JPH11322276A - Safety device for crane with luffing jib - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent danger due to an erroneous operation when a crane is operated from a crane working position to a crane assembly/disassembly position or operated reversely so as to accomplish improvement in safety and operability, prevention of breakage, and reduction in labor of an operator in an operation time. SOLUTION: A crane with a luffing jib is provided with a main jib having a jib derricking rope 13, which is arranged between the tip parts of a front post 4 installed to the base part of a luffing jib 2 via its end and a rear post 5 installed to the top part of the main jib via its end, and a luffing jib provided at the tip of the main jib. In the crane with a luffing jib, a lower limit value is detected within a safe range of a tangent distance 1 between the jib derricking rope 13 and the luffing jib installed end part 2a side and the front post installed end part 4a, and this detection is informed to an operator as a jib derricking rope unwinding limit. A safe range detector is constructed of a detection rod 20 arranged on a telescopic device 17, which is arranged between the front and rear posts 4, 5 and extended/shrunk synchronously with the front post 4, and a lower limit detector 18 and an upper limit detector 19, each of which is brought into contact with the detection rod 20 so as to generate a signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for changing a working posture of a crane with a luffing jib from a working posture to a disassembled posture or vice versa.

[0002]

2. Description of the Related Art FIG. 3 is an overall side view showing a working posture of a known crane with a roughing jib. A is a crane-type crane body (of course, a truck type or a stationary type). 1 is a main jib, 2 is a roughing jib, and 3 is a lifting hook. Reference numeral 4 denotes a front post having a base at the base of the luffing jib 2, and reference numeral 5 denotes a rear post having a base at the top of the main jib 1. 6 is a main boom undulation winch,
7 is a luffing jib undulation winch. Reference numeral 8 denotes a main boom hoisting rope, which is connected to a main boom support pendant loop 9. A hook winding winch 10 raises and lowers the hook 3 through a rope 11. Reference numeral 12 denotes a jib hoisting rope whose upper end is fixed to the front end of the rear post 5. 13 is a jib hoisting rope and 14 is a support pendant.

A procedure for changing the crane from the working posture to the disassembly posture will be described with reference to FIGS. The reverse operation is performed from the assembly posture to the work posture. (1) The luffing jib hoisting winch 7 is operated from the working state of FIG. 3 to loosen the jib hoisting rope 13 to increase the distance between the top of the front post 4 and the top of the rear post 5, and the luffing jib 2 is tilted to the left in the drawing. . When the relative angle of the luffing jib 2 with respect to the main boom reaches the state shown in FIG. 4, the luffing jib hoisting winch 7 is stopped (FIG. 4).

(2) Next, the main boom hoisting winch 6 is unwound, the main jib 1 is lowered, and the tip of the luffing jib 2 is moved to the ground via a roller 3a or the like (FIGS. 5 and 6). (3) Further, the main jib 1 is tilted down, and the jib hoisting rope 13 is gradually wound up while observing the inclination of the jib hoisting rope 13 and the front post 4, and the state shown in FIG. 6 (assembly disassembly posture) is obtained. .

[0005] These operations are usually specified in the instruction manual. The operator operates the crane according to the above-mentioned procedures (1), (2) and (3). In this case, if the operator operates correctly, the posture can be changed without any problem. Sometimes. In particular, erroneous operation of the jib hoisting rope 13 and the luffing jib hoisting winch 7 is likely to lead to damage of the related attachment.

An example of damage due to such an erroneous operation will be described below with reference to the drawings. (1) FIG. 7 shows a state in which the front post 4 and the luffing jib 2 have been moved forward due to excessive unwinding of the jib hoisting rope 13. When the jib hoisting rope 13 is further unwound in the state of FIG. 5, the front post 4 and the luffing jib 2 tilt forward, the tangential distance between the jib hoisting rope 13 and the jib foot 2a becomes shorter, and the jib The up-and-down rope 13 cannot support the jib attachment and moves forward. In this case, even if the jib hoisting rope 13 is wound up, it is impossible to return to the original normal state.

(2) FIG. 8 shows a state where the jib hoisting rope 13 has been unwound too much and the front post 4 has been moved forward. During the transition from the position shown in FIG. 5 to the position shown in FIG. 6, the operation to wind up (or wind up) the jib hoisting rope 13 is erroneously unwound, and the jib hoisting rope 13 and the front post 4 are unwound. Becomes short, and the jib hoisting rope 13 cannot support the front post 4 and moves forward. In this case as well, it cannot be restarted as in the state of FIG.

[0008]

As described above, in the crane with the luffing jib 2, the operation from the crane working position to the crane assembling / disassembling position or vice versa. At times, the attachment may be in a dangerous state due to an erroneous operation or the like. However, the present invention is configured to prevent such a risk beforehand, thereby improving the safety of the crane, preventing damage, and improving operability. It is an object of the present invention to improve and reduce the burden on the operator when operating.

[0009]

SUMMARY OF THE INVENTION A front post 4 attached to the base of a luffing jib 2, a rear post 5 attached to the top of a main jib 1, and a jib undulation provided between the tops of both posts 4 and 5. In a crane with a luffing jib provided with a main jib 1 having a rope 13 and a luffing jib 2 at the tip thereof, the lump between the jib undulation 13 and the luffing jib 2 and the limping part 4a of the front post 4 are provided.
The length detection device 1 determines the lower limit value within a safe range of the tangent distance 1 between
6 and the jib undulation is applied to the operator.
And the length detection device 16 for the safety range of the tangential distance 1 is synchronized with the front post 4 provided between the front post 4 and the rear post 5. It is characterized by comprising a telescopic device 17 that expands and contracts, a detection rod 20 provided on the telescopic device 17, and a lower limit detector 18 and an upper limit detector 19 that contact and emit a signal. A safe state can be automatically secured in combination with the operation stop device of the jib hoisting winch 7.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the prior art described above, the forward tilt angle of the front post 4, the jib hoisting rope 13, the luffing jib 2 and each foot (base portion) 2a, 4a of the front post 4 have been described. The limit of the tangential distance 1 (FIG. 9) was dependent on the attention of the operator. The present invention detects the lower limit of the safe range of the tangential distance 1 between the jib hoisting rope 13 and the jib foot 2a of the luffing jib 2 and between the jib foot 2a and the front post foot 4a. Undulating
This is to notify that the unwinding limit of the loop 13 is reached.

Further, by installing an automatic stopping device for stopping the unwinding and unwinding of the jib hoisting winch 7, safety can be further improved. Hereinafter, embodiments will be described. FIG. 1A shows a length detecting device according to the present invention, and FIG. 1B is an overall view of a crane device. In FIG. 1, a length detecting device 16 is provided between lugs 15a and 15b provided near the base portions 4a and 5a of the front post 4 and the rear post 5.
Is provided. The detection device 16 includes a telescopic device 17 that telescopically expands and contracts, and a lower limit detector 18 and an upper limit detector 19 provided on the telescopic device 17. Reference numeral 20 denotes a detection rod whose tip is the sensor 18a of the lower limit detector 18.
Alternatively, it comes into contact with the sensor 19a of the upper limit detector 19 to emit a signal.

In FIG. 1 (b), there is a correlation between the tangential distance 1 and the undulating rope length lL. Also, undulating rope length lL
There is also a correlation with the length ls of the telescopic device of the length detector. Therefore, when the tangential distance is l, the length of the detector is ls
Is the present invention.

In FIG. 1, when the jib hoisting rope 13 is unwound, the tangential distance 1 gradually decreases. A limit l is defined, and a limit length ls of the jib undulation rope at that time is defined (FIG. 1A). When the jib hoisting rope 13 is unwound by the operation of the operator and reaches the specified limit length ls, the lower limit detector 18 detects this and sends a signal to the controller.
When the jib hoisting rope 13 is wound up too much, ls becomes short, and when it reaches the limit, the lower limit detector 18 is operated.

(Operation) A length detecting device 16 which expands and contracts in synchronization with the movement of the front post is provided. When the front post 4 tilts forward, the telescopic device of the length detecting device 16 is extended, and a predetermined length is set. At this point, the upper and lower detectors detect this and emit a signal. Conversely, if the jib hoisting rope is excessively wound, the front post 4 and the rear post 5 may collide with each other. Therefore, even at the limit (the upper limit of the front post), the upper limit detector operates and outputs a signal.

FIG. 2 is a system block diagram. In the present invention, the signals generated by the lower limit detector 18 and the upper limit detector 19 are input to the front post angle management control unit 21 and
An alarm is issued to the driver's cab 23 via the safety management control unit 22. Reference numeral 24 denotes a switch for stopping and unwinding the unwinding and operation of the jib hoisting winch 7, but it is of course possible to use only the alarm device.

[0016]

According to the first aspect, the telescopic device 17 expands and contracts in synchronism with the movement of the front post, and the upper or lower limit detector is operated by the detection rod 20 to generate a signal.
When the operation is changed from the crane working posture to the crane assembling / disassembling posture or vice versa, it is possible to prevent the attachment from becoming dangerous due to erroneous operation. It has become possible. Thus,
Improve the safety of the crane, prevent breakage, improve operability,
And the purpose of reducing the burden on the operator when operating can be sufficiently achieved. According to the second aspect of the present invention, a safer device which is safer and does not impose a burden on the operator can be obtained by combining with the automatic operation stop of the winch.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of the present invention, wherein FIG.
Fig. 1 is an overall view of a crane provided with this.

FIG. 2 is a system block diagram of the present invention.

FIG. 3 is an overall view of the working posture of a crane with a known wing jib.

FIG. 4 is a diagram showing a state during transition to an assembly disassembly posture.

FIG. 5 is a diagram showing a state in which the transition is further advanced than in FIG. 6;

FIG. 6 is a view showing an assembling / disassembling posture of the crane.

FIG. 7 is a diagram illustrating an example of a result of an erroneous operation.

FIG. 8 is a diagram showing an example of an erroneous operation during the transition from FIG. 7 to FIG. 8;

9A and 9B are diagrams showing a tangential distance 1 between a jib hoisting rope and each foot (base portion), wherein FIG. 9A shows the state shown in FIG. 6 and FIG.

[Explanation of symbols]

A (Crane) Crawler-type main body 1 Main jib 2 Luffing jib 3 Lifting hook 4 Front post 5 Rear post 6 (Main boom) Up / down winch 7 Jib up / down winch 8 Main boom up / down rope 9 Support pendant loop 10 Hook hoisting winch 11 Loop 12 Jib hoisting rope 13 Jib hoisting rope 14 Support pendant 15a, 15b Lug 16 Length detector 17 Telescopic device 18 Lower limit detector 18a, 19a Sensor 19 Upper limit detector 20 Detection rod 21 Front post angle control unit 22 Crane safety management control unit 23 Operator cab 24 Winch unwinding stop / stop switch

Claims (2)

[Claims] 1. A front post (4) attached to the base of a luffing jib (2), a rear post (5) attached to the top of a main jib (1) and the top of both posts (4 and 5). In a crane with a luffing jib provided with a luffing jib (2) at the end thereof and a main jib (1) having a jib luffing rope (13) provided therebetween, the luffing jib (13) and luffing jib (2) are provided. (2a)
Tangential distance l between the base and the base (4a) of the front post (4)
The lower limit value is detected by the length detecting device (16) within the safe range of the above, so that the operator is notified that it is the unwinding limit of the jib hoisting rope (13). A front post provided between the front post (4) and the rear post (5) by a length detecting device (16) of a safe range having a tangential distance 1
Telescopic device (17) that expands and contracts in synchronism with (4), and telescopic device (17)
A safety device for a crane with a luffing jib, comprising a detection rod (20) provided above, and a lower limit detector (18) and an upper limit detector (19) that emit a signal in contact with the detection rod (20). 2. A safety device for a crane with a luffing jib according to claim 1, wherein a safe state can be automatically secured in combination with a device for stopping operation of the jib hoisting winch (7).