JP7261698B2 - Portable machine tool - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable machine tool, and more particularly to a portable machine tool in which machining is performed while a machine tool body is fixed to a workpiece by an electromagnet.

2. Description of the Related Art Among machine tools such as drilling machines, there are portable machine tools that can be carried to a work site to perform machining work on a workpiece. As such a portable machine tool, an electric motor for driving a machining tool such as a drill or an annular cutter, an electromagnet for fixing the machine tool main body to the workpiece, and an electric motor and an electromagnet are controlled. and a control unit for controlling the driving of the electric motor and the operation of the electromagnet by operating a plurality of switches provided on the machine tool body. (Patent document 1)

JP 2014-231129 A

When there are multiple switches for operating electric motors, electromagnets, etc., and they are placed relatively close to each other, it is possible to accidentally operate another switch when trying to operate something. can be. For example, when an electromagnet switch is pressed to activate an electromagnet, if a motor drive switch for driving the electric motor is also pressed by mistake, it is dangerous if the electric motor is unintentionally driven.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a portable machine tool capable of preventing an electric motor from being unintentionally started due to an erroneous operation of a switch.

That is, the present invention
A portable machine tool,
machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a controller configured to control driving of the electromagnet and the electric motor;
an electromagnet switch connected to the controller for manipulating actuation of the electromagnet;
a motor stop switch connected to the control unit for stopping driving of the electric motor;
a motor drive switch connected to the controller for starting to drive the electric motor;
with
The control unit drives the electric motor when the motor drive switch is operated while at least one of the electromagnet switch and the motor stop switch is operated by the user of the portable machine tool. To provide a portable machine tool which is prevented from starting

In the portable machine tool, when the motor drive switch is operated while at least one of the electromagnet switch and the motor stop switch is operated by the user, the electric motor does not start to drive. there is This makes it possible to prevent the electric motor from being unintentionally driven when the motor drive switch is erroneously operated when another switch is operated.

again,
When the controller determines that the motor drive switch and the electromagnet switch are operated at the same time, it starts or stops the operation of the electromagnet without starting the drive of the electric motor, and controls the motor drive switch and the motor. When it is determined that the stop switch is operated at the same time, the electric motor can be stopped without starting the driving of the electric motor.

Specifically, the electromagnet switch, the motor stop switch, and the motor drive switch may be momentary switches that are ON only when they are operated.

again,
the motor drive switch and the motor stop switch are composed of one motor switch,
The controller starts driving the electric motor when the motor switch is operated to start driving the electric motor while the electromagnet switch is being operated by the user of the portable machine tool. You can also choose not to.

An embodiment of a portable machine tool according to the present invention will be described below with reference to the accompanying drawings.

1 is a side view of a portable machine tool according to an embodiment of the present invention; FIG. FIG. 2 is a sectional view of the portable machine tool of FIG. 1; FIG. 2 is a functional block diagram of the portable machine tool of FIG. 1;

A portable machine tool 1 according to one embodiment of the present invention includes a machine tool main body 10 and an electromagnet 12 attached to the lower side of the machine tool main body 10, as shown in FIG. A battery 14 serving as a main power source for the portable machine tool 1 is detachably attached to the rear of the machine tool body 10 . As shown in FIG. 2, the machine tool main body 10 includes a working tool mounting portion 18 to which an annular cutter 16 (working tool) is detachably mounted. An electric motor 20 is provided for this purpose. The machining tool mounting portion 18 and the electric motor 20 are drivingly connected via a gear mechanism 22 comprising a plurality of gears. As shown in FIG. 1 , a lever 24 is attached to the machine tool body 10 , and by pivoting the lever 24 , the machining tool attachment portion 18 is moved up and down together with the annular cutter 16 . As shown in FIG. 2, the electromagnet 12 has a ring-shaped first coil 26 and a ring-shaped second coil 30 as well. When power is supplied from the battery 14 to the first coil 26 and the second coil 30 while the portable machine tool 1 is placed on a magnetic material, the machine tool main body is moved by the magnetic attraction force generated by the electromagnet 12. 10 is fixed with respect to the workpiece, which is a magnetic material. The portable machine tool 1 presses an annular cutter 16 rotationally driven by an electric motor 20 against the workpiece while the machine tool main body 10 is fixed to the workpiece by the electromagnet 12 . It is a drilling machine designed to perform processing operations on objects.

As shown in FIG. 1, a motor drive switch 34 for starting driving the electric motor 20, a motor stop switch 36 for stopping driving the electric motor 20, and an electromagnet 12 are provided on the side of the machine tool body 10. An electromagnet switch 38 is provided for starting and stopping the operation of the. A lighting switch 40 is also arranged on the side surface of the machine tool main body 10 . The lighting switch 40 is used to turn on and off a lighting device (not shown) arranged on the lower front surface of the machine tool body 10 . These switches 34, 36, 38, and 40 are all momentary switches that are ON only while being pressed and return OFF when released. The machine tool main body 10 is further provided with an LED display section 41 for indicating the state of the portable machine tool 1 to the user.

As shown in FIG. 2, a magnetic sensor 42 is attached to the electromagnet 12 . The magnetic sensor 42 is adapted to measure the magnitude of magnetic flux density in the magnetic circuit of the electromagnet 12 formed around the electromagnet 12 through the workpiece.

The portable machine tool 1 has a control circuit board 46 in the machine tool main body 10, and the control circuit board 46 is provided with a control section 48 (FIG. 3) for controlling the electric motor 20, the electromagnet 12, and the like. ing. When the battery 14 is attached to the machine tool main body 10, power is supplied from the battery 14 to the control unit 48 through the control power supply circuit 50, and the control unit 48 is activated. The control unit 48 controls driving of the electric motor 20 according to the operating states of the motor drive switch 34 and the motor stop switch 36 . Basically, when the motor drive switch 34 is pushed and turned on, the electric motor 20 starts to be driven, and when the motor stop switch 36 is pushed and turned on, the electric motor 20 is stopped. The control unit 48 controls the rotation speed of the electric motor 20 by transmitting control signals to the motor control unit 52 . The control unit 48 also monitors the load condition of the electric motor 20 by detecting the amount of current flowing through the electric motor 20 with the motor current detection unit 54 . The control unit 48 starts operating the electromagnet 12 when the electromagnet switch 38 is pressed to turn it on while the electromagnet 12 is not operating, and turns the electromagnet switch 38 to be turned on while the electromagnet 12 is operating. When the state is reached, the operation of the electromagnet 12 is stopped. The control unit 48 controls power supplied to the first coil 26 and the second coil 30 via the coil control circuit 56 . Since the first coil 26 and the second coil 30 are connected in series, the power supplied to the first coil 26 and the second coil 30 will generally be the same. The coil disconnection detection circuit 58 detects currents flowing through the first coil 26 and the second coil 30 to detect disconnection of the first coil 26 and the second coil 30 . When the disconnection of the first coil 26 or the second coil 30 is detected, the control unit 48 stops the control and turns on the LED display unit 41 to inform the user that the coils 26, 30 are disconnected. Further, the control unit 48 stores that the coils 26 and 30 are disconnected, and lights the LED display unit 41 when the battery 14 is once disconnected and reconnected and the control of the control unit 48 is resumed. It also informs the user that the coils 26, 30 are disconnected.

The control circuit board 46 is further provided with a power supply voltage detection circuit 60 for detecting the voltage (power supply voltage) of the battery 14 connected to the machine tool body 10 .

In the portable machine tool 1, the electric motor 20 is driven and the electromagnet 12 is operated by operating the motor drive switch 34, the motor stop switch 36, and the electromagnet switch 38, which are connected to the control section 48, as described above. is controlled. However, when the motor drive switch 34 is operated while at least one of the electromagnet switch 38 and the motor stop switch 36 is pressed and operated by the user, the controller 48 does not start driving the electric motor 20. It's like Also, when both the motor drive switch 34 and the electromagnet switch 38 are operated within a very short time and the controller 48 determines that the two switches 34 and 38 are operated simultaneously, the controller 48 operates the electromagnet switch 38. , the operation of the electromagnet 12 is started or stopped without starting the driving of the electric motor 20 . Alternatively, when both the motor drive switch 34 and the motor stop switch 36 are operated within a very short period of time and the controller 48 determines that the two switches 34 and 36 are operated simultaneously, the controller 48 stops the motor. Priority is given to the operation of the switch 36, and the electric motor 20 is stopped without starting the driving of the electric motor 20. - 特許庁This makes it possible to prevent the electric motor 20 from being driven unintentionally when the motor drive switch 34 is erroneously operated.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, instead of the annular cutter, the machine tool may be configured so that other end tools such as a drill can be attached. Moreover, although the battery is used as the main power supply in the above embodiment, an external power supply such as an AC power supply may be used as the main power supply. The motor drive switch and the motor stop switch for operating the drive of the electric motor may be composed of a single motor switch, such as an electromagnet switch, capable of both driving and stopping the electric motor. The motor switch may be a momentary switch that switches between driving and stopping each time it is pressed, or may be an alternate switch that switches between ON and OFF states to switch between driving and stopping. When such a motor switch is employed, when the motor switch is operated to start driving the electric motor while the electromagnet switch is being operated by the user, the control unit starts driving the electric motor. prevent it from starting.

1 Portable Machine Tool 10 Machine Tool Body 12 Electromagnet 14 Battery 16 Annular Cutter 18 Machining Tool Attachment 20 Electric Motor 22 Gear Mechanism 24 Lever 26 First Coil 30 Second Coil 34 Motor Drive Switch 36 Motor Stop Switch 38 Electromagnet Switch 40 Lighting Switch 41 LED display section 42 Magnetic sensor 46 Control circuit board 48 Control section 50 Control power supply circuit 52 Motor control section 54 Motor current detection section 56 Coil control circuit 58 Coil disconnection detection circuit 60 Power supply voltage detection circuit

Claims (4)

A portable machine tool,
machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a controller configured to control driving of the electromagnet and the electric motor;
an electromagnet switch connected to the controller for manipulating actuation of the electromagnet;
a motor stop switch connected to the control unit for stopping driving of the electric motor;
a motor drive switch connected to the controller for starting to drive the electric motor;
with
The control unit drives the electric motor when the motor drive switch is operated while at least one of the electromagnet switch and the motor stop switch is operated by the user of the portable machine tool. A portable machine tool that is prevented from starting When the controller determines that the motor drive switch and the electromagnet switch are operated at the same time, it starts or stops the operation of the electromagnet without starting the drive of the electric motor, and controls the motor drive switch and the motor. 2. The portable machine tool according to claim 1, wherein the electric motor is stopped without starting the driving when it is determined that both the stop switch and the stop switch have been operated at the same time. 3. The portable machine tool according to claim 1, wherein said electromagnet switch, said motor stop switch, and said motor drive switch are momentary switches which are turned ON only when they are respectively operated. the motor drive switch and the motor stop switch are composed of one motor switch,
The controller starts driving the electric motor when the motor switch is operated to start driving the electric motor while the electromagnet switch is being operated by the user of the portable machine tool. 4. A portable machine tool according to any one of claims 1 to 3, adapted to prevent

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