JP2002128497A - Work platform load detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work platform load detecting device having a comparatively simple composition and capable of directly detecting a work platform load. SOLUTION: This work platform load detecting device has a post member 8 attached to a tip of a boom 4, a parallel linkage 9 vertically and swingably attached to the post member 8, and a work platform 10 attached to a tip of the parallel linkage 9. It is also provided with a support spring 11 arranged between the work platform and the post member to suppress vertical swinging movement of the work platform to the post member by the parallel linkage, and a limit switch 12 detecting the work platform load on the basis of a compressive deformation of the support spring 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work table attached to the tip of a boom that can be raised and lowered freely, such as an aerial work vehicle, and more particularly to a device for detecting the work table load.

[0002]

2. Description of the Related Art An aerial work vehicle, for example, has a swivel provided on a vehicle body such as a truck, a boom is mounted on the swivel so as to be able to move up and down, and a vertical post is provided at the tip of the boom. A work table is attached to a vertical post so that it can be swiveled horizontally (swing freely). In such an aerial work vehicle, the position of the worktable with respect to the vehicle body changes according to the ups and downs of the boom, and the overturning moment acting on the vehicle body from the worktable or the like changes. For this reason, it has been well known in the related art to use a fall prevention device such as a moment regulating device or a work range regulating device in order to prevent the stability of the vehicle body from being impaired due to an excessive moment in the overturn direction.

In such an overturn prevention device, it is necessary to accurately detect the overturning moment acting on the vehicle body from the workbench and the boom side, and the moment is detected from the axial force of the boom cylinder, the leveling cylinder and the like. Alternatively, the moment is calculated from the load of the worktable and the position of the worktable. Here, when the moment is detected from the axial force of the boom cylinder, the leveling cylinder, or the like, when the work platform load changes, the moment is calculated based on the axial force that changes according to the load change. There is an advantage that the fall can be prevented without detecting the platform load (that is, without providing the work platform load detecting device).

[0004]

However, in general, in an aerial work vehicle, the allowable load on the workbench is predetermined, and even when the vehicle is overloaded exceeding the allowable load, regulation is required. In many cases, an alarm operation or the like is required, and there is a problem that such an overload cannot be detected when the moment is directly detected as described above. In addition, when the boom is tilted down and the lower surface of the worktable is pressed against the ground or the like, there is a demand that this be detected. However, when the moment is directly detected, such detection is difficult.

[0005] Under such circumstances, a device for directly detecting the workbench load has been conventionally proposed. As an example, a work table is slidably mounted vertically via a roller slider mechanism with respect to the vertical post at the end of the boom, and a spring is provided to urge the work table upward with respect to the vertical post, There is a configuration in which, when the work table loading load increases and the work table moves downward by a predetermined amount or more against the spring urging force, this is detected by a limit switch. However, in this configuration, since the roller slider mechanism is large and has a large weight, there is a problem that the weight of the worktable increases and the product cost increases.

The present invention has been made in view of such a problem.
An object of the present invention is to provide a workbench load detection device having a relatively simple configuration and capable of directly detecting a workbench load.

[0007]

In order to achieve the above object, a workbench load detecting device according to the present invention comprises a post member attached to a tip of a boom, and a post member attached to the post member so as to be vertically swingable. And a work table attached to the tip of the parallel link mechanism, and furthermore, the work table is disposed between the work table and the post member. It is provided with regulating means for regulating the swinging movement up and down, and load detecting means for detecting the workbench load based on the load acting on the regulating means.

[0008] If the workbench load detecting device having such a configuration is used, the workbench is supported by the parallel link mechanism with respect to the post member, and the structure for attaching the workbench to the post member is simple. In addition, the workbench swings downward due to its own weight only by mounting with the parallel link mechanism. Therefore, means for regulating this, such as a spring, is required. In addition, it is possible to reliably detect.

In the above construction, the regulating means is provided with elastic support means (for example, a spring) which urges the work table upward with respect to the post member and supports the load table, and the load detecting means is provided by the elastic support means. The work platform load may be detected based on the amount of downward movement of the work platform against the urging force. In this configuration, the workbench is moved downward against the support force of the elastic support means, but the amount of movement is proportional to the elastic urging force, so that the workbench load can be easily detected based on this movement amount. .

The first elastic support means for urging the worktable upward with respect to the post member to support the regulating means, and the second elastic support means for urging the worktable downward with respect to the post member to support the worktable. Means. In this case, the load detecting means detects the workbench loading load based on the amount of downward swing movement of the worktable against the upward biasing force of the first elastic support means, and detects the downward load by the second elastic support means. The workbench pressing load can be detected based on the amount of upward movement of the workbench against the urging force.

[0011] The restricting means may be configured to include a connecting member for connecting the post member and the worktable to restrict the operation of the parallel link mechanism. In this case, the load detecting means
A workbench load is detected based on an axial force acting on the connecting member.

[0012] In the above configuration, it is preferable that the post member is configured to be horizontally rotatable with respect to the tip of the boom. Thereby, the worktable can be swung freely to improve the workability. In this case, the necessary functions can be obtained with a simple configuration in which the worktable is supported via a horizontally linkable post member via a parallel link mechanism. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an aerial work vehicle having a workbench load detection device according to the present invention.
The aerial work vehicle is configured to include a swivel 3 that is horizontally rotatable on a vehicle body 2 of a truck vehicle having a driving cabin 1. A boom 4 is pivotally attached to the swivel 3, and the boom 4 is raised and lowered by a lifting cylinder 5. As shown, the boom 4 has a base boom 4a, an intermediate boom 4b, and a distal boom 4c, and is nested, and is telescopically operated by a built-in telescopic cylinder (not shown). Further, a boom head 4d is attached to the tip of the boom 4.

A support member 7 is attached to the boom head 4d so as to swing up and down, and the support member 7 is integrally provided with a vertical post extending upward. The support member 7 is configured to swing up and down with respect to the boom head 4d by the upper leveling cylinder 6a.
A lower leveling cylinder 6b is provided between the boom 4 and the swivel base 3, and the lower leveling cylinder 6b and the upper leveling cylinder 6a act to operate the boom 4
Swing control (leveling control) of the support member 7 is performed so that the vertical post always faces vertically upward regardless of the undulation angle of the support member 7.

A post member 8 is attached by fitting to a vertical post of the support member 7, and the post member 8 is horizontally rotatable about the vertical post. A worktable 10 is attached to the post member 8 via a parallel link mechanism 9, and the worktable 10 swings up and down to some extent under the action of the parallel link mechanism 9.

The operation of the aerial work vehicle having such a configuration will be described. The aerial work vehicle can be run in a retracted state in which the boom 4 is fully retracted, laid down, and placed on the boom receiver 16. When the vehicle travels and moves to the work site in this manner, first, the outrigger jack 15 is extended to lift and support the vehicle body 2. next,
An operator gets on the worktable 10 and operates an operating device (not shown) provided on the worktable 10 to control the turning of the swivel 3 and the up / down and extension / retraction operations of the boom 4. The work table 10 is moved to a desired height while being on board. This allows the worker to work at a desired height.

When the work table 10 is moved to a high place in order to perform work at a high place in this way, the tipping force acting on the vehicle body 2 by the weight of the work table 10, the boom 4 and the like according to the moving position of the work table 10. The moment changes. In this aerial work vehicle, there is provided an overturn prevention device that regulates the operation of the boom 4 or the like such that the overturning moment increases when the overturning moment exceeds the stability allowable range by the outrigger jack 15. At this time, since the overturning moment is greatly affected by the weight of the operator who is on the worktable 10 and the weight of tools and devices mounted thereon, the mounting allowable load of the worktable 10 is set. A warning is issued when the load on the vehicle exceeds the allowable load. For this reason, the work platform aerial vehicle of this example is provided with a workbench load detection device that detects the load on the workbench 10.

This workbench load detecting device will be described below. First, a support structure of the worktable 10 for the post member 8 will be described with reference to FIG. Upper and lower link support members 8a and 8b are fixed to the post member 8 at an interval in the vertical direction, and the base ends of the upper and lower link members 9a and 9b are swingable up and down on these link support members 8a and 8b, respectively. Being pivoted. The distal ends of the upper and lower link members 9a and 9b are integrally formed with the work table 10 and are pivotally connected to a connecting portion 10b projecting sideways so as to be vertically swingable. As described above, the base end and the distal end are the link support members 8.
The upper and lower link members 9a and 9b extend in parallel at predetermined intervals in the vertical direction while being pivotally connected to the connecting portions 10a and 8b and the connecting portion 10b, and a parallel link mechanism 9 is configured.

For this reason, the work table 9 can be moved up and down with respect to the post member 8 in accordance with the swing motion of the parallel link mechanism 9. Further, the worktable 10 can be horizontally rotated (swinged) around the support member 7 by the post member 8 horizontally rotating with respect to the support member 7. However, only by the support by the parallel link mechanism 9, the parallel link mechanism 9 swings downward due to the weight of the worktable 10, and the worktable 10
Is moved down. For this reason, a support spring 11 is provided between the support arm 10a extending integrally from the worktable 10 and the upper link support member 8a. The support spring 11 acts on the upper link support member 8a so as to push the worktable 10 upward through the support arm 10a.
When the load 0 is zero or small, the workbench 10 is held at the position shown in FIG.

On the other hand, when the load or mounting load W of the worktable 10 increases, the load W acts on the support spring 11 via the support arm 10a, and compresses and deforms the support spring 11. Thereby, as shown in FIG. 2B, the parallel link mechanism 9 swings, and the worktable 10 moves down by the amount of compressive deformation of the support spring 11. Here, an overload detection limit switch 12 is provided on the upper link support member 8a so as to face the support arm 10a, and the support arm 10a moves when the workbench 10 moves down due to the compression deformation of the support spring 11. The overload detection limit switch 12 is pushed to turn it on. As described above, the load W of the work table 10 when the support arm 10a turns on the overload detection limit switch 12 is set to be an allowable load. It is possible to detect that the load of 10 exceeds the allowable load. Note that the ON / OFF relationship of the overload detection limit switch 12 may be reversed.

The area around the overload detection limit switch 12 is shown in detail in FIG. 2C. As can be seen from this configuration, the overload detection limit switch 12 is mounted on the mounting portion of the support spring 11. With this configuration, only the displacement amount of the support spring 11 can be detected, and the detection accuracy can be improved.

Next, a different example of the workbench load detecting device according to the present invention will be described with reference to FIG. In this example, a support spring unit 20 and an overload detection limit switch 30 are used instead of the support spring 11 and the overload detection limit switch 12 in the examples shown in FIGS.
Are arranged between the support arm 10a of the worktable 10 and the upper link member 8a as shown in the figure.

The support spring unit 20 is fixed to a boss 21 fixed to the upper surface of the upper link support member 8a via a pivot pin 21a and to a lower surface of the support arm 10a. And a spring support rod 25 pivotally connected to the boss 24 via a pivot pin 24a. The spring holding tube 22 extends upward with the pivotal connection with the boss 21 downward, and a cover plate 22a is fixed to the upper end. The spring support rod 25 extends downward with the pivotal connection with the boss 24 upward, and protrudes into the spring holding tube 22 through a through hole formed in the center of the cover plate 22a. A spring support member 26 is attached to a lower end of the spring support rod 25, and a side end of the spring support member 26 protrudes outward from the spring holding tube 22, and is attached to one end (the right end in the figure). A detection cam 27 is attached. The detection cam 27 is formed in a plane shape in which an intermediate portion 27b extends vertically, and has upper and lower tapered portions 27a, 27a at upper and lower ends.
27c is formed as shown.

An overload detection limit switch 30 is attached to the upper link member 8a via an attachment member 35 so as to face the detection cam 27 from the side. The overload detection limit switch 30 has a switch body 31 protruding toward the detection cam 27. When the switch body 31 is pressed into contact with the planar intermediate portion 27c of the detection cam 27, the switch body 31 is turned off, and a vertical taper is formed. The switch body 31 is pushed out and turned on in a state where the switch body 31 is in contact with one of the portions 27a and 27c. The ON / OFF setting of the limit switch 30 may be reversed.

On the other hand, in the spring holding tube 22, the lower compression spring 23a is sandwiched between the cover plate 22a and the spring support member 26 and located on the spring support rod 25.
The upper compression spring 23b is disposed between the boss 24 and the cover plate 22a, and is located above the spring support rod 25. Therefore, when the support arm 10a is moved downward with respect to the upper link support member 8a, the upper compression spring 23b is compressed by the boss 24, and when the support arm 10a is moved upward, the lower compression spring 23a is compressed.

In the workbench overload detecting device having such a configuration, the load W of the workbench 10 is adjusted by the support arm 10a.
And acts on the upper compression spring 23b from the boss 24 via the boss 24 to compress it. For this reason, as the load W of the worktable 10 increases, the upper compression spring 23b is compressed, the support arm 10a moves down, and the worktable 10 moves down by the action of the parallel link mechanism 9. At this time, the detection cam 27 moves down together with the spring support rod 25 connected to the boss 24. Here, when the load W becomes the allowable load,
As shown in FIG. 3B, the upper taper portion 2 of the detection cam 27
7a is the switch body 3 of the overload detection limit switch 30
The upper compression spring 23b is set at a position where the upper compression spring 23b comes into contact with the first compression spring 23b. For this reason, the overload detection limit switch 3
By detecting that 0 has been turned on from off, it is possible to detect whether or not the loaded load W of the worktable 10 has exceeded the allowable load.

On the other hand, there is a case where the bottom surface of the worktable 10 is pressed against the ground, a building, or the like by operating the boom 4 in a falling operation or a contracting operation. In this case, the work table 10
Receives a force F that is pushed upward. This pushing-up force F also acts as a force for pushing up the support arm 10a, and the spring support rod 25 is pulled up to move the lower compression spring 2
3a is compressed. When the push-up force F reaches an allowable value, as shown in FIG. 3C, the lower taper portion 27c of the detection cam 27 is brought into a position where it comes into contact with the switch body 31 of the overload detection limit switch 30. Upper compression spring 23
b is set. Therefore, it can be detected that the overload detection limit switch 30 has been turned on from off, and whether the pushing force F of the workbench 10 has exceeded an allowable value can be detected.

Next, a third embodiment of the workbench load detecting device according to the present invention will be described with reference to FIG. In this example, a post member 18 is attached to a vertical post 7a of a support member 7 attached to the boom head 4d so as to be vertically swingable so as to be horizontally pivotable. A work table 10 ′ is attached to the post member 18 via a link mechanism 19. The link mechanism 19 has both ends of the post member 1
Upper and lower link members 19a and 19b pivotally connected to the connecting member 8 and the connecting portion 10b 'of the worktable 10', and extend obliquely between the link members 19a and 19b, and both ends thereof are post members 18 respectively. And an intermediate link member 19c pivotally connected to the connecting portion 10b '.
In this link mechanism 19, the swing of the upper and lower link members 19a and 19b is restricted by the intermediate link member 19c, and the worktable 10 'does not swing vertically as in the above-described example.

In order to detect the loaded load or the pressing load of the worktable 10 ', an axial force detector such as a strain gauge for detecting an axial force acting on the intermediate link member 19c is provided. Here, the upper and lower link members 19
a and 19b extend horizontally, and only a horizontal force acts on this member.
By detecting the axial force 9c, it is possible to detect the work table loading or the pressing load. The upper and lower link members 19a, 19
When b is disposed obliquely, an axial force detector is also provided for these, and the work platform loading or pressing load is obtained from the axial forces of the three link members 19a, 19b, and 19c in consideration of the moment balance. Can be.

[0030]

As described above, according to the present invention,
The work table is supported by the parallel link mechanism with respect to the post member, and the structure for attaching the work table to the post member is simple. In addition, since the worktable swings downward due to its own weight only by mounting with the parallel link mechanism, a means for regulating this, for example, a spring is required,
The work table load can be easily and reliably detected from the load acting on the restricting means.

In the above construction, the regulating means is provided with elastic support means (for example, a spring) for urging the worktable upward with respect to the post member and supporting the work table, and the load detecting means is provided by the elastic support means. The work platform load may be detected based on the amount of downward movement of the work platform against the urging force. In this configuration, the workbench is moved downward against the support force of the elastic support means, but the amount of movement is proportional to the elastic urging force, so that the workbench load can be easily detected based on this movement amount. .

The first elastic support means for supporting the work table by urging the work table upward with respect to the post member, and the second elastic support means for supporting the work table by pressing the work table downward with respect to the post member. Means. In this case, the load detecting means detects the workbench loading load based on the amount of downward swing movement of the worktable against the upward biasing force of the first elastic support means, and detects the downward load by the second elastic support means. The workbench pressing load can be detected based on the amount of upward movement of the workbench against the urging force.

The restricting means may have a connecting member for connecting the post member and the worktable to restrict the operation of the parallel link mechanism. In this case, the load detecting means
A workbench load is detected based on an axial force acting on the connecting member.

[0034] In the above configuration, it is preferable that the post member is configured to be horizontally pivotable with respect to the tip of the boom. Thereby, the worktable can be swung freely to improve the workability. In this case, the necessary functions can be obtained with a simple configuration in which the worktable is supported via a horizontally linkable post member via a parallel link mechanism. .

[Brief description of the drawings]

FIG. 1 is a front view showing an aerial work vehicle having a workbench load detection device according to the present invention.

FIG. 2 is a front view showing a configuration of a workbench load detecting device according to the first embodiment of the present invention.

FIG. 3 is a front view illustrating a configuration of a workbench load detection device according to a second embodiment of the present invention.

FIG. 4 is a front view illustrating a configuration of a workbench load detection device according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 4 boom 7 support member 8 post member 9 parallel link mechanism 10 work table 10a support arm 11 support spring 12 overload detection limit switch 20 support spring unit 22 spring holding tubes 23a, 23b upper and lower compression springs 25 spring support rod 27 detection cam 30 Overload detection limit switch

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroaki Seki 414-1 Higashimine Sugawa, Shinji-mura, Tone-gun, Gunma Prefecture Inside the Aichi Corporation Shinji Works (72) Inventor Masakazu Yake 1152 Yamashita, Ryuji, Ryuji, Ageo-shi, Saitama No. 10 Aichi Corporation Ageo Works (72) Inventor Yoshito Nohara 41-1, Higashimine Sugawa, Niimura, Tone-gun, Gunma Pref. Inside Aichi Corporation Shinji-ko, Co., Ltd. (72) Inventor Takashi Kawasumi Shinji-mura, Tone-gun, Gunma 414-1 Ogawa Tomine Sukawa F-term (reference) in Aichi Corporation Shinji Works 3F333 AA08 AA15 AB01 AC01 AC08 BA12 BB03 BB09 BB23 BD02 BE02 CA15 FA09 FD06 FE03 FE04

Claims (4)

[Claims] 1. A post member attached to a tip of a boom, a parallel link mechanism attached to the post member so as to swing vertically, and a work table attached to a tip of the parallel link mechanism. A restricting means disposed between the work table and the post member, for restricting the work table from swinging up and down with respect to the post member by the parallel link mechanism; and A workbench load detecting device, comprising: a workbench load detecting means for detecting the workbench load based on a load acting on the workbench. 2. The control device according to claim 1, wherein the restricting unit includes an elastic supporting unit that urges the work table upward with respect to the post member and supports the working table. The workbench load detection device according to claim 1, wherein the workbench load is detected based on an amount of downward swing movement of the workbench against a force. 3. The first elastic support means for urging the worktable upward against the post member and supporting the worktable upward, and the restriction means for urging the worktable downward against the post member. And a second elastic support means for supporting the work table, wherein the load detecting means is configured to move the work table based on an amount of downward swing movement of the work table against an upward biasing force of the first elastic support means. It is configured to detect a loaded load and to detect the work platform pressing load based on an amount of upward swing movement of the work table against a downward biasing force of the second elastic support means. The workbench load detecting device according to claim 1, wherein 4. The apparatus according to claim 1, wherein the restricting means includes a connecting member that connects the post member and the work table to restrict the operation of the parallel link mechanism. The load detecting means acts on the connecting member. The work platform load detection device according to claim 1, wherein the work platform load is detected based on an axial force to be applied.