Brochure "Snag overload system" (SOS)

Product catalog summary

Introduction to Snag Overload Systems
The document discusses the Snag Overload System, a safety mechanism designed to prevent damage during crane operations when a sudden stop occurs due to an obstacle. This system is crucial for high-speed hoisting operations where conventional load cells and PLCs are insufficient due to delays and motor inertia.

Definition of Snag Load Case
A snag load case occurs when a crane's spreader is abruptly stopped by an obstacle, causing an extreme overload. This can lead to broken ropes and gears if not managed properly.

Conventional Hydraulic System
Traditional systems use electronic load cells and PLCs to open hydraulic valves, allowing cylinders to absorb the load. However, these systems require high maintenance, are heavy, occupy significant space, and react slowly.

Mechanical Snag Overload System (SOS)
The Mechanical SOS uses a Malmedie Safety Coupling (MSC) to instantly disconnect the motor drives from the gearbox, significantly reducing drive inertia with LiTec® brake discs. This system reacts within 5ms, is lightweight (500 kg), requires minimal maintenance (3 hours annually), and is suitable for retrofitting.

SOS Principle and Components
The system includes components such as the MSC, LiTec® brake discs, thruster disc brakes, emergency brakes, and a PLC. These elements work together to separate the motors from the drive, minimize inertia, and control the braking process.

Operation and Scenario
Upon detecting a snag load, the MSC mechanically separates the motors, and the PLC activates the safety brakes within 30 ms. The hoist stops within 100 ms, and the service brakes take over. The crane operator can then safely lower the load, and a brief inspection ensures no damage has occurred. The system can be reset in 5-10 minutes.

Conclusion
The Mechanical SOS offers a rapid, efficient, and low-maintenance solution for managing snag load cases in crane operations, enhancing safety and reducing downtime.

Catalog excerpts

Snag Overlaod Systems. Made in Germany.

Open the catalog to page 1

Definition Snag Load Case • Sudden stopping of an empty or loaded spreader in a ship cell or other obstacle/barrier during the hoisting procedure of a crane. • Especially at high speed hoisting a sudden and extreme overload occurs. • Even a detection with conventional load cells does not provide stopping of the hoist fast enough due to slow PLC delays and motor inertia. Consequences 1 Broken ropes 2 Broken gears 3 or even worse

Open the catalog to page 2

Snag Overload System Motor Malmedie Safety Coupling MSC (see Malmedie catalogue) Malmedie Gear Coupling (see Malmedie catalogue) PINTSCH BUBENZER LiTec® brake disc PINTSCH BUBENZER thruster disc brake SB28 with VSR unit (see data sheet A04) PINTSCH BUBENZER emergency brake SF with CMB unit – fast setting execution (see data sheet B03) PINTSCH BUBENZER SOS PLC Malmedie Drum Coupling TTX (see Malmedie catalogue) PINTSCH BUBENZER power unit (see data sheet B04) Conventional Hydraulic System • A snag load case is detected by electronic load cells. • A PLC opens a hydraulic valve and large hydraulic...

Open the catalog to page 3

A Snag Case B SF brake closed C 90% contact force SF brake Snag Load Case •At a Snag Overload, safety elements of the MSC mechanically separate the motors from the drive without exceeding an adjustable maximum torque. • The remaining inertia of the drive is minimized by using LiTec® brake discs. • Sensors detect the trip of the safety elements and an ultra fast PLC closes the safety brakes. • When the service brakes are closed, the safety brakes will be opened again. The rope drum is held by the service brakes only. • The crane operator can now let down the load by using the hoist master switch. A...

Open the catalog to page 4

PINTSCH BUBENZER GmbH Friedrichshüttenstr. 1 D-57548 Kirchen-Wehbach Telefon +49 27 41/94 88-0 Hünxer Str. 149 D-46537 Dinslaken Telefon +49 20 64/602-0 www.pintschbubenzer.de

Open the catalog to page 5

Brochure "Snag overload system" (SOS)

Brochure "Snag overload system" (SOS)

Catalog excerpts

All DELLNER BUBENZER Germany GmbH catalogs and technical brochures