JP2769085B2 - Jib elevating rope life determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane, and more particularly, to a jib elevating rope life determining device.

[0002]

2. Description of the Related Art Jib elevating ropes mounted on cranes need to be replaced because they become fatigued during repeated use. Since the degree of wear of the jib elevating rope varies depending on the use condition of the crane, the replacement time cannot be set at all. Therefore, the jib elevating rope is inspected to determine the replacement time. As an inspection method, a method using magnetic flaw detection is known.

[0003]

The inspection method using magnetic flaw detection described above is expensive because the equipment is expensive, so mounting it for each crane requires high costs. In addition, inspection method is difficult,
Skilled techniques are required to detect abnormalities with high accuracy, and are not suitable for use by ordinary crane operators.

[0004] On the other hand, it is conceivable that the jib elevating rope is replaced periodically. However, in a crane in which the life of the jib elevating rope varies greatly depending on the use condition of the crane and the work content changes daily, the jib elevating rope is changed before the replacement time. There is a danger that the tire will reach its limit and break, and in that case, there is a danger that the jib will fall and cause a major accident. Therefore, there is a technical problem to be solved in order to set a safe and economical replacement time and to prevent a large accident from occurring, and the present invention aims to solve this problem. .

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object, and comprises a jib elevating angle detector, a jib elevating rope tension detector, and a jib elevating lever operation detector. sets a plurality of virtual points at equal intervals on the jib derricking rope, previously obtained, respectively Sea every point jib derricking angle at which each point passes sheaves
The jib elevation angle and the number of sheave passages when passing through the jib are stored in the memory, and when the jib elevation lever is operated, the jib elevation rope tension and the jib elevation angle are read every fixed sampling time, and the Calculate the safety factor for the rope breaking tension from the jib elevating rope tension to obtain the life conversion factor for the legal safety factor, compare the jib elevating angle at that time with the stored jib elevating angle for each point, When the angles match, the life conversion coefficient is added to the stored number of sheave passes to correct the number of sheave passes, the corrected number of sheave passes is again stored in memory, and then the stored sheave pass is stored. A means for finding the maximum value of the number of times and comparing it with the standard number of times of bending fatigue to determine whether the maximum value of the number of times of sheave passage has reached the number of times of standard bending fatigue. There is provided a life determining apparatus of digits jib derricking rope.

[0006]

[Action] The jib elevation angle when the virtual point set on the jib elevation rope passes through the sheave is determined in advance, and the jib elevation angle and the number of sheave passages when passing the sheave for each point are stored in memory. deep. When the jib is lifted, the jib lifting rope tension and the jib lifting angle are read at a constant sampling time. The safety factor for the rope breaking tension is calculated from the jib elevating rope tension at that time, and the life conversion factor for the legal safety factor is calculated from the relationship between the safety factor and the life factor obtained in advance from experimental data.

The jib elevation angle at that time is compared with the jib elevation angle for each point stored in the memory. When both angles match, the number of sheave passes at that point is called, and a life conversion coefficient is added to this to correct the number of sheave passes. The corrected number of sheave passes is stored again in the memory. Next, the maximum value of the number of sheave passes stored in the memory is searched for and compared with a known standard number of times of bending fatigue at the legal safety factor. When the maximum value of the number of sheave passes reaches the standard number of times of bending fatigue, it is determined that the jib elevating rope has reached the end of its life.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a crawler crane, in which a jib 12 is attached to the front of a body 11 so as to be able to move up and down, one end of a support rope 13 is locked to a tip 12a of the jib, and Lock to bridle 14. A plurality of sheaves are pivotally connected to the bail 16 and the bridle 14 attached to the upper end of the mast 15 as described later, and a jib elevating rope 17 is wound between the sheaves. Frame 19
And the other end is wound around the jib raising drum 20. A sheave 21 is pivotally mounted on the tip 12a of the jib, and a hook 23 is hung around a front rope 22. Further, the front rope 22 is wound around the front drum 24 mounted on the front part of the body 11.

By rotating the jib raising drum 20 to raise and lower the jib raising rope 17, the jib 1
2 can be raised and lowered and the elevation angle can be changed.
By rotating the front rope 22 by rotating the hook 23, the hook 23 can move up and down to lift the load. An operation sensor 25 is attached to a jib elevating lever (not shown) provided in the driver's seat to detect a jib elevating operation signal, and an angle sensor 2 is attached to a mounting portion of the jib 12.
6 is mounted to detect the jib elevation angle signal.

FIG. 2 shows an example of a method of winding the jib elevating rope 17. The jib elevating rope 17, one end of which is fixed to a frame 19 via a load cell 18, is pivotally attached to the upper end of a mast 15. Wound around a second sheave 28 pivoted to bridle 14 through sheave 27
It is wrapped around the third sheave 29 pivotally attached to 6. Less than,
Fourth sheave 30, fifth sheave 31, sixth sheave 32, seventh sheave 33, eighth sheave 34, ninth sheave 35, tenth sheave 36 pivotally attached to bridle 14 or bail 16. , The jib raising rope 17 is wound in the order of the eleventh sheave 37, and the other end is the jib raising drum 20.
Wound around. In this embodiment, the number of sheaves is 10, and the bridle 14 and the bail 1 are only 1/10 of the length of the jib raising rope 17 wound up and down on the jib raising drum 20.
6 changes.

FIG. 3 is a block diagram showing the construction of a jib elevating rope life judging apparatus. The jib elevating angle detector 26 is a jib elevating angle detector. The load cell 18 is a jib elevating rope tension detector. A rotation sensor 25 as a detector is provided, and a signal detected by each detector is input to the control unit. Next, the jib raising rope 17
Will be described. Jib elevating rope 17
The life of the wire is mainly determined by the fatigue breaking of the wire due to repeated bending, and the degree of fatigue is determined by the number of sheave passes and the rope tension at that time. The amount of rope movement required for any one point of the jib elevating rope 17 to pass once through the sheave is determined by the distance between the bridle 14 and the bail 16,
This distance varies with the jib elevation angle.

FIG. 4 shows an arbitrary point A on the jib elevating rope 17.
7 is a graph showing a place where passes through a first sheave 27 to an eleventh sheave 37. For example, when the point A is set on L1 as shown in FIG.
It passes through three sheaves of the seventh, tenth sheave 36 and ninth sheave 35, and the jib elevation angles when passing through each sheave can be specified as α _a1 , α _a2 and α _a3 , respectively. . Here, when a plurality of virtual points 1 to n are set at equal intervals on the jib raising rope 17, the jib raising angle and the number of sheave passing times when the points pass through each sheave are shown in Table 1.

[0013]

[Table 1]

On the other hand, the rope bending fatigue life also changes depending on the rope tension. FIG. 5 shows a flowchart. When the jib elevating lever is operated, it can be understood that the signal of the operation sensor 25 has operated the jib elevating operation. When accordingly reads the tension signal F _i of the load cell 18 to the control unit for each predetermined sampling time. From the jib elevating rope tension F _i at that time, the rope breaking tension F _L known in advance is used.
Is determined.

[0015]

(Equation 1)

Assuming that the life at a statutory safety factor 5 defined by the safety rules for cranes and the like is 1, the life factor when using at another safety factor is obtained in advance by experimental data, and is shown in FIG. As shown in the graph, it is represented by a life conversion coefficient N with respect to the legal safety factor. Here, the life conversion coefficient is a value obtained by replacing the fatigue life at a safety factor of 5, which is the legal safety factor, with 1, assuming that the fatigue experienced when passing through the sheave once is different depending on the safety factor. is there. For example, the life conversion coefficient N for the safety factor f is 0.7
If the sheave passes through the sheave 100 times at the safety factor f, it corresponds to 100 × N = 70 at the safety factor 5, that is, 70 passes through the sheave. The data of this graph is stored in the memory in advance.

Further, it reads the angle signal θ with reading of the tension signal F _i, jib derricking angle alpha ₁₁ for each point stored in the memory, alpha _21, alpha _22, compared with ...... α _nm. When both angles match, invoking the sieve pass count M _i of the point, to which is added the life conversion factor N for correcting the sieve pass count M _i. For example,
If a match with a jib derricking angle alpha _ij to read angle signal θ passes through the sieve, which is stored in the memory, the correction and M _i + N by adding the life conversion factor N the sheave number of passes M _i stored in the memory I do. Then, again stored in the memory as M _i the corrected sieve pass count.

Next, the maximum value of the number of sheave passages M _{1 to} M _n stored in the memory is found and defined as M _MAX, and the maximum number of times of use due to the bending fatigue of the rope when used at the legal safety factor is defined as the standard bending fatigue. Let L be the number of times. The control unit determines whether compares the maximum value M _MAX and the standard bending fatigue number L of sieve pass count, the maximum value M _MAX sieve pass count reaches a standard bending fatigue number L. Maximum number of sheave passes M _MAX
Is less than the standard number of times of bending fatigue L, it is regarded as the life range of the jib elevating rope 17 and is used continuously. Then, when the maximum value M _{MAX of the} number of sheave passes reaches the standard number of times of bending fatigue L, the control unit determines that the jib elevating rope 17 has reached the end of its life and issues an alarm.

The operator can confirm from this alarm that the jib elevating rope 17 has become fatigued and replace it with a new jib elevating rope. That is, since the life of the jib elevating rope is automatically determined, the operator does not mistakenly judge the rope replacement time, and a large accident due to the breakage of the jib elevating rope can be prevented. In addition, the present invention can make various modifications without departing from the spirit of the present invention, and
Naturally, the invention extends to such modifications.

[0020]

As described in detail in the above embodiment, the present invention does not require the operator to inspect the jib elevating rope.
Since the life of the jib raising rope is automatically determined, the burden on the operator for fatigue of the jib raising rope is significantly reduced. Therefore, it is possible to prevent the jib elevating rope from being broken when the jib elevating rope replacement time is delayed, and to prevent a large accident from occurring, which can contribute to improvement of safety. It is an invention that has various effects such as eliminating wasteful disposal and contributing to improved economic efficiency.

[Brief description of the drawings]

FIG. 1 is a side view of a crawler crane.

FIG. 2 is an explanatory view showing a method of winding a jib elevating rope.

FIG. 3 is a block diagram showing a configuration of a jib elevating rope life determining device.

FIG. 4 is a graph showing where arbitrary points on a jib elevating rope pass through each sheave.

FIG. 5 is a flowchart until a maximum value of the number of sheave passes is determined and an alarm is issued.

FIG. 6 is a graph showing a life conversion factor with respect to a legal safety factor.

[Explanation of symbols]

 17 Jib elevating rope 18 Load cell 25 Operation sensor 26 Angle sensor

Continuation of front page (56) References JP-A-4-350097 (JP, A) JP-A-2-81894 (JP, A) JP-A-5-39187 (JP, A) JP-A-62-17638 (JP) JP-A-62-132144 (JP, A) JP-A-5-97397 (JP, A) JP-A-3-44191 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB Name) B66C 23/00-23/94 B66C 15/02 B66D 1/54

Claims (1)

(57) [Claims] A jib elevating angle detector, a jib elevating rope tension detector, and a jib elevating lever operation detector are provided, and a plurality of virtual points are set at equal intervals on the jib elevating rope, and each point is a sheave. When the jib elevation angle is determined beforehand when passing through the sheave, and when passing through the sheave for each point
The jib elevating angle and the number of sheave passes are stored in memory, and when the jib elevating lever is operated, the jib elevating rope tension and the jib elevating angle are read at a fixed sampling time, and the jib elevating rope tension at that time is read. When the safety factor for the rope breaking tension is calculated to obtain the life conversion factor for the legal safety factor, the jib elevation angle at that time is compared with the stored jib elevation angle for each point, and when both angles match. The life conversion coefficient is added to the stored number of sheave passes to correct the number of sheave passes, the corrected number of sheave passes is again stored in memory, and then the maximum value of the stored number of sheave passes is calculated. A means is provided for determining whether the maximum value of the number of sheave passes has reached the standard number of times of bending fatigue by comparing with the number of times of standard bending fatigue. Life determining apparatus of the jib elevation rope.