Lock pin cylinder

13:19 May 20, 2019 

Ah yes, that now confirms my interpretation, that these are cylinders whose function is to operate 'lock pins'.
It is so important not to be led astray here by seeking to interpret the EN s/t with a FR word order! As an EN native speaker myself, it is not difficult for me to make sense of this, taking into account the implication of the word order: this is not a 'cylinder' that has a 'lock' on its 'pin' (actually, rod) — for which the logical EN word order would have made it a 'pin-lock cylinder'.

12:20 May 20, 2019 

Lock pins
When the box is fully lifted and stops, two pneumatic lock pin cylinders extend to secure the box at the top.
This is a safety device to prevent the box from falling in the unlikely event that pressure is lost on the box lift cylinders.

Il semble que les "lock pin cylinders" soient un dispositif de sécurité venant en complément des "box lift cylinders".