Screw Jacks and Pulley Blocks

usually the manudacturers (at least in europe) give such indications in their catalogues. For the pulleys blocks you find every thing in the manuals for lifting machines it is only a problem of "efficienci" at each end of turn.

thank you for your response, I did try them but not much Joy,

Could you be more specific please,

Thank Sir.

Check myriad web sites via google. For screw jacks try zimm, for other mechanical bits try BSC, CBC (conbear), TEA in .au domain.

Try here:

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

just one more thing if thats not too much to ask, wat is the difference between the mechanical advantage and velocity ratio of a screw jack???