| 摘要 |
455,346. Pneumatic despatch apparatus. LAMSON PNEUMATIC TUBE CO., Ltd., and BURL, H., 132, Cheapside, London. May 27, 1936, No. 14971. [Class 78 (i)] A chamber 4 is connected to a despatch terminal 1 of a pneumatic despatch tube adjacent the door 2 and is provided with a valve 6 slidably mounted on a piston rod 7 which itself is slidably mounted in guides 10a, 11, the latter being secured to a diaphragm 9. The lower part of the chamber communicates with atmosphere through an opening 5 and a piston 10 is secured to the upper end of the rod 7. When the system is out of use a pin 15 is projected into the part of the valve 6 to limit its downward movement, but when the system is operative the pin is retracted against a spring 18 by suction in a subsidiary pipe 20 acting on a diaphragm 16. When the door 2 is opened the vacuum in the chamber 4 is destroyed and the valve 6 falls down the rod 7 and atmospheric pressure is admitted to the chamber 4 and suction pipe. When the carrier reaches its destination the suction causes a rush of air past the piston 10 whereby the latter and the rod 7 are raised until a projection 12a on the rod contacts with and closes the valve 6. A valve 12 in the diaphragm 9 is closed by a plate 13 on the rod as the latter rises and the diaphragm is flexed upwardly, an adjustable air-inlet valve 14 in the chamber beneath the diaphragm controlling the rate of upward travel of the piston. The valve 6 remains closed under the atmospheric pressure on its lower face and the piston 10, rod 7 and diaphragm 9 now descend under their own weight thereby resetting the device ready for the insertion of another carrier. The initial downward movement of the piston rod opens the valve 12 whereby the downward movement is continued unrestrictedly. |
