JPH0192088A - Detector for quantity of flexible arm bent - 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 device for detecting the amount of bending of a flexible arm that can be bent in any direction and is used in an industrial robot or the like.

[Conventional technology]

A flexible arm as shown in Japanese Patent Publication No. 59-21758 is known.

That is, as shown in FIG. 9, a large number of articulating members 2 having upper and lower contact surfaces 1 curved in a convex shape are sequentially arranged so that the contact surfaces are in contact with each other, and the most advanced articulating member 2 is 2' connected to four flexible cords, e.g. wire 3
is connected to the four cylinders 5 installed in the base 4 through each joint member 2, and by expanding and contracting the two cylinders 5 forming a pair in the -4 cylinders 5. It is a flexible arm that can swing each articulating member 2 in any direction and bend in any direction.

These four cylinders 5 are connected and controlled to a pump 7 and a tank 8 via servo valves 6, as shown in FIG.

That is, the reduction amount 5a is connected to the first outlet 61 of the servo valve 6 via the pilot-operated check valve 9, and the extension chamber 5b is connected to the first outlet 61 of the servo valve 6.
is directly connected to the tank 8, and constantly supplies pressurized oil to the reduction chamber 5a of the cylinder 5 to stretch the wire 3 so that each joint member 2 is in an upright position, and by switching and operating the servo valve 6. By creating a difference in pressure in the contraction chambers 5a of the pair of cylinders 5, one wire 3 is pulled, the other wire 3 is loosened, and each joint member 2 is oscillated to bend the flexible arm. That's how it is.

[Problem that the invention seeks to solve]

In such a flexible arm, since the amount of swing of each articulating member becomes the amount of bending of the flexible arm, that is, the amount of change in posture, it is necessary to detect the amount of bending of the flexible arm from the amount of swing of each articulating member.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a flexible arm bending amount detection device that can detect the bending amount of a flexible arm.

[Means and actions for solving the problem] The proximal end of a flexible cable is connected to the piston rod 24 of each cylinder 5, and a stroke sensor A for detecting the stroke of the piston rod 24 is attached. 24
The amount of bending of the flexible arm can be detected based on the stroke of the flexible arm.

, [Example] The present invention will be described in detail below with reference to FIGS. 1 to 8. Note that members that are the same as those in the prior art have the same reference numerals.

As shown in FIGS. 3 and 4, the base 4 has a lower plate 10, an intermediate plate 11, and an upper plate 12 connected at intervals by four connecting rods 13, and a cover unit 14 is attached around them. It is. In addition,
The connecting rod 13 is divided into two parts, the lower connecting rod 13a is screwed into the screw hole 16 of the lower plate 10, the upper protrusion 17 is fitted into the hole 181 of the intermediate plate 12, and the upper connecting rod 13a is screwed into the screw hole 16 of the lower plate 10. 1
The lower threaded part 19 of the lower connecting rod 13m is screwed into the threaded hole 20 drilled in the upper part of the lower connecting rod 13m, and the upper threaded part 21 is screwed into the upper plate 12.
It passes through the hole 22 of the hole 22, and a nut 23 is screwed into the hole 22.

The four cylinders 5 are installed between the lower plate 10 and the intermediate plate 11, and their piston rods 24 are inserted into the holes 2 of the intermediate plate 11.
The wire 3 is connected to the piston rod 24, and the wire 3 projects upward from the upper plate 12. The servo valve 6 is attached to the intermediate plate 11, and the wire 3 is connected to the piston rod 24. It communicates with the contraction chamber 5a through the intermediate plate 11, and the extension chamber 5b communicates with an oil hole 26 bored in the lower plate 10.

This eliminates the need to provide piping to each cylinder 5, which simplifies piping work and is advantageous in terms of space.

As shown in FIG. 1, a stroke sensor A is provided to detect the stroke of the piston rod 24 of the cylinder 5.

That is, the hole 32 formed at one end of the connecting plate 31 fits into the tip threaded portion 24a of the piston rod 24, and is pressed against the upward stepped portion 24b by the spring 34 provided between it and the nut 33. Hole 3 formed in the middle of the connecting plate 31
A guide rod 36 is inserted into the hole 37 formed at the other end through the linear ball guide 30, and a stroke sensor A is inserted into the hole 37 formed at the other end.
1. For example, a flexible rod 39 of a direct-acting position detector 38 is connected, and the guide rod 36 extends between a lower bracket 40 fixed to the cylinder 5 and an upper bracket 41 attached to the upper plate 12 of the base 4. They are connected and parallel to the flexible rod 39.

Note that the four cylinders 5 are similarly provided with stroke sensors A.

Therefore, the stroke of the piston rod 24 is
1 to the movable rod 39, the stroke can be detected by the direct-acting position detector 38, and the amount of bending of the flexible arm can be detected based on the stroke.

Furthermore, since the connecting plate 31 is pressed against the upward step portion 24b of the piston rod 24 by the spring 34, there is no play between the piston rod 24 and the connecting plate 31 in the direction of expansion and contraction, and the stroke of the piston rod 24 can be accurately detected. can. In other words, if there is play in the direction of expansion and contraction, the stroke of the piston rod 24 and the stroke of the movable rod 39 will be different, making it impossible to accurately detect the stroke.

Further, since the guide rod 36 is slidably fitted into the hole 3o formed in the middle of the connecting plate 31 via the linear ball guide 3o, even if the connecting plate 31 receives rotational force from the piston rod 24, Since the reaction force of the rotational force is received by the guide rod 36 and not transmitted to the movable rod 39, the direct-acting position detector 38 will not be damaged. In other words, guide rod 3
6, the connecting plate 31 is moved by the rotational force of the piston rod 31.
rotates, and an unreasonable force is applied to the direct-acting position detector 3B, resulting in damage.

Note that the fitting part between the piston rod 24 and the connecting plate 31 does not need to be on the entire circumference, and it is sufficient if it is around 173 of the circumference, and the gap in the radial direction is due to the movement of the connecting plate 31, but it is not necessary to extend the fitting part around the entire circumference. It is determined by the allowable displacement position of the dynamic position detector 38.

In addition, although precision is required for positioning during installation and the assembly work is complicated, the sliding portion between the guide rod 36 and the connecting plate 31 can be fixed by itself, and the sliding portion between the connecting plate 31 and the guide rod 36 can be It may also have a structure that prevents rotation.

FIG. 5 shows a second embodiment, in which a movable rod 39 is loosely fitted into a hole 37 of a connecting plate 31, a lower presser plate 43 is attached with a lock nut 42, and a spring is inserted between a lower presser plate 44 and a nut 45. 46 is provided and the upper and lower presser plates 44 and 43 are connected to the connecting plate 3.
1 and the movable rod 38 are connected. In FIG. 5, a sleeve 48 attached to the wire 3 is screwed into the blind hole 47 of the piston rod 24, and a spring 34 is provided between the lock nut 49 screwed onto the sleeve 48 and the connecting plate 31. .

In this way, the movable rod 39 can be displaced horizontally with respect to the connecting plate 31, so the parallelism between the guide rod 36 and the direct-acting position detector 38 will deteriorate due to installation error, and the piston rod 24 and the connecting plate As the movable rod 31 moves up and down, the movable rod 39 does not oscillate in the horizontal direction even if it is displaced in the horizontal direction, so damage caused by this can be prevented.

In addition, since the upper and lower presser plates 44.43 slide along the connecting plate 31, they may be made of a low-friction material, or they may be made of a low-friction material between the upper and lower presser plates 44.43 and the connecting plate 31. Preferably, a plate is used.

Alternatively, the upper part of the movable rod 39 may be formed into a stepped shape, and the peripheral edge of the hole 37 of the connecting plate 31 may be pressed against the stepped portion by a spring.

6 to 8 show a third embodiment, in which a bracket 50 is attached to the cylinder 5, a guide rod 36 is slidably supported on the bracket 50 via a linear ball guide 30, and the guide rod 36 is slidably supported on the bracket 50 via a linear ball guide 30. 36 to the connecting plate 31, and
A receiving piece 51 made of a low-friction material attached to the connecting plate 31 is brought into contact with the lower surface of the flange 52 of the piston rod 24, and the bolt 5 is
The connecting plate 31 and the piston rod 2 are pressed against the upper surface of the flange 52 by pressing the holding piece 55 which is rocked downwardly by the spring 54 and the connecting plate 31.
4 is connected.

〔Effect of the invention〕

Since the amount of rocking of the articulating member 2 can be determined by detecting the stroke of the piston rod 24 of the cylinder 5, the amount of bending of the flexible arm can be detected.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a front view of the main part, FIG. 2 is a plan view thereof, FIG. 3 is a front view of the base part, and FIG. 4 is a front view of the main part. 5 is a front view of the second embodiment, FIG. 6 is a front view of the third embodiment, FIG. 7 is a side view, FIG. 8 is a plan view, and FIG. 9 is a view of the flexible arm. The schematic perspective view, FIG. 10, is a hydraulic circuit diagram of the cylinder. 1 is a contact surface, 2 is a joint member, 4 is a base, 5 is a cylinder, 6 is a servo valve, 24 is a piston rod, and A is a stroke sensor. Applicant Komatsu Manufacturing Co., Ltd. Representative Patent Attorney Masaaki Yonehara

Claims (1)

[Claims] A large number of articulation members 2 having convex contact surfaces 1 on top and bottom,
These joint members 2 are arranged in sequence so that their contact surfaces are in contact with each other, and the four flexible cables are arranged so that they can be swung in any direction, and each flexible cable is connected to the cylinder 5. In each connected flexible arm, the proximal end of the flexible cable is connected to the piston rod 24 of each cylinder 5, and a stroke sensor A for detecting the stroke of the piston rod 24 is attached. A device for detecting the amount of bending of a flexible arm.