An extra touch of luxury: Electric windows for yachts

• What was needed: ZLW toothed belt axes, DC direct current motor, D5 direct current motor output stage
• Requirements: Electrical components must not only be compact at sea, but also resistant to aggressive salt water and high temperature fluctuations. They must also be as maintenance-free as possible.
• Industry: Ship and boat building
• Success for the customer: As the toothed belt axes have a very low clearance height, they are the ideal solution for light adjustment and positioning tasks where space is limited. The toothed belt axes are also corrosion-free.

Glaskeil, founded in 1898 by master glazier August Keil in Würzburg, has developed into a specialist for ready-to-install and custom-made glass and plastic products for yacht building.

Electric windows offer more comfort and luxury than conventional windows, as they can be opened and closed at the touch of a button. While this has long been standard in cars, such windows are still a rarity on yachts. Here, electrical components must not only be compact, but also resistant to aggressive salt water and extreme temperature fluctuations. In addition, they should be as maintenance-free as possible.

"The search for a supplier of electric linear guidance technology that meets the high requirements of luxury boat building was correspondingly challenging," recalls Glaskeil developer Mirco Eisenhauer.

The designers at Glaskeil faced several challenges: The products had to be very space-saving, as room is limited on boats. Corrosion, especially from salt water, is also a major problem.

As these are boats in the premium segment, the motors installed should be as maintenance-free and quiet as possible in order to offer customers a satisfactory experience. The control system should also be convenient. Modern programmable logic controllers (PLCs) are often oversized for simple automation tasks such as raising and lowering a window pane.

"At igus in Cologne, we finally found a system that is space-saving, robust, wear-resistant and virtually maintenance-free. And thanks to the plug-and-play principle, it saves us design work."

The main component of this solution is the drylin ZLW series of toothed belt axes, which are installed along the longitudinal struts of the black window frame on the right and left. With a clearance height of only 31 millimetres, these toothed belt axes are the perfect choice for light adjustment and positioning tasks, especially when space is limited.

The windows are driven by a DC motor from igus. With a flange dimension of 42 millimetres, this motor is also very space-saving, as it does not require a motor flange, coupling or complex external power electronics. It is also resistant to a wide temperature range between -10°C and +60°C. When the yacht passenger presses a switch, the motor starts up. The toothed belts, connected to each other by a synchronous shaft, then move on both sides of the window frame. And with them the slides mounted on the profile guides, to which the window pane is in turn attached.

The slides glide on the aluminium rail with the help of WJ200UM series pillow blocks via high-performance plastic bushings. Thanks to microscopic solid lubricants, hygienic, low-friction and quiet dry operation without external lubricants is possible. This keeps maintenance requirements to a minimum.

Glaskeil also uses the dryve D5, an igus motor control unit that enables quick commissioning. Design engineers only need to connect the power supply, control signals and the motor to the end stage. A signal triggered by a connected pushbutton then starts and stops the motor. A second signal changes the direction of rotation. The speed of the output can be adjusted via eight microswitches on the housing. Optional adjustment via smartphone, tablet or laptop is also possible. Using an intuitive browser interface, Glaskeil can then set the travel mode, positions, accelerations, speed and pause times of the linear axes in just a few minutes. The high rated current of 10A and 30A peak current also enables powerful and dynamic movements if required.

Another advantage is that, thanks to a sophisticated combination of materials and microchips, the power amplifiers operate particularly quietly and with low vibration at all speeds. "We don't have to worry about annoying noises that can occur with many inferior power amplifiers," emphasises Mirco Eisenhauer. "This is an important point for our customers in the premium segment."