JPH09155777A - Detecting mechanism for work holding position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rest a work in a prescribed position without employing a positioning station. SOLUTION: A work hold position detecting mechanism is so constituted that a work position detecting part 11 detecting the hold position of a work 2 held in a work holding part 10, is provided for a work carrying device 1 which carries the work holding part 10 holding the work 2 composed of a thin plate shaped glass substrate for liquid crystal and the like for example, from a feeder 6 to a resting stand 7 by the refracting operation of an arm part 9. In this case, the work position detecting part 11 is provided for the work holding part 10, and is concurrently formed out of first position detecting sensors 12 and 12 detecting the position of an end side 2a, that is, one prescribed portion of the work 2, and of a second position detecting sensor 13 which is mounted onto the arm part 9, concurrently is evacuated from the work 2 when the arm part 9 is extended, also is brought into contact with the work 2 when the arm part 9 is refracted, and thereby detects the position of a side leg 2b, that is, the other prescribed portion of the work 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding position detecting mechanism of a work transfer device which transfers a supplied work and places it at a target position. More specifically, the present invention provides:
The present invention relates to a work holding position detection mechanism that detects a work holding position by a position detection sensor.

[0002]

2. Description of the Related Art For example, one work is taken out from a feeder in which thin plate works such as glass substrates for a liquid crystal display are stacked, and is conveyed and placed at a predetermined position.
A work transfer device equipped with a scalar type robot is used. The placement of the work by the work transfer device must be accurately performed at a predetermined position. Therefore, before the work is placed at a predetermined position, it is placed on the positioning station and positioned. At the positioning station, a centering unit that has been previously centered is pressed to the side of the work to correct the position of the work to a predetermined position. Then, the position-corrected work is taken out, conveyed, and placed at a predetermined position.

[0003]

However, in the above-described work transfer apparatus, since the centering unit is pressed from the side of the work at the positioning station to perform the position correction, when performing the position correction of a large and thin plate-shaped work. This pressing causes the work to bend. For this reason,
The amount of correction of the work may be insufficient due to the bending, and the position of the work may not be accurately corrected. As a result, the work is placed at an improper position. Further, by disposing the positioning station, it becomes difficult to simplify the work transfer process and reduce the work area.

Therefore, an object of the present invention is to provide a work holding position detecting mechanism which can place a work at a predetermined position without employing a positioning station.

[0005]

In order to achieve such an object, a work holding position detecting mechanism according to a first aspect of the present invention is arranged such that a work holding portion for holding a thin plate-like work is moved from one position to another position by bending and extending an arm. In the work holding position detecting mechanism, which is provided in the work carrying device for carrying the work holding device, and which includes a work position detecting unit for detecting the holding position of the work held in the work holding unit, the work position detecting unit is provided in the work holding unit. A first position detection sensor for detecting a holding position of a predetermined portion of the work, and a first position detection sensor attached to the arm and retracting from the work when the arm extends and abutting against the work when the arm bends. The second position detection sensor detects the holding position of another predetermined portion.

Therefore, when the work holding portion holds the work, the first position detection sensor detects the holding position of a predetermined portion of the work. Then, when the arm bends while holding the work, the second position detection sensor contacts the work and detects the holding position of another predetermined portion. Therefore, the holding position of the entire work is calculated from the detection results of the first and second position detection sensors while the work holding unit holds and conveys the work. The arm is extended when the work is taken out from one position or placed in another position. At this time, since the second position detection sensor is retracted from the work, it does not interfere with the work of taking out or placing the work.

Further, in the work holding position detecting mechanism according to the present invention, the first position detecting sensor is composed of two position detecting sensors which come into contact with one side of the work to detect the position of the side.
The second position detection sensor is composed of one position detection sensor that comes into contact with the other side of the work. Therefore,
The first position detection sensor detects the position of one side of the work, and the second position detection sensor detects the position of the other side. Then, the holding position of the entire work is calculated from the results of these detections.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention will be described below in detail based on the embodiments shown in the drawings.

As shown in FIGS. 1 and 2, the work transfer device 1 is a scalar type robot and a robot 3 for holding and transferring a work 2 made of a thin glass plate for a liquid crystal display, and the robot 3. And a sliding mechanism 5 that slides 3 along the linear drive shaft 4 in the X-axis direction.
Near the work transfer device 1, a feeder 6 as one position where the works 2 are stacked and a mounting table 7 as another position for mounting the works 2 are arranged.

The robot 3 has a base portion 8 mounted on the sliding mechanism 5 and an arm portion 9 which is slidable in the Z-axis direction with respect to the base portion 8 and is rotatable about the Z-axis. And a work holding part 10 which is rotatably provided around the Z axis at the tip of the arm part 9 and holds the work 2 by suction, and a work for detecting the holding position of the work 2 held by the work holding part 10. The position detector 11 is provided.

The work position detection unit 11 is a work holding unit 1.
No. 0 and the first position detection sensors 12 and 12 for detecting the holding position of one predetermined part of the work 2 and the arm part 9.
A second position for retreating from the work 2 when the arm part 9 is extended and abutting against the work 2 when the arm part 9 is bent to detect the holding position of another predetermined part of the work 2. It is assumed to be composed of the position detection sensor 13.

The base portion 8 is a motor 15, 1 for sliding and rotating the sliding shaft 14 having the longitudinal direction in the Z-axis direction in the Z-axis direction.
5 built-in. In addition, a blower (not shown) that blows downward after the air around the base portion 8 is sucked in and purified by a filter is incorporated. The motors 15 and 15 are motors such as stepping motors whose rotation angles can be controlled.

The arm portion 9 has a base end portion fixed to the sliding shaft 14 and a first arm 16 and a second arm 17 provided at the tip end portion of the first arm 16 so as to be rotatable about the Z axis. It has and. The distance between the rotation centers of both ends of the first arm 16 and the distance between the rotation centers of both ends of the second arm 17 are
Are made equal. A motor unit 18 having an arm motor (not shown) for changing the bending angle of the first arm 16 and the second arm 17 is provided at the tip of the first arm 16. The arm motor is composed of a motor whose rotation angle can be controlled, such as a stepping motor. In the present embodiment, the arm portion 9 is provided with the two arms 16 and 17, but not limited to this, it may be provided with three or more arms.

The work holding unit 10 is attached to the tip of the second arm 17 so as to be rotatable about the Z axis.
Here, the arm motor and the work holding unit 10 are connected by, for example, a toothed belt. Here, the ratio of the number of teeth of the pulley on the arm motor side around which the toothed belt is wound and the number of teeth of the pulley fixed to the work holding unit 10 is 1: 2.
It has been.

Therefore, in this embodiment, the first arm 16 and the second arm 17 have the same length, and the ratio of the number of teeth of the pulley on the arm motor side to the number of teeth of the pulley fixed to the work holding portion 10 is large. Is 1: 2, the ratio of the amount of change in the angle of the first arm 16 to the base 8 and the amount of change in the angle between the arms 16 and 17 when the arm 9 is bent is 1: 2. In this case, the work holding unit 10 is horizontally moved so as to move toward and away from the sliding shaft 14 without changing its direction.

A second position detecting sensor 13 including a potentiometer is attached to the side of the base end of the second arm 17. The mounting position of the second position detection sensor 13 is
The position is such that the arm portion 9 comes into contact with the side edge 2b of the workpiece 2 held when the arm portion 9 is most retracted to the base portion 8 side. Thereby, the position of the side 2b can be detected. In the present embodiment, the second position detection sensor 13 is a potentiometer, but it is not limited to this and may be, for example, a limit switch or a photoelectric switch. In this case, the position of the side 2b can be calculated by detecting the angle of bending of the arm 9 when the switch comes into contact with the side 2b of the work 2 and is turned on.

Further, in this embodiment, when the second position detecting sensor 13 comes into contact with the side edge 2b of the work 2, the arm portion 9 is used.
However, the present invention is not limited to this, but may be any time as long as the arm portion 9 is bent and the work holding portion 10 is retracted from the feeder 6. In this case, it is preferable to provide a mechanism for retracting the second position detection sensor 13 from the work 2 after the second position detection sensor 13 contacts the side edge 2b before the arm part 9 is most retracted. If this mechanism is provided, the second position detection sensor 1
It is possible to avoid a situation in which the arm 3 is in contact with the work 2 and the arm portion 9 cannot be further bent, and the work holding portion 10 can be most retracted, so that the work 2 can be easily swung around the sliding shaft 14. be able to.

On the other hand, the work holding section 10 is provided with two parallel adsorption rods 10b in which a large number of adsorption holes 10a opened downward are continuously arranged in a line. First position detection sensors 12, 12 including a potentiometer and the like are attached near the base end of each suction rod 10b. The mounting position of each of the first position detection sensors 12 and 12 is the held work 2
It is located at a position where it abuts on the end side 2a of the base portion 8 side.

Further, the sliding mechanism 5 includes a linear motion shaft 4 having a longitudinal direction in the X-axis direction and a guide rod 1 parallel to the linear motion shaft 4.
A feed screw 20 made up of 9, 19 and a male screw, and a motor 2 made up of a stepping motor or the like for rotating the feed screw.
1 is provided. The guide rods 19 and 19 have a base portion 8
Lower sliders 22, 22 are slidably mounted. Further, the feed screw 20 is engaged with a screw receiver 23 formed of a female screw on the lower portion of the base portion 8. Therefore, when the feed screw 20 is rotated by the motor 21, the screw receiver 23
Is urged in the X-axis direction, and the robot 3 moves the guide rods 19, 1
9 and slides in the X-axis direction. Then, the movement distance of the robot 3 can be controlled by controlling the rotation angle of the motor 21.

A mounting table 7 is arranged apart from the feeder 6. In this embodiment, the mounting table 7 is a temporary mounting table for setting the position. However, the present invention is not limited to this, and the mounting table 7 may be configured by a device such as a conveyor or another member for mounting the work 2.

The work 2 is moved by the work transfer device 1 described above.
When picking up the paper from the feeder 6 and mounting it on the mounting table 7, the arm portion 9 is extended to suck and hold the work 2 supplied from the feeder 6. At this time, each of the first position detection sensors 12 and 12 comes into contact with the end side 2a of the work 2. Then, the sliding shaft 14 slides in the direction away from the base portion 8 to lift the work 2 together with the work holding portion 10. Here, the arm portion 9 is bent to move the work 2 in the Y-axis direction, so that the work holding portion 10 is most retracted, that is, the work holding portion 10 is farthest from the feeder 6. At this time,
The second position detection sensor 13 contacts the side 2b of the work 2. In this state, the sliding part 5 is driven to move the robot 3 to the X position.
Move in the axial direction.

By the way, the holding position of the work 2 is calculated, for example, by the following procedure while the work 2 is being conveyed. As shown in FIG. 3, each first position detection sensor 12, 1
The position / inclination of the edge 2a of the work 2 with respect to the reference position B is calculated from the detection result of 2. Then, the position / inclination of the side 2b with respect to the reference position B is calculated from the calculation result and the detection result of the second position detection sensor 13 and the condition that the end side 2a and the side 2b of the work 2 are orthogonal to each other. Further, the position of the intersection 2c of the edge 2a and the side 2b with respect to the reference position B is calculated. Therefore, the edge 2a and the side 2
The holding position of the workpiece 2 with respect to the reference position B is calculated from the inclination of b and the intersection position 2c.

Then, a correction amount from the calculated holding position to the reference position B is calculated, and a moving distance in the XY axis directions to a predetermined position to be placed and a rotation angle about the Z axis are obtained, In response to this, the drive amounts of the sliding mechanism 5 and the arm portion 9 are controlled. After the work holder 10 and the work 2 are positioned on the mounting table 7, the slide shaft 14 is slid downward to release the suction holding, so that the work 2 is mounted on the mounting table 7 at a predetermined position. It

The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in this embodiment, the work holding position detection mechanism in which the glass plate for a thin liquid crystal display is used as the work 2 is explained, but the work 2 in which other members such as a mask of a glass substrate and a wafer are used. A holding position detecting mechanism may be used.

[0025]

As is apparent from the above description, in the work holding position detecting mechanism according to the first aspect of the present invention, the work position detecting unit is provided with the first position detecting sensor provided in the work holding unit and the second position detecting unit attached to the arm. Since it is configured by the sensor, the holding position of the entire work is calculated from the detection results by the first and second position detection sensors. Therefore, the holding position of the work can be detected while the work is being conveyed from one position to another position, and the holding position can be corrected to the normal position while the work is held. Thereby, when mounting on another position, it can be accurately mounted on a predetermined position to be mounted. Therefore, the work can be placed at a predetermined position without adopting the positioning station, so that the work steps for mounting the work can be reduced and the work area can be reduced.

Further, when the arm is extended, the second position detecting sensor retracts from the work, so that it does not interfere with the work of taking out or placing the work. Therefore, when the work is taken out from one position, it is not necessary to bring the work holding part close to the work with high accuracy, and the movement of the work holding part can be easily controlled.

Further, in the work holding position detecting mechanism according to the present invention, the first position detecting sensor is composed of two detecting sensors which come into contact with one side of the work and detect the position of the side. Is composed of one detection sensor that comes into contact with the other side of the work. Therefore, since the position of one side of the work is detected by the first position detection sensor and the position of the other side is detected by the second position detection sensor,
The holding position of the entire work can be accurately calculated from the position of each side. And the effect of claim 1 can be produced.

[Brief description of the drawings]

FIG. 1 is a plan view showing an arrangement layout of a work transfer device equipped with a work holding position detection mechanism of the present invention and peripheral devices thereof.

FIG. 2 is a side view showing a work transfer device.

FIG. 3 is a plan view showing a positional relationship between a work and each position detection sensor.

[Explanation of symbols]

 1 Work Transfer Device 2 Work 2a Edge Side (One Side) 2b Side Side (Other Side) 3 Robot (Work Transfer Device) 5 Sliding Mechanism (Work Transfer Device) 6 Feeder (One Position) 7 Placement Table (Other Position) 9 arm part (arm) 10 work holding part 11 work position detection part 12 first position detection sensor (work position detection part) 13 second position detection sensor (work position detection part) 16 first arm 17 second arm

Claims (2)

[Claims] 1. A work holding unit for holding a thin plate-like work is provided in a work carrying device for carrying the work from one position to another by bending and stretching of an arm, and the work holding position of the work held by the work holding unit is set. In a work holding position detecting mechanism including a work position detecting unit for detecting, the work position detecting unit is provided in the work holding unit and detects a holding position of a predetermined portion of the work.
A position detecting sensor and a sensor which is attached to the arm and retracts from the work when the arm extends, and contacts the work when the arm bends to detect the holding position of another predetermined portion of the work. A work holding position detecting mechanism comprising a second position detecting sensor. 2. The first position detection sensor is composed of two position detection sensors that come into contact with one side of the work to detect the position of the side, and the second position detection sensor is the other side of the work. The work holding position detecting mechanism according to claim 1, comprising one position detecting sensor that abuts against the work holding position.