JPH0761584B2 - Automatic screw tightener - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of an automatic screw tightening machine equipped with a novel reciprocating drive source that gives a reciprocating motion to a driver bit for tightening a screw.

[Prior Art] and [Problems to be Solved by the Invention] Generally, in the case of an automatic screw tightener for tightening a screw to a work, a driver bit that rotates by receiving rotation of a motor starts descending due to an operation of a cylinder, and tightening work is performed. When the above is completed, it is configured to return to the ascending state by the returning movement of the cylinder. In this type of screw tightener, the descending speed of the driver bit is determined by the moving speed of the rod of the cylinder,
Moreover, since the impact load when the rod reaches the bottom end becomes large, the moving speed of the driver bit cannot be increased above a predetermined speed, and the cycle time required for screw tightening cannot be shortened above a certain level. Has the drawbacks of.

As a device for eliminating this drawback, an automatic screw fastening machine described in Japanese Patent Application No. 1-167681 has been invented. This automatic screw tightening machine 1 has a column 2 fixed to a base (not shown) as shown in FIG. 4, and a driver base 6 and a chuck base 7 are movable along the column 2. You are being guided.
A driver bit 11 that is rotated by the rotation of a drive motor 9 is attached to the driver base 6, and a chuck body 13a into which the driver bit 11 is inserted and a rotatable body are mounted on the chuck base 7 on the chuck base 7. A chuck unit 13 is fixed, which is attached and is constituted by a pair of chuck claws 13b that are biased so as to close the movement path of the driver bit 11 by closing the tip by a spring (not shown). The column 2 has a roller shaft 18 extending parallel to the driver bit 11.
Are rotatably arranged, and are configured to be rotatable by receiving rotation of the rotary drive source 23 fixed to the upper end of the column 2. Rotating rollers 16 and 17 are fixed to the roller shaft 18 at predetermined intervals corresponding to the driver table 6 and the chuck table 7, respectively. As the roller shaft 18 rotates, the rotating rollers 16 and 17 are fixed. It is configured to rotate integrally. Circumferential cam grooves 16a and 17a composed of a descending curve portion having a predetermined descending stroke and an ascending curve portion having a predetermined ascending stroke are provided on the outer circumferences of the rotating rollers 16 and 17 on the driver table 6 side and the chuck table 7 side, respectively. The circular cam groove 16a on the driver base 6 side is removed, and the lowering stroke of the circumferential cam groove 16a on the chuck base 7 side is longer than the lowering stroke. Moreover, the circumferential cam groove
The cam followers 15 and 15a attached to the driver base 6 side and the chuck base 7 side are respectively fitted and positioned in 16a and 17a, and the driver base 6 and the chuck base 7 are arranged at a predetermined interval. The driver table 6 is moved independently after the chuck table 7 is stopped. In this automatic screw tightening machine 1, a conveying device (not shown)
If it is attempted to operate it in synchronism with the transport operation, the position detection sensor (not shown) that keeps the transport speed of the transport device constant and outputs a synchronization signal is attached to the transport device. If there is no other method than mounting and activating the automatic screw tightening machine 1 with a synchronization signal from this position detection sensor, and if the transport device slows down the speed at startup, the automatic screw tightening is synchronized with the transport device. In addition to the inability to operate the machine 1, even if there is a rotational drive source for the conveying device, the roller shaft 18 cannot be rotated by utilizing this, which causes new defects such as an increase in the cost of the device. ing.

SUMMARY OF THE INVENTION The present invention is intended to eliminate the above-mentioned drawbacks, and improves the reciprocating drive source for reciprocating a driver bit for tightening a screw on a work and at the same time, enables the power of the reciprocating drive source to be obtained from the outside. Is to provide a machine.

[Means for Solving the Problem] In order to achieve the above object, a driver base and a chuck base are movably guided along a column. A driver bit that rotates in response to the rotation of the drive motor is mounted on the driver base, and a chuck body through which the driver bit is inserted and a chuck base are rotatably mounted on the chuck base and the tip is closed by a spring to move the driver bit. A chuck unit including a pair of chuck claws biased so as to block the path is attached.

A roller shaft extending parallel to the driver bit is rotatably arranged in the column, and a rotating roller is arranged on the roller shaft so as to rotate integrally with the driver base and the chuck base, respectively. ing. Circumferential cam grooves each having a descending curve portion having a predetermined descending stroke and an ascending curve portion having a predetermined ascending stroke are formed on the outer periphery of each of the rotation rollers on the driver table side and the chuck table side. The lower stroke of the side circumferential cam groove is longer than the lower stroke of the chuck side circumferential cam groove. Further, cam followers attached to the driver base side and the chuck base side are respectively fitted and positioned in these circumferential cam grooves,
The driver base and the chuck base are arranged so as to be spaced apart from each other by a predetermined distance.

The roller shaft is arranged so as to project from below the column. On the other hand, below the roller shaft, a rotary shaft extending in a direction intersecting with the roller shaft is rotatably arranged. Also,
The roller shaft and the rotating shaft are connected to each other via a rotation transmitting mechanism, and the rotation applied to the rotating shaft is transmitted to the roller shaft.

In addition, a driven sprocket is attached to one end of the rotary shaft so as to rotate integrally, and a drive source can be connected to the driven sprocket from the outside.

[Operation] In the above automatic screw tightening machine, when the desired work is placed below the driver bit and the screw tightening start command signal is output, the rotary drive source rotates and the driver bit rotates, and at the same time, the outside of the conveyor device or the like. The driving force is transmitted from the drive source to the driven sprocket, the driven sprocket rotates in synchronization with the transport speed of the transport device, and the rotary shaft starts to rotate integrally with this. The rotation of the rotating shaft is transmitted to the roller shaft via the rotation transmitting mechanism, and the rotating roller rotates one rotation. During this time, the cam followers attached to the driver base side and the chuck base side are fitted in the circumferential cam grooves on the outer circumference of the rotating roller, so that the cam followers follow the descending curve portion of the circumferential cam groove of the rotating roller. It moves, and the driver table and the chuck table descend. At this time, since the descending stroke of the descending curve portion of the circumferential cam groove on the driver base side is longer than that of the circumferential cam groove on the chuck base side, the driver base descends even after the chuck base has descended a predetermined stroke and stopped. Then, the driver bit integrated with this can be inserted through the chuck unit to tighten the screw held by the chuck claw onto the work. After that, each cam follower moves along the rising curve portion of the circumferential cam groove, and the driver base and the chuck base return to the upper position to prepare for the next work.

Embodiments Embodiments will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is an automatic screw tightening machine, which has a column 2 fixed upright on a base 1a. Two slide guides 3 extending in parallel along the upright surface are fixed to the column 2. First sliders 4a, 4a are reciprocally mounted on the slide guides 3, respectively, and the slide guides are mounted on the first sliders 4a, 4a via a first mounting member 5a fixed over them. A driver base 6 extending in a direction intersecting with 3 is attached.
Also, second sliders 4b, 4b are reciprocally mounted on the slide guide 3, and a driver base 6 is mounted on the second sliders 4b, 4b via a second mounting tool 5b fixed over them. A chuck base 7 extending in parallel is positioned and fixed below the chuck base 7. A drive motor 9 is fixed to the driver base 6 via a motor mounting base 8 with its drive shaft 9a downward, and the drive shaft 9a is connected to the slide guide 3 via a transmission gear mechanism 10. Driver bits 11 extending in parallel are connected so as to rotate together. The chuck base 7 has a mounting plate 12 on the lower surface thereof.
The chuck unit 13 is fixed via. The chuck unit 13 is provided with a chuck body 13a through which the driver bit 11 can be inserted and a rotatably rotatably supported by the chuck body 13a, and a spring (not shown) closes the tip to close the moving path of the driver bit 11. It is composed of a pair of biased chuck claws 13b, and one screw is air-fed from a supply hose (not shown) to a screw holding hole (not shown) formed by the pair of chuck claws 13b. Is configured. Cam followers 15 and 15a are rotatably attached to the driver base 6 and the chuck base 7, respectively, via a support 14 so as to project in the extending direction thereof.
5a is configured to reach the inside of the column 2 through the notch window 2a cut in the column 2 and fit into the circumferential cam grooves 16a and 17a of the rotating rollers 16 and 17 to be described later to roll. .

On the other hand, a roller shaft 18 is erected and rotatably attached to the upper portion of the column 2 so as to be rotated by the rotation of a rotary shaft 19 described later. The roller shaft 18
The rotary rollers 16 and 17 are fixed at predetermined positions at positions corresponding to the driver table 6 and the chuck table 7, respectively, and the rotary rollers 16 and 17 are rotated at a predetermined speed as the roller shaft 18 rotates. It is configured to rotate once. Further, as shown in FIG. 3A, the rotating roller 16 on the driver base 6 side is provided with a descending curve portion having a predetermined descending stroke, an ascending curve portion having a predetermined ascending stroke, and a straight portion having a predetermined length on the outer periphery thereof. The continuous circumferential cam groove 16a provided is cut down, and the descending stroke of this descending curve portion is configured to be sufficiently longer and draw a gentle curve than the circumferential cam groove 17a on the chuck base 7 side described later. Has been done. Further, the straight portion is configured to wait at that position until the driver base 6 reaches the lowermost position and the rear driver bit 11 completes the tightening. Moreover, the circumferential cam groove
16a includes a cam follower 1 fixed to the driver base 6 side.
5 is fitted so that the cam follower 15 is pushed downward when rolling along the descending curve portion with the rotation of the rotating roller 16, and is pushed upward when rolling along the ascending curve portion. It is configured to be pushed up.

Further, as shown in FIG. 3b, the rotary roller 17 on the side of the chuck base 7 has a descending curve portion having a predetermined descending stroke, an ascending curve portion having a predetermined ascending stroke, and a linear portion having a constant length on the outer periphery thereof. And a continuous circumferential cam groove 17a is formed, and the descending stroke of the descending curve portion is formed to have a length necessary to bring the tip of the chuck unit 13 closer to the work. Further, the linear portion is configured to wait at that position until the driver bit 11 completes the tightening after the chuck base 7 reaches the lowermost position. Further, the rising curve portion is formed so that the starting time of the rising stroke is earlier than the circumferential cam groove 16a on the driver base 6 side, and when the rising stroke on the driver base 6 side is started, it is almost half. It is formed so as to reach a position where it ascends and returns. Further, the ascending curve portion of the circumferential cam groove 17a on the chuck base 7 side has a straight line portion, and the chuck base 7 is temporarily stopped during the ascending and waits for the driver base 6 to ascend, and then re-ascends to the driver base. 6 and the chuck base 7 are configured to return to their original positions.

On the other hand, as shown in FIG. 2, a rotary shaft 19 extending in a direction intersecting with the roller shaft 18 is rotatably arranged below the roller shaft 18, and one end of the rotary shaft 19 is automatically screwed through an electromagnetic clutch 19b. The driven sprocket 19a for transmitting the rotation from the external drive source of the carrying device 22 to which 1 is attached is fixed, and the rotation shaft 19 is rotated by the rotation of the external drive source. The rotating shaft 19 and the roller shaft 18 are connected via a bevel gear mechanism 20 which is an example of a rotation transmitting mechanism, and the rotation of the rotating shaft 19 is transmitted to the roller shaft 18. In addition, the pulse encoder 21 is connected to the other end of the rotary shaft 19, detects the rotation angle of the rotary shaft 19, and detects one rotation of the roller shaft 18 from the rotation angle of the rotary shaft 19. When 18 turns once, electromagnetic clutch
It is configured to shut off the rotation of the rotary shaft 19 by shutting off 19b. The external drive source may be another rotary drive source.

In the above automatic screw tightener, when the work start command signal is received, the rotation from the external drive source is transmitted to the rotation shaft 19, and the roller shaft 18 rotates one rotation. While the roller shaft 18 makes one rotation, the rotating roller 1 is rotated as the roller shaft 18 rotates.
6, 17 rotate together, and cam followers 15, 15a attached to the driver table 6 side and the chuck table 7 side are cut around the outer circumference of the rotating rollers 16, 17 as the rotating rollers 16, 17 rotate. It rolls on the descending curve portion of the circumferential cam grooves 16a, 17a. Therefore, the cam followers 15, 15a receive a force in the downward pressing direction, and the driver base 6 and the chuck base 7 descend. Moreover, the rotating roller 16 on the driver base 6 side
Since the predetermined lowering stroke of the descending curve portion of the circumferential cam groove 16a of is longer than the lowering stroke of the circumferential cam groove 17a of the rotating roller 17 on the chuck base 7 side, and the inclination thereof is gentle, the chuck base 7 is Even after the stop, the driver base 6 descends to reach the lowest position, and waits at that position for a while to secure the screw tightening time. Therefore, the driver bit 11 held by the driver base 6 moves forward with respect to the chuck unit 13 fixed on the chuck base 7, and the chuck claws 13b
A screw (not shown) held by the screw can be brought into contact with the screw and pushed out from the chuck claw 13b to tighten the screw at a predetermined position.

When the screw tightening is completed, the drive motor 9 stops, while the chuck table 7 and the driver table 6 stop at that position for a while, and then the cam follower 15a on the chuck table 7 side moves to the rising curve portion of the circumferential cam groove 17a. After the chuck base 7 rolls up and the chuck base 7 rises with respect to the driver base 6,
And the driver base 6 is raised and returned to prepare for the next work.

[Advantages of the Invention] As described above, according to the present invention, a driver follower holding a driver bit and a chuck stand to which a chuck unit holding a screw is fixed are attached to a cam follower and a circumferential cam to which the cam follower is fitted. It is reciprocated by a reciprocating drive source composed of a rotating roller having a groove, and the roller shaft to which the rotating roller is fixed is extended downward, and the rotation of the rotating shaft which is positioned below and orthogonal to the roller shaft is transmitted via a rotation transmission mechanism. Since the driven sprocket is configured to rotate integrally with one end of the rotating shaft, the power source of the reciprocating drive source rotates the external device such as a carrier device to which the automatic screw tightener of the present application is attached. It can be used as part of the rotation of the drive source, and can be reliably synchronized with external equipment in response to the operating speed of external equipment, making it extremely flexible. There is an advantage that a business system can be established and an inexpensive device can be provided.

[Brief description of drawings]

1 is a longitudinal sectional view of an essential part for explaining the whole of the present invention, FIG. 2 is a sectional view of an essential part taken along the line AA of FIG. 1, and FIGS. 3a and 3b are discs according to the present invention. FIG. 4 is a development view of the circumferential cam groove of the cam, and FIG. 4 is a partially cutaway view of the conventional example. 1 ... Automatic screw tightener, 1a ... base, 2 ... column, 2a ... notch window, 3 ... slide guide, 4a ... first slider, 4b ... second slider, 5a ... first Fixture, 5b ... Second fixture, 6 ... Driver base, 7 ... Chuck base, 8 ... Motor mount, 9 ... Drive motor, 9a ... Drive shaft, 10 ... Transmission gear mechanism, 11 ...... Driver bit, 12 …… Mounting plate, 13 …… Chuck unit, 13a …… Chuck body, 13b …… Chuck claw, 14 …… Supporting tool, 15, 15a …… Cam follower, 16 …… Rotary roller, 16a… … Circumferential cam groove, 17 …… Rotary roller, 17a …… Circumferential cam groove, 18 …… Roller shaft, 19 …… Rotary shaft, 19a …… Driven sprocket, 19b …… Electromagnetic clutch, 20 …… Bevel gear mechanism, 21 …… Pulse encoder, 22 …… Transport device, 23 …… Rotary drive source,

Claims (1)

[Claims] 1. A driver pedestal and a chuck pedestal are movably guided along a column at predetermined intervals, and a driver bit which is rotated by a rotation of a drive motor is attached to the driver pedestal, and the driver is attached to the chuck pedestal. The chuck unit, which is composed of a chuck body through which a bit is inserted and a pair of chuck claws rotatably mounted on the chuck body and urged so as to close the moving path of the driver bit by closing a tip by a spring, is fixed, A roller shaft extending in parallel with the driver bit is rotatably arranged, and a rotating roller is arranged on this roller shaft so as to rotate integrally with the driver base and the chuck base, respectively. A descending curve part having a predetermined descending stroke and an ascending curve having a predetermined ascending stroke on the outer circumference of each rotating roller. The circumferential cam groove consisting of the line part is cut, and the cam followers that fit into these circumferential cam grooves are attached to the driver stand side and the chuck stand side, and the downward stroke of the circumferential cam groove on the driver stand side is chucked. In an automatic screw tightener that is longer than the lowering stroke of the circumferential cam groove on the platform side, the roller shaft is made to project from the lower part of the column, while the rotating shaft extending in the direction intersecting with it is rotatably arranged below the roller shaft. An automatic screw tightener is characterized in that the roller shaft and the rotary shaft are connected via a rotation transmission mechanism, and a driven sprocket that rotates integrally with the rotary shaft is attached to one end of the rotary shaft.