����������� �����������������

PROLINK SYSTEM MANAGEMENT SAFETY DEVICES

The “Prolink” system, which gives considerable advantages from the point of view of crane operation in the case of low entrances or within buildings with reduced headroom, or anywhere involving horizontal positioning of the crane, may result in potentially dangerous situations when the crane is used in a vertical position.

In effect, as the angle of opening of the outer boom or hydraulic jib increases, the vertical stop on the inner boom will, if not limited, allow a negative loading condition to be created on the vertical line, resulting in structural instability in the crane and a state of extreme danger. The Fassi Prolink safety function, controlled using the parameters in the crane safety device electronic management program, automatically determines the variation in maximum verticality of the inner boom according to the state of the prolink function.

Situation that arises

with Prolink without safety

devices

It also notifies the operator, with the message “Warning angle” that appears on the radio remote control and user control panel displays, that the crane is about to reach the maximum authorised vertical angle. At the same time, the red light starts to flash and the beeper starts to sound. During this phase, if lifting continues, the lifting rams speed is automatically reduced to ensure that, at end of stroke, the load inertia does not determine a state of instability on the extension booms. When the maximum vertical limit is reached, the message “Max angle crane” appears on the display, and all further lifting operations are blocked.

Situation “Prolink

with Fassi safety

devices”

20-1

For cranes with the Prolink function, the position of the booms is read by an angle sensor located on the crane’s outer boom and/or hydraulic jib. The angle of both the outer boom and the hydraulic jib boom with respect to the horizontal position of the crane is shown on the radio remote control and user control panel displays, so that the crane configuration can be kept under control at all times.

Photo of angle sensor As can be seen from the above, safety during use of the Prolink system is guaranteed and automatic, with nothing being left to chance. Many other crane manufacturers, on the contrary, deal with the risks that may arise when using this device simply by indicating in the user and maintenance manual that great care should be taken when operating with the crane in a vertical configuration, or that this type of operation should be avoided, thus leaving all the responsibility to the operator (see example).

Advantages for the operator: • Safe and fully automatic management of the Prolink system, with the ability to highlight and

control operation of the crane using the information provided on the radio remote control or user control panel displays.

20-2

Working of the crane

In some crane, the articulated boom can be extended further the angle of the inner boom. In the upper movement area (B area, approx 60° until the max angle of the iner boom), this position of the articulated boom must not be used as working position.