Articulated Boom Crane Load Moment Indicator

Articulated Boom Crane Load Moment Indicator also known as crane LMI or crane Safe Load Indicator (SLI) is a safety protection device applied to boom type lifting machinery, it can prevent the crane due to overload and operation errors caused by accidents, so that the safe use of the crane to achieve standardization and scientific. Its essence is a safety accessory to provide overload protection, often used in lifting equipment, lifting torque once exceeded the limit can automatically break, stop action to protect the equipment.
The Load Moment Indicator uses the moment balance principle to calculate the actual lifting load. According to the principle of moment balance, the equivalent mass of the boom at the head position is calculated when the boom is not loaded. Because the equivalent mass of the boom is different at different lengths and angles, an infinite number of values need to be calibrated.
Because of the existence of boom, the algorithm of Load Moment Indicator is different from that of truck crane, so a specific no-load calibration algorithm should be proposed to equate the dead weight of boom and boom in the boom head. According to the structure and force characteristics of the crane with folding arm, the mathematical model of the working device is established, and the no-load calibration is realized by calibrating the weight and center of gravity of the lifting arm.

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SZ-AB100 Articulated Boom Crane LMI

Product Overview

The SeeZol Articulated Boom Crane Load Moment Indicator, also known as crane LMI or crane Safe Load Indicator (SLI), is a safety protection device applied to boom-type lifting machinery. It prevents accidents caused by overload and operation errors, bringing crane use to a standardized and scientific level. In essence it is a safety accessory that provides overload protection—once the lifting torque exceeds the limit, it can automatically break and stop the action to protect the equipment.

Because articulated (knuckle-boom) cranes have multiple boom sections and complex geometry, the LMI fuses several angle and pressure inputs to compute the true lifting moment and enforce the rated capacity envelope through every articulation. It prevents overload and tipping for forestry, truck-mounted, and industrial lifting where the boom folds and swings in tight spaces.

Applicable Models

Knuckle-boom cranes, articulated cranes, and truck-mounted folding cranes.

Key Features

  • Real-time data display: weight, height, radius, angle
  • Overload and over-range danger warning
  • Overload record storage (approx. two weeks)
  • Customizable wireless transmission for remote safety monitoring
  • Multi-section boom moment calculation

System Parameters

  • Working voltage: DC 12–36V
  • Working temperature: -20℃ ~ +70℃
  • Storage temperature: -20℃ ~ +70℃
  • System error: ±3%
  • Display error: ±5%
  • Relay contact capacity: AC220V 3A
  • Protection level: IP65

Main Components

  • Cabin display (HMI)
  • Hydraulic pressure sensor
  • Angle sensor (per boom section)
  • Control unit / processor

Application Case

A forestry operator deployed SeeZol articulated-boom LMIs on truck-mounted cranes, preventing overload during log handling where boom geometry changes constantly.

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