Patent GB-300681-A (GB)
Title: Improvements in or relating to airship mooring towers
IPC: B64F1/14
Filed: 1927-08-17
Abstract: 300,681. Armstrong, Whitworth, & Co., Ltd., Sir W. G., and Brereton, C. F. Aug. 17, 1927. Anchoring.-An airship mooring tower having an arm which can tilt relatively thereto in any direction from the vertical has means for centring the arm comprising a cam surface engaged by the arm or a member carried thereby and so shaped that when the arm and surface are pressed together a uniform centring force is exerted on the arm whatever its position. Two sources of fluid pressure are employed for pressing the arm against the cam surface, a low pressure system for enabling the arm to follow the movements of the airship as it is being hauled in, and a high pressure system for forcibly centring the arms and finally locking it in its centred position. The three functions of "hunting", centring and locking are controlled by a single lever. The tilting arm has a telescopic portion controlled from the high pressure system by a separate lever. A hollow cone 22 for receiving a cone on the nose of the airship is pivoted about a tube 3 which slides within a tube 2 gimbal mounted at 4. 6 to the upper platform of the tower. Sliding within the lower end of the tube 4 is a member 13 having a ball 16 adapted to engage the cam surface 17 against which the ball is pressed by two rams 11 connected to a crosshead 12 on the member 13. During mooring operations, the centre of the cam surface is filled by a ram 18, but when it is desired to lock the arm 2 in its centred position the ram 18 is lowered and the member 13 enters the space left by the ram. The tube 3 is extended by two rams moving in cylinders within the tube 2 and is retracted when the cylinders are opened to exhaust by the pull of the mooring rope which passes down the cone and tube 3 and is passed around pulleys carried by the tube 2 and and over a pulley at the side of the tower to a winch at the ground level. Fig. 5 shows diagrammatically the fluid pressure systems for actuating the rams 11, 18 and the rams 7 for extending the tube 3. When the apparatus is required for use an air pump 29 is started to build up the required pressure in a hydro-pneumatic accumulator 30 and then a cock 31 is closed. A hydraulic pump 28 is then started and cocks 37, 55 opened to admit fluid to valve chambers 34, 54. When a valve 47 is moved to the left by a lever 49 low pressure fluid is supplied through the pipes 33, 40 to the cylinders 10 of the rams 11 so as to apply a limited restraint to the arm 2, and simultaneously high pressure fluid is supplied through the pipes 32, 41 to the ram 18 which completes the cam surface 17. A conical extension 11<a> on the ram 11 gradually closes the inlet as the arm 2 approaches the limit of its tilting movement so as to cushion it. A piston valve 59 operated by a lever 61 opens the cylinders 8 to the high pressure supply. When the airship has been attached to the cone the valve 59 is moved to put the cylinders 8 into communication with an exhaust tank 42 and as the section 3 is hauled in, conical extensions 9 on the rams 7, similar to the extension 11<a> on the ram 11, cushion the final movement. The lever 49 is then moved to the position shown whereby high pressure fluid is supplied to the rams 11 and the arm is centred. The valve 47 is then moved to the right whereupon the ram 18 is opened to exhaust and is forced down by the pressure of the rams 11. The cocks 37 and 55 are then closed and the pump 28 stopped. A cock 36 enables the pressure in the ram 30 to be initially adjusted if necessary by supplying fluid from the high pressure system.