Yes: I thik this is out to date. I sugest to visit this one better:
viewtopic.php?f=25&t=3070&start=10In that post and images below is shown my present HEXA, with retractable legs that works very well. I´ve tried a lot of solutions for retractable legs, from complex mechanisms to this simple one and I kept this because the motors has a "current" protection system in case the motor is stoped in between the race (not an end position). This particularity permits to open only 60º (nominal is 90º from extreme to extreme) and maintain a certain force when in legs reach up position.
So, the design is done in such a way that when legs reach the upper position, that its not still the end of race, then it´s stoped against the HEXA arm, and then the internal protection system of the motor will cut the current in about 1second. So it acts as a real clamping system keeping the legs up WITH a force. This can´t be done with a standard servo system, unless you´ll burn it after a while.
Hope I´ve explained enough the principle.