GB2189456A

GB2189456A - Device for protecting hoisting mechanisms against overloads and tipping

Info

Publication number: GB2189456A
Application number: GB8610049A
Authority: GB
Inventors: Eduard Nikolaevich Kuzin; Evgeny Jurievich Malinovsky; Vilory Kuzmich Petrov; Dmitry Matveevich Mash; Valery Adolfovich Sushinsky; Vladimir Alexandrovich Lebedev; Leonid Vladimirovich Zaitsev; Boris Georgievich Vasin; Jury Fedorovich Timin; Nikolai Ivanovich Shindin; Jury Petrovich Slepov; Jury Alexandrovich Berezkin; Vladimir Viktorovich Lupandin; Mikhail Sergeevich Antonov
Original assignee: MO N PROIZV OB STR DOROZH MASH
Current assignee: MO N PROIZV OB STR DOROZH MASH
Priority date: 1986-04-24
Filing date: 1986-04-24
Publication date: 1987-10-28
Also published as: FR2599015B1; FR2599015A1; GB2189456B; DE3613870A1; GB8610049D0

Abstract

A device for protecting hoisting mechanisms against overloads and tipping comprises a hoisting mechanism overload estimation unit (1) and a hoisting mechanism factual stability monitoring unit (2), with respective input (3,4) of the hoisting mechanism protection pattern selection unit (5) being connected to each of said units (1, 2). A hoist mechanism cut-out unit (6) is connected to said hoisting mechanism protection pattern selection unit (5). <IMAGE>

Description

SPECIFICATION Device for protecting hoisting mechanisms against overloads and tipping The invention relates to lifting-and-conveying machines and, more particularly, to devices for protecting hoisting mechanisms against overloads and tipping.

The herein disclosed invention may be used to protect boom self-propelled hydraulic cranes with an air-operated wheel drive against overloads and tipping.

Known in the present state of the art is a device for protecting hoisting mechanisms against overloads and tipping, comprising a hoisting mechanism overload estimation unit and a hoisting mechanism cut-out unit, electrically connected to each other.

However, the given device is adjusted to a rated supporting contour of the hoisting mechanism, e.g., a crane (most suitable from the standpoint of its configuration), and in no way respondsto unfavourablevariations ofthis contour, e.g., as the ground subsides underneath one of the supports and a quadrangular supporting contour (rated) turns into a triangular (factual) one, thus diminishing the accuracy ofthe device which, in turn, impairs the reliability of the hoisting mechanism protection, i.e., may lead to a breakdown.

Besides, in the given device the overload estimation unit of the hoisting mechanism programmes a load characteristic corresponding to the least (for the rated supporting contour) load capacity (allowing for the impact ofwind, a platform slope angle, the strength conditions of individual units, etc.), which in most cases results in the underutilization of the hoisting mechanism capacity.

It is an object of the present invention to increase the accuracy of the device.

It is another object of the invention to improve reliability of the hoisting mechanism protection system.

It is still another object of the invention to extend functional possibilities of the device.

The object of the present invention is accomplished by the use of the device for protecting hoisting mechanisms against overloads and tipping, comprising the hoisting mechanism overload estimation unit and the hoisting mechanism cut-out unit, electrically connected to each other, which according to the invention, additionally incorporates a hoisting mechanism factual stability monitoring unit and a hoisting mechanism protection pattern selection unit, connected in series to each other, the other input of the said selection unit being electrically connected to the hoisting mechanism overload estimation unit, and the output - to the hoisting mechanism cut-out unit, It is expedientthatin the device for protecting hoisting mechanism against overloads and tipping an OR logic be used as the hoisting mechanism protection pattern selection unit.

It is advisable that the device for protecting hoisting mechanisms against overload and tipping be provided with a basic and an additional AND logics, some inputs ofwhich are connected, respectively, to the hoisting mechanism overload estimation unit and to the hoisting mechanism factual stability monitoring unit, while the outputs to the OR logic, with an inverter whose output is connected to the other input of the additional AND logic, and with a hoisting mechanism boom angle data transmitter whose output is connected to the inverter input and the other input pf the basic AND logic.

The present invention monitors the condition of the crane supporting contour, which improves the device accuracy and dependability ofthe hoisting mechanism protection system.

Besides, the invention makes it possible to alternately estimate an overload or monitor the factual stability of the hoisting mechanism, thus extending functional possibilities of the device.

Other objects and advantages of the present invention will be disclosed upon considering the description of an exemplary embodiment thereof, with references to the accompanying drawings in which: Figure lisa block-diagram of the device for protecting hoisting mechanisms against overloads and tipping, according to the invention; Figure2 is a block-diagram of the device for protecting hoisting mechanisms against overloads and tipping according to Figure 1 with AND logics, according to the invention; Figure 3 is a diagram of operation of the device for protecting hoisting mechanisms against overloads and tipping for cranes with a quadrangular supporting contouraccordingto Figures 1 and 2, according to the invention;; Figure4is a diagram of operation of the device for protecting hoisting mechanisms against overloads and tipping for cranes with a triangular supporting contour, according to Figures 1 and 2, according to the invention.

The device for protecting hoisting mechanisms against overloads and tipping comprises a hoisting mechanism overload estimation unit 1 (Figure 1) and a hoisting mechanism factual stability monitoring unit 2, with inputs 3 and 4 of the hoisting mechanism protection pattern selection unit 5 being respectively connected to the outputs of both units 1, 2. An input7 of the hoisting mechanism cut-out unit 6 is connected to the output of the unit 5.

According to another embodiment variant the device for protecting hoisting mechanisms against overloads and tipping additionally comprises a basic 8 (Figure 2) and an additional 9 AND logics whose inputs 10 and 11 are respectively connected to the units 1 and 2. An output 15 of a hoisting mechanism boom angle datatransmitter 14and an inverter 16 are respectively connected to other inputs 12 and 13 of the AND logics 8 and 9, respectively. An input 17 of the inverter 16 is connected to the output 15 of the transmitter 14. The outputs ofthe AND logics Band 9 are respectively connected to the inputs 3,4 ofthe unit 5.

Figure 3 illustrates a diagram of operation ofthe device for protecting hoisting mechanisms against overloads and tipping for cranes with a quadrangular contour, the load on the hook being unchanged, where a quadrangular supporting contour 18 is a prescribed load characteristic and a contour 19 is the factual state ofthe crane stability.

Figure 4 shows a diagram of operation ofthe device for protecting hoisting mechanisms against overloads and tipping for cranes with a triangular supporting contour, the load on the hook being unchanged, where a triangular supporting contour 20 is a prescribed load characteristic intersecting the contour 19 in points 21 and 22 intotwo curves 23 and 24.

The device for protecting hoisting mechanisms against overloads and tipping, in the case a boom self-propelled hydraulic crane with an air-operated wheel drive is protected, operates as follows.

Acrane overload estimation unit 1 (Figure 1) is connected simultaneously with a crane factual stability monitoring unit 2. The unit 1 protects the crane at a distance determined by contours 18 (Figure 3) or 20 (Figure 4), while the unit 2 monitors the crane factual stability, i.e., effects preliminary protection at distances determined by the contour 19 (Figures 3,4).

From the units 1 and 2 signals come to the inputs 3, 4 of the OR logic 5, respectively. The OR logic 5 creates a control signal which enters the input7 of of the crane cut-out unit 6.

Thus, the device operates along the contour 19 (Figure 3) and the contourdefined buy a curve 23 lFigure4) ofthe contour 19 and a straightline between the points 21 and 22 of the contour 20.

In some cases, it is reasonable that the signals from the units 1 and 2 should come alternately.

At large angle of slope ofthe boom to the horizon when the crane safe position is determined by its strength, a signal comes from the unit 1 (Figure 2).

Given small angles of slope ofthe boomtothe horizon,when the crane safe position is determined by its stability, a signal comes from the unit 2.

Thus, signals are derived alternately from the units 1 and 2.

From the unit 1 a signal enters the input 10 ofthe basic AND logic 8. From the output 15 ofthe crane boom angle data transmitter 14 a signal comes to the other input 12 of the AND logic 8. From the latterthe signal enters the input 3 ofthe OR logic 5. The OR logic creates a signal at the input7 ofthe unit6to operatethe latter. Simultaneously, from the output 15 of the transmitter 14 a signal comes to the input 17 ofthe inverter 16, and therefrom,to the input 13 of the additional AND logic 9 and 'inhibits' the passage ofthe signal from the unit 2 via the AND logic 9 to the input 4 of the OR logic 5.

Atsmall angles of slope of the boom a signal is not fed from the transmitter 14, thereby the passage of the signal from the unit 1 via the AND logic 8 is suppressed. Atthe same time, the inverter 16 creates an 'enabling' signal atthe input 13 of the AND logic 9 for the signal to pass from the unit 2 via the AND logic9 to the input4 of the OR logic 5. The OR logic5 creates a signal atthe input7 of the unit 6 to operate the latter.

The present invention makes it possible to monitor a stable position ofthe crane to make its protection more reliable.

Claims

1. Adeviceforprotecting hoisting mechanisms against overloads and tipping, comprising a hoisting mechanism protection pattern selection unit, with a hoisting mechanism overload estimation unit and a hoisting mechanism factual stability monitoring unit being respectively connected to each input of said protection pattern selection unit, and a hoisting mechanism cut-out unit whose input is connected to the hoisting mechanism protection pattern selection unit.

2. A device according to claim 1, wherein an OR logic is used as the hoisting mechanism protection pattern selection unit.

3. Adeviceaccordingto claim 2,which comprises a basic and an additional AND logics whose inputs are connected respectively to the hoisting mechanism overload estimation unitandto the hoisting mechanism factual stability monitoring unit, and the outputs -to the OR logic, an inverter whose output is connected to the other input ofthe additional AND logic, and a hoisting mechanism boom angle data transmitter whose output is connected to the input ofthe inverter and to the other inputofthe basicANDlogic.

4. Adeviceforprotecting hoistingmechanisms which is embodied as described hereinabove with references to the accompanying drawings.