RU54366U1 - LOAD LOAD LIMITER - Google Patents

Abstract

The utility model relates to the field of hoisting and transport engineering and can be used in safety devices to limit the load. The load limiter of the hoisting machine contains a digital computing unit, peripheral parameter recording devices and an executive unit connected to the outputs of the digital computing unit, an alarm unit, and a visual indication unit. Peripheral devices for recording parameters include sensors for determining the load on the load gripping body, sensors for determining the force in the cargo cable, and sensors for the direction of rotation of the drum of the cargo winch connected to the information inputs of a digital computing unit. To the additional input of the digital computing unit is connected the loss factor adjuster in the cargo block block.

Description

The utility model relates to hoisting and transport machinery, and in particular to load limiting devices of hoisting machines.

Known load limiter of a crane [RF Patent RU 7097 U1 6 V 66 C 23/90, 1998] and a safety system of a crane [RF Patent RU 38747 U1 7 V 66 C 23/90, 2004] (prototype), including analog parameters crane operation, sensors of discrete parameters and signals, a digital computing unit, an executive unit, an alarm unit and a visual indication unit. In such devices, it is proposed to use discrete sensors such as proximity inductive switches to determine the multiparticle of the cargo channel pulley.

In hoisting machines, in which the branches of the cargo cable change direction relative to the metal structure, for example, in jib cranes, the installation of such sensors, which ensures reliable operation, is very difficult. Therefore, discrete sensors are practically not used to determine the chain hoist ratio (reserve), and the reserve is set manually by the crane driver using a switch installed either in the safety device or in the crane dashboard [Crane load limiters (load limiters) ОНК-140-05, ОНК -140-05M, ONK-140-08, ONK-140-08M, ONK-140-27, ONK-140-27M. Manual. LGFI. 408844.009-05 RE, OAO APZ, 1997], [Crane load limiters (load limiters) ONK-140. Manual. LGFI. 408844.009-28 RE, JSC "APZ", 2002]. This solution does not guarantee the protection of the cargo rope from overload (when determining the load on the hook using force or pressure sensors installed in the boom lifting mechanism), and does not allow the crane to use its full capacity (when determining the load on the hook using the force sensor in the cargo cable) because the driver may make a mistake or forget to set the switch to the desired position after overloading the cargo rope.

The main purpose of the proposed utility model of the load limiter of the load lifting machine is to increase the safety of the load lifting machine and increase the efficiency of its use by reliably determining both the load on the load gripping body (hook) and the load in the cargo rope and the actual multiplicity of the chain hoist of the cargo rope.

This goal is achieved due to the fact that the load limiter of the lifting machine, including a digital computing unit, to the outputs

which is connected to a visual display unit, an alarm unit, an executive unit, and outputs of peripheral devices for registering crane parameters are connected to the information input. The structure of the sensors of the analog parameters of the work of the lifting machine includes both sensor (s) for determining the load on the load gripping body (hook) and sensor (s) for determining the force in the cargo rope, and a loss factor adjuster in the cargo block block is connected to the digital computing unit . The sensors of discrete signals include sensors for the direction of rotation of the cargo winch. Based on the values of the signals of the load sensors on the load gripping body and in the cargo rope, taking into account the data on the direction of rotation and the magnitude of the losses in the pulley block, the effective values of the load on the hook, in the rope and the multiplicity of storage of the cargo rope are calculated in a digital computing unit. If the load on the hook exceeds the rated value of the carrying capacity at this departure, the digital computing unit generates a signal to the executive unit to turn off the load lifting mechanisms and increase the outreach. If the load in the rope exceeds the permissible value without exceeding the load capacity of the machine, the digital computing unit generates a signal to the executive unit only to turn off the hook lifting mechanism. At the same time, an alarm signal is generated by a digital computing unit and information on the limitations achieved and the calculated value of the multiplicity of the hoisting rope of the cargo rope are displayed on the visual indication unit.

The block diagram of the load limiter of the lifting machine is presented in figure 1.

The load limiter of the load-lifting machine contains a sensor (s) 1 of the analog parameters of the crane to determine the load on the load-gripping body, a sensor (s) 2 forces in the cargo cable, sensors 3 discrete signals about the direction of rotation of the cargo winch, a digital computing unit 4, a loss factor adjuster 5 in the block of the pulley block, the executive unit 6, the alarm unit 7 and the visual indication unit 8. The outputs of the sensors 1, 2 and 3 are connected to the inputs of the digital computing unit 4 either directly (when using sensors with a digital output signal), or, if necessary, through an analog-to-digital converter. Another input of the digital computing unit 4 is connected to the output of the setter 5 of the loss coefficient in the block tackle. The outputs of the digital computing unit 4 are connected to the executive unit 6, the alarm unit 7 and the visual indication unit 8.

The sensor (s) 1 for determining the load on the load-gripping body are either hook scales, for example, electronic crane scales with a radio channel for directly measuring the load on the hook, or a set of sensors for calculating the load on the hook by the magnitude of the force in the boom lifting mechanism, including a sensor ( i) force (or pressure), boom angle sensor and boom length sensor (for cranes with telescopic booms).

The force sensor (s) 2 in the cargo cable are installed either in the stationary or on the movable branch of the cargo cable, or in the supports of the cargo winch.

As sensors 1, 2 of the analog parameters of the load lifting machine, sensors 3 of digital signals, digital computing unit 4, executive unit 6, alarm unit 7 and visual indication unit 8, similar units of manufactured devices and safety systems (load limiters) of lifting machines can be used . As the loss factor 5 in the block of the tackle block, memory cells of the memory devices of the controllers acting as digital computing units 4 can be used, or they can be implemented in hardware, for example, using a variable resistor.

The load limiter works as follows.

In the digital computing unit 4, based on the signals of the sensors 1, 2 and 3, taking into account the value of the coefficient kr of losses in the block of the pulley block set by the adjuster 5, the values of the forces on the load-gripping body Ph in the cargo rope Pr are determined. The force in the cargo rope is associated with the force on the load gripping body (hook) by the expression:

Where:

Pr is the force in the cargo rope at the place of installation of the sensor 2;

Ph is the force acting on the load-gripping body (hook), determined by the signals of the sensor (s) 1;

kr is the loss coefficient in one block of the pulley block, determined by the setter 5;

N - the multiplicity of the pulley block (reserve) of the cargo rope.

The plus or minus sign in expression (1) is determined by the installation location of the sensor (s) 2 (in the fixed or on the movable branch of the cargo rope) and the direction of rotation of the cargo winch, which is determined by the signals of the sensors of discrete signals 3.

From here you can calculate the actual value of the multiplicity of the chain hoist of the cargo rope according to the formula:

The obtained values of the efforts are compared in the digital computing unit 4 with the passport value of the vehicle load capacity at a given point of the load characteristic and the allowable force acting on the rope. When the force Ph exceeds the carrying capacity, block 4 generates and sends to the actuating unit 6 a signal to turn off the movements of the lifting machine, aimed at increasing the load moment and reducing the carrying capacity (lifting the hook, increasing the reach, etc.). If the force Pr exceeds the permissible load in the cargo rope, block 4 generates and sends to the actuating block 6 a signal to turn off the movements of the lifting machine, aimed at increasing the force in the cargo rope (lifting the hook, lifting the boom, etc.).

Simultaneously with the shutdown of the mechanisms of the lifting machine, the digital computing unit provides a signal to the alarm switching unit 7. At the same time, information on the numerical values of the forces Pr, Ph and the actual multiplicity of the chain hoist of the cargo rope N is transmitted to block 8 of the visual indication from block 6

Claims (1)

The load limiter of the lifting machine, including a digital computing unit, the outputs of which are connected to a visual display unit, an alarm unit, an executive unit, and to the information input are connected the outputs of peripheral devices for recording crane parameters, characterized in that the peripheral devices for recording crane parameters include sensors for determining loads on the load gripping body, sensors for determining the force in the cargo rope, as well as sensors for the direction of rotation of the drum oh winch connected to the data inputs of a digital computing unit, and to an additional input of a digital computing unit connected dial loss factor in a goods chain hoist block.