JPH0430237Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a moment limiter for an aerial work vehicle.

In a moment limiter that detects the load from the stress transmission member of the upright cylinder of an aerial work vehicle that maintains the balance of the work platform using a balance holding device that connects a pair of balance holding cylinders in a closed circuit, the boom The balance-maintaining cylinder installed between the boom and the swing base acts as a load when raising the boom, and acts to support the load when lowering the boom. If the load detected from the stress transmission member of the cylinder is directly compared with the allowable load, there will be problems such as the aerial work vehicle stopping operating with more margin than necessary from the overturning limit, or exceeding the overturning limit. It was hot.

The present invention was made in order to solve the above problem, and the purpose is to provide a moment limiter for an aerial work vehicle that always operates accurately by correcting the influence of the balance holding cylinder on the detected load. That is.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in Fig. 1, the aerial work vehicle has a boom 3 whose base is pivotably supported on a swivel base 2 provided on a vehicle body 1, and the boom 3 has a built-in telescopic device (not shown). 2), it expands and contracts in a telescopic shape, and also rises due to the expansion and contraction of the raising cylinder 4, which is attached between the swing base 2 and the boom 3 with both ends pivotally supported. A workbench 5 is pivotally supported at the tip of the boom 3,
The workbench 5 has a balance holding cylinder 6 which is mounted between the swing base 2 and the boom 3 with its both ends pivoted, and a balance maintenance cylinder 6 which is mounted with its both ends pivoted between the tip of the boom 3 and the workbench 5. The boom 3 is always maintained in a balanced state regardless of the raising operation of the boom 3 by the balance maintaining device which is connected to the balance maintaining cylinder 7 in a closed circuit.

The load acting on the aerial work vehicle is detected by a strain gauge attached to a stress transmission member such as a pivot pin or rod of the lifting cylinder 4, but when the boom 3 is raised, the balance maintaining cylinder is used. 6
acts as a load, and when the boom 3 is raised and lowered, the balance maintaining cylinder 6 operates to support the load, so the detected load depends on the raised position of the boom 3, as shown in Figure 2. When the boom 3 is raised, it becomes larger than the actual value, and when the boom 3 is raised and lowered, it becomes smaller than the actual value.

Figure 3 is a block diagram of the moment limiter, which detects whether the boom is in the raising or lowering operation state from the movement of the raising operation lever or the movement of the boom itself. The shape detector 8 is connected to the load correction section 11, and the load correction section 1
In 1, when the boom is in the raising operation state, the load signal detected by the load detector 9 is as follows.
As shown in Figure 2, a preset constant value is subtracted, and when the boom is in the lowering operation state, the preset constant value is added to correct the load. The signal is corrected. The load correction section 11 is connected to the comparator 12 together with the allowable load calculator 10, and the comparator 12 is connected to the alarm device 1.
3 and a deactivation device 14.

With the above configuration, the load signal detected by the load detector 9 is subjected to load correction according to the boom raising operation state (when the boom raising operation is stopped, it depends on the operation state before stopping). The comparator 12 compares the corrected load signal with the allowable load signal calculated by the allowable load calculator 10, and when the load approaches or reaches the allowable load, an alarm is activated. 13 and the operation stop device 14 are activated to issue an alarm and stop the operation of the aerial work vehicle toward the overturning side.

As described above, according to the present invention, the detected load is compared with the allowable load after correcting the influence of the balancing cylinder of the balancing device of the workbench.
The present invention provides a moment limiter for an aerial work vehicle that always operates accurately, without causing the vehicle to exceed the overturning limit or stop operating with an unnecessarily high margin from the overturning limit. is effective in improving the safety and workability of aerial work vehicles.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is a side view showing the working condition of the aerial work vehicle, Fig. 2 is a graph showing the relationship between working radius and load, and Fig. 3 is a block line of the moment limiter. It is a diagram. 2...Swivel base, 3...Boom, 4...Elevating cylinder, 5...Working platform, 6, 7...Equilibrium holding cylinder, 8...Elevation detector, 9...Load detector, 1
0... Allowable load calculator, 11... Load correction section, 1
2... Comparator, 13... Alarm, 14... Operation stop device.

Claims (1)

[Scope of utility model registration request] The boom is pivoted to the swing base so that it can be raised freely, both ends of the raising cylinder that raises the boom are pivoted to the swing base and the boom respectively, and a workbench is pivoted to the tip of the boom so that the boom and the work can be raised. A balance maintaining device that connects the balance maintaining cylinders installed between the platforms and between the boom and the rotating base through a closed circuit maintains the balance of the work platform regardless of the raising operation of the boom, and applies transmission of the raising cylinder. A comparator compares the load signal detected by the load detector that detects the load from the member with the allowable load signal calculated by the allowable load calculator, and when the load approaches or reaches the allowable load, an alarm or high Raising detection detects whether the boom is in the raising or lowering state in the moment limiter of the aerial work vehicle, which activates the stop device that stops the operation of the work vehicle. The boom detector is connected to the load detector, and the load detected by the load detector is subtracted by a preset constant value depending on the boom raising operating state and raising lowering operating state. Alternatively, a moment limiter for an aerial work vehicle is provided, comprising a load correction section that performs addition and correction.