JPS62241691A - Attitude controller for working tool - 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 (Field of Industrial Application) The present invention relates to a machining tool posture control t11 device for maintaining a constant posture of a machining tool attached to a movable arm of an industrial robot or the like.

(Prior art) As a conventional device of this kind, Grand Duke III 57-24451
According to the above publication, a tool mounting plate is attached via a joint to the tip of a movable arm that is attached to a machine frame via a joint, and a parallel link is provided on the arm that connects the mounting plate and the machine frame. The arm and the link constitute a parallel link-type parallel ruler mechanism, and the mounting plate, and hence the processing tool attached to it, can be adjusted to the 1i! position of the arm. There are known devices that can always maintain a constant posture regardless of the length of time.

(Problem to be Solved by the Invention) There are cases where it is desired to make the movable arm telescopic in its longitudinal direction in order to expand the movement range of the processing tool, but in the parallel link type parallel ruler mechanism described above, the link Unless the tool mounting plate is extended and contracted by a separate drive source in synchronization with the extension and contraction of the arm, the posture of the tool mounting plate cannot be maintained constant, making the structure complicated and expensive.

SUMMARY OF THE INVENTION In order to solve this problem, it is an object of the present invention to provide a device with a simple structure that can maintain a constant posture of a tool mounting plate even when the movable arm extends and contracts.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a movable arm attached to the machine frame via a joint that is extendable and retractable in its longitudinal direction.
A tool mounting plate is attached to the tip of the arm via a joint, and the mounting plate is maintained in a constant posture by a parallel ruler mechanism provided between the machine frame, and the mechanism is connected to a wire cable. A pair of wire cables corresponding to a predetermined swing direction of the arm is attached to each cable locking member provided between the machine frame and the mounting plate, and the outer tube of each cable is connected to the outer tube of each cable. Wire the wires while locking each end of the li! Wire engagement portions located in the inner direction and the side are formed, and each end of the inner wire of one of the wire cables is connected to each engagement portion on one side of the swinging direction at both ends of the arm. The machine frame and the mounting plate are connected to the attachment portions through wire guide members provided at opposite positions of the attachment portions, and each end of the inner wire of the other cable is connected to both ends of the arm. The present invention is characterized in that each of the engaging portions on the other side in the swinging direction is engaged with each of the engaging portions of the machine frame and the mounting plate through wire guide members provided at opposing positions.

(Example) The illustrated example in which the present invention is applied to an industrial robot will be described below.

Referring to Figures 1 and 2, (1) shows the machine base, and (2) shows the machine frame fixed on the machine base (1), and the machine frame (2) includes a universal joint. Movable arm (4) via sekibe (3)
is set upright, and a pair of first and second cylinders (51, 52) provided between the arm (4) and the machine frame (2) allows the arm (4) to move at any arbitrary position using the joint (3) as a fulcrum. Jffi in the direction! 7
Furthermore, the arm (4) is made to be extendable and retractable in the longitudinal direction, that is, in the vertical direction.

To explain this in further detail, the arm (4) is connected to the joint (3).
), and an upper arm (4b) that is supported by the lower arm (4b) so as to be able to rise and fall, and the upper arm (4C) is provided with an elevating cylinder (4C) that stands in the lower arm (4a). The arm (4) is extended and contracted by the vertical movement of the arm (4b), and the upper arm (4b) is
As shown in FIG. 4, the lower arm (4a) is supported by the guide members (4dl (4d)) on both sides of the open part on the rails (4eH4c) on both sides of the upper arm (4b) so as to be able to rise and fall. did.

and a rotatable bracket (6+) (62) is provided on the machine frame (2) and positioned on the X-axis and Y-axis of a Cartesian coordinate system having the center of the universal joint (3) as the origin, The first and second cylinders (5+) (52) are pivotally connected to the brackets (61) (62) at their respective lower ends, and the circumference of the upper end of the lower arm (4a) in the X@force direction and Y-axis direction is Each bracket installed on the surface (7+) (72)
The piston rods of the cylinders (51) and (52) are pivotally connected to the lower arm (4a), and therefore the movable arm (4), so that the first cylinder (51) swings in the X-axis direction. 1! in any direction with the combined movement of the second cylinder (52) and the swinging motion in the Y-axis direction. The imperial order was granted.

Also, the tip of the movable arm (4), that is, the upper arm (4b
) is attached to the upper end of the tool attachment plate (9) via a joint (8) consisting of a universal joint, and a processing tool (IG) such as a welding gun can be attached to the attachment plate (9) as appropriate.

Here, the tool mounting plate (9) is maintained in a constant position, for example, in a horizontal position, by a parallel ruler mechanism (151) provided between it and the machine frame (2). The mechanism (Iv) was configured as follows using, for example, a push-pull type wire cable.

In the illustrated embodiment, since the movable arm (4) is swung in the X-axis direction and the Y@force direction, the
A pair of first wire cables (12+) (12+) for maintaining horizontality in the axial direction, and a pair of 29th wire cables (122) (12+) for maintaining horizontality in the Y@force direction.
2) and these cables (12+) (122)
is wired between the machine frame (2) and the mounting plate (9), and each end of the outer tube (12a) is connected to the machine frame (2).
and each cable locking member (13) provided on the mounting plate (9).
(IΦ, and the lower and upper ends of the arm (4), as shown in FIGS. 3 and 5, both the joints (3) (
8) located around the axis of the arm (4) connecting
Wire attachment parts (15a H2S b ) on both sides in the axial direction,
(16a) (16b) and wire attachment parts on both sides in the Y@ direction (15c) (15d), (16C) fIG d
), and the lower end of the arm (4) is attached to the machine frame (2) at the lower end (15a), (15b), (15c), (1
Each wire guide member (17a HI3 b ) (17c ) (17d
), and the arm (4) is also provided on the mounting plate (9).
(16a) (16b) (16c) (16
d) are provided with respective wire guide members (18a 1 (18b) (18CHI3 d)) each consisting of a boob arranged opposite to each other, and the pair of first wire cables (12+) (12
Attach each end of the inner wire (12a) of one cable of t) to each of the engaging portions (15a) (16
a), each guide member (17a) (1
Similarly, each end of the inner wire (12a) of the other cable is connected to each of the connecting parts (15b) and (16b) on the other side in the X-axis direction, and 2
Connect each end of the inner wire (12a) of one cable of the wire cable (122) (122) to each of the attachment parts (15c) (16c) on the − side in the Y-axis direction, and connect the inner wire (12a) of the cable according to its usage. Each end portion of the was engaged with each of the engagement portions (15d) (16dl) on the other side in the Y-axis direction.

In the illustrated example, a guide drum a9■ having two upper and lower guide grooves is attached to the center of the machine frame (2) and the tool mounting plate (9), respectively, and the first wire cable (12+) (1
21) through the inner wires (12a) (12a) of each drum a9 through one guide groove of the X@force direction side and the other wire guide members (17a) (18a),
(17tl) (18b), and the inner wire (12a) of the second wire cable (122) (122) (
12a) for each drum a! ! 1) and connect each wire guide member (17C) on the − side and the other side in the Y-axis direction.
) (18C), (17d) (18d).

In addition, in the above embodiment, each wire engaging portion (Isa)...
・・・(15d),(16a) ・−・−・(1
6d) is offset in the axial direction of the movable arm (4) with respect to the X-Y plane passing through the center of rotation of the WU (3> (8)), but this prevents the inner wire (12a) from becoming loose. In order to improve accuracy and durability, as shown in Fig. 6, each wire engagement part (15a)...
−・(15d), (16a) ・−・・−(16d
) is preferably provided on the X-Y plane. In the drawing, t2o@ indicates a mounting bracket for the wire attachment part protruding from the end plate at both the upper and lower ends of the movable arm (4), and each attachment part (I5a
) ・-・-・-(15d l, (16a) --
----(16d) was constructed.

Here, the wire engaging part (15a)... (15d
), (16a)... (16d) do not exist on the X-Y plane passing through the rotation center of each joint (3) (8), move the movable arm (4), for example, in the Y-axis direction. When one movement is made, the wire attachment parts on both sides in the X-axis direction (t5 a
) (Is b ) (16a) (16b) move along an arc trajectory centered on the X ring passing through the rotation center of each joint (3) (8), and the wire guide member (17aH17b
), (18a) (igb) and the wire attachment part (15a
1 (15b), 16a) (16b) changes, causing strength and tension in the inner wire (12a), and the horizontal accuracy of the tool mounting plate (9) in the X@force direction deteriorates, and the inner wire (12a) may be subjected to excessive tension and its durability may deteriorate. However, each engaging portion (
158)...(ISd), (16a)...
(If 16dl is provided on the X-Y plane as shown in FIG. 6, the wire anchoring portion will be on the axis perpendicular to the swinging direction of the movable arm (4) as shown in FIG. 7. A is the arm (4
) is also positioned on the axis due to the rocking of the locking portion A;
The positional relationship between the wire guide member B and the corresponding wire guide member B is kept constant, and the above-mentioned inconvenience does not occur.

(Function) To explain the function of the present invention based on the above embodiment, the movable arm (4) is swung forward in the X@ direction by, for example, the first cylinder (51) as shown by the double-dashed line in FIG. If you let
The wire engagement portion (
15a ) moves in a direction away from the wire guide member (17a) on the machine frame (2) facing it, and one first wire cable (12+) whose one end is engaged with the engagement portion (15a) The inner wire (12a) is pulled and the other end is engaged with the wire engagement part (16a) on the rear side in the X-axis direction of the upper end of the arm (4) and the wire on the tool mounting plate (9) opposite thereto. The distance from the guide member [18a) is narrowed, and the wire attachment part (15b) on the front side in the X@ direction at the lower end of the arm (4) is opposite to the machine frame (2).
As it moves in the direction approaching the upper wire guide member (17b), the inner wire (12b) of the other first wire cable (12+) whose one end is engaged with the engagement portion (15b)
) is loosened, and the wire attachment part (16b) on the front side of the upper end of the arm (4) in the For guide members (
18b), thus increasing the distance between said arm (4)
The mounting plate (9) is maintained horizontally in the X-axis direction even if the upper end is tilted by the tilting of the arm (4), and the arm (4) is rotated by the second cylinder (52) When swinging in the @ direction, the second wire cable +122) (12
The movement of 2) ensures the horizontality of the mounting plate (9) in the Y@ direction in the same way as above, and thus even when the arm (4) is tilted in any direction, the mounting plate (9) remains horizontal. is maintained in a horizontal attitude parallel to the X-Y plane formed by the X@ and Y axes, and the attitude of the processing tool aO attached thereto can be maintained constant.

Also, when the movable arm (4) extends and contracts, a separate frame (2) is used.
Cable locking member 031 provided on and tool mounting plate (9)
Only the slackness of the outer tube (12a) of each cable (12+) (122) between 1Φ changes, and the inner wire (12b) does not pull, and the mounting plate (9) is maintained in a horizontal position. .

(Effects of the Invention) As described above, according to the present invention, the parallel ruler machine that maintains the tool mounting plate in a constant posture is configured using a wire cable, and even when the movable arm expands and contracts, the slack of the cable causes the It can cope with expansion and contraction operations, does not require a separate drive source to expand and contract the links unlike the conventional parallel link type structure, and has the advantage of simplifying the structure of the device and obtaining it at low cost.

[Brief explanation of drawings]

Figure 1 is a front view of a robot equipped with the device of the present invention;
The figure is a low-level side view of the robot taken along line II-II in Figure 3, and Figures 3 to 5 are taken from line ■-■ to v-v in Figure 2.
6 is a side view of a modified example of the lower part, and FIG. 7 is a diagram illustrating its operation. (2) Machine frame (3) (8) Joint (4) Movable arm (9) Tool mounting plate 01) Parallel ruler structure (12+) (122) ...Wire cable (123
)...Outer tube (12b)...Inner wire ('130)...Cable locking member (15a) (15b) (15c) (15d) - Wire 1' wire locking portion (16a) at the lower end of the arm ) (16b H2S
c) (1(ld)--Arm, upper end wire attachment part (17a) (17b) (17cH17d)...
Wire guide member (18a 1 (18b)) on the machine frame side (
18c ) (18d) ・I tool mounting plate side no-wire guide member (1!! 2 people Fig. 7)

Claims (1)

[Claims] 1. A movable arm attached to the machine frame via a joint is extendable in the longitudinal direction, a tool mounting plate is attached to the tip of the arm via the joint, and the mounting plate is attached to the machine frame. A parallel ruler mechanism provided between the arms maintains a constant posture, and in order to configure the mechanism using wire cables, a pair of wire cables corresponding to a predetermined swing direction of the arm is provided. The cables are wired between the machine frame and the mounting plate so that each end of the outer tube of each cable is locked to each cable locking member provided thereon, and both joints are connected to both ends of the arm. Forming wire engaging portions located on one side and the other side in the swinging direction across the axis of the arm to be connected, and connecting each end of the inner wire of one cable of both wire cables to both ends of the arm. The machine frame and the mounting plate are engaged with the respective engagement portions on one side in the swinging direction via wire guide members provided at opposing positions of the respective engagement portions, and the inner wire of the other cable is each end of the arm is connected to the respective engaging portions on the other side of the swinging direction of the arm via wire guide members provided at opposing positions of the respective engaging portions between the machine frame and the mounting plate. A processing tool attitude control device characterized by being locked. 2. The processing tool attitude control device according to claim 1, wherein each of the wire engaging portions is located on a plane passing through the center of rotation of each of the joints.