CN214923930U - Screw fastening machine for gypsum board - Google Patents

Abstract

The utility model provides a screw fastening machine that gypsum board was used need not to adopt special screw or open the bottom outlet earlier, just can carry out the fastening operation of stereoplasm gypsum board. A screwdriver (1) is provided with: a brushless motor (11); a first spindle (41) that is rotated by a brushless motor (11); a second spindle (44) which can move in the direction of the rotation axis of the first spindle (41) in a direction approaching or separating from the first spindle (41); and a bit holding hole (60) that rotates integrally with the second main shaft (44), wherein the second main shaft (44) approaches the first main shaft (41), and the rotation of the first main shaft (41) can be transmitted to the second main shaft (44), so that the second main shaft (44) rotates in the forward direction and the screw can be fastened. When the gypsum board is fastened by screws, the hard board fastening mode can be used in which the second main shaft (44) rotates in the reverse direction once and then rotates in the normal direction.

Description

Screw fastening machine for gypsum board

Technical Field

The utility model relates to a screw fastening machine that gypsum boards such as screwdriver were used.

Background

As a screw fastening machine, patent document 1 discloses a screwdriver. The screwdriver includes a first main shaft and a second main shaft at an output portion of a tip. The rotation of the rotating shaft of the motor is transmitted to the first spindle. The second spindle is coaxially arranged in front of the first spindle so as to be movable forward and backward, and can hold the tool bit at the tip. The first main shaft and the second main shaft have cams on their facing surfaces, and the cams are engaged with each other at the retreated position of the second main shaft. The second main shaft is biased to an advanced position where the cams are separated from each other.

Screwdrivers are used in the fastening of plasterboards. If the trigger is pressed in a state that the cutter head is pressed on the screw standing on the gypsum board, the motor is driven so that the rotation of the rotating shaft is transmitted to the first main shaft. If the bit is continuously pressed against the screw, the second spindle is retracted, so that the cam of the first spindle engages with the cam of the second spindle. Thereby, the second main shaft rotates together with the first main shaft, and the screw can be screwed into the gypsum board. If the second spindle is further screwed in and advances, the cams are disengaged from each other, the rotation of the second spindle is stopped, and the fastening operation is completed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-187766

SUMMERY OF THE UTILITY MODEL

In the case of ordinary gypsum board, the gypsum board is fastened by pushing it apart and compressing it when it is screwed in. However, since the hard gypsum board has a high density, the gypsum pushed open by the screw during screwing rises on the surface of the gypsum board and deteriorates the processed surface. This causes a fastening operation using a dedicated screw or a fastening operation after a pilot hole is opened. The special screw is expensive, and the work takes labor and time if the bottomed hole is bored.

Therefore, an object of the present invention is to provide a screw fastening machine for gypsum board, which can fasten a hard gypsum board without using a special screw or opening a bottom hole first.

In order to achieve the above object, the present invention provides a screw fastening machine for gypsum boards, which comprises: a motor; a first member rotated by a motor; a second member movable in a direction approaching or separating from the first member in a direction of a rotation axis of the first member; and a bit holding portion that rotates integrally with the second member, wherein the screw fastening machine for gypsum board is configured such that: the screw fastening machine for gypsum board is characterized in that the screw fastening machine for gypsum board is configured such that the second member is capable of transmitting rotation of the first member to the second member by approaching the second member to the first member, and the second member is capable of rotating forward to fasten a screw: when fastening the gypsum board with a screw, the second member can be used in a fastening mode in which the second member is rotated in the reverse direction once and then rotated in the normal direction.

The first utility model discloses a another aspect on the basis of above-mentioned constitution, its characterized in that, the screw fastening mechanism for the gypsum board constitutes: the second member is reversed until a predetermined time elapses or the current value of the motor reaches a predetermined value.

The first utility model discloses a another aspect on the basis of above-mentioned constitution, its characterized in that, the screw fastening mechanism for the gypsum board constitutes: in the fastening mode, the rotation speed of the second member is reduced before the fastening of the screw is completed.

In order to achieve the above object, the utility model discloses in, the second utility model relates to a screw fastening machine that gypsum board was used, it possesses: a motor; a first member rotated by a motor; a second member movable in a direction approaching or separating from the first member in a direction of a rotation axis of the first member; and a bit holding portion that rotates integrally with the second member, wherein the screw fastening machine for gypsum board is configured such that: the screw fastening machine for gypsum board is characterized in that the screw fastening machine for gypsum board is configured such that the second member is capable of transmitting rotation of the first member to the second member by approaching the second member to the first member, and the second member is capable of rotating forward to fasten a screw: the first and second fastening modes can be selected for use when the first gypsum board is fastened by screws and when the second gypsum board made of a different material from the first gypsum board is fastened by screws.

In another aspect of the present invention, the second gypsum board is made of a harder material than the first gypsum board.

The second utility model discloses a on the basis of above-mentioned constitution, its characterized in that, the screw fastening mechanism for the gypsum board constitutes: the first fastening mode is a mode in which the second member always rotates forward, and the second fastening mode is a mode in which the second member rotates forward after temporarily rotating backward.

The second utility model discloses a on the basis of above-mentioned constitution, its characterized in that, the screw fastening mechanism for the gypsum board constitutes: in the second fastening mode, the rotation speed of the second member is reduced before the fastening of the screw is completed.

The second utility model discloses a on the basis of above-mentioned constitution, its characterized in that, the screw fastening mechanism for the gypsum board constitutes: the first fastening mode is a mode in which the second member performs normal rotation at a constant rotation speed until the fastening of the screw is completed, and the second fastening mode is a mode in which the second member performs normal rotation while changing the rotation speed at a predetermined timing.

The second utility model discloses a on the basis of above-mentioned constitution, its characterized in that, the screw fastening mechanism for the gypsum board constitutes: the rotation speed of the second member in the second fastening mode changes from low-speed rotation to high-speed rotation.

The utility model discloses a another scheme is on the basis of above-mentioned constitution, its characterized in that, the motor constitutes for: the rotation can be performed after the second member approaches the first member.

According to the utility model discloses, need not to adopt special screw or open the bottom outlet earlier, just can carry out the fastening operation of stereoplasm gypsum board.

Drawings

Fig. 1 is a central longitudinal section of the screwdriver (with the spindle in the advanced position).

Fig. 2 is a functional block diagram of the control circuit board.

Fig. 3(a) to 3(D) are explanatory views showing a fastening state of a gypsum board in a normal mode, in which fig. 3(a) and 3(B) show a case of a normal gypsum board, and fig. 3(C) and 3(D) show a case of a hard gypsum board.

Fig. 4(a) to 4(C) are explanatory views showing a fastening state of the hard gypsum board in the hard board fastening mode.

Fig. 5 is a flowchart of a hard plate fastening mode (normal).

Fig. 6 is a flowchart of the hard plate fastening mode (push drive).

Fig. 7(a) and 7(B) are graphs showing changes in the rotation speed of the brushless motor in each mode.

Description of the symbols

1 … screwdriver; 2 … main body case; 3 … gearbox; 4 … output; 5 … motor housing; 6 … holding the shell; 11 … brushless motor; 14 … rotating the shaft; a 26 … switch; a 32 … controller; 33 … control circuit board; 40 … drive a gear; 41 … a first spindle; 42 … clutch cam; 44 … second spindle; 51 … bar; 54 … sensor substrate; 60 … bit retention apertures; 70 … microcomputer; 71 … motor drive; 72 … current detection unit; 77 … mode switching button; 80A, 80B … gypsum board; 81 … screw; 82 … bumps; 83 … bottom hole; b … tool bit.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a central longitudinal sectional view of a rechargeable screwdriver 1 as an example of a screw fastening machine for gypsum boards. The screwdriver 1 has: a rear main body housing 2, and a front gear case 3. The gear case 3 is provided with an output portion 4.

The main body case 2 integrally includes: a motor housing 5 and a grip housing 6. The motor housing 5 extends in the front-rear direction. The grip housing 6 is in the shape of a ring connected to the rear of the motor housing 5. The main body case 2 is assembled by a pair of left and right half-divided cases 2a and 2a with a plurality of screws 7 and 7 … screwed from the right side.

The gear case 3 is divided into two parts, i.e., a rear-side housing 8 and a front-side housing 9. The rear side housing 8 is held at the front of the motor housing 5. The front housing 9 is exposed in front of the motor housing 5. The gear case 3 is assembled by screwing 4 screws 10 and 10 …, which penetrate the front and rear two cases 8 and 9 from the front of the front case 9, to the front end of the motor case 5.

A brushless motor 11 is housed in the motor case 5. The brushless motor 11 is an inner rotor type motor having: a cylindrical stator 12, and a rotor 13 disposed inside the stator 12. The brushless motor 11 is supported in the motor housing 5 in a direction in which a rotary shaft 14 provided to the rotor 13 extends in the front-rear direction. The stator 12 has a plurality of coils 15, 15 …. A sensor circuit board 16 is provided at the rear of the stator 12. The sensor circuit board 16 includes a rotation detection element not shown. The rotation detecting element detects the plurality of permanent magnets 17, 17 … provided on the rotor 13. The wires of the coils 15 are three-phase connected. The three-phase connected power supply line is led out from the lower part of the stator 12 into the grip housing 6. The signal line of the rotation detecting element is also led out from the lower portion of the stator 12 into the grip housing 6.

The rear end of the rotary shaft 14 is supported by a bearing 18 held on the rear inner surface of the motor housing 5. A centrifugal fan 19 is provided in front of the rotary shaft 14. An unillustrated exhaust port is formed outside the centrifugal fan 19 and on a side surface of the motor case 5. An air inlet, not shown, is formed in the side surface of the motor case 5 behind the air outlet. The front end of the rotary shaft 14 is supported by a bearing 20 held by the rear housing 8. The front end of the rotary shaft 14 protrudes into the gear housing 3. A pinion 21 is formed at the front end of the rotary shaft 14.

A grip portion 25 is formed along the vertical direction at the rear portion of the grip housing 6. A switch 26 for projecting the trigger 27 forward is provided at an upper portion in the grip portion 25. A forward/reverse switching lever 28 is provided above the switch 26. A forward/reverse lever switch 76 (fig. 2) that performs a switching operation in accordance with the operation of the forward/reverse switching lever 28 is provided between the switch 26 and the forward/reverse switching lever 28.

A battery mounting portion 29 is formed at a lower portion of the grip case 6. Battery pack 30 is slidably mounted on battery mounting portion 29 from the front. A terminal block 31 electrically connected to the battery pack 30 is provided in the battery mounting portion 29. A controller 32 is housed above the terminal block 31. The controller 32 includes a control circuit board 33. A switch board 34 is provided on the upper side of the controller 32. The switch plate 34 is exposed on the inner peripheral lower surface of the grip case 6. The switch board 34 is provided with a mode switching button 77 (fig. 2) and a mode indicator. A lamp 35 is provided on the front surface of the battery mounting portion 29. The lamp 35 irradiates the front of the second main shaft 44 of the output unit 4.

The output section 4 includes: a drive gear 40, a first main shaft 41, a clutch cam 42, a coil spring 43, and a second main shaft 44. The drive gear 40 meshes with the pinion 21 of the rotary shaft 14 in the rear housing 8. The first main shaft 41 is coaxially and integrally coupled to the drive gear 40. The rear end of the first main shaft 41 is supported by a bearing 45 held by the rear side housing 8. The clutch cam 42 is connected to the drive gear 40 via a ball 46 so as to be rotatable integrally therewith. A rear cam portion 47 is formed on the front surface of the clutch cam 42.

The front portion of the first main shaft 41 is inserted into a bottomed hole 48 provided at the rear portion of the second main shaft 44. The front end of the first main shaft 41 is coaxially supported in the bottomed hole 48 via a bearing 49.

A coil spring 43 is externally mounted to the first main shaft 41. The rear end of the disc spring 43 abuts against the front surface of the clutch cam 42. The leading end of the disc spring 43 abuts against the outer ring 50 of the bearing 49.

A rod 51 is provided on the axial center of the first spindle 41 so as to be movable forward and backward. The rear end of the rod 51 penetrates the rear side housing 8. The front end of the rod 51 protrudes into the bottomed hole 48 of the second main shaft 44. A rod 52 is provided in the rear of the rear housing 8 and in the motor housing 5. The lever 52 presses the rear end of the lever 51 forward by the torsion spring 53. A magnet 52a is provided at the upper end of the rod 52. A sensor substrate 54 including a sensor such as a hall element is provided behind the upper end of the rod 52. The upper end of the rod 52 biased rearward abuts the sensor substrate 54. The upper end of the rod 52 moves forward to separate the magnet 52a, whereby the sensor substrate 54 outputs an ON signal.

The second main shaft 44 is held by a bearing 55 in the front housing 9 so as to be movable forward and backward and rotatable. A flange 56 is formed at the rear end of the second main shaft 44. A front cam portion 57 is formed on the rear surface of the flange 56. The front cam part 57 faces the rear cam part 47 of the clutch cam 42. The front cam part 57 and the rear cam part 47 are engaged in the forward and reverse rotational directions in a state of abutting against each other.

The second main shaft 44 is biased to the advanced position of fig. 1 by a coil spring 43. A stopper 58 is supported on the front side housing 9. The flange 56 of the second spindle 44 abuts a stop 58 in the advanced position. The lever 51 is located at an advanced position pressed by the lever 52. The forward position lever 51 has a front end close to the inner bottom surface of the bottomed hole 48 of the second main shaft 44 in the forward position.

A bit holding hole 60 is formed at the front end of the second spindle 44. The bit B as a tip tool can be inserted into the bit holding hole 60 from the front. The bit retaining hole 60 has a regular hexagonal cross-section. A leaf spring 61 and balls 62, 62 pressed inward by the leaf spring 61 are provided on the second spindle 44 outside the bit holding hole 60. The bit B inserted into the bit holding hole 60 is elastically prevented from falling off by the balls 62, 62.

A lock ring 63 is screwed to the front outer periphery of the front side housing 9. An adjustment sleeve 64 tapered toward the front is detachably attached to the front end of the lock ring 63. A rubber cap 65 is fitted to the front end of the adjustment sleeve 64.

The bit B fitted to the bit holding hole 60 is inserted through the adjustment sleeve 64 and the rubber cap 65, and the tip thereof protrudes. When adjusting the fastening depth of the screw, the lock ring 63 is rotated and screw-fed in the front-rear direction, and the adjustment sleeve 64 is moved forward and backward. Then, the amount of protrusion of the bit B with respect to the rubber cap 65 changes. This enables selection of an arbitrary fastening depth.

Fig. 2 is a circuit block diagram of the control circuit board 33. The control circuit board 33 includes: a microcomputer 70, a motor driving part 71, and a current detecting part 72. The motor drive unit 71 drives the brushless motor 11 via the switching elements. The current detection unit 72 detects a current flowing through the brushless motor 11. The microcomputer 70 includes: CPU73, ROM74, and RAM 75.

The operation signals of the switch 26, the forward/reverse lever switch 76, the sensor board 54, and the mode switching button 77 are inputted to the microcomputer 70. The microcomputer 70 sets the rotation direction of the brushless motor 11 based on the signal from the forward/reverse lever switch 76. Then, the microcomputer 70 drives the brushless motor 11 via the motor driving unit 71. The microcomputer 70 sets the fastening mode based on the operation signal of the mode switching button 77. Then, the microcomputer 70 controls the rotation direction and the rotation speed of the brushless motor 11 in accordance with the program recorded in the ROM 74.

In the screwdriver 1 configured as described above, for example, as shown in fig. 3(a), a fastening operation can be performed on a general gypsum board 80A. This is the normal mode.

The bit B is inserted into the bit holding hole 60 fitted to the second main shaft 44, and the forward/reverse switching lever 28 is positioned at the forward rotation position. Next, the operator grips the grip portion 25, and causes the tip of the bit B to be locked to the head of the screw 81 that abuts against the surface of the gypsum board 80A (fig. 3 a). Next, the operator pushes the trigger 27. Then, the switch 26 is turned on, and power is supplied from the battery pack 30 to the brushless motor 11 via the control circuit board 33. Thereby, the rotor 13 rotates normally, and the rotation of the rotary shaft 14 is transmitted from the pinion 21 to the drive gear 40. When the drive gear 40 rotates at a reduced speed, the first main shaft 41 and the clutch cam 42 also rotate forward integrally with the drive gear 40. However, the second main shaft 44 is located at the forward position such that the front side cam part 57 is not engaged with the rear side cam part 47 of the clutch cam 42. Thus, the second main shaft 44 is not rotated, and the screw fastening is not performed.

Next, the operator pushes the grip 25 to advance the screwdriver 1. Then, the second main shaft 44 is retracted together with the bit B against the urging force of the coil spring 43. Thereby, the front cam part 57 of the second main shaft 44 engages with the rear cam part 47, and the rotation of the clutch cam 42 is transmitted to the second main shaft 44. Then, the bit B rotates in the normal direction together with the second main shaft 44, and the screw 81 is screwed into the gypsum board 80A.

As the screw fastening progresses, the driver 1 advances, and the tip of the rubber cap 65 abuts against the gypsum board 80A. Then, thereafter, as screwing in, only the second spindle 44 advances. When the front cam part 57 and the rear cam part 47 are separated from each other, the transmission of rotation to the second main shaft 44 is cut off, and the screw fastening is completed (fig. 3B). When the operator releases the pressing operation of the trigger 27, the switch 26 is turned off, and the rotation of the rotor 13 of the brushless motor 11 is stopped. When the bit B is separated from the screw 81, the second spindle 44 is returned to the advanced position by the urging force of the coil spring 43.

On the other hand, the push drive mode can be selected by operating the mode switching button 77 of the switch board 34. In the push drive mode, the brushless motor 11 is not immediately driven even if the operator pushes the trigger 27. In the push driving mode, when the microcomputer 70 detects that the second spindle 44 retreats together with the bit B, the brushless motor 11 is started to rotate forward, so as to save power. The backward movement of the second spindle 44 is monitored by the ON operation of the sensor substrate 54. When the bit B is pressed against the screw 81 and the second main shaft 44 is retracted, the rod 51 abutting against the inner bottom surface of the bottomed hole 48 is retracted. As a result, the lever 52 rotates rightward in fig. 1, and the upper end swings forward, turning ON the sensor board 54. At this time, the brushless motor 11 is driven. Thereafter, the front cam part 57 and the rear cam part 47 are engaged, and the rotation of the clutch cam 42 is transmitted to the second main shaft 44. In this way, the bit B rotates in the normal direction together with the second main shaft 44, and the screw can be fastened.

When the switch 26 is turned ON by pressing the trigger 27, the microcomputer 70 supplies power to the lamp 35 to turn ON the lamp 35. This allows the front side of the cutter head B to be irradiated from below, and therefore, the work can be easily performed even in a dark place. When the switch 26 is turned off by releasing the push-in of the trigger 27, the lamp 35 is turned off.

If the centrifugal fan 19 rotates together with the rotation of the rotary shaft 14, the outside air is sucked from the air inlet on the side surface of the motor housing 5. The external air passes between the stator 12 and the rotor 13 and is discharged to the outside through an exhaust port. Thereby, the brushless motor 11 is cooled.

As shown in fig. 3(C), a fastening operation of the gypsum board 80B, which is harder than the gypsum board 80A, may be performed. In this case, if fastening is performed in the normal mode, the gypsum pushed away by the screw 81 when screwed in may bulge on the surface of the gypsum board 80B as shown in fig. 3(D) to form a bulge 82. Therefore, the processed surface is deteriorated.

Therefore, in the screwdriver 1, the hard plate fastening mode (normal) and the hard plate fastening mode (push drive) can be selected by operating the mode switching button 77 of the switch plate 34. First, a hard plate fastening mode (normal mode) will be described based on the flowcharts of fig. 4(a) to 4(C) and 5.

As in the normal mode, the trigger 27 is pushed in a state where the grip portion 25 is gripped and the tip of the bit B is locked to the head of the screw 81 (fig. 4 a). The microcomputer 70 checks the ON signal of the switch 26 (YES in S1), and in S2, reverses the rotation speed of the brushless motor 11 to a predetermined rotation speed. From this point, the operator pushes the grip portion 25 to advance the screwdriver 1. Then, the second main shaft 44 moves backward together with the cutter head B, and the front cam part 57 engages with the rear cam part 47, so that the second main shaft 44 rotates reversely (rotates leftward). If the bit B is rotated leftward as described above, the screw 81 is pressed into the gypsum board 80B while being rotated leftward, and therefore, as shown in fig. 4(B), the screw 81 is pressed into the gypsum board 80B while discharging gypsum chips to the front surface side. Thereby, the bottom hole 83 is formed in the gypsum board 80B.

At S3, it is determined whether or not a predetermined time has elapsed since the motor at S2 was reversely rotated, based on a timer built in the microcomputer 70. Here, if it is confirmed that the predetermined time has elapsed, the microcomputer 70 causes the brushless motor 11 to rotate forward in S4, and causes the second main shaft 44 to rotate forward (rotate rightward). As a result, as shown in fig. 4(C), the screw 81 is screwed into the gypsum board 80B by rotating rightward in the bottom hole 83.

As the screw fastening progresses, the driver 1 advances, and the tip of the rubber cap 65 abuts against the gypsum board 80B. Then, thereafter, as screwing in, only the second spindle 44 advances. When the front side cam part 57 is separated from the rear side cam part 47, the transmission of rotation to the second main shaft 44 is interrupted. Accordingly, the operator releases the pressing operation of the trigger 27, and the microcomputer 70 confirms the OFF signal of the switch 26 (YES in S5), and stops the driving of the brushless motor 11 in S6.

On the other hand, the hard plate fastening mode (push driving) is the flowchart of fig. 6.

As in the normal push drive mode, the trigger 27 is pushed in a state where the tip end of the bit B is locked to the head of the screw 81 as in fig. 4 (a). The microcomputer 70 checks the ON signal of the switch 26 (YES in S11), and checks the ON signal of the sensor substrate 54 in S12. That is, if the operator pushes the grip portion 25 to advance the screwdriver 1, the second spindle 44 is retracted to retract the rod 51, and the sensor substrate 54 is turned ON. When the ON signal of the sensor board 54 is confirmed in S12, the microcomputer 70 reverses the brushless motor 11 in S13. As a result, the cutter head B rotates in the reverse direction (leftward rotation) together with the second main shaft 44, and as shown in fig. 4B, the screw 81 is pressed into the gypsum board 80B while rotating in the leftward direction, thereby forming the bottom hole 83.

At S14, it is determined whether or not a predetermined time has elapsed since the motor at S13 was reversely rotated, based on a timer built in the microcomputer 70. Here, if it is confirmed that the predetermined time has elapsed, the microcomputer 70 causes the brushless motor 11 to rotate forward in S15, and causes the second main shaft 44 to rotate forward (rotate rightward). As a result, as shown in fig. 4(C), the screw 81 is screwed into the gypsum board 80B by rotating rightward in the bottom hole 83.

As the screw fastening progresses, the driver 1 advances, and the tip of the rubber cap 65 abuts against the gypsum board 80B. Then, thereafter, as screwing in, only the second spindle 44 advances. When the front side cam part 57 is separated from the rear side cam part 47, the transmission of rotation to the second main shaft 44 is interrupted. Accordingly, the operator releases the pressing operation of the trigger 27, and the microcomputer 70 confirms the OFF signal of the switch 26 (YES in S16), and stops the driving of the brushless motor 11 in S17.

In the hard plate fastening mode (normal and push-drive), the screw 81 is rotated in the reverse direction once and then screwed into the gypsum board 80B. Thus, the gypsum chips are screwed in a state where the bottom hole 83 is formed by being discharged, and thereby, an instantaneous high load when the head of the screw 81 pushes the gypsum board 80B open can be reduced. Therefore, the raised portions 82 as in fig. 3(D) are not generated on the surface of the gypsum board 80B. This improves the processing of the fastening surface.

The screwdriver 1 of the above-described aspect includes: a brushless motor 11 (motor); and a first spindle 41 (first member) rotated by the brushless motor 11. In addition, the screwdriver 1 includes: a second spindle 44 (second member) movable in a direction approaching or separating from the first spindle 41 in the direction of the rotation axis of the first spindle 41; and a bit holding hole 60 (bit holding portion) that rotates integrally with the second main shaft 44. In the screwdriver 1, the second spindle 44 approaches the first spindle 41, so that the rotation of the first spindle 41 can be transmitted to the second spindle 44, and the second spindle 44 rotates in the normal direction to fasten a screw. Further, the driver 1 can be used in a hard plate fastening mode (fastening mode) in which the second main shaft 44 is once reversely rotated and then normally rotated when fastening the screw 81 to the gypsum board 80B.

With this configuration, the hard gypsum board 80B can be fastened without using a dedicated screw or a pilot hole.

The second main shaft 44 is reversed until a predetermined time elapses.

This enables the second main shaft 44 to be appropriately reversed.

The driver 1 according to the above-described embodiment can be used by selecting a normal mode (first fastening mode) when fastening the screw 81 to the gypsum board 80A (first gypsum board) and a hard board fastening mode (second fastening mode) when fastening the screw 81 to the gypsum board 80B (second gypsum board) having a different material from the gypsum board 80A.

With this configuration, the fastening mode can be used in different ways according to the material of the gypsum board. Thus, even with the hard gypsum board 80B, the fastening operation can be performed without using a dedicated screw or a pilot hole.

Hereinafter, a modified example will be described.

In the above-described aspect, the screw is screwed at a constant rotation speed after the reverse rotation is changed to the normal rotation. Fig. 7(a) shows a change in the rotation speed of the brushless motor 11 in each mode. In the normal mode, as shown by the broken line, the rotational speed increases from the start to the normal rotation side, and then the vehicle advances at a constant rotational speed. In contrast, even in the drive mode, the brushless motor 11 is started at different timing and the rotation speed changes in the same manner.

In the hard plate fastening mode, as shown by the solid line, the rotation speed is increased to the reverse rotation side from the start, then changed to the normal rotation side at the elapse of a predetermined time or at the timing when the threshold value of the current is reached, and then increased to the normal rotation side, and then advanced at a constant rotation speed.

On the other hand, as shown by the solid line in fig. 7B, in the hard plate fastening mode, the rotation speed may be reduced at a predetermined timing t (determined by the elapsed time or the current value of the motor) before the screw fastening is completed, and the brushless motor 11 may be rotated at a speed lower than normal until the fastening is completed. If the rotation speed of the second main shaft 44 is reduced before the fastening of the screw is completed in this way, the machined surface becomes good. The low speed at which the fastening is ended may be performed in a normal mode as shown by a broken line. The same can be done in the push drive mode.

In the above-described aspect, the rotation of the second main shaft is changed from the reverse rotation to the normal rotation in the hard plate fastening mode, but a fastening mode in which the rotation direction is always the normal rotation without being changed may be employed. For example, the control may be performed such that the vehicle is rotated forward at a low speed from the fastening start and rotated forward at a high speed from the middle. The switching between the low speed and the high speed may be performed in multiple stages. It is possible to lower from the high speed to the low speed again before the screw fastening is finished as in fig. 7 (B).

In the above-described embodiment, the timing of switching from the reverse rotation to the normal rotation is determined based on the elapse of a predetermined time, but other control may be performed. For example, the switch to the normal rotation may be made when the current value of the motor detected by the current detection unit is equal to or greater than a predetermined value, when the current value is smaller than the predetermined value, or when the accumulated power supply amount is equal to or greater than the predetermined value. In addition to these conditions, a predetermined time may be elapsed as a condition for switching.

As the motor, other motors such as a commutator motor can be used.

The grip housing may be formed in a linear shape protruding downward from the rear end of the motor housing, instead of a ring shape.

The screw fastening machine may be an AC machine that does not employ a battery pack.

Claims (11)

1. A screw fastening machine for a gypsum board, comprising:

a motor;

a first member rotated by the motor;

a second member movable in a direction approaching or separating from the first member in a direction of a rotation axis of the first member; and

a bit holding portion that rotates integrally with the second member,

the screw fastening machine for gypsum boards is configured such that: the second member being capable of transmitting the rotation of the first member to the second member by the approach of the second member to the first member, so that the second member is rotated forward to enable the fastening of the screw,

the screw fastening machine for gypsum boards is characterized in that,

the screw fastening machine for gypsum boards is configured such that: when fastening the gypsum board with a screw, the gypsum board can be used in a fastening mode in which the second member is once rotated in the reverse direction and then rotated in the normal direction.

2. Screw fastening machine for plasterboards according to claim 1,

the screw fastening machine for gypsum boards is configured such that: the reverse rotation of the second member is performed until a predetermined time elapses or a current value of the motor reaches a predetermined value.

3. Screw fastening machine for plasterboards according to claim 1 or 2,

the screw fastening machine for gypsum boards is configured such that: in the fastening mode, the rotation speed of the second member is reduced before the fastening of the screw is completed.

4. Screw fastening machine for plasterboards according to claim 1,

the motor is configured to: the rotation can be performed after the second part approaches the first part.

5. A screw fastening machine for a gypsum board, comprising:

a motor;

a first member rotated by the motor;

a second member movable in a direction approaching or separating from the first member in a direction of a rotation axis of the first member; and

a bit holding portion that rotates integrally with the second member,

the screw fastening machine for gypsum boards is configured such that: the second member being capable of transmitting the rotation of the first member to the second member by the approach of the second member to the first member, so that the second member is rotated forward to enable the fastening of the screw,

the screw fastening machine for gypsum boards is characterized in that,

the screw fastening machine for gypsum boards is configured such that: the first and second fastening modes can be selected for use when a first gypsum board is fastened by screws and when a second gypsum board different in material from the first gypsum board is fastened by screws.

6. A screw fastening machine for gypsum boards according to claim 5,

the second gypsum board is a harder material than the first gypsum board.

7. Screw fastening machine for plasterboards according to claim 5 or 6,

the screw fastening machine for gypsum boards is configured such that: the first fastening mode is a mode in which the second member always rotates forward, and the second fastening mode is a mode in which the second member rotates forward after temporarily rotating backward.

8. Screw fastening machine for plasterboards according to claim 7,

the screw fastening machine for gypsum boards is configured such that: in the second fastening mode, the rotation speed of the second member is reduced before the fastening of the screw is completed.

9. Screw fastening machine for plasterboards according to claim 6,

the screw fastening machine for gypsum boards is configured such that: the first fastening mode is a mode in which the second member normally rotates at a constant rotation speed until the fastening of the screw is completed, and the second fastening mode is a mode in which the second member normally rotates while changing the rotation speed at a predetermined timing.

10. Screw fastening machine for plasterboards according to claim 9,

the screw fastening machine for gypsum boards is configured such that: the rotation speed of the second member in the second fastening mode changes from low-speed rotation to high-speed rotation.

11. A screw fastening machine for gypsum boards according to claim 5,

the motor is configured to: the rotation can be performed after the second part approaches the first part.

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