JPH0546896U - Safety equipment for aerial work vehicles - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] In an aerial work vehicle, it is possible to accurately detect overloading on a workbench and perform accurate and safe moment regulation. [Structure] The load detector 15 is sandwiched between the lower portion 6b of the vertical post and the lower surface of the workbench mounting bracket 7.
The load detector 15 is configured to detect the load of the workbench 8 from the clamping force applied from the mounting bracket 7. The detected load of the workbench detected by the load detector 15 is compared with the allowable load preset by the comparator, and when the detected load exceeds the allowable load, the comparator outputs an alarm signal to the alarm means. , The alarm is activated by the alarm buzzer and alarm lamp to stop the boom operation.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a safety device for preventing overloading on a work platform in an aerial work vehicle having a work platform mounted on a tip of a boom that can be freely undulated, extended and retracted, through a support post.

[0002]

[Prior Art]

 In an aerial work vehicle that has a work platform on which an operator can ride at the tip of a boom that can be undulated and expanded and contracted, etc., in the falling direction that is applied to the vehicle body in accordance with changes in the boom undulation angle and extension amount, Since the moment changes, it has been conventionally known that the moment is regulated so as to prevent the boom from undulating and expanding and contracting so that the moment does not exceed a predetermined value. Such a moment in the falling direction changes not only according to the hoisting angle of the boom, the amount of extension, etc., but also due to the load on the workbench (the weight of the workbench and the load on the workbench). Therefore, it is necessary to regulate the moment.

From the above, the load on the workbench has been taken into consideration even in the conventional moment regulation. For example, a workbench is attached to the tip of the boom via a spring so that the spring flexes according to the load on the workbench so that the workbench moves up and down. There is a limit switch at the lower position. In this case, when the load on the work table exceeds the limit load, the limit switch turns on, so an alarm is issued in response to this to prevent overloading on the work table and to ensure safe operation. It is designed to regulate the moment.

[0004]

[Problems to be solved by the device]

 However, in the case of this aerial work vehicle, since the workbench is supported by the spring, the workbench is likely to move up and down, which gives an uncomfortable feeling to a worker who is on the workbench. There is a problem that is not so good. In addition, if an inertial force is applied to the workbench during operation of the boom, the amount of spring deflection increases due to this inertial force, and the limit switch is turned on even if the workbench load is within the limit. There is also the problem that there is. Furthermore, since the accuracy of the spring cannot be so high, there is a problem in that it is difficult to accurately prevent overloading because the load that causes the limit switch to turn on varies widely.

The present invention has been made in view of such a problem, and can accurately detect overloading on a workbench without supporting the workbench with a spring, and perform accurate and safe moment control. It is an object of the present invention to provide a safety device for an aerial work vehicle that is capable of performing the above.

[0006]

[Means and Actions for Solving the Problems]

 In order to achieve such an object, in the aerial work vehicle according to the present invention, the work platform is supported via a support post that is swingably attached to the front end of the boom. The vertical posts of the support posts are inserted into the insertion holes formed in the mounting bracket that is integrally provided on the workbench, and the workbench is attached to the support posts. Further, it has leveling means for vertically swinging the support posts so that the vertical post portions are held vertically, whereby the workbench is always held horizontally.

In the safety device according to the present invention, the load detector is arranged so as to be sandwiched between the lower portion of the vertical post and the lower surface of the mounting bracket in the aerial work vehicle having such a configuration. However, this load detector detects the load on the workbench from the clamping force applied from the bracket. The detected load of the workbench detected by the load detector is compared with the preset allowable load by the comparator, and when the detected load exceeds the allowable load, the comparator outputs an alarm signal. This alarm signal is input to the alarm means, and the alarm means issues an alarm with an alarm buzzer or an alarm lamp, or stops the boom operation to give an alarm.

[0008]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. An example of an aerial work vehicle having a safety device according to the present invention is shown in FIG. This aerial work vehicle has a swivel base 2 which is rotatable on a vehicle body 1, and a telescopic boom 3 is attached to the swivel base 2 so as to be capable of hoisting. The telescopic boom 3 is composed of a base boom 3a that is pivotally supported by a swivel base 2 by a pin 5 and can be raised and lowered, and a tip boom 3b that is expandable and contractable with respect to the base boom 3a. The tip boom 3b is made to extend and contract by an extendable cylinder (not shown) provided. In addition, the hoisting operation of the telescopic boom 3 is performed by the hoisting cylinder 4 arranged between the swivel base 2 and the base end boom 3a.

As shown in FIG. 2, a support post 6 is pivotally supported by a pin 3c and swingably supported up and down at the tip of the tip boom 3b. The support post 6 is a member that supports the workbench 8, and has a vertical post portion 6a. A mounting bracket 7 is integrally connected to the workbench 8, and a pair of upper and lower bracket plates 7a constituting the mounting bracket 7 are vertically penetrated to form an insertion hole 7b. The mounting bracket 7 is attached to the vertical post portion 6a so that the vertical post portion 6a is inserted into the insertion hole 7b, and as a result, the workbench 8 is supported by the support post 6.

As shown in FIG. 2, a supporting flange 6b is formed in the lower part of the vertical post portion 6a, and the mounting bracket 7 is mounted on the supporting flange 6b so that the vertical post portion 6a is mounted on the vertical post portion 6a. It is attached. However, at the time of this mounting, the load detector 15 composed of a ring disk-shaped load cell is mounted on the support flange 6b, and the mounting bracket 7 is mounted so as to be mounted on the load detector 15. . For this reason, the load detector 15 is sandwiched between the support flange 6b and the mounting bracket 7, and the load of the workbench 8 (the total load of the workbench 8 and the mounting bracket 7 and the load on the workbench 8 is combined). ) Are all added to the load detector 15. The load detector 15 is a load cell that detects the sandwiching load (compression load), and the load detector 15 can detect the load of the workbench 8.

The mounting bracket 7 is horizontally rotatable around the vertical post portion 6a. Therefore, the workbench 8 is vertically swingable together with the support post 6 around the pin 3c, and It is swingable (rotatable) in the horizontal direction about the vertical post 6a. Outriggers 9 are attached to the front, rear, left, and right of the vehicle body 1 at four positions to extend and support the vehicle body 1 during work.

[0012] Since a worker rides on the workbench 8, the workbench 8 must always be kept horizontal regardless of the ups and downs of the telescopic boom 3. For this reason, this aerial work vehicle is equipped with a leveling device including a lower leveling cylinder 11 and an upper leveling cylinder 12. As shown in FIG. 1, the lower leveling cylinder 11 is arranged between the swivel base 2 and the base end boom 3a, and the upper leveling cylinder 12 is arranged between the front end boom 3b and the support post 6. ing.

The bottom-side oil chambers of the lower leveling cylinder 11 and the upper leveling cylinder 12 communicate with each other, and the rod-side oil chambers of the lower leveling cylinder 11 and the upper leveling cylinder 12 communicate with each other. Therefore, for example, when the telescopic boom 3 is hoisted by the hoisting boom 4 and the lower leveling cylinder 11 is telescopically moved, the upper leveling cylinder 12 is telescopically operated in the opposite direction to the lower leveling cylinder 11, and the posture of the workbench 8 is increased. Is always held horizontally.

The aerial work vehicle constructed as described above is provided with a safety device for preventing overloading based on the load of the workbench 8 detected by the load detector 15. FIG. Will be described with reference to. This safety device has a comparator 16 for comparing the detected load of the workbench 8 detected by the load detector 15 with a preset allowable load, and when the detected load is equal to or larger than the allowable load, That is, when the load of the workbench 8 is overloaded, the comparator 16 outputs an alarm signal to the alarm means 17.

The alarm means 17 is a means for performing an alarm operation upon receiving this alarm signal. For example, an alarm buzzer 18a and an alarm lamp 18b are used to give an alarm to the operator to inform that the operator is overloaded and to activate the alarm. The operation of the controller 19 is controlled to stop the operation of the telescopic boom 3 to issue an alarm to the operator. As a result, work is not performed in the overloaded state, and safety is improved.

Further, in such an aerial work vehicle, the moment is regulated assuming that the load on the workbench 8 is equal to or less than the allowable load, and the allowable movement range of the workbench 8, that is, the work range is set. As mentioned above, since the overloaded state does not occur, safe moment regulation can be performed. However, when such a moment regulation is performed, the allowable load varies depending on the hoisting angle, extension amount, and turning angle of the boom 3, so in this example, the hoisting angle sensor 21, the extension amount sensor 22, and the turning angle sensor. The detection signal from 23 is input to the comparator 16 so that the allowable load becomes an optimum value in accordance with the hoisting angle, extension amount and turning angle of the boom 3, that is, the attitude of the boom 3. With this configuration, in the moment regulation, it is possible to set an effective and appropriate work range according to the attitude of the boom 3.

[0017]

[Effect of the device]

 As described above, according to the present invention, in an aerial work vehicle configured to support a workbench via a support post that is swingably attached to the tip of a boom, the lower part of the vertical post can be attached to the work platform. The load on the workbench is detected by the load detector that is placed so as to be sandwiched between the bracket and the lower surface of the bracket, and the detected load on the workbench detected in this way is compared with the allowable load preset in the comparator. In comparison, when the detected load exceeds the allowable load, the comparator outputs an alarm signal to the alarm means, and this alarm means issues an alarm, so the load on the workbench is overloaded. It is possible to reliably prevent work in high places without any change, and it is possible to improve work safety.

[Brief description of drawings]

FIG. 1 is an aerial work vehicle having a safety device according to the present invention.
It is a front view which shows an example.

FIG. 2 is an enlarged front view showing the periphery of a workbench of the aerial work vehicle.

FIG. 3 is a system diagram showing a configuration of a safety device according to the present invention.

[Explanation of symbols]

 1 vehicle body 2 swivel base 3 telescopic boom 4 hoisting cylinder 6 support post 7 mounting bracket 8 workbench 15 load detector

Claims (1)

[Scope of utility model registration request] 1. A boom having a boom mounted on a vehicle body, a support post vertically swingably mounted on a tip of the boom, and a work platform supported by the support post. The vertical post portion of the support post is attached to the support post by inserting the vertical post portion of the support post into the insertion hole formed by extending vertically in the mounting bracket integrally provided on the base. A safety device for an aerial work vehicle having leveling means for controlling the vertical swing of the support post so that the support post is held between the lower part of the vertical post and the lower surface of the mounting bracket. And a load detector for detecting the load on the workbench based on the clamping force received from the bracket, and the load detected on the workbench detected by the detector.
A comparator that outputs an alarm signal when the detected load exceeds the allowable load by comparing it with a preset allowable load, and an alarm means for receiving an alarm signal from the comparator and performing an alarm operation. A safety device for an aerial work vehicle having: