JPS6161785A - Wrist structure of industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a wrist structure for an industrial robot, and more specifically, a wrist provided at the tip of an arm imparts a required synthetic motion (so-called block motion) to the hand. , the various handled articles held by the hand are moved at a speed synchronized with the conveyance speed of the conveyor (for example, a belt conveyor), and in the middle of the movement, the holding of the articles is released, thereby The present invention relates to a wrist structure that allows articles to be slowly transferred to a fixed position on a carrier.

Industrial robots have been introduced to automated product assembly lines, welding processing lines, painting lines, etc. in factories, and have achieved steady results. In addition, as a recent trend, industrial robots are being used on packaging lines for various products, greatly contributing to improving the efficiency of packaging operations.

This robot dedicated to the packaging line, for example, holds various handled items collected at an item collection station with its hands and then rotates its arm to place the items on a conveyor such as a belt conveyor or packet conveyor located close to the station. 6 However, conventional packaging robots have the following drawbacks when transferring the handled items held in their hands onto a conveyor such as a belt conveyor. . In other words, ■I/I
) Since there is inevitably a head difference between the conveyor and the hand, the falling impact when discharging the handled article toward the conveyor is large, and there is a risk of damaging the handled article. ■Also, when the conveyor moves continuously (not intermittently), the difference in movement between the handled article and the conveyor may cause the handled article to collapse on the conveyor. , it becomes difficult to place it in a fixed position.

The present invention was devised in view of the current state of robots used along such packaging lines, and is capable of moving various handled items held by hands at a speed synchronized with the conveyance speed of a conveyor. While following the movement, release the hold on the object in the process.

It is an object of the present invention to eliminate the fear of damage to the handled articles and collapse of the cargo by configuring the handled articles to be slowly transferred to a predetermined position on the carrier.

In order to achieve this object, the wrist structure of an industrial robot according to the present invention includes: a substrate rotatably supported at the tip of an arm of the robot; a pair of rotating disks rotatably disposed adjacent to the substrate; a driving source for rotationally driving the rotating disks of the pair in the same direction synchronously; a connecting member having each end pivotally connected to the pair of rotating disks via bearings; and a connecting member connected to the connecting member. 4. Let T be an enemy composed of a hand of the required shape.

Next, the wrist structure of the industrial robot 1 according to the present invention will be explained in detail below by citing a preferred embodiment and referring to the attached drawings. Fig. 1 shows the cover of the wrist structure according to the present invention. 2 is a plan view of the wrist structure shown in FIG. 1, and FIG. 3 is a partially transparent perspective view showing a schematic configuration of the wrist structure. In FIG. An arm of a robot body (not shown) is shown, and a flat board I2 is rotatably supported vertically at the tip of this arm 10. That is, as shown in FIG. 14 and 16 are fixed, and a rotary shaft 18 is rotatably supported vertically on these bearings, and the rotary shaft 1
A vertical board 12 is attached to the lower end of the board 8 via a bracket 20. A worm wheel 22 is fixed horizontally to the upper end of the rotating shaft 18, and as shown in FIG. It is designed to be driven in rotation. This DC servo motor 24 is of a type that integrally incorporates a tacho generator and a pulse encoder, and a signal from the tacho generator is sent to a motor driver provided in a control section (not shown), and a signal from the pulse encoder is sent to a motor driver provided in a control section (not shown). are fed back to the encoder unit respectively, and the D
It is configured to digitally servo control the appropriate rotation speed of the C servo motor 24. The horizontal rotation may be a rotation in one direction or a reciprocating rotation at a predetermined central angle, or may be structured to provide a bending motion and a swinging motion of the wrist.

A pair of rotating disks 26 and 28 are rotatably arranged adjacent to each other on the vertical substrate 12, and the rotating disks 26 and 28 are synchronously rotated in the same direction by an appropriate drive source 30.
In other words, as shown in FIG. The tip of the fixed shaft projects at right angles in front of the substrate 12.

At the tips of the fixed shafts 32 and 34, there are bearings 40° and 40°, respectively.
2 are mounted in a corresponding manner, and spur gears 44 and 46 are respectively rotatably mounted on the bearings 40 and 42. 6 The spur gears 44 and 46 are adjacent to each other with a required spacing,
It is designed to mesh with a pinion 48 placed between both gears. The pinion 48 is connected to a drive source 30 such as an electric motor disposed on the back side of the vertical base plate 12, and under the meshing action of the pinion and the spur gear, the spur gear 44.4
A rotary disk 26 (28) is fixed coaxially to the front surface of the spur gear 44 (46) through a series of bolts 50. be. The diameter of this rotating disk 26 (28) is set slightly smaller than the diameter of the corresponding spur gear 44 (46), and as shown in FIG. In this example, arc-shaped through grooves 52 (four in this embodiment) are formed that form a predetermined central angle in the circumferential direction. By inserting the bolt 50 through the arcuate groove 52, the rotating disk 26 (28) is fixed to the corresponding spur gear 44 (46). At this time, the rotating disk 26 (28)
The rotation can be adjusted in the circumferential direction relative to the spur gear 44 (46) by the length of .

Next, a connecting member 54 having a shape as shown in FIG. A hand 60 having a desired shape is connected to 54. That is, as shown in FIG. 2, one end of a fixed shaft 62 (64) is vertically fixed to an eccentric position of the rotating disk 26 (28) by means such as welding, and the other end of the fixed shaft is fixed vertically to an eccentric position of the rotating disk 26 (28). Board 2
It protrudes in front of 6 (28). Furthermore, bearings 56 (58) are fitted into both ends of the connecting member 54 having the shape shown in the figure, allowing relative rotation. 66 (68
) is tightened and fixed. One of the through holes 69 in the connecting member 54 into which the bearing 56 is inserted has an oval shape, as can be seen from FIG. It achieves a rotation. Therefore, according to this configuration, when the pinion 48 and the spur gear 44 (46) are meshed and driven by the drive source 30, the pair of rotating disks 26, 28 synchronously rotate in the same direction, and the connecting member 54 are shown in Figure 4(a)~
It is understood that a synthetic motion (so-called block motion) following the trajectory shown in (d) is performed.6 The connecting member 54 is equipped with a hand 601 of the most appropriate type depending on its use, such as a gripper, finger, or other vacuum cup. It will be installed. In this embodiment, a support plate 70 is fixed perpendicularly to the connecting member 54 via bolts 72, and a rectangular frame plate 74 is fixed to the lower end of this hanging support plate 70. As shown in FIGS. 2 and 3, six vacuum cups 76 are attached to the lower surface of the frame plate 74, and the vacuum cups 76 are communicatively connected to a vacuum suction source (not shown). Note that the hand 60 is not limited to this vacuum cup, and it goes without saying that various types of grippers such as claw-type grippers and multi-fingered fingers can be used depending on the purpose of use.

Next, regarding the wrist structure of the industrial robot according to the present invention configured as described above, an example of its operation when installed on a packaging line will be explained with reference to FIG. 5 and FIGS. 4(a) to (d). do. The packaging line shown in plan view in Figure 5 includes:
Each conveyor 78,80 consisting of two parallel conveyors is arranged, one of which is the packet conveyor 7.
Close to 8.

An industrial robot 82 equipped with a wrist structure according to the present invention is provided. Also, the other conveyor, the alignment conveyor 8o
In the sorting conveyor 84 installed on the upstream side, the handled articles 86 (for example, carton boxes) arrive at predetermined time intervals and accumulate in large quantities near the end of the sorting conveyor 80. It is now stored. If this place where a large amount of handled items 86 are accumulated and stored is conveniently called a workstation, the arm 10 of the industrial robot I~ used in this application will be located at an appropriate position between the workstation and the packet conveyor 78. It is set to be long enough to tie. Then, the robot arm according to the present invention captures the timing when the handled articles 86 conveyed to the alignment conveyor 80 are stored in two rows of three articles (total six articles) at the workstation as shown in FIG. 10 arrives on the workstation and hand 6
．． The six vacuum cups 76 provided at 0 attract and hold the respective articles 86 to be handled, and then the arm 10 is horizontally swung toward the packet conveyor 78.

It is assumed that the inter-row width (center-to-center dimension) Wt of the objects 86 to be handled stored in units of three on the workstation is set in advance to match the pitch of each packet of the packet conveyor 78. .

FIG. 4(a) shows an initial state in which the article 86 held by the hand 60 is brought above the packet conveyor 78 by rotating the arm "0". That is, the connecting member 54 connected to the rotating disks 26 and 28 is stopped at the top dead center, and the connecting member 54 is attached via the support plate 70 (= J-shaped hand 60 is configured). The articles 86 to be handled (total of 6 items) are held by suction in the 6 vacuum cups 76, respectively, and are placed above the packet conveyor 78.Next, the drive source 30 is rotated to connect the pinion 48 and When the spur gears 44 and 46 are meshed and driven, the pair of rotating disks 26 and 28 rotate clockwise synchronously, and the connecting member 54 and the vacuum cup 76
The article 86 to be handled, which is held at 1, starts to descend as shown in FIG. 4(b), and the head difference between the article 86 and the packet conveyor 78 is reduced to L. This head further decreases as the pair of rotating disks 26, 28 rotate, and finally, as shown in FIG. 4(c), the connecting member 5'4 reaches the bottom dead center. At this time, the head difference between the handled article 86 held in the vacuum cup 76 and the packet conveyor 78 becomes zero (0), and if the vacuum of the vacuum cup 76 is released at this timing, the handled article 86 will be transferred to the hand 6.
0 is released, and the transfer of the article 86 to be handled onto the packet conveyor 78 is completed. Note that the vacuum cup 76 and the connecting member 5 with the handled article 86 released
4 starts to rise from the bottom dead center as shown in FIG. 4(d), and after returning to the initial state shown in FIG. 4(a) again, the arm 10 rotates and moves to the work station of the alignment conveyor 80. It arrives above and waits for handling of the next article 86 to be handled.

According to the list structure of the industrial robot according to the present invention, as described with reference to FIGS. 4(a) to (d).

The series of connecting members 54 and the vacuum cup 76 can be given a synthetic motion called a block motion, thereby increasing the conveyance speed of the packet conveyor 78 by moving the various handled articles 86 held by the hand 60. It is possible to follow the flow direction at a speed synchronized with the flow direction. Then, if the holding of the handled article 86 is released in the middle of the conveyance and at the timing when the head becomes the minimum, the handled article 86 will be transferred to the packet conveyor 78.
, etc., and the fear of damage to the handled items during transfer is eliminated. Furthermore, when the carrier 78 moves continuously as shown in FIGS. 4(a) to 4(d), the handled articles 86 move at a speed synchronized with the carrier 78, so the handled articles 86 and the carrier There is no difference in kinetic inertia between the article 86 and the conveyor 78, and therefore the article 86 to be handled will not collapse on the conveyor 78, nor will it become difficult to place it in the normal position 111.

[Brief explanation of drawings]

1 is a side view of the wrist structure according to the present invention with the cover removed; FIG. 2 is a plan view of the wrist structure shown in FIG. 1;
The figure is a partially transparent perspective view showing the ring 111 & configuration of the wrist structure, and FIGS. 4(a) to 4(d) show the hand attached to the connecting member moving as a so-called block motion due to the synchronous rotation of a pair of rotating disks. FIG. 5, which is an explanatory diagram showing the execution of a synthetic motion, is a planar bar 1 showing a state in which the wrist structure of the industrial robot according to the present invention is arranged on a packaging line consisting of a belt conveyor.

Claims (1)

[Scope of Claims] A substrate pivotably supported at the tip of a robot arm, a pair of rotating disks rotatably adjacent to the substrate, and the pair of rotating disks synchronously rotating in the same direction. A wrist structure for an industrial robot comprising: a driving source; a connecting member having each end pivotally connected to the pair of rotating disks via bearings; and a hand having a desired shape connected to the connecting member.