grinder body such that the upper guard portion is located above the rear region of the polishing disc and the outer guard portion is located radially outside the rear region of the polishing disc, so that the front region of the polishing disc is exposed and not covered by the disc guard. The disc grinder according to item 1 or 2, wherein the pair of supported members are supported by the upper guard portion such that at least the first connecting member is located radially outward of the front region of the polishing disc in the guard mechanism.

[0010] Item 4. The disc grinder according to Item 3, wherein the pair of supported members are supported by the upper guard portion so that the front-rear position of the first connecting member can be changed.

[0011] Item 5. The disc guard comprises a first support mechanism for supporting one of the supported members and a second support mechanism for supporting the other supported member. The first support mechanism and the second support mechanism each comprise a member to be inserted and a bolt, The inserted member is fixed to the surface of the upper guard portion and has a cavity extending in the front-rear direction. The bolt is screwable into the through hole formed in the member to be inserted. In each of the first and second support mechanisms, with the supported member inserted into the cavity, the bolt is screwed into the through hole, and the tip of the bolt extending into the cavity presses against the supported member, thereby supporting the pair of supported members on the upper guard portion. The disc grinder according to item 4, wherein in each of the first support mechanism and the second support mechanism, the front-rear position of the first connecting member can be changed by loosening the screwing of the bolt into the through hole and releasing the pressure of the tip of the bolt on the supported member. [Effects of the Invention]

[0012] According to the present invention, it is possible to prevent the worker from coming into contact with the polishing disc. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of a disc grinder according to one embodiment of the present invention, as seen from the right side. [Figure 2] The perspective view which shows the state which looked at the disk grinder which concerns on one Embodiment of this invention from the left side. [Figure 3] The plan view of the disk grinder which concerns on one Embodiment of this invention. [Figure 4] The bottom view of the disk grinder which concerns on one Embodiment of this invention. [Figure 5] The schematic diagram which shows an example of the circuit structure for driving a motor. [Figure 6] The perspective view which shows the structure of the conventional disk grinder.

MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit thereof

[0015] Fig. 1 is a perspective view showing the state of the disk grinder 1 according to one embodiment of the present invention as viewed from the right side. Fig. 2 is a perspective view showing the state of the disk grinder 1 as viewed from the left side. Fig. 3 is a plan view of the disk grinder 1. Fig. 4 is a bottom view of the disk grinder 1. J

[0016] The disk grinder 1 according to one embodiment of the present invention is a hand-held power tool, and includes a polishing disk 2, a grinder main body 3, a main grip 4, a sub grip 5, a switch 6, a disk guard 7, and a guard mechanism 8. An operator performs an operation of polishing or grinding a workpiece by pressing the rotating polishing disk 2 against the workpiece. In the present application, the "radial direction of the polishing disk 2" is referred to as the "radial direction". Also in the present application, on the premise that the direction parallel to "one radial direction A (Fig. 4)" is the "front-rear direction" and the direction parallel to "two radial directions B (Fig. 4)" orthogonal to "one radial direction A" is the "left-right direction", the terms "front", "rear", "left", and "right" are described.

[0017] The polishing disc 2 is a disc with a circular outer circumference. The polishing disc 2 is positioned below the grinder body 3 and is suspended from the grinder body 3 so as to be rotatable around its central axis 2a. The polishing disc 2 is made of, for example, abrasive grains made of aluminum oxide, zirconium oxide, etc., molded using a thermosetting resin such as bakelite (industrial grinding wheel), or abrasive grains similar to those described above bonded to a base material such as vulcanized fiber (abrasive cloth paper disc).

[0018] The main grip 4 extends to the rear from the grinder body 3, and the sub-grip 5 extends to the left from the grinder body 3. The operator uses the disc grinder 1 by gripping the main grip 4 with their right hand and the sub-grip 5 with their left hand. The sub-grip 5 may also extend to the right from the grinder body 3. In this case, the operator uses the disc grinder 1 by gripping the main grip 4 with their left hand and the sub-grip 5 with their right hand.

[0019] Switch 6 is located on the main grip 4, and the operator can switch between the on and off states by operating the switch 6 with the fingers of the hand gripping the main grip 4. In this embodiment, the switch 6 is located on the underside of the main grip 4, but the position of the switch 6 is not particularly limited as long as it is in a position where the operator can operate it. For example, the switch 6 may be located on the sub-grip 5. In this case, the operator can switch between the on and off states by operating the switch 6 with the fingers of the hand gripping the sub-grip 5. It is also preferable that the switch 6 is a paddle switch that is on only when pressed and always off when not pressed.

[0020] The grinder body 3 has a built-in motor 10 (Figure 5, described later) that rotates the abrasive disc 2. The motor 10 is a rotational power source that is either an electric motor or a pneumatic fluid machine. When switch 6 is turned on, power is supplied to the motor 10, and the motor 10 drives to rotate the abrasive disc 2. When switch 6 is turned off, power is no longer supplied to the motor 10, the motor 10 stops driving, and the rotation of the abrasive disc 2 stops.

[0021] Figure 5 is a schematic diagram showing an example of a circuit for driving the motor 10. In the example shown in Figure 5, the motor 10 is a universal motor and is driven by power supplied from the power supply 11. Switch 6 is provided between the power supply 11 and the motor 10. When switch 6 is turned ON, power from the power supply 11 is supplied to the motor 10, driving the motor 10 and rotating the polishing disc 2. When switch 6 is turned OFF, power is no longer supplied from the power supply 11 to the motor 10, the motor 10 stops driving, and the rotation of the polishing disc 2 stops. The power supply 11 is provided in the grinder body 3 or an external device. When the power supply 11 is provided in an external device, for example, the external device and the disc grinder 1 are connected via wires, and when switch 6 is turned ON, power from the power supply 11 is supplied to the motor 10 via the wires, driving the motor 10 and rotating the polishing disc 2.

[0022] The present invention is not limited to the above example for the circuit for driving the motor 10. Various circuits can be applied to the disc grinder of the present invention as the circuit for driving the motor 10, such as one in which the polishing disc 2 is rotated when the switch 6 is turned on and the polishing disc 2 is stopped when the switch 6 is turned off.

[0023] The disc guard 7 comprises an upper guard portion 20 and an outer guard portion 21. The upper guard portion 20 has an arc shape in plan view, and the outer guard portion 21 extends downward from the outer circumference of the upper guard portion 20. The above "plan view" means "a view of the disc grinder 1 in the vertical direction of the polishing disc 2."

[0024] The disc guard 7 is attached to the outer circumference of the grinder body 3 such that the upper guard portion 20 is located above the rear region 2b of the grinding disc 2, and the outer guard portion 21 is located radially outside the rear region 2b of the grinding disc 2. The front region 2c of the grinding disc 2 is exposed and not covered by the disc guard 7. The operator performs the workpiece polishing or grinding by rotating the grinding disc 2 and pressing the front region 2c of the grinding disc 2 against the workpiece. The attachment of the inner circumference of the upper guard portion 20 to the outer circumference of the grinder body 3 can be achieved, for example, by providing a protruding plate that projects radially outward from the outer circumference of the grinder body 3, and bonding, welding, or fastening the inner circumference of the upper guard portion 20 to the protruding plate. However, the present invention is not limited to the above method for attaching the inner circumference of the upper guard portion 20 to the outer circumference of the grinder body 3. In the disc grinder of the present invention, various methods can be applied to attach the inner circumference of the upper guard portion 20 to the outer circumference of the grinder body 3 such that the upper guard portion 20 is located above the rear region 2b of the grinding disc 2, and the outer guard portion 21 is located radially outside the rear region 2b of the grinding disc 2.

[0025] The guard mechanism 8 is provided to prevent the worker from coming into contact with the polishing disc 2. The guard mechanism 8 comprises a pair of supported members 30, 30, a first connecting member 31, and a second connecting member 32, and is positioned above the polishing disc 2.

[0026] The pair of supported members 30, 30 each extend in the front-to-back direction and are spaced apart in the left-to-right direction. The first connecting member 31 extends in the left-to-right direction and connects the front ends of the pair of supported members 30, 30. The second connecting member 32 extends in the left-to-right direction and connects the middle portions of the pair of supported members 30, 30. The guard mechanism 8 is supported by the upper guard portion 20 such that, in a plan view, at least the first connecting member 31 is located radially outward of the front area of ​​the polishing disc 2. In this application, "extending in the front-to-back direction" means "the width in the front-to-back direction is longer than the width in the left-to-right direction," and "extending in the left-to-right direction" means "the width in the left-to-right direction is longer than the width in the front-to-back direction." In the illustrated example, the pair of supported members 30, 30 extend in parallel, but the pair of supported members 30, 30 do not have to extend in parallel (for example, the pair of supported members 30, 30 may be inclined to move closer together as they are on the front or rear side). Also, in the illustrated example, the first connecting member 31 and the second connecting member 32 each have an arc shape that is convex radially outward, but the shape of the first connecting member 31 and the second connecting member 32 is not particularly limited, and the first connecting member 31 and the second connecting member 32 may be linear, wavy, or have an arc shape that is convex radially inward.

[0027] The components constituting the guard mechanism 8 (a pair of supported members 30, 30, a first connecting member 31, and a second connecting member 32) are formed from metals such as aluminum and general steel, or from hard resins.

[0028] According to the disc grinder 1 of the above-described embodiment, the first connecting member 31 is located radially outward of the polishing disc 2, thereby preventing the operator from coming into contact with the polishing disc 2 (that is, the operator's body comes into contact with the first connecting member 31 before coming into contact with the polishing disc 2, thereby preventing the operator's body from coming into contact with the polishing disc 2).

[0029] Furthermore, the second connecting member 32 connects the intermediate portions of the pair of supported members 30, 30, thereby suppressing deformation of the guard mechanism 8 due to contact with the workpiece or the like. This ensures that the function of the guard mechanism 8 in preventing contact with the polishing disc 2 is stably maintained.

[0030] Preferably, the pair of supported members 30, 30 are supported by the upper guard portion 20 so that the front-rear position of the first connecting member 31 can be changed. In this case, by changing the position of the first connecting member 31 in accordance with the reduction in diameter of the polishing disc 2 due to polishing or grinding of the workpiece, the position of the first connecting member 31 can always be adjusted to a position that prevents the worker from coming into contact with the polishing disc 2.

[0031] In the illustrated example of the disc grinder 1, in order to change the front-rear position of the first connecting member 31, the disc guard includes a first support mechanism 40 for supporting one supported member 30 and a second support mechanism 41 for supporting the other supported member 30. The first support mechanism 40 and the second support mechanism 41 each include a through member 42 and a bolt 43. The through member 42 is fixed to the surface of the upper guard portion 20 and has a cavity extending in the front-rear direction. The bolt 43 can be screwed into a through hole formed in the wall of the through member 42.

[0032] In the illustrated example of the disc grinder 1, in each of the first support mechanism 40 and the second support mechanism 41, with the supported member 30 inserted into the cavity, a bolt 43 is screwed into the through hole, and the tip of the bolt 43 extending into the cavity presses against the supported member 30, thereby supporting the pair of supported members 30, 30 on the upper guard portion 20. Furthermore, in each of the first support mechanism 40 and the second support mechanism 41, the position of the guard mechanism 8 in the front-rear direction can be changed by loosening the screwing of the bolt 43 into the through hole and releasing the pressure on the supported member 30 by the tip of the bolt 43.

[0033] Furthermore, from the viewpoint of suppressing deformation of the supported member 30 due to the pressure of the tip of the bolt 43, it is preferable to cover at least the portion of the supported member 30 that is inserted into the cavity of the inserted member 42 with a cylindrical body 50 made of an elastic material such as rubber or resin. In this case, by pressing the tip of the bolt 43 that extends into the cavity against the cylindrical body 50, the pressing force from the tip of the bolt 43 is applied to the supported member 30 via the cylindrical body 50, so that the pair of supported members 30, 30 are supported by the upper guard portion 20.

[0034] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Forms obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention.

[0035] For example, the position of the first connecting member 31 in the front-to-back direction may be changed by constructing the pair of supported members 30, 30 with members that can be extended and retracted in the front-to-back direction.

[0036] Furthermore, the second connecting member 32 is not necessarily required and does not have to be provided on the guard mechanism 8.

[0037] Furthermore, the member supporting the pair of supported members 30, 30 is not limited to the upper guard portion 20, but can be any various member provided on the disc grinder 1. Even when the pair of supported members 30, 30 are supported by a member other than the upper guard portion 20, in a plan view, at least the first connecting member 31 of the guard mechanism 8 can be positioned radially outward from the polishing disc 2 to prevent the operator from coming into contact with the polishing disc 2.

[0038] Furthermore, the disc guard 7 is not necessarily required and may be omitted. In this case, the disc grinder of the present invention is such that, for example, not only the front region but also the rear region of the polishing disc 2 can be pressed against the workpiece, and in order to prevent the operator from coming into contact with any position on the polishing disc 2, the guard mechanism 8 is provided on the disc grinder such that at least the first connecting member 31 of the guard mechanism 8 is located radially outward from any position on the polishing disc 2.

[0039] Furthermore, in the above embodiment, an example was shown in which the guard mechanism 8 is provided above the polishing disc 2, assuming that the workpiece is polished or ground by pressing the lower side of the polishing disc 2 against the workpiece. However, if the normal way of using the disc grinder 1 is to polish or grind the workpiece by pressing the upper side of the polishing disc 2 against the workpiece, the guard mechanism 8 may be provided below the polishing disc 2.

[0040] Furthermore, the means by which the worker grips the object are not limited to the main grip 4 and sub-grip 5 shown in the above embodiment. For example, a single grip may be provided as the means by which the worker grips the object. In this case, for example, a switch 6 for switching the power supply to the motor 10 may be provided on the single grip. [Explanation of symbols]

[0041] 1. Angle grinder 10 motors 2 polishing discs 2b Rear area of ​​the polishing disc 2c Front area of ​​the polishing disc 3. Grinder body 7 Disc Guard 8 Guard mechanism 20 Upper guard section 21 Outer guard section 30 Supported member 31 First connecting member 32 Second connecting member 40 First support mechanism 41 Second support mechanism 42 Inserted member 43 volts

Claims

1. A disc grinder that polishes or grinds a workpiece by pressing a rotating abrasive disc against the workpiece, It is equipped with a guard mechanism to prevent the worker from coming into contact with the polishing disc, The guard mechanism comprises a pair of supported members and a first connecting member, The pair of supported members each extend in the front-to-back direction and are arranged with a gap between them in the left-to-right direction. The first connecting member extends in the left-right direction and connects the front ends of the pair of supported members. In the guard mechanism, at least the first connecting member is located radially outward (hereinafter referred to as radially outward) of the polishing disc in a plan view.

2. The disc grinder according to claim 1, wherein the guard mechanism comprises a second connecting member that extends in the left-right direction and connects the intermediate portions of the pair of supported members.

3. The grinder body and Equipped with a disc guard, The grinder body has a built-in motor for rotating the grinding disc. The polishing disc is rotatably suspended from the grinder body, The disc guard comprises an upper guard portion that is arc-shaped in plan view and an outer guard portion that extends downward from the outer circumference of the upper guard portion. The inner circumference of the upper guard portion is attached to the outer circumference of the grinder body such that the upper guard portion is located above the rear region of the polishing disc and the outer guard portion is located radially outside the rear region of the polishing disc, so that the front region of the polishing disc is exposed and not covered by the disc guard. The disc grinder according to item 1, wherein the pair of supported members are supported by the upper guard portion such that at least the first connecting member is located radially outward of the front region of the polishing disc in the guard mechanism.

4. The disc grinder according to claim 3, wherein the pair of supported members are supported by the upper guard portion so that the front-rear position of the first connecting member can be changed.

5. The disc guard comprises a first support mechanism for supporting one of the supported members and a second support mechanism for supporting the other supported member. The first support mechanism and the second support mechanism each comprise a member to be inserted and a bolt, The inserted member is fixed to the surface of the upper guard portion and has a cavity extending in the front-rear direction. The bolt is screwable into the through hole formed in the member to be inserted. In each of the first and second support mechanisms, with the supported member inserted into the cavity, the bolt is screwed into the through hole, and the tip of the bolt extending into the cavity presses against the supported member, thereby supporting the pair of supported members on the upper guard portion. The disc grinder according to claim 4, wherein in each of the first support mechanism and the second support mechanism, the front-rear position of the first connecting member can be changed by loosening the screwing of the bolt into the through hole and releasing the pressure of the tip of the bolt on the supported member.

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