JPH0871867A - Screw fastening machine - Google Patents

Abstract

PURPOSE: To provide a screw fastening machine preventing the happening of a fastening failure. CONSTITUTION: Plural driver units 7 are installed on an elevating driver base 6. A guide base integrally elevated with the driver base 6 is disposed below the driver base 6, and a driver bit 9 extended from the driver unit 7 is guided into a specified position by the guide base 11. The guide base 11 is provided with a vibrating part 12 formed of a vibrating cylinder 12b and a vibrating plate 12a connected to the vibrating cylinder 12b and constraining the driver bit 9 to guide it into the specified position and moreover movable on the horizontal plane. Since the vibrating plate 12a is thus vibrated on the horizontal plane by operating the vibrating cylinder 12b to vibrate the driver bit 9, the driver bit 9 and a workpiece side screw can be positively engaged with each other so as to suppress the happening of a screw fastening failure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw tightening machine for tightening a screw, and more particularly to a screw capable of reliably engaging a screw tightening tool such as a driver bit with a screw head. Regarding fasteners.

[0002]

[Prior art of branch surgery] Conventionally, when tightening screws on a work that has multiple rows of screw tightening positions vertically and horizontally, it is possible to simultaneously tighten multiple screws on the work with multiple driver units. Fasteners are generally well known. This multi-axis screw tightener mounts and fixes multiple screw tightening driver units on a table that can be moved up and down and moved back and forth, and these output shafts and screw tightening tools such as driver bits or box bits are connected by a universal joint. They are connected to each other, and each screw tightening tool is rotatably guided by a guide plate having a guide hole formed corresponding to the screw tightening position of the work, and is adapted to correspond to the screw hole position of the work.

[0003]

In the multi-axis screw tightening machine having the above-mentioned structure, since a plurality of screw tightening tools are constrained by the guide plate for positioning, the screw tightening tools move forward, backward, left and right from that position. It has become impossible to work on. From this, in the work of finally re-tightening the screw temporarily tightened on the work, the screwing amount of the temporary tightening is shallow and the screw tightening tool may engage with the screw when the screw is inclined. However, there are drawbacks such as inadequate tightening, and when holding the screw in the screw tightening tool and then screwing the screw into the work,
If the screw is slightly inclined for some reason, it becomes impossible to engage the screw with the screw hole of the workpiece, and there is a drawback that defective tightening may occur.

The present invention was created in view of the above problems, and an object of the present invention is to provide a screw tightening machine which prevents the occurrence of defective tightening.

[0005]

A plurality of driver units are installed on a driver stand, a guide stand is arranged below the driver stand, and a screw tightening tool extending from the driver unit is guided to a predetermined position by the guide stand. In the screw tightening machine described above, a vibrating section is provided on the guide base, and the vibrating section guides the screw tightening tool extending from the driver unit to a predetermined position, and the vibrating section vibrates the screw tightening tool. There is. In this screw tightening machine, the vibrating section is provided with a plurality of reciprocating drive sources installed on the guide table, and is connected to the reciprocating drive sources and restrains a screw tightening tool extending from the plurality of driver units to provide a predetermined vibration. It consists of a vibrating plate that guides to a position and can move on a horizontal plane. The vibrating plate in this vibrating part has an engaging hole, and it corresponds to the center position of the engaging hole on the guide base. Then, a pin having a diameter smaller than the diameter of the engaging hole is implanted. The engaging hole of the diaphragm is engaged with this pin, and the diaphragm can be moved by the difference between the diameter of the engaging hole and the diameter of the pin.

[0006]

In the screw tightener having the above structure, the driver unit is operated to rotate the screw tightening tool, and the driver base and the guide base are lowered to engage the screw tightening tool with the screw head arranged on the work. Move to position. At this time, when the screws are temporarily tightened, the axes of the screws are not uniformly vertical, so that all of the plurality of screw tightening tools do not always reliably engage the screw heads. Therefore, when the reciprocating drive source of the vibrating section operates from this state, the diaphragm vibrates differentially between the diameter of the engagement hole and the diameter of the pin, and the screw tightening tool also vibrates with the vibration of the diaphragm. Due to this vibration, the screw tightening tool that is not engaged with the screw head engages with the screw head, corrects the axis of the screw in the correct direction, and the rotation of the screw tightens the work securely. it can.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 and FIG. 2, reference numeral 1 denotes a screw tightening machine, which is provided with a work table 2 for holding a work in which four screw tightening positions are arranged on a straight line, and the work table 2 has a rear upper surface extending in a vertical direction. The support frame 3 is installed.
A bracket 4 is fixed to the front surface of the support frame 3, and an ascending / descending cylinder 5 having a rod 5a extending vertically downward is installed above the bracket 4.
A driver base 6 located on a horizontal plane is connected to the rod 5a of the lifting cylinder 5.
Four driver units 7 are arranged above. These driver units 7 are generally commercially available for automatic screw tightening, and a universal joint 8 is connected to each output shaft 7a that is rotated by driving a motor. The universal joint 8 is a so-called universal joint that can bend and rotate the joints 8a provided near both ends to transmit the rotation on the input side in all directions. A screw tightening tool is provided on each joint 8a below. Driver bit 9 is connected.

A guide shaft 10 extending vertically is fixed near both sides of the rear portion of the driver base 6, and the upper end of the guide shaft 10 is inserted through the upper portion of the bracket 4 and extends upward. A stopper 10b in which a bolt is hung down and screwed into an arm 10a extending in the horizontal direction is attached to the uppermost end. Further, the lower end of the guide shaft 10 is inserted through the lower portion of the bracket 4 and extends further downward, and a guide base 11 extending in the horizontal direction is installed at the lower end thereof. The guide base 11 is made of a plate-shaped member having substantially the same area as the driver base 6, and a vibrating portion 12 is installed on the upper surface thereof.

As shown in FIGS. 3 to 5, the vibrating portion 12 is disposed on the upper surface of the guide base 11a and the vibrating plate 12a on the rear upper surface and the side upper surface of the guide base, respectively. A vibration cylinder 12b, which is an example of a reciprocating drive source arranged such that their axes are orthogonal to each other.
Consists of Vibration cylinder 1 in the vibrating section 12
The rod 12c of 2b is inserted into a connecting portion 12d provided on the vibration plate 12a corresponding to the position of the vibration cylinder 12b, and is connected to the connecting portion 12d with a gap. The gap between the connecting portion 12d and the rod 12c of the vibration cylinder 12b corresponds to the difference between the diameter of the engagement hole 12e and the diameter of the pin 11a described later.

Further, an engaging hole 12e for positioning is formed at a diagonal of the vibrating plate 12a in the vibrating section 12,
A pin 11a is planted on the upper surface of the guide 11 corresponding to the engaging hole 12e. The diaphragm 12a is the pin 1
1a is engaged and installed, but comparing the outer diameter of the pin 11a and the diameter of the engaging hole 12e, the engaging hole 12e is formed to have a larger diameter, and the vibrating plate 12a is installed. Even in this case, the diaphragm 12a can move on a flat surface although it is small.

The vibrating plate 12a is provided with four guide holes 12f penetrating the vibrating plate 12a at equal intervals in a straight line. The guide holes 12f have a length sufficient to project vertically from the vibrating plate 12a. Each sleeve 13 is fitted and fixed, and the driver bit 9 is inserted into the sleeve 13 so as to be rotatable and movable up and down in the sleeve 13. With the inner surface of the sleeve 13 and the outer diameter of the driver bit 9 slightly contacting each other, when the driver bit 9 rotates during screw tightening, a slight friction is generated between the driver bit 9 and the sleeve 9. This sleeve 13
The driver bits 9 extending from the driver unit 7 under the guidance of are arranged in a straight line at equal intervals. In addition, the guide hole 12 of the vibration plate 12a of the guide base 11
A portion corresponding to the periphery of f is hollowed out so that the sleeve 13 does not come into contact with it even if the sleeve 13 vibrates to some extent.

In the screw tightening machine 1 having the above-described structure, first, when the work, in which the screws are temporarily tightened in the screw holes formed on the work table 2 at equal intervals on a straight line, is placed and held,
The lifting cylinder 5 operates to move the driver base 6 and the guide base 11 vertically downward, and the driver unit 7 operates to rotationally drive the driver bit. The movement of the guide base 11 also moves the diaphragm 12a in the vertical direction, and the elevation thereof is stopped when the stopper 10b above the guide shaft 10 is installed on the upper surface of the bracket 4. This descent stop position is the position where the tip of the driver bit 9 reaches the screw head.

At this time, since the screw is only temporarily tightened in the screw hole of the workpiece, the screwdriver bit 9 that has descended in a very unstable state is likely to be inclined. It is in a state. Therefore, even if the driver bit 9 reaches the head of the screw, it does not necessarily engage with the drive hole of the screw head, and if the driver bit 9 is rotated in this state to start tightening, it is inevitable. Inadequate tightening screws occur.

Therefore, in the present screw tightening machine 1, the lifting cylinder 5 is operated to lower the driver base 6, and at the same time, the vibration cylinder 12b is operated. The vibrating cylinder 12b reciprocates so that the rod 12c is slightly retracted forward, and the vibration plate 12a is actuated by the vibrating plate 12a to move the vibrating plate 12a in the horizontal and horizontal directions of the engaging hole 12e and the pin 11a. The difference with the diameter vibrates at the same time, and the sleeve 13 also vibrates together with the difference. At this time, the direction in which the diaphragm 12a moves due to the operation of one of the vibration cylinders 12b is in the other vibration cylinder 12b.
The radial load is applied to the rod 12c of the cylinder 12b, but the rod 12c of the vibration cylinder 12b and the diaphragm 1
Since there is a gap corresponding to the difference between the diameter of the engagement hole 12e and the diameter of the pin 11a between the connecting portion 12d of the 2a and the connecting portion 12d of the 2a, the vibration cylinders 12b are actuated by the vibration cylinders 12b. The radial load does not act on the rod 12c.

Here, the driver bit 9 is a sleeve 13
Since it is inserted in such a state that it slightly contacts with, the driver bit 9 therein also vibrates sufficiently due to the vibration of the sleeve 13, and the driver bit 9 vibrates and is unstable with the driver bit 9. Driver bit 9 is securely engaged with a screw that has been in a disengaged state or a screw that is disengaged from driver bit 9 and is not engaged, and the posture of the screw is correctly corrected, and the screw causes the screw to work on the workpiece. Tighten. At this time, for example, even if only one driver bit 9 is engaged with the screw before the other driver bits 9, the distance from the diaphragm 12a to the screw head is large, so that the other driver bits 9 are The vibration does not stop, and the other driver bits 9 also sequentially engage with the screw head.

[0016]

The screw tightening machine described in detail above rotates the driver bit by the operation of the driver unit and at the same time operates the vibrating cylinder to vibrate the vibrating plate of the vibrating portion to vibrate the difference in diameter between the engaging hole and the pin. Since the vibration is transmitted to the driver bit by this vibration, even if the driver bit and the screw on the work side are not engaged due to this vibration, it is possible to engage it and also to hold the screw in the driver bit. The screw can be matched with the screw hole even when feeding to the screw hole of the workpiece. Especially, in a multi-axis screw tightener that installs multiple driver units and tightens multiple screws at the same time, screw tightening failure It is possible to suppress the occurrence of.

[Brief description of drawings]

FIG. 1 is a side view of a screw tightener according to the present invention.

FIG. 2 is a front view of the screw tightener according to the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part taken along the line AA in FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

5 is a sectional view taken along line CC in FIG.

[Explanation of symbols]

 1 Screw Tightener 2 Worktable 3 Support Frame 4 Bracket 5 Lifting Cylinder 5a Rod 6 Driver Stand 7 Driver Unit 7a Output Shaft 8 Universal Joint 8a Joint 9 Driver Bit 10 Guide Shaft 10a Arm 10b Stopper 11 Guide 11a Pin 11b Notch Hole 12 Vibration part 12a Vibration plate 12b Vibration cylinder 12c Rod 12d Connection part 12e Engagement hole 12f Guide hole 13 Sleeve

Claims (2)

[Claims] 1. A plurality of driver units are installed on a vertically movable driver stand, and a guide stand that moves up and down integrally with the driver stand is arranged below the driver stand, and a screw tightening tool extending from the driver unit is provided on the guide stand. In a screw tightening machine guided to a predetermined position by means of a vibrating section, the vibrating section guides the screw tightening tool extending from the driver unit to a predetermined position, and the vibrating section vibrates the screw tightening tool. A screw tightening machine characterized in that 2. The vibrating section is provided with a plurality of reciprocating drive sources installed on a guide table, and is connected to the reciprocating drive sources and restrains a screw tightening tool extending from the plurality of driver units to a predetermined position. The vibrating plate in this vibrating portion is provided with an engaging hole, and on the guide base, one corresponding to the center position of the engaging hole is provided. A pin with a diameter smaller than the diameter of the engaging hole is implanted, the engaging hole of the diaphragm engages with this pin, and the diaphragm can be moved by the difference between the diameter of the engaging hole and the diameter of the pin. The screw tightening machine according to claim 1, wherein