Disc grinder

Abstract

Reduces the risk of the rotating tip tool coming into contact with an unintended object. [Solution] The disc grinder 1 comprises a grinding disc 2, a motor 8 for rotating the grinding disc 2, a main grip 3 held by the operator's right hand, a sub-grip 4 held by the operator's left hand, a main switch 5 which is pressed when the right hand is gripping the main grip 3, and a sub-switch 6 which is pressed when the left hand is gripping the sub-grip 4. The motor 8 rotates the grinding disc 2 when both the main switch 5 and the sub-switch 6 are pressed.

Description

Technical Field

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

Background Art

[0002] FIG. 5 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 grinding 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 a motor (not shown) to rotate the grinding disk 102. By pressing the rotating grinding disk 102 against a workpiece, the workpiece can be grinded or polished.

[0003] The switch 105 is a paddle switch. Therefore, when the grinding disk 102 is rotating and the operator accidentally releases the main grip 103, the switch 105 is turned off and the rotation of the grinding disk 102 stops. This reduces the risk of an accident in which the rotating grinding disk 102 contacts the operator's foot or the like.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, with conventional disc grinders 101, if the operator accidentally releases only the sub-grip 104 while the grinding disc 102 is rotating, the grinding disc 102 will not stop, and there is a risk that the rotating grinding disc 102 may come into contact with an unintended object (such as the operator's foot, an object other than the workpiece, or a part of the workpiece other than the grinding or polishing area).

[0006] The present invention has been made in view of the above problems, and aims to reduce the risk of a rotating tip tool coming into contact with an unintended object. [Means for solving the problem]

[0007] To solve the above problems, the disc grinder according to the present invention comprises a tip tool for processing a workpiece, a motor for rotating the tip tool, a first grip held by one hand of the operator, a second grip held by the other hand of the operator, a first switch that is pressed when one hand is gripping the first grip, and a second switch that is pressed when the other hand is gripping the second grip, wherein the motor rotates the tip tool when both the first switch and the second switch are pressed.

[0008] In the disc grinder according to the present invention, the first switch and the second switch are preferably paddle switches. [Effects of the Invention]

[0009] According to the present invention, the risk of a rotating tip tool coming into contact with an unintended object can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the configuration of a disc grinder according to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing an example of a circuit configuration for driving a motor. [Figure 3] This is a schematic diagram showing another example of a circuit configuration for driving a motor. [Figure 4] This is a schematic diagram showing yet another example of a circuit configuration for driving a motor. [Figure 5] This is a perspective view showing the configuration of a conventional disc grinder. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, and various modifications are possible without departing from its spirit.

[0012] (Overall structure) Figures 1(a) and (b) are perspective views showing the configuration of a disc grinder 1 according to one embodiment of the present invention. The disc grinder 1 is a handheld power tool and comprises a grinding disc 2, a motor, a main grip 3, a sub-grip 4, a main switch 5, and a sub-switch 6.

[0013] The grinding disc 2 is an end tool for processing the workpiece and is located at the tip of the disc grinder 1. The motor that rotates the grinding disc 2 is a rotational power source such as an electric or pneumatic fluid machine and is built into the body of the disc grinder 1. The operator grinds or polishes the workpiece by pressing the rotating grinding disc 2 against the workpiece.

[0014] The main grip 3 is a grip held in the operator's right hand and extends towards the front of the abrasive disc 2 from the operator's perspective. The sub-grip 4 is a grip held in the operator's left hand and extends to the left of the abrasive disc 2 from the operator's perspective. In other words, the operator uses the disc grinder 1 while holding the main grip 3 and sub-grip 4 with their right and left hands, respectively.

[0015] The main grip 3 and the sub - grip 4 respectively correspond to the first grip and the second grip described in the claims, but the main grip 3 may correspond to the second grip and the sub - grip 4 may correspond to the first grip. Also, the right hand and the left hand respectively correspond to one hand and the other hand described in the claims, but the right hand may correspond to the other hand and the left hand may correspond to one hand.

[0016] The main switch 5 is provided on the main grip 3 and is pressed when the right hand is gripping the main grip 3. In this embodiment, the main switch 5 is provided at the lower part of the main grip 3 and is pressed by the index finger of the right hand when the right hand is gripping the main grip 3.

[0017] The sub - switch 6 is provided in front of the sub - grip 4 and is pressed when the left hand is gripping the sub - grip 4. In this embodiment, the sub - switch 6 is provided at the front part of the sub - grip 4 and is pressed by at least one of the index finger, middle finger, and ring finger of the left hand when the left hand is gripping the sub - grip 4.

[0018] Both the main switch 5 and the sub - switch 6 are preferably paddle switches. That is, the main switch 5 and the sub - switch 6 are in the on state only when pressed and are always in the off state when not pressed.

[0019] Note that the position of the main switch 5 is not particularly limited as long as it can be pressed without hindering the work when the right hand is gripping the main grip 3. Similarly, the position of the sub - switch 6 is not particularly limited as long as it can be pressed without hindering the work when the left hand is gripping the sub - grip 4.

[0020] The main switch 5 and the sub - switch 6 respectively correspond to the first switch and the second switch described in the claims, but the main switch 5 may correspond to the second switch and the sub - switch 6 may correspond to the first switch.

[0021] Inside the housing above the polishing disk 2, a motor for rotating the polishing disk 2 is built in. The motor is a rotational power source by an electric motor or a pneumatic fluid machine, and rotates the polishing disk 2 when both the main switch 5 and the sub-switch 6 are pressed. That is, when at least either the main switch 5 or the sub-switch 6 is turned off, the motor stops the rotation of the polishing disk 2. Therefore, not only when the operator releases both hands from the main switch 5 and the sub-switch 6, but also when the operator releases only the main switch 5 and when the operator releases only the sub-switch 6, the polishing disk 2 stops.

[0022] In the conventional disk grinder 101 shown in FIG. 5, since no switch is provided on the sub-grip 104, there is a problem that the polishing disk 102 does not stop when the operator releases only the sub-grip 104. On the other hand, in the disk grinder 1 according to the present embodiment, even when the operator releases only the sub-switch 6, the sub-switch 6 is turned off, so that the polishing disk 2 can be stopped. Therefore, the risk that the rotating polishing disk 2 contacts an object unintended by the operator or the like can be reduced.

[0023] (Circuit configuration) FIG. 2 is a schematic diagram showing an example of a circuit configuration for driving a motor. In FIG. 2, the motor 8 is a universal motor and is supplied with electric power from the power source 7.

[0024] The main switch 5 and the sub-switch 6 are provided between the power source 7 and the motor 8. Thereby, when at least either the main switch 5 or the sub-switch 6 is turned off, power is not supplied to the motor 8, so that the polishing disk 2 stops.

[0025] Figure 3 is a schematic diagram showing another example of a circuit configuration for driving a motor. In Figure 3, the motor 8 is an inverter-controlled synchronous motor or dielectric motor, and the power supply is controlled by an inverter circuit 9 located between the power supply 7 and the motor 8.

[0026] The main switch 5 and the sub-switch 6 are located between the inverter circuit 9 and the motor 8. As a result, when at least one of the main switch 5 or the sub-switch 6 is turned off, power is no longer supplied to the motor 8, and the polishing disc 2 stops.

[0027] The main switch 5 and sub-switch 6 may be provided between the power supply 7 and the inverter circuit 9. Alternatively, one of the main switch 5 and sub-switch 6 may be provided between the power supply 7 and the inverter circuit 9, and the other between the inverter circuit 9 and the motor 8.

[0028] Figure 4 is a schematic diagram showing yet another example of a circuit configuration for driving a motor. In Figure 4, the motor 8 is an inverter-controlled synchronous motor or dielectric motor, and the power supply is controlled by an inverter circuit 9 located between the power supply 7 and the motor 8. The inverter circuit 9 is controlled by a controller 10.

[0029] The main switch 5 and sub-switch 6 are located on the input signal lines for inputting operation / stop signals to the controller 10. As a result, when at least one of the main switch 5 or sub-switch 6 is turned off, the inverter circuit 9 stops and power is no longer supplied to the motor 8, causing the polishing disc 2 to stop.

[0030] (Summary) As described above, the disc grinder 1 according to this embodiment is equipped with two switches, a main switch 5 and a sub-switch 6, and is configured to rotate the grinding disc 2 when both the main switch 5 and the sub-switch 6 are pressed. As a result, if the operator releases either the main grip 3 or the sub-grip 4, at least one of the main switch 5 and the sub-switch 6 will turn off, and the rotation of the grinding disc 2 will stop. Therefore, compared to conventional disc grinders, the risk of the rotating grinding disc 2 coming into contact with unintended objects such as the operator can be reduced.

[0031] (Additional notes) 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.

[0032] In the above embodiment, both the main switch 5 and the sub-switch 6 are paddle switches, but they are not particularly limited as long as they are turned on only when the operator is gripping the main grip 3 and the sub-grip 4, respectively. For example, the main switch 5 and the sub-switch 6 can also be made up of pressure sensors or the like.

[0033] Furthermore, while the disc grinder 1 according to the above embodiment is equipped with a grinding disc 2 for cutting or polishing a workpiece as an end tool, the end tool is not limited to this. For example, the disc grinder 1 may be equipped with an industrial grinding wheel for cutting a workpiece as an end tool. [Explanation of symbols]

[0034] 1. Angle grinder 2. Polishing disc (tip tool) 3. Main grip (first grip) 4. Sub-grip (second grip) 5. Main switch (first switch) 6. Sub-switch (second switch) 7 Power supply 8 motors 9. Inverter Circuit 10 Controllers

Claims

1. Advanced tools for machining workpieces, A motor for rotating the aforementioned tip tool, A first grip held in one hand of the worker, A second grip held in the other hand of the aforementioned worker, A first switch that is pressed when one of the hands is gripping the first grip, A second switch that is pressed when the other hand is gripping the second grip, Equipped with, The disc grinder is characterized in that the motor rotates the tip tool when both the first switch and the second switch are pressed.

2. The disc grinder according to claim 1, characterized in that the first switch and the second switch are paddle switches.

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