JP2001030183A - Rotary power tool with portable power supply unit having automatic stop mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic stop mechanism to properly provide a torque control function in a simple constitution and further improve easiness of movement by bringing this device into a cordless type and the efficiency of various works. SOLUTION: A rotary tool, such as a drive pit, is coupled to the output shaft of an electric motor 22 and a work, such as fastening of a screw accompanying a rotary tool, through drive of the electric motor 22. A torque detecting means is provided to detect load torque generated at the rotary tool occasioned by completion of a given work. An automatic stop mechanism is provided to stop drive of the electric motor by disconnecting coupling between the output shaft of the electric motor 22 and the rotary tool when the load torque attains a preset torque value. A so formed rotary power tool is provided with a control means 24 to cut off a power source for the electric motor 22 based on a detecting signal from a torque detecting means to detect that load torque attains a preset torque value, and a chargeable secondary battery 26 serving as a power source to drive the electric motor 22. The control means and the secondary battery are integrally coupled together and rendered portable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric rotary tool such as an electric screwdriver, and more particularly to a power supply that can be moved without being restricted by a location when using the electric rotary tool. Power cut-off device with a clutch mechanism that can control torque
The present invention relates to an electric rotating tool with a portable power supply device having an automatic stop mechanism capable of always achieving a proper work of tightening a screw or the like.

[0002]

2. Description of the Related Art Conventionally, in the case of an electric screwdriver or the like, when a strong opposite load is applied to a driver bit when tightening a screw or the like, a predetermined torque value is obtained by a clutch mechanism operating with a preset tightening torque. Has been proposed and implemented in such a manner that the state of the electric motor is detected and the clutch mechanism is actuated to temporarily cut off the connection between the output shaft of the electric motor and the driver bit. Further, an electric driver or the like configured to detect the state by a limit switch or the like when the clutch mechanism is operated and stop driving the electric motor has been put into practical use (Japanese Patent Publication No. 60-13798).

On the other hand, a switching circuit is provided in a power supply circuit such as an electric screwdriver having a driver bit that is driven to rotate by an electric motor, and a load current flowing in the power supply circuit when the electric motor is driven is close to completion of screw tightening. When a predetermined tightening torque is reached, the overload current increases to a predetermined value or more.Therefore, this state is detected and the supply of the drive current to the electric motor is cut off. The supply of the drive current is restored, and further, a switching mechanism is provided in the armature circuit of the electric motor, and when the switching circuit cuts off the supply of the drive current to the electric motor, the armature circuit of the electric motor is turned off. There has also been proposed an electric screwdriver or the like having an automatic power cutoff device configured to short-circuit and stop the electric motor instantaneously by regenerative braking ( Sho 57-43389 JP). Since the switching circuit is turned off only for a certain period of time, when the next screw tightening operation is performed, the switching circuit automatically returns to the ON state and the electric motor is driven to perform the next screw tightening operation. It has a function that can be started immediately.

As described above, in a conventional electric rotating tool such as an electric screwdriver, a state in which a tightening torque reaches a predetermined torque value when a screw or the like is tightened is detected by a power supply circuit of a built-in electric motor. It is necessary to provide a controller for interrupting the supply of the drive current to the electric motor and automatically resetting the drive current via the torque detecting means.

For this reason, in the conventional electric rotary tool 10, as shown in FIG. 4, when the built-in electric motor 12 is connected to a power supply, a control circuit 14 for performing the above-described torque control and a predetermined DC voltage are applied. It was necessary to connect to a commercial power supply 18 using a power outlet 17 via a controller 16 having a DC conversion mechanism (transformer) 15 for obtaining the power.

[0006]

However, at present, the electric rotary tool provided with the above-mentioned automatic stop mechanism is not limited to machining,
It is widely used for electrical work and construction work, and greatly contributes to improving work efficiency.

[0007] In these operations, for example, in the assembly process of a production line, in order to adapt to high-mix low-volume production,
It is required to flexibly change the assembly process of the production line. That is, in this case, it is necessary to freely change the arrangement on the production line using the electric rotating tool. Therefore, if the position of the outlet of the commercial power supply is fixed,
Not only is the range of movement of the electric rotary tool limited, but also the power supply connection cords are complicatedly extended or crossed, causing various troubles.

Also, in the assembly process of a production line using an air driver powered by pneumatic pressure, when the production line is changed in the same manner as described above, a great deal of work and cost are required for changing the equipment of the air piping. In addition, there is a problem that the workability is deteriorated due to the restriction by the air piping.

In order to overcome such difficulties, it is effective to attach a power source device using a secondary battery having a portable and movable charging function, and to apply a cordless electric rotating tool. It is. However, it is difficult to properly perform the control for performing the torque control simply by setting the power supply device to drive the electric motor by using a secondary battery instead of the conventional commercial power supply.

The inventor of the present invention has conducted intensive research and trial production, and as a result, based on the detection signal of the torque detecting means when detecting that the load torque has reached a preset torque value, turns on the power supply of the electric motor. A control means including a control circuit for shutting off and a chargeable and movable secondary battery as a power supply for driving the electric motor are provided. By making it possible, a torque control function can be properly exhibited with a simple configuration, and an automatic stop mechanism that can further enhance various work efficiencies associated with ease of movement due to cordlessness is provided. It has been found that an electric rotating tool with a portable power supply can be obtained.

Accordingly, an object of the present invention is to enable the torque control function to be properly exerted with a simple configuration, and
It is an object of the present invention to provide an electric rotating tool with a portable power supply device having an automatic stop mechanism capable of further improving the ease of movement and the improvement of various work efficiencies due to the cordless operation.

[0012]

In order to achieve the above object, an electric rotating tool with a portable power supply device having an automatic stop mechanism according to the present invention comprises a rotating tool such as a driver bit on an output shaft of an electric motor. The electric motor further includes a torque detecting unit that detects a load torque generated in the rotary tool upon completion of the predetermined operation, while performing an operation such as screw tightening of the rotary tool by driving the electric motor. In the electric rotating tool provided with an automatic stop mechanism for stopping the drive of the electric motor by cutting off the connection between the output shaft of the electric motor and the rotating tool when the set torque value is reached, the load torque is set to a preset torque. Control means for shutting off the power of the electric motor based on a detection signal of the torque detecting means when detecting that the electric motor has reached the value, and a power supply for driving the electric motor. And a rechargeable secondary battery of Te is provided,
It is characterized in that these control means and the secondary battery are integrally connected to each other so as to be portable.

In this case, the control means and the secondary battery are housed and arranged in one casing, and a connector for directly connecting to an electric motor of an electric rotating tool, a power ON / OFF switch is provided in a part of the casing. , A connector for connecting to an AC adapter for charging the secondary battery, and portable holding means.

[0014] Alternatively, a secondary battery can be detachably attached to a casing in which the control means is housed and arranged, and a connector for directly connecting to an electric motor of an electric rotating tool is provided in a part of the casing. Power ON /
OFF switch and portable holding means are provided respectively,
The secondary battery may be configured to be independently connected to an AC adapter for charging the secondary battery.

On the other hand, the control means detects a state in which a predetermined torque value is reached by torque detecting means comprising a clutch mechanism which operates with a preset tightening torque when a strong opposite load is applied to the driver bit. Activating the clutch mechanism to temporarily disconnect the connection between the output shaft of the electric motor and the driver bit, and detecting the operation of the clutch mechanism by a limit switch to stop driving the electric motor. Can be configured.

[0016] Further, the control means, as a torque detecting means, when the load current flowing through the power supply circuit when the electric motor is driven approaches the completion of screw tightening and reaches a predetermined tightening torque, reaches a predetermined value or more. A switching circuit is provided which increases the overload current, detects this state, cuts off the supply of the drive current to the electric motor, and resumes the supply of the drive current to the electric motor after a certain period of time. A switching mechanism for the armature circuit is provided so that when the switching circuit cuts off the supply of the drive current to the electric motor, the armature circuit of the electric motor is short-circuited, and the electric motor is instantaneously stopped by regenerative braking. Can be configured.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an electric rotary tool with a portable power supply device having an automatic stop mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a system configuration of an electric rotary tool with a portable power supply device having an automatic stop mechanism according to the present invention. That is, in FIG. 1, reference numeral 20 indicates an electric rotating tool such as an electric screwdriver,
This electric rotating tool 20 is a portable power supply device 28 integrally formed with a control means 24 including a control circuit for controlling torque and a rechargeable secondary battery 26 as a power supply for a built-in electric motor 22. Is connected. The secondary battery 26 is configured to be connected to a commercial power supply 40 via an AC adapter 37 and to be charged.

However, the control means 24
The power supply of the electric motor 22 is cut off based on a detection signal of the torque detecting means when detecting that the load torque of the electric rotating tool 20 has reached a preset torque value.

As shown in FIG. 2, for example, the portable power supply device 28 accommodates and arranges the control means 24 and the secondary battery 26 in a single casing. Electric motor 2 of tool 20
32 which is directly connected to 2 and power ON / OFF
A switch 34, an AC adapter connector 36 for connecting to a commercial power supply 40 for charging the secondary battery 26,
A configuration in which the portable holding means 38 and the portable holding means 38 are provided respectively can be adopted.

As an alternative, the portable power supply 28
As shown in FIG. 3, a secondary battery 26 is configured to be detachable from a casing 30 that houses and arranges the control means 24, and a part of the casing 30 includes an electric motor of the electric rotating tool 20 as described above. A connector 32 directly connected to the power supply 22, a power ON / OFF switch 34, and a portable holding unit 38 are provided. The secondary battery 26 may be separated from the casing 30 and connected to a commercial power supply 40 by an AC adapter 37 via a charger 42 so that the secondary battery 26 can be charged.

On the other hand, as the control means 24, for example, when a strong opposite load is applied to the driver bit of the electric rotary tool 20, the torque is detected by a torque detecting means comprising a clutch mechanism which operates with a preset tightening torque. Known means configured to detect a state in which a predetermined torque value has been reached, actuate the clutch mechanism, and temporarily disconnect the coupling between the output shaft of the electric motor and the driver bit can be employed. . When the clutch mechanism is operated, the state may be detected by a limit switch or the like, the supply of the drive current to the electric motor 22 may be cut off, and the drive may be stopped.

The control means 24 serves as a torque detecting means. When the load current flowing through the power supply circuit when the electric motor 22 is driven approaches the completion of screw tightening and reaches a predetermined tightening torque, the control means 24 operates as a torque detecting means. Since the overload current increases to a value greater than or equal to the value, the supply of the drive current to the electric motor 22 is interrupted by detecting this state, and the supply of the drive current to the electric motor 22 is restored after a certain time has elapsed. A switching circuit for the electric motor 22 is provided, and a switching mechanism for the armature circuit of the electric motor 22 is provided. When the switching circuit cuts off the supply of the driving current to the electric motor 22, the armature circuit of the electric motor 22 is turned off. It may be configured such that a short circuit occurs and the electric motor is stopped instantaneously by regenerative braking.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the present invention can be modified in many ways without departing from the spirit of the invention. it can.

[0025]

As is apparent from the above-described embodiment, according to the electric rotary tool with a portable power supply provided with the automatic stop mechanism according to the present invention, a rotary tool such as a driver bit is connected to the output shaft of the electric motor. The electric motor further includes a torque detecting means for performing a work such as screw tightening of the rotating tool by driving the electric motor, and detecting a load torque generated in the rotating tool upon completion of the predetermined work, wherein the load torque is set in advance. An electric rotating tool provided with an automatic stop mechanism for stopping the drive of the electric motor by interrupting the connection between the output shaft of the electric motor and the rotating tool when the torque value reaches the set torque value. Control means for shutting off the power supply of the electric motor based on a detection signal of the torque detection means when it is detected that the electric motor has reached, and a power supply for driving the electric motor. A rechargeable secondary battery is provided, and these control means and the secondary battery are integrally connected to form a portable configuration, so that the torque control function can be properly exerted with a simple configuration. At the same time, the ease of movement due to the cordless operation and the improvement of various work efficiencies can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of a system configuration of an electric rotating tool with a portable power supply device having an automatic stop mechanism according to the present invention.

FIG. 2 is a perspective view showing a specific configuration example of the portable power supply device shown in FIG.

FIG. 3 is a schematic explanatory view showing a modification of the portable power supply device shown in FIGS. 1 and 2.

FIG. 4 is a schematic explanatory view showing a system configuration example of a conventional electric rotary tool having an automatic stop mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Electric rotary tool 22 Electric motor 24 Control means 24 26 Secondary battery 28 Portable power supply 30 Casing 32 Connector 34 ON / OFF switch 36 AC adapter connector 37 AC adapter 38 Portable holding means 40 Commercial power supply 42 Charger

Claims (5)

[Claims] 1. A rotating tool such as a driver bit is coupled to an output shaft of an electric motor to perform operations such as screw tightening of the rotating tool by driving the electric motor, and a rotating tool accompanying completion of the predetermined operation. Automatic detecting means for detecting the load torque generated in the motor, and automatically stopping the drive of the electric motor by cutting off the connection between the output shaft of the electric motor and the rotary tool when the load torque reaches a preset torque value. An electric rotating tool provided with a stop mechanism, wherein the control means cuts off a power supply of the electric motor based on a detection signal of a torque detecting means when detecting that the load torque has reached a preset torque value; A rechargeable secondary battery as a power source for driving the motor is provided, and these control means and the secondary battery are integrally connected to each other so as to be portable. Portable power unit with an electric rotary tool having an automatic stop mechanism according to claim. 2. A control device and a secondary battery are housed and arranged in one casing, and a connector for directly connecting to an electric motor of an electric rotating tool, a power ON / OFF switch, The electric rotary tool with a portable power supply device having an automatic stop mechanism according to claim 1, further comprising a connector for connecting to an AC adapter for charging a secondary battery, and a portable holding means. 3. A rechargeable battery is detachably mounted on a casing in which the control means is housed and arranged. A connector directly connected to an electric motor of an electric rotating tool is provided on a part of the casing, and a power supply is turned on / off. 2. A portable device having an automatic stop mechanism according to claim 1, wherein an OFF switch and portable holding means are provided, respectively, so that the secondary battery can be connected independently to an AC adapter for charging the secondary battery. Electric rotating tool with power supply. 4. The control means detects a state in which a predetermined torque value is reached by torque detecting means comprising a clutch mechanism which operates with a preset tightening torque when a strong opposite load is applied to the driver bit, The clutch mechanism is operated to temporarily disconnect the connection between the output shaft of the electric motor and the driver bit, and the operation of the electric motor is stopped by detecting the operation of the clutch mechanism by a limit switch. An electric rotary tool with a portable power supply device, comprising the automatic stop mechanism according to claim 1 configured as described above. 5. The control means as a torque detection means, wherein when a load current flowing through a power supply circuit when the electric motor is driven reaches a predetermined tightening torque near the completion of screw tightening, an excess of a predetermined value or more is obtained. A switching circuit is provided which increases the load current, detects this state, interrupts the supply of the drive current to the electric motor, and resumes the supply of the drive current to the electric motor after a certain period of time. A switching mechanism for the slave circuit, wherein the switching circuit short-circuits the armature circuit of the electric motor when the switching circuit interrupts the supply of the drive current to the electric motor, and the electric motor is instantaneously stopped by regenerative braking. An electric rotary tool with a portable power supply device, comprising the automatic stop mechanism according to claim 1.