JPH059950A - Accessory attaching and detaching mechanism for construction machine - Google Patents

Abstract

PURPOSE:To easily attach and detach various accessories within a short time by providing two sets of paired claw bodies on an attaching/detaching body provided on the top end of a boom, and catching a pin provided on an accessory by each set of the claw bodies. CONSTITUTION:In a constructing machine such as an excavator, an attaching/ detaching body 11 is provided on the top end of a boom 5, two sets of paired claw bodies 12-15 turned in reversed directions, respectively, are provided. Of each set of the claw bodies, either of the claw bodies 12, 14 turned downward or the claw bodies 13, 15 turned upward are moved by a hydraulic cylinder 16, so that a pin can be caught by each pair of the claw bodies. A plurality of pins are fixed in parallel to each other on an accessory to be attached and removed, and each pin is caught by the claw bodies 12-15 of the attaching/ detaching body 11, whereby a desired accessory can be connected to the top end of the boom 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine used for excavating and leveling earth and sand, and in particular, an accessory for carrying out various civil engineering construction works is detachably connected to the tip of a boom. The present invention relates to an accessory attaching / detaching mechanism of a construction machine.

[0002]

2. Description of the Related Art In construction machines, especially excavators and machines for digging holes and digging holes called backhoes, accessories attached to a boom are often replaced according to the purpose of work.

Conventionally, excavators have been used extensively in the field of civil engineering and construction work. In this excavator, a bucket for excavating earth and sand was connected to the tip of an arm. And, by swinging the arm and the bucket with a hydraulic cylinder, the arm and the bucket have been widely used for digging earth and sand and forming a groove.

However, the excavator not only carries out the work of digging by attaching a bucket to the tip of the arm, but also uses the mechanism to divert the work to other work. In other words, instead of the bucket attached to the arm, other accessories may be connected and used for specific civil engineering work or construction work. For example, there were cases where buckets with different excavation widths were attached, and work was performed by adjusting the hardness of earth and sand and the width of grooves. In addition, a breaker may be connected to the tip of the arm or a grip may be attached to the arm for breaking work or cargo handling work. By combining these various accessories, the excavator could be applied to a wide variety of construction sites, and the applicability at the work site was improved.

In the case of converting and connecting such accessories, conventionally, the bucket attached to the tip of the arm is removed and the accessories for each application are manually connected.
In this work, first, the pin connecting the arm and the bucket is removed, and the bucket is separated from the arm. Then, after connecting other accessories to the arm, a pin is inserted so as to penetrate the accessory and the arm to connect the two. The work of attaching and detaching accessories for changing the purpose of this excavator has conventionally been done manually, and it takes time to remove and insert pins and replace accessories, and more than one worker is required. It was If the personnel are required to replace the accessory, the efficiency at the work site is hindered. For this reason, if only the operator operating the excavator can freely attach and detach the accessories suitable for the work purpose to the tip of the arm, it will be very efficient in terms of labor and time at the work site. It was rising. Furthermore, if the excavator operator were to be able to perform the replacement work alone, it would not be necessary to have a worker to insert and remove the pin that penetrated the arm, and not only would the work be safe, but the replacement time could be shortened. Met.

Therefore, in order to solve this problem, the same inventor of the present application has proposed an accessory attaching / detaching mechanism in which a hook which can be expanded and contracted up and down is provided at the tip of the arm (for example, Japanese Patent Application No. 2000-242242). No. 25697 of Heisei 2nd year, 196 of Heisei 2nd year
No. 763).

[0007]

In this newly proposed structure, the pin fixed to the accessory such as the bucket can be grasped by the pair of hooks directed in the opposite direction. However, in this proposed mechanism, since the hook is only one pair, the force for grasping the pin is weak. For this reason, it has been desired to develop an accessory attachment / detachment mechanism that can strongly hold the connection between the arm and the accessory.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a movable vehicle body, a boom mounted on the vehicle body and swingable up and down, and a boom provided at the tip of the boom, the length of which can be freely expanded and contracted. In a construction machine comprising a detachable body and an accessory that engages with the detachable body to perform civil engineering work, a downwardly facing claw body is provided at the upper and lower sides of the front side of the detachable body, and at the same time, the upper and lower sides of the front surface of the detachable body. Each of them is provided with a claw body facing upward, and a driving means for simultaneously moving either one of the pair of claw bodies facing downward and the pair of claw bodies facing upward is provided. And fix them in parallel at intervals,
(EN) Provided is an accessory attaching / detaching mechanism of a construction machine capable of engaging accessories from the top and bottom of each pin and connecting accessories to the tip of a boom.

[0009]

In the present invention, the detachable body attached to the tip of the arm is provided with two pairs of hooks facing in opposite directions. The one pair of hooks is set upward, and the other pair of hooks is set downward. And the pin is fixed to the accessory, either one
By moving a pair of hooks in a set to approach a pair of hooks in another set, the hooks in each set act to grab the entire circumference of their respective pins. For this reason, the hook not only contacts and grips the pin but also grips the entire circumference of the pin, so that the holding force of the connection is strong, and the members are deformed even if the accessory is used for civil engineering or construction work. There is no fear.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Here, FIG. 1 is an overall perspective view showing a state in which an accessory is attached to the tip of an arm of an excavator according to an embodiment of the present invention, and FIG. 2 shows a mechanism for attaching and detaching the accessory near the tip of the arm. FIG. 3 is an enlarged view, FIG. 3 is a side sectional view showing a state immediately before attaching the bucket to the tip of the arm, and FIG. 4 is a side sectional view showing a state where the bucket is attached to the tip of the arm.

Crawlers 2 are provided on the lower left and right sides of a vehicle body 1 on which an engine or the like is mounted, and these vehicle bodies 1 can freely move back and forth and left and right. On the front side of the vehicle body 1 is mounted a boom 3 which is bent in a slightly V shape so as to be vertically swingable. Hydraulic cylinders 4 for elevation are respectively mounted between the right and left of the center of the boom 3 and the front surface of the vehicle body 1, and the boom 3 is swung up and down by the hydraulic cylinders 4.

A slightly elongated arm 5 is vertically swingably connected to the upper end of the boom 3, and a swing hydraulic pressure is provided between the rear center of the boom 3 and the rear end of the arm 5. A cylinder 6 is interposed. The hydraulic cylinder 6 allows the arm 5 to swing up and down with respect to the boom 3. Further, the rear end of the bucket cylinder 7 is connected to the center of the rear surface of the arm 5, and the rising links 9 are connected to the left and right of the cylinder rod 8 of the bucket cylinder 7. The lower end is connected to both sides near the tip of the arm 5. A connecting link 10 facing forward is connected to the left and right ends of the cylinder rod 8, and a claw body is detachably attached between the tip of the connecting link 10 and the end of the arm 5 by hydraulic pressure. The body 11 is attached. These arms 5, start-up links 9, connecting links 10, detachable bodies 11
This will form a slightly square link mechanism.

The upper fixing claws 12 facing the lower side are fixed to the upper left and right of the detachable body 11, and the detachable body 11
Lower fixed claws 14 facing downward are fixed to the lower left and right of the. An upward moving claw 13 is provided between the upper fixed claw 12 and the lower fixed claw 14 so as to be movable, and a lower part of the lower fixed claw 14 is directed upward. A lower moving claw body 15 is movably provided. Both the lower fixed claw body 14 and the lower movable claw body 15 can move up and down at the same time, and a hydraulic cylinder for attachment and detachment is provided between the lower fixed claw body 14 and the upper movable claw body 13. 16 are interposed.

The bucket 17 shown in FIG. 1 has a conventionally well-known structure. A mounting body 18 is fixed to the outer periphery of the bucket 17, and the side surface of the mounting body 18 is engaged with a space. Pins 19 and 20 are fixed in parallel.
The engagement pins 19 and 20 are fitted in the attachment pin holes formed in the bucket 17 in the conventional structure,
A configuration in which 20 is inserted and fixed may be used.

Next, the vicinity of the detachable body 11 will be enlarged and described with reference to FIG.

To the left and right of the tip of the cylinder rod 8,
The rising link 9 and the connecting link 10 are rotatably connected by a pin 23. The lower ends of the rising links 9 are rotatably connected to the left and right near the tip of the arm 5 by pins 24. And the detachable body 11
The assembly 25, which is the base of, is formed by bending a steel plate into a U-shape and extending vertically. The inside of the assembly 25, which is bent in a U shape, covers the connecting link 10 and the tip of the arm 5, and the tip of the connecting link 10 and the upper portion of the assembly 25 are rotatably connected by a pin 26. The tip of the arm 5 and the lower part of the assembly 25 are pin 27
It is rotatably connected by.

A rectangular window hole 28 is opened in the upper portion of the flat front surface of the assembly 25.
A pair of upper fixing claws 12 bent in an L shape are fixed to the left and right of the upper part of the plate 8. The hook surface 29 formed on the upper fixed claw body 12 and curved in a C shape is positioned so as to face downward. A pair of lower fixing claws 14 are fixed to the lower part of the front surface of the assembly 25, and the hook surface 33 formed in the lower fixing claws 14 is curved in a C shape.
Is positioned so that it faces downward. And the assembly 2
A slender interlocking body 30 having a length substantially the same as the entire length of the assembly 25 is disposed movably inside the assembly 5, and the window hole 28 is passed through the upper end of the interlocking body 30. The lower part of the upper moving claw 13 is connected. Further, the lower end of the interlocking body 30 is projected below the lower end of the assembly 25, and the lower moving claw 15 is connected to the lower end of the interlocking body 30 at a right angle. These interlocking body 30, upper moving claw body 1
3. The downward moving claws 15 form a U-shaped structure, which can move up and down at the same time.
The hook surface 31 formed on the upper moving claw body 13 and curved in a C shape is the hook surface 2 of the upper fixed claw body 12.
It faces upward so as to face 9. Further, the hook surface 3 formed in the lower moving claw body 15 is curved in a C shape.
2 is directed upward so as to face the hook surface 33 of the lower fixed claw body 14.

A flat plate-shaped support plate 34 is fixed between the pair of lower fixed claws 14 described above, and the base of the hydraulic cylinder 16 for engagement is fixed to the upper surface of the support plate 34. . The hydraulic cylinder 16 has a cylinder rod 35 that can expand and contract, and the tip of the cylinder rod 35 is connected to the upward moving claw 13. With this configuration, the cylinder rod 35 is expanded and contracted by the operation of the hydraulic cylinder 16, and the cylinder rod 35 allows the upper moving claw body 13, the interlocking body 30, and the lower moving claw body 15 to move up and down at the same time.

In the setting of the distance between the upper fixed claw body 12 and the lower fixed claw body 14, the distance between the hook surface 29 and the hook surface 33 is set to the engagement pin 19 fixed to the mounting body 18. The intervals of the engagement pins 20 are matched. Further, the upper moving claw body 13 and the lower moving claw body 1 fixed to the interlocking body 30.
In the setting of the interval of 5, the distance between the inner and inner sides of the hook surface 31 and the hook surface 32 is made equal to the distance between the engagement pins 19 and 20 fixed to the mounting body 18.

Next, the operation of this embodiment will be described with reference to FIGS.
Will be explained together.

First, in FIG. 5, an accessory for the civil engineering work (here, bucket 17) is attached to the tip of the arm 5.
Indicates that the bucket 17 is not attached, and the work for attaching the bucket 17 to the tip of the arm 5 is about to start. In this case, the hydraulic cylinder 1
6, the cylinder rod 35 is contracted. Therefore, the upper moving claw body 13, the interlocking body 30, and the lower moving claw body 15 are lowered downward by the cylinder rod 35, and as shown in FIG. 3, the space between the hook surface 29 and the hook surface 31 and the hook surface 32 and the hook surface 32. The space between the surfaces 33 is widely opened, and the tips of the upper fixed claw body 12 and the upper moving claw body 13 and the tips of the lower fixed claw body 14 and the lower moving claw body 15 are largely separated.

In this state, the hydraulic cylinders 4 and 6 are made to cooperate with each other, and the boom 3 and the arm 5 are swung to move the detachable body 11 toward the bucket 17. FIG. 5 shows a state where the detachable body 11 is approaching the bucket 17, and FIG. 4 shows the engagement pin 1 of the bucket 17.
It is an enlarged view of the state where the upper fixed claw body 12 and the lower fixed claw body 14 were brought into contact with 9, 20. When the detachable body 11 is brought close to the bucket 17, the engagement pin 19 passes between the upper fixed claw body 12 and the upper movable claw body 13 and moves to the elliptical space formed by the hook surface 29 and the hook surface 31. To do. Also, the engagement pin 20
Passes through the space between the lower fixed claw body 14 and the lower moving claw body 15 and moves to the elliptical space formed between the hook surface 32 and the hook surface 33. Thereafter, when the hydraulic cylinders 4 and 6 are operated, the upper surface of the engaging pin 19 can be brought into contact with the inner circumference of the hook surface 29 and the upper surface of the engaging pin 20 can be brought into contact with the inner circumference of the hook surface 33. This contact state is the contact state shown by the solid line in FIG.

In this way, the hook surface 29 is attached to the engaging pin 19.
If the hook surface 33 is brought into contact with the engaging pin 20,
Then, the hydraulic cylinder 16 is operated to extend the cylinder rod 35. Then, the upper moving claw body 13, the interlocking body 30, and the lower moving claw body 15 simultaneously move in the direction indicated by A in FIG.
The hook surface 31 of is closely attached. At the same time, since the lower moving claw body 15 is moved by the interlocking body 30, the hook surface 32 of the lower moving claw body 15 comes into close contact with the lower surface of the engagement pin 20. In this way, the entire circumference of the engaging pin 19 covers the hook surfaces 29, 3 of the upper fixed claw body 12 and the upper moving claw body 13.
This means that the engaging pin 20 is gripped by 1, and the entire circumference of the engaging pin 20 is gripped by the hook surfaces 32, 33 of the lower fixed claw body 14 and the lower moving claw body 15. Thus, each engagement pin 1
If the outer circumferences of 9 and 20 are grasped by the upper fixed claw body 12, the upper movable claw body 13, the lower fixed claw body 14 and the lower movable claw body 15, the bucket 17 is connected to the tip of the arm 5. become. This connected state is the state shown by the chain line in FIG.

As described above, when the bucket 17 is connected to the arm 5, both can be worked together, and when the arm 5 is lifted as shown in FIG. 6, the bucket 17 can also be lifted. Then, the hydraulic cylinders 4, 6, and 7 are made to cooperate with each other, and the boom 3 and the arm 5 are connected.
By swinging up and down, it is possible to perform work with the same function as an ordinary excavator for civil engineering such as excavation and ditching, construction, etc. by the bucket 17.

Contrary to the above, in order to remove the bucket 17 from the tip of the arm 5, the bucket 17 is lowered to the ground in the state shown in FIG.
6 is operated to reduce the cylinder rod 35, and the upper moving claw body 13 and the lower moving claw body 15 are separated from the outer circumferences of the engagement pins 19 and 20. Then, as shown by the solid line in FIG. 4, between the tips of the upper fixed claw body 12, the upper moving claw body 13 and the lower fixed claw body 1.
4. The space between the tips of the lower moving claws 15 is wide open. Next, by controlling the hydraulic cylinders 4 and 6 to swing the arm 5, the engaging pin 19 is moved between the upper fixed claw body 12 and the upper moving claw body 13 and the engaging pin 20 is moved to the lower fixed claw body 14. , The arm 5 and the bucket 17 are separated from each other by pulling them out from between the lower moving claws 15 as shown in FIG. By this procedure, the bucket 17 can be easily removed from the tip of the arm 5.

Next, FIGS. 7, 8 and 9 show another embodiment of the present invention. In this embodiment, the same components as those in the first embodiment shown in FIGS. 1 to 6 are designated by the same reference numerals and the description thereof is omitted.

The assembly 41 interposed between the connecting link 10 and the tip of the arm 5 is formed by bending a steel plate into a U-shaped cross section, and has a flat front surface facing forward and is bent. Connecting link 10 and arm 5 on both sides
Is covered on the tip of. The upper side of the assembly 41 and the tip of the connecting link 10 are rotatably connected by a pin 26, and the lower side of the assembly 41 and the tip of the arm 5 are pin 27.
It is rotatably connected by. And the assembly 4
On the flat front surface of No. 1, a window hole 42 having an elongated shape is opened from the upper part to the central part. This assembly 4
The upper fixed claw body 43 bent in an L shape is fixed to the front and the left of the center of the window hole 42, and the C-shaped hook surface 44 of the upper fixed claw body 43 is downward. Towards. In addition, a pair of lower fixing claws 45 bent in an L shape are provided on the lower left and right sides of the front surface of the assembly 41.
Is fixed, and the hook surface 46 of the lower fixing claw 45, which has a C-shape, faces downward.

Next, an L-shaped angle 47 is fixed to the lower part inside the assembly 41.
A base of a hydraulic cylinder 48 is fixed to the. The hydraulic cylinder 48 is operated by hydraulic pressure, and the driven cylinder rod 49 is directed upward, and an angle 50 is fixed to the upper end of the cylinder rod 49. An interlocking body 51 that moves up and down inside the assembly 41 is fixed to the angle 50, and an upper moving claw body 52 is provided at the upper end of the interlocking body 51 so as to pass through the window hole 42. It is fixed at a right angle, and this upper moving claw body 52
The C-shaped hook surface 53 is directed upward. A lower moving claw 54 is fixed at a right angle to the lower end of the interlocking body 51 so as to pass through the window hole 42, and the C-shaped hook surface 55 of the lower moving claw 54 is directed upward. There is. The positional relationship among the upper fixed claw body 43, the lower fixed claw body 45, the upper moving claw body 52, and the lower moving claw body 54 is as shown in FIG. The lower fixing claw 45 is fixed to the lower part of the assembly 41. The upper moving claw body 52 is located above the upper fixed claw body 43, and the lower moving claw body 54 is located between the upper fixed claw body 43 and the lower fixed claw body 45.

Next, the mounting body 18 in the bucket 17
The engagement pins 57, 58, 59 fixed to the respective positions are arranged in parallel as shown in FIG. 8 and 9, the distance between the engagement pins 57, 58, 59 and the positional relationship among the upper fixed claw body 43, the lower fixed claw body 45, the upper moving claw body 52, and the lower moving claw body 54 are shown. . That is, the engagement pin 5
The distance between 8 and 59 is set to match the distance between the hook surfaces 44 and 46 of the upper fixed claw 43 and the lower fixed claw 45. The distance between the engaging pins 57 and 58 is set to match the distance between the hook surfaces 53 and 55 of the upper moving claw body 52 and the lower moving claw body 54. Then, when the hydraulic cylinder 48 is operated to reduce the cylinder rod 49, the upper moving claw body 52 and the lower moving claw body 54 simultaneously move downward,
As shown in FIG. 8, the distance between the tips of the upper fixed claw 43 and the lower moving claw 54 is wide. At this time, the tip of the upper moving claw body 52 and the tip of the lower fixing claw body 45 are smaller than the gap between the inner circumferences of the engaging pin 57 and the engaging pin 59, and the upper fixing claw body 4
3 and the tip of the lower moving claw 54 is wider than the outer diameter of the engaging pin 58. Therefore, when the entire assembly 41 is moved to the left at the position of FIG. 8, the upper moving claw body 52 and the upper fixed claw body 43 are inserted into the gap between the engagement pins 57 and 58,
The lower moving claw 54 and the lower fixed claw 45 are engaged with the engaging pins 58 and 59.
Is inserted in the gap. Further, the engagement pin 58 is inserted into the elliptical space formed by the upper fixed claw body 43 and the lower fixed claw body 45.

Next, an operation for connecting the bucket 17 to the tip of the arm 5 in the second embodiment will be described.

As described above, as shown in FIG. 8, the hydraulic cylinder 48 is operated to reduce the cylinder rod 49, and a space is provided between the tips of the upper fixed claw body 43 and the lower movable claw body 54. The engaging pin 58 is inserted and the engaging pin 5 is inserted.
8 is inserted in the elliptical space formed by the hook surfaces 44, 55. At the same time, the upper moving claw member 52 is placed between the engaging pins 57 and 58, and the lower fixed claw member 45 is placed between the engaging pins 58 and 5.
Insert between 9. Then, by swinging the arm 5, the assembly 41 is lowered slightly in FIG. 8, and the hook surface 44 is engaged with the engaging pin 58 and the hook surface 46 is engaged with the engaging pin 59.
Stick it to the upper half of the. This state is the state shown by the solid line in FIG. 9, and is the state in which the engagement pins 58 and 59 are engaged with the upper fixed claw body 43 and the lower fixed claw body 45. Then, in this state, hydraulic pressure is supplied to the hydraulic cylinder 48 to extend the cylinder rod 49, and the angle 50 and the interlocking body 51 are moved in the B direction in FIG. Then, the upper moving claw body 52 and the lower moving claw body 54 connected to the interlocking body 51 move upward, and the hook surface 53 of the upper moving claw body 52 is engaged with the engagement pin 57.
The lower half surface of the lower moving claw 54 is in close contact with the lower half surface of the engaging pin 58. Therefore, when the cylinder rod 49 moves in the B direction, the entire circumference of the engagement pin 58 is grasped from above and below by the hook surfaces 44 and 55, and the lower half of the engagement pin 57 and the upper half of the engagement pin 59 are grasped. Means that the hook surfaces 53 and 46 are sandwiched by half the circumference. By operating the hydraulic cylinder 48 in this manner, the engaging pins 57, 58, 59 are firmly gripped by the upper fixed claw body 43, the lower fixed claw body 45, the upper moving claw body 52, and the lower moving claw body 54. Thus, the bucket 17 is firmly connected to the tip of the arm 5.

[0032]

Since the present invention is configured as described above, the accessory attaching / detaching mechanism of the present invention is provided at the tip of a conventional excavator, and the accessory attaching / detaching mechanism of the present invention is parallel to the accessory used for civil engineering work and construction work such as buckets. It has a simple structure with fixed engagement pins, but various accessories can be attached to or detached from the end of the arm in a short time.

The selection and attachment / detachment operation of the accessory can be performed by remote control of one operator who is on the vehicle body of the excavator. No workers required,
Labor saving can be achieved. Further, the plurality of engaging claws of the accessory attaching / detaching device are firmly meshed with the engaging pin attached to the bucket or the like, and the connection between the two is strengthened.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing a configuration of an excavator to which an embodiment of the present invention is applied.

FIG. 2 is an enlarged perspective view showing a main part of an accessory attaching / detaching mechanism attached to a tip of an arm.

FIG. 3 is a side sectional view showing a structure of an accessory attaching / detaching mechanism and a bucket.

FIG. 4 is a cross-sectional view showing a state in which the accessory attaching / detaching mechanism is engaged with the bucket.

FIG. 5 is an explanatory diagram showing a state immediately before attaching the bucket to the tip of the arm.

FIG. 6 is an explanatory view showing a state where a bucket attached to the tip of the arm is lifted.

FIG. 7 is an enlarged perspective view showing a main part of a second embodiment of the accessory attaching / detaching mechanism attached to the tip of the arm.

FIG. 8 is a side sectional view showing a structure of an accessory attaching / detaching mechanism and a bucket in the second embodiment.

FIG. 9 is a cross-sectional view showing a state in which the accessory attaching / detaching mechanism is engaged with the bucket in the second embodiment.

[Explanation of symbols]

1 car body 3 boom 5 arms 11 Detachable body 12 Upper fixed claw body 13 Upper moving claw body 14 Lower fixed claw body 15 Lower moving claw body 17 buckets 19 Engagement pin 20 engagement pin 29 Hook surface 30 interlocking body 31 Hook surface 32 hook surface 33 Hook surface

Claims (2)

[Claims] 1. A movable vehicle body, a boom mounted on the vehicle body and capable of swinging up and down, a detachable body provided at the tip of the boom and capable of freely extending and contracting its length, and a detachable body thereof. In a construction machine consisting of an accessory engaged for civil engineering work, claw bodies facing downward are provided above and below the front surface of the detachable body, and at the same time, claw bodies facing upward and downward above the front surface of the detachable body. Is provided with a driving means for simultaneously moving either one of the pair of downwardly facing claws and the pair of upwardly facing claws, and a pair of pins are fixed in parallel to the accessory at a distance. However, an accessory attachment / detachment mechanism for construction machinery that allows the hooks to engage with each other from the top and bottom of each pin to connect the accessory to the tip of the boom. 2. A movable vehicle body, a boom mounted on the vehicle body and capable of swinging up and down, a detachable body provided at the tip of the boom and capable of freely extending and contracting its length, and a detachable body thereof. In a construction machine consisting of an accessory engaged for civil engineering work, a pair of pawls facing in one direction are provided at the top and center of the front surface of the detachable body, and at the center and bottom of the front surface of the detachable body. A pair of claw bodies facing the other direction are provided, and a drive means for simultaneously moving one of the combination claw bodies is provided, and three pins are fixed to the accessory in parallel with each other at intervals. After inserting the claw body between the pins, the pair of claw bodies in any one combination are simultaneously moved by the driving means, the center pin is held from both sides by the pair of center claw bodies, and the upper and lower claw bodies are also held. Press the pins on both sides and attach the accessory to the tip of the boom. An attachment / detachment mechanism for construction machinery that can be detachably connected.