Agreement tools

Abstract

To provide a fastening tool configured so that fastening-depths of a screw fastened to an object to be fastened become constant, regardless of variation of amounts of engagement of a driver bit with the screw.SOLUTION: A fastening tool 1 comprises: a bit rotating motor 40 that rotates a driver bit; a detecting part 112 that detects a state of the bit rotating motor 40; and a control part 100 that stops rotation of the bit rotating motor 40 when determining that engagement of the driver bit with a screw is released, on the basis of the state of the bit rotating motor 40 detected by the detecting part 112.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a fastening tool that engages a driver bit with a screw, presses the screw with the driver bit against a fastening object, and rotates the driver bit to screw it in.

Background Art

[0002] There is known a tool called a portable driving machine that uses the air pressure of compressed air supplied from an air compressor or the combustion pressure of gas to sequentially drive out the connecting fasteners loaded in a magazine from the tip of a driver guide.

[0003] Conventionally, there has been proposed a pneumatic screw driving machine that rotates a bit with an air motor and moves it in the direction of driving the screw with air pressure in a tool that rotates a bit to tighten a screw and moves the bit in the direction of driving the screw (see, for example, Patent Document 1).

[0004] Also, there has been proposed a screw driving machine that compresses a spring with the driving force of a motor that rotates a driver bit and moves the driver bit axially by the biasing force of the spring to drive a screw (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] When a screwdriver bit is engaged with a screw recess and the screw is tightened by rotating the screwdriver bit, the screw recess and the tip of the screwdriver bit make contact at an angle. As a result, a portion of the rotational torque that rotates the screwdriver bit becomes a force that lifts the screwdriver bit away from the screw. Therefore, the degree of engagement between the screwdriver bit and the screw recess may vary depending on the strength of the force applied to press the screwdriver toward the object being fastened.

[0007] As described above, variations in the engagement between the driver bit and the screw recess can result in inconsistent screw tightening depths, leading to unstable finishes, such as the screw head being embedded in the object being fastened.

[0008] The present invention aims to solve these problems by providing a fastening tool that ensures a constant tightening depth of a screw when it is fastened into an object, regardless of variations in the amount of engagement between the driver bit and the screw. [Means for solving the problem]

[0009] To solve the above-mentioned problems, the present invention provides a bit holder that holds a screwdriver bit that can engage with a screw, and is rotatable in the circumferential direction and movable in the axial direction of the screwdriver bit, a first drive unit having a motor for rotating the bit holder, a control unit for controlling the motor, a detection unit for detecting the state of the motor, a second drive unit for moving the bit holder in the axial direction, and the axial direction of the bit holder moved by the second drive unit. place A position detection unit that detects placement and , an injection passage through which the driver bit passes, and a contact member that is pressed against the object to be fastened Equipped with, The position detection unit detects the axial position of the bit holder from the amount of movement of the driver bit, which is located in the standby position in the injection passage, from the standby position. The control unit is configured to allow a stop judgment tolerance position that allows detection of the disengagement of the driver bit from the screw. With the contact member pressed against the object to be fastened, the bit holder moves axially by the second drive unit, and the driver bit moves axially. When fastening a screw engaged with the driver bit to the object to be fastened, the bit holding part detected by the position detection unit placeThis fastening tool, after the motor has moved to a set stop-determination-allowable position, determines whether the engagement between the driver bit and the screw has been disengaged based on the motor state detected by the detection unit, and stops the rotation of the motor when it determines that the engagement between the driver bit and the screw has been disengaged. Furthermore, the present invention includes a bit holder that holds a screwdriver bit that can engage with a screw, and is rotatable in the circumferential direction and movable in the axial direction of the screwdriver bit, and a motor that rotates the bit holder. First drive unit having The system includes a control unit that controls the motor, and a detection unit that detects the motor's state and rotation amount. a second drive unit that moves the bit holding unit in the axial direction, and a contact member that is pressed against the object to be fastened The control unit is equipped with, With the contact member pressed against the object to be fastened, the bit holder moves axially by the second drive unit, and the driver bit moves axially. When fastening a screw engaged with the driver bit to an object, the amount of motor rotation detected by the detection unit determines when the engagement between the driver bit and the screw is released. Beyond the rotational speed at which cam-out cannot occur, This fastening tool determines whether the rotational speed has reached the permissible stopping speed at which cam-out detection is permitted. When the rotational speed reaches the permissible stopping speed, it determines whether the engagement between the driver bit and the screw has been disengaged based on the motor state detected by the detection unit. If it determines that the engagement between the driver bit and the screw has been disengaged, it stops the rotation of the motor.

[0010] In this invention, when it is determined that the engagement between the driver bit and the screw has been disengaged, it is determined that the screw has been tightened into the object to be fastened until the screw head is flush with the surface, and the rotation of the motor that rotates the driver bit is stopped. [Effects of the Invention]

[0011] In this invention, even if there is variation in the amount of engagement between the driver bit and the screw, the motor rotation can be stopped at the moment the screw is tightened into the object to be fastened until the screw head is flush with the surface. [Brief explanation of the drawing]

[0012] [Figure 1A] This is a side cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 1B] This is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 1C]It is an exploded perspective view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 2A] It is a perspective view showing an example of the main part configuration of the fastening tool of the present embodiment. [Figure 2B] It is a perspective view showing an example of the main part configuration of the fastening tool of the present embodiment. [Figure 3A] It is a cross-sectional perspective view showing an example of the main part configuration of the fastening tool of the present embodiment. [Figure 3B] It is a cross-sectional perspective view showing an example of the main part configuration of the fastening tool of the present embodiment. [Figure 4] It is a perspective view showing an example of the screw feed part and the nose part of the present embodiment. [Figure 5] It is a block diagram showing an example of the fastening tool of the present embodiment. [Figure 6] It is a perspective view showing an example of the setting part. [Figure 7] It is a flowchart showing an example of the operation of the fastening tool of the present embodiment. [Figure 8A] It is a cross-sectional view showing the fastening state of the screw. [Figure 8B] It is a cross-sectional view showing the fastening state of the screw. [Figure 8C] It is a cross-sectional view showing the fastening state of the screw. [Figure 9A] It is a graph showing the relationship between the rotational speeds of the bit rotation motor and the bit movement motor. [Figure 9B] It is a graph showing the current change of the bit rotation motor. [Figure 10] It is a flowchart showing another example of the operation of the fastening tool of the present embodiment. [Figure 11] It is a flowchart showing another example of the operation of the fastening tool of the present embodiment. [Figure 12A] It is a cross-sectional view showing the fastening state of the screw. [Figure 12B] It is a cross-sectional view showing the fastening state of the screw.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the fastening tool of the present invention will be described with reference to the drawings.

[0014] <Example of fastening tool configuration in this embodiment> Figure 1A is a side cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, Figure 1B is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, and Figure 1C is an exploded perspective view showing an example of the internal structure of the fastening tool of this embodiment.

[0015] The fastening tool 1 of this embodiment includes a bit holding unit 3 that holds a driver bit 2 that can engage with a screw 200 so that it can be rotatably and axially movable, a first drive unit 4 that rotates the driver bit 2 held by the bit holding unit 3, and a second drive unit 5 that moves the driver bit 2 held by the bit holding unit 3 in the axial direction.

[0016] The fastening tool 1 also includes a screw storage section 6 in which the screws 200 are stored, a screw feeding section 7 (described later) that feeds the screws stored in the screw storage section 6, and a nose section 8 that is pressed against the object to be fastened and from which the screws 200 are ejected.

[0017] Furthermore, the fastening tool 1 comprises a tool body 10 and a handle 11. The fastening tool 1 also includes a battery mounting section 13 at the end of the handle 11, to which a battery 12 can be detachably attached.

[0018] The fastening tool 1 has a tool body 10 that extends in one direction along the axial direction of the driver bit 2 indicated by arrows A1 and A2, and a handle 11 that extends in another direction intersecting the extension direction of the tool body 10. The direction in which the tool body 10 extends, i.e., the axial direction of the driver bit 2 indicated by arrows A1 and A2, is the front-back direction. The direction in which the handle 11 extends is the up-down direction. Furthermore, the direction perpendicular to the extension direction of the tool body 10 and the extension direction of the handle 11 is the left-right direction.

[0019] The first drive unit 4 is located at the rear of the tool body 10, on either side of the handle 11. The second drive unit 5 is located at the front of the tool body 10, on the other side of the handle 11.

[0020] The screw storage section 6 houses multiple screws 200 connected by connecting bands, forming spiral-wound connecting screws.

[0021] Figures 2A and 2B are perspective views showing an example of the main components of the fastening tool of this embodiment, and Figures 3A and 3B are cross-sectional perspective views showing an example of the main components of the fastening tool of this embodiment. Next, the bit holding unit 3 and the first drive unit 4 will be described with reference to each of these figures.

[0022] The bit holding unit 3 includes a holding member 30 that detachably holds the driver bit 2, a rotating guide member 31 that supports the holding member 30 so as to be movable in the front-rear direction indicated by arrows A1 and A2 along the axial direction of the driver bit 2 and rotates together with the holding member 30, a moving member 32 that moves the holding member 30 in the front-rear direction along the rotating guide member 31, and a biasing member 33 that biases the moving member 32 in the rearward direction indicated by arrow A2.

[0023] The retaining member 30 is composed of a cylindrical member, for example, whose outer diameter is slightly smaller than the inner diameter of the rotating guide member 31 and which is placed inside the rotating guide member 31. The retaining member 30 has an opening 30a at the front end of the driver bit 2 along its axial direction, which matches the cross-sectional shape of the driver bit 2. The retaining member 30 is equipped with a detachable retaining mechanism 30c in the opening 30a for detachably holding the driver bit 2. The opening 30a of the retaining member 30 is exposed to the inside of the rotating guide member 31, and the driver bit 2 is detachably inserted into the opening 30a.

[0024] The attachment / detachment holding mechanism 30c includes a ball 30d exposed within the opening 30a and a spring 30e that biases the ball 30d in the direction of being exposed within the opening 30a. The spring 30e is made of an annular leaf spring and is fitted around the outer circumference of the holding member 30.

[0025] The attachment and detachment holding mechanism 30c prevents the driver bit 2 from unintentionally coming out of the holding member 30 by having a ball 30d biased by a spring 30e fit into the groove of the driver bit 2. Furthermore, if a force greater than a predetermined amount is applied in the direction of removing the driver bit 2 from the holding member 30, the ball 30d retracts while the annular spring 30e deforms, making it possible to remove the driver bit 2 from the holding member 30.

[0026] The rotating guide member 31 extends along the extension direction of the tool body 10, that is, along the front-to-back direction indicated by arrows A1 and A2 along the axial direction of the driver bit 2. The rotating guide member 31 is cylindrical in shape with a retaining member 30 inside, and its front end is rotatably supported by a front frame 10b provided on the front side of the case 10a that constitutes the exterior of the tool body 10, via a bearing 34a, which is an example of a bearing. The rear end of the rotating guide member 31 is connected to the first drive unit 4.

[0027] The rotating guide member 31 has grooves 31a formed at two locations on its radially opposing circumferential surface, extending in the front-rear direction as indicated by arrows A1 and A2 along the axial direction of the driver bit 2. The rotating guide member 31 penetrates the holding member 30 radially, and connecting members 30b protruding from both sides of the holding member 30 enter the grooves 31a, thereby connecting the rotating guide member 31 to the holding member 30 via the connecting members 30b.

[0028] The connecting member 30b is a cylindrical member with an oval cross-section, and its longitudinal direction is aligned with the extension direction of the groove 31a, which is parallel to the axial direction of the driver bit 2 indicated by arrows A1 and A2. The transverse direction of the oval shape of the connecting member 30b is perpendicular to the extension direction of the groove 31a indicated by arrows B1 and B2, that is, aligned with the rotation direction of the rotating guide member 31. Furthermore, the width of the connecting member 30b in the transverse direction, that is, the width along the rotation direction of the rotating guide member 31, is configured to be slightly smaller than the width of the groove 31a along the same direction.

[0029] As a result, the connecting member 30b, which is placed in the groove 31a, is supported in the groove 31a so as to be movable along the axial direction of the rotating guide member 31. Furthermore, the movement of the connecting member 30b along the rotational direction relative to the rotating guide member 31 is restricted between one side and the other side of the groove 31a along the direction in which the groove 31a extends. Therefore, as the rotating guide member 31 rotates, the connecting member 30b is pushed against one side or the other side of the groove 31a depending on the rotational direction of the rotating guide member 31, and receives a circumferential force from the rotating guide member 31 that is in the rotational direction.

[0030] Therefore, when the rotating guide member 31 rotates, the connecting member 30b of the holding member 30 is pushed into the groove 31a of the rotating guide member 31, causing the holding member 30 to rotate together with the rotating guide member 31. In addition, the holding member 30 moves in the front-rear direction along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove 31a of the rotating guide member 31.

[0031] The movable member 32 includes a first movable member 32a that rotates together with the holding member 30 and moves the holding member 30 in the front-rear direction along the rotation guide member 31, a second movable member 32c that is supported by the first movable member 32a via a bearing 32b and pushes the first movable member 32a via the bearing 32b, and a cushioning member 32d attached to the rear side of the second movable member 32c.

[0032] The first movable member 32a is composed of, for example, a cylindrical member whose inner diameter is slightly larger than the outer diameter of the rotating guide member 31 and which is placed outside the rotating guide member 31. The first movable member 32a is connected to the holding member 30 via a connecting member 30b that protrudes from the groove 31a of the rotating guide member 31, thereby being supported so as to be movable along the axial direction of the rotating guide member 31.

[0033] The bearing 32b is an example of a bearing, inserted between the outer circumference of the first moving member 32a and the inner circumference of the second moving member 32c. The first moving member 32a constitutes a bearing inner ring retaining member that holds the inner ring of the bearing 32b, and the second moving member 32c constitutes a bearing outer ring retaining member that holds the outer ring of the bearing 32b. In the bearing 32b, the inner ring is supported on the outer circumference of the first moving member 32a so as to be unable to move in the rotational and axial directions, and the outer ring is supported on the inner circumference of the second moving member 32c so as to be unable to move in the rotational and axial directions.

[0034] As a result, the second movable member 32c is connected to the first movable member 32a via the bearing 32b, with its movement in the forward and backward direction along the axial direction restricted. The second movable member 32c also rotatably supports the first movable member 32a via the bearing 32b.

[0035] Therefore, the first moving member 32a is pushed by the second moving member 32c via the bearing 32b when the second moving member 32c moves in the forward and backward direction along the axial direction, and moves together with the second moving member 32c in the forward and backward direction along the axial direction. In addition, the first moving member 32a is rotatable relative to the second moving member 32c, which does not rotate relative to the rotating guide member 31.

[0036] In this example, the biasing member 33 is composed of a coil spring and is placed outside the rotating guide member 31, between the front frame 10b, which is provided on the front side of the case 10a of the tool body 10, and the second moving member 32c of the moving member 32, and contacts a spring seat 32f which is positioned to contact the end face of the outer ring of the bearing 32b. The biasing member 33 is compressed when the moving member 32 moves in the forward direction indicated by arrow A1, and applies a force to the moving member 32 that pushes it in the backward direction indicated by arrow A2.

[0037] The first drive unit 4 includes a bit rotation motor 40 and a reduction gear 41, which are driven by electricity supplied from the battery 12. The bit rotation motor 40 is a motor, an example of a first motor, in which the shaft 40a of the bit rotation motor 40 is connected to the reduction gear 41, and the shaft 41a of the reduction gear 41 is connected to the rotation guide member 31. In the first drive unit 4, the reduction gear 41 is configured to use planetary gears, and the bit rotation motor 40 is arranged coaxially with the rotation guide member 31 and the holding member 30, and the driver bit 2 held by the holding member 30.

[0038] The first drive unit 4 has a bit rotation motor 40 and a reduction gear 41 mounted on a rear frame 10c provided on the rear side of the case 10a of the tool body 10, and the shaft 41a of the reduction gear 41 is supported on the rear frame 10c via a bearing 42. The rear end of the rotation guide member 31 is connected to the shaft 41a of the reduction gear 41, and the shaft 41a is supported on the rear frame 10c via a bearing 42, so that it is rotatably supported via the bearing 42, which is an example of a bearing.

[0039] The bit holder 3 and the first drive unit 4 are assembled as a single unit by connecting the front frame 10b and the rear frame 10c with a connecting member 10d that extends in the front-rear direction, and the front frame 10b is fixed to the case 10a of the tool body 10 with screws 10e.

[0040] Furthermore, the bit holder 3 is supported by a bearing 34a at the front end of the rotating guide member 31, which is fixed to the front of the case 10a of the tool body 10, and by a shaft 41a and bearing 42 of the reduction gear 41 at the rear end of the rotating guide member 31, which is fixed to the rear of the case 10a. Thus, the bit holder 3 is rotatably supported by the rotating guide member 31 on the tool body 10.

[0041] As a result, the first drive unit 4 rotates the rotating guide member 31 using the bit rotation motor 40. The holding member 30, which holds the driver bit 2, rotates together with the rotating guide member 31 as the connecting member 30b is pressed against the groove 31a of the rotating guide member 31.

[0042] The bit holder 3 is provided with a guide member 32g on the second movable member 32c. The second movable member 32c is movable in the forward and backward directions indicated by arrows A1 and A2 along the axial direction of the driver bit 2, as the guide member 32g is guided by the coupling member 10d, and its rotation following the rotation guide member 31 is restricted.

[0043] Next, the second drive unit 5 will be described with reference to the figures. The second drive unit 5 comprises a bit moving motor 50 and a reduction gear 51, which are powered by electricity supplied from the battery 12. The bit moving motor 50 is an example of a second motor, and the shaft 50a of the bit moving motor 50 is connected to the reduction gear 51, and the shaft 51a of the reduction gear 51 is connected to a pulley 52, which is an example of a transmission member. In the second drive unit 5, the pulley 52 is supported on the tool body 10 via a bearing 53. In the second drive unit 5, the shaft 50a of the bit moving motor 50 is positioned along the extension direction of the handle 11.

[0044] The second drive unit 5 has one end of a linear wire 54, which is an example of a transmission member, connected to a pulley 52, and as the pulley 52 rotates, the wire 54 is wound around the pulley 52. ​​The other end of the wire 54 is connected to a wire connection part 32h provided on the second moving member 32c of the moving member 32.

[0045] As a result, the second drive unit 5 rotates the pulley 52 with the bit moving motor 50 and winds up the wire 54, thereby moving the second moving member 32c in the forward direction indicated by arrow A1. When the second moving member 32c moves forward, the first moving member 32a is pushed via the bearing 32b, and the first moving member 32a moves forward along the axial direction together with the second moving member 32c. When the first moving member 32a moves forward, the holding member 30, which is connected to the first moving member 32a via the connecting member 30b, moves forward, and the driver bit 2 held by the holding member 30 moves forward as indicated by arrow A1.

[0046] Therefore, by controlling the rotation amount of the bit movement motor 50, the amount of movement of the driver bit 2 attached to the holding member 30 can be controlled. In addition, by controlling the rotation speed of the bit movement motor 50, the movement speed of the driver bit 2 can be controlled.

[0047] Furthermore, since the wire 54 is flexible enough to be wound onto the pulley 52, it cannot push the second moving member 32c to move the moving member 32 backward. Therefore, a biasing member 33 is provided that compresses the moving member 32 when it moves forward as indicated by arrow A1, and applies a force to the moving member 32 that pushes it backward as indicated by arrow A2. In this configuration, the wire 54 is wound onto the pulley 52, and the driver bit 2 is advanced, and then the driver bit 2 can be moved backward after it has advanced.

[0048] Figure 4 is a perspective view showing an example of the screw feed section and nose section of this embodiment. Next, the screw feed section 7 and nose section 8 will be described with reference to each figure. The screw feed section 7 comprises a screw feed motor 70, a pinion gear 71 attached to the shaft of the screw feed motor 70 via a reduction gear, a rack gear 72 that meshes with the pinion gear 71, and an engagement section 73 that is connected to the rack gear 72 and engages with a connecting screw fed from the screw storage section 6.

[0049] In the screw feeding section 7, a rack gear 72 is supported so as to be movable in the vertical direction along the feeding direction of the connecting screw. In the screw feeding section 7, the screw feeding motor 70 rotates in forward and reverse directions, causing the engaging portion 73 that engages with the connecting screw to reciprocate in the vertical direction, thereby feeding the connecting screw. Alternatively, the screw feeding section 7 may be configured to reciprocate the engaging portion 73 by a drive unit that moves linearly using a combination of electromagnetic force and biasing means, such as a solenoid.

[0050] The nose section 8 is supplied with a screw 200 by the screw feeding section 7 and has an injection passage 80 through which the driver bit 2 passes. The nose section 8 also has an injection port 81a that communicates with the injection passage 80 and includes a contact member 81 that contacts the object to be fastened. Furthermore, the nose section 8 includes a contact arm 82 that moves in the front-rear direction in conjunction with the contact member 81.

[0051] In the nose section 8, the contact member 81 is supported so as to be movable in the front-rear direction indicated by arrows A1 and A2, and the contact arm 82 moves in the front-rear direction in conjunction with the contact member 81. In the nose section 8, the contact member 81 is biased forward by a biasing member (not shown), and the contact member 81, which has moved backward when pressed against the object to be fastened, is then biased forward by the biasing member and moves forward.

[0052] The fastening tool 1 includes a contact switch unit 84 that is activated when pressed by a contact arm 82. The contact switch unit 84 is activated or deactivated when pressed by the contact arm 82, depending on the position of the contact arm 82 as it moves backward when the contact member 81 is pressed against the object to be fastened. In this example, the state in which the contact switch unit 84 is not activated because it is not being pressed by the contact arm 82 is defined as the contact switch unit 84 being off, and the state in which the contact switch unit 84 is activated because it is being pressed by the contact arm 82 is defined as the contact switch unit 84 being on.

[0053] Figure 5 is a block diagram showing an example of a fastening tool according to this embodiment. Next, the configuration of the control and operation of the fastening tool 1 will be described with reference to each figure.

[0054] The fastening tool 1 includes a trigger 9 that receives input and a trigger switch 90 that operates when the trigger 9 is operated. As shown in Figure 1A, the trigger 9 is located on the front side of the handle 11 and is configured to be operable with the fingers of the hand gripping the handle 11. The trigger switch 90 operates when pressed by the trigger 9.

[0055] The trigger switch unit 90 is switched on or off when pressed by the trigger 9. In this example, when the trigger 9 is not operated and the trigger switch unit 90 is not pressed by the trigger 9, the trigger switch unit 90 is considered off, and when the trigger 9 is operated and the trigger switch unit 90 is activated by being pressed by the trigger 9, the trigger switch unit 90 is considered on.

[0056] The fastening tool 1 includes a control unit 100 that controls a first drive unit 4, a second drive unit 5, and a screw feed unit 7 based on the output of a trigger switch unit 90 that is operated by the operation of a trigger 9 and a contact switch unit 84 that is operated by being pressed by a contact member 81. The control unit 100 is made up of a circuit board on which various electronic components are mounted, and as shown in Figure 1A, it is housed in a circuit board housing unit 111 provided on the back side of the screw storage unit 6, between the screw storage unit 6 and the handle 11.

[0057] The control unit 100 controls whether the bit moving motor 50 of the second drive unit 5 and the bit rotating motor 40 of the first drive unit 4 are driven, based on the combination of the on / off states of the contact switch unit 84 and the trigger switch unit 90.

[0058] As described above, the fastening tool 1 includes a first drive unit 4 that rotates the driver bit 2, which is held by the holding member 30 in the bit holding unit 3, by the drive of the bit rotation motor 40. The fastening tool 1 also includes a second drive unit 5 that moves the driver bit 2, which is held by the holding member 30 in the bit holding unit 3, in the forward and backward directions along the axial direction by the drive of the bit movement motor 50.

[0059] In the fastening tool 1, the bit movement motor 50 rotates in a predetermined direction, causing the driver bit 2, held by the holding member 30 in the bit holding section 3, to move forward (advance) in the direction indicated by arrow A1. Also, in the fastening tool 1, the bit rotation motor 40 rotates in a predetermined direction, causing the driver bit 2 to rotate in the direction for fastening the screw 200.

[0060] The fastening tool 1 advances the driver bit 2 by rotating the bit moving motor 50, engaging the driver bit 2 with the recess of the screw 200, moving the screw 200 forward and pressing it against the object to be fastened.

[0061] Furthermore, the fastening tool 1 fastens the screw 200, which is engaged with the driver bit 2, to the object to be fastened by rotating the driver bit 2 in the direction of fastening the screw 200 using the rotation of the bit rotation motor 40.

[0062] Furthermore, the fastening tool 1 rotates the bit moving motor 50 in conjunction with the rotation of the bit rotating motor 40, thereby advancing the driver bit 2 in accordance with the fastening of the screw 200.

[0063] Therefore, the control unit 100 controls the amount of movement (advance movement) of the driver bit 2 by controlling the amount of rotation of the bit movement motor 50. By controlling the amount of movement of the driver bit 2, the control unit 100 controls the stopping position of the driver bit 2 along its axial direction.

[0064] Furthermore, the control unit 100 advances the driver bit 2 in accordance with the tightening of the screw 200 by controlling the rotation speed of the bit rotation motor 40 and the rotation speed of the bit movement motor 50.

[0065] Furthermore, the control unit 100 determines whether or not the driver bit 2 and the screw 200 are engaged based on the state of the bit rotation motor 40, and controls the timing for stopping the rotation of the bit rotation motor 40.

[0066] Therefore, the fastening tool 1 includes a detection unit 112 that detects the state of the bit rotation motor 40, which determines whether or not the engagement between the driver bit 2 and the screw 200 has been disengaged by the operation of rotating the bit rotation motor 40.

[0067] The detection unit 112 detects whether the load on the bit rotation motor 40 is equivalent to the load that causes the driver bit 2 and screw 200 to disengage. To this end, the detection unit 112 detects the current value, rotational speed, or voltage value of the bit rotation motor 40. For example, the detection unit 112 detects whether the load on the bit rotation motor 40 is equivalent to the load that causes the driver bit 2 and screw 200 to disengage, based on the current value flowing through the bit rotation motor 40, or the motor applied voltage value which changes depending on the current flowing through the bit rotation motor 40. Alternatively, the detection unit 112 may also detect whether the load on the bit rotation motor 40 is equivalent to the load that causes the driver bit 2 and screw 200 to disengage, based on the rotational speed of the bit rotation motor 40. Note that the function of the detection unit 112 may also be implemented by the control unit 100. Alternatively, the detection unit 112 may detect the amount of rotation of the bit rotation motor 40, and the control unit 100 may determine whether or not the engagement between the driver bit 2 and the screw 200 has been released based on the amount of rotation of the bit rotation motor 40 detected by the detection unit 112. Furthermore, the detection unit 112 may detect the rotation time of the bit rotation motor 40, and the control unit 100 may determine whether or not the engagement between the driver bit 2 and the screw 200 has been released based on the rotation time of the bit rotation motor 40 detected by the detection unit 112.

[0068] The control unit 100 rotates the bit rotation motor 40 in the direction of fastening the screw 200, which is engaged with the driver bit 2 held by the holding member 30 in the bit holding unit 3, to the object to be fastened. Based on the state of the bit rotation motor 40 detected by the detection unit 112, if it determines that the engagement between the driver bit 2 and the screw 200 has been released, it stops the rotation of the bit rotation motor 40.

[0069] Furthermore, the control unit 100 controls the axial position of the bit holding unit 3 with the amount of rotation of the bit moving motor 50. When it determines that the bit holding unit 3 has moved to a stop judgment allowable position that allows detection of disengagement between the driver bit 2 and the screw 200, it determines whether or not disengagement between the driver bit 2 and the screw 200 has occurred based on the state of the bit rotating motor 40 detected by the detection unit 112.

[0070] Therefore, the fastening tool 1 is equipped with a position detection unit 113 that detects the axial movement position of the driver bit 2 (the movement position of the holding member 30). The position detection unit 113, for example, detects the amount of rotation of the bit movement motor 50 and detects the position of the driver bit 2 (the position of the holding member 30) based on the amount of rotation of the bit movement motor 50. The control unit 100 determines whether the driver bit 2 (holding member 30) has moved to a predetermined stop judgment allowable position (forward end position) based on the position of the driver bit 2 (the position of the holding member 30) detected by the position detection unit 113. Note that the function of the position detection unit 113 may also be implemented by the control unit 100.

[0071] As a result, if the engagement between the driver bit 2 and the screw 200 becomes disengaged while the screw 200 is being fastened to the object, the detection unit 112 will detect the state of the bit rotation motor 40 and prevent the rotation of the bit rotation motor 40 from being stopped.

[0072] The fastening tool 1 includes a setting unit 110 in which the rotation amount of the bit moving motor 50 that defines the forward movement amount of the driver bit 2 is set. Figure 6 is a perspective view showing an example of the setting unit, and the setting unit 110 will now be described with reference to each figure.

[0073] The setting unit 110 is an example of a setting means, and is configured to allow selection of any setting value from a plurality of setting values, or to allow stepless selection of any setting value.

[0074] In this example, the setting unit 110 is configured such that the setting value is selected by an operation unit 110a consisting of buttons. Alternatively, the operation unit 110a may be configured such that the setting value is selected by a rotary dial. Furthermore, the setting unit 110 may be configured to display the selected setting value so that the operator can easily understand the current setting value, for example by indicating the current value with a label or engraving, or by indicating the current value with a display unit 110b such as an LED. The contents displayed on the display unit 110b include the setting value of the screw depth defined by the amount the driver bit 2 advances, the ON / OFF status of the power, the operating mode selected from the various selectable operating modes, the presence or absence of screws, the remaining amount of screws, and whether or not there is a problem.

[0075] The setting section 110 is provided on both the left and right sides of the surface facing the handle 11 in the circuit board storage section 111, which is located on the back side of the screw storage section 6.

[0076] This makes it possible to see the setting section 110 from both the left and right sides of the handle 11 when viewing the fastening tool 1 from the rear.

[0077] <Example of operation of the fastening tool in this embodiment> Figure 7 is a flowchart showing an example of the operation of the fastening tool of this embodiment, Figures 8A, 8B, and 8C are cross-sectional views showing the screw fastening state, Figure 9A is a graph showing the relationship between the rotational speeds of the bit rotation motor and the bit movement motor, and Figure 9B is a graph showing the current change of the bit rotation motor. Next, the fastening operation of the fastening tool of this embodiment will be described with reference to each figure.

[0078] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0079] In step SA1 of Figure 7, the control unit 100 sets the rotation amount of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened 202, and the contact switch unit 84 is pressed by the contact arm 82, the contact switch unit 84 turns ON in step SA2, the trigger 9 is operated, and the trigger switch unit 90 turns ON in step SA3, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SA4, and drives the bit movement motor 50 of the second drive unit 5 in step SA5.

[0080] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52. ​​As the wire 54 is wound onto the pulley 52, the second moving member 32c, which is connected to the wire 54, is guided by the rotating guide member 31 and moves forward along the axial direction. As the second moving member 32c moves forward, the first moving member 32a is pushed by the second moving member 32c via the bearing 32b, and together with the second moving member 32c, it moves forward along the axial direction while compressing the biasing member 33.

[0081] When the first movable member 32a moves forward, the holding member 30, which is connected to the first movable member 32a by the connecting member 30b, moves forward along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove 31a of the rotating guide member 31.

[0082] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened 202.

[0083] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, the rotation guide member 31 rotates in the positive direction. When the rotation guide member 31 rotates in the positive direction, the connecting member 30b, which is connected to the holding member 30, is pressed against the groove 31a of the rotation guide member 31, causing the holding member 30 to rotate together with the rotation guide member 31.

[0084] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction (clockwise) and tightens it into the object to be fastened 202. When the fastening tool 1 starts the operation of rotating the driver bit 2 to tighten the screw 200 into the object to be fastened, a load is generated on the driver bit 2 via the screw 200. After the timing T1 when the load is generated by tightening the screw, both the rotation speed V1 of the bit rotation motor 40 and the rotation speed V2 of the bit movement motor 50 decrease.

[0085] In step SA6, the control unit 100 determines that the rotation amount of the bit movement motor 50 has reached the set value selected by the setting unit 110, and that at timing T2, as shown in Figures 8A and 8B, the tip of the driver bit 2 has reached the set forward end position P2, and in step SA7, it stops the rotation of the bit movement motor 50 in the forward direction.

[0086] If the contact switch unit 84 is ON in step SA8, the control unit 100 continues to rotate the bit rotation motor 40 in the forward direction. After stopping the rotation of the bit movement motor 50, the control unit 100 determines in step SA9, based on the state of the bit rotation motor 40 detected by the detection unit 112, whether the engagement between the screw 200 and the driver bit 2, which is held in the bit holding unit 3 and rotated by the bit rotation motor 40, has been disengaged.

[0087] The control unit 100 rotates the bit rotation motor 40 in the direction of fastening the screw 200, which is engaged with the driver bit 2 held by the holding member 30 in the bit holding unit 3, to the object to be fastened 202. Based on the state of the bit rotation motor 40 detected by the detection unit 112, if it determines that the engagement between the driver bit 2 and the screw 200 has been released, it stops driving the bit rotation motor 40 in step SA10, and then reverses the bit movement motor 50 in step SA11.

[0088] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, causing the wire 54 to be pulled out from the pulley 52. ​​As the wire 54 is pulled out from the pulley 52, the second moving member 32c moves forward, causing the compressed biasing member 33 to expand and push the second moving member 32c backward.

[0089] The second moving member 32c is pushed backward by the biasing member 33, guided by the rotating guide member 31, and moves backward along the axial direction. As the second moving member 32c moves backward, the first moving member 32a is pulled by the second moving member 32c via the bearing 32b, and moves backward along the axial direction together with the second moving member 32c.

[0090] When the first movable member 32a moves in the rearward direction, the holding member 30, which is connected to the first movable member 32a by the connecting member 30b, moves in the rearward direction along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove 31a of the rotating guide member 31.

[0091] In step SA12, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SA13.

[0092] When the trigger switch unit 90 is turned off, the control unit 100 rotates the screw feed motor 70 in one direction to lower the engagement portion 73. When the engagement portion 73 has lowered to a position where it engages with the next screw 200, the control unit 100 reverses the screw feed motor 70 to raise the engagement portion 73 and supply the next screw 200 to the injection passage 80. Alternatively, before the trigger switch unit 90 is turned off, the engagement portion 73 may be lowered to a position where it engages with the next screw 200 and kept waiting while the screw 200 is being fastened. This shortens the time until the next screw 200 can be supplied to the injection passage 80.

[0093] When the driver bit 2 is engaged with the recess 200a of the screw 200 and the driver bit 2 is rotated to tighten the screw 200, the recess 200a of the screw 200 and the driver bit 2 make contact at an angle. As a result, a portion of the rotational torque becomes a force that lifts the driver bit 2 away from the screw 200. If the operator's pressing force in the direction of the fastening tool 1 toward the object to be fastened 202 is weak, the recess 200a of the screw 200 and the tip of the driver bit 2 may not make close contact.

[0094] Therefore, when fastening the screw 200 with the driver bit 2, there is a possibility that variations may occur in the amount of engagement between the driver bit 2 and the recess 200a of the screw 200.

[0095] Therefore, the position of the tip of the driver bit 2 where the head 201 of the screw 200 is lifted away from the object 202 to be fastened is defined as the forward end position P2. In this way, when the tip of the driver bit 2 reaches the forward end position P2, the forward rotation of the bit moving motor 50 stops, and after the forward movement of the driver bit 2 has finished, the head 201 of the screw 200 is still lifted away from the object 202 to be fastened, and by continuing the forward rotation of the bit rotating motor 40, the screw 200 is further tightened into the object 202 to be fastened.

[0096] When the screw 200 is tightened into the object 202 to the point where its head 201 is flush with the surface of the object 202, neither lifting up nor sinking in, a condition known as cam-out occurs, in which the engagement between the driver bit 2 and the recess 200a of the screw 200 is disengaged.

[0097] As a result, when the engagement between the driver bit 2 and the screw 200 is detected to have been disengaged, it can be determined that the screw 200 has been tightened into the object 202 until the head 201 of the screw 200 is flush with the surface.

[0098] As shown in Figures 8A and 8B, if there is variation in the engagement amounts L1 and L2 between the driver bit 2 and the recess 200a of the screw 200, the tightening depth of the screw 200 will not be consistent when the tip of the driver bit 2 reaches the forward end position P2.

[0099] In response, the control unit 100 rotates the bit rotation motor 40 after the tip of the driver bit 2 reaches the forward end position P2, until the engagement between the driver bit 2 and the screw 200 is released. Based on the state of the bit rotation motor 40 detected by the detection unit 112, if it determines that the engagement between the driver bit 2 and the screw 200 has been released, it stops driving the bit rotation motor 40.

[0100] As a result, the tightening depth of the screw 200 is determined at the point where the engagement between the driver bit 2 and the recess 200a of the screw 200 is disengaged, regardless of the amount of engagement between the driver bit 2 and the recess 200a of the screw 200. Therefore, as shown in Figure 8C, the rotation of the bit rotation motor 40 can be stopped at the moment the screw 200 is tightened into the object 202 to the point where the head 201 of the screw 200 is flush with the surface, allowing for precise control of the screw tightening depth.

[0101] The control unit 100 determines that the engagement between the driver bit 2 and the screw 200 has been released from a change in the rotational speed of the bit rotation motor 40, for example, detected by the detection unit 112. While the screw 200 is being tightened into the object 202, the bit rotation motor 40 is constantly under load, so as shown in Figure 9A, the rotational speed V1 of the bit rotation motor 40 gradually decreases. In contrast, when the engagement between the driver bit 2 and the screw 200 is released, the load on the bit rotation motor 40 decreases, causing the rotational speed to increase. Therefore, the control unit 100 determines that so-called cam-out has occurred by detecting the increase in the rotational speed of the bit rotation motor 40. For example, during the operation of rotating the bit rotation motor 40, the control unit 100 determines that the engagement between the driver bit 2 and the screw 200 has been released at timing T3 when the rotational speed of the bit rotation motor 40 increases. Furthermore, when the engagement between the driver bit 2 and the screw 200 is released, the driver bit 2 will spin freely (unloaded or nearly unloaded). Therefore, when the rotational speed of the bit rotation motor 40 becomes equivalent to the rotational speed of the driver bit 2 when it is spinning freely, it can be determined that the engagement between the driver bit 2 and the screw 200 has been released.

[0102] The disengagement of the driver bit 2 and the screw 200 can be determined by detecting changes in the current and voltage values ​​flowing through the bit rotation motor 40. When the driver bit 2 and the screw 200 are disengaged, the load on the bit rotation motor 40 decreases, causing the current flowing through the bit rotation motor 40 to decrease. Therefore, during the operation of rotating the bit rotation motor 40, the disengagement of the driver bit 2 and the screw 200 can be determined at timing T3, when the current flowing through the bit rotation motor 40 decreases, as shown in Figure 9B. Alternatively, when the driver bit 2 and the screw 200 are disengaged, the load on the bit rotation motor 40 decreases, causing the voltage applied to the bit rotation motor 40 to increase. Therefore, during the operation of rotating the bit rotation motor 40, the disengagement of the driver bit 2 and the screw 200 can be determined at the timing when the voltage applied to the bit rotation motor 40 increases. Furthermore, when the engagement between the driver bit 2 and the screw 200 is released, the driver bit 2 will spin freely (no load or near no load). Therefore, when the current and voltage flowing through the bit rotation motor 40 become equivalent to the current and voltage values ​​when the driver bit 2 is spinning freely, it can be determined that the engagement between the driver bit 2 and the screw 200 has been released.

[0103] Furthermore, if the bit rotation motor 40 continues to rotate while cam-out occurs, it can cause discomfort to the operator due to wear on the driver bit 2 and noise during cam-out. Therefore, it is desirable to detect cam-out quickly and stop the rotation of the bit rotation motor 40. Setting a small threshold for the amount of rotational speed increase required to detect cam-out allows for quick detection of cam-out. However, setting a small threshold for the amount of rotational speed increase increases the likelihood of false detections.

[0104] Therefore, false detections can be avoided by setting the timing for detecting cam-out. The timing for detecting cam-out can be set to, for example, after it is detected that the load on the bit rotation motor 40 exceeds the load required to tighten the screw 200, or after the driver bit 2 has advanced to a stop judgment allowable position that allows for cam-out detection, or when the contact switch unit 84 is ON. Any of these conditions can suppress the occurrence of false detections. The stop judgment allowable position may also be the forward end position P2. Furthermore, in addition to any of the above conditions, if the rotation amount of the bit rotation motor 40 is only an amount that does not cause cam-out, cam-out detection will be suppressed, and cam-out detection will be performed after it reaches a stop judgment allowable rotation amount that allows for cam-out detection. This further suppresses the occurrence of false detections.

[0105] Figure 10 is a flowchart showing another example of the operation of the fastening tool of this embodiment. The second drive unit 5, which moves the driver bit 2 held by the bit holding unit 3 in the axial direction, may move the driver bit (holding unit 30) in the axial direction by utilizing a force biased by a biasing member such as a spring, or by gas pressure. In a configuration in which the driver bit 2 (holding unit 30) is moved in the axial direction by utilizing a force biased by a biasing member, or by gas pressure, the amount of movement of the driver bit 2 (holding unit 30) may be defined by a mechanical configuration such as abutting the holding unit 30 against a positioning member, and control may be performed by considering that the driver bit 2 (holding unit 30) has moved to a predetermined forward end position. Alternatively, the driver bit 2 (holding unit 30) may be considered to have moved to a predetermined forward end position based on the elapsed time since the driver bit 2 (holding unit 30) started moving forward.

[0106] When the contact member 81 is pressed against the object to be fastened 202, the contact arm 82 presses the contact switch unit 84, turning the contact switch unit 84 ON in step SB1, and the trigger 9 is operated, turning the trigger switch unit 90 ON in step SB2, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SB3, and advances the driver bit 2 (holding member 30) in step SB4.

[0107] As a result, the driver bit 2 moves forward, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened 202.

[0108] Furthermore, when the bit rotation motor 40 is driven and rotates in the forward direction, which is one direction, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction and tightens it into the object to be fastened 202.

[0109] The control unit 100 determines that the tip of the driver bit 2 has reached the set forward end position P2, and terminates the forward movement of the driver bit 2 (holding member 30) in step SB5.

[0110] If the contact switch unit 84 is ON in step SB6, the control unit 100 continues to rotate the bit rotation motor 40 in the forward direction. In step SB7, the control unit 100 determines whether the engagement between the driver bit 2 and the screw 200 has been disengaged, based on the state of the bit rotation motor 40 detected by the detection unit 112.

[0111] Based on the state of the bit rotation motor 40 detected by the detection unit 112, if the control unit 100 determines that the engagement between the driver bit 2 and the screw 200 has been disengaged, it stops driving the bit rotation motor 40 in step SB8, and then returns the driver bit 2 to its initial position in step SB9.

[0112] This allows the rotation of the bit rotation motor 40 to be stopped when the screw 200 is tightened into the object 202 to the point where the head 201 of the screw 200 is flush with the surface, enabling precise control of the screw tightening depth.

[0113] Figure 11 is a flowchart showing another example of the operation of the fastening tool of this embodiment. The control to stop the bit rotation motor 40 may be performed based on a predetermined stop condition that deems the engagement between the driver bit 2 and the screw 200 to have been disengaged.

[0114] In step SC1 of Figure 11, the control unit 100 sets the rotation amount of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened 202, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 turns ON in step SC2, the trigger 9 is operated, and the trigger switch unit 90 turns ON in step SC3, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SC4, and drives the bit movement motor 50 of the second drive unit 5 in step SC5.

[0115] As a result, the driver bit 2 held by the retaining member 30 moves forward, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened 202.

[0116] Furthermore, when the bit rotation motor 40 is driven and rotates in the forward direction, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction (clockwise) and tightens it into the object 202 to be fastened.

[0117] In step SC6, the control unit 100 determines that the rotation amount of the bit movement motor 50 has reached the set value selected by the setting unit 110, and that the tip of the driver bit 2 has reached the set forward end position P2, and in step SC7, it stops the rotation of the bit movement motor 50 in the forward direction.

[0118] If the contact switch unit 84 is ON in step SC8, the control unit 100 continues to rotate the bit rotation motor 40 in the forward direction. After stopping the rotation of the bit movement motor 50, the control unit 100 determines in step SC9 whether the predetermined stop conditions for stopping the rotation of the bit rotation motor 40 have been met.

[0119] The control unit 100 determines that the amount of rotation of the bit rotation motor 40 has reached a predetermined amount corresponding to the disengagement of the driver bit 2 and the screw 200, and stops driving the bit rotation motor 40 in step SC10. Alternatively, the control unit 100 determines that the rotation time of the bit rotation motor 40 has reached a predetermined rotation time corresponding to the disengagement of the driver bit 2 and the screw 200, and stops driving the bit rotation motor 40 in step SC10. After stopping driving the bit rotation motor 40 in step SC10, the control unit 100 reverses the bit movement motor 50 in step SC11.

[0120] In step SC12, the control unit 100 reverses the bit movement motor 50 to a predetermined initial position, and when the holding member 30 and the moving member 32 move backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SC13.

[0121] When the tip of the driver bit 2 reaches the forward end position P2 and the forward rotation of the bit moving motor 50 stops, the forward movement of the driver bit 2 is complete. However, the head 201 of the screw 200 is still lifted away from the object to be fastened 202. By continuing the forward rotation of the bit rotating motor 40, the screw 200 is further tightened into the object to be fastened 202.

[0122] By further rotating the bit rotation motor 40 in the forward direction from a state where the head 201 of the screw 200 is lifted away from the object 202 to be fastened, the amount of rotation and rotation time required for the bit rotation motor 40 to disengage the engagement between the driver bit 2 and the screw 200 can be roughly estimated.

[0123] Therefore, when it is determined that the rotation amount of the bit rotation motor 40 has reached a specified amount of rotation equivalent to the disengagement of the driver bit 2 and the screw 200, the drive of the bit rotation motor 40 is stopped, and it can be determined that the screw 200 has been tightened into the object 202 to a state where the head 201 of the screw 200 is flush with the surface, without detecting that the engagement between the driver bit 2 and the screw 200 has been disengaged. Also, when it is determined that the rotation time of the bit rotation motor 40 has reached a specified rotation time equivalent to the disengagement of the driver bit 2 and the screw 200, the drive of the bit rotation motor 40 is stopped, and it can be determined that the screw 200 has been tightened into the object 202 to a state where the head 201 of the screw 200 is flush with the surface, without detecting that the engagement between the driver bit 2 and the screw 200 has been disengaged.

[0124] <Modified example of the fastening tool according to the embodiment> Figures 12A and 12B are cross-sectional views showing the fastening state of the screw, and next, a modified example of the fastening tool of this embodiment will be described with reference to each figure.

[0125] As shown in Figure 12A, the fastening tool 1 can perform the action of tightening the screw 200 into the surface of the object to be fastened 202 in a nearly perpendicular direction. In addition, when fastening in an inside corner (for example, a recessed corner formed by two perpendicular surfaces), where the fastening tool 1 cannot be applied perpendicularly to the object to be fastened 202, an action called oblique driving can be considered, as shown in Figure 12B, in which the screw 200 is tightened at an angle to the surface of the object to be fastened 202.

[0126] In the case of the fastening tool 1, when the screw 200 is driven in at an angle relative to the surface of the object to be fastened 202, a portion of the tip of the contact member 81 comes into contact with the object to be fastened 202, creating a gap L3 between the nozzle 81a of the nose portion 8 and the object to be fastened 202. Therefore, if the rotation of the bit movement motor 50 is stopped when the tip of the driver bit 2 reaches the forward end position P2, which is set to match the operation of driving the screw 200 in a direction approximately perpendicular to the surface of the object to be fastened 202, the amount of movement (forward movement) of the driver bit 2 may be insufficient.

[0127] Therefore, the forward end position P2 corresponding to the diagonal driving operation can be set using the setting unit 110. The forward end position P2 corresponding to the diagonal driving operation (also referred to as diagonal driving mode) can be selected by gradually increasing the amount of movement (forward movement) of the driver bit 2 through the operation of the setting unit 110.

[0128] In the angled driving mode, the forward end position P2 can be set by assigning one of the buttons on the operating unit 110a to this setting, so that the forward end position P2 can be switched each time the operating unit 110a is pressed. In the angled driving mode, the setting of the forward end position P2 is such that the rate of change of the amount of movement (forward movement) of the driver bit 2 is larger compared to when the forward end position P2 is finely adjusted. In addition, several types of forward end positions P2 may be selectable depending on the angle at which the screw 200 is tilted with respect to the surface of the object to be fastened 202. This makes it possible to set the forward end position P2 according to the angled driving mode quickly and easily compared to when the forward end position P2 is finely adjusted. [Explanation of Symbols]

[0129] 1... Fastening tool, 10... Tool body, 11... Handle, 2... Driver bit, 3... Bit holder, 30... Holding member, 31... Rotation guide member, 32... Moving member, 33... Biasing member, 4... First drive unit, 40... Bit rotation motor (motor, first motor), 5... Second drive unit, 50... Bit movement motor (second motor), 52... Pulley, 54... Wire, 6... Screw storage unit, 7... Screw feeding unit, 8... Nose unit, 81... Contact member, 84... Contact switch unit, 9... Trigger, 90... Trigger switch unit, 100... Control unit, 110... Setting unit, 112... Detection unit, 113... Position detection unit

Claims

1. A bit holder that holds a screwdriver bit that can engage with a screw, and is rotatable in the circumferential direction and movable in the axial direction of the screwdriver bit, A first drive unit having a motor for rotating the bit holding unit, A control unit for controlling the motor, A detection unit for detecting the state of the motor, A second drive unit moves the bit holding unit in the axial direction, A position detection unit that detects the axial position of the bit holder that moves by the second drive unit, The injection path through which the driver bit passes, The contact member that is pressed against the object to be fastened and Equipped with, The position detection unit detects the axial position of the bit holding unit from the amount of movement of the driver bit located at the standby position in the injection passage from the standby position. The control unit has a stop judgment tolerance position set that allows detection of disengagement between the driver bit and the screw. When the contact member is pressed against the object to be fastened, the bit holder is moved axially by the second drive unit, the driver bit moves axially, and the screw engaged with the driver bit is fastened to the object to be fastened. After the position of the bit holder detected by the position detection unit moves to the set stop judgment tolerance position, the control unit determines whether or not disengagement between the driver bit and the screw has occurred based on the state of the motor detected by the detection unit. If it is determined that disengagement between the driver bit and the screw has occurred, the control unit stops the rotation of the motor. Fastening tools.

2. The second drive unit comprises a bit movement motor and a transmission member that controls the amount of axial movement of the bit holding unit by controlling the amount of rotation of the bit movement motor. The position detection unit detects the amount of rotation of the bit movement motor and detects the position of the bit holder based on the amount of axial movement of the bit holder corresponding to the amount of rotation of the bit movement motor. The fastening tool according to claim 1.

3. The stop determination allowable position is the forward end position of the bit holding unit moved by the second drive unit. The fastening tool according to claim 1.

4. A bit holder that holds a screwdriver bit that can engage with a screw, and is rotatable in the circumferential direction and movable in the axial direction of the screwdriver bit, A first drive unit having a motor for rotating the bit holding unit, A control unit for controlling the motor, A detection unit for detecting the state and rotation amount of the motor, A second drive unit moves the bit holding unit in the axial direction, The contact member that is pressed against the object to be fastened and Equipped with, When the contact member is pressed against the object to be fastened, the control unit determines whether the amount of rotation of the motor detected by the detection unit has exceeded the amount of rotation at which cam-out, which causes the driver bit to disengage from the screw, has occurred, and whether the amount of rotation has reached the amount of rotation at which cam-out can be detected, and whether the amount of rotation has reached the amount of rotation at which cam-out can be detected. When the amount of rotation has reached the amount of rotation at which cam-out can be detected, the control unit determines whether the driver bit and the screw have disengaged based on the state of the motor detected by the detection unit, and when it is determined that the driver bit and the screw have disengaged, it stops the rotation of the motor. Fastening tools.

5. The detection unit detects the current value of the motor, The control unit determines, based on the detected current value, whether or not the screwdriver bit has become disengaged. A fastening tool according to any one of claims 1 to 4.

6. The detection unit detects the rotational speed of the motor, The control unit determines, based on the detected rotational speed, whether or not the engagement between the driver bit and the screw has been disengaged. A fastening tool according to any one of claims 1 to 4.

7. The detection unit detects the amount of rotation of the motor, and the control unit determines whether the engagement between the driver bit and the screw has been disengaged based on whether the detected amount of rotation has reached a specified amount of rotation corresponding to the disengagement of the driver bit and the screw. The fastening tool according to claim 3.

8. The detection unit detects the rotation time of the motor, The control unit determines, based on the detected rotation time, whether or not the screwdriver bit has disengaged from the screw. The fastening tool according to claim 3.

Images