Spindle drives in aircraft maintenance platforms
Due to the dimensions available in the aircraft construction, individual modules with a weight of up to 4500 kg are grouped in larger units and mechanically or electrically coupled with each other depending on spatial conditions. The group can be subsequently synchronously height-adjusted.
The project required a stroke of 1600 mm at a speed of 520 mm per minute. Limit position sensors monitor the maximum adjustment path. All adjustment drives installed in the group are synchronised in the master / slave principle. The drives used are characterised by a jerk-free soft start and soft stop. This results in a high degree of operating comfort. Elastic contact strips with a switch-off function protect the aircraft fuselage against damage.
The control is equipped with an enabling button. With this a second operator, at a position that may not be visible to the main operator, is prompted to enable the adjustment. If one of the two operators interrupts the control contact then the adjustment movement is halted.
The electromechanical safety concept encompasses the self-locking effect of the spindle-nut package, an additional holding brake, minimisation of the guide tube play, and a safety nut. The safety nut performs load-free movement on the spindle in normal operation. The load is held or adjusted by the so-called support nut. If a support nut should break, the load is transferred to the safety nut. This state is monitored by the control.
Image: Load test on the company’s own test rig.