The brake is an integral part of the crane system. Adrian Greeman analyzed the development of this component.

Without brakes, no lifting system can operate successfully. Not only must the load be lifted, and then moved in some way on the track, trolley, gantry to be placed elsewhere, but also must be stopped when they reach the correct position, before that, if they collide with other activities Danger. The provision of brakes is essential for proper load management and safety.

These inconspicuous components have their own development paths. At least three main trends can be seen in technology and use; the emergence of disc brakes to replace drum brakes, modern factories, mines and other uses (especially theaters) are important for safety The increasing emphasis on sex and the increase in the use of electronically controlled variable frequency motors, its "unlimited speed" has changed the role of the brake. Since the motor slows down the speed of the load, brakes are now usually used to hold and fix the load, rather than slowing down its movement speed.

Historical development Perhaps the most obvious of these developments is the emergence of disc and caliper brakes. Vice President of Sales for Hilliard Corporation, a US manufacturer and distributor. Juan Parra described this development: "Drum brakes, an external shoe brake, were most commonly used in the post-war period, rather than the internal drum brakes you see in cars. ."

However, with the development of automotive disc brake technology, it has also begun to be used in industrial applications. He said that the British company Twiflex provided one of the first types of caliper discs, which is now part of the Altra Industrial Motion Group. These do not use drums, but instead use a disc that is connected to a rotating power transmission shaft with clamping calipers and brake pads.

Parra said: "The disc type has significant advantages." The most important thing is the way the brake can disperse the large amount of heat that is always generated by braking friction. "Most drum brakes are more accessible on one side than the other, and the heat is radiated unevenly from one side.

He said that another type of brake, the disc brake, has bigger problems. The plate brake has a sandwich of multiple friction linings and braking surfaces, providing a large number of braking surfaces in a compact space, which is sometimes useful, but "there is no simple way to dissipate heat."

If the brakes are only used occasionally, such as on the landing gear of an aircraft, and there is time to cool down again, it can be overcome. "But not suitable for regular use."

The problem with new materials causing hearing loss through a surface is that hearing gradients can cause material swelling and other effects, which, he said, in turn can lead to cracking or other problems. He said that new materials are being developed to help achieve this, but the symmetrical structure of disc brakes allows for more uniform dissipation and greater material stability.

Another advantage of disc brakes is that they can handle greater torque. Over the years, this has moved the position of the brake from the motor drive shaft to the gearbox output shaft, which rotates faster but has higher torque. He said that disc brakes can also be made in larger sizes, and the drum size is limited to 30 inches (750 mm).

"Another development is further braking on the cable drum itself," he said. This requires the drum to have an enlarged flange that acts as a brake disc on the outside.

The advantage is that the braking action is further along the connection, and if the transmission device is damaged, it provides higher safety; if the gear train is damaged, it is useless to stop the motor output.

"In most cases, the drum is not made this way, but you can modify it by welding or bolting," he said.

Drum brake An extension of the drum brake is the addition of various safety braking systems, especially in elevators and some theater stage equipment. He said that the brakes are installed on the roof of the cab and run on vertical tracks. Sudden acceleration activates to clamp and stop.

Systems like this are also used in mines for explosives vehicles that run to the working surface.

Pella said that Hilliard made some of its own brakes, especially very large brakes; the largest of which was a mobile stage setting on one of the large theater stages in Las Vegas.

These are hydraulically activated instead of using electromechanical methods to open the calipers of most disc brakes. The hydraulic method has more pressure to push away the springs on very large brakes. As with all these braking systems, the calipers must be actively opened during operation, creating a "fail-safe" condition, and if the power fails, they will shut down.

"But we also bought a lot of our brakes from Twiflex and are the North American distributors of their products," Pera said. It covers a wide range of industries, from paper mills to mining, from steel mills to shipyards, and other marine applications. From scenic lifts in operas to scoreboards in stadiums, drama and sports are also widely used.

A wide range of Twiflex also provides its products directly in the UK, of course serving a wide range of industries. One major application is in custom mine hoist systems provided by leading manufacturers.

The supplier designated Twiflex VMS3/SPS brakes for the US$1.4 billion Goldcorp Eleonore gold mine in northern Canada, which has an ore throughput of 7,000 tons per day. In the next 15 years, it should produce 600,000 ounces/year of gold, making it one of the largest underground mines in Canada. Production will start at the end of next year.

The order is for the installation of calipers for a huge double-drum single-clutch mine hoist with a diameter of 20 feet (6.1 meters). The hoist has two brake discs, one on the fixed drum and one on the clutch drum.

Each brake generates 240kN braking force under a 2.5mm air gap, which can provide more than 2 million cycles of fatigue life under this rating. The company also provides VMS-DP brake calipers with bases and hydraulic power packs for each of the two main rolling mills.

Twiflex stated that VMS3/SPS is a sturdy design, which is characterized by a reinforced shell that can accommodate additional springs to increase braking force. It is completely sealed to prevent corrosion and dust.

"The brake design provides set-up and maintenance advantages, including tamper-proof pad/air gap adjustment, external pad retraction, on-site torque adjustment and a'parking' function, and the seal can be quickly replaced without special tools," said the company. The seal can be replaced from behind without removing the brake from its installation.

Braking force The design uses a small size piston to speed up the response time, combined with an improved drainage system and a reduced 137 bar retraction pressure at this rating. By adding or removing the gasket located behind the back cover, the braking force can be easily changed to 275 kN with a 3 mm air gap. The brake can be equipped with sensors to signal brake on/off and brake pad wear.

Europe is also home to many other major supplies, especially in Germany. One of the most famous companies is Mayr, which provides products to many major crane manufacturers, including Finland's Kone Cranes.

"For cranes, we usually use disc brake types," said Petri Partanen, product support manager for cranes and crane manufacturers. "They were sued to stop loading." He said that bridges or carts also need brakes. "The most important thing is that emergency brakes are usually drum brakes that can hold the load in the event of a failure."

He said that for crane structures, electromagnetically operated spring-loaded disc brakes are the norm. "We sometimes also use compact brake motors, where the activation of the motor releases the brake through the axial movement of the shaft."

But he added that for high-risk operations such as molten iron manufacturing or mining, it is important to keep the brake independent of the motor. "Under these conditions, if the load increases suddenly, an additional brake is mechanically activated."

Safety First Mayr Marketing Manager Helmut Kleinheinz said that safety is an increasingly important consideration for braking systems, especially as variable frequency control motors become more and more common. The use of finely controlled speed on the motor means that the load is usually decelerated by the motor itself rather than the brake, which means that the brake is more used to hold the load when it is static.

However, although this reduces the requirements on the brakes and in particular changes the wear experienced by the brakes, it is still crucial to calculate the brake capacity required for falling loads. In the worst case, when problems may arise, it must be the foundation.

Meyer provides a wide range of brakes for different industries. One with special safety requirements is theatrical elevator used in operas and theaters to lift heavy scenes, and the danger of elevator failure is obvious. At the International Eurovision Song Contest held at the Düsseldorf Arena two years ago, Meyer's brakes were prosecuted in a special case when the competition became the world's largest television studio.

For complex scene changes, stage elements weighing several tons had to be moved over the heads of 35,000 powerful spectators and artists. The power transmission stage brake is integrated into the chain hoist to ensure safety.

In order to transform the football field, more than 40 large trucks are needed for the stage alone. Approximately 120 trucks of the same size are needed to transport lobby lighting, LED technology, 2,200 lighting fixtures and audio equipment. In order to suspend lighting and decorations on steel cables and chains, maximum safety requirements are required. During the performance, most of the movement of the stage elements used chain hoists with power transmission safety brakes.

Important standards Mayr enables theater cranes to meet the different standards required by German law. All electric chain hoists for stage technology must meet the BGV standard, but the basic standard only allows no one to move below, and the load can only be moved for setting when no one is present.

For the live movement of people, there is a stricter standard saying that Mayr and crane must have two independent DC voltage brakes. They belong to the ROBA-stop-silenzio or ROBA-secustop series, and Mayr was specially developed for this purpose.

The compact and closed design ensures simple operation and installation. It says that the working air gap is preset and does not need to be re-adjusted. Faults caused by operation and adjustment errors are excluded.

“The device has an integrated damping system to reduce noise and achieve maximum operational safety and reliability. Each brake in the factory is 100% inspected before delivery to ensure its completion,” Meyer said.

The stage brakes are mainly maintenance-free. Maintenance is limited to the inspection of high wear-resistant long-life friction linings. Mayr can provide cranes that meet the highest standards for use in moving scenes during performances and multiplayer events.

The company said that extremely quiet stage brakes through power transmission will be shown in numerous events around the world every day. Another important German crane brake manufacturer is Intorq, which was once part of the Lenze Group and is now an independent subsidiary, but it is still Lenze's main supplier. Many important crane brands use its devices-in the UK, Street Crane uses them, and they also supply Konecranes.

Geoff Spear, Lenze's UK marketing manager, said that their purpose of manufacturing brakes is very wide, and they are not just focusing on the crane market. But within this range, there are many models used in the crane market, including the Intorq BFK468 spring-operated brake for high-performance applications, where the driver generates higher motor speeds and drive torque.

"Despite the ever-increasing performance requirements, there is less and less space available for brakes," Lenze said. For this innovative multi-pole technology, even if the force is large, it can be released through a large air gap. Larger working air gap means longer maintenance intervals

These units have fixed or adjustable braking torque, and can be "cold braking" by maintaining current derating.

More directly used for hoists is the BFK468 multi-pole brake, which has high braking torque, short response time and low noise operation. They can also be adapted to the contour of the motor.

Spring-operated brakes use calipers and are used in multiple and redundant arrangements. It has no residual torque and quiet operation when it is released, can "cold brake" and can use microswitches for air gap or wear monitoring.

Growth trend One growth trend is the use of compact design brake motors. The Italian company Coel Motori specializes in the production of four different series of brake motors.

The first is Type F, enclosed and externally ventilated. The brake group and all motor components are designed and manufactured by Coel. The brake group is provided in series with the AC three-phase electromagnet, but the DC version is also available.

The FK motor is a DC motor with a rectifier. Like the F-type motor, it can be driven by an inverter, but this means that the power supply of the brake and the motor is separate. They have a molded aluminum housing and cast iron braking surface.

The last series of SW is suitable for situations where the motor is frequently exposed to water. The brake motor is not ventilated and completely enclosed.

Coel is sold in large quantities to the oil and gas industry, especially in environments that require explosion protection, there is a new modular explosion-proof brake VIS. Coel marketing manager Alessandro Tonon (Alessandro Tonon) said it has a patented design suitable for hazardous areas.

"The device is designed for a variety of applications, such as lifting and traveling applications, winches, winches, wire rope hoists and chain hoists," he concluded.

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