Sliding door closer

Claim 1

AUTOMATIC PNEUMATIC CLOSER MEANS FOR TWO COOPERATING SLIDING DOORS COMPRISING, A TUBULAR HOUSING VERTICALLY MOUNTABLE ON ONE OF TWO SLIDABLY MOUTED DOORS, MOUNTING MEANS TO MOUNT SAID TUBULAR HOUSING ON SAID SLIDING DOOR, A GUIDE MEANS IN THE TOP PORTION OF SAID TUBULAR HOUSING MOUNTABLE ON SAID DOOR WITH THE PLANE OF SAID GUIDE MEANS SUBSTIANTIALLY PARALLEL THE PLANE OF THE DOOR ON WHICH SAME IS MOUNTED, A PORTION OF SAID GUIDE MEANS BEING INSIDE SAID TUBULAR HOUSING AND A PORTION BEING THEREOUT, ANOTHER GUIDE MEANS MOUNTABLE WITH THE PLANE THEREOF SUBSTANTIALLY PARALLEL TO THE PLANE OF THE TOP EDGE OF SAID DOOR AT THE NEAR EDGE OF SAID ONE OF SAID SLIDABLY MOUNTED DOORS, ATTACHMENT MEANS MOUNTABLE ON THE NEAR EDGE OF THE OTHER OF SAID TWO SLIDABLY MOUNTED DOORS, A LINE ONE END OF WHICH IS FASTENABLE TO SAID ATTACHMENT MEANS, SAID LINE WHEN MOUNTED PASSING AROUND SAID LASTNAMED GUIDE MEANS AND OVER SAID FIRST-NAMED GUIDE MEANS, THE OTHER END OF SAID LINE PASSING DOWN INTO SAID TUBULAR HOUSING, A MEANS FOR EXERTING DOWNWARD FORCE COMPRISING, A WEIGHT SLIDABLY MOUNTED IN SAID TUBULAR HOUSING AND WHICH IS SECURED TO SAID OTHER END OF SAID LINE, A CHECK VALVE MOUNTED IN A LOWER PORTION OF SAID TUBULAR HOUSING PROVIDING WHEN OPEN COMMUNICATION BETWEEN THE LOWER PORTION OF SAID TUBULAR HOUSING INSIDE AND THE ATMOSPHERE THEREAROUND, SAID WEIGHT HAVING DISTANCES THEREACROSS RELATIVE THE CORRESPONDING INSIDE DISTANCES ACROSS SAID TUBULAR HOUSING PROVIDING A RELATIVELY SMALL ANNULUS IN CROSS SECTION THEREBETWEEN, SAID WEIGHT BEING OF LENGTH AND MASS AND SAID ANNULUS BEING OF CROSS SECTION THROUGHOUT AND OPERATING LENGTH THEREBY PROVIDING SOLE MEANS OF CONTROLLABLY RELEASING AIR CONTAINED BETWEEN THE BOTTOM OF SAID MEANS FOR EXERTING DOWNWARD FORCE AND THE WALLS OF SAID TUBULAR HOUSING AND SAID CHECK VALVE, SAID MEANS OF CONTROLLABLY RELEASING AIR COMPRISING A RELATIVELY SMALL ANNULUS BETWEEN SAID WEIGHT AND THE WALLS OF SAID TUBULAR HOUSING, EITHER OR BOTH OF SAID SLIDABLY MOUNTED DOORS BEING OPENABLY MANUALLY CAUSING WHEN MOUNTED SAID MEANS FOR EXERTING DOWNWARD FORCE TO BE RAISED, SAID CHECK VALVE ALLOWING AIR TO ENTER SAID TUBULAR HOUSING BELOW SAID WEIGHT, AND EITHER OR BOTH OF SAID SLIDABLY MOUNTED DOORS BEING AUTOMATICALLY CLOSED WHEN RELEASED BY SAID MEANS FOR EXERTING A DOWNWARD FORCE SUCH CLOSING BEING CONTROLLED BY COMPRESSED AIR INSIDE SAID TUBULAR HOUSING BELOW SAID WEIGHT, SAID COMPRESSED AIR BEING SLOWLY RELEASED BY SAID MEANS OF CONTROLLABLY RELEASING AIR.