German crane builder Demag Cranes and Components has begun serial manufacture of the DR wire rope hoist launched late last year. With it a new design of wireless remote control unit has also entered serial production
Although the control was available as an option when the hoists launched – between 100 and 200 have been sold, according to the company – large-scale production began in July.
Like many joystick-based remotes, the device controls the hoist’s frequency-inverted trolley and travel motors. But it does all of this using push buttons.
“Our intention is to avoid joysticks – the transmitters are large and not so ergonomic,” said product manager Stefan Elspass. Instead, the device uses an unusual design to make the push buttons infinitely variable.
The push-button switch works differently than most on/off controls. Instead of a pushed button physically touching a matrix, the new Demag control works by proximity. Underneath a button, a small permanent magnet generates a magnetic field. The harder the button is pressed, the closer the magnetic field to the sensor, the stronger the signal, and the faster the crane’s movement. The signal does not increase in direct proportion to physical proximity, but instead is very sensitive at low speeds and has a more rough adjustment at high speeds. Exactly how much the crane speeds up depends on preset ranges.
Demag has also made upgrading to a wireless remote easier. All of the controls, and the antenna, have been built onto a printed circuit board that slots into the side of the hoist. Elspass claims it takes two minutes to swap a wireless remote for a cable control.
Both pendant and wireless control have an integrated display. But the wireless model is claimed to have more sophisticated graphics. “It has a lot of functions already known from cellular phones – battery status, hints, warnings coming from the hoist,” Elspass said. This makes sense, given that manufacturer of the controls is former mobile phone manufacturer Ericsson.
They also both have an infrared data port. This can relay maintenance and repair information to a suitably-equipped laptop PC. A single control – wired or wireless – can also control up to two hoists at the same time.
At the end of the year the company will release a wireless control for the DC chain hoist, which was launched earlier this year.
A wireless remote control to be retrofitted to older contactor-controlled hoists is expected to go on sale in January.
“Our expectation is up to now 40% to 50% of standard cranes are fitted with remote controls, and process cranes are practically 100%,” Elspass said. “It is very necessary to have that function integrated with wire rope hoists.