WO2021140617A1

WO2021140617A1 - Electric tool

Info

Publication number: WO2021140617A1
Application number: PCT/JP2020/000471
Authority: WO
Inventors: 麦平田中
Original assignee: 三菱電機ビルテクノサービス株式会社
Priority date: 2020-01-09
Filing date: 2020-01-09
Publication date: 2021-07-15
Also published as: CN114901446A; JPWO2021140617A1

Abstract

An electric tool (1) is provided with a body (2), a battery (3), a bit (4) made of metal, a drive unit (11), a ground wire (6), a detection unit (12), and a cutoff unit (13). The drive unit (11) oscillates the bit (4) when electric power is supplied thereto from the battery (3). The detection unit (12) detects that the bit (4) is grounded. The cutoff unit (13) cuts off electric power supplied from the battery (3) to the drive unit (11) when the detection unit (12) detects that the bit (4) is grounded.

Description

Electric tool

The present invention relates to a power tool.

For example, in elevator repair work, power tools are used to scrape concrete. Inside the concrete, a metal pipe is buried to protect the electric wire. As another example, the inside of concrete is filled with reinforcing bars. Workers performing repair work do not know the exact position of metal members such as metal pipes. When the bit of the power tool comes into contact with the metal member, the bit is damaged or the metal member is damaged.

Patent Document 1 describes a cord reel. For example, a power tool is connected to the cord reel described in Patent Document 1. When the bit of the power tool connected to the cord reel comes into contact with the metal member inside the concrete, the power supply to the power tool is cut off.

Japan Utility Model Registration No. 3219613

In elevator repair work, power tools are used at various heights to scrape concrete. For example, a worker rides on an elevator car and scrapes concrete. When performing such an operation using the cord reel described in Patent Document 1, the operator must carry the cord reel onto the car together with the electric tool. In addition, the worker must perform the work of shaving the concrete with the cord reel placed on the basket. For this reason, there is a problem that the cord reel interferes with the work and the workability is poor. Such a problem can occur not only in elevator repair work but also in other works as well.

This invention was made to solve the above-mentioned problems. An object of the present invention is to provide a power tool capable of efficiently performing work and detecting that a bit has come into contact with a metal member.

The electric tool according to the present invention has a main body, a battery supported by the main body, a metal bit supported by the main body and extending in the first direction from the main body, and power is supplied from the battery in the first direction. A driving means for vibrating the bit along the line, a connecting means having a ground terminal electrically connected to the bit, a detecting means for detecting that the bit is grounded, and a detecting means for detecting that the bit is grounded. When detected by, a shutoff means for shutting off the power supply from the battery to the drive means is provided.

The power tool according to the present invention has a main body, a plug with a ground terminal, a power cord extending from the main body, a metal bit supported by the main body and extending in the first direction from the main body, and a plug connected to the main body. When power is supplied from the power supply, the driving means for vibrating the bit along the first direction, the detecting means for detecting that the bit is grounded, and the detecting means for detecting that the bit is grounded are detected. , A shutoff means for shutting off the power supply from the power supply to the drive means.

With the power tool according to the present invention, it is possible to detect that the bit has come into contact with a metal member, and further, the work can be performed efficiently.

It is a figure which shows the example of the power tool in Embodiment 1. FIG. It is a figure for demonstrating the function which a power tool has. It is a figure which shows typically the example which uses the electric tool in the repair work of an elevator. It is a flowchart which shows the operation example of the power tool in Embodiment 1. It is a figure which shows another example of the power tool in Embodiment 1. FIG.

The present invention will be described with reference to the accompanying drawings. Overlapping description will be simplified or omitted as appropriate. In each figure, the same reference numerals indicate the same parts or corresponding parts.

Embodiment 1.
FIG. 1 is a diagram showing an example of a power tool 1 according to the first embodiment. FIG. 2 is a diagram for explaining the function of the power tool 1. The power tool 1 is used for scraping concrete, for example, in an elevator repair work. In the example shown in this embodiment, the power tool 1 includes a main body 2, a battery 3, a bit 4, a lamp 5, and a ground wire 6.

The main body 2 is provided with a handle 8 for the person using the power tool 1 to grasp. The main body 2 includes a switch 9 for a person who grips the handle 8 to operate the main body 2. FIG. 1 shows an example in which the main body 2 includes a button-type switch 9. Further, the main body 2 includes a drive unit 11, a detection unit 12, a blocking unit 13, and a lighting unit 14.

The battery 3 is supported by the main body 2. The battery 3 may be detachable from the main body 2. The electric power required for the power tool 1 is supplied from the battery 3.

Bit 4 is a metal rod-shaped member for actually shaving concrete. For example, the bit 4 is a metal concrete drill bit. The bit 4 is supported by the main body 2 so as to extend from the main body 2 in a specific direction. In the following, the direction in which the bit 4 extends from the main body 2 is also referred to as the A direction. The bit 4 is supported by the main body 2 so as to be displaceable along the A direction. Further, the bit 4 may be supported by the main body 2 so as to be rotatable around the A direction.

The lamp 5 is provided on the main body 2. The lamp 5 is arranged at a position visible to the person holding the handle 8.

The ground wire 6 is an example of means for being connected to a member that is grounded. In the following, the grounded member is also referred to as a grounded member. The ground wire 6 extends from the main body 2. The ground wire 6 has a ground terminal 6a at its tip. The ground terminal 6a is electrically connected to the bit 4.

The drive unit 11 drives the bit 4 by being supplied with electric power from the battery 3. For example, when power is supplied from the battery 3, the drive unit 11 vibrates the bit 4 along the A direction. Further, the drive unit 11 rotates the bit 4 around the A direction when power is supplied from the battery 3. When a specific operation is performed on the switch 9, the electric power from the battery 3 is supplied to the drive unit 11. For example, if the main body 2 includes a button-type switch 9, the bit 4 vibrates and rotates when the switch 9 is pressed.

The detection unit 12 detects that the bit 4 has been grounded. Inside the main body 2, the bit 4 is electrically connected to the battery 3. The ground terminal 6a is electrically connected to the battery 3. When a specific operation is performed on the switch 9, a potential difference is generated between the bit 4 and the ground terminal 6a according to the output voltage of the battery 3. For example, the detection unit 12 detects that the bit 4 is grounded when the resistance value between the bit 4 and the ground terminal 6a is smaller than the reference value.

The cutoff unit 13 cuts off the power supply to the drive unit 11 when a specific condition is satisfied. The lighting unit 14 controls the lighting and extinguishing of the lamp 5. Hereinafter, the function of the power tool 1 will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is a diagram schematically showing an example in which the power tool 1 is used in the repair work of the elevator. FIG. 4 is a flowchart showing an operation example of the power tool 1 according to the first embodiment.

For example, when the power tool 1 is used in the repair work of the elevator, the worker moves the power tool 1 onto the car 21 with the power tool 1. When the operator moves onto the car 21, first, the ground terminal 6a of the ground wire 6 is connected to the grounded member in the hoistway 22.

When installing the elevator, the sill 23 of the landing is accurately positioned and then welded and fixed to the reinforcing bar 24. FIG. 3 shows an example in which the sill 23 is welded and fixed to the reinforcing bar 24 via the reinforcing brace 25. The threshold 23 and the brace 25 are made of metal. The threshold 23 and the brace 25 are examples of grounded members arranged in the hoistway 22.

The worker may connect the ground terminal 6a to the threshold 23 before performing the chipping work with the power tool 1 on the car 21 in the repair work of the elevator. The threshold 23 is provided at each landing. The operator may connect the ground terminal 6a to the threshold 23 arranged at the height closest to the work place. FIG. 3 shows an example in which the ground wire 6 is connected to the sill 23 by sandwiching the sill 23 with the ground terminal 6a. In the example shown in FIG. 3, the operator can easily attach the ground terminal 6a to the grounded member even from above the car 21.

In the elevator repair work, the threshold 23 may be replaced. Even if the threshold 23 is removed, the reinforcing bars 24 or braces 25 to which the threshold 23 is fixed are left in the hoistway 22. If the sill 23 has already been removed, the operator may connect the ground terminal 6a to the reinforcing bar 24 or the brace 25 before performing the chipping work with the power tool 1.

In the power tool 1, it is determined whether or not the switch 9 is pressed (S101). When the ground terminal 6a is connected to the threshold 23, the operator puts the bit 4 on the concrete wall and pushes the switch 9 with the hand holding the handle 8. As a result, S101 determines Yes. If it is determined to be Yes in S101, power is supplied from the battery 3 to the drive unit 11. As a result, the drive unit 11 drives the bit 4 (S102). In the example shown in this embodiment, in S102, the bit 4 vibrates along the A direction and rotates about the A direction.

In the power tool 1, if it is determined to be Yes in S101, the detection unit 12 determines whether or not the bit 4 is grounded (S103). FIG. 3 shows an example in which a metal pipe 26 for protecting an electric wire is buried inside concrete. The metal tube 26 is grounded. Further, as described above, the ground terminal 6a is connected to the grounded member. Therefore, when the bit 4 comes into contact with the metal tube 26 during the chipping operation, the detection unit 12 detects that the bit 4 is grounded (Yes in S103).

When the detection unit 12 detects that the bit 4 is grounded, the cutoff unit 13 cuts off the power supply from the battery 3 to the drive unit 11 (S104). Therefore, when the bit 4 comes into contact with the metal tube 26 during the chipping operation, the vibration and rotation of the bit 4 are immediately stopped. This makes it possible to prevent the metal tube 26 from being damaged and the bit 4 from being damaged.

Further, when the detection unit 12 detects that the bit 4 is grounded, the lighting unit 14 lights the lamp 5 (S105). By looking at the lit lamp 5, the operator can know that the bit 4 has come into contact with a metal member such as the metal tube 26. The lamp 5 is an example of a notification device provided in the main body 2. The lighting unit 14 is an example of a notification unit that controls the notification device. The lighting unit 14 lighting the lamp 5 is an example of the notification unit operating the alarm. For example, the main body 2 may be provided with a buzzer as a notification device. In such a case, the notification unit sounds the buzzer in S105. As another example, the main body 2 may be provided with both a lamp 5 and a buzzer as an alarm. In such a case, the notification unit turns on the lamp 5 and sounds the buzzer in S105.

In the example shown in the present embodiment, the power tool 1 can detect that the bit 4 comes into contact with a metal member such as a metal tube 26 during the chipping operation. Therefore, the operator does not need to carry the cord reel with the metal sensor onto the car 21 when performing the chipping work on the car 21. The operator does not need to perform the chipping work with the cord reel placed on the car 21, and the work can be performed efficiently.

The other functions that can be adopted by the power tool 1 will be described below. The power tool 1 may be adopted by combining a plurality of functions shown below.

In the above explanation, an example in which various functions are realized based on the direct current from the battery 3 is shown. As another example, the main body 2 of the power tool 1 may further include a conversion unit 15 as shown in FIG. The conversion unit 15 converts the direct current from the battery 3 into alternating current. In such a case, the alternating current from the conversion unit 15 is supplied to the drive unit 11. Further, the bit 4 is electrically connected to the conversion unit 15. The ground terminal 6a is electrically connected to the conversion unit 15. When a specific operation is performed on the switch 9, a potential difference is generated between the bit 4 and the ground terminal 6a according to the output voltage of the conversion unit 15.

As another example, the power tool 1 does not have to be equipped with the battery 3. FIG. 5 is a diagram showing another example of the power tool 1 according to the first embodiment. In the example shown in FIG. 5, the power tool 1 includes a main body 2, a bit 4, a lamp 5, and a power cord 7. The power cord 7 extends from the main body 2. The power cord 7 has a plug 7a with a ground terminal. The ground terminal of the plug 7a is electrically connected to the bit 4. The main body 2 includes a handle 8 and a switch 9. Further, the main body 2 includes a drive unit 11, a detection unit 12, a blocking unit 13, and a lighting unit 14.

A grounded outlet 27 is often provided on the car 21 for maintenance personnel who maintain the elevator. When the power tool 1 shown in FIG. 5 is used on the car 21 in the repair work of the elevator, the operator may connect the plug 7a to the outlet 27 before starting the chipping work. The electric power required for the power tool 1 is supplied from a commercial power source via a plug 7a connected to the outlet 27. By connecting the plug 7a to the outlet 27, the above-mentioned function of the battery 3 and the function of the ground wire 6 can be realized at the same time.

The drive unit 11 drives the bit 4 by supplying electric power from a commercial power source to which the plug 7a is connected. For example, when power is supplied from the commercial power source, the drive unit 11 vibrates the bit 4 along the A direction and rotates the bit 4 around the A direction. The electric power from the commercial power source is supplied to the drive unit 11 by performing a specific operation on the switch 9.

The detection unit 12 detects that the bit 4 is grounded, for example, when the resistance value between the ground terminal of the bit 4 and the plug 7a is smaller than the reference value. Therefore, when the bit 4 comes into contact with the metal tube 26 during the chipping operation, the detection unit 12 detects that the bit 4 is grounded. When the detection unit 12 detects that the bit 4 is grounded, the cutoff unit 13 cuts off the power supply from the commercial power supply to which the plug 7a is connected to the drive unit 11. Therefore, when the bit 4 comes into contact with the metal tube 26 during the chipping operation, the vibration and rotation of the bit 4 are immediately stopped. This makes it possible to prevent the metal tube 26 from being damaged and the bit 4 from being damaged.

Further, when the detection unit 12 detects that the bit 4 is grounded, the lighting unit 14 lights the lamp 5. At this time, the buzzer provided on the main body 2 may sound. By looking at the lit lamp 5, the operator can know that the bit 4 has come into contact with a metal member such as the metal tube 26.

In the elevator repair work, the outlet 27 may be removed from the top of the car 21. In preparation for such a case, the power tool 1 preferably includes a battery 3 and a ground wire 6. The power tool 1 may include both a power cord 7, a battery 3, and a ground wire 6.

In the present embodiment, each part indicated by reference numerals 11 to 15 indicates a function possessed by the main body 2 of the power tool 1. The function of the main body 2 is realized by, for example, dedicated hardware. Some of the functions of the main body 2 may be realized by software. In such a case, the main body 2 includes a processing circuit including a processor and a memory as hardware resources. The main body 2 realizes the above-mentioned part of the function by executing the program stored in the memory by the processor.

The present invention can be applied to a power tool in which a bit can unintentionally come into contact with a metal member while the bit is being driven.

1 power tool, 2 main body, 3 battery, 4 bits, 5 lamp, 6 ground wire, 6a ground terminal, 7 power cord, 7a plug, 8 handle, 9 switch, 11 drive unit, 12 detector, 13 cutoff unit, 14 Lighting part, 15 conversion part, 21 basket, 22 hoistway, 23 threshold, 24 rebar, 25 brace, 26 metal pipe, 27 outlet

Claims

With the main body
The battery supported by the main body and
A metal bit supported by the main body and extending in the first direction from the main body,
A driving means that vibrates the bit along the first direction by being supplied with electric power from the battery.
A connecting means having a ground terminal electrically connected to the bit,
A detection means for detecting that the bit has been grounded, and
When the detecting means detects that the bit is grounded, the cutting means for cutting off the power supply from the battery to the driving means, and
Power tool with.
Further provided with a conversion means for converting direct current from the battery into alternating current,
The bit is electrically connected to the conversion means and
The power tool according to claim 1, wherein the ground terminal is electrically connected to the conversion means.
With the main body
A power cord that has a plug with a ground terminal and extends from the main body,
A metal bit supported by the main body and extending in the first direction from the main body,
A driving means that vibrates the bit along the first direction by supplying electric power from a power source to which the plug is connected.
A detection means for detecting that the bit has been grounded, and
When the detecting means detects that the bit is grounded, the cutting means for cutting off the power supply from the power source to the driving means, and
Power tool with.
The alarm provided in the main body and
When the detection means detects that the bit has been grounded, the notification means for operating the notification means and
The power tool according to any one of claims 1 to 3, further comprising.
Any one of claims 1 to 4, wherein the drive means vibrates the bit along the first direction and rotates the bit around the first direction when electric power is supplied. Power tools described in the section.