I am a material supplier and have not been paid for rental equipment provided on a construction project in Pennsylvania.
Yes, equipment lessors are protected under PA lien laws, and are specifically included under the definition of "subcontractor," "anyone who... suppliers or hauls materials, fixtures, machinery or equipment reasonably necessary for and actually used therein."
Two things to note regarding Pennsylvania mechanics liens.
For a full breakdown of the process, see: How to File a Pennsylvania Mechanics Lien | A Step-by-Step Guide