JPH0210888B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that can automatically measure the amount of cargo inside a bucket during cargo handling operations using a bucket loader or the like.

When loading earth and sand, iron ore, pulp chips, etc. onto a dump truck using a bucket loader, accurately grasping the loaded weight is an extremely important factor in increasing work efficiency and managing work. be.

However, conventionally, for example, when measuring the weight loaded onto a dump truck by a bucket loader, the weight of each truck was measured using a general load meter, and then the truck weight was subtracted from the measured value to determine the actual loaded weight. It is being calculated.

For this reason, it is extremely difficult to accurately and immediately grasp the loaded weight. For example, even if it is possible to accurately determine whether or not a truck is overloaded, it requires considerable effort and time. In addition, there is a risk that the calculation of the loading weight as mentioned above may be incorrect.
There are various disadvantages.

Therefore, a system that uses a microcomputer to automatically measure the net load in the loader bucket and automatically determine whether or not there will be an overload when loading the measured weight onto a truck, etc. is proposed. Already developed.

However, in the case of such a system, the cost is large and the installation location in the loader etc. is limited to the inside of the cabin, so it tends to lack versatility, such as being applicable only to large model loaders etc.

This invention was made in view of the above circumstances, and its main purpose is to provide a hydraulically actuated cargo loader that can automatically measure the load amount in a bucket with high precision, is low cost, can be applied to any type of bucket loader, etc., and is easy to handle. To provide automatic weight measurement equipment.

Another object of the present invention is to provide an expensive hydraulically actuated cargo capacity system, which is extremely effective in preventing overloading during loading and unloading onto dump trucks, etc., by being able to instantly grasp the exact load capacity in a bucket. To provide automatic measuring equipment.

In order to achieve the above object, the present invention is characterized in that the net load inside the bucket can be reliably and automatically measured from the respective hydraulic pressures of both the lift and tilt cylinders of the bucket drive system.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

In Figure 1, 1 is the lift arm of the bucket loader, 2 is the bucket loader, 3 is the lift cylinder, and 4 is the lift arm of the bucket loader.
is a tilt cylinder, and a position sensor 5 for detecting the vertical position of the bucket belt 2 is provided near the base end pivot portion of the lift arm 1.

In the illustrated example, the sensor 5 consists of a pair of upper and lower limit switches 5a and 5b installed on opposite sides of the bucket loader.

These limit switches 5a, 5b are pushed by a cam piece 5c provided on the lift arm 1. In this case, the upper limit switch 5a is turned on by the cam piece 5c when the bucket 3 is in a certain raised position, and the lower limit switch 5b is turned on when the bucket is at a certain lowered position.

On the other hand, as detailed in Fig. 2, the lift cylinder 3
and each bottom side chamber 3a of the tilt cylinder 4,
4a is connected to a pressure-balanced volumetric metering cylinder 6 via switching valves V1 and V2 of the respective systems.

This metering cylinder 6 is configured to include a pair of pistons 7 and 8 facing each other on the same axis, and a spring 9 interposed between these pistons as an elastic member. is formed to have a larger diameter than the lift-side piston 7.

This metering cylinder 6 has pressure oil from the lift cylinder 3 in a lift-side chamber 6a partitioned by a lift-side piston 7, and pressure oil from the tilt cylinder 4 into a tilt-side chamber 6b partitioned by a tilt-side piston 8. Pressure oil is connected to switching valves V1 and V2
It operates as described below by being introduced through the .

Each of the switching valves V1 and V2 in the illustrated example is a 3-port, 3-position closed center electromagnetic valve that operates when a signal is input from limit switches 5a, 5b in FIG. When a signal is input from the upper limit switch 5a, each bottom chamber 3a of the lift and tilt cylinders 3, 4,
The position is switched to connect the primary side oil passages L1, L4 from 4a and the secondary side oil passages L2, L5 leading into the chambers 6a, 6b of the metering cylinder 6. Further, when a signal is input from the lower limit switch 5b, the position is switched to connect the secondary oil passages L2, L5, respectively, and the return oil passages L3, L6, respectively.

Therefore, when the bucket 2 loaded with cargo such as earth and sand, iron ore, pulp chips, etc. is lifted up to a predetermined raised position, the upper limit switch 5a at that position is turned on, and a signal from the switch turns on each switching valve V1, V2. is switched and the mutual chambers 3a and 6a and 4a and 6b in the lift and tilt cylinders 3, 4 and the metering cylinder 6 are switched.
By communicating with each other, pressure oil from each of the lift and tilt cylinders 3 and 4 is introduced into each chamber 6a and 6b of the metering cylinder 6.

In this case, the hydraulic pressure of the lift cylinder 3 increases in proportion to the amount of cargo load inside the bucket 2, and increases as the center of the cargo load moves toward the tip of the bucket.

Therefore, the hydraulic pressure of the tilt cylinder 4 also increases in proportion to the movement of the load center toward the tip of the bucket.

Such a lift and tilt cylinder 3,
When the pistons 7 and 8 of the metering cylinder 6 individually receive the respective hydraulic pressures of the metering cylinder 6, the pistons move.

In this case, the amount of movement of the lift-side piston 7 is determined by the differential pressure between the oil pressure from the lift cylinder 3 and the oil pressure from the tilt cylinder 4 via the spring 9. For this reason, each component of the metering cylinder 6 is designed and adjusted so that the volume of the lift-side chamber 6a is proportional to the net cargo load in the bucket 2.

As a result, the pistons 7 and 8 receive hydraulic pressure from the lift and tilt cylinders 3 and 4 in the direction of compression of the spring 9, resulting in movement of the load center included in the hydraulic pressure from the lift cylinder 3. The increased pressure is canceled out by the hydraulic pressure from the tilt cylinder 4 and the force of the spring 9. This automatically corrects the movement of the load center.

Thus, the lift-side piston 7 is a lift cylinder 3 proportional to the net load in the bucket 2.
Since the piston is moved only by hydraulic pressure, the amount of piston movement is displayed on the load amount display means 10 as the net load amount in the bucket.

As shown in more detail in FIG. 3, the illustrated display means 10 includes a rack 10a integrally connected to the lift-side piston 7, and a pinion 10b meshed with the rack 10a.
It consists of a pointer 10c integrated with the shaft of the pinion, and a scale plate 10d for weight display.

Therefore, the rack 10a that moves to follow the lift-side piston 7 rotates the pinion 10b and moves the pointer 1.
0c indicates the scale of the scale plate 10d, thereby displaying the net load amount in the bucket based on the amount of movement of the piston 7.

Such weight display is canceled when the bucket 2 discharges the cargo and descends to a predetermined position.

That is, when the bucket 2 is lifted down to a predetermined lowering position, the lower limit switch 5b is activated.
By being turned ON, each switching valve V1, V2 is switched to the secondary oil passage L2, L5 and the return oil passage L of the respective system.
3 and L6, each chamber 6 of the metering cylinder 6
The pressure oil in a and 6b is drained by the elastic force of the spring 9, thereby eliminating the weight display in preparation for the next measurement.

However, in this case, the pressure oil in the tilt-side chamber 6b of the metering cylinder 6 is directly drained, but the return oil path L3, which is the drain system of the lift-side chamber 6a, has a flowmeter-type integrated weight meter on the way. 11 is provided, each time the bucket 2 repeats loading and unloading for cargo handling, the net load inside the bucket is determined by the cumulative weight scale 11 based on the drain oil flow rate from the lift side chamber 6a. The total amount will be displayed.

Therefore, for example, when a bucket loader loads cargo onto a dump truck, the total weight of the load can be immediately confirmed using the integrating weight scale 11, and the daily workload of the bucket loader can be easily managed.

In addition, during the loading and unloading process onto dump trucks, etc.
Load amount display means 10 for metering cylinder 6
By comparing the weight values displayed on each of the weight scales 11 and 11, it can be easily determined whether or not the cargo to be loaded into the truck or the like is overloaded.

Therefore, it is possible to prevent overloading onto trucks and the like.

Note that the load amount display means 10 and the cumulative weight scale 11 may be digital displays, and it is also possible to display whether or not the load amount is appropriate for a dump truck etc. by the digital display or by lighting a lamp. It is.

As described above, in this invention, the net load amount in the bucket is automatically corrected for the movement of the center of gravity of the cargo in the bucket by the metering cylinder operated by the hydraulic pressure introduced from both the lift and tilt cylinders of the bucket drive system. Can be measured automatically.

Therefore, the configuration of the entire device is greatly simplified, and can be applied to any type of loader at low cost, and is easy to handle.

Furthermore, since the accurate amount of cargo inside the bucket can be grasped instantly, it greatly contributes to the proper management of the cargo when loading and unloading onto dump trucks and the like.

[Brief explanation of drawings]

The drawings show preferred embodiments of the present invention; Fig. 1 is a side view of the lift arm of a bucket loader, Fig. 2 is a configuration diagram of an automatic loaded weight measuring device, and Fig. 3 is an enlarged cross-section of a metering cylinder in the same device. It is a diagram. 2 is a bucket, 3 is a lift cylinder, 4 is a tilt cylinder, 6 is a metering cylinder, 7, 8
9 is a piston, 9 is a spring illustrated as an elastic member, and V1 and V2 are switching valves.

Claims (1)

[Scope of Claims] 1. A device capable of automatically measuring the amount of cargo load inside a bucket from the hydraulic pressure between a lift cylinder and a tilt cylinder of a bucket drive system when the bucket is set at a fixed height position. A tilt cylinder is equipped with a pair of pistons facing each other via a resilient member, and the hydraulic pressure of a lift cylinder proportional to the amount of load inside the bucket is applied to one piston, and the hydraulic pressure of the lift cylinder is proportional to the movement of the center of gravity of the amount of load inside the bucket. A pressure-balanced volumetric metering cylinder configured to apply hydraulic pressure to the other piston in the direction of compressing the elastic member through the switching valve of each system, and a hydraulic pressure of the lift cylinder in this metering cylinder. A load amount display means for taking out and displaying the amount of movement of the piston on the acting side as a net load amount in the bucket, and automatically correcting the movement of the center of the load in the bucket and displaying the net load amount in the bucket. A hydraulically operated automatic load weight measuring device characterized by: 2. In the device according to claim 1,
A hydraulically actuated automatic load weight measuring device characterized by having means for sequentially automatically measuring the return flow rate of pressure oil introduced from a lift cylinder to a metering cylinder and cumulatively displaying a net load amount in a bucket. 3. In the device according to claim 1,
The switching valve is configured to connect the lift and tilt cylinders and the metering cylinder at a predetermined raised position of the bucket, and to connect the metering cylinder to the drain system return oil path at a predetermined lowered position of the bucket. A hydraulically operated automatic load weight measuring device.