Hi
I read your requirements carefully and because of my experiences in scissor elevator and balancer I suggest you to use these! You can add roller on their top for moving heavy box easier! I’m mechanical engineer with more than 10 years of experience in design fields especially elevators (as I mentioned), Assist, Automotive parts for OEM and market, electronic and robotic machine, delivery drone, industrial facilities and furniture. I work with NX , CATIA, SOLIDWORKS, PTC Creo and AutoCAD. I’ve worked with many different material like: plastic (POM, PA 30%GF, PE, PTFE etc.), metal (stainless steel 316, 304, CK67, CK 45 and other heigh carbon steel) , AL, Brass and Zamak 2 and 5 . I can extract cod with POWERMILL and the other software because I have much experience in CNC parts (milling or lathe). I’m expert in 2D drawings with all the required standards (like ASME, DIN etc.) and tolerances (Dimensional and geometrical tolerances: GD&T). please take a look at my portfolio!