well looking at that it doesnt look like the norm of robot actuators due to the shape and the chain drive thing??

also i would personally for the money want more than 40kg of push

how about this? yes from the us but its just an example

you could double the votage which would then x4 the force giving upto 2.4tonnes i think that might be wrong with my clculations but on 12volt its still powerful

thats what i would call a usual linear actautor

http://cgi.ebay.com/NEW-INDUSTRIAL-LINEAR-ACTUATOR-12-VOLT-ACTUATORS_W0QQitemZ330275819674QQcmdZViewItem?hash =item330275819674&_trkparms=72%3A570%7C39%3A1%7C66 %3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14http://cgi.ebay.com/NEW-INDUSTRIAL-L...RS_W0QQitemZ33 0275819674QQcmdZViewItem?hash=item330275819674&_tr kparms=72%3A570%7C39%3A1%7C66% 3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14