JP2022161275A - Device for work in surroundings with height limit using arm and boom - Google Patents

Abstract

To provide a device allowing work to be efficiently carried out in surroundings with height limit.SOLUTION: A hydraulic shovel 10 comprises: a machine body 11; a boom 20 vertically swingable with respect to the machine body; an arm 30 vertically swingable with respect to the boom; a bucket 40 attached on a tip of the arm; a boom cylinder 21 making the boom swing vertically; an arm cylinder 31 making the arm swing vertically; an operation cylinder 41 making the bucket swing vertically; a first limit mechanism 61 limiting a swing range of the boom by the boom cylinder within height limit; and a second limit mechanism 62 swingably limiting a swing range of the arm by the arm cylinder to a limit angle less than 180 degrees in the upper vertical angle to the boom.SELECTED DRAWING: Figure 1

Description

The present invention relates to a device such as a hydraulic excavator that uses an arm and boom to work in environments with height restrictions.

Patent Document 1 discloses that as a means for limiting the working height of a work attachment as a safety device for a hydraulic excavator, the rotation angle of a boom, an arm, etc. is detected by detecting a swing angle, and the detection signal is input to a controller. Such devices are very expensive and could not be installed on small hydraulic excavators in terms of cost efficiency. A limit switch is detachably attached to the outer periphery of the cylinder tube, and the limit switch is connected in series to the solenoid of the electromagnetic on-off valve interposed in the pilot circuit on the discharge side of the pilot pump to form an electric circuit. It is described that an abutting member capable of abutting against the contactor of the limit switch is detachably attached to the rod of the cylinder.

Patent Document 2 describes a front structure as a working height limiter for construction machinery that can reliably prevent accidental contact between a front member and an obstacle above it without reducing the operating speed of an actuator that drives the front member as much as possible. In addition to setting monitor points on the boom, arm, and bucket, respectively, set a deceleration area with a different size (distance) for each monitor point below the no-entry area, and when operating the front, each monitor point It is determined whether or not the corresponding deceleration area has been reached, and if any one of the monitor points has reached the corresponding deceleration area, the degree of deceleration is obtained according to the height of that monitor point, and this value is used as the current value. is described as decelerating the actuator by multiplying the operating speed of the actuator.

Japanese Utility Model Laid-Open No. 5-42354 JP-A-7-150594

For equipment such as hydraulic excavators (backhoes) that work in environments with height restrictions such as under overhead wires, the range in which the boom can be swiveled up and down so that the arm and boom are within the height restrictions. is set. For this reason, for example, when a dump truck designed to run on a track such as a railroad track and on a road moves on the track, a working tool such as a bucket attached to the tip of the arm of the backhoe and the loading platform of the dump truck are in contact with each other. There is a case where interference or sufficient clearance cannot be secured.

One aspect of the present invention is an apparatus for working with an arm and boom in environments with height restrictions. This device (work device) consists of a machine body, a boom that can swing up and down with respect to the machine body, an arm that can swing up and down with respect to the boom, a work tool attached to the tip of the arm, and a boom that can be moved up and down. A boom cylinder for swinging, an arm cylinder for swinging the arm up and down, an operation cylinder for swinging the work tool up and down, and a first limit for limiting the swinging range of the boom by the boom cylinder within the height limit. and a second limiting mechanism that limits the swinging range of the arm by the arm cylinder to a limit angle of less than 180 degrees above the boom.

The movable range of a working tool such as a bucket attached to the tip of the arm can be secured by moving the boom up and down. Therefore, conventionally, the movable range of the arm is set to be horizontal with the boom or below. In an environment with a height limit, accessories such as arm cylinders attached to the boom, or the rear end of the arm (blanket), which is the joint with the boom, rises together with the boom, and the height of the first limit mechanism increases. Subject to restrictions. By providing a second limit mechanism that limits the swing range of the arm by the arm cylinder to a limit angle of less than 180 degrees above the boom, accessories such as the arm cylinder, or the rear end of the arm, etc. It is possible to bring the tip of the arm closer to the height limit while keeping the portion related to the boom within the height limit. Therefore, in an environment with height restrictions, it is possible to widen the swinging range of the work implement attached to the tip of the arm.

This working device may have a third limiting mechanism for limiting the swinging range of the working tool by the operation cylinder so as to keep the swinging range of the working tool within the height limit.

A typical example of a working device is a hydraulic excavator, which has wheels for track traveling provided in front and rear of the machine body and a ground carrier provided in the lower part of the machine body so as to perform work under overhead wires. It may be a track and land working device.

The limiting angle θ1 by the second limiting mechanism may satisfy the following condition (1).
160<θ1<180 (1)
The lower limit of condition (1) may be 170 degrees, and the upper limit may be 175 degrees.

Moreover, the work device may further include an offset cylinder capable of swinging the arm in the left-right direction.

The figure which shows the outline|summary of the hydraulic excavator of an example of this invention. The figure which shows the outline|summary of the conventional hydraulic excavator. The figure which extracts and shows an arm. The figure which extracts and shows an operation cylinder.

FIG. 1 shows an outline of a hydraulic excavator (backhoe) 10 as a working device according to one embodiment of the present invention. The hydraulic excavator 10 includes an engine and a control device, and includes a body 11 on which an operator rides and controls the hydraulic excavator 10 , a boom 20 that can swing up and down with respect to the body 11 , and a boom that swings up and down with respect to the boom 20 . a possible arm 30, a work tool attached to the tip of the arm 30, in this example a bucket 40, a boom cylinder 21 for vertically swinging the boom 20, an arm cylinder 31 for vertically swinging the arm 30, and an operation cylinder 41 for swinging the bucket 40 up and down.

More specifically, a rotating boom (blanket) 25 that can move and rotate in the left-right direction is connected to the tip of a boom 20 that can be raised and lowered with respect to the machine body (vehicle body) 11 . An offset cylinder 26 that moves (offsets) the rotating boom 25 in the horizontal direction and a horizontal excavation cylinder 27 that rotates the rotating boom 25 in the horizontal direction without offsetting are attached.

The arm 30 is vertically rotatably connected to the rotating boom 25 via a pin through a connecting hole 33 provided at the base end 38 of the arm 30 , and is connected to a driving hole 34 provided at the upper rear side of the connecting hole 33 . It is adapted to be driven up and down by the arm cylinder 31 which is mounted. The arm cylinder 31 is attached to the upper portion of the rotating boom 25 by a trunnion mount so as to be able to swing, and the tip 31a is connected to the drive hole 34 of the base end 38 of the arm 30. As shown in FIG. Therefore, the rear end 31 b of the arm cylinder 31 is supported so as to project upward from the rotating boom 25 .

A base end 38 of the arm 30 is further provided with a support hole 35 for an operation cylinder 41 for vertically rotating the bucket 40 in front of the drive hole 34 . A bucket 40 is attached to the tip 37 of the arm 30 via a link mechanism 42 so as to be vertically rotatable by an operation cylinder 41 . An overhead wire guard 29 is provided on the upper portion of the rotating boom 25 to prevent contact with the overhead wire.

This hydraulic excavator 10 has wheels 12 for track traveling provided on the front and rear of the machine body 11 and a ground traveling body (crawler) 13 provided on the lower part of the machine body 11 . Therefore, the hydraulic excavator 10 is a track and land hydraulic excavator that can move on the track 2 with the wheels 12 and move on the ground surface 3 or the road with the traveling body 13 . Furthermore, work can be performed in an environment with a height limit such as under the overhead wire 9, and an example of the height limit H is 4 m. In order to safely work in a work environment with a height limit, the hydraulic excavator 10 has a first height limit H that limits the swinging range (vertical turning range) of the boom 20 by the boom cylinder 21. It has a limiting mechanism 61 . The first limit mechanism 61 allows the boom cylinder 21 to extend to a height where the overhead wire guard 29 attached to the tip of the boom 20 reaches the limit height H.

One example of the first limiting mechanism 61 is to limit the extent of extension of the boom cylinder 21; for example, a collar can be inserted to limit the range of motion of the piston within the boom cylinder 21. The first limit mechanism 61 may be a limit switch that detects the extension amount (extension amount) of the boom cylinder 21, or may be another suitable control circuit or control method.

The hydraulic excavator 10 further includes a second limit mechanism that limits the swing range (vertical rotation range) of the arm 30 by the arm cylinder 31 to a limit angle in which the upper angle θ with respect to the boom 20 is less than 180 degrees. 62. In this example, the excavator 10 has an angle ? It has a second limit mechanism 62 capable of rotating the arm 30 up to a limit angle θ1 of less than 180 degrees. The reference line of the boom 20 may be a reference line indicating a structurally representative portion such as the centerline of the front portion of the boom 20 including the connection hole 33 with the arm 30 . The reference line of arm 30 may be a reference line representing a structural representative portion of arm 30 , such as a line including connection hole 33 with boom 20 and connection hole with bucket 40 .

The second limiting mechanism 62 of this example is a combination of the arm cylinder 31 and the distance between the connecting hole 33 and the drive hole 34 at the proximal end 38 of the arm 30, and the arm cylinder 31 expands and contracts to the shortest distance. The position of the drive hole 34 is set so that the arm 30 can be pulled up to the limit angle θ1 with respect to the boom 20 at times. The second limit mechanism 62 may limit the extension range of the arm cylinder 31, may be a limit switch for detecting the extension amount (extension amount) of the arm cylinder 31, or may be any other suitable control mechanism. It may be a circuit or a control method.

FIG. 2 shows an example of a conventional hydraulic excavator 90. As shown in FIG. The hydraulic excavator 90 has a basic configuration in common with the hydraulic excavator 10 described above, and the rotation range of the arm 30 with respect to the boom 20 is set to 180 degrees. That is, it is equivalent to setting the rotatable range (limit angle) θ1 of the arm 30 with respect to the boom 20 to 180 degrees. One of the design points at which the moment of the arm cylinder 31 becomes the largest is when the angle of the arm 30 with respect to the boom 20 is 180 degrees, and the amount of expansion and contraction of the arm cylinder 31 is determined at that point. Beyond the movable range of arm cylinder 31 , the height of bucket 40 is primarily controlled by the angle of boom 20 .

In a work environment with a height limit, the swing angle of the boom 20 is limited by the first limit mechanism 61 for safety in the conventional hydraulic excavator 90 . However, it is the accessory attached to the boom 20, in this example the overhead wire guard 29 or the rear end 31b of the arm cylinder 31, that reaches the height limit H, and the arm 30 rises above the height limit H. Sometimes there is room to turn. Depending on the model, the portion where the height limit H is reached first may be the upper end of the proximal end 38 of the arm 30, but even then, the arm 30 often has room to pivot upwards. .

Under overhead lines, hydraulic excavators 10 and 90 may work together with a track-and-land carrier, such as a truck 50 having wheels 52 running on tracks 2 and tires 53 running on roads 3. be. At this time, even if the boom 20 is raised to the limit height, sufficient clearance cannot be secured between the position of the tip 49 when the bucket 40 is rotated up and down and the bed 55 of the truck 50 on the track 2. , work efficiency may be greatly reduced.

As shown in FIG. 1 again, by setting the limit angle θ1 of the angle (upper angle) θ between the arm 30 and the boom 20 to less than 180 degrees by the second limit mechanism 62, the arm cylinder 31 , the arm 30 can be rotated (rotated) so as to warp with respect to the boom 20 . Therefore, the position of the tip 37 of the arm 30, which is the center of the swing of the bucket 40, can be brought closer to the limit height H, and the position of the tip 49 when the bucket 40 is rotated up and down and the position of the tip 49 on the track 2 can be adjusted. A sufficient clearance D can be ensured between the truck 50 and the loading platform 55 of the truck 50 . For example, in a small hydraulic excavator with a working radius of about 6.5 m and a bucket capacity of 0.25 m ³ , in an environment where the height limit H is 4 m, the passing position of the tip 49 of the bucket 40 is about several 100 mm (for example, about 300 mm). can be raised.

The limit angle θ1 of the angle θ between the arm 30 and the boom 20 may be reduced until the tip 37 of the arm 30 reaches the height limit H. On the other hand, when the tip 37 of the arm 30 approaches the height limit H, the turning radius of the bucket 40, which is a working tool (attachment), is limited, which may interfere with work such as grooving. Therefore, as described above, the limiting angle θ1 by the second limiting mechanism 62 may satisfy the following condition (1).
160<θ1<180 (1)
The lower limit of condition (1) may be 165 degrees or 170 degrees, and the upper limit may be 175 degrees.

The arm 30 is extracted and shown in FIG. The base end 38 of the arm 30 has a connecting hole 33 connected to the boom 20, a drive hole 34 connected to the tip 31a of the arm cylinder 31, and a support connected to the operation cylinder 41, which are arranged in order from the bottom. and holes 35 . Also, a connecting hole 39 with the bucket 40 is included at the tip 37 of the arm 30 . By adjusting the distance G between the connecting hole 33 of the proximal end 38 of the arm 30 and the drive hole 34 to increase the rotation angle of the arm 30 due to the expansion and contraction of the arm cylinder 31, the second limiting mechanism 62 limits the angle θ1. may be set so as to satisfy the condition (1). For example, the shortening amount ΔG of the distance G of the arm 30 of the hydraulic excavator 10 of this example with respect to the distance G of the arm 30 of the conventional hydraulic excavator 90 may be set so as to satisfy the following condition (2).
0.025<ΔG/G<0.05 (2)
Also, the effective length of the arm 30 (for example, the distance between the connecting hole 33 with the boom 20 and the connecting hole (front end side) 39 with the bucket 40) W, the shortening amount ΔG satisfies the following condition (3). can be set as
0.006<ΔG/W<0.015 (3)

As an example, when the effective length W of the arm 30 is about 1500 to 1550 mm, the distance G between the conventional connecting hole 33 and the drive hole 34 is about 410 to 420 mm. By setting ΔG to about 10 to 20 mm, the limit angle θ1 by the second limit mechanism 62 can be set to an appropriate value less than 180 degrees.

By shortening the distance G between the connecting hole 33 of the arm 30 and the boom 20 and the drive hole 34 , the drive hole 34 is shifted toward the tip 37 of the arm 30 . Therefore, the distance F between the drive hole 34 and the support hole 35 of the hydraulic excavator 10 of this embodiment may be shorter than that of the conventional hydraulic excavator 90 . Also, the distance E between the drive hole 34 and the connecting hole 39 at the tip may be shortened.

The hydraulic excavator 10 includes a third limiting mechanism 63 that limits the swinging range (the range of vertical rotation) of the bucket (work implement) 40 by the operation cylinder 41 . FIG. 4 shows an example of the third limiting mechanism 63. As shown in FIG. As shown in FIG. 4(a), a collar 65 is inserted as shown in FIG. 4(b) into the piston of the operation cylinder 41 which expands and contracts to a length L1 when contracted and a length L2 when expanded. By doing so, the length L3 when shrunk can be made longer than the length L1. As a result, the angle at which the bucket 40 is turned upward by the operation cylinder 41 can be limited. On the other hand, since the length L2 when extended can be set to be the same, the lower turning angle of the bucket 40 can be maintained. The third limit mechanism 63 may be a limit switch that detects the extension amount (extension amount) of the operation cylinder 41, or may be another suitable control circuit or control method.

As described above, in the hydraulic excavator 10 of this example, the second limiting mechanism 62 is provided to set the limiting angle θ1 of the angle (upper angle) θ between the arm 30 and the boom 20 to less than 180 degrees. As a result, the swivel range of the arm 30 can be extended upward while the height limit of the boom 20 is maintained, and the movable range of the bucket 40 can be extended upward. Therefore, in a working environment with a height restriction, the working efficiency in an environment with a height restriction can be improved, such as by widening the movable range of the bucket 40 upward and securing clearance for the truck 50 with respect to the bed 55 .

In the above, a ditching bucket is shown as an example of a working tool (attachment) attached to the tip of the arm 30, but various types of buckets such as a trapezoidal bucket and a skeleton bucket may be used. Furthermore, it is not limited to a bucket, and may be a crusher or the like. Moreover, the combination of the boom 20 and the arm 30 of the work device is not limited to one pair, and may include two or more pairs. The working device is typically a hydraulic excavator, and may be a working device called a backhoe, a digger, an excavator, or the like.

10 hydraulic excavator, 20 boom, 30 arm, 40 bucket

Claims (6)

Airframe and
a boom that can swing up and down with respect to the airframe;
an arm that can swing up and down with respect to the boom;
a working tool attached to the tip of the arm;
a boom cylinder for vertically swinging the boom;
an arm cylinder for vertically swinging the arm;
an operation cylinder for vertically swinging the work implement;
a first limit mechanism for limiting a swinging range of the boom by the boom cylinder within a height limit;
and a second limiting mechanism for limiting the swinging range of the arm by the arm cylinder to a limit angle of less than 180 degrees above the boom. In claim 1,
A working device comprising a third limiting mechanism for limiting a swinging range of the working tool by the operating cylinder. In claim 1 or 2,
A work device, wherein the work device is a hydraulic excavator. In any one of claims 1 to 3,
Wheels for track running provided in front and rear of the airframe;
A work device having a ground traveling body provided at a lower portion of the machine body. In any one of claims 1 to 4,
The working device, wherein the limit angle θ1 satisfies the following conditions.
160<θ1<180 In any one of claims 1 to 5,
A working device further comprising an offset cylinder capable of swinging the arm in the left-right direction.

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