JPS61293736A - Automatic screw tightening machine - Google Patents

Abstract

PURPOSE:To enable easy coupling between a driver bitt and a screw by forming an internal space in a driven clutch part for fixing a coupling pin as projected into said space and providing, on the other hand, a pin on a clutch shaft. CONSTITUTION:A driven clutch part 32 is so provided on the lower part of a driving clutch as to be freely rotatable. A clutch shaft 29 is inserted in the driven clutch part 32 and that a spring 33 is fitted between the shaft 29 and the driving clutch part 30. Also, the driven clutch part 32 has a hollow part and a coupling pin 34 is so provided as to be projected thereto. This coupling pin 34 has a semi-spherical part on the end thereof and gears with a pin 35 on the clutch shaft 29, thereby always transmitting the rotation of the clutch shaft 29 to the driven clutch part 32. Furthermore, a connecting mechanism is connected to the driven clutch part 32 and the rotation of a motor is transmitted to a driver bitt.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic screw tightening machine that transmits the rotation of a motor to a driver bit via a dog clutch disposed so as to be meshable, and tightens a predetermined screw. The present invention relates to an automatic screw tightening machine configured to apply motor rotation to a driver bit even when a clutch is disengaged.

Prior Art Conventionally, when fastening a workpiece placed at a predetermined position with a screw, a driver bit 14 that rotates under the rotation of a motor 19 is integrated with a chuck unit 15 that holds the screw, as shown in FIG. or driver bit 14
Automatic screw tighteners configured to move independently are common. In this type of automatic screw tightening machine 1, the motor 19
The rotation of the driver bit 1 is carried out via the dog clutch 41, which is disengaged when the driver bit 14 is in the uppermost position.
4, when the driver bit 14 is in the uppermost position, the driver bit 14
is configured so that it does not rotate. In this automatic screw tightening machine, after the chuck unit 15 has been lowered to a predetermined position, when the driver bit 14 is roughly lowered by itself, the tip of the driver bit 14 will tighten the screw into the chuck unit 15.
The tip of the screw touches the workpiece. In this state, when the driver bit 14 is further lowered, the dog clutch 41 is engaged and the driver bit 14 is connected to the motor 1.
It receives rotation of 9 and rotates.

Problems to be Solved by the Invention In the automatic screw tightening machine described above, when the screw held by the chuck unit 15 is in an upright position when it comes into contact with the workpiece, the driver bit 14 is easily fitted. If the position is even slightly tilted, remove the driver bit 14.
The tip of the screw may come into contact with the upper end of the screw head and the screw may not fit, and if the screw separates from the chuck unit 15 before the dog clutch 41 engages, there are disadvantages such as the screw falling over on the workpiece. It is occurring.

Means for Solving the Problems The present invention is aimed at eliminating the above-mentioned drawbacks.A rotary drive source is fixed to the housing 18 of the driver body 12, and a clutch is attached to the drive shaft so as to rotate in response to the rotation. The shafts are connected. A driving clutch portion is attached to this clutch shaft so as to rotate together with the clutch shaft, and a driven clutch portion is disposed on this clutch shaft so as to be able to engage with the driving clutch portion. Further, a driver bit is connected to the driven clutch portion so as to rotate together with the driver bit.

The driven clutch portion is provided with a hollow portion, and the driven clutch portion is provided with a hollow portion.
A locking pin is fixed so as to protrude into this hollow part. Further, a pin is implanted in the clutch shaft, and the pin is positioned in the hollow portion so that the pin and the locking pin are slightly locked.

Function: In the automatic screw tightening machine described above, when the motor rotates, the rotation is transmitted to the clutch shaft, and the pin implanted therein rotates together. At this time, the driving clutch section and the driven clutch section are not engaged, but the locking pin in the hollow part of the driven clutch section slightly contacts the pin, and as the pin rotates, the driven clutch section is rotated. Therefore, even before the dog clutch engages, driver bits 1 to 1 rotate, so when the driver bit descends and reaches the position where its tip contacts the upper end of the screw head held in the chuck unit in an inclined position. , the driver bit can be easily fitted. Also, before the driving clutch section and the driven clutch section engage, the driver bit once fits into the screw and screws the screw into the workpiece, but if even a slight load torque is generated on the driver bit, the driven clutch section The locking pin is pushed up as the clutch shaft and pin of the drive clutch unit rotate, the locking pin is disengaged from the pin, and the driver bit stops rotating.

Example.

Examples will be described below with reference to the drawings. In FIGS. 1 to 5, reference numeral 1 denotes an automatic screw tightening machine, which has a support 3 implanted in a base 2. As shown in FIG. A fixing plate 4 is fixed to the support column 3, and an upper bracket 5 and a lower bracket 6 are fixed to the fixing plate 4 above and below. A cylinder 7 is fixed to the upper bracket 5, and a driver mounting base 8 is fixed to its rod (not shown). A chuck stand 10 elastically biased by a first spring 9 is arranged on the driver mount 8 at a predetermined interval. They are configured to move together along the same line to a predetermined position. Further, a driver main body 12 is provided on the upper part of the driver mounting base 8.
is held, and this driver body 12 is connected to the connecting mechanism 1.
The screwdriver bit 14 is configured to rotate through the screwdriver bit 3.

On the other hand, a chuck unit 15 is fixed to the chuck base 10, and the driver bit 14 is inserted into the chuck unit 15 and screws a screw (not shown) held by the chuck claw 15a into a predetermined position. is configured to do so.

The driver main body 12 has an inner cylindrical portion 17 and a housing 18 that is screwed into the bottom portion of the inner cylindrical portion 17.
is fixed to the driver mounting base 8 with bolts via a fixture 16 which will be described later. However, this driver main body 12 has a motor 19 as a rotational drive source fixed to the housing 18, and an input disk 21 of a differential planetary mechanism 20 constituting an automatic transmission is connected to the drive shaft 19a of the motor 19. has been done. This input disk 21 has an annular portion 21a on its outer periphery, and this annular portion 21a transmits power formed by circumferential grooves 23a of a plurality of planetary cones 23 held with their axes inclined by a cone holder 22. It is configured to frictionally engage the surface. Moreover, this planetary cone 23 has a flat surface 23 on the back side.
A cam disk 24 is frictionally engaged with this flat surface 23b, and this planetary cone 23 is connected to the input disk 2.
It is held between 1 and 1. Further, a speed change ring 25 is located around the planetary cone 23 so as to be in contact with its conical surface, and this ring 25 is held by a plurality of piano wires 26, which will be described later. This piano wire 26 is bent in response to the torque applied to the speed change ring 25, the position of frictional engagement of the speed change ring 25 with the conical surface 23c changes, and the reduction ratio determined by the frictional engagement position of the speed change ring 25 changes continuously. As a result, the number of rotations of the cam disc 24 is reduced. In addition, the speed change ring 2
The engagement position a of No. 5 is the position shown in Fig. 4 (a: b=c
: The cam disk is configured so that it rotates to zero when it reaches the position that satisfies d.

A pressure regulator m27 is connected to the cam disc 24, and the cam disc 24 is configured to press the planetary cone 23. The pressure regulating mechanism 27 has a connecting shaft 28, which passes through the cam disk 24 and is rotatably held via a bearing fixed to the upper part of the inner cylindrical portion 17. . An oil seal mechanism is arranged around the connecting shaft 28, and an oil seal mechanism is arranged around the connecting shaft 28.
8 is sealed so that the differential planetary mechanism and the pressure regulating mechanism 27 are shielded by the inner cylindrical portion 17. Further, oil is filled between the housing 18 and the inner cylinder portion 17 to prevent wear of the differential planetary mechanism 20.

Further, the connecting shaft 28 has a hexagonal engagement hole 28a at its lower end.
The hexagonal protrusion 29a of the clutch shaft 29, which is part of the clutch mechanism disposed in the inner cylindrical portion 17, is removably fitted into the hexagonal engagement hole 28a, thereby connecting the connecting shaft 28 and the clutch shaft. 29 are configured to rotate together. A drive clutch section 30 is rotatably fitted into the lower end of the clutch shaft 29. This drive clutch section 30 and the clutch shaft 29 are connected by a second spring 31, and the connection mechanism 13 and driver bit 14 are connected to each other by a second spring 31. The second spring 31 is configured to absorb inertia during rotation. A driven clutch section 32 is rotatably disposed below the driving clutch section 30, and the clutch shaft 29 is inserted into the driven clutch section 32. 3 springs 33 are arranged.

Further, the driven clutch portion 32 has a hollow portion, and a locking pin 34 is attached so as to protrude into the hollow portion. This locking pin 34 has a hemispherical portion at its tip, and this locking pin 34 engages with a pin 35 implanted in the clutch shaft 29, so that the rotation of the clutch shaft 29 is constantly controlled by the driven clutch portion 32.
It is structured and configured to be transmitted to. Further, the connecting mechanism 13 is connected to the driven clutch section 32, and the rotation of the motor 19 is configured to be transmitted to the driver bit 14.

On the other hand, a torque adjustment sleeve 3 is provided on the outer periphery of the inner cylindrical portion 17.
6 is slidably disposed, and a plurality of piano wires 26, which are linear elastic bodies, are fixed between the bottom of the inner cylindrical portion 17 and the ring 25.

The torque adjustment sleeve 36 has notched grooves 368 at equal intervals on its outer periphery, and the piano wire 26 is configured to pass through the notched grooves 36a. Further, the torque adjustment sleeve 36 has a collar part, and an adjustment bolt 37 rotatably held at the bottom of the inner cylinder part 17 at that position is screwed into this collar part, so that the torque By changing the height position of the adjustment sleeve 36, the spring constant of the piano wire 26 changes, and the tightening is configured so that an elastic force corresponding to the torque is obtained.

In the automatic screw tightening machine described above, when the motor 19 rotates, the speed is reduced by a reduction ratio determined by the position where the speed change ring 25 frictionally engages with the conical surface 23c of the planetary cone 23, and the rotation is caused by the rotation of the planetary cone 23 from the input disk 21. The signal is transmitted to the cam disk 24 via the cam disk 24. As the cam disc 24 rotates, the clutch shaft 29 also rotates.

At this time, the driving clutch section 30 and the driven clutch section 32 are not engaged, but as the clutch shaft 29 rotates, the pin 35 also rotates, so that the pin 35 protrudes into the hollow part of the driven clutch section 32. It engages with the stop pin 34, and the rotation of the clutch shaft 29 is transmitted to the driver bit 14 via the connecting mechanism 13.

In this state, when the driver body 12 descends and the chuck unit 15 stops at a predetermined position, the driver bit 14
presses the screw in the chuck jaw 15a against the workpiece. At this time, since the driver bit 14 is rotating, the driver bit 14 easily fits into the screw regardless of the orientation of the screw. The driver bit 14 fits into the screw and screws the screw into the workpiece, but if the screw bites into the workpiece and even a slight load torque is generated, the rotation of the clutch shaft and pin 35 causes the locking pin 34 and the driven The clutch portion 32 is pushed upward, and the rotation of the clutch shaft is no longer transmitted to the driver bit 14.

Furthermore, when the driver main body 12 descends, the driven clutch portion integrated with the driver bit 14 rises relatively, the driving clutch portion 30 and the driven clutch portion 32 are engaged, and the driver bit 14 holds this screw in a predetermined position. Screw into position. Along with this, the torque for tightening the screw increases, and when the load torque of the driver bit 14 increases and its rotational speed decreases, the speed change ring 25 receives torque in accordance with the load torque, and as shown in FIG. Piano wire 26 as shown
bends. Therefore, the speed change ring 25 slides along the conical surface 23C of the planetary cone 23, and its frictional engagement position changes to a frictional engagement position where the torque applied to the speed change ring 25 and the elastic force of the piano wire 26 are balanced. The speed change ring 25 stops.

Furthermore, as the tightening torque increases, the ring 25
The movement of the cam disc 24 continues, and the reduction ratio becomes larger and larger until finally, even though the input disc 21 rotates, the cam disc 24 reaches zero rotation, and the driver bit 14
stops with the predetermined torque maintained, and the screw tightening is completed.

As described in detail, the present invention is configured to transmit the rotation of a motor to a driver bit via a dog clutch, and a hollow portion is provided in the driven clutch portion of the dog clutch, and a locking member is engaged in the hollow portion. While protruding the pin,
The clutch shaft is positioned up to this hollow part, and a pin is implanted in this clutch shaft so that it slightly engages with the locking pin, so that the driving clutch part and the driven clutch part are not engaged. Even when not in use, the rotation of the motor can be transmitted to the driver bit by the engagement between the pin and the locking pin, and the engagement between the driver bit and screw can be maintained regardless of the orientation of the screw held in the chuck unit. This method has advantages such as being easy to perform and ensuring reliable screw tightening work.

[Brief explanation of drawings]

Figure 1 is an enlarged sectional view of the main part of the present invention, and Figure 2 is A of Figure 1.
FIG. 3 is an overall explanatory diagram of the present invention; FIG. 4 is an enlarged sectional view of essential parts showing the operating state of the differential planetary mechanism according to the present invention; FIG. FIG. 6 is a perspective view of a main part of a torque adjusting sleeve according to the present invention, FIG. 6 is a sectional view of a main part showing an operating state of a differential planetary mechanism according to the present invention, and FIG. 7 is an overall explanatory diagram of a conventional example. 1 Automatic screw tightening machine, 2 Base, 3 Support, 4 Fixed play 1~. 5 upper bracket, 6 lower bracket, 7 cylinder, 8 driver mounting base, 9 first spring, 10 chuck base, 11 guide shaft, 12 driver body, 13 connecting mechanism, 14 driver bit, 15 chuck unit, 15a chuck claw, 16 Fixing tool, 17 Inner cylinder part,
18 housing, 19 motor, 19
a drive shaft, 20 differential planetary mechanism, 21 human power disk, 21a annular portion, 22 cone holder,
23 planetary cone, 238 circumferential groove, 24 cam disc, 25 ring, 26 piano wire,
27 pressure regulating mechanism, 28 connecting shaft,
28a Hexagonal engagement hole, 29 Clutch shaft, 29
a hexagonal protrusion, 30 drive clutch portion, 31 second
Spring, 32 Driven clutch portion, 33 Third spring,
34 Locking pin, 35 Pin, 36 Torque adjustment sleeve, 36a notch groove, 37 Adjustment bolt, 41 Dog clutch,

Claims (1)

[Claims] A rotary drive source is fixed to the housing 18 of the driver main body 12, a clutch shaft 29 is connected to the drive shaft so as to rotate in response to the rotation, and the clutch shaft 29 is rotated integrally with the clutch shaft 29. Attaching the drive clutch section 30 to the
In an automatic screw tightening machine, a driven clutch part 32 is disposed along the clutch shaft 29 so as to be able to engage with a drive clutch part 30, and a driver bit 14 is rotated integrally with the driven clutch part 32. A hollow part is provided in the clutch part 32, and the locking pin 34 is fixed so as to protrude into this hollow part, while the clutch shaft 2
9. An automatic screw tightening machine characterized in that a pin 35 is installed in the hollow part 9, and the pin 35 is positioned in the hollow part so that the pin 35 and the locking pin 34 are engaged with each other.