JPH0644620Y2 - Article gripping device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an article gripping device, and more particularly to an article gripping device suitable for holding a hole of a roll-shaped article.

(Prior Art) Japanese Patent Application Laid-Open No. Sho 58-58 is a conventional technology related to an article gripping device.
The ones described in JP-A-155192 and JP-A-58-206387 are known.

To explain the conventional technique described in the above publication, Japanese Patent Laid-Open No. 155192/1983 describes a robot hand having a palm with an industrial camera as a visual device.

Further, in Japanese Patent Laid-Open No. 58-206387, a plurality of detection units provided in the working end of the robot for detecting the existence of a working subregion located in the vicinity of the target position of the working end are within a predetermined area. Describes a position correction device for a robot, which is provided with detection bodies distributed in a fixed array.

(Problems to be Solved by the Invention) However, the above-described conventional techniques have the following problems.

That is, since the robot hand described in Japanese Patent Laid-Open No. 58-155192 uses an industrial camera, the device is expensive and the cost is high.

Further, in the robot position correcting device described in JP-A-58-206387, a detecting section composed of an optical fiber type photoelectric switch is provided on the chuck claw, and the detecting section moves together with the chuck claw. Therefore, the position of the detection unit may be displaced, and the positioning accuracy may deteriorate. Further, since the optical fiber is moved, the life of the optical fiber is short and the processing and assembling of the claws are complicated.

Therefore, an object of the present invention is to provide a plurality of detectors fixedly installed at substantially constant intervals on a circumference having a diameter smaller than the outer diameter of the above-mentioned claws, in addition to the claws. An object of the present invention is to provide a gripping device for an article that can quickly confirm the alignment state between the center of the nail and the center of the hole of the article.

(Means for Solving the Problem) The present invention relates to an article gripping device for gripping a hole of an article by a plurality of claws that can move in the radial direction, and when the claw is closed, separately from the claw. A plurality of detectors fixedly installed at substantially constant intervals on concentric circles having a diameter smaller than the outer diameter of the grip portion of the claw, and between the claws. The above object is achieved by providing a gripping device for an article.

(Embodiment) An embodiment of a gripping device for articles according to the present invention will be described below.

FIG. 5 is a plan view showing a roll-shaped article gripping device as an embodiment of the article gripping device of the present invention, and FIG. 6 is a front view thereof (a part of the roll-shaped article is omitted for illustration. )so,
In these drawings, (1) is a gripping hand for gripping a roll-shaped article (5), which is fixedly installed at substantially constant intervals on a circumference having a diameter smaller than the outer diameter of the claw (11).
It is equipped with one detector (19). Further, (2) is a detection device for detecting the center of the hole of the roll-shaped article (5),
(3) is an articulated robot in which the gripping hand (1) and the detection device (2) are fixedly installed at a wrist flange portion (31) with a certain distance. Further, (4) is a turntable for rotating the pallet (6) on which the roll-shaped article (5) is placed.

The respective parts in the embodiment will be described in detail. The gripping hand (1) grips the hole (51) of the roll-shaped article (5) by three claws (11) that are opened and closed in parallel in the radial direction. As shown in FIG. 1 (the upper side of the center line shows the state in which the claw (11) is closed and the lower side shows the state in which the claw (11) is opened). , 3 claws (11) that can move radially, each claw (11)
Gripping an article by three link mechanisms (12) corresponding to respective claws (11) that move in the radial direction, a drive unit (13) that expands and contracts the link mechanism (12) in the radial direction, and a link mechanism (12) The compression spring (14) biases in the direction, three detectors (19) fixedly installed on the shaft (15) via the detector mounting bracket (19a), and the like. Each of the claws (11) is linked via a claw mounting bracket (11a) to the claw mounting bracket (11a) at one end and to the shaft (15) at the other end by a link (12a), (12b). And a link mechanism (12) consisting of a link (12c) having one end connected to the claw mounting bracket (11a) and the other end connected to the slide bracket (16a) by a pin. In addition, the drive unit (13) moves the slide bracket (16a) by the air cylinder (17) via the cylinder bracket (16b) and the rod (16), thereby linking the link mechanism (12).
Is designed to expand and contract in the radial direction, and when the air cylinder (17) is in the off state, the compression spring (14) does not urge the three pawls (11) in a direction to expand each other. There is. The link mechanism (12) and the drive section (13) are arranged so as to surround the shaft (15). The shaft (15) and the air cylinder (17) are fixed to the fixing bracket (18). Further, (17a) is a cylinder rod of the air cylinder (17). Further, an optical fiber type photoelectric switch is suitable as the detector (19), and the light emitting and receiving tip portion (19b) thereof is near the tip portion of the claw (11) and the claw (11) when the claw (11) is closed. ) Gripping part (11
It is fixedly installed on a concentric circle having a diameter slightly smaller than the outer diameter of b) and located between the claws (11). Further, (19c) is an optical fiber, and the shaft (15)
It is connected to an amplifier (not shown) via the hollow part of.

When gripping the roll-shaped article (5), the gripping hand (1) is moved to the upper part of the hole (51) and the three detectors (19) are used to move the gripping hand (1). Center and hole (51)
Check if the center of the is aligned, and if aligned, with the claw (11) closed,
After inserting the gripping hand (1) into the hole (51) substantially vertically, the roll-shaped article (5) can be gripped by opening the claw (11). In addition, it is preferable that silicone rubber or the like is attached to the outer periphery of the claw (11) to prevent the claw (11) and the roll-shaped article (5) from slipping.

Further, the detection device (2) includes four detectors (21) arranged at substantially constant intervals on the circumference having a diameter smaller than the inner diameter of the hole (51) to be detected. . That is, the eighth to
As shown in Fig. 13, the diameters of circles orthogonal to each other X axis, Y
A detector (21) is provided at each intersection of the axis and the circle. The diameter of the circle is slightly smaller than the diameter of the hole (51) to be detected (for example, the inner diameter of the hole (51) is 48 to 51 mm).
In the case of, the diameter of the circle in which the detector (21) is arranged is 45 mm,
When the inner diameter of the hole (51) is 73 to 76 mm, the diameter of the circle in which the detector (21) is arranged is preferably 70 mm). A laser light reflection type photo switch is suitable as the detector (21).

Further, as shown in FIG. 7, the articulated robot (3) has a fixed gripping hand (1) and a detection device (2) on a wrist flange portion (31) via a bracket (32). It is fixedly installed over a distance. The gripping hand (1)
The eccentric direction between the sensor and the detector (2) is the wrist flange (31).
Since the detection device (2) detects the hole (51) of the roll-shaped article (5) and moves the gripping hand (1) in the eccentric direction by the fixed distance, The hand (1) can be moved to the position of the hole (51) of the roll-shaped article (5). In addition, the gripping device for the roll-shaped article shown in FIG.
Corresponding to 1), it is equipped with two sets of detectors (2) each consisting of four detectors (21a), ..., (21b) ..

The roll-shaped article (5) is a core (paper tube) wound with a web of paper, non-woven fabric, or the like.

Next, the manner of gripping a roll-shaped article by the above-described gripping apparatus for a roll-shaped article, which is performed using the gripping apparatus for an article of the present invention, will be described.

In the gripping device for a roll-shaped article of the present embodiment, any one of the four detectors (21) described above is placed inside the hole (51) of the roll-shaped article (5). By moving the wrist flange portion (31) until the position is detected, the detecting device (2) is moved in a substantially spiral shape, and any one of the detectors (21) is placed inside the hole portion (51). After detecting the position, the detector (2) that detects the position inside the hole (51) until all the detectors (21) detect the position inside the hole (51).
According to 1), the detection device (2) is moved in a predetermined direction by a predetermined amount to align the center of the detection device (2) with the center of the hole (51). After detecting the center position of the hole (51) by the wrist flange (31) according to the angle of the wrist flange (31) and the eccentricity between the gripping hand (1) and the detection device (2), etc.
(11) of the gripping hand (1) by moving the
Is moved to the position of the hole (51), and the hole (51) is grasped by the claw (11) of the grasping hand (1).

As shown in FIGS. 5 to 6, a plurality of roll-shaped articles (5) stacked in four places on the pallet (6) are placed on the turntable (4) and a command to hold the roll-shaped articles (5) is given. Then, the search for the hole (51) of the roll-shaped article (5) starts.

First, in order to confirm the presence or absence of the roll-shaped article (5), the maximum placement error from the standard placement position (point AO) (see FIG. 15) of the hole (51) of the roll-shaped article (5) The detection device (2) is moved to a point separated as described above, and at that position, one or more detectors (21) among the four detectors (21) detect the reflected light from the roll-shaped article (5). Do (turn on)
It is confirmed whether or not. If at least one detector (21) is turned on, the presence of the rolled article (5) is confirmed. If all the detectors (21) do not detect the reflected light (OFF), it is confirmed that the roll-shaped article (5) is absent, so an abnormal command is issued and the system stands by.

When the presence of the roll-shaped article (5) is confirmed, the detection device (2) is moved to the standard mounting position (point AO) of the hole (51) of the roll-shaped article (5). At this time, if the roll-shaped article (5) is placed without error, four detectors (2
In 1), all are turned off and the alignment is completed.
If the roll-shaped article (5) is placed with an error, at least one of the four detectors (21) is turned on. If the roll-shaped article (5) is placed with a slight error and at least one detector (21) is off, the roll-shaped article (5) is aligned as will be described later.

If all four detectors (21) are turned on,
When the placement error of the roll-shaped article (5) is large, all of the four detectors (21) have holes (51) in the roll-shaped article (5).
This is when the position inside is not detected. In this case, the center of the detecting device (2) and the center of the hole (51) are aligned as shown in the flowchart of FIG.

That is, when all four detectors (21) are turned on, the wrist flange (31) is moved to move the points AO (XO, YO) and A11 (XO + ΔX, YO) as shown in FIG. ) Is moved so that it is connected by a straight line, and if none of the four detectors (21) is turned off in the middle, the detection device (2) is further turned on. A11, point A12 (XO, YO
+ ΔY), point A13 (XO-ΔX, YO), point A14 (XO, YO-Δ
If the detector (2) is moved so as to connect Y) with an arc and none of the four detectors (21) is turned off in the middle, A21 (XO + 2ΔX, YO), A22 (X
O, YO + 2ΔY), A23 (XO-2ΔX, YO), A24 (XO, YO-
2ΔY) ... and expand the arc in a spiral shape (concentric circle). If any one of the detectors (21) is turned off during the movement of the detection device (2), the detection device (2) stops the above-mentioned substantially spiral movement. That is, when the hole (51) of the rolled article (5) is at the position 51α, the detection device (2)
While one is moving from the point A31 to the point A32, one detector (21) is turned off, and then the detection device (2) stops the substantially spiral movement. In addition, the hole (51) of the roll-shaped article (5) has 51β
In the position of, the detection device (2) moves from the point A33 to the point A.
While going to 34, one detector (21) is turned off, at which time the detector (2) ceases to move in a generally spiral fashion. still,
The above-mentioned substantially spiral movement path is point A11, point A12, point A13.
Arc connecting points, point A13, point A14, arc connecting points A21, point A21,
Arc connecting point A22 and point A23, arc connecting point A23, point A24 and point A31, arc connecting point A31, point A32 and point A33, point A33 and point A3
It consists of a combination of 4, arcs connecting points A41, and so on.

As illustrated in FIGS. 8 to 12, if any one of the four detectors (21) is turned off, all the detectors (21) are turned off. , Detectors (2)
According to the table, either in the X-axis direction or the Y-axis direction, or in both the X-axis direction and the Y-axis direction (combined vector direction of the X-axis and the Y-axis) by a minute distance Δx, Δy, respectively (for example, , In FIG. 8, the detection device (2) is moved in the Y-axis direction by -Δy), and the four detectors (21) after the movement are turned on or off, respectively.
The detecting device (2) is again moved according to the table, and thereafter, the moving and detecting are repeated in the same manner, and as shown in FIG. 13, the four detecting devices (21) are repeated until all of them are turned off. The center of 2) and the center of the hole (51) are aligned. If the inner diameter of the hole (51) is 48 to 51 mm, Δ
It is preferable that x and Δy are about 3 mm, respectively.

After the center of the hole (51) is detected by aligning the center of the detection device (2) with the center of the hole (51) as described above, the angle and grip of the wrist flange (31) are grasped. According to the eccentricity of the hand (1) and the detection device (2), the wrist flange part (31) is moved, and the gripping hand (1) is moved to the position where the detected hole part (51) exists, and the gripping part is gripped. With the three detectors (19) provided on the hand (1), it is confirmed whether or not the center of the gripping hand (1) and the center of the hole (51) are accurately aligned, and they are aligned. If all three detectors (19) detect the hole (51), that is, no reflected light is detected (OFF),
Since the gripping hand (1) can be inserted into the hole (51), the gripping hand (1) is lowered and the gripping hand (1) is inserted into the hole (5).
It is inserted almost vertically into 1) and the hole (51) is gripped by the claw (11) of the gripping hand (1). It should be noted that when there is a positional deviation between the center of the gripping hand (1) and the center of the hole (51), that is, when any of the detectors (19) is detecting the reflected light (ON), it is abnormal. Give a command and wait.

As shown in the upper side of the center line in FIG. 1, the claw (11) of the gripping hand (1) is turned on by the solenoid (not shown) of the air valve, the air enters the air cylinder (17), and the cylinder rod (17a). ) Is at the right end, and the spring (14) is compressed, so that the claw (11) is inserted into the hole (51) when the claw (11) is closed. When the solenoid of the air valve is turned off and the air of the air cylinder (17) is turned off, the slide bracket (16a) is moved by the repulsive force of the spring (14) onto the shaft ( Slide to the left along 15), and the link (12c) expands the claw mounting bracket (11a) and claw (11).

At this time, each link (12
Since a), (12b), and (12c) correspond to the three claws (11), respectively, the three claws (11) simultaneously open in the radial direction in parallel with each other to open the roll-shaped article (5). It is gripped by the repulsive force of the spring (14). Therefore, even if the power source or the air source is cut off, the grasped roll-shaped article (5) can be kept grasped without dropping and is safe. When closing the pawl (11), turn on the solenoid of the air valve and put the air into the air cylinder (17). The cylinder rod (17a) overcomes the repulsive force of the spring (14) and moves to the right. 16a) is the shaft (1
Slide to the right along 5) and close the pawl mounting bracket (11a) and pawl (11) with the link (12c).

Although the embodiment of the device for gripping an article of the present invention and the gripping mode of a roll-shaped product performed using the device for gripping an article of the present invention have been described above, the invention is not limited thereto. For example, two or four or more claws (11) and detectors (19) may be provided in the gripping hand.

A laser light reflection type photo switch was used as the detector (21), but the work was made of metal and the detection device (2)
If can be sufficiently approached to the work, a proximity switch may be used as the detector (21).

Further, as the detector (19), in addition to the optical fiber type photoelectric switch, a normal reflection type photoelectric tube, a laser light reflection type photo switch or a proximity switch when the work is made of metal can be adopted.

Further, as shown in FIG. 15, instead of moving the detection device (2) in a substantially concentric shape, as shown in FIG.
Starting from BO (XO, YO), B11 (XO ＋ ΔX, YO), B12 (XO ＋)
ΔX, YO + ΔY), B13 (XO, YO + ΔY), B14 (XO-ΔX, Y)
O + ΔY), B15 (XO-ΔX, YO), B16 (XO-ΔX, YO-Δ
Y), B17 (XO, YO-ΔY), B18 (XO + 2ΔX, Y-ΔY)
The detection device (2) may be moved in a straight line spiral shape in which the points are connected by straight lines.

When the inner diameter of the hole (51) is 48 to 51 mm, ΔX, Δ
It is preferable that each Y is about 30 mm.

(Effects of the Invention) As described above, the gripping device for articles according to the present invention,
Detecting the alignment state between the center of the claw and the center of the hole by including a plurality of detectors fixedly installed at substantially constant intervals on the circumference having a diameter smaller than the outer diameter of the claw. You can check with high accuracy.

[Brief description of drawings]

FIG. 1 is a front view (partially shown in cross section) showing an embodiment of a gripping device for articles of the present invention, and FIGS. 2 to 4 are S-S views and TT views of FIG. FIG. 5, a U-U view, FIG. 5 is a plan view showing a roll-shaped article gripping device as an embodiment of the article gripping device of the present invention, and FIG. 6 is a front view thereof (a part of the roll-shaped article 7 is a bottom view showing the vicinity of the detecting device, FIGS. 8 to 13 are explanatory views showing center alignment as a gripping mode of a roll-shaped article, and FIG. The flowchart, FIG. 15 is an explanatory view showing the movement route of the detection device, and FIG. 16 is an explanatory diagram showing another embodiment of the movement route of the detection device. (5): (roll-shaped) article, (11): claw (12): link mechanism, (13): drive part (14): (compression) spring, (19): detector (51): hole part

Continuation of the front page (56) References JP-A-61-14882 (JP, A) JP-A-58-206387 (JP, A) Actually opened 60-53490 (JP, U) Actual-opened Sho-58-184290 (JP , U)

Claims (1)

[Scope of utility model registration request] 1. An article gripping device for gripping a hole of an article by a plurality of claws that can move in a radial direction, and an outer diameter of the claw grip when the claw is closed, separately from the claw. An apparatus for gripping an article, comprising a plurality of detectors fixedly installed at substantially constant intervals on concentric circles having a smaller diameter and between the claws.