About: http://webisa.webdatacommons.org/97477377

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	A device as claimed in claim 6 wherein said moving member has a weight which may vary, and including means for varying the perpendicular force applied to the moving member to maintain a desired gap between said first and second surfaces.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com