Electric screwdriver

Abstract

To provide an electric screwdriver which attracts and holds a screw with constant magnetic force, and can stably perform operations for attaching and detaching the screw.SOLUTION: An electric screwdriver includes: a body; a driver bit rotatably attached to the body; a motor for rotating the driver bit; a drive circuit for driving the motor; a magnetization circuit for magnetizing the driver bit; and a shared battery which supplies electric power to the drive circuit and the magnetization circuit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electric screwdriver having a function of magnetizing a driver bit. [Background technology]

[0002] For example, a driver is known that includes a main body made of a non-magnetic material, a permanent magnet housed in the main body, and a driver bit made of a magnetic material that is attached to the main body so as to face the permanent magnet, and in which the driver bit is magnetized by the permanent magnet so that it can attract and hold screws (for example, Patent Document 1).

[0003] Also known is a driver in which a cylindrical magnetic attachment aid is attached to surround a driver bit made of a magnetic material, and the driver bit is magnetized by the magnetic attachment aid (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-25242 [Patent Document 2] Patent No. 6085740 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the screwdrivers disclosed in Patent Documents 1 and 2, the strength of the magnetic force of the driver bit varies from one individual to another, and there is a risk that the screw cannot be attracted and held with a constant magnetic force.

[0006] Furthermore, in the case of the screwdriver disclosed in Patent Document 2, the diameter of the magnetic attachment aid is larger than the diameter of the driver bit, so when attempting to attach or remove a screw in a relatively narrow space, the magnetic attachment aid may interfere with objects around the screw, or the driver bit may be attracted to metal objects around the screw via the magnetic attachment aid, raising the risk that the magnetic attachment aid may interfere with attaching or removing the screw.

[0007] The present invention has been made in consideration of the above-mentioned problems, and one object of the present invention is to provide an electric screwdriver that can attract and hold screws with a constant magnetic force, enabling stable screw installation and removal operations. [Means for solving the problem]

[0008] One of the present inventions for achieving the above-mentioned object is an electric screwdriver including a main body, a driver bit rotatably attached to the main body, a motor for rotating the driver bit, a drive circuit for driving the motor, a magnetization circuit for magnetizing the driver bit, and a shared battery for supplying power to the drive circuit and the magnetization circuit.

[0009] According to the electric screwdriver of the present invention, when installing and removing screws, the driver bit is electrically magnetized using a magnetization circuit, making it possible to magnetize the driver bit with a preset constant magnetic force regardless of the age of the electric screwdriver or the surrounding environment in which the electric screwdriver is used.

[0010] Another aspect of the present invention for achieving the above-mentioned object is an electric screwdriver in which the magnetization circuit includes a coil wound around the driver bit centered on the axis of rotation of the driver bit, and a variable resistor that adjusts the magnitude of the current flowing through the coil, and is housed in the main body.

[0011] According to the electric screwdriver of the present invention, the current flowing through the coil can be adjusted by the variable resistor, so that it is possible to adjust the strength of the magnetic force that magnetizes the screwdriver bit according to the size and type of the screw. In addition, when multiple electric screwdrivers are prepared to install and remove multiple screws of the same type, it is possible to set the magnetic force that magnetizes the driver bit of each electric screwdriver to a constant strength by adjusting the resistance value of the variable resistor provided in each electric screwdriver. In addition, since the magnetization circuit is housed in the main body, it is possible to perform stable work even in a relatively narrow space where the screw installation and removal work is performed.

[0012] Another aspect of the present invention for achieving the above-mentioned object is an electric screwdriver including a first switch that energizes the drive circuit and a second switch that energizes the magnetization circuit independently of the first switch.

[0013] According to the electric screwdriver of the present invention, it is possible to appropriately adjust the timing of magnetizing the driver bit and the timing of rotating the driver bit according to the process when an operator installs or removes a screw. Also, when it is not necessary to energize the drive circuit, for example, when adsorbing and picking up a dropped screw during installation or removal, it is possible to independently energize only the magnetization circuit.

[0014] In order to achieve the above object, another aspect of the present invention is an electric screwdriver including a switch that energizes the drive circuit and the magnetization circuit in conjunction with each other.

[0015] According to the electric screwdriver of the present invention, by linking the timing of magnetization and rotation of the driver bit, it becomes possible to efficiently perform screw installation and removal operations. For example, it is possible to rotate the driver bit at the same time as magnetizing it, or to rotate it after a certain time (for example, 1 to 2 seconds) has elapsed since magnetizing the driver bit.

[0016] Another aspect of the present invention for achieving the above-mentioned object is an electric screwdriver, in which the main body includes a chuck portion that holds one end of the driver bit so that the driver bit is attached so as to be freely rotatable, and the coil is disposed between the chuck portion and the one end of the driver bit held by the chuck portion.

[0017] According to the electric screwdriver of the present invention, by disposing the coil inside the chuck portion, it is possible to efficiently accommodate the magnetization circuit within the main body.

[0018] In addition, the problems and solutions disclosed in this application will be made clear by the description in the section of the preferred embodiment of the invention and the descriptions in the drawings. Effect of the Invention

[0019] According to the present invention, it is possible to provide an electric screwdriver that attracts and holds screws with a constant magnetic force, enabling stable screw installation and removal operations even in a relatively narrow space. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing an example of the appearance of an electric screwdriver 1. [Diagram 2] 1 is a block diagram showing the main functions of an electric screwdriver 1. FIG. [Diagram 3] 4 is an enlarged view of a main portion showing an example of the arrangement position of a coil 52 of a magnetization circuit 50. FIG. [Figure 4] 1 is a diagram showing the connection between the drive circuit 40 and the magnetization circuit 50 and the shared battery 60. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] At least the following matters will become apparent from the description of this specification and the accompanying drawings. Hereinafter, the present invention will be described in detail based on an embodiment thereof with reference to the accompanying drawings.

[0022] Fig. 1 is a diagram showing an example of the appearance of an electric screwdriver 1. Fig. 2 is a block diagram showing main functions of the electric screwdriver 1. Fig. 3 is an enlarged view of a main part showing an example of the arrangement position of the coil 52 of the magnetization circuit 50. Fig. 4 is a diagram showing the connection between the drive circuit 40 and the magnetization circuit 50 and the shared battery 60.

[0023] The electric screwdriver 1 is a power tool that has the function of magnetizing the driver bit 10 so that a screw can be attracted to the tip of the driver bit 10 when performing an attachment operation to attach a screw to an object, and an removal operation to remove a screw attached to an object from the object.

[0024] In order to realize the above functions, the electric screwdriver 1 includes a driver bit 10, a main body 20, a motor 30, a drive circuit 40, a magnetization circuit 50, and a shared battery 60.

[0025] The driver bit 10 is formed into an elongated shape such as a cylinder or a rectangular column using a magnetic material, and the tip 11 of the driver bit 10 has a shape that fits into a thread groove formed in the head of a screw made of a magnetic material. For example, if the thread groove of the head of the screw is a Phillips head, the tip 11 of the driver bit 10 has a Phillips head that fits into the thread groove of the head of the screw. Here, the driver bit 10 and the screw are formed from a magnetic material that is mainly made of a metal material such as iron or nickel.

[0026] The main body 20 has a shape with a grip portion 21 that can be held by the hand so that the operator can easily perform screw installation and removal operations. The overall shape of the main body 20 may be either a pistol shape or a pen shape, but in this embodiment, the pen shape will be described as an example. The main body 20 is formed using, for example, a non-magnetic material so that it is not magnetized by the magnetization circuit 50. Here, the non-magnetic material used for the main body 20 is, for example, a metal material such as aluminum, austenitic stainless steel (SUS303, SUS304, etc.), titanium, titanium alloy, etc. It should be noted that the main body 20 may be formed using, for example, a resin material instead of a non-magnetic material.

[0027] The main body 20 has a hollow space 22 therein. The hollow space 22 accommodates a motor 30, a drive circuit 40, a magnetization circuit 50, and a shared battery 60.

[0028] The driver bit 10 is attached to the main body 20 so that it can rotate in the forward or reverse direction around a rotation axis 12, which is a dashed line along the longitudinal direction of the driver bit 10, as shown in Fig. 1. Specifically, the main body 20 has a chuck portion 23 to which the driver bit 10 can be detached, on the side opposite to the side on which the grip portion 21 is provided, and the tip 13 of the driver bit 10 opposite the tip 11 is held by the chuck portion 23 so that the driver bit 10 can rotate freely in both the forward and reverse directions. In this way, the tip 13 of the driver bit 10 attached to the main body 20 is connected to the rotation axis 31 of the motor 30, and the rotational force of the motor 30 is transmitted.

[0029] For example, a three-phase brushless DC motor that rotates in both the forward and reverse directions can be used as the motor 30. In other words, when the motor 30 rotates in the forward direction, the forward rotational force of the motor 30 is transmitted to the driver bit 10, causing it to rotate in the forward direction, and when the motor 30 rotates in the reverse direction, the reverse rotational force of the motor 30 is transmitted to the driver bit 10, causing it to rotate in the reverse direction. The motor 30 is connected to a shared battery 60, which is the power source for the motor 30.

[0030] The drive circuit 40 is a circuit that switches the direction of rotation of the motor 30 according to logic for executing a forward rotation mode in which the motor 30 rotates in a forward direction and a reverse rotation mode in which the motor 30 rotates in a reverse direction. The logic for the forward rotation mode executed by the drive circuit 40 defines the direction of the current supplied to each phase of the motor 30 and the order in which the current is supplied to each phase of the motor 30, which are necessary for rotating the motor 30 in the forward direction. The logic for the reverse rotation mode executed by the drive circuit 40 defines the direction of the current supplied to each phase of the motor 30 and the order in which the current is supplied to each phase of the motor 30, which are necessary for rotating the motor 30 in the reverse direction.

[0031] The drive circuit 40 includes a first switch 41 and a control circuit 42.

[0032] The first switch 41 is a switch that selects one of a forward rotation mode, a reverse rotation mode, and a stop mode. The control circuit 42 is a circuit that rotates the motor 30 in the forward direction, reverse direction, or stops it according to the mode selected by the first switch 41. Specifically, when the drive circuit 40 is energized with the first switch 41 in the position for selecting the forward rotation mode, the control circuit 42 rotates the motor 30 in the forward direction according to the logic of the forward rotation mode. When the drive circuit 40 is energized with the first switch 41 in the position for selecting the reverse rotation mode, the control circuit 42 rotates the motor 30 in the reverse direction according to the logic of the reverse rotation mode. When the drive circuit 40 is de-energized with the first switch 41 in the position for selecting the stop mode, the control circuit 42 stops the supply of current to the motor 30 and stops the rotation of the motor 30.

[0033] The first switch 41 is a mechanical switch, and is a slide switch having, for example, a first position for selecting a forward rotation mode, a second position for selecting a reverse rotation mode, and a third position for selecting a stop mode along a slide trajectory. In FIG. 1, the slide positions of the first switch 41 are the first position, the third position, and the second position from the left to the right of the page. The first position, the third position, and the second position are marked with the characters "forward", "stop", and "reverse", respectively. That is, when the first switch 41 slides to the first position, the control circuit 42 rotates the motor 30 in the forward direction according to the logic of the forward rotation mode, when the first switch 41 slides to the second position, the control circuit 42 rotates the motor 30 in the reverse direction according to the logic of the reverse rotation mode, and when the first switch 41 slides to the third position, the control circuit 42 stops the rotation of the motor 30. The first switch 41 is provided exposed at a position adjacent to the grip portion 21 so that the worker can easily operate it when installing and removing screws.

[0034] The magnetization circuit 50 is a circuit that magnetizes the driver bit 10 attached to the main body 20. The magnetization circuit 50 includes a circuit in which a second switch 51, a coil 52, and a variable resistor 53 are connected in series. The drive circuit 40 and the magnetization circuit 50 are connected in parallel to a shared battery 60 which is the power source for the drive circuit 40 and the magnetization circuit 50.

[0035] The second switch 51 is a switch that closes to energize the magnetization circuit 50 when the driver bit 10 is to be magnetized, and opens to de-energize the magnetization circuit 50 when the driver bit 10 is not to be magnetized.

[0036] The second switch 51 is a mechanical switch, and is, for example, a slide switch having a fourth position for selecting a magnetization mode and a fifth position for selecting a magnetization stop mode along a slide trajectory. In FIG. 1, the second switch 51 is slid to the fourth position on the left side of the paper and to the fifth position on the right side of the paper. The fourth and fifth positions are marked with the characters "magnet" and "stop." That is, when the second switch 51 slides to the fourth position, the magnetization circuit 50 is energized and magnetizes the driver bit 10. When the second switch 51 slides to the fifth position, the magnetization circuit 50 is deenergized and stops magnetizing the driver bit 10. The second switch 51 is provided adjacent to the grip portion 21 and exposed at a position below the first switch 41 so that the worker can easily operate the second switch 51 when performing screw installation and removal operations.

[0037] The first switch 41 and the second switch 51 can be slid independently. In other words, the timing of magnetizing the driver bit 10 and the timing of rotating the driver bit 10 can be appropriately adjusted according to the process when the worker attaches or removes the screw. The first switch 41 and the second switch 51 may be slid in conjunction with each other. In this case, depending on the timing of attaching the screw to the driver bit 10, the driver bit 10 can be magnetized and rotated at the same time, or rotated several seconds after the driver bit 10 is magnetized.

[0038] 3, coil 52, which is a component of magnetization circuit 50, is disposed inside chuck portion 23 of main body 20. Coil 52 is disposed between the inside of chuck portion 23 and the outer circumferential surface of tip 13 of driver bit 10 such that tip 13 of driver bit 10 is inserted into coil 52 when tip 13 of driver bit 10 is held by chuck portion 23 so that driver bit 10 can freely rotate in both forward and reverse directions.

[0039] The variable resistor 53 is a means for adjusting the magnitude of the current flowing through the coil 52. When the second switch 51 is slid to the fourth position to energize the magnetization circuit 50, a current flows through the coil 52 and the driver bit 10 is magnetized. At this time, the magnitude of the current flowing through the coil 52 is changed by the resistance value of the variable resistor 53. For example, when the resistance value of the variable resistor 53 is adjusted in a direction to decrease, the current flowing through the coil 52 increases, and the magnetic force for magnetizing the driver bit 10 increases. On the other hand, when the resistance value of the variable resistor 53 is adjusted in a direction to increase, the current flowing through the coil 52 decreases, and the magnetic force for magnetizing the driver bit 10 decreases. In this way, by appropriately adjusting the resistance value of the variable resistor 53, it is possible to magnetize the driver bit 10 with a constant magnetic force. The resistance value of the variable resistor 53 can be adjusted by, for example, a circular adjustment dial 54 as shown in FIG. 1. The adjustment dial 54 is provided, for example, adjacent to the left side of the first switch 41 and the second switch 51 on the paper surface. For example, when the adjustment dial 54 is turned counterclockwise, the resistance value of the variable resistor 53 can be adjusted to decrease, and when the adjustment dial 54 is turned clockwise, the resistance value of the variable resistor 53 can be adjusted to increase.

[0040] The shared battery 60 is a secondary battery that can be charged from a household power source or the like. The shared battery 60 may be built into the main body 20, or may be detachable from the main body 20. As the shared battery 60, for example, any of secondary batteries such as a nickel-cadmium battery, a nickel-metal hydride battery, or a lithium-ion battery can be used.

[0041] When performing an installation work for installing a screw in an object using the electric screwdriver 1 configured as described above, first, the adjustment dial 54 is turned to set the magnitude of the magnetic force when magnetizing the driver bit 10. Next, the second switch 51 is slid to the fourth position to energize the magnetization circuit 50, and the driver bit 10 is magnetized with the set magnitude of magnetic force. Next, the tip 11 of the magnetized driver bit 10 is fitted into the thread groove of the screw, and the screw is attracted to the driver bit 10. Next, the screw attracted to the driver bit 10 is pressed against the screw hole of the object. Finally, the first switch 41 is slid to the first position to energize the drive circuit 40, and the driver bit 10 is rotated in the forward direction to install the screw in the object.

[0042] On the other hand, when using the electric screwdriver 1 to remove a screw attached to an object, first, the adjustment dial 54 is turned to set the magnitude of the magnetic force to be used to magnetize the driver bit 10. Next, the second switch 51 is slid to the fourth position to energize the magnetization circuit 50, and the driver bit 10 is magnetized with the set magnitude of magnetic force. Next, the tip 11 of the magnetized driver bit 10 is fitted into and pressed against the thread groove of the screw attached to the object. Finally, the first switch 41 is slid to the second position to energize the drive circuit 40, and the driver bit 10 is rotated in the reverse direction to remove the screw from the object.

[0043] As described above, the electric screwdriver 1 includes a main body 20, a driver bit 10 rotatably attached to the main body 20, a motor 30 that rotates the driver bit 10, a drive circuit 40 that drives the motor 30, a magnetization circuit 50 that magnetizes the driver bit 10, and a shared battery 60 that supplies power to the drive circuit 40 and the magnetization circuit 50.

[0044] According to the electric screwdriver 1, when installing and removing screws, the driver bit 10 is electrically magnetized using the magnetization circuit 50, so that the driver bit 10 can be magnetized with a preset constant magnetic force regardless of the age of the electric screwdriver 1 or the surrounding environment in which the electric screwdriver 1 is used.

[0045] In addition, in the electric screwdriver 1, the magnetization circuit 50 includes a coil 52 wound around the driver bit 10 centered on the rotation axis 12 in the longitudinal direction of the driver bit 10, and a variable resistor 53 that adjusts the magnitude of the current flowing through the coil 52, and is housed in the main body 20.

[0046] According to the electric screwdriver 1, the current flowing through the coil 52 can be adjusted by the variable resistor 53, so that it is possible to adjust the strength of the magnetic force magnetizing the screwdriver bit 10 according to the size and type of the screw. In addition, when multiple electric screwdrivers 1 are prepared to perform the work of attaching and removing multiple screws of the same type, it is possible to set the magnetic force magnetizing the driver bit 10 of each electric screwdriver 1 to a constant strength by adjusting the resistance value of the variable resistor 53 provided in each electric screwdriver 1. In addition, since the magnetization circuit 50 is housed in the main body 20, it is possible to perform stable work even if the space in which the work of attaching and removing screws is performed is relatively narrow.

[0047] The electric screwdriver 1 further includes a first switch 41 that energizes the drive circuit 40 and a second switch 51 that energizes the magnetization circuit 50 independently of the first switch 41.

[0048] According to the electric screwdriver 1, it is possible to appropriately adjust the timing for magnetizing the driver bit 10 and the timing for rotating the driver bit in accordance with the process when an operator attaches or removes a screw. Also, when it is not necessary to energize the drive circuit 40, for example, when adsorbing and picking up a dropped screw during an attachment or removal operation, it is possible to independently energize only the magnetization circuit 50.

[0049] The electric screwdriver 1 may also include a switch that energizes the drive circuit 40 and the magnetization circuit 50 in conjunction with each other.

[0050] The electric screwdriver 1 enables efficient screw attachment and removal by coordinating the timing of magnetization and rotation of the driver bit 10. For example, it is possible to rotate the driver bit 10 simultaneously with magnetization, or to rotate the driver bit 10 after a certain time (e.g., 1 to 2 seconds) has elapsed since magnetization.

[0051] In addition, in the electric screwdriver 1, the main body 20 includes a chuck portion 23 that holds the tip 13 of the driver bit 10 so that the driver bit 10 is attached so as to be freely rotatable, and the coil 52 is disposed in the space between the chuck portion 23 and the tip 13 of the driver bit 10 held by the chuck portion.

[0052] According to the electric screwdriver 1, by disposing the coil 52 in the space inside the chuck portion 23, it is possible to efficiently accommodate the magnetization circuit 50 in the main body 20.

[0053] It should be noted that the present embodiment is provided for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and equivalents thereof are also included in the present invention. [Explanation of symbols]

[0054] 1 Electric screwdriver 10 Driver Bits 11,13 Tip 12,31 Rotation axis 20 Main unit 21 Grip section 22 Hollow space 23 Chuck part 30 Motor 40 Drive circuit 41 First Switch 42 Control circuit 50 Magnetization circuit 51 Second Switch 52 Coil 53 Variable Resistor 54 Adjustment dial 60 Shared Battery

Claims

1. The main body, A driver bit rotatably attached to the main body; A motor that rotates the driver bit; A drive circuit for driving the motor; a magnetizing circuit for magnetizing the driver bit; a shared battery for supplying power to the driving circuit and the magnetizing circuit; Includes a power screwdriver.

2. 2. The electric screwdriver according to claim 1, The magnetization circuit includes: A coil wound around the driver bit and centered on a rotation axis of the driver bit; A variable resistor that adjusts the magnitude of the current flowing through the coil, Housed in the body Electric screwdriver.

3. 3. The electric screwdriver according to claim 2, A first switch for energizing the drive circuit; a second switch that energizes the magnetization circuit independently of the first switch; Includes a power screwdriver.

4. 3. The electric screwdriver according to claim 2, a switch that energizes the drive circuit and the magnetization circuit in conjunction with each other; Includes a power screwdriver.

5. 3. The electric screwdriver according to claim 2, The main body includes a chuck portion that holds one end of the driver bit so that the driver bit is rotatably attached, The coil is disposed between the chuck portion and one end of the driver bit held by the chuck portion. Electric screwdriver.

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