Piston for threading lines through a conduit

Claim 1

FOR USE WITH A CONDUIT HAVING A PAIR OF OPEN ENDS, APPARATUS FOR THREADING A LINE THROUGH THE CONDUIT COMPRISING, (A) A VACUUM SOURCE AT ONE END OF THE CONDUIT, (B) NOZZLE MEANS IN RELATIVE AIR-SEALING ENGAGEMENT BETWEEN THE SAID END OF THE CONDUIT AND SAID VACUUM SOURCE AND HAVING A PORTION PRESENTED TO THE CONDUIT INTERIOR AT THE END THEREOF, (C) A PISTON INSERTED AT THE OTHER END OF THE CONDUIT HAVING A CLOSED CELL BODY PORTION FOR PREVENTING AIR PASSING THERETHROUGH AND A ROD EXTENDING AXIALLY THROUGH SAID BODY WITH ENDS OUTWARDLY THEREOF AND GUIDE MEMBERS ON SAID ROD AT EACH END OF SAID BODY PORTION, SAID GUIDE MEMBERS HAVING SPACED PORTIONS EXTENDING OUTWARDLY FROM THE RESPECTIVE END OF THE BODY PORTION TO PROVIDE AN INTERRUPTED FORWARD SURFACE, (D) A LINE SECURED TO A ROD END WHEREBY SAID VACUUM SOURCE MAY BE ATTACHED TO DRAW SAID PISTON THROUGH SAID CONDUIT, THE EXTENDING PORTIONS ON THE GUIDE MEMBERS AT THE LEADING END OF THE BODY BEING DRAWN TO THE NOZZLE FOR CONTACT OF SAID INTERRUPTED SURFACE WITH SAID PRESENTED PORTION OF SAID NOZZLE MEANS AT SPACED POINTS AND SAID VACUUM TO THE CONDUIT AND BODY BEING BROKEN IMMEDIATELY SAID NOZZLE IS DISENGAGED FROM SAID CONDUIT.