Ball Swivel Joints Safely Swiveling and Rotating 308 Metric Tons

Related Vendors

Rodriguez GmbH

FAULHABER Drive Systems

Taiwan Machine Tool & Accessory Builders' Association (TMBA)

Swing mechanisms in harbor cranes must transmit forces precisely and without play, even when handling heavy loads. That is why Peiner installs specially adapted spherical rotary joints with double-row four-point bearings from Rodriguez. These joints combine high load-carrying capacity and tilt stiffness with a compact design.

Peiner SMAG Lifting Technologies, based in Salzgitter, primarily manufactures grabs used to load and unload bulk carriers. The company has approximately 5,000 variants in its product lineup. In addition, it offers swivel assemblies in which Rodriguez ball-type rotary joints play a key role. 

[...] our swivel units are subjected to harsh harbor operating conditions, where both load limits and maintenance intervals are often pushed to their limits.

Tobias Biel, Technical Buyer, Peiner

Swing mechanisms ensure precise rotation and positioning of loads and are standard equipment on modern harbor cranes. One of the main mechanical components is the rotary joint. It ensures that two assemblies can be rotated or swiveled precisely relative to one another, even under very high axial and radial loads as well as tilting moments. Peiner uses special ball rotary joints in its slewing mechanisms so that heavy loads can be rotated in a controlled manner and positioned precisely at the crane hook, even during prolonged operation.

Special Requirements for Load-Bearing Capacity and Stability

High load capacities of up to 308 metric tons, yet with extremely limited installation space—the rotary joint used must perform under demanding conditions. Four-point bearings with two separate rows of balls have proven effective here. They can handle very high loads, require relatively little space, and are cost-effective to manufacture.

Double-row four-point bearings are extremely reliable in dynamic swivel applications.

Martin Stremmel, Productmanager, Rodriguez

Double-row four-point bearings accommodate both axial loads in both directions and radial loads. This makes them suitable for the rotary joint in the swivel mechanisms, since the slewing ring supports the entire weight. Compared to single-row bearings, they also offer the advantage of significantly higher torque capacity and tilting stiffness. When tilting moments occur, the upper row absorbs tension/compression and the lower row absorbs the counterforces, resulting in high bidirectional capacity. 

Martin Stremmel, product manager at bearing manufacturer Rodriguez, explains: “Double-row four-point bearings are extremely reliable in dynamic swivel applications. They can withstand frequent starts and stops as well as fluctuating loads. Compared to cross-roller bearings, they are generally less sensitive, more shock-resistant, and also easy to install.”

Specially Designed Raceways, Screws, and Gear Teeth

For the application at Peiner, the experts at Rodriguez customized a double-row, externally toothed ball rotary joint to meet the customer’s specific requirements. Despite its compact dimensions, it is capable of handling the very high load requirements. “Load-carrying capacity and a long service life are particularly crucial here, because our swivel units are exposed to harsh port operations where load limits—as well as maintenance intervals—are often pushed to their limits,” said Tobias Biel, Technical Buyer at Peiner. In particular, the raceways, screws, and gearing were specifically designed for this application.

A Long-Standing Partnership Pays Off

For many years, Peiner, a manufacturer of swivel mechanisms, has relied on Rodriguez rotary joints—both as standard components and in special designs for demanding applications. “We particularly appreciate their delivery performance and design support,” says Tobias Biel. “We receive reliable deliveries every time.” 

The added value of this long-standing partnership is particularly evident when special swivel joint applications are needed on short notice. “We frequently encounter specialized applications that Rodriguez quickly evaluates and tests for suitability. If necessary, Rodriguez manufactures additional custom ball joints tailored to our specific application,” explains Biel.

He emphasizes that communication between the user and the supplier takes place in an atmosphere of trust and on an equal footing: “We are completely satisfied with the advice and service because we have a partner by our side whom we can rely on.” Thanks to quick response times and reliable points of contact, technical details can be clarified promptly and deadlines met, even for last-minute projects with demanding requirements. The next project is already in the works: Discussions are currently underway regarding follow-on production of the series product, which will continue the collaboration.

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