About: http://webisa.webdatacommons.org/354711043

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	Referring now to FIG. 3, a disk 19 of suitable material, for example wood, metal or plastic, is provided at a position close to but spaced from the runner, for example about 8 to 12 inches from the runner.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com