Crane radio control system augmented with joystick

Previously, operators had a choice of two systems for the radio control of cranes; either a compact unit with pushbuttons or a large control unit with joysticks. The Demag DRC-MJ controller combines joystick control of all motions with the ergonomics of a compact hand held unit. 

The housing of the new control unit is based on the proven design of the Demag DRC DC hand held transmitter. The impact resistant housing material has a smooth surface and is resilient to mechanical loads. Rubber coated end caps ensure durability, making it suitable for operation in arduous environments. The batteries may be used for uninterrupted operation for up to five days without recharging.

The design replaces the conventional keypad panel of a compact controller with two integrated mini joysticks and four buttons. The lifting and lowering motions of a rope hoist may be controlled accurately using the top joystick. The lower joystick may be used for the variable control of two motion axes, such as two crane and travel functions. Simultaneous motions, including diagonal long and cross travel motions, can be controlled with one hand, speeding up the material handling process.

The lifting and travel motions may be limited, at the press of a button, to 30, 50 or 70% of the maximum speed for each motion axis. When the speed limit function is activated, the maximum deflection of the mini joysticks is used for the reduced maximum speed. This results in a ‘zoom’ function, which enables very fine control of slow speeds for optimum positioning accuracy.

A distinct and illuminated bi-colour display shows the weight of the load. A vibration alarm indicates an overload and other status messages, relevant for safety and service purposes, may also be provided. Four user friendly buttons complete the control concept of the DRC-MJ units. 

For all Demag D3 radio control systems, the operator can pair each crane with up to three transmitters of various types; conventional pushbutton transmitters, classic joystick transmitters or mini joystick transmitters, with the ability to switch from one to another at the press of a button. This enables control of the crane to be transferred from one worker to another for greater efficiency of material flow.

The D3 generation of radio controls is equipped with frequency hopping and “listen before talk”. These features ensure radio transmission which is highly resistant to interference and compatible with other radio applications, even under arduous conditions. Up to 40 DRC radio systems may be operated in close proximity to each other.

Dr. Thomas Bönker, senior director of the Components’ Business Line at Terex Material Handling explains: “With our new DRC-MJ hand-held transmitter, we meet the demands of younger workers, who have grown up with modern control systems, such as joysticks and thumbwheels. The control concept will also be welcomed by older workers, as it facilitates ergonomic control of simultaneous travel motions with just one hand.”