Malmedie goes lightweight
NewsGerman coupling specialist Malmedie has developed a new Evolution Torque Safety Coupling, which it displayed for the first time at TOC Europe 2023, being held this week at Rotterdam Ahoy.
Malmedie evolves into system provider
The well-known German coupling specialist Malmedie is on a journey to extend its product range and become a system provider.
Malmedie is known in the crane industry for its pioneering inventions, such as drum couplings for hoists in the 1960s and the safety coupling in the SOS platform (Snag Overload System) developed with Dellner Bubenzer.
To provide more value to the market, Malmedie is now developing “holistic solutions” for drive trains, said Thomas Netz, Managing Director at M.A.T Malmedie Antriebstechnik GmbH.
This shift in strategy is embodied in four new product lines: EvoDrum, LifeMonitor, EvoTorque and EvoHoist. EvoDrum and LifeMonitor are available today for specification and purchase, while EvoTorque and EvoHoist are still in development, along with other new products on the Malmedie product roadmap.
New approach to drum couplings
EvoDrum is a new longer-lasting barrel roller coupling for a hoist drum with a Duplex Hub design.
As Netz explains: “Drum couplings play a crucial role in absorbing radial forces caused by the pull on the hoist rope, in addition to transmitting torque. They generally come in two types: gear couplings and barrel roller couplings. Gear couplings, designed primarily for torque transmission, tend to suffer rapid wear on the tooth flanks due to radial forces. In contrast, barrel roller couplings, which are engineered to handle both radial forces and torque, offer a longer service life and exhibit linear wear behaviour.
“The EvoDrum, the latest innovation in drum coupling design, features a reusable Duplex Hub with a second set of grooves that effectively doubles the coupling’s lifespan. This innovative feature not only reduces costs but also showcases Malmedie’s commitment to sustainability. Additionally, the housing is shipped directly from stock, minimising procurement time and cost. By eliminating the need for additional manufacturing or confirmation drawings, direct delivery streamlines the entire process.”
To further improve lifecycle performance Malmedie is now offering LifeMonitor, a condition monitoring system that uses sensors to track the condition and operating parameters for couplings. “With up to 0.1mm increments, the LifeMonitor provides precise, real-time data on coupling wear on up to eight drum couplings, allowing for proactive maintenance and extended equipment life,” Netz said.
During product testing, LifeMonitor identified abnormal wear behaviour on a main hoist on a container crane. “After intervention and support from Malmedie’s coupling experts, who pinpointed an alignment issue as the root cause, the wear behaviour was restored to normal levels,” Netz said.
As a remote monitoring system, LifeMonitor eliminates the need for in-person inspections. The system is available for both new and existing hoists, and can be installed with other brand couplings (subject to analysis). The space requirement is a 100mm gap between the coupling housing and the gearbox.
Data from the monitoring system can be transferred using protocols including Profibus, Profinet, CANopen, MQTT, analogue (0/4-20mA), VPN, and LAN. The system hardware is installed in an IP65 housing for durability.
Addressing overloads
The SOS was developed to provide mechanical protection to the main hoist gearbox and other drive crane components in the event of an overload situation. One of the most dangerous scenarios for a container crane is the spreader getting stuck suddenly in the cell guides during hoisting (a snag event), potentially causing severe damage to the drive train and the crane structure itself.
“Various snag protection designs exist, but only mechanical overload protection systems, such as the SOS, address the root cause directly. These systems separate the overload from the hoist, preventing the abrupt stop that can introduce potentially damaging inertia into the system,” Netz said.
The core of the SOS system is the Malmedie Safety Coupling (MSC), which is positioned between the motor and gearbox. When overtorque is detected, the MSC releases the load from the drivetrain, allowing the hoist motor to continue rotating independently of the main hoist gearbox, thereby protecting surrounding components.
The original MSC in the SOS needed to be manually reset after it was tripped by hammering part of the coupling back into place with a rubber mallet. This required someone to go up the crane and into the machinery house and reset the system. EvoTorque, the latest iteration of the MSC, offers significant improvements. It is designed to be 20% lighter and has 50% less inertia.
“Crucially, EvoTorque not only releases but also resets mechanically, making it automation-ready and ensuring minimal maintenance and quick resetting after a torque event,” Netz explained.
Malmedie is now working with Dellner Bubenzer to integrate EvoTorque into the SOS system. Enter EvoHoistIn a separate development, Malmedie has designed the EvoHoist platform, a new configuration for the main hoist system that integrates all the braking functions on the low-speed side of the system. This eliminates the need for service brakes on the high-speed side of the hoist (between the hoist motor and the gearbox). The main system components for EvoHoist are the EvoTorque safety coupling, a specialised hydraulic power unit, a PLC, and EvoBrake.
“EvoHoist significantly reduces inertia in the main hoist (>25%), as the brake disks on the high-speed side are not needed anymore. This leads to energy savings and reduced wear on the gearbox. This system is designed for sustainability and cost efficiency throughout its lifecycle,” Netz said.
Preparation is now underway for field tests. Depending on the project and crane specifications, the system can be retrofitted.
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