JPH048149Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a load indicating device used in hydraulic cranes and the like.

(Prior art) In conventional hydraulic cranes, a simple load indicator detects the operating pressure of the hydraulic motor that drives the winch drum, calculates the lifting load based on this operating pressure, and displays the load. ing. This is calculated from the detected operating pressure P to the winch drum hoisting torque T.
(T=Pq/2π, q: amount of oil required for one rotation of the motor) can be calculated, and from this the wire tension F (T=
This is because the lifting load can be calculated by calculating Fr, r: distance from the center of the winch drum to the center of the wire rope) and further multiplying this tension F by the multiplier of the wire rope.

However, the winding torque T (=Fr) mentioned above is
There is a problem in that the value changes depending on the layer of wire rope wound around the winch drum.
This is because the distance r from the wire drum center to the wire rope center described above changes. That is, even when lifting the same load, the load instruction will differ depending on the number of layers of wire rope wound around the winch drum.

As a conventional technology that solved this problem,
-There is a publication No. 25367. This is done by installing a device that detects the winding pressure of the winch motor as well as the thickness of the winding layer of the wire rope, and automatically corrects the winding pressure based on the thickness of the winding layer. to indicate the lifting load.

(Problems to be Solved by the Invention) However, the technique disclosed in Japanese Patent Publication No. 55-25367 can be said to be extremely superior in its concept.

However, in this type of simple load indicator that indicates the winch hoisting pressure as the crane lifting load, it is difficult to install a device that automatically corrects the indicated load according to the number of winding layers. Considering that the structure is complicated and the cost increases, it can be said that it is overequipped. This type of load indicator used in cranes and the like does not need to function as a measuring device to accurately measure the weight of a suspended load, but only needs to be able to determine the approximate weight.

Therefore, the present invention aims to provide a load indicator which has a simple structure by adding a few small details to the conventional load indicator, and which has higher accuracy than the conventional load indicator.

(Means for solving the problem) For this reason, in the present invention, the wire rope wound around the winch drum at the base end of the crane boom is guided to the boom tip side, and the wire rope is hooked from the boom tip side. The hydraulic crane is configured to lift and suspend a load by raising and lowering a hook by lifting and lowering a wire rope wound around the winch drum, and the hydraulic crane that drives the winch drum A load indicating device for a hydraulic crane has a load indicator that detects the operating pressure of the motor during hoisting and indicates this operating pressure as the crane's lifting load. The number of winding layers of the wire rope wound around the winch drum, where the ground height is a variable parameter, the ground height of the hook is constant, the boom length is also a plurality of predetermined constant boom lengths, and only the boom angle is determined. is determined as a variable parameter, and a winding layer number indicator is provided to indicate the number of winding layers for each predetermined boom length by a pointer that rotates in accordance with the boom angle. This shows the load scale for each number of winding layers.

(Function) Therefore, when looking at the lifting load, first confirm the current number of winding layers using the winding layer number indicator, and then read the scale display on the load indicator at that number of winding layers.

(Example) The configuration of the present invention will be described below based on an example shown in the accompanying drawings.

FIG. 1 shows a working state diagram of the crane of the present invention. In this crane 1, a column 3 is rotatably supported on a crane base 2. A boom device 4 is attached to the column 3 and a luffing cylinder 8 is attached to the column 3. It is pivoted so that it can rise and fall freely. This boom device 4
A first boom 5, a second boom 6 telescopically inserted into the first boom 5, and a third boom 7 telescopically inserted into the second boom 6.
It is made up of 9 is a winch drum, and a wire rope 1 is wound around this winch drum 9.
0 to the tip of the boom, and this wire rope 10
The hook 11 is suspended by the winch drum 9, and the hook 11 is raised and lowered by hoisting and lowering the winch drum 9 to lift and suspend the load. 12 is a load indicator that measures the lifting load of this crane.

Next, a hydraulic circuit diagram of the winch of this crane is shown in Fig. 2. That is, the pressure oil from the pump 13 is switched by the switching valve 14 to operate the hydraulic motor 15,
The winch drum 9 connected to this is driven. Pressure gauge 12 that serves as a load indicator for this crane
is inserted into the hoisting circuit side of the winch. That is, when the switching valve 14 is switched to 14a, the suspended load is hoisted up, and the operating pressure at this time is measured by the pressure gauge 12. Note that the winch stops at the neutral position 14b, and the suspended load is lowered when switched to 14c.

Now, in FIG. 1, the number of layers of the wire rope 10 wound around the winch drum 9 varies depending on the boom length, boom angle, and height of the hook 11 above the ground. Therefore, if the number of winding layers of the wire rope in any working posture is continuously detected and continuously indicated, the structure thereof becomes quite complicated.

In the present invention, the height of the hook 11 above the ground is set to a constant height H, and the boom length is set to the first stage boom (the third
boom 7 is completely retracted into the second boom 6 and the second boom 6 is also completely retracted into the first boom 5), two-stage boom (the third boom 7 is completely retracted into the second boom 6), the second boom 6 is fully extended from the first boom 5), the three-stage boom (the third boom 7 is fully extended from the first boom 5),
This second boom 6 is also fully extended from the first boom.
Only when the boom 5 is fully extended (the state in which the boom 5 is fully extended), only the boom angle is determined as a variable.

Incidentally, in this type of crane, a rated load indicator 16 consisting of a pointer 17 and a display plate 18 as shown in Fig. 3 is attached to the side of the boom (see Fig. 1), and the rated load indicator 16 consists of a pointer 17 and a display plate 18 as shown in Fig. 3. It is designed to indicate the rated load for the number of boom stages. That is, in Figure 3, when the boom angle is 1 degree, the rated load is 2.04 tons for the 1st stage boom (boom), and 2.04 tons for the 2nd stage boom (+boom).
0.78 tons, 3-stage boom (++ boom)
Each has a rated load of 0.48 tons. When the boom is raised at nearly 50 degrees, the rated load is 2.9 tons for a 1-stage boom, 1.5 tons for a 2-stage boom, and 0.8 tons for a 3-stage boom.

In the present invention, this rated load indicator is used as a wire rope winding layer number indicator.

That is, since the height of the hook above the ground is a constant height H, the number of winding layers of the wire rope is a variable of the boom angle and boom length. Therefore, the boom length is fixed to a 1-stage boom, a 2-stage boom, and a 3-stage boom. Therefore, the number of winding layers is determined by the boom angle. Therefore, the rated load indicator shown in FIG. 3 may be used to indicate the number of winding layers in accordance with the boom angle for each boom stage number.

A, B, C, and D in FIG. 3 indicate the number of winding layers; A indicates one layer, B indicates two layers, C indicates three layers, and D indicates four layers. In other words, for a 1-stage boom (boom), there are 4 layers of D at all boom angles, and for a 2-stage boom (+
For boom), there are 4 layers of D up to approximately 33 degrees, but when the boom angle is higher than that, 3 layers of C are used. With a 3-stage boom (++ boom), there are four layers of D up to about 19 degrees, but beyond that, there are three layers of C, and when it gets close to about 40 degrees, there are two layers of B, and then about 65 degrees. If it exceeds 1 layer, it becomes 1 layer of A. Therefore, by looking at this winding layer number indicator 16, the current number of winding layers for each boom stage number can be determined at a glance. However, in the state of the intermediate boom, for example, when the second boom 6 is extended by about half from the first boom 5, this winding layer number indicator 16 cannot directly continue the winding layer number at that time, but in this case, Considering the extension length of the intermediate boom, etc., this winding layer number indicator 16
You can make an analogy from. However, when measuring the lifting load of a crane, this problem can be solved by measuring the standard number of boom stages (1 stage, 2 stages, 3 stages) as much as possible.

Next, the load indicator 12 of the present invention is shown in FIG.

The scale plate of the load indicator 12 in this invention has the number of winding layers A (4 layers), B (3 layers), C (2 layers), and D (1 layer).
Provide a scale display for each load. In other words, when checking the current lifting load with the load indicator 12, first check the number of winding layers of the wire rope with the winding layer number indicator 16, and then read the load scale for that number of winding layers. .

Next, Figure 5 shows a conventional load indicator.
As a rule of thumb, the number of winding layers when using a crane is usually 3 layers, so the scale display was created based on the case of 3 layers. Therefore, the conventional scale display is the same as the three-layer scale display C of the scale display of the present invention (FIG. 4).

(Effects of the invention) According to the invention, the scale plate of the conventional load indicator can be changed to a scale plate that displays the load scale for each number of winding layers. This results in a load indicator that is more accurate than the load indicator of . Moreover, the winding layer number indicator for checking the winding layer number can be obtained by simply adding the winding layer number to the conventional rated load indicator, making it simple, inexpensive, and highly accurate. A load indicator was obtained, and its practical value can be said to be extremely large.

[Brief explanation of drawings]

Fig. 1 is an overall schematic diagram of a crane to which the present invention is applied, Fig. 2 is a hydraulic circuit diagram of the part that drives the winch of this crane, and Fig. 3 is an explanatory diagram of the winding layer number indicator 16 of the present invention. FIG. 4 shows a load indicator 12 of the present invention, and FIG. 5 shows a conventional load indicator. 9... Winch drum, 10... Wire rope, 12... Load indicator, 15... Hydraulic motor,
16... Winding layer number indicator (rated load indicator).

Claims (1)

[Scope of utility model registration request] Guide the wire rope wound around the winch drum at the base end of the crane boom to the boom tip side, suspend the hook with this wire rope from the boom tip side, and connect the wire rope wound around the winch drum. This is a hydraulic crane configured to raise and lower a load by lifting and lowering a hook, and detects the operating pressure of the hydraulic motor that drives the winch drum during hoisting, and uses this operating pressure as the crane. In a load indicating device for a hydraulic crane having a load indicator that indicates a load as a lifting load of The number of winding layers of the hook is fixed, the height of the hook is fixed, the boom length is determined as a plurality of predetermined fixed boom lengths, and only the boom angle is determined as a variable parameter. A winding layer number indicator is provided to indicate the number of winding layers for each boom length predetermined by a guideline, and a load scale for each winding layer number is displayed on the scale plate of the load indicator. A load indicating device for hydraulic cranes that reads the crane's lifting load according to the number of winding layers.