Pneumatic self-propelled apparatus

Claim 1

APPARATUS FOR SELF-PROPULSION ALONG A DUCT OR THE LIKE, HAVING AN ELONGATED PENUMATICALLY OPERABLE TELESCOPIC BODY PORTION, FIRST AND SECOND INFLATABLE BAG GRIPS SUPPORTING THE BODY PORTION AT ITS LEADING AND TRAILING ENDS RESPECTIVELY, A FLUID INLET FOR CONNECTING A PNEUMATIC PRESSURE SOURCE TO THE APPARATUS, MEANS PERMITTING INFLATION OF THE FIRST AND SECOND BAG GRIPS SUFFICIENTLY FOR A BAG GRIP SO INFLATED TO FIRMLY GRIP THE DUCT WALL PREVENTING MOVEMENT OF THAT BAG GRIP ALONG THE DUCT, THE BODY PORTION INCLUDING PENUMATIC PRESSURE DISTRIBUTOR VALVE MEANS MOVABLE BETWEEN FIRST AND SECOND OPERATIVE POSITIONS FOR DISTRIBUTING PNEUMATIC PRESSURE FROM THE FLUID INLET ALTERNATELY TO EXTEND THE BODY PORTION WITH THE TRAILING END BAG GRIP INFLATED TO FIRMLY GRIP THE DUCT WALL AND WITH THE LEADING END BAG GRIP SUFFICIENTLY DEFLATED TO PERMIT SLIDING MOVEMENT THEREOF ALONG THE DUCT, AND TO CONTRACT THE BODY PORTION WITH THE LEADING END BAG GRIP INFLATED TO FIRMLY GRIP THE DUCT WALL AND WITH THE TRAILING END BAG GRIP SUFFICIENTLY DEFLATED TO PERMIT SLIDING MOVEMENT THEREOF ALONG THE DUCT, A FIRST CONTROL VALVE OPERABLE BY AND DURING THE SAID EXTENSION OF THE BODY PORTION TO PERMIT THE SAID DEFLATION OF THE FIRST BAG GRIP, A SECOND CONTROL VALVE OPERABLE BY AND DURING THE SAID CONTRACTION OF THE BODY PORTION TO PERMIT THE SAID DEFLATION OF THE SECOND BAG GRIP, AND RESILIENT MEANS COUPLING THE BODY PORTION AND THE DISTRIBUTOR VALVE MEANS, SAID RESLIENT COUPLING MEANS BEING RESPONSIVE TO THE SAID EXTENSION AND CONTRACTION OF THE BODY PORTION TO EFFECT THE SAID MOVEMENT OF THE DISTRIBUTOR VALVE BETWEEN SAID FIRST AND SECOND OPERATIVE POSITIONS.