Lifting device provided with an auxiliary device for counteracting tipover of the boom in sudden loss of load

A lifting device comprising a force-absorbing base to which a boom with hoisting cable for lifting a load in substantially vertical direction is tiltably connected, wherein the lifting device is further provided with an auxiliary device for counteracting tipover of the boom in the case of sudden loss of load, wherein the auxiliary device is connected to the base of the lifting device, provides a contact surface which comes into contact with a contact surface of the boom in the case of tipover, and further comprises a drive and control system which is configured to stop the boom movement when a predetermined force between the contact surfaces is exceeded as a result of the boom tipping over;

• wherein the drive and control system is configured to hold the contact surface of the auxiliary device and the contact surface of the boom at a small mutual distance so that the boom is only capable of limited acceleration during tipover;
• wherein the drive and control system comprises measuring means for measuring the mutual distance between the two contact surfaces;
• and
• wherein the measuring means comprises optical measuring means.